scholarly journals Novel three-body nano-abrasive wear mechanism

Friction ◽  
2021 ◽  
Author(s):  
Ruling Chen ◽  
Shaoxian Li
Keyword(s):  
Abrasive Wear ◽  
Material Removal ◽  
Crystalline Silicon ◽  
Surface Damage ◽  
Mating Surface ◽  
Dynamics Simulations ◽  
New Research ◽  
Three Body ◽  
The Relationship ◽  
Material Wear

AbstractCurrent three-body abrasive wear theories are based on a macroscale abrasive indentation process, and these theories claim that material wear cannot be achieved without damaging the hard mating surface. In this study, the process of three-body nano-abrasive wear of a system including a single crystalline silicon substrate, an amorphous silica cluster, and a polyurethane pad, based on a chemical mechanical polishing (CMP) process, is investigated via molecular dynamics simulations. The cluster slid in a suspended state in smooth regions and underwent rolling impact in the asperity regions of the silicon surface, realizing non-damaging monoatomic material removal. This proves that indentation-plowing is not necessary when performing CMP material removal. Therefore, a non-indentation rolling-sliding adhesion theory for three-body nano-abrasive wear between ultrasoft/hard mating surfaces is proposed. This wear theory not only unifies current mainstream CMP material removal theories, but also clarifies that monoatomic material wear without damage can be realized when the indentation depth is less than zero, thereby perfecting the relationship between material wear and surface damage. These results provide new understanding regarding the CMP microscopic material removal mechanism as well as new research avenues for three-body abrasive wear theory at the monoatomic scale.

Experimental Study on Micro-Nano Scratching of Mono-Crystalline Silicon Wafer

2010 ◽  
Vol 135 ◽  
pp. 458-461
Author(s):  
Xin Wei ◽  
Zhuo Chen ◽  
Xiao Zhu Xie ◽  
Qing Lei Ren
Keyword(s):  
Silicon Wafer ◽  
Material Removal ◽  
Crystalline Silicon ◽  
Material Removal Mechanism ◽  
Crystal Silicon ◽  
Constant Loading ◽  
Elastic Regime ◽  
Loading Methods ◽  
The Relationship ◽  
Ductile Removal

In this paper, micro-nano scratching experiments were conducted on mono-crystalline silicon wafer to investigate the material removal mechanism of silicon. Two loading methods (increasing-loading and constant-loading) were used. The characteristics of the scratching grooves, and the relationship between the groove size and the load were analyzed by observing the surface torography and measuring the groove. The results show that there are four distinct regimes existed with an increasing scratching load: elastic regime, ductile regime, ductile-brittle regime and brittle regime. The critical load of the transition from ductile to ductile-brittle regime can be considered as 120mN, within which smooth scratching surfaces have been obtained by ductile removal. The scratching load has very significant effects on the groove sizes of the mono-crystal silicon.

INNOVATION CAPABILITY, ABSORPTIVE CAPACITY AND SMES PERFORMANCE IN PAKISTAN: THE MODERATING EFFECT OF BUSINESS STRATEGY

2018 ◽  
Vol 13 (Number 2) ◽  
pp. 1-11
Author(s):  
Muhammad Zulqarnain Arshad ◽  
Darwina Arshad
Keyword(s):  
Economic Growth ◽  
Absorptive Capacity ◽  
Business Strategy ◽  
Innovation Capability ◽  
Research Directions ◽  
Conceptual Paper ◽  
And Performance ◽  
New Research ◽  
The Relationship ◽  
Crucial Part

The small and medium-sized enterprises (SMEs) play a crucial part in county’s economic growth and a key contributor in country’s GDP. In Pakistan SMEs hold about 90 percent of the total businesses. The performance of SMEs depends upon many factors. The main aim for the research is to examine the relationship between Innovation Capability, Absorptive Capacity and Performance of SMEs in Pakistan. This conceptual paper also extends to the vague revelation on Business Strategy in which act as a moderator between Innovation Capability, Absorptive Capacity and SMEs Performance. Conclusively, this study proposes a new research directions and hypotheses development to examine the relationship among the variables in Pakistan’s SMEs context.

FBI and Religion

2017 ◽  
Keyword(s):  
Religious Orientation ◽  
Religious Communities ◽  
Academic Scholarship ◽  
History Of ◽  
Interdisciplinary Assessment ◽  
Civic Religion ◽  
New Research ◽  
The Relationship ◽  
The Way

This volume is an interdisciplinary assessment of the relationship between religion and the FBI. We recount the history of the FBI’s engagement with multiple religious communities and with aspects of public or “civic” religion such as morality and respectability. The book presents new research to explain roughly the history of the FBI’s interaction with religion over approximately one century, from the pre-Hoover period to the post-9/11 era. Along the way, the book explores vexed issues that go beyond the particulars of the FBI’s history—the juxtaposition of “religion” and “cult,” the ways in which race can shape the public’s perceptions of religion (and vica versa), the challenges of mediating between a religious orientation and a secular one, and the role and limits of academic scholarship as a way of addressing the differing worldviews of the FBI and some of the religious communities it encounters.

