Investigation of mechanical, elastic and thermodynamic properties of Ni2VAl compound

Bu çalışmada teknolojik öneme haiz Heusler ailesinden Ni2VAl bileşiğinin yapısal, mekanik ve termo dinamik özellikleri ilk prensipler yöntemi ile teorik olarak incelenmiştir. Öncelikle bileşiğin temel durumunu ve en düşük enerji seviyesini belirlemek için yapısal optimizasyon yapılmış, yapısal optimizasyon neticesinde elde edilen optimize parametreler kullanılarak elastik sabitler hesaplanmıştır. Hesaplanan örgü parametresi önceki çalışmalar ile uyum içeresindedir. Ayrıca belirlenen elastik sabitler mekanik kararlılık kriterlerini karşıladığından elastik modül, Vicker sertliği, erime sıcaklığı, Debye sıcaklığı, ses hızları, minimum termal iletkenlik ve anizotropi incelenmiştir. Çalışılan malzemenin Vicker sertliği ve sünek/kırılgan doğası analiz edilmiştir. Ayrıca iç enerji, titreşim enerjisi, entropi ve özgül ısı kapasitesi 0-800 K sıcaklık aralığında değerlendirilmiştir. Hesaplamalarda açık kaynak Quantum Espresso yazılımı ve bu yazılım ile dağıtımı yapılan thermo_pw paketi tercih edilmiştir. Yapılan çalışma ile Ni2VAl bileşiğinin mekanik kararlı, sünek, anizotrop ve yumuşak olduğu görüldü.In this study, the structural, mechanical, and thermodynamic properties of Ni2VAl compound from Heusler family, which has technological importance, were investigated theoretically by first principles method. Firstly, structural optimization was performed to determine the ground state and lowest energy level of the compound, and elastic constants were calculated using the optimized parameters obtained as a result of structural optimization. The calculated lattice parameter agrees with previous studies. In addition, elastic modulus, Vicker hardness, melting temperature, Debye temperature, sound velocities, minimum thermal conductivity and anisotropy were investigated since the determined elastic constants meet the mechanical stability criteria. The Vicker hardness and ductile/brittle nature of the studied material were analyzed. In addition, internal energy, vibrational energy, entropy, and specific heat capacity were evaluated in the temperature range of 0-800 K. In calculations, open-source Quantum Espresso software and thermo_pw package distributed with this software were preferred. With the study, it was seen that the Ni2VAl compound was mechanically stable, ductile, anisotropic, and soft

Generalized 11D supergravity equations from tri-vector deformations

In arXiv:2203.03372 we presented a modification of 11-dimensional supergravity field equations which upon dimensional reduction yields generalized supergravity equations in 10-dimensions. In this paper we provide full technical details of that result which is based on SL(5) exceptional field theory. The equations are obtained by making a non-unimodular tri-vector Yang-Baxter deformation which breaks the initial GL(11) symmetry down to GL(7)xGL(4). We also give some non-trivial solutions to these equations.Comment: v3, refs added, minor correction

Awareness of vocational school students towards environment and nature conservationÖnlisans öğrencilerinin çevre ve doğa korumaya yönelik görüşlerinin değerlendirilmesi

Natural resources which human beings used for fulfilling their basic needs in the past have considerably started to be consumed especially because of the industrial evolution based on fossil fuels and technological developments. Unconscious overconsumption of natural sources has resulted in an increase in environmental problems. These increasing problems and their sensible effects on living creatures have led people to protect the environment and to raise their environmental awareness. Within this scope, in recent years, lessons dealing with environment have started to be given in every phase of the Turkish Educational System from preschool education to university. Within this scope, in recent years, lessons dealing with environment have started to be given in every phase of the Turkish Educational System from preschool education to university. In this study, it is aimed to evaluate the opinions of associate students, who actively study at Ortaca Vocational High School, dealing with the necessity of environment and nature protection and with the scenarios which might happen as a result of the environmental disruption.  In this context, a survey consisting of 21 questions was conducted and the answers of 284 students were analysed by using arithmetic mean(X), percentage, frequency analysis, two independent samples “t” test and  One-way Anova. As a conclusion, it is found that environmental consciousness of the participants increases along with their ages, levels of income and education and it is also found that consciousness of the female participants is higher than the male participants. Özetİnsanoğlunun ilk zamanlar temel gereksinimlerini karşılamak için kullandıkları doğal kaynaklar, özellikle fosil yakıtlara dayalı sanayileşmenin başlaması ve teknolojinin ilerlemesiyle birlikte önemli oranda tüketilmeye başlamıştır. Doğal kaynakların bilinçsizce tüketilmesi, beraberinde çevresel sorunlarının büyümesi sonucunu doğurmuştur. Bu sorunların her geçen yıl artış göstermesi ve canlılar üzerine etkilerinin hissedilir olması, insanların yaşadıkları çevreye sahip çıkmalarına ve çevresel bilinç düzeylerini geliştirmesine neden olmuştur. Bu kapsamda da son yıllarda okul öncesinden yükseköğretime kadar eğitim-öğretim dönemlerinin her aşamasında çevreyle ilgili dersler verilmeye başlanmıştır. Bu çalışmada, Muğla Sıtkı Koçman Üniversitesi Ortaca Meslek Yüksekokulu’nda aktif olarak eğitim alan önlisans öğrencilerinin, çevre ve doğa korumanın gerekliliği ve çevrenin bozulması sonucunda ortaya çıkabilecek senaryolarla ilgili görüşlerinin sosyo-ekonomik göstergelerine göre değerlendirilmesi amaçlanmıştır. Bu bağlamda 21 soruluk anket çalışması yapılmış ve ankete katılan 284 öğrencinin sorulara verdiği cevaplar, aritmetik ortalama (X), yüzde, frekans, bağımsız iki örnek t testi ve tek yönlü varyans analizi (One-way Anova) kullanılarak değerlendirilmiştir. Sonuç olarak katılımcıların yaş, gelir düzeyi ve eğitim düzeyi arttıkça çevresel duyarlılıklarının da arttığı ve kız öğrencilerin çevresel duyarlılıklarının da erkek öğrencilerden daha yüksek olduğu bulunmuştur

