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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 Türkistan’dan Tunceli’ye kurban inancı(Geleneksel Yayıncılık, 2017) Arslan, YusufToplumdan topluma kurbana yüklenen anlam, kurban kesim şekli, kurban sunuları değişiklik gösterse de, çoğunlukla her dinde ve gelenekte kurban, günahlardan arınma, tövbe, şükür gibi amaçlarla yapılmaktadır. 4000 yıllık bir tarihe sahip olan Türklerin gelenekleri incelendiğinde, kurban kesme ritüelinin eskiden beri sürdürüldüğü anlaşılmaktadır. İslamiyet’e dâhil olduktan sonra Türklerin kurban ritüellerinde bazı değişimler yaşanmıştır. Bazı ritüeller uygulamadan kalkarken bazıları yaşatılmıştır. Örneğin, eski Türklerde kurbanların başında gelen at, İslamiyet ile birlikte yerini koç, koyun, keçi, sığır gibi hayvanlara bırakmış ve at kurban etme geleneği unutulmuştur. Bununla birlikte, Şaman ayinlerinde kurban kesilmesi, mum yakılması geleneğinin Alevilerin cem ritüeli vesilesiyle olduğu gibi yaşatıldığı görülmektedir. Günümüzde, Aleviler arasında, eski Türk gelenek, görenek ve dinine ait motifler canlı şekilde izlenebilmektedir. Örneğin, Aleviler İslam’ı benimsemiş olmalarına karşın, İslam ile beraber eski Türklerin şaman/kam inancı, kopuz eşliğinde ibadet etme, sema, kadın/erkek bir arada ibadet etme, atalar kültü, dağ, ağaç ve nehirlere kutsallık atfetme biçimindeki inançlarını terk etmemişlerdir. İbadet dillerini de olduğu şekliyle, yani Türkçe olarak korumuşlardır. Alevilerin kurban ritüelleri, kimi değişimlere uğramışsa da, eski Türklerdeki birçok ritüeli bünyesinde korumuştur ve Aleviler yüzyıllardır eski Türk geleneklerindeki şekliyle kurbanlarını kesmişlerdir. Bu makalede, eski Türklerdeki kurban ritüelleriyle Tunceli Alevilerinin halk inançlarındaki kurban ritüeli karşılaştırılmış, benzerliklerin tespitine çalışılmıştır. Araştırma, nitel araştırma yöntemine göre gerçekleştirilmiştir. Araştırmanın verileri, 2015-2016 yıllarında Tunceli ve ilçelerinde, ziyaret yerlerinde yapılan yüz yüze mülakatlardan elde edilmiştir. Toplam görüşmeci sayısı sekiz olup görüşmeciler Tunceli il nüfusuna kayıtlıdır. Araştırmanın verileri, eski Türklerin kurban pratikleri ile Tunceli Alevilerinin kurban pratiklerinin dayandığı ortak bir geleneksel temel yapı olduğunu göstermiştir. Bir başka ifadeyle, Alevilerin kurban sunu/sungusu pratiklerinde, eski Türk geleneklerinin önemli oranda korunmuş olduğu anlaşılmıştır.Öğe Can hotel managers with social intelligence affect the emotions of employees?(Cogent OA, 2018-01-24) Genç, Volkan; Gülertekin Genç, SerayUsing the Multilevel Model of Emotional in Organizations, this study investigates whether managers’ levels of social intelligence affect employees’ emotional labor and the emotional climate of the workplace. In addition, the mediating effect of emotional labor on social intelligence and emotional climate is defined. A total of 276 surveys were distributed among the employees of a chain hotel in Istanbul. A structural equality modeling was used to explain the relationships between social intelligence, emotional labor, and emotional climate. The results reveal that social intelligence positively and significantly affects deep acting. It is also shown that social intelligence does not affect the emotional climate, and that emotional labor has no intermediary role. Practical results and recommendations are thus suggested for future research.Öğe Avro-Amerikan hegemonyası ve “Avrupalı bir yönetmen” olarak Lars von Trier(Uluslararası Kıbrıs Üniversitesi, 2017) Köksal, Selma; Denli, ÖzlemDanimarkalı film yönetmeni Trier’in filmografisi, hem konuları açısından, hem de artistik eğilimleri ile bize Avrupa Kültürü ve düşüncesi üzerine oldukça önemli veriler sunmakta, dünyamızın içinde bulunduğu düşünsel, kültürel, siyasi bunalım ve çıkmazlara, bir yanıyla modernlik eleştirisi de sayılabilecek, bir yorumla yaklaşmaktadır. Bu yazıdaki amacımız, Trier düşüncesinde ‘Avro-Amerikan’ kavramı olarak adlandırdığımız bu temanın izini sürmek; film kuramı ve siyaset bilimi disiplinlerinin bakış açısından analiz etmektir. Trier’in genelde Batı, özelde ise ‘Avro-Amerika’ uygarlığına yaklaşımının tartışılması bu yazının genel çerçevesini oluşturmaktadır. İncelediğimiz filmlerin altmetinleri olarak işaret ettiğimiz kolektif suç, kefaret ve insan doğası kavramları Trier’in ‘siyasal klostrofobi’sine işaret etmektedir. Yönetmen, tarihi daima geri dönen bir şiddet ve çöküş hikâyesi, insanı da yok olmaya mahkûm ve layık bir varlık olarak tasvir eder. Söz konusu temaların Trier sinemasının biçimsel unsurlarıyla ilişkisinin incelenmesi de yazının amaçları arasında yer almaktadır.