scholarly journals Changes in Particle Size Composition under Seepage Conditions of Reclaimed Soil in Xinjiang, China

Processes ◽  
2018 ◽  
Vol 6 (10) ◽  
pp. 201 ◽  
Author(s):  
Zizhao Zhang ◽  
Wanghua Sui ◽  
Kaikai Wang ◽  
Guobin Tang ◽  
Xiaoping Li
Keyword(s):  
Particle Size ◽  
Fine Particle ◽  
Granulometric Composition ◽  
Fine Particles ◽  
Land Reclamation ◽  
Sharp Decrease ◽  
Size Composition ◽  
Particle Content ◽  
Reclaimed Soil ◽  
Different Depths

The distribution of reclaimed soil particle size under seepage conditions after the management period will directly determine the success or failure of reclamation work. The geotechnical experimental method was used in this paper to study the changes in the granulometric composition of soil. The results show that the granulometric composition of the reclaimed soil varied obviously at different depths. The granulometric composition of the soil at a depth of 10 cm was not much different from undisturbed reclaimed soil (URS). At a depth of 30 cm, as the sharp decrease of the content of fine particles resulted in coarser reclaimed soil, the soil became more uniform, with an increase in porosity and water content. At a depth of 50 cm, the fine particle content was generally slightly lower than that of URS. At a depth of 70 cm, the fine particle content of the soil greatly exceeded that of the URS, with the finest soil particles and lowest porosity. The main reason for the above-mentioned changes of granulometric composition in the reclaimed soil was the seepage in soil caused by irrigation during the management period. The research results can provide a reference for management after land reclamation at non-metallic mines in Xinjiang, China.

scholarly journals Study of pressurised metered dose inhalers for the purpose of standardization of quality attributes characterizing uniformity of dosing

2021 ◽  
pp. 11-23
Author(s):  
Elena Bezuglaya ◽  
Nikolay Lyapunov ◽  
Vladimir Bovtenko ◽  
Igor Zinchenko ◽  
Yurij Stolper
Keyword(s):  
Particle Size ◽  
Fine Particle ◽  
Fine Particles ◽  
Average Dose ◽  
Metered Dose Inhalers ◽  
Fine Particle Dose ◽  
Particle Dose ◽  
Metered Dose ◽  
Delivered Dose

Aim. The purpose was to provide the rationale of test in regard to uniformity of fine particles dose for pressurised metered dose inhalers (pMDIs). Materials and methods. The pMDIs containing suspensions of salbutamol sulfate (SS) or solutions of beclometasone dipropionate (BD) were studied by laser diffraction and high performance liquid chromatography (HPLC). The particle size distribution of SS, the average dose mass and uniformity of dose mass, the average delivered dose and the uniformity of delivered dose, the average fine particles dose and uniformity of fine particles dose were determined. Apparatus A was used for assessment of fine particles dose. Results. The two analytical procedures for the quantitative determination of SS and BD by HPLC were validated in the ranges with low concentrations of these substances. The 5 medicinal products in pMDI dosage form were studied: 3 preparations were with SS and 2 ones contained BD. It was shown that three products with SS were very similar in regard to particle size distribution in containers and the average values of delivered dose were almost the same, but these products were different in the average dose mass and fine particle dose. According to the research results, the expediency of determining the average dose mass and the tests concerning uniformity of dosing of preparations by dose mass and by fine particle dose was substantiated. It was shown that in the case of pMDI the dosing of solutions of BD was more uniform compared to suspensions of SS. The approaches of leading and other pharmacopoeias concerning uniformity of dosing for pMDIs were critically discussed. The expediency of determination of uniformity of fine particle dose at the stage of pharmaceutical development was substantiated, as the therapeutic effect depends on fine particle dose. Issues concerning standardization pMDIs in regard to uniformity of fine particle dose were discussed. Conclusions. The expediency of standardization and quality control of pMDIs in regard to such attributes as the average dose mass, which characterizes the volume of the metering chamber of the valve as well as the uniformity of the dose mass and the uniformity of fine particle dose, which assure the therapeutic effect of each dose of the product was substantiated

