A paraffin wax and copper foam matrix were used as a thermal energy storage material in the double passes air solar chimney (SC) collector to get ventilation effect through daytime and after sunset. Air SC collector was installed in the south wall of an insulated test room and tested with different working angles (30o, 45o and 60o). Different SC types were used; single pass, double passes flat plate collector and double pass thermal energy storage box collector (TESB). A computational model based on the finite volume method for transient tw dimensional domains was carried out to describe the heat transfer and storage in the thermal energy storage material of collector. Also, equivalent specific heat method was employed to describe the heat storage and release in the mushy zone. Experimental results referred to an increase in thermal conductivity of paraffin wax that supported by copper foam matrix more than ten times. While the ventilation effect was still active for hours after the sun set, depending on the heat storage amount. Maximum ventilation mass flow rate with TESB collector was recorded with value equals to 36.651 kg/hr., when the overall discharge coefficient that was calculated for the system equals to 0.371. Experimental results showed that the best working angle range was 45~60o, and the highest air to the collector approaching temperature appeared to the double passes flat plate collector. Results gave greater heat storage efficiency of (47)% when the maximum solar radiation was 780 W/m2 at 12.00pm, while the energy summation through duration charge time was 18460 kJ. Computational results, depending on the equivalent heat capacity method for heat storage or release from phase change material that supported by copper foam matrix, showed the behavior of paraffin wax melting and solidification situation through periodic for charge and released heat from the solar collector. Also, these results gave agreement approaching the experimental results for the heat storage in the combined heat storage material, with standard error of 16.8%.
Desde la Salamanca de doradas piedras que tantas veces cantara, don Miguel de Unamuno dio a la literatura y al pensamiento españoles unas obras que, a pesar de muchos pesares, perdura viva, como viva fue su agónica existencia.
El bilbaíno Miguel de Unamuno (1864-1936) es autor de al menos, doce obras teatrales. Su costumbre de mezclar géneros literarios, sin distinguir claramente el drama de la novela dialogada, le llevó a preferir el teatro leído. De ahí que sus estrenos fuesen, frecuentemente, muy posteriores a las ediciones impresas.
Abstract:
The Bilbao Miguel de Unamuno (1864-1936) is the author of at least twelve plays. His habit of mixing genres,
... Show Moreالحركات الاسلامية في ظل الوضع الدولي الجديد
العراق في مواجهة متطلبات الانضمام الى منظمة التجارة العالمية
The Research aimed for identification the significant of health problems that occurrences through
misused of computer for those whom attaches with more than two hours daily and to identification the
nature of demographical characteristics variables and that related variables with using computer. Also to
know the level of user’s knowledge for some attaché’s equipment's and finally creating a new suggested
measurement scale for studying health problems that were occurred through misused of computer.
Creating questionnaire includes several domains (Social problems – family environment, Social problems –
external environment, some health problems attaches with related equipment's, psychological problems,
and hea
The development in manufacturing computers from both (Hardware and Software) sides, make complicated robust estimators became computable and gave us new way of dealing with the data, when classical discriminant methods failed in achieving its optimal properties especially when data contains a percentage of outliers. Thus, the inability to have the minimum probability of misclassification. The research aim to compare robust estimators which are resistant to outlier influence like robust H estimator, robust S estimator and robust MCD estimator, also robustify misclassification probability with showing outlier influence on the percentage of misclassification when using classical methods. ,the other
... Show MoreThis study deals with the region of the Babylon governorate in Iraq during the Proto-Literate and Early Dynastic periods. It is the region of the well- known ancient capital Babylon. The earlier period includes Late Uruk, Jamdat nasr, and the first epoch of the Early Dynastic period. The latter includes the second and third epochs of the Early Dynastic period. The both periods had lasted more than one thousand years (3500-2334 BC
The present research deals with the influencing factors which depends on the way perceptual of the graphic designer which enters in the design logos of the loco European health, where the search include four chapters, the researcher reviewed in the chapter 0ne the methodical frame of the research ,as reviewed in the second chapter the theoretical frame, and the previous studies which included three sections, the first section included the perceptual understandable and types of it, and the second section included the influencing factors in the designer perceptual ways and its division . While the third section included the perceptual in graphic designer through the percepted shapes and the relation with ground and colors for express the i
... Show MoreThe Arab woman expressed the life of oppression that she suffers from in her masculine environment, as she expressed her linguistic abilities with eloquence and intelligence, as she did not neglect philosophy, wisdom,
The Arab woman expressed the life of oppression that she suffers from in her masculine environment, as she expressed her linguistic abilities with eloquence and intelligence, as she did not neglect philosophy, wisdom, and exhortation
Resumen:
En este artículo se indaga sobre fenómenos como la metáfora, la metonimia, la polisemia, y la homonimia en las lenguas árabe y española, según la teoría cognitiva, basada en el pensamiento y la práctica lingüística. Esta teoría intenta investigar la relación entre el lenguaje humano, la mente y la experiencia. En realidad, los fenómenos que estudiaremos crean ambigüedad léxica y sintáctica tanto en árabe como en español. Además, dichos conceptos tienen sus propias características, especificaciones y formas en cada lengua.
Abstract:
This article studies phenomena such as metaphor, metonymy, polysemy, homonymy in Arabic and Spanish, according to cognitive theory, based on linguistic thought a
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