Residual Stress Measurement Techniques for Metal Joints, Metallic Coatings and Components in the Railway Industry: A Review

Manufacturing and maintenance procedures in the railway industry regularly implement welding and metal deposition operations to produce joints, coatings and repair structures. During these processes, residual stresses arise through the generation of heat affected zones and plastic deformation. This makes accurate measurements of the internal stresses a critical aspect of manufacturing, monitoring, repair and model validation in the develop new metallic coating and joining technologies. Selection of an appropriate residual stress measurement method has many important factors including component size, resolution and the magnitude and location of internal stresses, often resulting in a combination of techniques required to obtain complete assessment of the stress state. This paper offers a review of residual stress measurement techniques for railway components including rail joints and coatings through comparison of destructive and non-destructive approaches, their measurement capabilities, benefits and limitations. A comprehensive discussion of different applications is provided with a summary of facilities available to both research and industry.

Tribological Properties of Laser Cladded Alloys for Repair of Rail Components

Tram or light rail systems are heavily relied upon for passenger transit; however, low-carbon steel grades commonly used in special trackwork, such as in switches, are prone to wear, rolling contact fatigue (RCF), and deformation under cyclic wheel-rail contact. To address this, laser cladding can be used to apply a metal coating to protect the underlying substrate and rebuild the worn rail profiles. Laser cladding may also be applied to remove cracking by rebuilding the rail head. The tribological characteristics of light rail components after laser cladding with Stellite 6 and a newly developed martensitic stainless steel were investigated, using roller-on-disc wear testing. Analysis of the microstructure, mechanical properties, and wear performance was undertaken to develop a comprehensive understanding of the influence of the laser cladding type on the wear and surface fatigue performance. Both cladding alloys significantly improved the tribological performance. These findings were compared to those for a laser cladded hypereutectoid rail type (reported in our previous study). It was found that laser cladding with a suitable alloy was an effective technique for improving the tribological properties, increasing the wear resistance, and increasing the retardation of cracking on both substrates. These findings suggest laser cladding may be used to repair light rail components, and this technique can be optimized to suit different rail grades. This makes laser cladding a flexible and versatile maintenance strategy, in both coating and repair applications, to prolong the operational lifetime of critical components for the railway industry.

Application of a New Alloy and Post Processing Procedures for Laser Cladding Repairs on Hypereutectoid Rail Components

The development of a laser cladding repair strategy is critical for the continued growth of heavy-haul railway networks. Premium hypereutectoid rails have undergone laser cladding using a new martensitic stainless-steel alloy, 415SS, developed for high carbon rails after standard cladding metals were found to be incompatible. Non-destructive neutron diffraction techniques were used to measure the residual stress in different layers generated across a dissimilar metal joint during laser cladding. The internal stress distribution across the cladding, heat-affected zone (HAZ), and substrate was measured in the untempered rail, after 350 °C and 540 °C heat treatment procedures and two surface grinding operations. The martensitic 415SS depositions produce compressive stress in the cladding, regardless of tempering procedures, which may inhibit fatigue crack propagation whilst grinding operations locally relive surface stress. Balancing tensile stresses were recorded below the fusion boundary in the HAZ due to thermal gradients altering the microstructure. The combination of 540 °C tempering and 0.5 mm surface layer removal produced a desirable combination of compression in the cladding deposition with significantly reduced tensile stresses in the HAZ. A comparison with the current literature shows that this alloy achieves a unique combination of desirable hardness, low tensile stress, and compression in the cladding layer. Data obtained during strain scanning has been used to determine the location of microstructural changes at the fusion boundary and HAZ through correlation of the stress, strain, full width at half maximum (FWHM), and intensity profiles. Therefore, neutron diffraction can be used for both the accurate measurement of internal residual stress and to obtain microstructural information of a metallurgical join non-destructively.

Naked Aggression: The Meaning and Practice of Ejaculation on a Woman’s Face

Based on in-depth interviews with 16 heterosexual men, this study focuses on participants’ meaning-making surrounding a common and controversial sexual act in pornography: ejaculation on a woman’s face (EOWF). We analyze the ways that male consumers decoded EOWF and the ways that EOWF, as a sexual script, was included in the men’s accounts of their sexual desires and practices. The majority of the men decoded EOWF through the preferred (encoded) meaning as an act of male dominance and sexual aggression and that they wanted to engage in it despite their general belief that women would not be interested in it.

