scholarly journals Attainable Region Approach in Analyzing the Breakage Behavior of a Bed of Olivine Sand Particles: Optimizing Impact Energy and Particle Size

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1096
Author(s):  
Endene Emmanuel ◽  
Vivi Anggraini ◽  
Agusril Syamsir ◽  
Suvash Chandra Paul ◽  
Afshin Asadi
Keyword(s):  
Particle Size ◽  
Impact Energy ◽  
Size Classes ◽  
Drop Weight ◽  
Attainable Region ◽  
Sand Particles ◽  
Particle Size Classes ◽  
Olivine Sand ◽  
The Impact ◽  
Breakage Behavior

In this study, we investigated the breakage behavior of a bed of olivine sand particles using a drop-weight impact test, with drop weights of various shapes (oval, cube, and sphere). An Attainable Region (AR) technique, which is a model-free and equipment-independent technique, was then applied to optimize the impact energy during the breakage process and also to get particles in defined particle size classes. The findings revealed that the different drop weights produce products within the three different particle size classes (feed, intermediate, and fine). A higher mass fraction of materials in the fine-sized class (−75 μm) was obtained when the spherical drop weight was used relative to the cubic and oval drop weights. The drop height was found to have a significant influence on the breakage process. The AR technique proved to be a practical approach for optimizing impact energy and particle size during the breakage of a bed of olivine particles, with potential application in sustainable soil stabilization projects.

Ground Rubber Tire / Thermoplastic Composites: Effect of Different Ground Rubber Tires

1993 ◽  
Vol 66 (4) ◽  
pp. 664-677 ◽  
Author(s):  
P. Rajalingam ◽  
J. Sharpe ◽  
W. E. Baker
Keyword(s):  
Particle Size ◽  
Impact Energy ◽  
Surface Oxidation ◽  
Surface Concentration ◽  
Thermoplastic Composites ◽  
Beam Radiation ◽  
Rubber Tire ◽  
Ground Rubber ◽  
Surface Modification Techniques ◽  
The Impact

Abstract Thermoplastic composites containing different Ground Rubber Tire (GRT) materials, Linear Low Density Polyethylene (LLDPE) and, in some case, a coupling agent (IB‘E’, an ethylene glycidyl methacrylate copolymer) were prepared by melt blending. The impact energies of all the thermoplastic composites (normally containing 40 wt % GRT) were evaluated using an instrumented impact tester. The effects of the GRT particle-size, particle size distribution and shape, the mode of grinding, and the oxygen surface concentration were analyzed. The wet-ambient-ground GRT based composites show higher surface oxidation and give better impact energy than cryo-ground and normal air-ground GRT based composites. Smaller GRT particle size results in a small increase in the impact property of the composite and a greater influence on the melt processability of the composites. Of the different GRT surface modification techniques studied for improved composite interfacial adhesion and impact properties the composites from electron beam radiation treated GRT yield higher increases in impact energy in comparison to corona and plasma treated GRT based composites.

Modelling the influence of total suspended solids on E. coli removal in river water

2015 ◽  
Vol 73 (6) ◽  
pp. 1320-1332 ◽  
Author(s):  
Jueying Qian ◽  
Evelyn Walters ◽  
Peter Rutschmann ◽  
Michael Wagner ◽  
Harald Horn
Keyword(s):  
Particle Size ◽  
Large Scale ◽  
Suspended Solids ◽  
Total Suspended Solids ◽  
Sensitivity Coefficient ◽  
Fecal Indicator ◽  
E Coli ◽  
Size Classes ◽  
Sedimentation Process ◽  
Particle Size Classes

Following sewer overflows, fecal indicator bacteria enter surface waters and may experience different lysis or growth processes. A 1D mathematical model was developed to predict total suspended solids (TSS) and Escherichia coli concentrations based on field measurements in a large-scale flume system simulating a combined sewer overflow. The removal mechanisms of natural inactivation, UV inactivation, and sedimentation were modelled. For the sedimentation process, one, two or three particle size classes were incorporated separately into the model. Moreover, the UV sensitivity coefficient α and natural inactivation coefficient kd were both formulated as functions of TSS concentration. It was observed that the E. coli removal was predicted more accurately by incorporating two particle size classes. However, addition of a third particle size class only improved the model slightly. When α and kd were allowed to vary with the TSS concentration, the model was able to predict E. coli fate and transport at different TSS concentrations accurately and flexibly. A sensitivity analysis revealed that the mechanisms of UV and natural inactivation were more influential at low TSS concentrations, whereas the sedimentation process became more important at elevated TSS concentrations.

Effect of specimen size and ball size on breakage throughput in the drop-weight test

2018 ◽  
Vol 233 (2) ◽  
pp. 202-210 ◽  
Author(s):  
Mehdi Akhondizadeh ◽  
Masoud Rezaeizadeh
Keyword(s):  
Impact Energy ◽  
Specimen Size ◽  
Test Machine ◽  
Ball Size ◽  
Drop Weight ◽  
Weight Test ◽  
Drop Weight Test ◽  
Steel Balls ◽  
The Impact ◽  
Specific Impact

Effects of specimen size and ball size on the breakage throughput under the impact loading are investigated using a drop-weight test machine. Samples are square-shaped building stones ranging 20–60 mm in width and 22–256 g in mass. They include granite, marble, and two types of travertine with the thickness of 15 mm. The impact energies, up to 160 J, are achieved by falling balls in a drop-weight test machine. Several steel balls with the diameter of 60, 84, 96, and 120 mm have been used as an impactor. The ball size is a parameter whose effect on the breakage throughput is investigated here. Results show that the larger specimens have better breakage than the smaller ones at the same specific impact energy. It is also indicated that, at constant specific impact energy, the smaller balls behave more efficiently than the larger balls.

