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排序方式: 共有168条查询结果,搜索用时 250 毫秒
31.
O. Erdinc O. ElmaM. Uzunoglu U.S. SelamogullariB. Vural E. UgurA.R. Boynuegri S. Dusmez 《International Journal of Hydrogen Energy》2012
Lately, interest in renewable sources, especially wind and solar energy, has shown a significant increase in all over the world that mostly depends on climate-threatening conventional fossil fuels. Besides, hybrid use of these power sources with suitable back-up units provides many advantages compared to sole use of these sources. In this regard, a hybrid system consisting of a wind turbine for utilizing the wind energy, photovoltaic panels for solar energy, fuel cell for providing back-up power and a battery unit for storing the possible excess energy production and supplying the transient load is considered in this study. Experimental assessment of this system in different case studies including the real time measured dynamic power demand of an office block is realized. The collaborative actions of the proposed hybrid system with a fuzzy logic based energy management strategy during fluctuations of renewable-based power production are investigated. Thus, results of this study may be valuable for evaluating the feasibility of stand-alone hybrid renewable energy units for future power systems. 相似文献
32.
Kubra Oz Mustafa Yavuz Hasim Yilmaz Halil Ibrahim Unal Bekir Sari 《Journal of Materials Science》2008,43(4):1451-1459
In this study, electrorheological (ER) properties of polyindole (PIN) and polyindole/poly (vinyl acetate), (PIN/PVAc) conducting
composites having different compositions were investigated. Conductivities and dielectric properties of these composites were
determined. The particle sizes of the composites were determined by dynamic light scattering method. Suspensions of PIN and
PIN/PVAc composites were prepared in silicone oil, at several concentrations (c = 5–25%, m/m) and their sedimentation stabilities were determined. Then the effects of dispersed particle concentration,
shear rate, electric field strength, frequency, and temperature onto ER activities of suspensions were investigated. The flow
times of these suspensions at various dc electric field strengths were measured. Further, creep tests were applied to the
composite suspensions and a reversible viscoelastic deformation was observed. 相似文献
33.
Growth of Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus bovis, and Streptococcus uberis was studied in normal milk, simulated bulk tank milk, and aseptic mastitic milk held at simulated fluctuating temperatures of farm bulk tank for 48 h. With the exception of S. bovis, growth rates of the other five bacteria were similar in both normal and simulated bulk tank milk. Mastitic milk inhibited growth of all bacteria studied. A 24-h adjustment period occurred before most of the bacteria started growing. The mastitis level in a dairy herd may be monitored by cultures of bulk tank milk samples and by calculations as discussed in this study. 相似文献
34.
Paulo Rema Irineu Batista Pedro Pousão‐Ferreira Luisa M. P. Valente Sónia M. G. Batista Rodrigo O. A. Ozório 《European Journal of Lipid Science and Technology》2011,113(11):1332-1341
The current study was conducted to evaluate the effects of various dietary n?3/n?6 ratio on growth and lipid metabolism in gilthead seabream (Sparus aurata) juveniles. The fish were fed ad libitum on three isoproteic (52%), isolipidic (14%), and isoenergetic diets (21 MJ/kg), formulated to contain three different n?3/n?6 ratios: a high (3.8), medium (2.5), or low (0.9) ratio. Fish grew from 9.5 ± 0.1 g to 54.2 ± 0.7 g in 12 weeks. Growth rate (2.2% BW/day), voluntary feed intake (2.4 ± 0.1% BM/day), feed conversion ratio (1.38 ± 0.05), and net protein utilization (27.5 ± 1.0%) did not vary among treatments. In contrast, body lipid content and lipid deposition efficiency were significantly reduced in fish fed low n?3/n?6 ratio. Fish fed the highest n?3/n?6 ratio showed the lowest hepatic glucose‐6‐phosphate dehydrogenase (G6PD) activity (p = 0.02). The n?3/n?6 ratio decreased, while DHA/eicosapentaenoic acid (EPA) ratio increased significantly with decreasing dietary n?3/n?6 content. Among n?3 PUFA, the DHA and, particularly, the docosapentaenoic acid (DPA) showed the highest deposition rate both in muscle and liver. The lower deposition rate (<1) of linoleic acid (LA) and linolenic acid (LNA) suggests that a reduction in dietary n?3/n?6 ratio may stimulate their transport to the intermediary metabolism for energy production. 相似文献
35.
