Investıgatıon And Optımızatıon Of The Effect Of Cuttıng Condıtıons And Cuttıng Tool Coatıng Type In Borıng Operatıon

Bileşenler üzerindeki delikler çoğu durumda montaj amaçları için gerekli olduğundan, delik delme süreçleri ile üretilen delikler çok dikkat gerektiren son derece önemli işlemlerdir. Bir plaka veya yüzey üzerine deliklerin hassas bir şekilde delinmesi, bu amaç için tasarlanmış, delik işleme tezgâhlarında matkap, rayba veya delik kateri denilen takımlar kullanılarak yapılır. Tolerans sınırı içerisinde olmasına rağmen, deliklerin yanlış geometrisi nedeniyle montaj sorunları ortaya çıkabilir. Ölçü bozukluğu, silindiriklik, dairesellik, pozisyon hataları gibi çeşitli boyutsal ve geometrik toleranslar bu tür montaj problemlerine neden olmaktadır. Bu araştırma, Al7050 T7451 alüminyum alaşımlı plaka malzemede önceden delinmiş deliklerin 12 mm çap ölçüsüne işlenmesiyle oluşturulan deliklerin boyutsal tamlığı, daireselliği, silindirikliği ve yüzey kalitesi üzerine delik işleme (veya baralama) parametrelerinin etkilerini belirleme üzerine yapılmıştır. Deneyler, kuru ve ıslak işleme koşulları altında hassas delik işleme kafası kullanılarak hassas delik delme tezgâhında gerçekleştirilmiştir. Deliklerin işlenmesinde iki farklı özelliğe sahip CCGT 060202 26G6 ve CCGT 060202F-AL KX kesici uçlar kullanılmıştır. Bu çalışmada, kesici uç tipi, soğutma sıvısı kullanımı, iş mili hızı (dev/dak) ve ilerleme oranı (inch/dev) delik işleme parametreleri olarak seçilmiştir. İş mili hızı ve ilerleme oranı üçer seviye, kesici uç ve kesme şartları iki seviyeye sahip olup, deney planı Taguchi L9(32) orthogonal düzene göre oluşturulmuştur. Dikkate alınan delik boyutsal tamlığı, daireselliği, silindirikliği ve yüzey kalitesi gibi kalite karakteristiklerinin her biri için ayrı analiz yapılmıştır. Ayrıca, işleme parametrelerinin her bir kalite karakteristiğine olan katkı oranını belirlemek için de Pareto ANOVA yöntemi uygulanmıştır. Bütün kalite karakteristikleri için en uygun kombinasyonlar bu sonuçlar ışığında elde edilmiştirSince the holes on the components are in most cases necessary for mounting purposes, the holes produced by drilling processes are extremely important processes that require a lot of attention. Precise drilling of holes on a plate or surface is done by using jig borer designed for this purpose by using tools called drill, reamer or boring tool. Though the tolerance is within limit, assembly problems could arise due to the improper geometry of these holes. Various dimensional and geometrical tolerances like cylindricity, circularity and position errors are responsible for such assembly problems. This research studied on determining the effects of boring parameters on the dimensional accuracy, circularity, cylindricity and surface quality of the hole produced by boring to 12 mm the diameter of the holes predrilled on AL 7050 T7451 aluminium alloy plate material. Experiments were carried out on a precision boring machine using a precise boring head under dry and wet machining conditions. CCGT 060202 26G6 and CCGT 060202F-AL KX inserts have two different quality features have been used for boring of the holes. In this study, insert type, using coolant, spindle speed (rpm) feed rate (inch/rev) has been selected as boring parameters. Spindle speed and feed rate have three levels, insert and cutting condition have two levels, and experimental plan has been created according to Taguchi L9(32) orthogonal array. Separate analyzes were made for each of the quality characteristics such as hole dimensional integrity, circularity, cylindricity and surface quality considered. In addition, Pareto ANOVA method was applied to determine the contribution rate of processing parameters to each quality characteristic. Optimum combinations for all quality characteristics are obtained in the light of these results. Scienc

