Energy dissipation characteristics of slab type buildings with special connectors

The latest developments in the construction technologies and the materials facilitated the practicing engineers to go higher and energy-efficient buildings. However, the safety of the buildings and the residents has been an issue all the time. This is not an exception for the precast structures. The advantages of the precast elements are the quality assurance and the rapid erection on the site and challenged by the connection details and their performances during the extreme loading cases such as earthquakes. The utilization of a special mechanical connection of the precast members have been in the focus of the recent works in Istanbul Technical University (ITU-STEELAB). The prototypes of the proposed special connectors, called as cushion, were tested in STEELAB in order to determine the mechanical properties such as lateral and axial stiffness and the failure modes. Once the properties were determined, a hypothetical building of single story multi-bay slab type structure was modeled in the computer framework capable of substituting various parametric values into the model, processing and extracting the results for statistical analysis, SAMA. SAMA is developed based on the use of SAP 2000 OAPI functions called in MATLAB and Python scripts. In the hypothetical model, the cushions were modeled as link elements and placed between all the precast elements including foundation-cladding interface. Extensive non-linear time-history analysis was conducted to identify the damage localization by comparing the energy dissipation at each mechanical connector under ground motion records selected according to focal distance, site conditions and intensity. The preliminary results reveal that the cushions are effectively dissipating a significant amount of energy and mitigating the collapse of the precast elements. The more detailed conclusions will be discussed in the near future.Publisher's Versio

The effect of stabilized wastewater sludge on nitrogen and urease activity in a soil

Bu çalışmada, farklı yöntemlerle stabilize edilen çamurların uygulandığı topraklarda çeşitli azot formları ve üreaz aktivitesi değerlerinde meydana gelen değişimler belirlenmiştir. Evsel nitelikli ham arıtma çamuruna, patojen popülasyonunu değişen derecelerde azaltan dört farklı stabilizasyon yöntemi (havada kurutma, pastörizasyon, kireç stabilizasyonu ve kireç+kül stabilizasyonu) uygulanmıştır. Stabilize edilen arıtma çamurları 50 ve 100 ton ham kuru çamur ha-1 oranını sağlayacak şekilde 2 tekrarlamalı tesadüfi blok tasarımı düzeninde 500 g kuru toprak içeren kaplara eklenmiştir. Örnekler 28ºC’de 34 gün boyunca inkübe edilmiştir ve inkübasyonun 5, 8, 15, 22, 29 ve 34. günlerinde alınan örneklerde toplam azot, amonyum azotu ve nitrat azotu konsantrasyonları ile üreaz aktivitesi seviyeleri belirlenmiştir. Uygulanan havada kurutma, pastörizasyon, kireç stabilizasyonu ve kireç+kül stabilizasyonu yöntemleri, çamurun fekal koliform içeriğini önemli derecede (4.12 ila 7.74 log) azaltmıştır. Uygulanan stabilizasyon yöntemleri USEPA kriterleri çerçevesinde değerlendirildiğinde, kurutma, kireç stabilizasyonu ve kireç+kül stabilizasyonu yöntemlerinin B sınıfı biyokatı oluşturduğu sonucuna varılmıştır. Diğer yandan, çamurun pastörize edilmesi (70ºC’de 30 dk.) ile USEPA A sınıfı biyokatı kriterleri sağlanmıştır. Sonuçlar çamura uygulanan stabilizasyon yöntemlerinin arasındaki farkların, toprakların toplam azot konsantrasyonu ve üreaz aktivitesi değerine olan etkisinin önemsiz olduğunu göstermiştir. Diğer taraftan, çamur uygulanan topraklarda belirlenen amonyum ve nitrat azotu değerlerinin ise çamura uygulanan stabilizasyon yöntemlerine bağlı olarak değiştiği tespit edilmiştir. İnkübasyon sonuçları özellikle alkali çamur uygulanan topraklarda, nitrifikasyon prosesinin amonifikasyona göre daha hızlı yürüdüğünü göstermiştir. Anahtar Kelimeler: Arıtma çamuru, azot formları, çamur stabilizasyonu, üreaz aktivitesi, toprak.Wastewater sludge has been already utilized in agricultural applications for several years as it represents an alternative source of nutrients for plant growth and an efficient soil conditioner enhancing certain physical properties of soil. However, wastewater sludge may contain pathogenic organisms and pollutants. This may negatively affect the soil properties. Recently increased attention was paid to the sludge stabilization process aiming to reduce the microbial content of sludge (pathogens). In this context several methods, such as biological digestion, composting, lime stabilisation, heat treatment have been used to eliminate pathogens from sludge. In this research, variations of various nitrogen forms and urease activity values have been determined in soils amended with wastewater sludges treated with different stabilization methods. Raw domestic sludge samples were treated with four different stabilization processes (air drying, pasteurization, lime stabilization and lime+fly ash stabilization) for reducing pathogen population with varying efficiency. Details of the processes are given below: air drying process: sludge was dried at 35°C by using a supplemental heat source; pasteurization: sludge was heated at 70°C for 30 minutes; lime stabilization: sludge was mixed with 15% of lime(CaO) on dry-weight basis; lime+fly ash stabilization: lime (10%)-fly ash (40%) mixture was added to sludge to increase the pH to 12. Lime is considered as one of the most common amendment materials for sewage sludge stabilization, as it plays significant role in reducing the microbial content of sludge (pathogens), enhancing the agricultural benefits and lowering the respective environmental risks. Fly ash, i.e. the by-product produced from fossil fuel thermal power plants, may contain increased amounts of calcium and magnesium oxides, depending upon the coal sources and may present highly alkaline values similar to lime. Thus, fly ash can be used as an alternative material for sludge stabilization with additional benefits, such as the reduced purchasing cost, and the minimization of fly ash disposal cost. Furthermore, the combined addition of fly ash and lime in small dosages to sewage sludge may result to an efficient removal of pathogens. In this research, de-watered sludge sample was collected from the treatment plant of canned food industry. The fly ash used in this study was obtained from Orhaneli Power Station where lignite is used for fuel. Technical grade anhydrous calcium oxide (quicklime 96%) was used together with fly ash in alkaline stabilisation. Stabilized sludge samples were amended to soil pots (500 g air dried soil) at rate equivalent to 50 and 100 tons dry sludge ha-1 and the pots were then arranged in a randomized block design with two replicates. The samples were incubated at 28°C for 34 days and total-N, ammonium-N and nitrate-N concentrations and urease activity levels were determined at 5, 8, 15, 22, 29 and 34 days of incubation period. Fecal coliform numbers were determined by Most Probable Number Method of Standard Methods. Concentrations of nitrate-N and ammonium-N were determined in samples which were extracted using 2 M KCI. The concentrations in extracts were analyzed by steam distillation with MgO and devarda alloy. Total N contents were measured by Kjeldahl digestion method. The urease activity of the soil was determined as described by Tabatabai. Applied methods of air drying, pasteurization, lime stabilization and lime+fly ash stabilization significantly decreased (4.12 to 7.74 log) the fecal coliform contents of wastewater sludge. When applied stabilization methods were evaluated by USEPA criteria, it can be concluded that air drying, lime stabilization and lime+fly ash stabilization generated Class B biosolid products. On the other hand, Class A biosolid requirements were achieved by pasteurization of sludge(70°C for 30 min.). The results indicated that the effects of applied sludge stabilization methods on total N concentration and urease activity values of soils were found to be insignificant. However, the ammonium and nitrate nitrogen concentrations in sludge amended soils were dependent on the applied sludge stabilization methods. In general, low levels of ammonium and high levels of nitrate nitrogen were determined in sludge amended soils during the incubation period. The results of the incubation indicated that nitrification proceeded much faster than ammonification especially in soils amended with alkaline sludges. Keywords: Nitrogen forms, sludge stabilization, soil, urease activity, wastewater sludge

