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Summary: Background: Obesity, assessed by body mass index (BMI), is an established risk factor for 13 cancers. We aimed to identify further potential obesity-related cancers and to quantify their association with BMI relative to that of established obesity-related cancers. Methods: Using Cox regression models on 4,142,349 individuals in Sweden (mean age 27.1 years at weight measurement), we calculated hazard ratios (HRs) for the association between BMI and the risk of 122 cancers and cancer subtypes, grouped by topography and morphology. Cancers with a positive association (i.e., HR >1) at an α-level of 0.05 for obesity (BMI ≥30 kg/m2) vs. normal weight (BMI 18.5–24.9 kg/m2) or per 5 kg/m2 higher BMI, for which obesity is not an established risk factor, were considered potentially obesity related. Findings: After 100.2 million person-years of follow-up, 332,501 incident cancer cases were recorded. We identified 15 cancers in men and 16 in women as potentially obesity related. These were cancers of the head and neck, gastrointestinal tract, malignant melanoma, genital organs, endocrine organs, connective tissue, and haematological malignancies. Among these, there was evidence of differential associations with BMI between subtypes of gastric cancer, small intestine cancer, cervical cancer, and lymphoid neoplasms (P values for heterogeneity in HRs

ABSTRACTArctic miners face significant risks from diesel exhaust and dust exposure, potentially leading to adverse respiratory health. Employers must limit harmful exposures, using personal protective equipment (PPE) as a last line of defense. This study explored the association between reported respiratory exposure and symptoms, and PPE training and usage. Data from the MineHealth study (2012–2014) included a total of 453 Arctic open pit miners in Norway, Sweden, and Finland. Participants answered questions on exposure to dust and diesel exhaust, respiratory symptoms, and PPE use, in addition to age, gender, BMI, smoking, and self-rated health. Estimated exposure to dust was common, reported by 91%, 80%, and 82% and that of diesel exhaust by 84%, 43%, and 47% of workers in Sweden, Finland, and Norway, respectively. Reported dust exposure was significantly related to respiratory symptoms (OR 2.2, 95% CI 1.3–3.7), diesel exposure increased the occurrence of wheezing (OR 2.6, 95% CI 1.3–5.4). PPE use varied between the studied mines. Non-use was common and related to reduced visibility, wetness, skin irritation and fogging of the respiratory PPE. Future research should employ more precise exposure assessment, respiratory function as well as explore the reasons behind the non-compliance of PPE use.

ABSTRACTThe literature on Raynaud’s phenomenon (RP) in the feet is scarce, especially in the occupational setting. The primary aim of our study was to investigate the occurrence of RP in the feet of miners. As part of the MineHealth project, written surveys and clinical examinations were completed by 260 Arctic open-pit miners working in northern Sweden and Norway (participation rate 53.6%). Data on RP were collected using standardised colour charts and questionnaire items. Clinical examination included assessing the perception of vibration and pain in both feet. There were eight women and three men who reported RP in the feet. Four also had RP in their hands but none acknowledged any first-degree relatives with the condition. Nine reported exposure to foot-transmitted vibration and one to hand-arm vibration. Seven showed signs of neurosensory injury in the feet. To conclude, the occurrence of RP in the feet of miners was 4.4%. Most cases with RP in the feet did not report the condition in the hands and were exposed to vibration transmitted directly to the feet. There were no reports of a hereditary component. Most cases with RP in the feet also had clinical findings suggestive of peripheral neuropathy in the feet.

Purpose The Obesity and Disease Development Sweden (ODDS) study was designed to create a large cohort to study body mass index (BMI), waist circumference (WC) and changes in weight and WC, in relation to morbidity and mortality.Participants ODDS includes 4 295 859 individuals, 2 165 048 men and 2 130 811 women, in Swedish cohorts and national registers with information on weight assessed once (2 555 098 individuals) or more (1 740 761 individuals), in total constituting 7 733 901 weight assessments at the age of 17–103 years in 1963–2020 (recalled weight as of 1911). Information on WC is available in 152 089 men and 212 658 women, out of whom 108 795 have repeated information on WC (in total 512 273 assessments). Information on morbidity and mortality was retrieved from national registers, with follow-up until the end of 2019–2021, varying between the registers.Findings to date Among all weight assessments (of which 85% are objectively measured), the median year, age and BMI (IQR) is 1985 (1977–1994) in men and 2001 (1991–2010) in women, age 19 (18–40) years in men and 30 (26–36) years in women and BMI 22.9 (20.9–25.4) kg/m2 in men and 23.2 (21.2–26.1) kg/m2 in women. Normal weight (BMI 18.5–24.9 kg/m2) is present in 67% of assessments in men and 64% in women and obesity (BMI≥30 kg/m2) in 5% of assessments in men and 10% in women. The median (IQR) follow-up time from the first objectively measured or self-reported current weight assessment until emigration, death or end of follow-up is 31.4 (21.8–40.8) years in men and 19.6 (9.3–29.0) years in women. During follow-up, 283 244 men and 123 457 women died.Future plans The large sample size and long follow-up of the ODDS Study will provide robust results on anthropometric measures in relation to risk of common diseases and causes of deaths, and novel findings in subgroups and rarer outcomes.

