14 resultados para 671102 Rail equipment
Resumo:
Drawing on the literature in criminology and media studies on the nature of social understandings of corporate crime and its representation in the media, this paper takes one small but important step in this direction by carrying out a linguistic case study on the news coverage of one sequence of events which resulted from corporate negligence – the Paddington rail crash, a sequence of news events that were important as they led to legal change as regards corporate responsibility in Britain. The paper concludes by showing that while the news coverage played an important part in leading to a change in the law regarding corporate responsibility, although this received little coverage in the press.
Resumo:
Dual-rail encoding, return-to-spacer protocol, and hazard-free logic can be used to resist power analysis attacks by making energy consumed per clock cycle independent of processed data. Standard dual-rail logic uses a protocol with a single spacer, e.g., all-zeros, which gives rise to energy balancing problems. We address these problems by incorporating two spacers; the spacers alternate between adjacent clock cycles. This guarantees that all gates switch in every clock cycle regardless of the transmitted data values. To generate these dual-rail circuits, an automated tool has been developed. It is capable of converting synchronous netlists into dual-rail circuits and it is interfaced to industry CAD tools. Dual-rail and single-rail benchmarks based upon the advanced encryption standard (AES) have been simulated and compared in order to evaluate the method and the tool.
Resumo:
A Design of Experiments (DoE) analysis was undertaken to generate a list of configurations for CFD numerical simulation of an aircraft crown compartment. Fitted regression models were built to predict the convective heat transfer coefficients of thermally sensitive dissipating elements located inside this compartment. These are namely the SEPDC and the Route G. Currently they are positioned close to the fuselage and it is of interest to optimise the heat transfer for reliability and performance purposes. Their locations and the external fuselage surface temperature were selected as input variables for the DoE. The models fit the CFD data with values ranging from 0.878 to 0.978, and predict that the optimum locations in terms of heat transfer are when the elements are positioned as close to the crown floor as possible ( and ?min. limits), where they come in direct contact with the air flow from the cabin ventilation system, and when they are positioned close to the centreline ( and ?CL). The methodology employed allows aircraft thermal designers to optimise equipment placement in confined areas of an aircraft during the design phase. The determined models should be incorporated into global aircraft numerical models to improve accuracy and reduce model size and computational time. © 2012 Elsevier Masson SAS. All rights reserved.
Resumo:
Simulation of disorders of respiratory mechanics shown by spirometry provides insight into the pathophysiology of disease but some clinically important disorders have not been simulated and none have been formally evaluated for education. We have designed simple mechanical devices which, along with existing simulators, enable all the main dysfunctions which have diagnostic value in spirometry to be simulated and clearly explained with visual and haptic feedback. We modelled the airways as Starling resistors by a clearly visible mechanical action to simulate intra- and extra-thoracic obstruction. A narrow tube was used to simulate fixed large airway obstruction and inelastic bands to simulate restriction. We hypothesized that using simulators whose action explains disease promotes learning especially in higher domain educational objectives. The main features of obstruction and restriction were correctly simulated. Simulation of variable extra-thoracic obstruction caused blunting and plateauing of inspiratory flow, and simulation of intra-thoracic obstruction caused limitation of expiratory flow with marked dynamic compression. Multiple choice tests were created with questions allocated to lower (remember and understand) or higher cognitive domains (apply, analyse and evaluate). In a cross-over design, overall mean scores increased after 1½ h simulation spirometry (43-68 %, effect size 1.06, P < 0.0001). In higher cognitive domains the mean score was lower before and increased further than lower domains (Δ 30 vs 20 %, higher vs lower effect size 0.22, P < 0.05). In conclusion, the devices successfully simulate various patterns of obstruction and restriction. Using these devices medical students achieved marked enhancement of learning especially in higher cognitive domains.