Ming-Chang Jeng

Driver Fatigue and Highway Driving: A Simulator Study

Long duration of driving is a significant cause of fatigue-related accidents on motorways or major roadways. The fatigue caused by driving for extended periods acutely impairs driver alertness and performance and can compromise transportation safety. This study quantitatively measured the progression of driver fatigue and identified the conservative safe duration of continuous highway driving. Thirty young male subjects were analyzed during 90 min of laboratory-simulated highway driving. Sleepiness ratings (SSS) and reaction time (RT) tests were used to assess impairment of driver alertness and vigilance. Additionally, various measures of driving performance recorded throughout the experiment were used to measure temporal deterioration of driver performance from alert to fatigued using principal component analysis (PCA). The analytical results revealed that SSS scores, reaction times (RTs) and unstable driving performance significantly increased over time, indicating that excessive driving time is a significant fatigue factor and potential cause of fatigue-related accidents. Moreover, the analytical results indicated that 80 min was the safe limit for monotonous highway driving. Based on the experimental findings of this study, public awareness of the adverse affects of driver fatigue during long-distance driving should be enhanced. This study provides explicit information of fatigue development that can be used to prevent fatigue-related accidents.

Survival hazards of road environment factors between motor-vehicles and motorcycles

Motorcycles are frequently used in middle- and low-income societies. They are often involved in crashes, and account for a noticeable percentage of fatalities secondary to crashes. Comparing motor-vehicle occupants and motorcycle riders, the present study examined the survival hazard of crash injuries with respect to road environmental factors (i.e., area, road type, and location). We investigated the effects of such factors on survival and survival time after crashes via a binary logistic regression analysis and a Cox proportional hazard regression analysis, respectively. Results indicated that, for both motor-vehicle occupants and motorcycle riders, the fatal prevalence, occurrence likelihood, and risk based on time were decreased in urban areas and elevated on highways. The three indexes were also higher for motor-vehicle occupants on non-straight or non-level roadway sections. The prevalence of death on local roads and at intersections was relatively higher for motorcycle riders compared to motor-vehicle occupants. Speed may contribute to the survival hazard with respect to road environment factors. Speed management initiatives account for hazardous roadway, curve alignment re-examination, and increased traffic enforcement density are suggested. Collaboration among the roadway authorities, vehicle industry, and medical systems for a timely rescue is also advised. In addition, the attention to crashes at intersections and on local roads is a promising intervention for motorcycle riders.

Differences in urban and rural accident characteristics and medical service utilization for traffic fatalities in less-motorized societies.

INTRODUCTION Fatalities from traffic accidents in less-motorized societies are an important global issue. We aimed to characterize the geographic differences of fatalities in such societies to facilitate the development of targeted interventions. METHOD This study linked police reports, hospital data, and vital registration data from Taiwan with special reference to accident factors in pre-hospital deaths and medical care in hospital deaths. RESULTS A higher percentage of pre-hospital deaths were observed following rural as compared to urban traffic accidents. The deaths due to rural accidents can be attributed to lower use of restraints (i.e., helmets or seat belts), lower percentage of motorcyclists, and more highway accidents. A higher percentage of victims in rural accidents were transported to distant medical centers rather than to local hospitals. CONCLUSION Specific interventions, such as intelligent emergency medical systems, campaigns for helmets and seat belt usage, enforcement of helmets and seat belt use, and speed control measures should be targeted to rural areas. IMPACT ON INDUSTRY Cooperation between the vehicle industry and emergency medical providers in rural traffic accident rescue teams may decrease the numbers of deaths in these regions.

Mechanical properties of gas-assisted injection moulded PS, PP and Nylon parts

Abstract PS, PP and Nylon plate parts designed with gas channels having five different types of cross-section but with same section area were gas-assisted injection moulded (GAIM). Mechanical properties of GAIM parts were investigated via tensile and bending tests. Effects of part thickness, shape and associated dimensions of gas channels on tensile and bending properties of GAIM parts were examined. It was found that maximum tensile load and ultimate tensile stress show only slight influence from gas channel design and part thickness except Nylon parts which exhibit significant dependence on part thickness due to degree of crystallinity. Gas channel design, introducing additional moment of inertia, results in part structural reinforcement. Part stiffness and maximum bending load basically increases linearly with the moment of inertia and the section modulus of the plate, respectively. Gas channel design attached with top rib (shapes D and E) show the best effect of structural reinforcement. For brittle PS parts, plates with semicircular gas channel (shape A) exhibit maximum flexural strength. PS parts with rectangular gas channel design (shape B) can absorb more bending energy than the other designs. The present study provides part designers with a design guideline for choosing the most effective gas channel design to achieve a specific objective of part structural performance.

Wear behaviour of solid lubricants Ag and BaF2-CaF2 obtained by laser surface cladding

Abstract The solid lubricants Ag and BaF 2 -CaF 2 eutectic with bond coat Cr 3 C 2 -(Ni-Al) were successfully coated onto AISI 1020 low carbon steel by laser surface cladding via the pre-placing method. The frictional and wear properties of single- and multiple-component lubricants were evaluated at various temperatures (50, 300 and 550°C) with a Schwingung Reibung Verschleiβ (SRV) oscillation friction wear tester under different loads (10, 20 and 30 N). Scanning electron microscopy was used to characterize the wear mechanisms of the worn surfaces of specimens. The results showed that the specimens underwent a loss and that the diameter of their counterpart balls increased with increasing test temperature. The friction coefficient decreased with increasing load. The wear mechanism was studied by observing worn surfaces using scanning electron microscopy which showed that the abrasive wear due to the ploughing of wear debris was significant. The specimen D, which contained 15wt.% Ag and 15wt.% BaF 2 -CaF 2 eutectic in a metal-bonded Ni-Al and Cr 3 C 2 matrix, has the best frictional and wear performance at 300 and 550°C.