Defence tactics against company takeovers: A conceptual study

Son zamanlarda şirket ele geçirmeleri bir şirketin kontrolünü sağlama ve yönetimini değiştirmede kullanılan yaygın bir araçtır. Ele geçirme, bir şirketin, diğer bir şirketin yönetiminin ya da ortaklarının istekleri dışında, şirket üzerinde kontrol ve mülkiyet elde etmek amacıyla hisse senetlerinin satın alınmasıdır. Şirketler arası birleşmeler her zaman tarafların karşılıklı anlaşması ve isteğiyle gerçekleşmemektedir. Ele geçirilmek istenen hedef şirketin yönetimi buna karşı çıkabilir. Hedef şirketin yönetimi bu girişimleri önlemek için ele geçirme teklifi öncesi ve sonrası olmak üzere temel olarak iki çeşit savunma taktikleri geliştirebilmektedirler. Bu çalışmanın amacı; şirketin ele geçirilme girişimlerini bertaraf etmeye yönelik şirket bünyesinde geliştirilen ele geçirme teklifi öncesi ve sonrası savunma taktiklerini ilgili literatürü dikkate alarak teorik olarak ortaya koymaktır. Kullanılan taktiklerin bir arada sunulduğu çalışmaların yeterli düzeyde olmayışı bu çalışmanın çıkış noktasını oluşturmaktadır. Bu bağlamda çalışmada öncelikle ele geçirme kavramı ve ele geçirmenin amaçları ayrıntılı olarak irdelenmiştir. Daha sonra ele geçirme girişimlerine karşı geliştirilen ele geçirme teklifi öncesi ve sonrası savunma taktikleri ele alınmıştır.Takeover attempt is a common means using so as to get under control and to change management in recent years. Takeover is an acquiring of stocks in order to obtain controlling and possession at company, out of the desires of other company's administration and partners. Mergers of inter-company mergings doesn't always occur with desire and mutual agreement. Management of target company may challenge to this takeover. Management of target company may develop pre-bid and post-bid defense tactics in order to prevent takeover enterprises. The aim of this study is to present theoretically the hostile pre bid-and post-bid defense tactics developed in the body of the company aiming at elimination of attempts of company takeovers considering related literature. Deficiency of the studies in which these tactics are used together has given light to this study. In this context, firstly basic takeover concept and aims of the takeover will be explicated in the study. And then, pre-bid and post-bid defense tactics developed against these takeover methods will be examined in the study

Petrol fiyatlarının Türkiye’de imalat işletmeleri yatırımları üzerine etkisi

Petrol günümüzün önemli enerji kaynaklarının başında gelmektedir. Petrol özellikle sanayi kollarını oluşturan işletmelerin üretim faaliyetlerini sürdürebilmeleri için kritik bir öneme sahiptir. Petrol bugün birçok farklı ürünün doğrudan ve dolaylı olarak hammaddesini oluşturmaktayken, üretim faaliyetlerinde yer alan makinelerin çalışmasında ise enerji kaynağı olarak kullanılabilmektedir. Bu noktadan hareketle bu çalışmada, petrol fiyatlarının işletme yatırımları üzerine etkisi Türkiye'de faaliyet gösteren imalat işletmeleri açısından araştırılmıştır. Çalışmada uluslararası ham petrol fiyatları ile çalışma kapsamındaki imalat işletmelerine ait bazı bilanço ve gelir tablosu verileri birlikte kullanılarak panel veri analizi yöntemiyle analiz edilmiştir. Çalışmanın sonucunda Türkiye'de imalat sektöründe faaliyet gösteren işletmeler açısından petrol fiyatlarının işletme yatırımları üzerinde istatistiki olarak anlamlı ve negatif yönlü bir etkisinin olduğu ortaya koyulmuştur.Nowadays oil is the leading energy source in the world. Oil has got a critical importance on manufacturing, specially, in industrial areas. Whilst oil, directly or indirectly, composes the raw material of various products, it is also used as an energy source in running machinery in the manufacturing process. In the scope of this study it is researched that the effects of oil prices on business investments from the view point of manufacturing firms, operating in Turkey. In this study, international crude oil price data and some balance sheet and income statement data about the firms within the scope of work, are analyzed using the panel data analysis. The results of the study show that oil prices have an avoidant and statistically significant effect for the businesses operating in the manufacturing sectors in Turke

