Observations of Wear of Abrasive-Waterjet Nozzle Materials

1994 ◽  
Vol 116 (3) ◽  
pp. 439-444 ◽  
Author(s):  
M. Hashish
Keyword(s):  
Aluminum Oxide ◽  
Tungsten Carbide ◽  
Critical Factor ◽  
Abrasive Waterjet ◽  
Machining Parameters ◽  
Abrasive Material ◽  
Wear Performance ◽  
Wide Range ◽  
Jet Nozzle ◽  
Wear Tests

This paper addresses the wear characteristics of the mixing tube of an abrasive-waterjet nozzle. An effective nozzle material should possess high values of both hardness and toughness. The mixing tube, which is where the abrasives are mixed, accelerated, and focused with the high-pressure waterjet, is the component in the abrasive-water jet nozzle that receives the greatest wear. Accelerated wear tests were conducted on relatively soft (steel) mixing tubes using a typical soft abrasive (garnet sand) and on harder (tungsten carbide) tubes using a harder abrasive material (aluminum oxide). A wide range of candidate tool materials, including several carbides and ceramics, was also tested using actual machining parameters. The tungsten carbide grades exhibited greater longevity than the harder ceramics, such as boron carbide, when garnet abrasives were used. The reverse trend was observed with aluminum oxide abrasives. Wear trends suggest that the wear mechanisms along the mixing tube change from erosion by particle impact at the upstream sections to abrasion at the downstream sections. Linear cutting tests were also conducted on several candidate nozzle materials to gain more information related to wear performance. It was found, for example, that the binder in tungsten carbide, which controls these properties, is a critical factor that also controls the lifetime of tungsten carbide mixing tubes.

scholarly journals Experimental Investigation on Wear Behaviour of AA6082 Aluminium Alloy, Tungsten Carbide and Graphite Hybrid Composites

2020 ◽  
pp. 491-494
Author(s):  
Kiran K ◽  
SuriyaPrakash M ◽  
Ravi Kumar K ◽  
Vijay Kumar M
Keyword(s):  
Tungsten Carbide ◽  
Aluminium Alloy ◽  
Hybrid Composites ◽  
Stir Casting ◽  
Wear Behaviour ◽  
Wear Performance ◽  
Casting Technique ◽  
Frictional Behaviour ◽  
Wear Tests ◽  
Scanning Electron

In this experimental study, Aluminium alloy (AA) 6082 was strengthened with Tungsten Carbide and graphite through stir casting technique. Scanning Electron Microscope (SEM) was employed to study the wear performance of the Al/WC/Gr composites. Wear tests were carried out using a pin-ondisc apparatus. The input parameters in this study are the load applied (4, 8, 12, 16, and 20 kg), speed of sliding (1, 1.5, 2, 2.5 and 3 m/s) and distance slides (1000, 1500, 2000 and 2500 m). Response Surface Methodology (RSM) has been carried the use of MINITAB 14 software program to examine the rate of wear and frictional behaviour of the hybrid composites.

Average Worn Profile of Tires in Europe

2014 ◽  
Vol 42 (3) ◽  
pp. 166-184 ◽  
Author(s):  
Frédéric Biesse ◽  
Jérôme Mahé ◽  
Nicolas Lévy
Keyword(s):  
End Of Life ◽  
Development Process ◽  
Measurement Process ◽  
European Countries ◽  
Analysis Method ◽  
Wear Performance ◽  
Usual Behavior ◽  
Wear Tests ◽  
Pattern Width

ABSTRACT Tire tread wear is a key issue in the tire development process and for tire customers. In order to measure the wear performance, tire manufacturers usually proceed to wear tests and calculate the tire life from those tests. An important point in this tire life computation is the criteria chosen for defining the tire's end of life. In Europe, there is a legal minimum tread depth set to 1.6 mm applicable to 75% of the tread pattern width. However, outside those 75% (i.e., on the shoulder part), no clear and shared limit is defined. Also, the usual behavior of customers to decide when their tires should be changed is not well known. The goal of this 2012 study was to identify an average worn profile of tires in Europe and the behavior of customers for replacing their tires. For that, 3000 tires worn out by customers have been collected in scrapyards and measured in five European countries. In this article, we will present the tire collecting method, the measurement process, the analysis method, and some general results and statistics on this 3000 tire database. Finally, the method to compute the average end of life profile and the resulting profile is given.

