Prediction of vapor-moisture equilibriums for a wood-moisture system using a modified UNIQUAC model

A modified UNIQUAC model has been extended to describe and predict the equilibrium relative humidity and moisture content for wood. The method is validated over a range of moisture content from oven-dried state to fiber saturation point, and over a temperature range of 20-70 °C. Adjustable parameters and binary interaction parameters of the UNIQUAC model were estimated from experimental data for Caribbean pine and Hoop pine as well as data available in the literature. The two group-interaction parameters for the wood-moisture system were consistent with using function group contributions for H₂O, -OH and -CHO. The result reconfirms that the main contributors to water adsorption in cell walls are the hydroxyl groups of the carbohydrates in cellulose and hemicelluloses. This provides some physical insight into the intermolecular force and energy between bound water and the wood material.     

两种盐溶液除湿器的建模与对比

描述了绝热型与内冷型两类平板溶液除湿器的结构特点,在盐溶液竖直降膜与湿空气顺流、充分发展的工况下,基于Navier-Stokes动量方程建立盐溶液与湿空气热、质传递过程耦合数学模型,以LiCl水溶液作为除湿剂,考虑气液界面处的剪切力边界条件,在恒壁温与绝热边界条件下,对两种具有相同尺寸规格的除湿器的除湿过程进行了数值模拟,得到沿高度方向上盐溶液温度、浓度和湿空气温度、含湿量的变化情况,并对两者在相同工况下进行对比,定量描述了两类除湿器在除湿性能上的差异.结果发现内冷型除湿器的出口溶液的温度更低,接近于冷却介质温度,而且处理后的湿空气的含湿量比绝热型除湿器低5.1 g·kg^-1,空气的出口温度也要低近10.5℃,但除湿溶液的浓度变化很小,进、出口浓度差不到1％.     

基于评估模型的化工装置投入产出

针对化工装置生产过程中计量方式的多样性以及计量时效的滞后性等问题,通过引入装置界区和评估模型的概念,提出了一套基于“评估模型”的装置投入产出量推算方法,而且在实际生产过程中,也具有可操作性。该方法将为化工生产装置的班产和班耗数据的计量和推算提供有力的支持,并对装置的生产过程提供监控依据。     

A solar desalination system using humidification–dehumidification process: experimental study and comparison with the theoretical results

In this study, influence of the different system operating conditions on the performance of a solar desalination system using humidification-dehumidification process have been investigated experimentally under the climatological conditions of Ankara (40°N, 33°E), Turkey. An experimental set-up that consists of a double-pass flat plate solar air heater with two glass covers, pad humidifier, dehumidifying exchanger and water storage tank was designed and manufactured. Working principle of the set-up is based on the idea of closed water and open-air cycles. A series of tests were performed on it in outdoor environment, in order to assess the effect of mass flow rate of the feed water, process air and cooling water, double-pass flat plate solar air heater, initial water temperature and amount of the water inside the storage tank on the productivity of the system. Additionally, an evacuated tubular solar water heater unit was integrated to the existing system and the effect of this integration on the performance of the system was examined. Solar radiation, wind speed, relative humidity, mass flow rate of the feed water, process air and cooling water, mass of condensate water and temperatures at various locations were obtained during the experiments.

The results of the experimental study showed that under certain operating conditions, the system productivity decreases about 15% if double-pass solar air heater is not used and significant improvement on the productivity of the system is achieved by increasing the initial water temperature inside the storage tank. In addition, productivity of the system increases with increasing the feed water mass flow rate and quantity of water inside the storage tank. However, productivity of the system remains approximately the same when the air mass flow rate is increased. Moreover, increasing the cooling water mass flow rate results in the improvement on the productivity of the system investigated. Finally, results obtained from the present investigation were compared with the theoretical study and a good agreement between them is observed.     

基于皮肤本态数据库的中青年女性面部皮肤综合状态评价模型构建

从中国女性皮肤本态数据库(北京工商大学)中随机抽取22～42岁女性志愿者1 085例,采集志愿者的皮肤数据,通过相关性分析初步降噪,得到皮肤状态核心指标,并采用KMO检验和巴利特球形检验方法进行检验。根据主成分分析法计算评价模型的各项系数,最终构建皮肤状态综合评价模型。皮肤状态相关的核心指标包括:年龄、皮肤总弹性、皮肤光泽度、黑色素含量、血红素含量、水分含量、经皮水分散失量、肤色ITA°、油脂含量、毛孔数量等10项。该模型对女性的综合皮肤状态给予客观的量化判定,弥补了肉眼判断受到的周围环境以及个人主观意识的影响,解决了皮肤评价的时空限制,采集相关指标数据即可对女性皮肤进行有效评价。研究结果可为女性皮肤状态综合判定提供技术支持。     