Pension Funds' Characteristics And Performances: The Case Of Turkey

Türkiye'de Bireysel Emeklilik Sistemi 27 Ekim 2003 tarihinde faaliyete geçmiştir. Sistemin amacı, bireylerin emekliliğe yönelik tasarruflarının yatırımlara yönlendirilmesi ile emeklilik döneminde bireylere ek bir gelir sağlanmasıdır. Diğer taraftan, sistemde kurulan emeklilik yatırım fonları ile hem sermaye piyasalarının gelişmesine ve derinleşmesine hem de tasarrufların yatırımlara aktarılmasıyla ekonomiye katkı sağlanmaktadır. Bu çalışmada, Türkiye'de bireysel emeklilik yatırım fonlarının karakteristik özellikleri ile getirileri arasındaki ilişkinin ortaya konulması amaçlanmıştır. Bu amaçla kurumsal yatırımcı kimliği ile 29 adet emeklilik yatırım fonunun 2008:01-2012:12 dönemi verileri panel veri analiz yöntemleriyle analiz edilmiştir. Yapılan analizin sonucunda; emeklilik yatırım fonlarının getirisi ile fonların hisse senedi oranı, yaşı ve aracılık komisyonu giderleri arasında pozitif yönlü; fonların getirisi ile fonların yönetim ücreti, büyüklüğü ve riski arasında ise negatif yönlü ilişki tespit edilmiştir.Individual Pension System came into existence on 27 October 2003 in Turkey. The purpose of the system is to provide additional income to individuals during the retirement with the investment of individual retirement savings. In addition, the system with the established pension funds provides a major contribution to the economy with the development and deepening of capital markets and the transfer of savings to investments. The aim of this study is to investigate the relationships between the characteristics of the funds and the funds' returns by using the panel data analysis. To do so, 29 pension funds as institutional investors have been taken into consideration for the period between 2008 and 2012. Our analysis shows that there is a positive relation between the fund return and the stock ratio of portfolio of the fund, fund age and brokerage commission expenses but a negative relation between the fund return and management fees, size and standard deviation

СОЛНЕЧНЫЕ СИСТЕМЫ ТЕПЛОСНАБЖЕНИЯ

WOS: 000379157300095The aim of this study was to investigate potential therapeutic efficiency of ozone therapy in the treatment of experimental endometriosis in rats. Fifteen rats were divided into three groups, which were labeled as the (1) sham control, (2) the ozone (treated with intraperitoneal ozone-oxygen mixture) and (3) the GnRH-agonist (given single dose (1 mg) leuprolide acetate depot formulation) group. Endometrial implant activity of superoxide dismutase (SOD), malondialdehyde (MDA), interleukin-1 beta (IL-1 beta), IL-6, tumor necrosis factor-alpha (TNF-alpha), and vasculary endothelial growth factor (VEGF) were measured after ozone-therapy. Furthermore, peritoneal fluid activity of SOD, MDA, and TNF-alpha were also measured before and after ozone-therapy. Serum AMH levels of the rats those were given ozone-therapy and control groups were measured. The rats given ozone-therapy showed significantly reduced endometriotic implant volumes. After ozone-therapy, a significant increase in activity of SOD in peritoneal fluid was detected. Conversely, implant levels of SOD in rats given ozone therapy was found to be significantly decreased. Both peritoneal fluid and implant levels of MDA were significantly decreased after ozone-therapy. Implant levels of TNF-alpha, IL-1 beta, and IL-6 were significantly increased following ozone-therapy. VEGF levels of implant was found to be unchanged after ozone-therapy. Serum AMH levels of animals were given ozone-therapy and control groups were similar. The number of both primordial and preantral follicles were significantly decreased after ozone-therapy. However, the number of atretic follicles were similar in ozone-therapy and control groups. Repeated administration of ozone-oxygen therapy in non-toxic doses inhibits growth of endometrial implants

