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Copyright of VAD: Veredes, Arquitectura y Divulgación is the property of Alberto Alonso Oro and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Smart Rail Transit is the property of Smart Rail Transit Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The influence of silica fillers with different specific surface areas on the technological and operational properties of protective elastomer compositions has been studied. It has been established that compositions with a more highly dispersed silicic acid filler have a 10% higher Mooney viscosity and a higher dispersing ability in the elastomeric matrix (the complex dynamic modulus characterizing the Payne effect is reduced to 10%) compared to a sample containing a filler with a lower dispersion of equivalent dosage. It was determined that, with equal filling, tread rubber with a filler with greater dispersion is characterized by increased nominal stress at 300% elongation (by 21%), wear resistance, and dry road adherence (mechanical loss tangent values measured at –60 and +20°C, an increase by 21 and 11%, respectively). It was revealed that reducing the dosage of highly dispersed filler leads to the production of vulcanizates with greater elasticity and lower rolling losses while maintaining other car handling parameters. [ABSTRACT FROM AUTHOR]

Slip and fall related injuries are common in workplaces and sufficient shoe-floor friction is required to prevent such incidents. Besides the presence of slippery contaminants, shoe wearing over time is one of the key factors which may lead to significant reduction in shoe-floor friction. While footwear-based slip testing has been conducted widely across floorings and contaminants, limited studies have focused on the effect of worn shoes on slipping. In this work, twelve formal shoes from common brands were tested through modelling of their outsoles in normal and different degrees of progressively worn conditions. Mechanical slip testing was conducted to quantify the available coefficient of friction (ACOF) of the outsole models across dry and two common contaminant conditions (i.e., floor or surface cleaner, and canola oil), and on three commonly available floorings. The effect of flooring, contaminant, and worn area, on the ACOF were characterized extensively. Progressively worn outsoles were found to lead to reduction in ACOF in the range of 28-97%. Outsoles having tread channels oriented at different angles with respect to the direction of footwear motion, were found to generate higher ACOF, than ones with horizontal tread patterns. Outsoles which had larger treads but with lesser intervals (i.e., large tread surface area) showed lower ACOF values. These outsoles experienced less reduction in the ACOF in the following cycles of wear. For safety against slips, outcomes from this work are expected to provide essential information for buying or replacing the formal shoes in its new or worn condition.

This article describes the preparation of chloroacetated natural rubber (CNR) through the epoxidation of natural rubber (NR) latex with performic acid, followed by the reaction with chloroacetic acid. Ultrasound waves were utilized to accelerate the epoxidation reaction. The CNR samples obtained at various epoxidation durations were analyzed by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography, and differential scanning calorimetry techniques. Results showed that the chloroacetate content in CNR increased with increasing epoxidation time, i.e., the chloroacetate contents were 17.4, 18.5, and 19.7% at epoxidation times of 30, 45, and 60 min, respectively. The prepared CNR samples were then employed to replace NR in silica-filled tire tread compounds based on a 70/30 solution styrene butadiene rubber (SSBR)/NR blend. It was found that, compared with NR, CNR provided significantly higher rubber-silica interaction, leading to improved mechanical and dynamic properties. Such replacement not only reduced heat build-up and rolling resistance, but also increased the wet grip index, which is highly beneficial for the production of high-performance passenger car tires. It could be observed that the improvements in rubber properties and tread performance were more obvious when the chloroacetate content of CNR was increased, probably due to the enhanced rubber-filler interaction, as demonstrated by the increased bound rubber content.

The increasing demand on passenger car tires requires a continuous effort of tire manufacturers to improve their performance and safety. Achieving a balance between the three properties that form the “Magic Triangle of Tires” is one of the biggest challenges in this field. This work aims to improve this balance between wet grip, rolling and wear resistance by the use of performance hydrocarbon resins as an alternative to treated distillate aromatic extracted (TDAE) oil in tire tread compounds. In this framework, the effect on the in-rubber properties of five different hydrocarbon resins with different chemical nature, was studied in a styrene butadiene rubber (SBR)/polybutadiene rubber (BR) blend. The effect of the resins was analyzed by the use of different experimental techniques. All the compounds containing resin in their formulation, independently of their amount and chemical nature, showed an increase in the wet grip indicator and abrasion resistance indicator. However, it also was observed a deterioration in the rolling resistance indicator.

