Applicability of equal energy assumption to the out-of-plane response of steel arch bridges

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2005Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2005Japon Karayolu Köprüleri Deprem Yönetmeliği`nde büyük Kanto depremi, Kobe depremi gibi şiddetli depremlere karşı tasarım yöntemi olarak “Süneklik Tasarım Yöntemi” adında malzeme ve geometrik doğrusal olmayan davranışı göz önüne alan statik analizlere dayanan basitleştirilmiş bir tasarım yöntemi verilmektedir. Yöntemde maksimum doğrusal olmayan şekil değistirmelerin hesabında Eşdeğer Enerji Varsayımı kullanılmaktadır. Ancak bu varsayımın uygulanabilirliği çerçeve sistemli ayaklı köprüler, çelik kemer köprüler gibi karmaşık dinamik davranış gösteren yapılar için sınırlıdır. Bu sebeple Japon Deprem Yönetmeliği, yönetmelikte karmaşık köprü sınıfına giren bu tür köprülerin sismik tasarımı için zaman alıcı ve pahalı doğrusal olmayan dinamik analiz yöntemlerinin kullanılmasını zorunlu kılmıştır. Bu çalışmada eşdeğer enerji varsayımının tabliyesi kemer üzerinde bulunan çelik kemer köprülerin maksimum doğrusal olmayan davranışının hesabında kullanılabilirliği 6 model üzerinde, serbest titreşim, pushover ve de doğrusal ve doğrusal olmayan dinamik davranış analizi (time history) yapılarak denenmiştir. Modellerin oluşturulmasında taşıyıcı kemerlerin basıklığı ve de aralarındaki mesafe temel parametreler olarak seçilmiştir. Elde edilen sonuçlara göre hesaplanan şekil değiştirmeler güvenli tarafta olmasına rağmen birçok durumda hesaplanan değerler ekonomik güvenlik marjını aşarak gerçek şekil değiştirmelerin çok üzerinde bulunmuştur. Ancak varsayımın uygulanabilirliğine ilişkin bazı ilişkiler bulunmuş ve bu ilişkilere dayanarak bazı düzeltme fonksiyonları geliştirilmiştir. Bu fonksiyonların kullanılabilirliği çelik kemer köprü modelleri üzerinde numerik olarak gösterilmiştir.Japanese seismic design code for highway bridges specifies the Ductility Design Method, which is based on static analysis considering the material and geometrical non-linearity, as the design method against severe earthquakes like great Kanto Earthquake and Hyogo ken Nanbu Earthquake. The method employs Equal Energy Assumption for the prediction of maximum inelastic seismic response. However, the application of this method is limited because the applicability of equal energy assumption is not clear to some types of structures with complex dynamic behavior such as steel portal frame bridge piers and deck-type steel arch bridges. For these structures time taking and costly dynamic response analysis is required in the seismic design. In this study, the applicability of the Equal Energy Assumption to the out-of-plane inelastic response prediction of deck-type steel arch bridges is numerically evaluated for 6 models by performing eigenvalue analysis, pushover analysis, and elastic and inelastic dynamic response analysis. The models are generated by setting the Arch Rise/Span Length ratio and the distance between the arch ribs as the main structural parameters. Although safety side estimation was achieved by the assumption, the results were too conservative in many cases. For the applicability of the assumption some tendencies were found and correction functions were established to improve the accuracy. The validity of the proposed correction functions for the estimation of maximum inelastic seismic response without the need of inelastic dynamic response analysis was evidenced on the studied bridge models.Yüksek LisansM.Sc

(2Z,6Z)-N 2,N 2′-Bis(2,6-diisopropyl­phen­yl)-N 1,N 1′-bis­(2-methoxy­ethyl)pyridine-2,6-dicarboxamidine

In the title compound, C37H53N5O2, the benzene rings make dihedral angles of 84.61 (8) and 67.10 (9)° with the pyridine ring. The crystal structure is stabilized by strong intra­molecular inter­actions. The two (2-methoxyethyl)amine groups are disordered over two positions; the site occupancies are ca 0.6 and 0.4

Evaluation of Agreement Between Sweep Visual Evoked Potential Testing and Subjective Visual Acuity