A study of the emotional evaluation models of color patterns based on the adaptive fuzzy system and the neural network

Proposed in this article are two kinds of emotional models based on the neural network and the adaptive fuzzy system that can transform the physical features of a color pattern into its emotional features. The purpose of this system of models is to evaluate the neural network and adaptive fuzzy system for its ability to model psychological experimental data in a way similar to what a human expert would do. Construction of the models was motivated by Soen's psychological experiments, in which he found that such physical features as average hue, saturation, and intensity and the dynamic components of color patterns affected the emotional features represented by a pair of adjectives having opposite meanings. One is based on the neural network in the proposed models, and the other consists of two adaptive fuzzy rule bases and a γ model, a fuzzy set operator, to fuse the evaluation values produced by them. The proposed models showed superior performances compared to Soen's model in the approximation of nonlinear transforms, whereas the latter showed an advantage in obtaining the linguistic interpretation from the trained results. The evaluated results of color patterns can be used to construct a emotion‐based color‐pattern retrieval system, which would be able to recommend the color patterns of a desired human feeling. We believe that in linguistic queries of human feelings, these color‐pattern retrieval systems would be able to select from a gallery the corresponding textile designs, wallpapers, or pictures. © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 208–216, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10052     

液位控制系统干预下小孔全过程泄漏速率模型

泄漏速率是计算泄漏量、确定泄漏持续时间及评估泄漏风险的前提和基础,通过搭建液相储罐小孔泄漏实验系统,构建不同泄漏场景,对比液位控制系统干预下的泄漏速率变化情况,并结合泄漏速率模型计算值进行分析。结果表明：液位控制系统响应后,泄漏速率下降速度变缓,并随时间推移逐渐开始回升,最后稳定在某值处达到稳态泄漏,进出流量对储罐小孔泄漏速率的影响基本可忽略。通过改进储罐泄漏经典公式,建立基于实际液位控制系统干预条件下的储罐小孔泄漏速率模型,提出泄漏孔口高压修正系数计算方法和模型,通过验证分析证明该模型可有效提高液位控制系统干预下泄漏速率计算精度。     

Quantitative evaluation of perceived whiteness based on a color vision model

This article describes a new perceived whiteness index, C/V index, which focuses on the brightness‐enhancement effect of color components included in the spectral reflectance factor distribution of approximate white objects or in the spectral power distribution of illuminations. The index is developed on the basis of a color vision model. The perceived whiteness of 18 approximate white samples was evaluated, and then a predictability of the index was compared with 17 types of existing whiteness indices. As a result, the C/V index was one of the indices indicating the best predicting performance. The aforementioned findings show that the C/V index is effective in evaluating the perceived whiteness of approximate white objects and the brightness‐enhancement effect of color components is an important factor in determining the perceived whiteness. © 2009 Wiley Periodicals, Inc. Col Res Appl, 2010     

一种基于PWA模型的控制策略在连续搅拌反应釜中的应用

在化工系统实际运行过程中,常常会出现一些不正常的工作状态,为了使系统运行状态能够避开这些不正常的工作状态,往往需要对控制器进行重构。针对这种情况,本文阐述了一种基于分段仿射模型的控制策略,该控制策略采用显式模型预测控制算法对系统进行控制,当检测到系统出现异常工作点时,先对系统进行形式验证,根据验证结果,再决定是否进行控制器重构,这样,既大大节约了生产时间和成本,也提高了控制效率。将该控制策略应用到连续搅拌反应釜系统中,取得了显著的应用成效。     

Pore‐size evaluation and gas transport behaviors of microporous membranes: An experimental and theoretical study

A modified gas‐translation (GT) model based on a GT mechanism was successfully applied to the pore‐size evaluation and gas transport behavior analysis of microporous membranes with different pore‐size distributions. Based on the gas permeation results of three microporous membranes derived from different alkoxides, the effects of activation energy and the selection of a standard gas on the pore‐size evaluation were discussed in a comparative study. The presence of nano‐sized defects had an important influence on the gas permeation performance of microporous membranes, depending largely on the original pore size of the membrane in question. Moreover, the gas‐separation effect of the pore‐size distribution in a silica membrane was theoretically studied and revealed a significant increase in gas permeance for relatively large gas species but not for small ones. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2268–2279, 2015     

A study of a simulated moving bed adsorber based on the axial dispersion model

On the basis of the axial dispersion model, the concentration profiles for a simulated moving bed adsorber were theoretically predicted. Experimentally, an apparatus consisting of four sections was employed. Glucose and sorbitol were separated from the liquid dissolved with these components both co-currently and counter-currently. The experimental results seemed to support the predicted curves.     

