Automobile Brakes Research Articles

A comprehensive environmental analysis of heavy metal contamination, ecological risks and health impacts in Ilokun area, Ado-Ekiti, Nigeria

Heavy metal contamination in ecosystems is a global environmental and health concern. This study assessed the ecological and health risks associated with heavy metal pollution in farmland, dumpsite, stream land, and plant roots in Ilokun, Ekiti State, Southwest Nigeria. Samples were collected from different locations and analyzed for levels of heavy metal concentrations of cadmium (Cd), lead (Pb), manganese (Mn), chromium (Cr), copper (Cu), nickel (Ni), and zinc (Zn) using atomic absorption spectrophotometer. Various pollution indices such as enrichment factor, contamination factor, and geo-accumulation index were employed. Ecological risk methods were used to investigate the pollution status, heavy metal sources, and health risks associated with urban soil. The results showed that the concentrations of these metals exceeded permissible levels at most sampling sites, indicating significant contamination of the samples. Manganese, Cu, Pb, and Zn were the dominant metals in our study, and overall, the following trend: Mn > Zn > Cr > Ni > Cu > Pb > Cd. The contamination factor revealed that Cu, Zn showed moderate contamination, and Pb, Ni, and Mn showed high soil contamination. The ecological risk assessment demonstrated that Pb and Ni were associated with high risks due to anthropogenic influences related to coal combustion, vehicle exhausts, and automobile brakes. The findings indicate severe heavy metal media enrichment in the study area, which may lead to adverse ecological effects and health risks.

DEVELOPMENT OF ULTRA CAPACITOR BASED REGENERATIVE BRAKING SYSTEM FOR ELECTRIC VEHICLES

Regenerative braking is a technique for converting a moving vehicle's kinetic energy into usable form while slowing it down. When an automobile brakes violently, it usually emits heat. If we could conserve energy rather than waste it, that would be amazing, right? That's where regenerative braking technology comes in handy, especially for electric vehicles. It stores the wasted energy in a battery or ultra-capacitor, so it can be used later to start or accelerate the vehicle. In our project, we looked at how effective regenerative braking is during both braking and starting modes. We compared starting the motor with a battery, ultra-capacitor, or a combination of both (HESS), and also analyzed how storing energy during braking works with these systems. Although not all of the regenerated energy is reinvested in the battery, the motor acts as a generator, charging the vehicle's battery. To move the vehicle forward, regenerative braking uses the kinetic energy it temporarily stores during deceleration. We used a lithium-ion battery and ultra-capacitor module energy storage system coupled to a BLDC motor via a converter. These brakes help batteries last longer without needing to be charged externally. They enable efficient power transfer during regenerative braking and acceleration. Our project discusses whether regenerative braking increases or decreases efficiency. of state of charge of battery and ultra- capacitor when starting and braking applied in discharging(in running of motor) and charging(in regenerative braking of motor). And also BLDC motor speed control in starting and braking mode. The model is simulated using MATLAB Simulink software. Keywords: Regenerative braking, kinetic energy, electric vehicles, energy storage, battery, ultra-capacitor, starting mode, braking mode, Hybrid Energy Storage System (HESS), efficiency, motor generator

Most automobile brakes emit charged aerosols into the atmosphere

The charges may allow engineers to mitigate the aerosols’ contribution to urban pollution.

Research Progress in Boron-Modified Phenolic Resin and Its Composites.

As one of the most successful modified phenolic resins, boron-modified phenolic resin (BPF) has excellent heat resistance and ablative resistance, good mechanical and wear resistance, and flame retardancy. BPF and its composites can be widely used in areas such as aerospace, weapons and equipment, automobile brakes, and fire retardants. In this review, the current state of development of BPF and its composites is presented and discussed. After introducing various methods to synthesize BPF, functionalization of BPF is briefly summarized. Particular emphasis is placed on general methods used to fabricate BPF-based composites and the heat resistance, ablative resistance, mechanical property, wear resistance, flame retardancy, and water resistance of BPF-based composites. Finally, the challenges of this research area are summarized and its future outlook is prospected.

