Analysing fluid-structure interaction with CFD and FEA on a marine double-wall LNG piping system

In this study, the interaction of fluid-structure with Ansys Fluent and Structural was analysed on a double-wall LNG piping system in a marine ship. In terms of simulations, the inner tube of the double-walled tube on the TSR-18008 ship designed by SU Ar-Ge Dizayn ve Mühendislik A.Ş. is considered. Two different simulations were made; the first analysis was a computational fluid dynamics analysis and the results obtained from this were imported into the finite element analysis also known as structural analysis and the structural analysis was undertaken together using these data. The mesh used in the simulations has 2,985,116 elements and 2,135,093 nodes. The inlet velocity of the gas is 6.5 m/s and the temperature value is 108 K as boundary conditions. Seventeen cylindrical support elements are used to ensure the strength of the Liquefied Natural Gas pipe system. Three different pipe materials, which are structural steel, stainless steel, and aluminium alloy, have been considered for the numerical structural analysis. The highest stresses were observed at the elbows and results were given using various contours including stresses, strains, temperatures and streamlines in these elbows

Formation of carbide derived carbon coatings on SiC

Control over the structure of materials on nanoscale can open numerous opportunities for the development of materials with controlled properties. Carbon, which is one of the most promising materials for nanotechnology, can be produced by many different methods. One of the most versatile, in terms of a variety of structures demonstrated (graphite, porous amorphous carbon, nanotubes, graphene and diamond), is selective etching of SiC and other carbides. Since the Si atoms are extracted layer by layer, atomic level control of the carbon structures can potentially be achieved without changing the size and shape of the sample. Carbon produced by this method is called Carbide-Derived Carbon (CDC).In this work, CDC formation was studied on single crystalline 3C-SiC whiskers and 6H-SiC wafers by chlorination and vacuum decomposition at high temperatures with the goals to better understand the mechanism of carbide-to-carbon transformation and determine conditions for synthesis of desired carbon structures. The reaction kinetics, morphology and shape conservation were investigated at nanoscale. The transformation mechanism of the SiC surface to carbon was discussed in detail accounting to the effects of processing parameters (temperature, and composition of the environment), and material parameters (surface conditions, surface chemistry, crystal face, etc.). The characterization of the carbon structures was performed by using scanning electron microscopy (SEM), Raman spectroscopy and transmission electron microscopy (TEM).We compared chlorination of SiC whiskers with wet etching and showed that chlorination revealed the dislocations, while wet etching resulted in pagoda-like 3-D nanostructures upon selective etching of stacking faults (SFs). The difference in etching mechanisms was discussed.We determined the processing conditions for controlled synthesis of carbon structures like graphene, graphite and carbon nanotubes (CNTs) on the surface of α-SiC wafers by decomposition in low vacuum. CNT brushes grown on SiC showed good mechanical properties and high oxidation resistance. Moreover, we showed that patterns of graphite and catalyst-free nanotubes can be grown simultaneously and directly on a semiconductor SiC wafer. Devices built in this way can be used in applications from sensing to field emission.Ph.D., Materials Science and Engineering -- Drexel University, 200

Viscoelasticity and high buckling stress of dense carbon nanotube brushes

We report on the mechanical behavior of a dense brush of small-diameter (1–3 nm) non-catalytic multiwall (2–4 walls) carbon nanotubes (CNTs), with ~10 times higher density than CNT brushes produced by other methods. Under compression with spherical indenters of different radii, these highly dense CNT brushes exhibit a higher modulus (~17–20 GPa) and orders of magnitude higher resistance to buckling than vapor phase deposited CNT brushes or carbon walls. We also demonstrate the viscoelastic behavior, caused by the increased influence of the van der Waals’ forces in these highly dense CNT brushes, showing their promise for energy-absorbing coatings

New constraints on micro-seismicity and stress state in the western part of the North Anatolian Fault Zone : Observations from a dense seismic array

Major funding was provided by the UK Natural Environment Research Council (NERC) under grant NE/I028017/1 and partially supported by Boğaziçi University Research Fund (BAP) under grant 6922. We would like to thank all the project members from the University of Leeds, Boğaziçi University, Kandilli Observatory, Aberdeen University and Sakarya University. I would also like to thank Prof. Ali Pinar and Dr. Kıvanç Kekovalı for their valuable comments. Some of the figures were generated by GMT software (Wessel and Smith, 1995).Peer reviewedPostprin

