Friction measurements on ramps using the Brungraber Mark II slipmeter

It is a common belief that a person is more likely to slip when walking on an inclined surface than when walking on a level surface. Reports of friction measurements were common on horizontal surfaces but were rare on inclined surfaces. A slip measurement device reports different readings on the same surface with different inclined angles if the effect of gravity comes into play. In this study, friction measurements were conducted on the same surface with 0°, 10° and 20° inclined angles under different footwear materials, floors, and surface conditions, using a Brungraber Mark II slipmeter. Statistically significant results were obtained for the measurement results under the inclined angle, footwear material, floor, and surface conditions. A regression model was established to describe the coefficients of friction on ramp floors under footwear material/floor/surface conditions. This model is significant at p < 0.0001 with an R² of 0.87. The cosine function of ramp angle, as suggested in the regression model, was recommended to be used as a correcting factor for friction measurement results using the Brungraber Mark II on ramps to report the corrected friction coefficient of the surfaces.     

Safety compliance climate concerning risk assessment and preventive measures in EU legislation: A Finnish survey

The aim of the present study is to explore the process dynamics of the safety compliance climate and work relationships, including their antecedents and consequences. After investigating the many dimensions of safety compliance climate and of work relationships, the study concludes that a multi-component measure is needed to fully assess all of their dimensions. With respect to the impacting positively on safety compliance legislation, the present study found the following factors: “contribution measures”, “concrete preventive measures” and “risk assessment process”. For risk assessment factors on safety compliance the study identified “planning, guidelines, policy, management”, “prioritization of proactive measures”, “results in cooperation and information” and “active use of risks assessment document”. In a regression model for the workers, both risk assessment process and contribution measures had a statistically highly significant (p < 0.001) effect on concrete preventive measures. In the regression analysis of the employers risk assessment process had a statistically significant (p < 0.01) effect and contribution measures had a statistically highly significant (p < 0.001) effect on concrete preventive measures.     

Friction measurements on “anti-slip” floors under shoe sole,contamination, and inclination conditions

Friction measurements were conducted to study the effects of shoe sole, floor, contamination, and inclined angle of the floor surface on friction coefficient. The shoe sole samples included composite rubber outsole samples with and without V-shaped tread design. Unglazed ceramic tiles of both flat and tiles with molded profile design were tested. The contamination conditions included dry, wet, and glycerol-contaminated conditions. The inclined angles included 0°, 5°, and 10°. A Brungraber Mark II slipmeter was used. The results showed that all the four factors affected friction coefficient significantly (p < 0.0001). Flat rubber soles had higher friction coefficients than the soling samples with V-shaped tread design on all tested floors and inclined angles under wet conditions. Flat soles, however, had extremely low friction when tested on flat floors under glycerol-contaminated conditions. The floors with molded grooves perpendicular to friction measurement direction had the highest friction coefficients than all other floor conditions under both the wet and glycerol-contaminated conditions except the wet/flat sole/10° condition. A regression model with a cosine function was established to describe the relationship between friction coefficient and inclined angle of the floor under the experimental conditions. This model is statistically significant at p < 0.0001 with an R² of 0.97.     

Driving and telephoning: Relative accident risk when using hand-held and hands-free mobile phones

Experimental research shows that using mobile phones while driving leads to impaired driving, and it has been suggested that this driving impairment to a large extent is a result of cognitive, rather than physical, distractions. This notion is partly supported by empirical data showing that use of hands-free phones is associated with impaired driving in much the same way as use of hand-held phones. In the present study, accident risk when using hand-held and hands-free phones was investigated in a sample of 4307 drivers who were involved in accidents in 2007. In addition, data from a similar survey from 1997 (N = 5007) were used in order to get more observations. Relative risk was estimated using “quasi-induced exposure” in multiple-vehicle accidents. Results from the two surveys combined showed a significant increase in accident risk for hand-held mobiles and for hand-held and hands-free phones together. A non-significant tendency towards increased risk for hands-free mobiles was also detected. However, analyses of data from 2007 separately did not result in statistically significant relative risk estimates for any of the mobile types. Hand-held users were more inclined to attribute the accident to mobile phone use than were hands-free users.     

