Numerical and Experimental Study of the Performance Effects of Varying Vaneless Space and Vane Solidity in Radial Inflow Turbine Stators.

An extensive experimental program has been carried out on a 135?mm tip diameter radial turbine using a variety of stator designs, in order to facilitate direct performance comparisons of varying stator vane solidity and the effect of varying the vaneless space. A baseline vaned stator was designed using commercial blade design software, having 15 vanes and a vane trailing edge to rotor leading edge radius ratio (Rte/rle) of 1.13. Two additional series of stator vanes were designed and manufactured; one series having varying vane numbers of 12, 18, 24, and 30, and a further series with Rte/rle ratios of 1.05, 1.175, 1.20, and 1.25. As part of the design process a series of CFD simulations were carried out in order to guide design iterations towards achieving a matched flow capacity for each stator. In this way the variations in the measured stage efficiency could be attributed to the stator passages only, thus allowing direct comparisons to be made. Interstage measurements were taken to capture the static pressure distribution at the rotor inlet and these measurements were then used to validate subsequent numerical models. The overall losses for different stators have been quantified and the variations in the measured and computed efficiency were used to recommend optimum values of vane solidity and Rte/rle.

Developing a conceptual model of lead performance measurement and benchmarking: A multiple case analysis

Purpose: Environmental turbulence including rapid changes in technology and markets has resulted in the need for new approaches to performance measurement and benchmarking. There is a need for studies that attempt to measure and benchmark upstream, leading or developmental aspects of organizations. Therefore, the aim of this paper is twofold. The first is to conduct an in-depth case analysis of lead performance measurement and benchmarking leading to the further development of a conceptual model derived from the extant literature and initial survey data. The second is to outline future research agendas that could further develop the framework and the subject area.

Design/methodology/approach: A multiple case analysis involving repeated in-depth interviews with managers in organisational areas of upstream influence in the case organisations.

Findings: It was found that the effect of external drivers for lead performance measurement and benchmarking was mediated by organisational context factors such as level of progression in business improvement methods. Moreover, the legitimation of the business improvement methods used for this purpose, although typical, had been extended beyond their original purpose with the development of bespoke sets of lead measures.

Practical implications: Examples of methods and lead measures are given that can be used by organizations in developing a programme of lead performance measurement and benchmarking.

Originality/value: There is a paucity of in-depth studies relating to the theory and practice of lead performance measurement and benchmarking in organisations.

Exploring Children's Stereotypes Through Drawings: The Case of Musical Performance

Drawings of 'a person' and of 'a person playing music' were collected from children aged seven to eight years and 10-11 years to discover whether children's musical representations would reflect gender differences evident in musical learning and performance, and the increased gender rigidity with age found in instrument preferences. As in previous drawing studies, same sex figures were overwhelmingly portrayed, although older girls drew more opposite sex figures than the other children. All except the older girls overwhelmingly drew same sex musicians irrespective of the gender stereotype of the instrument portrayed. The older girls drew similar numbers of male and female figures playing masculine instruments. Fewer feminine instruments were drawn by older than by younger boys. The increased gender rigidity with age accords with the results of the preference studies, but gender stereotyping was much weaker. This is discussed in relation to what the different methodologies measure.

Dynamical instability in surface permeability characteristics of building sandstones in response to salt accumulation over time

This paper explores how the surface permeability of sandstone blocks changes over time in response to repeated salt weathering cycles. Surface permeability controls the amount of moisture and dissolved salt that can penetrate in and facilitate decay. Connected pores permit the movement of moisture (and hence soluble salts) into the stone interior, and where areas are more or less permeable soluble salts may migrate along preferred pathways at differential rates. Previous research has shown that salts can accumulate in the near-surface zone and lead to partial pore blocking which influences subsequent moisture ingress and causes rapid salt accumulation in the near-surface zone.

Two parallel salt weathering simulations were carried out on blocks of Peakmoor Sandstone of different volumes. Blocks were removed from simulations after 2, 5, 10, 20 and 60 cycles. Permeability measurements were taken for these blocks at a resolution of 20 mm, providing a grid of 100 permeability values for each surface. The geostatistical technique of ordinary kriging was applied to the data to produce a smoothed interpolation of permeability for these surfaces, and hence improve understanding of the evolution of permeability over time in response to repeated salt weathering cycles.

Results illustrate the different responses of the sandstone blocks of different volumes to repeated salt weathering cycles. In both cases, after an initial subtle decline in the permeability (reflecting pore blocking), the permeability starts to increase — reflected in a rise in mean, maximum and minimum values. However, between 10 and 20 cycles, there is a jump in the mean and range permeability of the group A block surfaces coinciding with the onset of meaningful debris release. After 60 cycles, the range of permeability in the group A block surface had increased markedly, suggesting the development of a secondary permeability. The concept of dynamic instability and divergent behaviour is applied at the scale of a single block surface, with initial small-scale differences across a surface having larger scale consequences as weathering progresses.

After cycle 10, group B blocks show a much smaller increase in mean permeability, and the range stays relatively steady — this may be explained by the capillary conditions set up by the smaller volume of the stone, allowing salts to migrate to the ‘back’ of the blocks and effectively relieving stress at the ‘front’ face.

Drivers of sales performance: a contemporary meta-analysis. Have salespeople become knowledge brokers?

It has been 25 years since the publication of a comprehensive review of the full spectrum of salesperformance drivers. This study takes stock of the contemporary field and synthesizes empirical evidence from the period 1982–2008. The authors revise the classification scheme for sales performance determinants devised by Walker et al. (1977) and estimate both the predictive validity of its sub-categories and the impact of a range of moderators on determinant-sales performance relationships. Based on multivariate causal model analysis, the results make two major observations: (1) Five sub-categories demonstrate significant relationships with sales performance: selling-related knowledge (ß=.28), degree of adaptiveness (ß=.27), role ambiguity (ß=-.25), cognitive aptitude (ß=.23) and work engagement (ß=.23). (2) These sub-categories are moderated by measurement method, research context, and salestype variables. The authors identify managerial implications of the results and offer suggestions for further research, including the conjecture that as the world is moving toward a knowledge-intensive economy, salespeople could be functioning as knowledge-brokers. The results seem to back this supposition and indicate how it might inspire future research in the field of personal selling.