El autor correspondiente quisiera reconocer Consejo Nacional de Ciencia y Tecnología CONACYT del Gobierno Mexicano para la provisión de una beca.

NOTA: Las siguientes instrucciones son para el Protocolo A (Figura 1). Modificaciones para el Protocolo B, C, y D se enumeran también. 1. Barra de aluminio Preparación <ol><li> Coloque un pedazo grande (500 g - 1 kg) de lingote de aluminio de pureza comercial en un crisol. </li><li> Colocar el crisol en un horno a 800 ° C durante aproximadamente 1 hora, hasta que se funde. </li><li> Tome el crisol del horno y verter el aluminio fundido en un molde cilíndrico que es de 50 mm de diámetro, ligeramente menor que el diámetro final de la cámara para ser utilizados para la infiltración (51 mm), dando un espacio de aproximadamente ½ mm. </li><li> Espere 1 hora para la barra se enfríe. </li><li> Retire la barra del molde. </li><li> Con una sierra de banda, cortar en 4 trozos del mismo tamaño. </li><li> Lija los bordes de cada pieza para asegurar un buen ajuste en el molde de la infiltración. </li></ol> 2. Preparación del horno <ol><li> Programar el horno para llegar a un 740 &amp; #176; C meseta durante al menos 2 hr. </li><li> Ajustar la velocidad de calentamiento del horno a 20 ° C / min. </li></ol> 3. Preparación de preformas NOTA: Dependiendo de la altura de la espuma dirigido por, variar la cantidad de NaCl a utilizar para la infiltración entre 100 gy 300 g. <ol><li> Elige la infiltración NaCl de usar, con un diámetro que corresponde a la gama de tamaño de poro requerido (por ejemplo, un rango de entre 1,4 mm y 1,7 mm). El material se puede obtener de proveedores de productos químicos con alta pureza, o supermercado comprado la sal de mesa se puede utilizar (como material tendrá aditivos tales como agentes de yodo y anti-apelmazamiento, pero estos no hacer en la práctica el proceso de influencia en una medida significativa). </li><li> Seleccionar tamices de un intervalo de tamaño apropiado y apilar en un contenedor de base con el tamaño de abertura más pequeña en la parte inferior. </li><li> De la bolsa de NaCl de los proveedores, tardará aproximadamente 500 g y se vierte en los tamices apilados. </li><li> Agite los tamices, Ya sea manualmente o utilizando un agitador de tamices, durante 1 minuto. </li><li> Deseche el NaCl dejó en el mayor tamaño de la abertura del tamiz y el recipiente inferior, el NaCl queda en el tamiz de abertura menor se utiliza para la infiltración. </li><li> Pesar la cantidad de infiltración NaCl obtenido. </li><li> Si la cantidad es insuficiente, repita los pasos 03.04 a 03.07. NOTA: Para Protocolos B, C o D, obtener 100 g de NaCl fina (&lt;500 micras). Esto crea un espacio adicional en el molde para el aire atrapado en la preforma durante la infiltración en caso de que el aire en la preforma no escapa adecuadamente la cámara. </li></ol> Preparación 4. Molde <ol><li> El uso de papel de lija y rollo de papel de laboratorio, limpia el cilindro de molde (Figura 2), teniendo especial consideración, tanto para los bordes superior e inferior, y mantener el molde libre de cualquier impureza notables de usos anteriores. </li><li> Rociar el interior del cilindro de molde con pulverización de aerosol nitruro de boro, la creación de una cubierta de capa finael interior del molde. NOTA: Esto se logra cuando el color original del molde se sustituye por una capa blanca de la pulverización; no es necesario para medir su concentración específica. </li><li> Deje que el cilindro de molde seco durante al menos 5 minutos a temperatura ambiente (calentamiento a alrededor de 100 ° C durante un máximo de 1 hora se puede aplicar para el secado adicional si se desea). </li><li> El uso de papel de lija fino, eliminar cualquier residuo de nitruro de boro de los bordes del cilindro de molde, para mejorar el sello entre el cilindro de molde y la base del molde. NOTA: Los siguientes 3 pasos son para Protocolos A y B; Protocolos para C y D cortar sólo un anillo de junta de la tapa. </li><li> Cortar 2 anillos de juntas de 1 mm de espesor hoja de grafito (OD = 60 mm, ID = 51 mm), una para la unión entre el borde superior del cilindro de molde y la tapa del molde que conduce al sistema de válvula, y el otro para la unión entre el borde inferior del cilindro de molde y la base del molde. </li><li> Coloque una de las juntas en la ranura base del molde. </li><li> Coloque el bottom del cilindro de molde en la ranura con la junta. </li><li> Toque ligeramente con un mazo en la parte superior del cilindro de molde para asegurar la parte inferior de la ranura base. NOTA: Para Protocolo B, C o D, agregue el siguiente paso. <ol><li> Vierta la 100 g de NaCl fina (&lt;500 micras) en el cilindro de molde y aplanar la parte superior con una barra de aluminio sin cortar tocando la parte superior de la ligera con el mazo para garantizar la multa NaCl está lleno de una gran densidad. NOTA: Para Protocolo D Agregar el siguiente paso. </li><li> Cortar 2 círculos de 2 mm de espesor suave Kaowool cerámica cobija el tamaño del diámetro del molde (51 mm) y colocarlos en la parte superior de la multa NaCl, utilice la barra de aluminio sin cortar y el mazo para presionarlos contra la multa de NaCl. </li></ol></li><li> Vierta el NaCl que se infiltró en el cilindro del molde. NOTA: Para Protocolo D Agregar el siguiente paso. <ol><li> Coloque el molde y la base para una mesa vibratoria, asegurándose de que el cilindro del molde no se mueve de la ranura de la base. Vibrardurante 1 min a 50 Hz con una amplitud de 0,01 m. </li></ol></li><li> La celebración de la parte superior del cilindro en su lugar, recoger la base y agitar suavemente hasta que el NaCl en el interior del molde forma una superficie plana en la parte superior. </li><li> Coloque la barra de aluminio preparada en la parte superior de la preforma NaCl. </li><li> Colocar una junta de grafito en la ranura de la tapa del molde. </li><li> Por mano atornillar los 4 postes de acero inoxidable a la base y fijarlos con 4 conjuntos de tuercas de acero inoxidable y las arandelas en la parte superior de la base con una llave y coloque la tapa del molde en la parte superior del cilindro de molde a través de los montantes. </li><li> Con una llave de torsión fijado en 16 N · m, atornillar los 4 juegos de tuercas y arandelas de acero en las 4 varillas roscadas atornilladas en la base y que se extienden a través de la tapa, donde se aprietan las tuercas para fijar la tapa del molde en su lugar. </li><li> Coloque la parte superior de la tapa para el sistema de válvula con la junta, abrazadera, perno y la tuerca mariposa. </li><li> Cierre todas las válvulas del sistema. </li><li> Abra la válvula que lleva a tque la bomba de vacío y el molde (válvula 3). </li><li> Encienda la bomba de vacío hasta que el reloj de medición del sistema de válvula indica la menor presión posible. </li><li> Apague la bomba de vacío. </li><li> Si la pérdida de vacío en el sistema es inferior a una velocidad de 50 Torr / s para la primera 10 seg después de apagar la bomba de vacío el sello es suficientemente buena para la infiltración. </li><li> Deje la válvula de tapa abierta (válvula 3) para mantener el sistema a la presión ambiente y cerrar la válvula de la bomba de vacío (válvula 1). </li><li> Sin desconectar el sistema de la válvula, colocar el molde en el horno precalentado y esperar durante 1 hr. </li></ol> 5. Infiltración <ol><li> Cierre todas las válvulas del sistema (Figura 3). </li><li> Abrir la válvula que conduce al cilindro de gas argón (válvula 2). </li><li> Abra la válvula principal en el tanque de gas argón y ajustar la presión de la infiltración con la válvula del regulador (para un rango de 1,4 mm a 1,7 mm de tamaño de partícula NaCl, utilice una presión de 3,5 bares). NOTA: Para Protocolo B, se utiliza una presión de infiltración de 3 bar. Use una presión de 1 bar para Protocolos C y D. </li><li> De una manera rápida, abra la válvula de la tapa (válvula 3). </li><li> Después de 1 minuto, retirar el molde del horno y colóquelo en la parte superior de una superficie de enfriamiento (en este caso un bloque de cobre). NOTA: Mientras se enfría, la presión en el sistema cambiará. Para los primeros 5 minutos de este proceso, preste mucha atención a la presión indicada por el regulador y ajustar de nuevo a la presión de la infiltración de ser necesario. </li></ol> Extracción 6. Muestra <ol><li> Después de 30 minutos, cuando el molde se enfríe lo suficiente para manejar con guantes resistentes al calor luz, desconecte el sistema de la válvula y coloque la base del molde en un tornillo de banco banco de trabajo. Desenroscar la tapa de la parte superior del cilindro. </li><li> Con la tapa, golpee suavemente la parte superior del cilindro de molde con un mazo en una dirección perpendicular a las garras de la prensa de tornillo para aflojar el cilindro de molde de la ranura de la base. </li><li&gt; Quitar la base del molde de la prensa de tornillo y colocar el cilindro de molde en la tenaza. </li><li> Con el mazo de toque en el aluminio restante en la parte superior de la muestra para empujarlo fuera del cilindro de molde. </li><li> Usando una sierra de cinta, cortar la parte inferior de la muestra de espuma, la eliminación de los excedentes de aluminio. </li><li> Dependiendo de la altura de espuma necesario, corte, cuando se desee, cerca de la parte superior de la muestra. </li><li> Coloque la espuma infiltrado en un vaso de precipitados con agua y una barra de agitación magnética en una placa caliente de agitación para disolver la preforma NaCl. </li><li> Ajuste la temperatura de la placa caliente a 60 ° C. Cambie el agua cada 10 min hasta que no haya NaCl dejó en la espuma. NOTA: Para asegurar que no hay NaCl dejó en la espuma, cambiar el agua aproximadamente 10 veces. También es posible realizar controles periódicos de peso de la muestra después de una breve etapa de secado. Cuando esto deja de cambiar significativamente con más de inmersión, el NaCl debe ser completamente eliminado. </li><li> Finalmente utilizando un eléctricaaire más seco eliminar todo el agua que queda en la espuma. La muestra de espuma está listo. </li></ol>

