1,4-Di-9-anthrylbutane

In the title compound, C32H26, the molecule has an inversion centre at the mid-point of the central C—C bond. Weak intermolecular C—H...π interactions help to stabilize the crystal structure

1,3-Bi-9-anthrylpropane

The title compound, C31H24, with three molecules in the asymmetric unit. The crystal packing is mainly stabilized by weak C—H⋯π inter­actions in addition to van der Waals forces

Performance Assessment of Flat Plate Solar Collector Using Different Nanofluids

In this work, a numerical study has been performed to investigate the performance of a Flat plate solar collector FPSC using five different nanofluids including Al2 O3 , CeO2 , Cu, SiO2 , and TiO2 as the working fluid with a volume fraction VF range of 0-2% and mass flow rate of 0.02kg/s. A computer program written in MATLAB is developed and the equations are solved in an iterative approach to obtain the output temperature. The model is validated through a comparison with an experimental data that is taken from the literature and a good agreement is obtained. A parametric study is done to investigate the effects of VF’s on the performance of the collector. The analyses have been conducted for the city of Aydın in Turkey. The results show that for VF of 2%, the maximum efficiency augmentation is observed in SiO2 nanofluid by 10%

Sternal abscess overlying giant aortic pseudoaneurysm developed after Bentall procedure Bentall prosedürü sonrası gelişmiş dev aortik pseudoanevrizma üzerine oturmuş sternal apse Olgu Sunumu

Abstract Aortic pseudoaneurysms are one of the most important complications to be encountered in cardiac surgery. Recently, the aortic pseudoaneurysms have been diagnosed by contrast enhanced computerized tomography. It has high specificity and sensitivity rates. Late postoperative sternal abscesses are rarely seen after open heart surgery. Thorax computerized tomography scan revealed abscess extending from subcutaneous tissue to the medullar component of sternum, overlying retrosternal giant aortic pseudoaneurysms. This article presents the case of a patient, who had undergone Bentall procedure three years ago due to type I aortic dissection and later presented in our cardiovascular surgery department with a sternal mass. Pam Med J 2013;6(1):33-36 Key words: Abscess; sternal wound infection; aortic pseudoaneurysm Özet Aortic pseudoanevrizmalar kalp cerrahisinde karşılaşılabilecek en önemli komplikasyonlardan biridir. Son zamanlarda aortic pseudoanevrizmalara kontrastlı bilgisayarlı tomografi ile tanı konmaktadır. Bu test oldukça yüksek özgüllük ve hassasiyet değerlerine sahiptir. Geç dönem sternal apseler açık kalp cerrahisinden sonra nadiren gözlenmektedirler. Bilgisayarlı toraks tomografisinde subkutanöz dokudan başlayıp sternum medullasına kadar uzanan absenin aortik retrosternal dev bir pseudoanevrizma üzerine oturduğu saptandı. Bu makalede; üç yıl önce tip I aortic diseksiyon nedeni ile Bentall ameliyatı olan ve daha sonra sternal kitle yakınmasıyla kalp damar cerrahisi kliniğimize müracaat eden hasta sunulmaktadır. Tıp Derg 2013;6(1):33-36 Pa

مشاكل معاصرة لتمويل تعليم طالب الدراسات العليا وأوجه الاستفادة من صيغ التمويل المستمدة من الاقتصاد الإسلامي دراسة كيفية وصفية بالمصارف الإسلامية بمدينة مالانق