Experimental investigation on the impact sensitivity of a match head composition influenced by the surface roughness of in-process contact materials

This study is aimed to investigate the influence of contact materials and their surface roughness on impact sensitivity of a match head composition. It was found that there were variations to the impact sensitivity, ranging from 2 to 14.7 J. The sensitivity response was quicker in case of steel–steel anvil combinations than with aluminium–aluminium anvil and brass–brass anvil combinations. The match head composition was found to be highly hazardous at the surface roughness values of 1.67, 1.80, and 1.60 μm for steel, aluminium and brass material surfaces, respectively. Such data are not available hitherto.     

Unintentional injuries treated in hospital emergency departments among persons aged 65 years and older,United States, 2006–2011

IntroductionWith the aging of the United States population, unintentional injuries among older adults, and especially falls-related injuries, are an increasing public health concern.MethodsWe analyzed emergency department (ED) data from the Nationwide Emergency Department Sample, 2006–2011. We examined unintentional injury trends by 5-year age groups, sex, mechanism, body region, discharge disposition, and primary payer. For 2011, we estimated the medical costs of unintentional injury and the distribution of primary payers, plus rates by injury mechanisms and body regions injured by 5-year age groups.ResultsFrom 2006 to 2011, the age-adjusted annual rate of unintentional injury-related ED visits among persons aged ≥ 65 years increased significantly from 7987 to 8163, per 100,000 population. In 2011, 65% of injuries were due to falls. Rates for fall-related injury ED visits increased with age and the highest rate was among those aged ≥ 100. Each year, about 85% of unintentional injury-related ED visits in this population were expected to be paid by Medicare. In 2011, the estimated lifetime medical cost of unintentional injury-related ED visits among those aged ≥ 65 years was $40 billion.ConclusionIncreasing rates of ED-treated unintentional injuries, driven mainly by falls among older adults, will challenge our health care system and increase the economic burden on our society. Prevention efforts to reduce falls and resulting injuries among adults aged ≥ 65 years have the potential to increase well-being and reduce health care spending, especially the costs covered by Medicare.Practical applicationsWith the aging of the U.S. population, unintentional injuries, and especially fall-related injuries, will present a growing challenge to our health care system as well as an increasing economic burden. To counteract this trend, we must implement effective public health strategies, such as increasing knowledge about fall risk factors and broadly disseminating evidence-based injury and fall prevention programs in both clinical and community settings.     

Perspectives on safety: The impact of group membership,work factors and trust on safety performance in UK and Norwegian drilling company employees

This study is anchored in a contractor company providing well services for platform drilling on the Norwegian (NCS) and the UK Continental Shelves (UKCS). The research project has as its point of departure the potential influences of group level characteristics, structural work factors, trust, and safety behaviour on safety performance. Do perceptions and performance differ across Shelves? Are “nomadic” groups or employees that have more unpredictable shift rotations more exposed to accidents than others? Is high trust and sound safety behaviour enhancing good safety performance? The results are based on questionnaire data from two samples of personnel distributed across three installations on the UKCS and nine on the NCS with a response rate of 67%: N = 170 (UKCS) and N = 621 (NCS). In addition, two focus group interviews were held in each country, with 15 participants in each. The results show that our model makes sense. Shelf shows a significant influence on safety performance in all but the final stage in our five-step logistic regression model, indicating that the effect may be mediated by safety compliance and safety participation. Installations and different work teams have different exposure and structural work factors matter significantly. Somewhat counter-intuitively, employees who have a “nomadic” status and who hold the least regular shift rotations appear to have a lower risk of being involved in incidents. High trust in workmates buffers against incident involvement and the same applies for high safety compliance. The results, challenges and implications for research and safety practitioners are discussed.     

Overall and local movement speeds during fire drill evacuations in buildings up to 31 stories

The time that it takes an occupant population to reach safety when descending a stairwell during building evacuations is typically described by measurable engineering variables such as stairwell geometry, speed, density, and pre-evacuation delay. In turn, engineering models of building evacuation use these variables to predict the performance of egress systems for building design, emergency planning, or event reconstruction. As part of a program to better understand occupant movement and behavior during building emergencies, the Engineering Laboratory at the National Institute of Standards and Technology (NIST) has been collecting stairwell movement data during fire drill evacuations of office buildings. These data collections are intended to provide a better understanding of this principal building egress feature and develop a technical foundation for future codes and standards requirements. To date, NIST has collected fire drill evacuation data in eight office building occupancies ranging from 6 to 62 stories in height that have included a range of stairwell widths and occupant densities.While average movement speeds in the current study of 0.48 m/s ± 0.16 m/s are observed to be quite similar to the range of literature values, local movement speeds as occupants traverse down the stairwell are seen to vary widely within a given stairwell, ranging from 0.056 m/s to 1.7 m/s. These data should provide confirmation of the adequacy of existing literature values typically used for occupant movement speeds or provide updated values for future analyses.     

