<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0035-001X</journal-id>
<journal-title><![CDATA[Revista mexicana de física]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. mex. fis.]]></abbrev-journal-title>
<issn>0035-001X</issn>
<publisher>
<publisher-name><![CDATA[Sociedad Mexicana de Física]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0035-001X2002000600013</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Ciclo de Curzon y Ahlborn para un gas de van der Waals]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Ladino-Luna]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Instituto Politécnico Nacional Escuela Superior de Ingeniería Mecánica y Eléctrica Departamento de Ingeniería en Comunicaciones y Electrónica]]></institution>
<addr-line><![CDATA[México Distrito Federal]]></addr-line>
<country>México</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>00</month>
<year>2002</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>00</month>
<year>2002</year>
</pub-date>
<volume>48</volume>
<numero>6</numero>
<fpage>575</fpage>
<lpage>578</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0035-001X2002000600013&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0035-001X2002000600013&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0035-001X2002000600013&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Se muestra que para una máquina térmica tipo Kurzon y Ahlborn con un gas de van der Waals, como substancia de trabajo, utilizando maximización de potencia y maximización de función ecológica, se obtienen las mismas expresiones que para la eficiencia en el caso de un gas ideal como substancia de trabajo, salvo la substitución de los volúmenes máximo y mínimo, subtendidos por la máquina, en la forma Vmax &#8594; Vmax - b y Vmin &#8594; Vmin - b, en donde sea necesario. Las ramas adiabáticas del ciclo se consideran no instantáneas.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[For a Curzon and Ahlborn type heat engine with a van der Waals gas like a working substance, using maximization of power and maximization of ecological function, it is shown that the same expression of the efficiency for the ideal gas case as working substance, with the substitution of maximum volume and minimum volume spanned by the engine, Vmax &#8594; Vmax - b and Vmin &#8594; Vmin - b, are obtained. The adiabatic branches in the cycle are consider non instantaneous.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Termodinámica de tiempos finitos]]></kwd>
<kwd lng="es"><![CDATA[gas de van der Waals]]></kwd>
<kwd lng="en"><![CDATA[Finite time thermodynamics]]></kwd>
<kwd lng="en"><![CDATA[van der Waals gas]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[  	    <p align="justify"><font face="verdana" size="4">Ense&ntilde;anza</font></p>  	    <p>&nbsp;</p>  	    <p align="center"><font face="verdana" size="4"><b>Ciclo de Curzon y Ahlborn para un gas de van der Waals</b></font></p>  	    <p>&nbsp;</p>  	    <p align="center"><font face="verdana" size="2"><b>D. Ladino&#45;Luna<a href="#nota">*</a></b></font></p>  	    <p>&nbsp;</p>  	    <p align="justify"><font face="verdana" size="2"><i>Dpto. de ICE, ESIME&#45;IPN, Edif. 4, U. P. Zacatenco Av. I.P.N. s/n Col. San Pedro Zacatenco, 07738, D.F., M&eacute;xico</i>.</font></p>  	    <p>&nbsp;</p>  	    <p align="justify"><font face="verdana" size="2">Recibido el 25 de febrero de 2002.    ]]></body>
<body><![CDATA[<br> 	Aceptado el 17 de junio de 2002.</font></p>  	    <p>&nbsp;</p>  	    <p align="justify"><font face="verdana" size="2"><b>Resumen</b></font></p>  	    <p align="justify"><font face="verdana" size="2">Se muestra que para una m&aacute;quina t&eacute;rmica tipo Kurzon y Ahlborn con un gas de van der Waals, como substancia de trabajo, utilizando maximizaci&oacute;n de potencia y maximizaci&oacute;n de funci&oacute;n ecol&oacute;gica, se obtienen las mismas expresiones que para la eficiencia en el caso de un gas ideal como substancia de trabajo, salvo la substituci&oacute;n de los vol&uacute;menes m&aacute;ximo y m&iacute;nimo, subtendidos por la m&aacute;quina, en la forma <i>V<sub>max</sub></i> &rarr; <i>V<sub>max</sub> &#151; b</i> y <i>V<sub>min</sub></i> &rarr; <i>V<sub>min</sub> &#151; b,</i> en donde sea necesario. Las ramas adiab&aacute;ticas del ciclo se consideran no instant&aacute;neas.