Hakan A. Cirpan Yucel Turker Erdinc Cekli 《AEUE-International Journal of Electronics and Communications》2001,55(2):119-122
A stochastic maximum likelihood approach for blind estimation of co-channel signals received at an antenna array is proposed in this letter. A hidden Markov model formulation of the problem is introduced and the Baum-Welch algorithm for the associated stochastic maximum likelihood estimation procedure is modified. The performance of the proposed algorithm based on the evaluation of approximate Cramer-Rao bounds is studied. Finally, some simulation results are presented. 相似文献
36.
Yolcu Gozde Oztel Ismail Kazan Serap Oz Cemil Palaniappan Kannappan Lever Teresa E. Bunyak Filiz 《Multimedia Tools and Applications》2019,78(22):31581-31603
Multimedia Tools and Applications - Facial expressions are a significant part of non-verbal communication. Recognizing facial expressions of people with neurological disorders is essential because... 相似文献
37.
Ana Rato Luís F. Pereira Sandra Joaquim Romina Gomes Cláudia Afonso Carlos Cardoso Jorge Machado José F. M. Gonçalves Paulo Vaz-Pires Leonardo J. Magnoni Ana M. Matias Domitília Matias Narcisa M. Bandarra Rodrigo O. A. Ozório 《Lipids》2019,54(9):531-542
The fatty acid (FA) profile of oysters generally reflects the dietary FA composition. Moreover, incorporation of FA into tissues is modulated by various metabolic factors, and final composition will depend upon the dietary sources, cumulative intake, and oysters' development stage. Thus, the aim of this study was to assess the impact of dietary incorporation of seaweed (SW) Ulva rigida, in replacement of traditional microalgae diet, on the FA composition of Pacific oysters Crassostrea gigas, during broodstock conditioning. The dietary conditioning consisted of direct replacement of microalgae (33% Tisochrysis lutea, 50.25% Skeletonema costatum, and 16.75% Chaetoceros calcitrans) by SW at four different substitution levels (0%, 25%, 50%, and 100% diet). The dietary docosahexaenoic acid (DHA) (22:6n-3) and eicosapentaenoic acid (EPA) (20:5n-3) contents showed a positive correlation with the dietary microalgae level. During the trial, oysters fed with higher percentages of microalgae revealed a depletion of DHA and accumulation of EPA. The 100% SW caused a significant reduction in oxygen consumption and, consequently, in the standard metabolic rate. Based on these results, a partial substitution of up to 25% of dietary microalgae seems to be a suitable alternative, because it elicited similar results to the commercial 100% microalgae diet. 相似文献
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40.
R Bahado-Singh O Deren U Oz A Tan D Hunter J Copel MJ Mahoney 《Canadian Metallurgical Quarterly》1998,179(2):514-519
OBJECTIVE: Our purpose was to develop a method of calculating the individual odds of Down syndrome on the basis of a combination of maternal age and multiple ultrasonographic parameters that can be used to counsel women at high risk who initially decline amniocentesis. STUDY DESIGN: Maternal age and ultrasonographic biometry data were collected prospectively on 3254 normal and 30 Down syndrome singleton fetuses between 15 and 24 weeks' gestation. Humerus length data were expressed as multiples of the normal median. Log transformation of the humerus length data permitted their expression in gaussian frequency distributions and the calculation of likelihood ratios for Down syndrome on the basis of humerus length. We also developed likelihood ratios on the basis of the degree of nuchal skinfold thickening and the presence or absence of hyperechoic fetal bowel and hypoplastic fifth digit. RESULTS: The ultrasonographic parameters and maternal age did not significantly correlate with each other and were significant independent predictors of Down syndrome. We therefore calculated the individual odds of Down syndrome by using the product of the age-related risk and the likelihood ratios associated with nuchal thickening, humerus length shortening, and the presence or absence of hyperechoic fetal bowel or fifth digit hypoplasia, respectively. At a Down syndrome risk level of >1:50, a 60.0% detection rate with 4.5% false-positive rate was observed with a screen-positive rate of 5.5%, positive predictive value of 1:10, and odds ratio (95% confidence interval) of 28.4 (12.8 to 64.0). CONCLUSION: This is the first report of individual odds calculation based on multiple midtrimester biometry parameters and maternal age. The screening efficiency is similar to that reported with triple-analyte serum screening. These data are useful for counseling women who are at increased Down syndrome risk and initially decline amniocentesis. 相似文献