Dinamik karbotermal indirgeme yöntemi ile TİN ve ZrN tozu üretimi

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Karbotermal İndirgeme ve Nitrürleme (KTİN) tekniği nitrür esaslı teknolojik seramiklerin elde edilmesinde tercih edilen etkili bir toz üretim yöntemdir. Yapılan bu tez çalışmasında KTİN işleminin geliştirilmesi ile yeni bir yaklaşım olan dinamik karbotermal indirgeme ve nitrürleme (DKTİN) yöntemi kullanılarak toz üretimi gerçekleştirilmiştir. Bu yöntemde toz karışımı veya granüller hareketli bir sistem içerisinde sürekli olarak hareket etmektedir. Bu üretim prosesi düşük sıcaklık ve sürelerde oldukça iyi morfolojide ürünler elde etmeye imkan vermektedir. Geliştirilen bu yeni yaklaşım ile nitrür esaslı teknolojik seramikler oldukça kaliteli ve ekonomik bir şekilde üretilebilmektedir. Bu çalışmada, dinamik karbotermal indirgeme ve nitrürleme (DKTİN) yöntemi ile TiN ve ZrN seramik tozlarının üretimi incelenmiştir. Hem TiN hem de ZrN toz üretiminde stokiyometrik oranda oksit tozları ve karbon karası karıştırılarak granüle edilmiştir (C/TiO2=2, C/ZrO2=2). Hazırlanan granüllerden N2 gazı atmosferi altında grafit reaktör içerisinde TiN ve ZrN tozları elde edilmiştir. Yenilikçi bir yaklaşım olan DKTİN işlemi ile reaksiyon sıcaklığı (TiN üretimi için 1350 °C ve 1400 oC, ZrN toz üretimi için ise 1400 °C - 1500 °C), reaksiyon süresi (1-3 saat), reaktörün dönme hızı (2-6 dv/dk), gaz akış debisi (60 ve 120 L/sa) gibi çeşitli test parametrelerinin etkileri araştırılmıştır. Ürünlerin fazları ve mikroyapıları XRD ve SEM analizleri ile karakterize edilmiştir. Yapılan analizler sonucunda 1 saat süre ile 4 dv/dk reaktör dönme hızında ve 60L/sa N2 gazı akışı altında homojen bir şekilde TiN tozu 1400 °C'de, ZrN tozu ise 1500 °C'de oldukça küçük boyutlarda üretilebilmiştir. Bu çalışmada literatürde yüksek sıcaklık ve uzun sürelerde KTİN işlemi ile üretilebilen TiN ve ZrN tozlarının DKTİN ile dahga homajen yapıda ve çok daha ince tane boyutlarında, daha kısa sürelerde ve daha düşük sıcaklıklarda üretilebileceği de kanıtlanmıştır.The Carbothermal Reduction and Nitridation (CRN) method is an effective method for obtaining nitride based technological ceramics. This thesis study was carried out by using dynamic carbothermal reduction and nitridation (DCRN) method. In this method, the powder mixture or granules is moved continuously in a dynamic system. This production process allows to obtain very good quality products in low temperature and time economically. In this study, the production of TiN and ZrN ceramic powders were obtained by dynamic carbothermal reduction-nitridation (DCRN) method. In the production of TiN and ZrN powders, granules were prepared with stoichiometry proportions of oxide powders and carbon black (C/TiO2=2, C/ZrO2=2). TiN and ZrN were obtained from the prepared granules in the graphite reactor under N2 gas flow. By DCRN process which is an innovative approach, the effects of various test parameters such as reaction temperature (1350 °C and 1400 °C for TiN production, 1400 °C-1500 °C for ZrN powder production), reaction time (1-3 hours), rotation speed of the reactor (2-6 rpm), gas flow rate (60L/h) was investigated. The phases and microstructures of the samples were characterized by XRD and SEM analyzes. As a result of these analyzes, at a reactor rotation speed of 4 rpm in 1 hour under N2-gas flow rate of 60 L/h, powders of micron in size and homogeneously form were produced at 1400 °C and 1500 °C for TiN and ZrN phase, respectively. In this study, it is proved that TiN and ZrN powders produced by CRN process in high temperature and long time can be produced using DCRN process much less time and lower temperatures with fine size and more in homogeneity form

Geophysikalische Erfassung von Feuchte- und Substratheterogenitäten im Boden auf unterschiedlichen Skalen

