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排序方式: 共有378条查询结果,搜索用时 15 毫秒
21.
Borte Kose Hale Ozgun Mustafa Evren Ersahin Nadir Dizge Derya Y. Koseoglu-Imer Burcu Atay Recep Kaya Mahmut Altınbas Sema Sayılı Pelin Hoshan Doga Atay Esra Eren Cumali Kinaci Ismail Koyuncu 《Desalination》2012
Produced water, which is co-produced during oil and gas manufacturing, represents one of the largest sources of oily wastewaters. Therefore, treatment of this produced water may improve the economic viability and lead to a new source of water for beneficial use. In this study a submerged hollow fiber membrane bioreactor (MBR) has been studied experimentally for the treatment of brackish oil and natural gas field produced water. This type of wastewater is also characterized with relatively moderate to high amount of salt, oil and total petroleum hydrocarbons (TPH). However, the bacteria which are growing in conventional activated sludge and MBR cannot survive at these strict conditions, therefore acclimation of the bacteria is of vital importance. The performance of the biological system, membrane permeability, the rate and extent of TPH biodegradability have been investigated under different sludge age and F/M ratios. The results obtained by gas chromatography analyses showed that the MBR system could be very effective in the removal of TPH from produced water and a significant improvement in the effluent quality was achieved. 相似文献
22.
The adsorption of Th4+ ions was studied on composites of polyacrylamide (PAAm) with montmorillonite (Mt), clinoptilolite (Z) and zeolite Y (ZY), and after phytic acid (Phy) modification.The monolayer adsorption capacity was 0.33 and 0.65 mol kg? 1 for PAAm-Mt and PAAm-Mt-Phy, 0.07, 0.21 and 0.60 mol kg? 1 for Z, PAAm-Z and PAAm-Z-Phy, and 0.74, 0.89 and 1.18 mol kg? 1 for ZY, PAAm-ZY and PAAm-ZY-Phy. The enthalpy and entropy changes were positive for all adsorbents. The adsorption kinetics followed the pseudo-second order model indicating that the rate controlling step was chemical adsorption by ion exchange. The reusability tests for five uses proved that the PAAm-Mt and PAAm-Z were reusable and complete recovery of the adsorbed ions was possible. ZY and the composites modified with Phy were not reusable. The presence of foreign metal cations did not influence the Th4+ adsorption. The adsorbed Th4+ onto the columns was effectively recovered with diluted HNO3. 相似文献
23.
This paper reports an investigation into new connection types and their behaviors determined using full-scale experiments. T-shaped connections were created using the IPE standard profile. The aim of this study was to analyze the influence of T connections based on the IPE standard profile, height of beam to height of T-stub joint (H) of T-stub joints, and lengths (X) of T-stub joints on the behavior of steel connections, in order to provide the necessary data for improving Eurocode 3 and enable efficient use of residue IPE standard profiles and back to the consumption cycle. While the moment resistance values increased with an increase in H from Hmin to Hmax in model groups with X of 126 mm, and the energy dissipation increased with an increase in H from Hmin to Hmax and also with an increase in the lengths (X) of T-stub joints from 54 to 126 mm. 相似文献
24.
25.
The syntheses and characterization of 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) and quaternized 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) are described. The ground state electronic absorption spectra, photophysics and photochemistry of both dyes in DMSO as well as that of the quaternized compound in aqueous solution are also presented. A comparison of the photophysical and photochemical parameters of the two dyes revealed that quaternized 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) was a better photosensitizer than its unquaternized counterpart. The quantum yield values of fluorescence (ΦF), triplet state formation (ΦT) and singlet oxygen formation (ΦΔ) for the cationic dye were found to be 0.03, 0.68 and 0.66 respectively in DMSO; these values were higher than those for 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III), which exhibited values of 0.02, 0.66 and 0.63, respectively in DMSO. The values for the cationic dye in aq. solution were 0.02, 0.59 and 0.56 respectively, suggesting that the water-soluble quaternized 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) offers potential as a photosensitizer in photodynamic therapy treatment. 相似文献
26.
Soontae?KimEmail author Narayanan?Vijaykrishnan Mahmut?Kandemir Mary?Jane?Irwin 《Design Automation for Embedded Systems》2004,9(1):5-18
As technology scales down into deep-submicron, leakage energy is becoming a dominant source of energy consumption. Leakage energy is generally proportional to the area of a circuit and caches constitute a large portion of the die area. Therefore, there has been much effort to reduce leakage energy in caches. Most techniques have been targeted at cell leakage energy optimization. Bitline leakage energy is critical as well. To this end, we propose a predictive precharging scheme to reduce bitline leakage energy consumption. Results show that energy savings are significant with little performance degradation. Also, our predictive precharging is more beneficial in more aggressively scaled technologies. 相似文献
27.
