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Öğe Effect of different levels of royal jelly on biochemical parameters of swimmers(ACADEMIC JOURNALS, 2011) Saritas, Nazmi; Yildiz, Kadir; Buyukipekci, Serdar; Coskun, BetulThis study aims to investigate the effects of different levels of royal jelly supplementation on biochemical parameters in swimmers. Randomly selected 40 male swimmers aged 18 to 25 years attending the same trainings were recruited. Swimmers were assigned to 4 groups each with 10 subjects. Varying amounts of royal jelly (2, 1 g and 500 mg) were given to the 1st, 2nd and 3rd groups and placebo (corn starch) to the 4th group. Participants were trained by swimming totally 20 km in 2 h on 5 days a week for 4 weeks. Resting blood samples were taken before royal jelly administration and after 30 days of application. Then biochemical analyses were performed. Different levels of royal jelly were found to be ineffective on glucose, total cholesterol, high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, lactate dehydrogenase (LDH), creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT) levels of the swimmers. Blood urea nitrogen (BUN) and creatinine levels increased after the training program, and BUN level was higher in the group receiving 500 mg royal jelly than those in the other groups. The increment in creatinine levels was higher in those groups receiving higher amounts of royal jelly after the training. A supplementation of 500 mg, 1 and 2 g/day of royal jelly throughout the 30 day-exercise program was not significantly effective in the swimmers. Also, due to its high amino acid content, BUN and creatinine levels tended to increase.Öğe Increased fuel burn up in a CANDU thorium reactor using weapon grade plutonium(ELSEVIER SCIENCE SA, 2006) Sahin, Somer; Yildiz, Kadir; Sahin, Haci Mehmet; Sahin, Necmettin; Acir, AdemWeapon grade plutonium is used as a booster fissile fuel material in the form of mixed ThO2/PuO2 fuel in a Canada Deuterium Uranium (CANDU) fuel bundle in order to assure the initial criticality at startup. Two different fuel compositions have been used: (1) 97% thoria (ThO2) + 3PuO(2) and (2) 92% ThO2 + 5% UO2 + 3% PuO2. The latter is used to denaturize the new U-233 fuel with U-238. The temporal variation of the criticality k(infinity) and the burn-up values of the reactor have been calculated by full power operation for a period of 20 years. The criticality starts by k infinity = similar to 1.48 for both fuel compositions. A sharp decrease of the criticality has been observed in the first year as a consequence of rapid plutonium burnout. The criticality becomes quasi constant after the second year and remains above k infinity > 1.06 for similar to 20 years. After the second year, the CANDU reactor begins to operate practically as a thorium burner. Very high burn up could be achieved with the same fuel material (up to 500,000 (MWD)-D-./T), provided that the fuel rod claddings would be replaced periodically (after every 50,000 or 100,000 MW.D/T). The reactor criticality will be sufficient until a great fraction of the thorium fuel is burnt up. This would reduce fuel fabrication costs and nuclear waste mass for final disposal per unit energy drastically. (c) 2006 Elsevier B.V. All rights reserved.Öğe Investigation of effectiveness of different tritium breeding materials in a fusion-fission hybrid reactor fuelled with ThSi 2-moderated with natural Li(2005) Yildiz, Kadir; Acir, AdemIn this work, a fusion-fission reactor fuelling with ThSi 2 is investigated. Natural Li is selected as a moderator in the reactor and Li 2TiO 3, Li 2ZrO 3, Li 4SiO 4 and Li 2O are used in the tritium breeding zones of the reactor. 14.1 MeV D-T neutrons are used as a fusion neutron source. Tritium breeding rates, U breeding rates, fission energy breeding rates and fission power production are investigated for ?t=10 days during a reactor operation period over four years. Using Li 2O in tritium breeding zones of the reactor provided highest tritium breeding rate. Highest value of 233U breeding and production of the fission energy are reached with using of Li 2ZrO 3 in tritium breeding zones of the blanket.Öğe Neutronic performance of CANDU reactor fuelling with ThC2/(UC2)-U-233(WILEY-BLACKWELL, 2011) Yildiz, Kadir; Sahin, Necmettin; Alkan, MahmutU-233 isotope is used as a booster fissile fuel material in the form of mixed ThC2/(UC2)-U-233 fuel in a Canada Deuterium Uranium (CANDU) fuel bundle in order to assure the initial criticality at startup. Three different fuel compositions have been used: (1) 97% ThC2+3% (UC2)-U-233, (2) 98% ThC2+2% (UC2)-U-233 and (3) 99% ThC2+1% (UC2)-U-233. The temporal variation of the criticality k(infinity) and the burn-up values of the reactor have been calculated by full-power operation for a period of 20 years. The criticality starts by k(infinity) = 1.541, 1.355 and 0.995 for modes of (1), (2) and (3) fuel compositions, respectively. A sharp decrease in the criticality has been observed in the first 2 years as a consequence of rapid U-233 burnout fuelling with (1) and (2) modes. The criticality becomes quasi-constant after the second year and remains above k(infinity) similar to 1.06 for 20 years. After the second year, the CANDU reactor begins to operate practically as a thorium burner. Very high burnup could be achieved with the same fuel materials (up to 500 000 MW day t (1)), provided that the fuel rod claddings would be replaced periodically (after every 500 00 or 100 000 MW day t(-1)). The reactor criticality will be sufficient for fuelling with (1) and (2) modes until a great fraction of the thorium fuel is burnt up. This would reduce fuel fabrication costs and nuclear waste mass for final disposal per unit energy drastically. Copyright (C) 2010 John Wiley & Sons, Ltd.