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1.
《Journal of food engineering》1986,5(4):321-333
Water sorption and flow properties of whole egg powder with and without flow conditioners were studied. Flow conditioner silica and sodium silico-aluminate improved the egg powder's flowability due to particle surface modification. Addition of the conditioners appears to eliminate the hysteresis loop. Moisture uptake by powders with flow conditioners was greater than by those without. 相似文献
2.
作为一种高效、安全的气泡发生装置,文丘里式气泡发生器在工业、化工等过程有广泛的应用,但对其内部气泡破碎过程和作用机制相关研究较少。前期研究发现,较大气泡进入文丘里管扩张段后会发生迅速减速,并对气泡碎化过程产生极大影响。基于大涡模拟方法,对文丘里式气泡发生器内的流动过程进行了数值模拟,发现在扩张段近壁面存在明显的涡流区,涡流区前端与上游来流发生强烈的碰撞,造成进入此区域的流体发生迅速减速,使得涡流区与主流交汇区附近静压急速增大;当此区域存在运动的气泡时,激增的压力梯度力以及附加质量力导致气泡运动速度迅速减小,并与周边流体形成了更强的相互作用;高流速条件下,会使气泡发生严重变形、甚至破碎。 相似文献
3.
The simulation of crack propagation processes in rock engineering has been not only a research hot spot among scholars but also a challenge. Based on this background, a new numerical method named improved kernel of smoothed particle hydrodynamics(IKSPH) has been put forward. By improving the kernel function in the traditional smoothed particle hydrodynamics(SPH) method, the brittle fracture characteristics of the base particles are realized. The particle domain searching method(PDSM) has also been put forward to generate the arbitrary complex fissure networks. Three numerical examples are analyzed to validate the efficiency of IKSPH and PDSM, which can correctly reveal the morphology of wing crack and the laws of crack coalescence compared with previous experimental and numerical studies.Finally, a rock slope model with complex joints is numerically simulated and the progressive failure processes are exhibited, which indicates that the IKSPH method can be well applied to rock mechanics engineering. The research results showed that IKSPH method reduces the programming difficulties and avoids the traditional grid distortion, which can provide some references for the application of IKSPH to rock mechanics engineering and the understanding of rock fracture mechanisms. 相似文献
4.
Ultrasonic fracturing(UF) can be used to form crack networks for oil or gas in the mining industry and hard rock excavation. In this paper, the three-dimensional internal laser-engraved crack method(3D-ILC) is introduced to make penny-shaped internal crack within the samples without any damage to the surfaces. Physical experiments were performed on the transparent samples with internal cracks at different depths. The macro-and micro-fracture fractography characteristics were focused on and analy... 相似文献
5.
我国水电蕴藏量居世界首位。近年来水电事业发展迅速,中小型水电项目的经济效益是投资者最为关注的内容,是影响投资者决策的首要因素。本文根据大庄水电站实际年运行费与设计阶段的经营成本对比,分析了经营成本变化的原因以及对项目经济效益的影响。分析结果显示,项目FIRR低于原设计标准,但高于新的财务基准收益率,项目连续亏损尚有其他原因,应做进一步分析。同时提出对经营成本与营业成本两个概念进行理论研究的建议。 相似文献
6.
《Journal of Great Lakes research》2020,46(6):1511-1520
Lake changes have great impacts on local and regional ecosystems and socioeconomic activities. To determine the recent changes in Hongze Lake, radar altimeter and Landsat data were used to examine the water level and area and estimate the water volume changes from 2003 to 2018. Generally, the annual water level results from radar altimeter data showed good agreement with in situ measurements (r2 = 0.62, bias = −0.02 m, mean absolute error = 0.10 m and root mean square error = 0.12 m). Although the results show that the water level and water volume of Hongze Lake had no trends during the 16 years, the water area decreased significantly at a rate of 19.76 km2 per year. Despite great fluctuations throughout 16 years, two shifts occurred in approximately 2007 and 2013. The water level, area and volume of Hongze Lake decreased from 2007 to 2012, but they all showed increasing trends after 2013. The interannual changes in the water level and volume of Hongze Lake were consistent with the changes in annual precipitation, while the change in area was mainly affected by human activities, especially land reclamation and aquaculture activities along the lakeshore. In addition, the intra-annual change in the water level was greatly affected by artificial activities such as irrigation and flood prevention. 相似文献
7.
针对取自三峡库区范家坪滑坡砂岩,采用室内模拟高温季节环境条件,研究砂岩在“烘干-吸水”循环作用下的热湿效应,包括砂岩的质量劣化和抗剪强度参数的变化。结果表明①经历“烘干-吸水”热湿循环作用后,岩石质量劣化速率和吸水率是非线性波动变化的,其波动特征体现出了岩石内部裂隙的动态发育;②砂岩的抗剪强度参数黏聚力c和内摩擦角φ随着“烘干-吸水”热湿循环次数的增加而不断降低,在循环初期参数折减幅度较大,后期变缓并逐渐趋于稳定,这与岩石质量劣化规律具有相似性;③提出通过岩石直剪破坏裂纹延伸角度,定性判断岩石强度的方法。研究成果对昼夜温差大且气候潮湿的华中地区岩石劣化预测具有实际意义。 相似文献
8.
An Impact Assessment Method of Dam/Sluice on Instream Ecosystem and its Application to the Bengbu Sluice of China 总被引:1,自引:0,他引:1
C. S. Zhao C. L. Sun J. Xia X. P. Hao G. F. Li K. Rebensburg C. M. Liu 《Water Resources Management》2010,24(15):4551-4565
A method is presented for impact evaluation of dams/sluices on their downstream aquatic ecosystems in the absence of detailed long-sequence ecology ecosystem data. It is based on the analysis of relations between indices of water quality and aquatic organisms. It can be applied to a river section absent of long-sequence ecology ecosystem data. For this study it was used to evaluate the effects of the Bengbu Sluice (BS), a typical sluice in the Huai River in China. Results indicate that in April and May the impact of BS on different downstream aquatic organisms varied. The most significant impact was on phytoplankton, with 91.7% of phytoplankton indices showing a 100% increase in quantity and biomass. The second most significant was on zooplankton, with 60.0% of zooplankton showing greater increase in quantity and biomass. The least significant impact was on zoobenthos, with only 33.3% showing greater increase in quantity and biomass. Most of these organisms have higher pollution-resistibility. These findings suggest that the present operation scheme will gradually lead to biodiversity decrease in the downstream aquatic ecology system, which will harm the instream aquatic ecology. Overall, BS has a negative impact on the downstream aquatic ecology system. It is argued that, in order to reduce the negative impact on the downstream aquatic ecology system, the operation of BS needs to be improved so that the discharge into the downstream river course is increased. Data comparison of the aquatic ecosystem condition between 1982 and 2006 also demonstrates the decreasing aquatic ecosystem quality downstream of BS. 相似文献
9.
LIANG Wenquan HE Zhen ZHANG Yongchuan CHEN Meizhu YANG Huaquan 《武汉理工大学学报(材料科学英文版)》2006,21(4):158-162
1 IntroductionPozzolanic capacity of mineral admixture in concreteis usually tested by direct reaction with Ca(OH)2whilemonitoringthe consumption of lime (or strength develop-ment) .In theory,it is possible to completely react withall the calcium hydroxide , but this happens in practiceinfrequently.Some standards for methods ,among whichthere are chemical analysis and physical tests ,are devel-opedin some countries to allowaccurate characterizationof pozzolanic materials[1-3].And crrently,th… 相似文献
10.