scholarly journals Seepage Characteristics of Slurry with Particle Additives in the High-Permeability Sand Layer

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Yuan Wang ◽  
Zhikui Wang ◽  
Di Feng ◽  
Sijin Liu ◽  
Shujun Xu ◽  
...  
Keyword(s):  
Particle Size ◽  
Filter Cake ◽  
Sand Layer ◽  
High Permeability ◽  
Permeability Characteristics ◽  
Pass Through ◽  
Additive Particle ◽  
The Stability ◽  
Slurry Shield ◽  
Slurry Viscosity

In the process of the slurry shield construction, the formation of the filter cake is the key to maintain the stability of the excavation face. In high-permeability formation, ordinary pure bentonite slurry is easy to pass through the formation void. Therefore, it is necessary to study the slurry permeability characteristics of the high-permeability sand layer. For the purpose of researching the permeability characteristics of slurry in sandy formation, this paper studies the influence of slurry viscosity on the formation of the filter cake in high-permeability formation under different pressure gradients by the slurry permeability test. The effect of additive particle size on the film-forming gain was studied by adding additives with different particle sizes into pure bentonite slurries with different viscosities. This paper presents a method to determine the optimum slurry viscosity and particle size for high-permeability formation so as to guide the slurry shield construction in high-permeability formation.

scholarly journals Characterization of Astaxanthin Nanoemulsions Produced by Intense Fluid Shear through a Self-Throttling Nanometer Range Annular Orifice Valve-Based High-Pressure Homogenizer

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2856
Author(s):  
Gary B. Smejkal ◽  
Edmund Y. Ting ◽  
Karthik Nambi Arul Nambi ◽  
Richard T. Schumacher ◽  
Alexander V. Lazarev
Keyword(s):  
Particle Size ◽  
Size Reduction ◽  
Hydrodynamic Diameter ◽  
Fluid Shear ◽  
Particle Size Reduction ◽  
Annular Gap ◽  
Oil In Water ◽  
High Pressure Homogenizer ◽  
Pass Through

Stable, oil-in-water nanoemulsions containing astaxanthin (AsX) were produced by intense fluid shear forces resulting from pumping a coarse reagent emulsion through a self-throttling annular gap valve at 300 MPa. Compared to crude emulsions prepared by conventional homogenization, a size reduction of over two orders of magnitude was observed for AsX-encapsulated oil droplets following just one pass through the annular valve. In krill oil formulations, the mean hydrodynamic diameter of lipid particles was reduced to 60 nm after only two passes through the valve and reached a minimal size of 24 nm after eight passes. Repeated processing of samples through the valve progressively decreased lipid particle size, with an inflection in the rate of particle size reduction generally observed after 2–4 passes. Krill- and argan oil-based nanoemulsions were produced using an Ultra Shear Technology™ (UST™) approach and characterized in terms of their small particle size, low polydispersity, and stability.

Stability of a Binary Colloidal Suspension and its effect on Colloidal Processing

1989 ◽  
Vol 155 ◽  
Author(s):  
Wan V. Shih ◽  
Wei-Heng Shih ◽  
Jun Liu ◽  
Ilhan A. Aksay
Keyword(s):  
Particle Size ◽  
Hard Sphere ◽  
Colloidal Particles ◽  
Colloidal Suspension ◽  
Fluid Phase ◽  
Ceramic Processing ◽  
Colloidal Processing ◽  
Interparticle Interactions ◽  
The Stability ◽  
Binary Suspension

