DESIGN OF A PIEZOELECTRICALLY ACTUATED MICROVALVE FOR FLOW CONTROL IN FUEL CELLS

This thesis presents a novel piezoelectrically actuated microvalve for flow control in fuel cells. A fuel cell is an electrochemical device, which directly converts chemical energy stored in a fuel (e.g. hydrogen) and an oxidizer (e.g. oxygen) directly into electrical energy. Poor flow distributions within the cell have been attributed to degraded performance and even damage. In this study, it is proposed to embed microvalves directly into the fuel cells to manage the gas flows and improve efficiency, performance, and reliability. The microvalve has four parts. The actuator is a piezoelectric trimorph which has two piezoelectric layers and one brass layer sandwiched between them and has dimensions of 20000 x 4000 x 290 microns. It also has a valve gate placed on the tip. For a 5-volt input, a deflection of 32 microns can be achieved in the trimorph tip, which is what modulates the flow through the valve.The valve design and analysis are complete. Maximum stress on the bender reaches up to 60 Mpa when the the fluidic and thermal forces are at their maximum. This maximum stress is below the tensile dynamic strength values of piezoelectric and brass layers used. A minimum factor of safety of 1.5 is obtained at 20 degrees C. At the operating temperature, which is about 100 degrees C the factor of safety is higher since the stresses are much lower. The drag and pressure forces are found to reduce the free deflection by only 0.2 microns whereas the thermal expansion forces increases the deflection almost by the same amount. Finally detailed fabrication plan and drawings were completed

Kuzey Marmara otoyolu güzergahında bulunan yerleşmeler ve yolun yerleşmelere muhtemel etkileri - Sakarya ili örneği -

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Ulaşım, ekonomik ve sosyal yaşantıya büyük etkileri olan ekonomik faaliyettir. Özellikle, Asya ve Avrupa kıtaları arasında yer alan ülkemizde ulaşım faaliyetleri ülke ekonomisi için büyük önem taşımaktadır. Geçmişte ve günümüzde ulaşım ağları geçmiş oldukları yerleşmeleri sosyal ve ekonomik açıdan etkilemiştir. Bu etkiler kimi zaman yerleşmenin büyümesi, nüfuslanması, kimi zaman da ekonomik faaliyetlerin çeşitlenmesi veya değişmesi gibi çeşitli şekillerde görülmüştür.Bu tezde henüz proje aşamasında olan Kuzey Marmara Otoyolu güzergahı üzerindeki yerleşmeler incelenmiş ve otoyolun bu yerleşmeler üzerinde yapacağı muhtemel etkiler konusunda öngörülerde bulunulmuştur. Tez içeriğinde ilk olarak ulaşım ve yol kavramları üzerinde durulmuş, bu kavramların sosyal ve ekonomik etkileri belirtilmiştir. Ayrıca Cumhuriyet'ten günümüze Türkiye'deki ulaşım ağlarının gelişimi ve günümüzdeki mevcut durum ortaya konulmuştur. Tezin ikinci bölümünde Kuzey Marmara Otoyolu'nun tanıtımı ve bu yola neden ihtiyaç duyulduğu ve güzergah üzerindeki iller konusunda bilgi verilmiştir. Tezin üçüncü bölümünde Sakarya'da Karayolunun gelişimi ve Kuzey Marmara Otoyolu güzergahının Sakarya'nın fiziki ve beşeri alanları ile olan etkileşimi genel olarak özetlenmiştir. Dördüncü ve son bölümde tezin ana konusunu oluşturan otoyol güzergahı üzerindeki yerleşim alanları incelenmiştir. Yerleşim alanları incelenirken mevcut sosyal, ekonomik ve fiziki durum incelenmiş, ardından otoyolun yerleşim alanı üzerindeki muhtemel etkileri üzerinde durulmuştur.Yerleşimler incelenirken mülakat ve yerinde gözlem yöntemleri kullanılmıştır.Transportation is economical activity which has big effects on economical and social life. Especially transportation activities have got big importance for our country?s economy which is between Asia and Europe. In the past and now, transportation networks affected the settlemente where they go through. These effects were seen, sometimes enlarging of settlements, increasing of population and sometimes changing and diversfiying of economical activities.In this thesis, just being in project step, some settlements were searched which are North Marmara networks possible effects in settlements were considered. In this thesis, transportation?s and lines concepts were emplasized and these concepts effects on economical and social life were stressed. In addition to these, from republic to nowadays, developments of line and the situation which is in our days were ascertaired. In the second part of thesis, description of North Marmara?s highway and why do we need this line network and about some cities which are on this line, were informed. In the third part of thesis, development of Sakarya Network?s line and the effect of North Marmara Networks Line?s on Sakarya in terms of physical and human field were generally summarized. In the forth and the last part of the thesis the settlements were searched on the other hand social, economical and physical situations were searched and then dwelled on this networks possible effects on these settlements area.While the settlements were searched on interview and on observation on place methods were used

