Car Braking Research Articles

Toxic effects of brake wear particles on epithelial lung cells in vitro

BackgroundFine particulate matter originating from traffic correlates with increased morbidity and mortality. An important source of traffic particles is brake wear of cars which contributes up to 20% of the total traffic emissions. The aim of this study was to evaluate potential toxicological effects of human epithelial lung cells exposed to freshly generated brake wear particles.ResultsAn exposure box was mounted around a car's braking system. Lung cells cultured at the air-liquid interface were then exposed to particles emitted from two typical braking behaviours („full stop“ and „normal deceleration“). The particle size distribution as well as the brake emission components like metals and carbons was measured on-line, and the particles deposited on grids for transmission electron microscopy were counted. The tight junction arrangement was observed by laser scanning microscopy. Cellular responses were assessed by measurement of lactate dehydrogenase (cytotoxicity), by investigating the production of reactive oxidative species and the release of the pro-inflammatory mediator interleukin-8. The tight junction protein occludin density decreased significantly (p < 0.05) with increasing concentrations of metals on the particles (iron, copper and manganese, which were all strongly correlated with each other). Occludin was also negatively correlated with the intensity of reactive oxidative species. The concentrations of interleukin-8 were significantly correlated with increasing organic carbon concentrations. No correlation was observed between occludin and interleukin-8, nor between reactive oxidative species and interleukin-8.ConclusionThese findings suggest that the metals on brake wear particles damage tight junctions with a mechanism involving oxidative stress. Brake wear particles also increase pro-inflammatory responses. However, this might be due to another mechanism than via oxidative stress.

Simulation Study of Temperature Field and Stress Field of Disc Brake Based on Direct Coupling Method

In the process of automobile braking, the interaction between the temperature and the dynamic stress of disc brake is a very complex work. In order to simulate this problem accurately, a three-dimensional finite element model was built. Meanwhile the displacement and thermal boundary conditions for solution were determined, in which the coefficient of convection varies with the transient changing of temperature and time. The distributions of stress field and temperature field of the rotor and pads in an emergency braking were analyzed by the direct coupling method. The results of analysis prove that the thermal-structural direct coupling method can simulate the interaction between the stress field and the temperature field more exactly than the axisymmetric method and sequential coupling method do. The changing of stress field is mainly influenced by the temperature field. The results extracted from coupled simulation can give references for the material selection and structural designs in the development of disc brake.

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Simulation of Hydrodynamics Processes of Hydraulic Braking System of Vehicle

The 3D vehicle with the hydraulic braking system and disc brake with the wheel has been investigated. The dynamic models of the disk brake assembly and the wheel have been constructed. The automobile hydraulic braking system consisting of two contours is considered. . The mathematical model of the hydraulic braking system is presented, where the flow of liquid and the interaction of liquid with the rigid bodies are taken into account. The flow of fluid in a hydraulic system is described by a system of equations of a hyperbolic type, which is solved by a characteristics method. During the mathematical simulations and natural experimentations the following results were achieved. The systems of equations of dynamic models’ motions are solved by numerical methods. The dynamic characteristics of the braking system of the automobile are obtained. The results of extreme braking tests and calculations are presented.

An experimental study on the effect of mobile phone conversation on drivers' reaction time in braking response

Introduction This paper presents an experimental study in which the effect of three factors (distance between cars, mobile call duration, and time of driving (day or night)) on drivers' reaction time in braking response was investigated. Methods The experiment was performed in a real driving environment in which 27 male adults between the ages of 22 and 24 years participated. Three levels of the first two factors (i.e., distance between cars and call duration) and two levels of the last factor (i.e., time of driving) were selected to conduct the experimental study. A full factorial design of experiment with 18 treatment combinations and three replicates of each combination were used. Fifty-four trial runs were performed in a random manner and for each run drivers' reaction time in braking response was measured, which served the data for further analysis. Analysis of variance (ANOVA), interaction effect analysis, and various model adequacy tests were carried out using Design Expert software. Results The results of the study indicated that the most important factor affecting the drivers' reaction time in car braking response was the mobile call duration followed by the time of driving, with a high level of interaction between the two factors. It was also found that the distance between cars did not seem to have a significant effect on the reaction time in braking response. It is to be noted that these response times are expected to be higher under normal driving conditions where awareness of experimental environment is not present. Impact on Industry The findings of this study would help mobile phone industries in improving safety of mobile phone users in driving environment.

