147 research outputs found
Recommended from our members
Flow of granular materials down an inclined plane
The mechanics of flowing granular materials such as coal, sand, fossil-fuel energy recovery, metal ores, etc., and their flow characteristics have received considerable attention in recent years because it has relevance to several technological problems. In a number of instances these materials are also heated prior to processing, or cooled after processing. The governing equations for the flow of granular materials taking into account the heat transfer mechanism are derived using the continuum model proposed by Rajagopal and Massoudi (1990). For a fully developed flow of granular materials down an inclined plane, these equations reduce to a system of coupled ordinary differential equations. The resulting boundary value problem is solved numerically and the results are presented. For a special case, it is possible to obtain an analytic solution; this is given in the Appendix A of this report
Educating Future Environmental Health Professionals
Future environmental health problems will require a new generation of educated and trained professionals. Efforts to enhance the environmental public health workforce have been promoted by several organizations. While progress has been measured by these organizations, many environmental health academic programs are experiencing budget reductions and lower enrollments. One of the reasons for this trend is the so-called higher education crisis. We argue that training is not equivalent to education in the environmental health sciences, albeit the two terms are often used interchangeably. Organizations involved with the education, training, and credentialing of environmental health professionals must work together to ensure the viability and effectiveness of environmental health academic programs
Extending the nomological network of wellness at work
Modern-day organisations face rapid and continuous change. In order to deal with this rapidly changing and current hostile economic environment, most organisations have become increasingly dependent on a healthy and engaged workforce. As a result of the direct and indirect organisational costs associated with work wellness, the total well-being of the individual worker has become the focal point of many organisational interventions. Although work wellness is a multifaceted and continuously evolving concept, most studies have adopted either a pathological or a salutogenic (positive) perspective when examining the construct. Congruent with current thinking in vocational psychology, a balanced model of work wellness was conceptualised in this study, containing both salutogenic (work engagement) and pathological (burnout) constructs. Strong empirical support was found for the proposed balanced model of work wellness based on data collected from a sample of 854 employees working across various sectors of the South African economy.DHE
Thixotropy in macroscopic suspensions of spheres
An experimental study of the viscosity of a macroscopic suspension, i.e. a
suspension for which Brownian motion can be neglected, under steady shear is
presented. The suspension is prepared with a high packing fraction and is
density-matched in a Newtonian carrier fluid. The viscosity of the suspension
depends on the shear rate and the time of shearing. It is shown for the first
time that a macroscopic suspension shows thixotropic viscosity, i.e.
shear-thinning with a long relaxation time as a unique function of shear. The
relaxation times show a systematic decrease with increasing shear rate. These
relaxation times are larger when decreasing the shear rates, compared to those
observed after increasing the shear. The time scales involved are about 10000
times larger than the viscous time scale and about 1000 times smaller than the
thermodynamic time scale. The structure of the suspension at the outer cylinder
of a viscometer is monitored with a camera, showing the formation of a
hexagonal structure. The temporal decrease of the viscosity under shear
coincides with the formation of this hexagonal pattern
The moderating role of personality in the job strain process: A latent interaction approach
Orientation: Most stress models emphasise the impact of adverse work conditions on psychological strain. Despite considerable support for these additive models, the role of personal characteristics moderating the stress–strain sequence is under-researched.
Research purpose: The study investigated the indirect and curvilinear effects of personal resources on the stress–strain sequence.
Motivation for the study: Personal agency may play an important role in changing work conditions, through job crafting and other pro-active work activities. This study’s results may enhance popular work strain models through the incorporation of personal characteristics
Research approach/design, and method: The study made use of a cross-sectional and ex post facto research design and convenience sampling of 879 South African employees across various industries and job levels. The data were collected through a quantitative survey and analysed using latent interaction analysis.
Main findings: Broad support was found for the buffering role of sense of coherence on the relationship between job demands and cynicism, and between job demands and exhaustion.
Practical/managerial implications: The results suggest that the existence of resource-rich environments alone may not be enough to guarantee thriving and engaged employees. The motivating potential of resources is enhanced when employees experience a certain degree of challenge in their work.
Contribution/value-add: The study makes a theoretical contribution by highlighting the importance of personality traits as buffers in the stress–strain sequence. Moreover, latent interaction analysis is seldom used in structural equation modelling, despite holding numerous benefits compared to moderated regression analysis
- …