Contrubition of Laparoscopic Level Determination on Hirschsprung Disease Diagnosis and Management

Aim:Laparoscopic-assisted transanal pull-through (LATP) is a procedure that has gained increasing popularity in the management of Hirschsprung’s disease. The purpose of this study was to compare outcomes of patients treated with LATP and transanal pull-through (TPT).Methods:Records of 45 patients with Hirschsprung’s disease who underwent surgery between 2006 and 2017 were retrospectively evaluated.Results:LATP was performed in 16 patients [13 male (81%), three female (19%)]. The median age of the patients was four months (7 days-84 months). Twenty nine patients [21 male (72.4%), eight female (27.6%)] underwent TPT. The median age of the patients was 11 months (10 days-90 months). The mean time to start feeding in LATP and TPT groups was two days (one-three days) and 2.6 days, respectively (p=0.074). The mean operative time was 2.6 hours in the LATP group (two-four hours) and 2.7 hours in the TPT group (p=0.971). The mean length of hospital stay in for LATP and TPT groups was 4.8 days (two-nine days) and six days (3-14 days), respectively (p=0.305).Conclusion:The advantages of LATP include multiple sample collection from several segments of the colonn at the same time as well as shorter time to frozen section diagnosis. In addition, the possibility of intraabdominal dissection allows transanal surgery to be faster and more effective

Nekrotizan enterokolitli yirmi üç hastanın klinik değerlendirilmesi

TEZ2418Tez (Uzmanlık) -- Çukurova Üniversitesi, Adana, 1982.Kaynakça (s. 93-102) var.102 s. ; res. ; 30 cm.