Grain size of deposits in different plantation dunes on the eastern shore of Qinghai Lake

2020 ◽  
Author(s):  
Lihui Tian ◽  
Dengshan Zhang ◽  
Yang Yu
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Surface Sediments ◽  
Size Composition ◽  
Qinghai Lake ◽  
Soil Conditions ◽  
Lake Basin ◽  
Eastern Shore ◽  
Vegetation Growth ◽  
Different Depths

<p>Soil particles are related to vegetation growth and source of depositsc in arid and semi-arid desert. It is worth mentioning that plantation is the one the most effective ways improving desert soil conditions. The sandy land on the eastern shore of Qinghai Lake is the biggest area in the desertified land of Qinghai Lake Basin. Some measures have been taken to prevent and control desertification in Kutu district since 2008. We chose the dunes that planted Salix cheilophila、Hippophae rhamnoides、Pinus sylvestris、Populus simonii and Hedysarum scoparium as study sites, then collected deposits from topsoil to the depth of 60 cm to probe into the change of grain size features. The results show that: (1) All study dunes primarily are made up of medium materials for mean particle size (M) is medium sand widely distributed from 0.27mm to 0.31mm which are presented uniform. (2) The sorting coefficient of sediments is concentrated between 0.5 and 0.9 with better performance. The skewness value is between 0 and 1, which shows nearly symmetrical and positive skewness. The kurtosis is between wide and medium. (3) The vertical change of particle size composition at different depths of 60 cm indicates that plantation significantly changed the distribution of the surface sediments in the dunes, whereas particle compositions at different depths did not have obvious rules of different plants. (4) The vegetation recovery time in study area was short, therefore, interactions between wind sorting, terrain fluctuations and vegetation growth might affect the grain size features of surface sediments in study area.</p>

Study on the New Fine Particle Size Measurement Technique With Laser Interference Fringes

2011 ◽  
Author(s):  
Hiroto Sakaki ◽  
Akiko Kaneko ◽  
Yutaka Abe ◽  
Masatoshi Ike
Keyword(s):  
Particle Size ◽  
Measurement Technique ◽  
Fine Particle ◽  
Fine Particles ◽  
Flow Cell ◽  
Size Measurement ◽  
Laser Interference ◽  
Particle Size Measurement ◽  
Interference Fringes ◽  
Fine Particle Size

We propose one fine partice size measurement technique with laser interference fringes which is expected to achieve both non-contact and in-line measurement of the diameter of several hundred nano meter particles. However, the principle of this measurement technique with laser interference fringes is not clear and applicability of fine particle size measurement is unclear. The objective of this study is to examine the principle of this measurement technique with laser interference fringes and evaluate its applicability. We measure the flow structure in a flow cell which is the test section with Particle Image Velocimetry (PIV) to optimize the setting of the flow cell in the measurement system. From the velocity profile along the flow cell, 20 mm downward from the inlet is set as the measurement point. Next, we visualize the laser interference fringes formed with a high-speed video camera to identify the appearance and the behavior of the laser interference fringes through fine particles in the flow cell. Finally, we measure both the time variation of the intensity of the laser interference fringes and the intensity of the scattering light with photodiodes. Passage time of a particle in the laser beam and the voltage intensity have correlation each other. The effect of particle sizes on the laser signal is discussed.

scholarly journals Effect of Overflow Pipe on the Internal Flow Fields and Separation Performance of W-Shaped Hydrocyclones

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 329
Author(s):  
Lanyue Jiang ◽  
Peikun Liu ◽  
Xinghua Yang ◽  
Yuekan Zhang ◽  
Xiaoyu Li ◽  
...  
Keyword(s):  
Axial Velocity ◽  
Fine Particle ◽  
Fine Particles ◽  
Tangential Velocity ◽  
Internal Flow ◽  
Pipe Diameter ◽  
Separation Performance ◽  
Particle Content ◽  
Air Core ◽  
Overflow Pipe