Healthcare employees are experiencing poor wellbeing at an increasing rate. The healthcare workforce is exposed to challenging tasks and a high work pace, a situation that worsened during and after the COVID-19 pandemic. In turn, exposure to these high demands contributes to poor health, increased turnover, reduced job satisfaction, reduced efficacy, and reduced patient satisfaction and safety. Therefore, it is imperative that we identify measures to mitigate this crisis. One piece of this puzzle is how to implement sustainable tools and processes to improve the work environment of healthcare organizations. In this paper, we present the study protocol for the outlining and piloting of a joint training for pairs of healthcare line managers and their associated health and safety representatives in a Swedish healthcare organization. The objective of the training is to aid and advance the implementation of interventions to improve the work environment at the unit level. Following recommendations in the literature, the training is based on a stepwise approach that considers the specific context and focuses on the involvement of employees in creating interventions based on their needs. A central component of the training is the development of the pairs’ collaboration in prioritizing, developing, implementing, and evaluating the interventions. The training is based on an on-the-job train-the-trainer approach in which participants are progressively trained during four workshops in the steps of a participatory intervention process. Between these workshops, the pairs follow the same progressive steps together with their employees to develop and implement interventions at their unit. The pilot will involve four pairs (i.e., eight participants) representing different parts and functions of the organization and will be conducted over a period of three months. We will use a mixed method design to evaluate preconditions, the process, and proximal transfer and implementation outcome factors of the training. The overall aim of the pilot is to appraise its feasibility and be able to adjust the training before a potential scale-up.

OBJECTIVE: Retinal detachment (RD) has been associated with exposure to heavy lifting. Many occupations within the construction industry are likely to involve lifting tasks. We investigated the association between occupational heavy lifting and rhegmatogenous RD in a retrospective cohort study of Swedish construction workers. METHODS: We studied Swedish construction workers who participated in an industry-wide health and safety program from 1971 to 1993. Individual occupation codes were linked to a job exposure matrix, assigning intensity of exposure to heavy lifting to each worker. The Swedish National Patient Register was used to identify cases of RD that occurred during follow-up through the end of 2012. We used Poisson regression modeling to calculate incidence rates of RD associated with heavy lifting, age and other covariates. A subcohort of those age ≤25 years at enrollment was studied to reduce bias from missing exposure information from work prior to enrollment. RESULTS: Of 256 241 construction workers, 17% were classified with high exposure to heavy lifting in their occupation. Within the cohort, 1588 cases of RD were identified. Average exposure intensity of heavy lifting was not associated with risk of RD. However, RD risk increased with increasing cumulative exposure to heavy lifting, both in the full cohort and subcohort of those who were ≤25 years old at entry into the construction-worker cohort. CONCLUSION: Construction workers’ risk of RD appeared to increase with time spent exposed to heavy lifting.

Modern gearing applications, in particular electrification, impose new challenges in many different fields of engineering and research. In specific, new demands are imposed on gears, including higher rotational speed, lower noise acceptance, and increased efficiency, as well as increased resistance against pitting and scuffing. To meet these demands, a better understanding of gear contacts is needed. The Eurostars project Effigears proposes a novel multi-perspective methodology for assessment of gear efficiency and contact analysis. The methodology consists of using a novel surface treatment method, Triboconditioning®, implemented in a streamfinishing process, surface measurements using a scattered light method, experimental testing using the standardized FZG test rig, and contact simulations using a novel thermal elasto-hydrodynamic lubrication tool. It is found, in preliminary tests, that enhanced gear performance may be enhanced due to Triboconditioning® surface treatment. Findings also include better understanding of how surface characteristics and lubricants affect scuffing and pitting, and the effect of load distribution on gearset behavior.

ABSTRACTThis cross-sectional study aimed to describe exposure to cold climate and hand-arm vibration (HAV) as well as neurosensory and vascular symptoms and clinical findings among open-pit Arctic miners. It was based on data from questionnaires and physical examinations, including 177 men and 75 women from two open-pit mines in Sweden and Norway (response rate 54%). Working outdoors or in an unheated building or machine for at least two hours per day was reported by 44% and HAV exposure of the same duration by 10%. Neurosensory symptoms (e.g. reduced perception of touch) in the hands were reported by 47% and Raynaud’s phenomenon by 14%. In brief conclusion, the study showed that Arctic miners were commonly exposed to both cold temperatures and HAV. They also reported a broad range of neurosensory and vascular symptoms in their hands and had abnormal clinical findings related to the symptoms. The results emphasise the need for additional preventive measures in this occupational setting.