Wear behaviour of cobalt-based alloys in laser surface cladding

Abstract The wear properties and wear mechanism of Stellite No. 6 powder cladded over AISI 1020 low carbon steel have been investigated. The wear resistance of specimens with laser surface cladding overlapping by different amounts (20%, 30% and 50%) was measured using a dry-sand rubber-wheel abrasion test and a block-on-ring wear test at room temperature. Wear tests were also performed at different temperatures (50 °C, 150 °C, 250 °C and 400 °C) with an Schwingung reibung verschleis (SRV) oscillation friction wear tester under 25 N and 50 N loads. The specimen with 50% overlapping showed the lowest initial wear, together with the highest surface hardness and a smoother surface than the others. The specimen with 50% overlapping also suffered the lowest total weight loss. Weight loss increased with increasing test temperature up to 150 °C, and then decreased with further increases in temperature owing to transfer of material. The average friction coefficient was about the same for all the overlapping ratios at 50 °C. At 150 °C it had a slightly higher value. The wear mechanism was studied by observing worn surfaces through scanning electron microscopy which showed that the surface polish, plastic deformation and ploughing caused by abrasive wear were very significant at 50 °C. Microcracking, fatigue delamination and brittle fracture could also be observed at temperatures above 250 °C.

Thermohydrodynamic Analysis of the Misaligned Conical-Cylindrical Bearing with Non-Newtonian Lubricants

This work studies the lubrication of a conventional finite diameter conical-cylindrical bearing using a power-law, non-Newtonian lubricant. Thin fluid-film included thermal effects and a modified Reynolds equation are the basic assumptions of this analysis. The film viscosity is taken to be an exponential function of temperature. The performance characteristics of the conical-cylindrical bearing with slenderness ratio ns = 0.8 are also studied, in which the outlet film thickness ratio ℏo = 0.8, for various values of non-Newtonian power-law index n ranging from 0.6 to 1.2, eccentricity ratio ē ranging from 0 to 0.6, misalignment factors σ1 ranging from 0 to 0.6 and σ2 is 0.05. Simulation results indicate that the normal load carrying capacity is enhanced by higher values of flow behavior index n, higher eccentricity ratios and larger misalignment factors. Presented as a Society of Tribologists and Lubrication Engineers Paper at the ASME/STLE Tribology Conference in Cancun, Mexico October 27–30, 2002

Development of a Virtual Simulation System for Crane-Operating Training

The purpose of this work is to develop a virtual simulation system for crane-operating training. It includes an operating chamber to simulate the driving chamber of a truck crane and a motion chair to offer additional vibrating effect. The virtual scenes, generated by a VR software, is displayed on a screen in front of the operating chamber through a 3D projector. A data communication structure is proposed to deliver the information among three personal computers. The hardware configuration of the simulator is discussed and the VR techniques used to generate the virtual scenes are addressed. A performance evaluation in terms of the frame rate is provided also.Copyright

Integrated model of simulated occupant injury risk and real medical costs

INTRODUCTION The purpose of this study was to develop an integrated methodology that links occupant injury risk functions, estimated in the laboratory, with real world medical treatment costs by using the abbreviated injury score (AIS). Using our model, the expected medical treatment costs for crash injuries to various body regions and of different severities can be investigated. METHODS First, the simulation results are compared with NHTSA crash data. We used a modified kinematics simulation model that incorporates an F=E(b) function as a supplement to the previous Steffans model to obtain a more accurate acceleration history a(t). Second, head injury criteria HIC(36) can be calculated from a(t), and we use the injury probability P as a function of HIC(36,) as proposed by Kuppa, to obtain the injury risk function for various AIS values. Third, medical treatment cost models for various AIS values can be calculated by using a regression cost model with real world data. Finally, the injury risk function and medical treatment cost models are linked through AIS values. We establish an integrated methodology and predict medical costs and car safety data using real world police reports, medical treatment costs, and laboratory simulation results. RESULTS Using head injuries in frontal crashes as an example, we focus on simulation parameters for different vehicle models, with and without airbags. We specifically examine impact closing speed, Delta-V, and impact directions. CONCLUSION Simulation results can be used to supplement insufficient real crash data, in particular DeltaV, and injury risk results from police crash reports. IMPACT ON INDUSTRY The proposed integrated methodology may provide the vehicle industry with a new safety assessment method. Real crash data coupling provides consumers with more realistic and applicable information.

Mortality Burden From Motor Vehicle Accidents in Taiwan

OBJECTIVE To examine the risk factors contributing to the mortality burden due to road traffic accidents (RTA) in Taiwan. DESIGN We compared RTA years of life lost (YLL) rates of Taiwan with those of the surrounding region. We also investigated the risk factors described by the police in a Linked Database combined from police-reported accident data and vital registration data. SAMPLE RTA deaths (3,234 males/1,160 females) in vital registration data and the deaths (2,918 males/1,063 females) in the Linked Database were used. MEASUREMENT YLL and YLL rate. RESULTS (1) YLL rates for 15-29 year olds were the highest for Taiwan and the surrounding region. (2) The YLL rate was remarkably high in the first 2 years of the legal motorcycle licensing age for males riding motorcycles. (3) The YLL rates were usually higher during the day, but were higher for young males at night. (4) Overall, the YLL rates were higher when multiple vehicles were involved and for motorcycles with large engines; however, the rate was higher for motorcycles with small engines for the older female group. CONCLUSIONS The burden due to premature mortality in RTA showed gender disparities and varied by age among personal, environment, and structure factors.