Hot Surface Ignition of Liquid Fuels Under Ventilation.

Mine equipment fires remain as one of the most concerning safety issues in the mining industry, and most equipment fires were caused by hot surface ignitions. Detailed experimental investigations were conducted at the NIOSH Pittsburgh Mining Research Division on hot surface ignition of liquid fuels under ventilation in a mining environment. Three types of metal surface materials (stainless steel, cast iron, carbon steel), three types of liquids (diesel fuel, hydraulic fluid, engine oil), four air ventilation speeds (0, 0.5, 1.5, 3 m/s) were used to study the hot surface ignition probability under these conditions. Visual observation and thermocouples attached on the metal surface were used to indicate the hot surface ignition from the measured temperatures. Results show that the type of metal has a noticeable effect on the hot surface ignition, while ventilation speed has a mixed influence on ignition. Different types of liquid fuels also show different ranges of ignition temperatures. Results from this work can be used to help understand equipment mine fires and develop mitigation strategies.

Estimation of the critical external heat leading to the failure of lithium-ion batteries.

A detailed experimental investigation on the critical external heat leading to the failure of lithium-ion (Li-ion) batteries was conducted using an Accelerating Rate Calorimeter (ARC) at the National Institute for Occupational Safety and Health (NIOSH). Several types of commercial Li-ion batteries were selected for the study, including an iron phosphate Li-ion battery (LFP), a lithium-titanate battery (LTO), and a lithium-nickel-manganese-cobalt-oxide battery (NMC). Each battery was placed in a specially designed sealed steel canister and heated in the ARC. Battery voltage throughout the test was monitored and used to indicate the time to a battery failure. Three thermocouples, one attached to the battery surface, one measuring air temperature inside the canister, and one attached to the canister's internal surface, were used to record temperature changes during the heating tests. Different thermal behaviors were observed for the various battery types. An analytical model was developed to estimate the total external heat received by the battery using the measured temperatures. Experimental data ranked the batteries tested in terms of the heat to failure as: LFP 26650 (11 kJ) > LFP 18650 (4.3 kJ) > NMC 18650 MH1 (3.6 kJ) ≈ LTO 18650 (3.6 kJ) > NMC 18650 HG2 (3 kJ). Total heat normalized to the battery nominal energy capacity was also calculated and ranked as: LTO 18650 ≈ LFP 26650 ≈ LFP 18650 > NMC 18650 MH1 ≈ NMC 18650 HG2. The test and analysis method developed can be extended to other types of batteries with a cylindrical shape. Results from this work provide insights to the thermal safety of Li-ion batteries and can help enhance battery thermal design and management.

The Healthcare Travelling Roadshow: a qualitative study of a rural community engagement initiative in Canada.

INTRODUCTION: Youth from rural communities face significant challenges in the pursuit of healthcare training. Healthcare trainees with a rural background are more likely than those without to practice rurally as healthcare professionals. The Healthcare Travelling Roadshow (HCTRS) is an initiative in Canada that provides rural youth with exposure to healthcare careers, while providing healthcare students with exposure to rural opportunities, and an interprofessional education experience. To the authors' knowledge, this is the first description of an initiative for rural university-high school healthcare career outreach that involves near-peer teaching, highly interactive sessions, and an interprofessional focus. METHODS: Ten HCTRSs took place throughout northern rural and remote British Columbia between 2010 and 2017. Questionnaires were delivered to youth in a pilot research project in 2010. Healthcare students and community members completed questionnaires for ongoing program evaluation from 2010 to 2017. Quantitative elements were graded on a five-point Likert scale. Qualitative elements were analyzed thematically. RESULTS: Participants indicated that the program was very successful (4.71, 95% confidence interval (CI) 4.63-4.79), would likely encourage healthcare students to consider rural practice (4.12, 95%CI 3.98-4.26), and that it inspired local youth to consider careers in health care much or very much (4.45, 95%CI 4.35-4.55). Qualitative analysis led to description of four themes: (1) sincerity and interactivity sparking enthusiasm, (2) learning through rural exposure and community engagement, (3) healthcare student personal growth and (4) interprofessional collaboration and development. Open-ended feedback identified successes outside of the primary goals and illustrated how this program could act in a multi-faceted way to promote healthcare recruitment and retention. Constructive comments emphasized the importance of taking a balanced approach to planning the HCTRS, ensuring the goals of the HCTRS are best met, while meeting the needs of the host communities as much as possible. CONCLUSIONS: The HCTRS is an interdisciplinary experience that successfully engages rural youth, healthcare students, and community stakeholders. Participants consistently indicated that it encouraged rural youth towards healthcare careers and healthcare students towards rural practice. Success of the program requires meaningful engagement with multiple academic and community stakeholders.