73,405 research outputs found
RISK PREDICTION AND REDUCTION IN PASSENGER TRANSPORT SERVICE DELIVERY
Risk is a phenomenon that has become part of human activities. Risk is in everything and is defined according to the circumstance of the activity or event under contention. Transportation business in Nigeria is a highly risky one especially as it affects passenger transport services. The abundance of bad roads and reckless driving habits coupled with poor highway and vehicle maintenance culture tends to multiply the risk for both operators and their human cargoes. The need to effectively determine operational risk with a view to finding ways of reducing same gave rise to the research and presentation of this paper. In the course of study, records were obtained and analyzed from the offices of the Federal Road Safety
Corps (FRSC) and a prominent luxury bus transport company at Onitsha. The analysis gave informed insight into the causes of road accidents and their risk factors from which a modest risk prediction model was formulated whilst offering useful suggestions on risk reduction strategies. The study also revealed that passenger transportation business operational risk is of two folds – accidental and
financial risk and it is the combination of these two that determines the overall systematic risk of the business
Inherent work suit buoyancy distribution:effects on lifejacket self-righting performance
Introduction:
Accidental immersion in cold water is an occupational risk. Work suits and life jackets (LJ) should work effectively in combination to keep the airway clear of the water (freeboard) and enable self-righting. We hypothesized that inherent buoyancy, in the suit or LJ, would be beneficial for enabling freeboard, but its distribution may influence LJ self-righting.
Methods:
Six participants consented to complete nine immersions. Suits and LJ tested were: flotation suit (FLOAT; 85 N inherent buoyancy); oilskins 1 (OS-1) and 2 (OS-2), both with no inherent buoyancy; LJs (inherent buoyancy/buoyancy after inflation/total buoyancy), LJ-1 50/150/200 N, LJ-2 0/290/290 N, LJ-3 80/190/270 N. Once dressed, the subject entered an immersion pool where uninflated freeboard, self-righting performance, and inflated freeboard were measured. Data were compared using Friedman’s test to the 0.05 alpha level.
Results:
All suits and LJs enabled uninflated and inflated freeboard, but differences were seen between the suits and LJs. Self-righting was achieved on 43 of 54 occasions, irrespective of suit or LJ. On all occasions that self-righting was not achieved, this occurred in an LJ that included inherent buoyancy (11/54 occasions). Of these 11 failures, 8 occurred (73% of occasions) when the FLOAT suit was being worn.
Discussion:
LJs that included inherent buoyancy, that are certified as effective on their own, worked less effectively from the perspective of self-righting in combination with a work suit that also included inherent buoyancy. Equipment that is approved for use in the workplace should be tested in combination to ensure adequate performance in an emergency scenario
Safety in maritime oil sector: Content analysis of machinery space fire hazards
An in-depth study of the practice within the maritime oil industry was undertaken to ascertain safety issues in seafaring vessels. It was more concentrated on the type of accidents that occur in machine spaces of seafaring vessels in this industry. The main focus of the research was streamlined to fire in machinery spaces. The literature review later concentrated on two of such incidences, they are oil spill and fire events. An investigation was done to assess those factors which actually contribute or are in association to fire outbreak. A content analysis methodology was used to investigate the associative relationships to fire outbreak with the aid of NVivo 9.0 software. The investigation focused on 15 key in-depth reports on machinery space incidences which were uploaded into the software. The results indicate that leakages on hot surfaces were the major causes of fire hazards in seafaring vessels. The results from using this methodology also highlighted two more fire hazards that were not so apparent in previous studies. They are generator fire and compressors fire. The results supported other studies about leakages on hot surfaces as a major contributor, but also clearly show that there are other hazardous factors of fire in machinery spaces that require further investigation
Deterrence vs Judicial Error: a Comparative View of Standards of Proof
We argue that the common law standard of proof, given the rules of evidence, does not minimize expected error as usually argued in the legal literature, but may well be efficient from the standpoint of providing maximal incentives for socially desirable behavior. By contrast, civil law's higher but somewhat imprecise standard may be interpreted as reflecting a tradeoff between providing incentives and avoiding judicial error per se. In our model, the optimal judicial system has rules resembling those in the common law when providing incentives is paramount. When greater weight is given to avoiding error, the optimal system has civilian features.Standard of proof, burden of proof, common law, civil law, evidentiary rules
Mid-infrared quantum optics in silicon
Applied quantum optics stands to revolutionise many aspects of information
