Investigation of adhesion and tribological behavior of borided aısı 310 stainless steel

In the present study, the effects of the boriding process on adhesion and tribological properties of AISI 310 steel were investigated. Boriding was performed in a solid medium consisting of Ekabor-II powders at 1123 and 1323K for 2 and 6 h. The boride layer was characterized by optical microscopy, the X-ray diffraction technique and the micro-Vickers hardness tester. The X-ray diffraction analysis of the boride layers on the surface of the steels revealed the existence of FexBy, CrxBy and NixBy compounds. Depending on the chemical composition of substrates, the boride layer thickness on the surface of the AISI 310 steel was found to be 56.74 μm. The hardness of the boride compounds formed on the surface of the AISI 310 steel ranged from 1658 to 2284 HV0,1, whereas the Vickers hardness value of the untreated steel AISI 310 was 276 HV0,1. The wear tests were carried out in a ball-disc arrangement under a dry friction condition at room temperature with an applied load of 10N and with a sliding speed of 0.3 m/s, at a sliding distance of 1000m. The wear surfaces of the steel were analyzed using an SEM microscopy and X-ray energy dispersive spectroscopy EDS. It was observed that the wear rate of unborided and borided AISI 310 steel ranged from 4.57 to 71.42 mm3/Nm

Investigation of wear behavior of borided dın x15crnisi25 steel

In the present study, effect of the boriding process on adhesion and tribological properties of DIN X15CrNiSi25 steel has been investigated. Boriding was performed in a solid medium consisting of Ekabor- II powders at 1123 and 1323K for 2 and 6 h. The boride layer was characterized by optical microscopy, Xray diffraction technique and the micro-Vickers hardness tester. . X-ray diffraction analysis of boride layers on the surface of the steels revealed the existence of FexBy, CrxBy and NixBy compounds. Depending on the chemical composition of substrates, the boride layer thickness on the surface of the X15CrNiSi25 steel was found to be 56.74 μm. The hardness of the boride compounds formed on the surface of the X15CrNiSi25 steel ranged from 1658 to 2284 HV0,1, whereas Vickers hardness values of the untreated steel X15CrNiSi25 were 276 HV0,1. The wear tests were carried out in a ball-disc arrangement under a dry friction condition at room temperature with an applied load of 10N and with a sliding speed of 0.3 m/sec at a sliding distance of 1000m. The wear surfaces of the steel were analyzed using a SEM microscopy and X-ray energy dispersive spectroscopy EDS. It was observed that the wear rate of unborided and borided X15CrNiSi25 steel ranged from 4.57 to 71.42 mm3/Nm

Investigation of diffusion kinetics of borided x6cr17 steel

In this study, the case properties and diffusion kinetics of DIN X6Cr17 steel borided in Ekabor-II powder were investigated by conducting a series of experiments at temperatures of 1123, 1223 and 1323K for 2, 4 and 6 h. The boride layer was characterized by optical microscopy, X-ray diffraction technique and micro-Vickers hardness tester. X-ray diffraction analysis of boride layers on the surface of the steels revealed the existence of FexBy, CrxBy and NixBy compounds. The thickness of boride layer increases by increasing boriding time and temperature for all steels. Depending on the chemical composition of substrates, the boride layer thickness on the surface of the X6Cr17 steel was found to be 50.48 μm and 91.62 μm, respectively. The hardness of the boride compounds formed on the surface of the X6Cr17 steel ranged from 1658 to 2284 HV0,1

