Hydrographic conditions affecting two fishing grounds of Mallorca island (Western Mediterranean): during the IDEA Project (2003–2004)

This paper describes the hydrographic conditions observed during six surveys carried out during 2003 and 2004, in the framework of the “IDEA Project” (acronym for “Influence of oceanographic structure and dynamics on demersal populations in waters of the Balearic Islands”). The surveys were developed on the shelf and slope of Mallorca Island, in particular in two fishing grounds at the north and south of the Mallorca channel. Periodic movements of the fishing fleet between these two areas have been regularly reported, suggesting a seasonal variability of the resources which could be in turn associated with the hydrodynamic variability. With this motivation, water masses affecting these grounds have been identified and their seasonal variability has been studied. Different oceanographic and environmental conditions have been found between the two fishing grounds. These differences are related to the presence of mesoscale structures, associated with the Western Mediterranean Intermediate Water (WIW) at the north of the Ibiza channel and big gyres detached from the Algerian Current. The former has been shown to have influence on the regional oceanic circulation and the latter could affect the progress of fresh Atlantic Water (AW) towards the channels and make possible the presence of high salinity values at intermediate waters at the south of Mallorca Island. Historical data from other oceanographic cruises carried out in the region are finally used to discuss the interannual variability of these mesoscale structures.     

6502站继电器采集故障原因分析

本文通过对6502站继电器采集故障原因进行分析，提出用增加复示继电器、缩短电缆长度或采集电缆单独敷设的方法，减少采集故障发生，确保列控中心识别进路信息采集的正确性。     

Spatial variability of the barotropic M2 constituent tidal current over the Rías Baixas Galician shelf (NW Spain)

Using current meters and systematically repeated vessel mounted ADCP data legs, we describe the role of the semidiurnal and diurnal constituents in the tidal currents and investigate the mesoscale variability of the M₂ tidal currents field along three cross-shelf legs over the Galician shelf. We found that the estimated values of the semi-major axes of the main semidiurnal tidal constituents are closely related to those obtained in previous research and that the tidal currents are predominantly semidiurnal. Amplitudes of the M₂ and S₂ semi-major axes constituents are comparable, and important fortnightly variability should thus be expected in the amplitude of the semidiurnal tidal currents. Vertical profiles of the semi-major axes of the main tidal constituents reveal that, in the absence of stratification, and far from the bottom frictional effects, the tidal currents are mostly barotropic. Over the slope, the tidal ellipses tilt from a north–south orientation toward the northeast–southwest direction and, as we go further into the shelf, their amplitude is increased, a feature that is reasonably explained by the transition from the dynamics of a Poincaré wave offshore to the dynamics of a northward alongshore propagating Kelvin wave over the shelf. The Ría de Vigo exerts a notable influence over the tidal currents, acting as an extension of the shelf and introducing a meridional variation in the orientation of the ellipses from the alongshore direction in the southern straight coast toward the northeast–southwest direction at the latitude of the Rías. Finally, the spatial fitting methods we tried have proved to be successful in VMADCP data detiding in this region.     

Combustion development of a Bi-Fuel engine

Environmental improvement and energy issues are increasingly becoming more important as worldwide concerns. Natural gas is a good alternative fuel that can help to improve these issues because of its large quantity and clean burning characteristics. This paper provides the experimental performance results of a Bi-Fuel engine that uses Compressed Natural Gas as its Primary fuel and gasoline as its secondary fuel. This engine is a modification of the basic 1.4-liter gasoline engine. Generally, on the unmodified base engine, torque and power for CNG fuel are considerably lower than gasoline fuel. In this paper, the influence of fuels on wall temperature, performance and emissions are investigated.     

New approach for performing failure analysis of fuel cell-powered vehicles

Safety of hybrid-electric and fuel cell vehicles is a critical aspect of these new technologies, since any accident exposing occupants of such vehicles to unconventional hazards may result in significant setbacks to successful market penetration. Fuel cell and hybrid-electric drive systems are complex, and it is essential to perform a thorough analysis to determine critical failure conditions. There are several safety concerns for routine operation of such systems, particularly for hydrogen-fueled vehicles. A modified Failure Modes and Effect Analysis (FMEA) has been developed, along with a Criticality Analysis (CrA), to identify potentially hazardous conditions for crash and non-crash situations. A mathematical model of fuel cell operation has been developed and used here in conjunction with the FMEA. Component failures during the event modes are simulated using vehicle models developed with Matlab Simulink tools. Six simulation models were created using the software. In addition, a preliminary finite element model of a fuel cell vehicle, using a Ford Taurus (91′) model year sedan, has been developed and implemented. This finite element model is used as a demonstration of the crash simulation of the vehicle.     

Experimental investigation using CFD for thermal performance of ventilated disc brake rotor

In the present work, different ventilated disc brake rotor configurations were analysed to enhance the heat transfer rate and obtain the uniform temperature distribution in the rotor. CFD code used in this work was validated at using experimental results obtained by conducting experiments on a test rig. The experimental analysis was performed to calculate the mass flow rate and heat dissipation through the rotor. Further, different types of rotor configurations viz. straight radial vane (SRV), tapered radial vane (TRV), alternate long and short vane (ALSV), variable diameter circular pillars (VDCP) were considered for the analysis. A rotor segment of 20° was considered for the numerical analysis due to its rotational symmetry. CFD results were in good agreement with the experiments. The maximum deviation of the numerical results were about 12 % from the experimental results. It is found from the analysis that among the different types of rotor configurations; variable diameter circular pillars (VDCP) rotor gives better rate of heat dissipation with more uniform temperature distribution in the flow passages. Hence for modern high speed vehicles VDCP rotor may be more appropriate.     

Prospects for plug-in hybrid electric vehicles in the United States and Japan: A general equilibrium analysis

The plug-in hybrid electric vehicle (PHEV) may offer a potential near term, low-carbon alternative to today’s gasoline- and diesel-powered vehicles. A representative vehicle technology that runs on electricity in addition to conventional fuels was introduced into the MIT Emissions Prediction and Policy Analysis (EPPA) model as a perfect substitute for internal combustion engine (ICE-only) vehicles in two likely early-adopting markets, the United States and Japan. We investigate the effect of relative vehicle cost and all-electric range on the timing of PHEV market entry in the presence and absence of an advanced cellulosic biofuels technology and a strong (450 ppm) economy-wide carbon constraint. Vehicle cost could be a significant barrier to PHEV entry unless fairly aggressive goals for reducing battery costs are met. If a low-cost PHEV is available we find that its adoption has the potential to reduce CO₂ emissions, refined oil demand, and under a carbon policy the required CO₂ price in both the United States and Japan. The emissions reduction potential of PHEV adoption depends on the carbon intensity of electric power generation. Thus, the technology is much more effective in reducing CO₂ emissions if adoption occurs under an economy-wide cap and trade system that also encourages low-carbon electricity generation.     

城市桥梁改造中的桥头交叉口典型问题及对策

早期桥梁建设中往往对桥头接线缺乏重视,运行至今,存在较多的道路交通问题。文章以福建省将乐县三华大桥桥头交叉口为分析对象,对旧桥改造中面临的一系列道路交通问题进行分析,并结合大桥实际情况,提出了相应的改善措施,供相关工程技术人员参考。