</font></p>  	    <p align="justify"><font face="verdana" size="2"><b>Descriptores:</b> Termodin&aacute;mica de tiempos finitos; gas de van der Waals.</font></p>  	    <p>&nbsp;</p>  	    <p align="justify"><font face="verdana" size="2"><b>Abstract</b></font></p>  	    <p align="justify"><font face="verdana" size="2">For a Curzon and Ahlborn type heat engine with a van der Waals gas like a working substance, using maximization of power and maximization of ecological function, it is shown that the same expression of the efficiency for the ideal gas case as working substance, with the substitution of maximum volume and minimum volume spanned by the engine, <i>V<sub>max</sub></i> &rarr; <i>V<sub>max</sub> &#151; b</i> and <i>V<sub>min</sub></i> &rarr; <i>V<sub>min</sub> &#151; b,</i> are obtained. The adiabatic branches in the cycle are consider non instantaneous.</font></p>  	    <p align="justify"><font face="verdana" size="2"><b>Keywords:</b> Finite time thermodynamics; van der Waals gas.</font></p>  	    <p>&nbsp;</p>  	    ]]></body>
<body><![CDATA[<p align="justify"><font face="verdana" size="2">PACS: 44.6+k; 44.90+c</font></p>  	    <p>&nbsp;</p>  	    <p align="justify"><font face="verdana" size="2"><a href="/pdf/rmf/v48n6/v48n6a13.pdf" target="_blank">DESCARGAR ART&Iacute;CULO EN FORMATO PDF</a></font></p>  	    <p>&nbsp;</p>     <p align="justify"><font face="verdana" size="2"><b>Referencias</b></font></p>  	    <!-- ref --><p align="justify"><font face="verdana" size="2">1. A. De Vos, <i>Endoreversible Thermodynamics of Solar Energy Conversion</i> (Oxford University Press, Oxford, 1992).    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8290921&pid=S0035-001X200200060001300001&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>  	    <!-- ref --><p align="justify"><font face="verdana" size="2">2. H. B. Callen, <i>Thermodynamics and an Introduction to Thermostatistics</i> (Wiley, New York, 1985).    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8290923&pid=S0035-001X200200060001300002&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>  	    <!-- ref --><p align="justify"><font face="verdana" size="2">3. F. L. Curzon and B. Ahlborn, <i>Am. J. Phys.</i> <b>43</b> (1975) 22.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8290925&pid=S0035-001X200200060001300003&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>  	    <!-- ref --><p align="justify"><font face="verdana" size="2">4. F. Angulo&#45;Brown, <i>J. Appl. Phys.</i> <b>69</b> (1991) 7465.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8290927&pid=S0035-001X200200060001300004&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>  	    <!-- ref --><p align="justify"><font face="verdana" size="2">5. D. Gutkowics&#45;Krusin, I. Procaccia and J. Ross, <i>J. Chem. Phys.</i> <b>69</b> (1978) 3898.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8290929&pid=S0035-001X200200060001300005&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>  	    <!-- ref --><p align="justify"><font face="verdana" size="2">6. D. Ladino&#45;Luna and S.M.T. de la Selva, <i>Rev. Mex. F&iacute;s.</i> <b>46</b> (2000) 52.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8290931&pid=S0035-001X200200060001300006&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>      <!-- ref --><p align="justify"><font face="verdana" size="2">7. E. Fermi, <i>Thermodynamics</i> (Columbia University Press, N. Y., 1936).    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8290933&pid=S0035-001X200200060001300007&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>  	    <!-- ref --><p align="justify"><font face="verdana" size="2">8. E. Pifea, <i>Termodin&aacute;mica,</i> (Limusa, M&eacute;xico, 1978).    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=8290935&pid=S0035-001X200200060001300008&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></font></p>  	    <p>&nbsp;</p>  	    <p align="justify"><font face="verdana" size="2"><a name="nota"></a><b>Nota</b></font></p>  	    <p align="justify"><font face="verdana" size="2">* Tambi&eacute;n UAM&#45;AZC.</font></p>      ]]></body><back>
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</article>