Beta, Dipole and Noncommutative Deformations of M-theory Backgrounds with One or More Parameters

We construct new M-theory solutions starting from those that contain 5 U(1) isometries. We do this by reducing along one of the 5-torus directions, then T-dualizing via the action of an O(4,4) matrix and lifting back to 11-dimensions. The particular T-duality transformation is a sequence of O(2,2) transformations embedded in O(4,4), where the action of each O(2,2) gives a Lunin-Maldacena deformation in 10-dimensions. We find general formulas for the metric and 4-form field of single and multiparameter deformed solutions, when the 4-form of the initial 11-dimensional background has at most one leg along the 5-torus. All the deformation terms in the new solutions are given in terms of subdeterminants of a 5x5 matrix, which represents the metric on the 5-torus. We apply these results to several M-theory backgrounds of the type AdS_r x X^{11-r}. By appropriate choices of the T-duality and reduction directions we obtain analogues of beta, dipole and noncommutative deformations. We also provide formulas for backgrounds with only 3 or 4 U(1) isometries and study a case, for which our assumption for the 4-form field is violated.Comment: v2:minor corrections, v3:small improvements, v4:conclusions expanded, to appear in Class. Quant. Gra

A Study For the Evaluation of Alternative Tourism Opportunities in Fethiye Destination

This study has importance in terms of drawing attention to the alternative tourism opportunities of Fethiye destination for tourism; giving idea to public institutions and organizations and tourism operators and entrepreneurs for using Fethiye destinations alternative, existing and potential tourism opportunities more effectively; emphasizing the importance of this potentials contribution to the development of tourism activities in the region; and providing suggestions for the development of alternative tourism opportunities. In this context, existing and potential tourism facilities of Fethiye district were determined by using research methods such as interview, observation and document analysis. Within this scope, information on the current and alternative tourism of the region was gained by mutual interview techniques to be done with the public and private sector institutions, organizations and associations which are effective in decision-making and guiding the organization and implementation of tourism activities, and this data was analyzed by being evaluated scientifically. Alternative tourism potential of Fethiye destination was determined by making use of the data gained as a result of these analyses, and suggestions were offered to ensure a more effective use and involvement of the current alternative tourism potential of the region in tourism activities

Fabrication and Experimental Study of Micro-gripper with Electrothermal Actuation by Stereolithography Method

The aim of the study is to get high displacement values with low actuation voltage from the micro-gripper fabricated by stereolithography (SLA) method. Micro-grippers are devices based on a micro-electro-mechanical system (MEMS) preferred for manipulation and assembly in micro-fabrication. This article presents the modeling, fabrication, and experimental studies of a U-type electrothermal MEMS micro-gripper. The fabrication of the gripper was made by SLA, which is one of the additive manufacturing methods. The arm tip displacement of the gripper has been characterized in real-time by optical microscopy. In electrical characterization studies, the electrical voltage was applied to the pads of the micro-gripper. This voltage value was increased starting from 0V with 1V increments until deterioration was observed in the gripper. The micro-gripper is shown to actuate to a maximum opening displacement of 28.35 mu m at an applied voltage of 5V. The models are employed to examine key factors of the micro-gripper's performance including temperature distribution, displacement, and stresses based on an elastic analysis of structures. Experimental results for the displacement of the micro-gripper's arm tips were found to be in good agreement with the simulation results