Lubricated Friction of Rubber. VII. Notes on a Standard Tire and Procedure for Skid Testing

1968 ◽  
Vol 41 (4) ◽  
pp. 890-894
Author(s):  
E. M. Bevilacqua ◽  
E. P. Percarpio
Keyword(s):  
A Priori ◽  
Resistance Testing ◽  
A Priori Knowledge ◽  
Skid Resistance ◽  
Rational Basis ◽  
Specific Detail ◽  
The Road ◽  
The Past ◽  
Road Surfaces ◽  
Set Up

Abstract In an effort to achieve uniformity in testing and reporting skid resistance as a necessary preliminary to attempts to make improvements in roads on a rational basis, cooperative efforts have been underway over the past several years to standardize apparatus and equipment. One part of this effort has been the designation of a standard tire (ASTM E249-64T) for skid resistance testing. At the time this standard was set up important factors in skid resistance were not fully known and a composition was chosen on the basis that it was representative of actual tread stocks which have been used and had skid resistance shown by experience to be satisfactory. We have recently described evidence that the skid resistance of tires on real roads can be described absolutely in terms of properties of the tread stock which can be measured readily in the laboratory. In the course of this work we have further found evidence that the proposed standard tire is not as sensitive to variation in properties of the road as others which might be used. We have also shown that important properties of the road surface can be measured without a priori knowledge of the character of the road by the use of more than one rubber composition at the same location. Finally, we have observed that speed sensitivity of friction on road surfaces can be determined by low speed measurements. This report is therefore written to suggest that consideration be given to revision of procedures currently in view to take advantage of advances in our present state of knowledge. Since the recommendations constitute a substantial departure, they are not set forth here in specific detail, but their basis presented for consideration.

Designing skid resistance testing programs using videotaped road inventory data

1998 ◽  
Vol 25 (5) ◽  
pp. 950-955
Author(s):  
J David Innes ◽  
F R Wilson ◽  
Denis R Goguen
Keyword(s):  
Significant Proportion ◽  
Measured Data ◽  
Highway Safety ◽  
Resistance Testing ◽  
Skid Resistance ◽  
Inventory Data ◽  
The Road ◽  
Road Surfaces ◽  
Wide Testing ◽  
Level Of Agreement

It is generally accepted that road skid resistance should be carefully monitored. However, system-wide testing programs are generally expensive in terms of both manpower and equipment costs. Programs that test only road sections where the road surface is either inadequate or of marginal quality would be more economical than one in which all roads are tested, particularly where a significant proportion of the road surfaces in the system are clearly adequate. This paper examines the potential for using videotaped road inventory data to identify road sections that are either slippery or of marginal quality in terms of skid resistance. It reports on research conducted which examined the ability of individuals to identify inadequate road sections and discriminate these road sections from those with good surfaces by using VHS and super-VHS road inventory videotaped images. Videotaped records of road sections were evaluated by a panel. Their responses were then compared with skid resistance test data. A statistical analysis showed no satisfactory level of agreement between measured data and video evaluations for the VHS records. A second series of tests was conducted using super-VHS technology. The results of the second series of tests showed much better agreement. The research provided promising results and it would appear that videotaped road inventory data could be used as part of a protocol that could be developed to identify the sections that should be field tested as part of a system-wide skid resistance monitoring program.Key words: highway safety, skid resistance, program design, pavement characteristics, video evaluation.

scholarly journals Vibration Data Processing for Bedload Monitoring in Underwater Environments

2020 ◽  
Vol 12 (17) ◽  
pp. 2797
Author(s):  
Gabriel Vasile
Keyword(s):  
Data Processing ◽  
Total Energy ◽  
Steel Plate ◽  
A Priori ◽  
A Priori Knowledge ◽  
Vibration Spectra ◽  
Vibration Data ◽  
Accurate Localization ◽  
Set Up ◽  
Processing Framework

This paper proposes a novel data processing framework dedicated to bedload monitoring in underwater environments. After calibration, by integration the of total energy in the nominal bandwidth, the proposed experimental set-up is able to accurately measure the mass of individual sediments hitting the steel plate. This requires a priori knowledge of the vibration transients in order to match a predefined dictionary. Based on unsupervised hierarchical agglomeration of complex vibration spectra, the proposed algorithms allow accurate localization of the transients corresponding to the shocks created by sediment impacts on a steel plate.

