Roasting-Related Changes in Oxidative Stability and Antioxidant Capacity of Apricot Kernel Oil

Apricot kernels were roasted for various lengths of time (0–30 min) at 180 °C and changes in the oxidative stability, antioxidant capacity, color, as well as the level of tocopherols and fatty acids of the apricot kernel oil (AKO) were monitored. While the level of tocopherols decreased, the oxidative stability and antioxidant capacity of AKO increased with roasting, probably due to the formation of antioxidative Maillard reaction products (MRPs) during the roasting. Medium roasted samples (15–20 min) were found to be more resistant to oxidative deterioration. The oil from the 30-min roasted sample was more susceptible to oxidation compared to the oil from the 20-min roasted sample in most of the stability tests. Relatively shorter roasting periods (5–10 min) also led to a decrease in oxidative stability in comparison to the unroasted sample. Brownish color and antiradical activity increased with roasting and the highest values were measured in the 30 min roasted sample.     

用小直径空心纤维薄膜分流过滤葡萄酒

介绍了当今世界上葡萄酒生产过程中，对过滤工序的要求。采用小直径空心纤维薄膜的分流过滤法具有很多优点，在德国占据了很大的市场份额，将在欧洲市场上快速发展起来，具有光明的前景。     

The effect of solar radiation on the flavonol content in broccoli inflorescence

The effect of solar radiation on the quercetin and kaempferol contents in the inflorescence of three broccoli cultivars (‘Lord’, ‘Marathon’ and ‘Fiesta’) was investigated from 1999 to 2001. Great differences in the contents of both flavonols, dependent on growing time and cultivar, were found. Quercetin and kaempferol contents varied from 14.3 to 81.0 mg kg⁻¹ f.w. and from 35.9 to 213 mg kg⁻¹ f.w., respectively. Inflorescences of the cultivar ‘Lord’ were characterised by the highest mean content of quercetin and those of cultivar ‘Fiesta’ of kaempferol. The contents of both flavonols were highly positively correlated with total solar radiation in the period from planting to the harvest of broccoli inflorescences.     

Elastic-plastic thermal stress analysis of an aluminum composite disc under parabolic thermal load distribution

An elastic-plastic thermal stress analysis was carried out on an orthotropic aluminum metal matrix composite disc with a hole by using an analytical solution. The thermal load distribution was chosen to vary parabolically from inner surface to outer surface. An aluminum composite disc reinforced curvilinearly by steel fibers was produced under hydraulic press. The mechanical properties of the composite disc were obtained from experiments by using strain gauges. A computer program was developed to calculate the thermal stresses under a parabolic temperature from inner surface to outer surface. The material was assumed to be non-linear hardening. The elastic-plastic solution was performed for the plastic region expanded around the inner surface by an analytical method. The magnitude of the tangential stress component for elastic and elastic-plastic was higher than the magnitude of the radial stress component. Besides, the tangential stress component was compressive on the inner surface and tensile on the outer surface. The magnitude of the tangential residual stress component was the highest on the inner surface of the composite disc. The plastic region began at the inner surface of disc. This paper was recommended for publication in revised form by Associate Editor Joo Ho Choi Gürkan Altan is a Research Assistant of Mechanical Engineering at the University of Pamukkale, Denizli, Turkey. Gürkan Altan received the B.E. degree (1999) in mechanical engineering from Dokuz Eylül University, Izmir, and the M.S. degree (2004) in mechanical engineering from Pamukkale University, Denizli. Gürkan Altan is interested in production and applications of composite materials. Currently he is involved in the development and application of joints of composite structures.     

Fracture properties of spray-dried powder compacts: Effect of granule size

Inappropriate mechanical properties of spray-dried powder compacts lead to significant green product losses, entailing considerable costs in ceramic tile manufacture as well as serious environmental problems. In addition, green strength can be indicative of how well a ceramic processing system is working.In this study, granules were prepared by spray drying a red clay slurry used in floor tile manufacture. The resulting granules were characterised and their porosity, morphology, and mechanical behaviour were determined.The study analyses the fracture properties of green ceramic materials using Linear Elastic Fracture Mechanics (LEFM), which has been widely used for fired materials, but whose application to green compacts has drawn much less attention. Two types of tests for determining fracture parameters (fracture toughness, fracture energy, and crack size) in green materials are also critically examined. Finally, the fracture parameters have been correlated to the microstructural characteristics of the compacts, in particular to granule size and the topography of the fracture.     