OBJECTIVE: The aim of this study was to assess the association between occupational biomechanical exposures and the occurrence of surgical treatment for subacromial impingement syndrome (SIS). METHODS: A cohort of 220 295 male constructions workers who participated in a national occupational health surveillance program (1971–1993) were examined prospectively over a 16-year follow-up period (2001–2016) for surgically treated SIS. Worker job title, smoking status, height, weight, and age were registered on health examination. Job titles were mapped to 21 occupational groups based on tasks and training. A job exposure matrix (JEM) was developed with exposure estimates for each occupational group. Surgical cases were determined through linkage with the Swedish national in- and outpatient registers. Poisson regression was used to assess the relative risks (RR) for each biomechanical exposure. RESULTS: The total incidence rate of surgically treated SIS over the 16-year observation period was 201.1 cases per 100 000 person-years. Increased risk was evident for workers exposed to upper-extremity loading (push/pull/lift) (RR 1.45–2.30), high hand grip force (RR 1.47–2.23), using handheld tools (RR 1.52–2.09), frequent work with hands above shoulders (RR 1.62–2.11), static work (RR 1.77–2.26), and hand-arm vibration (RR 1.78–2.13). There was an increased risk for SIS surgery for all occupational groups (construction trades) compared with white-collar workers (RR 1.56–2.61). CONCLUSIONS: Occupational upper-extremity load and posture exposures were associated with increased risk for surgical treatment of SIS, which underlines the need for reducing workplace exposures and early symptom detection in highly exposed occupational groups.

Besides friction and wear, airborne particle emission has become a central parameter when evaluating disc brake performance due to its potential adverse health effects as component of ambient air pollution. The pad friction material of brake system is composed of a mixture of ingredients grouped into four material categories: abrasives, reinforcing fibres, lubricants, and fillers. Some other ingredients which do not typically belong to aforementioned categories can be attributed to “fixed material”, such as aramid fibre, which is usually added into brake pad to harmonize the overall tribological properties. There is a gap of knowledge about how one ingredient from one category contributes to the emissions of particle number (PN) and mass (PM2.5, PM10). To investigate this, one ingredient from each category was chosen and produced as pins. As a reference, pins made of a commercial European brake friction material were also produced. The pins were tested using a pin-on-disc tribometer designed for airborne emission studies. Coefficient of friction, particle mass and number concentrations were measured during the tests. The results indicate that the abrasive and metal fibre have PN, PM2.5, and PM10 emission factors that are orders of magnitude higher than the lubricant and aramid fibre.

Abstract Background Raynaud’s phenomenon is common condition, but little is known about the natural course. The primary aim of this study was to determine the incidence, remission, and persistence proportions of Raynaud’s phenomenon in the general population of northern Sweden. Secondary aims were to determine how individual and exposure factors affect the course of Raynaud’s phenomenon, and to assess gender differences. Methods A prospective, survey-based, closed-cohort study was conducted on a sample of men and women between 18–70 years of age, living in northern Sweden. Data on Raynaud’s phenomenon characteristics and general health status were collected during the winters of 2015 (baseline) and 2021 (follow-up). Rates of incidence, remission, and persistence were calculated. Binary logistic regression was used to determine the association between baseline variables and the course of Raynaud’s phenomenon. Results: The study population consisted of 2703 women (53.9%) and 2314 men. There were 390 women (14.5%) and 290 men (12.7%) reporting Raynaud’s phenomenon in the follow-up survey. The annual incidence proportion was 0.7% among women and 0.9% among men (gender difference p = 0.04). The annual remission proportion was 4.4% and 5.5%, respectively (p = 0.05). Having sustained a cold injury affecting the hands since baseline was significantly associated with incident Raynaud’s phenomenon (OR 3.92; 95% CI 2.60–5.90), after adjusting for age and gender. Conclusions In the general population of northern Sweden, Raynaud’s phenomenon is a common but variable condition, where symptoms may remit over time. Men had a higher incidence proportion than women. The results support a possible causal pathway where cold injury can precede the onset of Raynaud’s phenomenon.

Abstract Background Cold exposure is an underrecognized occupational hazard that may increase the risk of peripheral nerve entrapment. The aim of this study was to determine if self-reported occupational exposure to contact and ambient cooling was associated with symptoms of carpal tunnel syndrome (CTS). Methods In this mainly cross-sectional study, surveys were conducted on a population-based sample of men and women between 18 and 70 years of age, living in northern Sweden. Cold exposure and presence of symptoms suggestive of CTS were subjectively reported. Associations between exposure and outcome were evaluated using logistic regression. Results The study included 2,703 women and 2,314 men, with a median age of 60 years (interquartile range 19). Symptoms of CTS were reported by 453 (9.2%). Being highly occupationally exposed (almost always) to contact cooling of the hands was associated with reporting CTS (OR 3.20; 95% CI 1.62–6.33), as was ambient cooling (OR 2.00; 95% CI 1.03–3.88) and severe ambient cooling (OR 4.02 95% CI 2.09–7.71), after adjusting for age, gender, body mass index, current daily smoking, diabetes mellitus, joint disease, and hand-arm vibration exposure. The point estimates increased with longer daily exposure duration. For workers exposed to severe ambient cooling for more than half of their working hours, in addition to performing heavy manual handling every day, the OR for reporting CTS was 7.25 (95% CI 3.88–13.53), with a positive additive interaction effect (expressed as relative excess risk due to interaction) of 4.67. Conclusions Self-reported occupational exposure to contact and ambient cooling was associated with symptoms suggestive of CTS. There were statistically significant positive exposure–response patterns for time spent exposed to contact and ambient cooling at work in relation to reporting symptoms of CTS. Positive additive interaction effects between cold exposure and heavy manual handling were also found. Since there was important potential uncontrolled confounding regarding repetitive wrist movements and forceful gripping, the results need to be confirmed by other studies, preferably with longitudinal design and more detailed exposure assessment.

