铝加工热轧机交流传动装置

简单介绍了用于热轧机主传动的大容量、高性能交流传动装置。重点对交-交变频传动,交-直-交三电平电压型PWM变频传动等几种主回路接线方案的技术特点进行了分析。     

全数字大功率交流变频调速装置在线材精轧机组上的应用

介绍一种电流源交－ 直－ 交变频器型全数字大功率交流变频调速装置在棒线材连轧生产线线材精轧机组主传动上的应用,说明其配置、功能、工作原理及特点。由于应用此种变频调速装置,简化了设计、安装及调试过程,提高了电气设备的控制性能及运行可靠性,保证了产品质量。     

大功率轧机交流调速技术的发展

介绍了当前大功率轧机主传动采用的交流调速系统概况以及交交变频,LCI交直交变频,IGCT/IGBT三电平PWM变频等交流调速系统等的特点;分析了轧机主传动机电振动的原因及抑制方法;最后阐明中国大功率轧机主传动交流调速系统的现状与发展.     

2400mm可逆铝带热轧机主传动方案选择

本文以2400mm可逆铝带热轧机主传动方案的制定为实例，从控制性能、动态响应、可靠性、节能效果、对电网污染程度及性能价格比几方面，详细分析了全数字直流传动系统、全数字交-交变频系统和基于IGCT的全数字交直交变频系统三个方案的优缺点，并结合有色金属加工企业的现状，论述了2400mm可逆铝带热轧机主传动方案制定过程。     

大功率轧机主电机电气传动方案的分析与比较

交流传动调速系统性能已经大大超过直流传动调速系统,交流传动技术在新建的轧机主传动中已经成为主导技术,交流传动系统又分为交 交传动和交 直 交传动两种传动方式,为此本文对交 交变频和交 直 交变频进行了深入的分析和比较,为大功率轧机主电机传动装置的设计选型提供参考。     

八钢中厚板轧机交—交变频主传动控制系统的特点

介绍了八钢3500 mm中厚板生产线的精轧机主电机交—交变频传动控制系统,其中包括交—交变频主回路的结构、西门子SIMADYN-D全数字64矢量控制交—交变频控制系统及其在中厚板轧机上的控制功能。     

国产大型热连轧机主传动交流调速系统

随着电力电子技术和矢量控制技术的发展,在工业产特别是在冶金行业中,交交流频同步电机矢量控制系统已经成为大型轧机主传动发展的必然趋势,结合攀钢１４５０热连轧主传动改造工程,对交流变频调速系统的原理,构成及调速性能指标等方面进行了分析与阐述。     

热带轧机主传动交-交变频与交-直-交变频调速系统的技术经济比较

以某工程热带轧机为例，对热带轧机主传动调速系统采用交-交变频调速和交-直一交变频调速的优缺点进行比较，总结出交-直-交变频调速系统将是今后热连轧机主传动变频调速系统的发展方向。     

交-交变频矢量控制系统在热连轧工艺中的应用

主要介绍了交-交变频全数字矢量控制系统的构成和控制原理以及在热连轧主传动中的应用.交-交变频全数字矢量控制系统作为交流调速系统的一种,被广泛的应用到主传动控制系统中.交-交变频调速系统并将随着时代的发展不断完善,逐步取代直流调速系统,成为电气传动领域中的主流.     

交-直-交变频调速系统在鞍钢大型厂50m重轨矫直机主传动辊上的应用

主要论述－直－交变频调速系统在鞍钢大型厂主传动辊上的应用,及其主回路系统和控制系统的工作原理,同时就大型厂矫直机的工艺流程作以介绍。     

钛渣酸解过程中物相变化特征探讨

明确物相变化是剖析钛渣酸解机理和改进酸解工艺的关键点之一.综合应用化学分析、X射线衍射(XRD)分析、矿物解离分析以及扫描电镜形貌分析对某74钛渣酸解过程中主要物相的含量、形貌变化以及Ti、Si两种元素的含量及赋存变化进行了研究.结果表明:钛渣主要由黑钛石和辉石组成,酸解过程中黑钛石含量逐渐减小,辉石含量逐渐增加;反应...     

