Damping Effect on Waves Propagating Past a Submerged Horizontal Plate and a Vertical Porous Wall

A set of analytical solutions for waves propagating past a combined submerged horizontal plate and vertical porous wall breakwater system is presented. The wave damping effect caused by the horizontal plate induced flow constriction is considered in the analysis. The velocity potentials in each fluid domain are derived based on the linear wave theory and the unknown coefficients are determined from the matching conditions using three sets of orthogonal eigenfunctions. Reflection and transmission coefficients are presented to evaluate the performance of the breakwater system. The analytical solutions in terms of the reflection and transmission coefficients as well as the hydrodynamic force on the vertical porous wall are found in good agreement with published laboratory measurements. In comparison with the solutions without taking into account the wave damping effect, the present analytical solutions significantly improve the accuracy of the wave predictions, especially for the reflected waves.     

Capacity, Settlement, and Energy Dissipation of Shallow Footings Subjected to Rocking

The effectiveness of structural fuse mechanisms used to improve the performance of buildings during seismic loading depends on their capacity, ductility, energy dissipation, isolation, and self-centering characteristics. Although rocking shallow footings could also be designed to possess many of these desirable characteristics, current civil engineering practice often avoids nonlinear behavior of soil in design, due to the lack of confidence and knowledge about cyclic rocking. Several centrifuge experiments were conducted to study the rocking behavior of shallow footings, supported by sand and clay soil stratums, during slow lateral cyclic loading and dynamic shaking. The ratio of the footing area to the footing contact area required to support the applied vertical loads (A/Ac), related to the factor of safety with respect to vertical loading, is correlated with moment capacity, energy dissipation, and permanent settlement measured in centrifuge and 1 g model tests. Results show that a footing with large A/Ac ratio (about 10) possesses a moment capacity that is insensitive to soil properties, does not suffer large permanent settlements, has a self-centering characteristic associated with uplift and gap closure, and dissipates seismic energy that corresponds to about 20% damping ratio. Thus, there is promise to use rocking footings in place of, or in combination with, structural base isolation and energy dissipation devices to improve the performance of the structure during seismic loading.     

CFRP-Based Strengthening Technique to Increase the Flexural and Energy Dissipation Capacities of RC Columns

A strengthening technique, combining carbon fiber-reinforced polymer (CFRP) laminates and strips of wet layup CFRP sheet, is used to increase both the flexural and the energy dissipation capacities of reinforced concrete (RC) columns of square cross section of low to moderate concrete strength class, subjected to constant axial compressive load and increasing lateral cyclic loading. The laminates were applied according to the near surface mounted technique to increase the flexural resistance of the columns, while the strips of CFRP sheet were installed according to the externally bonded reinforcement technique to enhance the concrete confinement, particularly in the plastic hinge zone where they also offer resistance to the buckling and debonding of the laminates and longitudinal steel bars. The performance of this strengthening technique is assessed in undamaged RC columns and in columns that were subjected to intense damage. The influence of the concrete strength and percentage of longitudinal steel bars on the strengthening effectiveness is assessed. In the groups of RC columns of 8 MPa concrete compressive strength, this technique provided an increase of about 67% and 46% in terms of column’s load carrying capacity, when applied to undamaged and damaged columns, respectively. In terms of energy dissipation capacity, the increase ranged from 40%–87% in the undamaged columns, while a significant increase of about 39% was only observed in one of the damaged columns. In the column of moderate concrete compressive strength (29 MPa), the technique was even much more effective, since, when compared to the maximum load and energy dissipation capacity of the corresponding strengthened column of 8 MPa of average compressive strength, it provided an increase of 39% and 109%, respectively, showing its appropriateness for RC columns of buildings requiring upgrading against seismic events.     

Performance Test of Energy Dissipation Bearing and Its Application in Seismic Control of a Long-Span Bridge

Energy dissipation bearing (EDB) is a conventional steel bridge bearing in connection with well designed mild steel dampers. Seismic performance test was undertaken for both damper units and a prototype bearing, and the results show very stable and high dissipation characteristics. In describing the hysteretic behavior of EDBs, the Wen model is proved to be more reasonable, and the corresponding model parameters are also proposed according to the test results. EDBs have been applied in the seismic control of a long span bridge, the Nanjing Jia River Bridge, for the first time, in both the longitudinal and transverse directions. Sensitivity studies were conducted to investigate the effectiveness and to determine the optimum parameters and distribution of the EDBs through nonlinear time-history analysis. The results show that EDBs achieve a very high effectiveness in seismic control, in both the longitudinal and transverse directions. Compared with other damping devices, they can provide a simple but valid seismic control solution, with low maintenance requirements, especially in the transverse direction.     