The entrainment of fine particles in underflow of a grinding-classification hydrocyclone can cause ore overgrinding, which will lead to reductions in both metal recovery and ball mill throughput. To address this problem, this paper proposed a W-shaped hydrocyclone that can effectively reduce underflow fine particle entrainment. Experimental tests and numerical simulations were employed to deeply investigate overflow pipe diameter influence on the separation performance and internal flow field of W-shaped hydrocyclones. The effects of overflow pipe diameter on air core shape, velocity field, pressure field, and separation performance were studied. The results revealed that as the diameter of the overflow pipe increased, air core gradually stabilized, and air core diameter gradually increased. The diameter of stabilized air core was approximately 45% to 55% of overflow pipe diameter. As overflow pipe diameter increased, hydrocyclone pressure drop decreased, energy consumption was reduced, the tangential velocity decreased, outer vortex axial velocity did not change significantly, and inner vortex axial velocity gradually increased. At the same time, zero-velocity points gradually moved outward, and the inner vortex region expanded. By the increase of overflow pipe diameter, both the underflow yield and split ratio gradually decreased, the coarse particle content in the overflow product increased, and the fine particle content in the underflow product gradually decreased.

The Influence of Fine Particle Content (Cement Together with Sand Particles up to 0.25 mm) on Rheological Properties of Concrete Mixture

2018 ◽  
Vol 276 ◽  
pp. 97-102 ◽  
Author(s):  
Mindaugas Daukšys ◽  
Albertas Klovas ◽  
Danutė Vaičiukynienė
Keyword(s):  
Rheological Properties ◽  
Fine Particle ◽  
Fine Particles ◽  
Concrete Mixture ◽  
Mixture Composition ◽  
Test Results ◽  
Particle Content ◽  
Conventional Concrete ◽  
Analytical Formulas ◽  
Sand Particles

The influence of the fine particle content on the rheological properties of the fresh concrete mixture was studied. The change of cement together with sand particles up to 0.25 mm in mixture composition was taken into the consideration. The amount of fine particles in mixture composition varied in the range from 402 to 639 kg per one cubic meter of the concrete mixture. Technological properties of the concrete mixture were established according to the standardized requirements, rheological properties: yield stresses and viscosity of conventional concrete mixture were calculated based on analytical formulas. According to obtained test results, the increase of fine particle content from 481 to 520 kg in mixture reduced the yield stresses from about 557 to 132 Pa. Further increase of fine particle content from 600 to 639 kg showed the rise of yield stress by 3.87 times. On the other hand, the viscosity of concrete mixture gradually decreased (ca. 5.6 times). To sum up, the rheological properties of the concrete mixture were significantly influenced by the content, packing density, fineness, surface texture and particle size distribution of fine particles.

Study on Compressive Strength of Recycled Aggregate Brick with Construction Waste

2011 ◽  
Vol 477 ◽  
pp. 301-307
Author(s):  
Li An Zhou ◽  
Jia Long Chen
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Fine Particle ◽  
Curing Temperature ◽  
Recycled Aggregate ◽  
Particle Content ◽  
Construction Waste ◽  
Maximum Particle Size ◽  
Maximum Particle ◽  
The Impact

Recycling and reusing construction waste has become one of the focus issues which should be solved urgently in China with the rapid urbanization, construction of new countryside and large scale urban renewal. There are some researchers take study on the recycling and application of construction waste, but hasn’t systematic study about compressive strength of recycled aggregate brick until now though production and application of recycled aggregate brick is an important approach to reuse construction waste. This test has discussed the impact on the compressive strength of recycled aggregate brick due to recycled aggregate maximum particle size and fine particle content, water-cement ratio, cement-aggregate ratio, forming pressure and curing mode. These results showed that the finer maximum particle size, the higher fine particle content, forming pressure, curing temperature and humidity have notable impact on the compressive strength of recycled aggregate brick.