Characterization of fall patients: Does age matter?

IntroductionEvaluating age-specific fall characteristics is important for prevention programs. The aim was to characterize fallers who presented to our trauma center. We hypothesized that fall characteristics and outcomes would vary with age.MethodsData were retrospectively collected from the trauma registry and electronic medical records during January 1st, 2014-December 31st, 2015. Data were analyzed by Chi-square test with Yates’ continuity correction and one-way ANOVA with Bonferroni’s multiple comparisons test.ResultsThere were 1541 fallers, 814 (52.8%) were male. Ages ranged from 11 months to 100 years. The admission rate was high at 86%, with an average hospital stay of 5.7 days. Patients in the 0-18 and 19-45 age groups spent significantly less time in the hospital (p < 0.0001). Elderly patients had the highest average injury severity score (p < 0.0001). However, the youngest patients required surgery more often (p = 0.0004). The overall mortality rate was 3.6% and 52.8% were male. The mortality rate increased with age, from 0% for the 0-18 age group to 6.9% for patients ≥ 65 years of age. Remarkably, fallers in the 19-45 and 46-64 age groups predominantly died from ground level falls even though the average fall height in these groups was the highest (p < 0.0001). More fallers in the 19-45 and 46-64 age groups tested positive for alcohol/drug use (p < 0.0001). Middle-aged and elderly patients were more likely to be discharged to a skilled nursing or rehabilitation facility compared to younger patients who were discharged home.Conclusions and practical applicationsFall characteristics and outcomes varied with age. Data on age-specific characteristics, outcomes, and risk factors of falls will help in developing targeted interventions and may lead to better approaches to treat patients.     

The potential impact of light emitting diode lighting on reducing mining injuries during operation and maintenance of lighting systems

Research by the US National Institute for Occupational Safety and Health (NIOSH) indicates that light emitting diodes (LEDs) can be used to enhance safety by improving a miner’s ability to see mining hazards and reducing glare. This paper investigates if LEDs provide another benefit by reducing miner exposure to hazards during maintenance and operation of LED lighting. LEDs could provide useful lives up to 50 times longer than incandescent lighting commonly used in mining and could enable design changes to reduce certain hazards. The mining accident records compiled by the Mine Safety and Health Administration (MSHA) were examined to determine the extent and nature of accidents involving the maintenance and operation of mine luminaries. A total of 140 relevant accident records were found for the years 2002–2006. These incidents resulted in 3668 days lost from work with an additional 925 days of restricted activity. The injury narratives were studied to determine if the implementation of LED-based luminaries could reduce injury severity and frequency. The greatest near-term potential impacts appear to be related to reducing maintenance and cap lamp redesign. Longer term (5 years), low-power and lightweight auxiliary LED lighting for surface mines could also have potential impact for improving safety.     

Work-related driving safety in light vehicle fleets: A review of past research and the development of an intervention framework

This paper presents a critical review of past research in the work-related driving field in light vehicle fleets (e.g., vehicles < 4.5 tonnes) and an intervention framework that provides future direction for practitioners and researchers. Although work-related driving crashes have become the most common cause of death, injury, and absence from work in Australia and overseas, very limited research has progressed in establishing effective strategies to improve safety outcomes. In particular, the majority of past research has been data-driven, and therefore, limited attention has been given to theoretical development in establishing the behavioural mechanism underlying driving behaviour. As such, this paper argues that to move forward in the field of work-related driving safety, practitioners and researchers need to gain a better understanding of the individual and organisational factors influencing safety through adopting relevant theoretical frameworks, which in turn will inform the development of specifically targeted theory-driven interventions. This paper presents an intervention framework that is based on relevant theoretical frameworks and sound methodological design, incorporating interventions that can be directed at the appropriate level, individual and driving target group.     

Flammability of hydrocarbon and carbon dioxide mixtures

The effect of carbon dioxide (CO₂) concentration on the ignition behaviour of hydrocarbon and CO₂ gas mixtures is examined in both jets and confined explosions. Results from explosion tests are presented using a 20 l explosion sphere and an 8 m long section of 1.04 m diameter pipeline. Experiments to assess the flame stability and ignition probability in free-jets are reported for a range of different release velocities. An empirically-based flammability factor model for free-jets is also presented and results are compared to ignition probability measurements previously reported in the literature and those resulting from the present tests.The results help to understand how CO₂ changes the severity of fires and explosions resulting from hydrocarbon releases. They also demonstrate that it is possible to ignite gas mixtures when the mean concentration is outside the flammable range. This information may be useful for risk assessments of offshore platforms involved in carbon sequestration or enhanced oil recovery, or in assessing the hazards posed by poorly-inerted hydrocarbon processing plant.     

