behavior

JoVE Behavior documents observational and experimental techniques that seek to understand human and animal behavior. Work in this field includes analysis of genetic causes and physiological responses to internal or external stimuli as well as the implicated brain regions.

Comportamiento

biochemistry

JoVE Biochemistry publishes experiments that investigate the structure, function, and interactions of biological molecules. The video articles in this section demonstrate methods to study nucleic acids, proteins, carbohydrates and lipids as well as enzyme function, protein folding, molecular interactions and biochemical reactions.

Bioquímica

bioengineering

JoVE Bioengineering merges both physical and life sciences to understand and predict biological processes. Applying physical science tools to life science questions allow for the discovery of better technologies to measure, diagnose, and clinically treat disease.

Bioingeniería

biology

JoVE Biology welcomes all general biology research methodologies. Content in this section canvases all fields of cell, molecular, and organismal biology, ranging from new applications of standard techniques to novel approaches aimed at understanding the functions of life and living organisms. This diverse section includes, but is not limited to, techniques in physical biology, cellular biochemistry, genetics, physiology, systems biology and a combination of eukaryotic and prokaryotic model systems.

Biología

cancer research

JoVE Cancer Research illustrates experimental approaches in biomedical research and clinical practice aimed at understanding, detecting, treating and preventing cancer. The video articles in this section demonstrate methods to study the cellular and molecular mechanisms of cancer, animal models of cancer research, development of new therapies and diagnostics, tumor imaging, chemical and radiation treatments, surgical procedures and improvements in therapy. These video articles offer researchers and clinical practitioners an efficient way to learn the technologies and experimental methods in cancer research.

Investigación sobre el cáncer

chemistry

JoVE Chemistry surveys a broad scope of chemical disciplines. This collection includes fundamental and applied research that investigates molecular interactions, properties, and structure spanning in the following core divisions: analytical, organic, organometallic, inorganic, bioinorganic, and biochemistry. This section also includes the design and preparation of materials and small molecules for advanced or unique applications.

Química

developmental biology

JoVE Developmental Biology publishes research methodologies in the field of developmental biology. This includes methods that are used to study biological development in vitro and in vivo at the molecular, cellular, tissue, organ and whole organism levels.

Biología del Desarrollo

engineering

JoVE Engineering encompasses a broad range of experimental and instrumental techniques utilized in physics research. Investigations in this area strive to address and answer a broad range of scientific questions, such as device mechanisms and efficiencies, using physical tools. This approach often requires a combination of specialties, and research in this area tends to be interdisciplinary with contributions from mechanical, electrical, and chemical engineers.

Ingeniería

environment

JoVE Environment is dedicated to research methodologies that address environmental concerns and seek to better understand Earth's ecosystem.  Special consideration is given to experimental methodologies that assess society’s impact on the environment, suggest solutions for protecting Earth’s resources, and develop sustainable fuel sources. Moving towards an environmentally conscious planet is a collaborative effort with contributions from both life and physical scientists.

Medio ambiente

genetics

JoVE Genetics publishes video articles demonstrating experimental approaches to investigate gene function and regulation. This includes methods to study gene expression, mutagenesis, epigenetics, genetic determinants of development, genetic disorders, population genetics and evolution.

Genética

immunology and infection

JoVE Immunology and Infection includes content from a variety of fields working toward a shared initiative of improving global health. Techniques evaluating the biological response to pathogens from the molecular to organismal level are presented as well as therapeutic agents and their efficacy in treating disease.

Inmunología e Infección

medicine

JoVE Medicine serves as a connection between basic research and clinical applications. Articles may present medical procedures, case studies or clinical trial methodologies. Included studies are often modeled towards predictive, preventative, personalized, and practical approaches to treatment of disease. The goal of research methodologies in this section is to improve overall patient care and prognosis.

Medicina

neuroscience

JoVE Neuroscience is a multidisciplinary section devoted to investigations of the structure, function, physiology, and pathophysiology of the brain and nervous system. Included methodologies range from molecular and cellular level studies to full central and peripheral neural systems. Potential treatment platforms and surgical techniques for neurological diseases and disorders are also presented in this section.

Neurociencias

jove journal

JoVE Journal

Revista de vídeos científicos. Revisada por pares. Multidisciplinaria. Indexada en PubMed y Web of Science.

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Research

Psychosurgery

Psychosurgery, the surgical alteration or permanent removal of brain tissue to alleviate severe psychological conditions, stands as one of the most radical and controversial treatments in the history of mental health care. Its development and application have evolved significantly, marked by dramatic shifts in scientific understanding and ethical perspectives.
Historical Development of Psychosurgery
In the 1930s, Portuguese neurologist Antonio Egas Moniz introduced a surgical procedure designed to sever neural pathways between the frontal lobe and thalamus. This intervention aimed to mitigate severe mental health disorders, including schizophrenia and severe anxiety. Despite its crude methodology, the surgeries gained recognition, and Moniz was awarded the Nobel Prize in Physiology or Medicine in 1949.
Walter Freeman, an American neurologist, popularized and coined the term prefrontal lobotomy in the United States, introducing a simplified and faster technique that involved accessing the brain through the eye socket using a surgical instrument similar to an ice pick. Freeman performed over 3,000 lobotomies, often in public demonstrations, and fervently advocated for the procedure as a solution to various psychological disorders. However, his approach often overlooked long-term outcomes and ethical considerations.
Decline of Traditional Lobotomies
The widespread adoption of lobotomies from the 1930s to the 1960s resulted in significant and irreversible harm to many patients. Adverse effects included severe cognitive impairments, memory loss, emotional flatness, and personality changes. Coupled with the advent of psychiatric medications in the mid-1950s, which offered non-invasive alternatives, lobotomies fell out of favor. Reports of poor outcomes and heightened ethical scrutiny further discredited the procedure.
Modern Psychosurgical Techniques
Contemporary psychosurgery employs far more precise and controlled methods, targeting specific brain regions such as the amygdala or anterior cingulate cortex. Techniques like cingulotomy and capsulotomy are used to treat intractable psychiatric conditions such as severe obsessive-compulsive disorder (OCD) and major depressive disorder. These procedures are guided by advanced imaging technologies to minimize damage to surrounding tissues.
Stringent regulations, such as institutional review boards, now govern psychosurgery, ensuring thorough patient evaluation, informed consent, and surgeon&#39;s competency. These measures aim to balance the potential benefits of psychosurgery with its inherent risks, emphasizing its use as a last resort when all other treatments have failed.
Ethical and Scientific Considerations
Despite technological advances, psychosurgery remains a contentious field. Critics point to the procedure&#39;s historical misuse and potential for unintended consequences, while proponents argue for its value in treating otherwise untreatable conditions. Ongoing research seeks to refine surgical techniques and deepen understanding of the brain, underscoring the need for a cautious and ethical approach to this powerful intervention.

Psychosurgery involves removing or permanently destroying brain tissue to treat severe psychological conditions, making it a controversial biomedical ...

Interpersonal Psychotherapy

Interpersonal psychotherapy (IPT) is a structured, time-limited therapeutic approach initially developed to treat depression. It integrates key concepts from psychodynamic, humanistic, and cognitive-behavioral therapies, making it a uniquely eclectic framework. The therapy is rooted in the interpersonal theories of Adolph Meyer and Harry Stack Sullivan, as well as John Bowlby&#39;s attachment theory, and focuses on the interplay between interpersonal relationships and emotional well-being.
Foundations of Interpersonal Psychotherapy
The foundational premise of IPT is that interpersonal relationships significantly influence mood and psychological health. Sullivan emphasized the collaborative role of the therapist as a &#34;participant observer,&#34; working to identify and address maladaptive interpersonal patterns in the client&#39;s daily life. This focus on relationship dynamics distinguishes IPT from other therapeutic models. While it draws on psychodynamic concepts, IPT diverges from traditional psychodynamic therapy by explicitly emphasizing practical strategies to improve interpersonal functioning.
Structure and Scope of IPT
IPT is typically delivered in a short-term format, encompassing 12&#8211;16 sessions. The approach aims to enhance clients&#39; social skills, resolve interpersonal conflicts, and assist with life transitions, such as childbirth, retirement, or bereavement. The therapy is structured around specific problem areas identified during the initial assessment, such as role disputes, role transitions, unresolved grief, or interpersonal deficits. By addressing these areas, IPT helps clients develop healthier relationships and coping mechanisms.
Effectiveness Across Conditions
Originally designed to treat depression, IPT has demonstrated efficacy in combination with pharmacological treatments and as a standalone intervention. Clinical studies have shown its effectiveness in treating various conditions, including substance use disorders and eating disorders, with outcomes comparable to those achieved through cognitive-behavioral therapy. IPT&#39;s success lies in its ability to adapt its core principles to address the unique challenges associated with different mental health disorders.
The integration of theoretical insights with practical strategies makes IPT a versatile and evidence-supported approach, offering a collaborative pathway to improved interpersonal functioning and psychological health.

Interpersonal psychotherapy, or IPT, is an insight-based therapy focusing on the relationship between an individual&#39;s mood and their interpersonal ...

Community Based Intervention

Community-based interventions in mental health represent a paradigm shift from institution-centered care to treatments embedded within the fabric of local communities. By prioritizing inclusion and leveraging existing societal structures, this approach fosters a supportive environment conducive to addressing mental health challenges while promoting individual dignity and agency.
Foundations of Community Mental Health Programs
Central to the success of community-based interventions is the training of local stakeholders such as teachers, nurses, and community members. These individuals are equipped with fundamental counseling skills and are often involved in workshops aimed at stress management, substance abuse reduction, and interpersonal skill development. Such initiatives help extend mental health care beyond specialized professionals, making it more accessible and reducing stigma.
The deinstitutionalization movement of the 1960s marked the beginning of this transition. It was driven by concerns over the ethical failings of institutional care, which often subjected individuals to neglect and abuse, and by economic considerations regarding the unsustainable costs of long-term institutionalization. As individuals were reintegrated into communities, the focus shifted to creating support systems that address mental health in a holistic, culturally sensitive manner.
Empowerment and Sustainability
Community-based mental health programs emphasize empowerment, enabling individuals to actively engage in their recovery and integrate fully into familial and societal contexts. This approach, championed by community psychologists, seeks to cultivate long-term well-being by embedding care within the individual&#39;s social and cultural milieu.
However, these programs require robust support in terms of local resources and government funding. Sustainable initiatives are essential to ensure continuity in care and to prevent adverse outcomes, such as homelessness, for individuals with chronic mental health conditions. Investment in community-based interventions not only alleviates the strain on formal healthcare systems but also promotes a more inclusive and equitable approach to mental healthcare.

