Study of the Ozonation of a Dye Using Kinetic Information Reconstruction

In this study, the kinetic information reconstruction method is applied to measure the degradation of a dye in an ozonation gas-liquid reactor. The application of this method combined with the study of the ozone gas phase concentration has made possible a deeper study of the fast reaction between ozone and blue indigo trisulfonate. For this kinetic study different rigorous mathematical models based on Film Layer Theory, Surface Renewal Model and Penetration Theory have been used.     

Electrical Properties of PTCR Barium Titanate

When properly doped, barium titanate ceramics display positive temperature coefficient resistance (PTCR) behavior. This has been proved to be a Schottky barrier type of grain-boundary effect. However there has not yet been a complete point-to-point comparison between the experimental data and theory for the entire set of the material nonlinear dielectric properties. In this study, a methodology has been developed which allows the study of the depletion layer dielectric properties while the PTCR effect is being investigated. An equivalent dielectric constant, the value of which is to be determined from this experiment, is treated as an average of the dielectric properties of the depletion layer and is used to analyze the grain-boundary resistance and capacitance data based on a simple double-depletion-layer model. The theoretical relationship between this equivalent dielectric constant and the material dielectric properties is also explored in this study.     

Role of thermophoresis in the deposition of fume particles resulting from the combustion of high inorganic containing fuels with reference to kraft black liquor

Fume generation and deposition are key processes in many manufacturing operations. These include the manufacture of carbon black and silica fume. In addition to its role in these processes, fume deposition is an important phenomenon in the combustion of fuels containing inorganic compounds. One combustion process where fume deposition presents special problems is the burning of kraft black liquor. This paper presents a laboratory study of fume deposition with emphasis on the kraft recovery boiler. A unique aspect of this study was the construction of an experimental system capable of generating sodium sulfate, sodium carbonate, and sodium chloride fume particles. With this experimental system, variables such as particle size, particle gas-phase concentration, particle composition, temperatures and gas flow rates could be independently controlled. The major objectives of this study are to: (1) determine the mechanisms responsible for particle deposition within the kraft recovery furnace, (2) provide experimental data to support the hypothesis that thermophoresis is the major mechanism responsible for deposition of fume type particles, and (3) correlate the experimental results obtained in the study to deposition rates observed in operating recovery furnaces. The experimental results obtained in this study showed that thermophoresis is the dominant mechanism for fume deposition under conditions similar to those existing in the kraft furnace. This result is well supported by the experimental data. For example, thermophoresis theories accurately predict effects of the temperature, particle concentration, and particle size that were observed in this study. The experimental results obtained in this study were extrapolated to deposition in an operating kraft furnace and found to provide a reasonable prediction of boiler bank deposition. Although the study was targeted at the kraft recovery boiler, the results should be applicable to the combustion of any fuel containing a high level of inorganic material.     

炼焦中煤解离再选的重要性及研究现状

论述了保护稀缺炼焦煤的重要性,提出对选煤厂炼焦中煤进行解离再选的方案;以印度某公司炼焦原煤及我国西南某选煤厂炼焦中煤的浮沉资料为例,说明了中煤解离再选的可行性,介绍了国内外炼焦中煤再选研究现状,建议我国炼焦煤选煤厂进行中煤再选研究。     

化工材料pH值例行分析及应用

pH值是指原材料水溶液的pH值,所以pH值测定都依赖于水,测定过程总是将材料转变为水溶液、水萃取液或水分散体,然后进行测定.由此可见,必须首先进行水的pH值研究,然后才能谈及材料的pH值问题.对pH值的测定方法依材料的性质不同而不同,很有必要研究一套较通用的测定方法.从研究水的pH值开始,其后在对各种非金属材料的pH值例行分析进行初探.     

窑炉火焰空间辐射传热数学模型探讨

本文从能量平衡原理出发,以多孔推板窑为例,提出了窑炉火焰空间传热过程的二维通量辐射数学模型并进行了求解。作为应用探讨,文中给出了多孔推板窑设计计算实例,从而为窑炉火焰空间辐射传热过程数字模拟指明了方向。     

A review of methods for determining structural fire severity—Part II: Analysis and review

There is a risk of a building suffering unsustainable structural damage in the event of a large fire. Therefore, it is necessary to design buildings to withstand expected fires. A widely used simplified calculation method is the so-called “time-equivalence” method. There are significant concerns about the suitability of this method. This paper is part II of a twofold study examining the state of the art of time-equivalence methods. The purpose of this paper is to identify methods and/or analysis concepts which show the potential for use in modern design. A SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis is used for this purpose. However, as there is a large number of time-equivalence methods to assess, a numerical case study is first undertaken to identify methods which have sufficient accuracy to warrant further study. These analyses found that, while none of the time-equivalence methods studied have sufficient accuracy for use in their present form, the methods derived using the equal energy concept provide a good basis to model the effects of fire on a structure. This study recommends that a new time-equivalence method be developed using the equal energy approach.     