Intense blue-emitting Yb/Tm-CaSiO3 wollastonite upconversion phosphors

Wollastonite is a naturally occurring mineral with a chemical formula of CaSiO3. Owing to outstanding mechanical, chemical, and thermal stabilities, wollastonites have become one of the most versatile industry minerals for applications in construction materials, cement, plastics, paints and coatings, friction, automobile brakes, ceramic and metallurgical applications to name a few. Despite technological importance, research on functional properties such as photon upconversion in wollastonites is still lacking. In this report, an initiative has been taken to demonstrate ultra-violet, blue, and near-infrared photon upconversion in CaSiO3 wollastonite via Yb and Tm doping. The wollastonite ceramics are synthesized via microwave hydrothermal technique followed up by heat-treatment in air. β-wollastonite (2M) phase in the synthesized samples has been confirmed by X-ray diffraction and a successful doping of Yb3+ and Tm3+ ions in the CaSiO3 lattice has been confirmed by X-ray photoelectron spectroscopy. The most intense phonon band has been observed at 872 cm−1. Upon 980 nm excitation, ultraviolet, intense blue, and near-infrared upconversion emissions as well as downshifting infrared emissions are observed from Tm3+ ions as a result of sensitization by Yb3+. The temporal evolution of the emitting states is studied to understand the emission mechanism. An absolute upconversion quantum yield of the 20Yb/0.5Tm–CaSiO3 sample in the 400–850 nm range is 0.79%.

Noncontact Defect Detection Method of Automobile Cylinder Block Based on SVM Algorithm

Based on the problems encountered in the gateway system, this article developed the SVM algorithm support vector machine auxiliary system based on the function of the hybrid network gateway to help the gateway dynamically adjust its operating status to ensure the stability of the gateway system and the real-time internal data. This paper studies the noncontact defect detection system of automobile cylinder block on the basis of the SVM algorithm. There are many thin holes in the wall of automobile engine cylinder block, the structure is complex, and the processing is easy to deform. In order to solve the problem of deformation of the automobile engine cylinder block during the milling process, this paper uses a combination of simulation and experiment to analyze the clamping deformation and milling deformation during the machining of the top surface of the automobile cylinder block and proposes the control of the milling deformation profile error measure. Aiming at the problems of backward detection technology, low detection efficiency, and low detection accuracy for the detection of defects on the inner surface of the master cylinder of automobile brakes, this paper uses the machine vision technology to choose the noncontact method of measurement. The use of laser nonultrasonic contact systems is not limited to workpieces having regular shapes, such as planes and cylinders. It is limited to workpieces with regular shapes such as planes and cylinders. In the automotive and other industrial fields, for various curved parts with free-form surfaces, nondestructive testing techniques of laser nonultrasonic contact systems are generally required to find defects. In the research of the noncontact defect detection method of the automobile cylinder block based on the SVM algorithm, this paper hopes that the detection efficiency and detection accuracy of the inner surface of the brake cylinder can be improved, and the defect location can be accurately found.

Landfill gas as a source of anthropogenic antimony and arsenic release

Antimony is used extensively in consumer goods, including single use plastic bottles, electronics, textiles and automobile brakes, which are disposed of in landfills at the end of their service lives. As a result, Sb is a constituent of concern in landfill emissions. Previous research has focused on leachate (liquid) and waste incineration flue gas emissions; however, Sb has the potential to volatilize through chemical and microbial processes within a landfill. In this study, iron-amended granular activated carbon was used to adsorb volatile metals directly from gas in a full-scale landfill gas collection system. Metals were quantified using acid digestion and ICP-AES analysis. Antimony concentrations far exceeded those previously reported, at up to 733 μg m−3 (mean: 254 μg m−3). In addition to Sb, As was also measured at high levels compared to previous research, as high as 740 μg m−3 (mean: 178 μg m−3). Using US EPA landfill and landfill gas databases, total Sb emissions via landfill gas are estimated to be approximately 27.3 kg day−1 in the US. Based on other estimates of national and global Sb emissions, this corresponds to approximately 4.5% of total US atmospheric emissions of Sb and 0.42% of global atmospheric emissions. Sb mass release via landfill gas is approximately 3.9 times higher than via leachate emissions. Although gas emissions are higher than expected, the vast majority (99.9%) of Sb present in landfilled MSW remains within the waste mass indefinitely. In addition to these mass release estimates, this experiment suggests that iron-amended activated carbon may offer significant metals removal from LFG, especially in the first months of new well operation.