51CrV4 Yay çeliğinde ısıl işlem ve kesit geometrisinin çarpışma dayanıklılığı üzerine etkisi

In this study, 51CrV4 spring steel was used as a crash box material and its crashworthiness was investigated under axial dynamic loading. Crash boxes with cylinder and square geometries were designed in SolidWorks and crash analyses were performed by using RADIOSS/explicit and nonlinear Finite Element (FE) codes. In addition, 51CrV4 spring steel was subjected to three different heat treatments and their mechanical properties were determined by tensile and hardness tests. The crashworthiness of crash box was evaluated taking into account the energy absorption (EA), peak crushing force (PCF), mean crushing force (MCF) and crash force efficiency (CFE). Since the crash boxes had equal mass, their EA rates are equal to specific energy absorption (SEA) rates. It has been observed that heat treatment and cross-section geometry have a serious impact on crashworthiness.Bu çalışmada, 51CrV4 yay çeliği çarpışma kutusu malzemesi olarak kullanılmış ve çarpışma dayanıklılığı araştırılmıştır. Kare ve silindir kesit geometrisine sahip çarpışma kutuları SolidWorks programında tasarlanmış ve RADIOSS açık zaman entegrasyon yöntemi ve lineer olmayan sonlu elemanlar kodları ile çarpışma analizleri gerçekleştirilmiştir. Buna ek olarak, 51CrV4 çelik malzemesi 3 farklı ısıl işleme maruz bırakılarak mekanik özellikleri çekme ve sertlik testleri ile belirlenmiştir. Belirlenen mekanik özelliklere sahip yapının çarpışma dayanıklılığı, emilen enerji, maksimum çarpışma kuvveti, ortalama çarpışma kuvveti, çarpışma kuvveti verimi dikkate alınarak değerlendirilmiştir. Çarpışma kutularının kütleleri eşit olduğundan emilen enerji oranları özgül enerji emilim oranlarına eşittir. Isıl işlem uygulamasının ve kesit geometrisinin çarpışma dayanıklılığı üzerinde ciddi bir etkisi olduğu gözlemlenmiştir.ÖNERLER Compan

A new software on TUG-T60 autonomous telescope for astronomical transient events

Robotic telescopes usually run under the control of a scheduler, which provides high-level control by selecting astronomical targets for observation. TUBITAK (Scientific and Technological Research Council of Turkey) National Observatory (TUG)-T60 Robotic Telescope is controlled by open-source OCAAS software, formally named Talon. This study introduces new software which was designed for Talon to catch GRB, GAIA and transient alerts. The new GRB software module (daemon process) alertd is running with all other modules of Talon such as telescoped; focus, dome; camerad and telrun. Maximum slew velocity and acceleration limits of the T60 telescope are enough fast for the GRB and transient observations

The relationship between ABO blood group and blood transfusion in upper gastrointestinal bleeding

Introduction: ABO blood group (BG) antigens found in many cells and tissues, especially in erythrocytes, have been associated with many diseases including cardiovascular diseases, infections, and malignancies. The association of ABO BG with duodenal and gastric ulcers and upper gastrointestinal bleeding (UGB) has been investigated in few studies and the information on this subject is limited. The primary objective of our study is to examine whether there is an association between ABO BG and UGB, and the secondary objective is to examine whether there is an association between ABO BG and UGB in patients who received blood transfusions after bleeding. Methods: The prevalence values of A, B, AB, 0 BG and Rh antigens, endoscopic procedure, and blood transfusion information of patients who were diagnosed with UGB by endoscopic examination and hospitalized were recorded. Healthy individuals without UGB in the same period were included as the control group (CG). Those who had UGB by endoscopic examination constituted the study group (SG) while those who received at least 2 units of blood transfusion formed the transfusion group (TG). Results: SG consisted of 423 patients, TG included 383 patients, and CG had 1650 individuals. While the risk of bleeding was higher in SG patients with BG 0 (OR 1.33 1.07-1.66 P=0.009), the bleeding risk was lower in SG patients with BG B (OR 0.77 0.63-0.95 P=0.014). In addition, while the risk of bleeding was higher in TG patients with BG 0 (OR 1.35 1.08-1.70 P=0.009), the bleeding risk was lower in TG patients with BG B (OR 0.55 0.38-0.79 P=0.001). There was no statistically significant difference in SG, and TG in other BG A and AB and no significant difference in Rh. Conclusion: While UGB is more common in individuals with BG 0, it is less common in individuals with BG B. The risk of need for blood transfusion during the follow-up period of these patients in the ward is higher in patients with BG 0 but lower in patients with BG B. Keywords: Blood group, bleeding, transfusio