熄焦塔内喷洒系统的研究

通过对熄焦喷嘴、焦炭在熄焦车内分布的研究,确定最佳结构的喷嘴以及喷洒角度,确保熄焦有效,减少熄焦时间.     

低水熄焦技术在焦化厂的应用

采用了低水熄焦技术，解决了喷嘴堵塞以及喷洒不均匀的问题。熄焦时间缩短了30～35s，焦炭水分降低了1％左右，减少了熄焦用水用电量。     

冶金新技术20行

转炉炉衬的火焰喷补新工艺苏联日丹诺夫伊里奇钢铁厂为进一步提高氧气炼钢转炉的炉龄,研制成功了一种新的热喷补工艺,称之为涡流-火焰喷补工艺。为了改进喷补料的性能使之能牢固的与炉衬熔接在一起,而采用了以镁粉为主并加入了一定量的焦炭的喷补料。将粉碎后的熊炭加入到喷补料中,可以大大减轻采用风动法输送喷补料时的困难.经测定,焦炭颗粒在1400℃下的发火时间为0.3s,超过了它由喷嘴喷射到炉衬的时间,焦炭颗粒被喷射到炉衬表面后,在氧气流中及在与镁粉的直接接触中燃烧,从而可将镁粉颗粒迅速加热到塑性状态,使之能和炉衬表面牢固地熔接在一起而形成喷补层.焦炭颗粒在燃烧后所形成的燃烧层可提高炉衬喷补层的气孔率.该厂为提高喷补效率而采用了     

挥发窑处理含锌浸出渣挥发率及工艺节能探究

本文详细的阐述了挥发窑处理含锌浸出渣的基本理论和原理,物料的反应机理、工艺流程,讨论反应带温度、反应带长度、料层内气氛等对锌及其他有价金属挥发率与窑况的影响.通过改进工艺和强制鼓风管喷嘴形状,调整风压,强化配料,选择适宜的焦炭粒度,稳定窑况,使挥发窑稳定经济的运行.     

2000m3高炉焦炭质量评价

 由于目前还没有一个能综合反映焦炭质量的指标,因此从影响高炉焦比的角度出发,选取了焦炭灰分、硫分,以及M40,M10,CRI,CSR这6个指标并赋予不同的权重对焦炭质量进行评价。从焦炭质量指标、高炉技术经济指标和统计观点阐述了2000m3高炉用焦炭质量的评价方法。首次提出焦炭评分制,并建立了焦炭质量评价模型。同时加入焦炭预估价格、价格差和性价比等参数辅助评价焦炭质量。通过对8种焦炭进行模型验证,结果显示各焦炭质量差异明显,通过对高炉各焦炭配比进行优化之后,炉况运行稳定,焦炭成本降低。     

焦炭反应性和反应后强度的关系及影响因素研究

为了预测焦炭在高炉中的反应行为,对莱钢大量的焦炭进行了检测及数据的分析,说明焦炭反应性与反应后强度之间有良好的负相关性;对焦炭冷态强度与热态性能之间进行了对比,建议企业在保证焦炭的冷态强度合格的同时更要关注焦炭的热态性能指标;对影响焦炭热性能指标的水分、熄焦方式及配煤结构等因素进行了试验研究,指出焦炭水分稳定在较低水平上可以提高焦炭的热性能;干法熄焦可以显著改善焦炭的热性能;验证了配煤结构及煤质性能对焦炭热性能有根本影响。     

ZnO对焦炭与CO2反应的影响

摘要：锌作为有害元素,在高炉内循环富集给生产带来了一系列不利影响。采用醋酸锌水溶液浸泡法向焦炭中添加ZnO,研究了ZnO对焦炭与CO2反应的影响,采用3D光学数码显微镜对焦炭进行了微观观察,并对反应后焦炭表面形成物进行了XRD分析。结果表明,ZnO对焦炭与CO2反应有一定的催化作用,但焦炭表面的ZnO含量过高会降低其催化作用,其主要原因是ZnO和焦炭灰分中的SiO2很容易形成Zn2SiO4,并会在焦炭表面形成一层壳状物,堵塞焦炭气孔,阻碍焦炭与CO2的进一步反应。此外,锌蒸气较CO2更容易进入焦炭内部,并在其中发生还原与氧化循环反应,对焦炭内部结构造成破坏,从而影响焦炭反应后强度。     

日本采用硬度测定方法评价焦炭强度

最近,日本根据焦炭颗粒破坏接触理论建立的力学模型,对焦炭在高炉内和转鼓强度试验时的机械粉化行为,尤其是焦炭反应后粉化行为进行了解析和推算。在这一研究中,作为影响焦炭粉化发生量的机械特性是焦炭的抗压强度。关于焦炭的抗压强度,住友金属工业公司测定了焦炭的布氏硬度。     

添加无烟煤对焦炭微晶和气孔结构的影响

根据焦炭的XRD谱图及SCHERRER'S 公式研究了添加无烟煤炼焦后焦炭的微晶结构参数的变化.试验结果表明:添加无烟煤可以促进焦炭中微晶的发展,使焦炭微晶结构参数La、Lc和石墨化度增大.利用氮气吸附方法分析了焦炭气孔结构的变化,结果发现:添加无烟煤炼焦后焦炭的微孔体积、比表面积和平均孔径都有显著的降低.根据FHH模型计算了焦炭的分形维数.结果表明:在焦炭中存在分形结构,添加无烟煤炼焦后焦炭的分形维数降低,焦炭表面变光滑.     

