Ownership structure in BIST - Capital structure relation Granger causality test a comparative application between BIST industrial index and service index

Abstract. In this study, it was aimed to determine whether there is a bidirectional relationship between the ownership and capital structures through the variables representing the ownership and capital structures of 142 businesses, which are included in the Service and Industrial Indexes of Borsa Istanbul (BIST) between the years of 2006-2014. The capital structure in the research is represented by the leverage ratio (TBTV), which determines the extent to which a business is dependent on debt and to determine how much of the assets owned by the business are financed with debt, while the ownership structure is represented by the largest shareholder’s equity (EBOP), the foreign share (YAP), the corporate investor ratio (KURY) and the number of the shareholders with more than 10% share of the business (ORTAK). The factors influencing the bi-directional causality between the ownership and the capital structures were researched with the Panel Vector Autoregressive Model (VAR). In the scope of the VAR analysis, Granger causality test and the impulse response analyzes were also performed. It was found in the result of the analysis that in the model where the capital structure (TBTV) is a dependent variable in the service index, none of the independent variables belonging to the ownership structure has a causality relation through the TBTV. In the model where the variables belonging to the ownership structure were dependent variables, it was found that the independent variable belonging to the capital structure (TBTV) is the reason of the change in the ownership variables of EBOP, HAO and KURY variables. According to the results obtained, 1 period delay in the capital structure causes decrease in EBOP and HAO; increase in KURY. As to the businesses in the industrial index, a causality relationship was not seen between the ownership structures and the capital structures in the context of these variables and the two structures do not effect each other.Keywords. Ownership structure, Capital structure, Granger casuality, BIST. JEL. C33,G10, G32

Investigation of the Effects of Heat Treatment Conditions on Phase Change, Hardness and Corrosion Behavior in the 1.4462 (AISI 2205) Duplex Stainless Steel

Paslanmaz çelikler günümüzde son derece önemli bir yapı malzemesidir. İçerdiği çift faz ile dubleks paslanmaz çelikler son yıllarda oldukça öne çıkan bir malzeme türü olmuştur. 1.4462 paslanmaz çelikleri üstün korozyon ve mekanik özellikler göstermesine rağmen yüksek sıcaklık uygulamalarında mikroyapıdaki faz dönüşümleri kullanım alanlarını sınırlamaktadır. Bu çalışmada, 1.4462 dubleks paslanmaz çeliğine yüksek sıcaklık ısıl işlemi uygulanarak mikroyapıdaki faz dönüşümlerinin sertlik ve korozyon özellikleri üzerine etkileri incelenmiştir. Bu amaçla ısıl işlem uygulanmış numunelere optik mikroskop (OM), taramalı elektron mikroskobu (SEM), enerji dağılımlı X- ışını spektroskopisi (EDS), sertlik ve elektrokimyasal korozyon deneyleri yapılmıştır. Elde edilen sonuçlara göre yüksek sıcaklıklarda oluşan ikincil fazların malzemenin mekanik ve korozyon özelliklerini etkilediği tespit edilmiştir.Stainless steels are significant building material today. With the double phase, it contains, duplex stainless steels (DSS) have become a very prominent material type in recent years. Although 1.4462 stainless steels show superior corrosion and mechanical properties, their usage areas are limited in high-temperature applications due to phase transformations in the microstructure. In this study, by applying high-temperature heat treatment to 1.4462 duplex stainless steel, the effects of phase transformations in the microstructure on hardness and corrosion properties were investigated. For this purpose, optical microscope (OM), scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDS), hardness and electrochemical corrosion tests were performed on heat-treated samples. According to the results, it was determined that secondary phases formed at high temperatures affect the mechanical and corrosion properties of the material

