Hydrodynamic aspects of venting for vessels containing viscous fluids

Nine depressurization experiments for vessels containing water, freon-114 and high viscosity fluids have been analyzed. These experiments were carried out at different plants and provide information about the dependence of the depressurization process on the size of the vessel, the type of vent installed, and the initial conditions. The differences of venting into the atmosphere or venting into a catch tank have been also examined. The accuracy of the two-phase flow model used for the analysis of these experiments has been demonstrated by comparisons with steady state data referring to co-current liquid/vapor flow as well as to batch type of flows, where the liquid phase is stagnant.     

基于振动测试的印刷机滚筒轴向串动研究

印刷滚筒采用斜齿轮传动是现代印刷机的基本要求,该传动过程中必然在轴线方向产生一个分力,这个分力会使滚筒在轴向方向上产生一个较小的位移,即轴向串动。印刷过程中,滚筒的轴向位移量过大或过小,都会对印刷品产生不良影响,滚筒的轴向串动量成为鉴定印刷机性能的重要指标之一。为了在高速运转情况下,有效地掌握和控制滚筒轴向串动量,本实验采用激光多普勒测振仪,以某四色印刷机作为测试对象,通过合理地在滚筒上选定测点,采集了橡皮滚筒、压印滚筒及传纸滚筒的轴向振动信号,并通过求积分,得到各滚筒在不同速度下的轴向串动量,并进行了分析,结果显示印刷速度越高,同种滚筒的轴向串动量越大,表明串动量的大小跟印刷速度有关。在相同速度下,橡皮滚筒与压印滚筒、传纸滚筒的串动量差距较大,表明滚筒串动量大小跟滚筒的装配结构有关。测试结果与滚筒实际结构和装配情况一致,可作为控制滚筒串动量大小的依据。     

基于天然气放空系统的水力计算软件开发

高压天然气放空系统由放空干线管段气体、放空管线及外界大气组成。放空管路属于非稳定流动,其水力计算不能采用一般站场管路的达西公式。以Fano方程为基础,运用流体力学及输气管路流动基础理论进行程序编写,计算软件可实现对各时刻放空所对应的瞬时放空量、累计放空时间、截面压力及温度、储气量的求解。计算结果与图解法进行对比,误差控制在2%以内,弥补了图解法仅可求得瞬时放空量而无法得到其他参数的缺陷,并利用东河伴生气管线下沉工程现场放空数据与本计算软件对比,计算结果吻合度高,符合现场工程实际。     

Diagonal Merger

Diagonal merger combines the assets of an input supplier and a downstream rival of the input demander that does not use the input. Diagonal mergers are likely to be overlooked by federal antitrust authorities as they are neither vertical nor horizontal mergers. Diagonal mergers are shown to be nearly as anticompetitive as comparable horizontal mergers and, like horizontal mergers, the welfare effects of diagonal mergers are predicted in the first instance by a modified HHI calculation.     

Explosion within a helium purifier

A cryogenic charcoal adsorber used to purify helium for cylinder filling exploded on August 26, 1988 at an Air Products facility in Belgium. Although the feed gas contained only 1.4% oxygen, calculations confirm that a liquid phase containing approximately 85% oxygen could have formed at the inlet to the bed and soaked into the charcoal. This potent explosive mixture (up to 7 times more powerful than TNT) was probably ignited by the flow surge when the bed depressurized to allow change-over from a full to an empty bank of cylinders. Parts of the vessel were recovered up to 250 meters from the installation and windows were cracked by the shock wave at approximately 60 meters. These consequences are consistent with the calculated energy available (approximately 40 lb TNT). Fortunately no one was injured. Two other recent explosions in the industry further emphasize the potential concerns of carbon bed cryogenic purifiers of oxygen containing gases.     

Experiments on the thermo-hydraulic response of pressure liquefied gases in externally heated tanks with pressure relief

An experimental program is described and experimental results presented for the response of an externally heated horizontal cylindrical tank protected by a PRV and partially filled with a pressure liquefied gas. Measurements of tank pressure, temperatures, mass discharge and void development, along with photography of internal fluid behavior are used to demonstrate the complex thermo-hydraulic behavior as a function of heating and valve position. The results are used to compare some of these parameters with analyses of stratification and void development.     

鱼骨水平井在高效开发边台潜山中的应用

边台潜山属于低孔低渗透的裂缝性油气藏,并且在纵向上的层位厚度不均,裂缝发育差,属于难动用油藏。通过应用多分支鱼骨水平井技术,明显提高了开发效果。以一口上下双层分支、每分支带鱼骨的井为例,系统论述了鱼骨水平井设计依据,施工关键技术及开发效果,为今后开发此类难动用油气藏提供了借鉴。     

Dust explosion venting for dusts pneumatically conveyed into vessels

The size of venting areas of containers in dust explosions has hitherto been calculated by use of nomograms developed from tests in which explosible dust-air mixtures were produced by rapid discharge of combustible dust from storage containers. Such tests did not truly reflect the conditions prevailing when containers are charged with product in industrial practice. There was, therefore, a need to perform dust explosion tests with vented containers and pneumatic product filling. The results of such tests show that there is a considerable reduction in the venting area in comparison with that predicted from results obtained with earlier test procedures.     