Slip and fall related injuries are common in workplaces and sufficient shoe-floor friction is required to prevent such incidents. Besides the presence of slippery contaminants, shoe wearing over time is one of the key factors which may lead to significant reduction in shoe-floor friction. While footwear-based slip testing has been conducted widely across floorings and contaminants, limited studies have focused on the effect of worn shoes on slipping. In this work, twelve formal shoes from common brands were tested through modelling of their outsoles in normal and different degrees of progressively worn conditions. Mechanical slip testing was conducted to quantify the available coefficient of friction (ACOF) of the outsole models across dry and two common contaminant conditions (i.e., floor or surface cleaner, and canola oil), and on three commonly available floorings. The effect of flooring, contaminant, and worn area, on the ACOF were characterized extensively. Progressively worn outsoles were found to lead to reduction in ACOF in the range of 28-97%. Outsoles having tread channels oriented at different angles with respect to the direction of footwear motion, were found to generate higher ACOF, than ones with horizontal tread patterns. Outsoles which had larger treads but with lesser intervals (i.e., large tread surface area) showed lower ACOF values. These outsoles experienced less reduction in the ACOF in the following cycles of wear. For safety against slips, outcomes from this work are expected to provide essential information for buying or replacing the formal shoes in its new or worn condition. [ABSTRACT FROM AUTHOR]

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The severe threat to aquatic environment from zinc oxide (ZnO) in tread debris has become a serious issue for tire manufacturers. Various attempts including the utilization of composite ZnO have therefore been made to reduce ZnO content in tread compounds. In this study, a new composite ZnO was prepared by depositing ZnO nanoparticles on microcrystalline cellulose (MCC) through hydrothermal reactions, called M‐ZnO. After characterization by various techniques, cure activation efficiency of M‐ZnO in truck tire tread compound was investigated and compared with that of active ZnO (A‐ZnO). The results showed that M‐ZnO contained approximately 66.7% w/w of ZnO and had comparable specific surface area to A‐ZnO. Regardless of the ZnO type, crosslink density increased with increasing ZnO content up to 3 phr leading to the improved mechanical properties of the rubber vulcanizates, that is, hardness, modulus, and abrasion resistance. Tensile and tear strengths, however, were found maximum at 2 phr of both A‐ZnO and M‐ZnO. Although wet grip index was independent of ZnO content, rolling resistance tended to reduce with increasing ZnO content. The results clearly show the great potential of utilizing M‐ZnO to replace conventional A‐ZnO in tread compounds when more stringent environmental regulations are imposed. [ABSTRACT FROM AUTHOR]

The railway wheel is the key component of high-speed railway train. To assure the safety in service, higher requirements are put forward in this study for the composition, microstructure uniformity, and comprehensive properties of wheel materials. In this paper, the high throughput quantitative distribution characterization methods of composition, microstructure, inclusions and Vickers hardness of high-speed railway wheel materials based on the spark source original position analysis technique, high throughput scanning electron microscope (SEM) combined with image batch processing technology, and automatic two-dimensional quantitative distribution analysis technique of inclusions and micro hardness have been studied. The distribution trend of the content of nine elements, size and quantity of sulfides and oxides, ferrite area fraction, and Vickers hardness from the wheel tread surface to the radial depth of about 50 mm below the surface has been discussed. The influence of inclusions distribution on the element segregation and the effect of rim-chilling process with different water spraying angle on the distribution of microstructure and micro hardness have been investigated. It was found that unsynchronized cooling on both sides of the rim altered the phase behavior of ferrite and pearlite and obvious inhomogeneity distribution of ferrite appeared, which led to the asymmetrical Vickers hardness in areas near or away from the flange. Based on the quantitative characterization of area fraction and micro hardness on the same location of wheel rim, a statistical mapping relationship between ferrite area fraction and Vickers hardness was established. [ABSTRACT FROM AUTHOR]

