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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 Numerical and experimental investigation of solar chimney power plant system performance(Taylor & Francis, 2020-03-15) Karakaya, Hakan; Durmuş, Aydın; Avcı, Ali SerkanA prototype of a solar chimney power plant was performed by modeling in this study. The performed prototype was experimentally confirmed. Temperature, velocity, and radiation values were measured to actualize the confirmation. Experimental data that were obtained to determine the performance of solar chimney whose prototype was actualized by the help of measured values were computationally analyzed. The geometry of a solar chimney in the analysis was bidimensionally (2D) drawn on an axis of symmetry. The numerical simulation was analyzed with computational fluid dynamics (CFD) method. Since analysis results show that there is turbulent flow in system (RNG), k-ɛ turbulence model was used. Continuity, momentum, and energy equations were applied to the solar chimney system via the finite volume method. Moreover, DO (discrete ordinates) model was inserted in analysis to evaluate the radiation effect in the collector area. In addition to all these, correlation results between SPSS 17 statistics program and data obtained were evaluated. Finally, with reference to the comparison between numerical and experimental results, data obtained and numerical data are close to each other; the prototype is applicable to the real systems.Öğe Küllüoba’da İlk Tunç Çağı'nda beslenme alışkanlıkları ve bölgesel karşılaştırması(Arkeoloji ve Sanat, 2019) Gündem, Can YumniÖğe Effects of particle reinforcement on the bending and compressive behaviors of composite pipes(Materials Testing, 2019-11) Adin, HamitIn this study, the effects of adding particles to composite pipes were examined. For the study, composite pipes reinforced with particles were produced by using structural epoxy adhesive and mica as the particle. Composite pipes oriented at [-45 °/+45 °] were manufactured by the hand lay-up method. The composite pipes were loaded axially for measuring bending and compressive strength. When bending and compression loads are applied in the experiments it was seen that the particle reinforced methods indicated in the literature have a great effect of on the strength of the bending and compressive behaviour. The results show that addition of particles enhances compressive and bending strength.Öğe Milling Inconel 718 workpiece with cryogenically treated and untreated cutting tools(SpringerLink, 2021-07-17) Gürbüz, Hüseyin; Baday, ŞehmusAlthough Inconel 718 is an important material for modern aircraft and aerospace, it is a kind material, which is known to have low machinability. Especially, while these types of materials are machined, high cutting temperatures, BUE on cutting tool, high cutting forces, and work hardening occur. Therefore, in recent years, instead of producing new cutting tools that can withstand these difficult conditions, cryogenic process, which is a heat treatment method to increase the wear resistance and hardness of the cutting tool, has been applied. In this experimental study, feed force, surface roughness, vibration, cutting tool wear, hardness, and abrasive wear values that occurred as a result of milling of Inconel 718 material by means of cryogenically treated and untreated cutting tools were investigated. Three different cutting speeds (35-45-55 m/min) and three different feed rates (0.02- 0.03-0.04 mm/tooth) at constant depth of cut (0.2 mm) were used as cutting parameters in the experiments. As a result of the experiments, lower feed forces, surface roughness, vibration, and cutting tool wear were obtained with cryogenically treated cutting tools. As the feed rate and cutting speed were increased, it was seen that surface roughness, vibration, and feed force values increased. At the end of the experiments, it was established that there was a significant relation between vibration and surface roughness. However, there appeared an inverse proportion between abrasive wear and hardness values. While BUE did not occur during cryogenically treated cutting tools, it was observed that BUE occurred in cutting tools which were not cryogenically treated. Also, in this study, the statistical validity of the experimental values was tested with the help of secondorder equations and analyses of variance (ANOVA). R2 values obtained as 99.14%, 99.76%, and 97.98% for vibration, surface roughness, and feed force values were modeled statistically with the help of second-order equations, respectively.