Influence of alloying and microstructure on the electrochemical hydriding of TiNi-based ternary alloys

Nanostructured ternary TiNi-type alloys, namely Ti_0.8M_0.2Ni (M = Zr, V), TiNi_0.8N_0.2 (N = Cu, Mn) and TiNi_1−x Mn _x (x = 0.2, 0.4, 0.6, 1.0), were synthesized by mechanical alloying. Depending on the intensity and time of milling alloys with different microstructure were obtained. The as-milled TiNi_1−x Mn _x alloys contain substantial amount of amorphous phase, which crystallizes during annealing. Annealing of the as-milled fine nanocrystalline materials at 500 °C results only in slight coarsening of the microstructure, which remains still nanocrystalline. Fully crystalline material (with crystal size larger than 50 nm), consisting of mainly cubic TiNi was obtained by annealing the ball-milled alloys at T ≥ 700 °C. Electrochemical hydrogen charge/discharge cycling of the as-milled as well as of annealed alloys were carried out at galvanostatic conditions. It was found that among the nanocrystalline Ti_0.8M_0.2Ni_0.8N_0.2 (M = Zr, V; N = Cu, Mn) alloys TiNi_0.8Mn_0.2 revealed the highest discharge capacity of 56 mAh g⁻¹ in the as-milled state and 75 mAh g⁻¹ after short-time annealing at 500 °C. Annealing at higher temperature does not increase the capacity further. The as-milled TiNi_1−x Mn _x alloys with x ≤ 0.4 reveal noticeably higher discharge capacity and better cycle life than the Mn-richer alloys. Based on potentiostatic experiments the diffusion coefficients of hydrogen into TiNi alloys in two different microstructural states (fine and coarser nanocrystalline) as well as in as-milled amorphous/nanocrystalline and nanocrystalline TiNi_0.8Mn_0.2 were determined. The hydrogen diffusion coefficients of the TiNi alloys are comparable (1.9–2.7 × 10⁻¹² cm² s⁻¹). The diffusion coefficient in the as-milled amorphous/nanocrystalline TiNi_0.8Mn_0.2 was found to be 3–4 times higher than that of the as-milled nanocrystalline alloy.     

Cleaning Ability of Mixed Solutions of Sulfonated Fatty Acid Methyl Esters

Here, we present results from a systematic study on cleaning of oily deposits from solid surfaces (porcelain and stainless steel) by solutions of fatty acid sulfonated methyl esters (SME), sodium salts. The zwitterionic dodecyldimethylamine oxide (DDAO) has been used as a cosurfactant. As representatives of the vegetable and mineral oils, sunflower seed oil and light mineral oil have been used. The process of oil drop detachment from the solid substrates (roll-up mechanism) has been monitored. In the case of porcelain, excellent cleaning of oil is achieved by mixed solutions of SME and DDAO. In the case of stainless steel, excellent cleaning (superior than that by linear alkylbenzene sulfonate and sodium lauryl ether sulfate) is provided by binary and ternary mixtures of SME, which may contain also DDAO. For the studied systems, the good cleaning correlates neither with the oil/water interfacial tension, nor with the surfactant chainlength and headgroup type. The data imply that governing factors might be the thickness and morphology of admicelle layers formed on the solid/water interface. The results indicate that the SME mixtures represent a promising system for formulations in house-hold detergency, having in mind also other useful properties of SME, such as biodegradability, skin compatibility, and hard water tolerance.     

Sol-gel Ag + Pd/SiO2 as a catalyst for reduction of NO with CO

A catalyst with an ultra high iridium load was prepared using a method involving multiple impregnations. The obtained iridium catalyst contained between 29 and 35 wt% of 2 nm-sized nanoparticles dispersed on a support such as reinforced alumina, bauxite and precipitated alumina. XAFS suggested a possible structural model of Ir₄ surrounded by oxygen. The decomposition of hydrazine hydrate to its elements was used as a probe reaction. The results showed that a catalyst support with a high mechanical strength such as reinforced alumina and bauxite is essential for sustaining the decomposition reaction of hydrazine hydrate where there is a high degree of mechanical and thermal shock. The decomposition reaction of hydrazine monohydrate (N₂H₄ · H₂O) proceeded rapidly to generate a CO_x-free hydrogen-rich gas through contact with the iridium catalyst at room temperature.     