Öğe Silica gel-immobilized 5-aminoisophthalohydrazide: A novel sorbent for solid phase extraction of Cu, Zn and Pb from natural water samples(Wiley Online Library, 2020-03-11) Aydın, Funda; Çakmak, Reşit; Levent, Abdulkadir; Soylak, MustafaA novel silica sorbent, silica gel‐immobilized 5‐aminoisophthalohydrazide (SiO2‐APH), was prepared by the condensation of 3‐chloropropyl‐functionalized silica gel with 5‐aminoisophthalohydrazide (APH) derived from dimethyl 5‐aminoisophthalate as a starting material and used for separation and preconcentration of Cu, Zn, and Pb metals in water samples using Flame Atomic Absorption Spectrometry (FAAS). The characterization of the new sorbent was carried out by Elemental Analysis, Thermogravimetric Analysis (TGA) and Fourier Transform Infrared Spectroscopy (FTIR). Important analytical parameters including as pH, amount of sorbent, type and amount of eluting solvent, sample volume, vortex and ultrasonic bath time, matrix ions that effect the developed SiO2‐APH‐solid phase extraction (SPE) method were investigated and optimum parameters were detected. Recoveries of examined metals were obtained as 98% for Cu and Pb and 101% for Zn. The relative standard deviation (RSD, n = 8) of Cu, Zn and Pb metals were 3.2, 2.8 and 1.6%, respectively. Limit of detections (LODs) (n = 10) were found as 2.7 μg L−1 for Cu, 7.4 μg L−1 for Zn and 3.5 μg L−1 for Pb μg L−1. The accuracy of the new method was assessed by analyzing of TMDA‐51.4 and TMDA‐70.2 certified reference materials. The results obtained for metals were in a good agreement with certified values. Addition/recovery test was applied to the real well, river, dam and stream water samples to check the accuracy of the method. The results showed that the developed SiO2‐APH‐SPE method can be effectively used as an alternative method for determination of Cu, Zn, and Pb metals in water samples.Öğe Voltammetric behavior of testosterone on bismuth film electrode: Highly sensitive determination in pharmaceuticals and human urine by square‐wave adsorptive stripping voltammetry(Wiley Online Library, 2015-03-20) Levent, Abdulkadir; Altun, Ahmet; Taş, Süleyman; Yardım, Yavuz; Şentürk, ZühreIn this paper, an electrochemical application of bismuth‐film electrode (BiFE) fabricated via ex‐situ electrodeposition onto a glassy carbon electrode for testosterone determination was investigated in aqueous and aqueous/surfactant solutions. In cyclic voltammetry, the compound showed one irreversible and adsorption‐controlled reduction peak. The BiFE revealed good linear response in the examined concentration range of 1 to 45 nmol L−1 testosterone in BrittonRobinson buffer, pH 5.0 containing 3 mmol L−1 cetyltrimethylammonium bromide. The limit of detection was 0.3 nmol L−1 (0.09 ng mL−1). Finally, the BiFE was satisfactorily applied for quantitation of testosterone in both pharmaceutical (oil‐based ampoule) and biological (human urine) samples.Öğe Investigation of experimental study of end milling of CFRP composite(De Gruyter, 2013-12-12) Çelik, Yahya Hışman; Kılıçkap, Erol; Yardımeden, AhmetCarbon fiber-reinforced plastic (CFRP) composites are materials that are difficult to machine due to the anisotropic and heterogeneous properties of the material and poor surface quality, which can be seen during the machining process. The machining of these materials causes delamination and surface roughness owing to excessive cutting forces. This causes the material not to be used. The reduction of damage and surface roughness is an important aspect for product quality. Therefore, the experimental study carried out on milling of CFRP composite material is of great importance. End milling tests were performed at CNC milling vertical machining center. In the experiments, parameters considered for the end milling of CFRP were cutting speed, feed rate, and flute number of end mill. The results showed that damage, surface roughness, and cutting forces were affected by cutting parameters and flute number of end mill. The best machining conditions were achieved at low feed rate and four-flute end mill.