Disengagement predictions via drift flux correlation vertical,horizontal and spherical vessels

The behavior of an open system is modeled. Thus, for special cases, the void fraction is predicted as a function of location and time. The open system may be an open vessel or a vessel with an open relief device. A single governing equation is derived based on combining the material and energy balances with the churn-turbulent drift flux relationship and assuming no radial gradients. This partial differential equation is not solved. It is, however, bounded by homogeneous and all vapor venting. These special cases are solved. In homogeneous venting the key variable is time. In all vapor venting under pseudo-steady-state conditions the key variable is location. The solution of the partial differential equation is also discussed. Under pseudo-steady-state and churn-turbulent conditions, the open system is modeled. The minimum void fractions (corresponding to a maximum liquid inventory) with all vapor venting, for vertical, horizontal, and spherical vessels are predicted and compared. Analytical expressions for the local and average void fractions in a vertical vessel and non-unity distribution parameters are presented. Void fraction profiles are compared for three cases: 1. vertical cylinders with distribution parameters (Co values) of unity and 1.5, 2. horizontal and vertical cylinders with varying L/D ratios, and 3. spheres with inscribed vertical cylinders having constant gas production to bubble rise ratio (Ψ′ value). The vertical cylinder average void fraction for non-unity distribution parameters can now be calculated analytically. The horizontal cylinder average void fraction predicted by turning it upright results in an over prediction of at most 4%. The sphere average void fraction predicted via an inscribed vertical cylinder, with the same Ψ′ value, is consistenly high by at most 8%.     

Ultimate capacity of blast loaded structures common to chemical plants

There has been a great deal of investment in development of design criteria and design and construction of heavily reinforced, blast-resistant control rooms. This remains the best option for protective construction against severe blast loading experienced close in to a vapor cloud or other explosion hazard. However, most structures encountered at chemical plants and contemplated for future construction are conventional steel frame, metal clad buildings. In this paper we look closely at the response of such buildings to explosion loads and their ability to undergo large deformations without structural failure. The types of structural elements evaluated include metal decking of various gauge and shape along with a variety of girt and purlin sections. Building frames or bents are also evaluated, although the date base for these is much more limited. The work is based on observations made during investigations of large explosion accidents along with analytical predictions and test measurements. To conclude, we offer specific design criteria and connection recommendations for enhancing the overall strength of a building through the use of conventional components in unconventional construction.     

Gender Pay Gap,Voluntary Interventions and Recession: The Case of the British Financial Services Sector

State institutions and trade unions put pressure on the British financial services sector to reform its gendered practices and reduce its gender pay gap following both the recession and the Equality and Human Rights Commission (EHRC) Inquiry (2009). This article considers the effect of these pressures by comparing the gender pay gap pre‐, during‐ and post‐recession periods. Using Labour Force Survey data, the article finds a marginal pay gap reduction in the post‐recession period, a reduction that was greater in financial services than in the rest of the economy. However, the financial services pay gap remained resilient and substantially higher at the top of the earnings distribution. Union membership and collective bargaining were shown to reduce the pay gap including for women members with children. In contrast, countervailing factors, including ethnicity and post‐recession longer working hours, contributed to the pay gap. The study reveals the limitations of voluntary interventions against a resilient gendered culture.     

Re‐Examining Advances in Occupational Licensing Research: Issues and Policy Implications

Much has changed in the realms of occupational licensing since BJIR last ran a special issue on the subject in 2010. The number of occupations subject to licensing has been growing, the data available to investigate the incidence and effects of licensing have improved immeasurably, and the policy environment surrounding licensing has changed. This issue reflects these changes with eight papers from North America and Europe covering the incidence of licensing, and its effects on wages, inequality, employment, quality of service provision and rent extraction by the organizations who undertake licensing.     

Strategic Dilemmas: How Managers Use HR Practices to Meet Multiple Goals

Contrary to the classic assumptions in the business and human resource (HR) strategy literatures, real‐world organizations often pursue multiple and potentially contradictory performance goals. They may adopt ‘hybrid’ strategies to maximize both differentiation and low cost — leading middle managers to face dilemmas in how to achieve different goals using the same HR practices. We link employee‐level surveys of HR practices to establishment‐level data on service quality, labour efficiency and profitability to examine the effects of HR practices on these outcomes. We find that establishments with greater use of high involvement practices have significantly higher service quality, which mediates the relationship between HR practices and profitability. Findings for labour efficiency are positive, but generally not significant. These findings also have implications for the quality of jobs.     

Learning patterns in early stage R&D projects: empirical evidence from the fibre raw material technology project in the Netherlands

Past research has reported that learning processes in early stage R&D are either chaotic, or absent. We challenge this finding by elaborating Van de Ven et al.’s trial‐and‐error learning model and explore an alternative conceptualization. We explored the combinations of positive and negative outcomes and action course continuation and modification. We use data gathered in an R&D setting of a 4‐years pre‐competitive knowledge generation project in the Dutch paper and board industry. Whereas the Van de Ven and Polley (1992) approach applied on our data also would lead us to conclude that ‘no learning’ would happen, our decomposed model identified three distinct learning patterns: (1) a virtuous pattern of positive outcomes resulting in continuations of action courses; (2) a vacuous pattern of negative outcomes resulting in modifications of action courses; and (3) a verification pattern of positive outcomes resulting in modifications of action courses. We observed the virtuous and verification patterns during the first 2 years and virtuous and vacuous learning in the second 2 years. These results might be useful for R&D managers since they provide insight into how an early stage R&D project can develop and where managers might intervene and adjust action courses.     

The economic and poverty impacts of maize research in West and Central Africa

This article assembles the results of three multicountry surveys on variety performance and adoption patterns to measure the impacts of maize research in West and Central Africa from 1981 to 2005, and uses cost data since 1971 to compute social rates of return on public investments in maize research in the region. Adoption of modern varieties increased from less than 5% of the maize area in the 1970s to about 60% in 2005, yielding an aggregate rate of return on research and development (R&D) investment of 43%. The estimated number of people moved out of poverty through adoption of new maize varieties rose gradually in the 1980s to more than one million people per year since the mid 1990s. Over half of these impacts can be attributed to international maize research at IITA and CIMMYT. The article concludes with a discussion of strategic options to enhance the impacts of maize research in the region.     

The economic potential of precision nitrogen application with wheat based on plant sensing

Plant-based precision nitrogen fertilizer application technologies have been developed as a way to predict and precisely meet nitrogen needs. Equipment necessary for precision application of nitrogen, based on sensing of growing wheat plants in late winter, is available commercially, but adoption has been slow. This article determines the expected profit from using a plant-sensing system to determine winter wheat nitrogen requirements. We find that plant-sensing systems have the potential to be more profitable than traditional nonprecise systems, but the existing system simulated was roughly breakeven with a traditional system.