Analysis of Correlation between Concentration of Atmospheric Particulates and Humidity Based on the Aerodynamic Particle Sizer

The TSI-3321 APS was used to measure concentration of atmospheric particulates in Ranjiaba region of Yubei District in Chongqing City during March 21- 29,2014,and the temporal variations in the hourly average mass and number concentration and median particle diameter of PM10 and PM2.5 as well as their correlation with relative humidity were analyzed. The results showed that the three indicators of PM10 and PM2.5 except for the mass concentration correlated with relative humidity,of which the correlation between the mass median particle diameter and relative humidity was the best. The correlation coefficient R^2 between the mass median particle diameter of PM10（ PM2.5） and relative humidity was up to 0. 943（ 0. 832）. Therefore,relative humidity and pressure are key impact factors of indicators of particles.

Experimental and computational analysis of the coolant distribution considering the viscosity of the cutting fluid during machining with helical deep hole drills

An experimental analysis regarding the distribution of the cutting fluid is very difficult due to the inaccessibility of the contact zone within the bore hole.Therefore,suitable simulation models are necessary to evaluate new tool designs and optimize drilling processes.In this paper the coolant distribution during helical deep hole drilling is analyzed with high-speed microscopy.Micro particles are added to the cutting fluid circuit bya developed high-pressure mixing vessel.After the evaluation of suitable particle size,particle concentration and coolant pressure,a computational fluid dynamics(CFD)simulation is validated with the experimental results.The comparison shows a very good model quality with a marginal difference for the flow velocity of 1.57%between simulation and experiment.The simulation considers the kinematic viscosity of the fluid.The results show that the fluid velocity in the chip flutes is low compared to the fluid velocity at the exit of the coolant channels of the tool and drops even further between theguidechamfers.Theflow velocity and the flow pressure directly at the cutting edge decrease to such an extent that the fluid cannot generate a sufficient cooling or lubrication.With the CFD simulation a deeper understanding of the behavior and interactions of the cutting fluid is achieved.Based on these results further research activities to improve the coolant supply can be carried out with great potential to evaluate new tool geometries and optimize the machining process.

Effects of Functional Fish Organizations on the Fractal Characteristics of the Microstructure of Feces

Fish feces affect the structure and function of aquatic ecosystems,and they are affected by the functional fish organizations.In this research,Ctenopharyngodon idellus,Hypophthalmichthys molitrix,and Cyprinus carpio were selected to study the effects of different functional fish organizations on the fractal characteristics of fecal micro-structure by scanning electron microscopes(SEM),particles(pores)and cracks analysis system(PCAS).The results showed that fish feces pores mainly consisted of medium pores(cumulative pore number,97%)classified by the International Union of Pure and Applied Chemistry(IUPAC).The grain area fractal dimension D_(1) and the pore-number and pore-size fractal dimension D_(2) were 1.94-1.96 and 2.07-2.19,respectively.The distribution of fish feces pores was very close to the Sierpinski carpet structure,which is the basic fractal construction methods widely used to describe the fractal of pore surface distribution.D_(1)(1.96)and D_(2)(2.19)of Hypophthalmichthys molitrix were the maximum values of the three functional organizations.Combining with the habit of fish,it is inferred that the feces of H.molitrix,the finer the feed and the faster the swimming of fish,the higher the content of feces clay,the larger the fractal dimension of feces,the easier it is to decompose feces,and the high the content of nutrients and organic matter to release into the water.It is demined that fish functional organizations affected the fractal characteristics and the stability of fish feces in water.This study is helpful for further research on water quality prediction and the impact of functional fish organizations on the structure and function of the ecosystem.