用煤粉代替焦粉的烧结实践

广钢的烧结燃料是焦粉,燃料成本偏高。为降低燃料成本,决定用价格较低的无烟煤粉代替焦粉,在烧结杯实验的基础上,进行了生产试验,取得了降低烧结燃料成本的成效。研究与实践表明,煤粉配入比例占燃料的40%左右比较合适。     

煤的气化及其发展

钢铁企业的能源结构和燃料经济是一个关系到钢铁工业发展速度和国家燃料资源合理利用的技术、政策性很强的问题。多年以来,我国有不少企业的燃料供应处于“来什么用什么”的浮动状态,由于燃料品种变化频繁、质量低劣、以及燃料加工、利用技术的落后所造成的设备寿命低、产品质量差和消耗指标高的情况是有目共睹的。世界各主要产钢国家之所以取得高速发展和优质低耗的先进指标,而燃料经济的科学管理和对燃料质量的严格要求是主要原因之一。在实现我国钢铁工业现代化的过程中,必须把燃料供应和利用的问题提到足够的高度,只有尽快对企业的燃料构成以及燃料品种、质量的技术标准作出合理的选择,才能适应形势发展的要求。     

各种因素对喷吹置换比影响的分析

高炉喷吹燃料的中心环节是保证在一定喷吹量条件下,努力提高置换比,大力降低综合燃料比。不管喷吹何种燃料,置换比越高,则节能、降焦和经济效益越显著。因此进一步分析提高喷吹燃料的置换比是高炉工作者的迫切任务。置换比的高低除与喷吹燃料本身理化性质有关外,还与入炉原燃料质量、风温、富氧水平、喷吹燃料粒度和雾化程度、风口区     

固(液)体燃料发热量的简易计算

发热量是燃料的重要指标。评定燃料的性质和使用价值、选择燃烧方法和燃烧装置、计算炉窑的热工参数和热平衡等,都需要首先知道燃料的发热量。固此,关于燃料发热量的计算一直是燃料化学和热工学中研究的问题,尤其以煤发热量的计算最为突出。     

SHS燃烧化学

传统供热燃烧是利用燃料和氧化剂的反应获得热能。自蔓延高温合成(SHS)则是利用燃料和氧化剂的放热反应制备有用材料。根据SHS的燃料和氧化剂的种类,SHS的反应体系可分为两类:元素间的直接合成;以化合物为反应物的合成。前者,在绝大多数情况下,金属元素是燃料,非金属元素是氧化剂,属无氧燃烧。后者,燃料是金属或低价氧化物,氧化剂是氧化物、过氧化物、气体氧或非金属。文中讨论了燃烧中的化学反应、反应机制和产物。     

LPG辐射管燃烧炉改用LNG的技术经济性分析

分析了LPG和LNG燃料在辐射管燃烧炉上的燃烧特性、CO2排放特性,讨论了更换燃料后必须考虑的技术问题及改进措施,同时对燃用两种燃料的经济性进行了对比。分析表明:LNG燃料可满足LPG辐射炉燃烧工况,具有可观的CO2减排能力,同时可降低企业燃料成本,是一种在技术性和经济性上都非常合适的替代燃料。     

固体生物质燃料产业发展的核心问题

固体生物质燃料是一种高效的清洁能源,可以替代化石燃料,缓解人类面临的能源危机和环境困境.在调研的基础上对固体生物质燃料产业存在的问题进行提炼和总结,找出阻碍固体生物质燃料产业链各子系统发展的核心问题.分析这些问题可为制订推进固体生物质燃料产业发展的政策方案提供事实依据和设计思路.     

阳极焙烧炉工艺管理节能优化分析

阳极焙烧炉的燃料消耗是阳极焙烧的一项重要指标,焙烧炉的燃料消耗取决于多种因素,合理的燃烧工艺管理操作方法是减少燃料消耗的一个重要环节.本文从阳极焙烧炉热平衡分析入手,通过分析找出影响燃料消耗的影响因素与燃烧消耗之间的关系并根据工作实践提出阳极焙烧工艺管理节能优化的措施.     

高炉喷吹煤和废塑料混合燃料燃烧过程的数值模拟

采用数学模型预测高炉喷吹煤与废塑料混合燃料在直吹管的燃烧过程,数学模型包括气相流动、混合燃料的燃烧、辐射传热等子模型.模拟结果表明,燃料总的燃烧效率能达到90%以上,高炉喷吹煤与废塑料混合燃料在高炉的燃烧行为介于高炉单独喷吹煤粉和废塑料两者之间,高炉喷吹煤与废塑料混合燃料在理论上是切实可行的.     