Abstract Objective To determine if having Raynaud’s phenomenon (RP) affects the work ability, job retainment, or occurrence of sick leave. Methods Surveys on the working-age general population of northern Sweden were conducted in 2015 and 2021, gathering data on RP, occupation and sick leave. Work ability was assessed using the Work Ability Score. Results The study population consisted of 2,703 women and 2,314 men, among which 390 women and 290 men reported RP at follow-up. For women, the mean [standard deviation (SD)] Work Ability Score was 8.02 (2.24) for subjects reporting RP and 7.68 (2.46) for those without RP. For men, the corresponding numbers were 7.37 (2.03) and 7.61 (2.14), respectively. Multiple linear regression did not show an association between RP status and work ability (p = 0.459 for women and p = 0.254 for men), after adjusting for age, body mass index, physical workload, cardiovascular disease, and perceived stress. Having retained the same main livelihood since baseline was reported by 227 (58.5%) women with RP, 1,163 (51.2%) women without RP, 152 (52.6%) men with RP, and 1,075 (54.1%) men without RP (p = 0.002 for women and p = 0.127 for men). At follow-up, any occurrence of sick leave during the last year was reported by 80 (21.4%) women with RP, 410 (18.6%) women without RP, 48 (17.1%) men with RP, and 268 (13.7%) men without RP (p = 0.208 for women and p = 0.133 for men). Among those reporting sick leave, the mean (SD) duration in months was 2.93 (3.76) for women with RP, 3.00 (4.64) for women without RP, 2.77 (3.79) for men with RP, and 2.91 (12.45) for men without RP (p = 0.849 for women and p = 0.367 for men). Conclusion For neither women nor men was there a significant effect of having RP on work ability. Women with RP reported a slightly higher job retainment compared to those without the condition, while there was no difference in job retainment among men. For neither gender did the presence of RP influence the occurrence of recent sick leave, nor did it affect the length of time away from work.

BackgroundOccupational cold exposure is common in Sweden but potential impacts on musculoskeletal disorders have not been thoroughly investigated. The primary aim of this study was to determine the associations between occupational contact and ambient cooling in relation to pain in the upper extremity.MethodsIn this cross-sectional study, a digital survey was conducted on a population-based sample of women and men between 24 and 76 years of age, living in northern Sweden. Occupational cold exposure, heavy manual handling, work with vibrating tools as well as the presence of upper extremity pain at different sites were subjectively reported. Associations between exposure and outcome were evaluated using multiple binary logistic regression.ResultsThe final study sample included 2,089 (54.4%) women and 1,754 men, with a mean age of 56 years. Hand pain was reported by 196 (5.2%), lower arm pain by 144 (3.8%), and upper arm pain by 451 (11.9%). Severe ambient cooling for more than half of the working time was statistically significantly associated with hand pain (OR: 2.30; 95% CI: 1.23–4.29) and upper arm pain (OR: 1.57; 95% CI: 1.00–2.47) but not lower arm pain (OR: 1.87; 95% CI: 0.96–3.65) after adjusting for gender, age, body mass index, current daily smoking, heavy manual handling, and work with vibrating tools.ConclusionsOccupational cold exposure was statistically significantly associated with hand pain and upper arm pain. Therefore, occupational cold exposure should be recognized as a potential risk factor for musculoskeletal disorders in the upper extremity.

Drag torque in a disc brake is the residual torque when the brake is not activated. This torque can adversely influence the total energy consumption, life of the brake components, and level of airborne wear particles from vehicles. Drag torque is of special interest for long haul trucking since it could have an effect of the total energy consumption. Drag torque performance of a disc brake is usually evaluated with conventional inertia dynamometers. Vibrations induced by the wheel can help to retract the pads from the disc and decrease the drag torque. It is hard to study this phenomenon with conventional inertia dynamometers since there is usually no system to induce a forced vibration on the brake. Therefore, the aim of the paper is to investigate the effect of vibrations on the drag torque for a commercial vehicle disc brake with a novel test setup. This is done by comparing test run with and without pads, forced vibrations, and pad retraction springs. The results indicate that the forced vibrations strongly affect the level of measured drag torque. In addition, the introduction of a retraction spring can reduce drag torque with more than 50% when vibrations are induced.

This systematic review covering publications in the Medline and Embase databases for the period 1946 to 2020 revealed a higher prevalence of Dupuytren’s disease among men exposed to vibration compared to men not exposed to vibration. The risk assessment, also considering the risk of bias, corresponded to a roughly doubled risk of Dupuytren’s disease when working with vibrating machines. The supplementary meta-analysis confirmed a more than doubled risk. A possible exposure–response relation was supported by the result from the meta-analysis, which showed a doubled risk for high exposure relative to low exposure.

This systematic review on radiographic hand osteoarthritis (HOA) covering publications in the databases Medline and Embase for the period 1947 to April 2021, with a final selection of 10 studies, revealed a high prevalence of hand osteoarthritis among both vibration-exposed men and non-exposed. The results show a non-significant, unadjusted risk-increase of about 50% for X-ray-diagnosed hand osteoarthritis for those who work with vibrating machinery compared to referents. The risk estimate does not provide reliable support that working with exposure from vibrating machines increases the risk of radiographic changes in the hands.

