scholarly journals DESIGN, DEVELOPMENT AND VALIDATION OF AN IMPACT WEAR TESTING DEVICE FOR THE MINERALS INDUSTRY

1969 ◽  
Author(s):  
Lokesh K. Thakur ◽  
Peter Radziszewski
Keyword(s):  
Wear Mechanism ◽  
High Energy ◽  
Wear Testing ◽  
Impact Wear ◽  
Design Development ◽  
Charge Motion ◽  
Wear Model ◽  
Motion Simulator ◽  
Wide Range ◽  
The Impact

Total steel media wear in a given mill (ball or SAG) grinding process is a product of three recognized wear mechanisms-impact, abrasion, and corrosion of which the contribution of each wear mechanism to total media wear has not been well established. A total media wear model can be defined on the assumption that the effect of each wear mechanism can be independently determined and this effect can be tied to mill charge motion as determined or estimated using a charge motion simulator, which allows for a total media wear model to be defined as the summation of the wear results of each mechanism. This necessitates the need for developing impact, abrasion and corrosion wear testers that will allow the study of media wear over a wide range of energy levels. Refinement of the impact test will allow studying how impact media wear at high energies behaves as a function of those energies. This work is focused on design and development of a high-energy impact wear tester. A comprehensive illustration on designing the newest version of the impact wear tester is explained in detail in order to exhibit how theoretical, virtual and experimental analyses could be integrated while designing a mechanical system.

scholarly journals Repetitive Impact Wear Behaviors of the Tempered 25Cr3Mo2NiWV Fe-Based Steel

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 107
Author(s):  
Cheng Zhang ◽  
Pu Li ◽  
Hui Dong ◽  
Dongliang Jin ◽  
Jinfeng Huang ◽  
...  
Keyword(s):  
Cross Sections ◽  
Wear Mechanism ◽  
Optical Microscope ◽  
Impact Wear ◽  
Wear Properties ◽  
Micro Cracks ◽  
The Cross ◽  
Repetitive Impact ◽  
Surface Morphologies ◽  
The Impact

This study aimed to reveal the impact wear behaviors of tempered 25Cr3Mo2NiWV steel. The specimens were subject to various heat treatment processes for generating different mechanical and wear properties. The impact wear tests were performed with an MLD-10 dynamic abrasive wear tester. Worn surface morphologies and micro-cracks of the cross-sections were analyzed by optical microscope and scanning electron microscope. The Vickers hardness of the sample and the impact wear mechanism were also analyzed. The steel with the best combination of hardness and toughness had the lowest wear. With the increase of wear time, the dominant wear mechanism varied from slight plastic deformation to micro-cutting and adhesive wear. Finally, micro fatigue peeling occurred. After impact wear, the cracks could initiate from the surface or the sub-surface. Micrographs of the crack in the cross-section demonstrated two different propagation modes of fatigue fractures. The results showed that the strength and toughness of steel affected the crack propagation, surface spalling, and wear failure mechanism during impact wear.

Impact of X-ray induced radiation damage on FD-MAPS of the ARCADIA project

2022 ◽  
Vol 17 (01) ◽  
pp. C01035
Author(s):  
C. Neubüser ◽  
T. Corradino ◽  
S. Mattiazzo ◽  
L. Pancheri
Keyword(s):  
Power Consumption ◽  
Radiation Damage ◽  
High Energy ◽  
Full Potential ◽  
Sensor Design ◽  
Charge Collection Efficiency ◽  
X Ray ◽  
Active Pixel ◽  
Wide Range ◽  
The Impact

Abstract Recent advancements in Monolithic Active Pixel Sensors (MAPS) demonstrated the ability to operate in high radiation environments of up to multiple kGy’s, which increased their appeal as sensors for high-energy physics detectors. The most recent example in such application is the new ALICE inner tracking system, entirely instrumented with CMOS MAPS, that covers an area of about 10 m2. However, the full potential of such devices has not yet been fully exploited, especially in respect of the size of the active area, power consumption, and timing capabilities. The ARCADIA project is developing Fully Depleted (FD) MAPS with an innovative sensor design, that uses a proprietary processing of the backside to improve the charge collection efficiency and timing over a wide range of operational and environmental conditions. The innovative sensor design targets very low power consumption, of the order of 20 mW cm−2 at 100 MHz cm−2 hit flux, to enable air-cooled operations of the sensors. Another key design parameter is the ability to further reduce the power regime of the sensor, down to 5 mW cm−2 or better, for low hit rates like e.g. expected in space experiments. In this contribution, we present a comparison between the detector characteristics predicted with Technology Computer Aided Design (TCAD) simulations and the ones measured experimentally. The comparison focuses on the current-voltage (IV) and capacitance-voltage (CV) characteristics, as well as noise estimated from in-pixel capacitances of passive/active pixel matrices. In view of the targeted applications of this technology, an emphasis is set on the modeling of X-ray induced radiation damage at the Si-SiO2 interface and the impact on the in-pixel sensor capacitance. The so-called new Perugia model has been used in the simulations to predict the sensor performance after total ionizing doses of up to 10 Mrad.