“Biaxiality Effect” on the Energy Dissipated by Elastoplastic Base-Isolators

A plane elastic-plastic solid body presenting kinematic hardening is used to simulate a pair of dampers at the base of a rigid structure and determine the energy dissipation under conditions of assigned, homogeneous cyclic loading. The well-known von Mises theory of plasticity is applied with the aim of obtaining analytical solutions to the problem. Such solutions are arrived at by first calculating the Odqvist parameter, which yields dimensionless relations that depend on the external loads and mechanical properties of the material. The results, in terms of dissipated energy, are given for the case of a sinusoidal process, represented with the help of dimensionless parameters useful for engineering applications.     

热处理工艺对压力容器钢板组织和性能的影响

近年来,随着我国石油化工行业的快速发展,各种石油化工工艺以及设备都在不断推陈出新,在此过程中,各种气化产品的液化、分离、贮存以及运输也已经成为极为常见的现象。压力容器作为盛装这些低温气化产品的最主要工具,市场需求也变得越来越大。随之也带动了压力容器用钢需求量的激增。但是随着压力容器用途的日益广泛,不同用途中对压力容器用钢的要求也存在差异,这就给压力容器制造企业提出了更高了要求。热处理工艺是压力容器钢板生产过程中最重要的处理工艺之一,只有经过了不同形式的热处理,才能使钢板的组织及性能发生变化,并最终使用于制造压力容器的钢板具备更多更加完善的性能。本研究就是在此基础上,以07系列压力容器钢为例,对其热处理工艺进行了系统研究。经过不同工艺的热处理,分别对不同工艺下的淬火温度及保温时间,以及回火温度等对钢板的组织及性能的影响进行了分析。并最终根据实验结果得出,针对不同厚度的实验钢,应当尽量在淬火实验的温度控制在900℃~920℃之间,而回火温度的设定则主要根据实验钢板的厚度来进行设定,通常需要控制在600℃~650℃之间。通过本次实验研究,以期能对今后压力容器钢实际生产过程中的相关工艺的应用起到指导作用。     

降低水平电流减少铝液动态波动铝电解节能技术研究

通过计算机模拟仿真研究复合稳流综合节能技术对铝电解过程中阴极铝液内水平电流的影响。结果表明,以高导电方钢为核心的复合稳流综合节能技术可明显降低阴极铝液内水平电流大小,降低电解质-铝液界面变形,提高电解槽内磁流体的稳定性,以此来降低槽电压和提高电流效率,达到节能降耗的作用。为验证仿真模拟结果,在某企业300 kA系列电解槽进行复合稳流综合节能技术工业化试验,采用以高导电钢棒为核心的复合稳流综合节能技术,电解槽内水平电流降低明显,获得了非常小的铝液界面变形量,电解槽生产运行稳定性明显提高,吨铝直流电耗较系列传统槽、201技术槽、双钢棒技术槽都低。     

中厚板矫直机弯辊装置结构分析

介绍了中厚板矫直机弯辊装置中各部件的力传递关系，并对弯辊缸收缩、弯辊装置上弯时各构件力的关系以及弯辊缸伸张、弯辊装置下弯时各部件力的关系进行了分析。由此，可以精确确定弯辊力以及弯辊装置各部件力的关系，以便于结构设计，更有效地提高板材的矫直质量。     

厚钢板坯料生产制备方法的研究

本文介绍了厚板坯料的几种生产制备方法,对比了不同方法的特点,推荐了坯料生产制备方法。     

谈氧气厂节能降耗的途径

以首钢氧气厂为例，较为详细地论述了节能降耗是氧气厂降低氧气成本的重要途径。以及为实现这一途径而采取的四项主要措施，并有重点地介绍了如何降低氧气放散而采用的各种方法。     

Impact of the Leadership in Energy and Environmental Design Accredited Professional Credential on Design Professionals

Leadership in energy and environmental design (LEED) accreditation is quickly becoming one of the most popular professional designations available to members of the building design and construction community. The purpose of this research was to determine the impact that the LEED accredited professional (AP) designation has had on architecture/engineering (A/E) firm employees versus employees of owners, contractors, subcontractors, and other organization types. The researchers analyzed 9,060 responses from LEED-APs using a one-way ANOVA to determine whether or not significant differences in perceived benefit exist between LEED-APs working for A/E firms and LEED-APs working for other organization classifications. Results indicated a statistically significant difference in six of the eight “impact” categories. LEED-APs working for A/E firms did not feel as strong as LEED-APs working for other organization types that the credential provided any more recognition, professional opportunities for contributions, and prestige among superiors and individuals within their organization. There were no significant differences between the groups, however, with regard to the credential’s impact on salary and job responsibilities.     

