Optimization of Conical Micro-Diffusers and Micro-Nozzles Considering Entropy Generation

Fluid flow characteristics and entropy generation in a circular diffuser/nozzle element are studied numerically. The flow is assumed to be isothermal, laminar and incompressible with constant thermo-physical properties. The velocity field, mass flow rate, and entropy generation are investigated for several half angles in combination with several values of pressure drops. The effect of diffuser half angle on the entropy generation is investigated and discussed. Furthermore, the effect of the half angle of diffuser on the diffuser efficiency and the effect on the rectification efficiency are explained. It is shown that there is an optimum operation half angle for which the diffuser efficiency has a maximum value. In the case of a micro-diffuser 1 mm long with an inlet diameter of 100 μm, the optimum half angle was found to be 2.5°. These results are based on several parametric simulations ranging from 0 to 7° half angles and covering pressure drops between 500 and 2000 Pa.King Fahd University of Petroleum and Minerals (Deanship of Scientific Research

Changes in some physico-chemical content of Anatolian buffalo milk according to the some environmental factors

The aim of this study was to determine the some physico-chemical content of raw milk from Anatolian water buffaloes raised under different village conditions in the Tokat province of Northern Turkey. The study materials included 1272 milk samples from 149 water buffaloes raised at 12 separate villages of the Erbaa, Turhal, and Pazar counties in the Tokat Province. Milk samples were collected during the morning milking between the months of February and May 2012 to 2014. The density, freezing point degree, dry matter, nonfat dry matter (or solid non fat), fat, protein, lactose, milk urea nitrogen and casein content of the milk samples were determined. The study results demonstrated that the mean dry matter, nonfat dry matter, fat, protein, lactose, casein content, density, milk urea nitrogen (MUN) and freezing point degree (FPD) of the raw milk samples were 16.99±0.108%, 10.88±0.036%, 5.98±0.107%, 4.85±0.043%, 5.17±0.021%, 3.61±0.036%, 1029±0.056, 21, 22 mg/dl and 0.55°C, respectively. The study data were evaluated according to the water buffaloes’ lactation stage, parity, and season by using the SPSS statistical program. It was concluded that the sampling time, parity, village conditions, stage of lactation and calving age had a significant effect (P<0.05) on the density, freezing point degree, dry matter, nonfat dry matter, fat, protein, lactose, and casein content of raw milk from the Anatolian water buffalo. © 2016, Kasetsart University. All rights reserved.TAGEM/60MANDA2011-01 --This investigation was supported by Republic of Turkey Ministry of Food, Agriculture and Livestock, General Directorate of Agricultural Research and Policies for financial support (TAGEM/60MANDA2011-01). -

Highly Permeable Perfluorinated Sulfonic Acid Ionomers for Improved Electrochemical Devices: Insights into Structure-Property Relationships.

Rapid improvements in polymer-electrolyte fuel-cell (PEFC) performance have been driven by the development of commercially available ion-conducting polymers (ionomers) that are employed as membranes and catalyst binders in membrane-electrode assemblies. Commercially available ionomers are based on a perfluorinated chemistry comprised of a polytetrafluoroethylene (PTFE) matrix that imparts low gas permeability and high mechanical strength but introduces significant mass-transport losses in the electrodes. These transport losses currently limit PEFC performance, especially for low Pt loadings. In this study, we present a novel ionomer incorporating a glassy amorphous matrix based on a perfluoro(2-methylene-4-methyl-1,3-dioxolane) (PFMMD) backbone. The novel backbone chemistry induces structural changes in the ionomer, restricting ionomer domain swelling under hydration while disrupting matrix crystallinity. These structural changes slightly reduce proton conductivity while significantly improving gas permeability. The performance implications of this trade-off are assessed, which reveal the potential for substantial performance improvement by incorporation of highly permeable ionomers as the functional catalyst binder. These results underscore the significance of tailoring material chemistry to specific device requirements, where ionomer chemistry should be rationally designed to match the local transport requirements of the device architecture

Safety and efficacy of vanzacaftor-tezacaftor-deutivacaftor in adults with cystic fibrosis: Randomised, double-blind, controlled, phase 2 trials