高炉焦炭石墨化过程中的微观组织和冶金性能演变

当前低碳高炉冶炼条件下使得炉内焦炭层变薄,恶化了料柱的透气透液性,焦炭在炉缸高温区石墨化过程中产生的焦粉是导致该现象出现的主要原因之一.为了研究焦炭在高炉下部的石墨化过程对其在炉缸内的冶金性能影响,研究了1100~1500℃不同温度下焦炭的石墨化度改变;同种焦炭石墨化程度与焦炭反应性及反应后强度之间的关系;不同石墨化度焦炭与碱金属侵蚀之间的关系;观察并分析了试验后不同焦炭试样的微观形貌.结果表明,随着温度的升高,焦炭石墨化程度加深,且温度每升高100℃,焦炭石墨化度约提高1.8倍,层间距d₀₀₂值约降低2%,微晶结构层片直径L_a值约提高3%,层片堆积高度L_c值约提高15%;焦炭的表面气孔减少,特别是大气孔减少,焦炭表面镶嵌组织减少,各向同性组织增多,焦炭的结构有序化程度增强.随着焦炭石墨化程度的加深,焦炭的反应性逐渐减小、反应后强度逐渐提高,焦炭表面的劣化情况减弱,生成的大气孔减少,气孔壁破坏趋势减弱.碱金属对焦炭的反应性有促进作用,使焦炭的反应性提高,反应后强度降低.而焦炭的石墨化对焦炭的碱侵害具有一定的抵抗作用,降低了焦炭表面的劣化程度.      

New Orleans Levee System Performance during Hurricane Katrina: London Avenue and Orleans Canal South

Hurricane Katrina was one of the worst natural disasters in U.S. history. The effects of the hurricane were particularly devastating in the city of New Orleans. Most of the damage was due to the failure of the levee system that surrounds the city to protect it from flooding. This paper presents the results of centrifuge models conducted at Rensselaer Polytechnic Institute and the U.S. Army Corps of Engineers simulating the behavior of the levees at London Avenue North and South that failed during Hurricane Katrina. Those levees failed without being overtopped by the storm surge. Also included are the results of a centrifuge model of one levee section at Orleans Canal South, which did not fail during the hurricane. The key factor of the failure mechanism of the London Avenue levees was the formation of a gap between the flooded side of the levee and the sheetpile. This gap triggered a reduction of the strength at the foundation of the protected side of the levee. The results are fully consistent with field observations.     

Lessons Learned from Failures of the Building Envelope in Windstorms

Lessons learned from failures of the building envelope in windstorms are encapsulated in three principal findings. The building envelope is crucial to the performance of buildings in windstorms. Windborne debris is decisive in shaping the performance of the building envelope. Design attention should be given to postimpact behavior of building-envelope systems. Reviews of damage documentation, insurance records, and computer simulations of building failures establish the importance of the building envelope to satisfactory building performance. These reviews also establish the decisive role of windborne debris in causing damage. The imperative for considering the postimpact behavior of building envelope systems is discussed, and innovative glazing products that meet new design criteria are presented. It is concluded that the building envelope should be given status equal to the principal structural frame in terms of design attention.     

Addition of Cobalt to Lead Anodes Used for Oxygen Evolution—A Literature Review

A review of the literature dealing with the effect of cobalt on lead-based anodes for oxygen evolution during electrolysis of sulfuric acid solutions verifies that the presence of cobalt at the anode–electrolyte interface, either as constituent of the anode material or as ions in the electrolyte, catalyzes the evolution of oxygen and reduces the corrosion of the anodes and the contamination by lead of metal cathodes produced during electrowinning. However, due to harmful effects of cobalt ions on the cathodic reaction in some processes, these benefits are limited to the electrowinning of copper. Efforts to develop a way of introducing cobalt at the anode–electrolyte interface without interfering with the cathodic reactions are reviewed in this paper. The use of lead–cobalt alloy anodes has had limited success due to issues arising from the low solubility of cobalt in lead, segregation during casting of the alloys, and nonuniform distribution of cobalt which affects the integrity of the anodes. This has been overcome in part lately by inclusion of cobalt into only the surface layer of a lead or lead alloy substrate, by thermal treatment of a cobalt salt to form a catalytic cobalt oxide surface species, or by electrodeposition of composite lead–cobalt oxide anodes. The last approach in particular has been actively investigated by several groups, but to our knowledge it is yet to find application in the industry. The review also critically examines the likely reaction mechanisms involved.     

