Inherent work suit buoyancy distribution:effects on lifejacket self-righting performance

Introduction: Accidental immersion in cold water is an occupational risk. Work suits and life jackets (LJ) should work effectively in combination to keep the airway clear of the water (freeboard) and enable self-righting. We hypothesized that inherent buoyancy, in the suit or LJ, would be beneficial for enabling freeboard, but its distribution may influence LJ self-righting. Methods: Six participants consented to complete nine immersions. Suits and LJ tested were: flotation suit (FLOAT; 85 N inherent buoyancy); oilskins 1 (OS-1) and 2 (OS-2), both with no inherent buoyancy; LJs (inherent buoyancy/buoyancy after inflation/total buoyancy), LJ-1 50/150/200 N, LJ-2 0/290/290 N, LJ-3 80/190/270 N. Once dressed, the subject entered an immersion pool where uninflated freeboard, self-righting performance, and inflated freeboard were measured. Data were compared using Friedman’s test to the 0.05 alpha level. Results: All suits and LJs enabled uninflated and inflated freeboard, but differences were seen between the suits and LJs. Self-righting was achieved on 43 of 54 occasions, irrespective of suit or LJ. On all occasions that self-righting was not achieved, this occurred in an LJ that included inherent buoyancy (11/54 occasions). Of these 11 failures, 8 occurred (73% of occasions) when the FLOAT suit was being worn. Discussion: LJs that included inherent buoyancy, that are certified as effective on their own, worked less effectively from the perspective of self-righting in combination with a work suit that also included inherent buoyancy. Equipment that is approved for use in the workplace should be tested in combination to ensure adequate performance in an emergency scenario

“Float First:” Trapped Air Between Clothing Layers Significantly Improves Buoyancy on Water After Immersion

Approximately 450,000 people drown annually worldwide. The capacity of immersed adults and children to float in clothing is less well understood, but it is possible that air trapped between clothing layers increases buoyancy. Study 1 (n = 24) quantified this buoyancy and the consequence of any buoyancy by measurement of airway freeboard (mouth to water level distance). Study 2 examined the capability of children (n = 29) to float with freeboard used as the outcome measure and is expressed as a percentage of occasions that freeboard was achieved. Buoyancy (Newtons; N) was provided for winter clothing as 105 [+ 12], Autumn/Spring 87 [+ 13], Summer 68 [+ 11]N. Average freeboard was 63 (+ 2) % for winter clothing, 62 (+ 2) % for autumn/spring clothing, 66[+ 2] % for summer clothing, and 15[+ 1] % for the control condition. Children were more buoyant, 95 [+ 17] % freeboard), irrespective of gender, than adults. “Float first” should be advocated

“Float First:” Trapped Air Between Clothing Layers Significantly Improves Buoyancy on Water After Immersion

Approximately 450,000 people drown annually worldwide. The capacity of immersed adults and children to float in clothing is less well understood, but it is possible that air trapped between clothing layers increases buoyancy. Study 1 (n = 24) quantified this buoyancy and the consequence of any buoyancy by measurement of airway freeboard (mouth to water level distance). Study 2 examined the capability of children (n = 29) to float with freeboard used as the outcome measure and is expressed as a percentage of occasions that freeboard was achieved. Buoyancy (Newtons; N) was provided for winter clothing as 105 [+ 12], Autumn/Spring 87 [+ 13], Summer 68 [+ 11]N. Average freeboard was 63 (+ 2) % for winter clothing, 62 (+ 2) % for autumn/spring clothing, 66[+ 2] % for summer clothing, and 15[+ 1] % for the control condition. Children were more buoyant, 95 [+ 17] % freeboard), irrespective of gender, than adults. “Float first” should be advocated

The effect of organoclay addition on the properties of an acrylate based, thermally activated shape memory polymer

Shape Memory Polymers (SMPs) exhibit the intriguing ability to change back from an intermediate, deformed shape back to their original, permanent shape. In this contribution a systematic series of t-butylacrylate-co-poly(ethyleneglycol) dimethacrylate (tBA-co-PEGDMA) polymers have been synthesised and characterised prior to incorporation of organoclay. Increasing the poly(ethyleneglycol) dimethacrylate (PEGDMA) content in increments of 10% increased the storage modulus from 2005 to 2250 MPa, reduced the glass transition temperature from + 41 to − 26 °C and reduced the intensity of the associated tan δ peak. The tBA-co-PEGDMA crosslinked networks displayed useful shape memory properties up to PEGDMA contents of 40%. Above this PEGDMA percentage the materials were prone to fracture and too brittle for a realistic assessment of their shape memory capability. The system containing 90% t-butylacrylate (tBA) and 10% PEGDMA was selected as the host matrix to investigate how the incorporation of 1 to 5 mass% of a benzyl tallow dimethylammonium-exchanged bentonite (BTDB) influenced the shape memory properties. X-ray diffraction data confirmed that BTDB formed a microcomposite in the selected matrix and exerted no influence on the storage modulus, rubbery modulus, glass transition temperature, Tg, or the shape or intensity of the tan δ peak of the host matrix. Therefore, it was anticipated that the presence of BTDB would have no effect, positive or negative, nor on the shape memory properties of the host matrix. However, it was found that the incorporation of clay, especially at the 1 mass% level, significantly accelerated the speed, compared with the clay-free SMP, at which the microcomposite returned to the original, permanent shape. This accelerated return to the permanent shape was also observed when the microcomposite was coated onto a 100 μm PET film