气体燃料的有效使用

人们都希望尽可能有效地使用燃料。但有关燃料和燃烧的一些基本概念却往往被人们忽略或误解。 燃料是什么?燃料即是能被氧化且迅速释放出热量的物质。热量释放太快,即为爆炸;太慢,对金属即称为锈蚀。 燃料的燃烧和爆炸是由其物理状态所决定的。氧化单位重量的某物质所释放的能量     

Modeling Fate and Transport of Roadside-Applied Herbicides

A physically based, one-dimensional, mathematical model is developed to simulate transport of herbicides applied to roadsides into adjacent surface water. Herbicide transport by overland flow, infiltrating water, and subsurface flow is considered. The model accounts for advection, dispersion, equilibrium linear sorption in the soil, and first-order decay of the herbicides. Chemical transport between soil and overland flow is described using a rate-limited mass exchange between the two compartments that is proportional to the difference between the chemical concentration in overland flow and the pore water with a proportionality constant that is a function of overland flow characteristics and rain intensity. For simulating overland and subsurface flow, the kinematic wave equation is solved using a Crank–Nicolson finite difference scheme. Richards’ equation is solved using a Galerkin finite element method to model infiltration, and the transport equation is solved using a finite difference method. The model is calibrated and verified using extensive field data on the runoff of five herbicides with a range of physical–chemical properties at two field sites. Good agreement is obtained between predicted and measured event-mean concentrations in runoff and the herbicide concentration remaining in the application-zone soil.     

Industrial Psychology as an Academic Discipline.

The potential conflict for the industrial psychologist in a liberal arts setting is that in one role he is on the side of theory, broad social concern, and contributions to the liberal education of his students, and in the other role, on the side of practical techniques for getting things done, concern for a more limited sector of society, and vocational preparations of his students. This paper is a personal effort to clarify a personal conviction that such conflict is unreal and unnecessary. While industrial psychology is indeed a professional field of practical endeavor, and while it does in fact offer much that is useful to managers and administrators, it is also a broadly significant body of knowledge that intrinsically deserves to grow. In short, it is the author's conviction that industrial psychology is or can become an academic discipline occupying a rightful place within the liberal arts setting of Academia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bayesian Model Calibration Using Geotechnical Centrifuge Tests

The predicted performance using a geotechnical prediction model is expected to deviate from reality. A practical approach to assess the model error is through calibration with observed performances in physical model tests. In this paper, a Bayesian framework of model calibration using centrifuge modeling tests is proposed and the procedure of model calibration is illustrated. Two centrifuge tests conducted to investigate the performance of soil slopes under rainfall conditions are used to calibrate a coupled hydromechanical analysis model. It is found that for centrifuge tests with different levels of soil variability, the test with a smaller variability of soil properties is more efficient for model calibration. According to the concept of random field, a centrifuge model with a larger model size and accelerated to a lower acceleration is better for model calibration. When the discrepancy between the performance interpreted from the centrifuge model and the field performance is small, the improvement of the reliability estimation for a new slope is significant. However, when there is little information about the discrepancy, the reliability estimation cannot be significantly improved by the information from centrifuge modeling. The proposed procedure is shown to be able to quantify the calibration effects of centrifuge tests and may be used to achieve a more reliable calibration.     

Bayesian Updating of Structural Models and Reliability using Markov Chain Monte Carlo Simulation

In a full Bayesian probabilistic framework for “robust” system identification, structural response predictions and performance reliability are updated using structural test data D by considering the predictions of a whole set of possible structural models that are weighted by their updated probability. This involves integrating h(θ)p(θ∣D) over the whole parameter space, where θ is a parameter vector defining each model within the set of possible models of the structure, h(θ) is a model prediction of a response quantity of interest, and p(θ∣D) is the updated probability density for θ, which provides a measure of how plausible each model is given the data D. The evaluation of this integral is difficult because the dimension of the parameter space is usually too large for direct numerical integration and p(θ∣D) is concentrated in a small region in the parameter space and only known up to a scaling constant. An adaptive Markov chain Monte Carlo simulation approach is proposed to evaluate the desired integral that is based on the Metropolis-Hastings algorithm and a concept similar to simulated annealing. By carrying out a series of Markov chain simulations with limiting stationary distributions equal to a sequence of intermediate probability densities that converge on p(θ∣D), the region of concentration of p(θ∣D) is gradually portrayed. The Markov chain samples are used to estimate the desired integral by statistical averaging. The method is illustrated using simulated dynamic test data to update the robust response variance and reliability of a moment-resisting frame for two cases: one where the model is only locally identifiable based on the data and the other where it is unidentifiable.     

Model for the Force–Displacement Relationship of Wire Rope Springs

A mathematical model for the restoring force of the wire rope spring is presented. The model is semianalytical in nature and is fully defined by the dimensions and properties of the spring. Emphasis is placed on the tension-compression mode of deformation. An experimental investigation is described in which the force–displacement relationships, for a number of springs, were obtained. For modeling purposes, the restoring force is decomposed into an elastic force and a damping force. The elastic force is modeled by a geometric nonlinear finite beam element. The equivalent cross section is calculated assuming full slip among the individual wires and strands. The damping force is modeled by a constant and a displacement-dependent forces. Based on energy dissipation equivalence, an empirical expression for the damping force is developed.     

Review of Divorced families: A multidisciplinary developmental view.