Community-based intervention provides care within society and family, fostering inclusion and treating mental health in familiar settings like community ...

Couples Therapy

Couples therapy is a therapeutic approach designed to help individuals in intimate relationships address conflicts, improve communication, and foster healthier dynamics. It is appropriate for couples at various stages, including those who are dating, married, or in long-term partnerships, and aims to support partners in navigating their unique relational challenges.
Core Principles and Techniques
Couples therapy often incorporates cognitive-behavioral principles to identify and modify negative patterns within relationships. Therapists guide partners in understanding how their individual backgrounds, beliefs, past experiences, and behaviors influence their interactions. This insight is crucial in addressing issues such as poor communication, infidelity, jealousy, sexual difficulties, substance abuse, and the complexities of blended families or two-career households.
Therapists use various techniques such as validation, reframing, structural change, and detriangulation to promote relational growth. Validation involves acknowledging each partner&#39;s emotions and beliefs, as well as fostering mutual respect and understanding. Reframing helps couples view their challenges as shared problems rather than assigning blame, encouraging collaboration. The structural change focuses on reorganizing interaction patterns to create a supportive and functional environment, while detriangulation addresses external conflicts that may be diverting attention from the relationship itself.
Navigating High-Conflict Relationships
High-conflict relationships present unique challenges due to heightened emotions and volatility. Therapists act as mediators, helping partners navigate intense disagreements and work toward constructive resolutions. These situations require a nuanced approach to de-escalate tensions and facilitate productive dialogue.
Goals and Outcomes
The primary goal of couples therapy is to equip partners with tools to enhance understanding and foster healthier interactions. For some, this process strengthens the relationship, while for others, therapy may reveal irreconcilable differences, leading to a mutual decision to separate. Regardless of the outcome, therapy emphasizes clarity and informed decision-making, enabling couples to navigate their circumstances with greater insight and confidence.
By addressing relational dynamics and promoting constructive change, couples therapy supports partners in building more harmonious connections or reaching resolutions that align with their well-being.

Couples therapy helps individuals in intimate relationships resolve conflicts and improve dynamics. Couples may be dating, married, or in long-term ...

Self-Help Support Groups

Self-help support groups are voluntary, community-based organizations that provide a platform for individuals with shared concerns to exchange support, insights, and practical strategies for coping with life challenges. Typically led by group members or paraprofessionals, these groups form a cornerstone of mental health care, especially in reaching populations that are underserved by traditional healthcare systems.
Accessibility and Cost-Effectiveness
One of the primary strengths of self-help groups is their accessibility. By leveraging community resources and operating at a low cost, they serve individuals who might otherwise face barriers to mental health services, such as those with limited financial means or lower levels of education. These groups offer an inclusive space where participants can openly share experiences, seek advice, and explore solutions in a non-judgmental environment.
The Power of Shared Experience
The effectiveness of self-help groups is rooted in their emphasis on shared experience. Participants gain unique insights from peers who have faced similar challenges, fostering a sense of credibility and understanding that professionals may not always provide. For instance, a rape survivor might find meaningful support and guidance from another survivor who has successfully navigated a similar recovery process. These interactions not only validate individual experiences but also enhance emotional resilience and promote self-efficacy.
Applications in Mental Health and Beyond
Self-help groups address a wide array of issues, including substance abuse, chronic illnesses such as heart disease or cancer, and psychological trauma. Alcoholics Anonymous (AA) exemplifies the impact of these groups, with research highlighting its role in reducing alcohol consumption through mechanisms such as enhanced social networks, improved self-efficacy, increased spirituality, and alleviation of negative emotions.
The Role of Online Platforms
Advances in technology have expanded the reach of self-help groups through online platforms, offering greater accessibility for individuals unable to attend in-person meetings. However, virtual settings pose unique challenges, including the risk of misinformation. In the absence of guidance from a trained professional, members may lack the expertise and knowledge to provide optimal advice. This increases the potential for harmful group dynamics, as evidenced by certain pro-anorexia communities. Effective moderation by group leaders can mitigate these risks, ensuring a safe and constructive environment for all members.
Self-help groups exemplify the value of peer-led initiatives in mental health care, bridging gaps in accessibility and fostering collective resilience through shared understanding and mutual support.

Self-help support groups are voluntary organizations where individuals with common interests meet regularly to discuss shared concerns and provide mutual ...

Family Therapy

Family therapy conceptualizes psychological challenges as arising from dysfunctional interactions within the family unit, rather than as isolated issues within individuals. This approach seeks to address and transform the patterns of communication, roles, and relationships within families to promote healthier dynamics and emotional well-being for all members.
Strategic Family Therapy
Strategic family therapy emphasizes resolving communication barriers and improving problem-solving abilities among family members. Therapists employ carefully planned tasks, known as directives, to alter dysfunctional interaction patterns. One notable technique is the use of paradoxical requests, where problematic behaviors are reframed in unexpected ways to elicit change. For example, a couple prone to frequent arguments might be instructed to argue more intentionally, thereby reframing their conflict as an expression of connection. This paradoxical approach often leads to reduced conflict and an improved relationship dynamic by altering the way family members perceive and engage in their interactions.
Structural Family Therapy
Structural family therapy focuses on reorganizing the family&#39;s hierarchical structure and boundaries to enhance functionality. Therapists actively participate in family activities to observe and modify interactions, fostering healthier dynamics. For instance, helping a teenager who initially sought their family&#39;s attention by refusing to eat to express their needs verbally, ultimately leading them to stop using food refusal as a way to seek affection. This direct engagement strengthens communication, reinforces healthy boundaries, and empowers the family to support each member&#39;s needs effectively.
Effectiveness and Applications
Research demonstrates that family therapy is as effective as individual therapy, offering distinct advantages for families dealing with relational or systemic issues. By addressing problems within their broader context, family therapy promotes growth and healing not just for individuals but for the family as a cohesive unit. Approaches such as strategic and structural therapy exemplify the flexibility and efficacy of this modality, making it a valuable tool in fostering healthier familial relationships and emotional resilience.

Family therapy views psychological problems as rooted in dysfunctional family systems rather than in an individual.
The primary focus of treatment is the ...

Electroconvulsive Therapy

Electroconvulsive therapy (ECT), or shock therapy, remains a critical biomedical intervention for severe, treatment-resistant depression. While its origins can be traced back to Hippocrates&#39; observations that malaria-induced convulsions alleviated mental illness, modern ECT has evolved significantly from its earlier, more primitive applications. First introduced in 1938 by Ugo Cerletti and his colleagues, ECT involves inducing controlled seizures using electrical currents. In its early years, patients were subjected to the procedure without anesthesia, leading to severe bodily convulsions and a barbaric reputation. Today, however, ECT is far more refined and safer due to anesthesia, muscle relaxants, and targeted stimulation.
The current ECT procedure involves administering a brief electric pulse, typically lasting less than a second, through electrodes placed on the patient&#39;s scalp. This electrical current triggers a seizure lasting approximately 60 seconds. Patients are rendered unconscious with anesthesia and muscle relaxants to prevent physical convulsions, ensuring minimal discomfort. Increasingly, the stimulation is applied to the brain&#39;s right hemisphere, reducing the risk of memory loss and cognitive impairments, which are among ECT&#39;s most debated side effects. Patients awaken shortly after the procedure with no memory of the treatment, and recovery occurs within 30 minutes.
ECT is primarily used for individuals with severe depression who do not respond to medication or psychotherapy. It is particularly effective for cases involving acute suicidality, offering rapid mood improvement. Studies report that after two to four weeks of treatments &#8212; typically three sessions per week &#8212; approximately 70% of patients experience significant relief. This success has been attributed to ECT&#39;s ability to reduce overactivity in brain regions associated with depression and potentially stimulate neurogenesis, promoting the growth of new neurons and synaptic connections.
Despite its effectiveness, ECT remains controversial due to its side effects, including memory loss and cognitive impairment. Though modern advancements, such as unilateral stimulation and refined protocols, have reduced these risks, they still warrant careful consideration. Long-term efficacy also remains uncertain, as relapses can occur, necessitating maintenance therapies like antidepressants or exercise. Nonetheless, ECT continues to save lives, especially in severe cases of depression where other treatments fail. For many, its benefits far outweigh the risks.

Electroconvulsive therapy, or ECT, commonly known as shock therapy, originated from Hippocrates&#39; observations in ancient Greece, who noted that ...

