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Öğe N-type InP Schottky diodes with organic thin layer: Electrical and interfacial properties(Journal of Vacuum Science & Technology B, 2010-03) Güllü, Ömer; Turut, AbdulmecitThe rectifying junction characteristics of methyl red (MR) organic film on n-type InP substrate have been studied. It has been observed that MR-based structure shows an excellent rectifying behavior and that the MR film increases the effective barrier height by influencing the space charge region of the n-type InP. The barrier height and ideality factor values for this structure have been obtained as 0.75 eV and 1.93 from the forward bias current-voltage characteristics, respectively. By using capacitance-voltage characteristics at 1 MHz, the barrier height and the carrier concentration values have been calculated as 0.93 eV and 5.13×1015 cm−3, respectively. The energy distributions of the interface states and their relaxation times have been determined from the forward bias capacitance-frequency and conductance-frequency characteristics. Moreover, it was seen that both the interface-state density and the relaxation time of the interface states decreased with bias voltage from experimental results.Öğe A general view to political and economic events causing the collapse of Mamluk State(Energy Education Science&Technology, Part B, 2012-04) Ağır, Abdullah Mesut; Solak, Kemal; Şen, Mehmet Emin; Platin, İhsann this manuscript, the collapse of Mamluk State, which reigned in Egypt and Syria between the years 1250 and 1517 has been studied. Throughout our study, there found different reasons causing this collapse; the most important ones of which are political and economic. The fact that Mamluk System which had crucial role in Mamluk administration Mechanism and the problems lived along its north border are the fundamental collapsing reasons of the state. Indeed, the fights starting with Mongols and Armenians in the north of the state continued with Anatolian Turkmens and Timurids, eventually Ottomans coming from the same direction caused it to be collapsed. Mamluks were the commercial centre between east and west. At the same time, Syria owned a very industrious trade network between Anatolia. However, the geographical discoveries that Europeans carried out and the Portuguese not only military but also commercial activities in the Indian Ocean weakened Mamluks economically. In addition to this, military struggles along the north border of the state caused incompensable deficits in Mamlûk finance. Consequently, when all these negative aspects combined with an unmodernized army, Mamlûk State closed its era in 1517, when Ottoman army defeated it in Reydaniye, which was the end of a 267 year-old-state.Öğe Performance and exhaust emissions of a DI diesel engine fueled with waste cooking oil and inedible animal tallow methyl esters(TÜBİTAK, 2011) Altun, ŞehmusThe performance and exhaust emissions of a direct injection diesel engine were experimentally investigated using 2 biodiesel fuels with promising economic perspective, one obtained from inedible animal tallow and the other from waste cooking oils. Inedible animal tallow, which is obtained from a mixture of slaughtered cattle and sheep fats collected from a local slaughterhouse during meat preparation process, was transesterified using methyl alcohol and an alkaline catalyst to produce the inedible animal tallow methyl ester. Biodiesel from waste cooking oil was produced from waste cooking oils and methyl alcohol via a transesterification reaction, and provided by a commercial biodiesel producer. In order to investigate the performance and exhaust emissions, the experiments were conducted at different engine speeds under the full load condition of the engine. The experimental results showed, compared with diesel fuel, that the biodiesel fuels resulted in a reduction in brake torque and in an increase in brake specific fuel consumption. Although both biodiesels caused reductions in carbon monoxide (CO), the NOx emissions were higher for waste cooking oil biodiesel and lower for inedible animal tallow biodiesel as compared to diesel fuel.Öğe Laws doku enerji ölçümü tabanli k-NN siniflandirici modeli ile iris tanima sistemi(IEEE, 20013-06-13) Acar, Emrullah; Özerdem, Mehmet SiraçBiyometrik tanıma teknolojisi genellikle çok pahallı ve son derece önemli güvenlik uygulamaları ile ilişkili olmuştur.İris tanıma sistemi, etkili biyometrik tanımasistemlerinden biridir. Bu çalışmada, farklı insanlardan elde edilen gözimgelerininiçerdiği irisdokuözelliklerinegörekişilerin tanınmasıamaçlanmıştır. İmgeler CASIAiris veritabanındanelde edilmiştir. İmge dokusuna duyarlı yeni yöntemlerdenbiri olanLawsDoku Enerji Ölçümü (Laws TEM) kullanılarak, iris dokusunun belirli yerelalanlarındanöznitelik vektörleri elde edilmiştir. kEn Yakın Komşu (k-NN) sınıflandırıcıparametrelerinden komşu sayısı(k) farklı değerlerde alınarak, elde edilen öznitelik vektörleri k-NN sınıflandırıcısı ile ayrıştırılmıştır. Farklı komşu sayılarına göre sisteminperformans değerlerikarşılaştırılmıştır. Sonuç olarak en yüksek ortalama performans,k-NNsınıflandırıcısınınk=1ve 2komşularıyapısında % 80.74olarak gözlemlenmiştir.