Controlling over-adjusted process means and variances using VSI cause selecting control charts

Process adjusted unnecessarily is a common problem in statistical process control. Incorrect adjustment of a process may result in shifts in process mean, process variance, or both, ultimately affecting the quality of products. The article considers the variable process control scheme for two dependent process steps with incorrect adjustment. We construct the variable sampling interval (VSI) Z X ¯ - Z S 2 and Z e ¯ - Z S e 2 control charts in order to effectively monitor the quality variable produced by the first process step with incorrect adjustment and the quality variable produced by the second process step with incorrect adjustment, respectively. The performance of the proposed VSI control charts is measured by the adjusted average time to signal (AATS) derived using a Markov chain approach. An example of process control for automobile braking system shows the application and performance of the proposed joint VSI Z X ¯ - Z S 2 and Z e ¯ - Z S e 2 control charts in detecting small and median shifts in mean and variance for the two dependent process steps with incorrect adjustment. The performance of the VSI Z X ¯ - Z S 2 and Z e ¯ - Z S e 2 control charts and the fixed sampling interval (FSI) Z X ¯ - Z S 2 and Z e ¯ - Z S e 2 control charts are compared via the numerical analysis results. These demonstrate that the former is much faster in detecting shifts in mean and variance. Whenever quality engineers cannot specify the values of variable sampling intervals, the optimal VSI Z X ¯ - Z S 2 and Z e ¯ - Z S e 2 control charts are suggested. Furthermore, the impacts of misusing Z Y ¯ - Z S y 2 charts to monitoring the process mean and variance in the second step are also investigated.

ANALYSIS OF CALCULATION METHODS USED FOR ACCURACY EVALUATION OF THE RESULTS OF ROAD ACCIDENT EXAMINATION

For examination of road accidents often calculations are being performed according to mathematical equations having many variables, real values of which are of stochastic nature and they depend on many accident factors. Therefore it is important to know limits of determination of final values of every being analysed parameter of car movement and their probabilistic characteristics. This paper presents some cases of simulation of some road situations by mathematical methods of calculations, which now are widely used for evaluation of accuracy of values of the calculated parameter (in this paper ‐ the braking distance). Also here is presented some analysis of these methods. The paper presents the following cases of car braking: braking with making attempts to prevent a collision with another car, braking through impact‐to‐pedestrian prevention and conventional (rectilinear) car braking. The main attention in the analysis of the mentioned road situations is paid to veracity of the car braking distance, i.e. to limits of variation of values of this parameter and also to influence of accidental factors on the final result which is being looked for. Some conclusions on the expediency of application of the described methods of calculations to analysis of road accidents are present.

Revising the redundancy principle in multimedia learning.

College students viewed a short multimedia PowerPoint presentation consisting of 16 narrated slides explaining lightning formation (Experiment 1) or 8 narrated slides explaining how a car's braking system works (Experiment 2). Each slide appeared for approximately 8-10 s and contained a diagram along with 1-2 sentences of narration spoken in a female voice. For some students (the redundant group), each slide also contained 2-3 printed words that were identical to the words in the narration, conveyed the main event described in the narration, and were placed next to the corresponding portion of the diagram. For other students (the nonredundant group), no on-screen text was presented. Results showed that the group whose presentation included short redundant phrases within the diagram outperformed the nonredundant group on a subsequent test of retention (d = 0.47 and 0.70, respectively) but not on transfer. Results are explained by R. E. Mayer's (2001, 2005a) cognitive theory of multimedia learning, in which the redundant text served to guide the learner's attention without priming extraneous processing.

SKIDMARK PATTERNS AND IDENTIFICATION OF ABS-EQUIPPED PASSENGER CAR

As Anti-Lock Braking System (ABS) was invented to solve the safety problem of tires' lock-up caused by car braking in emergency, its control mechanism might causes the tire-marks produced by ABS car can not be distinguished precisely. This dilemma will distort accident investigation especially on marks and their' identification. To solve this problem, we employ dynamic car-braking test, considering the influential factors on braking under administrable environment, to obtain tire mark observations. The testing results help us to clarify tire marks and develop suitable method to collect investigation data. Furthermore, based on the results, efficient methods on tire marks identification and measurement can be developed and greatly decreases investigation time.

