Mixed‐mode travel demand forecasting techniques

From an extensive review of literature covering 34 cases where mixed‐mode policies had been used, ranging from strategic area wide to local studies, it was concluded that none of the techniques adopted had adequately dealt with the particular problem of mixed modes.

Two philosophies were identified, a market research approach and formal simulation modelling. The latter ranged from coarse zonal diversion curve models, to individual based multi modal split models. The limited information given in the reports prevented making practical comparisons between the models.

Monte‐Carlo simulation was used in order to look in more depth at the multi‐modal choice model structures encountered in the review. It was found that the multi‐nomial logit, which is the most commonly used model, was quite robust but performed badly when modal costs were highly correlated, a case which may occur far too often.     

Experimental study of the flow induced by a vehicle fan and the effect of engine blockage in a simplified model

Fans are often tested without downstream blockage and, thus, the performance is considerably different when the fan is mounted in a vehicle as part of a cooling system and where high blockage effect is present downstream. The aim of the present work is to analyze by laser Doppler velocimetry LDV measurements the topology of the flow induced by a fan incorporated in a simplified underhood model reproducing engine blockage and to study the blockage effect of the engine positioning on the flow induced by the fan. The distance between the fan and the engine block affects the mean flow axial velocity U. The vertical velocity component W is greatly influenced by the variation of the distance between the fan and the engine block, both in magnitude and topology.     

Benefits and challenges of controlling a LED AFS (adaptive front-lighting system) using fuzzy logic

The vehicular illumination system has undergone considerable technological advances in recent decades such as the use of a Light Emitting Diode (LED) Adaptive Front-lighting System (AFS), which represents an industry breakthrough in lighting technology and is rapidly becoming one of the most important innovative technologies around the world in the lighting community. This paper presents AFS control alternatives using fuzzy logic (types 1 and 2) to determine its operating parameters taking into consideration the road conditions in the state of São Paulo (Brazil). Fuzzy logic is a well-known extension of the conventional (Boolean) logic that enables the treatment of uncertainty present in the information through the definition of intermediary membership values between the “completely true” and the “completely false”. This technique or modeling strategy is particularly important when a multi-parameter decision must be taken or the decisions are based on the human knowledge. The results show the potential of the methodology proposed and its suitability for light control providing safer nighttime driving.     

Marine engineers’ training: Educational assessment for an engine room simulator

Qualitative upgrading of the educational process at university level marine education depends largely on the instructive value of the trainers’ educational software. Marine education software has developed out of a certain initial implementation in an equivalent manner to which the programs of practice and training have been applied in cases of simulations and programming environments. In most cases, educational software categories have developed without taking into consideration any special pedagogical theory.     

Corrosion of working chains continuously immersed in seawater

Chains used in the offshore industry typically are exposed to continued high rates of corrosion, in part due to the working of the chain not permitting a build up of protective rusts. Herein, a procedure is described for estimating the corrosion loss of low-alloy steel chain under continued immersion corrosion conditions. The procedure is based on extensive recent investigations of the effects of water temperature, salinity, water velocity, and surface roughness on steel corrosion under field conditions. Since the working of the chain does not allow corrosion products (rust) to build up on the critical contact surfaces, erosion due to wear and abrasion can be estimated separately. Two example applications are given.     

Driving situations and driver decisions at road traffic signals

Driver performance in responding to the green-amber-red signal change was studied based on a sample of 2316 last crossing and first stopping vehicles collected by unobtrusive observations at 10 junction approaches in Singapore. Two schemes, a speed-distance diagram (S-D) and an acceleration-deceleration (A-D) diagram, were used to demarcate the driving situations; the driver actions, as revealed outcomes of driver decision-making, were mapped onto these diagrams. The speed-distance diagram can give some indication on what a driver would possibly do. The more complicated acceleration-deceleration diagram is useful for diagnosing the appropriateness of the driver actions. An application of the A-D diagram was demonstrated, and several situations prone to red-running were noted.     

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.     

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

QuanitativelyaccuratePredictionsofquenchinduceddistOnionandresidualstressrelyontheabilitytopredictthemicrosthectUralevolUtionthroughOutthequenchProcess.InlowaIloysteels,cUrrenresearchMshavefOcusedontheformationldneticsoffetrite,pearlite,bainiteandmartensite.However,temPeringcanhavealargeinfluenceondistOnionandresidualstrCss,andeffortstoaccountforthislagbehindthemodelingofthePrimnyphasetransihons.AsafirststeptowardsaccountingfortemPerillg,wehavedevelOpedanintemalstatevariablemodelthatuses…     

Design,manufacturing and evaluation of glass/polyester composite crash structures for lightweight vehicles

The development and validation of a modular composite impact structure is presented in the present paper. Quasi-static and dynamic impact tests of the composite components and a full frontal crash test of a vehicle prototype with composite impact structures manufactured by a new UV-pultrusion process have been performed. The results have demonstrated the feasibility of composite impact structures for crash applications with high specific energy absorption values compared with current metallic crash structures. Furthermore, due to the high production capacity of this new manufacturing process, cost-effective composite impact structures for mass-production of conventional cars may be feasible. Finally, a multimaterial numerical model as design tool for crashworthiness applications has also been validated. Different accelerations measured in the crash test have been accurately predicted as well as the crash behaviour of the composite impact structures.