Skidding Characteristics of Pavement Surfaces Incorporating Steel Slag Aggregates

1996 ◽  
Vol 1545 (1) ◽  
pp. 35-40 ◽  
Author(s):  
A. F. Stock ◽  
Colin M. Ibberson ◽  
I. F. Taylor
Keyword(s):  
Steel Industry ◽  
Steel Slag ◽  
Road Construction ◽  
Specimen Preparation ◽  
Skid Resistance ◽  
Performance Measurements ◽  
Performance Expectations ◽  
The Past ◽  
Set Up

Steel slag, a by-product of the steel industry, has been used in road construction in South Yorkshire and its environs for the past 60 years. Local highway engineers have anecdotal evidence of good long-term antiskid performance from road surfacings that incorporate steel slag aggregate, and these materials have remained popular with users. In view of the move toward performance measurements for paving materials, a systematic study of the performance of paving materials incorporating slag has been set up as a combined industry-university project with the assistance of the Teaching Company Directorate. The evaluation of the skid resistance characteristics of steel slag aggregates and the skidding characteristics of pavement surfaces incorporating steel slag aggregate are reported. The research program developed a modified specimen preparation procedure that significantly reduced the scatter in polished stone value (PSV) results. The field data showed that all steel slag surfaces provided good long-term skid resistance and that the 14-mm chippings exceed the performance expectations of rock chippings with similar PSVs.

Lubricated Friction of Rubber. I. Introduction

1968 ◽  
Vol 41 (4) ◽  
pp. 832-842 ◽  
Author(s):  
E. M. Bevilacqua ◽  
E. P. Percarpio
Keyword(s):  
Skid Resistance ◽  
Relative Importance ◽  
The Road ◽  
Quantitative Estimates ◽  
Road Surfaces ◽  
Quantitative Basis ◽  
Improved Technique ◽  
Tread Rubber ◽  
Wet Skid Resistance

Abstract This review introduces a series of reports on a quantitative study of friction of rubber on wet surfaces. It was derived from concern over safety aspects of skidding on wet roads; this first paper deals with the relation between safety and traction. Subsequent papers deal with: A quantitative approach to characterization of road surfaces, identification of the surface features of importance, and estimation of their relative contributions to lubricated friction. Quantitative estimates of effects of properties of rubber materials on lubricated friction and an analysis of their relative importance in interaction with the significant features of the road surface. A quantitative basis for evaluation of wet skid resistance of roads, the choice of the rubber to be used in this evaluation, and methods of testing. An improved technique to measure the property of tread rubber important for wet skid resistance of tires. Identification and interpretation of the nature of friction on ice at low temperatures.

Genome-wide association studies

2019 ◽  
pp. 51-62
Author(s):  
Thomas W Mühleisen ◽  
Sven Cichon
Keyword(s):  
Basic Concept ◽  
Association Studies ◽  
A Priori ◽  
Genome Wide Association ◽  
Psychiatric Research ◽  
A Priori Knowledge ◽  
Genome Wide Association Studies ◽  
The Past ◽  
Genome Wide ◽  
Technological Developments

Genome-wide association studies (GWAS) have evolved over the past ten years into a very successful tool for investigating the genetic architecture of multifactorial human traits and disorders. One major advantage of GWAS is that they do not require any a priori knowledge about the biological mechanisms underlying the traits and disorders under study. This chapter describes the scientific and technological developments that made GWAS possible and the underlying basic concept of these studies. The chapter considers what has been learned from GWAS in psychiatric research so far, what are the limitations, and looks forward to the future of GWAS.

Many Hands Make Light Work: Further Studies in Group Evolution

2014 ◽  
Vol 20 (1) ◽  
pp. 163-181
Author(s):  
Nicholas Tomko ◽  
Inman Harvey ◽  
Nathaniel Virgo ◽  
Andrew Philippides
Keyword(s):  
Group Size ◽  
Fitness Landscape ◽  
A Priori ◽  
Matching Task ◽  
A Priori Knowledge ◽  
Random Group ◽  
Cooperative Tasks ◽  
Niching Methods ◽  
Set Up ◽  
Priori Knowledge

