Thermal Conductivity of Gelatinized Starches

The thermal conductivity (k) of gelatinized high-amylose and high-amylopectin starches was determined, using the heated probe method. The granular starches, mixed with distilled water at 1 to 4 kg water/ kg dry solids, were gelatinized at 120°C. Similar k values which varied from 0.434 to 0.548 W/mK in the temperature range 30 to 70°C were obtained for both starch gels. Experimental data were fitted to six structural models, representing various geometries for mixtures of water and dry starch. The perpendicular model, based on heat conduction in series through layers of dry starch and water, yielded best correlations. The predicted thermal conductivity of dry gelatinized starch (k_s) increased linearly with temperature T (K) according to the equation:      

眼镜遮挡下的正面人脸识别

针对眼镜遮档对人脸识别影响较大这一问题,提出一种从正面人脸图像中提取并摘除眼镜的方法。首先利用主成分分析和独立成分分析法对输入的戴眼镜人脸进行重建,对比重建人脸和输入人脸,从而提取眼镜遮档区域;然后经过迭代误差补偿合成相应的无眼镜人脸;最后考虑到合成图像的特殊性,使用改进的特征加权方法实现人脸识别。实验结果表明,利用提出的人脸重建和特征加权方法进行戴眼镜人脸识别,正确率可以达到91%,优于传统方法。     

HEAT TRANSFER IN MULTIPHASE CONTACTORS

A procedure for the prediction of wall-bed heat transfer coefficient for bubble columns and gas-solid fluidized beds is developed on the basis of hydrodynamic behavior of these contactors. A comparison between the predicted and experimental values of heat transfer coefficient over a wide range of design and operating variables is presented. An attempt is made to analyze the occurrence of maxima in heat transfer coefficient with respect to gas velocity in the case of fluidized beds. A procedure for the calculation of the optimum superficial gas velocity is outlined.     

NUMERICAL SIMULATION OF AN OSCILLATING FLOW PAST A CIRCULAR CYLINDER IN THE VICINITY OF A PLANE WALL

Oscillating flow around a circular cylinder in the vicinity of a plane wall was investigated by solving the two-dimensional incompressible Navier-Stokes equations with a finite element Galarkin residual method. The effect of the gap G/D between the cylinder surface and the wall on the flow behavior was studied. For the case of G/D 〈 0.25, the periodicity in the flow is attributed to both the outer shear layer instability and the oscillating frequency. As G/D 〉 0.25, vortex shedding occurs and the periodicity in the flow is mainly due to the competition of the oscillating frcqucncy and the vortex shedding frequency from an isolated stationary cylinder.     

Rennet Effects and Partitioning of Bacterial Cultures During Quarg Cheese Manufacture

Quarg was prepared with or without milk heating or rennet addition using yogurt, acidophilus, and buttermilk cultures. Total solids and protein contents in the quarg cheeses were 17.4-34.7% and 7.4-15.0%, respectively, depending on process conditions. Rennet addition increased the total solids content, especially when unheated milk was used; however, the corrected (18% T.S.) yield was unaffected. Yogurt culture resulted in the shortest incubation time (3.8-4.6 hr), while the acidophilus culture alone was unsuitable. After whey separation, the concentration of bacteria from all three cultures were higher in the quarg (8.48-9.05 log CFU/g) than in the whey (5.92-7.90 log CFU/ g) using either centrifuge or gravity filtration methods.     

Kinetics of Solids Leaching During Rehydration of Particulate Dry Vegetables

ABSTRACT: Air-dried and freeze-dried carrots were rehydrated in a computerized mixing system, and the medium was analyzed for sugar content with high-performance liquid chromatography (HPLC) and for total organic carbon (TOC). Leaching of solids was significant at very short rehydration time. Understanding the mechanism of the leaching process could provide information required for simulation. TOC values were significantly higher than those derived by HPLC, indicating that other organic components were extracted. The difference between TOC and HPLC values varied with time, indicating the existence of a different mass transfer rate. Sugars and TOC values followed an exponential behavior. Quantifying solids leaching is important for modeling and simulation of the rehydration process and for product optimization.     

Amplification and noise in high-pressure scanning electron microscopy

High-pressure scanning electron microscopy (HPSEM) is a promising new family of techniques. The present knowledge of these techniques is reviewed and a new set of criteria developed for optimizing signal detection in HPSEM with a view to preserving specimen integrity. For this purpose, amplification of contrast signals generated in HPSEM was examined by computing the effect of ionization over a range of pressures and biasing fields, routinely used for this technique. The influence of secondary ionization due to ion impact was included in the calculations. To check the calculated results, the experiments were performed in the HPSEM apparatus in a nitrogen atmosphere. A divergence between the experimental values and the calculated values was found. This was removed by taking into account the effect of recombination of charge carriers. Inductive currents generated in the HPSEM environment are transient and do not affect the conclusions of this study. The gas pressure, biasing fields and beam current for preserving specimen integrity and obtaining good micrographs were selected from the data. Experimental measurements of noise are reported, and criteria for optimizing the signal-to-noise ratio for performing HPSEM are discussed. The application of these criteria has shown that specimen current detection can be more advantageous than other methods and configurations of detection and was capable of obtaining high/medium-resolution micrographs.     

通信人工智能的下一个十年

移动通信技术走过了37年的发展历程,人工智能技术也已走过了64年的发展历程。从早期的各自独立演进,到5G与人工智能开始深度融合发展,“5G与人工智能”已被业界视为一组最新的通用目的技术组合,对垂直行业的发展起到提振生产力与赋能的作用。首先介绍了早期移动通信和人工智能各自的发展路线,并重点回顾了人工智能与通信技术在3G到5G阶段开始融合发展。针对通信人工智能,详细阐述了当前人工智能技术在移动通信生态系统中各领域的发展情况,包括通信网络基础设施、网络管理与运营、电信业务管理、跨领域融合智能化、垂直行业与专网等,并总结了通信国际标准组织对人工智能技术在移动通信系统中的分级定义与演进路线。面向下一个十年,展望了通信人工智能未来的发展路线与演进趋势,并结合3GPP与ITU-R的5G/6G时间表,前瞻性探索了基于3GPP和O-RAN路线的网络智能化、基于体验感知与意图的网络管理与运营系统的发展、网络AI信令体系、面向智慧中台演进的电信业务与支撑体系、跨领域融合的智能化体验管理与策略管理、从SLA向ELA的演进以及面向垂直行业的智能专网等。最后建议行业达成共识,在下一个十年中全面加速推进人工智能在通信生态领域的发展。     

EXACT DYNAMIC STIFFNESS MATRIX FOR BEAMS OF ARBITRARILY VARYING CROSS SECTIONS

In this paper, the exact dynamic stiffness matrix is derived for the transverse vibration of beams whose cross-sectional area and moment of inertia vary in accordance to any two arbitrary real-number powers. This variation represents a very large class of arbitrary varying beams and thus, fills the void currently existing in this area of research. With this approach, most beams can be modelled by just one element, and for beams having abrupt profile changes or with very complex profiles, they can be divided into separate distinct parts, with each of the part modelled by just one element, and then assembled together. The method is exact; however, the accuracy of the results depends only on the solver used to solve the exact frequency equation. To demonstrate the procedure, beams of non-linearly varying circular and elliptical cross-sections, and a combination beam consisting of a linear-tapered section, a uniform section and a non-linearly varying-section are analysed for their natural frequencies. Since there are no known solutions for these structures, comparison with finite element results was made and very good agreement was observed. © 1997 by John Wiley & Sons, Ltd.