Synthesis of Nanometer Cobalt Blue Pigment by Microemulsion Method and Control of Diameter of Particle

The nanometer cobalt blue pigments were prepared by microemulsion method. Using dynamic light scattering(DLS) test method, the influences of water content on the size of liquid drop of microemulsion and the liquid drop of microemulsion on the final diameter of nanometer particle were studied in the course of preparation. Accordingly, the method to control the diameter of nanometer particle by changing water content was established. The nanometer cobalt blue particles were confirmed by XRD and TEM. Color parameters of pigments were determined. The quantum size effect of the pigments was discussed.

Experimental determination of distributions of soot particle diameter and number density by emission and scattering techniques

A diagnostics method was presented that uses emission and scattering techniques to simultaneously determine the distributions of soot particle diameter and number density in hydrocarbon flames. Two manta G-504 C cameras were utilized for the scattering measurement, with consideration of the attenuation effect in the flames according to corresponding absorption coefficients. Distributions of soot particle diameter and number density were simultaneously determined using the measured scattering coefficients and absorption coefficients under multiple wavelengths already measured with a SOC701 V hyper-spectral imaging device, according to the Mie scattering theory. A flame was produced using an axisymmetric laminar diffusion flame burner with 194 mL/min ethylene and 284 L/min air, and distributions of particle diameter and number density for the flame were presented. Consequently, the distributions of soot volume fraction were calculated using these two parameters as well, which were in good agreement with the results calculated according to the Rayleigh approximation,demonstrating that the proposed diagnostic method is capable of simultaneous determination of the distributions of soot particle diameter and number density.

Influence of Self-excited Vibrating Cavity Structure on Droplet Diameter Characteristics of Twin-fluid Nozzle

It is a great challenge to find effective atomizing technology for reducing industrial pollution; the twin-fluid atomizing nozzle has drawn great attention in this field recently. Current studies on twin-fluid nozzles mainly focus on droplet breakup and single droplet characteristics. Research relating to the influences of structural parameters on the droplet diameter characteristics in the flow field is scarcely available. In this paper, the influence of a self-excited vibrating cavity structure on droplet diameter characteristics was investigated. Twin-fluid atomizing tests were performed by a self-built open atomizing test bench, which was based on a phase Doppler particle analyzer(PDPA). The atomizing flow field of the twin-fluid nozzle with a self-excited vibrating cavity and its absence were tested and analyzed. Then the atomizing flow field of the twin-fluid nozzle with different self-excited vibrating cavity structures was investigated.The experimental results show that the structural parameters of the self-excited vibrating cavity had a great effect on the breakup of large droplets. The Sauter mean diameter(SMD) increased with the increase of orifice diameter or orifice depth. Moreover, a smaller orifice diameter or orifice depth was beneficial to enhancing the turbulence around the outlet of nozzle and decreasing the SMD. The atomizing performance was better when the orifice diameter was2.0 mm or the orifice depth was 1.5 mm. Furthermore, the SMD increased first and then decreased with the increase of the distance between the nozzle outlet and self-excited vibrating cavity, and the SMD of more than half the atomizing flow field was under 35 μm when the distance was 5.0 mm. In addition, with the increase of axial and radial distance from the nozzle outlet, the SMD and arithmetic mean diameter(AMD) tend to increase. The research results provide some design parameters for the twin-fluid nozzle, and the experimental results could serve as a beneficial supplement to the twin-fluid nozzle study.

The Growth of Latex Particles during the VAc/BA Copolymerization

The semi-continuous seeded emulsion eopolymerization of vinyl acetate and butyl acrylate was carried out with hydroxyethyl cellulose as a colloid stabilizer. The morphology of the latex particle and the relationship between the reaction time and the average particle diameter and/or the conversion ratio during the polymerization were invstiguted. The experimental results shaw that the morphology of the latex particle possesses the stable sterie construction. In the seeded polymerizution, the average particle diameter of latex decreased while the conversion ratio increased. At the second term of the emulsion copolymerization （the growth stage of particle size）, the latex particle average diameter increased with copolymerization continuously, but the instantaneous conversation ratio was not large, so it was very necessaO to properly prolong the time during the holding temperature stage.

