Influence of Silica Sand Particles on Disc Brake Squeal Noise

2013 ◽  
Vol 471 ◽  
pp. 81-85 ◽  
Author(s):  
Ahmad Razimi Mat Lazim ◽  
Abd Rahim Abu Bakar ◽  
Mohd Kameil Abdul Hamid ◽  
Izzat Mohd Asri
Keyword(s):  
Surface Condition ◽  
Surface Characteristics ◽  
Silica Sand ◽  
Brake Pad ◽  
Brake Squeal ◽  
The Road ◽  
Film Distribution ◽  
Before And After ◽  
Sand Particles ◽  
On The Road

Researchers in recent years begin to explore on tribological behavior of automotive brake squeal phenomena which covers the morphology, chemical composition, friction and wear, phase composition and third body or friction film distribution. However less effort has been made to study the tribological on the influence of small particles on brake squeal. During braking condition, both rotor and pads are exposed to road environmental particle which may affect pads surface condition. In order to assess the influence of this particle on brake squeal a series of squeal tests were performed. Silica sand grit particles with a size range between 400 to 200 μm which most available on the road surface were used in this experiment. Brake pad and disc surface characteristics were analyzed before and after squealing condition using Scanning Electron Microscope (SEM) and Energy dispersive X-ray analysis (EDX). The result shows that the silica sand particles had influence the squeal and surface behavior of the brake pad.

scholarly journals Measures to optimize traffic and the environment. Calculations of environmental safety on a given section of the Rostov-on-Don road network

2020 ◽  
pp. 68-77
Author(s):  
R. S. Durov ◽  
◽  
E. V. Varnakova ◽  
K. O. Kobzev ◽  
◽  
...  
Keyword(s):  
Road Network ◽  
Road Transport ◽  
Environmental Safety ◽  
Environmental Indicators ◽  
Nox Emissions ◽  
The Road ◽  
Before And After ◽  
Reduce Emissions ◽  
On The Road ◽  
State Of The Environment

Introduction. One of the most pressing socio-economic problems is the state of the environment, which affects the living conditions of many people. The article deals with the problem areas of the intersection of 20-ya Liniya street – Sholokhov Avenue in Rostov-on-Don. Problem Statement. The purpose of this paper is to improve environmental safety at the intersection of 20-ya Liniya street – Sholokhov Avenue in Rostov-on-Don by reducing emissions from road transport through the proposed measures to reorganize traffic on this section of the road network. Theoretical Part. The article provides an assessment of environmental and road safety on the road network section before applying the proposed measures. The measures are listed and justified that would help improve the conditions for road transport at the selected intersection and reduce emissions from road transport, which would improve environmental safety. The calculation of environmental indicators was made after the proposed measures to reduce NOx emissions by cars. Conclusion. The article analyzes the environmental indicators before and after the events, and then compares them. Based on the analysis and calculations, it is determined how much the proposed measures to optimize traffic will help reduce NOx emissions by cars.

Occurrence and Prevention of Changes in the Chemical Structure of Natural Rubber Tire Tread Vulcanizates during Service

1970 ◽  
Vol 43 (5) ◽  
pp. 1215-1224 ◽  
Author(s):  
J. I. Cunneen ◽  
R. M. Russell
Keyword(s):  
Chemical Structure ◽  
Main Chain ◽  
Heavy Duty ◽  
Structural Alterations ◽  
The Road ◽  
Rubber Tire ◽  
Before And After ◽  
On The Road ◽  
The Stability ◽  
Made In

Abstract The chemical structure of the tread vulcanizate of heavy-duty tires has been investigated before and after service on the road, and after testing under conditions designed to induce tread-lift. Significant changes occurred. These included a marked reduction in the concentration of polysulfide crosslinks, and an increase in the amount of monosulfide crosslinks and main chain modification. Experiments with vulcanizates made in the laboratory indicated that the structural alterations in the tires were due to thermal anaerobic reactions caused by heat build-up, and that they resulted in a deterioration in some of the physical properties of the tread vulcanizate. The rate of desulfuration of ‘model’ polysulfides has been found to depend critically upon the nature of the vulcanization recipe. These novel findings point the way to improving the stability of vulcanizates used in the treads of tires and, consequently, tire performance.

