AgInSe2 ve AgGaSe2 ince filmlerin ısısal buharlaştırma ve saçtırmalı kaplama teknikleriyle büyütülmesi ve n-CdS/p-AgGaSe2, p-Si/nAgInSe2 ve n-CdS/p-AgInSe2 pn-heteroeklem güneş hücrelerinin oluşturulması

TÜBİTAK TBAG15.06.2011Bu proje kapsamında, I-III-VI gurubu kalkopirit bileĢiklerinden olan AgInSe2 (AIS) ve AgGaSe2 (AGS) ince filmler üç farklı kaplama, ısısal (thermal), elektron demeti(e-beam) ve DC/RF manyetik saçtırmalı (sputtering) buharlaştırma yöntemleri kullanılarak üretilmiştir. Projenin ilk aşamasında, cam tabanlar üzerinde kaplanan filmlerin elektriksel, optik, yapısal ve yüzeysel özellikleri XRD, SEM, EDS ve XPS ölçümleri alınarak belirlenmiş ve büyütme koşulları optimize edilmiştir. Isısal ve elektron demeti yöntemiyle kaplama için, buharlaştırmada kullanılacak kaynak malzeme saf Ag, In, Ga ve Se elementleri istenilen oranda kuvartz tüpler içerisine istenen içerikte yerleştirilip, vakumlanarak Bridgman kristal çekme sistemiyle AgInSe2 ve AgGaSe2 kristalleri sentezlenmiş ve buharlaştırma kaynağı olarak kullanılmıştır. Üçüncü olarak ise daha önce çok fazla uygulanmamış olan, RF/DC manyetik saçtırma tekniğiyle, AgInSe2 ve AgGaSe2 ince fılmler katmanlar halinde farklı kalınlıklarda, aynı vakum ortamında, vakumu bozmadan üç kaynaklı saçtırmalı buharlaştırma sistemi kullanılarak, farklı alttaşlar üzerine katmanlar halinde Ag/InSe/Ag... kaplanmış, sonrasında üçlü bileşik yapısının oluşması için filmlerin 200-500 oC derece arasında tavlanmıştır. Ayrıca kaplama ve tavlama sırasında yapı içerisindeki Se ayrışmasını ortadan kaldırmak için baĢka bir sistemde selenyum atmosferinde 300-500 oC‟de, 30 dakika tavlanmıştır. Çalışmanın takip eden son aşamasında her üç yöntemle hazırlanan ince filmler kullanılarak; Mo/p-AgInSe2, p-Si/n-AgInSe2, n-CdS/p-AgInSe2, Mo/n-AgGaSe2/p-AgInSe2, gibi farklı pn-heteroeklem ve metal/yarıiletken aygıt yapıları oluşturularak, karanlık ve aydınlık akım-voltaj (I-V), farklı frekanslarda kapasitans-voltaj(C-V) ve 400-1200 nm arasında spektral fotoakım ölçümleri alınarak aygıt parametreleri tespit edilmiştir. Ayrıca güneş benzeticisi kullanılarak AM1 şartlarında verimlilikleri ölçülmüştür.In the scope of this project, the members of I-III-VI groups of ternary chalcogonide compounds, namely AgInSe2 (AIS) and AgGaSe2 (AGS) thin films have been deposited by means of thermal evaporation, e-beam and RF/DC magnetron sputtering deposition techniques. In the first part of the project, electrical, optical, structural and morphological properties of thin films deposited on glass substrates by taking XRD, SEM, EDS and XPS measurements were analyzed and the growth conditions were optimized. The evaporation source material for thermal and e-beam deposition methods were prepared by mixing and placing the desired molecular content of pure Ag, Ga, In and Se elements into quartz ampoule and sealing it under vacuum. Then, the ampoule was placed through Brigdman crystal system to produce the single crystals of AgInSe2 and AgGaSe2, and they were used as the evaporation source in these methods. RF/DC magnetron sputtering was used as third evaporation method, which is not used so frequently in this kind of study. By using this method, AgInSe2 and AgGaSe2 were deposited on different substrates, especially on glass substrates layer by layer growth of each Ag, InSe and GaSe targets in different thickness and sequences such as Ag/InSe/Ag...Then, deposited films were annealed at the same chamber under vacuum in the range of 200-500 oC in order to form ternary compounds by controlling the diffusion of the constituent elements. Also, the grown thin films were annealed under selenium atmosphere in between 300 and 500 oC for 30 min. in another vacuum chamber to compensate the Se segregation. In the final part of this study, the thin films deposited by these three techniques were used to produce different np- or pn-heterojunction and metal/semiconductor device structure Mo/p-AgInSe2, p-Si/n-AgInSe2, n-CdS/p-AgInSe2, Mo/n-AgGaSe2/p-AgInSe2, and their dark and illuminated current-voltage (I-V), capacitance- voltage(C-V) at different frequencies and spectral-photocurrent in the wavelength range of 400-1200 nm were measured and their device parameters were investigated. The solar efficiency of the devices with the solar simulator under AM1 condition was also measured