Particle Size and Shape of On-road Suspended Coarse Dust in the Shijiazhuang City, China

The particle size and shape measured by image analysis is helpful to discuss the human health effects of particulate beside the aerodynamic scale. To explore the size and shape features of particle suspended in the road environment, this research selected 12 bus stations as the sampling sites along the main road in the air polluted city Shijiazhuang, China, where a Car-Free Campaign had been carried out. We hung 2 slides covered with a layer of petroleum jelly to collect suspending particles for 24 hours at each sampling site, and measured the particles size and shape parameters with the Particle Size Analyzer of CIS-50. The results show that the average particle size by the equivalent area diameter is around 10 μm, the size distributions are multi-modal with wide span, demonstrating that coarse dust suspended on road derived from several particle sources. Most of the particles suspended are square or square-like in shape with rugged border. Compared the samples of ordinary days and of the Car-Free day, the size and shape features vary little, inferring the ineffective results for the particle control of the Campaign. There is certain relationship between particle size and shape. The number percent of PMs-E （particulate matter with equivalent area diameter beneath 5 pro） is positively correlative with the number percent of particles of square or square-like shape, and negatively correlative with that of round or round-like shape. This relationship pattern in the road environment is contrary to the situations in the upper atmosphere, inferring different transportation and source emission mechanism influences.

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.

沥青质颗粒在垂直井筒中的运移特征流速

为防止沥青质沉积堵塞油井,需明确垂直井筒内流体携沥青质颗粒运移特性。通过静态沉降试验探究不规则形状沥青质颗粒沉降末速规律,采用垂直井筒液携固流动试验装置研究不同因素对沥青质运移临界流速的影响程度,建立沥青质颗粒沉降末速和运移临界流速计算公式。结果表明:沥青质表面不均匀性增大了沉降阻力,使沉降等效直径小于颗粒实测粒径;运移临界流速与颗粒粒径成正比、与液相黏度成反比,颗粒体积分数对运移临界流速影响较小;相同条件下流体携沥青质运移临界流速为沉降末速的1.182倍。

重力参数对非阻塞性颗粒阻尼减振特性的影响

针对非阻塞性颗粒阻尼(Non-obstructive Particle Damping,NOPD)在微重力、超重及离心等非常态环境中减振效果较差的问题,采用重力加速度表征这些非常态物理环境,利用离散元法(Discrete Element Method,DEM)研究重力参数对NOPD减振特性的影响,同时还分析NOPD最优填充比及最优粒径比等结构参数在不同重力条件下的变化规律。研究表明,重力加速度在0.7~1.0 g之间时NOPD减振效果最好。在微重力环境下,当重力参数变化时,NOPD最优填充比为0.85,最优粒径比为0.45。而当重力加速度大于1 g时,NOPD最优填充比及最优粒径比均随重力加速度的增加而减小,且其最优范围也均有所扩大。

氢氧化铝低温焙烧技术研究

氢氧化铝焙烧是氧化铝生产中最后一道工序,能耗约占整个氧化铝厂能源消耗的30%左右,如何降低单位产品能源消耗对于降低运营成本和减少碳及其他污染物排放意义重大。本文通过对气态悬浮焙烧炉理论和现场应用情况的研究分析,重点研究了灼减(LOI)、失重率、颗粒直径、停留时间等与焙烧温度的关系,提出了在气态悬浮焙烧的基础上进一步降低焙烧温度,进而降低单位产品能耗,减少二氧化碳和氮氧化物排放的新型低温焙烧技术。