Biomechanical Energy Harvesting: Generating Electricity During Walking with Minimal User Effort

We have developed a biomechanical energy harvester that generates electricity during human walking with little extra effort. Unlike conventional human-powered generators that use positive muscle work, our technology assists muscles in performing negative work, analogous to regenerative braking in hybrid cars, where energy normally dissipated during braking drives a generator instead. The energy harvester mounts at the knee and selectively engages power generation at the end of the swing phase, thus assisting deceleration of the joint. Test subjects walking with one device on each leg produced an average of 5 watts of electricity, which is about 10 times that of shoe-mounted devices. The cost of harvesting-the additional metabolic power required to produce 1 watt of electricity-is less than one-eighth of that for conventional human power generation. Producing substantial electricity with little extra effort makes this method well-suited for charging powered prosthetic limbs and other portable medical devices.

Automobile Braking and Traction Characteristics on the Different Road Surfaces

Abstract The present article depicts the results of the investigation into automobile braking parameters and traction characteristics on the different road surfaces. The results of the investigation into automobile braking (the automobile deceleration and coefficient of traction), while braking in winter conditions, i.e. on ice and snow, are presented. The values of deceleration of the automobile while braking on various non‐typical surfaces, on the asphalt, covered with the motor oil or resin, while driving across the petrol spot, and on other surfaces of the road, are presented. Such data are necessary while modelling the automobile's movement in various road conditions and while carrying out the examination of traffic accidents.

AUTOMOBILE BRAKING AND TRACTION CHARACTERISTICS ON THE DIFFERENT ROAD SURFACES

The present article depicts the results of the investigation into automobile braking parameters and traction characteristics on the different road surfaces. The results of the investigation into automobile braking (the automobile deceleration and coefficient of traction), while braking in winter conditions, i.e. on ice and snow, are presented. The values of deceleration of the automobile while braking on various non‐typical surfaces, on the asphalt, covered with the motor oil or resin, while driving across the petrol spot, and on other surfaces of the road, are presented. Such data are necessary while modelling the automobile's movement in various road conditions and while carrying out the examination of traffic accidents.

EVALUATION OF VERACITY OF CAR BRAKING PARAMETERS USED FOR THE ANALYSIS OF ROAD ACCIDENTS

During the road accident analysis speed of the examined vehicle often is being established in accordance with the length of the trace remained by the vehicle tires. Usually in such case there are values of braking deceleration used for calculations, which are selected from the corresponding references. The real experiment, establishing the braking parameters of the given vehicle, is performed more seldom. In both cases it is important to calculate the vehicle speed in accordance with the received or found values of deceleration as well to estimate the possible limits of the vehicle speed, i.e. to evaluate the veracity of such calculations. This paper presents the results of evaluation of car braking parameters, which are treated as random values in the known probabilistic characteristics.

Using VSI EWMA charts to monitor dependent process steps with incorrect adjustment

The article considers the variable process control scheme for two dependent process steps with incorrect adjustment. Incorrect adjustment of a process may result in shifts in process mean, ultimately affecting the quality of products. We construct variable sampling interval (VSI) EWMAZX and EWMAZe control charts to effectively monitor the quality variable produced by the first process step with incorrect adjustment and the quality variable produced by the second process step with incorrect adjustment. The performance of the proposed VSI control charts is measured by the adjusted average time to signal (AATS) derived using a Markov chain approach. An example of the automobile braking system with incorrect adjustment shows the application and performance of the proposed VSI EWMAZX and EWMAZe control charts in detecting shifts in process mean. Furthermore, the performance of the proposed VSI EWMAZX and EWMAZe control charts and the fixed sampling interval (FSI) EWMAZX and EWMAZe control charts are compared by numerical analysis results. These demonstrate that the former is much faster in detecting small and median shifts in mean. The optimum VSI EWMAZX and EWMAZe control charts are also proposed using optimization technique to minimize AATS when quality engineers cannot specify the values of variable sampling intervals. It has been found that the optimum VSI EWMAZX and EWMAZe control charts always work better than the VSI EWMAZX and EWMAZe control charts.

