The authors acknowledge Daniel Palys for supplying Figure 12 and for his assistance in managing laboratory supplies.

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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+the+Oil+Compatibility+Model+to+Refinery+Streams.">Application of the Oil Compatibility Model to Refinery Streams.</a> Energy Fuels. 14 (1), 60-63 (2000).</li><li>Rahimi, P., Gentzis, T., Cott&#233;, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigation+of+the+Thermal+Behavior+and+Interaction+of+Venezuelan+Heavy+Oil+Fractions+Obtained+by+Ion-Exchange+Chromatography.">Investigation of the Thermal Behavior and Interaction of Venezuelan Heavy Oil Fractions Obtained by Ion-Exchange Chromatography.</a> Energy Fuels. 13 (3), 694-701 (1999).</li><li>Bagheri, S. R., Gray, M. R., McCaffrey, W. 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C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Depolarized+Light+Scattering+for+Study+of+Heavy+Oil+and+Mesophase+Formation+Mechanisms.">Depolarized Light Scattering for Study of Heavy Oil and Mesophase Formation Mechanisms.</a> Energy Fuels. 26 (9), 5408-5420 (2012).</li><li>Laborde-Boutet, C., Dinh, D., Bender, F., Medina, M., McCaffrey, W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+Situ+Observation+of+Fouling+Behavior+under+Thermal+Cracking+Conditions:+Hue,+Saturation+and+Intensity+Image+Analyses.">In Situ Observation of Fouling Behavior under Thermal Cracking Conditions: Hue, Saturation and Intensity Image Analyses.</a> Energy Fuels. 30, 3666-3675 (2016).</li><li>Dinh, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> In-Situ Observation of Heavy-Oil Cracking using Backscattering Optical Techniques. MSc Thesis. , (2015).</li><li>Rahimi, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigation+of+Coking+Propensity+of+Narrow+Cut+Fractions+from+Athabasca+Bitumen+Using+Hot-Stage+Microscopy.">Investigation of Coking Propensity of Narrow Cut Fractions from Athabasca Bitumen Using Hot-Stage Microscopy.</a> Energy Fuels. 12 (5), 1020-1030 (1998).</li><li>Hanbury, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Constructing+cylindrical+coordinate+colour+spaces.">Constructing cylindrical coordinate colour spaces.</a> Pattern Recognition Letters. 29 (4), 494-500 (2008).</li><li>Gonzalez, R. C., Woods, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Digital Image Processing, Third Edition. , (2008).</li><li>Wachtman, J. B., Maxwell, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strength+of+Synthetic+Single+Crystal+Sapphire+and+Ruby+as+a+Function+of+Temperature+and+Orientation.">Strength of Synthetic Single Crystal Sapphire and Ruby as a Function of Temperature and Orientation.</a> J. Am. Ceram. Soc. 42 (9), 432-433 (1959).</li><li>Kaye, G. W. C., Laby, T. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Tables of physical and chemical constants / originally compiled by G.W.C. Kaye and T.H. Laby ; now prepared under the direction of an editorial committee. , (1995).</li><li>Malitson, I. H., Dodge, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Refractive+Index+and+Birefringence+of+Synthetic+Sapphire.">Refractive Index and Birefringence of Synthetic Sapphire.</a> J. Opt. Soc. Am. 62 (11), 1405 (1972).</li><li>Buckley, J. S., Hirasaki, G. J., Liu, Y., Von Drasek, S., Wang, J. X., Gill, B. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Asphaltene+Precipitation+and+Solvent+Properties+of+Crude+Oils.">Asphaltene Precipitation and Solvent Properties of Crude Oils.</a> Pet. Sci. Technol. 16 (3-4), 251-285 (1998).</li><li>Perrotta, A., McCullough, J. P., Beuther, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pressure-Temperature+Microscopy+of+Petroleum-Derived+Hydrocarbons.">Pressure-Temperature Microscopy of Petroleum-Derived Hydrocarbons.</a> Prepr. Pap. Am. Chem. Soc., Div. Pet. Chem. 28 (3), 633-639 (1983).</li></ol>

The authors have nothing to disclose.