COVID-19 pandemic and the global perspective of Turkish Thoracic Society

It has been more than 3 months now since the first case of COVID-19 was reported in Turkey. Globally, the number of confirmed cases and deaths reached 9,653,048 and 491,128 respectively, as reported by 216 countries by June 27, 2020. Turkey had 1,396 new cases, 194,511 total cases, and 5,065 deaths by the same date. From the first case until today, the Turkish Thoracic Society (TTS) has been very proactive in educating doctors, increasing public awareness, undertaking academic studies, and assisting with public health policies. In the present report, social, academic, and management perspectives of the pandemic are presented under appropriate subtitles. During this critical public health crisis, TTS has once again demonstrated its readiness and constructive stance by supporting public health, healthcare workers, and the environment. This review summarizes the perspective of TTS on each aspect of the COVID-19 pandemic and casts light on its contributions

Franchismo

We aimed to obtain information about the characteristics of the ICUs in our country via a point prevalence study

Etiological agents of community-acquired pneumonia in adult patients in Turkey; a multicentric, cross-sectional study Etiological agents of community-acquired pneumonia in adult patients in Turkey; a multicentric, cross-sectional study * TUCAP (Turkish Co

ÖZET Despite recent advances in diagnosis, treatment and vaccination, community-acquired pneumonia (CAP) is still one of the most common infectious diseases worldwide. It remains a major cause of morbidity and mortality, and contributes significantly to excessive consumption of healthcare resources and related costs (1-4). In Turkey, a pneumonia rank 15 th among the 20 Etiological agents of community-acquired pneumonia in adult patients in Turkey; a multicentric, cross-sectional study 120 Tüberküloz most frequent acute and chronic diseases and is the 5 th leading cause of death (5). Despite the fact that a great number of microbial agents can cause CAP, often no specific etiological diagnosis is established at the time of initial treatment, and antimicrobial therapy is usually performed using an empiric approach in such patients (2). In order to administer micro-organism-guided treatment, it is necessary to determine the causative pathogens of CAP. The etiological agents of CAP may vary according to geographic area and patients´ underlying risk factors. Decisions on proper empiric antibiotic therapy will therefore depend on prospective epidemiological studies (3). Surveillance studies constitute an important tool for determining local and regional susceptibility patterns and guiding empiric antimicrobial therapy (6). The majority of studies that have investigated the microbial causes of CAP have been carried out with patients admitted to hospital. Only a few studies have been undertaken to determine the etiology of CAP in the ambulatory patient Only a few studies of the etiology of CAP have been performed in adult patients in an ambulatory setting in Turkey MATERIALS and METHODS Study Design Eight university hospitals from different geographical regions of Turkey between November 2003 and March 2005 were included in this multicentric, cross-sectional study. In selecting centers, the following features were sought: the ability to represent different geographical areas, the ability to perform the investigative procedures in the study protocol in an optimal manner, and facility in coordination. A Turkish Community-Acquired Pneumonia (TU-CAP) Study Group was coordinated under the Infectious Diseases and Clinical Microbiology and Chest Diseases and Tuberculosis departments of the Karadeniz Technical University Medical Faculty. TUCAP members belong to infectious diseases and clinical microbiology departments or chest diseases and tuberculosis departments in the study centers. The study was approved by the Institutional Ethical Committee, and written informed consent was obtained from all patients or their legal representatives before enrolment. Patients The study population consisted of adult CAP patients > 17 years old and who attended an outpatient clinic at one of the study centers. Patients consisted of individuals living in urban as well as rural areas. All patients had clinical features and radiological findings compatible with CAP. CAP was defined as an acute illness associated with at least