Effects of Well Cement Additive Particle Size and Density Towards Overall Blend Characterization

2021 ◽  
Author(s):  
Shameed Ashraf ◽  
Rahmad Haidzar Muhamad Husin ◽  
Fakhuma Ubaidillah Mohd Hafiz
Keyword(s):  
Particle Size ◽  
Fine Particle ◽  
Fine Particles ◽  
Glass Beads ◽  
High Density ◽  
Energy Requirements ◽  
Coarse Particles ◽  
Simple Formulation ◽  
Fine Material ◽  
Compaction Ratio

Abstract Well cementing has evolved tremendously since its first application in the early 1900s. In the past, cement was mixed with water at the optimal ratio and combined with silica, bentonite, and additives according to the conditions of use. This simple formulation cannot serve the full breadth of oilfield applications. As a result, cement blend composition has evolved with advanced materials such as lightweight glass beads, cenospheres, polymeric beads, hematite, silica, manganese tetroxide, and many more. The wide variety of material used combined with poor understanding of the modern blend has resulted in operational issues, causing failures in blend delivery and execution. There have been cases of unfavorable blend leading to operation failure after it got stuck within the silo, unable to be pneumatically transferred. Some blend has high segregation potential, causing components to separate out, leading to problems in terms of mixing and having stable density during execution. The focus of this study is to establish a comprehensive understanding of modern cement blend additives for seamless operational execution. Several commonly used materials have been selected to form a case study of powder additive behavior. These materials are grouped into three categories: light, medium, and heavy density, with specific gravity between 0.1 and 1.9, 2.0 and 3.9, and 4.0 and 6.0 g/cm3, respectively. Each group is further divided into subcategories based on the particle sizes of fine, medium, and coarse. These materials are then characterized in terms of flowability factor, aeration energy, and compaction ratio, which consists of the Carr index and Hausner ratio. These are typical physical flow characteristics of the bulk solids. Results show that particle size and density significantly influence the flowability factor, aeration energy, and compaction ratio of a powder blend. In general, materials with fine particle size tend to have higher resistance to flow when evaluated through the flowability factor. Both medium- and coarse-particle additives tend to have higher flowability factor than fine-particle blends, that results in easier blend movement. Aeration energy requirements are much higher for high-density and coarse particles compared to medium and fine particles. The compaction ratio evaluation shows that coarse materials have lower tendency to compact compared to the fine and medium materials. Based on the established understanding of individual components, mixtures are then formed with the intention of improving the overall blend character. The poor characteristics of a high-density fine material are significantly improved by combining the fine material with a lightweight cenosphere. The high aeration energy requirements of heavy coarse particles can be halved by adding lightweight glass beads. For improved behavior, a different particle size of silica materials can be mixed at optimized ratio. Combining materials to obtain optimal particle-size distribution and density is crucial to ensuring an overall blend with favorable characteristics. The behavior of individual components based on particle size and density has paved the way for effective optimization of blends for seamless operational deliverables

scholarly journals High Concentration Fine Particle Separation Performance in Hydrocyclones

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 307
Author(s):  
Yuekan Zhang ◽  
Meng Yang ◽  
Lanyue Jiang ◽  
Hui Wang ◽  
Jinguang Xu ◽  
...  
Keyword(s):  
Particle Size ◽  
Fine Particle ◽  
Fine Particles ◽  
Volume Fraction ◽  
Separation Performance ◽  
Centrifugal Separation ◽  
Discrete Phase Model ◽  
High Concentration ◽  
Ansys Fluent ◽  
Discrete Phase