Cooling athletes with a spinal cord injury

Cooling strategies that help prevent a reduction in exercise capacity whilst exercising in the heat have received considerable research interest over the past 3 decades, especially in the lead up to a relatively hot Olympic and Paralympic Games. Progressing into the next Olympic/Paralympic cycle, the host, Rio de Janeiro, could again present an environmental challenge for competing athletes. Despite the interest and vast array of research into cooling strategies for the able-bodied athlete, less is known regarding the application of these cooling strategies in the thermoregulatory impaired spinal cord injured (SCI) athletic population. Individuals with a spinal cord injury (SCI) have a reduced afferent input to the thermoregulatory centre and a loss of both sweating capacity and vasomotor control below the level of the spinal cord lesion. The magnitude of this thermoregulatory impairment is proportional to the level of the lesion. For instance, individuals with high-level lesions (tetraplegia) are at a greater risk of heat illness than individuals with lower-level lesions (paraplegia) at a given exercise intensity. Therefore, cooling strategies may be highly beneficial in this population group, even in moderate ambient conditions (~21 °C). This review was undertaken to examine the scientific literature that addresses the application of cooling strategies in individuals with an SCI. Each method is discussed in regards to the practical issues associated with the method and the potential underlying mechanism. For instance, site-specific cooling would be more suitable for an athlete with an SCI than whole body water immersion, due to the practical difficulties of administering this method in this population group. From the studies reviewed, wearing an ice vest during intermittent sprint exercise has been shown to decrease thermal strain and improve performance. These garments have also been shown to be effective during exercise in the able-bodied. Drawing on additional findings from the able-bodied literature, the combination of methods used prior to and during exercise and/or during rest periods/half-time may increase the effectiveness of a strategy. However, due to the paucity of research involving athletes with an SCI, it is difficult to establish an optimal cooling strategy. Future studies are needed to ensure that research outcomes can be translated into meaningful performance enhancements by investigating cooling strategies under the constraints of actual competition. Cooling strategies that meet the demands of intermittent wheelchair sports need to be identified, with particular attention to the logistics of the sport

Physiological Cost and Thermal Envelope: a Novel Approach to Cycle Garment Evaluation during a Representative Protocol Original Investigation Running Head: Evaluating cycle clothing during exercise

and was independent of clothing assembly. In contrast, an 'envelope' was evident for mean body temperature, resulting from differences in mean skin temperature between the LOW and HI conditions. The elevated mean body temperature in HI was associated with increased physiological 'cost', in the form of increased sweat production and heart rate. Conclusion: Physiological 'cost' provides a better index of clothing performance than deep body temperature in the 'thermoregulatory zone', as a consequence sports clothing should attempt to optimise the balance between comfort and reduced 'physiological cost.&apos

Association between air temperature and unintentional drowning risk in the United Kingdom 2012-2019: a nationwide case crossover study:Air temperature and drowning

Objective: Drowning is a leading cause of death. The World Health Organization (WHO) and United Nations (UN) emphasise the need for population-level data-driven approaches to examine risk factors to improve water safety policies. Weather conditions, have the potential to influence drowning risk behaviours as people are more likely to spend time around water and/or undertake risky activities in aquatic spaces as a behavioural thermoregulatory response (e.g., seeking coolth). Methods: A case-crossover approach assessed associations between changes in daily maximum air temperature (data from the nearest weather station to each drowning event) and unintentional drowning risk using anonymous data from the validated UK Water Incident Database 2012-2019 (1,945 unintentional deaths, 82% male). Control days were selected using a unidirectional time-stratified approach, whereby seven and 14 days before the hazard day were used as the controls. Results: Mean maximum air temperature on case and control days was 15.36oC and 14.80oC, respectively. A 1oC increase in air temperature was associated with a 7.2% increase in unintentional drowning risk. This relationship existed for males only. Drowning risk was elevated on days where air temperature reached 15-19.9oC (Odds Ratio; OR: 1.75), 20-24.9oC (OR: 1.87), and ≥25oC (OR: 4.67), compared with days &lt;10oC. The greatest elevations in risk appeared to be amongst males and when alcohol intoxication was suspected. Precipitation showed no significant association with unintentional drowning risk.Conclusions: Identifying such relationships highlights the value of considering weather conditions when evaluating environmental risk factors for drowning, and may inform water safety policy and allocating resources to prevention and rescue.<br/