مستخلص البحث الكشف عن حاجة طالب الدراسات العليا في الحصول على تمويل مالي من المصارف الاسلامية لسداد الرسوم الجامعية .ثم التعرف على أدوات وصيغ التمويل الاسلامي المقترحة لتمويل تعليم الطلبة واستعراض مشاكل التمويل التي تواجه المصارف الإسلامية , وأخيرا تحديد أوجه الاستفادة من الصيغ الاسلامية بالمصارف المحلية والخارجية لتمويل رسوم طالب الدراسات العليا . منهج الدراسة : لتحقيق أهداف الدراسة قام الباحث باستخدام المنهج الكيفي والوصفي التحليلي واستخدم الباحث الاستبيان والمقابلة كأدوات رئيسية في جمع البيانات , وقام الباحث باستخدام العديد من الأساليب الإحصائية مثل مقياس ليكارت الخماسي والوزن النسبي والتكرارات . وخلصت الدراسة الي نتائج أهمها : 1.يحتاج 88 % تقريباً من طلبة الدراسات العليا في الحصول على تمويل إسلامي لسداد الرسوم الجامعية . 2.أدوات وصيغ التمويل الاسلامي المقترحة لتمويل تعليم الطلبة ببنك معاملات ومنديري الاسلامي هي: صيغة الإجارة كما يمكن استخدام صيغة الإجارة الموصوفة بالذمة. 3.المشاكل التي تواجه المصارف الإسلامية هي : عدم تفعيل بعض الفتاوى ومختنقات مع المصرف المركزي و صعوبات قانونية وإدارية , والمماطلة في السداد . 4.يمكن الاستفادة من الصيغ الاسلامية بالمصارف المحلية والخارجية وذلك بطرح منتج تمويل تعليم طلبة الدراسات العليا بصيغة الإجارة والإجارة الموصوفة بالذمة والمرابحة . ABSTRAK Tujuan penelitian ini adalah untuk mengungkap tingkat kebutuhan mahasiswa Pascasarjana dalam memperoleh pendanaan biaya kuliah dari Bank Islam, mengetahui perangkat dan bentuk-bentuk pembiayaan islam (Islamic Finance) yang diajukan untuk pembiayaan bagi mahasiswa pascasarjana dan menjelaskan masalah pembiayaan yang dihadapi beberapa bank Islam, dan untuk menentukan sisi pemanfaatan dari berbagai bentuk pembiayaan secara islami pada bank-bank lokal dan internasional dalam hal pendanaan biaya kuliah mahasiswa pascasarjana. Peneliti menggunakan metode angket/sampling dan wawancara guna merealisasikan tujuan di atas sebagai inti instrumen penelitian dalam pengumpulan data. Selain itu, peneliti menggunakan metode penelitian kualitatif dan metode deskriptif analisis, serta menggunakan model-model statistik seperti skala likert (fifth likert scale) dan linear weighted moving average. Hasil penelitian menunjukkan bahwa (1) 88% dari mahasiswa pascasarjana membutuhkan dana biaya perkuliahan secara islami. (2) Instrumen dan bentuk-bentuk pendanaan yang disediakan untuk mendanai biaya kuliah bagi mahasiswa di Bank Mandiri dan Bank Muamalat adalah bentuk ijarah, seperti bentuk ijarah dengan jaminan. (3) Masalah-masalah yang dihadapi oleh beberapa bank Islam adalah tidak menjalankan beberapa kebijakan, tidak sepaham dengan bank pusat, kesulitan aturan dan administrasi, serta lamban dalam proses pembiayaan. (4) Memanfaatkan bentuk-bentuk pendanaan secara islami dari bank-bank lokal dan internasional dengan cara mengajukan produk pendanaan biaya kuliah mahasiswa pascasarjana dalam bentuk ijarah dengan jaminan dan bagi hasil (murabahah)

Parametric study of phase change material heat exchanger

WOS: 000384552000008In this work a phase change material unit which consist of shell and tube heat exchanger in which tubes are vertical and filled with a phase change material that melts at 23 degrees C is used. First a numerical method for the design of phase change material cooler is presented then a numerical solution is obtained and compared with results of published analytical solution. The volume of phase change material heat exchanger is taken constant and a parametric study such as tube pitch, fans speed and phase change material is made. For all four cases of tube arrangement, it is found that as the tube pitch doubled in the direction of the flow, the total melting time decreased about 38%

Faz değişim malzemeli ısı değiştirici üzerine parametrik bir çalışma

In this work a phase change material unit which consist of shell and tube heat exchanger in which tubes are vertical and filled with a phase change material that melts at 23;deg;C is used. First a numerical method for the design of phase change material cooler is presented then a numerical solution is obtained and compared with results of published analytical solution. The volume of phase change material heat exchanger is taken constant and a parametric study such as tube pitch, fans speed and phase change material is made. For all four cases of tube arrangement, it is found that as the tube pitch doubled in the direction of the flow, the total melting time decreased about 38%Bu çalışmada, boruları düşey konumda olan gövde boru tipi bir ısı değiştiricide, borular içinde 23°C sıcaklıkta ergiyebilen faz değişim malzemesi bulunan bir sistem ele alınmıştır. Isı transfer akışkanı olan hava sisteme fan aracılığıyla sağlanmıştır. Bu çalışmada öncelikle faz değişim malzemeli ısı değiştiricinin tasarımına ilişkin sayısal bir yöntem geliştirilmiş ve elde edilen sonuçlar daha önce yapılan analitik yöntemin sonuçları ile karşılaştırılmıştır. Daha sonra, faz değişim malzemeli ısı değiştiricinin hacmi sabit tutulmuş ve sistem üzerinde parametrik bir çalışma yapılmıştır. Boru aralığı değişimi, hava debisi (fan hızı) değişimi ve faz değişim malzemesi değişken parametreler olarak ele alınmıştır. Boru sayısı akışa dik yönde iki kat arttığında toplam ergime zamanı tüm dört aralık durumu için ortalama olarak %38 oranında azalmıştır

Saturated flow boiling heat transfer correlation for carbon dioxide for horizontal smooth tubes

WOS: 000401855700026Literature comprises fewer studies about flow boiling modelling of refrigerants for in tube flows. In addition, researches on two phase flow heat transfer are based on the mathematical models which were derived in a very limited operational condition and correlated for their own measurements. In this study, a new flow boiling model including the superposed effects of nucleate and convective boiling mechanisms is proposed through the minimization of the cumulative error between the proposed mathematical model and actual data by means of artificial cooperative search algorithm and applied to the database of R-744 (carbon dioxide), available from different studies in the literature. Predictions obtained from the proposed model have been compared with those of retained from the literature correlations developed for flow boiling in tubes. The comparison results indicate that the new model outperforms the literature correlations in terms of prediction accuracy. Results of the comparisons reveal that the proposed flow boiling mathematical model has a mean absolute relative error of 14.6% and predicts 76.7% of the experimental data within +/- 20.0%