Öğe Al/Nigrosin/p-Si yapıların fabrikasyonu ve temel diyot parametrelerinin hesaplanması(Dicle Üniversitesi, 2018-09-25) Güllü, ÖmerBu çalışmada π bağları açısından zengin organik molekülün (Nigrosin (NIG)) optik özellikleri UV-Vis yöntemiyle belirlendi. Cam altlık üzerinde damlatma yöntemi ile büyütülen NIG ince tabakasının direkt yasak enerji değerleri; 1,42 eV (Q bandı) ve 2,94 eV (B bandı) olarak rapor edildi. Oluşturulan referans Al/p-Si ve Al/NIG/p-Si Metal/Organik aratabaka/Yarıiletken (MIS) yapılarının I-V ölçümleri sonunda tüm yapıların doğrultucu özelliğe sahip oldukları gözlemlendi. Oda sıcaklığında alınan I-V ölçümleri kullanılarak yapıların karakteristik diyot özellikleri belirlendi. Burada Al/NIG/p-Si diyotunun kapasitör özelliği, C-V ölçümleri alınarak incelendi ve yapılan hesaplamalar sonucunda bazı diyot parametreleri elde edildi. Elde edilen sonuçlar, π bağları açısından zengin olan NIG gibi organik malzemelerin elektronik sahasında kullanılabileceğini gösterdi.Öğe Assessment of heavy metal pollution of urban soils of Batman by multiple pollution indices(Taylor & Francis, 2021-03-28) Baran, Hacı Alim; Gümüş Kıral, NurcanHeavy metal accumulation is observed in urban soils, sometimes due to anthropological effects and sometimes due to natural geological units. In order to determine the heavy metal content of the Upper MioceneLower Pliocene Selmo Formation, which is observed in the whole study area and consists of conglomerate, sandstone and silt stone, soil and river sediment samples were taken. Within the scope of pollution assessment, geo-accumulation index (Igeo), enrichment factor (EF) and pollution index (PI) calculations of Batman urban soil samples were made and different degrees of pollution values were determined. High pollution values were obtained for As, Mo and Sb elements in all pollution indices calculated. The pollution levels of the three elements were determined as strongly to extremely contaminated according to Igeo values, the others except As (very severe enrichment) according to EF values were determined as severe enrichment, and according to PI, all three were determined as strong polluted. Pollution and element distribution maps were created with a geographical information system software. According to the results of correlation analysis and cluster analysis, the elements found to be contaminated are divided into two groups, whose locations and sources of contamination are different. The first group (Sn, Zn and Pb) is observed in the approximate centre of the study area and developed due to traffic emissions. The elements belonging to the second group (especially As, Mo and Sb) show high pollution values in the south-southeast of the study area. These pollutions are thought to be caused by the inadequate storage of mineral oils and batteries that are changed in the industrial site and from leaks in the oil production, storage, refining and transmission phase in TPAO, TÜPRAŞ and BOTAŞ. The analysed samples were compared with the Soil Pollution Control Regulation and WHO standards, and Co, Ni and As element values were found to exceed the permissible values for healthÖğe Dijital ebeveynlik farkındalık ölçeğinin geliştirilmesi(İnönü Üniversitesi, 2020-06-04) Manap, Abdullah; Durmuş, EmineBu araştırmanın amacı, keşfedici sıralı desen modeline göre dijital ebeveynlik farkındalığının boyutlarını belirlemek ve anne babaların dijital ebeveynlik farkındalık düzeyine ilişkin geçerli ve güvenilir bir ölçek geliştirmektir. İlk basamakta nitel görüşmelerin içerik analizi ile dijital ebeveynlik farkındalığının boyutları belirlenmiştir. İkinci aşamada, anne-babaların dijital ebeveynlik farkındalığını belirleyen bir ölçek geliştirilmiştir. Nitel bulgulara göre; dijital ebeveynlik farkındalığının