A Review on Additıve Manufacturing Technologies

Eklemeli üretim, bir 3B CAD modelinin, malzemenin tabakalar halinde birleştirilerek fiziksel bir parçaya dönüştürüldüğü üretim işlemidir. Eklemeli üretim son yıllarda oldukça önem kazanmış ve gelecekte daha çok hayatımızda rol alması beklenen son derece önemli bir teknolojidir. Eklemeli üretim, günümüzde otomotiv, havacılık, uzay, sağlık-inşaat sektörleri, enerji gibi alanlarda devrim yaratmış bir yöntemdir. Dolayısıyla, eklemeli üretim teknolojisini anlayabilmek günümüz için oldukça stratejik bir konudur. Bu çalışmada, eklemeli üretime ait genel bilgi verilmiş ve günümüzde en fazla ticari olarak kullanılan eklemeli üretim yöntemleri anlatılmıştır. Çalışmada ayrıca, eklemeli üretimin kullanım alanlarından bahsedilerek, gelecekteki potansiyeli değerlendirilmiştir.Additive manufacturing is a manufacturing process in which a 3D CAD model is combined into the layer by layer and converted into a physical part. Additive manufacturing has gained considerable importance in recent years and is an extremely important technology that will play a role in our lives in the future. Additive manufacturing is a revolutionary method in the automotive, aerospace, health and construction sectors, energy and more. Therefore, understanding of additive manufacturing technology is a very strategic issue for today. In this study, general information about additive manufacturing is given and the most commercially used additive manufacturing methods are explained. Then, the usage areas of additive manufacturing are mentioned and its future potential is evaluated

Genome mapping in F1 population of crossbred Italia and Mercan grape varieties: Establishment of AFLP and SSR linkage groups towards significant morphological characters and fungal diseases

This research aims at the establishment of a genome map for F1 population developed by crossbreeding of Italia and Mercan grape varieties. A co-dominant marker SSR (Simple Sequence Repeats) and a dominant marker AFLP (Amplified Fragment Length Polymorphism) were used in the study. Double-pseudotestcross mapping technique was used for genome mapping. The study analyzed 60 plants selected from the F1 population as well as the parental grape varieties, which differed in regards to resistance to diseases and some morphological characteristics. Amplification products were evaluated as “available” and “not available” at the end of silver staining for SSR and radioactive marking for AFLP. Polymorphic loci were determined according to their segregation ratios ranging between 1: 1 and 3: 1 at the end of X2 tests. 3.0 LOD value was used in Mapmaker/Exp 3.0 package program for mapping. Two separate genetic linkage maps (maternal and paternal) were observed which included 6 and 1 linkage groups, respectively. Linkage of the loci located on the linkage groups to the observed diseases and morphological characters were analyzed with regression and variance analyses. A total of 818 primer pairs were tested on the two parents (Italia and Mercan), 60 F1 (Italia × Mercan population) and two reference grape cultivar (Cabarnet Sauvignon and Merlot), successfully amplifying 112 markers. When the resistance traits to fungal diseases were analyzed during the study, no markers related with resistance to Botrytis cinerea and downy mildew could be found. However, it was found that the markers (VrZAG29a, VrZAG29c) related with the control of resistance to powdery mildew were on a locus which was in linkage group.Keywords: Vitis vinifera L., grape, SSR, AFLP, mappingAfrican Journal of Biotechnology Vol. 9(36), pp. 5879-5886, 6 September, 201

Effect of Waste Titanium Chips Addition Into the Aluminum Alloys on Their Microstructure

In the present study, turning chips were preferred to add titanium into liquid aluminum. Although being easy to reach and cheap, the chips were thought to be effective in minor titanium addition with their large surface area. Experimental studies have been carried out with A356 casting alloy and commercial purity aluminum. The effects of different process parameters were investigated on titanium transfer efficiency, microstructural and microhardness properties of the formed phases. The processes were carried out between 740 - 820 °C, for 2, 4, and 6 h, with the amount of added chips 5 and 10 wt.% (3 and 6 vol.%). The experiments were conducted with both commercially pure Al and A356 alloy. The microstructural investigations and microhardness measurements were carried out on the formed Al3Ti and (Al, Si)3Ti phases. The first noticeable result was that titanium transfer was more efficient in pure aluminum than in the A356 alloy. Also, it was observed that this difference became more significant with an increase in wt.% addition. The measured microhardness values were also differentiated depending on the Si content of the formed Al3Ti compound. Due to the presence of high Si content in A356 alloy, transference efficiencies of Ti were found highly limited compared to pure aluminum as the silicon enrichment in the Al3Ti compound reduces the diffusion of titanium and the growth rate of Al3Ti particles. Maximum transference efficiency was found 47.05% with 10 %wt. chip addition in commercially pure aluminum at the processing conditions of 780 °C for 4 h