Rational Emotive Behavior Therapy

Cognitive-behavioral therapies (CBTs) are grounded in the belief that our thoughts profoundly influence our emotions and actions. Advocates of CBT emphasize three core assumptions: first, that cognitions are identifiable and measurable; second, that they are central to psychological functioning; and third, that irrational or maladaptive beliefs can be replaced with rational and adaptive ones. This transformative approach to therapy has paved the way for specific models such as Albert Ellis&#39;s Rational Emotive Behavior Therapy (REBT), which integrates both cognitive and behavioral elements to foster mental well-being.
The ABCs of Rational Emotive Behavior Therapy
Ellis introduced REBT in the mid-1950s as a pioneering cognitive-behavioral framework. At its core lies the ABC model, which outlines the interaction between activating events (A), belief systems (B), and emotional and behavioral consequences (C). For instance, two individuals receiving the same test score may exhibit vastly different responses due to disparities in their belief systems. Rational beliefs, characterized by flexibility and self-acceptance, contrast sharply with irrational beliefs, which often involve unrealistic demands and catastrophic thinking.
To address irrational beliefs, Ellis extended the ABC model to include disputation (D), effective new beliefs (E), and fostering desired feelings and behaviors (F). Therapists employing REBT actively challenge clients&#39; maladaptive beliefs and encourage rational rethinking. Assignments or &#8220;homework&#8221; often reinforce this process, such as tasks designed to confront and disprove fears tied to irrational thoughts.
Cognitive-Behavioral Therapy: Expanding on Rationality
CBT builds upon the principles of cognitive psychology and behaviorism, focusing on present cognitive and behavioral interactions rather than past influences. It posits that psychological disorders stem from illogical thought patterns, which, when restructured into logical and rational frameworks, lead to symptom alleviation. The three overarching goals of CBT include symptom relief, equipping clients with coping strategies, and fostering a shift from self-defeating to self-enhancing thoughts.
By blending cognitive interventions with behavioral techniques, CBT offers a robust, action-oriented approach to mental health, emphasizing the transformative power of rational thinking and adaptive behavior.

In the mid-1950s, Albert Ellis developed rational emotive behavior therapy or REBT, a key example of a cognitive-behavioral approach.
He introduced the ...

Cognitive Therapy

Cognitive therapy, pioneered by Aaron T. Beck in the 1960s, is a structured approach to addressing psychological distress by focusing on the influence of thoughts on emotions and behaviors. All cognitive therapies involve the basic assumption that human beings have control over their feelings, and that how individuals feel about something depends on how they think about it. Unlike psychoanalytic methods that delve into unconscious processes or humanistic approaches emphasizing self-actualization, cognitive therapy targets distorted or dysfunctional thought patterns, aiming to restructure these to alleviate maladaptive behaviors and emotional responses.
Principles of Cognitive Therapy
Central to cognitive therapy is the concept of cognitive restructuring, which involves identifying and modifying distorted thinking patterns (cognitive distortions). For example, a client may interpret a single academic failure as indicative of global incompetence, leading to feelings of worthlessness. Through guided questioning, therapists challenge these irrational beliefs and help clients develop more accurate, rational perspectives. This active and structured process distinguishes cognitive therapy as an action-oriented approach rather than one focused on uncovering historical psychological roots.
Application to Depression and Other Disorders
Initially developed to treat depression, cognitive therapy has demonstrated effectiveness across a range of psychological disorders. Beck&#39;s work emphasized the role of self-defeating attitudes and negative automatic thoughts in perpetuating depressive states, even amidst positive life circumstances. By addressing these maladaptive cognitions, clients can reframe their interpretations of situations, reducing distress and promoting healthier emotional responses.

Cognitive therapy is a form of psychotherapy that emphasizes the role of thoughts in causing emotional distress and maladaptive behaviors.
It aims to ...

Beck's Cognitive Therapy

Cognitive therapy is a psychological approach designed to address distortions in thinking, which can lead to negative emotions and unrealistic beliefs. These cognitive distortions often influence how individuals interpret and respond to situations, exacerbating emotional distress. Below are some prevalent cognitive distortions, their characteristics, and examples of how they manifest in thought processes.
Arbitrary Inference
Arbitrary inference involves making conclusions without sufficient evidence, often based solely on personal assumptions. This type of distortion disregards facts and relies on conjecture. For example, an individual may interpret a canceled lunch appointment as evidence that their friend is seeing someone else, despite having no supporting evidence. This tendency to jump to conclusions can lead to unwarranted anxiety or mistrust.
Selective Thinking
Selective thinking occurs when a person fixates on one aspect of a situation, ignoring other relevant details that might provide balance or perspective. For instance, a student might receive praise for their work but focus entirely on a minor critique, concluding that their performance was poor. This cognitive bias limits the individual&#39;s ability to see the broader context of their achievements or the constructive nature of feedback.
Overgeneralization
Overgeneralization involves drawing broad, often exaggerated conclusions based on a single incident. For example, someone reprimanded at work might irrationally assume that their work relationships are doomed and envision a cascade of negative outcomes. This distortion perpetuates feelings of hopelessness and unwarranted despair.
Magnification and Minimization
In this distortion, individuals amplify the significance of negative events while downplaying positive ones. For example, a student who consistently excels academically might catastrophize a single mediocre grade as a sign of inevitable failure, disregarding their overall success. This imbalance skews self-assessment and fosters unwarranted negative self-perceptions.
Personalization
Personalization involves taking unwarranted responsibility for external events. For example, a person might attribute their partner&#39;s bad mood to their actions, ignoring external factors such as work-related stress. This distortion often results in misplaced guilt or self-blame.
Cognitive therapists aim to address these distortions by encouraging clients to evaluate their beliefs critically. Through structured questioning, such as examining the origin or evidence of a belief, clients are guided to identify and challenge illogical patterns. This process fosters more balanced and realistic thinking, improving emotional well-being and resilience.

Cognitive therapy, developed by Aaron T. Beck, addresses distorted thinking and unrealistic beliefs, particularly in depression.
Some of the common ...

Group Therapy

Group therapy is a sociocultural approach to psychological treatment, where individuals with shared psychological challenges come together under the guidance of a mental health professional. This therapeutic modality offers unique opportunities for individuals to connect, share, and grow within the context of a supportive group. By fostering mutual understanding and collaboration, group therapy can address a range of psychological concerns effectively, often complementing or surpassing the benefits of individual therapy.
Benefits of Group Therapy
Group therapy promotes universality, helping participants realize that others share similar struggles, which can reduce feelings of isolation and shame. For instance, a child dealing with poor social skills may benefit from observing and practicing interpersonal techniques within a structured group setting. Similarly, a woman with postpartum depression might feel less guilt and more connection in a group of others facing the same challenges.
Altruism is another key feature: participants provide support, advice, and empathy to one another, which can enhance feelings of competence and efficacy. Additionally, the group environment fosters interpersonal learning, where individuals receive feedback from peers, enabling them to refine social behaviors and develop healthier interaction patterns. For those with specific needs, such as sexual abusers, group therapy offers a safe space for practicing social skills, modeling openness, and confronting harmful patterns.
Challenges and Considerations
While group therapy has significant advantages, it is not without challenges. Participants may initially feel reluctant to share personal issues with strangers, and confidentiality concerns can arise if members disclose private information outside the group. Personality conflicts and disagreements within the group can also present obstacles. Despite these challenges, effective facilitation ensures a balanced and inclusive environment where everyone benefits from the group dynamic.
Applications and Formats
Group therapy can adopt various forms, including psychodynamic, humanistic, behavioral, or cognitive approaches. Psycho-educational groups address specific topics, such as coping with a family member&#39;s illness or overcoming bullying, often within school settings. Structured groups have defined goals and activities, while unstructured groups allow members to determine the focus collaboratively. These diverse formats cater to different therapeutic needs, making group therapy an adaptable and powerful tool for psychological growth and healing.

Group therapy is a sociocultural approach to treating psychological disorders, where individuals with similar issues participate in guided sessions led by ...

Operant Conditioning Intervention

Operant conditioning serves as a foundational principle in therapeutic interventions aimed at modifying maladaptive behaviors. Central to this approach is the notion that behaviors, both adaptive and maladaptive, are learned through reinforcement. By analyzing the environmental factors that reinforce problematic behaviors, clinicians can design interventions to weaken these reinforcements and replace maladaptive behaviors with healthier alternatives.
In operant conditioning, behaviors that are reinforced tend to recur, whereas those that are not reinforced eventually diminish or become extinct. For example, obsessive-compulsive disorder (OCD) behaviors, such as compulsive checking rituals, are maintained through negative reinforcement. A compulsive action, like repeatedly checking if a door is locked, alleviates anxiety and prevents anticipated negative outcomes, reinforcing the behavior. Therapy based on operant conditioning addresses this by extinguishing avoidance learning. The individual is gradually exposed to situations without performing the compulsion, demonstrating that the feared outcomes do not occur. Simultaneously, relaxation training and alternative coping mechanisms are introduced to reduce anxiety, breaking the cycle of compulsive reinforcement.
Behavioral therapies based on operant principles are particularly effective for populations with limited cognitive abilities, such as children or adults with developmental disabilities. In treating autism spectrum disorder (ASD), behavioral therapies have proven highly effective. It is used to address self-injurious behaviors, promote communication, and enhance cognitive and language development. Research indicates that intensive early interventions can significantly improve outcomes for children with ASD.
One widely implemented operant conditioning technique is the token economy. This method is commonly used in controlled environments, such as psychiatric hospitals, to encourage positive behaviors. Tokens, which serve as secondary reinforcers, are awarded for desirable actions and can be exchanged for privileges or rewards. For instance, patients may earn tokens for completing daily tasks or engaging in social interactions, which they can later trade for amenities like extra leisure time or preferred activities. The structured reinforcement system of token economies fosters sustained behavioral improvements across diverse clinical settings.

Operant conditioning suggests that behaviors are shaped by their consequences.
Behaviors followed by positive outcomes are reinforced, such as a child ...