צעדים קריטיים בתוך הפרוטוקול השלב הקריטי הראשון בפרוטוקול הוא הבטחה שלמות חותם מתכת אל-ספיר, במיוחד אם הניסוי הוא להתבצע תחת לחץ. לפיכך, ההקבלה, החלקלקות, ואת הניקיון של משטחי האיטום יש לבדוק בקפידה, ואת בדיקות הדליפה צריכות להיות ?...

המחקר של התנהגות השלב של דגימות שמנות במגוון רחב של טמפרטורות, לחצים, ותנאי תגובתי יכול להניב מידע שימושי מאוד עבור המפעיל של בית זיקוק שמעבדת מגוון של זנות. בפרט, העכירות של יחידות תהליך וקווים ידי היווצרות בלתי מבוקרת של קוק או משקעים יכולה להשפיע על ייצור קשה (אובדן התפוקה) וצריכת אנרגיה יעילה (גידול התנגדות העברת חום) 1, 2, 3. חיבור שנגרם אפשרי על ידי ההצטברות של עכירות חומר עשוי לדרוש כיבוי למטרות לנקות, אשר תהיה השפעה כלכלית שלילית מאוד 4. מבצע הערכה של נטיות עכירות של זנות יכולה להיות יקר מאוד עבור אופטימיזציה של תנאי תהליך 5 ואת המיזוג של זרמי זיקוק. פתחנו באתרומנתח של יציבות נפט במעבדה שלנו כדי לאפשר ההדמיה של דגימות שמן בכפוף לתנאי תהליך הזיקוק. מנגנון זה מסתמך על הכור תוכנן במיוחד עשוי אביזרי נירוסטה מצויד חלון ספיר אטום בתחתית. העיקרון המרכזי של המכשיר הוא הארת המדגם בתוך הכור על הטווח הרצוי של טמפרטורה והלחץ ואת ההדמיה של ההשתקפות הצולבת מקוטב שהתקבלה. בעוד מחקרים קודם שפורסמו בהשוואה להגדרה זו מתמקדת בתהליכי פירוק תרמיים לחקות תנאי visbreaking 6, 7, 8, 9 (אשר אינם דורשים בלחץ גבוה), עיצוב הכור עבר שינוי מקיף כדי לחקור את ההתנהגות של דגימות תחת hydroconversion (קטליטי פיצוח תחת H 2 בלחץ גבוה) ו aquathermal 10 (תרמית פיצוח תחת טרום גבוההקיטור ssure) תנאים. לכן, המכשיר תוקן על מנת לפעול בטווח 20-450 ° C הטמפרטורה ואת הטווח לחץ 0.1-16 MPa, עם היכולת לקיים הוא 450 ° C ו -16 מגפ&quot;ס עבור זמני תגובה של עד 6 שעות. הרמה הראשונה של ניתוח על המידע החזותי של הדגימות תחת טווח מסוים של טמפרטורה, לחץ, ותנאי תגובתי היא לקבוע אם המדגם הוא חד פאזיים או רב שלבית. מערכת זו היא ייחודית בכך שהיא מאפשרת ההדמיה של חומר איזוטרופי אטום אינו מוגבלת ההדמיה של חומר איזוטרופי המתואר עבודה אחרת 11. בעוד האינדיקטור המרכזי של הנטייה עכירות של דגימות היא הנטייה לרדת משקעים מתוך נוזלים בצובר; גז נוזלי, נוזל-נוזל, נוזל-מוצק, והתנהגויות שלב מורכבות יותר ניתן לצפות. עם זאת, מידע רב ערך יכול גם להיות הופק האבולוציה החזותית של נוזל כפי שהוא נשאר Homogeneous (חד פאזיים). בפרט, את הבהירות של תמונות קשורה מקדם השבירה ואת מקדם הכחדה של המדגם, בעוד הצבע של המדגם הוא קבוצת משנה של מידע ספקטרלי שלה בטווח האור הנראה (380-700 ננומטר), אשר יכול להיות משמש תאר הכימיה שלה 9.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Sapphire window, C-plane, 3mm thick - 20 mm diam., Scratch/Dig: 80/50</td>
			<td>Guild Optical Associates</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>C-seal</td>
			<td>American Seal &#38; Engineering</td>
			<td>31005</td>
			<td></td>
		</tr>
		<tr>
			<td>Type-K thermocouple</td>
			<td>Omega</td>
			<td>KMQXL-062U-9&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>Ferrule (1/16&#34;)</td>
			<td>Swagelok</td>
			<td>SS-103-1</td>
			<td>Inserted for creating a clearance gap between the magnet and the window surface</td>
		</tr>
		<tr>
			<td>Coil Heater</td>
			<td>OEM Heaters</td>
			<td>K002441</td>
			<td></td>
		</tr>
		<tr>
			<td>Temperature controller</td>
			<td>Omron</td>
			<td>E5CK</td>
			<td></td>
		</tr>
		<tr>
			<td>Inverted microscope</td>
			<td>Zeiss</td>
			<td>Axio Observer.D1m</td>
			<td>Require cross-polarizer module</td>
		</tr>
		<tr>
			<td>Toluene, 99.9% HPLC Grade</td>
			<td>Fisher</td>
			<td>Catalog # T290-4</td>
			<td>Harmful, to be handled in fume hood</td>
		</tr>
		<tr>
			<td>Methylene chloride, 99.9% HPLC Grade</td>
			<td>Fisher</td>
			<td>Catalog # D143-4</td>
			<td>Harmful, to be handled in fume hood</td>
		</tr>
		<tr>
			<td>Acetone, 99.7 Certified ACS Grade</td>
			<td>Fisher</td>
			<td>Catalog # A18P-4</td>
			<td></td>
		</tr>
	</tbody>
</table>