Due to the complexity of friction phenomena, empirical analysis is the best way to predict the friction coefficient. To accomplish this, laboratory test rigs are needed. Although a rotary dynamic friction test bed was available to the authors, it had its limitations, such as low speed, inducement of lateral force, and the limitation of testing samples with different shapes. This paper will explain the process of designing and manufacturing a novel test setup for measuring friction and wear of the tire. The newly designed test rig can apply dynamic loading during the tests, and it can automatically measure the wear rate and temperature between cycles. In addition, it can be used for measuring the wear rate of rubber samples sliding on different types of surfaces. Therefore, experiments can be run under more controlled conditions. The designed linear friction tester can slide flat and round rubber samples approximately three meters across a large flat surface. The frictional force of rubber samples can be measured for various normal loads, velocities, and surface conditions. The new setup can automatically control the applied normal load on the sample using proportional–integral–derivative controller control. The important difference between this novel design and the existing testers used by other researchers is implementing the ball screw technology and the servo motor with high accuracy encoder to achieve highly accurate test results. In this design, the new mechanism for the ball screw is designed to increase the speed limit and eliminating vibrations while keeping the precision. In addition, in this design, the sample's mass can be measured automatically after each test cycle, thus providing a measure of the rate of wear of the rubber. In this study, the data collected by the linear friction tester is validated by comparing the data to the data collected by the dynamic friction tester (a validated rotary friction tester that exists in CenTiRe Lab). The data collected by the new setup was later used to benchmark the Persson analytical friction model. [ABSTRACT FROM AUTHOR]

In the tire industry, the incorporation of natural origin oils in the development of elastomeric formulations has been one of the alternatives to reduce the use of petroleum derivatives, with a high content of toxic compounds. In this work, soybean vegetable oil was investigated as a lubricant and co-activator in sulfur-vulcanized natural rubber compounds. The soybean oil was used in its natural state and chemically modified by the epoxy ring's introduction in its structure. In an internal mixer a standard formulation of natural rubber, five formulations replacing a conventional aromatic oil and stearic acid by vegetable oil, and a formulation without an activation system were prepared. The natural and epoxidized soybean oil was characterized chemically, and the elastomeric compositions were evaluated by mechanical and rheological analysis. The mechanical properties showed satisfactory results when vegetable soybean oil was used as a lubricant and could be a substitute for conventional aromatic oils, thus guaranteeing reduction of aromatic polycyclic content in the formulations. The crosslink degree and the rheological characteristics of the samples prepared with vegetable soybean oil were similar to the natural rubber standard sample. The formulations without the zinc oxide and stearic acid evidenced the need for activators in the vulcanization reaction, as they presented properties below standard. We verified that the epoxidized soybean oil, even when promoting better dispersion of the fillers, interfered in the crosslink formation, and consequently there was a decrease in the mechanical properties of these formulations. Finally, we indicated vegetable soybean oil as a substitute for aromatic oil and stearic acid, in the elastomeric compositions used to manufacture treads. [ABSTRACT FROM AUTHOR]

Footwear outsole design is an important factor for shoe-floor friction and for preventing slipping. Shoes with small, uniformly-separated tread blocks (often included on slip-resistant shoes) have decreased slip risk due to their increased friction and better under-shoe fluid drainage. However, these traction performance metrics (friction and fluid drainage) diminish with wear. This study quantifies shoe traction performance in response to natural wear and compares the relationship between common wear metrics: time, distance walked, and worn region size (WRS). Participants wore two pairs of shoes in the workplace for up to 11 months and the distance walked was tracked with a pedometer. After each month of wear, traction performance and WRS of each shoe were measured. Traction performance was quantified by the under-shoe available coefficient of friction and fluid force during a simulated slip test. Increased wear (months worn, distance walked, and WRS) was associated with decreased traction performance. A WRS of 800 mm2 was associated with reductions in friction of 16–38% and increases in fluid force by 286–528%. Three and six months of wear were associated with WRS values of 251 mm2 and 462 mm2 and distances of 203 km and 519 km, respectively. A walking distance of 500 km was associated with a WRS of 406 mm2. This study showed that all of these wear metrics are good indicators of shoe traction performance loss. Thus, the most practical metric in a particular application can be selected. We argue that WRS may be the best indicator due to variations in wear rate from the user and environment. Therefore, tracking footwear usage and monitoring outsole wear can aid in shoe replacement recommendations to reduce slips and falls. [ABSTRACT FROM AUTHOR]