The stability of a colloidal suspension plays an important role in colloidal processing of materials. The stability of the colloidal fluid phase is especially vital in achieving high green densities. By colloidal fluid phase, we refer to a phase in which colloidal particles are well separated and free to move about by Brownian motion, By controlling parameters such as pH, salt concentration, and surfactants, one can achieve high packing (green) densities in the repulsive regime where the suspension is well dispersed as a colloidal fluid, and low green densities in the attractive regime where the suspensions are flocculated [1,2]. While there is increasing interest in using bimodal suspensions to improve green densities, neither the stability of a binary suspension as a colloidal fluid nor the stability effects on the green densities have been studied in depth as yet. Traditionally, the effect of using bimodal-particle-size distribution has only been considered in terms of geometrical packing developed by Furnas and others [3,4]. This model is a simple packing concept and is used and useful for hard sphere-like repulsive interparticle interactions. With the advances in powder technology, smaller and smaller particles are available for ceramic processing. Thus, the traditional consideration of geometrial packing for the green densities of bimodal suspensions may not be enough. The interaction between particles must be taken into account.

scholarly journals Numerical Analyses on the Stability of a Deep Coalmine Roadway Passing through a Fault Zone: A Case Study of the Gugui Coalfield in China

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2114
Author(s):  
Yongshui Kang ◽  
Congcong Hou ◽  
Jingyi Liu ◽  
Zhi Geng ◽  
Jianben Chen ◽  
...  
Keyword(s):  
Fault Zone ◽  
Distinct Element ◽  
Three Dimensional ◽  
Tectonic Stress ◽  
Three Dimensional Model ◽  
Support Strategy ◽  
Failure Theory ◽  
Calculation Results ◽  
Pass Through ◽  
The Stability

Massive deformation often occurs when deep coalmine roadways pass through a fault zone due to the poor integrity of rock mass and high tectonic stress. To study deformation characteristics of the surrounding rock in the fault zone of a coalmine, a roadway passing through the FD1041 fault zone in China’s Gugui coalfield was investigated in this research. The geo-stress characteristics of this fault zone were analyzed based on the Mohr failure theory. Furthermore, a three-dimensional model for the experimental roadway in the FD1041 fault zone was built and calculated by a numerical program based on the distinct element method. Stability conditions of the roadway, using several types of support methods, were calculated and compared. Calculation results indicated that pre-grouting provides favorable conditions for the stability of a roadway in a fault zone. Finally, an optimized support strategy was proposed and implemented in the experimental roadway. Monitored results demonstrated that the optimized support strategy is appropriate for this fault zone.

A comparison of particle breakdown during chewing by guanacos (Lama guanicoe) and sheep

1998 ◽  
Vol 1998 ◽  
pp. 136-136
Author(s):  
M.D. Fraser ◽  
D.H. Baker
Keyword(s):  
Particle Size ◽  
Retention Time ◽  
Microbial Fermentation ◽  
Digestive Efficiency ◽  
Particle Size Reduction ◽  
Lama Guanicoe ◽  
Factors Influencing ◽  
Stomach Motility ◽  
Pass Through ◽  
Major Factors

To date, attempts to account for reported differences in digestive efficiency of camelids and ruminants have focused on factors such as stomach motility and the retention time of feed particles. The physical breakdown of forage into particles small enough to pass through the reticulo-omasal orifice is one of the major factors influencing the rate of passage of digesta from the reticulo-rumen in ruminants. Two of the main processes involved in particle size reduction are chewing (pre- and post-regurgitation) and microbial fermentation. While the characteristic vertical and horizontal jaw movement which occurs during mastication in the camelid is believed to allow for efficient use of the premolars and molars in cutting and grinding fibrous feeds, there have been no comparative studies to verify this, and to assess the contribution of chewing to differences in digestibility coefficients. The aim of this experiment was to directly compare particle breakdown during chewing by guanacos and sheep.

