Improvement the thermal performance of Myristic acid

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.This study mainly focus on two aspects; the first one is to increase the thermal conductivity of Myristic acid with graphene additives and the second one is to determine the influence of this increment on the melting duration of a particular encapsulated thermal energy storage system with PCM. As a result, thermal conductivity of composite myristic acid increased by 8%, 18% and 38% after graphene loadings of 0.5%, 1% and 2% into the pure MA, respectively. Besides, one-dimensional spherical computational domain has been considered, and the conduction dominated phase change process simulated with implementing temperature transformation method. Validity of the current code has been revealed by reproducing a numerical work in literature. For this particular case, it is found that the increments of 8%, 18% and 38% in thermal conductivity tend to reduce the total time of melting by 5.6%, 15% and 26%.dc201

Okullarda sportif aktivitelerde ortaya çıkan ani ölümler

This is the first study which aims to investigate to sudden deaths in sportive activities at schools in Turkey retrospectively. The aim here is to dedicate the sudden deaths according to age, sex, branch, time and cause and take caution for these. Fifteen sudden deaths cases between 1991-2005 are examined with this target. These cases are 10 % (% 66.7) primary school students, 5 % (% 32.3) high school students. Moreover 13 boys and 2 girls. The rate of the boys to the girls are 1/7.5 and age rate of sudden deaths are 15.0. The sudden deaths in schools took place 6 % in Physical Educations, 4 % at the break while they were playing with ball, 2 % in the exercises out of lessons, % 1 in competitions between schools or classes and 1 % in the rehearsals in 19 th May exercises. 9 of the cases happened while they were playing football, 4 while playing basketball, 1 in a competition of folklore, and 1 in the rehearsal of exercises. It's declared that sudden deaths in sportive activities increased in 2004 and 2005. The cause in 12 case (80 %) is cardiovascular, 3 (20 %) is traumatic. Autopsy is hold in 33.3 % of the cases and autopsy is not hold in 66.7 % of the deaths. The causes in 80 % hearth attack, 13.3 % brain blood and 6.7 % inefficiency of heart. In order to prevent sudden deaths in sportive activities, students' heart should be examined and information about diagnosis, sport emergency and first aid autopsy should be given to the students

Sudden Deaths that Occures During the Sportive Acrivities at Schools

Bu çalışma; Türkiye’de okullarda sportif aktivitelerde ortaya çıkan ani ölümlerin retrospektif olarak incelenmesini amaçlayan ilk çalışmadır. Bu çalışma ile öğrencilerde sportif aktivitelerde ortaya çıkan ani ölümlerin yaşa, cinsiyete, branşa, zamana ve ölüm nedenine göre belirlenmesi ile bu tür ölümlerin önlenmesine ilişkin tedbirlerin tartışılması amaçlandı. Bu amaçla 1991-2005 yılları arasında ortaya çıkan 15 ani ölüm vakası tespit edildi. Bu vakalardan 10’u (% 66.7) ilköğretim, 5’i (% 33.3) ise lise öğrencisi olup 13’ü erkek 2’si kız öğrencidir. Erkeklerin kızlara oranı 1/7.5, ani ölen öğrencilerin yaş ortalaması 15.0’dır. Okullarda sportif aktivitelerde ortaya çıkan ani ölümlerin 6’sı beden eğitimi dersinde, 4’ü teneffüste top oynarken, 2’si Ders dışı eğitim faaliyetinde (egzersizde), 1’i Okullar ve sınışar arası yarışmada, 1’i ise 19 Mayıs provalarında ortaya çıktığı bulundu. Bu vakalardan 9’u futbol oynarken, 4’ü basketbol oynarken, 1’i halkoyunları yarışmasında ve 1’i de bayram provalarında ortaya çıkmı ştır. Okullarda sportif aktivitelerde ortaya çıkan ani ölümlerin 2004 ve 2005 yıllarında artış gösterdiği belirlendi. Gerçekleşen ani ölümlerin 12’si (% 80) kardiyovasküler 3’ü (% 20) ise travmatik nedenlidir. Ani ölümlerin % 33.3 otopsi yapılırken % 66.7’sine otopsi yapılmamıştır. Öğrencilerdeki ani ölümlerin nedenlerini; % 80‘i Kalp Krizi, % 13.3‘ü Beyin Kanaması ve % 6.7‘si Kalp Yetmezliğ i oluşturmaktadır. Okullarda sportif aktivitelerde ortaya çıkan ani ölümlerin önlenmesinde öğrenci sağlık muayenelerinin yapılması, spor sakatlıkları ve ilk yardım konusunda uygulamalı eğitim verilmesi ve otopsi yapılması oldukça önemlidir.This is the first study which aims to investigate to sudden deaths in sportive activities at schools in Turkey retrospectively. The aim here is to dedicate the sudden deaths according to age, sex, branch, time and cause and take caution for these. Fifteen sudden deaths cases between 1991-2005 are examined with this target. These cases are 10 % (% 66.7) primary school students, 5 % (% 32.3) high school students. Moreover 13 boys and 2 girls. The rate of the boys to the girls are 1/7.5 and age rate of sudden deaths are 15.0. The sudden deaths in schools took place 6 % in Physical Educations, 4 % at the break while they were playing with ball, 2 % in the exercises out of lessons, % 1 in competitions between schools or classes and 1 % in the rehearsals in 19 th May exercises. 9 of the cases happened while they were playing football, 4 while playing basketball, 1 in a competition of folklore, and 1 in the rehearsal of exercises. It’s declared that sudden deaths in sportive activities increased in 2004 and 2005. The cause in 12 case (80 %) is cardiovascular, 3 (20 %) is traumatic. Autopsy is hold in 33.3 % of the cases and autopsy is not hold in 66.7 % of the deaths. The causes in 80 % hearth attack, 13.3 % brain blood and 6.7 % inefficiency of heart. In order to prevent sudden deaths in sportive activities, students’ heart should be examined and information about diagnosis, sport emergency and first aid autopsy should be given to the students

