Response surface optimization and characteristics of rambutan (Nephelium lappaceum L.) kernel fat by hexane extraction

Response surface methodology (RSM) was used to study the effect of moisture content (1.59-18.41 g/100 g), extraction time (2.3-10.7 h) and particle size (0.09-2.11 mm) on the fat yield from rambutan kernels using hexane extraction. The physical and chemical characteristics of rambutan fat were also determined. The optimum conditions obtained from response surface analysis was 4.99 g/100 g moisture, 1.05 mm particle size and 9.2 h extraction time. Under these optimum conditions, the maximum fat yield was 37.35 g/100 g. The extracted fat was a white solid at room temperature. The physical and chemical characteristics of the extracted fat compared well with those of conventional fats. The high level of arachidic acid (∼ 34.3 g/100 g fat) and low iodine value in rambutan kernel fat permits the use of the fat, especially where oxidation may be a concern, without its being subjected to hydrogenation.     

Learning low-rank Mercer kernels with fast-decaying spectrum

Low-rank representations have received a lot of interest in the application of kernel-based methods. However, these methods made an assumption that the spectrum of the Gaussian or polynomial kernels decays rapidly. This is not always true and its violation may result in performance degradation. In this paper, we propose an effective technique for learning low-rank Mercer kernels (LMK) with fast-decaying spectrum. What distinguishes our kernels from other classical kernels (Gaussian and polynomial kernels) is that the proposed always yields low-rank Gram matrices whose spectrum decays rapidly, no matter what distribution the data are. Furthermore, the LMK can control the decay rate. Thus, our kernels can prevent performance degradation while using the low-rank approximations. Our algorithm has favorable in scalability—it is linear in the number of data points and quadratic in the rank of the Gram matrix. Empirical results demonstrate that the proposed method learns fast-decaying spectrum and significantly improves the performance.     

以轨道交通支持天津市城市空间结构转化——天津市市域轨道交通系统规划

交通系统与城市空间结构是相互联系、相互推动的关系。轨道交通作为现代化、快速、大运量的客运系统,对城市空间演变发挥着重要作用。随着城市的快速发展,天津市的空间布局面临着重大转变。天津的市域轨道交通系统规划,以城市空间发展战略为依托,以积极引导天津市空间结构转化为目标,规划构建包括市域线及城区线两级线网、全市域联网互动的轨道交通网络。     

Fatty acid accumulation in the different fractions of the developing corn kernel

In the food industry, the use of the oil is determined by the composition of fatty acids, and this is highly dependent on its natural origin. The fatty acid composition of whole corn kernel was determined in three varieties of corn (Astro, GH2547, and Local). Linoleic acid was the predominant fatty acid in the oil of Astro and Local at all collection dates, whereas it was the major fatty acid in the oil of GH2547 only between 40 and 60 days after pollination (DAP). The fatty acid accumulation in the endosperm, pericarp and germ fractions of the corn kernel during maturation was determined. The accumulation pattern of oil content was different in these three kernel fractions. The highest levels of oil content in the endosperm (2.2%), germ (34.3%) and pericarp (10.8%) fractions were detected at 20, 40 and 30 (DAP), respectively. The fatty acid accumulation patterns were different amongst the analysed kernel parts, indicating a numerous differences between the three corn kernel parts. Throughout the sampling periods, the endosperm fraction was distinguished by the highest and the lowest levels of oleic and linoleic acids, respectively. At all stages of kernel development, the pericarp fraction had the highest levels of total polyunsaturated fatty acids, which has numerous healthy applications. These results may be useful in the understanding of the potential source of the beneficial unsaturated fatty acids amongst the different fractions of the corn kernel during maturation.     

基于边缘与区域特征的无人机图像地平线检测

针对基于视觉的无人机自动定姿中的地平线检测问题,分析了图像中地平线的边缘特征和区域特征,提出了基于单向边缘和灰度分布特征的地平线归属点识别准则和检测方法,利用改进的多模型输出RANSAC估计算法实现了边界点中候选地平线提取,最后利用地平线的识别准则完成了地平线的快速、可靠鲁棒性检测.实验结果证明了该算法的有效性.     

Melt Rheological Behavior and Thermal Properties of Low-Density Polyethylene/Palm Kernel Shell Composites: Effect of Polyethylene Acrylic Acid

The melt flow behavior and thermal properties of low-density polyethylene (LDPE)/palm kernel shell (PKS) composites were studied. Polyethylene acrylic acid (PEAA) was used as a compatibilizer in the composites. The results showed that the increasing of PKS loading had decreased MFI values of LDPE/PKS composites. The presence of PEAA increased the MFI values of the LDPE/PKS composites. The apparent viscosity of the composites was found to exhibit a linear relationship with the reciprocal of the temperature. Thermal properties showed that higher filler loading tended to reduce the onset temperature as the PKS possessed lower degradation temperature compared to the LDPE. The presence of the PKS in the LDPE polymeric matrix improved the thermal stability of the composites. The addition of PEAA into the composites provided better interfacial bonding between the LDPE matrix and PKS filler, while higher onset temperature and lower total weight loss were observed of LDPE/PKS composites. The activation energy of the LDPE/PKS composites was increased with increasing filler loading. At similar filler loading, the presence of PEAA increased the activation energy of the LDPE/PKS composites.     

油条制作的工艺研究

油条是我国传统早餐主食之一,深受食客们青睐。油条成品色泽金黄,外酥脆内细软,咸香适口,成为老少皆宜、妇幼喜食的大众化传统早点食品。本文阐述了油条制作工艺过程及其研究,通过对几种油条制作方法的比较,获得色泽、口感、内部结构和香气等指标都达到较高标准、人们可以放心食用的健康油条。     

区域推广应用TRIZ理论效果评价指标体系研究

全面系统地反映区域推广应用TRIZ理论的效果,建立一套客观且实用的评价指标体系,关系到TRIZ理论推广应用的深度和广度.在系统分析区域推广应用TRIZ理论影响因素的基础上,从推广效果和应用效果两个方面构建了推广应用TRIZ理论效果评价指标体系,给出指标体系的应用策略.旨在为区域科技管理部门准确了解和掌握TRIZ理论推广应用情况以及制定相关政策提供科学依据.     

Effect of sodium carbonate on appearance and textural properties of glutinous rice cake

The effect of sodium carbonate (Na₂CO₃) on the appearance and textural properties of glutinous rice cake was investigated. Glutinous rice kernels were soaked in Na₂CO₃ solution (0–1.2 N) at 25 °C for 24 h. Soaked rice was used for glutinous rice cake (GRC) production. The results showed that the rice soaked in Na₂CO₃ had lower protein and fat content, but higher ash content than those of untreated rice, while the amylose content in treated and untreated rice was not significantly different. Moreover, images from scanning electron microscopy showed that the starch granules from rice treated with Na₂CO₃ had smoother surfaces than untreated ones. From the alkali digestion test, the rice kernels treated with Na₂CO₃ suggest a lower gelatinization temperature than untreated rice. The GRC was uniform, and yellow colour was enhanced. Moreover, GRC exhibited an increase in softness and stickiness with increasing Na₂CO₃ concentration.