基于图像分析的掘进工作面粉尘颗粒检测方法

基于光散射原理测定粉尘质量浓度只能定时定点手动检测,实时性差,且只能检测出粉尘质量浓度,并不能给出粒径分布范围。目前基于图像分析的粉尘颗粒检测研究主要是针对粉尘质量浓度或粒径分布进行单方面研究,并不能实现粉尘质量浓度和粒径分布范围的同时检测。针对上述问题,提出了一种基于图像分析的掘进工作面粉尘颗粒检测方法,探究图像特征与粉尘质量浓度、粒径分布间的关系。通过粉尘样本收集及图像采集装置,采集粉尘颗粒图像并获取采集图像时的粉尘质量浓度。编写粉尘样本图像处理算法,提取图像的灰度特征、纹理特征、几何特征相关参数。对提取的图像特征与实测粉尘质量浓度进行相关性分析,选取相关性较大的图像特征作为参数建立回归数学模型。提取粉尘颗粒对象像素点个数,结合转换系数,基于几何当量等效面积径计算粉尘粒径大小及分布范围。实验结果表明:实测粉尘质量浓度与建立的图像特征多元非线性回归模型数学模型计算值间的平均相对误差为12.37%,标准实测粒径与几何当量等效面积径得到的粒径分布间的最大相对误差为8.63%,平均相对误差为6.37%,验证了基于图像特征的粉尘质量浓度回归数学模型和基于几何当量等效面积径分布数学模型的准确性。

改进7N喷头阻隔CO扩散有效性的模拟研究

为弥补常规组合式喷头存在的挡烟空隙不足,在普通7N喷头的基础上改进,设计出一种侧喷式7N喷头,并开展了数值模拟研究。通过对比下游截面处CO总质量通量、流场分布以及温度的变化情况,验证了改进喷头挡烟的有效性。在此基础上,分析了改进喷头在不同火源功率、流量、粒径下的作用效果。结果表明,普通喷头形成的雾幕能够有效降低通道温度,但并不能阻隔CO的扩散。在同样条件下,改进后的雾幕能够有效抑制CO蔓延,降温能力也有所提高,且其作用效果随喷头流量的增大更加显著。在流量为11.42 L/min时,下游CO质量通量及最高温度较改进前分别降低了71.64%、30.05%;即使火源功率增大至5 MW,改进后的雾幕仍能有效限制CO扩散;总体来看,粒径对CO的阻挡影响并不明显,对2 MW火灾的降温效果也在粒径200 m时达到最佳。

弧叶搅拌器不同桨叶直径下混合性能受转速和高度的影响程度分析

为了探究转速和安装高度对不同搅拌桨直径混合性能的影响程度,以弧叶搅拌器为研究对象,采用Realizablek-ε湍流模型和欧拉多相流模型进行数值计算,对比分析了不同搅拌桨直径在不同安装高度和转速下的混合时间、单位体积混合能、功率、固相颗粒分布、湍动能以及速度流场分布情况。结果表明:当搅拌桨直径增加时,转速对混合时间和固相颗粒运动的影响程度先减小后增加,对功率、湍动能以及介质流速的影响程度增加,对单位体积混合能无明显影响;当搅拌桨直径增加时,安装高度对混合时间和固相颗粒运动的影响程度先减小后增加再减小,搅拌桨直径为400mm时影响程度最大,对功率、湍动能以及介质流速无明显影响;当安装高度低于H/3时,随着搅拌桨直径的增加,高度对单位体积混合能的影响程度先增加后减小,反之,高度对单位体积混合能的影响程度增加。该研究可以在一定程度上说明搅拌桨直径在设计参数发生变化时对流场的影响程度,能够为机械搅拌提供理论指导,具有一定的工程应用意义。

