scholarly journals A Review on Binderless Tungsten Carbide: Development and Application

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Jialin Sun ◽  
Jun Zhao ◽  
Zhifu Huang ◽  
Ke Yan ◽  
Xuehui Shen ◽  
...  
Keyword(s):  
Tungsten Carbide ◽  
High Performance ◽  
Current Knowledge ◽  
Electrical Contacts ◽  
Practical Significance ◽  
Sintering Behavior ◽  
Mechanical Seals ◽  
Environment Friendly ◽  
Price Instability ◽  
Processing Techniques

AbstractWC-Co alloys have enjoyed great practical significance owing to their excellent properties during the past decades. Despite the advantages, however, recently there have been concerns about the challenges associated with the use of Co, i.e. price instability, toxicity and properties degeneration, which necessitates the fabrication of binderless tungsten carbide (BTC). On the other hand, BTC or BTC composites, none of them, to date has been commercialized and produced on an industrial scale, but only used to a limited extent for specialized applications, such as mechanical seals undergoing high burthen as well as high temperature electrical contacts. There are two challenges in developing BTC: fully densifying the sintered body together with achieving a high toughness. Thus, this review applies towards comprehensively summarize the current knowledge of sintering behavior, microstructure, and mechanical properties of BTC, highlighting the densification improving strategies as well as toughening methods, so as to provide reference for those who would like to enhance the performance of BTC with better reliability advancing them to further wide applications and prepare the material in a way that is environment friendly, harmless to human health and low in production cost. This paper shows that the fabrication of highly dense and high-performance BTC is economically and technically feasible. The properties of BTC can be tailored by judiciously selecting the chemical composition coupled with taking into careful account the effects of processing techniques and parameters.

Robustness versus Performance Assessment for Different Gamma-TiAl Processing Routes

2011 ◽  
Vol 1295 ◽  
Author(s):  
Marc Thomas
Keyword(s):  
High Performance ◽  
Cost Effective ◽  
Processing Route ◽  
Transportation Industry ◽  
Tial Alloys ◽  
Alternative Processing ◽  
Aerospace Applications ◽  
Robust Processing ◽  
Processing Techniques ◽  
Robust Process

ABSTRACTOne of the main driving force for the development of advanced structural materials is weight saving especially in the transportation industry in order to reduce CO2 emission. The utilization of gamma aluminides, as good candidates for aerospace applications, is strongly related to the development of a cost-effective and robust processing route, as far as possible. It is well established that the processing route, i.e. cast, wrought or PM, has a dramatic effect on the microstructure and texture of gamma-TiAl alloys. Therefore, significant microstructural variations through post-heat treatments coupled with compositional modifications can only guarantee a proper balance of desired properties. However, a number of metallurgical factors during the processing steps can contribute to some scattering in properties. This review will highlight several critical process variables in terms of the resulting g-TiAl microstructures. Of primary importance is the as-cast texture which is difficult to control and may contribute to prefer some alternative processing routes to ensure a better repeatability in mechanical results. Some innovative processing techniques for controlling the structure will then be presented. The main point which will be discussed in this paper is whether an approach leading to a robust process would not be at the expense of the high performance of the structural material.

Novel porous tungsten carbide hybrid nanowires on carbon cloth for high-performance hydrogen evolution

2017 ◽  
Vol 5 (25) ◽  
pp. 13196-13203 ◽  
Author(s):  
Bowen Ren ◽  
Dongqi Li ◽  
Qiuyan Jin ◽  
Hao Cui ◽  
Chengxin Wang
Keyword(s):  
Tungsten Carbide ◽  
High Activity ◽  
Hydrogen Evolution ◽  
High Performance ◽  
Alkaline Solutions ◽  
Carbon Cloth ◽  
Porous Tungsten ◽  
Binder Free

Novel 3D porous tungsten carbide hybrid nanowires (p-WCx NWs) are prepared on carbon cloth as a binder-free efficient electrocatalyst for hydrogen evolution. It shows a high activity and outstanding stability in both acidic and alkaline solutions.

Do adaptable employees always display high performance? Dual roles of proactive behavior and self-construal

2021 ◽  
Vol 49 (8) ◽  
pp. 1-16
Author(s):  
Yanzhao Bi ◽  
Jie Zhang ◽  
Qi Nie ