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The binary vapor–liquid equilibrium (VLE) data at the pressure of 101.3 kPa, which are 3,3-dimethyloxetane + methyl cyclohexane and 3-chloro-2,2-dimethyl-1-propanol + methyl cyclohexane, have been ...

Hypertrophic scar pain, pruritus, and paresthesia symptoms are major and particular concerns for burn patients. However, because no effective and satisfactory methods exist for their alleviation, the clinical treatment for these symptoms is generally considered unsatisfactory. Therefore, their risk factors should be identified and prevented during management. We reviewed the medical records of 129 postburn hypertrophy scar patients and divided them into two groups for each of three different symptoms based on the University of North Carolina "4P" Scar Scale: patients with scar pain requiring occasional or continuous pharmacological intervention (HSc pain, n = 75) vs. patients without such scar pain (No HSc pain, n = 54); patients with scar pruritus requiring occasional or continuous pharmacological intervention (HSc pruritus, n = 63) vs. patients without such scar pruritus (No HSc pruritus, n = 66); patients with scar paresthesia that influenced the patients' daily activities (HSc paresthesia, n = 31) vs. patients without such scar paresthesia (No HSc paresthesia, n = 98). Three multivariable logistic regression models were built, respectively, to identify the risk factors for hypertrophic burn scar pain, pruritus, and paresthesia development. Multivariable analysis showed that hypertrophic burn scar pain development requiring pharmacological intervention was associated with old age (odds ratio [OR] = 1.046; 95% confidence interval [CI], 1.011-1.082, p = 0.009), high body mass index (OR = 1.242; 95%CI, 1.068-1.445, p = 0.005), 2-5-mm-thick postburn hypertrophic scars (OR = 3.997; 95%CI, 1.523-10.487, p = 0.005), and 6-12-month postburn hypertrophic scars (OR = 4.686; 95%CI, 1.318-16.653, p = 0.017). Hypertrophic burn scar pruritus development requiring pharmacological intervention was associated with smoking (OR = 3.239; 95%CI, 1.380-7.603; p = 0.007), having undergone surgical operation (OR = 2.236; 95%CI, 1.001-4.998; p = 0.049), and firm scars (OR = 3.317; 95%CI, 1.237-8.894; p = 0.017). Finally, hypertrophic burn scar paresthesia development which affected the patients' daily activities was associated with age (OR = 1.038; 95%CI, 1.002-1.075; p = 0.040), fire burns (OR = 0.041; 95%CI, 0.005-0.366; p = 0.004, other burns vs. flame burns), and banding and contracture scars (OR = 4.705; 95%CI, 1.281-17.288, p = 0.020).

The ammoximation of ketones is an important chemical reaction, as oximes have a wide range of industrial applications. In this study, the process of preparing methyl ethyl ketone oxime by ammoximation of methyl ethyl ketone was studied. The modeling of the reaction unit was based on the kinetic data, and the reaction conditions were analyzed. Based on the total annual cost, an economic evaluation of the process was carried out, and a sequential iterative optimization algorithm integrating the reaction conditions was used to complete the process optimization. The minimum annual total cost was 2.41 × 107 USD/yr. The exergy of methyl ethyl ketone ammoximation to methyl ethyl ketone oxime process was analyzed, and the unit with the largest exergy loss was determined. The exergy loss rate was 65% for the minimum annual total cost. Considering exergy and annual total cost as the two optimization objectives, the process was comprehensively optimized by a multi-objective optimization algorithm. The annual total cost after multi-objective optimization was 2.55 × 107 USD/yr, which is 5.8% higher than minimum total annual cost, and the exergy loss rate was 64%, which is 1.54% lower than maximum exergy-loss rate. Compared with single-objective optimization, multi-objective optimization has a better comprehensive performance.

Cyclohexane and isopropanol (IPA) are commonly used as solvents for rapeseed oil peeling and low-temperature pressing. Owing to the existence of azeotropes, it is difficult to achieve efficient separation of wastewater by ordinary distillation. The theory of thermodynamics and molecular dynamics was used to explore the separation mechanism and identify optimal extractants. Furthermore, extractive dividing-wall column and pervaporation (PV) technology were used to decrease the energy consumption in the recovery process. Thermodynamic performance and environmental assessments were used to analyze the processes. Taking the total annual cost (TAC) and exergy as the objective, the processes were optimized by multi-objective optimization. The results showed that the TAC and CO2 emissions of the extractive dividing-wall column process were reduced by 7.46% and 5.89%, compared with the basic process. The TAC and CO2 emissions of the PV extractive distillation process were reduced by 13.98% and 15.09%. On this basis, the dynamic control performance was further explored by introducing a ±10% feed flow and composition disturbance. In addition, the influence of the composition on the economics of PV and distillation was studied. It was found that the PV-extractive distillation process has significant advantages over the basic process in the separation of azeotropes.

With the improvement of people's living standards, higher requirements are put forward for food safety, variety and quality. Edible oil is essential in people's life, but the production and processing process will produce a lot of waste, it is necessary to develop efficient and energy-saving treatment technology. Taking the wastewater containing ternary azeotropic system of cyclohexane-isopropanol-water produced in rapeseed oil production as an example, cyclohexane and isopropanol were separated and recovered by extractive distillation. Through the analysis of relative volatility, density functional theory and molecular mechanism, the suitable extractants of DMSO and EG were selected from the perspective of action mechanism. Aiming at the lowest economic cost, optimize the parameters of the process with single solvent and the mixed solvents by sequential iterative method, and further to determine the optimal process parameters and the optimal ratio of mixed extractant. In addition, the effects of single extractant and mixed extractant on the azeotropic system of extractive distillation were compared in terms of thermodynamic efficiency and environmental impact. The results shown that, compared with the single extractant, the extractive distillation process using the mixed extractant can save 30.71% and 16.71%, the thermodynamic efficiency was increased by 24.13% and 16.72%, GWP was reduced by 19.32% and 3.77%, AP was decreased by 19.26% and 3.43%. Combined with thermal integration technology, the economic cost was further reduced by 28.12%, the thermodynamic efficiency was increased by 10.49%, GWP and AP were reduced by 51.72% and 51.78% respectively on the basis of the optimal extractive distillation process with mixed extractants. The results shown that cyclohexane and isopropanol can be effectively recovered from the wastewater produced in rapeseed oil production by using mixed extractant and heat integrated energy-saving technology in extractive distillation process, which is of great significance for food safety, resource saving and environmental protection, and has guiding significance for the separation of other similar azeotropes.

The solubility of hydrogen sulfide in different mole ratios of ferric chloride and 1-butyl-3-methylimidazolium chloride ionic liquid (rFeCl3/[bmim]Cl, r = 0.6, 0.8, 1.0, 1.2, 1.4) at temperatures of 303.15 to 348.15 K and pressures of 100 to 1000 kPa was determined. The total solubility increased with the increase of pressure and the decrease of temperature. The solubility data were fitted using the reaction equilibrium thermodynamic model (RETM). The mean relative error between the predicted value and the measured value was less than 4%. Henry’s coefficient and the equilibrium constant of chemical reaction at each temperature were calculated. Henry’s coefficient first decreased and then increased with the increase of mole ratio, and increased with the increase of temperature. The equilibrium constant of the chemical reaction followed the same law as Henry’s coefficient. The chemical solubility was related to both Henry’s coefficient and the chemical equilibrium constant. H2S had the highest chemical solubility in FeCl3/[bmim]Cl at a mole ratio of 0.6 and a temperature of 333.15 K. The chemical solubility increased with the increase of pressure.

Laser cladding is an advantaged repairing technology due to its low heat input and high flexibility. With preheating wire by resistance heat, laser hot wire cladding shows better process stability and higher deposition efficiency compared to laser cold wire/powder cladding. Multi-pass layer were cladded on the surface of martensite precipitation hardening stainless steel FV520B by fiber laser with ER410NiMo wire. Wire feed rate and preheat current were optimized to obtain stable wire transfer, which guaranteed good formation quality of single pass cladding. Response surface methodology (RSM) was used to optimize processing parameters and predict formation quality of multi-pass cladding. Laser power P, scanning speed Vs, wire feed rate Vf and overlap ratio η were selected as the input variables, while flatness ratio, dilution and incomplete fusion value as the responses. Optimal clad layer with flat surface, low dilution and no incomplete fusion was obtained by appropriately reducing Vf, and increasing P, Vs and η. No defect like pore or crack was found. The tensile strength and impact toughness of the clad layer is respectively 96% and 86% of those of the substrate. The clad layer showed nonuniform microstructure and was divided into quenched areas with coarse lath martensite and tempered areas with tempered martensite due to different thermal cycles in adjacent areas. The tempered areas showed similar hardness to the substrate.