When niching or speciation is required to perform a task that has several different component parts, standard genetic algorithms (GAs) struggle. They tend to evaluate and select all individuals on the same part of the task, which leads to genetic convergence within the population. The goal of evolutionary niching methods is to enforce diversity in the population so that this genetic convergence is avoided. One drawback with some of these niching methods is that they require a priori knowledge or assumptions about the specific fitness landscape in order to work; another is that many such methods are not set up to work on cooperative tasks where fitness is only relevant at the group level. Here we address these problems by presenting the group GA, described earlier by the authors, which is a group-based evolutionary algorithm that can lead to emergent niching. After demonstrating the group GA on an immune system matching task, we extend the previous work and present two modified versions where the number of niches does not need to be specified ahead of time. In the random-group-size GA, the number of niches is varied randomly during evolution, and in the evolved-group-size GA the number of niches is optimized by evolution. This provides a framework in which we can evolve groups of individuals to collectively perform tasks with minimal a priori knowledge of how many subtasks there are or how they should be shared out.

scholarly journals Control of Chaos Using the Controller Identification Technique

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Alexandre Molter ◽  
Fabricio B. Cabral
Keyword(s):  
Nonlinear Systems ◽  
Chaotic Systems ◽  
A Priori ◽  
Dynamic Control ◽  
A Priori Knowledge ◽  
Control Of Chaos ◽  
Control Techniques ◽  
The Past ◽  
Identification Technique ◽  
Simulation Results

Modeling and simulation of chaotic system with dynamic control have been extensively presented in the past decades. Several control techniques have been proposed for the control of chaos. One technique that has not been sufficiently explored for the control of nonlinear systems is the controller identification technique. This technique is based on the evaluation of controllers even if they are not online. This technique does not use a priori knowledge of the plant parameters. In this work, we propose a class of controllers candidates to follow desired trajectories. Simulation results are presented for the control of chaotic systems.

scholarly journals Museum Work as Part of the Present – the Past is the Present, the Present is the Past

1970 ◽  
pp. 93
Author(s):  
Kirsi Liimatainen
Keyword(s):  
Road Traffic ◽  
Public Organizations ◽  
The Road ◽  
The Past ◽  
Set Up

Lilja and Olavi Sallinen set up the Mobilia Foundation in 1986 to support the operation of the commercially run Vehoniemi Car Museum and the Finnish Museum of Historical Military and Special Vehicles. In 1991, the financing of the Mobilia Foundation was transferred to public organizations when the Finnish Vehicle Administration, Kangasala municipality, the Ministry of Defence, and the Finnish Road Administration (Finnra) joined the foundation and agreed to fund a road traffic museum with a wider scope of operation. At this juncture, the Road Traffic Museum became one of the foundation’s museums, joining the two earlier museums. 

scholarly journals The Usability of Different Skid Resistance Characteristics in Road Assessment

2014 ◽  
Vol 10 (2) ◽  
pp. 80-87
Author(s):  
Matúš Kováč ◽  
Peter Kotek
Keyword(s):  
Road Network ◽  
Skid Resistance ◽  
Water Tank ◽  
Model Surface ◽  
Measuring Device ◽  
The Road ◽  
The Past ◽  
Texture Characteristics ◽  
Surface Profiles ◽  
On The Road

Abstract The article was created as a reaction on the request of the Slovak Road Administration, whether it would be possible to evaluate level of friction on the road network only by using laser equipped device Profilograph GE, instead of by using longitudinal friction coefficient measuring device Skiddometer BV11, which is slow, much more difficult on operation and it is necessary to fulfil the water tank for measurements. In order to find out the answer, there were evaluated measurements performed on road sections in Slovakia for the past few years. The main goal was to compare results obtained by both devices, and to find a relevant correlation between them. For better understanding of the problematic and for the demonstration of disadvantages of some texture characteristics, there are performed a comparisons of the different parameters evaluated on model surface profiles in the end of this work.

scholarly journals Árvore Binomial Construída via Mapas Randômicos para Análise de Ativos Financeiros

2010 ◽  
Vol 8 (1) ◽  
pp. 25
Author(s):  
Antonio Airton Carneiro De Freitas ◽  
José Roberto Securato
Keyword(s):  
A Priori ◽  
A Priori Knowledge ◽  
Financial Assets ◽  
Options Market ◽  
Binomial Tree ◽  
Random Maps ◽  
Stationary Probability Density Function ◽  
Set Up ◽  
Priori Knowledge

Random maps can be constructed from a priori knowledge of the financial assets. It is also addressed the reverse problem, i.e. from a function of an empirical stationary probability density function we set up a random map that naturally leads to an implied binomial tree, allowing the adjustment of models, including the ability to incorporate jumps. An applica- tion related to the options market is presented. It is emphasized that the quality of the model to incorporate a priori knowledge of the financial asset may be affected, for example, by the skewed vision of the analyst. (Full article available in Portuguese only)

Sign in / Sign up

Export Citation Format

Share Document