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The authors declare that they have no competing financial interests.

El método básico descrito aquí se ha utilizado en diferentes formas por otros investigadores. Algunas de las variantes clave que permiten a las espumas de diferentes tipos que se creen se discuten. En la caracterización de estas espumas hemos medido la porosidad, ya que esta es una evaluación rápida y fácil de hacer, pero la caracterización de otras características estructurales, como el tamaño de poro, área superficial específica o grosor de los puntales pudieran requerirse para obtener una comprensión com...

A journal reference was corrected in the publication of <a href="http://www.jove.com/video/52268">Casting Protocols for the Production of Open Cell Aluminum Foams by the Replication Technique and the Effect on Porosity</a>. Reference 21 and 22 were originally merged together as one reference. They have been separated into references 21 and 22 in the article. The reference numbers have been updated in the article to reflect this additional reference citation. It has been updated from:
<ol start="21"><li>LeMay, J.D., Hopper, R.W., Hrubesh, L.W., &#38; Pekala, R.W. Low-Density Microcellular Materials. Materials Research Society Bulletin. 15 (12), 19&#8211;20 (1990).Seliger, H., &#38; Deuther U. Die Herstellung von Schaum- und Zellaluminium. Feiburger Forschungshefte. 103&#8211;129 (1965).</li></ol>
to:
<ol start="21"><li>LeMay, J.D., Hopper, R.W., Hrubesh, L.W., &#38; Pekala, R.W. Low-Density Microcellular Materials. Materials Research Society Bulletin. 15 (12), 19&#8211;20 (1990).</li>
<li>Seliger, H., &#38; Deuther U. Die Herstellung von Schaum- und Zellaluminium. Feiburger Forschungshefte. 103&#8211;129 (1965).</li></ol>