Satellite-derived shorelines reveal fascinating dynamics for the last three decades on Danube Delta coast

2021 ◽  
Author(s):  
Florin Tatui ◽  
Georgiana Anghelin ◽  
Sorin Constantin
Keyword(s):  
Satellite Images ◽  
High Energy ◽  
Data Availability ◽  
Danube Delta ◽  
Dune System ◽  
Temporal Scales ◽  
Wide Range ◽  
The Impact ◽  
Sentinel 2

<p>Shoreline, as the interface between the upper shoreface and the beach-dune system, is sensitive to all changes from both the underwater and sub-aerial parts of the beach at a wide range of temporal scales (seconds to decades), making it a good indicator for coastal health. While more traditional techniques of shoreline monitoring present some shortcomings (low temporal resolution for photointerpretation, reduced spatial extension for video-based techniques, high costs for DGPS in-situ data acquisition), freely available satellite images can provide information for large areas (tens/hundreds of km) at very good temporal scales (days).</p><p>We employed a shoreline detection workflow for the dynamic environment of the Danube Delta coast (Black Sea). We focused on an index-based approach using the Automated Water Extraction Index (AWEI). A fully automated procedure was deployed for data processing and the waterline was estimated at sub-pixel level with an adapted image thresholding technique. For validation purposes, 5 Sentinel-2 and 5 Landsat based results were compared with both in-situ (D)GPS measurements and manually digitized shoreline positions from very high-resolution satellite images (Pleiades – 0.5 m and Spot 7 – 1.5 m). The overall accuracy of the methodology, expressed as mean absolute error, was found to be of approximately 7.5 m for Sentinel-2 and 4.7 m for Landsat data, respectively.</p><p>More than 200 Landsat (5 and 8) and Sentinel-2 images were processed and the corresponding satellite-derived shorelines between 1990 and 2020 were analysed for the whole Romanian Danube Delta coast (130 km). This high number of shorelines allowed us the discrimination of different patterns of coastline dynamic and behaviour which could not have been possible using usual surveying techniques: the extent of accumulation areas induced by the 2005-2006 historical river floods, the impact of different high-energy storms and the subsequent beach recovery after these events, the alongshore movement of erosional processes in accordance with the dominant direction of longshore sediment transport, multi-annual differences in both erosional and accumulation trends. Moreover, a very important result of our analysis is the zonation of Danube Delta coast based on multi-annual trends of shoreline dynamics at finer alongshore spatial resolution than before. This has significant implications for future studies dealing with different scenarios of Danube Delta response to projected sea level rise and increased storminess.</p><p>The presented approach and resulting products offer optimal combination of data availability, accuracy and frequency necessary to meet the monitoring and management needs of the increasing number of stakeholders involved in the coastal zone protection activities.</p>

scholarly journals Prediction of Abrasive and Impact Wear Due to Multi-Shaped Particles in a Centrifugal Pump via CFD-DEM Coupling Method

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2391
Author(s):  
Cheng Tang ◽  
You-Chao Yang ◽  
Peng-Zhan Liu ◽  
Youn-Jea Kim
Keyword(s):  
Wear Rate ◽  
Abrasive Wear ◽  
Centrifugal Pump ◽  
Coupling Method ◽  
Particle Model ◽  
Equivalent Diameter ◽  
Impact Wear ◽  
Centrifugal Pumps ◽  
Wear Model ◽  
The Impact

