scholarly journals Principles and Characteristics of Different EDM Processes in Machining Tool and Die Steels

2020 ◽  
Vol 10 (6) ◽  
pp. 2082 ◽  
Author(s):  
Jaber E. Abu Qudeiri ◽  
Aiman Zaiout ◽  
Abdel-Hamid I. Mourad ◽  
Mustufa Haider Abidi ◽  
Ahmed Elkaseer
Keyword(s):  
Large Scale ◽  
Removal Rate ◽  
Surface Characteristics ◽  
Future Research ◽  
Process Conditions ◽  
Process Performance ◽  
Die Steels ◽  
Wide Range ◽  
Complex Shapes ◽  
Manufacturing Technologies

Electric discharge machining (EDM) is one of the most efficient manufacturing technologies used in highly accurate processing of all electrically conductive materials irrespective of their mechanical properties. It is a non-contact thermal energy process applied to a wide range of applications, such as in the aerospace, automotive, tools, molds and dies, and surgical implements, especially for the hard-to-cut materials with simple or complex shapes and geometries. Applications to molds, tools, and dies are among the large-scale initial applications of this process. Machining these items is especially difficult as they are made of hard-to-machine materials, they have very complex shapes of high accuracy, and their surface characteristics are sensitive to machining conditions. The review of this kind with an emphasis on tool and die materials is extremely useful to relevant professions, practitioners, and researchers. This review provides an overview of the studies related to EDM with regard to selection of the process, material, and operating parameters, the effect on responses, various process variants, and new techniques adopted to enhance process performance. This paper reviews research studies on the EDM of different grades of tool steel materials. This article (i) pans out the reported literature in a modular manner with a focus on experimental and theoretical studies aimed at improving process performance, including material removal rate, surface quality, and tool wear rate, among others, (ii) examines evaluation models and techniques used to determine process conditions, and (iii) discusses the developments in EDM and outlines the trends for future research. The conclusion section of the article carves out precise highlights and gaps from each section, thus making the article easy to navigate and extremely useful to the related research community.

scholarly journals Advanced Electric Discharge Machining of Stainless Steels: Assessment of the State of the Art, Gaps and Future Prospect

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 907 ◽  
Author(s):  
Jaber Abu Qudeiri ◽  
Ahmad Saleh ◽  
Aiman Ziout ◽  
Abdel-Hamid Mourad ◽  
Mustufa Abidi ◽  
...  
Keyword(s):  
Electric Discharge ◽  
Material Removal ◽  
Removal Rate ◽  
Future Research ◽  
Process Conditions ◽  
Process Performance ◽  
Electric Discharge Machining ◽  
Electrically Conductive ◽  
Complex Shapes ◽  
Efficient Manufacturing

Electric discharge machining (EDM) is a material removal process that is especially useful for difficult-to-cut materials with complex shapes and is widely used in aerospace, automotive, surgical tools among other fields. EDM is one of the most efficient manufacturing processes and is used to achieve highly accurate production. It is a non-contact thermal energy process used to machine electrically conductive components irrespective of the material’s mechanical properties. Studies related to the EDM have shown that the process performance can be considerably improved by properly selecting the process material and operating parameters. This paper reviews research studies on the application of EDM to different grades of stainless steel materials and describes experimental and theoretical studies of EDM that have attempted to improve the process performance, by considering material removal rate, surface quality and tool wear rate, amongst others. In addition, this paper examines evaluation models and techniques used to determine the EDM process conditions. This review also presents a discussion on developments in EDM and outlines the likely trend for future research.

scholarly journals Enhanced Wastewater Treatment by Immobilized Enzymes

2021 ◽  
Author(s):  
Jakub Zdarta ◽  
Katarzyna Jankowska ◽  
Karolina Bachosz ◽  
Oliwia Degórska ◽  
Karolina Kaźmierczak ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Process Optimization ◽  
Organic Pollutants ◽  
Large Scale ◽  
Removal Rate ◽  
Immobilized Enzymes ◽  
Future Research ◽  
Process Conditions ◽  
Removal Rates ◽  
Catalytic Cycles

Abstract Purpose of Review In the presented review, we have summarized recent achievements on the use of immobilized oxidoreductases for biodegradation of hazardous organic pollutants including mainly dyes, pharmaceuticals, phenols, and bisphenols. In order to facilitate process optimization and achievement of high removal rates, effect of various process conditions on biodegradation has been highlighted and discussed. Recent Findings Current reports clearly show that immobilized oxidoreductases are capable of efficient conversion of organic pollutants, usually reaching over 90% of removal rate. Further, immobilized enzymes showed great recyclability potential, allowing their reuse in numerous of catalytic cycles. Summary Collected data clearly indicates immobilized oxidoreductases as an efficient biocatalytic tools for removal of hazardous phenolic compounds, making them a promising option for future water purification. Data shows, however, that both immobilization and biodegradation conditions affect conversion efficiency; therefore, process optimization is required to achieve high removal rates. Nevertheless, we have demonstrated future trends and highlighted several issues that have to be solved in the near-future research, to facilitate large-scale application of the immobilized oxidoreductases in wastewater treatment.