Hypertrophic scar pain, pruritus, and paresthesia symptoms are major and particular concerns for burn patients. However, because no effective and satisfactory methods exist for their alleviation, the clinical treatment for these symptoms is generally considered unsatisfactory. Therefore, their risk factors should be identified and prevented during management. We reviewed the medical records of 129 postburn hypertrophy scar patients and divided them into two groups for each of three different symptoms based on the University of North Carolina "4P" Scar Scale: patients with scar pain requiring occasional or continuous pharmacological intervention (HSc pain, n = 75) vs. patients without such scar pain (No HSc pain, n = 54); patients with scar pruritus requiring occasional or continuous pharmacological intervention (HSc pruritus, n = 63) vs. patients without such scar pruritus (No HSc pruritus, n = 66); patients with scar paresthesia that influenced the patients' daily activities (HSc paresthesia, n = 31) vs. patients without such scar paresthesia (No HSc paresthesia, n = 98). Three multivariable logistic regression models were built, respectively, to identify the risk factors for hypertrophic burn scar pain, pruritus, and paresthesia development. Multivariable analysis showed that hypertrophic burn scar pain development requiring pharmacological intervention was associated with old age (odds ratio [OR] = 1.046; 95% confidence interval [CI], 1.011-1.082, p = 0.009), high body mass index (OR = 1.242; 95%CI, 1.068-1.445, p = 0.005), 2-5-mm-thick postburn hypertrophic scars (OR = 3.997; 95%CI, 1.523-10.487, p = 0.005), and 6-12-month postburn hypertrophic scars (OR = 4.686; 95%CI, 1.318-16.653, p = 0.017). Hypertrophic burn scar pruritus development requiring pharmacological intervention was associated with smoking (OR = 3.239; 95%CI, 1.380-7.603; p = 0.007), having undergone surgical operation (OR = 2.236; 95%CI, 1.001-4.998; p = 0.049), and firm scars (OR = 3.317; 95%CI, 1.237-8.894; p = 0.017). Finally, hypertrophic burn scar paresthesia development which affected the patients' daily activities was associated with age (OR = 1.038; 95%CI, 1.002-1.075; p = 0.040), fire burns (OR = 0.041; 95%CI, 0.005-0.366; p = 0.004, other burns vs. flame burns), and banding and contracture scars (OR = 4.705; 95%CI, 1.281-17.288, p = 0.020).

The Cardinalized probability hypothesis density(CPHD) filter based on box-particle(BP) technology can effectively enhance the tracking accuracy of numbers of the multi-target tracking. And it also solved the tracking problem with unknown number of targets and missing targets. Point the problems of lack of tracking accuracy and missing tracking targets in the BP-CPHD algorithm, this paper presents some detailed measures about improving tracking. Based on the particle filter theory, we found that in the process of resampling, the particle size distribution cannot be optimized. So, in this paper, we replaced the traditional random sub sampling resampling method with the partition resampling method to improve the method of box-particle filter. Then we simulate and experiment the improved algorithm combined with CPHD filtering. The experimental results demonstrate that the improved method of tracking multi-target with the box-particle CPHD filter is more accurate than the original algorithm and the OSPA distance is smaller, so the effect of the improved tracking method is better.

the singlet oxygen generator (sog) is the heart of chemical oxygen iodine laser. a new swirl-jet-type sog was proposed which consists of a reaction part and a separation part. planar laser-induced fluorescence combined with maximum entropy method were used to study the droplet size distribution, and a modified muschelknautz model and computational fluid dynamics were used to simulate the separation efficiency of vapor and liquid phases. the results of the net reaction predict 99.2% conversion of chlorine and 42.2% yield of singlet oxygen, demonstrating the superiority of the new type of sog.

Toluene diisocyanate (TDI) is a widely used intermediate in the production of polyurethanes. Phosgenation reaction is the most important operation in the process of producing TDI, which is commonly performed in a jet reactor. Because of the high toxicity of phosgene, it is unpractical to evaluate the performance of the reaction by sampling intermediate products. To overcome this difficulty, first, a mapping table was created for reaction path and temperature. Next, various parameters that affect temperature, such as reaction path, ratio of phosgene, diethyl iso-phthalate (DEIP), etc. were investigated by simulation studies. The results show that the ratio of phosgene is the most important parameter. On the basis of the mapping table, easily available experimental reaction temperature data can be utilized to infer the reaction path, and consequently the performance of jet reactor can be predicted. The method was validated after being used in an experimental setup of 1000 tons/annum TDI capacity.