Objectives:The primary objective of this study was to evaluate the agreement of visual acuity (VA) obtained with the sweep visual evoked potential (sVEP) method with the VA obtained with the Snellen chart. The secondary objective was to examine the effect of age and gender on agreement.Materials and Methods:Best corrected VAs of subjects were recorded with the Snellen chart, and sVEP testing was performed according to the recommendations of the International Society for Clinical Electrophysiology of Vision (ISCEV). Snellen VAs and sVEP measurements were analyzed using logMAR conversion for statistical analysis. Agreement was evaluated with Bland-Altman analysis.Results:The study included 49 subjects with a mean age of 53.5±17.3 years (range: 19-75 years) and mean Snellen VA of 0.31±0.32 logMAR (range: 1.3-0.0 logMAR). In the Bland-Altman analysis, the mean differences between the VA and sVEP measurements (VA-sVEP) were significantly different and outside the limits of agreement (p=0.035). A significant proportional bias (p=0.0007) was found in the regression analysis performed between VA-sVEP and the mean VA. According to the Bland-Altman analysis of sex subgroups, there was a significant difference between VA and sVEP measurements in female subjects (p=0.006). The difference between VA and sVEP measurement increased significantly with older age (R2: 0.306, p<0.001, β: 0.05 [0.03, 0.08]).Conclusion:In conclusion, sVEP measurements and VAs did not show statistical agreement. Cranial anatomy and endocrine differences of the subjects may affect their sVEP measurements. The difference between the methods varies according to VA level. Directly using sVEP results instead of VA would not be appropriate

IMPORTANCE OF SPORTS ACTIVITIES FOR OBESE YOUTH IN SOCIALIZATION PROCESS

The purpose of this study is to examine the contribution of sport to obese youth duringsocialization, considering the socio-cultural and economic characteristics of obese adolescents. In the study participated 118 obese children members of Ankara Metropolitan Municipality Family Life and Youth Centers who played sports or participated in sport activities in the 15-18 age range. As a data collection tool, the socialization scale consisting of 69 questions developed by Sahan (2007) was used. A computer-aided data analysis program was used in the research data. Frequency analysis was applied first and tables were made during the analysis of the data. The percentages of the variables in the sample were determined, and the characteristics of the sample were evaluated generally in these tables. Analysis procedures were applied according to hypotheses later. The data were evaluated by the Scheffe test, the Mann Whitney U test and the Kruskal-Wallis Nonparametric test. As a result of the research; it was found that there was no significant difference between the levels of socialization of obese youth according to the age variable and there was a significant difference between sexes, household income levels and the sports and socialization levels of obese youth who are interested and who are uninterested in sport. At the end of the research, it was observed that male obese teenagers had higher levels of socialization than female obese teenagers in terms of high income level and interest in sport

The predictors of COVID-19 mortality in a nationwide cohort of Turkish patients

he COVID-19-related death rate varies between countries and is affected by various risk factors. This multi center registry study was designed to evaluate the mortality rate and the related risk factors in Turkey. We retrospectively evaluated 1500 adults with COVID-19 from 26 centers who were hospitalized between March 11 and July 31, 2020. In the study group, 1041 and 459 cases were diagnosed as definite and highly probable cases, respectively. There were 993 PCR-positive cases (66.2%). Among all cases, 1144 (76.3%) were diagnosed with non-severe pneumonia, whereas 212 (14.1%) had severe pneumonia. Death occurred in 67 patients, corre sponding to a mortality rate of 4.5% (95% CI:3.5–5.6). The univariate analysis demonstrated that various factors, including male sex, age ?65 years and the presence of dyspnea or confusion, malignity, chronic obstructive lung disease, interstitial lung disease, immunosuppressive conditions, severe pneumonia, multiorgan dysfunction, and sepsis, were positively associated with mortality. Favipiravir, hydroxychloroquine and azithromycin were not associated with survival. Following multivariate analysis, male sex, severe pneumonia, multiorgan dysfunction, malignancy, sepsis and interstitial lung diseases were found to be independent risk factors for mortality. Among the biomarkers, procalcitonin levels on the 3rd-5th days of admission showed the strongest associations with mortality (OR: 6.18; 1.6–23.93). This study demonstrated that the mortality rate in hospitalized patients in the early phase of the COVID-19 pandemic was a serious threat and that those patients with male sex, severe pneumonia, multiorgan dysfunction, malignancy, sepsis and interstitial lung diseases were at increased risk of mortality; therefore, such patients should be closely monitored

10-14 YAŞ ÖĞRENCİLERİN FİZİKSEL AKTİVİTE VE FİZİKSEL UYGUNLUK DÜZEYLERİNİN ÖLÇÜLMESİ VE DEĞERLENDİRİLMESİ

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