Environment, education, and economy nexus: evidence from selected EU countries

Among the most fundamental problems today are environmental problems. As people earn higher incomes as a result of getting a good education, their sensitivity to environmental problems increases. As the income level of both the consumers who have received quality education and the producers who make conscious production increases, their demand for environmental quality and their sensitivity to environmental problems will also increase so it is thought that educational expenditures and policies can affect the number and cost of environmental problems. On the other hand, economic activities comprehensively consume natural resources and impact the ecological quality adversely. Therefore, GDP and the educational expenditures variables are used in the model. The aim of this study is to analyze the relationship between environment, education, and economy during the period of 1998-2017 from selected EU countries (Austria, Italy, the Netherlands, Norway, Poland, Portugal, Romania, and Slovakia). As a result of the panel data analysis, according to the Durbin-Hausman cointegration test result, a long-run relationship between the variables was determined at the level of 1%. According to the results of the Dumitrescu-Hurlin causality test, a unidirectional causality relationship from educational expenditures to ecological footprint at the level of 5%, a unidirectional causality relationship from ecological footprint to renewable energy at the level of 1%, and a bidirectional causality relationship at the level of 1% between ecological footprint and GDP were determined. According to the results of Granger causality test based on the VEC model, a unidirectional causality relationship from ecological footprint to educational expenditures at the level of 5%, and bidirectional causality relationship between ecological footprint and renewable energy (from ecological footprint to renewable energy at the level of 10%; from renewable energy to ecological footprint at the level of 1%) were determined. Based on the findings, it can be concluded that economic and educational policy makers should be aware that they have important consequences on environment

Gestational trophoblastic neoplasia after miscarriage with dilatation and curettage with normal histological findings

Gestational trophoblastic neoplasia may develop after a molar, term, ectopic pregnancy, or an abortion. The diagnosis of gestational trophoblastic neoplasia can be made solely based on changes in human chorionic gonadotropin levels without pathologic confirmation. It is important to distinguish molar pregnancy from that disease, as treatment for these entities differs. However, gestational trophoblastic neoplasia developing after a term or ectopic pregnancy, or an abortion may be difficult to diagnose, because there is no tissue confirmation. In such cases, the time between a previous pregnancy event and the current event, and an inconsistency between very high levels of human chorionic gonadotropin and the size of lesions in the uterine cavity may be warning signs of gestational trophoblastic neoplasia. The role of curettage in the treatment of the disease is limited. We present a case of gestational trophoblastic neoplasia that developed after an abortion, serving as a reminder illustration that gestational trophoblastic neoplasia can develop not only after molar pregnancies, but also after other pregnancy events

A tumoral mass (local recurrence of renal cell carcinoma) causing massive intraabdominal bleeding after blunt abdominal trauma

AbstractBackgroundSolid organ injury after abdominal trauma is a common condition, however, injury of the local recurrent tumoral masses following abdominal trauma is rare. The injuries and bleeding in recurrent tumors tend to be highly serious since they are more fragile. The bleedings caused by renal cell carcinomas and by the traumatic laceration of their recurrence commonly occur in the retroperitoneum.In this report, we present a 55-year-old female patient who underwent emergency surgery due to intraabdominal bleeding and bleeding was from the recurrence of a renal cell carcinomas.Presentation of caseThe 55-year-old female patient was admitted to the emergency service with intraabdominal bleeding. Physical examination revealed tenderness in the right lower quadrant, particularly in the traumatic area. Ultrasonography and computed tomography revealed diffuse intraabdominal fluid and a ruptured bleeding mass was excised. Pathological analysis indicated that the mass was isolated local recurrence of renal cell carcinoma.DiscussionSolid organ injury caused by blunt abdominal trauma may be accompanied by tumoral laceration; however, minor bleeding may occur in cases with blunt trauma, coexistence of blunt abdominal trauma with local recurrence and massive bleeding is extremely rare.Control of bleeding is more challenging in tumoral tissues compared to normal tissues. The bleeding intraabdominal area rather than the retroperitoneal area, and this condition was attributed to the peritoneal tear caused by the trauma.ConclusionLocal recurrent tumoral masses may be the source of the intraabdominal massive bleeding after blunt trauma

Ergenlerde Okul Tükenmişliği ve Okul Bağlılığı: Facebook Bağımlılığının Aracı ve Farklılaştırıcı Rolü

