Ti/TiO<Subscript>2</Subscript> nanotube array electrode as a new sensor to photoelectrocatalytic determination of ethylene glycol

The photoelectrocatalytic oxidation behaviour of ethylene glycol (EG) was studied in the present work using the TiO₂-modified Ti foil (Ti/TiO₂) electrode. The Ti/TiO₂ nanotube array (Ti-NTA) electrode was prepared by anodizing of the Ti foil in the HF aqueous solution (0.2% v/v). The anodization was conducted in the constant 30 V for 2 h, and then the as-prepared Ti-NTA electrode was calcinated at 50 ^° C for 2 h. The surface morphology of Ti- NTA electrode was studied using scanning electron microscopy images. For EG determination, the photocurrent of EG (EG oxidation current in the UV irradiation) was assessed using the hydrodynamic photoamperometric method in the phosphate buffers. Ultimately, the optimum conditions of EG determination were studied in various pH values and applied bias potentials, and the pH = 3.0 and E= 1.0 V (vs. reference electrode) were determined as the optimum conditions. It was found that the photocurrent of EG was linearly dependent on the concentration of EG in the range of 3.0 × 10 ^?5 to 0.88 mol l ^?1 , and the detection limit of EG determination was found to be 7.2 × 10^?6 mol l^?1 (3 σ).     

Preparation and characterization of silver nanoparticles in natural polymers using laser ablation

In this paper we have done a comparative study on efficiency of natural polymers for stabilizing silver nanoparticles (Ag-NPs) prepared by laser ablation technique. The selected polymers are starch (St), gelatin (Gt) and chitosan (Ct). The fabrication process was carried out through ablation of a pure Ag plate by nanosecond Q-switched Nd?CYg pulsed laser (?? = 532?nm, 360?mJ/pulse). The stability of the samples was studied by measuring UV-visible absorption spectra of the samples one month after preparation. The result showed that the formation efficiency of NPs in St were highest and also the prepared NPs in St solution were more stable than other polymers during one month storage.     

模糊环境下汽车故障模式风险水平综合评价方法

针对车辆故障模式风险评价,提出了一种新的模糊综合评价方法,即先利用基于维修数据的失效模式与效果分析(FMEA)筛选出关键故障模式进行进一步研究,再分别采用模糊层次分析法(AHP)与模糊扩展全乘比例多目标优化(MULTIMOORA)计算风险评价因素与故障模式的权重,通过计算车辆故障模式的最终权重得到故障模式进行风险排序.同时利用逻辑语言表征评审专家的评估信息并将其转化为三角模糊数,实现了客观维修数据与专家经验判断的有机结合.利用本文提出的新评价方法对现代一款轻型客车进行故障模式风险评估与排序,进行灵敏度分析验证此方法的有效性.     

Use of Ultrasound to Determine Cod Fillet Composition

The relationships between the composition and ultrasonic properties of Atlantic cod (Gadus morhua) fillets were examined. The lipid, protein, moisture and ash contents of cod fillets were determined by official methods. The ultrasonic velocity and attenuation coefficient of the fillets were measured using a pulse-echo technique. The ultrasonic velocity of the fillets varied between 1575 and 1595 m s^?1, decreasing linearly with increasing moisture content (r² > 0.8 for 26 samples). No systematic relationship was observed between the attenuation coefficient and moisture content. Our experiments highlight the potential of using ultrasonic velocity measurements to rapidly and nondestructively determine the moisture content of cod fillets (and possibly their protein content by deduction).     

搅拌摩擦加工制备具有单一和混合表面的Al5083/CeO_2/SiC复合材料的显微组织和磨损行为（英文）

利用搅拌摩擦加工(FSP),将纳米尺寸的氧化铈(CeO_2)和碳化硅(SiC)颗粒以单独和混合形式嵌入Al5083合金基体,制备表面复合材料,并研究这些增强相对合成的表面复合层显微组织和耐磨性能的作用。在室温下用销-盘式磨损试验机检测合成的单独和混合表面复合层的磨损特性。用光学显微镜和扫描电镜观察FSPed区和磨损表面的显微组织。在熔核区可观察到显著的晶粒细化和均匀分布的增强颗粒。与基体金属相比,所有复合材料都具有更高的硬度和更好的耐磨性。其中,混合复合材料Al5083/CeO_2/SiC的耐磨性能最好,摩擦因数最低,而Al5083/SiC的硬度最高,是Al5083基体合金硬度的1.5倍。混合复合材料表面耐磨性能的提高是由于CeO_2颗粒的固体润滑效果。非复合材料中主要的磨损机制是严重的粘着磨损,当存在增强颗粒时转变为磨粒磨损和分层。     

Influence of starter culture type and incubation temperatures on rheology and microstructure of low fat set yoghurt

The effects of different cultures and incubation temperatures on the physical properties of low fat yoghurts were investigated. The samples were incubated with exopolysaccharide (EPS)-producing and non-EPS-producing cultures at 37, 42 and 45°C. All measured parameters except firmness were influenced by culture type and incubation temperature. Firmness, G' and G" were maximised at 42°C for both cultures. Increased incubation temperature and EPS culture led to a higher water-holding capacity but lower syneresis, G' and G". The EPS treatment incubated at 37°C showed even lower syneresis than non-EPS treatments incubated at higher temperatures.     

Thermal characteristics and corrosion behaviour of Mg–xZn alloys for biomedical applications

The thermal parameters of Mg–xZn cast alloys with 0·5–9 wt% Zn were evaluated by using computer aided cooling curve thermal analysis (CA–CCTA), whereas the corrosion behaviour was investigated by potentiodynamic polarization and immersion tests. Thermal analysis results revealed that the dendrite coherency temperature (T _DCP ) decreased from 642·2 to 600 °C with the addition of Zn from 0·5 to 9 wt%. The liquid fraction at coherency point ( ${f}_{ L}^{ DCP}$ ) increased by 72% when Zn was increased up to 9 wt%. MgZn intermetallic phase was observed in samples with <3 wt% Zn. At higher percentages of Zn, the Mg ₅₁Zn ₂₀ intermetallic phase was also detected in addition to α-Mg and MgZn by first derivative cooling curves under non-equilibrium solidification. All these phases were observed along the grain boundary when Zn was rejected from the solid/liquid interface and enriched in the triple conjunction of grain boundary. The grain size decreased from 185·2 to 71·5 μm when Zn content was increased. The addition of Zn content had a significant effect on the corrosion rate and the corresponding mechanisms. The corrosion rate decreased from 2·1 to 1·81 mmpy as Zn content increased from 0·5 to 3 wt%; afterwards, however, this value increased with further increase of Zn. Mg–3Zn also had the lowest degradation rate and highest corrosion resistance which can be fully utilized for biodegradable orthopedic applications.     

Stagnation point flow and heat transfer for a viscoelastic fluid impinging on a quiescent fluid

A theoretical study is made in the region near the stagnation point when a lighter incompressible viscoelastic fluids impinges orthogonally on the surface of another quiescent heavier incompressible viscous fluid. Similarity solutions of the momentum balance equations for both fluids are equalized at the interface. It is noted that an exact boundary layer solution is obtained for the lower lighter fluid. The velocity of the lower fluid is independent of lateral interface velocity but the velocity of the upper viscoelastic fluid increases with increasing lateral interface velocity. It is observed that lateral interface velocity increases with increasing viscoelastic parameter for fixed values of density and viscosity ratio of the two fluids. The convective heat transfer is investigated base on the similarity solutions for the temperature distribution of the two fluids. The interface temperature increases with increasing viscoelastic parameter of the upper viscoelastic fluid.