one of the following criteria; fever (> 38°C) or hypothermia (< 36°C), new cough with or without sputum production, pleuritic chest pain, dyspnea or altered breath sound on auscultation, plus a chest radiograph showing an opacity or new infiltrate consistent with pneumonia (11). CURB 65 score was used to determine disease severity (12). Patients with a diagnosis of immunosuppressive disorder, tuberculosis, health care associated pneumonia, aspiration pneumonia, antibiotic use in the last 48 hours, transferred from any health institution, hospitalization within the previous 2 weeks or pregnancy were excluded. Demographic and clinical data were collected by an investigator using a standardized questionnaire. In order to establish microbial etiology, sputum, nasopharyngeal aspirate, blood and urine samples were taken from the subjects. All samples were collected before the start of antibiotic therapy. Acute serum samples were collected on admission, and convalescent serum samples 2 and 4 weeks after initial diagnosis of CAP. Microbiological Evaluation Sputum and nasopharyngeal aspirate samples were investigated using Gram's stain and then cultured. Only sputum samples with > 25 white blood cells and < 10 squamous cells/per lowmagnification field (X10) were evaluated. Nasopharyngeal aspirate samples were also investigated for adenovirus, influenza A and B, parainfluenza viruses and respiratory syncytial virus Köksal İ, Özlü T, Bayraktar Ö, Yılmaz G, Bülbül Y, Öztuna F, Çaylan R, Aydın K, Sucu N, TUCAP Çalışma Grubu. 121 Tüberküloz Criteria for Etiological Diagnosis The following criteria were used to determine etiology: Cases that did not fulfil these diagnostic criteria were interpreted to be "No etiology determined". Statistical Analysis The chi-square test was used. p< 0.05 was regarded as statistically significant. RESULTS Two hundred ninety-two CAP patients were enrolled, of whom 218 were eventually analyzed. Seventy-four patients were excluded from analysis due to failure to obtain paired serum samples or to meet eligibility criteria, or else due to incomplete data. The mean age of enrolled patients was 57.5 ± 17.6. Ninety-four patients (43.1%) were older than 65. One hundred forty-seven patients were male and 71 female. All of patients had CURB-65 < 2. One hundred forty-two of the 218 patients (65.1%) had at least one comorbidity. The main demographic characteristics of the patients were summarized Etiological agents of community-acquired pneumonia in adult patients in Turkey; a multicentric, cross-sectional study 122 Tüberküloz ve Toraks Dergisi 2010; 58(2): 119-127 Two pathogens were identified in 22 (10.1%) of the 26 patients with mixed pathogens and 3 pathogens in 4 (1.8%) patients. The most frequent combinations were a bacterial pathogen plus a viral pathogen. S. pneumoniae was determined in 9 patients with mixed pathogens. H. influenzae was the second most frequent bacteria in mixed infections, in all cases together with a viral agent. Chronic obstructive pulmonary disease (COPD) was the most frequent comorbid factor, occurring in 42.7% of patients (93 out of 218). Other comorbidities were hypertension (29.8%), congestive heart failure (9.6%) and diabetes mellitus (8.7%). Seventy-eight pathogens were determined in 51 COPD subjects. The 4 most common pathogens were S. pneumoniae (27.4%), RSV (25.5%), H. influenzae (17.6%) and M. pneumoniae (17.6%). When the distribution of the microorganisms by age was evaluated, the most frequent pathogen in patients ≥ 65 was S. pneumoniae (17.0%), followed by RSV (13.8%) and M. pneumoniae (8.5%). In patients < 65, the most frequent agent was M. pneumoniae (17.7%), followed by S. pneumoniae (12.9%), H. influenzae (7.3%) and RSV (7.3%). Pneumonia caused by Streptococcus spp. and P. aeruginosa was observed in individuals aged > 65, though these agents were not encountered in subjects aged < 65 (p= 0.016; p= 0.037). Pneumonia due to atypical agents was greater in subjects aged < 65 (p= 0.034) ( DISCUSSION In this cross-sectional study conducted in Turkey, we determined etiology in 62.8% of patients with CAP. Levels of determination of the causative micro-organisms in CAP in the literature vary from 16% to 65% (13-27). In previous small studies in Turkey, the levels of etiological agents in pneumonia have been reported as, variously, 21% and 45.5 % of patients with CAP In our study, typical pneumonia agents were demonstrated in 35.8% of patients, atypical pneumonia agents in 20.2% and viral pneumonia agents in 20.6%. Mixed pneumonia agents were determined in 11.9% of patients. These proportions have been reported as 40%-54% for typical pathogens, 8%-63% for atypical pathogens and Köksal İ, Özlü T, Bayraktar Ö, Yılmaz G, Bülbül Y, Öztuna F, Çaylan R, Aydın K, Sucu N, TUCAP Çalışma Grubu. 