In this study, the mediating and moderating role of Facebook addiction in the relationship between school burnout, and school engagement was investigated. The study group comprised of 283 students continuing to 6th, 7th, 8th and 9th grades. The data were collected by School Burnout Inventory, School Engagement Scale and Facebook Addiction Scale. As a result of the correlation analysis, a significant positive correlation was found between school burnout and Facebook addiction. Also, school engagement was negatively related to school burnout and Facebook addiction. The structural equation model findings indicated that Facebook addiction had a partial mediating role between school burnout and school engagement. The results of the bootstrap analysis supported the significance of the partial mediating role. Besides, as a result of the regression analysis, it was found that Facebook addiction had a differentiating role in the relationship between burnout and school engagement. Research findings are discussed in light of the literature. It is recommended to carry out studies to prevent social media addiction and to enhance conscious technology use. These studies are considered to contribute to reduce school burnout of the students and increase their school engagement.Bu çalışmada Facebook bağımlılığının okul tükenmişliği ve okul bağlılığı arasındaki ilişkide aracı ve farklılaştırıcı rolü araştırılmıştır. Çalışmanın katılımcıları 6., 7., 8. ve 9. sınıfta öğrenim gören 283 öğrenciden oluşmaktadır. Veriler Okul Tükenmişliği Ölçeği, Facebook Bağımlılığı Ölçeği ve Okul Bağlılığı Ölçeği aracılığıyla toplanmıştır. Korelasyon analizi sonucunda okul tükenmişliği ve Facebook bağımlılığı arasında anlamlı düzeyde pozitif ilişki bulunmuştur. Okul bağlılığı ise okul tükenmişliği ve Facebook bağımlılığı ile anlamlı düzeyde negatif ilişkilidir. Yapısal Eşitlik Modeli sonuçları okul tükenmişliği ve okul bağlılığı arasındaki ilişkide Facebook bağımlılığının kısmi aracı rolü olduğunu göstermektedir. Bootstrap analizi sonuçları kısmi aracı rolün anlamlılığını desteklemektedir. Ayrıca regresyon analizi sonucunda okul tükenmişliği ve okul bağlılığı arasındaki ilişkide Facebook bağımlılığının farklılaştırıcı rolü olduğu bulunmuştur. Sonuçlar alanyazın eşliğinde tartışılmıştır. Sosyal medya bağımlılığı önlemeye ve teknolojinin bilinçli kullanımını geliştirmeye yönelik çalışmaların yapılması önerilmektedir. Bu çalışmaların öğrencilerin okul tükenmişliğinin azalmasına ve okula olan bağlılıklarının artmasına katkısı olabileceği düşünülmektedir

The Effect of the COVID-19 Pandemic Process on the Incidence of Intestinal Parasites; Aydın Province Example

Objective:The Coronavirus disease-2019 (COVID-19) pandemic, which started in our country in March 2020, has caused a sudden and dramatic change in our habits. As a result of the pandemic measures directly effective in the transmission of parasites, it has become important to investigate the possible effect of the COVID-19 pandemic process on the incidence of intestinal parasites.Methods:In order to examine the situation before and after the pandemic, all stool and cellophane tape test results examined from March 11, 2018 to March 11, 2022 in Aydın Adnan Menderes University Faculty of Medicine Parasitology Laboratory were evaluated retrospectively. The relationship between the socio-demographic characteristics of the cases, the distribution of the months and years of diagnosis and the prevalence of parasites were also evaluated.Results:Of the 13,036 stool samples examined, 67.42% belong to the pre-pandemic and 32.58% belong to the post-pandemic period. In total, 1.959 stool samples were positive for at least one parasite, of which 71.41% were from the pre-pandemic. Blastocystis spp. was the most frequently detected parasite both before (14.63%) and after the pandemic (12.59%). Of the 3.194 cellophane tape examined, 72.32% belonged to the pre-pandemic and 27.68% post-pandemic period, and Enterobius vermicularis eggs were detected in 246 (7.70%) of all. The majority of E. vermicularis positive samples (82.11%) were belonged to the pre-pandemic period. The number and positivity rates of stool and cellophane tape samples examined in the post-pandemic period showed a significant decrease (p<0.05).Conclusion:It was observed that the incidence of intestinal parasites decreased significantly during the COVID-19 pandemic. Important developments in terms of public health, such as measures such as social distance and quarantine during the pandemic process, increased sensitivity to personal hygiene, and informing the public through various tools during the pandemic, are thought to be the reason for the decrease in the prevalence of intestinal parasites

Design and analysis of classifier learning experiments in bioinformatics: survey and case studies

