EFFECT OF GLUCOSE SYRUP SOLID, SUCROSE, HYDROGENATED PALM OIL AND SOY-LECITHIN ON SENSORY ACCEPTABILITY OF DURIAN LEATHER

A two-stage optimization of ingredients in durian leather formulations was conducted using Response Surface Methodology (RSM). In stage 1, the independent variables were glucose syrup solids (GSS) and sucrose, and in stage 2, the variables were hydrogenated palm oil (HPO) and soy-lecithin (SL). Based on the responses to sensory acceptability attributes including taste, aroma, texture, appearance and overall acceptability, the most acceptable formulation was a combination of 10% GSS, 5% sucrose, 2.67% HPO and 0.452% SL. Chemical analysis also showed that during processing nutrient composition was relatively unchanged.     

Investigation of functionally graded metal foam thermal management system for solar cell

Concentrated photovoltaic cell (CPV) is a solar energy harvesting device that converts solar energy into electrical energy. However, the performance and efficiency of the CPV are heavily dependent on the temperature. Besides, nonuniformity of temperature distribution on the CPV will lead to thermal aging and affects the cycle life. Hence, an effective cooling system is required to remove excess heat generated to ensure that the CPV operates at optimum operating temperature with minimum variation of temperature. Metal foam is a new class of material that possesses huge potential for thermal management. In this study, a functionally graded metal foam is proposed for the CPV thermal management system. Computational thermal fluid dynamic analysis is conducted to investigate the effect of porosity and pore density on the flow field and thermal performance of the aluminum foam heat sink. The investigation results revealed that 10 PPI functionally graded aluminum foam heat sink with two stages of porosity gradient 0.794 and 0.682 produced the lowest pressure drop and highest thermal performance. Temperature difference of 3.9°C was achieved for a solar cell with total heat generation of 900 W under water mass flow rate of 20 gs⁻¹.     

Overload effects on fatigue crack‐tip fields under plane stress conditions: surface and bulk analysis

The surface crack opening displacements are characterised by digital image correlation for a (thin) plane stress 316 stainless steel compact tension sample subjected to an overload event. This supports a traditional plasticity‐induced closure interpretation showing a knee in the closure response prior to overload, an absence of closure in the accelerated growth regime followed by accentuated closure in the retardation regime. By contrast, measurement of the mid‐thickness elastic strain field behind and ahead of the crack made by synchrotron X‐ray diffraction shows no evidence of significant crack face contact stresses behind the crack tip on approaching minimum loading. Rather the changes during loading and overloading can mostly be explained by a simple elastic plastic analysis using a value of the yield stress intermediate between the initial yield stress and the UTS. This shows very significant compressive reverse plastic strains ahead of the crack that start to form early during unloading. At the moment it is not clear whether this difference is because of the increasing stress intensity applied as the crack grows, or for some other reason, such as prevention of the crack faces closing mid‐thickness due to the reverse plastic zone.     

Temperature control of a water bath by self-tuning PI controller

Although there have been several reports of various self-tuning proportional-plus-integral (STPI) schemes and proportional-plus-integral-plus-derivative (STPID) schemes for controllers in recent years, their theory and practice are still immature. The capabilities of this type of controller to control real physical processes need to be proven in more detail. In this light, the paper presents an application of an STPI controller proposed by Cameron and Seborg (1983) to a microcomputer-controlled water bath system. The water bath is an example of an important component in many industrial chemical processes. Experiments are conducted to test the STPI controller and to compare its performance with two other controllers, namely a self-tuning controller (STC) due to Clarke and Gawthrop (1975, 1979) and a conventional PI controller. The reliability of the STPI controller is tested by artificially adding load disturbances, simulating a change in the process dynamics, and artificially adding a variable delay element in the control loop of the process. The results prove that the performance of the STPI controller is as good as a self-tuning controller with the added advantage of having a PI-like structure. Moreover, the STPI controller performs better than the conventional PI controller, especially when there are changes in the process dynamics.     

SPROUT INHIBITION BY GAMMA IRRADIATION IN FRESH GINGER (ZINGIBER OFFICINALE ROSCOE)

ABSTRACT. A study on sprout inhibition by gamma irradiation in fresh ginger of a local variety was carried out. Fresh ginger was irradiated at the doses of 0, 25, 50 and 80 Grays (Gy) and stored at temperature 25-28°C and relative humidity ranging from 76-96% for 4 months. the parameters observed were physiological weight loss, sprouting, external appearance, fungal infection, moisture content, water activity, crude fiber content and total sugar. the results show that irradiation at the doses studied effectively inhibited sprouting in ginger when compared to the nonirradiated samples. However, radiation was unable to extend the shelf-life as all samples started to deteriorate after 2 months storage.     

EFFECT OF DIFFERENT DRYERS AND DRYING CONDITIONS ON ACCEPTABILITY AND PHYSICO-CHEMICAL CHARACTERISTICS OF DURIAN LEATHER

Optimization study on drying condition ofdurian leather was carried out using Response Surface Methodology (RSM). The optimization was conducted for two different dryers, oven dryer and forced-air cabinet dryer, with temperature and time of drying as independent variables. It was shown that both variables significantly affected most of the sensory properties. For both dryers, the optimum points for 5 sensory attributes evaluated including taste, aroma, texture, appearance and overall acceptability, were at temperatures ranged from 47–55 C for 10–14 h. Based on the overall acceptability, the optimum condition for oven-dried leather was achieved at temperature 50C for 12.6 h, while for cabinet-dried leather at 52.5C for 10 h. Results showed that panelist preferred product dried with low temperature-long time compared with high temperature-short time. Except for Hunter color b value of cabinet-dried product, results also indicated that drying condition was significantly influencing the physico-chemical properties such as moisture, A_w, nonenzymatic browning, texture, vitamin C and color of durian leather.     

OXIDATIVE STABILITY OF A LIPASE-CATALYZED TRANSESTERIFIED PALM STEARIN AND PALM KERNEL OLEIN BLEND

A palm stearin (PS) and palm kernel olein (PKO) blend at ratio 1:1 (by weight) was enzymatically transesterified. The oxidative stability of the blend, its control (without transesterification) as well as the PS and PKO were evaluated in a conventional oven at 60C for two weeks. Samples were withdrawn at 2 day intervals and analyzed for their peroxide value, iodine value, content of conjugated diene and fatty acid (FA) composition. The transesterified blend was found to be more susceptible than the control to oxidation during storage. PS exhibited the largest change in oxidative parameters employed, mainly due to its high level of unsaturated FA.     

以碳黑油墨柔印实现电子产品中细实线的印制

摘译随着印刷电子及相关材料基础研究的发展,显示器、背板、存储器、天线、电池以及其他新兴电子产品正在不断涌现。为了满足这些新兴印刷电子产品的加工需求,科研人员已经针对制造电子产品所采用的接触式和非接触式印刷方式开展了大量的研究工作。目前的研究表明,与非接触式印刷工艺相比,接