检索结果-南通市图书馆

In-situ investigation on real-time suspended sediment measurement techniques:Turbidimetry, acoustic attenuation,laser diffraction (LISST) and vibrating tube densimetry

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2018年第1期33卷 3-17页

作者： David Felix Ismail Albayrak Robert Michael Boes Laboratory of Hydraulics Hydrology and Glaciology(VAW)ETH Zürich

Real-time measurements of Suspended Sediment mass Concentration（SSC） and Particle Size Distribution（PSD） are of prime importance for the investigation and management of fine-sediment related processes in surface water systems and hydraulic schemes. In a field study at the waterway of the hydropower plant（HPP） Fieschertal in the Swiss Alps, the real-time measurement performance of the following techniques and instruments were assessed based on measurements in the sediment seasons of the years 2013 and 2014:（1） turbidimetry,（2） single-frequency acoustic attenuation using a standard acoustic discharge measurement（ADM） installation,（3） laser diffraction（laser In-Situ Scattering and Transmissometry, LISST）, and（4） vibrating tube densimetry using a Coriolis Flow and Density Meter（CFDM）.Reference SSCs were obtained from gravimetric analysis of 219 automatically pumped water *** additionally supplied PSD every minute. The median particle diameter, d50, was usually 15μm and increased occasionally to 100μm. The turbidimeter and the ADM underestimated the SSC when the transported particles were coarser than usual. Such temporary biases resulted from the poor correlation between d50and SSC at this study site. The SSCs from CFDM and LISST were not or less biased by PSD variations. Mainly due to angular and flaky particle shapes, SSC from LISST needed a correction by 79% on average. With the usually prevailing silt particles, an optical path length of 5 mm and no dilution, the SSC measurement range of LISST was limited to about 1.5 g/l. The CFDM allowed measuring higher SSC than the other investigated instruments（e.g. up to 13.5 g/l）. With a periodic offset correction, its relative SSC measurement uncertainty was < 20% for SSC≥ 1.5 g/I. To reliably measure a wide range of SSC with temporarily variable PSD, a combination of instruments is recommended: e.g. a standard LISST, a CFDM,and an automatic water sampler for gravimetric reference measurements.

关键词： Suspended sediment concentration Turbidity Acoustic attenuation laser diffraction Coriolis flow and density meter Gravimetric analysis

Soil particle size range correction for improved calibration relationship between the laser-diffraction method and sieve-pipette method

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Pedosphere 2021年第1期31卷 134-144页

作者： Weiwen QIU Wei HU Denis CURTIN Lidia MOTOI New Zealand Institute for Plant&Food Research Limited Private Bag 4704Christchurch 8140New Zealand

Particle size fraction(clay, silt, and sand) is an important characteristic that influences several soil functions. The laser-diffraction method(LDM) provides a fast and cost-effective measurement of particle size distribution, but the results usually differ from those obtained by the traditional sieve-pipette method(SPM). This difference can persist even when calibration is applied between the two methods. This partly relates to the different size ranges of particles measured by the two methods as a result of different operational principles, i.e., particle sedimentation according to Stokes’ Law vs. Mie theory for laser beam scattering. The objective of this study was to identify particle size ranges of LDM equivalent to those measured by SPM and evaluate whether new calibration models based on size range correction can be used to improve LDM-estimated particle size fractions, using 51 soil samples with various texture collected from five soil orders in New Zealand. Particle size distribution was determined using both LDM and SPM. Compared with SPM, original data from LDM underestimated the clay fraction(< 2 μm), overestimated the silt fraction(2–53 μm), but provided a good estimation of the sand fraction(53–2 000 μm).Results from three statistical indices, including Pearson’s correlation coefficient, slope, and Lin’s concordance correlation coefficient, showed that the size ranges of < 2 and 2–53 μm defined by SPM corresponded with the < 5 and 5–53 μm size ranges by LDM, respectively. Compared with the traditional calibration(based on the same particle size ranges), new calibration models(based on the corrected size ranges of these two methods) improved the estimation of clay and silt contents by LDM. Compared with soil-specific models(i.e., different models were developed for different soils), a universal model may be more parsimonious for estimating particle size fractions if the samples to be assessed represent multiple soil orders.

