A wind tunnel investigation into the effects of roof curvature on the aerodynamic drag experienced by a light goods vehicle

Roof curvature is used to increase ground vehicle camber and enhance rear-body boat-tailing to reduce aerodynamic drag. Little aerodynamic data is published for light goods vehicles (LGVs) which account for a significant proportion of annual UK licensed vehicle miles. This paper details scale wind tunnel measurements at Re = 1.6 × 106 of a generic LGV utilising interchangeable roof panels to investigate the effects of curved roof profile on aerodynamic drag at simulated crosswinds between -6° and 16°. Optimum magnitudes of roof profile depth and axial location are suggested and the limited dataset indicates that increasing roof curvature is effective in reducing drag over a large yaw range, compared to a flat roof profile. This is primarily due to increased base pressure, possibly from enhanced mixing of longitudinal vortices shed from the rear-body upper side edges and increased turbulent mixing in the near-wake due to the increased effective boat-tail angle

Investigation of the aerodynamic characteristics of a lifting body in ground proximity

The use of cambered hull shapes in the next generation of lighter-than-air vehicles to enhance aerodynamic performance, together with optimized take-off manoeuvre profiles, will require a more detailed understanding of ground proximity effects for such aircraft. A series of sub-scale wind tunnel tests at Re = 1.4 x 106 on a 6:1 prolate spheroid are used to identify potential changes in aerodynamic lift, drag and pitching moment coefficients that are likely to be experienced on the vehicle hull in isolation when in close ground proximity. The experimental data is supported by a preliminary assessment of surface pressure changes using a high order panel method (PANAIR) and RANS CFD simulations to assess the flow structure. The effect of ground proximity, most evident when non-dimensional ground clearance (h/c) < 0.3, is to reduce lift coefficient, increase drag coefficient and increase the body pitching moment coefficient

The Reinstated Steel Trigger Price Mechanism: Reinforced Barrier to Import Competition

Early in 1978 the Carter Administration implemented a trigger price mechanism (TPM) to aid the distressed United States steel industry. Although the TPM by its terms is a monitoring system, the controversy it has aroused suggests that its actual function extends far beyond mere monitoring of steel imports. Part I of this Comment will examine the TPM in the context of world steel trade to show how the original system actually functioned, and how the new version is likely to operate. Part II will explore the ways in which this import relief program is inconsistent with traditional United States trade law and policy

The Reinstated Steel Trigger Price Mechanism: Reinforced Barrier to Import Competition

Early in 1978 the Carter Administration implemented a trigger price mechanism (TPM) to aid the distressed United States steel industry. Although the TPM by its terms is a monitoring system, the controversy it has aroused suggests that its actual function extends far beyond mere monitoring of steel imports. Part I of this Comment will examine the TPM in the context of world steel trade to show how the original system actually functioned, and how the new version is likely to operate. Part II will explore the ways in which this import relief program is inconsistent with traditional United States trade law and policy

Mesenchymal stem cells to augment therapeutic angiogenesis in hind-limb ischemia models: how important is their source?

Murine models of hind-limb ischemia are frequently used to assess interventions aimed at improving therapeutic angiogenesis in critical limb ischemia. Much of the current focus of angiogenesis lies with mesenchymal stem cells (MSCs). Important considerations when using these models include the strain of mouse, because some strains recover from ischemia more rapidly than others, and the MSC source. MSCs derived from certain strains generate increased levels of growth factors such as vascular endothelial growth factor. This may significantly affect the limb?s ability to generate collateral vessels

Recognizing a Something When Your Library Sees It

AbstractAdvances are needed in random-display technologies to more tightly link drug actions and functions to the genes that control physiological processes. The reports discussed here explore two sides of these issues—generating new library formats and identifying the targets of drug ligands

A Theory of the Relationships between Cognitive Requirements of Computer Programming Languages and Programmers’ Cognitive Characteristics

This paper formulates a theory that investigates the possible effects of two human cognitive characteristics, on the difficulties of learning specific programming languages. The two human cognitive characteristics are Piaget’s cognitive development and McCarthy’s cognitive hemispheric style. This paper consolidates prior research and accepted cognitive theory. It then presents a formulation of a theory that relates cognitive requirements of different computer programming languages and programmers’ cognitive characteristics. If the cognitive requirements for a programming language are beyond the cognitive characteristics of a programming student, the student may burn out. If the cognitive requirements are below the student’s cognitive characteristics the student may be bored. If they are similar to them, the student is able to meet the challenges. Motivation, interest, self-esteem and success may thus be optimized. Different programming languages are more suited for different cognitive characteristics. This theory extends prior research in cognitive theory and cognitive requirements of computer programming