DETERMINATION OF FACTORS AFFECTING SPORTS PARTICIPATION MOTIVATION OF HIGH SCHOOL STUDENTS WHO MAKE SPORTS

Bu araştırma; liselerde eğitim gören ve spor yapan öğrencilerin spora katılım motivasyonlarını belirlemek; cinsiyet, yaş, yaptıkları spor branşları ve spora başlama sürelerine göre spora katılım güdülerinin farklılaşıp farklılaşmadığını incelemek amacıyla yapılmıştır. Araştırmanın evrenini, 2006–2007 eğitim-öğretim yılında, Osmaniye ilinde ders dışı okullar arası spor faaliyetlerine katılan 1156 kız ve erkek sporcu öğrenci oluşturmuştur. Araştırmanın örneklemi ise farklı branşlarda okullarını temsil eden ve müsabakalara katılmış 270 sporcu öğrenciden oluşmuştur. Araştırmada veri toplama aracı olarak, araştırmacı tarafından geliştirilen kişisel bilgi formu ve Gill, ve ark. (1983)’ un geliştirdiği ve Oyar ve ark. (2001) tarafından Türk popülasyonuna uyarlaması yapılan Spora Katılım Güdüsü ölçeği (Participation Motivation Questionnaire) (PMQ) kullanılmıştır. Verilerin analizinde, t testi ve Tek Yönlü Varyans Analizi (Anova) kullanılmış, anlamlılık düzeyi 0.05 olarak alınmıştır. Araştırma sonucunda spor yapan lise öğrencilerinin spora katılım motivasyonları dışsal güdülerden çok “takım üyeliği/ruhu”, “beceri gelişimi” ve “hareket/aktif olma” olarak bulunmuştur. Spora katılım nedenlerinde cinsiyet farklılığında kız ve erkek sporcular arasında “eğlence” ve “hareket/aktif olma” alt boyutlarında kız sporcuların lehine bir fark olduğu belirlenmiştir. Spora katılım nedenlerinde yaş farklılığında “takım üyeliği/ruhu” “eğlence”, “başarı/statü” ve “hareket/aktif olma” alt boyutlarında anlamlı düzeyde farklılaşma bulunmuştur. Voleybol, futbol, basketbol ve diğer branşlarla ilgilenen sporcuların spora katılım motivasyonları “yarışma” ve “arkadaş” alt boyutları düzeyinde farklılaştığı tespit edilmiştir. Spora başlama süresine göre sporcuların spora katılım motivasyonları “takım üyeliği/ruhu” ve “arkadaş” alt boyutlarında farklılaştığı bulunmuştur. Anahtar Kelimeler: Spora Katılım motivasyonu, Lise Öğrencileri, Spor, cinsiyet, yaşThis study was carried on in order to determine the sports participation motivation of high school students who make sports and to observe the difference in their sports participation motivation according to gender, age, sports branch and beginning to sports time. The universe of the study was constituted of 1156 boys and girls in Osmaniye who participated to sports activities in 2006-2007 educational years. The sample of this study is 270 students who were the representatives of their schools in sports activities. The data collecting instruments are personal information form which was developed by the researcher and Participation Motivation Questionnaire (PMQ) which was developed by Gill et al. (1983) and which was adapted to Turkey by Oyar et al (2001). t test and ANOVA were used in analyzing the data and the significance level was taken as 0.05. Sports participation motivation of students was found as “team membership/spirit”, “skill development” and “movement/being active” rather than exterior motives. There is a significant difference in “fun” and “movement/being active” sub dimensions between boys and girls in the favour of girls. There is significant difference in “team membership/spirit”, “fun”, “success/status” and “movement/being active” sub dimensions in the reasons of sports participation. The motivations of the athletes who are interested in volleyball, football, basketball and other branches differentiated in the “competition” and “friend” sub dimensions. The sport participation motivation of athletes differentiated in “team membership/spirit” and “friend” sub dimensions according to beginning of sports time.