Electron microscopy study of reactively sputter-deposited Ti/N films on silicon

1992 ◽  
Vol 50 (2) ◽  
pp. 1362-1363
Author(s):  
V. C. Kannan ◽  
A. K. Singh ◽  
R. B. Irwin ◽  
S. Chittipeddi ◽  
F. D. Nkansah ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Large Scale ◽  
Hexagonal Phase ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Process Conditions ◽  
Tin Films ◽  
Wide Range ◽  
Fcc Phase ◽  
Circuits Vlsi

Titanium nitride (TiN) films have historically been used as diffusion barrier between silicon and aluminum, as an adhesion layer for tungsten deposition and as an interconnect material etc. Recently, the role of TiN films as contact barriers in very large scale silicon integrated circuits (VLSI) has been extensively studied. TiN films have resistivities on the order of 20μ Ω-cm which is much lower than that of titanium (nearly 66μ Ω-cm). Deposited TiN films show resistivities which vary from 20 to 100μ Ω-cm depending upon the type of deposition and process conditions. TiNx is known to have a NaCl type crystal structure for a wide range of compositions. Change in color from metallic luster to gold reflects the stabilization of the TiNx (FCC) phase over the close packed Ti(N) hexagonal phase. It was found that TiN (1:1) ideal composition with the FCC (NaCl-type) structure gives the best electrical property.

scholarly journals Taming the chaos: NHS professionals’ perspective of using video consulting during COVID-19 in Wales

2021 ◽  
Vol 10 (4) ◽  
pp. e001318
Author(s):  
Gemma Johns ◽  
Sara Khalil ◽  
Mike Ogonovsky ◽  
Markus Hesseling ◽  
Allan Wardhaugh ◽  
...  
Keyword(s):  
National Health Service ◽  
Large Scale ◽  
Future Research ◽  
Local Health ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Wide Range ◽  
Early Use ◽  
Observational Study Design ◽  
The Uk

The use of video consulting (VC) in the UK has expanded rapidly during the COVID-19 pandemic. Technology Enabled Care (TEC) Cymru, the Welsh Government and Local Health boards began implementing the National Health Service (NHS) Wales VC Service in March 2020. This has been robustly evaluated on a large-scale All-Wales basis, across a wide range of NHS Wales specialities.AimsTo understand the early use of VC in Wales from the perspective of NHS professionals using it. NHS professionals were approached by TEC Cymru to provide early data.MethodsUsing an observational study design with descriptive methods including a cross-sectional survey, TEC Cymru captured data on the use, benefits and challenges of VC from NHS professionals in Wales during August and September 2020. This evidence is based on the rapid adoption of VC in Wales, which mirrors that of other nations.ResultsA total of 1256 NHS professionals shared their VC experience. Overall, responses were positive, and professionals expressed optimistic views regarding the use and benefit of VC, even when faced with challenges on occasions.ConclusionsThis study provides evidence of general positivity, acceptance and the success of the VC service in Wales. Future research studies will now be able to explore and evaluate the implementation methods used within this study, and investigate their effectiveness in being able to achieve better outcomes through VC.

scholarly journals Ephemeral Architectures: the union of concepts in the creation of an immersive experience

2020 ◽  
pp. 38-39
Author(s):  
Paula Arzillo ◽  
Marcus Vinicius Pereira
Keyword(s):  
Large Scale ◽  
Graphical Representation ◽  
Parametric Design ◽  
Three Dimensional ◽  
Computer Software ◽  
Future Research ◽  
Digital Architecture ◽  
Spider Web ◽  
Complex Shapes ◽  
The Creation