A review in terms of administrative geography: Afyonkarahisar province

Ege Bölgesi’nin İç Batı Anadolu Bölümü’ne yer alan Afyonkarahisar ili bulunduğu konum itibariyle Ege, Akdeniz ve İç Anadolu bölgelerine ait illerle çevrelenmiştir. Coğrafi konumunun etkisiyle bahsi geçen bölgeler arasında geçiş özelliği gösteren Afyonkarahisar, Osmanlı Dönemi’nde önemli bir sancak idari birimini oluşturmuş iken bu özelliğini Cumhuriyet Dönemi’nde de il idari birimi olarak devam ettirmiştir. Çalışma sahasının yüzölçümünün oldukça geniş ve dağlık bir topografyaya sahip olması, ildeki idari örgütlenmeyi de etkilemiştir. İl içerisinde etki sahaları dar idari birimler oluşturulurken, bazı yerleşmeler ulaşım etkisine bağlı olarak Afyonkarahisar il merkezi yerine, komşu illerin etki sahası içine girmektedir. Türkiye’nin mevcut idari bölünüş sistemine göre iller en büyük idari birimi oluşturmaktadır. Afyonkarahisar 14.016 km2 yüzölçümü ile ülkemizin 13. büyük ili olurken, 2020 yılı itibariyle sahip olduğu 736.912 kişilik nüfusu ile büyükşehir statüsü elde etme sınırında yer almaktadır. Diğer yandan il içerisinde mevcut durumda 18 ilçe idari ünitesi, 41 belde ve 422 köy idari ünitesi bulunmaktadır.The province of Afyonkarahisar, which is located in the Inner West Anatolia Section of the Aegean Region, is surrounded by provinces belonging to the Aegean, Mediterranean and Central Anatolia regions. Afyonkarahisar was an important sanjak settlement during the Ottoman Period, with the effect of its transitional geographical location between the Regions it has, while it continued this feature as a province in the Tanzimat Period and then as a provincial administrative unit in the Republic Period. The wide and mountainous topography of the working area has also affected the administrative organization in the province. While narrow administrative units are formed within the province, some settlements fall within the impact area of neighboring provinces instead of Afyonkarahisar city center due to the transportation effect. According to Turkey's current administrative division system constitutes the largest administrative unit the provinces. While Afyonkarahisar is the 13th largest city of our country with an area of 14,016 km2, it is on the border of achieving metropolitan status with its population of 736,912 as of 2020. On the other hand, there are 18 districts, 41 towns and 422 village settlements in the province

Influence of Tarhana Herb (Echinophora sibthorpiana) on Fermentation of Tarhana, Turkish Traditional Fermented Food

Tarhana herb (Echinophora sibthorpiana) (TH) is used as a spice in tarhana. It has a pleasant flavour and stimulates some microorganisms. In this study, the fermentation activity of tarhana was investigated by monitoring the lactic acid bacteria (LAB) and yeast populations when TH was used as additive. It can be said that tarhana herb (Echinophora sibthorpiana) prevented the decrease in the counts of LAB and yeast below the initial number during tarhana fermentation

Evaluation of genetic diversity of cultivated tea clones (Camellia sinensis (L.) Kuntze) in the eastern black sea coast by inter-simple sequence repeats (ISSRS)

SANDALLI, Cemal/0000-0002-1298-3687; PEHLIVAN, NECLA/0000-0002-2045-8380WOS: 000376744800008Tea is the most globally consumed drink after spring water and an important breeding plant with high economical value in Turkey. in half a century, various kinds of tea cultivars have been bred in Turkey to improve the quality and yield of tea plants. Since tea reproduces sexually, tea fields vary in quality. Thus, determining the genetic diversity and relationship of the plants to support breeding and cultivation is important. in this study we aimed to determine the genetic diversity of tea cultivars breeding in the Eastern Black Sea coast of Turkey and the genetic relationship between them, to verify whether the qualitative morphological designations of the clones are genetically true by the ISSR markers. Herein, the genetic diversity and relationships of 18 Turkish tea cultivars were determined using 15 ISSR markers with sizes ranging from 250 to 3000 base pairs. the similarity indices among these cultivars were between 0.456 and 0.743. Based on cluster analysis using UPGMA, some of tea cultivars originating from the same geographical position were found to be clustered closely. Our data provide valuable information and a useful basis to assist selection and cloning experiments of tea cultivars and also help farmers to find elite parental clones for tea breeding in the Eastern Black Sea coast of Turkey.Recep Tayyip Erdogan UniversityRecep Tayyip Erdogan University [BAP_2013.102.03.4]This work was supported by Recep Tayyip Erdogan University Research Fund Grants BAP_2013.102.03.4

Lornoxicam use to reduce the pain associated with propofol injection

Aim: To investigate the efficacy of lornoxicam in the prevention of the pain associated with propofol injection.Material and method: Approval for this study was granted by the ethics committee of our hospital. Using a computer randomisation software, 120 patients undergoing elective surgery were assigned to four equal groups. In Group I (control group), immediately before anaesthesia induction, 10 ml of isotonic 0.9% NaCl solution (placebo) was administered intravenously (IV). In Groups II, III and IV, the same injection contained 2 mg, 4 mg and 8 mg of lornoxicam respectively. A tourniquet was then applied to the forearm for two minutes. Pain evaluation was made using a verbal pain score.Results: Differences in pain severity scores were statistically significant between Groups I and II, Groups I and III, Groups I and IV and between Groups II and III (p < 0.05). However, no significant difference was determined between Groups III and IV (p = 0.401).Conclusion: In all groups administered with lornoxicam, there was a significant reduction in the severity of pain associated with propofol injection, in comparison with the control group. Maximum effect is obtained with a dose of 4 mg

