CERTAIN GEOMETRIC PROPERTIES OF A NORMALIZED HYPER-BESSEL FUNCTION

In the present paper, by making use of previous results on analytic functions, certain geometric properties including starlikeness of order α and convexity of order α of a normalized hyper-Bessel function have been investigated. In addition, some conditions of the mentioned function which belongs to the Hardy space have been given. Moreover, specific examples of the results which refer to special values of the parameters have also been presented

Left atrial mechanical function and stiffness in patients with atrial septal aneurysm: A speckle tracking study

Background: Atrial septal aneurysm (ASA) is a risk factor for arterial embolism. Atrial dysfunction and atrial arrhythmia, such as atrial fibrillation, might represent a mechanism for arterial embolism in such patients. Speckle tracking echocardiography (STE) is a novel and promising tool for detecting early changes in left atrial (LA) myocardial dysfunction. The aim of the study was to evaluate LA mechanical function and stiffness in ASA patients by 2-dimensional STE strain parameters. Methods: Thirty-four ASA patients (44.2 ± 12.3 years, 15 male) were studied, using a STE, and were compared with 31 age, gender, and left ventricular (LV) mass-matched controls (41.8 ± ± 11.5 years, 14 male). LA volume indices, mitral annular velocities, and global longitudinal LA strain were measured. The ratio of E/e’ to LA strain was used as an index of LA stiffness. Results: Patients with ASA showed increased LA volume indices and decreased LA global strain (25.3 ± 5.2 vs. 42.1 ± 8.7, p < 0.001). LA stiffness was increased in patients with ASA compared to the control subjects (0.41 ± 0.15 vs. 0.14 ± 0.05, p < 0.001), and LA strain and stiffness were related with LA volume indices. Conclusions: Patients with ASA have decreased LA global strain and increased stiffness, in comparison with those of the control subjects. LA strain and stiffness were significantly related with LA volume indices. LA stiffness and strain can be used for the assessment of LA function in patients with ASA

FARKLI BİYOKÜTLE SAPLARININ GAZLAŞTIRILMASI AMACIYLA LABORATUVAR TİPİ BİR GAZLAŞTIRICININ GELİŞTİRİLMESİ

Bu projede, bölgemizde yoğun olarak yetiştirilen çeltik ve kanola ürünlerinin hasattan sonra tarlada kalan saplarının gazlaştırılarak enerji içeriklerinin değerlendirilmesi için laboratuvar tipi bir gazlaştırıcı tasarlanmış ve imalatı yapılmıştır. Bölgeden toplanan çeltik ve kanola sapları peletlenerek biyokütle yakıt haline getirilmiş ve analizleri yapılmıştır. Geliştirilen gazlaştırıcının denemeleri çeltik ve kanola sapından imal edilmiş peletler kullanılarak başarıyla gazlaştırılmıştır. Gazlaştırma denemeleri sonucunda, kömür katkısının çeltik sapı peletleri için sentez gaz ısıl değerini arttırdığı (3,686 MJ/Nm3 değerinden 3,71 MJ/Nm3 değerine) ancak özgül gazlaşma hızının da artmasıyla beraber verime etkisinin olumsuz olduğu gözlemlenmiştir (katkısız peletlerde maksimum %61,9, kömür katkılı peletlerde ise maksimum %57,41) Kanola pelet örneklerinde kömür katkısı gazlaştırma parametreleri açısından olumlu etki yapmıştır (ısıl değer 7,15 MJ/Nm3 den 8,96 MJ/Nm3 değerine, ısıl etkinlik %68,85’den 81.51%’e yükselmiştir). Çeltik sapı peletlerinde içerdiği yüksek silisyum sebebiyle 800?C ve yukarı sıcaklık değerlerinde camlaşma riski taşıdığından dolayı yüksek gazlaşma hızlarına çıkılamamıştır. Kanola sapı peletleri ile çeltik sapı peletleri arasındaki performans farkının bu kadar fazla olmasının ana sebebi budur. Peletlenerek enerji yoğunluğu arttırılmış biyokütlelerin gazlaştırılması için ise tasarım sorunsuz bir şekilde çalışmış fakat peletlenmemiş, saman halindeki çeltik ve kanola saplarının gazlaştırılması için reaktör konstrüksiyonunun mevcut şekliyle uygun olmadığı, uygun olması için sürekli biyokütle besleme donanımlarını ilave edilmesi ve ebatlarda değişiklik yapılması gerektiği görülmüştür. Peletlenmemiş çeltik samanı için %37,14 gibi düşük bir verim elde edilirken, kanola samanında bu değer biraz daha yüksek elde edilerek %48,30 verime ulaşılmıştır. Aynı şekilde elde edilen singazın ısl değeride çeltik sapı için oldukça düşük (1.94 MJ/Nm3) bulunmuştur. Bu değer kanola samanı için 4,47 MJ/Nm3 olarak saptanmıştır. Özgül gazlaşma hızı ile verim ilişkisini gösteren grafikler değerlendirildiğinde; gerek kömür katkılı gerekse kömür katkısız olarak kanola sapından hazırlanmış peletlerin gazlaştırılmasında çeltik peletlerine göre çok daha yüksek özgül gazlaşma hızı önerilebileceği saptanmıştır.In this research, a laboratory scale gasifier was designed and manufactured for rice straw and canola straw to evaluate energy contents that collected from our region. Collected rice straw and canola straw from our region were prepared as biomass fuel by pelletizing and the pellets were analyzed. Experiments were realized by using rice straw and canola straw pellets and biomass samples were gasified successfully. As a result of the gasification experiments, it was observed that adding of coal powder to paddy stalk pellets increased the heat value of obtained syngas (from 3,686 MJ / Nm3 to 3.71 MJ / Nm3) while it has negative effect on the efficiency due to increaing of increasing specific gasification rate (maximum 61.9% for pellets withour coal powder and maximum 57.41% for coal powder added pellets). Adding of coal powder had a positive effect on the gasification parameters of the canola pellet samples (heat values increased from 7,15 MJ/Nm3 to 8,96 MJ/Nm3 while efficiency increased from 68,85% to 81.51%). Due to the high silicon content in the paddy pellets of the paddy, the high gasification rates could not be achieved due to the risk of glass structure at temperatures of 800 °C and above. This is the main reason why the efficiency difference between canola stalk pellets and paddy stalk pellets is so high. For gasification of pelltted biomass with increased energy density, designed reactor in this project worked smoothly. On the other hand, it has been determined that reactor construction is not suitable for the gasification of paddy and canola straws that were not pelletted and continuous biomass feeding systems should be included and changes in dimensions should be done. Lower efficiency was found for unpelletted paddy straw as 37.14% while higher value was determined for unpelletted canola straw as 48.30%. As parallel to this lower efficiency values compared to values determined for pelletted straws, heat values of syngas for unpelltted paddy straw was determined rather low (1.94 MJ/Nm3) compared to value for unpelltetd canola stalk as 4.47 MJ/Nm3. Graphs that showed that relationship between the specific gasification rate and the efficiency showed that higher specific gasification rate can be offered for gasification of both coal-added and without coal pellets prepared from canola straw compared to pellets prepared from paddy straws