Fatigue and on-duty injury among police officers: The BCOPS study

IntroductionPolicing involves inherent physical and psychological dangers as well as occupational stressors that could lead to chronic fatigue. Although accounts of adverse events associated with police fatigue are not scarce, literature on the association between chronic fatigue and on-duty injury are limited. Methods: Participants were officers from the Buffalo Cardio-Metabolic Occupational Police Stress (BCOPS) Study. A 10-item questionnaire was administered to assess how tired or energetic the officers generally felt irrespective of sleep hours or workload. The questionnaire consisted of five positively worded and five negatively phrased items that measured feelings of vigor/energy and tiredness, respectively. Total as well as separate scores for positive and negative items were computed by summing scores of individual items. Payroll records documenting each officer's work history were used to assess occurrence of injury. Poisson regression was used to estimate prevalence ratios (PR) of injury. Results: Nearly 40% of officers reported feeling drained. Overall prevalence of on-duty injury during the past year was 23.9%. Injury prevalence showed a significant increasing trend across tertiles of total fatigue score: 19.6, 21.7, and 30.8% for lowest, middle and highest tertiles, respectively (trend p-value = 0.037). After controlling for potential confounders, a 5-unit increase in total fatigue score was associated with a 12% increase in prevalence of injury which was marginally significant (p = 0.075). A 5-unit increase in fatigue score of the positively worded items was associated with a 33% increase in prevalence of injury (PR = 1.33, 95% CI: 1.04–1.70, p = 0.022). Conclusion: Officers who do not feel active, full of vigor, alert, or lively had a significantly higher prevalence of non-fatal work place injury compared to their counter parts. Practical applications: With additional prospective evidence, workplace interventions designed to enhance level of energy may reduce feelings of tiredness and hence may prevent workplace injury.     

Removal of a cationic bisbiguanide using Functionalized Activated Carbons (FACs)

Functionalized Granular Activated Carbons (FACs) are used as adsorbents for treating pharmaceutical wastewaters containing Chlorhexidine Gluconate. Chemical modifications of Granular Activated Carbons (GACs) using functionalizing agents like HCl and HF produce FACs. The adsorption capacity of each of FAC-HCl and FAC-HF is found to be higher than GAC. The modelled maximum adsorption capacity for FAC-HCl is 1.02 g/g of adsorbent, 3.49 g/g of adsorbent for FAC-HF and 0.0682 g/g of adsorbent for GAC. This is mainly due to the additional chemisorptions by surface complexation at the functionalized surface sites of the modified GACs. This is also supported by the well-known pseudo-second-order kinetic model. Formation of surface complexes with the functional groups and weakly polar Chlorhexidine Gluconate is well supported by the physical characterization using Energy dispersive X-ray spectroscopy (EDAX), Brunner–Emmett–Teller (BET) test and Fourier Transform Infrared spectroscopy (FTIR) analysis after adsorption. The adsorption capacity of GAC and the FACs increases in the order of FAC-HF > FAC-HCl > GAC conforming to the proportion of the total acidity of the carbon surfaces. Intra-particle diffusion is not the sole rate-controlling factor. An agreement to pseudo-second-order kinetic model, Elovich kinetic model and Boyd's film diffusion model proves that chemisorption is the rate-controlling parameter in this adsorption study.     

