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Mixed solid solutions have played an important role in improving the kinetics and performance of hydrogen storage materials, as reported for the Li–Mg–N–H, K–Mg–N–H, and Rb–Mg–N–H systems. Besides, the formation of a homogeneous solid solution, mostly due to partial ionic substitution, is known to be an effective approach to improve the ionic conductivity of a material, which is an important property in electrochemical applications. We have reported a series of solid solutions based on mixed amide-hydride materials of the Group 1 elements, e.g., K(NH2)xH1–x, Rb(NH2)xH1–x, and Cs(NH2)xH1–x, via the exchange of NH2–/H–anions with the change of the lattice cell of the solid solution. Extending the research in this direction, we study the M–N–H solid solution in the MNH2–MH systems (M = K, Rb, Cs, and their combinations), i.e., KNH2–RbH, RbNH2–KH, RbNH2–CsH, and CsNH2–RbH via ex situ/in situ XRD, IR, and 1H 2D solid-state NMR. The results obtained confirm the formation of mixed metal amide-hydride solid solutions associated with an exchange between both anionic (NH2–and H–) and cationic species (K+, Rb+, and Cs+). With this study, we aim to create an accessible library of M–N–H solid solutions for further studies as additives for hydrogen storage materials or ionic conductors.

Justin Trudeau has resigned after more than nine years as Canada's 23rd prime minister, leaving an indelible mark on the country, particularly in the realm of social policy. During his tenure, Trudeau's government made significant strides in areas such as legalizing cannabis, introducing dental care, pharmacare, and government-subsidized child care. Despite facing challenges and criticism, Trudeau's legacy is characterized by his energetic leadership and commitment to progressive social policies. [Extracted from the article]

Cold spraying is currently developing as a high potential technique for the repair of metallic components, particularly for the deposition of heat-and oxidation-sensitive materials. However, for the appropriate application, it is essential to prepare the component surface suitably to ensure optimum prerequisites for the subsequent material deposition by cold spray. Thus, this work proposes a concept for robot-guided pre-machining for repair by cold spray that includes removal of the damaged volume while considering the requirements for subsequent material deposition. In this concept, digital component and damage data define the dimensions and boundary conditions for material removal. This involves designing a parametric pre-machining target geometry for the damaged component by computer-aided design software that can handle variable surface types. The pre-machining target geometry is adapted to the damage characteristics by considering length, width, depth and orientation. To produce the pre-machining target geometry by machining tools, the adjusted component is exported to computer-aided manufacturing software. The applicability of this concept has been successfully demonstrated on digital use cases with exemplary components and damages as well as by practical application with a milling robot in a laboratory environment. The results demonstrate the capability of this concept for preparing damaged components and promise a high potential to ensure the required prerequisites for high-quality component repair by cold spray.

Using 1986 AHA hospital survey data, we analyzed hospital-HMO contract provisions, hospital operating characteristics, and market conditions for a national sample of 801 hospitals with HMO contracts to determine the [...]

Cold spraying has proved as an attractive and rapidly developing solid-state material deposition process that allows for fast formation of high quality, large 3D volume objects. Low risks of undesirable heat effects lead to increased interest in cold spraying based rapid additive manufacturing. However, by continuous powder spraying and high-pressure gas operation, cold spray additive manufacturing in terms of shape building is sensitive to operating parameters and imposes high requirements on the control of process conditions and locally needed kinematics. Every step of the manufacturing process therefore needs to be meticulously conceived and planned, especially the toolpath planning and implementation. This is not only essential to meet basic performance requirements, but also needed for the desired geometric accuracy. To address these needs, this study presents a new implementation method for cold spray additive manufacturing to improve manufacturing accuracy and flexibility. The workflow and principles of the proposed method are explained and strategies are presented for building up various component types, including rotational geometries as well as freestanding parts. The developed algorithms for 3D applications can be well integrated into the cold spray additive manufacturing process for toolpath planning and path parameter determination. Reliable and accurate robot programs were developed to make the process easy to repeat and to follow. Toolpath planning and robot programming are supported and performed by applying virtual cells to simulate the automation process for the real scenario. Path parameter adjustment and kinematic optimization can then be conducted according to the feedback from the simulation result. Applied benchmarking tests prove acceptable shape accuracy and demonstrate that the current method can enhance the capabilities of cold spray additive manufacturing for near-net shape construction. This implies that careful planning and manufacturing strategies should enable overcoming the challenges associated with cold spray additive manufacturing.