The influence of ultrasound signal parameters on sonoluminescence light intensity

2013 ◽  
Vol 62 (4) ◽  
pp. 605-612
Author(s):  
Marek Szmechta ◽  
Tomasz Boczar ◽  
Dariusz Zmarzły
Keyword(s):  
Acoustic Emission ◽  
Acoustic Waves ◽  
Power Transformer ◽  
Electrical Power ◽  
Partial Discharges ◽  
Research Project ◽  
Insulation Systems ◽  
Secondary Phenomenon ◽  
New Research ◽  
The Relationship

Abstract Topics of this article concern the study of the fundamental nature of the sonoluminescence phenomenon occurring in liquids. At the Institute of Electrical Power Engineering at Opole University of Technology the interest in that phenomenon known as secondary phenomenon of cavitation caused by ultrasound became the genesis of a research project concerning acoustic cavitation in mineral insulation oils in which a number of additional experiments performed in the laboratory aimed to determine the influence of a number of acoustic parameters on the process of the studied phenomenona. The main purpose of scientific research subject undertaken was to determine the relationship between the generation of partial discharges in high-voltage power transformer insulation systems, the issue of gas bubbles in transformer oils and the generated acoustic emission signals. It should be noted that currently in the standard approach, the phenomenon of generation of acoustic waves accompanying the occurrence of partial discharges is generally treated as a secondary phenomenon, but it can also be a source of many other related phenomena. Based on our review of the literature data on those referred subjects taken, it must be noted, that this problem has not been clearly resolved, and the description of the relationship between these phenomena is still an open question. This study doesn’t prove all in line with the objective of the study, but can be an inspiration for new research project in the future in this topic. Solution of this problem could be a step forward in the diagnostics of insulation systems for electrical power devices based on non-invasive acoustic emission method.

Modeling and Analyzing on Nonuniformity of Material Removal in Chemical Mechanical Polishing of Silicon Wafer

2004 ◽  
Vol 471-472 ◽  
pp. 26-31 ◽  
Author(s):  
Jian Xiu Su ◽  
Dong Ming Guo ◽  
Ren Ke Kang ◽  
Zhu Ji Jin ◽  
X.J. Li ◽  
...  
Keyword(s):  
Silicon Wafer ◽  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Mechanical Polishing ◽  
Wafer Surface ◽  
Removal Mechanism ◽  
Particle Movement ◽  
Material Removal Mechanism ◽  
The Relationship ◽  
Nonuniform Material

Chemical mechanical polishing (CMP) has already become a mainstream technology in global planarization of wafer, but the mechanism of nonuniform material removal has not been revealed. In this paper, the calculation of particle movement tracks on wafer surface was conducted by the motion relationship between the wafer and the polishing pad on a large-sized single head CMP machine. Based on the distribution of particle tracks on wafer surface, the model for the within-wafer-nonuniformity (WIWNU) of material removal was put forward. By the calculation and analysis, the relationship between the motion variables of the CMP machine and the WIWNU of material removal on wafer surface had been derived. This model can be used not only for predicting the WIWNU, but also for providing theoretical guide to the design of CMP equipment, selecting the motion variables of CMP and further understanding the material removal mechanism in wafer CMP.

scholarly journals Pervasive cooperative mutational effects on multiple catalytic enzyme traits emerge via long-range conformational dynamics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Carlos G. Acevedo-Rocha ◽  
Aitao Li ◽  
Lorenzo D’Amore ◽  
Sabrina Hoebenreich ◽  
Joaquin Sanchis ◽  
...  
Keyword(s):  
Long Range ◽  
Fitness Landscape ◽  
Conformational Dynamics ◽  
P450 Monooxygenase ◽  
Access Channel ◽  
Long Range Interactions ◽  
Limited Protein ◽  
Dynamics Simulations ◽  
The Relationship ◽  
Single Enzyme

AbstractMultidimensional fitness landscapes provide insights into the molecular basis of laboratory and natural evolution. To date, such efforts usually focus on limited protein families and a single enzyme trait, with little concern about the relationship between protein epistasis and conformational dynamics. Here, we report a multiparametric fitness landscape for a cytochrome P450 monooxygenase that was engineered for the regio- and stereoselective hydroxylation of a steroid. We develop a computational program to automatically quantify non-additive effects among all possible mutational pathways, finding pervasive cooperative signs and magnitude epistasis on multiple catalytic traits. By using quantum mechanics and molecular dynamics simulations, we show that these effects are modulated by long-range interactions in loops, helices and β-strands that gate the substrate access channel allowing for optimal catalysis. Our work highlights the importance of conformational dynamics on epistasis in an enzyme involved in secondary metabolism and offers insights for engineering P450s.