Overcoming the Interfacial Limitations Imposed by the Solid–Solid Interface in Solid‐State Batteries Using Ionic Liquid‐Based Interlayers

Li-garnets are promising inorganic ceramic solid electrolytes for lithium metal batteries, showing good electrochemical stability with Li anode. However, their brittle and stiff nature restricts their intimate contact with both the electrodes, hence presenting high interfacial resistance to the ionic mobility. To address this issue, a strategy employing ionic liquid electrolyte (ILE) thin interlayers at the electrodes/electrolyte interfaces is adopted, which helps overcome the barrier for ion transport. The chemically stable ILE improves the electrodes-solid electrolyte contact, significantly reducing the interfacial resistance at both the positive and negative electrodes interfaces. This results in the more homogeneous deposition of metallic lithium at the negative electrode, suppressing the dendrite growth across the solid electrolyte even at high current densities of 0.3 mA cm$^{-2}$. Further, the improved interface Li/electrolyte interface results in decreasing the overpotential of symmetric Li/Li cells from 1.35 to 0.35 V. The ILE modified Li/LLZO/LFP cells stacked either in monopolar or bipolar configurations show excellent electrochemical performance. In particular, the bipolar cell operates at a high voltage (≈8V) and delivers specific capacity as high as 145 mAh g$^{-1}$ with a coulombic efficiency greater than 99%

Performance study of magnesium-sulfur battery using a graphene based sulfur composite cathode electrode and a non-nucleophilic Mg electrolyte

Here we report for the first time the development of a Mg rechargeable battery using a graphene–sulfur nanocomposite as the cathode, a Mg–carbon composite as the anode and a non-nucleophilic Mg based complex in tetraglyme solvent as the electrolyte. The graphene–sulfur nanocomposites are prepared through a new pathway by the combination of thermal and chemical precipitation methods. The Mg/S cell delivers a higher reversible capacity (448 mA h g−1), a longer cyclability (236 mA h g−1 at the end of the 50th cycle) and a better rate capability than previously described cells. The dissolution of Mg polysulfides to the anode side was studied by X-ray photoelectron spectroscopy. The use of a graphene–sulfur composite cathode electrode, with the properties of a high surface area, a porous morphology, a very good electronic conductivity and the presence of oxygen functional groups, along with a non-nucleophilic Mg electrolyte gives an improved battery performance

The effect of teff seed on hematological findings and anthropometric measurements

Background: The low incidence of diseases such as celiac, anemia, osteoporosis, and obesity in Ethiopia has aroused interest in the study of teff. The primary objective of this study was to determine the effect of regular consumption of teff seeds on hematological findings and anthropometric measurements in overweight and obese individuals. The secondary objective was to compare these effects of teff seeds with the Mediterranean diet. Methods: In our study, planned as a cohort study, 28 participants followed the teff seed-containing diet (n=14) and the Mediterranean diet (n=14) for 3 months. To determine nutritional status, a 72-h recall was taken. Anthropometric measurements and hematological findings were recorded at the beginning and end of the study. Results: There was a significant decrease in fasting blood glucose, cholesterol, LDL, and HDL levels in the teff group (p<0.05). The increase in total protein levels in the teff group was significantly higher than in the Mediterranean diet group (p=0.05). With increased intake of carbohydrates (g) in the teff group, fasting blood glucose levels decreased significantly. There was no significant difference between the two groups regarding anthropometric measurements. Conclusion: It has been found that the teff seed has no predominance over anthropometric measurements, as compared to the Mediterranean diet, and that it is more effective in improving hematological findings related to obesity. There is a need for more comprehensive studies that also address physical activity, the different types of teff seeds available, and include increased participant numbers.Institute of Health Mega Research Project of Jamma Universit

Observing of loosing weight of mothers in first year after parturitionAnnelerin, doğum sonu ilk yılda kilo verme durumlarının incelenmesi