Electronic properties and charge transfer processes were studied in an n-Si(n++)/TiO2(ALD) system at an amorphous TiO2/anatase transition by transient surface photovoltage spectroscopy at constant photon flux. The TiO2layers were deposited by atomic layer deposition (ALD) onto highly doped silicon (c-Si(n++)), and the phase composition of the TiO2layers changed with increasing thickness from amorphous to the anatase polymorph as anatase crystallites started to grow at the surface. Depending on phase composition, the band gap of TiO2correlated with the characteristic energy of exponential tails. In most cases, photogenerated electrons were separated toward the back contact. For photogeneration in c-Si(n++), electron back transfer was limited by Auger recombination with holes in the surface space charge region of c-Si(n++), and by electron transfer across the interface, either via exponentially distributed states near the conduction band edge of amorphous TiO2or via distance-dependent recombination with holes trapped in anatase. For photogeneration in TiO2, electron back transfer was limited by trapping in TiO2. Under strong light absorption in amorphous TiO2with anatase crystallites on top, electrons were preferentially separated toward the TiO2surface.

In this work, the hydrogen sorption properties of the LiBH4–Mg2NiH4composite system with the molar ratio 2:2.5 were thoroughly investigated as a function of the applied temperature and hydrogen pressure. To the best of our knowledge, it has been possible to prove experimentally the mutual destabilization between LiBH4and Mg2NiH4. A detailed account of the kinetic and thermodynamic features of the dehydrogenation process is reported here.

A holistic approach is required for the development of materials and systems for hydrogen storage, embracing all the different steps involved in a successful advance of the technology. The several engineering solutions presented in this work try to address the technical challenges in synthesis and application of solid-state hydrogen storage materials, mainly metal hydride based compounds. Moving from the synthesis of samples in lab-scale to the production of industrial sized batches a novel process development is required, including safety approaches (for hazardous powders), and methods to prevent the contamination of sensitive chemicals. The reduction of overall costs has to be addressed as well, considering new sources for raw materials and more cost-efficient catalysts. The properties of the material itself influence the performances of the hydride in a pilot storage tank, but the characteristics of the system itself are crucial to investigate the reaction limiting steps and overcome hindrances. For this, critical experiments using test tanks are needed, learning how to avoid issues as material segregation or temperature gradients, and optimizing the design in the aspects of geometry, hull material, and test station facilities. The following step is a useful integration of the hydrogen storage system into real applications, with other components like fuel cells or hydrogen generators: these challenging scenarios provide insights to design new experiments and allow stimulating demonstrations.

Light metal hydrides are prone to react with oxygen and/or water to produce oxides and/or hydroxides leading to reduction of hydrogen capacities, and deterioration of the hydrogen storage properties. It is therefore critical to address these issues when the materials are to be exposed to air or moisture. In this work, the combination of light metal hydrides, Mg(NH2)2–nLiH with polymethylpentene (TPX™), an air/moisture protective barrier is presented. It was found that the fabricated composites exhibit significant improvement of the metal hydrides stability in air. No oxidation reactions in air can be proven even after air exposure for 90 min. Extending the air-exposure time to 12 h, the reversible hydrogen capacities of these composites are much higher and more stable than they are in the case of the pure metal hydrides. In comparison to the pure metal hydrides, the composites retain the same hydrogen loading capacities and kinetic properties, with respect to the metal hydrides contents. Further, in situsynchrotron radiation powder X-ray radiation diffraction (SR-PXRD) experiments reveal that the thermal decomposition reaction pathways of the 90 min air-exposed composites are the same under air or H2atmosphere. Moreover, morphology analysis confirms that the metal hydrides remain stable in the polymeric matrix and the three-dimensional integrity is retained, even after performing tens of de/re-hydrogenation cycles. The present study shows a promising way to fabricate air-stable metal hydride-polymer composite hydrogen storage materials that can be handled in ambient conditions.