Enclosure Design for Brake Wear Particle Measurement Using Computational Fluid Dynamics

The harmfulness of fine dust generated by automobile brakes to the environment has recently received attention. Therefore, we aimed to analyze and regulate the brake wear particles in dynamometers. To accurately measure the number of particles and particle mass, the sampling system used needs to minimize transportation losses and reduce the residence time in the brake enclosure system. The brake dust measurement system currently used can estimate the main transportation loss but cannot evaluate the complex flow field in the brake enclosure system under different design conditions. We used computational fluid dynamics (CFD) technology to predict the behavior of brake wear particles and analyze the static pressure characteristics, the uniformity of the system flow, and the residence time of the brake dust particles in the system. In addition, we compared the design of the basic structure of the brake enclosure system, combined with the four factors affecting the design of the brake dynamometer, with the enclosure system. As a result, we proposed that the design of the cross section of the brake dynamometer enclosure should be circular, the outlet angle of the enclosure should be 15°, the caliper should be fixed to 150°, and two sets of splitters should be added. This design improves pressure loss and reduces the residence time of brake dust particles in the brake enclosure system.

Investigation on wear behavior of Al6061 hybrid metal matrix composite in braking applications

The present article investigates the dry sliding wear behavior of Aluminium 6061 hybrid metal matrix composite (ALHMMC) and compare the results with cast iron(ci). The (ALHMMC) possess light weight, low corrosion and high strength which offer unique property, which can use in automobile brakes. The main objective of this work to investigate the sliding wear behavior of al6061 composites reinforce mos2 particles and to optimize the process parameters in braking applications. the composite were prepared by using stir casting technique and optimization were done by using taguchi technique. The optimal combinations input parameters which will positively influence the wear rate and coefficient of friction. Dry sliding wear test method was used to conduct the experiments by using pin-on-disc wear testing machine. design of experiment was selected for analysis of the data. Investigation about applied load, sliding speed, sliding distance on wear rate and coefficient of friction during wearing process was carried out using ANOVA. results show that applied load has the highest influence followed by sliding distance and sliding velocity.

Stick-slip at soft adhesive interfaces mediated by slow frictional waves.

Stick-slip is a friction instability that governs diverse phenomena from squealing automobile brakes to earthquakes. At soft adhesive interfaces, this instability has long been attributed to Schallamach waves, which are a type of slow frictional wave. We use a contact configuration capable of isolating single wave events, coupled with high speed in situ imaging, to demonstrate the existence of two new stick-slip modes. It is shown that these modes also correspond to the passage of slow waves-separation pulse and slip pulse-with distinct nucleation and propagation characteristics. The slip pulse, characterized by a sharp stress front, propagates in the same direction as the Schallamach wave. In contrast, the separation pulse, involving local interface detachment and resembling a tensile neck, travels in exactly the opposite direction. A change in the stick-slip mode from the separation to the slip pulse is effected simply by increasing the normal force. Taken together, the three waves constitute all possible stick-slip modes in low-velocity sliding. The detailed observations enable us to present a phase diagram delineating the domains of occurrence of these waves. We suggest a direct analogy between the observed slow frictional waves and well known muscular locomotory waves in soft bodied organisms. Our work answers basic questions about adhesive mechanisms of frictional instabilities in natural and engineered systems, with broader implications for slow surface wave phenomena.

Advancement in Automobile Brakes

Advancement in Automobile Brakes

Should Mental Health Interventions Be Locally Grown or Factory-Farmed?

Should Mental Health Interventions Be Locally Grown or Factory-Farmed?

A Benchmark to Select Data Mining Based Classification Algorithms for Business Intelligence and Decision Support Systems

DSS serve the management, operations, and planning levels of an organization and help to make decisions, which may be rapidly changing and not easily specified in advance. Data mining has a vital role to extract important information to help in decision making of a decision support system. Integration of data mining and decision support systems (DSS) can lead to the improved performance and can enable the tackling of new types of problems. Artificial Intelligence methods are improving the quality of decision support, and have become embedded in many applications ranges from ant locking automobile brakes to these days interactive search engines. It provides various machine learning techniques to support data mining. The classification is one of the main and valuable tasks of data mining. Several types of classification algorithms have been suggested, tested and compared to determine the future trends based on unseen data. There has been no single algorithm found to be superior over all others for all data sets. The objective of this paper is to compare various classification algorithms that have been frequently used in data mining for decision support systems. Three decision trees based algorithms, one artificial neural network, one statistical, one support vector machines with and without ada boost and one clustering algorithm are tested and compared on four data sets from different domains in terms of predictive accuracy, error rate, classification index, comprehensibility and training time. Experimental results demonstrate that Genetic Algorithm (GA) and support vector machines based algorithms are better in terms of predictive accuracy. SVM without adaboost shall be the first choice in context of speed and predictive accuracy. Adaboost improves the accuracy of SVM but on the cost of large training time.

