Obüs namlusu yanma odasında atış esnasında ortaya çıkan gerilmelerin matematiksel modellenmesi ve analizi

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.Türkiye Cumhuriyeti Devleti'nin jeopolitik ve jeostratejik konumu düşünüldüğünde savunma sanayinin gelişmesi son derece önem arzetmektedir. Bu düşünce ile hızla gelişmekte olan Türk Savunma Sanayi özellikle zırhlı tırtıllı araç ve silah üretiminde oldukça ciddi başarılara imza atmaktadır.Savaş ve barış durumunda oldukça kritik görevleri olan Modern Kundağı Motorlu Obüsleri hem tırtıllı araçlar, hem de uzun mesafelere görmeyerek atış yapabilen ağır silahlar olarak düşündüğümüzde, bu silahlarda namlu tasarımının ne derece önemli olduğu rahatlıkla görülebilir.Bu çalışmada Türkiye'de üretilmekte olan ve ağır silah sınıfına giren Kundağı Motorlu Obüs namlusu incelenmiştir. İncelenmede atış esnasında namludaki en fazla gerilmenin olduğu namlu yanma odasına etki eden gerilmelerin matematiksel modeli çıkarılmış, farklı sevk barutlarının kullanıldığı atışlardan elde edilen anlık namlu iç basınç değerleri kullanılarak, farklı malzemelerden üretilen namluların yanma odalarına etki eden gerilme değerleri ve yanma odalarındaki toplam deformasyon değerleri zamana bağlı olarak yapılan analizler neticesinde elde edilmiştir.Elde edilen sonuçlar, sonuçlar ve öneriler bölümünde tartışılarak daha sonra bu konuda çalışmak isteyen araştırmacılara kaynak olunmaya çalışılmıştır.Development of Defence Industry is really important if we think about the Turkey?s geopolitical and geostrategic position. With this thought, rapidly developing Defence Industry succeed especially in manufacturing armoured tracked vehicles and weapons.If we think about Modern Self-Propelled Howitzers which have a critical role in war and peace times as heavy weapons that can fire indirectly to both tracked vehicles and long range distances, it could be easily seen that gun barrel design is extremely important in these weapons.In this work, gun barrel of Self-Propelled Howitzer which is manufactured in Turkey and classified as heavy weapon is studied. In this study, mathematical model of stresses affecting combustion chamber which has the most stress in the gun barrel during the fire is made. With the use of gun barrel?s instantaneous internal pressures which is taken from the fires that different types of propelling charge is used, stress values that affect gun barrel?s combustion chamber manufactured by different type of materials and total deformation values in combustion chamber is obtained by the time-dependant analysis.Obtained results is discussed in the ?Results and offers? section and it is tried to develop a basis to the researchers who want to study in this topic

The impacts of timber harvesting techniques on residual trees, seedlings, and timber products in natural oriental spruce forests

The impacts of three timber harvesting techniques (manpower, skidder, and skyline) on residual trees, seedlings, and timber products were investigated in natural oriental spruce stands in Artvin, Turkey. Each of timber harvesting techniques was used in 5 different harvesting sites. The degree of damage caused by timber harvesting techniques in the residual trees, seedlings and timber products was calculated as based on injuring size. The results showed that timber harvesting techniques resulted in damages to residual trees, seedlings, and timber products, but the degree of damages caused by the harvesting techniques was significantly different. The highest level of damage was caused by manpower, followed by skidder and skyline harvesting technique. These results suggest that the damages caused by logging can be minimized by using proper timber harvesting techniques

EVALUATION OF HOSPITALIZED YOUNGEST-OLD, MIDDLE-OLD AND OLDEST-OLD COVID-19 PATIENTS IN TERMS OF MORTALITY AND RISK FACTORS

Introduction: In the coronavirus disease 2019 (COVID-19) pandemic, severe disease is predominantly seen in advanced-aged patients. In our study, we evaluated hospitalized youngest-old (65–74 years), middle-old (75–84 years) and oldest-old (≥85 years) COVID-19 patients in terms of mortality and risk factors. Materials and Methods: This retrospective study included hospitalized COVID-19 patients aged 65 years and older. Demographic characteristics, such as age, gender and comorbid conditions, baseline blood oxygen saturation levels, the necessity of oxygen treatments (nasal cannula,oxygen mask/reservoir oxygen mask), condition of the patients(mild, moderate, severe), baseline laboratory findings as C-reactive protein, white blood cell counts, thrombocyte counts, lymphocyte counts, D-dimer, alanine aminotransferase, aspartate aminotransferase and ferritin levels, pulmonary involvement on computerized tomography, the increase in oxygen requirements, the status of going to the intensive care unit and the status of receiving corticosteroids were recorded. Factors associated with mortality were analyzed. Results: A total of 399 geriatric COVID-19 patients were included in this study: 214(53.6%) were female and 185 (46.4%) were male. The mean age of the patients was 75±7.87(min:65–max:96). In our study, the mortality rate was found to be higher in the middle-old and oldest-old groups than in the youngest-old group (p=0.01). Other factors associated with mortality were as follows: lower baseline oxygen saturation levels (p=0.03), necessity of higher oxygen treatment (p<0.01), higher pulmonary involvement on computerized tomography (p<0.01), corticosteroid use (p<0.01) and having Alzheimer’s disease (p=0.03). Conclusion: Our findings emphasize that older patients are more vulnerable to COVID-19 infection and require special attention

