A Review of Recent Advances on the Effects of Microstructural Refinement and Nano-Catalytic Additives on the Hydrogen Storage Properties of Metal and Complex Hydrides

The recent advances on the effects of microstructural refinement and various nano-catalytic additives on the hydrogen storage properties of metal and complex hydrides obtained in the last few years in the allied laboratories at the University of Waterloo (Canada) and Military University of Technology (Warsaw, Poland) are critically reviewed in this paper. The research results indicate that microstructural refinement (particle and grain size) induced by ball milling influences quite modestly the hydrogen storage properties of simple metal and complex metal hydrides. On the other hand, the addition of nanometric elemental metals acting as potent catalysts and/or metal halide catalytic precursors brings about profound improvements in the hydrogen absorption/desorption kinetics for simple metal and complex metal hydrides alike. In general, catalytic precursors react with the hydride matrix forming a metal salt and free nanometric or amorphous elemental metals/intermetallics which, in turn, act catalytically. However, these catalysts change only kinetic properties i.e. the hydrogen absorption/desorption rate but they do not change thermodynamics (e.g., enthalpy change of hydrogen sorption reactions). It is shown that a complex metal hydride, LiAlH4, after high energy ball milling with a nanometric Ni metal catalyst and/or MnCl2 catalytic precursor, is able to desorb relatively large quantities of hydrogen at RT, 40 and 80 °C. This kind of behavior is very encouraging for the future development of solid state hydrogen systems

The accuracy of adult limb radiograph interpretation by emergency nurse practitioners: A prospective comparative study

Background: One of the extensions to practice for the emergency nurse practitioner role is to appropriately order and interpret radiographs in the emergency department. Objective: The aim of the study was to compare the accuracy in interpreting isolated adult limb radiographs between emergency nurse practitioners and emergency physicians. Design: A prospective comparative study was undertaken. Setting: Emergency department in a large metropolitan hospital. Participants: 200 adult patients with isolated limb injuries were consented. Methods: Six emergency nurse practitioners and ten emergency physicians participated. One emergency physician and emergency nurse practitioner independently clinically assessed each patient, determined the need for radiograph and separately recorded their interpretation of the radiograph as either definite fracture, no fracture or possible fracture. A single consultant radiologist reviewed each radiograph and their interpretation was seen as the gold standard. The sensitivity and specificity of emergency physicians and emergency nurse practitioners were calculated. To measure the level of agreement between the two-clinician groups, the weighted Kappa statistic was used. Results: The sensitivity for the emergency nurse practitioners was 91% and 88% for the emergency physicians. The specificity for the emergency nurse practitioners was 85% and for the emergency physicians 91%. The weighted Kappa on the presence of a fracture between the emergency nurse practitioners and emergency physicians was 0.83. Conclusions: This study validates the clinical and diagnostic skills of emergency nurse practitioners assessed in the interpretation of isolated adult limb injury radiographs.</p

Trauma resuscitation errors and computer-assisted decision support

Hypothesis This project tested the hypothesis that computer-aided decision support during the first 30 minutes of trauma resuscitation reduces management errors. Design Ours was a prospective, open, randomized, controlled interventional study that evaluated the effect of real-time, computer-prompted, evidence-based decision and action algorithms on error occurrence during initial resuscitation between January 24, 2006, and February 25, 2008. Setting A level I adult trauma center. Patients Severely injured adults. Main Outcome Measures The primary outcome variable was the error rate per patient treated as demonstrated by deviation from trauma care algorithms. Computer-assisted video audit was used to assess adherence to the algorithms. Results A total of 1171 patients were recruited into 3 groups: 300 into a baseline control group, 436 into a concurrent control group, and 435 into the study group. There was a reduction in error rate per patient from the baseline control group to the study group (2.53 to 2.13, P = .004) and from the control group to the study group (2.30 to 2.13, P = .04). The difference in error rate per patient from the baseline control group to the concurrent control group was not statistically different (2.53 to 2.30, P = .21). A critical decision was required every 72 seconds, and error-free resuscitations were increased from 16.0% to 21.8% (P = .049) during the first 30 minutes of resuscitation. Morbidity from shock management (P = .03), blood use (P < .001), and aspiration pneumonia (P = .046) were decreased. Conclusions Computer-aided, real-time decision support resulted in improved protocol compliance and reduced errors and morbidity

Mg2Si nanoparticle synthesis for high pressure hydrogenation

The Mg-Si-H system is economically favorable as a hydrogen storage medium for renewable energy systems while moving toward sustainable energy production. Hydrogen desorption from MgH2 in the presence of Si is achievable, forming magnesium silicide (Mg2Si). However, absorbing hydrogen into Mg2Si remains problematic due to severe kinetic limitations. The objective of this study is to reduce these kinetic limitations by synthesizing Mg2Si nanoparticles to limit the migration distance for magnesium atoms from the Mg2Si matrix to produce MgH2 and Si, thus improving the reversibility of the Mg-Si-H system. Mg2Si nanoparticles were synthesized using a reduction reaction undertaken by solid-liquid mechanochemical ball milling. Particle size was controlled by adding a reaction buffer (lithium chloride) to the starting reagents to restrict particle growth during milling. The reaction buffer was removed from the nanoparticles using tetrahydrofuran and small-angle X-ray scattering revealed an average Mg2Si particle size of ~10 nm, the smallest Mg2Si nanoparticles synthesized to date. High-pressure hydrogen measurements were undertaken above thermodynamic equilibrium at a range of temperatures to attempt hydrogen absorption into the Mg2Si nanoparticles. X-ray diffraction results indicate that partial hydrogen absorption took place. Under these absorption conditions bulk Mg2Si cannot absorb hydrogen, demonstrating the kinetic benefit of nanoscopic Mg2Si