Erratum: Casting Protocols for the Production of Open Cell Aluminum Foams by the Replication Technique and the Effect on Porosity

Las espumas metálicas han atraído una gran cantidad de interés y el esfuerzo de investigación en los últimos años como lo demuestra la gran cantidad de trabajo citado en amplios artículos de revisión como Banhart 1, Conde et al. 2 o más recientemente Goodall y Mortensen 3. Entre los métodos utilizados para la producción del material, el proceso de replicación se distingue por su simplicidad experimental y el grado de control sobre la estructura de espuma final que se puede ofrecer. Cabe señalar que, aunque en la literatura tales materiales se describen a menudo como espumas (y son aquí) ya que no se producen por las burbujas de gas dentro de un líquido que se denominan más apropiadamente metales porosos o metales microcelulares. El primer informe del proceso de replicación era a principios del decenio de 1960 4, y se ha desarrollado aún más en las diferentes etapas, desde entonces, con notables avances por parte del grupo de investigación de Mortensen en la Escuela Polytechnique Federale de Lausanne en Suiza. El proceso se basa en la colada del metal alrededor de una preforma de partículas que define la forma de la porosidad en el material final 2, 5. Después de enfriar la preforma se puede eliminar por lixiviación disolvente o de pirólisis que provoca la oxidación. Un uso popular de esta técnica utiliza NaCl como titular de espacio para producir aluminio 5-10 o de aleación de aluminio espumas 11-14. NaCl tiene varias ventajas tales como ser fácilmente accesible, no tóxico y se puede retirar de la espuma por disolución en agua. Al tener un punto de fusión de 801 ° C, que puede ser utilizado con metales que tienen un punto inferior a este valor, más comúnmente fusión del aluminio, pero también existen ejemplos de la utilización con materiales tales como vidrios metálicos a granel, por humidificación una mezcla de aleación de vidrio metálico líquido a base de paladio y NaCl gránulos 15. La sustitución del NaCl con materiales de punto de fusión más alto también permite el production de espumas de metal de 16 puntos de mayor punto de fusión. Esto puede incluir otros materiales solubles en agua, o los insolubles incluyendo diferentes tipos de arena. En esta forma el proceso se vuelve más como el bastidor de arena convencional como para quitar la arena, chorros de agua de alta presión 17, 18 o diferentes formas de lavado de 19 o de agitación 20 son obligatorios. El proceso esencial 21 procede por tomar granos de NaCl y colocándolos en un molde 4, 22, 23. El método básico se ha utilizado para hacer de aluminio y aleación de aluminio espumas 24-26 para una amplia gama de investigaciones de comportamiento de la espuma. Los pasos adicionales se han introducido para controlar aún más la densidad y aumentar la interconectividad de los poros; éstos incluyen la densificación de la preforma. Para densificar la preforma, la sinterización se ha empleado 27, 28 y se ha utilizado en diferentes experimentos desde el 13, con el comportamiento de sinterización deNaCl sobre la base de la temperatura, tamaño de gránulo y la densidad descrito por Goodall et al. 29. Otro método utilizado para este propósito es prensado isostático en frío (CIP) 5, 30; esta es una técnica más rápida que se puede lograr un espectro más amplio de densidades comparables. El procedimiento también se puede realizar en el estado sólido con el polvo de metal y granos de NaCl, y entonces se llama a veces la sinterización y Disolución Proceso 31. Un estudio completo de la utilización de la técnica de la replicación hasta la fecha y la comparación con otras técnicas se da en Goodall y Mortensen 3. En este trabajo se reporta en detalle equipo y protocolos experimentales que se han utilizado para el procesamiento de espumas metálicas por el método de replicación, y que son relativamente fáciles de implementar en un entorno de laboratorio de investigación. Es importante reconocer que las otras variantes del equipo, con diferentes capacidades existen en otras investigaciones grupos, y que mientras el equipo que aquí se presenta es adecuado para procesar el material, no es la única versión o protocolo que puede ser hecho para trabajar. En cualquier caso, una comprensión completa de cualquier método en particular es esencial para el éxito experimental. Los protocolos precisos utilizados se detallan a continuación. Las variaciones de protocolo (A, B, C y D) tienen pequeños cambios entre ellos, destinado principalmente para alterar la densidad de las espumas producidas. La porosidad se ha calculado a partir de mediciones de la densidad aparente de las muestras, su volumen y la densidad del aluminio (2,7 g / cm 3). En el desarrollo de los métodos descritos para la producción de espuma de aluminio por la replicación, se han hecho intentos para reducir la cantidad de equipos avanzados para la más pequeña medida de lo posible, de tal manera que el método es tan fácil de implementar como sea posible. Otras variaciones que se pueden utilizar en las diferentes etapas se discuten más adelante.