Assessing the surveillance capability of Canada's national health surveys

We assessed Canada's national health surveys as surveillance instruments, with emphasis on comparing the temporal structure of data sets with those generated by the US Behavioral Risk Factor Surveillance System (BRFSS). Only the Canadian Tobacco Use Monitoring Survey (CTUMS) has the BRFSS capability to generate continuous, uniform time series with monthly intervals. These time series can offer substantial extra value for retrospective analysis such as program evaluation in addition to surveillance. Expanding CTUMS is a simple option for providing an ongoing, uniform monthly survey instrument for non-tobacco variables. The Canadian Community Health Survey (CCHS) will generate monthly data, and could potentially generate useful continuous time series even though surveys at the health region and provincial levels will alternate annually. Reconfiguring the CCHS, or even implementing a provincial surveillance survey based on the BRFSS model are other viable options, but each option has associated tradeoffs or obstacles.

Shigellosis on Indian reserves in Manitoba, Canada: its relationship to crowded housing, lack of running water, and inadequate sewage disposal

OBJECTIVES

This study compares incidence and hospitalization rates for shigellosis between Indians and the rest of the population in Manitoba, Canada. It examines the relationship between shigellosis and environmental conditions on reserves.

METHODS

Rates were calculated with surveillance data and a survey of environmental infrastructure was done.

RESULTS

Indians had shigellosis incidence and hospitalization rates that were 29 and 12 times as high, respectively, as those of the rest of the population. Household crowding, lack of piped water, and inadequate sewage disposal were significantly associated with an increased incidence of shigellosis on reserves.

CONCLUSIONS

Many cases of shigellosis may be prevented by improving living conditions on Indian reserves.

Canadian health surveys, 1950 1997

This paper provides a brief history of Canadian health surveys and a review of health or health-related surveys from the first national household survey in 1950/51 to the present time. Surveys have evolved from collecting information on health care utilization, health status and some risk behaviours to a wider range of health determinants following the 1974 Lalonde report. In addition to the occasional cross-sectional surveys, there are periodic surveys, longitudinal surveys, school-based surveys and surveys based on subgroups in the population or specific topic areas. The survey review is presented in the following four tables: Table 1 summarizes national surveys including such information as the date(s) and frequency of data collection, topic areas, target population, sample size and response rate for each survey; Table 2 provides the same information for provincial surveys; both tables point to Table 3, which supplements the previous information with survey sponsors and contacts; Table 4 provides similar information for commercial surveys. This reference, which will be updated periodically, is intended to act as a source of information and support in the development of new surveys.

Incidence and prevalence of diabetes in Manitoba, 1986-1991

OBJECTIVE

To estimate the incidence and prevalence of diabetes among adults in Manitoba, Canada, from 1986 to 1991.

RESEARCH DESIGN AND METHODS

A population-based database of individuals diagnosed with diabetes (Manitoba Diabetes Database) was created using data from Manitoba Health's comprehensive insurance system. Using this database, estimates of the annual incidence and prevalence of diabetes among Manitoba adults aged > or = 25 years were made for the years 1986-1991. Age-specific and age-adjusted rates were calculated separately for men and women.

RESULTS

The prevalence of diabetes in 1991 was 66.9/1,000 among adults > or = 25 years. Between 1986 and 1991 the age-adjusted prevalence rose steadily among both men and women. In 1991, the incidence of diabetes was 5.6/1,000. After an observed decline prior to 1989, the annual incidence of diabetes appears to be relatively stable.

CONCLUSIONS

The prevalence of diabetes is increasing steadily despite relatively stable incidence rates. Population-based data are required for projecting future trends and are an important tool for planning the required health resources.

Vaccine and antiviral strategies against infections caused by human immunodeficiency virus

Human immunodeficiency virus type 1 (HIV-1) has been clearly associated with a variety of new illnesses, including profound immunodeficiency (acquired immune deficiency syndrome [AIDS]), wasting syndromes (formerly termed AIDS-related complex [ARC]) and neurologic syndromes, including neuropathy, myelopathy and encephalopathy (often termed subacute encephalitis or AIDS dementia complex). HIV-1 preferentially infects T lymphocytes by binding to a membrane receptor protein, CD4, associated with helper function. The virus can also attack macrophages and, possibly, other cells such as neuronal cells, colonic epithelial cells and B lymphocytes. Infection of macrophages or monocytes may be involved in neurologic disease. Knowledge about HIV-1 has rapidly increased, and investigators have characterized its structure, ways in which it infects cells, replicates and is cytopathic for certain cells, and how the immune system responds to it. The ideal vaccine would prevent adsorption of the virus into the cell, but it is difficult to develop stable resistance because the virus has many antigenic patterns and mutates frequently. The results of vaccine trials in animals have not been promising, but work is being done with monoclonal antibodies. Antiviral therapies being investigated include those to prevent virus binding and entry, to inhibit reverse transcription, to inhibit the virus's life cycle and to restore immune competence in immunocompromised patients.