A modular approach to the formulation and a solution of mixed-integer non-linear programming (MINLP) problems are presented, which reduce the size of MINLP and the computational expenses effectively. The method decomposes the synthesis task into three hierarchical levels—the superstructure, the structure, and the modules, with the layer of modules being the most critical to the problem solution. The strategy has been implemented in a simulation environment in which the variables of interest are defined as implicit functions of the optimization variables. The implicit relationships are handled using a data-oriented process simulation technique (DOPS) that significantly simplify the simulation. The method has been effectively applied to two case studies, one from literature for the synthesis of hydrodesalkylation, and another from industrial process manufacturing methylene diphenylene diisocyanates. On presente une methode modulaire pour aborder la formulation et la resolution des problemes de programmation non lineaire a nombres entiers mixtes (MINLP), qui permet de reduire l'ampleur de la MINLP et les depenses de calcul de maniere efficace. Cette methode decompose la tâche de synthese en trois niveaux hierarchiques, la superstructure, la structure et les modules, la couche des modules etant la plus critique pour la resolution des problemes. La strategie a ete appliquee dans un contexte de simulation dans lequel les variables d'interet sont definies comme etant des fonctions implicites des variables d'optimisation. Les relations implicites sont manipulees a l'aide d'une technique de simulation des procedes orientees sur les donnees (DOPS), ce qui simplifie grandement la simulation. La methode a ete appliquee avec succes a deux etudes de cas, l'une venant de la litterature scientifique pour la synthese de l'hydrodesalkylation, et l'autre d'un procede industriel pour fabriquer des diisocyanates de methylene-diphenylene.

Soil erosion is a severe problem hindering sustainable agriculture on the Loess Plateau of China. Plot experiments were conducted under the natural rainfall condition during 1995–1997 at Wangdongguo and Aobao catchments in this region to evaluate the effects of various land use, cropping systems, land slopes and rainfall on runoff and sediment losses, as well as the differences in catchment responses. The experiments included various surface conditions ranging from bare soil to vegetated surfaces (maize, wheat residue, Robinia pseudoacacia L., Amorpha fruticosa L., Stipa capillata L., buckwheat and Astragarus adsurgens L.). The measurements were carried out on hill slopes with different gradients (i.e. 0 ° to 36 °). These plots varied from 20 to 60 m in length. Results indicated that runoff and erosion in this region occurred mainly during summer storms. Summer runoff and sediment losses under cropping and other vegetation were significantly less than those from ploughed bare soil (i.e. without crop/plant or crop residue). There were fewer runoff and sediment losses with increasing canopy cover. Land slope had a major effect on runoff and sediment losses and this effect was markedly larger in the tillage plots than that in the natural grass and forest plots, although this effect was very small when the maximum rainfall intensity was larger than 58·8 mm/h or smaller than 2·4 mm/h. Sediment losses per unit area rose with increasing slope length for the same land slope and same land use. The effect of slope length on sediment losses was stronger on a bare soil plot than on a crop/plant plot. The runoff volume and sediment losses were both closely related to rainfall volume and maximum intensity, while runoff coefficient was mainly controlled by maximum rainfall intensity. Hortonian overland flow is the dominant runoff process in the region. The differences in runoff volume, runoff coefficient and sediment losses between the catchments are mainly controlled by the maximum rainfall intensity and infiltration characteristics. The Aobao catchment yielded much larger runoff volume, runoff coefficient and sediment than the Wangdongguo catchment. Copyright © 2001 John Wiley & Sons, Ltd.

In order to separate the gas–liquid products from new ejector singlet oxygen generator (SOG) effectively, we designed a new type of gas–liquid cyclone. The classical Muschelknautz cyclone model method, the improved method and computational fluid dynamics (CFD) code's discrete phase model (DPM) and eddy diffusion concept (EDC) were used for the new type separator's calculation and simulation. The results show that: (1) Compared with classical Muschelnautz model, the improved Muschelknautz model can predict the cyclone's separation performance more accurately; (2) On the design conditions, the smaller droplets have more complex trajectories. For droplets larger than 3 μm, their separation efficiency is over 80% in the new separator; (3) The droplets' entrance locations affect the droplets' trajectories and separation efficiency, (4) The residence time which CFD predicts ranges from 1 to 50 ms and decreases with the droplets size increasing (5) The loss of O2(1 Δ) in the gas phase is less than 1% and it loses primarily on the gas–liquid contact reaction.