Abstract The coefficient of friction (COF) is one of the most important parameters to evaluate the performance of a brake system. To design proper brake systems, it is important to know the COF when estimating the brake force and resulting torque. It is challenging to simulate the COF since friction in disc brakes is a complex phenomenon that depends on several parameters such as sliding velocity, contact pressure, materials, and temperatures, etc. There is a lack of studies found in the literature focusing on simulation of the COF for a full brake system based on tribometer material characterization. The aim of this work is therefore to investigate the possibility to use a finite element analysis (FEA) approach combined with a COF pv-map to compute the global COF of a disc brake system. The local COF is determined from a pv-map for each local sliding velocity and contact pressure determined by the FEA. Knowing the local COF, the braking force of the entire brake system and the global COF can be evaluated. Results obtained by the simulation are compared with dyno bench test of the same brake system to investigate the validity of the simulation approach. Results show that the simulation is perfectly in line with the experimental measurements in terms of in-stop COF development, but slightly higher with a positive offset for every braking.

Due to the electrification of vehicles, new demands are being imposed on gears, which translates to the tolerances of manufacturing errors. However, not many studies treat the impact of manufacturing error combinations on the lubricant behavior of gear sets. Therefore, a simulation method is developed, including its derivation, discretization, and implementation. The method solves the thermal elasto-hydrodynamic lubrication (TEHL) problem, taking into account the varying temperature, viscosity, density, and cavitation of the lubricant. To account for manufacturing errors, the load distribution from a loaded tooth contact analysis (LTCA), developed by the authors, is used as input to the TEHL method. Comparison is made with a standard load distribution assumption, and a numerical example is used to show some preliminary results. The results show good agreement with results from other studies. It is shown that there is a great effect of manufacturing errors on the TEHL behavior, such as temperature, due to the change in load distribution such errors impose. It can be concluded that manufacturing errors of different tolerances have a great impact and that they should therefore be taken into consideration when analyzing gear set behavior and constructing gear sets for new applications.

A significant part of non-exhaust particle emissions in cities comes from the wear of vehicle components. Several studies on airborne particles from the wear of disc brakes and tires have been completed. However, few publications can be found in the scientific literature regarding airborne emissions from dry clutches used in road vehicles. With this in mind, this preliminary study designs a clutch tribometer for the generation of airborne wear particles in a controlled environment. The number concentration and the size distribution of airborne wear particles generated from a typical dry clutch used in passenger cars are investigated. The tests are run at a constant rotational speed, and normal load. The results show that the particle number concentration from dry clutches exhibits a running-in period and a steady state, similar to the particle emissions from disc brake contact. A significant number of nanoparticles (aerodynamic diameter < 100 nm) are emitted from the dry clutch contact.

OBJECTIVES: The aim of this study was to determine the association between occupational biomechanical exposures and occurrence of surgically treated ulnar nerve entrapment (UNE). METHODS: A cohort of 229 689 male construction workers who participated in a national occupational health surveillance program (1971–1993) were examined prospectively over a 13-year case ascertainment period (2001–2013) for surgically treated UNE. Job title (construction trade), smoking status, height, weight and age were recorded on examination. Job titles were merged into occupational groups of workers performing similar work tasks and having similar training. Occupational biomechanical exposure estimates were assigned to each occupational group with a job exposure matrix (JEM) developed for the study. Negative binomial models were used to assess the relative risks for each biomechanical exposure and the sums of highly correlated biomechanical exposures. Surgical treatment of UNE was determined via a linkage with the Swedish Hospital Outpatient Surgery Register. RESULTS: There were 555 cases of surgically treated UNE within the cohort. Workers exposed to forceful hand-grip factors had a 1.4-fold higher relative risk (95% CI 1.18–1.63) of undergoing surgical treatment for UNE compared to unexposed workers. Occupational groups comprising workers exposed to forceful hand-grip work showed the highest risks for UNE and included concrete workers, floor layers, ground preparatory workers, rock blasters, and sheet-metal workers. CONCLUSION: Forceful hand-grip work increases the risk for surgically treated ulnar nerve entrapment.

The coefficient of friction (COF) is one of the core factors in the evaluation of brake system performance. It is challenging to predict the COF, since it is strongly influenced by several parameters such as contact pressure (p), slip rate (v) and temperature (T) that depend on the driving conditions. There is a need for better models to describe how the brake friction varies under different driving conditions. The purpose of this research is to study the possibility of using 3D friction pvT-maps to estimate the COF of a disc brake system under different driving conditions. The 3D friction pvT-maps are created by filtering results of material tests conducted in a mini-dyno inertia bench. The COF measured under different driving cycles in an inertia dyno bench with the full brake system are compared with the COF estimated by the friction maps coming from the reduced scale dyno bench to investigate the validity of the simulation approach. This study shows that mini dyno bench is suitable to obtain a tribological characterization of the friction pad–disc rotor contact pair and is able to replace the full inertia dyno bench to investigate the brake system performance.