宝钢三期工程能源设施初探

本文分析了宝钢一、二期工程能源设施配置现状，提出了三期工程能源设施配置的基本原则和供配电、燃气、制氧、热力、给排水各系统的方案。     

浅孔留矿与中深孔爆破联合回采复杂矿体技术研究

山东玲珑金矿九曲分矿在回采中遇到中厚矿体时,采用传统浅孔留矿采矿法存在一些问题,即采场顶板暴露面积过大,安全得不到保证,矿石回收率低.通过采用浅孔留矿采矿法结合中深孔爆破,能保障作业人员的安全,提高矿石回收率,缩短矿块回采周期,是传统浅孔留矿采矿法回采中厚矿体的一种新的尝试.     

薄板坯连铸连轧生产冷轧基板的工艺与组织性能分析

比较分析了薄板坯连铸连轧的工艺特征,轧制工艺特点及板坯热历史,第二相粒子的析出行为,传统流程与TSCR流程中低碳钢的组织、析出、位错、性能差异等,结合薄板坯连铸连轧生产低碳钢板力学性能的生产统计结果实例,提出了冷轧冲压板用热轧基板的成分和性能要求及解决的途径,并给出了在CSP线上进行冷轧基板的冶金成分与工艺控制的生产性试验的初步结果.     

关于0Cr18Ni9不锈中板旋压封头开裂问题原因分析

针对一起用户使用中发生的质量问题，从钢板材质、用户使用情况、金相组织、夹杂物分析入手分析，确认产生问题的原因，提出处理建议。     

醋酸纤维富集-ICP-AES测定高品位氰化液体中金、银含量

由于氰化液体的特殊性,常用的分析方法都不能获得理想的回收率,方法的精密度不高,影响了对工艺指标的控制,并且碱性氰化液体会对仪器造成很大程度的腐蚀,降低仪器的使用寿命及稳定性,增加了工作成本。通过将高品位氰化液体酸化,在一定浓度的王水介质中,用经有机溶剂浸泡过的醋酸纤维吸附富集溶液中的金、银,再用20 g/L的硫脲溶液在水浴加热条件下解吸,采用ICP-AES测定硫脲介质下的金、银,金、银的回收率为98.5%～100.5%,方法的检出限金为0.0021,银为0.0030。     

Evaluation of Interslice Force Function and Discussion on Convergence in Slope Stability Analysis by the Lower Bound Method

The interslice force function f(x) is a major assumption of the limit equilibrium method, which is important but has not been adequately considered in the past. In this paper, f(x) is taken as the control variable, and the upper and lower limits of the factor of safety for a general slope will be determined by a global optimization analysis. Based on this approach, f(x) will be determined and investigated. We demonstrate that f(x) cannot be arbitrarily assigned if a set of acceptable internal forces is required. The present approach can be presented practically as a lower bound approach with the advantage that failure to converge is virtually eliminated, which is not possible with all other existing “rigorous” methods. The “present proposal” attempts to answer several important questions in the basic theory of slope stability analysis, and provides a f(x) based on the lower bound approach statically admissible forces throughout the whole failure zone. Currently, different assumptions will give different factors of safety to the same problem, and this situation will be overcome by the use of the present proposal. The present proposal is also proven to give a result equal to the slip line solution for a simple footing on clay which is not possible for other classical slope stability methods, which has demonstrated that the applicability of the “present proposal” for general difficult problems.     

1号高炉炉壳开孔后的有限元静力和屈曲分析

宝钢１号高炉大修时在炉壳上要开３个人孔，为此，为炉壳进行静力和屈曲稳定性有限元分析，并和不开孔的高炉炉壳分析结果作比较，结果表明，尽管开孔后的炉壳刚度，强度和屈曲稳定性临界载荷系数有变化，但影响不大，还是安全的，可以实施这样的开孔方案。     

硫氨酯尾液法生产的巯基乙酸钠中的黄药降解及选矿效果研究

由于硫氨酯尾液法生产的巯基乙酸钠残存黄药,影响巯基乙酸钠的抑制效果.为了降低巯基乙酸钠中黄药的残存量,通过避光静置试验、加热试验、以及改变硫氨酯尾液法生产工艺的酯化温度和酯化时间试验,最终确定了硫氨酯尾液法生产工艺的酯化温度为58℃、酯化时间为100 min时,巯基乙酸钠中的黄药量能够降低至500 mg/L以下.通过浮...     

氧分压对直流磁控溅射铟锡氧化物(ITO)导电薄膜结构和性能的影响

通过直流磁控溅射热等静压铟锡氧化物(ITO)靶材制备ITO导电薄膜,并且针对O2-Ar混合气氛中氧的分压对ITO膜的结构、表面形貌、透光率以及导电率的影响进行了研究.结果表明,在低氧分压的条件下溅射,膜的(400)面非常显著地择优取向平行于玻璃表面,而随着氧分压的升高却表现为膜的(222)面择优取向平行于玻璃表面.同时,随着氧分压的升高,膜的表面粗糙度变小,膜的结构变得更细腻.膜的可见光透过率在氧分压增大的情形下有少许增大,但是膜的导电率却略有下降.