807 research outputs found
Effects of culture on project management contributing to the success of managing culturally diverse engineering teams in a global environment
Abstract: The research in this paper measured the Cultural Intelligence capability of engineering project leaders and team members from around the world, and their awareness of cultural influences on project management. The focus was on comparing South African engineers to those in other countries. It was concluded that intercultural communication and differences in decision-making were two primary cultural factors influencing the success of managing culturally diverse engineering teams
Identification of suitable areas for multireef operation at Thorncliffe Chrome Mine
Thorncliffe Chrome Mine, one of Glencoreâs Eastern Chrome operations, is currently mining the Middle Group No.1 (MG1) chromitite layer and is conducting a pre-feasibility study for an expansion project to mine the Middle Group chromitite No.2 (MG2) layer. This paper focuses on identifying viable areas within the MG2 layer that adhere to the mining, geological, and rock engineering parameters for a safe multiple-reef operation; and establishing efficient ways of accessing and extracting the MG2 chromitite layer. The findings from the multi-reef project at Samancorâs Tweefontein Mine (Gouvea, 2013) and Maritz (2015) emphasized that the best layout for a safe and stable multi-reef operation is one where pillars are superimposed. The guidelines by Salamon and Oravecz (1976) were key in the selection criteria for pillar stability. A stage gate analysis was used to identify mineable areas using the success selection criteria for mineability obtained from geotechnical and geostatistical analysis of the assay data and isopach plan. During this study, it was found that the most cost-efficient way of accessing the MG2 chromitite layer is from the MG1 mining horizon through a connecting ramp instead of sinking a shaft. Moreover, using the MG1 infrastructure during the development of the MG2 mining horizon will reduce the project development cost. A bord-and-pillar layout with superimposed pillars will assist in reducing the stress concentrations and interactions between the two mining horizons. With all the considerations being satisfied, it can be concluded that the MG2 layer is viable to mine in a safe manner along with the MG1 layer in a multi-reef environment.Paper written on project work carried out in partial fulfilment of B.Eng
(Mining Engineering) degreehttp://www.saimm.co.za/journal-papersam2021Mining Engineerin
Statistical Theory of Spin Relaxation and Diffusion in Solids
A comprehensive theoretical description is given for the spin relaxation and
diffusion in solids. The formulation is made in a general
statistical-mechanical way. The method of the nonequilibrium statistical
operator (NSO) developed by D. N. Zubarev is employed to analyze a relaxation
dynamics of a spin subsystem. Perturbation of this subsystem in solids may
produce a nonequilibrium state which is then relaxed to an equilibrium state
due to the interaction between the particles or with a thermal bath (lattice).
The generalized kinetic equations were derived previously for a system weakly
coupled to a thermal bath to elucidate the nature of transport and relaxation
processes. In this paper, these results are used to describe the relaxation and
diffusion of nuclear spins in solids. The aim is to formulate a successive and
coherent microscopic description of the nuclear magnetic relaxation and
diffusion in solids. The nuclear spin-lattice relaxation is considered and the
Gorter relation is derived. As an example, a theory of spin diffusion of the
nuclear magnetic moment in dilute alloys (like Cu-Mn) is developed. It is shown
that due to the dipolar interaction between host nuclear spins and impurity
spins, a nonuniform distribution in the host nuclear spin system will occur and
consequently the macroscopic relaxation time will be strongly determined by the
spin diffusion. The explicit expressions for the relaxation time in certain
physically relevant cases are given.Comment: 41 pages, 119 Refs. Corrected typos, added reference
Efficacy and safety of three different opioid-based immobilisation combinations in blesbok (Damaliscus pygargus phillipsi)
African wildlife species are increasingly being immobilised with combinations of a low dose of potent opioids combined with
medetomidine and azaperone. The physiological effects of these combinations in comparison to conventional potent opioidazaperone
combinations have scarcely been evaluated. In this cross-over study conducted on eight captive blesbok, we compared
the physiological variables of blesbok immobilised with 2 mg of thiafentanil + 10 mg of azaperone (TA); 0.5 mg thiafentanil +
1.5 mg medetomidine (TM), and 0.5 mg thiafentanil + 1.5. mg medetomidine + 10 mg azaperone (TMA). Thiafentanilâs effects
were antagonised with naltrexone at 10 mg naltrexone per mg thiafentanil, and the medetomidine effects with atipamezole at
5 mg atipamezole per mg medetomidine. The physiological variables were compared between treatment groups using descriptive
statistics and repeated measures ANOVA. The TA combination resulted in the shortest induction and recovery times, higher heart
rates, respiratory rates, PaO2, SpO2, and lower MAP and A-a gradients, but with less muscle relaxation. The TM and TMA combinations
caused marked bradycardia and hypoxaemia. The hypoxaemia was most severe in animals immobilised with TMA, and four of eight
blesbok immobilised had a PaO2 < 35 mmHg at the 10- or 15-minute sampling point. These blesbok were provided supplementary
oxygen, which corrected the hypoxaemia. The TA combinations caused the lowest degree of physiological compromise. All three
combinations were effective for the immobilisation of blesbok, but as the low-dose thiafentanil and high-dose medetomidine
combinations caused marked hypoxaemia, supplementary oxygen is recommended when using these combinations.An American Association of Zoo Veterinarians (AAZV) Wild Animal Health Fund grant and the facility and equipment provided by Wildlife Pharmaceuticals South Africa (Pty) Ltd, and the University of Pretoria.http://www.jsava.co.zaam2024Centre for Veterinary Wildlife StudiesParaclinical SciencesProduction Animal StudiesSDG-03:Good heatlh and well-beingSDG-15:Life on lan
Sub-10ps Monolithic and Low-power Photodetector Readout
Recent advances in photon detectors have resulted in high-density imaging
arrays that offer many performance and cost advantages. In particular, the
excellent transit time spread of certain devices show promise to provide
tangible benefits in applications such as Positron Emission Tomography (PET).