塿土胶体对氮磷钾吸附性能的尺寸效应

为明确尺寸效应对塿土胶体吸附氮、磷、钾行为的影响过程及机理,采用高速离心法提取直径<2000、<1000、<500、<200 nm和<100 nm的塿土胶体组分,测定其粒径分布、元素含量和zeta电位,进而通过批量吸附试验研究其对铵根离子(NH_(4)^(+))、磷酸根离子(PO_(4)^(3-))和钾离子(K^(+))的吸附行为。结果表明:直径<2000 nm和<1000 nm的塿土粗胶体颗粒呈双峰分布模式,直径<500、<200 nm和<100 nm的细胶体组分呈单峰分布。随着平均直径减小,塿土胶体的全碳和有机碳含量增加。不同直径塿土胶体在高pH下的zeta电位绝对值增大,电荷密度和电荷可变性也随颗粒直径增大而增加。各直径塿土胶体对NH_(4)^(+)、PO_(4)^(3-)、K^(+)的吸附过程符合准一级动力学和Freundlich模型,吸附过程以物理扩散为主,且表现为多分子层吸附特征。不同直径塿土胶体对NH_(4)^(+)、PO_(4)^(3-)、K^(+)的的吸附性能受胶体直径大小的影响,塿土粗胶粒(<2000 nm)吸附能力最大,表明塿土胶体对养分元素的吸附差异主要受电荷密度调控。

一种改良微网式雾化器的设计与应用

该研究设计了一种改良微网式雾化器。该雾化器整机尺寸小、易携带,兼具超声雾化器的低噪声运行与空气压缩式雾化器的雾化颗粒直径小的特点。该雾化器在设计阶段充分考虑使用中可能出现的问题,通过斜角杯底雾化杯设计、清洁模式设置、微网式喷头采用振动筛网雾化网片等方法,克服了目前市面上微网式雾化器的残留药液量较大、雾化网片易堵塞、产热效应较高、雾化颗粒直径过小的缺点。经用户体验反馈,证明该改良微网式雾化器使用方便,功能完善。

某催化裂化装置催化剂破碎跑损诊断分析

某1.0 Mt/a催化裂化装置正常运行中突然出现催化剂跑损(跑剂)故障,且无减小趋势,过程中工艺操作参数无异常,外排烟气颗粒物浓度和油浆固含量超标。通过分析系统内催化剂的粒度分布、APS(平均粒径)、形貌等变化,发现催化剂发生了严重的破碎,产生了大量细粉。核算发现,该装置主风分布器喷嘴和进料喷嘴气速均未发生变化,汽提蒸汽管的压力降发生了较大的变化,蒸汽喷出线速度远超设计值,达到75 m/s以上,故推测催化剂跑损原因为汽提蒸汽管断裂导致的催化剂冲击破碎和热崩破碎。采取降低装置加工负荷、减少两器通入蒸汽量、加大平衡剂置换量等措施,在满足装置不停工的前提下有效地降低了催化剂跑损量。

稻蟹共作对土壤理化性质及土壤酶活性的影响

为探究稻蟹共作对土壤理化性质及土壤酶活性的影响,采用水泥池模拟稻田环境的方法,对比研究了稻蟹共作与水稻单作模式7个土壤理化指标和4个土壤酶活性的差异。结果表明:与稻田单作相比,稻蟹共作对土壤容重、土壤含水率和土壤还原性物质总量均有显著影响(P<0.05);稻蟹组的总有机碳略高于稻田组,但总氮略低于稻田组;稻蟹组与稻田组的Eh存在极显著差异,两组之间差异达20.95%;稻蟹组和稻田组土壤粒径机械组成均为粉粒>粘粒>粗细砂粒,粉粒占比均超过80%,且两组之间存在显著差异(P<0.05);随着土壤深度的增加,稻田组的四种酶活性均呈显著下降趋势;稻蟹组的脲酶、纤维素酶和蔗糖酶活性变化与稻田组一致,呈显著下降趋势,但其酸性磷酸酶没有变化。可见,稻蟹共作系统由于河蟹的引入,降低了土壤容重,提高了土壤含水率,改良了土壤,其水稻根系分布较多的10~15 cm底层土壤显示了较强的土壤酶活性,促进了水稻对稻蟹共作系统中碳、氮等元素的高效利用。因此,稻蟹共作系统既有利于水稻生长,又有利于河蟹养殖,可以作为一种生态种养模式在江苏地区推广应用。