beş boyutlu olduğu sonucuna varılmıştır. Nitel çalışma sonuçları ve alan yazı incelenerek bir madde havuzu oluşturulmuştur. Sonraki aşamada geçerlik ve güvenirlik analizleri yapılan ve ebeveynlerin dijital farkındalığını ölçmeyi amaçlayan bir ölçek geliştirilmiştir. Ölçek geliştirme aşamasında ölçeğin yapı geçerliği için ilkokula giden çocuğa sahip 461 ebeveyn üzerinden açımlayıcı faktör analizi yapılmıştır. Farklı 291 ebeveyn üzerinden doğrulayıcı faktör analizi gerçekleştirilmiştir. Ölçeğin güvenirliğine ilişkin iç tutarlılık katsayıları, test yarılama analizi, madde analizleri ve son olarak ölçüt geçerliği bulguları elde edilmiştir. Araştırma sonunda, geçerlik ve güvenirliği test edilmiş, , dört boyutlu ve 16 maddelik bir “Dijital Ebeveynlik Farkındalık Ölçeği” geliştirilmiştir. Bu araştırmanın sonuçlarına göre Dijital Ebeveynlik Farkındalık Ölçeği’nin alt boyutları ile nitel bulguları karşılaştırıldığında elde edilen bulguların birbirini desteklediği görülmektedir. Nitel bulguların alt temaları; verimli kullanım, risklerden koruma, model olma, dijital ihmal ve yeniliklere açık olma şeklindedir. Ölçeğin alt boyutlarının da; verimli kullanım, risklerden koruma, model olma ve dijital ihmal şeklinde olduğu görülmektedir. Ölçek de yer alan alt boyutlarla ebeveynlerin dijital ebeveynlik farkındalığının belirlenebileceği görülmektedir.Öğe Electrical analysis of organic dye based MIS Schottky contacts(Microelectronic Engineering, 2010-05-25) Güllü, Ömer; Turut, AbdulmecitIn this work, we prepared metal/interlayer/semiconductor (MIS) diodes by coating of an organic film onp-Si substrate. Metal(Al)/interlayer(Orange G@OG)/semiconductor(p-Si) MIS structure had a good recti-fying behavior. By using the forward-biasI–Vcharacteristics, the values of ideality factor (n) and barrierheight (BH) for the Al/OG/p-Si MIS diode were obtained as 1.73 and 0.77 eV, respectively. It was seen thatthe BH value of 0.77 eV calculated for the Al/OG/p-Si MIS diode was significantly larger than the value of0.50 eV of conventional Al/p-Si Schottky diodes. Modification of the potential barrier of Al/p-Si diode wasachieved by using thin interlayer of the OG organic material. This was attributed to the fact that the OGorganic interlayer increased the effective barrier height by influencing the space charge region of Si. Theinterface-state density of the MIS diode was found to vary from 2.79x1013to 5.80x1012eVx1cmx2.Öğe Magnetite nanoparticles grafted with murexide-terminated polyamidoamine dendrimers for removal of lead (II) from aqueous solution: synthesis, characterization, adsorption and antimicrobial activity studies(Journals & Books, 2021-03) Ekinci, Selma; İlter, Zülfiye; Ercan, Selami; Çınar, Ercan; Çakmak, ReşitIn this study, new, efficient, eco-friendly and magnetically separable nanoadsorbents, MNPs-G1-Mu and MNPs-G2-Mu, were successfully prepared by covalently grafting murexide-terminated polyamidoamine dendrimers on 3-aminopropyl functionalized silica-coated magnetite nanoparticles, and used for rapid removal of lead (II) from aqueous medium. After each adsorption process, the supernatant was successfully acquired from reaction mixture by the magnetic separation, and then analyzed by employing ICP-OES. Chemical and physical characterizations of new nanomaterials were confirmed by XRD, FT-IR, SEM, TEM, and VSM. Maximum adsorption capacities (qm) of both prepared new nanostructured adsorbents were compared with each other and also with some other adsorbents. The kinetic data were appraised by using pseudo-first-order and pseudo-second-order kinetic models. Adsorption isotherms were found to be suitable with both Langmuir and Freundlich isotherm linear equations. The maximum adsorption capacities for MNPs-G1-Mu and MNPs-G2-Mu were calculated as 208.33 mg g−1 and 232.56 mg g−1, respectively. Antimicrobial activities of nanoparticles were also examined against various microorganisms by using microdilution method. It was determined that MNPs-G1-Mu, MNPs-G2-Mu and lead (II) adsorbed MNPs-G2-Mu showed good antimicrobial activity against S. aureus ATTC 29213 and C. Parapsilosis ATTC 22019. MNPs-G1-Mu also showed antimicrobial activity against C. albicans ATTC 10231.
