Lights, camera and acoustics: Assessing macrobenthic communities at a dredged material disposal site off the North East coast of the UK

This study presents the results of a trial assessment based on a combination of sampling techniques at a dredged material disposal site located off the North East coast of the UK, over 2001 to 2004. The site was surveyed with a high-resolution sidescan sonar system producing a mosaic with 100% coverage of the survey area. Benthic communities and sediments were ground-truthed using a Hamon grab with a video camera. Additionally, the area was also sampled in 2003 with a Sediment Profile Imaging (SPI) camera, which complemented other techniques by providing in situ information on sediment quality, and biogenic activities. An assessment is made of the benefits of combining the results from conventional methods, principally using grab samples, with those from acoustic techniques and optical imaging devices to determine seafloor and macrobenthic conditions. This information has the potential to contribute to the enhancement of routine monitoring programmes within UK waters.     

Modeling and validation of turbocharged diesel engine airpath and combustion systems

The ultimate aim of this study is the development of an engine modeling approach that would facilitate the design of model-based control techniques for diesel engines. This will allow for the development of more generalized, modular control strategies for different engine types and sizes as opposed to the commonly practiced map-based engine control strategies that depend on maps and feedforward control and require lengthy modifications every time a change is made. Also, most engine modeling studies focus on either airpath or combustion systems, treating these models and their validation individually, and not as an integrated system as is actually the case. To address the need for more realistic models suitable for model-based control design, this study develops a combined airpath and combustion model for the engine, using analytical models wherever possible and derives a model with appropriate control inputs and outputs that could be used in a control scheme. The inclusion of the actuator dynamics of the Exhaust gas recirculation (EGR), variable geometry turbine (VGT), and Throttle (THR) valves in the airpath model and the consideration of nonlinearities in the combustion model allow for the development of a more thorough engine model, as well as the validation of subsystems and the whole integrated engine model using a complete World Harmonized Transient Cycle (WHTC). This test cycle finds limited use due to its challenging transients, and yet, is the demanded test cycle for emission regulations nowadays. These are unique aspects of this modeling study, the results of which indicate that the developed engine model could be used in control design and hardware-in-the-loop simulation (HILS) based engine control prototyping.     

Minimum order bang-bang guidance for feedforward obstacle avoidance steering maneuvers of vehicles

In this paper, a new methodology is presented for computing time-optimal obstacle avoidance maneuvers for ground vehicles. Usually, the problem of obstacle avoidance is addressed in two parts. In the first part a path is planned. In the second an appropriately designed vehicle controller tracks the desired path. In view of the fact that the main problem concerning emergency maneuvers remains the development of an optimal control for minimum time and maximum maneuverability — with respect to the slip risk due to saturation of the tire forces — the authors propose an alternative approach. Considering that the time optimal control according to Pontryagin’s Maximum Principle (PMP) is of bang-bang type the investigations concern the minimum order and magnitude bang-bang control for “feedforward” steering maneuvers with the target of minimizing the computation time and simplifying the algorithm. This is accomplished by keeping the basic PMP logic but transforming the computational algorithm from an exact to a least squares control problem. Furthermore, the paper addresses how to solve the problem of guiding the vehicle from a non rest to a rest position. Simulations of obstacle avoidance maneuvers illustrate the performance of the controller.     

An Internal State Variable Model for the Low Temperature Tempering of Low Alloy Steels

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Relationship between lean six sigma, environmental management systems, and organizational performance in the Malaysian automotive industry

In the globalization era, lean initiatives and environmental management systems are increasingly implemented in the automotive industry. The aim of this report is to investigate and perform structural analysis of Lean Six Sigma (LSS) and Organizational Performance (OP). Data were obtained from 252 top management leaders in the Malaysian automotive industry. This report presents the results of the Exploratory Factor Analyses (EFA), Confirmatory Factor Analysis (CFA), and reliability analysis, which are empirically verified and validated. A set of assessment measurements of LSS and OP is expected to be suitable for their characteristics and improve their competitiveness. Thus, the main objective of the analysis was to provide additional insight into the relationship between LSS and OP by examining the effects of ISO 14001 certification as a moderator. The results indicate that ISO 14001 certification does not significantly moderate the relationship between LSS and OP in the Malaysian automotive industry. However, the OP values for ISO 14001 certified companies are higher than those without ISO 14001 certification.     

Application of a thermodynamic model with a complex chemistry to a cycle resolved knock prediction on a spark ignition optical engine

A combination of experimental and numerical methodologies is proposed for the investigation of knocking in spark ignition engines to aid in better understanding the physical and chemical processes that occur and to exploit the capabilities of a developed computational tool. The latter consists of a thermo-fluid dynamics model, which is part of an advanced 1-D fluid dynamics code for the simulation of the entire engine, and a complex chemistry model, which can be embedded into the thermo-fluid dynamics model using the same integration algorithm for the conservation equations and the reacting species. Their mutual interaction in the energy balance will be considered. The experimental activity was carried out in the combustion chamber of an optically accessible, single-cylinder P.F.I. engine equipped with a commercial head. The experimental data consisted of optical measurements correlated to the combustion and auto-ignition processes within the cylinder. The optical measurements were based on 2-D digital imaging, UV visible natural emission spectroscopy and the chemiluminescence of radical species (OH and HCO). The engine parameters, the pressure signals of the related data and optical acquisition are compared on an individual cycle basis in the simulation by running the engine at a constant speed and varying the spark advance from normal combustion to heavy knock conditions.     