Sensitivity analysis and optimization for gasoline vapor condensation recovery

Volatile organic compounds (VOCs) are easily evaporated and discharged from everywhere into the atmosphere, especially in various operations of gasoline. The emission of VOCs is always a significant environmental problem, and the control of VOCs pollution has been a hot topic in the field of air purification. In this paper, the condensation separation method for gasoline vapor recovery was investigated and four gasoline vapors of S1–S4 were selected for the sensitivity analysis and optimization of the condensation process, using the Model Analysis Tools from Aspen Plus. Generally, to control VOCs pollution efficiently, both the vapor recovery efficiency and the outlet vapor concentration of the condensation recovery system should be simultaneously considered. Then an optimized three-stage condensation process was proposed, whose condensation temperatures were optimized and designed at 1 °C, −40 °C and −110 °C, respectively. Further, based on the comprehensive consideration of both meeting the more strict VOCs emission standard and ensuring the condensation recovery system work stably and economically, it was recommended that the maximum total vapor recovery efficiencies for S1–S4 should be 99.73%, 99.79%, 99.82% and 99.19%, and the minimum outlet vapor concentrations be 2.87 g/m³, 2.75 g/m³, 3.04 g/m³ and 16.98 g/m³, respectively. Accordingly, the condensation temperature of the copious cooling stage should be set at −130 °C. Moreover, the total cooling duties for the single-stage and three-stage condensation processes were investigated and compared when the condensation temperature of the recovery system ranged from 20 °C to −110 °C. The total cooling duties of the three-stage condensation process for S1–S4 would be saved by 12.23%, 15.68%, 13.96% and 15.65%, respectively. Finally, a three-stage condensation system was developed for the industrial gasoline vapor recovery, which has performed well since its installation.     

Electrostatic ignition of sensitive flammable mixtures: Is charge generation due to bubble bursting in aqueous solutions a credible hazard?

Experiments have been conducted to gain insight into the credibility of sparging aqueous solutions as an electrostatic ignition hazard for sensitive hydrogen/air or fuel/oxygen mixtures (Minimum Ignition Energies of ∼0.017 mJ and ∼0.002 mJ, respectively, compared to ∼0.25 mJ for hydrocarbon/air mixtures). Tests performed in a 0.5 m³ ullage produced electric field strengths between 125 and 560 V m⁻¹ for air flows of 5–60 l min⁻¹, respectively, comprised of 2–4 mm diameter bubbles. Field strength can be related to the space charge and fitting to an exponential accumulation curve enabled the charge generation rate from the air flows to be estimated. This was observed to be directly proportional to the air flow and its magnitude was consistent with literature data for bubble bursts. The charge accumulation observed at laboratory scale would not be a cause for concern. On the basis of a simple model, the charge accumulation in a 27 m³ ullage was predicted for a range of air flows. It is apparent from such calculations that ignition of hydrocarbon/air mixtures would not be expected. However, it would seem possible that field strengths might be sufficient to cause a risk of incendive spark or corona discharges in moderately sized vessels with sensitive flammable mixtures.     

Autoignition temperature data and scaling for amide solvents

Autoignition temperature tests using the ASTM E659 test method have been conducted for N,N-dimethylacetamide (DMAC) and N,N-dimethylformamide (DMF) in test vessels with volumes of 0.5 l, 5 l, and 12 l. Tests were conducted at three different laboratories yielded good agreement (standard deviation with 5 °C) in all cases except for DMAC in the 0.5 l test vessel (standard deviation of 23 °C). Scaling correlations have been developed for the decrease of autoignition temperature with increasing volume and for increasing values of the vessel volume to surface area ratio. The variations for DMAC are steeper than the literature values for almost all other combustible liquids. Cool flames were observed for DMAC at temperatures as much as 44 °C below the autoignition temperature and for DMF at temperatures as much as 171 °C below its autoignition temperature. The DMF cool flame temperatures in the 5-l and 12-l test vessels are approximately equal to the DMF autoignition temperature in a closed 12-l test vessel. Gas samples taken after the cool flame and hot flame tests reveal the presence of high concentrations of diamines and dimethylamino acetonitrile, and small concentrations of many other partial decomposition/oxidation components.     

Evaluation of a video-based measure of driver heart rate

IntroductionInternal driver events such as emotional arousal do not consistently elicit observable behaviors. However, heart rate (HR) offers promise as a surrogate measure for predicting these states in drivers. Imaging photoplethysmography (IPPG) can measure HR from face video recorded in static, indoor settings, but has yet to be examined in an in-vehicle driving environment.MethodsParticipants (N = 10) completed an on-road driving task whilst wearing a commercial, chest-strap style heart rate monitor (“baseline”). IPPG was applied to driver face video to estimate HR and the two measures of HR were compared.ResultsFor 4 of 10 participants, IPPG produced a valid HR signal (± 5 BPM of baseline) between 48 and 75% of trip duration. For the remaining participants, IPPG accuracy was poor (< 20%).ConclusionsIn-vehicle IPPG is achievable, but significant challenges remain.Practical applicationsThe relationship between IPPG accuracy and various confounding factors was quantified for future refinement.