in situ visualization of the phase behavior of oil samples under refinery process conditions

To help address production issues in refineries caused by the fouling of process units and lines, we have developed a setup as well as a method to visualize the behavior of petroleum samples under process conditions. The experimental setup relies on a custom-built micro-reactor fitted with a sapphire window at the bottom, which is placed over the objective of an inverted microscope equipped with a cross-polarizer module. Using reflection microscopy enables the visualization of opaque samples, such as petroleum vacuum residues, or asphaltenes. The combination of the sapphire window from the micro-reactor with the cross-polarizer module of the microscope on the light path allows high-contrast imaging of isotropic and anisotropic media. While observations are carried out, the micro-reactor can be heated to the temperature range of cracking reactions (up to 450 &#176;C), can be subjected to H2 pressure relevant to hydroconversion reactions (up to 16 MPa), and can stir the sample by magnetic coupling. 
Observations are typically carried out by taking snapshots of the sample under cross-polarized light at regular time intervals. Image analyses may not only provide information on the temperature, pressure, and reactive conditions yielding phase separation, but may also give an estimate of the evolution of the chemical (absorption/reflection spectra) and physical (refractive index) properties of the sample before the onset of phase separation.

האבולוציה החזותית של שאריות אבק Athabasca היא נציג של ההתנהגות של דגימות נפט גולמי כבד asphaltenic ודוגמאות שאריות אבק asphaltenic בתנאי פיצוח תרמיים. עם זאת, באמצעות מדגמים שונים ו / או טמפרטורה שונה, לחץ, או תנאי תגובה יכול להצמיח מגוון רחב של התנהגויות שלב. Micrographs...

Watch this Scientific Journal Video about In Situ Visualization of the Phase Behavior of Oil Samples Under Refinery Process Conditions at JoVE.com

In Situ Visualization of the Phase Behavior of Oil Samples Under Refinery Process Conditions

This article describes a setup and method for the in situ visualization of oil samples under a variety of temperature and pressure conditions that aim to emulate refining and upgrading processes. It is primarily used for studying isotropic and anisotropic media involved in the fouling behavior of petroleum feeds.

באתרו ויזואליזציה של התנהגות השלב של דוגמאות שמן בתנאי תהליך זיקוק

To help address production issues in refineries caused by the fouling of process units and lines, we have developed a setup as well as a method to ...