The Dynamics Simulation of Braking Process on Automobile Disc Brake

For a certain type of automobile disc brakes, brake discs and friction linings were modeled by Pro/E. The dynamics simulations of braking process on disc brake were performed by the frictional contact algorithm and nonlinear finite element method. Distribution of stress, strain and displacement on the brake parts were investigated with different initial velocity. Analysis results shown that redistributions of stress and strain had occurred on the face of brake disc and friction linings in braking process. Meanwhile, the increased initial velocity resulted in increased stress and stain. Besides the stress concentrations appeared in brake disc role and friction lining corners at the beginning of braking, however, stress and stain became uniform along the braking. Analysis results provided the research of the optimum design and testing of disc brake with theoretic gist. And some improvement measures to the structure of disc brake were proposed.

Asbestos Exposures during Reprocessing of Automobile Brakes and Clutches

Asbestos exposures of workers in three small factories reprocessing automobile brakes and clutches in Japan were investigated. Airborne asbestos was collected on a membrane filter using an air sampler. From 1982 to 1989, asbestos counting was performed on 295 samples (198 personal and 97 stationary), using phase contrast microscopy. Only chrysotile asbestos was detected. Workers who reprocessed automobile brakes and clutches were exposed to asbestos concentrations of 0.025-76.4 fibers/cm3. Geometric mean asbestos concentrations during attaching linings to brake shoes and attaching facings to clutch disks were 0.859 fibers/cm3 and 0.780 fibers/cm3, respectively. Concentrations during stripping worn brake linings and clutch facings were 0.484 fibers/cm3 and 0.382 fibers/cm3, respectively. Machine grinding and leveling of new brake-lining surfaces represent potential sources of heavy asbestos exposures, unless enclosures and local ventilation are efficient.

Environmental And Occupational Health Hazards Associated With The Presence Of Asbestos In Brake Linings and Pads (1900 To Present): A “State-of-the-Art” Review

Throughout the history of automobile development, chrysotile asbestos has been an essential component of vehicle brake linings and pads. Acceptable alternatives were not fully developed until the 1980s, and these were installed in vehicles produced over the past decade. This article presents a “state-of-the-art” analysis of what was known over time about the potential environmental and occupational health hazards associated with the presence of chrysotile asbestos in brake linings and pads. As part of this analysis, the evolution of automobile brakes and brake friction materials, beginning with the early 1900s, is described. Initial concerns regarding exposures to asbestos among workers involved in the manufacture of friction products were raised as early as 1930. Between 1930 and 1959, eight studies were conducted for which friction product manufacturing workers were part of the population assessed. These studies provided evidence of asbestosis among highly exposed workers, but provided little information on the magnitude of exposure. The U.S. Public Health Service proposed the first occupational guideline for asbestos exposure in 1938. The causal relationship between asbestos exposure and lung cancer was confirmed in 1955 in asbestos textile workers in the United Kingdom, and later, in 1960, in South Africa, mesothelioma was attributed to asbestos exposure to even relatively low airborne concentrations of crocidolite. Between 1960 and 1974, five epidemiology studies of friction product manufacturing workers were conducted. During this same time period, the initial studies of brake lining wear (dust or debris) emissions were conducted showing that automobile braking was not a substantial contributor of asbestos fibers greater than 5μm in length to ambient air. The first exposure surveys, as well as preliminary health effects studies, for brake mechanics were also conducted during this period. In 1971, the Occupational Safety and Health Administration promulgated the first national standards for workplace exposure to asbestos. During the post-1974 time period, most of the information on exposure of brake mechanics to airborne asbestos during brake repair was gathered, primarily from a series of sampling surveys conducted by the National Institute of Occupational Safety and Health in the United States. These surveys indicated that the time-weighted average asbestos concentrations (about 1–6h in duration) during brake servicing were between 0.004 and 0.28 fibers per cubic centimeter, and the mean time-weighted average concentration was about 0.05 fibers per cubic centimeter. The data also showed that brake mechanics were not exposed to time-weighted average concentrations above workplace exposure limits in effect at the time of the study. From 1975 to 2002, more than 25 epidemiology studies were conducted examining the risks of asbestos-related diseases in brake mechanics. These studies clearly indicated that brake mechanics were not at increased risk of adverse health effects due to exposure to asbestos. Specifically, the studies found no increased risk of mesothelioma or asbestosis in brake mechanics, and no evidence that lung cancer in this occupational group can be attributed to exposure to asbestos during brake repair. This could be due to one or a number of factors: the airborne concentration of chrysotile asbestos and the duration of exposure are too small to be significant, the chrysotile fibers are too short to be biologically important, that chrysotile fibers are substantially less potent than amphibole fibers in inducing lung cancer and mesothelioma, or other yet-to-be-understood factors. Finally, there were 20 studies published during this time period evaluating asbestos exposure or asbestos-related health effects in friction product manufacturing workers. These studies indicated that these workers were historically exposed to concentrations of chrysotile fibers perhaps 10 to 50 times greater than those of brake mechanics, but the risk of asbestosis, mesothelioma, and lung cancer, if any, was not apparent, except for those workers who had some degree of exposure to amphibole asbestos during their careers.