scholarly journals Adherence to Ketogenic and Mediterranean Study Diets in a Crossover Trial: The Keto–Med Randomized Trial

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 967
Author(s):  
Matthew J. Landry ◽  
Anthony Crimarco ◽  
Dalia Perelman ◽  
Lindsay R. Durand ◽  
Christina Petlura ◽  
...  
Keyword(s):  
Randomized Trial ◽  
Randomized Clinical Trials ◽  
Secondary Analysis ◽  
Critical Factor ◽  
Detailed Examination ◽  
Diet Patterns ◽  
Time Points ◽  
Study Results ◽  
Wide Range ◽  
Diet Pattern

Adherence is a critical factor to consider when interpreting study results from randomized clinical trials (RCTs) comparing one diet to another, but it is frequently not reported by researchers. The purpose of this secondary analysis of the Keto–Med randomized trial was to provide a detailed examination and comparison of the adherence to the two study diets (Well Formulated Ketogenic Diet (WFKD) and Mediterranean Plus (Med-Plus)) under the two conditions: all food being provided (delivered) and all food being obtained by individual participants (self-provided). Diet was assessed at six time points including baseline (x1), week 4 of each phase when participants were receiving food deliveries (x2), week 12 of each phase when participants were preparing and providing food on their own (x2), and 12 weeks after participants completed both diet phases and were free to choose their own diet pattern (x1). The adherence scores for WFKD and Med-Plus were developed specifically for this study. Average adherence to the two diet patterns was very similar during both on-study time points of the intervention. Throughout the study, a wide range of adherence was observed among participants—for both diet types and during both the delivery phase and self-provided phase. Insight from this assessment of adherence may aid other researchers when answering the important question of how to improve behavioral adherence during dietary trials. This study is registered at clinicaltrials.gov NCT03810378.

scholarly journals MOSAIK and FMI-Based Co-Simulation Applied to Transient Stability Analysis of Grid-Forming Converter Modulated Wind Power Plants

2021 ◽  
Vol 11 (5) ◽  
pp. 2410
Author(s):  
Nakisa Farrokhseresht ◽  
Arjen A. van der Meer ◽  
José Rueda Torres ◽  
Mart A. M. M. van der Meijden
Keyword(s):  
Power System ◽  
Time Domain ◽  
Power Plants ◽  
Transient Stability ◽  
Renewable Energy Sources ◽  
Critical Factor ◽  
Primary Control ◽  
Simulation Approach ◽  
Wide Range ◽  
Grid Side

The grid integration of renewable energy sources interfaced through power electronic converters is undergoing a significant acceleration to meet environmental and political targets. The rapid deployment of converters brings new challenges in ensuring robustness, transient stability, among others. In order to enhance transient stability, transmission system operators established network grid code requirements for converter-based generators to support the primary control task during faults. A critical factor in terms of implementing grid codes is the control strategy of the grid-side converters. Grid-forming converters are a promising solution which could perform properly in a weak-grid condition as well as in an islanded operation. In order to ensure grid code compliance, a wide range of transient stability studies is required. Time-domain simulations are common practice for that purpose. However, performing traditional monolithic time domain simulations (single solver, single domain) on a converter-dominated power system is a very complex and computationally intensive task. In this paper, a co-simulation approach using the mosaik framework is applied on a power system with grid-forming converters. A validation workflow is proposed to verify the co-simulation framework. The results of comprehensive simulation studies show a proof of concept for the applicability of this co-simulation approach to evaluate the transient stability of a dominant grid-forming converter-based power system.