Objectives: To characterise cold sensitivity using a semi-structured interview, physical examination, thermal quantitative sensory testing (QST), and laser speckle contrast analysis (LASCA). Methods: Eight women and four men, ages 22–74, with cold sensitivity were interviewed and examined by an occupational physician. Thermal perception thresholds were established using QST, on the pulp of the index and little finger of the most affected hand. Skin perfusion in the dorsum of the hand was measured using LASCA, at baseline, after two-minute 12°C water immersion, and during rewarming. Results: The physical examination yielded few findings indicative of vascular or neurosensory pathology. One subject (8%) had impaired thermal perception thresholds. LASCA at baseline showed absent proximal-distal perfusion gradients in six subjects (50%), and a dyshomogeneous perfusion pattern in five (42%). Perfusion on a group level was virtually unchanged by cold stress testing (median 52.5 PU; IQR 9.0 before versus 51.3 PU; IQR 27.2 afterwards). Conclusions: Physical examination and thermal QST offered little aid in diagnosing cold sensitivity, which challenges the neurosensory pathophysiological hypothesis. LASCA indicated disturbances in microvascular regulation and could prove a useful tool in future studies on cold sensitivity.

The coefficient of friction (COF) is an important parameter when evaluating brake system performance. It is complex to predict friction due to its dependence on parameters, such as sliding velocity, contact pressure, temperature, and friction material mixtures. The aim of this work is to evaluate the macroscopic COF of a disc brake system under specific braking conditions by a meso-scale approach, using a cellular automaton simulation where the friction material mixture is modelled starting from its basic components. The influence of the local components in contact is taken into account. Simulated COF values are in line with the experimental values.

Disc brake creep groan is a stick-slip phenomenon which results in a low frequency noise in road vehicles that could occur at low vehicle speeds and brake torques. Simulation approaches are used predict the stick-slip phenomena for disc brakes. These approaches depend on the friction model used. Tribometers can be used to map how the local coefficient of friction (CoF) depends on the contact pressure (p) and sliding speed (v). A CoF pv-map can be used as friction model in simulation approaches. There is a lack of CoF maps at low contact pressures and sliding speeds are reported in the literature. The aim of the presented study is to map the CoF for a disc brake material combination at low contact pressures (0.03–0.28 MPa) and sliding speeds (0–3.8 mm/s). The result shows that the friction decreases with increased contact pressure and sliding speed for the specific material combination tested and the test conditions used. More studies are needed to further investigate the validity of the results. Keywords: Friction, Disc brake, Low speed, Low pressure

Laser cladding is a promising surface treatment for refurbishing worn-out cast-iron brake rotors. Previous studies on laser-cladded brake rotors have demonstrated their extensively higher wear and greater airborne particle emissions, compared with traditional cast iron rotors. In order to overcome this, a commercial non-asbestos organic (NAO) brake material is tested against Fe-based laser-cladded and traditional cast-iron brake rotors. Two low-metallic brake pad materials are also tested as references. The materials’ coefficients of friction, specific wear rates and particle number concentrations are evaluated. The results indicate that the NAO brake material showed lower wear and had fewer particle emissions than the low-metallic brake materials when deployed against both cast iron and laser-cladded brake rotors. The NAO/laser-cladding friction pairing showed wear, particle concentration and fraction of fine particles (sub 1 μm) equivalent to those of the low-metallic/cast-iron friction pairing, creating significant potential for application in refurbishing worn-out cast-iron brake rotors.

Non-exhaust emissions, generated by the wear of brake systems, tires, roads, clutches, and road resuspension, are responsible for a large part of airborne pollutants in urban areas. Brake wear accounts for 55% of non-exhaust emissions and significantly contributes to urban health diseases related to air pollution. A major part of the studies reported in the scientific literature are focused on experimental methods to sample and characterize brake wear particles in a reliable, representative, and repeatable way. In this framework, simulation is an important tool, which makes it possible to give interpretations of the experimental results, formulate new testing approaches, and predict the emission produced by brakes. The present comprehensive literature review aims to introduce the state of the art of the research on the different aspects of airborne wear debris resulting from brake systems which can be used as inputs in future simulation models. In this review, previous studies focusing on airborne emissions produced by brake systems are investigated in three main categories: the subsystem level, system level, and environmental level. As well as all the information provided in the literature, the simulation methodologies are also investigated at all levels. It can be concluded from the present review study that various factors, such as the uncertainty and repeatability of the brake wear experiments, distinguish the results of the subsystem and system levels. This gap should be taken into account in the development of future experimental and simulation methods for the investigation of airborne brake wear emissions.