Evaporation Research: Review and Interpretation

Literature regarding evaporation from soil, wet plant surfaces, and sprinkler droplets was examined, normalized, and interpreted. Much of the evaporation literature is difficult to compare and interpret; this paper offers comparisons and discussions of various findings by others as well as by the writers. Techniques of measuring and estimating evaporation from irrigation and rainfall are discussed. The partitioning between increased evaporation and decreased transpiration from a variety of research is quantified. Factors that impact the various forms of evaporation are listed and quantified. This review and summary will provide practitioners and researchers with theoretical and practical guidance on measurement techniques and estimates of evaporation under a wide range of conditions.     

Sham reasoning, Humpty Dumpty, and the burden of proof.

Slife and Reber ask of psychologists that they recognize their prejudice against theism and the incompatibility between theistic and naturalistic worldviews. Yet, the subtext of their article is that theism and naturalism are equally valid and that psychology’s secularism is a mistake. Given that theism is not beyond reason, the only sufficient ground for charging psychologists with prejudice is if (i) theism has survived serious attempts at conceptual and empirical test, and (ii) psychology ignores or disguises this fact. So, the grounds for believing in the reality of a supernatural existent are highly relevant to the authors’ allegation. However, their concept of God affords no such grounds. They disavow the logic involved in the ordinary meaning of the term “incompatible” and they ignore a crucial distinction between conditions of existence and qualities of things or processes. The consequence is that either God is this-worldly, and there is no ontological basis to Slife and Reber’s incompatibility thesis, or God’s mode of existence is quite different from the mode of existence of ordinary things and all the problems of dualism follow. Either way, their charge of prejudice is without foundation. The burden of proof rests with the defender of theism and, for now, psychology’s secularism can be considered a mark of the discipline’s (sometimes questionable) rationality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Observed & experiential integration (OEI): Discovery and development of a new set of trauma therapy techniques.

Psychotherapy integration leaders have recently asserted that the future of psychotherapy will involve incorporation of neuroscience. In the past 18 years, techniques have been discovered and developed to treat trauma and dissociation at all three neurobiological levels of Porges' (2001, 2007) polyvagal theory. This approach is known as Observed & Experiential Integration (OEI). The originator incorporated elements of Focusing, Eye Movement Desensitization and Reprocessing, and Educational Kinesiology. OEI theory emerged from experiential psychotherapy, and relational psychoanalytic and behavioral concepts were assimilated during 45,000 hours of psychotherapy. Five sets of OEI techniques are used for titration of affective and somatic intensity, reduction of negative transference, and deepening of social connection. OEI involves neuro-activation & microattunement (NAMA). It has been applied with body therapies and neurotherapy and used with children, couples, and families. OEI has also been applied to addictive and self-destructive urges, panic attacks, and eating disorders. Case examples illustrate applications of this treatment. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Contractor Performance Prediction Model for the United Kingdom Construction Contractor: Study of Logistic Regression Approach

An accurate prediction of contractor potential is of vital importance during contractor selection and evaluation process. Such prediction enables identification and classification of contractor performance to ease the selection process. This paper outlines the use of clients' tender evaluation preferences for predicting a contractor performance via a logistic regression (LR) approach. A total of 31 clients’ tender evaluation criteria were selected to develop a LR model for predicting contractor performance. The proposed model was developed based on 48 of United Kingdom public and private construction projects and validated in 20 independent cases. It was found that 75% of the cases correctly and the model statistically accurate for contractor performance prediction, where the input variables consist of nominal and interval data. The paper summarized techniques and advantages of LR analysis and discussed literature findings of contractor selection and evaluation methodologies undertaken by construction researchers and commentators from the United Kingdom and Northern America.     

Design Error Classification, Causation, and Prevention in Construction Engineering

Construction and engineering practitioners have found it increasingly difficult to learn from their mistakes, particularly with regard to the prevention, identification and/or containment of design errors. Yet, design errors have been the root cause of numerous catastrophic accidents that have resulted in the death and injury of workers and members of the public. This paper examines and classifies the nature of error and design error causation in construction and engineering projects. A review of the normative literature revealed that design errors are caused by an array of factors that can work interdependently. A generic framework is developed that classifies design error according to people, the organization, and project is presented. The paper suggests that people, over and above organizational and project management strategies, have the greatest propensity to reduce errors through the process of situated learning and knowing. This is because the working environment provided by an organization and the processes used to deliver construction and engineering projects influence the nature and ability of people to undertake tasks. Consequently, there is no single but rather a multitude of strategies that need to be adopted in congruence to reduce design errors so that safety and project performance are ameliorated.     

