It is necessary to choose an appropriate material model to increase the accuracy of prediction of finite element analysis programs. Because every model cannot give good prediction for every material. In this study, the performances of isotropic (von Mises, Tresca) and anisotropic (Hu2003) yield criteria are examined for various materials. The Hu2003 yield criterion is a model that can estimate the materials’ properties with 7 parameters. As a result of the investigation, it is seen that the Hu2003 yield criterion make very successful predictions.

In this study, the effect of dimpled tube which is heated with constant heat flux on heat transfer enhancement is numerically investigated Using physically enhanced tube is one of the passive heat transfer enhancement methods. The reason of using dimpled tube is increase turbulence through the tube and destruct the thermal boundary layer. The numerical study is validated with an experimental study and configurations of cases are expanded with chancing pitch length. The considered cases are conducted in Reynolds number range of 3000 to 8000. Used fluid through the flow and its material copper are selected as water and copper, respectively. The k- e RNG turbulence model is used to simulate turbulent flow adjacent the inner wall surface. The analyses are determined with Nusselt number (Nu), friction factor (f) and performance evaluation criteria (PEC). The highest Nusselt number and the minimum friction factor is obtained when the Reynolds number of 8000, as 135.54 and 0.0422, respectively, for pitch length of 10 mm and 80 mm.

In this study, the design and application of a model developed for the measurement of labor productivity with daily production statistics are presented in the workshops of a medium sized fittings casting. "Foundry and Manufacturing Daily Registration Form" is designed by considering the different products and operators of different and hard work in different workshops in the factory. Design and Development of Models; the products and production processes (processes) of the fittings casting plant were examined and the necessary information for the design of the system was obtained. Therefore; product name, product weight parameters, runner weight, bunch weight, batch product name, number / time parameters have been determined and standardized and an electronic page has been created in Excel environment. It is used in the "Daily Registration Form" design which enables daily production and productive / loss times. The daily record form is in the form of a table and a form on the basis of workshops. From the point of view of ease of use, a study has been developed that is designed in an Excel book environment with the same interface as the daily registration form, and calculates and reports daily and monthly production statistics and productivity rates from the obtained data. Thus, by designing the model reached the conclusion he wanted the factory management; the total mineral amount used for physical efficiency, product weight with runners weights, product quantity, defective products quantity and rates, daily and compared monthly regard to labor productivity and made efficiency observable factors affecting negatively.

With the recent developments in information and communication technologies and the elimination of barriers limiting the movement of capital, the integration between financial markets has gradually increased as financial markets have been reached all over the world at the same time. Developments have deeply affected and linked countries to each other. Thanks to the developments in financial markets and integration, all investors, either individual or institutional, have trouble getting information about the countries they will invest in. At this point, credit rating agencies have emerged in order to eliminate the problem of trust regarding the investors country or business. International credit rating agencies are aiming to minimize the problem of information asymmetry between the financial markets and the surplus and fund deficit parties. International credit rating agencies can be considered as an indicator of the ability of the country to meet the financial liabilities and, in other words, the credit risk of the countries. When evaluated in this respect, it is observed that the countries credit rating grades are effective on the access to international markets, borrowing costs, and potential investor capacity. From this point of dealt with the S&P, Moodys and Fitchs 2002-2018 between the years will be examined using the event study methodology to be BIST 100 also after credit rating descriptions which have been given to Turkey is the impact on selected sectors concerned is located.

This paper intends to present the design scheme of a Proportional Derivative controller for stability and performance of time delay systems in the second order. Inspired from Bode’s ideal system characteristics, phase margin and gain crossover frequency specifications are considered for the system. Then, these specifications are used to obtain the parameters of the controller. The method proposed in the study achieves general computation equations for mentioned systems. Analytically derived formulas by the proposed method are tested with existing plants in the literature and the results are illustrated graphically. It is shown that the tuning method satisfies desired gain crossover frequency and phase margin specifications.

Günümüzde mobil teknolojilerin gelismesiyle birlikte gerek kisiler, kisisel islemlerini gerekse isletmeler, çesitli faaliyetlerini mobil araçlarla gerçeklestirmeye baslamislardir. Mobil cihazlarda konum bilgilerini belirleyerek yer tespiti saglayan konum tabanli uygulamalarin kullaniminin artmasiyla beraber, bu tür uygulamalar kullanici tepkileri açisindan önemli bir konu olmaya baslamistir. Çalismanin amaci, kullanicilarin akilli telefonlarda konum tabanli servisleri kullanim niyetini Birlestirilmis Teknoloji Kabul ve Kullanim Modelini kullanilarak tahmin etmeye çalismaktir. Çalisma kapsaminda nicel arastirma yöntemi ile 280 üniversite ögrencisinin katilimiyla bir anket çalismasi gerçeklestirilmistir. Yapilan anket çalismasinda Janssen’in (2009) kullandigi soru setinden faydalanilmistir. Elde edilen verilerin analizi sonucunda Birlestirilmis Teknoloji Kabul ve Kullanim Model’inin “Performans Beklentisi”, ”Çaba Beklentisi”, “Sosyal Etki” ve “Kolaylastirici Sartlar” olmak üzere 4 boyutu ayri ayri ele alinarak konum tabanli servisleri kullanim niyeti üzerinde etkili oldugu gözlemlenmektedir