To enhance the dehydrogenation/rehydrogenation kinetic behavior of the LiBH4–MgH2composite system, TiF4is used as an additive. The effect of this additive on the hydride composite system has been studied by means of laboratory and advanced synchrotron techniques. Investigations on the synthesis and mechanism upon hydrogen interaction show that the addition of TiF4to the LiBH4–MgH2composite system during the milling procedure leads to the in situ formation of well-distributed nanosized TiB2particles. These TiB2nanoparticles act as nucleation agents for the formation of MgB2upon dehydrogenation process of the hydride composite system. The effect of TiB2nanoparticles is maintained upon cycling.

Solid-state hydride compounds are a promising option for efficient and safe hydrogen-storage systems. Lithium reactive hydride composite system 2LiBH4+ MgH2/2LiH + MgB2(Li-RHC) has been widely investigated owing to its high theoretical hydrogen-storage capacity and low calculated reaction enthalpy (11.5 wt % H2and 45.9 kJ/mol H2). In this paper, a thorough investigation into the effect of the formation of nano-TiAl alloys on the hydrogen-storage properties of Li-RHC is presented. The additive 3TiCl3·AlCl3is used as the nanoparticle precursor. For the investigated temperatures and hydrogen pressures, the addition of ∼5 wt % 3TiCl3·AlCl3leads to hydrogenation/dehydrogenation times of only 30 min and a reversible hydrogen-storage capacity of 9.5 wt %. The material containing 3TiCl3·AlCl3possesses superior hydrogen-storage properties in terms of rates and a stable hydrogen capacity during several hydrogenation/dehydrogenation cycles. These enhancements are attributed to an in situ nanostructure and a hexagonal AlTi3phase observed by high-resolution transmission electron microscopy. This phase acts in a 2-fold manner, first promoting the nucleation of MgB2upon dehydrogenation and second suppressing the formation of Li2B12H12upon hydrogenation/dehydrogenation cycling.

The crystal structure of a mixed amide-imide phase, RbMgND2ND, has been solved in the orthorhombic space group Pnma(a= 9.55256(31), b= 3.70772(11) and c= 10.08308(32) Å). A new metal amide-hydride solid solution, Rb(NH2)xH(1–x), has been isolated and characterized in the entire compositional range. The profound analogies, as well as the subtle differences, with the crystal chemistry of KMgND2ND and K(NH2)xH1–xare thoroughly discussed. This approach suggests that the comparable performances obtained using K- and Rb-based additives for the Mg(NH2)2-2LiHand 2LiNH2–MgH2hydrogen storage systems are likely to depend on the structural similarities of possible reaction products and intermediates.

In this work, the hydrogen absorption and desorption properties of the system K2[Zn(NH2)4]-8LiH are investigated in detail via in situ synchrotron radiation powder X-ray diffraction (SR-PXD), Fourier transform infrared spectroscopy (FT-IR), and volumetric methods. Upon milling, K2[Zn(NH2)4] and 8LiH react to form 4LiNH2-4LiH-K2ZnH4, and then 4LiNH2-4LiH-K2ZnH4releases H2in multiple steps. The final products of the desorption reaction are KH, LiZn13, and Li2NH. During rehydrogenation, KH reacts with LiZn13under 50 bar of hydrogen producing K3ZnH5. This phase appears to enhance the hydrogenation process which after its formation at ca. 220 °C takes place in only 30 s. The system 4LiNH2-4LiH-K2ZnH4is shown to be reversible under the applied conditions of vacuum at 400 °C for desorption and 50 bar of H2at 300 °C for absorption.

A mixture of 3NaH/AlB2was prepared by ball-milling; its hydriding reaction was studied between 375–425 °C and 25–50 bar hydrogen pressure by means of volumetric titration. The hydriding reaction was characterized by means of in situ synchrotron radiation powder X-ray diffraction and high-pressure differential scanning calorimetry. Hydriding reaction took place at the molten state, and its reaction products were NaBH4and Al. The scanning electron microscopy images of the material revealed that the material morphology changes after hydriding. A maximum hydrogen uptake of 4.7 wt % was registered for the hydriding experiment at 425 °C and 50 bar hydrogen pressure. Dehydriding reaction was studied by means of volumetric titration and differential scanning calorimetry. The dehydriding reaction at 425 °C and 1 bar argon pressure registered a release of 2.4 wt %. The low dehydriding level was attributed to the reduction of the available particle surface upon melting of the material during the hydriding reaction.