Creep Modeling in Excavation Analysis of a High Rock Slope

Based on the distinct element method, a numerical procedure is presented for simulation of creep behavior of jointed rock slopes due to excavation unloading. The Kelvin model is used to simulate viscous deformation of joints. A numerical scheme is introduced to create incremental contact forces, which are equivalent to producing creep deformation of a rock-joint system. The corresponding displacement of discrete blocks due to creep deformation of contact joints can be calculated by equilibrium iteration. Comparisons of results between the numerical model and theoretical solutions of a benchmark example show that the presented model has excellent accuracy for analysis of creep deformation of rock-joint structures. As an application of the model, residual deformations of the high rock slopes of the Three Gorges shiplock due to excavation unloading and creep behavior are investigated. By simulating the actual excavation process, the deformation history of a shiplock slope is studied. Good agreement has been achieved between numerical prediction and field measurements. It demonstrates the effectiveness of the presented model in analysis of the creep deformation due to excavation unloading of high rock slopes.     

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)     

Cropland Measurement Using Thematic Mapper Data and Radiometric Model

To halt erosion and desertification, it is necessary to quantify resources that are affected. Necessary information includes inventory of croplands and desert areas as they change over time. Several studies indicate the value of remote sensor data as input to inventories. In this study, the radiometric modeling of spectral characteristics of soil and vegetation provides the theoretical basis for the remote sensing approach. Use of Landsat Thematic Mapper images allows measurement of croplands in Saudi Arabia, demonstrating the capability of the approach. The inventory techniques and remote sensing approach presented are potentially useful in developing countries.     

Reliability-Based Design for External Stability of Mechanically Stabilized Earth Walls

A two-phase approach was used to develop a reliability-based design (RBD) method for external stability of mechanically stabilized earth (MSE) walls. In the first phase, a parametric study was conducted using Monte Carlo simulation to identify parameters that affect the probability of external failure of MSE walls. Three modes of failure were considered: sliding, overturning, and bearing capacity. External stability was assessed by treating the reinforced soil as a rigid mass using the same procedures employed for conventional gravity-type wall systems. Results from the parametric study indicate that the mean and coefficient of variation of the backfill friction angle are significant for sliding, the mean and coefficient of variation of the friction angle of the backfill and coefficient of variation of the unit weight of the backfill are significant for overturning, and the mean and coefficient of variation of the friction angle of the foundation soil and the mean of the backfill friction angle are significant for bearing capacity. In the second phase, a series of additional simulations was conducted where the significant parameters identified in the parametric study were varied over a broad range. Results of these simulations were used to develop a set of RBD charts for external stability of MSE walls. A comparison indicates that similar reinforcement lengths are obtained using RBD and conventional methods and that the inherent probability of external failure in conventional deterministic design is ? 0.001. This probability of external failure is similar to inherent probability of failure reported by other investigators for similar geotechnical structures.     

Characteristics of Contractor’s Liabilities for Defects and Defective Work in Korean Public Projects

Modern buildings and civil structures are complex undertakings and involve the use of a great variety of engineering methods and processes. Therefore most projects face the possibility of defects and defective work, which generally result in structures that cannot perform their originally intended roles. The characteristics of the contractor’s liabilities for defects are very controversial in Korea. There are two conflicting theories and one compromise between the two, concerning defect liabilities. One is liability in terms of the law, and the other is that in terms of the contract. These two kinds of liability are significantly different, varying in definition, scope of responsibility, period of responsibility, and other aspects. The purpose of this study is to suggest how to resolve potential disputes which might result from these differences through the analysis of current laws and their interpretation.     

Approach to Separate Sand from Gravel for Bed-Load Transport Calculations in Streams with Bimodal Sediment

The bed material found in gravel-bed streams is nonuniform in terms of grain size and can typically be classified as unimodal or bimodal. The latter type of sediment distribution is usually represented by two modes, one of sand size and another of gravel. For this case, the movement of one mode becomes nonlinearly influenced by the other. As a result, the presence of the two modes in a bimodal material complicates the calculation of bed-load transport rates. The present study proposes an approach to separate the calculation of bed-load transport rates for bimodal materials into two independent fractions of sand and gravel, thereby rendering the bed sediment into two unimodal components. This approach is accomplished by decoupling the two fractions through scaling the reference Shields stresses of the sand and gravel modes to match the value of the mode of unimodal materials. Consequently, the contribution of each fraction to bed load can be estimated using a suitable relation derived for unimodal materials. Laboratory and field bed-load data available in the literature are used to examine the validity of the overall approach.     

Methodology for Automating the Identification and Localization of Construction Components on Industrial Projects

Even though engineered components, such as pipe spools and structural steel elements, generally account for a significant percentage of the total installed cost of an industrial project, current industry practices still rely on human ability to track thousands of these components individually after they are received at the job site. These site-tracking practices are inefficient and error prone. This paper presents an approach for automating the identification and localization of construction components on large industrial projects. The proposed approach combines advanced sensing devices and localization mechanisms. The appropriate combination of global positioning system and radio-frequency identification (RFID) facilitates an infrastructure-free data collection process capable of detecting a large number of RFID-tagged components in short amounts of time. Based on the collected data, localization mechanisms precisely estimate the coordinates of the tagged components. Field experiments on real construction scenarios demonstrated the feasibility of the proposed methodology.