<?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>1870-3542</journal-id>
<journal-title><![CDATA[Revista mexicana de física E]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. mex. fís. E]]></abbrev-journal-title>
<issn>1870-3542</issn>
<publisher>
<publisher-name><![CDATA[Sociedad Mexicana de Física]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S1870-35422016000100001</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[On thermal waves&#8217; velocity: some open questions in thermal waves&#8217; physics]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Marín]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Vaca-Oyola]]></surname>
<given-names><![CDATA[L.S.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Delgado-Vasallo]]></surname>
<given-names><![CDATA[O.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Instituto Politécnico Nacional Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada ]]></institution>
<addr-line><![CDATA[Mexico ]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Universidad Politécnica Metropolitana de Hidalgo  ]]></institution>
<addr-line><![CDATA[Tolcayuca Hidalgo]]></addr-line>
<country>Mexico</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>06</month>
<year>2016</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>06</month>
<year>2016</year>
</pub-date>
<volume>62</volume>
<numero>1</numero>
<fpage>1</fpage>
<lpage>4</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S1870-35422016000100001&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S1870-35422016000100001&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S1870-35422016000100001&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[This paper presents some considerations about the truly character of thermal waves. Starting from the comparison of typical characteristic velocities, it is shown why a limiting frequency must exists, above which the parabolic treatment of the heat transfer in presence of time varying periodical heat sources is no longer valid due to the constancy of the speed of light in vacuum. Although it is demonstrated that this frequency is much smaller than that at which the thermal wave velocity can become the speed of light, many questions remain open, such as the behavior of thermal waves at intermediary frequencies. The discussion presented here can be useful to stimulate further discussion on this theme among students, teachers and scientists dealing with heat transport under non-stationary conditions.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Heat transfer]]></kwd>
<kwd lng="en"><![CDATA[thermal waves]]></kwd>
<kwd lng="en"><![CDATA[second sound]]></kwd>
</kwd-group>
</article-meta>
</front><back>
<ref-list>
<ref id="B1">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Almond]]></surname>
<given-names><![CDATA[D.P.]]></given-names>
</name>
<name>
<surname><![CDATA[Patel]]></surname>
<given-names><![CDATA[P.M.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Photothermal Science and Techniques]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[Dobbsand]]></surname>
<given-names><![CDATA[E.R.]]></given-names>
</name>
<name>
<surname><![CDATA[Palmer]]></surname>
<given-names><![CDATA[S.B.]]></given-names>
</name>
</person-group>
<source><![CDATA[Physics and its Applications]]></source>
<year>1996</year>
<publisher-loc><![CDATA[London ]]></publisher-loc>
<publisher-name><![CDATA[Chapman and Hall]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B2">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Marin]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<source><![CDATA[Eur. J. Phys]]></source>
<year>2007</year>
<volume>28</volume>
<page-range>429</page-range></nlm-citation>
</ref>
<ref id="B3">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Ordonez-Miranda]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Alvarado-Gil]]></surname>
<given-names><![CDATA[J.J.]]></given-names>
</name>
</person-group>
<source><![CDATA[Int. J. Therm. Sc.]]></source>
<year>2009</year>
<volume>48</volume>
<page-range>2053</page-range></nlm-citation>
</ref>
<ref id="B4">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Marin]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Marin]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Diaz]]></surname>
<given-names><![CDATA[P.]]></given-names>
</name>
</person-group>
<source><![CDATA[Eur, J. Phys.]]></source>
<year>2002</year>
<volume>23</volume>
<page-range>523</page-range></nlm-citation>
</ref>