关键词： laser diffraction Lin’s concordance correlation coefficient particle size distribution Pearson’s correlation coefficient sedimentation method soil separate soil texture

Determination of deferasirox particle size distribution via laser diffraction and its application in establishing a correlation between particle size and drug dissolution in vitro

在线全文

学校读者我要写书评

暂无评论

Journal of Chinese Pharmaceutical Sciences 2021年第11期30卷 912-923页

作者： Yuyuan Chen Song Wu Liqing Chen Yuanyuan Zhang Zhonggao Gao Tianlei Li Wei Huang Qingyun Yang State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of MateriaMedicaChinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100050China

Deferasirox is the first-line drug for iron overload due to thalassemia in adults and pediatric patients. It is classified as a type II compound in the Biopharmaceutics Classification System, and thus the particle size of its active pharmaceutical ingredient(API) should be strictly controlled during the manufacturing process. In the present study, laser diffraction was adopted to measure the particle size distribution of deferasirox API. We also developed and validated an accurate and convenient method by investigating important optical parameters and sample dispersing conditions. The relative standard deviation values, namely, d(0.1), d(0.5), d(0.9), and d(4,3), measured via methodology validation and actual sample measurement were < 3%. The dissolution curves of several batches of dispersible tablets prepared using deferasirox with different particle sizes were compared in the four dissolved media to investigate the influence of particle size on drug dissolution in vitro. Results indicated that the particle size distribution of deferasirox API significantly affected the release of its dispersible tablet.

关键词： Deferasirox Particle size distribution laser diffraction Dissolution curve

Dynamic evolution of low-viscosity fuel particle distribution driven by constant flow

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2023年第7期32卷 416-427页

作者：杨仲坤安高军徐曦萌郑哲王永旭解立峰张丹李斌 School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210000China Institute of Systems Engineering AMSPLABeijing 100000China

The effects of mass concentration and injection pressure on the atomization characteristics of low-viscosity fuel spray are studied in a constant-volume *** spray parameters are measured by laser diffraction at different axial and radial positions downstream of the *** results show that the atomization effect is inhibited linearly with the increase of mass *** increase of injection pressure promotes the droplet ***,the trend gradually weakens and becomes more noticeable at high *** with the concentration,the influence of the injection pressure on the atomization characteristics is *** low concentration and high injection pressure can promote the droplet breakup,they also increase the probability of droplet collision,resulting in droplet *** is more evident in low-viscosity *** droplet size increases in the axial direction owing to the ***,the diameter decreases in the radial direction owing to the outward deflection of small droplets caused by air turbulence and *** addition,the high-velocity airflow significantly promotes the droplet breakup near the nozzle and spray axis regions and inhibits the aggregation ***,the lower-viscosity fuels keep smaller droplet sizes and better atomization in the whole spraying process,which is easier to realize than the higher-viscosity ***,low concentration,high injection pressure,and low viscosity of fuel have beneficial effects on the droplet *** is very important for improving the atomization effect of fuel.

关键词： low-viscosity fuel spray and atomization particle distribution laser diffraction

Light scattering:A review of particle characterization applications

在线全文

学校读者我要写书评

暂无评论

Particuology 2015年第1期13卷 11-21页

作者： Renliang Xu Micromeritics Instrument Corporation

This review covers the progress of light scattering applications in the field of particle characterization in the past decade. The review addresses static light scattering （the measurement of scattering intensities due to light-particle interaction at various spatial locations）, dynamic light scattering （the measurement of scattering due to light-particle interaction as a function of time）, and scattering tracking analysis （the tracking of particle movement through scattering measurement）.

