Trauma resuscitation is a complex situation, and most organisations have multi‐professional trauma teams. Non‐technical skills are challenged during trauma resuscitation, and they play an important ...role in the prevention of critical incidents. Simulation‐based training of these is recommended. Our research question was: Does simulation‐based trauma team training of non‐technical skills have effect on reaction, learning, behaviour or patient outcome?
The authors searched PubMed, EMBASE and the Cochrane Library and found 13 studies eligible for analysis. We described and compared the educational interventions and the evaluations of effect according to the four Kirkpatrick levels: reaction, learning (knowledge, skills, attitudes), behaviour (in a clinical setting) and patient outcome.
No studies were randomised, controlled and blinded, resulting in a moderate to high risk of bias. The multi‐professional trauma teams had positive reactions to simulation‐based training of non‐technical skills. Knowledge and skills improved in all studies evaluating the effect on learning. Three studies found improvements in team performance (behaviour) in the clinical setting. One of these found difficulties in maintaining these skills. Two studies evaluated on patient outcome, of which none showed improvements in mortality, complication rate or duration of hospitalisation.
A significant effect on learning was found after simulation‐based training of the multi‐professional trauma team in non‐technical skills. Three studies demonstrated significantly increased clinical team performance. No effect on patient outcome was found. All studies had a moderate to high risk of bias. More comprehensive randomised studies are needed to evaluate the effect on patient outcome.
Hydrogen has a very diverse chemistry and reacts with most other elements to form compounds, which have fascinating structures, compositions and properties. Complex metal hydrides are a rapidly ...expanding class of materials, approaching multi-functionality, in particular within the energy storage field. This review illustrates that complex metal hydrides may store hydrogen in the solid state, act as novel battery materials, both as electrolytes and electrode materials, or store solar heat in a more efficient manner as compared to traditional heat storage materials. Furthermore, it is highlighted how complex metal hydrides may act in an integrated setup with a fuel cell. This review focuses on the unique properties of light element complex metal hydrides mainly based on boron, nitrogen and aluminum, e.g., metal borohydrides and metal alanates. Our hope is that this review can provide new inspiration to solve the great challenge of our time: efficient conversion and large-scale storage of renewable energy.
Globally, the accelerating use of renewable energy sources, enabled by increased efficiencies and reduced costs, and driven by the need to mitigate the effects of climate change, has significantly ...increased research in the areas of renewable energy production, storage, distribution and end-use. Central to this discussion is the use of hydrogen, as a clean, efficient energy vector for energy storage. This review, by experts of Task 32, “Hydrogen-based Energy Storage” of the International Energy Agency, Hydrogen TCP, reports on the development over the last 6 years of hydrogen storage materials, methods and techniques, including electrochemical and thermal storage systems. An overview is given on the background to the various methods, the current state of development and the future prospects. The following areas are covered; porous materials, liquid hydrogen carriers, complex hydrides, intermetallic hydrides, electrochemical storage of energy, thermal energy storage, hydrogen energy systems and an outlook is presented for future prospects and research on hydrogen-based energy storage.
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•A comprehensive review of materials, techniques and methods for hydrogen storage.•International Energy Agency, Task 32 “Hydrogen-based Energy Storage”.•Hydrogen storage in porous materials, metal and complex hydrides.•Applications of metal hydrides for MH compression, thermal and electrochemical storage.•Hydrogen energy systems using metal hydrides.
•Metal borohydrides are a diverse group of materials with many different properties.•Borohydrides’ high hydrogen content make them interesting for hydrogen storage.•Neutral ligands can expand the ...structurally diverse metal and bimetallic borohydrides.•Metal borohydrides are of interest as electrolytes in all solid-state batteries.•Introduction of neutral ligands and nanoparticles can improve dynamics.