<table border="0" cellpadding="0" cellspacing="0" width="1664">
	<tbody>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Name of Reagent/ Equipment</td>
			<td style="width:187px;">Company</td>
			<td style="width:429px;">Catalog Number</td>
			<td style="width:833px;">Comments/Description</td>
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			<td height="18" style="height:19px;width:216px;">Salt</td>
			<td style="width:187px;">Hydrosoft</td>
			<td style="width:429px;">Granular Salt 25 kg 855754</td>
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			<td height="18" style="height:19px;width:216px;">Aluminum</td>
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			<td style="width:429px;">Aluminum Ingots 99.87% pure 25 kg drum</td>
			<td>http://www.william-rowland.com/products/high-purity-metals#product-id-1</td>
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			<td>http://www.morganmms.com/crucibles-foundry-products/crucibles/syncarb/</td>
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			<td>http://www.elitefurnaces.com/eng/products/furnaces/1200%20Top%20Loading%20Furnaces.php</td>
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		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Bar Mold</td>
			<td style="width:187px;">The University of Sheffield</td>
			<td style="width:429px;">Custom Made</td>
			<td>Stainless Steel 304, 15 cm height, 5 cm inner diameter, 6 cm outer diameter</td>
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		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Band Saw</td>
			<td style="width:187px;">Clarke</td>
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			<td style="width:429px;">Specialist wet &#38; dry sandpaper 501885</td>
			<td>http://www.wickes.co.uk/Specialist-Wet+Dry-Sandpaper-PK4/p/501885</td>
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			<td style="width:187px;">Fisher Scientific</td>
			<td style="width:429px;">Fisherbrand test sieves 200 mm diamater</td>
			<td>http://www.fisher.co.uk/product/brand_listing.php/F/Fisherbrand/Sieve</td>
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			<td height="18" style="height:19px;width:216px;">Balance</td>
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			<td style="width:429px;">XB 6200C</td>
			<td>http://www.precisa.co.uk/precision_balances.php</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;width:216px;">Boron Nitride</td>
			<td style="width:187px;">Kennametal</td>
			<td style="width:429px;">500 ml spray can</td>
			<td style="width:833px;">http://www.kennametal.com/content/dam/kennametal/kennametal/common/Resources/Catalogs-Literature/Advanced%20Materials%20and%20Wear%20Components/B-13-03401_ceramic_powders 
			_brochure_EN.pdf</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Infiltration Mold, Base and Lid</td>
			<td style="width:187px;">The University of Sheffield</td>
			<td style="width:429px;">Custom Made</td>
			<td>Stainless Steel 304, 15 cm height, 5.1 cm inner diameter, 6 cm outer diameter</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Cylindrical Mold</td>
			<td style="width:187px;">The University of Sheffield</td>
			<td style="width:429px;">Custom Made</td>
			<td>Low carbon steel 1020, 15 cm height, 5 cm inner diameter, 6 cm outer diameter</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Graphite Gasket</td>
			<td style="width:187px;">Gee Graphite</td>
			<td style="width:429px;">Geegraf Stainless Steel Reinforced Graphite 1 mm thick</td>
			<td>http://www.geegraphite.com/steel_reinforced.html</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Mallet</td>
			<td style="width:187px;">Thor Hammer Co. Ltd.</td>
			<td style="width:429px;">Round Solid Super Plastic Mallet</td>
			<td>http://www.thorhammer.com/Mallets/Round/</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Wrench</td>
			<td style="width:187px;">Kennedy Professional</td>
			<td style="width:429px;">13 mm Ratchet Combination Wrench KEN5822166K</td>
			<td>https://www.cromwell.co.uk/KEN5822166K</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Nuts</td>
			<td style="width:187px;">Matlock</td>
			<td style="width:429px;">M8 Steel hex full nut galvanized</td>
			<td>https://www.cromwell.co.uk/CTL6400068J</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Washers</td>
			<td style="width:187px;">Matlock</td>
			<td style="width:429px;">M8 Form-A steel washer bzp</td>
			<td>https://www.cromwell.co.uk/CTL6451208H</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">SS Nuts</td>
			<td style="width:187px;">Matlock</td>
			<td style="width:429px;">M8 A2 st/st hex full nut</td>
			<td>https://www.cromwell.co.uk/CTL6423008F</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">SS Washers</td>
			<td style="width:187px;">Matlock</td>
			<td style="width:429px;">M8 A2 st/st Form-A washer</td>
			<td>https://www.cromwell.co.uk/CTL6464008H</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Stainless Steel Studding</td>
			<td style="width:187px;">Cromwell</td>
			<td style="width:429px;">M8 x 1 Mtr A2 Stainless Steel Studding QFT6397080K</td>
			<td>https://www.cromwell.co.uk/QFT6397080K</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Valves</td>
			<td style="width:187px;">Edwards</td>
			<td style="width:429px;">C33205000 SP16K, Nitrile Diaphragm</td>
			<td>https://www.edwardsvacuum.com/Products/View.aspx?sku=C33205000</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Fitting Cross</td>
			<td style="width:187px;">Edwards</td>
			<td style="width:429px;">C10512412 NW16 Cross Piece Aluminum</td>
			<td>https://www.edwardsvacuum.com/Products/C10512412/View.aspx</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Fitting T</td>
			<td style="width:187px;">Edwards</td>
			<td style="width:429px;">C10512411 NW16 T-Piece Aluminum</td>
			<td>https://www.edwardsvacuum.com/Products/C10512411/View.aspx</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Vacuum Pump</td>
			<td style="width:187px;">Edwards</td>
			<td style="width:429px;">A36310940 E2M18 200-230/380-415V,3-ph, 50Hz</td>
			<td>http://www.edwardsvacuum.com/Products/View.aspx?sku=A36310940</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Dial Gauge</td>
			<td style="width:187px;">Edwards</td>
			<td style="width:429px;">D35610000 CG16K, 0-1040mbar</td>
			<td>http://www.edwardsvacuum.com/Products/View.aspx?sku=D35610000</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Argon Gas</td>
			<td style="width:187px;">BOC</td>
			<td style="width:429px;">Pureshield Argon Gas</td>
			<td>http://www.boconline.co.uk/en/products-and-supply/industrial-gases/inert-gases/pureshield-argon/pureshield-argon.html</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Stainless Steel Hose</td>
			<td style="width:187px;">BOC</td>
			<td style="width:429px;">Stainless Steel Hose</td>
			<td>http://www.boconline.co.uk/en/products-and-supply/speciality-equipment/hoses-and-pigtails/index.html</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;width:216px;">Regulator</td>
			<td style="width:187px;">BOC</td>
			<td style="width:429px;">HP 1500 Series Regulator</td>
			<td style="width:833px;">http://www.boconline.co.uk/en/products-and-supply/speciality-equipment/regulators/single-stage-regulators/hp1500-series/hp1500-series.html</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Copper Block</td>
			<td style="width:187px;">William Rowland</td>
			<td style="width:429px;">Copper Ingot 25 kg</td>
			<td>http://www.william-rowland.com/products/high-purity-metals#product-id-18</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Vise</td>
			<td style="width:187px;">Record</td>
			<td style="width:429px;">T84-34 H/Duty Eng Vice 4 1/2&#34; Jaws REC5658326K</td>
			<td>https://www.cromwell.co.uk/REC5658326K</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;width:216px;">Beaker</td>
			<td style="width:187px;">Fisher Scientific</td>
			<td style="width:429px;">11567402 - Beaker, squat form, with graduations and spout 800mL</td>
			<td style="width:833px;">https://webshop.fishersci.com/insight2_uk/getProduct.do;jsessionid=16D5812 
			D71B8CB37B475E94281E2BEA 
			5.ukhigjavappp11?productCode=11567402&#38;resultSet 
			Position=0</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Stirring Hot Plate</td>
			<td style="width:187px;">Corning</td>
			<td style="width:429px;">Corning stirring hot plate Model 6798-420d</td>
			<td>http://www.corning.com/lifesciences/us_canada/en/technical_resources/product_guid/shp/shp.aspx</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;width:216px;">Stir Bar</td>
			<td style="width:187px;">Fisher Scientific</td>
			<td style="width:429px;">11848862 - PTFE Stir bar + Ring 25x6 mm</td>
			<td style="width:833px;">https://webshop.fishersci.com/insight2_uk/getProduct.do;jsessionid=16D5812 
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			Position=0</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Air dryer</td>
			<td style="width:187px;">V05</td>
			<td style="width:429px;">V05 Max Air Turbo Dryer DR-120-GB</td>
			<td>http://reviews.boots.com/2111-en_gb/1120627/v05-v05-max-air-turbo-hair-dryer-dr-120-gb-reviews/reviews.htm</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Ceramic Sheet</td>
			<td style="width:187px;">Morgan Advance Materials</td>
			<td style="width:429px;">Kaowool Blanket 2 mm thick</td>
			<td>http://www.morganthermalceramics.com/downloads/datasheets?f[0]=field_type%3A84</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Vibrating Table</td>
			<td style="width:187px;">Pevco</td>
			<td style="width:429px;">Pevco Vibrating Table 1.25m x 0.625m x 0.6m</td>
			<td>http://www.peverilmachinery.co.uk/equipment/vibrating-tables</td>
		</tr>
	</tbody>
</table>