Modeling in Therapy

Modeling, a key technique in therapy, uses observational learning to help clients acquire and practice new skills by watching therapists demonstrate desired behaviors. This approach, rooted in Albert Bandura&#39;s concept of vicarious learning, plays a significant role in therapeutic interventions for various psychological conditions, including social anxiety, ADHD, and depression.
Participant Modeling
Participant modeling involves therapists demonstrating calm and effective behaviors in situations that clients find challenging. The therapist first models a constructive approach to the feared object or scenario and then guides the client through the same process step-by-step until the client gains the confidence to manage independently. This technique helps clients confront their fears in a controlled and supportive environment.
Assertion Training
Assertion training incorporates modeling to help individuals express their thoughts and feelings assertively while avoiding extremes of submissiveness and aggressiveness. This training teaches clients to advocate for themselves respectfully and effectively, ensuring that their needs and rights are recognized. The focus is on fostering assertiveness as the balance between passivity and hostility, a skill particularly valuable for those with social anxiety or interpersonal challenges.
Behavioral Rehearsal
Behavioral rehearsal, often integrated with assertion training, employs role-playing exercises to enhance the client&#39;s skills. The therapist assumes the role of a significant figure in the client&#39;s life, such as a supervisor or family member, allowing the client to practice responses in a simulated interaction. As a result, role reversal enables the therapist to model ideal verbal and nonverbal communication, illustrating not just what to say but also how to say it effectively. Feedback and coaching refine the client&#39;s performance, helping them build confidence and competence.
Applications Beyond Therapy
These techniques extend beyond therapy sessions by encouraging clients to apply learned skills in real-life situations. By practicing outside the therapeutic setting, clients consolidate their learning and improve their ability to handle social interactions. Modeling and social skills training are instrumental in managing conditions such as schizophrenia, autism spectrum disorders, and ADHD, where improved interpersonal and coping skills can significantly enhance quality of life.
Through structured observation, practice, and application, modeling serves as a powerful tool in helping clients overcome barriers and adopt constructive behaviors.

Modeling allows clients to learn by watching therapists demonstrate positive behaviors, such as maintaining eye contact during conversations.
Similarly, ...

Humanistic Therapy

Humanistic therapies emphasize personal growth, self-understanding, and the fulfillment of human potential. Rooted in the belief that individuals inherently strive toward self-actualization, these approaches encourage clients to explore their feelings and experiences in a supportive, nonjudgmental environment. Humanistic therapies differ from psychodynamic approaches by focusing on conscious experiences, present circumstances, and the potential for self-improvement rather than past conflicts and unconscious drives.
Carl Rogers&#39; client-centered therapy is a cornerstone of humanistic psychotherapy. It aims to foster self-acceptance and unity between the client&#39;s actual self and ideal self. Therapists create a therapeutic environment characterized by three essential elements:
<ol>
	<li>Unconditional Positive Regard: Therapists affirm the inherent worth of clients, offering nonjudgmental acceptance to promote self-acceptance.</li>
	<li>Empathy: By deeply understanding and reflecting on the client&#39;s emotions, therapists help clients feel heard and validated.</li>
	<li>Genuineness: Therapists are authentic and transparent, fostering a genuine connection with the client.</li>
</ol>
Active listening and reflective speech are central techniques that allow clients to identify and articulate their feelings. For example, a therapist might mirror a client&#39;s grief or anger, encouraging deeper emotional exploration.
Gestalt therapy, developed by Fritz Perls, focuses on integrating conflicting aspects of the self to achieve wholeness. Techniques like the two-chair dialogue allow clients to confront and synthesize opposing parts of their personality, fostering authenticity and emotional balance. Gestalt therapy emphasizes the &#34;here and now,&#34; urging clients to take responsibility for their feelings and actions. Techniques such as the two-chair method in Gestalt therapy, where clients alternate speaking from different perspectives to address and resolve internal conflicts, help promote self-awareness and integration.
Existential therapy, exemplified by Viktor Frankl&#39;s logotherapy, explores meaning-making as a response to life&#39;s challenges. Frankl believed that even in dire circumstances, individuals could find purpose and maintain dignity. Existential therapists help clients confront themes like freedom, isolation, and mortality, encouraging personal responsibility and resilience.
Humanistic principles are integral to various contemporary approaches, including motivational interviewing, which leverages empathy and reflective listening to encourage behavior change. Whether addressing mental health conditions or lifestyle modifications, humanistic therapies remain influential in fostering emotional awareness, self-empowerment, and authentic living.

Humanistic therapy focuses on self-healing, conscious thoughts, the present, and self-fulfillment, encouraging individuals to realize their potential and ...

Psychodynamic Therapy

Psychodynamic therapies emphasize the exploration of unconscious processes and early childhood experiences as fundamental contributors to psychological difficulties. These therapies, deeply rooted in Freud&#39;s psychoanalytic theory, aim to uncover and resolve unconscious conflicts, granting individuals insights that promote emotional and behavioral healing. Contemporary psychodynamic approaches have evolved, integrating a broader range of influences and methodologies while still valuing the unconscious mind and the therapeutic relationship.
Freud&#39;s psychoanalysis is the cornerstone of psychodynamic therapies. He proposed that unconscious conflicts, often originating in childhood, manifest as present-day psychological problems. Through techniques such as free association, dream analysis, and interpretation, psychoanalysts endeavor to illuminate these hidden struggles.
Free Association encourages clients to articulate thoughts without censorship, facilitating the emergence of repressed emotions or memories. Freud viewed moments of resistance &#8212; when clients hesitated or avoided certain topics &#8212; as indicators of unresolved conflicts.
Dream Analysis involves interpreting dreams&#39; manifest content (the recalled narrative) to reveal their latent content or hidden unconscious meanings. Freud believed that dreams serve as a disguised outlet for repressed wishes, often rooted in sexual or aggressive instincts.
Interpretation entails uncovering symbolic meanings in clients&#39; words and actions and offering hypotheses about unconscious motivations that drive behaviors.
Freud highlighted the importance of transference, where clients project feelings toward significant figures in their lives onto the therapist. This phenomenon provides a window into relational patterns and unresolved emotions, which therapists can help clients process. Conversely, resistance reflects unconscious defense mechanisms that hinder therapy progress. Psychoanalysts work to address and understand these resistances, aiding clients in confronting difficult truths.
Modern psychodynamic therapies have shifted focus, often prioritizing the conscious mind and current relationships over Freud&#39;s emphasis on sexual conflicts. They explore recurring life patterns, significant past events, and distressing emotions to provide insight. Therapists, influenced by figures like Heinz Kohut, emphasize empathy and healthy therapeutic relationships as a means to foster self-understanding and emotional resilience. Contemporary practices also adapt to practical constraints, favoring weekly sessions over the intensive regimens of Freud&#39;s era.
This evolution reflects an enduring commitment to exploring the depths of the human psyche while embracing contemporary perspectives on mental health.

Psychodynamic therapy explores the unconscious mind, such as repressed memories, conflicts, and early childhood experiences, to understand current ...

Behavior Therapy

Behavior therapy incorporates diverse techniques rooted in classical conditioning principles to address maladaptive behaviors and anxiety disorders. These methods aim to reduce avoidance behaviors, foster adaptive coping mechanisms, and alter associations between stimuli and responses, making them effective in a wide range of therapeutic contexts.
Exposure therapy is a cornerstone of behavioral treatment for anxiety disorders. It involves systematic exposure to feared stimuli, either in real life, through visualization, or via virtual reality, to desensitize the individual. Gradual exposure, beginning with the least anxiety-provoking scenarios and progressing to more challenging ones, is designed to help clients build tolerance.
Systematic desensitization builds upon this by pairing exposure with relaxation techniques. For instance, someone with a fear of public speaking may practice relaxation while initially speaking to a single person and then gradually progressing to larger audiences, reducing anxiety through reciprocal inhibition.
Flooding involves directly confronting the most anxiety-inducing stimuli in a controlled setting to extinguish avoidance behaviors. Unlike graded exposure, flooding does not follow a hierarchical approach. For example, an individual with a phobia of dogs might be guided to interact with a calm and friendly dog immediately, enabling them to experience the absence of feared consequences, which helps diminish their fear response.
Aversive conditioning is employed to deter undesirable behaviors by pairing them with unpleasant experiences. For example, to address overeating, therapists may use aversive stimuli, such as a bitter taste, to create a negative association with the behavior. This method conditions the individual to avoid the maladaptive behavior due to its unpleasant consequences.
Relaxation techniques, including deep breathing and progressive muscle relaxation, are integral to these therapies. They work through reciprocal inhibition, whereby a physiological state incompatible with anxiety, such as relaxation, counteracts the anxious response. By combining relaxation with gradual or direct exposure, individuals can recondition their responses to previously feared stimuli, fostering long-term behavioral change.

In behavior therapy, a therapist employs principles of learning, such as classical and operant conditioning, to help clients change undesirable 
...

Drug Therapy

The advent of drug therapy has profoundly shaped modern mental health care, providing targeted treatments for a range of psychological disorders. Psychotherapeutic drugs, classified into antianxiety, antidepressant, and antipsychotic medications, address symptoms across anxiety disorders, mood disorders, and schizophrenia. While these medications have transformed patient outcomes, they require careful management due to their potential side effects and limitations.
Antianxiety Medications
Antianxiety drugs, commonly known as tranquilizers, include benzodiazepines such as Xanax, Valium, and Librium. These medications alleviate anxiety by binding to neurotransmitter receptors that are hyperactive during periods of distress. Although benzodiazepines act rapidly and are effective for short-term relief, they pose risks of addiction, drowsiness, impaired coordination, and potentially harmful interactions with alcohol and other drugs. Alternatives like buspirone (BuSpar) offer less addictive solutions but may take longer to provide symptomatic relief. Caution is essential in prescribing these medications, particularly for long-term use, due to their addictive potential.
Antidepressant Drugs
Antidepressants regulate mood by influencing brain neurotransmitters, particularly serotonin and norepinephrine. Types of antidepressants such as tricyclics and tetracyclics, named for their molecular structures, have demonstrated efficacy but come with significant side effects such as dizziness, memory issues, and faintness. Monoamine oxidase (MAO) inhibitors, though effective, are less commonly used due to dietary restrictions and risks of high blood pressure. More commonly prescribed are selective serotonin reuptake inhibitors (SSRIs), which target serotonin reabsorption, offering fewer side effects and broad applications for mood, anxiety, and even chronic pain disorders. However, withdrawal from SSRIs requires careful management to avoid severe symptoms.
Mood Stabilizers Medications
Lithium remains a cornerstone treatment for bipolar disorder, effectively managing manic episodes and stabilizing mood. Its therapeutic benefits are tempered by a narrow safety margin, requiring careful blood monitoring to avoid toxicity. Side effects such as weight gain, thyroid issues, and kidney complications are common, highlighting the need for patient adherence and regular medical supervision.
Antipsychotic Medications
Antipsychotics have revolutionized schizophrenia treatment by reducing symptoms such as hallucinations and agitation. Neuroleptics, the most widely used class, modulate dopamine pathways but are associated with severe side effects, including tardive dyskinesia, a condition characterized by involuntary facial and limb movements. Newer atypical antipsychotics, such as Clozaril and Risperdal, also target serotonin and have fewer side effects, but challenges remain in patient adherence and long-term symptom management. Combining medication with psychotherapy and skill-building therapies improves outcomes, emphasizing the importance of holistic care.
Drug therapies, while pivotal in psychiatric treatment, require personalized and cautious administration. Side effects, risk of dependency, and adherence issues necessitate a balanced approach, often integrating pharmacological interventions with psychotherapy for optimal results.