In this work, the effects of machining parameters for workpiece and electrode pair in electro discharge machining (EDM) have been experimentally investigated. In the experimental work, copper was used as the electrode, and AISI D2 cold work tool steel was used as the workpiece material. The processing parameters specify three different levels for the discharge current and the pulse duration, respectively. After experiments carried out surface roughness was measured. Material removal rate, tool wear rate and relative wear were calculated. Obtained measurement and calculation results are interpreted using graphs, SEM and microscope images. As a result of the experimental study, it has been determined that the increase of the discharge current and the pulse duration affects the surface roughness and the electrode wear rate negatively and affect the material removal rate positively.

The aim of this study is the leader of learning disability in secondary education physics education. The research was carried out with 235 students who were in the first year of elementary education in the Faculty of Education, Science Education and Computer Education and Instructional Technology Teaching Department. In the study, the necessary questions were taken from the survey named Problems in the Teaching of Physics Subjects in Primary Science Education and solutions prepared by Gül (2006). The analysis of the obtained data was analyzed with SPSS 23.0 for Windows program. At the end of the study, it was found out that the students looked at the prejudiced course of physics, physics was a difficult lesson to understand, the students were less interested in the subjects because of the complexity of the subjects, the labs were not used sufficiently and the experiments about the course were made very little and the learning difficulties were made due to the reasons of being done by the teachers. In addition, learning disabilities in physical education were examined according to some variables (gender, age, type of high school graduated, department you studied). While there was no significant difference between the learning disability in the physical education and gender, age, and the high school type (p <0.05), there was a significant difference with the reading (p> 0.05). Therefore, the problems encountered in the learning of physics courses were tried to be determined and suggestions were made to minimize these problems.

The technological, economic, demographic, cultural and political changes that started in the 1970s led to formal and structural transformations in all countries of the world. These changes also affected the family institution. One of the significant transformations in the family structure is that grandparenting has become a role, including the responsibility of child care. In the contemporary world, the transformation of grandparenting into a role that responds to the need for child care, is due to increased female employment as well as the spread of divorced and single-parent families worldwide since the 1980s. In addition to these developments, the prolonged life span makes the new grandparenting roles, which henceforth include grandchild care responsibility, last longer. However, active participation in the care process is shaped by cultural norms, gender role characteristics and traditional aspects of male and female roles. Therefore, the degree of participation of grandmothers and grandfathers in care activities and their responsibilities for care are different. However, the majority of research on the relationship between grandparents and grandchildren, grandfathers are not focal point. They are included in a very small sample. Data on grandfathers, whose grandparenting experiences are limited in the grandparenting literature, have been reported as findings from grandmothers. In this regard, the aim of this article is to examine the extent to which grandmothers and grandfathers participate in grandchild care needs. The article also aims to reveal the roles that grandmothers and grandfathers undertake in the grandchild care process. Through the interviews with grandparents, it was understood that the grandchildren’s physical care needs were met by their grandmothers and that grandfathers took more responsibility to meet the instrumental needs of their grandchildren.

Adhesive bonding technique is used in many engineering applications. Repairing with fiber composite patches using adhesive bonding technique are widely used for repairing cracks or other defects. Patch application to damaged materials with adhesive bonding is used to extend the service life of the material. In this study, patches were bonded damaged fiber-reinforced laminated composite plates and the dynamic load resistance was investigated numerically. Damaged composite plates and fiber reinforced composite patches are bonded with adhesive. Non-linear finite element analyses were performed in the ABAQUS finite element software. A cohesive zone model based on fracture mechanics was used as the adhesive material model. Low velocity impact behavior of damaged plates repaired by composite patches was also investigated for different patch material such as aluminum and fiber reinforced composite. Impact analyses performed on different impact energy with constant impactor weight were investigated in terms of contact force variations, kinetic energy variations and impact damage. Damaged plates without patch were perforated and damaged. Composite patches absorb impact energy and prevent the perforation.