检索结果-南通市图书馆

Experimental study on the mitigation effect of mangroves during tsunami wave propagation

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2023年第7期42卷 124-137页

作者： Cheng Chen Chen Peng Hui Yan Minjian Wei Tingyu Wang College of Civil Engineering Fuzhou UniversityFuzhou 350108China

Mangroves are crucial for protecting coastal areas against extreme disasters such as tsunamis and storm *** experimental study was conducted to determine how mangroves can mitigate the tsunami wave *** test was performed in a flume, where mangrove models were installed on a slope, and dam-burst waves were used to simulate tsunami waves. To study how mangrove forests reduce the impact of tsunamis, this paper measured the heights of the incoming waves under different initial conditions(tsunami wave intensity and initial water depth) and plant factors(arrangement and distribution density) and described the reduction process. The results show that, after passing through the mangrove, the tsunami bore height will decrease within a certain range as the initial water depth increases. However, there is no correlation between the increase of inundation level and the drop of water level. The bore height attenuation is more significant at higher density of mangroves,but after tsunami passing through the mangroves, the relative bore height will decrease. When the distribution density of mangroves is constant, the wave attenuation at different locations(before, on and after the slope)shows different relationships with the initial water depth and wave height for different models. The transmission coefficient(K_(i)) shows a parabolic correlation with its density. The proportion of the energy loss caused by the mangrove resistance to the total energy(E_(b)) is defined as C_(m2). The variation trend of C_(m2) corresponds to the tsunami wave energy attenuation rate(C_(a)) and K_(i).

关键词： mangroves tsunami wave distribution density arrangement transmission coefficient

Spray Characteristics Study of Combined Trapezoid Spray Tray

在线全文

学校读者我要写书评

暂无评论

China Petroleum Processing & Petrochemical Technology 2014年第3期16卷 104-110页

作者： He Liang Li Chunli Liu Jidong Xie Zhenshan School of Chemical Engineering and Technology Hebei University of Technology

The spray behaviors of the combined trapezoid spray tray(CTST) have a significant effect on the gas-liquid interface. In this paper, the spray process of CTST in a column, 570 mm in diameter, was experimentally investigated by using a high-speed camera, and a theoretical model of the average droplet size was established according to the unstable wave theory. The results demonstrated that gas velocity passing through the hole is the key factor affecting the spray angle, which increases gradually with an increase in the gas velocity. When the gas velocity exceeds 7.5 m/s, the spray angle becomes stable at around 55°. The average flow velocity of the liquid sheet at the spray-hole increases significantly with an increase in the gas velocity, and decreases slightly with an increase in the liquid flow rate; moreover, it increases from the bottom of spray hole upward to the top. The density of liquid drops distribution in the spray area can be described by the RosinRammler function. In addition, the liquid drops are mainly concentrated in the area of spray angle ranging from 20° to 40°, and they gradually become uniform with the increase in the gas velocity and the liquid flow rate. The average liquid drop size deceases with an increase in the gas velocity, and increases slightly with an increasing liquid flow rate. In the normal working range, the average liquid drop size is about 1.0 mm to 2.5 mm in diameter.

关键词： CTST spray angle gas velocity distribution density average flow velocity of liquid sheet droplet size

Theoretical study on separation density of gravity beneficiation

在线全文

学校读者我要写书评

暂无评论

Journal of Coal Science & Engineering(China) 2010年第2期16卷 193-197页

作者： JIAO Hong-guang ZHAO Xiao-nan ZHAO Yue-min School of Materials Science and Engineering Henan Polytechnic University Jiaozuo 454003 China School of Chemical Engineering and Technology China University of Mining ＆Technology Xuzhou 221008 China

Separation density is one of the most concerned operating parameters in gravity *** equal-errors cut point or distribution density is usually used as practical separation density in gravity beneficiation, the gravity separating process complexly affected by many kinds of factors is actually carried out at a fluctuant density; namely, the practical separation density is essentially a random *** studied results show that the equal-errors cut point is the mathematical expectation of this random variable, and the distribution density corresponds to the highest separation efficiency in the gravity separation *** shows that the distribution density is the best working point of the gravity separation equipment under a particular operating ***,in order to fully develop the function of the gravity separation equipment, the distribution density should be close to the theoretical separation density unlimitedly in the range of minimum fluctuation.

关键词： separation density gravity beneficiation equal-errors cut point distribution density random variable

A FREE-BOUNDARY PROBLEM TO DYNAMIC SYSTEM FOR PURE FOREST

在线全文

学校读者我要写书评

暂无评论

Annals of Differential Equations 2010年第2期26卷 227-233页

作者： Longfeng Xu, Hanbing Wu (Anhui University of Technology, Maanshan 243002, Anhui, )

A free-boundary model of nonlinear dynamic system for pure forest is presented, in which the felling rate is unbounded nearby the free boundary. The effiect of unbounded function on a priori estimate and analysis of r... 详细信息

关键词： felling rate distribution density free boundary integral equation fixed point theorem classical solution