Evaluation of pressure-stiffness coupling in brush seals

Brush seals are comprised of fine diameter fibers densely packed between retaining and backing plates. To achieve seal compliance bristles are arranged to contact rotor with some lay angle. When axial pressure load is applied, bristles interlock and get stuck at the backing plate, and seal stiffness varies under operating conditions. Operating stiffness is critical to determine seal-rotor contact pressure and wear life. Typically, seal stiffness is measured by pressing a curved shoe to brush bore as reported in open literature. Due to the complex nature of pressure-stiffness bristle behavior, static and unpressurized measurements cannot represent actual working seal stiffness. This work presents a brush seal stiffness measurement system that is capable of measuring seal stiffness under working pressure and speed conditions. Rotor speed is achieved by an integrated spindle drive, while contact forces are measured via sensitive load cells. Rotor excursions are applied through lateral motions of the seal housing that is actuated by a motorized linear slide. Stiffness testing methodology and calibration procedure are discussed. Comparative experimental data are presented for both static pressurized and dynamic-pressurized stiffness tests

Leakage performance of a novel turbomachinery shaft seal

Advanced sealing systems are needed to control parasitic leakage flows to achieve high turbine engine efficiency and low emissions. Typical extreme turbomachinery engine operating conditions when combined rotor excursions do not lend simple sealing solutions. This work presents an in-depth analysis of a novel robust yet simple sealing system that is capable of maintaining long life under high speed and high temperature operating conditions. The proposed seal design is actually a gas bearing that is carefully tailored, analyzed, and designed to function as a differential pressure seal. The design involves a simple rigid/semi-flexible seal ring that is attached to a stationary support plate via flexible metal cloth structure. The seal body is capable of moving under the effect of hydrodynamic lift force. Therefore, above a certain clearance limit, which ensures that asperity contact is avoided, the seal follows shaft excursions to avoid damaging hard rubs

An application of prospect theory on analysis of strategic voting: the effect of incumbency on reference point/

Prospect theory is one of the most influential decision making theories in social sciences. However, it has been ignored by the literature of strategic voting in which expected utility theory is widely preferred. In this study, I apply two claims of prospect theory, reference point dependency and loss aversion, on the analysis of strategic voting. The purpose of this study is to understand the impact of voter’s reference point on the probability that a voter casts strategic vote in election. Hypotheses are derived from a formal model which incorporates reference point and loss aversion into the analysis of strategic voting. The model predicts that voters, whose most preferred party or candidate is the incumbent, are more prone to vote strategically than voters, whose least preferred party or candidate is the incumbent. In addition to this, when the place of the incumbent in preference ranking of the voter in which, voter ranks parties/candidates in order of preference, increases; probability of strategic voting increases as well. To test these predictions, experiments were conducted with student and farmer subjects. Also, statistical analyses were done with survey data from the 2015 British Election Studies (BES) for the 2010 and the 2015 UK General Elections. Results from experiments and statistical analyses provide support for predictions of this study

