On the simultaneous description of h‐bonding and dipolar interactions with point charges in force field models

H‐bonding and polar interactions occur together in real fluids, but are of different nature and have different effects on macroscopic properties. Nevertheless, both are usually described by point charges in force field models. Despite this, the two effects can be separated. A simple model fluid is studied: a single Lennard‐Jones (LJ) site with two opposing point charges q placed in the center of the LJ site and at a distance d. By suitably varying both d and q, the dipole moment μ is kept constant. Both μ and d are systematically varied to study the properties of the resulting models, including H‐bonding, which is determined using a geometric criterion from literature. d can be used for tuning the H‐bonding strength and, thus, polarity and H‐bonding can be adjusted individually. The study of a second related model with symmetrically positioned point charges does not reveal this separation. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2926–2932, 2015     

Heat pump drying of grape pomace: Performance and product quality analysis

Abstract

Grape is one of the most popular fruits and various types of grape have been cultivated by more than 100 countries around the World. The wine and juice industry produces large quantities of by-product, called grape pomace (GP) as an industrial waste and it consists of skins, seeds, and stems. Various processes such as separation, pressing, drying, and milling are applied to benefit from its health effects. In this study, the seeded black GP Kalecik karas? (Vitis vinifera) was dried in an assisted closed cycle heat pump dryer (HPD) designed for high-moisture products to investigate the drying behaviors of GP. The effects of drying air temperature on bioactive properties and the drying characteristics of GP, and performance of system have discussed. Experiments were carried out at two different temperatures (45 and 50°C) and air velocity of 1.0 m/s. It was seen that increasing temperature decreased the drying time, coefficient of performance of whole system (COP_ws), and specific energy consumption (SEC). The average values of COP_ws for temperatures 45°C and 50°C were calculated as 3.28 and 3.10, respectively. The drying efficiencies (DE) at drying air temperature of 45°C and 50°C ranged from 2 to 12% and from 2 to 15%, respectively. Additionally, result of analysis has indicated that using a HPD at lower temperatures increases performance of system despite of higher energy input. Bioactive properties of dried samples at drying air temperature of 45°C are better than 50°C. The results show that drying the GP at low temperature is more suitable for product quality. For this reason, heat pump may be preferred. It shows that this drying system with higher capacities in the future can be recommended as an alternative technique in terms of energy usage, drying time, and performance of system.     

质量功能展开方法及在虚拟仪器设计中的应用

以虚拟仪器为工程对象，研究了质量功能展开方法及其在虚拟仪器开发设计中的应用．分析了QFD在实现软件质量上的重要作用，并以虚拟振动分析仪设计为应用实例，介绍了该方法的应用．     

基于PCI总线的高速数据采集系统的研究

介绍了一种基于PCI总线的数据采集卡的设计思想和实现方案．本方案用两路低速A／D合成一路高速A／D，提高了工作的可靠性．应用CPLD技术实现PCI总线接口，并从状态机方面详细地介绍了PCI总线接口设计的时序控制．     

高压直流电路的开断

从基本原理出发，逐步探讨、分析了直流电路开断的基本问题；结合现代高压直流开断装置的典型电路工作原理，比较、推荐了高电压大功率直流电路的开断方法．     

汽轮发电机组振动故障分类推理综合诊断方法

分析了汽轮机组振动故障的属性，在故障诊断过程中选用模糊诊断方法，基础上提出了一种分类推理的综合诊断模型。该模型是按照故障征兆属性归类，通过分类识别缩小故障搜寻范围以利于故障的模糊诊断，然后再进行因子综合判断，对振动故障诊断的方法进行了研究。     

应用逆系统方法求解电力系统的非线性控制律

微分几何方法有效地解决了一系列的电力系统非线性控制问题，但因需要确定非线性变换，故必求解微分方程组，所以其求解控制律的过程比较繁琐。本文提出：由于电力系统数学模型形式的特殊性，非线性变换可直接确定，而无须求解微分方程组。另一方面，逆系统方法和微分几何方法本质是等价的，而逆系统方法的物理意义直观，不局限于仿射型系统，使用时仅需求导运算和代数运算，其求解控制律过程比较简捷，便于工程应用。作者以电力系统的汽门非线性控制为例，证明两种方法所得控制律是相同的。本文的结论可简化汽门控制，励磁控制，换流站控制，无功补偿器控制等问题的求解过程，亦适用于其它领域中类似的非线性控制问题。     

Optimization of atrazine removal from synthetic groundwater by electrooxidation process using titanium dioxide and graphite electrodes

ABSTRACT

Atrazine is used in agriculture and is known for its high toxicity. It therefore poses a risk to surface and ground waters, and human life. In this study, an electrochemical method was optimized for atrazine removal from SGW using TiO₂ and graphite electrodes. A comparison between one factor at a time period optimization and Box-Behnken design (BBD) optimization using RSM was carried out to select the optimum conditions. The results show excellent atrazine removal efficiency (99.70%) and close optimum conditions for both applied methods (pH 7 and 7.4; current 2.5 and 2 A and time 14 and 12.12 min, respectively).     

Energy analysis of hazelnut drying system‐assisted heat pump

In this experimental study, a proportional integral derivative (PID) controlled heat pump dryer was designed and manufactured. Heat pump dryer was tested drying of hazelnut and energy analyses were made. Drying air temperatures were changed as 50,45 and 40°C in the drying system. Drying air velocities were changed as 0.25 m s^?1 for 50°C, 0.32 m s^?1 for 45°C and 0.38 m s^?1 for 40°C. Heating coefficient of performance of whole system (COP_ws) of the heat pump dryer was calculated as 1.70 for 50°C, 1.58 for 45°C and 1.40 for 40°C drying air temperatures. Energy utilization ratio changed between 24 and 65% for 50°C, 17 and 63% for 45°C and 14 and 43% for 40°C drying air temperatures in the heat pump dryer. Copyright © 2008 John Wiley & Sons, Ltd.