Acute isoniazide intoxication. Case report

Akut isoniazid (INH) intoksikasyonu, epileptik nöbetler, koma ve metabolik asiden, triadı ile karakterime bir klinik tablodur. Özellikle yeterli öykü alınamadığı durumlarda, bu tablo ensefalit, meningoensefalit veya ensefalopati ile karışabilmektedir. Bu makalede ateş yüksekliği, bilinç kaybı ve status epileptikus tablosu ile prezante olan ve bu klinik bulguların etiolojisinde daha sonra INH intoksikasyonu saptanan, 19 yaşındaki olgu dolayısıyla, INH intoksikasyonun klinik ve laboratuvar bulguları ve ayırıcı tanı olasılıkları literatür bilgileri ışığında tartışılmıştır.Acute isoniazid (INH) intoxication is a clinicical case that is characterized by epileptic seizures, coma and metabolic asidosis triad. Especially in the conditions where sufficient history cannot be obtained, this case may be confused with encephalitis, meningoencephalitis or encephalopathy. In this article, the clinical and laboratory findings and the differential diagnosis probabilities of INH intoxication are discussed under the light of literature information because of a 19-year-old case who is presented with high fever, loss of conciousness and status epilepticus, in the ethiology of which INH intoxication was later detected

Hepatitis B and C Sero-prevalence in Patients with Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome at a Tertiary Care Hospital in Izmir

Objectives:\ud Infections caused by human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) represent a significant health problem. Co-infection with these viral agents is not uncommon as a result of the similar transmission routes. Our study was planned to investigate the prevalence of HBV and HCV infections in HIV/Acquired Immune Deficiency syndrome (AIDS) patients followed up at our institution.\ud \ud Materials and Methods:\ud In this study conducted in the Department of Infectious Diseases and Clinical Microbiology at Izmir Tepecik Training and Research Hospital, medical records of patients followed at the HIV/AIDS outpatient clinic between August 2002 and December 2014 were evaluated. Demographic data, main route of HIV transmission, hepatitis B surface antigen (HBsAg), anti-hepatitis B core (HBc) immunoglobulin G (IgG), anti-HBs and anti-HCV results were evaluated.\ud \ud Results:\ud A total of 157 treatment-naïve patients who were followed up at our HIV/AIDS outpatient clinic were included in this study. Four patients (2.6%), had HBsAg positivity. Anti-HBc IgG and anti-HBs positivity were detected in 34% and 28.4% of the patients, respectively. No patients had anti-HCV positivity.\ud \ud Conclusion:\ud The prevalence of HBsAg in HIV-positive individuals was found to be similar to that in other population-based studies in our country. Absence of anti-HCV positivity suggests that hepatitis C infection is not a major health problem in this population

Hepatitis B and C Sero-prevalence in Patients with Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome at a Tertiary Care Hospital in Izmir

Objectives:\ud Infections caused by human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) represent a significant health problem. Co-infection with these viral agents is not uncommon as a result of the similar transmission routes. Our study was planned to investigate the prevalence of HBV and HCV infections in HIV/Acquired Immune Deficiency syndrome (AIDS) patients followed up at our institution.\ud \ud Materials and Methods:\ud In this study conducted in the Department of Infectious Diseases and Clinical Microbiology at Izmir Tepecik Training and Research Hospital, medical records of patients followed at the HIV/AIDS outpatient clinic between August 2002 and December 2014 were evaluated. Demographic data, main route of HIV transmission, hepatitis B surface antigen (HBsAg), anti-hepatitis B core (HBc) immunoglobulin G (IgG), anti-HBs and anti-HCV results were evaluated.\ud \ud Results:\ud A total of 157 treatment-naïve patients who were followed up at our HIV/AIDS outpatient clinic were included in this study. Four patients (2.6%), had HBsAg positivity. Anti-HBc IgG and anti-HBs positivity were detected in 34% and 28.4% of the patients, respectively. No patients had anti-HCV positivity.\ud \ud Conclusion:\ud The prevalence of HBsAg in HIV-positive individuals was found to be similar to that in other population-based studies in our country. Absence of anti-HCV positivity suggests that hepatitis C infection is not a major health problem in this population

An abietane diterpene and two phenolics from salvia forskahlei

From the roots of Salvia forskahlei a new diterpenoid, forskalinone, two new aromatic compounds, the octanol esters of cis- and trans-4-O-methyl-caffeic acid dimers, were isolated together with the known compounds stigmast-3-one, sitosterol and alpha-amyrin. The structures of the new and the known compounds were established by spectral data. The antimicrobial activity of forskalinone and the dimeric cinnamic acid esters was tested against standard bacterial strains and a yeast, namely Bacillus subtilis ATCC 6633, Staphylococcus aureus 6538P, S. epidermidis ATCC 12228, Proteus mirabilis ATCC 14153, Escherichia coli ATCC 8739, Klebsiella pneumonia ATC 4352, Pseudomonus aeruginosa ATCC 9027, Enterococcus faecalis ATCC 29212, beta-haemolytic Streptococcus and Candida albicans ATCC 10231. Forskalinone showed moderate resistance against S. epidermidis (670 mu g ml(-1)) and slight activity against E. faecalis (168 mu g ml(-1)). trans-4-O-Methyl-caffeic acid dimer octanol ester was inactive while the cis isomer showed a slight activity against C. albicans (156 mu g ml(-1))