The Ephb2 Receptor Uses Homotypic,Head-to-Tail Interactions within Its Ectodomain as an Autoinhibitory Control Mechanism

The Eph receptor tyrosine kinases and their ephrin ligands direct axon pathfinding and neuronal cell migration, as well as mediate many other cell–cell communication events. Their dysfunctional signaling has been shown to lead to various diseases, including cancer. The Ephs and ephrins both localize to the plasma membrane and, upon cell–cell contact, form extensive signaling assemblies at the contact sites. The Ephs and the ephrins are divided into A and B subclasses based on their sequence conservation and affinities for each other. The molecular details of Eph–ephrin recognition have been previously revealed and it has been documented that ephrin binding induces higher-order Eph assemblies, which are essential for full biological activity, via multiple, distinct Eph–Eph interfaces. One Eph–Eph interface type is characterized by a homotypic, head-to-tail interaction between the ligand-binding and the fibronectin domains of two adjacent Eph molecules. While the previous Eph ectodomain structural studies were focused on A class receptors, we now report the crystal structure of the full ectodomain of EphB2, revealing distinct and unique head-to-tail receptor–receptor interactions. The EphB2 structure and structure-based mutagenesis document that EphB2 uses the head-to-tail interactions as a novel autoinhibitory control mechanism for regulating downstream signaling and that these interactions can be modulated by posttranslational modifications.     

A Technology Demonstrator for 1.6–2.0 THz Waveguide HEB Receiver with a Novel Mixer Layout

In this paper, we present our studies on a technology demonstrator for a balanced waveguide hot-electron bolometer (HEB) mixer operating in the 1.6–2.0 THz band. The design employs a novel layout for the HEB mixer combining several key technologies: all-metal THz waveguide micromachining, ultra-thin NbN film deposition and a micromachining of a silicon-on-insulator (SOI) substrate to manufacture the HEB mixer. In this paper, we present a novel mixer layout that greatly facilitates handling and mounting of the mixer chip via self-aligning as well as provides easy electrical interfacing. In our opinion, this opens up a real prospective for building multi-pixel waveguide THz receivers. Such receivers could be of interest for SOFIA, possible follow up of the Herschel HIFI, and even for ground based telescopes yet over limited periods of time with extremely dry weather (PWV less than 0.1 mm).     

Isotopes as clues to the origin and earliest differentiation history of the Earth

Measurable variations in (182)W/(183)W, (142)Nd/(144)Nd, (129)Xe/(130)Xe and (136)XePu/(130)Xe in the Earth and meteorites provide a record of accretion and formation of the core, early crust and atmosphere. These variations are due to the decay of the now extinct nuclides (182)Hf, (146)Sm, (129)I and (244)Pu. The (l82)Hf-(182)W system is the best accretion and core-formation chronometer, which yields a mean time of Earth's formation of 10Myr, and a total time scale of 30Myr. New laser shock data at conditions comparable with those in the Earth's deep mantle subsequent to the giant Moon-forming impact suggest that metal-silicate equilibration was rapid enough for the Hf-W chronometer to reliably record this time scale. The coupled (146)Sm-(147)Sm chronometer is the best system for determining the initial silicate differentiation (magma ocean crystallization and proto-crust formation), which took place at ca 4.47Ga or perhaps even earlier. The presence of a large (129)Xe excess in the deep Earth is consistent with a very early atmosphere formation (as early as 30Myr); however, the interpretation is complicated by the fact that most of the atmospheric Xe may be from a volatile-rich late veneer.     

Sol-gel synthesis,surface and magnetic properties of nanocrystalline SmAlO3

Nanocrystals of single-phase samarium monoaluminate (SmAlO3) were synthesized and studied for the first time. Malic acid was employed as a new complexing agent in the sol-gel process. The material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS), specific surface area and density. The lowest size of the nanoparticles was about 50–60 nm and some of them formed agglomerates. The binding energies of core-level electrons of Sm (3d, 4d, 4f, ...     

Some aspects of human-friendly control for movement-helping devices

Future welfare models should meet the needs of a large group of aged and disabled people. Present research and technology efforts in this direction are oriented toward the development of highly effective home-installed devices which will provide the user with continuous assistance in different everyday activities. The problems and needs of the elderly and the disabled vary from person to person over a large range, and with many serious requirements. Modern designs for such devices are oriented toward solutions where the user is less engaged in the control process, and the interaction between the device and the user ishuman-friendly, i.e., the devices should possess a high level of intelligence in their controls, actions, and interactions with the user, offering him/her a high level of comfort and functionality. This paper considers a mixed control mode as a better alternative for human-machine interactions for users with great movement disability. Some examples of easy direct control are discussed.