Since solid particles suspended in the fluid can cause wear in centrifugal pumps, intensive attention has been focused on the numerical prediction for the wear of flow parts in centrifugal pumps. However, most numerical studies have focused on only one wear model and a sphere particle model. The impact of particle shape on the wear of flow parts in centrifugal pumps is under-studied, particularly considering abrasive and impact wear simultaneously. In this work, the Computational Fluid Dynamics (CFD)-Discrete Element Method (DEM) coupling method with an abrasive and impact wear prediction model was adopted to study the wear characteristics of a centrifugal pump. Moreover, four regular polyhedron particles and a sphere particle with the same equivalent diameter but different sphericity were mainly analyzed. The results demonstrate that more particles move closer to the blade pressure side in the impeller passage, and particles tend to cluster in specific areas within the volute as sphericity increases. The volute suffers the principal wear erosion no matter what the shapes of particles and wear model are. Both the impact and abrasive wear within the impeller occur primarily on the blade leading edge. The pump’s overall impact wear rate decreases first and then increases with particle sphericity rising, while the pump’s overall abrasive wear rate grows steadily.

scholarly journals Non-standard neutrino and Z′ interactions at the FASERν and the LHC

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Kingman Cheung ◽  
C. J. Ouseph ◽  
TseChun Wang
Keyword(s):  
Large Hadron Collider ◽  
Neutral Current ◽  
Hadron Collider ◽  
Gauge Coupling ◽  
High Energy ◽  
Forward Search ◽  
Neutrino Interactions ◽  
Wide Range ◽  
Search Experiment ◽  
The Impact

Abstract We study the impact of non-standard neutrino interactions in the context of a new gauge boson Z′ in neutral-current deep-inelastic scattering performed in ForwArd Search ExpeRiment-ν (FASERν) and in monojet production at the Large Hadron Collider (LHC). We simulate the neutral-current deep-inelastic neutrino-nucleon scattering νN → νN at FASERν in the presence of an additional Z′ boson, and estimate the anticipated sensitivities to the gauge coupling in a wide range of Z′ mass. At the LHC, we study the effect of Z′ on monojet production, which can be enhanced in regions with large missing transverse momenta. We then use the recent results from ATLAS with an integrated luminosity of 139 fb−1 to improve the limits on the gauge coupling of Z′. We interpret such limits on Z′ gauge couplings as bounds on effective non-standard neutrino interactions. We show that the FASERν and the LHC results cover the medium and high energy scales, respectively, and complement one another.

scholarly journals Perbandingan Pengetahuan Remaja Tentang Dampak Kehamilan pada Remaja Sebelum dan Sesudah Diberikan Pendidikan Kesehatan Reproduksi Melalui Media Video

2019 ◽  
Vol 5 (1) ◽  
pp. 18-24
Author(s):  
Firda Thursyana ◽  
Puspa Sari ◽  
Merry Wijaya
Keyword(s):  
Health Education ◽  
Teenage Pregnancy ◽  
Univariate Analysis ◽  
Sampling Technique ◽  
Wilcoxon Test ◽  
P Value ◽  
Design Development ◽  
Wide Range ◽  
Before And After ◽  
The Impact

A wide range of sexual and reproductive health problems occur among adolescents. The issue is high on teenage pregnancy on nowadays are teenagers. Based on studies of teenage pregnancies in Sumedang-related parenting parents, the influence of friends and dating, as well as media exposure information. This study aims to compare the knowledge of teenagers before and after the given health education about the impact of pregnancy on teens through the medium of video. The methods used in this research was quasi experimental research method with the concept of one group pre test and post test design. Development by way of doing a one time measurement before and after health education was given. Sampling is done using a stratified random sampling technique. The number of samples that used as many as 52 respondents ages 17-19 years as a schoolgirl SMAN Jatinangor. Instrument research using questionnaires with retrieving the data directly. This research using univariate analysis and bivariat with kolmogorov-smirnov test for normality and Wilcoxon test. Research time on July 28, 2016. The results of this research is that before health education 71.2% of respondents knowledgeable enough and after health education changed to 94.2% respondents have knowledge well. There is a difference of knowledge teenagers before and after health education is provided through video on the impacts of teenage pregnancies with p value 0.000.   Summary of the research is given after the teenager's knowledge of health education through the medium of video is higher than before given health education through the medium of video.

scholarly journals The Impact of Anatomical Characteristics on the Structural Integrity of Wood

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 199 ◽  
Author(s):  
Lukas Emmerich ◽  
Georg Wülfing ◽  
Christian Brischke
Keyword(s):  
Structural Integrity ◽  
Growth Ring ◽  
High Energy ◽  
Anatomical Characteristics ◽  
Hardwood Species ◽  
Wide Range ◽  
Ray Density ◽  
Impact Milling ◽  
Multiple Impact ◽  
The Impact