<ref id="B5">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Salazar]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Eur. J. Phys]]></source>
<year>2006</year>
<volume>27</volume>
<page-range>1349</page-range></nlm-citation>
</ref>
<ref id="B6">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Marin]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<source><![CDATA[Eur. J. Phys]]></source>
<year>2013</year>
<volume>34</volume>
<page-range>L83</page-range></nlm-citation>
</ref>
<ref id="B7">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Joseph]]></surname>
<given-names><![CDATA[D. D.]]></given-names>
</name>
<name>
<surname><![CDATA[Preziosi]]></surname>
<given-names><![CDATA[L.]]></given-names>
</name>
</person-group>
<source><![CDATA[Rev. Mod. Phys.]]></source>
<year>1989</year>
<volume>61</volume>
<page-range>41</page-range></nlm-citation>
</ref>
<ref id="B8">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Soskic]]></surname>
<given-names><![CDATA[Z.]]></given-names>
</name>
<name>
<surname><![CDATA[Popovic]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Cevizovic]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
<name>
<surname><![CDATA[Stojanovic]]></surname>
<given-names><![CDATA[Z.]]></given-names>
</name>
</person-group>
<source><![CDATA[J. Appl. Phys.]]></source>
<year>2014</year>
<volume>116</volume>
</nlm-citation>
</ref>
<ref id="B9">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Vedavarz]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Kumar]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
<name>
<surname><![CDATA[Moallemi]]></surname>
<given-names><![CDATA[M.K.]]></given-names>
</name>
</person-group>
<source><![CDATA[J. Heat Transfer]]></source>
<year>1994</year>
<volume>116</volume>
<page-range>221</page-range></nlm-citation>
</ref>
<ref id="B10">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Gra&#946;Jmann]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Peters]]></surname>
<given-names><![CDATA[F.]]></given-names>
</name>
</person-group>
<source><![CDATA[Heat and Mass Transfer]]></source>
<year>1999</year>
<volume>35</volume>
<page-range>289</page-range></nlm-citation>
</ref>
<ref id="B11">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Roetzel]]></surname>
<given-names><![CDATA[W.]]></given-names>
</name>
<name>
<surname><![CDATA[Putra]]></surname>
<given-names><![CDATA[N.]]></given-names>
</name>
<name>
<surname><![CDATA[Das]]></surname>
<given-names><![CDATA[S. K.]]></given-names>
</name>
</person-group>
<source><![CDATA[Int. J. Heat Mas Transf.]]></source>
<year>2003</year>
<volume>42</volume>
<page-range>541</page-range></nlm-citation>
</ref>
<ref id="B12">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Ordonez-Miranda]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Alvarado-Gil]]></surname>
<given-names><![CDATA[J.J.]]></given-names>
</name>
</person-group>
<source><![CDATA[Int. J. Therm. Sc.]]></source>
<year>2010</year>
<volume>49</volume>
<page-range>209</page-range></nlm-citation>
</ref>
<ref id="B13">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Galovic]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
<name>
<surname><![CDATA[Kostoski]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
</person-group>
<source><![CDATA[J. Appl. Phys.]]></source>
<year>2003</year>
<volume>93</volume>
<page-range>3063</page-range></nlm-citation>
</ref>
<ref id="B14">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Falcon]]></surname>
<given-names><![CDATA[N.]]></given-names>
</name>
<name>
<surname><![CDATA[Labrador]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<source><![CDATA[OdessaAstron. Publ.]]></source>
<year>2001</year>
<volume>14</volume>
<page-range>141</page-range></nlm-citation>
</ref>
<ref id="B15">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Chen]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<source><![CDATA[Int. J. Heat Mas Transf.]]></source>
<year>2006</year>
<volume>49</volume>
<page-range>307</page-range></nlm-citation>
</ref>
<ref id="B16">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Khayat]]></surname>
<given-names><![CDATA[R.E.]]></given-names>
</name>
</person-group>
<source><![CDATA[Int. J. Therm. Sc.]]></source>
<year>2015</year>
<volume>97</volume>
<page-range>163</page-range></nlm-citation>
</ref>
<ref id="B17">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Marin]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<source><![CDATA[Lat. Am. J. Phys. Educ.]]></source>
<year>2010</year>
<volume>4</volume>
<page-range>56</page-range></nlm-citation>
</ref>
</ref-list>
</back>
</article>