123 Tüberküloz ve Toraks Dergisi 2010; 58(2): 119-127 4%-39% for mixed pathogens in different studies Major identifiable pathogens of CAP include S. pneumoniae, H. influenzae and atypical pathogens such as M. pneumoniae, C. pneumoniae and Legionella spp. In the present study, M. pneumoniae was the most frequent atypical pathogen and the second most frequent agent in the etiology of CAP. Some other studies have also reported M. pneumoniae as the most frequent atypical agent 124 Tüberküloz ve Toraks Dergisi 2010; 58(2): 119-127 nostic methods (28). The proportion of atypical pneumonia in other studies has varied from 8% to 63% We determined respiratory viral agents in 20.6% of patients. RSV has been determined as the third most frequent pathogen and the most common viral pathogen at all ages. In patients ≥ 65 it is the second most frequent agent. In recent years, RSV and other respiratory viruses have been detected more often in CAP patients due to use of new diagnostic methods. In different studies the level of respiratory virus has varied from 9% to 63% L. pneumophila was diagnosed in 2.3% of cases, which agrees with results obtained from previous studies (30). The incidence of Legionella spp. is reported to vary from 0.6% to 12.2% in sporadic CAP cases. A comprehensive study from Korea reported that L. pneumophila is one of the most common atypical pathogens of CAP around the world (28). Enterobacteriaceae (E. coli, K. pneumoniae) spp. and P. aeruginosa rarely cause CAP (30). In our study these pathogens were isolated as the least common microorganisms (1.8%, each). In our study, mixed pathogens were found in 11.9% of patients. Co-infection rates have been reported in 22.5%, 12.5%, 16%, 8.5% and 5.7% of CAP in other studies In CAP, the pattern of causative agents depends on age (33). Fifty-seven percent of the 218 patients in our study were younger than 65. In Turkey, the 15-64 age group represents 67% of the population (Turkish Statistical Institute, General Population Census and Economic Data, 2009). While S. pneumoniae was determined at the same rate in both groups, atypical pathogens were found less often in the elderly compared to younger patients. In elderly patients, the most frequent pathogen was S. pneumoniae (17.0%), followed by RSV (13.8%) and M. pneumoniae (8.5%). Viral pathogens have recently been increasingly diagnosed in elderly patients. In this study, as in others, M. pneumoniae was the most common pathogen in younger patients (30). Lim et al. reported atypical pathogen levels of 16% in elderly patients and 27% in younger patients (17). In this study COPD was the most important comorbidity. COPD has also been reported as the most common co-morbidity with CAP in other studies (30). The most important limitation in our study was the small number of CAP patients. Because university hospitals are tertiary referral centers, and because we excluded all patients who had received prior antibiotherapy, the number of CAP patients enrolled in this study was inevitably low. Köksal İ, Özlü T, Bayraktar Ö, Yılmaz G, Bülbül Y, Öztuna F, Çaylan R, Aydın K, Sucu N, TUCAP Çalışma Grubu. 125 Tüberküloz ve Toraks Dergisi 2010; 58(2): 119-127 Etiological agents of community-acquired pneumonia in adult patients in Turkey; a multicentric, cross-sectional study 126 Tüberküloz ve Toraks Dergisi 2010; 58(2): 119-127 In conclusion, a causative pathogen was demonstrated in 62.8% of patients with CAP. S. pneumoniae, M. pneumoniae and RSV were the 3 most frequent agents in adults with CAP in an ambulatory setting in this Turkish study. These results suggest that in patients with CAP in initial empiric therapy should cover S. pneumoniae and atypical pathogens. Our results showed that in the empirical treatment of CAP suggestions of the Turkish Thoracic Society consensus report are suitable and cover etiological agents of CAP for our country (34). Conflicts of Interest None of the authors had any financial or personal relationships with other individuals or organizations that might inappropriately influence their work during the submission process. ACKNOWLEDGEMEN