Öğe Coefficient bounds for a new subclass of analytic bi-close-to-convex functions by making use of Faber polynomial expansion(TÜBİTAK, 2017-07-25) Sakar, Fethiye Müge; Güney, Hatun ÖzlemRecently, in the literature, we can see quite a few papers about general coefficient bounds for subclasses of bi-univalent functions. However, we can find just a few papers about general coefficient estimates for subclasses of bi-close-to-convex functions. In the present study, we give and look into a new subclass of analytic and bi-close-to-convex functions in the open unit disk. Making use of the Faber series, we have an upper bound for the general coefficient of functions in this class. We also demonstrate the invisible behavior of the beginning coefficients of a special subclass of bi-close-to-convex functions.Öğe Estimate of cutting forces and surface roughness in end milling of glass fiber reinforced plastic composites using fuzzy logic system(Walter de Gruyter, 2014-06-01) Çelik, Yahya Hışman; Kılıçkap, Erol; Yardımeden, AhmetMilling glass fiber reinforced plastic (GFRP) composite materials are problematic, owing to, e.g., nonhomogeneous and anisotropic properties and effects of plastic deformation. To reduce these problems, the effects of cutting speed, feed rate, and the number of flutes on surface roughness and of thrust forces occurring during the milling of GFRP composite materials were investigated by both experimental and fuzzy logic models. Experiments were performed at 30 m/min, 60 m/min, and 90 m/min cutting speeds, at 0.1 mm/rev, 0.15 mm/rev, and 0.2 mm/rev feed rates and 10 mm diameters in a cemented carbide end mill, which has two, three, and four flutes without cutting fluids. The values obtained from experiments were defined by a fuzzy logic model. A fuzzy logic model was employed to estimate the surface roughness and thrust forces for different cutting parameters. As a result of both the experimental study and the fuzzy logic model, while the minimum thrust force was obtained at low cutting speeds, and feed rates and a high number of flutes end mill, the best surface quality was obtained at low feed rates, high cutting speed, and number of flutes end mill.Öğe A detailed biological and chemical investigation of 16 Achillea species’ essential oilsvia chemometric approach(Wiley-Blackwell, 2020-01-30) Yener, İsmail; Yılmaz, Mustafa Abdullah; Tokul Ölmez, Özge; Akdeniz, Mehmet; Tekin, Fetullah; Haşimi, Nesrin; Alkan, Mehmet Hüseyin; Öztürk, Mehmet; Ertaş, AbdulselamRepresentatives of the Achillea genus are widely used as foods or nutraceuticals. Considering the increasing demand for herbal dietary supplements with health promoting effects, the objective of this research was to evaluate the chemical composition and biological activities of the essential oils obtained from sixteen Achillea species ( A. biebersteinii, A. wilhelmsii subsp. wilhelmsii, A.aleppica subsp. zederbaveri, A. vermicularis, A. monocephala, A. nobilis, A. goniocephala , A. sintenisii , A. coarctata, A. kotschyi subsp. kotschyi, A. millefolium subsp. millefolium, A. lycaonica, A. spinulifolia, A. teretifolia, A. setacea, and A. schischkinii ). Anticholinesterase, antiurease, antityrosinase enzymes inhibition, antioxidant, antimicrobial, toxic and cytotoxic activities of obtained essential oils were investigated. DPPH activities were found to be very low in all studied samples, while ABTS and CUPRAC antioxidant activities were found to be moderate. In addition, all samples were found to have moderate anticholinesterase and antimicrobial effects. It has been determined that the studied species have low cytotoxicity and high toxicity. Besides, chemical composition of the essential oils were determined by GC-MS and the results were chemometrically analyzed. The chemometric analyses of Achillea species collected from 9 different regions were accomplished by principal component analysis (PCA) and hierarchical cluster analysis (HCA) techniques. According to the PCA analysis, A. nobilis subsp. neilreichii was found to be different from all studied species in terms of essential oil composition. The major components found in these species were piperitone, camphor, α-terpinene, eucalyptol, artemisia-ketone, endo-borneol, β-eudesmol and verbenol. The fact that, camphor being toxic and found in majority of the studied species, stands out as a remarkable result.