scholarly journals Road Surface Condition Forecasting in France

2009 ◽  
Vol 48 (12) ◽  
pp. 2513-2527 ◽  
Author(s):  
L. Bouilloud ◽  
E. Martin ◽  
F. Habets ◽  
A. Boone ◽  
P. Le Moigne ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Initial Conditions ◽  
Meteorological Data ◽  
Surface Condition ◽  
Road Surface ◽  
Snow Layer ◽  
Surface Conditions ◽  
The Road ◽  
Road Surface Temperature ◽  
On The Road

Abstract A numerical model designed to simulate the evolution of a snow layer on a road surface was forced by meteorological forecasts so as to assess its potential for use within an operational suite for road management in winter. The suite is intended for use throughout France, even in areas where no observations of surface conditions are available. It relies on short-term meteorological forecasts and long-term simulations of surface conditions using spatialized meteorological data to provide the initial conditions. The prediction of road surface conditions (road surface temperature and presence of snow on the road) was tested at an experimental site using data from a comprehensive experimental field campaign. The results were satisfactory, with detection of the majority of snow and negative road surface temperature events. The model was then extended to all of France with an 8-km grid resolution, using forcing data from a real-time meteorological analysis system. Many events with snow on the roads were simulated for the 2004/05 winter. Results for road surface temperature were checked against road station data from several highways, and results for the presence of snow on the road were checked against measurements from the Météo-France weather station network.

scholarly journals THE BITUMEN BATCHING SYSTEM'S MODERNIZATION AND ITS EFFECTIVE ANALYSIS AT THE ASPHALT MIXING PLANT

Transport ◽  
2010 ◽  
Vol 25 (3) ◽  
pp. 325-335 ◽  
Author(s):  
Justas Bražiūnas ◽  
Henrikas Sivilevičius
Keyword(s):  
Asphalt Concrete ◽  
Additive Model ◽  
Technological Parameters ◽  
Destructive Effect ◽  
The Road ◽  
Weighted Matrix ◽  
Bitumen Content ◽  
Before And After ◽  
On The Road ◽  
And Performance

Some particular aspects such as the improvement methods of technological parameters for hot bitu‐ men storage in a pipeline transport system, transportation and dosed supply to batch asphalt mixing plant (AMP) are evaluated in this paper. Bitumen in asphalt concrete binds together the material of mineral particles into a strong conglomerate of a complicated structure, capable of withstanding the destructive effect of vehicles and the factors on the road pavements. The optimal amount of bitumen determined by calculation and laboratory testing should be maintained in mix batches of hot‐mix asphalt (HMA) obtained from AMP mixer. In the periodic type of the asphalt concrete blender mass of the weighted matrix in the all merging batcher's tanks should correspond in percents equally in the HMA to the designed amount of the job‐mix formula (JMF). The bitumen batcher does not always weigh bitumen portions precisely. Their mass deviations from the amount determined by JMF and its variation impair HMA composition and performance. In addition,, an additive model for calculating the effect of factors causing the variance of bitumen content in the produced HMA mixture is presented in this current paper as well. The data on statistical evaluation of bitumen batcher's modernization performed at certain Lithuanian Enterprise are discussed. The differences in structures of reconstructed and not reconstructed bitumen batching systems (BBS) are analysed and methods of determining modernization effectiveness are presented. The effectiveness of BBS is analysed too, defining the deviations of bitumen content in subsamples, taken and extracted everyday for two seasons (before and after the batcher's modernization) of HMA mixture production from the value of JMF and comparing them to the values of tolerances. The analysis of column charts and histograms shows that the made modernization helped to increase the precision of supplying the required amount of bitumen to HMA mixture insignificantly. However, the control of BBS has been considerably increased.

Effects of Speed Bumps and Humps on Motorcycle Speed Profiles

2014 ◽  
Vol 931-932 ◽  
pp. 536-540 ◽  
Author(s):  
Wichuda Satiennam ◽  
Thaned Satiennam ◽  
Pornsiri Urapa ◽  
Tussawan Phacharoen
Keyword(s):  
Developing Countries ◽  
Developed Countries ◽  
Vehicle Speed ◽  
Passenger Car ◽  
The Road ◽  
Acceleration Rate ◽  
Major Mode ◽  
Before And After ◽  
On The Road ◽  
Speed Humps