Feasibility study and performance assessment for the integration of a steam-injected gas turbine and thermal desalination system

This study proposes a systematic approach for retrofitting a steam-injection gas turbine (SIGT) with a multi-effect thermal vapor compression (METVC) desalination system. The retrofitted unit's product cost of the fresh water (RUPC) was used as a performance criterion, which comprises the thermodynamic, economic, and environmental attributes when calculating the total annual cost of the SIGT–METVC system. For the feasibility study of retrofitting the SIGT plant with the METVC desalination system, the effects of two key parameters were analyzed using response surface methodology (RSM) based on a central composite design (CCD): the steam air ratio (SR) and the temperature difference between the effects of the METVC system (?T_METVC) on the fresh water production (Q_freshwater) and the net power generation (W_net) of the SIGT–METVC system. Multi-objective optimization (MOO) which minimizes the modified total annual cost (MTAC) and maximizes the fresh water flow rate was performed to optimize the RUPC of the SIGT–METVC system. The best Pareto optimal solution showed that the SIGT–METVC system with five effects is the best one among the systems with 4–6 effects. This system under optimal operating conditions can save 21.07% and 9.54% of the RUPC, compared to the systems with four and six effects, respectively.     

Experimental and modeling study for the removal of formic acid through bulk ionic liquid membrane using response surface methodology

Abstract

In this study, formic acid removal from its aqueous solutions through bulk ionic liquid membrane (BILM) was investigated. Tributyl phosphate (TBP) as a carrier in imidazolium-based ionic liquids was used. D-optimal design based on response surface methodology has been applied to investigate the effect of various operating factors. Initial formic acid concentration, TBP concentration, and NaOH concentration were selected as numerical factors, and ionic liquid type was chosen as a categorical factor. The model equations were obtained to determine BILM process behavior. The removal efficiencies, represented by the extraction and stripping efficiencies, were calculated from the experimental data. The highest removal efficiencies were determined at higher concentration values of TBP and NaOH. All ionic liquids studied in this study had good transport selectivity for the removal of formic acid. The design study showed that BILM is an effective method for the removal of formic acid from the water.     

Preparation and characterization of a model system for the study of monolayers and multilayers of vanadia supported on titania

A model system for the study of structural and chemical properties of monolayers and multilayers of vanadium oxide immobilized on titania is presented. Investigation of the planar oxide-oxide interface by XP, UV and IS spectroscopy indicated that vanadium immobilized by a single impregnation step exists as an incomplete heterogeneous layer containing well dispersed V⁴⁺ species. Increase of the vanadia loading by multiple impregnations led to vanadia agglomerates with higher apparent oxidation state of the vanadium. TD spectroscopy with O₂ and CO₂ as probe molecules revealed that the chemical reactivity of the vanadia surface species depends on their structure. The surface containing well-dispersed vanadia species exchanged oxygen more easily and showed pronounced interactions with CO₂.     

Statistical Analysis of the Effect of the Temperature and Inlet Humidities on the Parameters of a PEMFC Model

An individual PEM fuel cell 6‐parameter mechanistic model was developed. In parallel, experimental polarization curves were obtained at different temperature and inlet gas humidities conditions. The 6 model parameters were determined by fitting the semi empirical model to the experimental curve using a non linear regression method. Finally, a statistical analysis was carried out in order to determine which operating conditions (temperature and inlet humidities) have a significant effect on which model parameters. A black box model was built in order to relate the model parameter values to the significant operating conditions for each one of them. The obtained model was able to satisfactory reproduce the experimental behaviour of the system at low current densities.     

Energy and economic analysis of a hydrogen and ammonia co-generation system based on double chemical looping

In this work, a model of hydrogen production by double chemical looping is introduced. The efficiency benefit obtained was investigated. The chemical looping hydrogen generation unit is connected in series to the downstream of a chemical looping gasification unit as an additional system for 100 MW·h coal gasification, with the function of supplementary combustion to produce hydrogen. Using Aspen Plus software for process simulation, the production of H_2 and N_2 in the series system is higher than that in the independent Chemical looping gasification and Chemical looping hydrogen generation systems, and the production of hydrogen is approximately 25.63% and 12.90% higher, respectively; The study found that when the gasification temperature is 900 °C, steam-carbon ratio is 0.84 and oxygen-carbon ratio is 1.5,the hydrogen production rate of the system was the maximum. At the same time, through heat exchange between logistics, high-pressure steam at 8.010×10~4 kg·h~(-1) and medium-pressure steam at 1.101×10~4 kg·h~(-1) are generated, and utility consumption is reduced by 61.58%, with utility costs decreasing by 48.69%. An economic estimation study found that the production cost of ammonia is 108.66 USD·(t NH_3)~(-1). Finally, cost of equipment is the main factors influencing ammonia production cost were proposed by sensitivity analysis.     