Continuously graded materials of Al-based matrix composites reinforced by SiC particles attract increasing attention due to demands for altered thermoelectric and mechanical properties over defined scales. To ensure tailored gradients while avoiding undesirable side reactions, this work focusses on cold spraying as a promising production technique. So far, cold spraying has proved the potential for fabricating aluminum matrix composites with a uniform distribution of reinforcements. The present study explores the direct fabrication of graded composites by applying a constant feed rate of Al powder and gradually increasing feed rates of SiC powder during cold spraying by employing two powder feed lines. The systematic comparison of two SiC powder sizes allows for the identification of common features in composite formation and deducing technical prerequisites for obtaining uniform as well as graded composites. Key issues of microstructural and mechanical investigations concern the attainable hard-phase contents and distributions over the deposit thickness. If a fine hard-phase feedstock powder is used, well-consolidated microstructures with graded SiC distributions are obtained. In case of a coarse hard-phase powder, the layer build-up is less homogeneous. The comparison between the results of the present work and the corresponding literature data reveals similar deposition efficiencies of SiC for co-deposition and the use of pre-mixed powders. However, if cold spraying such blends, the hard-phase contents of the deposits are lower than those of the feedstock powder mix. Furthermore, hard phase contents are lower than for conventional, high-temperature processing techniques. Based on the comparison, the requirements for achieving a wider range of hard phase contents in cold sprayed deposits are elucidated, in particular regarding the feedstock powders and the powder feeder. The acquired understanding can also be transferred to cold spraying of other graded material combinations.

Cold gas spraying (CGS) is presented as an innovative approach to deposit semiconductor particles onto substrates in order to form photoelectrodes for electrochemical applications. Thin layers of TiO2 (P25-20 by Evonik Industries) are deposited onto titanium substrates (TiO2-CGS films) at different temperatures of the gas carrier within the CGS process (300 - 1000 degC). Structural characterization reveals unchanged bulk properties of the TiO2 nanoparticles. Clearly, the short duration time of the CGS process hinders crystalline bulk changes of the TiO2 particles in the hot gas stream. However, surface photovoltage measurements indicate that the CGS process modified defect states at the surface when exposed to different gas temperature. In photoelectrochemical measurements TiO2-CGS films yield seven times higher photocurrents and IPCE values than comparable films prepared by the well-established doctor blade technique. The increased efficiency might be due to an enhanced particle to substrate bonding caused by particles welding to the metallic substrate during the cold gas spray process.

Light metal tetrahydroborates are regarded as promising materials for solid state hydrogen storage. Due to both a high gravimetric hydrogen capacity of 11.5 wt % and an ideal dehydrogenation enthalpy of 32 kJ mol–1H2, Ca(BH4)2is considered to be one of the most interesting compounds in this class of materials. In this work, a comprehensive investigation of the effect of different selected additives (TiF4, NbF5, Ti-isopropoxide, and CaF2) on the reversible hydrogenation reaction of calcium borohydride is presented combining different investigation techniques. The chemical state of the Nb- and Ti-based additives is studied by X-ray absorption spectroscopy (e.g., XANES). Transmission electron microscopy (TEM) coupled with selected area electron diffraction (SAED) and energy-dispersive X-ray spectroscopy (EDX) was used to show the local structure, size, and distribution of the additive/catalyst. 11B{1H} solid state magic angle spinning-nuclear magnetic resonance (MAS NMR) was carried out to detect possible amorphous phases. The formation of TiB2and NbB2nanoparticles was observed after milling or upon sorption reactions of the Nb- and Ti-based Ca(BH4)2doped systems. The formation of transition-metal boride nanoparticles is proposed to support the heterogeneous nucleation of CaB6. The {111}CaB6/{1011}NbB2, {111}CaB6/{1010}NbB2, as well as {111}CaB6/{1011}TiB2plane pairs have the potential to be the matching planes because the d-value mismatch is well below the d-critical mismatch value (6%). Transition-metal boride nanoparticles act as heterogeneous nucleation sites for CaB6, refine the microstructure thus improving the sorption kinetics, and, as a consequence, lead to the reversible formation of Ca(BH4)2.