Objectives: This cross-sectional questionnaire study was carried out at 4 open-pit mines in Finland, Norway, Russia and Sweden as part of the MineHealth project. The aim has been to compare the prevalence of musculoskeletal symptoms between drivers of mining vehicles and non-drivers. Material and Methods: The mine workers were asked whether they had suffered from any musculoskeletal symptoms during the previous 12 months in specified body regions, and to grade the severity of these symptoms during the past month. They were also asked about their daily driving of mining vehicles. Results: The questionnaire was completed by 1323 workers (757 vehicle drivers) and the reported prevalence and severity of symptoms were highest for the lower back, followed by pain in the neck, shoulder and upper back. Drivers in the Nordic mines reported fewer symptoms than non-drivers, while for Russian mine workers the results were the opposite of that. The daily driving of mining vehicles had no significant association with the risk of symptoms. Female drivers indicated a higher prevalence of symptoms as compared to male drivers. Conclusions: The study provided only weak support for the hypothesis that drivers of vehicles reported a higher prevalence of musculoskeletal symptoms than non-vehicle drivers. There were marked differences in the prevalence of symptoms among workers in various enterprises, even though the nature of the job tasks was similar. Int J Occup Med Environ Health 2017;30(4):553–564

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OBJECTIVE: This study aimed to examine the effects of 14 months of military training comprising cold winter conditions on neurosensory and vascular function in the hands and feet. METHODS: Military conscripts (N=54) were assessed with quantitative sensory testing comprising touch, temperature, and vibration perception thresholds and finger systolic blood pressure (FSBP) after local cooling and a questionnaire on neurosensory and vascular symptoms at both baseline and follow-up. Ambient air temperature was recorded with body worn temperature loggers. RESULTS: The subjects showed reduced sensitivity to perception of touch, warmth, cold and vibrations in both the hands and feet except from vibrotactile perception in digit two of the right hand (right dig 2). Cold sensations, white fingers, and pain/discomfort when exposed to cold as well as pain increased in both prevalence and severity. There were no statistically significant changes in FSBP after local cooling. CONCLUSION: Fourteen months of winter military training comprising cold winter conditions reduced sensation from touch, warmth, cold, and vibrotactile stimulus in both hands and feet and increased the severity and prevalence of symptoms and pain. The vascular function in the hands, measured by FSBP after local cooling, was not affected.

Non-exhaust wear emissions from disc brakes affect the air quality in cities throughout the world. These emissions come from the wear of the contact surfaces of both the pads and disc. The tribological and emissions performance of disc brakes strongly depend on the contact surface characteristics of the pads and discs. The surfaces of conventional pads are scorched by heating it to several hundred degrees to make the resin carbonize down to a few millimetres deep into the pad. This is done to have a shorter run-in period for new pads. It is not known how scorching will affect the amount of airborne particle emissions. Therefore, the aim of the present study is to investigate how pad scorching influence the airborne particle emissions. This is done by comparing the pin-on-disc tribometer and inertia dyno bench emission results from a Cu-free friction material run against a grey cast iron disc. Three types of modified friction material surfaces have been tested: scorched, extra-scorched and rectified. The results show that the level of scorching strongly affects the airborne particle emissions in the initial phase of the tests. Even if the scorched layer is removed (rectified) before testing, it seems like it still has a measurable influence on the airborne particle emissions. The results from the tribometer tests are qualitatively in line with the inertia dyno bench test for about the first forty brake events; thereafter, the airborne particle emissions are higher for the scorched pads. It can be concluded that it seems that the level of scorching has an adverse influence on both the tribological performance and level of particle emissions.

Increased occurrence of Raynaud's phenomenon, neurosensory injury and carpal tunnel syndrome has been reported for more than 100 years in association with work with vibrating machines. The current risk prediction modelling (ISO-5349) for "Raynaud's phenomenon" is based on a few studies published 70 to 40 years ago. There are no corresponding risk prediction models for neurosensory injury or carpal tunnel syndrome, nor any systematic reviews comprising a statistical synthesis (meta-analysis) of the evidence.Our aim was to provide a systematic review of the literature on the association between Raynaud's phenomenon, neurosensory injuries and carpal tunnel syndrome and hand-arm vibration (HAV) exposure. Moreover the aim was to estimate the magnitude of such an association using meta-analysis.This systematic review covers the scientific literature up to January 2016. The databases used for the literature search were PubMed and Science Direct. We found a total of 4,335 abstracts, which were read and whose validity was assessed according to pre-established criteria. 294 articles were examined in their entirety to determine whether each article met the inclusion criteria. The possible risk of bias was assessed for each article. 52 articles finally met the pre-established criteria for inclusion in the systematic review.The results show that workers who are exposed to HAV have an increased risk of vascular and neurological diseases compared to non-vibration exposed groups. The crude estimate of the risk increase is approximately 4-5 fold. The estimated effect size (odds ratio) is 6.9 for the studies of Raynaud's phenomenon when including only the studies judged to have a low risk of bias. The corresponding risk of neurosensory injury is 7.4 and the equivalent of carpal tunnel syndrome is 2.9.At equal exposures, neurosensory injury occurs with a 3-time factor shorter latency than Raynaud's phenomenon. Which is why preventive measures should address this vibration health hazard with greater attention.