Measurement of the effects of capital structure in enterprises on the probability of bankruptcy: A research on the enterprises traded in the BIST industrial index

Abstract. This study aims to measure the relationship between the Altman Z-Score, which is used to determine the financial failure of the enterprises, and the decisions on the capital structure. In other words, it has been tried to determine whether the capital structure has any effect on the risk of bankruptcy. In the scope of the research, 112 enterprises that continue their activities uninterruptedly and are traded on the industrial index between 2006 and 2014 have been examined. Panel data analysis has been utilized in order to examine the effect of capital structure on the financial failure and/or performance in the enterprises. Through the use of the Altman Z-Score (ZSCORE) which is an indicator of the risk of bankruptcy in the models formed based on the panel data analysis, a statistically negative and significant correlation has been found between the capital structure of the enterprises and the risk of bankruptcy. The leverage ratio (TBTV), which is considered as a variable that represents the capital structure, and thenon-debt tax shields (BDVK), which represent the control variable, have been used. In the correlation between the control variable and the ZSCORE, it has been found that the BDVK has not any significant effect on the ZSCORE and has not caused any increase in the total variance. The findings of this study indicate that the debt ratio in the enterprises causes an increase in financial failure, and they are also compatible with the validity of the trade-off theory.Keywords. Capital structure, Altman Z Score, Panel Data, Financial Performance, Trade-Off Theory, BIST.JEL. C23, G32, G33

Effects of Hot Isostatic Pressing and Heat Treatments on Structural and Corrosion Properties of Direct Metal Laser Sintered Parts

Purpose – This paper aims to investigate the effects of various heat treatments on microstructure, hardness, porosity and corrosion properties of the parts. Design/methodology/approach – Hot isostatic pressing (HIP) process, various heat treatments and their combinations were applied to the AlSi10Mg parts produced by direct laser metal sintering (DMLS). Findings – It has been found that the HIP process, which is a post-processing process, reduces the amount of porosity in DMLS-AlSi10Mg material, thus improves corrosion resistance significantly. Originality/value – In this study, the HIP process and subsequent T6 heat treatments were applied to AlSi10Mg parts produced by the DMLS technique. The study aims to increase the corrosion resistance of AlSi10Mg parts by reducing porosity with the HIP process and by altering the microstructure with the T6 process

Yönetim Kurulu Yapısının Yatırım Etkinliği ve Firma Değeri Üzerindeki Moderatör Etkisi: BİST Örneği / The Moderating Effect of Board Structure on Investment Efficiency and Firm Value: BIST Example

Bu araştırmada, yönetim kurulu büyüklüğü ve yönetim kurulu bağımsızlığının yatırım etkinliği ve firma değeri arasındaki ilişki üzerindeki ılımlaştırıcı etkileri incelenmiştir. Örneklem, 2012-2021 yılları arasında Borsa İstanbul'da (BİST) işlem gören 269 finans sektörü dışındaki firmadan oluşmaktadır. Firma değeri Tobin Q oranı kullanılarak ölçülmüştür. Sonuçlar, yatırım etkinliği ile firma değeri arasında pozitif bir ilişki olduğunu ortaya koymuştur. Ayrıca, yönetim kurulu büyüklüğünün yatırım etkinliği ve firma değeri arasındaki ilişki üzerinde pozitif ve anlamlı bir ılımlaştırıcı etkiye sahip olduğu bulunmuştur. Buna göre yönetim kurulu büyüklüğü arttıkça yatırım etkinliğinin firma değeri üzerindeki etkisi de artmaktadır. Ancak, yönetim kurulu bağımsızlığı bu ilişki üzerinde anlamlı bir ılımlaştırıcı etki göstermemiştir. Bu bulgular, yönetim kurulu yapısının yatırım etkinliğinin firma değeri üzerindeki etkisini nasıl etkilediğinin anlaşılmasına katkıda sağlamakta ve böylelikle kurumsal finans literatürüne katkıda bulunmaktadır