The Ca(BH4)2–MgH2composite system represents a promising candidate for mobile hydrogen storage due to a 10.5 wt % theoretical hydrogen storage capacity and an estimated equilibrium temperature lower than 160 °C. For this system, the reversibility was achieved without further addition of additives. In this study, the decomposition path of the Ca(BH4)2+ MgH2composite system is investigated in detail by in situ synchrotron radiation powder X-ray diffraction and differential scanning calorimetry combined with thermogravimetry. The sorption properties are analyzed by volumetric measurements. 11B{1H} solid state magic angle spinning–nuclear magnetic resonance was employed for the characterization of the final amorphous or nanocrystalline boron-based decomposition products. This study shows that the intermediate formation of Ca4Mg3H14upon dehydrogenation of the Ca(BH4)2–MgH2composite system is not a necessary step, and its presence can be adjusted modifying the preparation procedure. Moreover, the d-value mismatch calculated for the {111}CaB6/{1011}Mg plane pair is the lowest among the other plane pairs considered in the system. The mismatch in the third direction between CaB6and Mg is also extremely good. These findings propose Mg as a supporter of the heterogeneous nucleation of CaB6during decomposition of the Ca(BH4)2+ MgH2composite system.

Chemical reactions between LiF and MgB2with different molar ratios of 1:1 and 4:1 under hydrogen atmosphere were studied by high-pressure differential scanning calorimetry (HP-DSC) and in situ synchrotron radiation power X-ray diffraction. Hydrogen sorption properties of the composites were evaluated using a Sievert’s type apparatus. After hydrogenation only LiBH4and MgF2are found as the main products. However, DSC characterization showed multistep events related to LiBH4that might be explained by different phases or some intermediates.

A reactive hydride composite (RHC) with initial composition 3CaH2+ 4MgB2+ CaF2was studied by in situ synchrotron radiation powder X-ray diffraction (SR-PXD) and X-ray absorption near edge structure (XANES) at the B K-edge and at the Ca K-edge. The hydrogenation reaction proceeds by an unknown intermediate. No evidence of intermediates was observed during the dehydrogenation reaction. B and Ca K-edge XANES results hint to a closed interaction of CaF2and Ca(BH4)2. The main function of CaF2in the 3CaH2+ 4MgB2+ CaF2RHC is as a dopant for the hydrogenation and dehydrogenation reactions.

The reactive hydride composite of 2LiBH4–MgH2has been melt infiltrated in a resorcinol–furfural (RFF) carbon aerogel scaffold. Dried aerogel of RFF, further pyrolyzed to obtain a carbon aerogel scaffold, is prepared by CO2supercritical drying, where time consumption is significantly lower than the normal procedures of solvent exchange and drying under ambient conditions. On the basis of scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDS) mapping, the complex hydrides are homogeneously dispersed in the nanometer scale both inside the nanopores and over the surface of the RFF carbon aerogel. Synchrotron radiation powder X-ray diffraction (SR–PXD) and Raman results reveal the reaction mechanisms during melt infiltration, de- and rehydrogenation of this system, as well as the differences from the previous studies of the nanoconfined 2LiBH4–MgH2in a resorcinol–formaldehyde (RF) carbon aerogel. Thermogravimetric and hydrogen titration measurements reveal a significant improvement in dehydrogenation kinetics of 2LiBH4–MgH2–RFF as compared with the bulk 2LiBH4–MgH2system. For instance, an approximate single-step dehydrogenation together with almost 100% of the total hydrogen storage capacity is accomplished within 6 h during the first dehydrogenation, while the bulk material performs clearly two-step reaction and requires ∼30 h (at T= 45 °C and p(H2) = 3–4 bar). Moreover, the gravimetric hydrogen storage capacity in the range of 4.2–4.8 wt % (∼10–11.2 wt % H2with respect to the hydride content) is maintained over four dehydrogenation and rehydrogenation cycles.