greater the probability that the particles will miss the high shear zones on a single pass through the device. For this reason the discharge of many rotor/stator devices is re-stricted with a series of holes or bars, or with a grid, which performs two separate tasks. First, a discharge grid absolutely limits the maximum particle size that can exit the mixer. If the holes on the discharge grid are 2 mm, it is virtually impossible for par-ticles larger than that diameter to pass through the machine. Rotor/stator in-line mix-ers are made with restricting grids as small as 0.5 mm, and a wide range of larger sizes up to 50 mm or even unrestricted outlets. A sample of such grids is presented in Fig. 29. But even the smallest usable discharge grid does not necessarily provide abso-lute control of the required size distributions in the range of fine dispersion. This is the second reason for the restriction on the discharge. By putting a more limiting dis-charge on the outlet, the flow rate through the device for a given set of pumping cir-cumstances (viscosity, density, system suction, and discharge head) is reduced and the residence time in the machine for a given particle or droplet is increased. The longer residence time increases the probability that a particle has to travel through the highest shearing zones and, thereby, be reduced to the smallest size that the machine is capable of producing. • • • • " ' ; • " * * «L £ J- •-

1998 ◽  
pp. 358-360
Keyword(s):  
Particle Size ◽  
Residence Time ◽  
Flow Rate ◽  
Shear Zones ◽  
High Shear ◽  
Single Pass ◽  
Fine Dispersion ◽  
Wide Range ◽  
Maximum Particle ◽  
Pass Through

scholarly journals Nanomaterials and nanotechnology for the delivery of agrochemicals: strategies towards sustainable agriculture

2022 ◽  
Vol 20 (1) ◽  
Author(s):  
Changcheng An ◽  
Changjiao Sun ◽  
Ningjun Li ◽  
Bingna Huang ◽  
Jiajun Jiang ◽  
...  
Keyword(s):  
Particle Size ◽  
Food Security ◽  
Chemical Composition ◽  
Labor Cost ◽  
Small Particle Size ◽  
Agricultural Systems ◽  
The Stability ◽  
New Applications ◽  
Chemical Pesticides ◽  
Improve Food Security

AbstractNanomaterials (NMs) have received considerable attention in the field of agrochemicals due to their special properties, such as small particle size, surface structure, solubility and chemical composition. The application of NMs and nanotechnology in agrochemicals dramatically overcomes the defects of conventional agrochemicals, including low bioavailability, easy photolysis, and organic solvent pollution, etc. In this review, we describe advances in the application of NMs in chemical pesticides and fertilizers, which are the two earliest and most researched areas of NMs in agrochemicals. Besides, this article concerns with the new applications of NMs in other agrochemicals, such as bio-pesticides, nucleic acid pesticides, plant growth regulators (PGRs), and pheromone. We also discuss challenges and the industrialization trend of NMs in the field of agrochemicals. Constructing nano-agrochemical delivery system via NMs and nanotechnology facilitates the improvement of the stability and dispersion of active ingredients, promotes the precise delivery of agrochemicals, reduces residual pollution and decreases labor cost in different application scenarios, which is potential to maintain the sustainability of agricultural systems and improve food security by increasing the efficacy of agricultural inputs. Graphical Abstract

scholarly journals Modelling of dynamics of combustion of biomass in fluidized beds

2004 ◽  
Vol 8 (2) ◽  
pp. 107-126 ◽  
Author(s):  
Jaakko Saastamoinen
Keyword(s):  
Particle Size ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Fuel Mixture ◽  
Linear Increase ◽  
Fuel Feed ◽  
New Process ◽  
Fuel Particles ◽  
The Stability ◽  
Fluidized Bed Boilers

New process concepts in energy production and biofuel, which are much more reactive than coal, call for better controllability of the combustion in circulating fluidized bed boilers. Simplified analysis describing the dynamics of combustion in fluidized bed and circulating fluidized bed boilers is presented. Simple formulas for the estimation of the responses of the burning rate and fuel inventory to changes in fuel feeding are presented. Different changes in the fuel feed, such as an impulse, step change, linear increase and cyclic variation are considered. The dynamics of the burning with a change in the feed rate depends on the fuel reactivity and particle size. The response of a fuel mixture with a wide particle size distribution can be found by summing up the effect of different fuel components and size fractions. Methods to extract reaction parameters form dynamic tests in laboratory scale reactors are discussed. The residence time of fuel particles in the bed and the resulting char inventory in the bed decrease with increasing fuel reactivity and differences between coal and biomass is studied. The char inventory affects the stability of combustion. The effect of char inventory and oscillations in the fuel feed on the oscillation of the flue gas oxygen concentration is studied by model calculation. A trend found by earlier measurements is explained by the model.