Sediment phosphorus characteristics in the clearwater state of Lake Mogan, Turkey

This study examined the vertical distributions of total phosphorus (TP) and phosphorus fractions, and the iron and organic matter, in the littoral sediment in a macrophyte‐dominated, clearwater state in Lake Mogan between September 2005 and August 2006. Benthic macroinvertebrates and total bacteria in the sediment also were determined. No clear seasonal or depth‐related (0–20 cm) patterns were found in sediment concentrations for the measured parameters. The phosphorus release was quantitatively very low, and a negative phosphorus release (–0.132 µg m^?2 day^?1) was measured during the summer months. The TP concentrations of the sediment samples ranged between 675.00 and 1463.80 µg g^?1 dry weight (DW), and the trophic level of the lake was eutrophic. On average, inorganic phosphorus fractions comprised the largest fraction (63%), while organic‐bound phosphorus (Org ≈ P) constituted 37% of the TP in Lake Mogan. The most important phosphorus‐immobilizing factors are high iron content (14 200–47 750 µg g^?1 DW), the sediment's clay content (47.80–51.80%), and an abundance of macrophytes at the sampling station. The low abundance of benthic macroinvertebrates (510–850 individuals m^?2), which depend on sediments with high iron and low organic matter (5.42–13.30%), played a role in the sediment phosphorus retention. Although bacterial abundance in the surficial sediment appeared to be positively correlated to temperature, the overlying water did not experience anoxic conditions, supporting a state in which bacteria were able to retain phosphorus in their cell structures. Long‐term changes in the sediments of Lake Mogan must be monitored lake. In order to optimize the management of the lake, and to determine the longevity of a clearwater state following management measures and continued external phosphorus loading, long‐term changes in the sediments of Lake Morgan must be monitored.     

Hydrolysis of pumpkin oil cake protein isolate and free radical scavenging activity of hydrolysates: Influence of temperature,enzyme/substrate ratio and time

The effect of hydrolysis parameters (temperature, initial enzyme/substrate ratio and time) on the hydrolysis of pumpkin oil cake protein isolate (PuOC PI) with acid protease from Aspergillus niger and the antioxidant potency of the obtained hydrolysates were studied by response surface methodology (RSM). The hydrolysis progress, measured by the degree of hydrolysis (DH), was described by a second-order polynomial model (R² = 0.77) and the conditions for optimum DH (42.94%) were found at temperature of 40 °C, enzyme/substrate ratio (E/S) 4.38 HUT/mg of substrate proteins and 85 min. The antiradical activity (AA) of the PuOC PI hydrolysates was examined by the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay; all hydrolysates showed a concentration dependent scavenging activity against DPPH radicals. The AA of hydrolysates was influenced by process parameters and was presented also by a second-order polynomial model (R² = 0.7). The conditions to achieve the highest DH did not result hydrolysates with the optimum AA; the highest AA ranged from 34% to 40% and were found in hydrolysates obtained at 50 °C.     

Chemical oxidation of residual carbon from ZnAl2O4 powders prepared by combustion synthesis

The removal of carbon residue from ZnAl₂O₄ nanopowders by annealing at 500–800 °C leads to a decrease of specific surface area from 228.1 m²/g to 47.6 m²/g. At the same time, the average crystallite size increased from 5.1 nm to 14.9 nm. In order to overcome these drawbacks, a new solution for removing the carbon residue has been suggested: chemical oxidation using hydrogen peroxide. In terms of carbon removal, a H₂O₂ treatment for 8 h at 107 °C proved to be equivalent to a heat treatment of 1 h at 600 °C. The benefits of chemical oxidation over thermal oxidation were obvious. The specific surface area was much larger (188.1 m²/g) in the case of the powder treated with H₂O₂. The average crystallite size (5.8 nm) of ZnAl₂O₄ powder treated with H₂O₂ was smaller than the crystallite size (8.2 nm) of the ZnAl₂O₄ powder annealed at 600 °C.     

一种新型无芯PCB 平面电感器研究

本文主要介绍了在印制板上制作无芯电感的方法，分析了其结构和性能，并采用数值计算方法建立了平面电感计算模型，为设计电感提供了一条切实可行的途径。采用现代化的印制板技术，可以精确地控制电感器的绕线宽度、线间距，克服了机器绕线一致性差的缺点，并使电感从三维向两维发展，为器件的表面贴装打下了基础。