The combination of Ca(BH4)2and MgH2materials results in a composite with remarkable hydrogen storage properties. However, full reversibility upon the (re)hydrogenation reaction has not yet been achieved. The poor reversibility is shown to be linked to the formation of stable intermediate phases or side products upon decomposition. In this work, we show, for the first time, the clear experimental evidence of CaB12H12among the decomposition products of a Ca(BH4)2+ MgH2composite. A combination of 11B Magic Angle Spinning–Nuclear Magnetic Resonance (11B{1H} MAS NMR), ex situ X-ray diffraction (XRD) and Rietveld analysis are presented. An assessment of the (de)hydrogenation and (re)hydrogenation reactions of Ca(BH4)2+ MgH2composite is reported. The experimental results provided in this work highlight the reasons for the limited reversibility observed in the Ca(BH4)2+ MgH2composite upon (re)hydrogenation.

Characterization with neutrons and synchrotron radiation has yielded essential contributions to the research and development of automotive and aerospace materials, processing methods, and components. This review mainly emphasises developments related to commercial passenger airplanes and light‐duty cars. Improved and partly new materials for the reduction of airframe weight and joining by laser‐beam welding and friction stir welding are ongoing areas of assessment. Chemical reactions, microstructure development, and residual stresses are frequently measured. Polymers and polymer matrix composites often require special experimental techniques. The thrust‐to‐weight ratio of aero‐engines is increasing due to the improved design of components and the use of innovative materials. Investigations on superalloys, γ‐TiAl, and thermal barrier coatings are described in some detail. A discussion of the use of neutron and synchrotron diffraction in automotive applications covers the analysis of surface effects with respect to lubricants and wear, as well as the investigation of microstructure development, deformation, and fatigue behavior of materials, welds and components. Special steels, Al and Mg alloys are discussed and residual stresses in automotive components such as gears or crankshafts are described. Applications of characterization methods on membranes for polymeric membrane fuel cells and on nanocrystalline metal hydrides for hydrogen storage are shown. The degradation of railway tracks after long‐term use is taken as an example for the application of synchrotron methods to transport systems beyond the commercial aircraft and light duty passenger car.

Complex hydrides are very promising candidates for future light‐weight solid state hydrogen storage materials. The present work illustrates detailed characterization of such novel hydride materials on different size scales by the use of synchrotron radiation and neutrons. The comprehensive analysis of such data leads to a deep understanding of the ongoing processes and mechanisms. The reaction pathways during hydrogen desorption and absorption are identified by in situ X‐ray diffraction (XRD). Function and size of additive phases are estimated using X‐ray absorption spectroscopy (XAS) and anomalous small‐angle X‐ray scattering (ASAXS). The structure of the metal hydride matrix is characterized using (ultra) small‐angle neutron scattering (SANS/USANS). The hydrogen distribution in tanks filled with metal hydride material is studied with neutron computerized tomography (NCT). The results obtained by the different analysis methods are summarized in a final structural model. The complementary information obtained by these different methods is essential for the understanding of the various sorption processes in light metal hydrides and hydrogen storage tanks.

Nanoconfined 2LiBH4–MgH2is prepared by direct melt infiltration of bulk 2LiBH4–MgH2into an inert nanoporous resorcinol–formaldehyde carbon aerogel scaffold material. Scanning electron microscopy (SEM) micrographs and energy dispersive X-ray spectroscopy (EDS) mapping reveal homogeneous dispersion of Mg (from MgH2) and B (from LiBH4) inside the carbon aerogel scaffold. Moreover, nanoconfinement of LiBH4in the carbon aerogel scaffold is confirmed by differential scanning calorimetry (DSC). The hydrogen desorption kinetics of the nanoconfined 2LiBH4–MgH2is significantly improved as compared to bulk 2LiBH4–MgH2. For instance, the nanoconfined 2LiBH4–MgH2releases 90% of the total hydrogen storage capacity within 90 min, whereas the bulk material releases only 34% (at T= 425 °C and p(H2) = 3.4 bar). A reversible gravimetric hydrogen storage capacity of 10.8 wt % H2, calculated with respect to the metal hydride content, is preserved over four hydrogen release and uptake cycles.