关键词： Dynamic light scattering Particle tracking analysis Electrophoretic light scattering laser diffraction Particle counter Self-mixing laser spectroscopy

Development of droplet characteristics prediction models for air induction nozzles based on wind tunnel tests

在线全文

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2019年第6期12卷 1-6页

作者： Juan Liao Andrew John Hewitt Pei Wang Xiwen Luo Ying Zang Zhiyan Zhou Yubin Lan Chris O’Donnell College of Engineering South China Agricultural University/Engineering Research Center for Agricultural Aviation Application(ERCAAA)Guangzhou 510642China Key Laboratory of Key Technology on Agricultural Machine and Equipment(South China Agricultural University) Ministry of EducationGuangzhou 510642China National Joint Research Center for Precision Agricultural Aviation Application Technology Guangzhou 510642China The University of Queensland GattonQueensland 4343Australia School of Electrical and Information Engineering Jiangsu UniversityZhenjiang 212013China

Nozzle flowrate and spray pressure are two of the most important factors influencing on droplet *** the aim to develop prediction models for air-induction nozzles(AINs),a series of Billericay Farm Services(BFS)AINs with different orifice diameters in combination with tap water were tested.0.2 MPa,0.3 MPa,0.4 MPa,0.5 MPa,0.6 MPa and 0.7 MPa of spray pressures and 2 m/s,3 m/s,4 m/s and 5 m/s of air speeds were *** on the wind tunnel tests data,prediction models with input variables of nozzle flowrate and spray pressure and output variables of D_(v0.1),D_(v0.5),D_(v0.9),%<150μm(proportion of spray volume contained in droplets with diameter below 150μm),relative span(RS)and coefficient of variation(CV)of D_(v0.5) were *** developed models were validated based on wind tunnel experimental *** showed that:for D_(v0.1),D_(v0.5),D_(v0.9) and%<150μm,R^(2) were equal to 0.768,0.823,0.868 and 0.811,indicating that the predictive ability for these four parameters is *** RS and CV,R^(2) were equal to 0.100 and 0.113,respectively,indicating that the predictive ability for these two parameters is *** models developed in the present study are helpful for facilitating the use of AIN in agricultural spray application.

关键词： prediction model agricultural spray application droplet characteristics AIN laser diffraction

A Constitutive Modeling and Experimental Effect of Shock Wave on the Microstructural Sub-strengthening of Granular Copper

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Metallic Material Research 2021年第1期4卷 19-25页

作者： A.D.Sharma A.K.Sharma N.Thakur Department of Physics Government College ChowariChamba176302India Om Sterling Global University-Hisar Haryana125001India Department of Physics Himachal Pradesh UniversityShimla171005India

Micro-sized copper powder(99.95%;O≤0.3)has been shock-processed with explosives of high detonation velocities of the order of 7.5 km/s to observe the structural and microstructural *** shock-consolidation technique has been used to obtain conglomerates of granular *** technique involves the cylindrical compaction system wherein the explosive-charge is in direct proximity with the powder whereas the other uses indirect shock pressure with die-plunger *** simulations have been performed on with Eulerian code *** simulated results show a good agreement with the experimental observation of detonation parameters like detonation velocity,pressure,particle velocity and shock pressure in the reactive media.A pin contactor method has been utilized to calculate the detonation pressure *** angled x-ray diffraction studies reveal that the crystalline structure(FCC)of the shocked specimen matches with the un-shocked *** emissive scanning electron microscopic examination of the compacted specimens show a good sub-structural strengthening and complement the theoretical *** diffraction based particle size analyzer also points towards the reduced particle size of the shock-processed specimen under high detonation ***-hardness tests conducted under variable loads of 0.1 kg,0.05 kg and 0.025 kg force with diamond indenter optical micrographs indicate a high order of micro-hardness of the order of 159 *** pycnometry used for the density measurement of the compacts shows that a compacted density of the order of 99.3%theoretical mean density has been achieved.

关键词： Shock waves Wide angle x-ray diffraction Microstructure FE-SEM laser diffraction Microhardness