Deformation of specimen during laser surface remelting

During laser surface remelting, thermal expansion in heating, and contraction of material in cooling, and due to microstructure changes in the heated surface layer, the specimen deforms. This induces volume changes during the process of remelting the thin surface layer and causes internal stresses. By measuring the deformation of the specimen during the remelting process as well as after the laser beam interaction, i.e., to the moment when the specimen cools down to the ambient temperature, it is possible to follow the progress of deformation in the specimen material. Detailed information on the deformation events in the specimen material during the laser remelting process of a thin surface layer enables the engineer to optimize the process variables in terms of amount of deformation or magnitude of residual stresses on completion of cooling.     

Comparison of two micromechanical models for predicting elasto-plastic response of wood–plastic composites

The mechanical response of wood- and cellulose-filled polymers and its comparison to analytical models is studied in this article. To model the elasto-plastic response of the wood–plastic composite (WPC), two explicit semi-analytical micromechanical methods were used: Mori–Tanaka Method (MTM) and Generalised Method of Cells (GMC). For experimental purpose, several test specimens composed of matrix polypropylene (PP) or polystyrene (PS) and filled with wood or cellulose short fibres of different length to width aspect ratio and various volume fractions were injection moulded. Tensile testing was then used to gain experimental data, which were then compared to the calculated prediction of proposed micromechanical models to test their applicability. The comparison of results show that both methods can accurately predict the response of the composite in the elastic area; however Mori–Tanaka Method can achieve better results when forecasting plastic deformations of wood–plastic composites.     

User-centred app design for speech sound disorders interventions with tablet computers

Traditional speech and language pathology practice (SLPP) faces challenges delivering effective and timely therapy due to long waiting lists, the need for regular practice outside the clinic and a lack of children’s motivation to engage in persistent practice. Technology has untapped potential to address these issues and improve SLPP. This paper describes the design of a tablet app for delivering technology-enhanced therapy for children with speech sound disorders and investigates the impact of the use of apps on SLPP. The initial design was informed by a nation-wide survey of speech-language pathologists (SLPs). The quantitative analysis disclosed that even though SLPs positively perceive mobile technology, they do not currently fully exploit it in their practice due to a lack of apps in their native language and the limited usefulness of apps in foreign languages. Using a user-centred design process, a multidisciplinary team created three prototypes and a final version of an app that has been tested in real therapeutic sessions during everyday practice and informed by feedback from SLPs and children. The observation analysis is presented based on an adaptation of Koole’s FRAME model. The qualitative findings indicate that SLPs identify mobile apps as enabling greater mobility, allowing new therapeutic approaches, creating possibilities for practice outside the therapeutic setting and increasing children’s motivation, supporting greater persistence to practise in the context of the therapy.     

Overheating in residential passive house: Solution strategies revealed and confirmed through data analysis and simulations

Energy efficiency and living comfort certainly contribute to popularity of the passive house concept. Since these houses are weakly coupled to an environment, any internal energy gains are difficult to be released against small temperature gradients, i.e. in a typical situation occurring in hot summer months. In such a case already a small energy input raises the internal temperature significantly and dramatically affects the living comfort. To provide more information on this problem, we collected and analyzed data from a single family Slovenian passive house. Our goal was to estimate the general house response under real conditions and to investigate overheating in hot summer periods. Different energy gains were identified and explored with respect to their influence on the overheating of this passive house. Results show that windows-opening during the nights in hot summer days, strict shading of the southern and western windows as well as minimization of internal energy sources are necessary and sufficient to keep internal temperature on the comfort level.     

Subsolidus phase equilibria in the RuO2-Bi2O3-ZrO2 system

Subsolidus equilibria in air in the RuO₂-Bi₂O₃-ZrO₂ system were studied with the aim of obtaining information on possible interactions between a Bi₂Ru₂O₇-based cathode and a ZrO₂-based solid electrolyte in solid-oxide fuel cells (SOFCs). No ternary compound was found in the system. The tie lines are between Bi₂Ru₂O₇ and ZrO₂, and between Bi₂Ru₂O₇ and gamma-Bi₂O₃—the ZrO₂ stabilised Bi₂O₃ phase, stable at temperatures over 710 °C.     