Mahmut Sonmez 《International Transactions in Operational Research》2007,14(5):411-429
This paper describes the application of an evidential reasoning (ER)‐based decision making process to multiple‐criteria decision making (MCDM) problems having both quantitative and qualitative criteria. The ER approach is based on the decision theory and the theory of evidence and it uses the concept of ‘degree of belief’ to assess decision alternatives on each attribute. When faced with MCDM problems, evaluation and selection or ranking of alternatives appear to be both challenging and vital to arrive at a rational and robust decision. In the presence of both qualitative and quantitative evaluations in an MCDM problem, it is necessary, when using the ER‐based decision making process, to transform or convert quantitative data into a belief structure using a number of grades so that the converted belief structure and the original quantitative data are equivalent in values or utilities. This paper suggests three scenarios for data transformation and examines how the ranking of decision alternatives is changed when different scenarios of data transformation are used. Ranking of UK universities using the ER approach is illustrated as an example. 相似文献
28.
Faster product development and increased competition in retail industries is resulting in shorter and shorter product life-cycles. This phenomenon is making it more difficult for a firm to accurately estimate random demand of such products and to plan their one-time order quantity accordingly. In this paper, we develop a model to assess the multiple effects of coordinated - i.e., joint - stocking and prior-sale discount decisions: (i) on the reduction of demand uncertainty; (ii) on maximization of the expected profit; and (iii) on the probability of achieving or exceeding it. We develop the joint optimal decisions that maximize the expected profit and discuss a procedure for computing the probability that the realized value of the (random) profit will exceed its maximum expected value. We present qualitative results on the varying effects of joint decisions on increasing the expected profit and the probability of achieving or exceeding it. We also describe a detailed numerical study examining the effects of varying parameter values on the percentage increase in expected profit with joint decision making. The paper concludes with extensions of the model that can deal with more general situations. 相似文献
29.
The photophysical and photochemical properties of the tetra- and octa-12-crown-4-substituted zinc (II) phthalocyanines are reported for the first time in the scope of this work. The new compounds have been characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, electronic spectroscopy and mass spectra. General trends are described for photodegradation, singlet oxygen and fluorescence quantum yields, and fluorescence lifetimes of these compounds in dimethylsulphoxide (DMSO). Photophysical and photochemical properties of phthalocyanine complexes are very useful for photodynamic therapy (PDT) applications. The effects of the substituents on the photophysical and photochemical parameters of the zinc (II) phthalocyanines (5, 6 and 7) are also reported. The singlet oxygen quantum yields (ΦΔ) ranged from 0.48 to 0.78 are indicating the potential of the complexes as photosensitizers in applications of PDT. The fluorescences of the substituted ZnPc complexes are effectively quenched by benzoquinone (BQ). 相似文献
30.
Kıvanç Kılıç Baran Onal‐Ulusoy İsmail Hakkı Boyacı 《European Journal of Lipid Science and Technology》2007,109(2):157-164
A simple method that uses visible spectrophotometer data and an artificial neural network (ANN) was developed to determine edible oil color based on the L*a*b* format. The 100 oil samples consisted of nine pure oils, a sesame oil blend and three heated oils. Binary, ternary and quaternary mixtures of these 13 oils in different ratios were prepared, and absorbance values of the samples were measured in the visible region (380–700 nm). The absorbance values at wavelengths of 416, 456, 483, 537, 611 and 672 nm were used to train, validate and test the network. Strong correlations between the instrumental L*a*b*ΔE and the estimated L*a*b*ΔE were found for the test samples, with correlation coefficients (R2) of 0.989, 0.984, 0.996 and 0.992 for L*, a*, b*, and ΔE, respectively. The effects of number and combination of the wavelengths used for training of the ANN on the estimation capability of the network for the test samples were also investigated. Although a good agreement, average R2 of 0.991– 0 993 for L*a*b*, was obtained for combinations composed of three to six wavelengths with 483 and 537 nm in common, the best R2 value was obtained when all six wavelengths were used to train the ANN. The developed method is objective, cost effective and simple, and allows the color measurement with a basic visible spectrophotometer and disposable cuvettes. 相似文献