ANALYSIS OF EMERGENCY BRAKING OF A VEHICLE

In this paper, braking of cars is analyzed: the analytic formulas for description of the said process and the diagrams for its illustration are provided, its mode of operation when the wheels of the car are not blocked is discussed upon, the most important factors that impact it are described herein. The key indicators of braking (such as the settled deceleration, the braking distance, etc.) are discussed upon and their values corrected in experimental way are provided. Their graphical responses and numerical values recommended for calculations bound up with technical experts’ examination of traffic accidents as well as more specifically defined methodologies for them are provided.

DETERMINATION OF THE COSTS ASSOCIATED WITH INHIBITION OF CARS ON HUMPS

The technique of calculation the consumptions of energy for the braking of cars on the sorting humps is offered. The existence of the braking modes with a minimum consumption of energy ensuring a executing the requirements of interval and aiming speed control of a cuts is established.

Adaptive control schemes for two dependent process steps

The article considers the statistical adaptive process control for two dependent process steps. We construct adaptive sample size and sampling interval (ASSI) Z X ¯ and Z e ¯ control charts to monitor the quality variables produced by the first process step and the second process step at the end of the second process step and effectively distinguish which process step is out-of-control. The performance of the proposed ASSI control charts is measured by adjusted average time to signal (AATS) using Markov chain approach. An example of automobile braking system shows the application and performance of the proposed ASSI Z X ¯ and Z e ¯ control charts in detecting shifts in process mean. Furthermore, the performance of the ASSI Z X ¯ and Z e ¯ control charts and the nonadaptive sample size and sampling interval Z X ¯ and Z e ¯ control charts are compared by some numerical analysis results. It demonstrates that the former is much faster than the latter in detecting small shifts in mean.

Adaptive sampling interval cause-selecting control charts

This article considers the statistical adaptive process control for two dependent process steps. We construct an adaptive sampling interval Z X control chart to monitor the quality variable produced by the first process step, and use the adaptive sampling interval Z e control chart to monitor the specific quality variable produced by the second process step. By using the proposed adaptive sampling interval control charts, we can quickly detect and distinguish which process step is out of control. The performance of the proposed adaptive sampling interval control charts is measured by the adjusted average time to signal (AATS), which was derived by a Markov chain approach, for an out-of-control process. An empirical automobile braking system example shows the application and the performance of the proposed adaptive sampling control charts in detecting shifts in process means. Some numerical results obtained demonstrated that the performance of the proposed adaptive sampling cause-selecting control charts outperforms the fixed sampling interval cause-selecting control charts.

Driver-training and emergency brake performance in cars with antilock braking systems

The purpose of this study was to assess the effects of a two-day post-license driver-training program on brake performance in cars with antilock braking systems (ABS). A trainee group ( n = 26) and a control group ( n = 13) participated in the experiment. The trainee group were enrolled in a two-day training course that included instruction in a braking technique that may be used in cars with and without ABS. All participants performed emergency brake tests from 80 and 100 km h −1 in an instrumented car before and after the training period. Results indicated the post-training group used a smoother braking profile, were less reliant on ABS activation, had enhanced postural stability, but took about one car length longer to stop from 100 km h −1 compared with the control group. Implications of these results for braking in cars with and without ABS, and for driver education programs in general are discussed.

Semantic Context Detection Using Audio Event Fusion

Semantic-level content analysis is a crucial issue in achieving efficient content retrieval and management. We propose a hierarchical approach that models audio events over a time series in order to accomplish semantic context detection. Two levels of modeling, audio event and semantic context modeling, are devised to bridge the gap between physical audio features and semantic concepts. In this work, hidden Markov models (HMMs) are used to model four representative audio events, that is, gunshot, explosion, engine, and car braking, in action movies. At the semantic context level, generative (ergodic hidden Markov model) and discriminative (support vector machine (SVM)) approaches are investigated to fuse the characteristics and correlations among audio events, which provide cues for detecting gunplay and car-chasing scenes. The experimental results demonstrate the effectiveness of the proposed approaches and provide a preliminary framework for information mining by using audio characteristics.