Comparison of Arsenate, Lead, and Cadmium Adsorption onto Aged Biofilter Media

Many biological water treatment plants for removal of iron and manganese from groundwater are in place for quite a long time, and thus their filters are aged—naturally coated with metal oxides and associated biomass. The particular reactivity and high adsorption capacity of these biogenic surface coatings make them potentially applicable for cost effective removal of arsenic and other heavy metals from contaminated water. However, the nature of interaction between various toxic elements and the composite materials in biological filters is not well understood. This study combines macroadsorption experiments with electron probe analysis to evaluate the adsorption properties of the biogenic surface coatings of an aged biofilter medium (BFM) for cationic lead and cadmium as well as arsenate anion. Results of batch adsorption showed that BFM has higher adsorption capacity for lead and cadmium as compared to arsenate anion. At pH 5.5, the maximum adsorption capacities of the medium for As(V), Pb(II), and Cd(II) were 17.03-, 80.77-, and 179.05-mg/g surface coatings, respectively. However, the column performance of BFM for Cd(II) was rather low. In particular, the breakthrough adsorption capacities (qb) of the BFM for As(V), Pb(II), and Cd(II) were 0.247-, 31.168-, and 4.084-mg/g surface coatings, respectively. These values represent about 1.5, 38.6, and 2.3% of the respective theoretical maximum adsorption capacities (qmax) of BFM for these metals. Data from the X-ray electron probe analysis corroborated well with that of the macroadsorption experiments. Results of this study strongly suggest that the Mn/Fe ratio and the presence of preadsorbed competing ions were two of the principal characteristics of the BFM, governing its affinity and adsorption capacity for different toxic metals.     

Management of Fluid Mud in Estuaries, Bays, and Lakes. II: Measurement, Modeling, and Management

Techniques for measurement, modeling, and management of fluid mud are available, but research is needed to improve them. Fluid mud can be difficult to detect, measure, or sample, which has led to new instruments and new ways of using existing instruments. Multifrequency acoustic fathometers sense neither density nor viscosity and are, therefore, unreliable in measuring fluid mud. Nuclear density probes, towed sleds, seismic, and drop probes equipped with density meters offer the potential for accurate measurements. Numerical modeling of fluid mud requires solving governing equations for flow velocity, density, pressure, salinity, water surface, plus sediment submodels. A number of such models exist in one-, two-, and three-dimensional form, but they rely on empirical relationships that require substantial site-specific validation to observations. Management of fluid mud techniques can be classified as those that accomplish: Source control, formation control, and removal. Nautical depth, a fourth category, defines the channel bottom as a specific fluid mud density or alternative parameter as safe for navigation. Source control includes watershed management measures to keep fine sediment out of waterways and in-water measures such as structures and traps. Formation control methods include streamlined channels and structures plus other measures to reduce flocculation and structures that train currents. Removal methods include the traditional dredging and transport of dredged material plus agitation that contributes to formation control and/or nautical depth. Conditioning of fluid mud by dredging and aerating offers the possibility of improved navigability. Two examples—the Atchafalaya Bar Channel and Savannah Harbor—illustrate the use of measurements and management of fluid mud.     

"Clinical child psychology: A practice specialty serving children, adolescents, and their families": Correction to Jackson et al (2010).

Reports an error in "Clinical child psychology: A practice specialty serving children, adolescents, and their families" by Yo Jackson, Fred L. Alberts Jr. and Michael C. Roberts (Professional Psychology: Research and Practice, 2010[Feb], Vol 41[1], 75-81). The following sentence on page 79 is incorrect: “As evidence of the growing recognition of board certification, many institutions providing services to children, adolescents, and families are requiring their psychologists to become certified by ABPP (e.g., Mayo Clinic) and some insurance companies now mandate this for their panels (e.g., Group Health in Seattle).” In fact Group Health in Seattle does not mandate ABPP certification for psychologists. The sentence should not contain the example in the second set of parentheses. (The following abstract of the original article appeared in record 2010-02467-010.) Clinical child psychology is a growing and vibrant field of practice and research within professional psychology. The purpose of this article is to contribute to the recent series of articles on specialties in Professional Psychology Research and Practice and delineate the development, design, and purpose of clinical child psychology. The article describes the current trends in the specialty and the challenges clinical child psychologists face in tending to the mental health needs of youth and their families. The need for the specialty and the definition of the scope of the work of clinical child psychologists is described. The parameters of training are also discussed, with a focus on the distinctiveness of the role of the clinical child psychologist. Outlined are applications of the work with children, adolescents, and their families including types of professional practice and collaborations with other professionals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)