This theoretical-methodological research aims a final graduation paper in the Architectures and Urbanism bachelor’s degree program, which corresponds to an activity of synthesis and integration of skills developed throughout the course. Therefore, it is proposed to create a Project of an ephemeral architecture, which explores the perception and sensitivity of visitors, through the interactive experiences given by it. The theoretical basis searches architectural practices that relate innovative Technologies, and which materialize through an immersive exhibition, which explores interactivity with the visitors, in order to stimulate human senses – such as touch, smell, taste and hearing. For this, it is taken advantage of organic shape study, relating the concepts of biomimetic design and parametric design in order to demystify complex formulas through computer generated algorithms. The evolution process of the new digital tools brings an approximation of graphical representation with the real world. The complexity of the architectural technical representation, reached a parameter that becomes impossible without the computer software. In this context, parametric architecture is a technique developed from software, which has the ability to perform complex calculations, in a clear and effective way, allowing the creation of complex shapes that allow to expand the creative process until then, limited by technical characteristics. The Project called “Feelings, an immersive experience is made up of six distinct spaces, divides by rooms for temporary exhibitions at the Pinacoteca do Estado de São Paulo. The beginning of the Project route is given by the central octagon, where is thefirst installation that has a large scale, inspired by a spider web materialized through tensioned lycra fabric. The others rooms are based on the shape and characteristics of animals: 1) the Octopus tentacles, which stimulate the human touch, through holes in the Octopus suckers, that invite visitors to find out different textures; 2) butterfly cocoons shapes, containing aromas capsules, which stimulate the sense of smell; 3) silhouettes of marine jellyfish shelter the dripping system of a surprise flavor drop, which awaken the taste buds, sensory receptors of the tongue as sweet, bitter, salty, sours or umami; 4) the chameleon’s scalyskin, due to the ability to change colors, is taken to produce an interactive panel of lights that stimulates the sense of vision; 5) the structure of bird s taken to address the sense of hearing, by hiding speakers with sound effects that change according to the visitors interaction. All the structuring of these models used practices of digital architecture technologies. Finally, this research applies practical solutions based on three-dimensional graphic models for the representation of projects with complex shapes through intensive use of modeling, standing out for uniting concepts such as biomimetics and parametric in favor of the practice of innovative tools and still not so much explored in the Architecture and Urbanism course, promoting future research and expanding the repertoire within the area.

scholarly journals Critical Analysis of Parallel and Distributed Computing and Future Research Direction of Cloud Computing

2021 ◽  
pp. 114-120
Author(s):  
Rimma Padovano
Keyword(s):  
Cloud Computing ◽  
Distributed Computing ◽  
Large Scale ◽  
Research Direction ◽  
Future Research ◽  
Parallel And Distributed Computing ◽  
Research Technology ◽  
Wide Range ◽  
High Level ◽  
Computer Resources

"Cloud computing" refers to large-scale parallel and distributed systems, which are essentially collections of autonomous. As a result, the “cloud organization” is made up on a wide range of ideas and experiences collected since the first digital computer was used to solve algorithmically complicated problems. Due to the complexity of established parallel and distributed computing ontologies, it is necessary for developers to have a high level of expertise to get the most out of the consolidated computer resources. The directions for future research for parallel and distributed computing are critically presented in this research: technology and application and cross-cutting concerns.

Restoration of Seagrasses: With Economic Analysis

1976 ◽  
Vol 3 (4) ◽  
pp. 259-266 ◽  
Author(s):  
Anitra Thorhaug ◽  
C. Bruce Austin
Keyword(s):  
Large Scale ◽  
Donor Site ◽  
Future Research ◽  
Important Species ◽  
Seagrass Community ◽  
Long Run ◽  
Seeding Method ◽  
Practical Operation ◽  
Wide Range ◽  
Marine Areas

The technique of restoration of populations of land plants is an old one that is well understood by scientists, agronomists, forestry experts, and the general public. However, only recently has attention been turned to restoring underwater areas with socalled seagrasses. From 1947 onwards, attempts have been made to restore suitable marine areas by using important species; however, only very recently (from August 1973) have large-scale restoration projects been undertaken.The efforts that have been made to replant various seagrass species by different techniques are reviewed, but only two seagrasses, Zostera noltii and Thalassia testudinum, have been restored on a large scale. Both of these can be restored successfully; however, the seeding method of Thalassia appears to be the most practical operation of all, and the most potentially valuable for future research into large-scale restoration, as it allows flexibility of location and of depth of transplantation, and involves the minimum of damage to the donor site. It also ensures the most rapid regrowth, besides being in the long run the most economical method yet devised of restoring a seagrass community. An economic model (see Technical Appendix to this paper) and analysis for restoration costs are given and finally a wide range of uses of restoration of such beds of seagrasses are enumerated.

Governing education in times of crisis: State interventions and school accountabilities during the COVID-19 pandemic

2021 ◽  
pp. 147490412110221
Author(s):  
Alison L. Milner ◽  
Paola Mattei ◽  
Christian Ydesen
Keyword(s):  
Large Scale ◽  
Institutional Logics ◽  
Future Research ◽  
Policy Reforms ◽  
Structured Interviews ◽  
Government Interventions ◽  
Professional Accountability ◽  
Wide Range ◽  
State Interventions ◽  
Modes Of Governance

