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961.
Halil Kirnak Ergün Do?an Lütfiye Bilgel Kudret Berakato?lu 《Canadian Metallurgical Quarterly》2009,135(2):141-148
As a second crop, watermelons (Citrullus vulgaris, Crimson sweet) were grown in 2003 and 2004 in the Sanliurfa-Harran Plain in southeastern Turkey to determine the effect of preharvest water stress on fruit yield, quality (i.e., soluble solids contents and fruit size), leaf temperature, and some other physiological parameters. Preharvest drip irrigation treatments included (1) complete irrigation cutoff, dry (D); (2) full irrigation based on replenishment of soil water depleted from 0 to 90?cm soil profile (C); (3) 75% full irrigation (IR1); (4) 50% full irrigation (IR2); and (5) 25% full irrigation (IR3) with 3-day irrigation interval. Treatment plots received the same level of irrigation water until the fruit formation stage, except for Treatment D. Then, different water stress levels were imposed on treatment plots. Irrigation water applied to the five respective treatments were 636, 511, 395, 245, and 120?mm in 2003 and 648, 516, 403, 252, and 127?mm in 2004. Results indicated that fruit yield was significantly lowered by reduced water rates. The seasonal average yield response factor (ky) for both years was 1.0, but it was 0.97 for 2003 and 0.98 for 2004. The highest marketable fruit yield, obtained from treatment C, was 32.4?Mg?ha?1 in 2003 and 37.1?Mg?ha?1 in 2004. D, IR2, and IR3 treatments reduced most measured parameters, except for soluble solids contents (SSC). Both the fruit size and SSC were significantly affected by late-season irrigation management; individual fruit weights were significantly reduced, whereas SSC increased in the IR2 and IR3 treatments compared to the control values. The writers’ results clearly indicated that reduced preharvest irrigation was detrimental. Water use efficiency (WUE) was significantly affected by irrigation treatments. Even a 25% reduction in the irrigation amount caused a 15% reduction in marketable yield. This indicates that deficit irrigation in the ripening stage significantly increased water use efficiency. The study demonstrated that a moderate deficit irrigation, which is replenishment up to 50% of soil water depleted in the root zone, can be successfully used to improve WUE under semiarid climatic conditions. 相似文献
962.
Ahmet Rizaner Hasan Amca Kadri Hacolu Ali H. Ulusoy 《AEUE-International Journal of Electronics and Communications》2005,59(5):324-327
In this letter, we address the problem of mobile radio channel estimation at high channel efficiency using a small number of training symbols. A decision aided channel estimation scheme is proposed for slow fading multipath DS-CDMA channels. The approach is an extension of single-user least-square channel estimation. It is demonstrated that, due to the suggested channel estimate updating algorithm, the proposed scheme improves the channel estimation accuracy significantly. 相似文献
963.
964.
Mustafa Uludoğan Tahir ÇağIn Alejandro Strachan William A. Goddard III 《Scientific Modeling and Simulation》2001,8(2-3):193-202
We use ab-initio Quantum Mechanics to study the zero temperature phase diagram of BaO. We calculate zero temperature Equations of State of different crystalline phases [B1 (NaCl), B8(NiAs), B2(CsCl), and distorted B2] using Density Functional Theory (DFT) with the generalized gradient approximation (GGA). We find the B1 structure to be the thermodynamically stable one at zero pressure; followed by three pressure induced phase transitions. We find that at P=11.3 GPa BaO transforms from B1 to B8; at P=21.5 GPa from B8 to distorted B2. The distorted B2 phase continuously approaches the B2 structure, the phase transformation occurs at P=62 GPa. We also study the band structure of BaO in its high pressure (B2) phase. For P=60.5 GPa, we find a band gap of 3.5 eV in agreement with experimetal value. We find metallization at P=230.6 GPa. 相似文献
965.
Therapeutic effects of several medicinal plants and vegetables, which are commonly used as food and in folk medicine against many disease, are well known. Antioxidant capacities of Heracleum persicum Desf., Prangos ferulacea (L.) Lindl., Chaerophyllum macropodum Boiss. species from Apiaceae family were evaluated by determining their effects on DPPH radical scavenging, and lipid peroxidation inhibition, as well as their total phenolic contents. Potential natural glutathione-S-transferase inhibitors have gained great importance in the last decade especially because of the role of glutathione-S-transferases in developing resistance to chemotherapy. Selected plants were therefore further investigated for their influence on the activity of glutathione-S-transferase enzyme. 相似文献
966.
Assessment of finishing processes by exhaustion principle for textile fabrics: An exergetic approach
This study reveals the exergetic assessment of exhaustion processes for textile fabrics using actual operational data. The objective of the current work is to address the effects of the exhaust method parameters on exergy destruction and consumption rates. Additionally, a case study for cotton and polyester finishing processes was performed. The process temperature and time, water inlet temperature and liquor ratio were found to be the main parameters that affect exergy destruction rates. The effects of carry-over on exergy destruction rates were also investigated. It was shown that, 23% and 50% of total exergy destruction rate were occurred by the bleaching and the washing steps for cotton finishing, respectively, while 32% of total was accounted for the dyeing step of polyester finishing. The exergy efficiency of the finishing processes was obtained to be between 4.6% and 34.8% depending on the process variables. High temperature processes had higher exergy efficiency values. 相似文献
967.
968.
Ali Kemal Şehirlioğlu Cenk Özler 《The International Journal of Advanced Manufacturing Technology》2008,35(7-8):769-777
The response surface methodology (RSM) approach can be used to determine the optimal component tolerances in an assembly.
Frequently, response surface designs such as Box-Behnken design and central composite design are used in tolerance allocation
problems. In this article, mixture experiments, which are essentially constructed for designing a blend composition, are proposed
instead of response surface designs in order to observe the cost values. Also some advantages and disadvantages of mixture
designs are discussed. 相似文献
969.
Short chain alcohol esters of fatty acids can be used as diesel fuel. In this study, one step and two step base catalyzed room temperature transesterification reaction of used cooking oil was compared. In the two step base catalyzed process, for 1000 g of used cooking oil 4.2 g NaOH and 140 ml MeOH was used in the first step and 1.8 g NaOH and 60 ml MeOH was used in the second step. All reactions were done at 25 °C; the effects of water content and suspended particles on the yield were studied. The yields were easily determined by Thermo Gravimetric Analysis (TGA) instead of the usual Gas chromatography (GC) and the viscosity of products was measured by Ubbelohde type viscosimeter. It was found that two step processes gives a better yield (96%) than the one step process (86%). 相似文献
970.
M. Akif Şahman Mehmet Çunkaş Şeref İnal Fatma İnal Behiç Coşkun Uğur Taşkiran 《Advances in Engineering Software》2009,40(10):965-974
The cost optimization is a key element to determine the least-cost feed mixture according to animals’ nutrient requirements and the effective use of the sources. In this paper, the cost optimization of feeds is performed by genetic algorithm, considering the growing style and type, age, nutritional requirement and feedstuff costs for poultry and different types of animals. The proposed method is compared with linear programming approach to measure its performance. The obtained results show that Genetic algorithms could be applicable to the cost optimization of the feed mixtures. In addition, a software program is developed by using Delphi environment, which provides flexible, extensible and user-friendly framework for tuning the heuristic relevant parameters and improving the solution quality. 相似文献