Soils interact with the hydro-, bio- and atmosphere and fulfil different environmental functions. Sufficient analysis of current and historical processes in soils is necessary to optimise soil conservation and to minimize damage to the ecosystem. Modelling of transport processes in soils provides knowledge of the complex environmental interaction. This requires extensive data with an appropriate resolution. The general aim of this thesis was to use geophysical methods for determining spatial and temporal heterogeneity of water and substrate. DC-geoelectrics and GPR provide three-dimensional images of near surface structures based on changes in electromagnetic and electrical conductivity. It is shown that geophysical methods enable spatial mapping of soil properties on different scales and that these methods can be used at different scales. This is important for a variety of reasons in disciplines such as soil sciences, hydrology and agronomy

Musculoskeletal Pain, Related Factors, and Posture Profiles Among Adolescents: A Cross-Sectional Study From Turkey

Purpose: The aim of the study was to evaluate musculoskeletal pain due to mechanical reasons and related risk factors in adolescents and to define posture profiles of adolescents. Design: A cross-sectional study. Methods: The study was conducted with 2221 adolescents between February 2015 and May 2015. The questionnaire used to collect data consisted of three parts: (1) descriptive characteristics of the participants, (2) pain assessment of 14 parts of the body, and (3) Back Pain and Body Posture Evaluation Instrument (BackPEI). Results: The prevalence of low back pain among the participants was 73.3% (n = 1,343), while the prevalence of back pain was 68.4% (n = 1,254). The participants attributed their pain to their poor sitting postures at school (38.1%, n = 847) and carrying school backpacks (84.1%, n = 1,713). There was a statistically significant difference in the physical activities of adolescents and the BackPEI score (z = 4.40; p = .001). Posture factors of the BackPEI score increased while school desk comfort score increased (Spearman's rho = 0.148; p = .001), but it decreased while the school grades of the adolescents increased (Spearman's rho [ρ] = −0.161; p = .001). Conclusions: According to this study, body posture was related to musculoskeletal pain and was correlated with physical activities, school desk comfort, and school grades of the adolescents. It is suggested that correct posture and ergonomic positions should be taught to adolescents when using computers, carrying school backpacks, and sitting in school chairs to prevent musculoskeletal pain. © 2020 American Society for Pain Management Nursin

Application of experimental design on determination of aluminum content in saline samples by adsorptive cathodic stripping voltammetry

Adsorptive cathodic stripping voltammetric determination of aluminum at ng mL-1 levels in salt samples based on the metal complexation with Calcon (1-(2-hydroxynaphthylazo)-2 naphthol-4-sulfonic acid) and the subsequent adsorptive deposition onto a hanging mercury drop electrode was studied. Central composite design was used as a design method. Several chemical and instrumental parameters (pH, ligand concentration, deposition time, deposition potential, and complexing time) were involved in the experimental design. Analytical parameters such as repeatability, linearity, and accuracy were also investigated and the detection limit was found as 0.32 ng mL-1.Ege University research fund (Project no: 2004 Fen 071

PRIDA: PRIvacy-preserving Data Aggregation with multiple data customers

We propose a solution for user privacy-oriented privacy-preserving data aggregation with multiple data customers. Most existing state-of-the-art approaches present too much importance on performance efficiency and seem to ignore privacy properties except for input privacy. Most solutions for data aggregation do not generally discuss the users’ birthright, namely their privacy for their own data control and anonymity when they search for something on the browser or volunteer to participate in a survey. Still, they are ambitious to secure data customers’ rights (which should come later). They focus on resulting in an efficiency-oriented data aggregation enabling input privacy only. We aim to give importance to user privacy, and we have designed a solution for data aggregation in which we keep efficiency in balance. We show that PRIDA provides a good level of computational and communication complexities and is even better in timing evaluation than existing studies published recently (i.e., Bonawitz et al. (CCS’17), Corrigan-Gibbs et al. (NSDI’17), Bell et al. (CCS’20), Addanki et al. (SCN’22)). We employ threshold homomorphic encryption and secure two-party computation to ensure privacy properties. We balance the trade-off between a proper design for users and the desired privacy and efficiency