A discrete host-parasitoid model with development of pesticide resistance and IPM strategies

The development of pesticide resistance significantly affects the outcomes of pest control. A quantitative depiction of the effects of pesticide resistance development on integrated pest management (IPM) strategies and pest control outcomes is challenging. To address this problem, a discrete host-parasitoid model with pesticide resistance development and IPM strategies is proposed and analyzed. The threshold condition of pest eradication which reveals the relationship between the development of pest resistance and the rate of natural enemy releases is provided and analyzed, and the optimal rate for releasing natural enemies was obtained based on this threshold condition. Furthermore, in order to reduce adverse effects of the pesticide on natural enemies, the model has been extended to consider the spraying of pesticide and releases of natural enemies at different times. The effects of the dynamic complexity and different resistance development equations on the main results are also discussed

Yerfıstığı Üretiminde Enerji Kullanım Etkinliğinin Belirlenmesi (Adana ili örneği)

Bu çalışmada, 2017 yılında Adana koşullarında yetiştirilen yer fıstığı üretiminin enerji bilançosu ortaya konulmuştur. Çalışmada kullanılan alet-makinelerin ekonomik ömürleri, iş başarısı, yakıt-yağ tüketimleri, makine ağırlıkları ile gübre, tohum miktarları gibi temel veriler, mevcuttaki yapılan ölçümlerden, yapılan diğer çalışmalardan, çeşitli kaynak ve kataloglardan temin edilmiştir. Yapılan değerlendirmeler sonucunda yer fıstığı üretiminde enerji çıktı/girdi oranı 1.94, özgül enerji değeri 12.90 MJ kg-1, enerji üretkenliği 0.08 kgMJ-1, net enerji verimi 52734.28 MJ ha-1 olarak hesaplanmıştır. Yer fıstığı üretiminde toplam enerji girdileri içerisinde kullanım oranı en yüksek olan % 48.69 ile sulama enerjisi olduğu bulunmuştur. Bunu sırasıyla % 22.31 ile yakıt-yağ enerjisi, % 14.90 ile gübre enerjisi, %5.78 ile tohum enerjisi, % 5.58 ile ilaç enerjisi, % 2.59 ile makine enerjisi ve % 0.16 ile insan enerjisi takip etmiştir

Moisture dependent of some physical and morphological properties of dent corn (Zea mays var. indentətə Sturt) seeds

In this study, physical properties of seeds of Simon and Goldeclat dent corn (Zea mays var. indentətə sturt) cultivars as a function of moisture content were evaluated. Three levels of moisture ranging from 12.76 to 17.0% (dry basis), and 11.09 to 16.48% (dry basis) were used for Simon and Goldeclat cv., respectively. The averaged length, width, thickness, arithmetic and geometric mean diameter of seeds ranged from 10.54, 7.26, 4.57, 116.46 and 7.04 mm for Simon cv.; 10.80, 6.89, 4.81, 119.42 and 7.09 mm for Goldeclat cv., respectively. The sphericity, volume and surface area increased linearly from 0.668 to 0.684, 125.94 to 162.51 mm3, 131.13 to 154.37 mm2 for Simon cv.; 0.657 to 0.670, 128.19 to 155.63 mm3, 133.18 to 150.89 mm2 for Goldeclat cv., respectively. The bulk densities decreased from 762.60 to 675.51 kg/m3 and from 783.37 to 714.48 kg/m3 and true densities decreased from 1425.07 to 1367.35 kg/m3 and from 1455.0 to 1396.36 kg/m3 for Simon and Goldeclat cv., respectively, whereas, the angle of repose increased from 23.50 to 26.65° band from 21.86 to 25.27°. The static coefficients for friction of dent corn seeds were determined steel, plywood, wood, glass and galvanized sheet at various moisture contents. The highest static coefficient of friction was found on the wood and the lowest on the glass sheet among the materials tested.Key words: Dent corn, physical properties, moisture content, dimensions, density

Nohut Üretiminde Enerji Kullanım Etkinliği ve Sera Gazı (GHG) Emisyonunun Belirlenmesi (Adana ili örneği)

