Antioxidant properties of durian fruit as influenced by ripening

The antioxidant properties of durian (Durio zibethinus Murr., cv. Mon Thong) at different stages of ripening were investigated using fluorometry, UV spectroscopy, and HPLC/DAD analyses. Total polyphenols, flavonoids, anthocyanins and flavanols in ripe durian were significantly higher (p < 0.05) than in mature and overripe fruits. Free polyphenols and flavonoids were at lower levels than hydrolyzed ones. Caffeic acid and quercetin were the dominant antioxidant substances in ripe durian. In these fruits, methanol extracts contained a relatively high capacity of 74.9 ± 7.1% inhibition using β-carotene-linoleic acid assay. Ferric-reducing/antioxidant power (FRAP) and cupric-reducing antioxidant capacity (CUPRAC) assays supported this finding. The correlation coefficients between polyphenols and antioxidant capacities of durian samples with all applied assays were about 0.98. In conclusion, the bioactivity of ripe durian was high and the total polyphenols were the main contributors to the overall antioxidant capacity.     

Investigation of scratch resistance of thin carbon overcoat media using micro scratch testing

This paper investigates the scratch resistance of thin carbon overcoat media using a novel micro scratch testing method. Ramp loading was applied to a carbide blade, scratching along a rotating hard disk surface and the load corresponding to the penetration of the carbon overcoat, referred to as the critical load, was used as the measure of scratch resistance. The contact electric resistance (CER) at the cutting point of the blade/media interface was monitored through the scratch process and the critical load was determined when the CER dropped to zero. It has been found that CER monitoring is a very accurate and reliable way of determining the critical load. Scratches were characterized using scanning electronic microscopy (SEM) and it has been found that at the critical point the carbon overcoat was delaminated, peeled off, or plowed away. The micro scratch testing has shown to have the sensitivity to differentiate the effect of carbon thickness, carbon type, lubricant, and substrate type on media scratch resistance.     

Constrained thermoelastic martensitic transformation studied by modulated DSC

The constrained thermoelastic martensitic transformation of TiNiCu wires embedded in an epoxy matrix was studied by modulated differential scanning calorimetry (MDSC). Results showed that the non-reversing heat flow (NHF) signal of TiNiCu wires in a free condition is quite small whether the wires are pre-strained or not, while the NHF signal of the TiNiCu wires embedded in the epoxy matrix increases significantly with increasing level of pre-strain. Analysis showed that this significant increase of the NHF value is related to a term which is a function of the stress rate (dσ/dT). If the interface is perfectly bonded, this term contributes to the reversing heat flow (RHF) signal, while if the interface is debonded, this term contributes to the NHF signal.     

Experimental and numerical study of the effect of caul-sheets on corner thinning of composite laminates

Caul-sheets are used to locally reduce or intensify the pressure exerted on composite laminates during autoclave processing. They are often introduced into the process in the last minute to address manufacturing problems as they occur in production. There are multitudes of caul geometries and caul materials used in industry, often quite different, but intended to give the same end result, a well consolidated laminate, free of voids and with uniform thickness. This paper presents the results of an experimental and modelling study where the thickness of composite laminates made with five different caul-sheet configurations was measured and modelled. The experimental study showed that the type of caul-sheet has a significant effect on the resulting thickness profile, and particularly corner thinning. Modelling of corner thinning was done using a special purpose finite element code. Despite the approximations made in the finite element model, the model predictions were qualitatively in agreement with the experimental results, with the model being able to rank the caul-sheets in terms of effectiveness. A simple mechanistic model illustrating what is believed to be the main mechanisms behind thickness variations is also presented.     

Smart windows and intelligent glass façades

Human well being is strongly related to energy use, especially electricity use. The relationship is often expressed in terms of the United Nation's Human Development Index, which shows that countries with high life expectancy, good adult literacy and school enrolment, and large per-capita gross domestic product (GDP) consume at least 4000 kWh of electricity annually for each person.     

Application of chaos analysis to multiphase reactors

It is shown that chaos analysis provides valuable tools to improve the design and operation of multiphase reactors, the most useful tools being the system's attractor and the Kolmogorov entropy. Applications of chaos analysis are based upon examining the attractor shape and/or on a characterization of the attractor by the Kolmogorov entropy. Examples are given by the characterization of regimes and regime transitions, scale up, control of the bubble pattern in the reactor to influence selectivity and conversion of chemical reactions, and the development of a tool to early detect agglomeration in fluidized beds.     

Effects of atomic layer deposition conditions on the formation of thin ZnO films and their photocatalytic characteristics

The use of photocatalysts in water treatment systems is regarded as an advanced technology. To ensure efficiency and stability, the optimization of photocatalyst immobilization is essential for application in water treatment processes. In this study, we investigated the effect of atomic layer deposition (ALD) conditions on the development of highly photocatalytically active thin ZnO films. Three different temperatures and three ALD cycles were employed to evaluate the photocatalytic activity of thin ZnO films (represented by the production rate of reactive oxygen species and the degradation rate of methylene blue). We found that the surface properties of the thin ZnO films, such as grain size and homogeneity, exerted a dominant influence on the photocatalytic activity. At a low temperature (50 °C), nanograins were not formed properly, while various nanograin shapes were obtained at a high temperature (250 °C). The optimized grain had a grain size of 20 nm and a (002)/(101) crystalline orientation ratio of 2.2. The UV light absorption increased in proportion to the film thickness, and a minimum film thickness (50 nm) was necessary to ensure high photocatalytic activity at the film surface. In addition, the increase in the photocatalytic activity was not significant as the thickness increased beyond the optimum thickness. These results will provide useful guidelines for the fabrication of thin ZnO films with excellent photocatalytic activity for water treatment.     

Use of the finite elements method for modelling the dynamic load impact on hydraulic leg equipped with gas accumulator

Procedures of preparation of numerical analysis, consisting in a simulation of cooperation of three different media: steel, liquid and gas undergoes dynamic load were discussed. Modelling of the initial static load of the mechanical system was presented. By using the MSC. Software products the following exemplary computer simulations were made: dynamic load impact on the hydraulic leg as well as effectiveness of the hydraulic leg protection against overload with help of gas accumulator.     

Wavelet transform-based stress-time history editing of horizontal axis wind turbine blades

Full scale blade fatigue testing is required to verify that the horizontal axis wind turbine (HAWT) blades posses the strength and service life specified in the design. Unfortunately, fatigue tests must be run for a long time period, which has led blade testing laboratories to seek ways of accelerating fatigue testing time and reducing the costs of tests. The objective of this article is to develop a novel method called a WT-based fatigue damage part extracting method. Based on wavelet transform (WT), this method extracts fatigue damage parts from the stress-time history and generates the edited stress-time history with shorter time length. Also, this article proposes a concept of applying accumulative power spectral density (AccPSD) to identify fatigue damage events contained in the stress-time history of HAWT blades. Wavelet functions used in this study are Morl, Meyr, Dmey, Mexh and DB30. It has been found that Mexh wavelet with an AccPSD level of 9000 Energy/Hz provides the edited stress-time history having a maximum reduction of 20.77% in length with respect to the original length, whilst fatigue damage per repetition can be retained almost the same as the original one. In addition, an existing method, time correlated fatigue damage (TCFD), is used to validate the effectiveness of a WT-based fatigue damage part extracting method. The results suggest that not only does the WT improve the accuracy of fatigue damage retained, but also it provides a shorter length of the edited stress-time history. To conclude, WT is suggested as an alternative technique in fatigue durability study, especially for the field of wind turbine engineering.