Osmanlı Devleti’nde Adliye Teşkilatının Bir Unsuru Olarak Mahkemeler

Osmanlı adliye teşkilatını; hukuk sistemi, hakimlik müessesesi ve mahkemeler olarak üç ana grupta incelemek mümkündür. Araştırma, mahkemelerin nitelikleri ve geçirdikleri değişimlerin kısa tarihini ortaya koymayı amaçlamaktadır. Osmanlı mahkemelerinin, şer’î mahkemeler olarak kuruluşundan itibaren Tanzimat sonrası yapılan reform ve ıslahat çalışmalarına değinilecektir. Bu dönemdeki düzenlemelerin en önemlilerinin adliye teşkilatında yapıldığı bilinmektedir. Osmanlı mahkemeleri, Osmanlı hukukunun bir sonucudur. Bu alandaki düzenlemeler de hukukun tatbikine, idari otorite tarafından verilmek istenen şekli yansıtmaktadır. Osmanlı idarecileri son yüz elli yıllık zaman diliminde, dönemin gerektirdiği ekonomik ve siyasi ihtiyaçları karşılamak için hukuki düzenlemelerin gerekli olduğunu kabul etmişlerdir. Bu düzenlemelerde halkın herhangi bir talebi söz konusu değildir. Sultanlar tarafından “ihsan” olarak sunulan ıslahatlar, yönetici sınıf tarafından planlanmıştır. İslam hukukunun ve şer’î mahkemelerin varlığına dokunulmadan yapılan bu düzenlemeler, vatandaşların tamamına uygulanabilecek, eşitliği sağlayabilecek, azınlıklar arasında yayılan milliyetçilik duygusunun önüne geçebilecek, egemenliğe mani olan kapitülasyonlara engel olabilecek bir set olarak görülmüştür. Yapılan tanzimat ve düzenlemeleri, günümüz Türkiye’si ve Osmanlı Devleti toprakları üzerinde sonradan kurulan devletler de örnek almışlardır. Dolayısıyla bu dönem mahkemeleri üzerinde yapılan çalışmalar bilinmeden, günümüz adliye teşkilatının problemleri hakkında çözüm sunabilmek kolay görülmemektedir. Çalışmada; kanunname ve nizamnameler ile birlikte hukuk tarihini inceleyen telif eserler değerlendirilmiştir

Response surface modeling of a small crossflow hydro turbine rotor

This paper presents the progress made in works aiming to design a modular low cost cross-flow turbine runner that is compatible with mass production. In an earlier study, stress and weight optimization analyses had been presented for a common runner design. This work includes analyses on segmented modular runner design iteration. Obtaining a closed form analytical formulation for complex mechanical structures such as turbine rotors with multiple blade assemblies can be very problematic. Building a prototype without optimizing the structural stress levels may result in unnecessary hardware costs. In this work, mathematical models for highest stress or lowest factor of safety on critical components of a small modular cross-flow hydro turbine rotor have been explored for various design options through a response surface analysis. The response surface model is obtained based on finite element analysis results following design of simulated experiments. Rotor design parameters have been investigated to optimize factor of safety on critical components without violating the specified weight limits. Box-Behnken data tables have been used to obtain the response surface model. The attained response model yields the maximum stress and lowest factor of safety for critical rotor components for various combinations of design parameters. Verification runs indicate that response model successfully predicts factor of safety levels close to finite element calculations

Coexistence of parathyroid adenoma and papillary thyroid carcinoma: Experience of a single center

Objective: The aim of this study was to describe experienceswith concurrent parathyroid adenoma and papillarythyroid carcinoma.Methods: Eight patients with concurrent parathyroid adenomaand papillary thyroid carcinoma were identifiedbetween 2005 and 2012, and their medical records werereviewed retrospectively.Results: Of the eight patients identified, two were maleand six were female; their mean age was 53.6 years.The mean serum calcium concentration was 11.7 mg/dL.Intact parathyroid hormone (iPTH) concentrations werehigh in all patients, with a mean concentration of 338 pg/mL. The most frequently used surgical technique was totalthyroidectomy plus parathyroid adenoma excision (n=6).The mean size of the thyroid carcinoma was 1.2 cm, andone case showed metastatic lymph nodes in the centralcompartment. The mean parathyroid adenoma size wasfound to be 2.1(0.6- 3.5) cm, according to the longest sizeof the adenom. Six patients (75%) developed postoperativecomplications, including temporary symptomatic hypocalcemiain 4 patients (50%), hematoma developmentin 1 patient (12.5%) and temporary vocal cord paralysis inone patient (12.5%).Conclusion: Thyroid carcinoma and parathyroid adenomaare rarely concomitant. Rarely hyperparathyroidismmay be accompanied with thyroid carcinomas so preoperativelythyroid gland should be properly examined. Thyroidwith parathyroid surgery are risk factors of recurrentlaryngeal nerve injury and hypoparathyroidism.Key words: Papillary thyroid cancer; parathyroid adenoma;thyroidectom

Memenin Granüler Hücreli Tümörü: Olgu Sunumu

Memenin granüler hücreli tümörü Schwann hücrelerinden köken alan nadir bir tümördür. Memede görülme oranı tüm granüler hücreli tümörlerin % 5-8’i kadardır. Memenin granüler hücreli tümörü saptanan 61 yaşında bir kadın hastayı sunmak istedi