Are serum delta neutrophil index and other inflammatory marker levels different in hyperemesis gravidarum

MakaleWOS:000911852000001PubMed ID : 36627732Hyperemesis gravidarum (HEG) is a condition characterized by nausea and vomiting, fluid electrolyte and acid–base imbalance, dehydration, weight loss, and ketonuria in early pregnancy. The relationship of HEG with inflammation has been studied in many studies. This study aimed to investigate the role of serum delta neutrophil index (DNI), a new inflammatory marker, and other inflammatory markers in demonstrating the disease’s presence and severity in HEG patients

Incidence and predictors of radial artery injury following transradial procedures: Yet another benefit of renin–angiotensin system blockade?

Background: Vasodilatory function of radial artery (RA) declines following the transradial catheterization. However, it is uncertain whether impaired vasodilatory function develops in every patient. The aim of this study was to investigate the incidence and predictive factors of impaired vasodilatory function following transradial procedures. Methods: Consecutive patients undergoing elective transradial procedures were prospectively enrolled. Ultrasound examination of RA was recorded just before and 1 week after the procedure. RA diameters and flow velocities were measured at baseline, after flow mediated vasodilation (FMD) and after nitrate mediated vasodilation (NMD). Results: Fifty-one patients were included (62 ± 11 years, 55% male, 41% hypertensive, 20% diabetic, 65% with coronary artery disease). Overall FMD and NMD were significantly impaired after 1 week. However, deterioration of FMD and NMD was observed in 67% and 71% of patients, respectively. Absolute change in FMD was significantly different in patients using a renin– angiotensin system (RAS) inhibitor compared to those who were not (1.9 ± 12.9 vs. –7.7 ± ± 12.7%, respectively, p = 0.025). Additionally, there was a moderate but significant correlation between baseline RA diameter and absolute change in NMD (r = 0.419, p < 0.001). RAS blockade was independently associated with protection against FMD deterioration (OR 0.241, 95% CI 0.066–0.883, p = 0.032), whereas RA diameter (OR 0.079, 95% CI 0.009–0.720, p = 0.024) and procedure time (OR 1.156, 95% CI 0.989–1.350, p = 0.068) were associated with NMD deterioration, although the latter had borderline significance. Conclusions: Vasodilatory function of RA gets impaired in most patients following transradial procedures. RAS blockade seems to exert a protective role against deteriorating endothelium- dependent vasodilation, whereas smaller RA diameter and potentially longer procedure time are associated with impaired endothelium-independent vasodilation.

THE EFFECT OF WEAR MECHANISM FOR PLASMA OXIDISED CP TI AND ITS ALLOYS ON TRIBOCORROSION PERFORMANCE

THE EFFECT OF WEAR MECHANISM FOR PLASMA OXIDISED CP TI AND ITS ALLOYS ON TRIBOCORROSION PERFORMANCEAbstract Commercially pure titanium (cp-Ti) and its alloys (Ti6Al4V, Ti45Nb, Ti6Al7Nb etc.) have an important use among biometallic materials. Recently developed alloying techniques and production methods have enabled many different titanium alloys to be used as biomaterials. Although harder and higher corrosion resistance than iron and its alloys, it is used as an invasive implant by applying various surface modifications to improve biodegradability performance. One of these processes is plasma oxidation process. With this process, corrosion resistance can be improved by obtaining more passive surfaces. There are many studies on these performance measurements in the literature. In this study, the effects of wear and corrosion mechanisms on the material in one cycle were investigated. Cp-Ti, Ti6Al4V and Ti45Nb were chosen as base materials. Samples were subjected to plasma oxidation for 600˚C-3 hours. Within the scope of this investigation, the adhesive wear mechanism on oxidized surfaces was compared with different types of abrasives, and its effect on corrosion performance was measured with the tribocorrosion test apparatus. Abrasion tests were carried out with two abrasive balls: tungsten carbide (WC) and silicon nitride (SiN) under 3 N load. Processes were carried out in two different media, dry and simulated body fluid (SBF). Potentiodynamic polarization scans were carried out using the scanning range of -0.28 V - 2 V in the presence of wear tests for tribocorrosion measurements. While abrasive wear mechanism is dominant in untreated samples, adhesive wear is at the forefront in coated samples. The effects that increase the corrosion resistance positively affected the performance of tribocorrosion. The high oxidation resistance of Ti and its alloys increased adhesive wear performance, and because of the higher corrosion resistance of Ti6Al4V and Ti45Nb, which were alloyed from these three material groups, their corrosion performance was higher than Cp-Ti.Keywords: Cp-Ti, Ti6Al4V, Ti45Nb, Plasma oxidation, Tribocorrosion