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JoVE Journal

Engineering

In Situ Visualization of the Phase Behavior of Oil Samples Under Refinery Process Conditions

6.6K Views.  University of Alberta. This article describes a setup and method for the in situ visualization of oil samples under a variety of temperature and pressure conditions that aim to emulate refining and upgrading processes. It is primarily used for studying isotropic and anisotropic media involved in the fouling behavior of petroleum feeds.

Video: In Situ Visualization of the Phase Behavior of Oil Samples Under Refinery Process Conditions

Development of an Experimental Setup for the Measurement of the Coefficient of Restitution under Vacuum Conditions

The Discrete Element Method is used for the simulation of particulate systems to describe and analyze them, to predict and afterwards optimize their behavior for single stages of a process or even an entire process. For the simulation with occurring particle-particle and particle-wall contacts, the value of the coefficient of restitution is required. It can be determined experimentally. The coefficient of restitution depends on several parameters like the impact velocity. Especially for fine particles the impact velocity depends on the air pressure and under atmospheric pressure high impact velocities cannot be reached. For this, a new experimental setup for free-fall tests under vacuum conditions is developed. The coefficient of restitution is determined with the impact and rebound velocity which are detected by a high-speed camera. To not hinder the view, the vacuum chamber is made of glass. Also a new release mechanism to drop one single particle under vacuum conditions is constructed. Due to that, all properties of the particle can be characterized beforehand.

The coefficient of restitution is a parameter that describes the loss of kinetic energy during collision. Here, a free-fall setup under vacuum conditions is developed to be able to determine the coefficient of restitution parameter for particles in micrometer range with high impact velocities.

פיתוח של התקנה ניסיונית עבור המדידה של מקדם התקומה בתנאי אבק

The Discrete Element Method is used for the simulation of particulate systems to describe and analyze them, to predict and afterwards optimize their ...

Fabrication of White Light-emitting Electrochemical Cells with Stable Emission from Exciplexes

The authors present an approach for fabricating stable white light emission from polymer light-emitting electrochemical cells (PLECs) having an active layer which consists of blue-fluorescent poly(9,9-di-n-dodecylfluorenyl-2,7-diyl) (PFD) and &#960;-conjugated triphenylamine molecules. This white light emission originates from exciplexes formed between PFD and amines in electronically excited states. A device containing PFD, 4,4&#39;,4&#39;&#39;-tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA), Poly(ethylene oxide) and K2CF3SO3 showed white light emission with Commission internationale de l&#39;&#233;clairage (CIE) coordinates of (0.33, 0.43) and a Color Rendering Index (CRI) of Ra = 73 at an applied voltage of 3.5 V. Constant voltage measurements showed that the CIE coordinates of (0.27, 0.37), Ra of 67, and the emission color observed immediately after application of a voltage of 5 V were nearly unchanged and stable after 300 sec.

The authors present a method for fabricating stable white-light-emitting electrochemical cells utilizing emission from exciplexes formed between a blue-emitting fluorene polymer and aromatic amines.

המצאה של אור לבן פולטות תאים אלקטרוכימיים עם פליטה יציבה מ Exciplexes

The authors present an approach for fabricating stable white light emission from polymer light-emitting electrochemical cells (PLECs) having an active ...

Challenges in Rheological Characterization of Highly Concentrated Suspensions &#8212; A Case Study for Screen-printing Silver Pastes