Slabless reinforced concrete (RC) staircases attract architects with their aesthetically pleasing appearance and are therefore especially preferred for the interior design of prestigious buildings. The design and detailing of such staircases are based on analytical approaches and engineering judgment. However, these analytical methods are not supported by extensive experimental research. Besides, engineers have to deal with lots of uncertainties due to a lack of experimental data. Therefore, experimental research was conducted to investigate the flexural behavior of slabless staircases. A total of 12 two-thirds-scaled specimens with four different reinforcement arrangements and three different tread/riser thicknesses were prepared for testing under six-point monotonic loading. The results show that tread thickness, rather than riser thickness, significantly affects the behavior of slabless staircases. In addition, it has been found that the planar reinforcement can greatly improve the behavior and prevent possible bonding problems. The results are also consistent with the adopted analytical approaches. [ABSTRACT FROM AUTHOR]

The railway wheel is the key component of high-speed railway train. To assure the safety in service, higher requirements are put forward in this study for the composition, microstructure uniformity, and comprehensive properties of wheel materials. In this paper, the high throughput quantitative distribution characterization methods of composition, microstructure, inclusions and Vickers hardness of high-speed railway wheel materials based on the spark source original position analysis technique, high throughput scanning electron microscope (SEM) combined with image batch processing technology, and automatic two-dimensional quantitative distribution analysis technique of inclusions and micro hardness have been studied. The distribution trend of the content of nine elements, size and quantity of sulfides and oxides, ferrite area fraction, and Vickers hardness from the wheel tread surface to the radial depth of about 50 mm below the surface has been discussed. The influence of inclusions distribution on the element segregation and the effect of rim-chilling process with different water spraying angle on the distribution of microstructure and micro hardness have been investigated. It was found that unsynchronized cooling on both sides of the rim altered the phase behavior of ferrite and pearlite and obvious inhomogeneity distribution of ferrite appeared, which led to the asymmetrical Vickers hardness in areas near or away from the flange. Based on the quantitative characterization of area fraction and micro hardness on the same location of wheel rim, a statistical mapping relationship between ferrite area fraction and Vickers hardness was established.

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The solid tire performance can be characterized by the contact patch. The footprint is the particular method to achieve the contact patch between a tire and pavement. The flat surface is often equipped to support a pressure measurement film which is pressed by the tire tread. This derivative patch illustrates characteristic seems the probable result to predict tire performance. Practically, the contact patch happens by the rolling tire. To understand the patch characteristic, the contact patch between the rolling tire and pavement was studied. The 3D finite element model of solid tire which pressed on three different surfaces was developed. The experimental footprint on the flat surface was carried out to validate the finite element model. The contact patch of solid tire tread on the drum surface was investigated to discuss the effect of supporting floor under various testing method. The stress distribution in the solid tire model is the exceptional criteria to clarify the contact patch on the road. The developed models will be used to design the tire tread and pavement in the future work. [ABSTRACT FROM AUTHOR]

[Display omitted] This article describes the preparation of chloroacetated natural rubber (CNR) through the epoxidation of natural rubber (NR) latex with performic acid, followed by the reaction with chloroacetic acid. Ultrasound waves were utilized to accelerate the epoxidation reaction. The CNR samples obtained at various epoxidation durations were analyzed by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography, and differential scanning calorimetry techniques. Results showed that the chloroacetate content in CNR increased with increasing epoxidation time, i.e., the chloroacetate contents were 17.4, 18.5, and 19.7% at epoxidation times of 30, 45, and 60 min, respectively. The prepared CNR samples were then employed to replace NR in silica-filled tire tread compounds based on a 70/30 solution styrene butadiene rubber (SSBR)/NR blend. It was found that, compared with NR, CNR provided significantly higher rubber-silica interaction, leading to improved mechanical and dynamic properties. Such replacement not only reduced heat build-up and rolling resistance, but also increased the wet grip index, which is highly beneficial for the production of high-performance passenger car tires. It could be observed that the improvements in rubber properties and tread performance were more obvious when the chloroacetate content of CNR was increased, probably due to the enhanced rubber-filler interaction, as demonstrated by the increased bound rubber content. [ABSTRACT FROM AUTHOR]