The structural integrity of wood is closely related to its brittleness and thus to its suitability for numerous applications where dynamic loads, wear and abrasion occur. The structural integrity of wood is only vaguely correlated with its density, but affected by different chemical, physico-structural and anatomical characteristics, which are difficult to encompass as a whole. This study aimed to analyze the results from High-Energy Multiple Impact (HEMI) tests of a wide range of softwood and hardwood species with an average oven-dry wood density in a range between 0.25 and 0.99 g/cm³ and multifaceted anatomical features. Therefore, small clear specimens from a total of 40 different soft- and hardwood species were crushed in a heavy vibratory ball mill. The obtained particles were fractionated and used to calculate the ‘Resistance to Impact Milling (RIM)’ as a measure of the wood structural integrity. The differences in structural integrity and thus in brittleness were predominantly affected by anatomical characteristics. The size, density and distribution of vessels as well as the ray density of wood were found to have a significant impact on the structural integrity of hardwoods. The structural integrity of softwood was rather affected by the number of growth ring borders and the occurrence of resin canals. The density affected the Resistance to Impact Milling (RIM) of neither the softwoods nor the hardwoods.

Vibration-Wear Characteristics of Cutter in High Speed Ball-End Milling Hardened Steel

2012 ◽  
Vol 522 ◽  
pp. 81-86
Author(s):  
Bin Jiang ◽  
Pei Yi Zhao ◽  
Ji Guang Song ◽  
Bo Chen ◽  
Jin Xuan Bai
Keyword(s):  
High Speed ◽  
End Milling ◽  
Interaction Strength ◽  
Hardened Steel ◽  
Impact Wear ◽  
Fatigue Wear ◽  
Wear Model ◽  
Wear Characteristics ◽  
Ball End Milling ◽  
The Impact

For vibration-wear characteristics of cutter in high speed ball-end milling hardened steel, established vibration-wear model of high speed milling cutter according to the principle of friction work, researched the influence of basic frequency and multiplication frequency of cutter vibration on its wear, and analyzed the interaction between cutter vibration and wear. By means of changing cutter extended length, rotation speed and cutting depth, made the change of cutter vibration, analyzed the influence of cutter vibration on its fretting and impact wear, explored the evolution process of composite vibration wear of cutter. Results show that the interaction between fretting fatigue wear and the impact wear make for cutter vibration-wear, lead to the increase of cutting force and vibration amplitude, and further increase the interaction strength of vibration and wear.

scholarly journals Impact Wear of the Protective Cr3C2-Based HVOF-Sprayed Coatings

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2132 ◽  
Author(s):  
Josef Daniel ◽  
Jan Grossman ◽  
Šárka Houdková ◽  
Martin Bystrianský
Keyword(s):  
Impact Loads ◽  
High Velocity Oxygen Fuel ◽  
Impact Wear ◽  
Dynamic Impact ◽  
Wide Range ◽  
Impact Tester ◽  
The Impact ◽  
Oxygen Fuel ◽  
Sprayed Coatings ◽  
Corrosion And Oxidation

High velocity oxygen-fuel (HVOF) prepared CrC-based hardmetal coatings are generally known for their superior wear, corrosion, and oxidation resistance. These properties make this coating attractive for application in industry. However, under some loading conditions and in aggressive environments, the most commonly used NiCr matrix is not sufficient. The study is focused on the evaluation of dynamic impact wear of the HVOF-sprayed Cr3C2-25%NiCr and Cr3C2-50%NiCrMoNb coatings. Both coatings were tested by an impact tester with a wide range of impact loads. The Wohler-like dependence was determined for both coatings’ materials. It was shown that, due to the different microstructure and higher amount of tough matrix, the impact lifetime of the Cr3C2-50%NiCrMoNb coating was higher than the lifetime of the Cr3C2-25%NiCr coating. Differences in the behavior of the coatings were the most pronounced at high impact loads.

Microfabrication research at the National Submicron Facility

1983 ◽  
Vol 41 ◽  
pp. 86-89
Author(s):  
E.D. Wolf
Keyword(s):  
Integrated Circuits ◽  
Particle Physics ◽  
High Speed ◽  
New Technology ◽  
High Energy ◽  
High Energy Particle ◽  
New Science ◽  
Wide Range ◽  
Intermediate Domain ◽  
Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

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