PubMed ID: 22908127In many bioinformatics applications, it is important to assess and compare the performances of algorithms trained from data, to be able to draw conclusions unaffected by chance and are therefore significant. Both the design of such experiments and the analysis of the resulting data using statistical tests should be done carefully for the results to carry significance. In this paper, we first review the performance measures used in classification, the basics of experiment design and statistical tests. We then give the results of our survey over 1,500 papers published in the last two years in three bioinformatics journals (including this one). Although the basics of experiment design are well understood, such as resampling instead of using a single training set and the use of different performance metrics instead of error, only 21 percent of the papers use any statistical test for comparison. In the third part, we analyze four different scenarios which we encounter frequently in the bioinformatics literature, discussing the proper statistical methodology as well as showing an example case study for each. With the supplementary software, we hope that the guidelines we discuss will play an important role in future studies.The authors would like to thank the editor and the reviewers for their constructive comments, suggestions, pointers to related literature, and pertinent questions which allowed us to better situate our work as well as organize the manuscript and improve the presentation. This work has been supported by the Turkish Scientific Technical Research Council (TUBITAK) EEEAG 109E186 and Bogazici University Research Funds BAP 5701Publisher's VersionAuthor Post Prin

Investigation of surface properties of boriding Co-Mg alloy containing 3.0% Mg

Bu çalışmada, %97 Co ve %3 Mg içeren Co-Mg alaşımına borlama işlemi gerçekleştirilmiştir. Co-Mg alaşım malzemesini üretmek için toz metalurjisi (TM) yöntemi kullanılmıştır. Bu yöntemde, Co ve Mg metal tozları kapalı kaplar içerisinde homojen bir şekilde karıştırılarak şekillendirilmeleri için özel olarak tasarlanmış silindirik kalıplara dökülmüştür. Tek eksenli preste 300 bar basınç altında preslendikten sonra Argon gazı atmosferi ortamında 530 °C sıcaklıkta sinterlenmiştir. Sinterlenerek üretilen numunelere sırasıyla sertlik, yoğunluk ve yüzey pürüzlülüğü testleri uygulanmıştır. Sertlik testi sonrası 123 HV0,05 değeri elde edilirken ölçülen yoğunluk değeri ise 4,95 gr/cm3 olarak bulunmuştur. Bu işlemler sonrasında numuneler kapalı fırın ortamında 850 ve 900 °C sıcaklık ve 1.5-4.5 saat değişen sürelerde borlama işlemi gerçekleştirilmiştir. Bu işlem sonrasında SEM ve XRD analiz çalışmaları yapılmıştır. Analiz sonrasında borür tabakaları 850 °C sıcaklıkta 1,5 saat sürede 55 µm olarak bulunurken en yüksek 900 °C sıcaklık 4,5 saat sürede 140 µm olarak ölçülmüştür. Borlanmış Kobalt-Magnezyum alaşımlarına uygulanan XRD analizi sonucunda CoB, Co2B ve Co fazları elde edilmiştir. Mg elementinin hızlı bozulma özelliğinden dolayı yapılarda kısmende olsa boşluklar oluşmuştur.In this study, Co-Mg alloying containing 97% Co and 3% Mg was performed. Powder metallurgy (TM) method was used to produce Co-Mg alloy material. In this method, the Co and Mg metal powders are poured into cylindrical molds, which are specially designed to be shaped by mixing homogeneously in closed containers. It was pressed under 300 bar pressure in uniaxial press and sintered at 530 ° C in atmosphere of Argon gas atmosphere. Sintered samples were subjected to hardness, density and surface roughness tests respectively. After the hardness test, it was found that the value of HV0,05 was 123 and the measured density value was 4.95 gr/cm3 . After these processes, samples were subjected to boring in 850 and 900 °C temperature and 1.5-4.5 hours in closed oven environment. After this process, SEM and XRD analyzes were conducted. After the analysis, the boride layers were measured as 55 µm in 850 °C for 1.5 hours and the highest 900 °C temperature was measured as 140 µm in 4.5 hours. As a result of XRD analysis applied to boriding CobaltMagnesium alloys CoB, Co2B and Co phases were obtained. Due to the rapid deterioration of the Mg element, some gaps were formed in the structures.Afyon Kocatepe Üniversitesi BAPK 17.MYO.05 no'lu proj