technology, provided performance can be maintained when scaled up. Silicon
quantum photonics satisfies the scaling requirements of miniaturisation and
manufacturability, but at 1.55 m it suffers from unacceptable linear and
nonlinear loss. Here we show that, by translating silicon quantum photonics to
the mid-infrared, a new quantum optics platform is created which can
simultaneously maximise manufacturability and miniaturisation, while minimising
loss. We demonstrate the necessary platform components: photon-pair generation,
single-photon detection, and high-visibility quantum interference, all at
wavelengths beyond 2 m. Across various regimes, we observe a maximum net
coincidence rate of 448 12 Hz, a coincidence-to-accidental ratio of 25.7
1.1, and, a net two photon quantum interference visibility of 0.993
0.017. Mid-infrared silicon quantum photonics will bring new quantum
applications within reach.Comment: 8 pages, 4 figures; revised figures, updated discussion in section 3,
typos corrected, added referenc
A review of progressive collapse research and regulations
History has demonstrated that buildings designed to conventional design codes can lack the robustness necessary to withstand localised damage, partial or even complete collapse. This variable performance has led governmental organisations to seek ways of ensuring all buildings of significant size possess a minimum level of robustness. The research community has responded by advancing understanding of how structures behave when subjected to localised damage. Regulations and design recommendations have been developed to help ensure more consistent resilience in all framed buildings of significant size, and rigorous design approaches have been specified for buildings deemed potentially vulnerable to extreme loading events. This paper summarises some of the more important progressive collapse events, to identify key attributes that lead to vulnerability to collapse. Current procedures and guidelines for ensuring a minimum level of performance are reviewed and modelling methods for structures subjected to localised damage are described. These include increasingly sophisticated progressive collapse analysis procedures, including linear static and non-linear static analysis, as well as non-linear static pushover and linear dynamic methods. Finally, fully non-linear dynamic methods are considered. Building connections potentially represent the most vulnerable structural elements in steel-framed buildings; their failure can lead to progressive collapses. Steel connections also present difficulties with respect to frame modelling and this paper highlights benefits and drawbacks of some modelling procedures with respect to their treatment of connections
Introduction to Machine Protection
Protection of accelerator equipment is as old as accelerator technology and
was for many years related to high-power equipment. Examples are the protection
of powering equipment from overheating (magnets, power converters, high-current
cables), of superconducting magnets from damage after a quench and of
klystrons. The protection of equipment from beam accidents is more recent,
although there was one paper that discussed beam-induced damage for the SLAC
linac (Stanford Linear Accelerator Center) as early as in 1967. It is related
to the increasing beam power of high-power proton accelerators, to the emission
of synchrotron light by electron-positron accelerators and to the increase of
energy stored in the beam. Designing a machine protection system requires an
excellent understanding of accelerator physics and operation to anticipate
possible failures that could lead to damage. Machine protection includes beam
and equipment monitoring, a system to safely stop beam operation (e.g. dumping
the beam or stopping the beam at low energy) and an interlock system providing
the glue between these systems. The most recent accelerator, LHC, will operate
with about 3 x 10 protons per beam, corresponding to an energy stored in
each beam of 360 MJ. This energy can cause massive damage to accelerator
equipment in case of uncontrolled beam loss, and a single accident damaging
vital parts of the accelerator could interrupt operation for years. This
lecture will provide an overview of the requirements for protection of
accelerator equipment and introduces various protection systems. Examples are
mainly from LHC and ESS.Comment: 20 pages, contribution to the 2014 Joint International Accelerator
School: Beam Loss and Accelerator Protection, Newport Beach, CA, USA , 5-14
Nov 2014. arXiv admin note: text overlap with arXiv:1601.0520
Search for Effect of Influence from Future in Large Hadron Collider
We propose an experiment which consists of drawing a card and using it to
decide restrictions on the running of Large Hadron Collider (LHC for short) at
CERN, such as luminosity, and beam energy. There may potentially occur total
shut down. The purpose of such an experiment is to search for influence from
the future, that is, backward causation. Since LHC will produce particles of a
mathematically new type of fundamental scalars, i.e., the Higgs particles,
there is potentially a chance to find unseen effects, such as on influence
going from future to past, which we suggest in the present paper.Comment: 18pp, comments added, change of title and corrections of main text;
v4:minor typos correcte
- …