17O and 14N quadrupole coupling and the mechanism of the ferroelectric transition in diglycine nitrate

The ^I4N and ¹⁷0 quadrupole couplings in diglycine nitrate have been determined by proton- ¹⁴N and proton-¹⁷0 double resonance. The O─H──O bonded proton is moving between two off-centre sites in the H─bond above T_C and is frozen out in an off-centre site below T_C. The results show that the basic phase transition mechanism is a biasing of the flipping of the ─NH₃ groups around the C─N bondbetween two equilibrium orientations separated by ∼ 60° connected with a corresponding rotation of the NO₃^-; ions, an exchange of the ionic character of the two glycine molecules and a transfer of the O─H──O bonded proton.     

Anti-CD36 autoantibodies in thrombotic thrombocytopenic purpura and other thrombotic disorders: identification of an 85 kD form of CD36 as a target antigen

The presence of anti-CD36 antibodies in plasma of patients with thrombotic thrombocytopenic purpura (TTP), idiopathic thrombocytopenic purpura (ITP), and heparin-induced thrombocytopenia without/with thrombosis (HIT/HITT) has been examined by immunoblots, and a monoclonal antibody capture assay, the platelet-associated IgG characterization assay (PAICA). Results with PAICA showed that 73% (8/11) of patients with TTP were positive, and 71% (10/14) by immunoblots. With ITP, 20% (6/30) were positive by PAICA and 19% (3/16) by immunoblots; HIT, 30% (3/10) were positive by PAICA and 60% (6/10) by immunoblot; HITT, 50% (2/4) by PAICA and 100% (4/4) by immunoblot. Purification of CD36 by fast protein liquid chromatography (FPLC) from Triton X-100 extracts of normal platelet membranes resulted in the isolation of two different forms: the classic 88 kD form, and a second, lighter 85 kD form. Our data indicated that the patients' plasma autoantibodies reacted strongly with the 85 kD form. Conventional monoclonal and polyclonal antisera produced to the 88 kD form reacted strongly with the 88 kD form but weakly with the 85 kD form. These results confirm the possible importance of anti-CD36 antibodies in the pathophysiology of TTP and other thrombocytopenias and demonstrate the presence of a previously unrecognized target antigen for these antibodies.     

Effect of structural and acidity/basicity changes of CuO–CeO2 catalysts on their activity for water–gas shift reaction

The objective of this work was to investigate the influence of CuO loading and catalyst pretreatment procedure to derive an optimal CuO–CeO₂ catalyst for the water–gas shift reaction (WGS), and to study in detail structure– and surface acidity–activity relationships. Catalyst samples prepared by coprecipitation and a 10, 15 and 20 mol% CuO content were examined by XRD, BET and TPR/TPD analyses and subjected to pulse WGS activity tests in the temperature range of 180–400 °C. Strong structure–activity dependence in the WGS reaction was observed for all catalyst samples. It was established that increasing CuO content has a positive effect on H₂ production during the WGS reaction, due to favored CeO₂ reduction. Increasing calcination temperature on the other hand reduces the BET surface area, induced by CuO sintering and agglomeration of CeO₂ particles, resulting in a negative effect on H₂ production. Distinctive WGS activity dependence on surface acidity was observed and investigated.     

Hydrogen production from raw bioethanol over Rh/MgAl2O4 catalyst: Impact of impurities: Heavy alcohol, aldehyde, ester, acid and amine

The effect of various impurities added in a pure ethanol + water mixture was studied. The impurities chosen were acetic acid, diethylamine, butanol, butanal, ethyl acetate and diethylether. It was shown that the addition of diethylamine or butanal increases the ethanol conversion, compared to that obtained with a pure ethanol + water mixture, without changing the product selectivity. In the presence of the other impurities, butanol, ethylether and ethyl acetate, a strong deactivation of the catalyst with a decreased ethanol conversion was observed. Moreover, the selectivity in hydrogen was also strongly decreased, whereas an increase in intermediate products especially ethylene was observed. The deactivation was explained in terms of coke deposition at the catalyst surface. The poisoning effect induced by the presence of impurities can be classified in the following increasing order: diethylamine  butanal < no impurity < acetic acid < butanol < diethylether  ethyl acetate.