Tribological Properties of Calotropis Procera Natural Fiber Reinforced Hybrid Epoxy Composites

2019 ◽  
Vol 895 ◽  
pp. 45-51
Author(s):  
M.J. Raghu ◽  
Govardhan Goud
Keyword(s):  
Abrasive Wear ◽  
Glass Fibre ◽  
Sliding Wear ◽  
Natural Fiber ◽  
Wear Test ◽  
Calotropis Procera ◽  
Dry Sliding Wear ◽  
Wear Loss ◽  
Fiber Reinforced ◽  
Three Body

Natural fibers are widely used for reinforcement in polymer composite materials and proved to be effectively replacing synthetic fiber reinforced polymer composites to some extent in applications like domestic, automotive and lower end aerospace parts. The natural fiber reinforced composites are environment friendly, have high strength to weight ratio as well as specific strengths comparable with synthetic glass fiber reinforced composites. In the present work, hybrid epoxy composites were fabricated using calotropis procera and glass fibers as reinforcement by hand lay-up method. The fibre reinforcement in epoxy matrix was maintained at 20 wt%. In 20 wt% reinforcement of fibre, the content of calotropis procera and glass fibre were varied from 5, 10, 15 and 20 wt%. The dry sliding wear test as per ASTM G99 and three body abrasive wear test as per ASTM G65 were conducted to find the tribological properties by varying speed, load, distance and abrasive size. The hybrid composite having 5 wt% calotropis procera and 15 wt% glass fibre showed less wear loss in hybrid composites both in sliding wear test as well as in abrasive wear test which is comparable with 20 wt% glass fibre reinforced epoxy composite which marked very low wear loss. The SEM analysis was carried out to study the worn out surfaces of dry sliding wear test and three body abrasive wear test specimens.

High temperature three-body abrasive wear of 0.25C 1.42Si steel with carbide free bainitic (CFB) and martensitic microstructures

Wear ◽  
2016 ◽  
Vol 360-361 ◽  
pp. 21-28 ◽  
Author(s):  
Sinuhe Hernandez ◽  
Alejandro Leiro ◽  
Manel Rodríguez Ripoll ◽  
Esa Vuorinen ◽  
Karl-Gustaf Sundin ◽  
...  
Keyword(s):  
High Temperature ◽  
Abrasive Wear ◽  
Three Body

Investigation of the Water Guided Laser Micro-Jet Machining of Aero Engine Components

2017 ◽  
Author(s):  
Zhigang Wang
Keyword(s):  
Energy Density ◽  
Material Removal ◽  
Removal Rate ◽  
Cutting Speed ◽  
Potential Method ◽  
Laser Machining ◽  
Aero Engine ◽  
Engine Components ◽  
The Relationship ◽  
Dual Laser

The water guided laser micro-jet (LMJ) is a new potential method to machine aero engine parts with much less heat affected area and faster cutting speed than dry laser machining. The focus of this paper is to investigate the energy density and material removal for a dual-laser LMJ system. Then, the effects of dominated parameters on the energy density of LMJ are analyzed. Finally, a mathematical model is developed to describe the relationship between dominant laser parameters with the energy density of LMJ and material removal rate followed by machining case studies of aero engine components.

Chemically Assisted Machining of Ceramics

1994 ◽  
Vol 116 (3) ◽  
pp. 423-429 ◽  
Author(s):  
J. C. Wang ◽  
S. M. Hsu
Keyword(s):  
Material Removal ◽  
Removal Rate ◽  
High Hardness ◽  
Chemical Compounds ◽  
Surface Damage ◽  
Diamond Wheel ◽  
Halogenated Hydrocarbons ◽  
Ceramic Machining ◽  
Machining Of Ceramics ◽  
Machining Fluids

Ceramics are hard and brittle. Machining such materials is time-consuming, difficult, and expensive. Current machining technology requires stiff machine, high hardness tools, and small material removal rates to minimize surface damage. This study demonstrates the feasibility of a novel ceramic machining concept that utilizes chemical reactions at the tool-workpiece interface to reduce the stress and minimize the surface damage. A series of cutting tests using a diamond wheel on silicon nitride with different chemical compounds has been performed. The results demonstrate that by using different chemistries, the material removal rate and the surface finish of the machined ceramic can be significantly altered. Some halogenated hydrocarbons show a significant improvement over some commercial machining fluids currently in use.

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