Multidimensional Linear Cryptanalysis of Feistel Ciphers

This paper presents new generic attacks on Feistel ciphers that incorporate the key addition at the input of the non-invertible round function only. This feature leads to a specific vulnerability that can be exploited using multidimensional linear cryptanalysis. More specifically, our approach involves using key-independent linear trails so that the distribution of a combination of the plaintext and ciphertext can be computed. This makes it possible to use the likelihood-ratio test as opposed to the χ2 test. We provide theoretical estimates of the cost of our generic attacks and verify these experimentally by applying the attacks to CAST-128 and LOKI91. The theoretical and experimental findings demonstrate that the proposed attacks lead to significant reductions in data-complexity in several interesting cases

Retrospective Analysis of Skull and Spine Traumas

Objective:In this study, in patients who applied to the forensic medicine outpatient clinic due to skull and spine trauma; We aimed to compare categorical data by defining age, gender, causes of trauma, trauma site, fracture type and accompanying pathologies.Methods:Files and computed tomography reports of a total of 105 patients, 24 women and 81 men, between the ages of 18 and 75, who were exposed to skull and spine trauma, registered in the database of the Hitit University Erol Olçok Training and Research Hospital Forensic Medicine Polyclinic Unit between 01.01.2017 and 31.12.2020 examined. In cases; gender, age, cause of trauma, fracture type, injury site, multiple site injuries and presence of pathologies accompanying trauma were evaluated. Data analysis was performed with the IBM SPSS Statistics 22.0 statistical program. Categorical data were compared with chi-square and Fisher Exact tests.Results:The most trauma was detected in male individuals aged 51-60 years. The most common cause of trauma was traffic accidents with a rate of 48.6% (51 cases). In the skull, frontal linear fractures and in the spine, lumbar vertebrae corpus fractures were the most common lesions. Pneumocephaly, spinal injuries and paraplegia were seen as a complication.Conclusion:We think that our study will be beneficial in terms of guiding physicians in the observation, diagnosis and reporting processes of patients who apply to the Forensic Medicine units of hospitals

Effectiveness of tranexamic acid on bleeding in conization

Objective: Bleeding is the most common complication of conization of cervix. Hemostatic sutures, intraoperative ferric subsulfate, or vasopressin can be used when intraoperative bleeding occurred, whereas oral tranexamic acid (TA) may be used for post-operative bleeding. In this study, we aimed to find out whether intraoperative cervical TA administration in patients undergoing conization caused changes in the amount of intraoperative bleeding and post-operative hemogram. Material and Methods: Patients who have undergone cervical conization between January 2019 and July 2019 in Zeynep Kamil Health Application and Research Center Gynecological Diseases and Birth Clinic were evaluated. One hundred and five patients were included to our study. One ampoule of 10% TA was applied cervically to 47 of these patients. Both groups were evaluated in terms of measuring the intraoperative amount of blood in the aspirator, changes in post-operative hb/htc/plt values compared to the pre-operative values, and the rate of post-operative bleeding. Results: In our study, the amount of intraoperative hemorrhage and pre-operative hemoglobin, hematocrit, and platelet values compared to the post-operative values were found to be similar in both groups. Conclusion: Although TA has been shown to be effective on hemorrhage in benign gynecologic operations, menorrhagia, and postpartum hemorrhages, no significant effect on hemorrhage in conization with cervical TA administration has been demonstrated

Oxidant/antioxidant potentials and heavy metal levels of Pisolithus arhizus and its effects on cardiovascular diseases

600-604Pisolithus arhizus (Scop) Rauschert is a cosmopolitan mushroom in warm temperate regions of the world and forms ectomycorrhizas associations with a wide range of tree species (both angiosperms and gymnosperms). P. arhizus samples were collected from a pine forest in Antalya province (Turkey). Powdered mushroom samples were extracted with ethanol (EtOH) using a Soxhlet apparatus at 50 °C, then concentrated under pressure at 40 °C in a rotary evaporator, and stored at 4 °C in airtight containers. Rel Assay Kits were used to determine the total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) of mushroom extracts. The elemental contents of the mushrooms were then determined using the atomic absorption spectrophotometer. It was determined that the heavy metal content in P. arhizus were found to be generally at optimal levels and the TOS value of mushroom was exceptional. Heavy metals are toxic, they may have chronic degenerative changes on organs. Vascular effects of heavy metals may contribute to a variety of pathologic conditions. Heavy metals resulting in pathophysiological changes causes atherogenic events like increased oxidative stress, inflammatory response, and coagulation activity. It has been determined that P. arhizus may be an important source of antioxidants