BACKGROUND: Elexacaftor-tezacaftor-ivacaftor has been shown to be safe and efficacious in people with cystic fibrosis and at least one F508del allele. Our aim was to identify a novel cystic fibrosis transmembrane conductance regulator (CFTR) modulator combination capable of further increasing CFTR-mediated chloride transport, with the potential for once-daily dosing. METHODS: We conducted two phase 2 clinical trials to assess the safety and efficacy of a once-daily combination of vanzacaftor-tezacaftor-deutivacaftor in participants with cystic fibrosis who were aged 18 years or older. A phase 2 randomised, double-blind, active-controlled study (VX18-561-101; April 17, 2019, to Aug 20, 2020) was carried out to compare deutivacaftor monotherapy with ivacaftor monotherapy in participants with CFTR gating mutations, following a 4-week ivacaftor monotherapy run-in period. Participants were randomly assigned to receive either ivacaftor 150 mg every 12 h, deutivacaftor 25 mg once daily, deutivacaftor 50 mg once daily, deutivacaftor 150 mg once daily, or deutivacaftor 250 mg once daily in a 1:1:2:2:2 ratio. The primary endpoint was absolute change in ppFEV FINDINGS: In study VX18-561-101, participants treated with deutivacaftor 150 mg once daily (n=23) or deutivacaftor 250 mg once daily (n=24) had mean absolute changes in ppFEV INTERPRETATION: Once-daily dosing with vanzacaftor-tezacaftor-deutivacaftor was safe and well tolerated and improved lung function, respiratory symptoms, and CFTR function. These results support the continued investigation of vanzacaftor-tezacaftor-deutivacaftor in phase 3 clinical trials compared with elexacaftor-tezacaftor-ivacaftor. FUNDING: Vertex Pharmaceuticals

Overcoming barriers to a successful transition from pediatric to adult care

As life expectancy for people with cystic fibrosis (CF) has increased dramatically, so has the need for a guided, structured transition from pediatric to adult-focused care. A formalized transition program allows for seamless transfer of patients between providers, helping to ensure continuity of care, and avoid potential declines associated with inconsistent medical care. New CF Center guidelines issued by the CFF strongly recommend that each center establish a transition program for age-appropriate transition to an adult CF clinic. In this article, we explore the remaining barriers to establishing a transition program in a CF Center and offer examples of several successful models. We describe CFF-sponsored and other initiatives that exist to support centers in establishing a transition program and discuss the need for ongoing research in this area

An evaluation of the MA TEFL program at Bilkent University

Ankara : The Institute of Economic and Social Sciences of Bilkent University, 1996.Thesis (Master's) -- Bilkent University, 1996.Includes bibliographical references leaves 90-91This study aimed to investigate the achievements of the M.A. TEFL program at Bilkent University in terms of its goals and objectives, as well as determine possible changes for the future of the program. The data were collected through document analysis, interviews and questionnaires. Document analysis and interviews were conducted to collect data about the original goals and objectives of the program, as well as to determine criteria for assessing the success of the program. In questionnaires and telephone-interviews, two groups: the graduates of the program and their administrators, were asked their opinions about the characteristics of the program and the personal and professional effects of the program on program participants. The results of both the questionnaires and telephone interviews, based on the graduates' and their administrators' responses, indicate that overall the M.A. TEFL program at Bilkent University has achieved its goals and objectives in terms of improving its participants' personal and professional lives as language teachers. The results also show that the program has had the intended effect in Turkey, that the participants have improved their teaching methodologies, and critical thinking, and they have also become more aware of their students' needs as a results of participating in the program. Administrators' ratings about the characteristics and the effects of the program were consistently less than the graduates of the program. However, both groups agreed that there was a continued need for such a program in Turkey, though again the administrators were less enthusiastic than the graduates. However, results also showed that the graduates have not increased in their professional responsibilities or positions, suggesting either that having an M.A. in TEFL is not enough for an increase in responsibilities, or that one to seven years of experience with an M.A. degree is not enough to be promoted to a higher position. Results also suggest that some changes should be made in the design and curriculum of the program, such as increasing teacher development opportunities and selecting more appropriate instructors for the program.Kanatlar, Ahmet ZM.S

Psychology of loneliness of high school students

AbstractThis study purposes to determine relation between the level of loneliness of the students who have been attended at four state high schools and the various variables such as school, sex, accommodation types and academic achievement. The sample of study is assigned through random sampling. For this, the sample of this study was composed with a hundred thirty-one female and one hundred thirty-six male students from four high schools in Erzurum. The sixty-five students from a high school, the seventy-two students from B high school, sixty students from C high school, sixty-eight students from D high school are randomly determined. Besides, the students who are written the composition with emotion of loneliness are sixty students at total. Thus, three hundred and twenty-five students compose the sample that accepted to attend. In this study, UCLA loneliness scale (University of California Los Angeles Loneliness Scale) and a short information form prepared by the researchers are used as data collection tool. The information relating school, sex, accommodation types and the average of period is wanted from the students at the form of information. The data obtained from loneliness scale (UCLA) is analyzed by using SPSS considering above variables. The compositions written by students are qualitatively evaluated by the researchers. According to finding of this study, a significant relation is found between the loneliness and sex at 0.05 significant levels. The levels of loneliness of girls are too many from the man (XF=22.27 and XM=20.88). Between accommodation types with the emotion of loneliness of the high school is found not to be significant relation. Furthermore, between the academic achievements with the emotion of loneliness of the high school is determined not to be an expressive relation