Öğe The effects of neutron energy-group structures and resonance treatment on integral parameters in a fusion breeder blanket fuelling with ThO2(2005) Şahin, Sümer; Şahin, H. Mehmet; Yildiz, Kadir; Acir, AdemThe purpose of this work is to investigate the effects of neutron energy-group structures and resonance treatments on the main integral neutronic parameters in a fusion-fission hybrid reactor, which has a fast and a thermal blanket fuelling with ThO2. As a neutron source, D-T fusion neutrons (14.1 MeV) are used and fissile zone is cooled (a) with light water for the moderated blanket and (b) with pressurized helium gas for the fast blanket. The neutronic parameters have been evaluated with and without a resonance treatment for the same blanket compositions for the sake of a consistent comparison. Neutron energy-group structures in the neutron libraries and description of fusion neutron source spectrum mainly affect the neutron reactions above a threshold energy in fast neutron groups such as 7Li(n, ?n?)T and 232Th(n,f). These reactions are not affected to resonance treatment. Neutron reactions in the resonance and thermal energy groups are sensitive to resonance treatment, such as 6Li(n,?)T and 232Th(n,?), depending on the resonance structures.Öğe The Effects of the Different Tritium Breeding Materials to Fusil and Fisil Fuel Breeding in a ThSi2 Fuelled- Flibe Moderated Fusion-Fission Hybrid Reactor(Gazi Univ, 2007) Acir, Adem; Yildiz, Kadir; Alkan, Mahmut; Sahin, NecmettinIn this work, in a ThSi2 fuelled-flibe moderated fusion-fission reactor in the tritium breeding zones of the reactor are used four different Li compound, respectively, Li2TiO3, Li2ZrO3, Li4SiO4 and Li2O. D-T fusion reactions are used as a fusion neutron source which produces 14.1 MeV neutrons with averaged energy. Fusil and fissile fuel breeding rates, fission energy breeding rates and fission power production are investigated for Delta t=10 days during a reactor operation period in four years. In tritium breeding zones used Li2O of the reactor provided highest fusil breeding rate whereas, highest value of fissile breeding and production of the fission energy are reached with using of Li2TiO3 and Li2ZrO3 in tritium breeding zones of the blanket.Öğe The perceived effect of digital transformation and resultant empowerment on job performance of employees in the fitness family business(Emerald Group Publishing Ltd, 2024) Yildiz, Kadir; Akoglu, Halil Erdem; Emir, Esra; Angosto, Salvador; Garcia-Fernandez, JeronimoPurposeThe impact of technological transformations in all sectors is undeniably significant, especially in fitness family business. The aim is to examine the digital transformation perceptions of fitness centre employees and the effects of perceived empowerment on their job performance in family business in Turkey.Design/methodology/approachThe sample was 334 fitness centre employees. Four variables were evaluated (digital transformation, meaning competence, self-determination and job performance), and PLS-SEM was used.FindingsThe digital transformation process in the fitness sector can be considered as an important factor in terms of creating new business ventures. Our results showed that digital transformation perceived by family business employees had a significantly influence on the meaning competence of the employees. Also, the meaning competence of employees was a mediator between the digital transformation and job performance.Practical implicationsManagers of family businesses must take into account that an appropriate digital transformation of their products and/or services has an impact on the meaning competence of their employees. Thus, through increased competence in employee performance, the digitization of family business fitness will lead to higher employee performance and productivity.Originality/valueThis study innovates by linking digital transformation as a factor influencing the coach's own motivation and self-perceived competence in the use of technology to their job performance.Öğe Uniform nuclear heat density in the CANDU fuel bundle(2004) Şahin, Sümer; Yildiz, Kadir; Acir, Adem[No abstract available]Öğe Why do athletes consume luxury brands? A study on motivations and values from the lens of theory of prestige consumption(Emerald Group Publishing Ltd, 2024) Akoglu, Halil Erdem; Yildiz, Kadir; Kumar, SushantPurposeAlthough extant literature exists on luxury consumption, limited studies have focused on motivation and values to consume luxury brands among athletes. The study aims to uncover the motivations that guide athletes' decision-making processes to consume luxury brands.Design/methodology/approachThe study utilized the theory of prestige consumption to develop a model. The model posits that bandwagon, snob and veblen motivations guide athletes to seek social and conspicuous values in their consumption of luxury brands. A survey-based questionnaire approach was used to collect data from 343 athletes from Turkey by considering brands from different product categories.FindingsFindings indicated that bandwagon and veblen motivations are associated with social and conspicuous values. The findings also suggested that bandwagon, snob and veblen motivation are positively associated with luxury consumption intentions. Also, the social and conspicuous values of athletes determine their intentions to consume luxury. The mediating effects of social and conspicuous values are also confirmed.Originality/valueThe study's findings are first to empirically examine the influence of motivations on social and conspicuous value among athletes. The results show that the luxury consumption motivations of the athletes have a strong role in their intention to purchase luxury products. The findings also offer novel managerial implications.
