Contents of eight harmful elements in baby toys and their migration tests

Levels of eight harmful elements, i.e., antimony, arsenic, barium, cadmium, chromium, lead, mercury and selenium, were investigated in 45 baby toys and 10 paints, which were mainly made of polyvinyl chloride. All samples contained barium at levels of 0.3-3,700 mg/kg, several samples contained cadmium (0.2-26 mg/kg), chromium (0.5-280 mg/kg) and lead (1.5-1,300 mg/kg), and one sample contained antimony (5.3 mg/kg). They might have been used as colorants of the toy materials and paints. They were then evaluated using the migration test of ISO 8124-3, in which samples were ground up, and then soaked in 0.07 mol/L HCl at 37 degrees C for two hours. Barium, cadmium, chromium and lead migrated from some of the samples, but at levels lower than the migration limits required by ISO 8124-3. Compared with the Japanese official method, the ISO method resulted in higher migration, but there are significant differences in the migration limits, test method, and so on between them. Further investigation is needed in this area.     

Strain-induced structural transformation of a silver nanowire

We have investigated the structural characteristics of the experimentally observed phase transition of a silver nanowire into a tube under tensile strain. In the simulations, atoms are allowed to interact via a model potential extracted from the modified embedded atom method. Our calculations demonstrate that the formation of the hollow structure is governed by the nature of the applied strain, the length of the wire, and the initial cross-sectional shape. The results further offer insights into the atomistic nature of this specific structural transformation into a nanotube with the smallest possible cross-section.     

Effect of High-Pressure Torsion Processing and Annealing on Hydrogen Embrittlement of Type 304 Metastable Austenitic Stainless Steel

The effect of high-pressure torsion (HPT) and annealing on hydrogen embrittlement (HE) of a type 304 stainless steel was studied by metallographic characterization and tensile test after hydrogen gas charging. A volume fraction of ~78 pct of the austenite transformed to α′ martensite by the HPT processing at an equivalent strain of ~30. Annealing the HPT-processed specimen at a temperature of 873 K (600 °C) for 0.5 hours decreased the α′ martensite to ~31 pct with the average grain size reduced to ~0.43 μm through the reverse austenitic transformation. Hydrogen charge into the HPT-processed and the HPT+annealed specimens in the hydrogen content of ~10 to 20 ppm led to no severe HE but appeared in the solution-treated specimen. Especially the 873 K (600 °C) annealed specimen had the ~1.4 GPa tensile strength and the ~50 pct reduction of area (RA) despite the hydrogenation.     

Investigation of the relation between surface roughness and friction properties of polyester fabrics after abrasion

This paper focused on the investigation of surface roughness and friction properties of polyester fabrics after abrasion. Experiments were performed on polyester woven fabrics produced from the same yarns in warp and weft directions but with different constructional properties. Surface roughness parameters of amplitude, spacing and hybrid, along with static and kinetic coefficients of friction were measured before and after multiple abrasion cycles. Abrasion was used in order to change the surface characteristic (peak and valley heights and depths and their distributions) in such a way by forming ruptured fiber ends under the control of abrasion. Measurements were made along warp, weft, and diagonal directions. The results showed that roughness parameters decreased numerically as abrasion cycles increased and as ruptured fiber ends formed. Static and kinetic coefficients of friction changed in different manners when measurements were performed along warp and weft directions. It was concluded that initial and resultant peak heights and valley depths together with their distribution on fabric surface govern roughness and friction properties of surfaces in opposite ways. Roughness parameters of skewness and kurtosis could be further considered in the research of friction properties of textile surfaces.     

Effect of urban transformation on the values of historic sites around mosques:Two cases in Manisa,Turkey

This study presents a framework for assessing the cultural asset values of historic sites around mosques. Case studies are selected from provinces of Manisa, Turkey, namely, Çarşı in Salihli with its new urban development and Pazaryeri in Gördes that is abandoned and currently considered as an archaeological site. Literature review, archive research, historical research, comparative study, and site survey are carried out to evaluate the urban development of site neighborhoods with a retrospective perspective. An approach presenting the effects of urban transformations on the cultural asset values of the historic neighborhood centers is proposed. The cases reveal that the urban aesthetic is nearly all lost today, but the holiness of each site preserves its authenticity while the historic land use is sustained. Their preservation problems are lack of maintenance and abandonment due to disasters, illegal interventions, inappropriate development plans, and unsuitable restoration approaches. The principles proposed for managing these historic environments consider their cultural asset values in relation to urban history, development of coherent strategies for their presentation, and participation of all actors to their preservation and development.     