The vast majority of current research on hydrocyclone field centrifugal separation focuses on low concentration fluids having volume fraction less than 3%. For high-concentration fluids having volume fractions greater than 10%, which are often encountered in engineering, the law governing particle motion and the classification mechanism are still unclear. In order to gain insights into the interaction between fine particles in the high concentration hydrocyclone field and to improve the hydrocyclone separation performance of these particles, a Dense Discrete Phase Model (DDPM) of the Euler-Eulerian method under the Ansys Fluent 14.5 software was employed. Numerical simulations were carried out to study the characteristics of the hydrocyclone field of dense particles and the influence of parameters, such as the diameter of the overflow outlet, diameter of the underflow outlet, and material concentration, on separation performance. The trajectories and separation efficiencies of two kinds of fine particles with different densities and six different particle sizes at high concentration were obtained. The results show that for the hydrocyclone classification of high-concentration fine particles, particles with large density and small particle size are more likely to enter the internal cyclone and discharge from the overflow. Particles with small density and large particle size are more likely to enter the external cyclone and discharge from the underflow. The research results of this topic could provide a feasible reference and theoretical basis for the centrifugal separation of high-concentration fine particle fluid.

scholarly journals The Effect of Inlet Velocity on the Separation Performance of a Two-Stage Hydrocyclone

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 209 ◽  
Author(s):  
Lanyue Jiang ◽  
Peikun Liu ◽  
Yuekan Zhang ◽  
Xinghua Yang ◽  
Hui Wang
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Fine Particle ◽  
Fine Particles ◽  
Coarse Particle ◽  
Separation Performance ◽  
Two Stage ◽  
Inlet Velocity ◽  
Second Stage ◽  
Median Particle

The “entrainment of coarse particles in overflow” and the “entrainment of fine particlesin underflow” are two inevitable phenomena in the hydrocyclone separation process, which canresult in a wide product size distribution that does not meet the requirement of a preciseclassification. Hence, this study proposed a two-stage (TS) hydrocyclone, and the effects of the inletvelocity on the TS hydrocyclone were investigated using computational fluid dynamics (CFD).More specifically, the influences of the first-stage inlet velocity on the second-stage swirling flowfield and the separation performance were studied. In addition, the particle size distribution of theproduct was analyzed. It was found that the first-stage overflow contained few coarse particlesabove 40 μm and that the second-stage underflow contained few fine particles. The second-stageunderflow was free of particles smaller than 10 μm and almost free of particles smaller than 20 μm.The underflow product contained few fine particles. Moreover, the median particle size of thesecond-stage overflow product was similar to that of the feed. Inspired by this observation, wepropose to recycle the second-stage overflow to the feed for re-classification and to use only thefirst-stage overflow and the second-stage underflow as products. In this way, fine particle productsfree of coarse particle entrainment, and coarse particle products free of fine particle entrainmentcan be obtained, achieving the goal of precise classification.

scholarly journals Parameters Influencing the Emission of Ultrafine Particles during 3D Printing

2021 ◽  
Vol 18 (21) ◽  
pp. 11670
Author(s):  
Radomír Chýlek ◽  
Libor Kudela ◽  
Jiří Pospíšil ◽  
Ladislav Šnajdárek
Keyword(s):  
Particle Size ◽  
3D Printing ◽  
Experimental Evaluation ◽  
Fine Particle ◽  
Ultrafine Particles ◽  
Fine Particles ◽  
3D Printer ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Printing Method

This paper presents a complex and extensive experimental evaluation of fine particle emissions released by an FDM 3D printer for four of the most common printing materials (ABS, PLA, PET-G, and TPU). These thermoplastic filaments were examined at three printing temperatures within their recommended range. In addition, these measurements were extended using various types of printing nozzles, which influenced the emissions considerably. This research is based on more than a hundred individual measurements for which a standardized printing method was developed. The study presents information about differences between particular printing conditions in terms of the amount of fine particles emitted as well as the particle size distributions during printing periods. This expands existing knowledge about the emission of ultrafine particles during 3D printing, and it can help reduce the emissions of these devices to achieve cleaner and safer 3D printer operations.

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