The development of psychotherapeutic drugs revolutionized mental healthcare, offering effective treatments for anxiety, mood disorders, and 
...

Treatment Strategies for Psychological Disorders

Treatment approaches for psychological disorders fall into three main categories: psychological, biological, and sociocultural. Each approach targets different aspects of mental health, requiring varying levels of education and training.
Psychological therapies focus on modifying emotions, thoughts, and behaviors through talking, interpreting, listening, rewarding, challenging, and modeling. Clinical psychologists, counselors, and social workers commonly practice psychotherapy. Clinical psychologists typically hold a Ph.D. or Psy.D., which involves years of graduate education, supervised clinical practice, and a clinical internship. Licensing and certification are two processes through which society regulates psychotherapy practitioners. Specific laws govern the requirements for obtaining a license or certification, ensuring that professionals meet specific educational and training standards. These regulations outline the necessary qualifications and mandate formal examinations to assess the practitioner&#39;s skills and competency before allowing them to practice.
Biological therapies, or biomedical therapies, aim to treat psychological disorders by altering physical body functions, often through medications. This approach views mental health disorders similarly to physical diseases, requiring medical intervention. Practitioners of biological therapies are generally medical doctors (MDs), with psychiatrists specializing in this field. Psychiatrists undergo medical school, residency, and specialized training in psychiatry. While both psychologists and psychiatrists can administer psychotherapy, only psychiatrists can prescribe medication. If medication is necessary, a psychotherapist may refer clients to a psychiatrist for prescriptions.
Sociocultural therapies emphasize the impact of social and cultural factors on mental health. This approach considers the individual&#39;s relationships, societal roles, and cultural influences in developing and treating psychological issues. Practitioners include psychotherapists, social workers, and psychiatric social workers, who are trained to intervene in the context of these social systems. Social workers typically hold a master&#39;s degree in social work (MSW), and psychiatric social workers receive additional training in mental health. Paraprofessionals, individuals without formal mental health qualifications but trained by professionals, can also assist, often bringing personal experience with specific disorders.

Treatment strategies for psychological disorders fall under three broad approaches - psychological, biological, and sociocultural.
The psychological ...

Psychotherapy

Psychotherapy is a versatile, nonmedical approach aimed at helping individuals address emotional, behavioral, and interpersonal issues to enhance their overall well-being. It can involve one-on-one sessions, couples counseling, or small group discussions with a therapist. The therapeutic process includes various techniques such as open discussion, interpretation of thoughts and behaviors, active listening, positive reinforcement, and role modeling. Psychotherapy aims to support individuals in understanding themselves better, whether or not they have diagnosed mental health conditions.
Insight Therapies
Insight therapies focus on uncovering the psychological motives behind behavior. By exploring unconscious processes, emotions, and past experiences, these therapies aim to help individuals better understand their actions and thought patterns. Psychodynamic therapy, based on Freud&#39;s psychoanalytic principles, delves into unresolved conflicts stemming from childhood. Humanistic therapy, developed by Carl Rogers, emphasizes personal growth and self-actualization, encouraging clients to explore their potential. Existential therapy addresses questions of meaning, freedom, and responsibility, while group therapy fosters interpersonal learning through shared experiences within a group setting.
Action Therapies
Action therapies, on the other hand, focus on modifying harmful thoughts and behaviors without delving deeply into their origins. Cognitive and cognitive-behavioral therapies (CBT) are the most widely used action therapies. Cognitive therapy helps individuals identify and challenge distorted or irrational thought patterns, while CBT combines this cognitive restructuring with behavioral techniques. The aim is to replace negative thought patterns with healthier, more adaptive ones and to encourage positive behavioral changes. These therapies are highly effective in treating conditions such as depression, anxiety disorders, and phobias.

Psychotherapy is a nonmedical approach designed to help individuals recognize and address emotional, behavioral, and interpersonal problems to improve ...

Elements Crucial for Effective Psychotherapy

Research has highlighted several critical factors that influence the effectiveness of psychotherapy, such as the therapeutic alliance, the therapist, and the client.
The Therapeutic Alliance
The therapeutic alliance refers to the relationship between the therapist and the client. The alliance strengthens when the therapist and the client engage in a nurturing, supportive, trusting, empathetic, and respectful relationship, improving therapeutic outcomes. Therapists must monitor this relationship continuously, as studies suggest that clients who rate the alliance poorly are more likely to discontinue therapy or have negative experiences. Conversely, those who share a strong bond with their therapist are more likely to see successful outcomes.
The Therapist
The effectiveness of psychotherapy can depend significantly on the therapist&#39;s skill set and expertise. Experienced therapists deeply understand psychological issues and are committed to adapting their approach based on ongoing progress. Research also suggests that the compatibility between the therapist&#39;s style and the client&#39;s personality plays a crucial role in therapy success. For example, a more flexible and laid-back therapist may succeed with a client who resists change, while a directive approach may work better for others.
The Client
Another major determinant of therapeutic outcomes is the client&#39;s role in the process. Meta-analyses suggest that the client&#39;s participation is one of the most critical factors in determining success. While clients often seek therapy for life challenges, their strengths, skills, and motivation largely contribute to their progress. Research has consistently shown that therapy&#39;s success depends significantly on the client&#39;s engagement, and clients who fail to participate actively are more likely to experience unsatisfactory results.

Effective psychotherapy depends on three crucial elements&#8212; the therapeutic alliance, the therapist, and the client.
The therapeutic alliance refers ...

Intellectual Disability

Intellectual disability (ID) is a neurodevelopmental condition characterized by deficits in intellectual and adaptive functioning that manifest during the developmental period. This condition encompasses challenges in reasoning, memory, problem-solving, and learning, accompanied by impairments in everyday life skills, such as communication, self-care, and social interactions. Intellectual disability affects approximately 1% of the population in the United States, impacting an estimated 5 million individuals.
Assessment and Diagnosis
Historically, the diagnosis of intellectual disability was heavily reliant on IQ scores, with an IQ below 70 considered a diagnostic threshold. However, recent standards, such as those outlined in the DSM-5, prioritize adaptive functioning over rigid IQ thresholds. Current assessments evaluate impairments across three domains: conceptual, social, and practical skills. Conceptual abilities include literacy, numeracy, and time management, while social skills cover empathy, interpersonal communication, and compliance with social norms. Practical skills pertain to personal care, job responsibilities, and daily routines.
Adaptive functioning is evaluated in the context of the individual&#39;s life circumstances. For example, two individuals with similar IQ scores might differ significantly in functionality &#8212; one might live independently with minimal support, while the other might require institutional care. This shift in diagnostic criteria emphasizes functional capabilities rather than test scores, allowing for a more nuanced understanding of intellectual disability.
Causes and Classifications
The etiology of intellectual disability can be organic or cultural-familial. Organic causes include genetic disorders, such as Down syndrome and Fragile X syndrome, and prenatal exposure to alcohol or toxins,&#160; which result in fetal alcohol syndrome. Fetal alcohol syndrome is a condition that results from exposing a developing embryo to alcohol, and intelligence levels can range from below average to levels associated with intellectual disability. Environmental factors, such as malnutrition, lack of stimulation, and inadequate healthcare, often underlie cultural-familial intellectual disability. This type of intellectual disability, with no identifiable physical damage, typically results in milder impairments.
Classifications range from mild to profound, based on the severity of deficits. Individuals with mild ID may achieve partial independence with support, while those with profound ID often remain fully dependent on caregivers due to severe limitations in all adaptive domains.
Holistic Perspectives
While intellectual disability affects cognitive and adaptive skills, it does not diminish the individual&#39;s capacity for forming meaningful relationships and contributing to their community. Understanding and addressing their diverse needs through tailored support and interventions can significantly enhance their quality of life and social integration.

Intellectual disability, previously termed as mental retardation, has been defined by significant cognitive deficits&#8212;which have been established ...