Development and evaluation of graphite nanoplate (GNP)-based phase change material for energy storage applications

© 2015 John Wiley & Sons, Ltd.In this study, arachidic acid (AA)/graphite nanoplate (GNP) composite material is proposed as a novel phase change material (PCM). In order to examine the influence of GNP loading into the base material (AA), composite PCMs were prepared with three different fractions (0.5, 1.0 and 2.0 in wt%). The thermal, chemical and morphological characteristics of the samples were introduced in terms of differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared, and X-ray diffraction analyses. Moreover, the thermal conductivity values of samples in the liquid state were measured by means of 3ω method. It was found that, for GNP fractions of 0.5, 1, and 2 wt. %, the thermal conductivity of composite PCMs have been increased by 15, 30 and 43% in comparison to the pure AA. Results also revealed that the GNP loading into the pure AA led to a reduction in the degree of subcooling and a small diminution in the latent heat values. Considering the thermal cycling tests, it was also obtained that the proposed composite PCMs remained stable even at the highest GNP loading. Conduction-dominated inward solidification process was simulated for one-dimensional spherical computational domain. For this particular case, it was found that the increments of 15, 30 and 45% in thermal conductivity tend to increase the effectiveness by 3.5, 6.4 and 8.7%, respectively

Thermal properties of myristic acid/graphite nanoplates composite phase change materials

Myristic acid-graphite nanoplates (MA/Gr) composite phase change materials were prepared and thermal properties at various Gr loadings, 0.5%, 1% and 2%, were investigated. Melting and freezing temperatures, latent heats of melting and freezing, the extent of supercooling and the crystallization fraction were obtained with respect to the Gr loadings. It is observed that the Gr loading does not affect the crystallization fraction, but decreases the extent of supercooling. The effect of Gr loading on thermal stability and functional groups of myristic acid was determined by thermogravimetric and Fourier transform infrared analyses, respectively. Thermal conductivity of Myristic acid increased by 8%, 18% and 38% after Gr loadings of 0.5%, 1% and 2% into MA, respectively. Thermal cycling test was also conducted at various thermal cycles (1, 10, 40, 70 and 100 cycles). Repeated melting/freezing cycles have no significant effect on the thermal properties and chemical stability of MA/Gr composites. (C) 2014 Elsevier Ltd. All rights reserved

Graphite nanoplates loading into eutectic mixture of Adipic acid and Sebacic acid as phase change material

In this study, a series of binary mixtures of Adipic acid (AA) and Sebacic acid (SA) at various mass fractions were prepared. A binary mixture of AA and SA in the ratio of 48.0:52.0 wt% was shown to be an eutectic mixture with melting temperature of 116 degrees C, melting latent heat of 206.0 J g(-1). In order to improve thermal properties of AA-SA eutectic mixture, multilayer graphite nanoplates (GNP) at different mass fractions (0.1, 0.3, and 0.5 wt%) was loaded into AA-SA mixture. The loading of 0.5 wt% GNP decreased the extent of supercooling from 17.7 to 3.6 degrees C. GNP loading did not change the thermal stability, functional groups and crystallographic properties of AA-SA eutectic mixture. Thermal conductivity of AA-SA was improved by GNP loading. Besides, morphological properties of GNP loaded AA-SA were examined by scanning electron microscopy observations. Thermal reliability of the AA-SA eutectic mixtures was investigated at different thermal cycles. Eutectic mixture of AA-SA containing GNP of 0.1 and 0.5 wt% showed relatively smaller variations in melting temperature and freezing temperatures. (C) 2015 Elsevier B.V. All rights reserved