In developed countries, the use of speed humps and bumps have evolved from extensive research and testing which been properly designed and standardized. On the contrary in developing countries, no systematic and scientific studies have been carried out on that environment, especially the study on the effects that the motorcyclists response to the humps and bumps. This study therefore reveals the riders behavior when negotiating their speed to the devices. A case study was conducted in the provincial cities of Thailand where the motorcycle was a major mode of transportation. Six locations with speed humps and bumps were selected. Vehicles passing times were simultaneously recorded at 12 points along each traffic calmed link. From these data, a speed profile for each individual vehicle and for a link could be derived. It is found that speed humps and bumps have critically different impacts on motorcycle rider and passenger car driver. The smaller size speed bumps could effectively control the rider speed but have diverse impacts on the driver. These speed differences could post more safety deficiency to the site. The effect of the device on riders behavior, however, is restricted to a short spatial range (about 20-30 m before and after the device). For the speed humps, the motorcycle speeds are quite varied depending mainly on the road terrain. It is found that the motorcyclists have significant lower acceleration rate on the upgrade terrain when compared to the passenger car. Therefore, it is important to take all these rider characteristics into considerations when design the road humps to control vehicle speed in the developing countries.

Pituitary-gonadal response to gonadotropin-releasing hormone stimulation is enhanced in men after strenuous physical exercise

1993 ◽  
Vol 129 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Tommi J Vasankari ◽  
Urho M Kujala ◽  
Simo Taimela ◽  
Ilpo T Huhtaniemi
Keyword(s):  
Growth Hormone ◽  
Physical Exercise ◽  
Gonadotropin Releasing Hormone ◽  
Adult Males ◽  
Response Curves ◽  
Releasing Hormone ◽  
The Road ◽  
Strenuous Physical Exercise ◽  
Before And After ◽  
On The Road

The effects of strenuous physical exercise were studied on the pituitary-testicular response to gonadotropin-releasing hormone (GnRH) stimulation and on growth hormone (GH) and cortisol secretion. Eight healthy adult males were injected twice intravenously with 0.1 mg of GnRH at intervals of 21 days. At the time of the first injection (exercise trial) the subjects had been bicycling for 4 h on the road, and at the time of the second injection (rest trial) they had been resting in a sitting position for 4 h. Blood samples were taken before and after the 4-h period and 30, 60 and 120 min after the GnRH injection. Both testosterone and luteinizing hormone (LH) decreased during the exercise by 18% (p=0.037) and 29% (p=0.0028), respectively, but increased after the GnRH injection by 1.4- and 12.9-fold (p=0.0001 for both). The areas under the testosterone and LH response curves after GnRH were significantly larger in the exercise trial than in the rest trial, threefold (p = 0.013) and 1.3-fold (p=0.0007), respectively. Growth hormone and cortisol increased during the exercise trial. In the rest trial, the GnRH injection increased serum GH concentrations (p = 0.02 7). In conclusion, the diminished hypothalamic GnRH secretion seems to be the major cause of the post-exercise decrease in LH and testosterone, but altered sensitivity of the pituitary to GnRH also may be involved. Apparently, the build-up of pituitary LH stores during exercise explains the enhanced LH and testosterone response to GnRH challenge after exercise in comparison to control GnRH challenge.

scholarly journals Evaluation of the Safe Routes to Transit Program in California

2015 ◽  
Vol 2534 (1) ◽  
pp. 92-100
Author(s):  
David Weinzimmer ◽  
Rebecca L. Sanders ◽  
Heidi Dittrich ◽  
Jill F. Cooper
Keyword(s):  
Air Quality ◽  
San Francisco ◽  
San Francisco Bay ◽  
Economic Benefits ◽  
The Road ◽  
Before And After ◽  
Perceptions Of Safety ◽  
Food And Drink ◽  
On The Road ◽  
And Control