Impact resistance of Nomex honeycomb sandwich structures with thin fibre reinforced polymer facesheets

2016 ◽  
Vol 20 (5) ◽  
pp. 531-552 ◽  
Author(s):  
Longquan Liu ◽  
Han Feng ◽  
Huaqing Tang ◽  
Zhongwei Guan
Keyword(s):  
Finite Element ◽  
Impact Energy ◽  
Sandwich Structures ◽  
Impact Resistance ◽  
Impact Response ◽  
Woven Fabric ◽  
Drop Weight ◽  
Honeycomb Sandwich ◽  
Nomex Honeycomb ◽  
The Impact

In order to investigate the impact resistance of the Nomex honeycomb sandwich structures skinned with thin fibre reinforced woven fabric composites, both drop-weight experimental work and meso-mechanical finite element modelling were conducted and the corresponding output was compared. Drop-weight impact tests with different impact parameters, including impact energy, impactor mass and facesheets, were carried out on Nomex honeycomb-cored sandwich structures. It was found that the impact resistance and the penetration depth of the Nomex honeycomb sandwich structures were significantly influenced by the impact energy. However, for impact energies that cause full perforation, the impact resistance is characterized with almost the same initial stiffness and peak force. The impactor mass has little influence on the impact response and the perforation force is primarily dependent on the thickness of the facesheet, which generally varies linearly with it. In the numerical simulation, a comprehensive finite element model was developed which considers all the constituent materials of the Nomex honeycomb, i.e. aramid paper, phenolic resin, and the micro-structure of the honeycomb wall. The model was validated against the corresponding experimental results and then further applied to study the effects of various impact angles on the response of the honeycomb. It was found that both the impact resistance and the perforation depth are significantly influenced by the impact angle. The former increases with the obliquity, while the latter decreases with it. The orientation of the Nomex core has little effect on the impact response, while the angle between the impact direction and the fibre direction of the facesheets has a great influence on the impact response.

scholarly journals The effects of gravel cushion particle size and thickness on the coefficient of restitution in rockfall impacts

2018 ◽  
Vol 18 (6) ◽  
pp. 1811-1823 ◽  
Author(s):  
Chun Zhu ◽  
Dongsheng Wang ◽  
Xing Xia ◽  
Zhigang Tao ◽  
Manchao He ◽  
...  
Keyword(s):  
Particle Size ◽  
Impact Energy ◽  
Coefficient Of Restitution ◽  
Open Pit ◽  
Test Results ◽  
Drop Tests ◽  
Damage Depth ◽  
The Stability ◽  
Energy Absorbing ◽  
The Impact

Abstract. Gravel cushions are widely used to absorb the impact energy of falling rocks in open-pit mines. A particularly important application is to enhance the energy-absorbing capacity of rockfall sheds. In this paper, we study how varying the thickness and particle size of a gravel cushion influences its energy-consumption and buffering effects. We performed a series of laboratory drop tests by dropping blocks from a fixed height onto cushions of different thicknesses and particle sizes. The results indicate that, for a given impact energy, the cushion thickness has a strong influence on the measured coefficient of restitution (COR) and therefore impact pressure. Additional tests were performed to study how the radius of the block and the height it is dropped from affect the measured COR. This showed that as the movement height of the block is increased the COR also increases, and blocks with larger radii exhibit a larger variability in measured COR. Finally, we investigated the influence of rockfall block radius, r, movement height, H, cushion thickness, h, and particle size, d, on the COR and the damage depth, L, of the cushion. The test results reveal that the cushion thickness is the primary design parameter, controlling not only COR, but also the stability of the cushion material. The results provide a theoretical and practical basis for the design of gravel cushions for rockfall protection.

Relationship between Impact Energy and Flexural Toughness Energy of Steel Fiber Reinforced Lightweight Aggregate Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 385-388
Author(s):  
Hai Tao Wang ◽  
Jin Qing Jia
Keyword(s):  
Impact Energy ◽  
Impact Resistance ◽  
Lightweight Aggregate ◽  
Steel Fibers ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Flexural Toughness ◽  
Drop Weight ◽  
Flexural Tests ◽  
The Impact

In order to determine the impact resistance of lightweight aggregate concrete (LWC), especially the effect of steel fibers on impact resistance of LWC, a series of drop-weight tests, recommended by the ACI committee 544, have been carried out in the present study. Impact and flexural tests were carried out on lightweight aggregate concrete reinforced with five different percentages of steel fibers 0.0%, 0.5%, 1.0%, 1.5% and 2.0% by volume of concrete. For each volume of fibers, complete load–deflection curves of SFLWC were generated in order to determine the total energy absorbed for each specimen. The addition of steel fibers to concrete has improved impact resistance and also the flexural toughness. The test results showed that a logarithmic relation exists between flexural toughness energy by means of the generated load–deflection curves from the flexural tests and the impact energy by means of drop-weight tests.

scholarly journals Comparative selective retention of particle size classes in the gastrointestinal tract of ponies and goats

2017 ◽  
Vol 102 (2) ◽  
pp. 429-439 ◽  
Author(s):  
J. Hummel ◽  
F. Scheurich ◽  
S. Ortmann ◽  
L. A. Crompton ◽  
M. Gerken ◽  
...  
Keyword(s):  
Particle Size ◽  
Gastrointestinal Tract ◽  
Size Classes ◽  
Selective Retention ◽  
Particle Size Classes
Sign in / Sign up

Export Citation Format

Share Document