casting protocols for the production of open cell aluminum foams by the replication technique and the effect on porosity

Las espumas metálicas son materiales interesantes, tanto de una comprensión fundamental y práctico punto de vista de las aplicaciones. Se han propuesto usos, y en muchos casos validado experimentalmente, para el peso de luz o de absorción de energía de impacto estructuras, como intercambiadores de calor de superficie alta área o electrodos, como implantes en el cuerpo, y muchos más. Aunque se han hecho grandes progresos en la comprensión de sus relaciones estructura-propiedades, la gran cantidad de diferentes técnicas de procesamiento, cada material produciendo con diferentes características y estructura, significa que la comprensión de los efectos individuales de todos los aspectos de la estructura no está completa. El proceso de replicación, donde se infiltra metal fundido entre los granos de un material de la preforma extraíble, permite una marcadamente alto grado de control y se ha utilizado con buenos resultados para dilucidar algunas de estas relaciones. Sin embargo, el proceso tiene muchos pasos que dependen individual &quot;know-how&quot;, yeste trabajo tiene como objetivo proporcionar una descripción detallada de todas las etapas de una realización de este método de procesamiento, el uso de materiales y equipos que serían relativamente fáciles de instalar en un entorno de investigación. El objetivo de este protocolo y sus variantes es producir espumas metálicas en una manera eficaz y simple, dando la posibilidad de adaptar el resultado de las muestras mediante la modificación de ciertas etapas dentro del proceso. Siguiendo esto, las espumas de celda abierta de aluminio con tamaños de poro de 1 a 2,36 mm de diámetro y 61% a 77% de porosidad se pueden obtener.

En la figura 4 la morfología de los granos de NaCl se puede ver (angular y esférica), con fines ilustrativos. Las espumas obtenidas con el Protocolo se hicieron utilizando granos de forma angular y el resto se hicieron con los granos esféricos. Se encontró que el uso de diferentes formas granos de NaCl no tuvo ningún efecto observado sobre la porosidad obtenida en las muestras. De los resultados podemos determinar que las muestras a, b, y c (hecho con Protocolo A), son ...

Watch this Scientific Journal Video about Casting Protocols for the Production of Open Cell Aluminum Foams by the Replication Technique and the Effect on Porosity at JoVE.com

Casting Protocols for the Production of Open Cell Aluminum Foams by the Replication Technique and the Effect on Porosity

Replication is one of the processing techniques used for the production of porous metal sponges. In this paper one implementation of the method for the production of open celled porous aluminum is shown in detail.

Casting Protocolos para la Producción de célula abierta de aluminio Espumas por la técnica de replicación y el efecto de la porosidad

Metal foams are interesting materials from both a fundamental understanding and practical applications point of view. Uses have been proposed, and in many ...

casting-protocols-for-production-open-cell-aluminum-foams-replication

Research

JoVE Journal

Engineering

14.4K vistas.  The University of Sheffield. Replication is one of the processing techniques used for the production of porous metal sponges. In this paper one implementation of the method for the production of open celled porous aluminum is shown in detail.