A Prototype Downdraft Gasifier Design with Mechanical Stirrer for Rice Straw Gasification and Comparative Performance Evaluation for Two Different Airflow Paths

In this research, a prototype downdraft throatless gasifier was designed with a mechanical stirrer. The gasifier was designed for gasification of rice straw pellets. The diameter of the reactor was 350 mm and a nominal value for the heat power of biomass input was 70 kW. Rice straws which were collected from Thrace Region of Turkey gasified for determination of the designed gasifier performance in Namik Kemal University Biosystem Engineering Laboratories. The effects of airflow path and stirring process on the gasification efficiency during the gasification process were investigated. Temperatures and airflow rates observed and adjusted by controlling the air flow rate in the automation system constantly. Pellets were gasified using two different airflow paths with the same equivalence ratio of 0.2 and these were compared. Air inlet from the top showed better results than air inlet from tuyeres. For the air inlet from the top, the higher heating value of producer gas was determined as 5.047 MJ Nm(-3) and cold gas efficiency was calculated as 65.4%. H-2/CO ratio was found as 1.385 which was higher than the air inlet from tuyeres.TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113O434]We would like to thank TUBITAK for the supporting this project that numbered 113O434. The experimental gasifier laboratory established by this TUBITAK Project

The effect of varenicline on Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio in healthy smokers and nonsmokers

Background: Varenicline could affect the T wave and QT interval. The interval from the peak to the end of the electrocardiographic (ECG) T wave (Tp-e) may correspond to the transmural dispersion of repolarization, and increased Tp-e interval and Tp-e/QT ratio are associated with malignant ventricular arrhythmias. In this study, we assessed the effects of varenicline on Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio. Methods: Thirty healthy volunteers (15 healthy non-smokers [NS] and 15 healthy smokers [S]) were included in the randomized, double-blind, placebo-controlled, crossover study. Varenicline (2 mg single dose) or placebo was administered in two different testing sessions (5 days after the first period, performed the second period). Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio were assessed in the supine position and during handgrip exercise before and after the participants were given placebo or varenicline. Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio were calculated from continuous ECG recordings and averages were used in the final analysis. Result: There were no statistically significant differences among any of the Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio before and after placebo administration in both groups (S and NS). In the S group, Tp-e and QTc interval, and Tp-e/QT and Tp-e/QTc ratio were significantly increased after varenicline administration (Tp-e: 64.28 ± 8.78 vs. 70.42 ± ± 13.12; p = 0.02, QTc: 409.57 ± 28.17 vs. 425.28 ± 32.79; p = 0.02, Tp-e/QT: 0.18 ± 0.02 vs. 0.19 ± 0.03; p = 0.04, Tp-e/QTc: 0.17 ± 0.02 vs. 0.19 ± 0.02; p = 001) but these parameters were not changed in the NS group. Conclusions: Tp-e and QTc interval, and Tpe/QT and Tpe/QTc ratio were increased after varenicline administration in smoker