A comprehensive rheological characterization of highly concentrated suspensions or pastes is mandatory for a targeted product development meeting the manifold requirements during processing and application of such complex fluids. In this investigation, measuring protocols for a conclusive assessment of different process relevant rheological parameters have been evaluated. This includes the determination of yield stress, viscosity, wall slip velocity, structural recovery after large deformation and elongation at break as well as tensile force during filament stretching.
The importance of concomitant video recordings during parallel-plate rotational rheometry for a significant determination of rheological quantities is demonstrated. The deformation profile and flow field at the sample edge can be determined using appropriate markers. Thus, measurement parameter settings and plate roughness values can be identified for which yield stress and viscosity measurements are possible. Slip velocity can be measured directly and measuring conditions at which plug flow, shear banding or sample spillover occur can be identified clearly. 
Video recordings further confirm that the change in shear moduli observed during three stage oscillatory shear tests with small deformation amplitude in stage I and III but large oscillation amplitude in stage II can be directly attributed to structural break down and recovery. For the pastes investigated here, the degree of irreversible, shear-induced structural change increases with increasing deformation amplitude in stage II until a saturation is reached at deformations corresponding to the crossover of G' and G'', but the irreversible damage is independent of the duration of large amplitude shear. 
A capillary breakup elongational rheometer and a tensile tester have been used to characterize deformation and breakup behavior of highly filled pastes in uniaxial elongation. Significant differences were observed in all experiments described above for two commercial screen-printing silver pastes used for front side metallization of Si-solar cells.

A protocol for a robust and application relevant rheological characterization of highly concentrated suspensions is presented. Silver pastes used for screen-printing application in solar cell production are employed as model systems.

אתגרים ראולוגיות אפיון השעיות מרוכזות מאוד - מקרה עבור משחות כסף הדפסת מסך

A comprehensive rheological characterization of highly concentrated suspensions or pastes is mandatory for a targeted product development meeting the ...

A Novel Biaxial Testing Apparatus for the Determination of Forming Limit under Hot Stamping Conditions

The hot stamping and cold die quenching process is increasingly used to form complex shaped structural components of sheet metals. Conventional experimental approaches, such as out-of-plane and in-plane tests, are not applicable to the determination of forming limits when heating and rapid cooling processes are introduced prior to forming for tests conducted under hot stamping conditions. A novel in-plane biaxial testing system was designed and used for the determination of forming limits of sheet metals at various strain paths, temperatures, and strain rates after heating and cooling processes in a resistance heating uniaxial testing machine. The core part of the biaxial testing system is a biaxial apparatus, which transfers a uniaxial force provided by the uniaxial testing machine to a biaxial force. One type of cruciform specimen was designed and verified for the formability test of aluminum alloy 6082 using the proposed biaxial testing system. The digital image correlation (DIC) system with a high-speed camera was used for taking strain measurements of a specimen during a deformation. The aim of proposing this biaxial testing system is to enable the forming limits of an alloy to be determined at various temperatures and strain rates under hot stamping conditions.

This protocol proposes a novel biaxial testing system used on a resistance heating uniaxial tensile test machine in order to determine the forming limit diagram (FLD) of sheet metals under hot stamping conditions.

מנגנון בדיקה חדשנית Biaxial לקביעת גבול יצירת תחת תנאי חם החתמת

The hot stamping and cold die quenching process is increasingly used to form complex shaped structural components of sheet metals. Conventional ...

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape method or individual WS2 nanotubes by dispersing the suspension of WS2 nanotubes. The selected samples have been fabricated into devices by the use of the electron beam lithography and electrolyte is put on the devices. We have characterized the electronic properties of the devices under applying the gate voltage. In the small gate voltage region, ions in the electrolyte are accumulated on the surface of the samples which leads to the large electric potential drop and resultant electrostatic carrier doping at the interface. Ambipolar transfer curve has been observed in this electrostatic doping region. When the gate voltage is further increased, we met another drastic increase of source-drain current which implies that ions are intercalated into layers of WS2 and electrochemical carrier doping is realized. In such electrochemical doping region, superconductivity has been observed. The focused technique provides a powerful strategy for achieving the electric-filed-induced quantum phase transition.

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

Here, we present a protocol to control the carrier number in solids by using the electrolyte.

פקד שדה חשמלי של הברית אלקטרונית ב- WS Nanodevices2 מאת אלקטרוליט Gating

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape ...