Specification of flame arresting devices for manifolded low pressure storage tanks

The current regulations and accepted recommended practices relating to the use of mechanical flame arresting devices on low pressure, flammable liquid storage tanks will be reviewed. The applicability of these recommendations to typical manifolded tank and closed piping vapor recovery systems, as opposed to the more common “stand alone”, venting to atmosphere storage tanks, will be examined with particular emphasis on the widely varying service conditions that mechanical flame arresting devices may encounter. The limitations placed on the use of commercially available Factory Mutual Approved and Underwriters Laboratories Listed flame arresters will be explained.     

Vertical and Horizontal Cross‐Ties: Benefits of Cross‐Hierarchy and Cross‐Unit Ties for Innovative Projects

Social networks are an important driver for successful innovation, both at the individual level as well as the organizational level. Recent research has also shaped that networks within teams can enhance performance. Innovative project teams are embedded in an organizational context, however, and teams typically consist of people with expertise from diverse backgrounds, and from different units. Team members may have ties to other teams, business units, and hierarchical levels. Although it seems clear that such ties can influence team performance, remarkably little research has focused on what is here referred to as vertical and horizontal cross‐ties. Previous research may have ignored the possibility that vertical and horizontal bridging ties may have different performance outcomes. Although the literature suggests that diversity of input, or horizontal cross‐unit ties will benefit team performance and innovativeness, there is reason to believe that ties to higher levels in the organization might have an effect on project team performance and innovativeness too. This article in particular studies the role of vertical cross‐hierarchy ties. In an exploratory analysis combining quantitative and qualitative results, it is distinguished between horizontal cross‐unit and vertical cross‐hierarchy ties and their contribution to new business development (NBD) project performance, thereby making a substantial contribution to both academic literature and managerial practice. Our study is based on a multiple case‐study approach of several NBD project teams in a large European financial service provider. Our results show that successful innovation project teams are characterized by a large number of cross‐unit ties in combination with a large number of cross‐hierarchical ties compared with less successful project teams. Additionally, proof is found that vertical cross‐hierarchy ties should be concentrated rather than scattered across project members.     

基于动态因子分析法的区域开放型经济发展水平测度研究

既有区域开放型经济发展水平的测度研究仍主要以静态分析为主,动态分析尚显不足。本文基于最新研究进展,通过构建开放型经济发展水平测度指标体系,截取2005～2014年各区域统计年鉴相关指标数据,并借助STATA统计分析工具,运用动态因子分析法测度研究我国区域开放型经济发展水平及其变化趋势,从横向和纵向两条线分析我国区域开放型经济发展水平并提出相关对策及建议。实证研究表明：（1）从空间分布状态来看,我国区域开放型经济发展水平自东向西逐步降低,与区域经济发展水平呈现高度相关关系;（2）从时间维度动态趋势变化来看,开放型经济发展水平呈现V、倒V、M、W 4种变化趋势,同时存在时间和空间上的规律性。基于实证结果提出扩大内陆地区全方位开放格局及协调产业体系建设和进一步完善开放型经济发展新体制的发展思路。     

关于弯曲液面蒸气压的两点讨论

以外压对蒸气压的影响及开尔文方程为理论依据,讨论了外压对弯曲液面蒸气压的影响,其结果与外压对平液面蒸气压的影响相同。讨论了液体内部气泡的蒸气压,给出了气泡内蒸气压的计算公式,并对现实中的实例进行了计算说明。     

A smart place to work? Big data systems,labour, control and modern retail stores

The modern retail store is a complex coded assemblage and data‐intensive environment, its operations and management mediated by a number of interlinked big data systems. This paper draws on an ethnography of a retail store in Ireland to examine how these systems modulate the functioning of the store and working practices of employees. It was found that retail work involves a continual movement between a governance regime of control reliant on big data systems which seek to regulate and harnesses formal labour and automation into enterprise planning, and a disciplinary regime that deals with the symbolic, interactive labour that workers perform and act as a reserve mode of governmentality if control fails. This continual movement is caused by new systems of control being open to vertical and horizontal fissures. While retail functions as a coded assemblage of control, systems are too brittle to sustain the governmentality desired.     