Video: Casting Protocols for the Production of Open Cell Aluminum Foams by the Replication Technique and the Effect on Porosity

Harvesting Solar Energy by Means of Charge-Separating Nanocrystals and Their Solids

Conjoining different semiconductor materials in a single nano-composite provides synthetic means for the development of novel optoelectronic materials offering a superior control over the spatial distribution of charge carriers across material interfaces. As this study demonstrates, a combination of donor-acceptor nanocrystal (NC) domains in a single nanoparticle can lead to the realization of efficient photocatalytic1-5 materials, while a layered assembly of donor- and acceptor-like nanocrystals films gives rise to photovoltaic materials.
Initially the paper focuses on the synthesis of composite inorganic nanocrystals, comprising linearly stacked ZnSe, CdS, and Pt domains, which jointly promote photoinduced charge separation. These structures are used in aqueous solutions for the photocatalysis of water under solar radiation, resulting in the production of H2 gas. To enhance the photoinduced separation of charges, a nanorod morphology with a linear gradient originating from an intrinsic electric field is used5. The inter-domain energetics are then optimized to drive photogenerated electrons toward the Pt catalytic site while expelling the holes to the surface of ZnSe domains for sacrificial regeneration (via methanol). Here we show that the only efficient way to produce hydrogen is to use electron-donating ligands to passivate the surface states by tuning the energy level alignment at the semiconductor-ligand interface. Stable and efficient reduction of water is allowed by these ligands due to the fact that they fill vacancies in the valence band of the semiconductor domain, preventing energetic holes from degrading it. Specifically, we show that the energy of the hole is transferred to the ligand moiety, leaving the semiconductor domain functional. This enables us to return the entire nanocrystal-ligand system to a functional state, when the ligands are degraded, by simply adding fresh ligands to the system4.
To promote a photovoltaic charge separation, we use a composite two-layer solid of PbS and TiO2 films. In this configuration, photoinduced electrons are injected into TiO2 and are subsequently picked up by an FTO electrode, while holes are channeled to a Au electrode via PbS layer6. To develop the latter we introduce a Semiconductor Matrix Encapsulated Nanocrystal Arrays (SMENA) strategy, which allows bonding PbS NCs into the surrounding matrix of CdS semiconductor. As a result, fabricated solids exhibit excellent thermal stability, attributed to the heteroepitaxial structure of nanocrystal-matrix interfaces, and show compelling light-harvesting performance in prototype solar cells7.

A general strategy for the development of charge-separating semiconductor nanocrystal composites deployable for solar energy production is presented. We show that assembly of donor-acceptor nanocrystal domains in a single nanoparticle geometry gives rise to a photocatalytic function, while bulk-heterojunctions of donor-acceptor nanocrystal films can be used for photovoltaic energy conversion.

Captación de energía solar por medio de carga de separación nanocristales y sus sólidos

Conjoining different semiconductor materials in a single nano-composite provides synthetic means for the development of novel optoelectronic materials ...

Investigación

Ingeniería

Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds

Monolayer Contact Doping (MLCD) is a simple method for doping of surfaces and nanostructures1. MLCD results in the formation of highly controlled, ultra shallow and sharp doping profiles at the nanometer scale. In MLCD process the dopant source is a monolayer containing dopant atoms.
In this article a detailed procedure for surface doping of silicon substrate as well as silicon nanowires is demonstrated. Phosphorus dopant source was formed using tetraethyl methylenediphosphonate monolayer on a silicon substrate. This monolayer containing substrate was brought to contact with a pristine intrinsic silicon target substrate and annealed while in contact. Sheet resistance of the target substrate was measured using 4 point probe. Intrinsic silicon nanowires were synthesized by chemical vapor deposition (CVD) process using a vapor-liquid-solid (VLS) mechanism; gold nanoparticles were used as catalyst for nanowire growth. The nanowires were suspended in ethanol by mild sonication. This suspension was used to dropcast the nanowires on silicon substrate with a silicon nitride dielectric top layer. These nanowires were doped with phosphorus in similar manner as used for the intrinsic silicon wafer. Standard photolithography process was used to fabricate metal electrodes for the formation of nanowire based field effect transistor (NW-FET). The electrical properties of a representative nanowire device were measured by a semiconductor device analyzer and a probe station.

A detailed procedure for surface doping of Silicon interfaces is provided. The ultra-shallow surface doping is demonstrated by using phosphorus containing monolayers and rapid annealing process. The method can be used for doping of macroscopic area surfaces as well as nanostructures.

Monolayer Contact Doping (MLCD) is a simple method for doping of surfaces and nanostructures1. MLCD results in the formation of highly controlled, ultra ...

Fast Imaging Technique to Study Drop Impact Dynamics of Non-Newtonian Fluids

In the field of fluid mechanics, many dynamical processes not only occur over a very short time interval but also require high spatial resolution for detailed observation, scenarios that make it challenging to observe with conventional imaging systems. One of these is the drop impact of liquids, which usually happens within one tenth of millisecond. To tackle this challenge, a fast imaging technique is introduced that combines a high-speed camera (capable of up to one million frames per second) with a macro lens with long working distance to bring the spatial resolution of the image down to 10 &#181;m/pixel. The imaging technique enables precise measurement of relevant fluid dynamic quantities, such as the flow field, the spreading distance and the splashing speed, from analysis of the recorded video. To demonstrate the capabilities of this visualization system, the impact dynamics when droplets of non-Newtonian fluids impinge on a flat hard surface are characterized. Two situations are considered: for oxidized liquid metal droplets we focus on the spreading behavior, and for densely packed suspensions we determine the onset of splashing. More generally, the combination of high temporal and spatial imaging resolution introduced here offers advantages for studying fast dynamics across a wide range of microscale phenomena.

Drop impact of non-Newtonian fluids is a complex process since different physical parameters influence the dynamics over a very short time (less than one tenth of a millisecond). A fast imaging technique is introduced in order to characterize the impact behaviors of different non-Newtonian fluids.

Técnica de escaneo rápido para el Estudio de impacto por caída de la Dinámica de Fluidos no newtonianos

In the field of fluid mechanics, many dynamical processes not only occur over a very short time interval but also require high spatial resolution for ...

Integrating a Triplet-triplet Annihilation Up-conversion System to Enhance Dye-sensitized Solar Cell Response to Sub-bandgap Light

The poor response of dye-sensitized solar cells (DSCs) to red and infrared light is a significant impediment to the realization of higher photocurrents and hence higher efficiencies. Photon up-conversion by way of triplet-triplet annihilation (TTA-UC) is an attractive technique for using these otherwise wasted low energy photons to produce photocurrent, while not interfering with the photoanodic performance in a deleterious manner. Further to this, TTA-UC has a number of features, distinct from other reported photon up-conversion technologies, which renders it particularly suitable for coupling with DSC technology. In this work, a proven high performance TTA-UC system, comprising a palladium porphyrin sensitizer and rubrene emitter, is combined with a high performance DSC (utilizing the organic dye D149) in an integrated device. The device shows an enhanced response to sub-bandgap light over the absorption range of the TTA-UC sub-unit resulting in the highest figure of merit for up-conversion assisted DSC performance to date.