Experimental evaluation of a kinetic method for the study of non-catalysed heterogeneous reactions in solid–liquid systems: Leaching of apatite by dilute nitric acid

A method for evaluating the formal reaction order n of a chemical reaction is proposed, based on a kinetic equation describing chemical dissolution of solid particles in a batch reactor. The evaluation is based on the fact that the function expressing the dependence of the conversion, X_B, on the term c_A0ⁿt has the same course for different initial concentrations of the liquid reactant, c_A0 (t denotes time), at constant temperature and ratio of reactants. The measured dependences of the conversion on the time give a function, f_s(X_B), characterizing changes of the solid surface area during the reaction. Minimization of deviations of this function permits the influence of mass transfer between the bulk of the liquid and the solid surface on the measured formal reaction order to be corrected. Knowledge of the value of n and the function f_s(X_B) enables the derived kinetic equation to be integrated numerically and the dependence of the conversion on time to be calculated. A set of experimental data measured during dissolution of natural apatite in dilute nitric acid (0.1–1.5 mol dm⁻³) at 20°C was used for demonstration of the proposed method. © 1998 SCI     

助磨介质作用下旋窑熟料微细化过程及其效果评价

通过对助磨介质作用下不同粉磨细度的旋窑熟料所配制的硅酸盐水泥的物理性能检测,对助磨介质作用下旋窑熟料的微细化效果进行了评价。结果表明,对水泥熟料来说,早期的快速水化不一定能得到高强度的水泥,因此熟料微细化的评价要从水化性能和粉磨能耗上综合考虑,在实验中,旋窑熟料的最佳粉磨细度为5 000m2/g,而加入助磨剂可显著降低粉磨能耗,在达到同样效果时缩短25％的粉磨时间。     

Quantitative study on cross-linking reactions of oxygen groups during liquefaction of lignite by a new model system

Cross-linking reactions (CLR) of oxygen groups during liquefaction of lignite were quantitatively studied by a new model system. Chinese Yitai lignite (YT) was first oxidized by nitric acid at 70 °C and about 98% of the oxidized sample could be dissolved in tetrahydrofuran (THF) at room temperature. Then benzyl alcohol, PhCH₂OH (BA), as a model compound was added into the oxidized coal, also acted as solvent in the subsequent liquefaction. Temperature-programmed reactions (TPR) at liquefaction conditions under hydrogen atmosphere were performed to evaluate the CLR by quantitative analysis of THF-insoluble solid products (THFI) after reaction. Extensive CLR were observed even under high pressure of H₂ at 200-400 °C, and more than 51.7% and 81.2% of the THFS fraction was converted into the THFI at 300 °C with tetralin (TET) and BA as solvent, respectively. The THFI fraction was almost solely caused by the CLR, which makes it possible to quantitatively study the CLR by analyzing the amount of the cross-linked solid products (CSP). The pyrolysis behaviours of CSP and oxidized coal were examined by TG. Other model compounds containing oxygen-functional groups (alcohol, phenol, carboxyl, carbonyl and ether groups) can also be used in this model system to study CLR of oxygen groups in low-rank coals.     

基于最小二乘支持向量机的MIMO线性参数变化模型辨识及预测控制

将现有的面向单输入单输出系统的基于最小二乘支持向量机的参数变化模型辨识算法(SISO-LSSVM-LPV), 推广到多输入多输出系统, 实现了面向多输入多输出系统的基于最小二乘支持向量机的参数变化模型辨识算法(MIMO-LSSVM-LPV), 进一步结合基于遗传算法的预测控制算法(GA-MPC), 提出并实现了MIMO-LSSVM-LPV+ GA-MPC的建模控制一体化新架构。仿真结果表明, 该辨识算法可逼近复杂非线性MIMO系统, 辨识精度高, 并且保留了线性回归低计算量的优点, 结合了GA的MPC可实现最优控制量的在线实时寻优, 并取得了良好控制效果。