Predicting Catalyst Extrudate Breakage Based on the Modulus of Rupture

The mechanical strength of extruded catalysts and their natural or forced breakage by either collision against a surface or by a compressive load in a fixed bed are important phenomena in catalyst technology. The mechanical strength of the catalyst is measured here by its bending strength or flexural strength. This technique is relatively new from the perspective of applying it to commercial catalysts of typical sizes used in the industry. Catalyst breakage by collision against a surface is measured after a fall of the extrudates through the ambient air in a vertical pipe. Quantifying the impact force is done theoretically by applying Newton's second law. Measurement of catalyst breakage due to stress in a fixed bed is done following the standard procedure of the bulk crush strength test. Novel here is the focus on measuring the reduction in the length to diameter ratio of the extrudates as a function of the stress.

Here we present a protocol to measure the modulus of rupture of an extruded catalyst and the breakage of said catalyst extrudates by collision against a surface or by compression in a fixed bed.

שבירה Extrudate זרז נבואה על סמך המודולוס של קרע

The mechanical strength of extruded catalysts and their natural or forced breakage by either collision against a surface or by a compressive load in a ...

Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions

Two different experimental methods for determining the threshold of particle motion as a function of geometrical properties of the bed from laminar to turbulent flow conditions are presented. For that purpose, the incipient motion of a single bead is studied on regular substrates that consist of a monolayer of fixed spheres of uniform size that are regularly arranged in triangular and quadratic symmetries. The threshold is characterized by the critical Shields number. The criterion for the onset of motion is defined as the displacement from the original equilibrium position to the neighboring one. The displacement and the mode of motion are identified with an imaging system. The laminar flow is induced using a rotational rheometer with a parallel disk configuration. The shear Reynolds number remains below 1. The turbulent flow is induced in a low-speed wind tunnel with open jet test section. The air velocity is regulated with a frequency converter on the blower fan. The velocity profile is measured with a hot wire probe connected to a hot film anemometer. The shear Reynolds number ranges between 40 and 150. The logarithmic velocity law and the modified wall law presented by Rotta are used to infer the shear velocity from the experimental data. The latter is of special interest when the mobile bead is partially exposed to the turbulent flow in the so-called hydraulically transitional flow regime. The shear stress is estimated at onset of motion. Some illustrative results showing the strong impact of the angle of repose, and the exposure of the bead to shear flow are represented in both regimes.

Two different methods for characterizing the incipient particle motion of a single bead as a function of the sediment bed geometry from laminar to turbulent flow are presented.

באופן חזותי המבוסס על אפיון חלקיק התחלתית של סובסטרטים רגיל: מלמינריות לתנאים הסוערת

Two different experimental methods for determining the threshold of particle motion as a function of geometrical properties of the bed from laminar to ...

Experimental Procedure for Laboratory Studies of In Situ Burning : Flammability and Burning Efficiency of Crude Oil

A new method for the simultaneous study of the flammability and burning efficiency of fresh and weathered crude oil through two experimental laboratory setups is presented. The experiments are easily repeatable compared to operational scale experiments (pool diameter &#8805;2 m), while still featuring quite realistic in situ burning conditions of crude oil on water. Experimental conditions include a flowing water sub-layer that cools the oil slick and an external heat flux (up to 50 kW/m2) that simulates the higher heat feedback to the fuel surface in operational scale crude oil pool fires. These conditions enable a controlled laboratory study of the burning efficiency of crude oil pool fires that are equivalent to operational scale experiments. The method also provides quantitative data on the requirements for igniting crude oils in terms of the critical heat flux, ignition delay time as a function of the incident heat flux, the surface temperature upon ignition, and the thermal inertia. This type of data can be used to determine the required strength and duration of an ignition source to ignite a certain type of fresh or weathered crude oil. The main limitation of the method is that the cooling effect of the flowing water sub-layer on the burning crude oil as a function of the external heat flux has not been fully quantified. Experimental results clearly showed that the flowing water sub-layer does improve how representative this setup is of in situ burning conditions, but to what extent this representation is accurate is currently uncertain. The method nevertheless features the most realistic in situ burning laboratory conditions currently available for simultaneously studying the flammability and burning efficiency of crude oil on water.

Experimental Procedure for Laboratory Studies of In Situ Burning : Flammability and Burning Efficiency of Crude Oil

Here, we present a protocol to simultaneously study the flammability and burning efficiency of fresh and weathered crude oil under conditions that simulate in situ burning operations on the sea.