A Mechanistic Approach to the Prediction of Material Removal Rates in Rotary Ultrasonic Machining

1995 ◽  
Vol 117 (2) ◽  
pp. 142-151 ◽  
Author(s):  
Z. J. Pei ◽  
D. Prabhakar ◽  
P. M. Ferreira ◽  
M. Haselkorn
Keyword(s):  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Diamond Particle ◽  
Machining Parameters ◽  
Ultrasonic Machining ◽  
Rotary Ultrasonic Machining ◽  
Stabilized Zirconia ◽  
Mechanistic Approach ◽  
Wide Range

An approach to modeling the material removal rate (MRR) during rotary ultrasonic machining (RUM) of ceramics is proposed and applied to predicting the MRR for the case of magnesia stabilized zirconia. The model, a first attempt at predicting the MRR in RUM, is based on the assumption that brittle fracture is the primary mechanism of material removal. To justify this assumption, a model parameter (which models the ratio of the fractured volume to the indented volume of a single diamond particle) is shown to be invariant for most machining conditions. The model is mechanistic in the sense that this parameter can be observed experimentally from a few experiments for a particular material and then used in prediction of MRR over a wide range of process parameters. This is demonstrated for magnesia stabilized zirconia, where very good predictions are obtained using an estimate of this single parameter. On the basis of this model, relations between the material removal rate and the controllable machining parameters are deduced. These relationships agree well with the trends observed by experimental observations made by other investigators.

Machinability Evaluation in the Ultrasonic Drilling (USD) Process of Aluminum Oxide-based Ceramics

2011 ◽  
Vol 223 ◽  
pp. 804-812
Author(s):  
R. S. Jadoun
Keyword(s):  
Aluminum Oxide ◽  
Mathematical Models ◽  
Removal Rate ◽  
Ceramic Materials ◽  
Performance Characteristics ◽  
Machining Parameters ◽  
Ultrasonic Drilling ◽  
The Face ◽  
Face Centered ◽  
Central Composite

The ultrasonic drilling (USD) has been used in the manufacture of the hard, fragile, difficult to cut, nonconductive ceramic materials. In this study, the mathematical models of material removal rate (MRR) and surface roughness (SR) have been obtained for the machinability evaluation in the USD process of aluminum oxide-based ceramic material. The experimental plan adopts the face centered central composite design (CCD). The mathematical models using the response surface methodology (RSM) are developed so as to investigate the influences of three machining parameters, including the power rating, grit size and slurry concentration on the performance characteristics of MRR and SR. It has been proved that the proposed mathematical models in this study would fit and predict values of the performance characteristics, which would be close to the readings recorded in experiment with a 95% confidence level. The significant parameters that critically affect the performance characteristics are examined.

Metallic reinforcements role on aluminum silicon composites wear behavior

2016 ◽  
Vol 51 (19) ◽  
pp. 2805-2812 ◽  
Author(s):  
G Miranda ◽  
M Buciumeanu ◽  
MM Costa ◽  
F Bartolomeu ◽  
FS Silva ◽  
...  
Keyword(s):  
Cast Iron ◽  
Gray Cast Iron ◽  
Wear Behavior ◽  
Microstructural Characterization ◽  
Gray Cast ◽  
Wear Performance ◽  
Particulate Reinforced Composites ◽  
Particulate Reinforced ◽  
Wear Tests ◽  
Aluminum Silicon

This study is concerned with the influence of four metallic reinforcements on aluminum-silicon (AlSi) composites, with respect to wear behavior. AlSi-Ti; AlSi-Ti6Al4V; AlSi-1.4301 stainless steel and AlSi-Ni particulate reinforced composites were produced by a hot-pressing route. Microstructural characterization showed a uniform distribution of the reinforcing particles in the AlSi matrix. Reciprocating pin-on-plate wear tests were performed for AlSi and AlSi-based composites against gray cast iron plates. In order to compare the effect of different metallic particulates on the AlSi-based composites/gray cast iron tribopair wear performance, besides the pin, the counterface was also analyzed. The particle/matrix interface is analyzed in order to understand its influence on the tribopair behavior and on the controlling wear mechanisms. It was shown that the better compromise between both sliding surfaces performance was attained by AlSi-Ni/gray cast iron tribopair.