The use of public spaces in urban development

Son 30 yıldır d&uuml;nya devletlerinin g&uuml;ndemlerinde &ldquo;s&uuml;rd&uuml;r&uuml;lebilir toplumsal gelişme&rdquo; s&ouml;ylemi yer almaktadır. Bu paralelde, d&uuml;nya kentlerinin ortak dertlerinin &ccedil;&ouml;z&uuml;m&uuml; de &ldquo;s&uuml;rd&uuml;r&uuml;lebilir kentsel d&ouml;n&uuml;ş&uuml;m&rdquo; olarak belirlenmektedir. Makalede bir kentsel alanın geliştirilmesi ya da yeniden yapılandırılması konusunda d&ouml;n&uuml;ş&uuml;m i&ccedil;in &ldquo;Kentsel Kamusal Alanların&rdquo; planlama aracı olarak sağlayabileceği fırsatların &ouml;nemini ortaya koymak ama&ccedil;lanmaktadır. &ldquo;Kentsel kamusal alan&rdquo; kavramı devlet m&uuml;lkiyeti ile bağlantılı olmaktan &ccedil;ok, &ldquo;kamusal alan&rdquo; ile bağlantılı olarak geliştirilmekte ve &ldquo;halkın yararlanması, denetimi ve d&ouml;n&uuml;şt&uuml;rmesine&rdquo; konu olan alanlar olarak değerlendirilmektedir. &ldquo;Kamusal alanların&rdquo; kentsel geliştirme i&ccedil;in gereken katalizat&ouml;r ortamın ve kritik ivmeyi sağlayacak cazibe kullanımlarının geliştirilmesi i&ccedil;in kullanılması &ouml;ng&ouml;r&uuml;lmekte ve bunun kavramları geliştirilmektedir. &nbsp;Anahtar Kelimeler: Kamusal alan, kentsel geliştirme, kentsel tasarım, mekansal d&ouml;n&uuml;ş&uuml;m, s&uuml;rd&uuml;r&uuml;lebilir kentsel d&ouml;n&uuml;ş&uuml;m.?Sustainable social development? has been on the agenda of nations for the last 30 years. In parallel with this, ?sustainable urban transformation? has been designated as the solution to the common problems of our planet?s cities. The planning and project development approach summarized in the article aims to emphasize the importance of the opportunities presented by ?Urban Public Spaces? as instruments of transformation planning in the development or restructuring of urban spaces. We anticipate the promotion of and develop the conceptual framework for the use of ?urban spaces? as centers of attraction providing the necessary catalytic environment and critical mass for urban development. The development of the conceptual scope and physical boundaries of ?urban spaces? discussed in this article is important more as an alternative approach than as a means of reorganizing ownership patterns. The essence of this approach is not about ?ownership?; it is rather about that which is ?social?, about ?social value? which upholds social benefits above individual gains, about ?socialization of urban life?, and about ?urban consciousness?. It is related to the spatial formations of human coexistence with the ?other? which shape our cultural mosaic. Keywords: Public space, spatial transformation, sustainable urban transformation, urban design, urban development

Economical Feasibility of Utilizing Photovoltaics for Water Pumping in Saudi Arabia

Energy and water are the two major need of the globe which need to be addressed for the sustenance of the human beings on this planet. All the nations, no matter most populous, developed and developing need to diversify the means and ways of producing energy and at the same time guarding the environment. This study aims at techno economical feasibility of producing energy using PV solar panels and utilizing it to pump-water at Dhahran, Riyadh, Jeddah, Guriat, and Nejran regions in Saudi Arabia. The solar radiation data from these stations was used to generate electricity using PV panels of 9.99 kW total capacity. Nejran region was found to be most economical in terms of minimal payback period and cost of energy and maximum internal rate of return whereas PV power production was concerned. Water-pumping capacity of the solar PV energy system was calculated at five locations based on the PV power production and Goulds model 45J series of pumps. Monthly total and annual total water pumping capacities were determined. Considering the capital cost of combined solar PV energy system and the pump unit a cost analysis of water pumping for a well of 50 m total dynamic head (TDH) was carried out. The cost of water pumping was found to vary between 2 and 3 /m3

Water Uptake in PEMFC Catalyst Layers

Water uptake profiles of proton-exchange-membrane fuel-cell catalyst layers are characterized in the form of capillary-pressure saturation (Pc-S) curves. The curves indicate that the catalyst layers tested are highly hydrophilic and require capillary pressures as low as -80 kPa to eject imbibed water. Comparison of materials made with and without Pt indicates a difference in water ejection and uptake phenomena due to the presence of Pt. The addition of Pt increases the tendency of the catalyst layer to retain water. Dynamic vapor sorption (DVS) is used to characterize the water-vapor sorption onto Nafion, Pt/C, and C surfaces. The DVS results align with the trends found from the Pc-S curves and show an increased propensity for water uptake in the presence of Pt. The effect of the ion in Nafion, sodium or protonated form, is also compared and demonstrates that although the protonation of the Nafion in the catalyst layer also increases hydrophilicity, the effect is not as great as that caused by Pt