Particle morphology control for spherical powder fabrication using the ball milling process with DEM simulation

Characteristics of spherical particles on copper powder and changing sizes were studied in a ball mill under various experimental conditions,such as different ball diameters,high rotation speeds,and milling times,using a discrete element method(DEM)simulation.This experiment has investigated the characteristics of spherical particle morphology evolution involved in the mechanical alloying of copper powder.The morphological evolution of the copper particle was analyzed using scanning electron microscopy(SEM).A spherical copper particle was shown with a roundness value using imageJ software.The DEM was used to simulate the ball motion in a planetary ball mill,and the impact energy and shear energy generated during the collision were analyzed to estimate the contact number between the ball and the ball wall.Therefore,as the size of the ball decreased,the number of ball-to-ball and ball-to-wall contacts increased accordingly,and the spherical shape of the copper powder changed.

Incense smoke(IS)inhalation exposure system:Physicochemical characterization,IS particle deposition and clearance in human airway using MPPD model

Incense smoke(IS)is source of indoor air pollution and key risk for diverse human diseases.Less in-formation is available regarding controlled IS rodent inhalation exposure system and IS particulate matter(PM)deposition in human airways.Study aimed to demonstrate stable ISPM physicochemical parameters of 10 incense products inside the customized whole body inhalation exposure chamber(without animal)connected to smoke generation unit via aerosol mixing device.IS analyzed for size segregated PM emission,ISPM in vitro aerodynamics(MMAD and GSD determination),fine and ultrafine particle's SEM,SEM-EDX and PAH analysis.Using real life exposure scenario by utilizing MMAD,GSD and PM concentration after Tier 1 exposure assessment as key input parameters,ISPM dosimetry in infant(3 months)and adult(21 years male and female)human airways was calculated using multiple-path particle dosimetry(MPPD 3.04)modeling.Mass median aerodynamic diameter(MMAD)and geo-metric standard deviation(GSD)ranged between 0.55 and 2.10μm and 1.22 to 1.77(polydisperse)respectively.PM1.0 and PM0.1 showed multiple morphology and presence of heavy and trace elements.PAH like acenaphthylene,anthracene,fluorene,naphthalene and phenanthrene were detected(0.84-143.17μg/g).MPPD results showed higher ISPM deposition in pulmonary region and lowest in trachea bronchial region.ISPM deposition in tissue was higher in lower,peripheral lung as compared to upper and central lung tissue.Whole body inhalation exposure system showed stable IS atmosphere(physi-cochemical parameters)indicating the device suitability in future inhalation studies.MPPD ISPM deposition fraction and clearance data showed deep lung penetrating and retention behavior with higher risk in infant followed by female and then male.These modeled particle deposition and clearance data may be useful in risk assessment analysis of IS.

Analysis of Snow Distribution and Displacement in the Bogie Region of a High-Speed Train

Snow interacting with a high-speed train can cause the formation of ice in the train bogie region and affect its safety.In this study,a wind-snow multiphase numerical approach is introduced for high-speed train bogies on the basis of the Euler-Lagrange discrete phase model.A particle-wall impact criterion is implemented to account for the presence of snow particles on the surface.Subsequently,numerical simulations are conducted,considering various snow particle diameter distributions and densities.The research results indicate that when the particle diameter is relatively small,the distribution of snow particles in the bogie cavity is relatively uniform.However,as the particle diameter increases,the snow particles in the bogie cavity are mainly located in the rear wheel pairs of the bogie.When the more realistic Rosin-Rammler diameter distribution is applied to snow particles,the positions of snow particles with different diameters vary in the bogie cavity.More precisely,smaller diameter particles are primarily located in the front and upper parts of the bogie cavity,while larger diameter snow particles accumulate at the rear and in the lower parts of the bogie cavity.