低压处理对板栗淀粉理化特性的影响

以安徽大红袍板栗为原料,采用场扫描电镜和光学显微镜分析板栗淀粉在不同压力和料液比条件下表观形态和晶体特性的变化。结果表明:在相同的时间条件下,随着压力增大,板栗淀粉颗粒越易膨胀破裂,当压力为0.05MPa时,淀粉颗粒表面出现泡状凸起;随着淀粉体系中水分含量的升高,板栗淀粉颗粒越易膨胀破裂,料液比达到1∶1,压力为0.05MPa时,大部分淀粉颗粒破碎崩溃。溶解度试验中,不同压力、水分处理后,压力增大,板栗淀粉溶解度随之增大;压力一定,水分含量越高,溶解度越大。不同压力、水分处理后的板栗淀粉的晶体特性表明,压力不会改变板栗淀粉的晶体类型,但随着压力增大,淀粉中水分含量增大和处理时间延长,板栗淀粉晶体区面积缩小,晶体含量降低。     

浮子式波浪能转换器运行特性的试验研究

浮子式波浪能转换器是将波浪能转换为液压能或电能的主要利用形式之一,其运行特性直接影响到波浪能开发利用的可行性与有效性。本文对浮子式波浪能转换器的运行特性进行了物理试验研究,分析了不同波浪要素、非线性外负载、装置几何布置和锚固方式条件下,波浪能转换器的浮子动力响应、活塞泵出水流量和装置转换效率的变化规律。研究结果表明:固定尺寸的波浪能转换器在满足最优波频和外负载条件时可取得最大转换效率;波浪能转换器的最优几何布置形式会受到外负载的影响,大负载作用下单浮子式波浪能转化器的效率值大于其他布置方式;双浮子式波浪能转换器的锚固约束越少,转换效率越高。     

焊缝的超声波检测与有限元仿真

为了避免超声波在检测焊缝的过程中因噪声信号干扰而导致结果的错估,首先采用MUTLI软件中的超声波衍射时差法（TOFD）来检测人为的焊缝缺陷试块,得到准确的A扫图与TOFD图像;然后利用ANSYS软件模拟仿真超声波的检测过程,根据惠更斯原理建立超声波检测的有限元数值模型.将超声波的传播过程看做对试块的加载过程,从不同的节点上施加具有时间延迟的载荷,得到声压幅值图像.对比分析实验幅值图像与仿真幅值图像,两种图像的相似度很高,证实有限元仿真方法有助于超声波对焊缝的检测.从仿真的幅值图像中可以判定实验图像中的干扰信号,对检测结果的误差分析具有很大的帮助.     

Transient, three-dimensional simulation of particle dispersion in flows around a circular cylinder Re = 140-260)

To understand three-dimensional dispersion of particles in the flow around a bluff body, direct numerical simulations of particle-laden wakes of a circular cylinder with Reynolds number ranging from 140 to 260 were performed. The domain decomposition method and high-order finite-difference schemes were applied to solve the fluid flow. A Lagrangian tracking solver was developed to trace the trajectories of each particle in the non-uniform grid system. It is observed that the predicted coherent structures and vortex dislocation frequency agree well with those of previous experimental studies. Particles at low Stokes numbers follow the vortex motion and can disperse into the core regions of the vortex-street and the recirculating region. Particles at larger Stokes numbers try to maintain their own motion, but take on a non-uniform distribution in the wake due to the strong folding effect of shed vortices. But for particles at intermediate Stokes numbers, higher concentration occurs in the outer boundary regions of the vortices as well as the thin band regions connecting adjacent vortex structures. Besides the spanwise vortex structures, the streamwise vortex tubes also have a remarkable effect on particle dispersion, which results in a ‘mushroom’ shape particle distribution in the wake. Furthermore, non-uniform forcing at inlet has additional effect on particle dispersion and mixing.     

Experimental study of acoustic agglomeration of coal-fired fly ash particles at low frequencies

This paper presents an experimental study of acoustic agglomeration of coal-fired fly ash particles in travelling sound waves. The ranges of variation of the main physical parameters are as follows: acoustic frequency, f = 700-3000 Hz; sound pressure level (SPL), SPL = 130-147 dB; residence time, t = 3-7 s; aerosol number concentration, N₀ = 1.0 × 10⁵-3.7 × 10⁵ /cm³. A 68.4% decrease in total number concentration is gained under an SPL of 147 dB and a frequency of 1400 Hz. Aggregates larger than 10 µm are observed in scanning electron microscopy photographs. The results show that the effect of sound waves is very sensitive to the frequency change, which means that orthokinetic interaction governs the process. There exists an optimum frequency for a given particle size distribution, which decreases slightly as SPL increases. The influences of SPL, residence time and initial total number concentration are also studied.     

水泥企业储库容量的优化计算

大型化是水泥企业生产设备及储库发展的必然趋势,单体储量为3～5万t的各种大型均化库和物料储库应运而生.然而随着储库的大型化,建设成本上升,储库的运行费用也随之提高.储库建设的经济性,越来越受到水泥企业高度关注.     

酒糟加工饲料及相关问题的研究

通过对酒糟饲料的发展利用状况及加工技术的介绍,论述了酒糟饲料加工对我国走环保节能、可持续发展的道路的必要和重要性。同时,也探讨了酒糟饲料加工技术中尚待解决的相关问题,这对发展和推动我省的饲料加工工业乃至全国的饲料加工工业都具有积极的作用。     

Dynamic weighted random load balancing algorithm for SIP application server

essages. The weight of each server is dynamic adaptive with feedback mechanism. DWR insures that the cluster is balanced, and it performs better than the limited resource vector (LRV) algorithm and minimum sessions first (MSF) algorithm.     

金瑞广场地下室基坑支护工程实例

通过某基坑工程实践,表明大面积两层地下室软土基坑在相对开挖深度较浅且周围环境较好的条件下采用一道钢筋混凝土支撑结合排桩支护是可行的。由于仅设置一道支撑,支撑竖向位置布置比较低,因此浅部土层开挖稳定性要充分考虑。软土基坑侧向变形受施工时间影响很大,地下室施工应严格控制施工暴露时间。     

影响CK61100数控车床尾架定位精度的结构因素

根据CK61100数控车床尾架结构,提出尾架部件对工件定位精度的影响因素,并通过COSMOSWorks软件对相关因素进行分析、验证以利于优化设计的实现。