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The chemistry of metal borohydrides and their derivatives has expanded signficantly during the past decade involving new compositions, structures, and the diversity of associated properties. Here we provide an overview of interesting results mainly from the past few years, discussed relative to previously published results. A range of new synthesis strategies has been developed to obtain pure samples, which has allowed very detailed structural, physical, and chemical investigations. A short overview of mono- and dimetallic borohydrides is provided, including a description of the complete series of rare-earth metal borohydrides and the recently discovered ammonium metal borohydrides, where the latter has attracted interest due to an extreme hydrogen content. Metal borohydrides appear to be the most promising class of materials to achieve high cationic conductivity of divalent metals, and particularly derivatives of metal borohydrides with neutral molecules show promise as future electrolytes for new types of solid-state batteries. Furthermore, metal borohydrides display a wide range of other properties, including optical, magnetic, semi conduction and possibly superconducting properties, and are also used as a new approach for carbon capture and conversion. The aim of the present review is to highlight new trends in properties and provide an outlook with possible future applications. Here, we focus on the more recently discovered materials.
Synthesis, crystal structures, and thermal and magnetic properties of the complete series of halide-free rare-earth (RE) metal borohydrides are presented. A new synthesis method provides high yield ...and high purity products. Fifteen new metal borohydride structures are reported. The trends in crystal structures, thermal behavior, and magnetic properties for the entire series of RE(BH4) x are compared and discussed. The RE(BH4) x possess a very rich crystal chemistry, dependent on the oxidation state and the ionic size of the rare-earth ion. Due to the lanthanide contraction, there is a significant decrease in the volume of the RE3+-ion with increasing atomic number, which correlates linearly with the unit cell volume of the α- and β-RE(BH4)3 polymorphs and the solvated complexes α-RE(BH4)3·S(CH3)2. The thermal analysis reveals a one-step decomposition pathway in the temperature range from 247 to 277 °C for all RE(BH4)3 except Lu(BH4)3, which follows a three-step decomposition pathway. In contrast, the RE(BH4)2 decompose at higher temperatures in the range 306 to 390 °C due to lower charge density on the rare-earth ion. The RE(BH4)3 show increasing stability with increasing Pauling electronegativity, which contradicts other main group and transition metal borohydrides. The majority of the compounds follow Curie–Weiss paramagnetic behavior down to 3 K with weak antiferromagnetic interactions and magnetic moments in accord with those of isolated 4f ions. Some of the RE(BH4) x display varying degrees of temperature-dependent magnetic moments due to low-lying excited stated induced by crystal field effects. Additionally, a weak antiferromagnetic ordering is observed in Gd(BH4)3, indicating superexchange through a borohydride group.
From Metal Hydrides to Metal Borohydrides Richter, Bo; Grinderslev, Jakob B; Møller, Kasper T ...
Inorganic chemistry,
09/2018, Volume:
57, Issue:
17
Journal Article
Peer reviewed
Commencing from metal hydrides, versatile synthesis, purification, and desolvation approaches are presented for a wide range of metal borohydrides and their solvates. An optimized and generalized ...synthesis method is provided for 11 different metal borohydrides, M(BH4) n , (M = Li, Na, Mg, Ca, Sr, Ba, Y, Nd, Sm, Gd, Yb), providing controlled access to more than 15 different polymorphs and in excess of 20 metal borohydride solvate complexes. Commercially unavailable metal hydrides (MH n , M = Sr, Ba, Y, Nd, Sm, Gd, Yb) are synthesized utilizing high pressure hydrogenation. For synthesis of metal borohydrides, all hydrides are mechanochemically activated prior to reaction with dimethylsulfide borane. A purification process is devised, alongside a complementary desolvation process for solvate complexes, yielding high purity products. An array of polymorphically pure metal borohydrides are synthesized in this manner, supporting the general applicability of this method. Additionally, new metal borohydrides, α-, α′- β-, γ-Yb(BH4)2, α-Nd(BH4)3 and new solvates Sr(BH4)2·1THF, Sm(BH4)2·1THF, Yb(BH4)2·xTHF, x = 1 or 2, Nd(BH4)3·1Me2S, Nd(BH4)3·1.5THF, Sm(BH4)3·1.5THF and Yb(BH4)3·xMe2S (“x” = unspecified), are presented here. Synthesis conditions are optimized individually for each metal, providing insight into reactivity and mechanistic concerns. The reaction follows a nucleophilic addition/hydride-transfer mechanism. Therefore, the reaction is most efficient for ionic and polar-covalent metal hydrides. The presented synthetic approaches are widely applicable, as demonstrated by permitting facile access to a large number of materials and by performing a scale-up synthesis of LiBH4.