The residual stress of magnet wire and crazing

It is well known that crazing occurs sometimes when a magnet wire is immersed in an impregnating varnish after coiling. A quantitative study between residual stress of a magnet wire film and crazing is presented in this paper by using a magnet wire having poor adhesive strength between the film and the conductor. The residual stress of a magnet wire was found to be maximum in the range of 3–5% elongation. A morphological study of crazing which occurred in crosslinked and linear polymers is also described in this paper.     

Experiences with the method of trimethylsilylation for the study of soluble silicates

It is possible to prepare organic derivatives of silicate groups in which each terminal oxygen is blocked by a trimethylsilyl group. This can provide a route for the preparation of new polymers. It can also provide information about the structure of the original silicate group, provided that this is faithfully reflected in the structure of the derivative. This will be true only if the silicate groups do not undergo any polymerisation, depolymerisation or rearrangement while the derivatives are being formed. The method has previously been successfully applied to a wide variety of silicates; this paper describes, in particular, attempts to apply it to the study of sodium silicates. An assessment is given of the difficulties involved and of the utility of the method for this type of study.     

Design and Development of Highly Efficient Rectangular Column Structured Titanium Oxide Photocatalysts Anchored onto Silica Sheets

The purpose of this study is to design and develop highly efficient photocatalysts that can be anchored onto a substrate, and to this end we have prepared a titanium oxide photocatalyst using a wet process or a dry process. The results of this study led to the successful development of highly efficient rectangular column structured titanium oxide photocatalysts which could be anchored onto silica sheets.     

Synthesis of the knowledge model for fault diagnosis using qualitative simulation

Fault diagnosis requires the knowledge models which describe the behavior of the chemical processes. However it is cumbersome and time consuming work to generate these models. Also the knowledge acquisition required for generation is difficult. The objective of this study is to examine whether the knowledge aquisition for fault diagnosis knowledge models, especially bottom-up models, is possible through qualitative simulation. Qualitative simulation is based on the study of modeling, representation of feedback control and state transition using the QSIM algorithm. Also in this study, qualitative simulation is applied to a buffer tank level control system using the simulation strategy of this paper. The results of the simulation show several behaviors of the processes and the usability for the generation of a knowledge model. However when several different results of simulation are generated, some are spurious solutions which result from insufficient information.     

Characterization and modeling of sintering of polymer particles

An experimental study of simultaneous sintering of several particles has been carried out using spherical polymer grains. Considering rotational molding condition, coalescence of several grains in contact, happens simultaneously on internal surface of the mould. Theoretical model based on the effect of surface tension and viscosity can accurately predict the coalescence of a pairs of grains. However, it was observed in this study that coalescence rate changes with presence of neighboring grains and their position and the theoretical model proposed for two grains, is not able to predict the coalescence rate of mutli‐grains. Based on this finding, we have modified this model with taking into account the effect of neighboring particles in the sintering rate of multi‐grains. Obtained modified model is capable of predicting the multi‐grains sintering rate observed in this study. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

云南麦饭石的成份及毒理学研究初探

本文通过对云南鹤庆麦饭石进行成份测定和毒理实验研究，并与中华麦饭石进行比较研究，为云南麦饭石的开发利用指出了广阔的前景。     

Application of an adsorption non-flow exergy function to an exergy analysis of a pressure swing adsorption cycle

Pressure swing adsorption (PSA) is a popular gas separation technology for the process industries and is commonly used for air separation, hydrogen purification, and isomer separation. In this study, we apply a second law analysis to this technology to identify sources of irreversibility in the process and, in particular, identify which steps in the PSA cycle are responsible for the major losses. Unlike previous exergy analyses, we derive and use expressions for the exergy of the adsorbed phase using adsorption thermodynamics. In this way, exergy loss (or entropy generation) within the adsorption cycle in each step is clearly identified. We illustrate the use of these exergy functions with the application of binary linear isotherm (BLI) theory to a four-step Skarstrom cycle. Major losses in the process are shown to be the exergy loss across the valve in the blowdown step, and feed compressor aftercooler losses. Feed repressurisation is shown to be more efficient than product repressurisation for the separation factor examined in this study since part of the feed gas is introduced at a low pressure. During the cycle, bed exergy loss during the feed step is significant, while there is no exergy loss in the adsorbent bed during the blowdown or purge steps. The exergy functions derived in this study can readily be applied to more complex PSA cycles and provide a basis for cycle design.     