Review of Divorced families: A multidisciplinary developmental view (see record 1987-97107-000). This book is intended to provide all professionals working in the context of family issues and transitions with the beginnings of a model of the normal processes of divorce. As such, it is of interest to sociologists, policy makers, lawyers, mediators, researchers, and clinicians such as psychologists and social workers, in fact anyone who is interested in the changing face of the North American family. In general, this is a satisfying and inspiring work. It is comprehensive, covers a difficult and complex area in a systematic and integrated fashion, and suggests a positive health-promoting role for professionals in this field. It is above all highly relevant to a wide range of professionals, in that the process of divorce is viewed as a sociological fact, a personal stressful experience, a crisis of family restructuring, and a phenomenon calling for more empirical research and theoretical model building. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Generalized Continuum Theory and Its Relation to Micromorphic Theory

Classic continuum mechanics views a crystal as a homogeneous and continuous medium, in which the basic structural unit of the crystal is taken without structure and is idealized as point mass. Micromorphic theory views a material as a continuous collection of deformable point particles; each particle has finite size and additional nine internal degrees of freedom describing the stretches and rotations of the particle. This paper presents a multiscale field theory that views a crystalline material as a continuous collection of lattice points, while embedded within each point is a group of discrete atoms. The atomistic formulation of the field theory is briefly introduced. Its relation with the well-known micromorphic theory is derived. The applicability of the classical continuum theory, micromorphic theory, and the generalized continuum field theory is discussed.     

Maximization of Water Storage in Backfilled and Lined Channels and Dimples Subject to Evaporation and Leakage

A channel or axisymmetric dimple filled with a coarse porous material and aimed at a temporary storage of infiltrated water as a perched water table aquifer is studied. The bottom shape is varied based on the criterion of maximal water storage after a certain period of drainage and evaporation. Leakage into the vadose zone through a thin liner occurs with a specific discharge proportional to the pressure drop across the liner. Evaporation through a horizontal shrinking water table is spatially uniform. An ordinary differential equation, which follows from the mass balance condition, is solved either explicitly or numerically. The class of triangular, polynomial, and conical sections is studied. The shape of maximal water retention is calculated for a given initial stored water volume or water table width, evaporation intensity, liner thickness and conductivity, vadose zone pressure beneath the liner, and selected time interval between two sequential infiltration events.     

Oscillation Susceptibility Analysis along the Path of the Longitudinal Flight Equilibriums in ADMIRE Model

Our goal is the oscillation susceptibility analysis in the framework of a nonlinear mathematical model in the so-called ADMIRE or Aero Data Model in a Research Environment. First, we analyze the oscillation susceptibility along the path of the longitudinal flight equilibriums when the flight control system (FCS) is decoupled. After that, a similar analysis is undertaken in the case when the FCS is coupled. For decoupled FCS, it is shown that on the path of the longitudinal flight equilibriums there exists a saddle-node where stability is lost and fold bifurcation occurs. Maneuvers are simulated showing the effect of an instantaneous change of the elevator angle, and the evolution of the unstable equilibriums (due to the maneuvers) to the corresponding exponentially stable equilibriums. It is shown numerically that at the saddle-node oscillations occur when the elevator angle is less than the critical value and the start is from the saddle-node. More precisely, it is shown that if the plane state parameters coincide with the saddle-node coordinates and the elevator angle is changed instantaneously from the critical value to a value which is less than this value, then two of the state parameters (α,q) begin to oscillate with the same period and the third parameter (θ) increases, tending to infinity. Thus, the orbit of the system evolves spiraling. It is shown also, that if the elevator angle is reset, the plane returns to a stable equilibrium. Therefore, a soft or no catastrophic stability loss takes place. When the FCS is coupled, the plane for every value of the amplification factor has a unique equilibrium which is exponentially stable and attracts all the equilibriums which exist in decoupled case. In this case, there are no bifurcation points on the equilibrium path. The dependence of the equilibrium and of the relaxation period on the amplification factor value is found numerically. Finally, it is concluded that when the FCS is decoupled, then along the path of the longitudinal equilibriums oscillations can occur, but when the FCS is coupled and the pilot can modify (instantaneously) only the amplifier factor value, then the vehicle, defined by the considered numerical data, is not anymore susceptible to oscillation.     

Vulnerability-Based Risk Assessment for Stream Instability at Bridges

The Federal Highway Administration recommends that stream stability analyses at bridges over water begin with a Level 1 assessment. Following this assessment of the physical condition of the stream in the vicinity of the bridge, the user must determine whether or not the relative risk is low. If it is low, then no action is needed. If the risk is greater than low, then a Level 2 analysis is recommended; however, no method is given for determining the risk. In this paper, the relative risk of unsatisfactory conditions at bridge foundations is assessed as a simple function of vulnerability and criticality. Vulnerability is based on a stream stability assessment and data from the National Bridge Inventory (NBI). Criticality is determined indirectly as a function of the bridge serviceability and cost by using data extracted from the NBI. Relative risk is then qualitatively determined by combining vulnerability and criticality. Three examples in central Pennsylvania are provided in which the relative level of risk is used to determine the need for a Level 2 analysis.