The effect of adding both Al2O3 and ZrO2 to limestone (CaCO3) to enhance the cyclic stability and reaction kinetics of endothermic CO2 desorption and exothermic CO2 absorption is investigated. The ...formation of CaZrO3 and Ca-Al-O compounds, e.g. CA5Al6O14, is evident, which enables a substantial >80% capacity retention over 50 calcination/carbonation cycles. The additives enable fast reaction kinetics where an 80% energy storage capacity is reached within 20–30 min, which is attributed to the synergetic effect of having both Ca-Zr-O and Ca-Al-O ternary additives present. The inert nature of the formed compounds prevents sintering of the particles, whilst allowing ion migration throughout the crystal structures, catalysing the carbonation reaction.
•The cyclic stability of CaCO3 is enhanced by ZrO2 and Al2O3 additives.•An energy storage capacity retention of 80% is achieved after 50 cycles.•Reaction kinetics are fast compared to the individual binary systems.•An increased specific surface area is obtained in the ternary system.
We present a hybrid ray tracing system, where the work is divided between the CPU cores and the GPU in an integrated chip, and communication occurs via shared memory. Rays are organized in large ...packets that can be distributed among the two units as needed. Testing visibility between rays and the scene is mostly performed using an optimized kernel on the GPU, but the CPU can help as necessary. The CPU cores typically handle most or all shading, which makes it easy to support complex appearances. For efficiency, the CPU cores shade whole batches of rays by sorting them on material and shading each material using a vectorized kernel. In addition, we introduce a method to support light paths with arbitrary recursion, such as multiple recursive Whitted‐style ray tracing and adaptive sampling where the result of a ray is examined before sending the next, while still batching up rays for the benefit of GPU‐accelerated traversal and vectorized shading. This allows our system to achieve high rendering performance while maintaining the flexibility to accommodate different rendering algorithms.
We present a hybrid ray tracing system, where the work is divided between the CPU cores and the GPU in an integrated chip, and communication occurs via shared memory. Rays are organized in large packets that can be distributed among the two units as needed. Testing visibility between rays and the scene is mostly performed using an optimized kernel on the GPU, but the CPU can help as necessary. The CPU cores typically handle most or all shading, which makes it easy to support complex appearances. For efficiency, the CPU cores shade whole batches of rays by sorting them on material and shading each material using a vectorized kernel.
Metal borohydrides are a fascinating and continuously expanding class of materials, showing promising applications within many different fields of research. This study presents 17 derivatives of the ...hydrogen-rich ammonium borohydride, NH4BH4, which all exhibit high gravimetric hydrogen densities (>9.2 wt % of H2). A detailed insight into the crystal structures combining X-ray diffraction and density functional theory calculations exposes an intriguing structural variety ranging from three-dimensional (3D) frameworks, 2D-layered, and 1D-chainlike structures to structures built from isolated complex anions, in all cases containing NH4 + countercations. Dihydrogen interactions between complex NH4 + and BH4 – ions contribute to the structural diversity and flexibility, while inducing an inherent instability facilitating hydrogen release. The thermal stability of the ammonium metal borohydrides, as a function of a range of structural properties, is analyzed in detail. The Pauling electronegativity of the metal, the structural dimensionality, the dihydrogen bond length, the relative amount of NH4 + to BH4 –, and the nearest coordination sphere of NH4 + are among the most important factors. Hydrogen release usually occurs in three steps, involving new intermediate compounds, observed as crystalline, polymeric, and amorphous materials. This research provides new opportunities for the design and tailoring of novel functional materials with interesting properties.
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