Loading estimates of lead, copper, cadmium, and zinc in urban runoff from specific sources

Urban stormwater runoff is being recognized as a substantial source of pollutants to receiving waters. A number of investigators have found significant levels of metals in runoff from urban areas, especially in highway runoff. As an initiatory study, this work estimates lead, copper, cadmium, and zinc loadings from various sources in a developed area utilizing information available in the literature, in conjunction with controlled experimental and sampling investigations. Specific sources examined include building siding and roofs; automobile brakes, tires, and oil leakage; and wet and dry atmospheric deposition. Important sources identified are building siding for all four metals, vehicle brake emissions for copper and tire wear for zinc. Atmospheric deposition is an important source for cadmium, copper, and lead. Loadings and source distributions depend on building and automobile density assumptions and the type of materials present in the area examined. Identified important sources are targeted for future comprehensive mechanistic studies. Improved information on the metal release and distributions from the specific sources, along with detailed characterization of watershed areas will allow refinements in the predictions.

ブレーキ摩擦材における黒鉛の摩擦特性

Graphite has been used in the friction materials for automobile brakes as a solid lubricant which provider wear resistance of friction materials and maintains smoothness on the frictional surfaces of rotors.In this study, the effects of graphite to frictional characteristics were investigated under conditions similar to those in practical usage by inertia dynamo meter tests.The effects of the concentration and particle size of graphite in the brakes materials on the friction coefficient and amount of wear were evaluated.

Asbestos brake emissions

An enclosed brake-testing machine was built to determine the importance of asbestos emissions from automobile brakes. Higher emissions resulted from disc brakes than from drum brakes due to the smaller surface area contacting the wheel in the former case. Median emissions from one disc brake were 3.3 mg particulate/stop (55% airborne, 12% sedimentary, 34% brake-entrained), 0.6 mg C/stop as hydrocarbons, 0.7 mg C/stop as CO 2, and 0.1 mg C/stop as CO. Higher emissions were observed with increases in velocity and deceleration rate. The mass median aerodynamic diameter of the emitted particles was 3.1 μm. Although the original brake material was about 50% asbestos, the emitted particles averaged only 0.029% asbestos. Therefore, it appears that over 99.9% of the mass of original asbestos fibers was broken down into nonfibrous magnesium silicates. In addition, asbestos fibers which are on the order of millimeters in length in the brake had a median length of 0.5 μm in the emitted debris. Based on the mass emission results and a stopping rate of 1.2 stops/km, it can be estimated that 2.6 μg of asbestos/km/vehicle is emitted into the air, 0.76 μg/km settles to the roadway, and 2.2 μg/km is entrained in the wheel. Although brake emissions are responsible for a minor fraction of ambient asbestos levels, there may be a noticeable increase in asbestos levels near high-braking areas such as tollbooths.

Some Measurements of Brake Usage in a High-Speed Saloon Car

The paper describes equipment which has been developed to record the duties imposed upon automobile brakes in service under various normal conditions. The principal measurement required was the rate of energy dissipation at the brakes, and this was recorded, together with the drum speed and deceleration, on a roll-chart recorder. The principles involved in these measurements are discussed in some detail, together with an outline of the practical precautions necessary to preserve the accuracy of the readings. From the results it will be possible to develop improved testing cycles for the test machines used in the development of brake lining materials but, in addition, some points of fundamental interest have emerged from the investigation. The results quoted in the paper show that the energy dissipated at the brakes is directly related to the mean journey speed for a given journey when other factors are kept constant and that: Energy dissipated at the brakes = (mean journey speed) n where n has a value of about 3.4 for the conditions encountered in this investigation. The effect of mean journey speed is shown to be much greater than that of the other variables considered although it must, of course, be taken in conjunction with the characteristics of the road. Braking in hilly country is shown to be appreciably more severe than on corresponding roads through flat country.