This paper focuses on the capacity uncertainty in water supply chains that occurs when facilities face disruption. A combination of scenario-based two-stage stochastic programming with the min-max robust optimization approach is proposed to optimize the water supply chain network design problem. In the first stage, the decisions are made on locations and capacities of reservoirs and water-treatment plants while recourse decisions including amount of water extraction, amount of water refinement, and consequently amount of water held in reservoirs are made at the second stage. The proposed robust two-stage stochastic programming model can help decision makers consider the impacts of uncertainties and analyze trade-offs between system cost and stability. The literature reveals that most exact methods are not able to tackle the computational complexity of mixed integer non-linear two-stage stochastic problems at large scale. Another contribution of this study is to propose two metaheuristics - a particle swarm optimization (PSO) and a bat algorithm (BA) - to solve the proposed model in large-scale networks efficiently in a reasonable time. The developed model is applied to several hypothetical cases of water resources management systems to evaluate the effectiveness of the model formulation and solution algorithms. Sensitivity analyses are also carried out to analyze the behavior of the model and the robustness approach under parameters variations.
A novel polyvinyl alcohol/alginate/zeolite nanohybrid adsorbent for the adsorption of Ni(II) and Co(II) metal ions was prepared by the casting method. The prepared adsorbent was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy as well as Barrett-Joyner-Halenda and Brunauer-Emmett-Teller analyses. The optimum adsorption conditions in terms of content of zeolite nanoparticles, adsorbent dosage, and initial pH were determined. The kinetic data for both ions were well described by the double-exponential kinetic model. The obtained Langmuir maximum adsorption capacities of Ni(II) and Co(II) metal ions were 81.51 and 79.58 mg g−1, respectively. The adsorption/desorption experiments showed a good performance after 5 cycles of adsorption. 相似文献
In the present study, the oleogel preparation with hydroxypropyl methylcellulose (HPMC) (0–2 g/100 g), sodium caseinate (CN) (0–4 g/100 g), beeswax (0–5 g/100 g), and oleogelation method (foam and emulsion template) was optimized using response surface methodology (RSM) to attain the desirable oil retaining ability, rheological, and textural characteristics. For all the chosen responses, the quadratic model was the best-fitting model with a determination coefficient of R2 > 0.91. Results exhibited that the HPMC and CN concentrations were the most influential tested factors on the oil binding capacity, textural, and rheological characteristics of the oleogels due to the formation of more complex and strong network. There was a significant improvement in oil binding capacity and structure recovery of samples by beeswax addition. To produce oleogel similar to industrial shortening, the optimization method was done based on maximum oil binding capacity and thixotropic recovery and other responses were chosen equal to those of shortening values (ɳa = 330 Pa.s, G′ = 276,543 Pa, A value = 164,308 Pa s rad−1, and firmness = 44.99 g). As regards the optimized level of structuring agents and responses (ɳa = 317 and 329 Pa.s, G′ = 249,782 and 260,997 Pa, A value = 180,022 and 180,373 Pa s rad−1, and firmness = 44.37 and 36.98 g corresponding to Optimization 1 and Optimization 2, respectively), fabrication of oleogels with at least 90 g/100 g trans-free and low saturated oil and attributes close to industrial shortening is possible. 相似文献
In this research, changes were observed in cell surface proteins of a typical strain of the Lactobacillus casei was investigated in response to acidic growth conditions. Two dimensional electrophoresis and Western blot analyses were
carried out to detect changes in relative abundance of proteins at the cell surface. The identity of the differentially expressed
proteins extracted by LiCl, a chemical routinely used to extract surface proteins of lactic acid bacteria, was determined
by MALDI-TOF/TOF MS. Many enzymes involved in glycolysis were up-regulated in the cell surface fraction following growth at
low pH, including enolase, lactate dehydrogenase, and glyceraldehyde-3-phosphate dehydrogenase. Several of these proteins
were also related to adhesion and generalized stress responses. It is demonstrated that growth of L. casei under acidic conditions caused molecular changes at the cell surface to develop an adaptive strategy corresponding to slower
growth at low pH. 相似文献
Cesium dihydrogen phosphate (CDP) powders were synthesized by cetyltrimethylammoniumbromide (CTAB), polyoxyethylene-polyoxypropylene
(F-68) and mixture of both surfactants F-68: CTAB with two molar ratios 0.06 and 0.12 as surfactant solutions at room temperature.
The synthesized CsH2PO4 is characterized by ICP, XRD, TEM, SEM, FT-IR, BET and IS techniques. Based on the width of the (011) XRD diffraction peak
and BET measurement, the average size of nanoparticles was ∼ 10 nm in diameter, while the TEM images indicate smaller size
than both techniques. The analysis reveals existence of P and Cs with mole ratio 1.02 ± 0.03 which is compatible to molar
ratio CsH2PO4 formula. The experimental results show that the conductivities increase in the order of CDPCTAB > CDP(F-68: CTAB)0.12 > CDP(F-68:CTAB)0.06 > CDPF-68. The sequence of increasing conductivity is in accordance with the ion exchange capacities of the samples that has direct
proportional effect on the proton mobility of samples. Indeed CTAB as cationic surfactant shows the highest proton mobility
in the as-obtained samples. 相似文献