Bu çalışmada, 2017 yılında Adana koşullarında yetiştirilen nohut üretiminin enerji bilançosunun oluşturulması ve sera gazı (GHG) emisyonunun belirlenmesi amaçlanmıştır. Çalışmada kullanılan alet-makinelerin ekonomik ömürleri, iş başarısı, yakıt-yağ tüketimleri, makine ağırlıkları ile gübre, tohum miktarları gibi temel veriler, mevcuttaki yapılan ölçümlerden, yapılan diğer çalışmalardan, çeşitli kaynak ve kataloglardan temin edilmiştir. Yapılan değerlendirmeler sonucunda nohut üretiminde enerji çıktı/girdi oranı 1.82, özgül enerji değeri 9.99 MJ kg-1, enerji üretkenliği 0.10 kgMJ-1, net enerji verimi 8319.86 MJ ha-1 olarak hesaplanmıştır. Nohut üretiminde toplam enerji girdileri içerisinde en yüksek kullanım oranı % 35.59 ile yakıt-yağ enerjisinde olduğu bulunmuştur. Bunu sırasıyla % 24.63 ile gübre enerjisi, %23.49 ile tohum enerjisi, % 8.43 ile makine enerjisi, % 7.61 ile ilaç enerjisi ve % 0.24 ile insan enerjisi takip etmiştir. Nohut üretimi için toplam GHG emisyonu 1638.85 kgCO2-eşha-1 olarak hesaplanmıştır. Toplam GHG emisyonları içerisinde en yüksek pay tohuma (%60.52) aittir. Tohumu sırasıyla dizel yakıt tüketimi (%17.56), azotlu gübre kullanımı (%8.37), fosfatlı gübre kullanımı (%4.32), makine kullanımı (%3.69), fungusit kullanımı (%2.62), herbisit kullanımı (%2.47) ve insan işgücü (%0.46) takip etmiştir. Buna ilave olarak, nohut üretiminde GHG oranı 1.62 kgCO2-eşkg-1 olarak hesaplanmıştır

Mathematical calculation and experimental investigation of expanded perlite based heat insulation materials' thermal conductivity values

DURMUS, Gokhan/0000-0002-8827-7041; Agbulut, Umit/0000-0002-6635-6494; KARAAGAC, IBRAHIM/0000-0001-6727-3650WOS: 000437194500003Thermal resistance can be increased by using proper heat insulation materials. Traditional heat insulation materials do not stand all desired properties. Thus, developing new heat insulation materials is very important. In this study, expanded perlite based heat insulation material was developed as an alternative to the traditional insulation materials. The composition of the developed material was designed and prepared using the theoretical thermal conductivity prediction models. The prepared material was molded in a rectangular shape panel. Thermal conductivities of panels were measured experimentally and the results were compared with the calculated results. Also, the results showed that the developed panels can be used for heat insulation applications. On the other hand, the closest model to the experimental results is the parallel model whose average deviation is 4.22% while the farthest model is the Cheng and Vachon model whose average deviation is 12.43%. It is obtained that parallel and series models are generally in good agreement with the experimental results. Nevertheless, it is seen some deviations between experimental and theoretical calculation results. The theoretical prediction models do not include any processing conditions such as molding and curing. It is thought that these deviations have originated because of the missing processing parameters in theoretical prediction models. As a result of experimental studies, the lowest thermal conductivity value of expanded perlite based panels was obtained 43.5 mW/m.K. Consequently, the heat transfer coefficient of the panels containing expanded perlite can be calculated nearly by the parallel method.Scientific and Technological Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [115M041]; TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK)This study was supported by the Scientific and Technological Research Council of Turkey (Project no: 115M041). We are indebted to TUBITAK for its financial support

Mathematical calculation and experimental investigation of expanded perlite based heat insulation materials' thermal conductivity values

Thermal resistance can be increased by using proper heat insulation materials. Traditional heat insulation materials do not stand all desired properties. Thus, developing new heat insulation materials is very important. In this study, expanded perlite based heat insulation material was developed as an alternative to the traditional insulation materials. The composition of the developed material was designed and prepared using the theoretical thermal conductivity prediction models. The prepared material was molded in a rectangular shape panel. Thermal conductivities of panels were measured experimentally and the results were compared with the calculated results. Also, the results showed that the developed panels can be used for heat insulation applications. On the other hand, the closest model to the experimental results is the parallel model whose average deviation is 4.22% while the farthest model is the Cheng and Vachon model whose average deviation is 12.43%. It is obtained that parallel and series models are generally in good agreement with the experimental results. Nevertheless, it is seen some deviations between experimental and theoretical calculation results. The theoretical prediction models do not include any processing conditions such as molding and curing. It is thought that these deviations have originated because of the missing processing parameters in theoretical prediction models. As a result of experimental studies, the lowest thermal conductivity value of expanded perlite based panels was obtained 43.5 mW/m. K. Consequently, the heat transfer coefficient of the panels containing expanded perlite can be calculated nearly by the parallel method. © 2018 Yildiz Technical University