This paper elaborates on findings from an evaluation of the San Francisco Bay Area's Safe Routes to Transit (SR2T) program in California. This program funded enhancements to increase walking and cycling to regional transit stations. To understand how the program influenced travel choices, behavior, and perceptions of safety and local air quality, the study surveyed transit users and observed driver, pedestrian, and bicyclist behavior in the periods before and after the enhancements were made at multiple transit stations. Data from the treatment and control stations suggested that the streetscape and roadway improvements made through the SR2T program positively influenced the propensity to walk, bicycle, and take the bus to transit stations, as reported through surveys. In particular, the results showed that walking and bicycling increased by 3% at treatment sites compared with control sites. Bicycling also increased at control sites; this factor indicated a general societal shift. Furthermore, driving decreased 2.5% at treatment sites. Perceived air quality, in general, improved in the posttime period. When asked about perceived traffic risk, bicyclists more than pedestrians reported feeling safer on the road, with 10% of the bicyclists, on average, feeling safer after the improvements. There were also economic benefits from this project—pedestrians and bicyclists were overrepresented in those who stopped en route to transit for food and drink. The evidence suggested that the SR2T program positively affected the decision to walk and bicycle to access transit. The program is recommended for expansion to additional sites.

Road Surface Characteristics and Skidding Resistance

1967 ◽  
Vol 40 (3) ◽  
pp. 684-693 ◽  
Author(s):  
Barbara E. Sabey
Keyword(s):  
Large Scale ◽  
High Pressures ◽  
Water Film ◽  
Surface Characteristics ◽  
Road Surface ◽  
Dominant Factor ◽  
Fine Scale ◽  
The Road ◽  
Drainage Channels ◽  
On The Road

Abstract When roads are wet their skidding resistance is reduced by the lubricating action of the film of water on the road. Under some circumstances this reduction may be substantial and the extent of it is largely dependent on the characteristics of the road surface. The first requirement for a good skidding resistance on wet roads is to facilitate break through of the water film in order to establish areas of dry contact between the road and the tire. Drainage channels, provided by the large scale texture of the road or by a pattern on the tire, assist in getting rid of the main bulk of water and are of increasing importance the higher the speed. The penetration of the remaining water film can be achieved only if there are sufficient fine scale sharp edges in the road on which high pressures (about 1000 lb/in2) are built up. The existence of such fine scale sharpness gives the surfaces a harsh feel. When vehicles are travelling at speeds of about 30 mph the fine scale texture of the road is the dominant factor determining skidding resistance. However, as they travel faster, it becomes increasingly difficult to penetrate the water film in the time available, however harsh the surface. At high speeds the requirements for a good skidding resistance are therefore different. The resistance to skidding arises to a larger extent from energy losses in the rubber of the tire as the surface of the tread is deformed by projections in the road surface and, although the physical properties of the tread rubber are important in this respect, it is essential to have sufficiently large and angular projections in the road surface to deform the tread, even though a water film may still be present on the surface. At higher speeds the coarseness of texture becomes as important as its harshness.

Site Soil Investigations for Road Rehabilitation

2017 ◽  
Vol 21 ◽  
pp. 372-379
Author(s):  
Vasile Boboc ◽  
Ancuţa Rotaru ◽  
Andrei Boboc ◽  
Gupinath Bhandari
Keyword(s):  
Road Traffic ◽  
Surface Condition ◽  
Physical And Mechanical Properties ◽  
Soil Parameters ◽  
The Road ◽  
The North ◽  
Geotechnical Characteristics ◽  
On The Road ◽  
National Road ◽  
Short Time

The soil investigation performed on site identifies the physical and mechanical properties of the soil under the present road structure as well as the nature and thickness of the road structure to rehabilitate it when the road surface condition becomes poor or defective due to ageing, weathering and road traffic action. The rehabilitation processes re-assess the soil parameters to restore the pavement surface to the required level of service based on the recommendations of the field stratification as well as of the geotechnical characteristics of the studied emplacement. The paper presents the soil investigations on site along DN29 Suceava-Botoşani-Săveni-Manoleasa, Km 18+075 section of national road in Romania to get the information on subsurface conditions. The national road DN29 Suceava-Botoşani-Săveni-Manoleasa is covering the north-eastern part of Romania, in Moldavia region. Since its asphalt works in the '70s and '80s, nothing but partial sections of asphalt works has been carried out having never undergone major repairs. Due to external factors such as rain, snow, and traffic, the minor works that had been made make it usable for a short time, the results of soil investigation clearly attesting the rehabilitation priority. Some geotechnical characteristics of the national road DN29 Suceava-Botoşani-Săveni-Manoleasa, Km 18+075 section in Romania appear in comparison with those identified on site on the road DN29A Suceava-Dorohoi-Darabani, Km 50+075, in Romania, under a road structure that needed rehabilitation works as well.

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