Critical assessment of methods for measurement of temperature profiles and heat load history in microwave heating processes—A review

Limitations of microwave processing due to inhomogeneities of power input and energy absorption have been widely described. Over- and underheated product areas influence reproducibility, product quality, and possibly safety. Although a broad range of methods is available for temperature measurement and evaluation of time/temperature effects, none of them is sufficiently able to detect temperature differences and thermally induced effects within the product caused by inhomogeneous heating. The purpose of this review is to critically assess different methods of temperature measurement for their suitability for different microwave applications, namely metallic temperature sensors, thermal imaging, pyrometer measurement, fiber optic sensors, microwave radiometry, magnetic resonance imaging, liquid crystal thermography, thermal paper, and biological and chemical time-temperature indicators. These methods are evaluated according to their advantages and limitations, method characteristics, and potential interference with the electric field. Special attention is given to spatial resolution, accuracy, handling, and purpose of measurement, that is, development work or online production control. Differences of methods and examples of practical application and failure in microwave-assisted food processing are discussed with a special focus on microwave pasteurization and microwave-assisted drying. Based on this assessment, it is suggested that infrared cameras for measuring temperature distribution at the product surface and partially inside the product in combination with a chemical time/temperature indicator (e.g., Maillard reaction, generating heat-induced color variations, depending on local energy absorption) appear to be the most appropriate system for future practical application in microwave food process control, microwave system development, and product design. Reliable detection of inhomogeneous heating is a prerequisite to counteracte inhomogeneity by a targeted adjustment of process and product parameters in microwave applications.     

煤层坚硬顶板综采面初次放顶爆破技术

本文介绍了顾北矿1212(1)综采工作面切眼松动爆破强制放顶技术,圆满地解决了初放期间的顶板管理问题,取得了较好的安全效益。     

Maintenance of safety and quality of refrigerated ready-to-cook seasoned ground beef product (meatball) by combining gamma irradiation with modified atmosphere packaging

Abstract: Meatballs were prepared by mixing ground beef and spices and inoculated with E. coli O157:H7, L. monocytogenes, and S. enteritidis before packaged in modified atmosphere (3% O₂+ 50% CO₂+ 47% N₂) or aerobic conditions. The packaged samples were irradiated at 0.75, 1.5, and 3 kGy doses and stored at 4 °C for 21 d. Survival of the pathogens, total plate count, lipid oxidation, color change, and sensory quality were analyzed during storage. Irradiation at 3 kGy inactivated all the inoculated (approximately 10⁶ CFU/g) S. enteritidis and L. monocytogenes cells in the samples. The inoculated (approximately 10⁶ CFU/g) E. coli O157:H7 cells were totally inactivated by 1.5 kGy irradiation. D¹⁰‐values for E. coli O157:H7, S. enteritidis, and L. monocytogenes were 0.24, 0.43, and 0.41 kGy in MAP and 0.22, 0.39, and 0.39 kGy in aerobic packages, respectively. Irradiation at 1.5 and 3 kGy resulted in 0.13 and 0.36 mg MDA/kg increase in 2‐thiobarbituric acid‐reactive substances (TBARS) reaching 1.02 and 1.49 MDA/kg, respectively, on day 1. Irradiation also caused significant loss of color and sensory quality in aerobic packages. However, MAP effectively inhibited the irradiation‐induced quality degradations during 21‐d storage. Thus, combining irradiation (3 kGy) and MAP (3% O₂+ 50% CO₂+ 47% N₂) controlled the safety risk due to the potential pathogens and maintained qualities of meatballs during 21‐d refrigerated storage. Practical Application: Combined use of gamma irradiation and modified atmosphere packaging (MAP) can maintain quality and safety of seasoned ground beef (meatball). Seasoned ground beef can be irradiated at 3 kGy and packaged in MAP with 3% O₂+ 50% CO₂+ 47% N₂ gas mixture in a high barrier packaging materials. These treatments can significantly decrease risk due to potential pathogens including E. coli O157:H7, L. monocytogenes, and S. enteritidis in the product. The MAP would reduce the undesirable effects of irradiation on quality, and extend the shelf life of the product for up to 21 d at 3 °C.     

Hydrogen uptake in austenitic stainless steels by exposure to gaseous hydrogen and its effect on tensile deformation

Hydrogen solubility and diffusivity of Fe–Cr–Ni austenitic stainless steels were measured through exposure to gaseous hydrogen at a pressure of 10 MPa over the temperature range 110–235 °C. The hydrogen solubility depended on the alloy compositions, whereas the diffusion coefficients were nearly identical at a given temperature. Hydrogen uptake in the stable austenitic steels by exposure to high-pressure gaseous hydrogen led to some loss of ductility, while their fracture surfaces showed evidence of plastic deformation. This was attributed to the enhanced inhomogeneity of plastic deformation in the presence of hydrogen and the increased stress for plastic instability with increasing hydrogen concentration.     

The analysis of leakage current in MIS Au/SiO2/n-GaAs at room temperature

The aim of this study is to determine the reverse-bias leakage current conduction mechanisms in Au/SiO₂/n-GaAs metal-insulator-semiconductor type Schottky contacts. Reverse-bias current-voltage measurements (I–V) were performed at room temperature. The using of leakage current values in SiO₂ at electric fields of 1.46–3.53 MV/cm, ln(J/E) vs. $\sqrt E $ graph showed good linearity. Rom this plot, dielectric constant of SiO₂ was calculated as 3.7 and this value is perfect agreement with 3.9 which is value of SiO₂ dielectric constant. This indicates, Poole-Frenkel type emission mechanism is dominant in this field region. On the other hand, electric fields between 0.06–0.73 and 0.79–1.45 MV/cm, dominant leakage current mechanisms were found as ohmic type conduction and space charge limited conduction, respectively.