The anatomy of an acrylic acid runaway polymerization

The details of an unscheduled polymerization of acrylic acid initiated by indirect heating have been characterized by in-depth analysis of the polymer, kinetic and thermodynamic calculations, and heat and material balances on the system. The data fit together to give a consistent picture of the polymerization scenario. The fact that the acrylic acid polymerization was not violent was primarily due to the presence of about 10 ppm phenothiazine, which delayed the onset of free radical polymerization until about 2 to 3 hours after the monomer had reached its boiling point. Since much of the acrylic acid was converted to dimer during this induction period, the ultimate energy release was greatly limited. Other moderating factors were a relatively slow heatup of the tank contents in the external heat exchange recycle loop, free vapor venting, and the incursion of fire monitor water into the tank.     

企业信息结构、人力资本专用性与人力资源管理模式的选择

由谁观察信息，观察什么信息，怎样传递信息构成了企业内部的信息结构。一般而言，企业的信息结构分成横向信息结构和纵向信息结构两种。横向信息结构与专用性人力资本，纵向信息结构与通用型人力资本相互匹配。相对应地，企业要形成不同的人力资本必须采取不同的人力资源管理模式。对以纵向信息结构为主的企业应该采取外部化人力资源管理模式，而对以横向信息结构为主的企业应该采取内部化人力资源管理模式。     

Resource allocation for open and hidden learning in learning alliances

A satisfying relationship between alliance members is important for the success of learning alliances, especially those in the Asia Pacific region. While learning alliances create conditions for firms to leverage each other’s knowledge, firms may be opportunistic and appropriate each other’s knowledge, and firms face a tradeoff because appropriation affects the relationship between alliance members. After reviewing previous studies on knowledge sharing in learning alliances, we differentiate firms’ learning into open and hidden learning, and argue that open learning contributes to competence trust, while hidden learning reduces goodwill trust, which consequently affects open learning. Learning uncertainty, introduced in this study, and learning benefits determine expected payoffs of open and hidden learning, which influence firms’ resource investment in them. This study also finds that behavior and output control are important moderators of the relationships between expected payoffs of open and hidden learning and the resources invested in them. Thus, this study advances our understanding of the tension between cooperation and competition and the learning dynamics in learning alliances. The solution to solving the knowledge sharing dilemma in learning alliances is to promote partners’ open learning and to restrain their hidden learning. Therefore, this study argues that, with open and hidden learning, implementing proper control measures and influencing partners’ learning benefits and uncertainties can settle this dilemma. Furthermore, this study classifies the relationships of learning alliances into four types and gives an explanation of why horizontal learning alliances are usually more competitive than vertical ones.     

两圆柱相贯线简化画法的误差估计

两轴线相互垂直的圆柱相交,其相贯线(表面的交线)一般为空间曲线(其投影一般为双曲线)。有时,为了简化作图,在平行其公共对称平面的投影面上的投影往往采用以两圆柱中较大圆柱半径为半径的圆弧代替双曲线。通过对正交两圆柱表面交线的数学表达式及投影图、误差曲线图等多方面的考察分析,提出在投影图上使用圆弧代替双曲线的合适范围与条件。     

Advertising with Subjective Horizontal and Vertical Product Differentiation

In this paper, we analyze the impact of advertising on markets wheresubjective horizontal and vertical product differentiation are important. A simple model showshow advertising can be used to create subjective horizontal and vertical differentiation.The model predicts that firms are likely to be symmetric when advertising creates subjective horizontaldifferentiation and that name and generic brands are most likely to coexist in markets whereadvertising creates subjective vertical differentiation. In all cases, the ability toadvertise creates distance between products which increases the market power of firms. Finally, severalreal world examples are used to illustrate the conditions under which the model is most relevant.     

Strategizing industry structure: the case of open systems in a low‐tech industry

Open systems strategy enables a sponsor to diffuse its technology and promotes standardization in an industry. However, this strategy has been studied in high‐tech settings. We hypothesize that, in a non‐high‐tech industry, a sponsor giving access to its technical knowledge may impact industry structure. Based on a survey of the U.S. tabletop role‐playing game (RPG) industry, our results highlight that the introduction of an open system in a sector creates an entry induction phenomenon and that these new entrants adopt more readily the open system than incumbents. Moreover, the average size of the firms in the industry decreases due to vertical specialization. Copyright © 2006 John Wiley & Sons, Ltd.     

Vertical and Horizontal Scope Economies in the Regulated U.S. Electric Power Industry

This paper investigates vertical economies between generation and distribution of electric power, and horizontal economies between different types of power generation in the U.S. electric utility industry. Our quadratic cost function model includes three generation output measures (hydro, nuclear and fossil fuels), which allows us to analyze the effect that generation mix has on vertical economies. Our results provide (sample mean) estimates of vertical economies of 8.1% and horizontal economies of 5.4%. An extensive sensitivity analysis is used to show how the scope measures vary across alternative model specifications and firm types.