Conduct Disorder

Conduct disorder is a complex mental health diagnosis characterized by a repetitive and persistent pattern of behavior that violates societal norms, the rights of others, or age-appropriate rules. The diagnostic criteria for conduct disorder require the presence of at least three problematic behaviors within the past 12 months, with at least one occurring in the past six months. These behaviors are grouped into four categories: aggression toward people and animals; destruction of property; deceitfulness or theft; and serious violations of rules. The severity of symptoms, age of onset, and associated features all play crucial roles in understanding the disorder&#39;s impact and prognosis.
Diagnostic Features and Severity
The behaviors defining conduct disorder range from bullying, physical cruelty, and theft, to truancy and property destruction. Severity is categorized as mild, moderate, or severe, based on the number of symptoms and their impact on others. Childhood-onset conduct disorder, marked by symptoms before age 10, is associated with a poorer prognosis compared to adolescent-onset conduct disorder. Those with the specifier &#34;limited prosocial emotions&#34; &#8212; such as lack of remorse, callousness, or shallow affect &#8212; exhibit a more severe and persistent course.
Associated Factors and Risks
A combination of genetic, environmental, and temperamental factors influences conduct disorder. Risk factors include parental neglect, inconsistent discipline, exposure to violence, and association with delinquent peers. Neurobiological findings, such as reduced autonomic fear responses, and structural differences in brain regions associated with emotional regulation, have been observed but are not diagnostic. Co-occurring conditions, including ADHD, substance use disorders, and mood disorders, are common and can exacerbate the symptoms of conduct disorder.
Developmental Trajectory
Conduct disorder typically emerges during middle childhood or adolescence, often following oppositional defiant disorder. Symptoms evolve with age, beginning with less severe behaviors such as lying and escalating to more severe actions like theft and aggression. While the majority of cases remit by adulthood, childhood-onset conduct disorder is strongly predictive of antisocial personality disorder and other psychosocial difficulties later in life.
Sociocultural and Gender Considerations
The expression of conduct disorder behaviors differs by gender, with boys more likely to exhibit physical aggression and girls more often engaging in relational aggression or truancy. Cultural and environmental contexts, such as systemic oppression or high-crime areas, may influence the prevalence and manifestation of conduct disorder, necessitating careful diagnostic evaluation to avoid bias.
Conduct disorder presents significant challenges for affected individuals, families, and communities. Its association with academic failure, legal issues, and health risks underscores the importance of early intervention and comprehensive treatment approaches tailored to the individual&#39;s developmental and social context.

Conduct disorder involves a repetitive pattern of behavior violating others&#39; rights or societal norms, typically emerging in childhood or 
...

Learning Disabilities

Learning disabilities are cognitive disorders caused by neurological impairments that affect cognitive functions like language and reading, without indicating overall intellectual or developmental challenges. These disabilities differ from global intellectual or developmental disabilities as they are limited to distinct cognitive functions. Common learning disabilities include dysgraphia, dyslexia, and dyscalculia, each of which impacts unique aspects of learning.
<h4>Dyslexia</h4>
Dyslexia is a learning disability characterized by difficulties with reading fluency and comprehension despite normal intelligence. Individuals with dyslexia often struggle to decode and interpret written text. They may require additional time for reading and have difficulty associating letters with their corresponding sounds. Research has shown that dyslexia is independent of general cognitive ability, occurring across a broad spectrum of IQ levels.
<h4>Dysgraphia</h4>
Dysgraphia is marked by difficulty in writing legibly and coherently, making the physical act of writing a significant challenge. This impairment often contrasts with the individual&#39;s overall intellectual potential. Children with dysgraphia may struggle to translate their thoughts into written words and face spatial organization challenges, affecting handwriting consistency. These difficulties often require academic accommodations, such as assistive technologies or alternative assessment methods, to ensure success in educational settings.
<h4>Dyscalculia</h4>
Dyscalculia affects a child&#39;s ability to learn and understand arithmetic. Early signs include difficulty recognizing the quantity of small groups of objects without counting. Other challenges involve memorizing basic math facts, organizing numerical information, and distinguishing between numerical symbols and their verbal equivalents.

Learning disabilities are cognitive disorders caused by neurological impairments that affect cognitive functions like language and reading without ...

Personality Disorders: Dependent and Obsessive-Compulsive

Dependent personality disorder and obsessive-compulsive personality disorder are two separate psychological conditions that influence behavior, relationships, and overall life functioning. Though both involve maladaptive behaviors, their core characteristics and motivations differ significantly.
&#160;Dependent Personality Disorder
Dependent personality disorder is characterized by an excessive reliance on others to manage various aspects of life. Individuals with this disorder often struggle with decision-making, requiring constant reassurance and advice before making even minor choices. Their persistent fear of separation and abandonment leads them to exhibit submissive and clingy behaviors, as they prioritize maintaining relationships over asserting independence.
A key feature of dependent personality disorder is a profound lack of self-confidence, which contributes to feelings of helplessness when alone. Individuals with this disorder tend to perceive others as more competent and powerful while viewing themselves as childlike, weak, and incapable of functioning independently. This reliance on external support can lead them to tolerate mistreatment or remain in unhealthy relationships to avoid being alone.
Furthermore, their reluctance to take the initiative often results in an inability to complete tasks without assistance. They may avoid responsibilities that require self-sufficiency, preferring to defer to others for guidance. As a result, they may struggle in professional and personal settings where autonomy is needed.
Obsessive-Compulsive Personality Disorder
Obsessive-compulsive personality disorder is characterized by a pervasive preoccupation with perfectionism, order, and control, often at the expense of task completion, relationships, and overall well-being. Individuals with this disorder are excessively focused on details, rules, and schedules, hindering productivity as they struggle to overcome minor imperfections. Their rigid adherence to structure and standards often leads to inefficiency, as they prioritize precision over practicality.
A defining feature of obsessive-compulsive personality disorder is an intense devotion to work and productivity, often at the expense of leisure activities and personal relationships. These individuals may neglect social interactions and relaxation, believing that time not spent on work or structured tasks is wasted. Their inflexible mindset makes it difficult for them to delegate tasks, as they insist that things be done precisely their way. This insistence on control can strain professional and personal relationships, as they impose strict expectations on themselves and others.
Furthermore, individuals with this disorder tend to exhibit a rigid and stubborn disposition, resisting changes or alternative approaches. Their perfectionistic tendencies extend to financial habits, often manifesting as excessive frugality. They may be reluctant to spend money, even on necessities, due to an ingrained need for control and order in all aspects of life.

Dependent personality disorder is characterized by an excessive reliance on others to meet emotional and physical needs.
Individuals with this disorder ...

Testing the Heat Transfer Efficiency of a Finned-tube Heat Exchanger

Source: Michael G. Benton and Kerry M. Dooley, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Heat exchangers transfer heat from one fluid to another fluid. Multiple classes of heat exchangers exist to fill different needs. Some of the most common types are shell and tube exchangers and plate exchangers1. Shell and tube heat exchangers use a system of tubes through which fluid flows1. One set of tubes contains the liquid to be cooled or heated, while the second set contains the liquid that will either absorb heat or transmit it1. Plate heat exchangers use a similar concept, in which plates are closely joined together with a small gap between each for liquid to flow1. The fluid flowing between the plates alternates between hot and cold so that heat will move into or out of the necessary streams1. These exchangers have large surface areas, so they are usually more efficient1.
The goal for this experiment is to test the heat transfer efficiency of a finned-tube heat exchanger (Figure 1) and compare it to the theoretical efficiency of a heat exchanger without fins. The experimental data will be measured for three different flow rates of monoethylene glycol (MEG). Two different water flow rates for each MEG flow rate will be used. Using the Wilson plot method the heat transfer coefficients will be determined from the experimental data. Additionally, the Reynold&#39;s number and the amount of heat transferred will be compared for flow with and without the fins to evaluate heat transfer efficiency.
<img alt="Figure 1" src="/files/ftp_upload/10437/10437fig1.jpg" /> 
Figure 1: Finned-tube Heat Exchanger. 1) MEG outlet temperature 2) water inlet temperature 3) MEG inlet temperature 4) water outlet temperature 5) water meter 6) MEG accumulation sight glass/cylinder.

Heat Transfer Efficiency Test of a Finned-tube Heat Exchanger

Prueba de la eficiencia de transferencia de calor de un intercambiador de calor de tubos con aletas

Source: Michael G. Benton and Kerry M. Dooley, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Heat exchangers transfer ...

Using a Tray Dryer to Investigate Convective and Conductive Heat Transfer

Source: Michael G. Benton and <a href="https://www.jove.com/author/Kerry+M._Dooley">Kerry M. Dooley</a>, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Dryers are utilized in numerous industrial processes. The function of a dryer is to use heat transfer processes to dry solids. A variety of dryer types exist. Adiabatic dryers use convection and direct contact with gases to dry solids, whereas non-adiabatic dryers use methods other than heated gas contact to dry1, including conduction, radiation, and radio frequency drying1. Dryers can be used for batch processes or they be in continuous use1.
In this experiment, the effects of temperature and air velocity on the drying rate of sand will be determined using a tray dryer. Three different power settings (1000 W, 1500 W and 2500 W) for two different air flow rates will be tested, providing a total of six data sets. From this data, the heat and mass transfer coefficients can be calculated.

Tray Dryer Test to Investigate Convective and Conductive Heat Transfer

Uso de una bandeja de secado para investigar la transferencia de calor convectiva y conductiva

Source: Michael G. Benton and Kerry M. Dooley, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Dryers are utilized in ...

Viscosity of Propylene Glycol Solutions

Source: Michael G. Benton and <a href="https://www.jove.com/author/Kerry+M._Dooley">Kerry M. Dooley</a>, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Viscosity is a measure of a fluid&#39;s resistance to flow, and it is a useful parameter in the design of efficient product processing and quality control in a wide range of industries. A variety of viscometers are used to obtain the most accurate readings of experimental materials. The standard method of measuring viscosity is through a glass tube viscometer, which estimates viscosity by measuring the amount of time it takes fluid to flow through a capillary tube made of glass1.
Rotational viscometers operate by applying shearing forces and measuring the time it takes a flowing1. These viscometers make use of the flowing force of the fluid, and they can use either a spring system or a digital encoder system1. Different measuring systems exist as well, with the standard being a cone and plate system, where fluid flows under the cone shape and over the plate, in order to minimize shear stress1. Parallel plate systems use two parallel plates and is ideal for measuring across temperature gradients, allowing a smooth transition1. Couette systems use a cup and filling material, and the fluid flows in between the two1. These systems are best for materials with low viscosity, since this system minimizes shear stress, but the system is also harder to operate routinely due to issues with cleaning and needing larger volumes of fluid1.
In this experiment, a Cannon-Fenske viscometer will be used to measure the viscosities of several propylene glycol solutions to determine the relationship between viscosity and composition.