An integrated device, incorporating a dye-sensitized solar cell and triplet-triplet annihilation up-conversion unit was produced, affording enhanced light harvesting, from a wider section of the solar spectrum. Under modest irradiation levels a significantly enhanced response to low energy photons was demonstrated, yielding a record figure of merit for dye-sensitized solar cells.

La integración de un Sistema de Up-conversión trío-triplete Aniquilación para Mejorar sensibilizado-Dye respuesta de células solares a la luz Sub-gap

The poor response of dye-sensitized solar cells (DSCs) to red and infrared light is a significant impediment to the realization of higher photocurrents ...

Ambient Method for the Production of an Ionically Gated Carbon Nanotube Common Cathode in Tandem Organic Solar Cells

A method of fabricating organic photovoltaic (OPV) tandems that requires no vacuum processing is presented. These devices are comprised of two solution-processed polymeric cells connected in parallel by a transparent carbon nanotubes (CNT) interlayer. This structure includes improvements in fabrication techniques for tandem OPV devices. First the need for ambient-processed cathodes is considered. The CNT anode in the tandem device is tuned via ionic gating to become a common cathode. Ionic gating employs electric double layer charging to lower the work function of the CNT electrode. Secondly, the difficulty of sequentially stacking tandem layers by solution-processing is addressed. The devices are fabricated via solution and dry-lamination in ambient conditions with parallel processing steps. The method of fabricating the individual polymeric cells, the steps needed to laminate them together with a common CNT cathode, and then provide some representative results are described. These results demonstrate ionic gating of the CNT electrode to create a common cathode and addition of current and efficiency as a result of the lamination procedure.

A method of fabricating, in ambient conditions, organic photovoltaic tandem devices in a parallel configuration is presented. These devices feature an air-processed, semi-transparent, carbon nanotube common cathode.

Método ambiente para la producción de un cátodo común iónicamente cerrada nanotubos de carbono en las células solares en tándem Orgánica

A method of fabricating organic photovoltaic (OPV) tandems that requires no vacuum processing is presented. These devices are comprised of two ...

Electron Channeling Contrast Imaging for Rapid III-V Heteroepitaxial Characterization

Misfit dislocations in heteroepitaxial layers of GaP grown on Si(001) substrates are characterized through use of electron channeling contrast imaging (ECCI) in a scanning electron microscope (SEM). ECCI allows for imaging of defects and crystallographic features under specific diffraction conditions, similar to that possible via plan-view transmission electron microscopy (PV-TEM). A particular advantage of the ECCI technique is that it requires little to no sample preparation, and indeed can use large area, as-produced samples, making it a considerably higher throughput characterization method than TEM. Similar to TEM, different diffraction conditions can be obtained with ECCI by tilting and rotating the sample in the SEM. This capability enables the selective imaging of specific defects, such as misfit dislocations at the GaP/Si interface, with high contrast levels, which are determined by the standard invisibility criteria. An example application of this technique is described wherein ECCI imaging is used to determine the critical thickness for dislocation nucleation for GaP-on-Si by imaging a range of samples with various GaP epilayer thicknesses. Examples of ECCI micrographs of additional defect types, including threading dislocations and a stacking fault, are provided as demonstration of its broad, TEM-like applicability. Ultimately, the combination of TEM-like capabilities &#8211; high spatial resolution and richness of microstructural data &#8211; with the convenience and speed of SEM, position ECCI as a powerful tool for the rapid characterization of crystalline materials.

The use of electron channeling contrast imaging in a scanning electron microscope to characterize defects in III-V/Si heteroexpitaxial thin films is described. This method yields similar results to plan-view transmission electron microscopy, but in significantly less time due to lack of required sample preparation.

Electron Canalización de imágenes de contraste para Rapid III-V heteroepitaxial Caracterización

Misfit dislocations in heteroepitaxial layers of GaP grown on Si(001) substrates are characterized through use of electron channeling contrast imaging ...

Experiments on Ultrasonic Lubrication Using a Piezoelectrically-assisted Tribometer and Optical Profilometer

Friction and wear are detrimental to engineered systems. Ultrasonic lubrication is achieved when the interface between two sliding surfaces is vibrated at a frequency above the acoustic range (20 kHz). As a solid-state technology, ultrasonic lubrication can be used where conventional lubricants are unfeasible or undesirable. Further, ultrasonic lubrication allows for electrical modulation of the effective friction coefficient between two sliding surfaces. This property enables adaptive systems that modify their frictional state and associated dynamic response as the operating conditions change. Surface wear can also be reduced through ultrasonic lubrication. We developed a protocol to investigate the dependence of friction force reduction and wear reduction on the linear sliding velocity between ultrasonically lubricated surfaces. A pin-on-disc tribometer was built which differs from commercial units in that a piezoelectric stack is used to vibrate the pin at 22 kHz normal to the rotating disc surface. Friction and wear metrics including effective friction force, volume loss, and surface roughness are measured without and with ultrasonic vibrations at a constant pressure of 1 to 4 MPa and three different sliding velocities: 20.3, 40.6, and 87 mm/sec. An optical profilometer is utilized to characterize the wear surfaces. The effective friction force is reduced by 62% at 20.3 mm/sec. Consistently with existing theories for ultrasonic lubrication, the percent reduction in friction force diminishes with increasing speed, down to 29% friction force reduction at 87 mm/sec. Wear reduction remains essentially constant (49%) at the three speeds considered.

We present a protocol for using a piezoelectrically-assisted tribometer and optical profilometer to investigate the dependence of ultrasonic wear and friction reduction on linear velocity, contact pressure, and surface properties.