Motor vehicle end-users approaches to tyre safety issues in automobiles translate to a number of tyre failure risk factors. This study basically assessed tread wear pattern of tyres in passenger cars used on Nigeria roads. The result obtained showed that 75.4% of the assessed tyres showed uneven wear pattern resulting from incorrect tyre-road contact effects. This observed high proportion of uneven tyre tread wear pattern implies high rate of inconsequential regard for tyre safety.

The increasing demand on passenger car tires requires a continuous effort of tire manufacturers to improve their performance and safety. Achieving a balance between the three properties that form the "Magic Triangle of Tires" is one of the biggest challenges in this field. This work aims to improve this balance between wet grip, rolling and wear resistance by the use of performance hydrocarbon resins as an alternative to treated distillate aromatic extracted (TDAE) oil in tire tread compounds. In this framework, the effect on the in-rubber properties of five different hydrocarbon resins with different chemical nature, was studied in a styrene butadiene rubber (SBR)/polybutadiene rubber (BR) blend. The effect of the resins was analyzed by the use of different experimental techniques. All the compounds containing resin in their formulation, independently of their amount and chemical nature, showed an increase in the wet grip indicator and abrasion resistance indicator. However, it also was observed a deterioration in the rolling resistance indicator. • Comparison of different hydrocarbon resins as an alternative to TDAE oil. • Effect of hydrocarbon resins in the Magic Triangle of Tires. • Effect of the chemical nature of the resins in the in-rubber properties. • Strong effect of the softening point of the resins in the in-rubber properties. [ABSTRACT FROM AUTHOR]

Tyres represent the only element which connects a vehicle with a roadway and they are one of the most important parts of the vehicle. Investigated samples from chosen agricultural tyres were placed into a degradation medium. Degradation media were chosen on the basis of their supposed application; the second criterion of the choice was operating liquids used in machines. A primary aim was defining a change of hardness of these samples; the second-rate aim was observing changes of a tyre weight. The aim of the research is an evaluation of the hardness change in surface layers of a tread depending on specific degradation environments to which the tyre is potentially exposed. The highest influence on the hardness was proved in the case of diesel oil and engine oil. Any essential influence of NPK fertilizer solution was not proved. The effect of water and a solution of NaCl on the hardness change was minimal.

The aim of the forensic investigation of traffic accidents is to help establish the nature and/or the circumstances of the event. This might be done with the purpose of determining the legal responsibilities of each person involved or to provide families, with a reconstruction of the events, to help understand why their relatives were injured or killed. A methodology for the comparison of chemical profiles of tire traces and tire tread samples obtained by pyrolysis-gas chromatography/mass spectrometry has been developed. Chemical profiles are represented by relative abundances of 86 compounds. The variability of the tread within and between 12 tires was assessed. Considering the level of the source as "brand and model" the intra-variability was found to be smaller than the inter-variability, leading to the complete discrimination of the 12 tires of the sample set. Braking tests were carried out on a racetrack in order to produce tire traces which origin was known. The results obtained with a supervised classification method showed that more than 94% of the replicates of the traces were correctly assigned to the class membership (i.e., brand and model) of the tire at their origin. These results support that the chemical profile of one trace does not differ from the chemical profile of the tire at its origin but differs generally from the other chemical profiles of the sample set.

Abstract: A method for calculating the frictional moment in cageless rolling bearings has been developed. Test results of cageless bearings have been shown in the study and comparison of experimental data of frictional moments with theoretically calculated frictional moments has also been shown. A conclusion has been drawn about the correctness of the method based on the data collected from the experiments. [ABSTRACT FROM AUTHOR]