Meanwhile, high-density, high-performance readout techniques have not kept on
pace for exploiting these developments. Photodetector readout for next
generation high event rate particle identification and time-resolved PET
requires a highly-integrated, low-power, and cost-effective readout technique.
We propose fast waveform sampling as a method that meets these criteria and
demonstrate that sub-10ps resolution can be obtained for an existing device.Comment: 12 pages, 20 figures, submitted to NIM
Positive pion absorption on 3He using modern trinucleon wave functions
We study pion absorption on 3He employing trinucleon wave functions
calculated from modern realistic NN interactions (Paris, CD Bonn). Even though
the use of the new wave functions leads to a significant improvement over older
calculations with regard to both cross section and polarization data, there are
hints that polarization data with quasifree kinematics cannot be described by
just two-nucleon absorption mechanisms.Comment: 14 pages, 6 figure
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A multilevel neo-institutional analysis of infection prevention and control in English hospitals: coerced safety culture change?
Despite committed policy, regulative and professional efforts on healthcare safety, little is known about how such macro-interventions permeate organisations and shape culture over time. Informed by neo-institutional theory, we examined how inter-organisational influences shaped safety practices and inter-subjective meanings following efforts for coerced culture change. We traced macro-influences from 2000 to 2015 in infection prevention and control (IPC). Safety perceptions and meanings were inductively analysed from 130 in-depth qualitative interviews with senior- and middle-level managers from 30 English hospitals. A total of 869 institutional interventions were identified; 69% had a regulative component. In this context of forced implementation of safety practices, staff experienced inherent tensions concerning the scope of safety, their ability to be open and prioritisation of external mandates over local need. These tensions stemmed from conflicts among three co-existing institutional logics prevalent in the NHS. In response to requests for change, staff flexibly drew from a repertoire of cognitive, material and symbolic resources within and outside their organisations. They crafted 'strategies of action', guided by a situated assessment of first-hand practice experiences complementing collective evaluations of interventions such as 'pragmatic', 'sensible' and also 'legitimate'. Macro-institutional forces exerted influence either directly on individuals or indirectly by enriching the organisational cultural repertoire
Deep Inelastic Scattering from off-Shell Nucleons
We derive the general structure of the hadronic tensor required to describe
deep-inelastic scattering from an off-shell nucleon within a covariant
formalism. Of the large number of possible off-shell structure functions we
find that only three contribute in the Bjorken limit. In our approach the usual
ambiguities encountered when discussing problems related to off-shellness in
deep-inelastic scattering are not present. The formulation therefore provides a
clear framework within which one can discuss the various approximations and
assumptions which have been used in earlier work. As examples, we investigate
scattering from the deuteron, nuclear matter and dressed nucleons. The results
of the full calculation are compared with those where various aspects of the
off-shell structure are neglected, as well as with those of the convolution
model.Comment: 36 pages RevTeX, 9 figures (available upon request), ADP-93-210/T128,
PSI-PR-93-13, accepted for publication in Physical Review
Physics Opportunities with the 12 GeV Upgrade at Jefferson Lab
This white paper summarizes the scientific opportunities for utilization of
the upgraded 12 GeV Continuous Electron Beam Accelerator Facility (CEBAF) and
associated experimental equipment at Jefferson Lab. It is based on the 52
proposals recommended for approval by the Jefferson Lab Program Advisory
Committee.The upgraded facility will enable a new experimental program with
substantial discovery potential to address important topics in nuclear,
hadronic, and electroweak physics.Comment: 64 page
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