Strategic government interventions in public education have shifted and blurred the boundaries between state, market and civil society modes of governance. Within this matrix of interdependent relations, schools operate under increasingly hybrid accountability arrangements in which public accountability can both complement and compete with market and social regimes and their associated institutional logics, goals, values and mechanisms. During the first wave of the COVID-19 pandemic, however, national governments implemented a wide range of emergency measures which had consequences for the mixes and layers of school accountabilities. This article examines the principal policy changes in Denmark, England and Italy. Drawing on state theories and the concept of ‘hybrid accountability’, semi-structured interviews with national and local policymakers and school practitioners were analysed thematically. While cultural nuances exist between the cases, our findings reveal that state interventions reinforce a public–professional accountability hybrid and hierarchies of control and command within and outside networks. Concomitantly, state non-interventions and the distinct underlying institutional logics associated with national large-scale assessments suggest policy inertia with implications for professional accountability and institutionalised change. Future research might investigate whether educators’ experiences influence the direction of national and local accountability policy reforms in a post-pandemic era.

Bias in Context: Small Biases in Hiring Evaluations Have Big Consequences

2021 ◽  
pp. 014920632098265
Author(s):  
Jay H. Hardy ◽  
Kian Siong Tey ◽  
Wilson Cyrus-Lai ◽  
Richard F. Martell ◽  
Andy Olstad ◽  
...  
Keyword(s):  
Gender Bias ◽  
Large Scale ◽  
Meta Analysis ◽  
Productivity Loss ◽  
Future Research ◽  
Hiring Managers ◽  
Hiring Discrimination ◽  
Wide Range ◽  
The Impact ◽  
Practical Impact

It is widely acknowledged that subgroup bias can influence hiring evaluations. However, the notion that bias still threatens equitable hiring outcomes in modern employment contexts continues to be debated, even among organizational scholars. In this study, we sought to contextualize this debate by estimating the practical impact of bias on real-world hiring outcomes (a) across a wide range of hiring scenarios and (b) in the presence of diversity-oriented staffing practices. Toward this end, we conducted a targeted meta-analysis of recent hiring experiments that manipulated both candidate gender and qualifications to couch our investigation within ongoing debates surrounding the impact of small amounts of bias in otherwise meritocratic hiring contexts. Consistent with prior research, we found evidence of small gender bias effects ( d = −0.30) and large qualification effects ( d = 1.61) on hiring managers’ evaluations of candidate hireability. We then used these values to inform the starting parameters of a large-scale computer simulation designed to model conventional processes by which candidates are recruited, evaluated, and selected for open positions. Collectively, our simulation findings empirically substantiate assertions that even seemingly trivial amounts of subgroup bias can produce practically significant rates of hiring discrimination and productivity loss. Furthermore, we found contextual factors can alter but cannot obviate the consequences of biased evaluations, even within apparently optimal hiring scenarios (e.g., when extremely valid assessments are used). Finally, our results demonstrate residual amounts of subgroup bias can undermine the effectiveness of otherwise successful targeted recruitment efforts. Implications for future research and practice are discussed.

scholarly journals Process Evaluation of Recombinant Chitin Deacetylase Expression in E. Coli Rosetta pLysS Cells using Statistical Design of Experiments

2021 ◽  
Author(s):  
Goutam Mohan Pawaskar ◽  
Ritu Raval ◽  
Subbalaxmi S
Keyword(s):  
Large Scale ◽  
Statistical Design ◽  
Fold Increase ◽  
Process Conditions ◽  
Scale Production ◽  
Statistical Design Of Experiments ◽  
Chitin Deacetylase ◽  
E Coli ◽  
Nutritional Conditions ◽  
Wide Range

Abstract Chitin is a natural polymer with N-acetylglucosamine units, extracted from seafood waste as a major source. It remains an underexplored polymer due to its crystalline structure. The commercial applicability can be improved if we could make it soluble. One of the routes employed to decrease this crystallinity is the conversion of chitin to chitosan via deacetylation. The industrial production of chitosan uses chemical methods, which leaves the process footprint on the environment. The greener alternative approach to producing chitosan is using chitin deacetylases (CDA). The enzymatically converted chitosan with known characteristics has a wide range of applications, importantly in the biomedical field. In the present paper, we report heterologous expression of CDA from a marine moneran; Bacillus aryabhattai B8W22. The process and the nutritional conditions were optimized for the submerged fermentation condition of E. coli Rosetta pLysS expressing the recombinant CDA using the design of experiment tools. The employment of central composite design (CCD) resulted in a ~2.39 fold increase in the total activity of expressed CDA with the process conditions of induction temperature at 22 ºC, agitation at 120 rpm, and 30 h of fermentation. The nutritional conditions required for the optimized expression were 0.061% glucose concentration and 1% lactose in media. The employment of these optimal growth conditions could result in cost-effective large-scale production of the lesser-explored moneran deacetylase, embarking on the greener route to produce biomedical grade chitosan.

Sign in / Sign up

Export Citation Format

Share Document