Measuring Viscosity of Propylene Glycol Solution Using a Glasstube Viscometer

Viscosidad de las soluciones de propilenglicol

Source: Michael G. Benton and Kerry M. Dooley, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Viscosity is a measure of a ...

Porosimetry of a Silica Alumina Powder

Source: <a href="https://www.jove.com/author/Kerry+M._Dooley">Kerry M. Dooley</a> and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Surface area and pore size distribution are attributes used by adsorbent and catalyst manufacturers and users to ensure quality control and to determine when products are at the end of their useful lives. The surface area of a porous solid is directly related to its adsorption capacity or catalytic activity. The pore size distribution of an adsorbent or catalyst is controlled such that pores are large enough to easily admit molecules of interest, but small enough to provide a high surface area per mass.
Surface area and pore size distribution can be measured by the technique of isothermal nitrogen adsorption/desorption. In this experiment, a nitrogen porosimeter will be used to measure the surface area and pore size distribution of a silica/alumina powder.

Measuring Porosimetry of Silica Alumina Powder Using a Nitrogen Porosimeter

Porosimetría de un polvo de alúmina de sílice

Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Surface area and pore size ...

Demonstration of the Power Law Model Through Extrusion

Source: <a href="https://www.jove.com/author/Kerry+M._Dooley">Kerry M. Dooley</a> and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Polymer melts are often formed into simple shapes or &#34;extrudates&#34;, such as cylindrical pellets, flat sheets, or pipe, using an extruder.1 Polyolefins are among the most common extrudable polymers. Extrusion involves transporting and melting solid feed, which is sometimes mixed with non-polymeric materials, and the pressure build-up and transport of the melt or mixture. It is applied to thermoplastic polymers, which deform when heated and resume their earlier &#34;no-flow&#34; properties when cooled.
Using a simple lab extruder, the effect of operating conditions on polymer output and pressure drop can be examined and the resulting data can be correlated using the &#34;Power Law&#34; model for flow of polymer melts and solutions. This model is used to scale up the process to more complex extruders. The relationship between operating conditions and the deviations from theoretical displacement behavior (&#34;slippage&#34;) and extrudate shape (&#34;die swell&#34;) can be determined.
In this experiment, a typical thermoplastic polymer, such as a high-density polyethylene (HDPE) copolymer (of ethylene + a longer chain olefin) will be used. The operating temperature for the die and zones depend on the material. The flow rate can be determined by weighing the die output at timed intervals. All other necessary data (screw speed, zone temperatures, pressure entering the die) can be read from the instrument panel.

Power Law Model Through Extrusion, Start-up and Heat-soak

Demostración del modelo de ley de energía a través de extrusión

Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Polymer melts are often ...

Gas Absorber

Source: Michael G. Benton and <a href="https://www.jove.com/author/Kerry+M._Dooley">Kerry M. Dooley</a>, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Gas absorbers are used to remove contaminants from gas streams. Multiple designs are used to accomplish this objective1. A packed bed column uses gas and liquid streams running counter to each other in a column packed with loose packing materials, such as ceramics, metals, and plastics, or structured packing1. The packed bed uses surface area created by the packing to create a maximum amount of efficient contact between the two phases1. The systems are low maintenance and can handle corrosive materials with high mass transfer rates1. Spray columns are another type of absorber, which uses constant direct contact between the two phases, with gas moving up and liquid being sprayed down into the gas flow1. This system only has one stage and poor mass transfer rates, but is very effective for solutes with high liquid solubility1.
The goal of this experiment is to determine how variables including gas flow rate, water flow rate, and carbon dioxide concentration affect the overall mass transfer coefficient in a gas absorber. Understanding how these parameters affect CO2 removal enables contaminant removal to be optimized. The experiment uses a randomly packed water counter-flow gas absorption column. Eight runs with two different gas flow rates, liquid flow rates, and CO2 concentrations were used. During each run, the partial pressures were taken from the bottom, middle, and top of the column unit, and the equilibrium partial pressures were calculated. These pressures were then used to find the mass transfer coefficient, and the mass transfer coefficients were compared to theoretical values.

Gas Absorber, Variable Flow Rate and Mass Transfer Coefficient

Amortiguador de gas

Source: Michael G. Benton and Kerry M. Dooley, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Gas absorbers are used to ...

Vapor-liquid Equilibrium

Source: Michael G. Benton and <a href="https://www.jove.com/author/Kerry+M._Dooley">Kerry M. Dooley</a>, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Vapor-liquid equilibrium is paramount in engineering applications such as distillation, environmental modeling, and general process design. Understanding the interactions of components in a mixture is very important in designing, operating and analyzing such separators. The activity coefficient is an excellent tool for relating molecular interactions to mixture composition. Finding the molecular interaction parameters allows future prediction of the activity coefficients for a mixture using a model.
Vapor-liquid equilibrium is a critical factor in common processes in the chemical industry, such as distillation. Distillation is the process of separating liquids by their boiling point. A liquid mixture is fed into a distillation unit or column, then boiled. Vapor-liquid equilibrium data is useful for determining how liquid mixtures will separate. Because the liquids have different boiling points, one liquid will boil into a vapor and rise in the column, while the other will stay as a liquid and drain through the unit. The process is very important in a variety of industries.
In this experiment, the activity coefficients of mixtures of various compositions of methanol, isopropanol, and deionized water will be obtained using a vapor-liquid equilibrium apparatus and gas chromatograph. Additionally, the binary interaction parameters of the system will be determined using Wilson&#39;s equation and the activity coefficients.

Vapor-liquid Equilibrium, Activity Coefficient, Fugacity

Equilibrio vapor-líquido

Source: Michael G. Benton and Kerry M. Dooley, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Vapor-liquid equilibrium is ...

The Effect of Reflux Ratio on Tray Distillation Efficiency

Source: <a href="https://www.jove.com/author/Kerry+M._Dooley">Kerry M. Dooley</a> and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Tray and packed columns are both commonly used for distillation, absorption, and stripping separation operations.1,2 The goal of this experiment is to distill a mixture of alcohols (methanol, isopropanol) and water in a sieve tray column and examine how closely simple theories of distillation based on equilibrium assumptions are followed. Sieve trays provide maximum interfacial area between the liquid and vapor. A P&#38;ID schematic of the sieve tray (each tray contains holes in a support plate) distillation system can be found in Appendix A.
In this demonstration, the Tray Distillation Unit (TDU) is started in total reflux mode. After a steady reflux drum level is attained, a switch to finite reflux mode is made by adjusting the bottoms, distillate and reflux flow rate controllers as necessary to maintain steady levels in the reflux drum and the reboiler, and to maintain a target reflux ratio RD = L/D. Once steady state is achieved (takes at least 90 min), liquid samples will be taken from the reflux drum, reboiler and on each tray and analyzed in a gas chromatograph. A typical protocol is to investigate the effects of reflux ratio over a wide range. From the sample analyses, the tray efficiencies can be determined for all three components on all six trays assuming constant molar overflow (McCabe-Thiele method). The results can also be simulated using an equilibrium process simulator, if available. These two methods can also be used to determine the overall tray efficiency. Additionally, data reconciliation of the mass balances can be performed to determine if gross measurement errors exist. Any Separations or Unit Operations textbook covers the fundamentals of distillation including basic concepts such as reflux ratio, Murphree efficiencies and the McCabe-Thiele method and diagram.2

Distillation Column Operation and Effects of Reflux Ratio

El efecto de la relación de reflujo en la eficiencia de destilación de bandeja

Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Tray and packed columns are ...

Efficiency of Liquid-liquid Extraction

Source: <a href="https://www.jove.com/author/Kerry+M._Dooley">Kerry M. Dooley</a> and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Liquid-liquid extraction (LLE) is a separation technique used instead of distillation when either: (a) the relative volatilities of the compounds to be separated are very similar; (b) one or more of the mixture components are temperature sensitive even near ambient conditions; (c) the distillation would require a very low pressure or a very high distillate/feed ratio.1The driving force for mass transfer is the difference in solubility of one material (the solute) in two other immiscible or partially miscible streams (the feed and the solvent). The feed and solvent streams are mixed and then separated, allowing the solute to transfer from the feed to the solvent. Normally, this process is repeated in successive stages using counter-current flow. The solute-rich solvent is called the extract as it leaves, and the solute-depleted feed is the raffinate. When there is a reasonable density difference between the feed and solvent streams, extraction can be accomplished using a vertical column, although in other cases a series of mixing and settling tanks may be used.
In this experiment, the operational goal is to extract isopropanol (IPA, ~10 - 15 wt. %, the solute) from a mixture of C8-to-C10 hydrocarbons using pure water as solvent. A York-Scheibel type (vertical mixers and coalescers, one each per physical stage) extraction column is available. Like most extractors, the overall efficiency (number theoretical stages/physical stages) of this column is quite low, especially in comparison to many distillation columns. The low efficiencies arise from both slow mass transfer (two liquid resistances instead of one as in distillation) and often also from maldistribution of the phases. The effect of agitator speed on both the solute recovery in the extract and the overall column efficiency will be evaluated.

Liquid-liquid Extraction and York-Scheibel Column Operation

Eficiencia de la extracción líquido-líquido

Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Liquid-liquid extraction ...