התהליך הניסיוני במחקרי מעבדה של בחיי עיר בוער: דליקות והיעילות צריבה של נפט גולמי

A new method for the simultaneous study of the flammability and burning efficiency of fresh and weathered crude oil through two experimental laboratory ...

Combining Microfluidics and Microrheology to Determine Rheological Properties of Soft Matter during Repeated Phase Transitions

The microstructure of soft matter directly impacts macroscopic rheological properties and can be changed by factors including colloidal rearrangement during previous phase changes and applied shear. To determine the extent of these changes, we have developed a microfluidic device that enables repeated phase transitions induced by exchange of the surrounding fluid and microrheological characterization while limiting shear on the sample. This technique is &#181;2rheology, the combination of microfluidics and microrheology. The microfluidic device is a two-layer design with symmetric inlet streams entering a sample chamber that traps the gel sample in place during fluid exchange. Suction can be applied far away from the sample chamber to pull fluids into the sample chamber. Material rheological properties are characterized using multiple particle tracking microrheology (MPT). In MPT, fluorescent probe particles are embedded into the material and the Brownian motion of the probes is recorded using video microscopy. The movement of the particles is tracked and the mean-squared displacement (MSD) is calculated. The MSD is related to macroscopic rheological properties, using the Generalized Stokes-Einstein Relation. The phase of the material is identified by comparison to the critical relaxation exponent, determined using time-cure superposition. Measurements of a fibrous colloidal gel illustrate the utility of the technique. This gel has a delicate structure that can be irreversibly changed when shear is applied. &#181;2rheology data shows that the material repeatedly equilibrates to the same rheological properties after each phase transition, indicating that phase transitions do not play a role in microstructural changes. To determine the role of shear, samples can be sheared prior to injection into our microfluidic device. &#181;2rheology is a widely applicable technique for the characterization of soft matter enabling the determination of rheological properties of delicate microstructures in a single sample during phase transitions in response to repeated changes in the surrounding environmental conditions.

We demonstrate the fabrication and use of a microfluidic device that enables multiple particle tracking microrheology measurements to study the rheological effects of repeated phase transitions on soft matter.

שילוב מיקרופלואידיקה Microrheology כדי לקבוע מאפייני Rheological מחומר רך במהלך שלב חוזרות מעברים

The microstructure of soft matter directly impacts macroscopic rheological properties and can be changed by factors including colloidal rearrangement ...

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

We demonstrate the use of two nuclear-based analytical methods that can follow the modifications of microstructural arrangement of iron-based metallic glasses (MGs). Despite their amorphous nature, the identification of hyperfine interactions unveils faint structural modifications. For this purpose, we have employed two techniques that utilize nuclear resonance among nuclear levels of a stable 57Fe isotope, namely M&#246;ssbauer spectrometry and nuclear forward scattering (NFS) of synchrotron radiation. The effects of heat treatment upon (Fe2.85Co1)77Mo8Cu1B14 MG are discussed using the results of ex situ and in situ experiments, respectively. As both methods are sensitive to hyperfine interactions, information on structural arrangement as well as on magnetic microstructure is readily available. M&#246;ssbauer spectrometry performed ex situ describes how the structural arrangement and magnetic microstructure appears at room temperature after the annealing under certain conditions (temperature, time), and thus this technique inspects steady states. On the other hand, NFS data are recorded in situ during dynamically changing temperature and NFS examines transient states. The use of both techniques provides complementary information. In general, they can be applied to any suitable system in which it is important to know its steady state but also transient states.

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

Here, we present a protocol to describe ex situ and in situ investigations of structural transformations in metallic glasses. We employed nuclear-based analytical methods which inspect hyperfine interactions. We demonstrate the applicability of M&#246;ssbauer spectrometry and nuclear forward scattering of synchrotron radiation during temperature-driven experiments.

שיטות של באתרו לשעבר בחיי עיר חקירות של המרות מבניים: המקרה של התגבשות של משקפיים מתכתי

We demonstrate the use of two nuclear-based analytical methods that can follow the modifications of microstructural arrangement of iron-based metallic ...