Analytical Formulation for Diesel Engine Fueled with Fusel Oil/Diesel Blends

The experiments related to reduction of gases from the exhaust emissions of internal combustion engines, usually conducted in laboratory conditions, are quite laborious and costly. For these purposes, modelling engine experiments with algorithms have emerged as a way forward. In this paper, the operation of diesel engine is modelled through experimental dataset, which has input variables such as engine load, fuel type and output variables such as carbon monoxide (CO), carbon dioxide (CO2), oxides of nitrogen (NOx), hydrocarbon (HC), smoke, Brake Specific Energy Consumption (BSEC) and maximum in-cylinder pressure (Cpmax). Artificial intelligence based Symbolic Regression (SR) algorithms have been used to derive analytical equations of each output variable. The derived equations and experimental results are plotted on the same graph to show the accuracy of the obtained equations. The coefficient of determination (R2) is between 0.98 and 0.99 in all equations. In addition, Mean Error Percentage (MEP) value is less than 10 in all equations. The performance of SR algorithms is compared with Artificial Neural Network (ANN), Support Vector Machines (SVM), instance-based and K nearest based classifier (IBk), ensemble method-based bagging algorithm, and decision tree-based REPTree algorithms. SR algorithms exhibit the best performance for all output variables. IBk algorithm exhibits the second-best performance for the BSEC, CO, CO2, HC and NOx output variable. SVM algorithm exhibits the second-best performance for the Cpmax output variable and Bagging algorithms exhibits the second-best performance for the smoke output variable. The operation of diesel engine can be predicted using these equations and algorithms for further research

Myocardial injury in COVID-19 patients is associated with the thickness of epicardial adipose tissue

Aim High sensitive troponin (hs-TnI) levels may increase secondary to Coronavirus disease-2019 (COVID-19), and this increase is associated with cardiovascular mortality in COVID-19 patients. Epicardial adipose tissue (EAT) is associated with myocardial injury directly as a reservoir tissue for coronavirus, and indirectly through mediators it secretes as an apocrine gland. We aimed to evaluate the relationship between myocardial injury secondary to COVID-19 infection and EAT thickness. Material and methods Thoracic computed tomography (CT) was performed in 73 consecutive patients diagnosed with COVID-19. EAT thickness and volume were calculated by two radiologists blind to the study data. We formed two groups according to hs-TnI concentrations, patients with myocardial damage (hs-TnI >= 11.6 ng/l) and without myocardial damage (hs-TnI<11.6 ng/dl). Results A total of 46 patients were women (63.0%). The mean age was 66.4 +/- 12.3 yrs in the myocardial injury group and 55.9 +/- 9.7 yrs in the group without myocardial injury (p<0.001). There were 20 hypertensive patients (68.9%) in the injury group, while there were 12 hypertensive patients (27.3%) in the group without injury (p=0.001). Glucose, C-reactive protein, D-dimer, white blood cell count, neutrophil, and neutrophil/lymphocyte ratio were higher in the injury group (p<0.05, for all variables). The mean EAT thickness was 5.6 +/- 1.6 mm in the injury group, whereas it was 4.8 +/- 1.8 mm in the group without injury (p=0.031). EAT thickness of 4.85 mm and above was associated with the myocardial injury with 65% sensitivity and 39% specificity (AUC=0.65, 95% CI: 0.52-078, p=0.031). Conclusion In patients with COVID-19 infection, higher rates of myocardial injury were observed as the EAT thickness increased. Epicardial adipose tissue, contributes to cytokine-mediated myocardial injury either directly or indirectly by acting as a reservoir for coronavirus. Increased EAT thickness is associated with myocardial injury in COVID-19 patients