A composite of Ca(BH4)2−MgF2is proposed as a reversible hydrogen storage system. The dehydrogenation and rehydrogenation reaction mechanisms are investigated by in situtime-resolved synchrotron radiation powder X-ray diffraction (SR-PXD) and Raman spectroscopy. The formation of an intermediate phase (CaF2−xHx) is observed during rehydrogenation. The hydrogen content of 4.3 wt % is obtained within 4 h during the first dehydrogenation at isothermal and isobaric conditions of 330 °C and 0.5 bar H2, respectively. The cycling efficiency is evaluated by three release and uptake cycles together with absorbed hydrogen content in the range 5.1−5.8 wt % after 2.5 h (T= 330 °C and p(H2) = 130 bar). The kinetic properties on the basis of hydrogen absorption are comparable for all cycles. As compared to pure Ca(BH4)2and Ca(BH4)2−MgH2composite, Ca(BH4)2−MgF2composite reveals the kinetic destabilization and the reproducibility of hydrogen storage capacities during cycling, respectively.

Light metal borohydrides are considered as promising materials for solid state hydrogen storage. Because of the high hydrogen content of 11.5 wt % and the rather low dehydrogenation enthalpy of 32 kJ mol−1H2, Ca(BH4)2is considered to be one of the most interesting compounds in this class of materials. In the present work, the effect of selected TM-fluoride (TM = transition metal) additives on the reversible formation of Ca(BH4)2was investigated by means of thermovolumetric, calorimetric, Fourier transform infrared spectroscopy, and ex situ, and in situ synchrotron radiation powder X-ray diffraction (SR-PXD) measurements. Furthermore, selected desorbed samples were analyzed by 11B{1H} solid state magic angle spinning nuclear magnetic resonance (MAS NMR). Under the conditions used in this study (145 bar H2pressure and 350 °C), TiF4and NbF5were the only additives causing partial reversibility. In these two cases, 11B{1H} MAS NMR analyses detected CaB6and likely CaB12H12in the dehydrogenation products. Elemental boron was found in the decomposition products of Ca(BH4)2samples with VF4, TiF3, and VF3. The results indicate an important role of CaB6for the reversible formation of Ca(BH4)2.

The hydrogenation of the CaH2MgB2composite and the dehydrogenation of the resulting products are investigated in detail by in situ time-resolved synchrotron radiation powder X-ray diffraction, high-pressure differential scanning calorimetry, infrared, and thermovolumetric measurements. It is demonstrated that a Ca(BH4)2MgH2composite is formed by hydrogenating a CaH2MgB2composite, at 350 °C and 140 bar of hydrogen. Two phases of Ca(BH4)2were characterized:  - and -Ca(BH4)2. -Ca(BH4)2transforms to -Ca(BH4)2at about 130 °C. Under the conditions used in the present study, -Ca(BH4)2decomposes first to CaH2, Ca3Mg4H14, Mg, B (or MgB2depending on experimental conditions), and hydrogen at 360 °C, before complete decomposition to CaH2, Mg, B (or MgB2), and hydrogen at 400 °C. During hydrogenation under 140 bar of hydrogen, -Ca(BH4)2is formed at 250 °C, and -Ca(BH4)2is formed when the sample is cooled to less than 130 °C. Ti isopropoxide improves the kinetics of the reactions, during both hydrogenation and dehydrogenation. The dehydrogenation temperature decreases to 250 °C, with 1 wt % of this additive, and hydrogenation starts already at 200 °C. We propose that the improved kinetics of the above reactions with MgB2(compared to pure boron) can be explained by the different boron bonding within the crystal structure of MgB2and pure boron.

As a result of the devolution of labor market policy, new governance arrangements have arisen in the past decade in both Canada and the United Kingdom. These emerging relations are analyzed with respect to the degree to which they have facilitated the democratic engagement of stakeholders, citizens and legislators. Post devolution the Canadian federal system demonstrates decreased democratic engagement, while in the United Kingdom it has increased substantially. This is attributable to the competitive intergovernmental relationship in Canada, and the unwillingness on the part of federal and provincial politicians and officials to collectively engage with stakeholders and citizens. In contrast, intergovernmental relations in the early days of United Kingdom devolution are cooperative, due to the presence of civil service and political party accommodation processes not found in Canada. The European Union also contributes to democratic engagement in the United Kingdom, providing an opportunity for social partners and civil society to participate in policy making.