Los experimentos en ultrasónico Lubricación El uso de un Tribómetro asistida piezoeléctrico y Perfilómetro óptico

Friction and wear are detrimental to engineered systems. Ultrasonic lubrication is achieved when the interface between two sliding surfaces is vibrated at ...

Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis

Nuclear reaction analysis (NRA) via the resonant 1H(15N,&#945;&#947;)12C reaction is a highly effective method of depth profiling that quantitatively and non-destructively reveals the hydrogen density distribution at surfaces, at interfaces, and in the volume of solid materials with high depth resolution. The technique applies a 15N ion beam of 6.385 MeV provided by an electrostatic accelerator and specifically detects the 1H isotope in depths up to about 2 &#956;m from the target surface. Surface H coverages are measured with a sensitivity in the order of ~1013 cm-2 (~1% of a typical atomic monolayer density) and H volume concentrations with a detection limit of ~1018 cm-3 (~100 at. ppm). The near-surface depth resolution is 2-5 nm for surface-normal 15N ion incidence onto the target and can be enhanced to values below 1 nm for very flat targets by adopting a surface-grazing incidence geometry. The method is versatile and readily applied to any high vacuum compatible homogeneous material with a smooth surface (no pores). Electrically conductive targets usually tolerate the ion beam irradiation with negligible degradation. Hydrogen quantitation and correct depth analysis require knowledge of the elementary composition (besides hydrogen) and mass density of the target material. Especially in combination with ultra-high vacuum methods for in-situ target preparation and characterization, 1H(15N,&#945;&#947;)12C NRA is ideally suited for hydrogen analysis at atomically controlled surfaces and nanostructured interfaces. We exemplarily demonstrate here the application of 15N NRA at the MALT Tandem accelerator facility of the University of Tokyo to (1) quantitatively measure the surface coverage and the bulk concentration of hydrogen in the near-surface region of a H2 exposed Pd(110) single crystal, and (2) to determine the depth location and layer density of hydrogen near the interfaces of thin SiO2 films on Si(100).

We illustrate the application of 1H(15N,&#945;&#947;)12C resonant nuclear reaction analysis (NRA) to quantitatively evaluate the density of hydrogen atoms on the surface, in the volume, and at an interfacial layer of solid materials. The near-surface hydrogen depth profiling of a Pd(110) single crystal and of SiO2/Si(100) stacks is described.

La cuantificación de las concentraciones de hidrógeno en superficies e interfaces de capas y materiales a granel a través de perfiles de profundidad con el análisis de Reacción nuclear

Nuclear reaction analysis (NRA) via the resonant 1H(15N,&#945;&#947;)12C reaction is a highly effective method of depth profiling that quantitatively and ...

Effect of Bending on the Electrical Characteristics of Flexible Organic Single Crystal-based Field-effect Transistors

The charge transport in an organic semiconductor depends highly on the molecular packing in the crystal, which influences the electronic coupling immensely. However, in soft electronics, in which organic semiconductors play a critical role, the devices will be bent or folded repeatedly. The effect of bending on the crystal packing and thus the charge transport is crucial to the performance of the device. In this manuscript, we describe the protocol to bend a single crystal of 5,7,12,16-tetrachloro-6,13-diazapentacene (TCDAP) in the field-effect transistor configuration and to obtain reproducible I-V characteristics upon bending the crystal. The results show that bending a field-effect transistor prepared on a flexible substrate results in nearly reversible yet opposite trends in charge mobility, depending on the bending direction. The mobility increases when the device is bent toward the top gate/dielectric layer (upward, compressive state) and decreases when bent toward the crystal/substrate side (downward, tensile state). The effect of bending curvature was also observed, with greater mobility change resulting from higher bending curvature. It is suggested that the intermolecular &#960;-&#960; distance changes upon bending, thereby influencing the electronic coupling and the subsequent carrier transport ability.

This manuscript describes the bending process of an organic single crystal-based field-effect transistor to maintain a functioning device for electronic property measurement. The results suggest that bending causes changes in the molecular spacing in the crystal and thus in the charge hopping rate, which is important in flexible electronics.

Efecto de doblez en las características eléctricas de los transistores de efecto de campo basados ​​en cristal orgánico único flexible

The charge transport in an organic semiconductor depends highly on the molecular packing in the crystal, which influences the electronic coupling ...

Experimental Implementation of a New Composite Fabrication Method: Exposing Bare Fibers on the Composite Surface by the Soft Layer Method

The bipolar plate is a key component in proton exchange membrane fuel cells (PEMFCs) and vanadium redox flow batteries (VRFBs). It is a multi-functional component that should have high electrical conductivity, high mechanical properties, and high productivity.
In this regard, a carbon fiber/epoxy resin composite can be an ideal material to replace the conventional graphite bipolar plate, which often leads to the catastrophic failure of the entire system because of its inherent brittleness. Though the carbon/epoxy composite has high mechanical properties and is easy to manufacture, the electrical conductivity in the through-thickness direction is poor because of the resin-rich layer that forms on its surface. Therefore, an expanded graphite coating was adopted to solve the electrical conductivity issue. However, the expanded graphite coating not only increases the manufacturing costs but also has poor mechanical properties.
In this study, a method to expose fibers on the composite surface is demonstrated. There are currently many methods that can expose fibers by surface treatment after the fabrication of the composite. This new method, however, does not require surface treatment because the fibers are exposed during the manufacture of the composite. By exposing bare carbon fibers on the surface, the electrical conductivity and mechanical strength of the composite are increased drastically.

A protocol to expose bare fibers on the composite surface by eliminating resin rich area is presented. The fibers are exposed during fabrication of the composites, not by the post surface treatment. The exposed carbon composites exhibit high electrical conductivity in the through-thickness direction and high mechanical property.

Implementación experimental de un nuevo método de fabricación compuesto: exponer desnudas fibras en la superficie del compuesto por el método de capa suave

The bipolar plate is a key component in proton exchange membrane fuel cells (PEMFCs) and vanadium redox flow batteries (VRFBs). It is a multi-functional ...