Liquid Phase Reactor: Sucrose Inversion

Source: <a href="https://www.jove.com/author/Kerry+M._Dooley">Kerry M. Dooley</a> and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Both batch and continuous flow reactors are used in catalytic reactions. Packed beds, which use solid catalysts and a continuous flow, are the most common configuration. In the absence of an extensive recycle stream, such packed bed reactors are typically modeled as &#34;plug flow&#34;. The other most common continuous reactor is a stirred tank, which is assumed to be perfectly mixed.1 One reason for the prevalence of packed bed reactors is that, unlike most stirred tank designs, a large wall area to reactor volume ratio promotes more rapid heat transfer. For almost all reactors, heat must either be added or withdrawn to control the temperature for the desired reaction to take place.
The kinetics of catalytic reactions are often more complex than the simple 1st order, 2nd order, etc. kinetics found in textbooks. The reaction rates can also be affected by rates of mass transfer - reaction cannot take place faster than the rate at which reactants are supplied to the surface or the rate at which products are removed - and heat transfer. For these reasons, experimentation is almost always necessary to determine the reaction kinetics prior to designing large-scale equipment. In this experiment, we explore how to conduct such experiments and how to interpret them by finding a reaction rate expression and an apparent rate constant.
This experiment explores the use of a packed bed reactor to determine the kinetics of sucrose inversion. This reaction is typical of those characterized by a solid catalyst with liquid phase reactants and products.
sucrose&#160;&#8594; glucose (dextrose) + fructose(1)
A packed bed reactor will be operated at different flow rates to control the space time, which is related to residence time and is analogous to elapsed time in a batch reactor. The catalyst, a solid acid, will first be prepped by exchanging protons for any other cations present. Then, the reactor will be heated to the desired temperature (isothermal operation) with the flow of reactants. When the temperature has equilibrated, product sampling will begin. The samples will be analyzed by a polarimeter, which measures optical rotation. The mixture&#39;s optical rotation can be related to the conversion of sucrose, which can then be used in standard kinetics analyses to determine the order of the reaction, with respect to the reactant sucrose, and the apparent rate constant. The effects of fluid mechanics - no axial mixing (plug flow) vs. some axial mixing (stirred tanks in series) - on the kinetics will be analyzed as well.

Reaction Kinetics in Packed Bed Reactor and Sucrose Inversion

Reactor de fase líquida: Inversión de sacarosa

Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Both batch and continuous ...

Crystallization of Salicylic Acid via Chemical Modification

Source: <a href="https://www.jove.com/author/Kerry+M._Dooley">Kerry M. Dooley</a> and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Processing of biochemicals involves unit operations such as crystallization, ultracentrifugation, membrane filtration, and preparative chromatography, all of which have in common the need to separate large from small molecules, or solid from liquid. Of these, crystallization is the most important from a tonnage standpoint. For that reason, it is commonly employed in the pharmaceutical, chemical and food processing industries. Important biochemical examples include chiral separations,1 purification of antibiotics,2 separation of amino acids from precursors,3 and many other pharmaceutical,4-5 food additive,6-7 and agrochemical purifications.8 The control of crystal morphology and size distribution is critical to process economics, as these factors affect the costs of downstream processing operations such as drying, filtration, and solids conveying. For more information about crystallization, consult a specialized textbook or a Unit Operations textbook.9
The crystallizer unit (Figure 1) enables study of: (a) the effects of key parameters, such as supersaturation and cooling/heating rates, on solids content, morphology and crystal size distribution; (b) and the on-line control of crystallization processes. Supersaturation can be controlled by altering conditions such as agitation rate and temperature. The different classifications of crystallization include cooling, evaporative, pH swing and chemical modification. In this experiment,an offline microscope will measure from crystals ranging in size from 10-1000 &#956;m, a typical size range for biologicals.
<img alt="Figure 1" src="/files/ftp_upload/10407/10407fig1.jpg" /> 
Figure 1: P&#38;ID schematic (left)and picture (right)of Crystallizer. <a href="//cloudfront.jove.com/files/ftp_upload/10407/10407fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
This experiment will demonstrate a &#34;chemical modification&#34;,or &#34;pH-swing&#34; crystallization, to generate salicylic acid (SAL) (precursor of aspirin) crystals from the rapid reaction of aqueous solutions of basic sodium salicylate (NaSAL), which are basic, and sulfuric acid (H2SO4) at anywhere from 40 - 80&#176;C.11
Na+SAL + 0.5 H2SO4 SAL (ppt) + Na+ + 0.5 SO42-
The byproduct sodium sulfate remains soluble. The apparatus consists of two feed tanks, three variable speed (peristaltic) pumps, the crystallizer (stirred tank to approximate uniform temperature and concentration, ~5 L), a circulating bath for temperature control, power controller, product tank, and a makeup tank for feed regeneration with NaOH solution (if desired). Samples will be analyzed by a UV-Vis spectrometer for the residual soluble salicylate ion, and the salicylic acid crystal product will be dried and weighed.A pH probe can be used to determine steady-state when reaction conditions are altered.

Cristalización del ácido salicílico mediante modificación química

Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Processing of biochemicals ...

Single and Two-phase Flow in a Packed Bed Reactor

Source: <a href="https://www.jove.com/author/Kerry+M._Dooley">Kerry M. Dooley</a> and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
The goal of this experiment is to determine the magnitude of maldistribution in typical packed bed reactors in both single phase and two-phase (gas-liquid) flow and evaluate the effects of this maldistribution on pressure drop. The concepts of residence time distribution and dispersion are introduced through the use of tracers, and these concepts are related to physical maldistribution.
Channeling in a single-phase flow can occur along walls or by preferential flow through a larger portion of the bed cross-section. Channeling in two-phase flow can result from even more complex causes, and simple two-phase flow theories seldom predict pressure drops in packed beds. A design goal is always to minimize the extent of channeling by finding the optimal bed and particle diameters for the design flow rates and by packing a bed in a way to minimize settling. It is always important to quantify how much maldistribution might occur and to over-design the unit to account for its occurrence.
The permeameter apparatus measures pressure drop, &#916;P, and the concentration of tracer (dye) exiting horizontal packed beds of armored glass for either water, air, or two-phase flow (Figures 1 and 2). Water enters through a control valve and can be routed through manual valves to any of five beds (48&#34; long, 3&#34; I.D.) with different size glass bead dumped (random) packings. The pressure drop is measured using a pressure transmitter. The water flow is measured by a differential pressure (DP, orifice) transmitter and the air flow by a dry test meter (similar to a home gas meter). The dye sample is injected upstream by an automated sampling valve. The exit concentration of the dye from a bed is measured using a UV-Vis spectrometer. Residence time distributions are calculated from the tests and compared to the predictions of theories on dispersion in packed beds. Two-phase flow will be studied in bed 5, which contains the largest particles.
<img alt="Figure 1" src="/files/ftp_upload/10431/10431fig1.jpg" /> 
Figure 1: Process and instrumentation diagram of the apparatus.
<img alt="Figure 2" src="/files/ftp_upload/10431/10431fig2.jpg" /> 
Figure 2. 3-D rendering of the apparatus. Bed #1 is at the top, bed #5 at the bottom. The water control valve is on the left (red bonnet). The DP transmitter is at the top center (blue).

Flujo monofásico y bifásico en un reactor de lecho compacto

Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
The goal of this experiment ...

Kinetics of Addition Polymerization to Polydimethylsiloxane

Source: <a href="https://www.jove.com/author/Kerry+M._Dooley">Kerry M. Dooley</a> and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Polymers are molecules consisting of many repeating monomer units that are chemically bonded into long chains. They exhibit a broad range of physical properties, which are affected by their chemical structure, molecular weight and degree of polymerization. The polymer industry manufactures thousands of raw materials used in a broad variety of commercial products.1,2
The goal of this video is to perform an addition polymerization reaction and then evaluate the resulting product to understand how viscosity can be used to determine polymer molecular weight. Additionally, this experiment will investigate how molecular weight can be related to monomer conversion.

Synthesis of Polydimethylsiloxane via Addition Polymerization

Cinética de la polimerización por adición de polidimetilsiloxano

Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Polymers are molecules ...

Catalytic Reactor: Hydrogenation of Ethylene

Source: <a href="https://www.jove.com/author/Kerry+M._Dooley">Kerry M. Dooley</a> and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
The hydrogenation of ethylene (C2H4) to ethane (C2H6) has often been studied as a model reduction reaction in characterizing new metal catalysts.1-2 While supported nickel is not the most active metal catalyst for this reaction, it is active enough that reaction can take place at &#60; 200&#176;C.
The reaction typically involves adsorbed, dissociated hydrogen (H2) reacting with adsorbed ethylene. In other words, both hydrogen-atoms and ethylene molecules form bonds with a metal site (here denoted &#34;S&#34;). The strong bonding of ethylene with S weakens the double bond sufficiently to allow hydrogen atoms to add to ethylene, forming ethane, which is not adsorbed.
The purpose of this experiment is, first, to convert raw composition measurements to limiting reactant fractional conversions.3 These conversions can then be used in a plug-flow reactor (PFR) to fit the data to a standard power-law kinetics model by the &#34;Integral Method&#34;.3 A comparison of the experimental orders of reaction for both ethylene and hydrogen with the theoretical orders reveals in this case that the reaction is kinetically controlled rather than mass-transfer controlled.

Heterogeneous Catalytic Reactor and Hydrogenation of Ethylene

Reactor catalítico: Hidrogenación de etileno

Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
The hydrogenation of ...

Evaluating the Heat Transfer of a Spin-and-Chill

Source: Michael G. Benton and Kerry M. Dooley, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
The Spin-and-Chill uses heat transfer and fluid flow fundamentals to chill beverages from room temperature to 38 &#176;F in as little as 2 min. It would take a refrigerator approximately 240 min and an ice chest approximately 40 min to achieve an equivalent temperature change. This is accomplished Spin and Chill by spinning a can or bottle at up to 500 rpm, which creates little or no foaming.
In this experiment, the efficacy of spinning a cylinder (i.e., soda can) at high speeds to cool a soft drink will be evaluated. Operational parameters, such as rpm and spin time, will be varied to assess their effect on heat transfer, and the heat transfer coefficient will be calculated using a lumped parameter model.

Convective Spin-and-Chill Heat Transfer: Lumped Parameter Model

Spin y Chill

Source: Michael G. Benton and Kerry M. Dooley, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
The Spin-and-Chill uses ...

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