Nanocrystalline intermetallic Mg2Ni is successfully produced on a batch production scale from elemental powder blends by mechanical alloying using a high-energy rotor ball mill (Simoloyer). Different ball-to-powder mass ratios are used in order to provide results for scaling to industrial production. Transformation of elemental Mg-Ni powders into the Mg2Ni intermetallic is observed by x-ray diffraction. Particle morphology during milling is observed by scanning electron microscopy. A relatively low Fe contamination is estimated by energy dispersive spectrometry.

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A common finding of past research is that people who stutter are stereotyped as being more guarded, nervous, self-conscious, tense, sensitive, hesitant, introverted, and insecure than nonstutterers. Using an innovative survey method, two questions studied were (1) whether individuals who have on going contact with the same stutterer share the negative stereotype identified by past research, and (2) whether there are differences in perceptions of speech fluency between stutterers and their listeners. Responses of 114 friends and colleagues of stutterers found those who had on-going contact with at least one stutterer have less stereotypical attitudes than the general population, and significant differences in perceptions about normalcy of speech were noted for people who stutter and those with whom they interact.

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Hydrogen produced from solar energy has the potential to replace petroleum in the future. To this respect, there is a need in the abandoned and efficient materials that can continuously split water molecules using solar energy. In this report, an ammonium thiomolybdate (ATM: (NH4)2Mo3S13) is evaluated as a p-type semiconductor film photocathode for hydrogen evolution reaction. The ATM thin films are prepared by spin-coating on fluorine-doped tin oxide substrates, and their structural, morphological, optical, photoelectrical, and photoelectrochemical (PEC) properties are studied. Transient surface photovoltage (TSPV) spectroscopy and spectroscopic ellipsometry indicate the band gap Eg= 1.9 eV for the ATM thin films. Furthermore, the photovoltage of the ATM thin films measured by TSPV is correlated to the photocurrents measured by the PEC characterization that can be used to evaluate the material potential for hydrogen generation. The films exhibit a low photocurrent density of 46 μA cm–2at 0 VRHE. However, its combination with WSe2thin-film photocathodes results in a significant increase in photocurrent density up to 4.6 mA cm–2at 0 VRHE(100 times). The reason for such a strong charge carrier transfer effect for ATM/WSe2heterojunction photocathodes is studied by TSPV spectroscopy that allows a comprehensive evaluation of potential photovoltaic materials toward PEC hydrogen production. Furthermore, the photovoltage generated by a WSe2thin film is 30 times lower than that of its single crystal, which indicates that the quality of WSe2thin films should be improved for faster PEC hydrogen evolution.

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Intermetallicceramic composites represent an interesting class of materials for high-temperature structural and functional applications. These materials can be prepared via high-energy milling of pure metals with Al2O3as well as of aluminum with metal oxides. During subsequent compaction via pressureless sintering, the components react to form dense composites that consist of interpenetrating networks of the ceramic and intermetallic phases. Microstructural investigations, mechanical properties, and resistivity and wear resistance measurements of selected composites are presented. Improved fracture toughness and bending strength, with respect to monolithic Al2O3, have been achieved.

RésuméLe vieillissement de la population fait en sorte que les politiques concernant les personnes âgées attirent de plus en plus l'attention des gouvernements. Aux États-Unis, les deux principaux programmes pour les personnes âgées sont le programme d'assurance-vieillesse du volet sécurité sociale et le programme Medicare. The New Politics of Old Age Policy examine les enjeux liées ces programmes aux nouvelles conditions démographiques. Le thème du livre porte sur le degré de responsabilité de l'État plutôt que celles des individus en ce qui a trait au soutien des personnes âgées. En général, le livre est une introduction intéressante à la politique de sécurité du revenu aux États-unis. Toutefois, ses nombreuses répétitions, le traitement superficiel des sujets et son manque de cohérence en limite quelque peu la portée.

A letter to the editor is presented in response to the article "No Country for Old Men" which appears in the January 10, 2015 issue and addresses Canada's immigration policy which gives priority to those immigrants who possess job offers, and it mentions the needs of the nation's labour market.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.