scholarly journals Studi Pengaruh Sudut Belokan Sungai Terhadap Volume Gerusan

2017 ◽  
Vol 4 (1) ◽  
pp. 60 ◽  
Author(s):  
Hasdaryatmin Djufri
Keyword(s):  
Experimental Model ◽  
Water Flow ◽  
Model Tests ◽  
Sand Layer ◽  
Flow Discharge ◽  
Layer Density ◽  
Artificial Channel ◽  
River Bends ◽  
The Stability ◽  
River Bend

Scouring occurs along the streams and generally increases in their bend areas. This occurence threaten the stability of buildings and facilities built around those areas. This study was conducted by experimental model tests in a laboratory using an artificial channel made of sand with diameter of 0,47 mm and the sand layer density of 1,47 gr/cm3. To assess the effect of river bends on the extent of scours, the water flow was simulated on the artificial channel in 9 times i.e.; 3 variations in the angle of river bends (α) and 3 variations in the flow discharge (Q) for each river bend variation. This study revealed that the volume of scours positively correlated to the angle of river bends. The volume of scours decreased more 20% when the angle of river bends decresed from 60º to 30º. The increase of the flow discharge also enlarged the volume of scours more than 100% at the river bends with small angles

Novel Fluorescent Visualization Method to Characterize Transport Properties in Micro/Nano Heat Pipe Wick Structures

2009 ◽  
Author(s):  
Pramod Chamarthy ◽  
H. Peter J. de Bock ◽  
Boris Russ ◽  
Shakti Chauhan ◽  
Brian Rush ◽  
...  
Keyword(s):  
Heat Pipe ◽  
High Performance ◽  
Gravitational Force ◽  
Driving Forces ◽  
Electronics Cooling ◽  
Heat Pipes ◽  
High Permeability ◽  
Permeability Characteristics ◽  
Wick Structure ◽  
Initial Results

Heat pipes have been gaining a lot of popularity in electronics cooling applications due to their ease of operation, reliability, and high effective thermal conductivity. An important component of a heat pipe is the wick structure, which transports the condensate from condenser to evaporator. The design of wick structures is complicated by competing requirements to create high capillary driving forces and maintain high permeability. While generating large pore sizes will help achieve high permeability, it will significantly reduce the wick’s capillary performance. This study presents a novel experimental method to simultaneously measure capillary and permeability characteristics of the wick structures using fluorescent visualization. This technique will be used to study the effects of pore size and gravitational force on the flow-related properties of the wick structures. Initial results are presented on wick samples visually characterized from zero to nine g acceleration on a centrifuge. These results will provide a tool to understand the physics involved in transport through porous structures and help in the design of high performance heat pipes.

Dispersion of TiO2 Nanoparticles in Aqueous Solution

2018 ◽  
Vol 922 ◽  
pp. 8-13
Author(s):  
Wen Xiu Liu ◽  
Peng Sun ◽  
Jun Zhang ◽  
Wen Bin Cao
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Mass Fraction ◽  
Adsorption Mechanism ◽  
Secondary Particle ◽  
Aqueous Dispersion ◽  
Ftir Analysis ◽  
Carboxylate Groups ◽  
The Stability ◽  
Potential Test

Stable TiO2aqueous dispersion with an averaged secondary particle size of about 10 nm was achieved by using commercially available dispersant Di-7N. The stability of the dispersion was measured by Zeta-potential test. And the results showed that the optimal mass fraction of Di-7N was 12 wt%. The adsorption mechanism examined by FTIR analysis indicates that the carboxylate groups in Di-7N is absorbed on the surface of nano-TiO2particles and the adsorbed structure is proposed to be bidentate chelating.

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