Gained weight during pregnancy which have not been loosed following parturition or growing fat after parturition, effect the life of women on physiological, psychological and social aspects. It is aimed to observe loosing weight that were gained during pregnancy, in first year after parturition in this study.This is a croos –sectional type research. Sampling of the research is composed from mothers who were given birth one year ago and has accepted to attend this research who were admitted to three different family health centers between January 2014 - March 2015 that were randomly determined in Center of Manisa Provence (n=232).  Data collecting form of the research  is generated by the researchers in the direction of related literature.  Number, percentage, mean values and the chi-square test were used for analyzing of data.Average age of mothers is 27.8±5.3 and average number of parturiton is 2.0±1.1. Average gained weight during pregnancy is determined as 12.4±4.5 kg.  BMI (Body mass index) of mothers is 25.99±3.85 and 48.3 % of them are overweight according to BMI. It’s determined that while 16.8 % of mothers loosed the weight that was gained during pregnancy, the others couldn’t loose that weight or gained more weight according to the research for situation of loosing weight  in first year after parturation. A meaningful relationship is not found between loosing weight after parturation and age of mothers, education levels, number of liveborns, number of living children, delivery method, nursing, routine daily houseworks, total fluid intake, gaining weight during pregnancy (p&gt;0.05). A statistically meaningful relationship is found between  loosing weight after parturation and doing exercise or fitness, average sleeping time, BMI before pregnancy. (p&lt;0.05).It’s determined that most of the mothers couldn’t loose weight which were gained during pregnancy or gained more weight at first year after parturation. Also it’s determined that  sleeping adequately and regular physical exercises have positive effect on loosing weight after parturation.   ÖzetGebelikte alınan kiloların doğum sonu dönemde verilememesi ya da doğum sonu alınan kilolar kadın yaşamını fizyolojik, psikolojik ve sosyal yönden etkilemektedir. Bu çalışma, kadınların gebelik süresince aldığı kiloları doğum sonu ilk bir yılda verme durumlarını incelemek amacıyla yapılmıştır.Araştırma kesitsel tiptedir. Araştırmanın örneklemini Manisa ili kent merkezinde bulunan ve rastgele belirlenmiş üç Aile Sağlığı Merkezine Ocak 2014 – Mart 2015 tarihleri arasında başvuran ve araştırmaya katılmaya kabul eden, bir yıl önce doğum yapmış anneler oluşturmuştur (n=232). Araştırmada veri toplama formu, ilgili literatür doğrultusunda araştırmacılar tarafından oluşturulmuştur. Verilerin analizinde sayı, yüzde, ortalama değerleri ve ki-kare testi kullanılmıştır.Annelerin yaş ortalaması 27.8±5.3 olup doğum sayısı ortalaması 2,0±1,1’dir. Annelerin gebelik boyunca aldıkları kiloların ortalaması 12.4±4.5 kg bulunmuştur. Annelerin doğumdan bir yıl sonraki ortalama beden kitle indeksleri (BKI) 25.99±3.85 olup %48.3’ü BKI’ye göre fazla kiloludur. Gebelik süresince alınan kiloların doğum sonu ilk yılda verilme durumu incelendiğinde, annelerin %16.8’sinin gebelikte aldığı kiloları verdiği, diğer gebelerin ise gebelikte aldığı kiloları vermediği ya da kilo aldığı saptanmıştır. Annelerin yaş, eğitim, canlı doğum sayısı, yaşayan çocuk sayısı, doğum şekli, emzirme, günlük ev işlerini yapma, sıvı alımı, gebelikte kilo alımı ile doğumdan sonra kiloların verilme durumu arasında anlamlı bir ilişki bulunmamıştır (p&gt;0.05). Annelerin egzersiz/ spor yapma durumu, ortalama uyku süresi, gebelik öncesi BKI ile doğum sonu dönemde kilo verme arasında istatistiksel olarak anlamlı ilişki saptanmıştır. (p&lt;0.05).Annelerin çoğunun, gebelik döneminde aldığı kiloları doğumdan sonraki ilk bir yılda vermediği ya da kilo aldığı; doğum sonu dönemde yeterli uyumanın ve düzenli egzersizlerin kilo vermeyi pozitif yönde etkilediği belirlenmiştir.