Öğe Performance and emission evaluation of a CI engine fueled with preheated raw rapeseed oil (RRO)–diesel blends(Journals & Books, 2010-03) Aydın, Hüseyin; Hanbey, HazarMany studies are still being carried out to find out surplus information about how vegetable based oils can efficiently be used in compression ignition engines. Raw rapeseed oil (RRO) was used as blended with diesel fuel (DF) by 50% oil–50% diesel fuel in volume (O50) also as blended with diesel fuel by 20% oil–80% diesel fuel in volume (O20). The test fuels were used in a single cylinder, four stroke, naturally aspirated, direct injection compression ignition engine. The effects of fuel preheating to 100 °C on the engine performance and emission characteristics of a CI engine fueled with rapeseed oil diesel blends were clarified. Results showed that preheating of RRO was lowered RRO’s viscosity and provided smooth fuel flow Heating is necessary for smooth flow and to avoid fuel filter clogging. It can be achieved by heating RRO to 100 °C. It can also be concluded that preheating of the fuel have some positive effects on engine performance and emissions when operating with vegetable oil.Öğe Dimension and insulation thickness optimization of circular flat plate solar collectors(Energy Education Science and Technology, 2011) Argunhan, ZekiIn this study, expressions for optimum radius of a circular flat plate solar collector and the optimum insulation thickness distribution are derived by using the concept of solar gain, which maximizes the life-cycle savings. For the specified condition the optimum radius has been found as 2.14 m and the optimum insulation thickness distribution on back of collectors has been formulized. The insulation material thickness distribution has been determined by performing a detailed dimensional analysis; therefore heat loss is minimized, and results are presented in graphics.Öğe The effects of injection pressure on the engine performance characteristics of a CI engine fueled with canola oil-diesel blends(Energy Education Science and Technology Part A: Energy Science and Research, 2012-01) Aydın, HüseyinThe usage of vegetable oils in diesel engines has some negative effects especially on engine performance. Therefore vegetable oils can not be used as pure form or with high percentages in diesel fuel in unmodified diesel engines. Some of the engine operation conditions should be improved by modifying engine operation systems for this purpose. The effects of injection pressure on engine performance of a diesel engine, by using two different blends of vegetable oil (canola oil) in diesel fuel (DF) having a concentration of 20% (O20) and 50% (O50) vegetable oil, were studied in the present work. The injection pressure was changed from 200 MPa to 220 MPa. Tests were made at fully loaded engine and different speeds of engine operation. In the experiments, the engine power, torque, brake specific fuel consumption (Bsfc), mass fuel consumption rate, brake thermal efficiency and exhaust gas temperature of the test engine have been investigated. Results revealed that the increased injection pressure can significantly promote performance parameters of diesel engine with using vegetable oil without any modification either in oil or in engine itself. The improved results of experiments have been given as graphics in this paper.Öğe Determination of performance and exhaust emissions properties of B75 in a CI engine application(Journals & Books, 2011-09) Aydın, Hüseyin; İlkılıç, CumaliIn this study, performance and exhaust emissions of biodiesel in a compression ignition engine was experimentally investigated. Therefore, biodiesel has been made by transesterification from cotton seed oil and then it was mixed with diesel fuel by 25% volumetrically, called here as B75 fuel. B75 fuel was tested, as alternative fuel, in a single cylinder, four strokes, and air-cooled diesel engine. The effect of B75 and diesel fuels on the engine power, engine torque and break specific fuel consumption were clarified by the performance tests. The influences of B75 fuel on CO, HC, NOx, Smoke opacity, CO2, and O2 emissions were investigated by emission tests. The engine torque and power, for B75 fuel, were lower than that of diesel fuel in range of 2–3%. However, for the B75, specific fuel consumption was higher than that of diesel fuel by approximately 3%. CO2, CO, HC, smoke opacity and NOx emissions of B75 fuel were lower than that of diesel fuel. The experimental results showed that B75 fuel can be substituted for the diesel fuel without any modifications in diesel engines.Öğe Memlûk Sultanlarının gölgesi altında Hilâfet kurumu(Gaziantep Üniversitesi, 2011-04) Ağır, Abdullah Mesutİlhanlıların 1258 yılında Bağdat‟ı ele geçirip Abbâsî Devletini ortadan kaldırmalarından sonra Türk-İslâm âlemi için büyük önem taşıyan hilâfet makamı üç yıl boyunca tarih sahnesinde görünmeyecekti. Memlûkların Moğollara karşı 1260‟da kazandıkları siyasî zafer Müslümanları büyük bir sevince boğarken, Sultan Baybars‟ın 1261 yılında hilâfeti Kahire‟de yeniden ihdâs etmesi, onların İslâm âlemi üzerindeki saygınlıklarının artmasını sağladı. Fakat Kahire‟de ihdâs edilen halifelik, Bağdat Abbâsî halifeliğinden büyük farklılıklar arz ediyordu. Sultanların gölgesi altında kalmış, hiçbir siyasî yetkisi ve otoritesi bulunmayan, topraksız ve sadece kendisine az bir miktar maaş bağlanan halifeler, birkaç istisna dışında, bu durumlarını Memlûkların sonu olan 1517 senesine kadar sürdüreceklerdi.Öğe Recognition of daily and sports activities(IEEE, 201-01-24) İnanç, Nihat; Kayri, Murat; Ertuğrul, Ömer FarukSince being physically inactive was reported as one of the major risk factor of mortality, classifying daily and sports activities becomes a critical task that may improve human life quality. In this paper, the daily and sports activities dataset was used in order to evaluate and validate the employed approach. In this approach, the statistical features were extracted from the histograms of the local changes in the wearable sensors logs were obtained by one-dimensional local binary patterns. Later, extracted features were classified by extreme learning machines. Results were showed that the proposed approach is enough to recognize the action type, but in order to recognize the actions, or gender, different feature extraction methods must be employed.