The key contaminant component (KCC) is defined to establish a superstructure model of water-using network synthesis for batch process with multiple contaminants, which uses storage tanks to eliminate the time limitations for water reuse or recycle, and its mathematic programming model is established and solved by nonlinear programming (NLP) method by a two-step solution strategy. Finally, an example is illustrated to show the efficiency of this method.

Multi-objective process synthesis can be described as a multi-objective mixed-integer nonlinear programming (MOMINLP) problem. To solve such problem, the main goal of this work is to develop a three-layer solution strategy, which includes simulation layer, synthesis layer and decision-making layer. Simulation layer is used to simulate and analyze the process system. In synthesis layer, NSGA-II is used to deal with the process data and generate an optimized population that transfers to simulation layer. In decision-making layer, the compromise solution is generated. The computer user interface is developed to support the data transmission. As a case study, MDA brine treatment process is used to illustrate the proposed strategy. The rigid process model and the optimization model are presented. The non-inferior solution curve is obtained and the final results are used to design industrial process.

The transportation and environmental systems are destroyed by runoff and soil losses from unpaved earthen hillside roads on the Loess Plateau in China. We constructed artificial road sections (2.0 m long, 0.55 m wide and 0.35 m deep) with loessial soil packed to give a representative bulk density of 1.5 g/cm3, and with different slope gradients (6°, 9°, 12°, 15° and 18°). Ten sections were planted with 50% grass coverage and another ten were bare as control treatments. Simulated rainfall (120 mm/h for 1 hour) was applied to the road sections and the hydraulic characteristics of the overland flow generated, and the amount of runoff and sediment yield produced over time, were examined. For any given slope gradient, grass inhibited overland flow as indicated by lower Froude and Reynolds numbers, higher friction and surface roughness as indicated by Manning and Darcy-Weisbach coefficients, and lower mean flow velocities. Lower impact energies of raindrops intercepted by the grass led to less surface seal formation and detachment of soil particles. This in turn resulted in amounts of runoff and sediment from the grassed roads with different slope gradients, which were 7.7%~13.1% and 47.3%~60.4% smaller than those from the bare roads, respectively. Reductions in sediment yields, which were linearly related to the slope gradient, were also attributable to reduced carrying capacity of the runoff. Therefore, grass growing on loessial earthen roads can mitigate soil losses effectively and, to a lesser degree, runoff amounts.

Scheduling for chemical batch process has been an active area of research over the past decade. The uncertainties of the process, which expand the scope and complexity, make the formulation and solution of the stochastic scheduling very intractable. This paper proposed a novel mathematical formulation which combined statistical probability theory with the deterministic scheduling; the discretion of the stochastic variables can be used to alleviate this difficulty and complexity. An example of batch process stochastic scheduling with uncertain processing time of uniform distribution indicated that the relationship between the deadline and the probability of optimal scheduling, and the distribution of the makespan of the optimal scheduling was studied. Result indicated the method is effective and reasonable.

A new method based on water cascade analysis (WCA) is presented to synthesize water use in batch process in this paper. This method includes two key steps: determine the target and design the water network. The fresh water demands for overall process or certain time intervals with and without storage tank is identified. Also the determination of overall pinch point, the storage capacity and the storage tank numbers is discussed. A two dimensional water network diagram, the time-purity level diagram, is introduced to help target and design the water network. We use two cases to illustrate the method, the results show it can achieve the optimal batch process water network efficiently.

The goal of this paper is to propose a new multiobjcetive process synthesis strategy in modular simulator environment. This paper presents a method of interpolation to find the tradeoff curve. An example is given to validate the reliability of the algorithm finally.

Based on the measured data and the model of plotted watershed hydrology, the benefit of sediment reduction by biological harnesses of soil and water conservation was studied in the watershed scale. The result indicated that the erosion modulus in Wangdonggou watershed, which were 1869 t.km-2, 1050 t.km-2, 383 t.km-2, and 504 t.km-2 in the periods of the sixth, seventh, eighth, and ninth five-year plans, respectively, were gradually reduced by comprehensive measures. Taken out the effect of rainfall, the sediment reduction by biological measures of soil and water conservation was increased by 24.1% and 22.4% in the periods of eighth and ninth five-year plans compared to that in the seventh five-year plan.