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91.
92.
The binders of historic mortars composed of small grain sized silica (SiO2) and carbonated lime (CaCO3) are considered as the main part that give hydraulic character and high strength to the mortar. In this study, FTIR, SEM–EDS, LIBS and XRD spectroscopy were used to find out the weight ratios of CaCO3 to SiO2 in the binders of historic lime mortars. For this purpose, a series of pure calcium carbonate and silica mixture were prepared in ten combinations in varying ratios from 0.5 to 5. Calibration curve was prepared for each analysis by plotting the peak area or intensity ratios of CaCO3 to SiO2 versus the weight ratios of CaCO3 to SiO2. A good linear correlation coefficient was obtained for each analysis respectively. The analyses were then tested on the binder of the Roman mortar samples. The results indicated that FTIR, SEM–EDS and LIBS spectroscopy are convenient tools to determine the weight ratios of CaCO3 to SiO2 in the binders of mortars. But XRD spectroscopy is not convenient for quantitative analysis of binders due to the presence of varied amounts of amorphous or poor crystalline silica in their compositions. 相似文献
93.
BACKGROUND AND OBJECTIVE: To study the effect of topical prednisolone acetate after photorefractive keratectomy (PRK) using a 6.0-mm ablation diameter on the refractive and visual outcomes, corneal haze, corneal thickness, and corneal curvature in a prospective, double-masked, randomized manner. PATIENTS AND METHODS: Seventy-two eyes of 36 patients who had excimer laser PRK for correction of myopia ranging from -3.00 to -6.00 D (-4.11 +/- 0.84 D in eyes treated with steroids and -4.38 +/- 0.79 D in eyes treated with placebo; mean +/- SD) were enrolled. PRK procedures were performed using a 193-nm argon-fluoride excimer laser with 180-ml/cm2 fluence, a 10-Hz repetition rate, and a 6.0-mm ablation diameter. One eye of each patient was treated with the steroid (prednisolone acetate) and the other eye with placebo. Patients were observed for at least 12 months after PRK. RESULTS: There was no statistically significant difference between the steroid and the placebo groups with regard to refraction measurements that were taken postoperatively at 3 months (P = .39) and 12 months (P = .51). The corneas showed an increase in thickness after PRK in both groups, but the difference was not statistically significant at 12 months postoperatively (P = .45). The corneal haze score was not statistically different at any stage between groups (P = .30 at 3 months, P = .84 at 12 months). Keratometric data derived from corneal topography did not show any statistically significant difference (P = .85 at 3 months, P = .96 at 12 months). The rate of uncorrected visual acuity of 20/40 or more was 79.4% (27 eyes) in the steroid group and 70.5% (24 eyes) in the placebo group (P = .40). The rate of loss of 2 or more lines in best spectacle-corrected visual acuity was 5.85% (2 eyes) in the steroid group and 8.8% (3 eyes) in the placebo group (P = 1.0). CONCLUSION: Topical prednisolone acetate use for 3 months after PRK with a 6.0-mm ablation diameter has no effect on refractive and visual outcome, corneal haze, corneal thickness, and corneal curvature. 相似文献
94.
Purchasing managers face a complex problem when determining order quantities for multiple items in the presence of quantity discounts and resource limitations. In this paper, the problem is formulated as a mathematical programming model. An efficient solution algorithm is developed utilizing the Lagrangian relaxation approach. Extensive computational experiments are performed and the results are presented. 相似文献
95.
S Ozk?k AB Aras MA Esassolak AH Arican D Yalman A Haydaro?lu 《Canadian Metallurgical Quarterly》1995,50(6):443-447
Between March 1992 and February 1993, hyperfractionated radiotherapy (HRT) (1.2 Gy.fraction-1, twice a day, total dosage of 69.6 Gy) and simultaneous cisplatin (70 mg.m-2, 3rd and 23rd days of HRT) and etoposide (70 mg.m-2, 1-3rd and 20-23rd days of HRT) were applied to 27 patients with inoperable non-small cell lung cancer (NSCLC). Their Karnofsky performance statuses were 70-90%, and mean age was 52 (36-63). Two cases were stage II (one of the patients refused the operation and the other was medically inoperable because of insufficient ventilation), eight were stage IIIA and 17 were stage IIIB. No severe life-threatening grade IV acute toxicity findings were observed. Generally, acute side-effects were transient and did not require discontinuation of treatment. Tumour responses were as follows: complete response in six cases (23%); partial response in 19 cases (70%); and stable disease in two (7%). When complete response rates were compared according to stage, histological type, age group and weight loss, no statistically significant difference was found. Median overall and disease-free survival times were 14 months (95% confidence interval) (95% CI) 11-17 months and 10 months (95% CI 7-13 months), respectively. Twelve and 24 months overall and disease-free survival rates were 56 and 30%, and 36 and 24% respectively. No statistically significant difference was found in overall survival rates among epidermoid and nonepidermoid types, while the difference in disease-free survival was statistically significant. The acute and late complications of our HRT and simultaneous chemotherapy protocol were tolerable and the survival rates were encouraging. 相似文献
96.
