Fabrication and characterization of ZrO2–CaO–P2O5–Na2O–SiO2 bioactive glass ceramics

SiO₂–CaO–Na₂O–P₂O₅–ZrO₂ based bioactive glasses with different compositions of SiO₂ and yttrium stabilized ZrO₂ were prepared by the conventional melt quenching technique. The effects on the chemical–mechanical properties of bioactive glasses due to the addition of ZrO₂ by replacing SiO₂ were investigated. Microstructure and phase behavior were studied by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction analysis. Compressive strength, porosity, Vickers hardness, and Young’s modulus were measured as mechanical properties. Bioactivity and cell viability were investigated by immersion in simulated body fluid and MTT assay analysis. Osteosarcoma cell proliferation on the specimen surfaces was examined by confocal laser scanning microscopy. The results showed that replacing SiO₂ with ZrO₂ helps the bioactive glass to be completely vitrified at comparatively lower sintering temperature than conventional Bioglass^®. The mechanical properties were also improved without compromising biocompatibility. Bioactive glass containing 10 wt% ZrO₂ and 35 wt% SiO₂ showed compressive strength of 399.71 MPa, Young's modulus of 22.3 GPa, Vicker’s hardness of 502.54 HV, and porosity of 26 vol%.     

Fluid flow with abrupt viscosity-temperature dependence

The paper is focused on studies of channel viscous flow stability with the high dependence viscosity on temperature (thermoviscosity effect). It is shown the essential influence of this effect on the entrance length or transition from any initial profile to the stationary profile of the plane channel flow. The obtained solution has an inflection point in the velocity profile for the certain range of flow parameters. This evidence with respect to Rayleigh’s inflection theorem involves thermoviscous media deserving consideration objects for stability problems.     

Quantitative Evaluation Method for Etch Sidewall Profile of Through‐Silicon Vias (TSVs)

Through‐silicon via (TSV) technology provides much of the benefits seen in advanced packaging, such as threedimensional integrated circuits and 3D packaging, with shorter interconnection paths for homo‐ and heterogeneous device integration. In TSV, a destructive cross‐sectional analysis of an image from a scanning electron microscope is the most frequently used method for quality control purposes. We propose a quantitative evaluation method for TSV etch profiles whereby we consider sidewall angle, curvature profile, undercut, and scallop. A weighted sum of the four evaluated parameters, nominally total score (TS), is suggested for the numerical evaluation of an individual TSV profile. Uniformity, defined by the ratio of the standard deviation and average of the parameters that comprise TS, is suggested for the evaluation of wafer‐to‐wafer variation in volume manufacturing.     

A Synthetic Approach to Oligomeric Phenylethynylsilylenes

Oligomers consisting of alternating phenylethynyl and monosilyl or disilanyl moieties were synthesized in 15–64% precipitated yields by the reactions of dilithiated ethynylbenzene with dichlorodimethylsilane, dichlorodiphenylsilane, and 1,2-dichloro-1,1,2,2-tetramethyldisilane. Degrees of polymerization were fairly low due to chain termination reactions involving the deprotonation of ethynyl groups by aryllithium species. The presence of butyl chain ends was confirmed by ¹H and ²⁹Si NMR spectroscopy. ²⁹Si NMR spectroscopy was utilized to illustrate the random pattern of connectivity along the oligomer backbones. The oligomers exhibit fluorescent behavior in solution.     

Fingerskate: Relaxing the Physical Constraint of Two-Finger Touchscreen Operations

Two-finger operations, such as rotation operations and zoom operations, are now standard touchscreen operations. However, these two-finger operations may pose an ergonomic problem when they are performed with one hand. FingerSkate is an interaction technique to mitigate the ergonomic problem of two-finger operations adopting the concept of gesture relaxation. A preliminary study showed that the FingerSkate technique was accepted well by the participants. In particular, a micro-analysis of finger movements during the study showed that FingerSkate was utilized well for large rotations. In a subsequent user study, the effects of two FingerSkate design options, Concurrency and Pivot, were examined. The Concurrency option had a statistically significant effect on performance and task workload for a docking task. The Pivot option had a statistically significant effect on task workload for a puzzle task. More participants preferred the sequential Concurrency option, and most participants preferred the center-of-object Pivot option.     

Electrical discharges with liquid electrodes used in water decontamination

The results of experimental investigation of the DC electrical discharge with moving air bubbles in the electrolyte, as well as of high frequency electrical discharge with a diaphragm membrane, within a wide parameter range are presented. We investigated active component formation and enhancement of the wastewater decontamination by means of production of a disinfecting agent with a maximal content of the electrical discharge products (copper and silver ions and hydrogen peroxide).     

The influence of calcination temperature on catalytic activities in a Co based catalyst for CO2 dry reforming

The carbon dioxide dry reforming of methane (CDR) reaction could be thermodynamically favored in the range of 800 to 1,000 °C. However, the catalyst in this reaction should be avoided at the calcination temperature over 800 °C since strong metal support interaction (SMSI) in this temperature range can decrease activity due to loss of active sites. Therefore, we focused on optimizing the temperature of pretreatment and a comparison of surface characterization results for CDR. Results related to metal sintering over support, re-dispersion by changing of particle size of metal-support, and strong metal support interaction were observed and confirmed in this work. In our conclusion, optimum calcination temperature for a preparation of catalyst was proposed that 400 °C showed a higher and more stable catalytic activity without changing of support characteristics.     

Effect of Sintering Temperature on Thermoelectric Properties of p‐Bi2Te3 Alloys Produced by Gas Atomization

In this research, p‐type Bi₂Te₃–75% Sb₂Te₃ thermoelectric alloy powders were produced by gas atomization and subsequently sintered by hot pressing at different temperatures. The grain growth of the hot‐pressed samples was observed with increasing sintering temperature from 380°C to 460°C. The compressive strength increased with increasing hot‐pressing temperature due to the high relative density of bulk samples obtained at high temperatures. The effect of sintering temperature on thermoelectric (TE) properties was studied. The maximum power factor 3.48 mW/mK² was obtained for the sample hot pressed at 420°C due to the resulting high electrical conductivity and enhanced Seebeck coefficient values.