scholarly journals Role of abrasive material on micro-abrasion wear tests

Wear ◽  
2011 ◽  
Vol 271 (9-10) ◽  
pp. 2632-2639 ◽  
Author(s):  
F.J.G. Silva ◽  
R.B. Casais ◽  
R.P. Martinho ◽  
A.P.M. Baptista
Keyword(s):  
Abrasive Material ◽  
Abrasion Wear ◽  
Wear Tests

scholarly journals Synaptic transistors with aluminum oxide dielectrics enabling full audio frequency range signal processing

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sami Bolat ◽  
Galo Torres Sevilla ◽  
Alessio Mancinelli ◽  
Evgeniia Gilshtein ◽  
Jordi Sastre ◽  
...  
Keyword(s):  
Signal Processing ◽  
Aluminum Oxide ◽  
Electronic Devices ◽  
Rapid Evolution ◽  
Future Research ◽  
Acoustic Response ◽  
Oxide Electronics ◽  
Wide Range ◽  
Input Signals ◽  
Chemical Synapses

Abstract The rapid evolution of the neuromorphic computing stimulates the search for novel brain-inspired electronic devices. Synaptic transistors are three-terminal devices that can mimic the chemical synapses while consuming low power, whereby an insulating dielectric layer physically separates output and input signals from each other. Appropriate choice of the dielectric is crucial in achieving a wide range of operation frequencies in these devices. Here we report synaptic transistors with printed aluminum oxide dielectrics, improving the operation frequency of solution-processed synaptic transistors by almost two orders of magnitude to 50 kHz. Fabricated devices, yielding synaptic response for all audio frequencies (20 Hz to 20 kHz), are employed in an acoustic response system to show the potential for future research in neuro-acoustic signal processing with printed oxide electronics.

scholarly journals Spraying of Viscous Liquids: Influence of Fluid-Mixing Mechanism on the Performance of Internal-Mixing Twin-Fluid Atomizers

2020 ◽  
Vol 10 (15) ◽  
pp. 5249
Author(s):  
Marek Mlkvik ◽  
Jan Jedelsky ◽  
Heike P. Karbstein ◽  
Volker Gaukel
Keyword(s):  
Optical Diffraction ◽  
Liquid Fuels ◽  
Liquid Viscosity ◽  
Two Phase ◽  
Internal Mixing ◽  
Mixing Chamber ◽  
Wide Range ◽  
Effervescent Atomizer ◽  
The Common ◽  
Jet Nozzle

The thermal usage of liquid fuels implies their combustion, which is a process strongly influenced by the performance of the atomizer, which disrupts the fuel into drops of the required sizes. The spray quality of the twin-fluid atomizers with internal mixing (IM-TFA) is primarily influenced by the two-phase flow pattern inside the mixing chamber. We studied the performance of the four types of the IM-TFA nozzles by the optical diffraction system (Malvern Spraytec) to answer the question of how the mixing chamber design influences the spray quality at low atomizing gas consumption. We tested the effervescent atomizer in outside-in-liquid (OIL) and outside-in-gas (OIG) configurations, the Y-jet nozzle and new nozzle design, and the CFT atomizer when spraying model liquids with the viscosities comparable to the common fuels (μ=60and143 mPa· s). We found that the effervescent atomizer performance was strongly influenced by the configuration of the inlet ports. Although the OIL configuration provided the best spray quality (D32 = 72 μm), with the highest efficiency (0.16%), the OIG nozzle was characterized by unstable work and poor spray quality. Both the devices were sensitive to liquid viscosity. The Y-jet nozzle provided a stable performance over the liquid viscosity spectrum, but the spray quality and efficiency were lower than for the OIL nozzle. Our findings can be used to improve the performance of the common IM-TFA types or to design new atomizers. The results also provide an overview of the tested atomizers’ performances over the wide range of working conditions and, thus, help to define the application potential of the tested nozzle designs.

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