Oommen J. Altinel I.K. Aras N. 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》1998,28(4):496-510
There are currently many vastly different areas of research involving adaptive learning. Among them are the two areas that concern neural networks and learning automata. This paper develops a method by which the general philosophies of vector quantization (VQ) and discretized automata learning can be incorporated for the computation of arbitrary distance functions. The latter is a problem which has important applications in logistics and location analysis. The input to our problem is the set of coordinates of a large number of nodes whose internode arbitrary "distances" have to be estimated. To render the problem interesting, nontrivial, and realistic, we assume that the explicit form of this distance function is both unknown and uncomputable. Unlike traditional operations research methods, which use optimized parametric functional estimators, we have utilized discretized VQ principles to first adaptively polarize the nodes into subregions. Subsequently, the parameters characterizing the subregions are learned by using a variety of methods (including, for academic purposes, a VQ strategy in the meta-domain). After an initial training phase, a system which achieves distance estimation attempts to yield an estimate of any node-pair distance without actually deriving an explicit form for the unknown function. The algorithms have been rigorously tested for the actual road-travel distances involving cities in Turkey and the results obtained are conclusive. Indeed, these present results are the best currently available from any single or hybrid strategy. 相似文献
97.
This study deals with the energetic and exergetic performance assessment of a combined heat and power system with micro gas turbine (MGTCHP). Quantitative energy and exergy balance for each component and the whole MGTCHP system was considered, while energy and exergy consumption within the system were determined. The performance characteristics of this MGTCHP system were evaluated using energy and exergy analyses methods. The energetic and exergetic efficiencies of the MGTCHP system are calculated as 75.99% with 254.55 kW (as 99.15 kW—electrical and 155.40 kW—hot water@363.15 K) and 35.80% with 123.61 kW (as 99.15 kW—electrical and 24.46 kW—hot water@363.15 K), respectively. The maximum energy loss and exergy consumption occur at 44.03 kW in the stack gas and 129.61 kW in the combustion chamber, respectively. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
98.
Networks and Spatial Economics - In this study, a two-stage stochastic integer programming model is developed with a centralized planning perspective to simultaneously address mitigation and... 相似文献
99.
Turkey, with its young population and growing energy demand per person, its fast growing urbanization, and its economic development, has been one of the fast growing power markets of the world for the last 20 years. It is expected that the demand for electric energy in Turkey will be 294 billion kWh by the year 2010 and 556 billion kWh by the year 2020. Turkey’s electric energy demand is growing 7% yearly. Because a substantial amount of Turkey’s energy need has been met by cogeneration facilities in recent years. Cogeneration facilities have an important role in Turkey’s energy strategy. While there were only four cogeneration facilities and the total capacity of them was 30 MWe in 1994, in 1999, 10.6% of total electric production was produced by these facilities. In accordance with the governmental decree numbered 85/9799, cogeneration is the technology which produces electricity and heat synchronously and autoproduction is the name of the firm which was founded for the purpose of producing electricity and heat. In this study, the development of autoproduction facilities in Turkey, which are the most convenient legal investment model for cogeneration investors, has been investigated. 相似文献
100.
Abdulkadir Bayır A. Necdet SirkecioğluN. Mevlüt Aras Ercüment AksakalH. İbrahim Haliloğlu Mehtap Bayır 《Food chemistry》2010
Total (TL), neutral (NL) and phospholipid (PL) amounts and fatty acid (FA) composition of female Salmo trutta caspius, Salmo trutta labrax and Salmo trutta macrostigma were investigated during one year. Twenty-three FAs were identified in both NLs and PLs. The principal FAs of both fractions were palmitic acid in saturated fatty acid, oleic acid in monounsaturated fatty acid, docosahexaenoic acid (DHA) in n-3 polyunsaturated fatty acids (n-3 PUFAs) and linoleic acid in n-6 PUFAs. The highest values for TLs, NLs and PLs were found in winter. As a general trend, the highest n-3/n-6 ratios and eicosapentaenoic acid (EPA) + DHA amounts were found in the winter and this coincided with the lowest gonado-somatic index. 相似文献