小管道基准保温层厚度的提出及其计算

基于牛顿(Newton)冷却定律,推导出了圆形管道的热流损失数学模型,介绍了基于该模型的临界保温层半径的理论推导.并在此基础上,提出了一个全新的概念--"基准保温层厚度(δj)",即敷设保温层与不敷设保温层(裸管)热流损失相当时,对应的保温层厚度.推导得出了δj满足的数学方程,并基于计算程序得到了其数值解.其结果对工农...     

Effect of molecular orientation on the fracture toughness of thermoplastics

An account is given of fracture toughness experiments on injection moulded plaques of a propylene homopolymer and two different molecular weight grades of poly(methyl methacrylate). The study was concerned essentially with the behaviour of large, centrally notched, plaques since this represents a step towards component testing. However, in order to establish this point, small specimens machined from the plaques were also tested. Analysis of behaviour is by linear elastic fracture mechanics. The study showed that the fracture toughness parameter, K_IC, was not a material constant. Variations in fracture toughness are attributed to molecular orientation produced during the injection moulding process. As expected, the propylene homopolymer was tougher than the PMMA. However, a potentially ductile material can still fail in a brittle manner if a large enough specimen is tested. Overall, this study has emphasized that tests on complete mouldings can provide a valuable means of assessing potential practical performance, and also that data obtained on small specimens can be misleading with respect to the performance of large components.     

Enhanced shielding effectiveness of polymer matrix composite enclosures utilizing constraint‐based optimization

Many interrelated factors must be considered in the design of an electronic system. Finding the optimum design condition having been subjected to various design constraints is often not a trivial matter. Utilizing an approach to optimize the design of electronic systems would have many advantages. A design optimization approach allows designers to study and optimize the various design alternatives. To illustrate this approach, in this study the optimum design of electronic enclosures from the viewpoint of electromagnetic shielding effectiveness is considered. An optimization problem has been formulated and the influence of several design variables in the definition of the objective function and constraints set is examined. To solve the problem, a non‐linear optimization solution technique is utilized that allows users to optimize an objective function bound by equality and inequality constraints. A case study is presented to illustrate the utility of this technique in selection of the best composite materials for maximum absorption against radiated energy, a case with application in radar.     

Numerical Study of Two-Stage Horizontal Spray Dryers Using Computational Fluid Dynamics

This article presents the findings of a numerical simulation model of the spray-drying process in a two-stage horizontal chamber design with the aid of a computational fluid dynamic (CFD) model. The model describes heat, mass, and momentum transfer between two phases; namely, a continuous gas phase and a discrete phase of droplets (or particles), using the finite volume method. In this study, a new two-dimensional horizontal spray dryer (HSD) geometry is considered as a pilot study into the spray-drying process in this novel chamber configuration. The tested model is able to predict some important features of the spray-drying process, such as air flow patterns indicating recirculation zones and particle trajectory plots. Some performance parameters for spray drying, such as the rate of evaporation, average volumetric heat and mass transfer rates, etc., are calculated and discussed. This two-stage drying process especially applicable for the horizontal spray dryer (HSD) model is investigated and modeled. The bottom wall of the HSD is assumed to be a shallow fluid bed used for second stage drying. In this article, the fluid bed drying conditions are changed and compared. The drying within the fluid bed itself is not modeled in this study, however. It is shown that the particle residence time is higher when the fluid bed is included. The drying performance of this two-stage horizontal spray dryer is expected to be better than that of a single-stage dryer.     

生物质细粉加料技术的改进

在生物质快速热解的研究中,生物质细粉的稳定加料问题非常重要。通过对不同加料方式的加料特性对比,提出了适合生物质细粉的加料装置———旋流式气力输送加料器。研究表明,该加料装置具有连续稳定的特点,解决了生物质快速热解中小料率实验所要求的加料精度难题,且该加料装置也适合于其他粘性粉料(如细煤粉、超细粉)的连续均匀加料。     

几种秸秆醋液组分中活性物质的分析

以农作物秸秆(棉秆、稻秆、麦秆和玉米秆)为主要原料制备秸秆醋液,研究了在种炭化温度450、600和750℃下,棉秆醋液、稻秆醋液、麦秆醋液、玉米秆醋液的得率.研究表明秸秆醋液的得率随着炭化温度的升高而增加,当炭化温度为750℃时,醋液得率分别为棉秆醋液51.70%、玉米秆醋液45.2%、稻秆醋液4.91%、麦秆醋液42.44%.采用气-质联用仪进行秸秆醋液成分的分析,表明秸秆醋液是一种组分复杂的混合物,4种秸秆醋液平均含有24.41%酚类、22.09%的酮类、20.79%的有机酸、4.52%的醛类、4.20%的醇类及2.44%的酯类等.秸秆醋液中所含的乙酸、丙酸、苯酚、甲酚、甲氧基酚、乙醇等成分均为有效的活性物质,具有抑菌、杀菌的作用.