OBJECTIVES: This study compared the cost efficiency of observation and inclinometer assessment of trunk and upper-arm inclination in a population of flight baggage handlers, as an illustration of a general procedure for addressing the trade-off between resource consumption and statistical performance in occupational epidemiology. METHODS: Trunk and upper-arm inclination with respect to the line of gravity were assessed for three days on each of 27 airport baggage handlers using simultaneous inclinometer and video recordings. Labor and equipment costs associated with data collection and processing were tracked throughout. Statistical performance was computed from the variance components within and between workers and bias (with inclinometer assumed to produce “correct” inclination angles). The behavior of the trade-off between cost and efficiency with changed sample size, as well as with changed logistics for data collection and processing, was investigated using simulations. RESULTS: At similar total costs, time spent at trunk and arm inclination angles >60 ° as well as 90^th percentile arm inclination were estimated at higher precision using inclinometers, while median inclination and 90th percentile trunk inclination was determined more precisely using observation. This hierarchy remained when the study was reproduced in another population, while inclinometry was more cost-efficient than observation for all three posture variables in a scenario where data were already collected and only needed to be processed. CONCLUSIONS: When statistical performance was measured only in terms of precision, inclinometers were more cost-efficient than observation for two out of three posture metrics investigated. Since observations were biased, inclinometers consistently outperformed observation when both bias and precision were included in statistical performance. This general model for assessing cost efficiency may be used for designing exposure assessment strategies with considerations not only of statistical but also cost criteria. The empirical data provide a specific basis for planning assessments of working postures in occupational groups.

Copper from vehicles disc brakes is one main contributor of the total copper found in the environment. Therefore, the U.S. Environmental Protection Agency (EPA) and the automotive industries started the Copper-Free Brake Initiative. The pad friction material is essentially composed of a binder, fillers, reinforcing fibres and frictional additives. Copper and brass fibres are the most commonly used fibres in brake pads. There is a need to understand how the contact temperature distribution will change if copper-based fibres are changed to steel fibres. The aim of this work is, therefore, to investigate how this change could influence the local contact temperatures. This is done by developing a multi-scale simulation approach which combines cellular automaton, finite element analysis (FEA) and computational fluid dynamics (CFD) approaches with outputs from inertia brake dyno bench tests of Cu-full and Cu-free pads. FEA and thermal-CFD are used to set the pressure and the temperature boundary conditions of the cellular automaton. The outputs of dyno tests are used to calibrate FEA and CFD simulations. The results of the study show lower peaks in contact temperature and a more uniform temperature distribution for the Cu-free pad friction material.

Brake-related airborne particulate matter contributes to urban emissions in the transport sector. Recent research demonstrated a clear dependence of the number of ultra-fine particles on the disc brake temperature. Above the so-called transition temperature, the number of ultra-fine particles increases dramatically (several magnitudes). As for exhaust emissions, part of the emissions released during braking can be in the volatile fraction. For this reason, a disc brake test stand specifically designed for aerosol research was equipped with three different aerosol sampling instruments: (i) a standard cascade impactor, (ii) a cascade impactor operating at high temperature with a heated sampling line, and (iii) a standard cascade impactor with a thermodenuder. Tests with a brake assembly representative of European passenger vehicles were executed, and the concentration of released airborne particles was determined. The results showed a decrease by several magnitudes in the concentration (in the size range of below 200 nm) using the cascade impactor operating at 180 °C with the sampling line heated to 200 °C. A further decrease in the concentration of airborne particles with size fractions below 200 nm was measured using a standard cascade impactor with a thermodenuder heated to 300 °C.

Airborne particulate emissions originating from the wear of pads and rotors of disc brakes contribute up to 50% of the total road emissions in Europe. The wear process that takes place on a mesoscopic length scale in the contact interfaces between the pads and rotors can be explained by the creation and destruction of contact plateaus. Due to this complex contact situation, it is hard to predict how changes in the wear and material parameters of the pad friction material will affect the friction and wear emissions. This paper reports on an investigation of the effect of different parameters of the pad friction material on the coefficient of friction and wear emissions. A full factorial design is developed using a simplified version of a previously developed cellular automaton approach to investigate the effect of four factors on the coefficient of friction and wear emission. The simulated result indicates that a stable third body, a high specific wear, and a relatively high amount of metal fibres yield a high and stable mean coefficient of friction, while a stable third body, a low specific wear, a stable resin, and a relatively high amount of metal fibres give low wear emissions.

OBJECTIVES: The aim of this study was to examine the association between white fingers, cold environment, and exposure to hand–arm vibration (HAV). The hypothesis was that working in cold climate increases the risk of white fingers. METHODS: The occurrence of white fingers was investigated as a cross-sectional study in a cohort of Swedish male construction workers (N=134 757). Exposure to HAV was based on a job-exposure matrix. Living in the north or south of Sweden was, in a subgroup of the cohort, used as an indicator of the exposure to cold environment (ie, living in the north meant a higher exposure to cold climate). The analyses were adjusted for age and use of nicotine products (smoking and snuff). RESULTS: HAV-exposed workers living in a colder climate had a higher risk for white fingers than those living in a warmer climate [odds ratio (OR) 1.71, 95% confidence interval (95% CI) 1.42–2.06]. As expected, we found that HAV-exposed workers had an increased risk compared to controls (OR 2.02, 95% CI 1.75–2.34). The risk for white fingers increased with increased level of exposure to HAV and also age. CONCLUSIONS: Cold environment increases the risk for white fingers in workers occupationally exposed to HAV. The results underscore the need to keep exposure to HAV at workplaces as low as possible especially in cold climate.