Emission analysis of a compressed natural gas directinjection engine with a homogenous mixture

In an era in which environmental pollution and depletion of world oil reserves are of major concern, emissions produced by automotive vehicles need to be controlled and reduced. An ideal solution is to switch to a cleaner fuel such as natural gas, which generates cleaner emissions. In addition, control over the in-cylinder air-fuel mixture can be best achieved through a direct-injection mechanism, which can further improve combustion efficiency. This need for cleaner automobiles provides the motivation for this paper’s examination of the use of computational fluid dynamic (CFD) simulations to analyze the concentrations of the exhaust gases produced by a compressed natural gas engine with a direct-fuel-injection system. In this work, a compressed natural gas direct-injection engine has been designed and developed through a numerical simulation using computational fluid dynamics (CFD) to provide an insight into complex in-cylinder behavior. The emissions analyzed in this study were carbon monoxide (CO), nitric oxide (NO) and carbon dioxide (CO₂), i.e. the main pollutants produced by natural gas combustion. Based on a stoichiometric mixture, the concentrations of CO and NO were computed using the dissociation of carbon dioxide and the extended Zeldovich mechanism. CO₂ was calculated using a mass balance of the species involved in the combustion process. The simulation results were then compared with the experimental data generated by a single-cylinder research engine test rig. A good agreement was obtained with the experimental data for the engine speeds considered for all emissions concentrations.     

An advanced theory of thin-walled girders with application to ship vibrations

The paper presents an outline of the advanced theory of thin-walled girders. The improvement includes shear influence on torsion as an extension of shear influence on bending. The analogy between bending and torsion is recognized and pointed out throughout the paper. Complete differential equations of coupled flexural and torsional vibrations for a prismatic girder are derived. In addition, the 8 d.o.f. beam finite element, utilizing the energy approach, is constituted with stiffness and mass matrices, and load vectors. The paper describes determining of geometrical properties of multi-cell open cross-sections by employing the strip element method. Numerical procedures for vibration analyses are outlined. Furthermore, dry natural vibrations of a VLCS (Very Large Container Ship) are analysed by 1D FEM model as a prerogative for hydroelastic analyses of these relatively flexible vessels. Influence of transverse bulkheads is taken into account by increasing torsional stiffness of the ship hull proportionally to their deformation energies. Validation of 1D FEM model is checked by correlation analysis with the vibration response of the fine 3D FEM model.     

Design of vehicle of on-glass 4×4 MIMO antennas for WiBro applications

This paper proposes on-glass 4×4 MIMO antennas with broad bandwidth and high radiation gain, suitable for receiving WiBro internet applications in a commercial sedan. For the individual antenna body, we used a triangular-shaped patch that most efficiently satisfies broad-matching bandwidth. Then the inside of the triangular patch was partially removed to broaden the driver’s field of view. To obtain detailed design parameters that exhibit optimum radiating performance, we used a genetic algorithm (GA) in conjunction with a full wave EM simulator and varied the feeding locations of four antennas so as to increase throughput capacity for effective data transmission. The proposed antenna showed ?10 dB matching bandwidth and a measured average gain of about 4.77 dBi along the bore-sight direction (θ = 90°, ? = 180°) in the entire WiBro band (2.3–2.4 GHz). To confirm the MIMO performance in a real situation, we measured the commercial WiBro signal using the proposed antennas in an urban environment. The correlation coefficients among the antennas were calculated, and the result revealed an average value of 0.105.     

A numerical study of stochastic larval settlement in the California Current system

Key to the predictive understanding of many nearshore marine ecosystems is the transport of larvae by ocean circulation processes. Many species release thousands to billions of larvae to develop in pelagic waters, but only a few lucky ones successfully settle to suitable habitat and recruit to adult life stages. Methodologies for predicting the larval dispersal are still primitive, and simple diffusive analyses are still used for many important applications. In this study, we investigate mechanisms of larval dispersal using idealized simulations of time-evolving coastal circulations in the California Current system with Lagrangian particles as models for planktonic larvae. Connectivity matrices, which describe the source-to-destination relationships for larval dispersal for a given larval development time course, are used to diagnose the time–space dynamics of larval settlement. The resulting connectivity matrices are shown to be a function of several important time scales, such as the planktonic larval duration, the frequency and duration of larval release events and inherent time scales for the coastal circulations. Many important fishery management applications require knowledge of fish stocks on a year-to-year or generation-to-generation basis. For these short time scales (typically less than 1 year), larval dispersal is generally far from a simple diffusive process and the consideration of the stochastic and episodic nature of larval dispersal is required. This work provides new insights into the spatial–temporal dynamics of nearshore fish stocks.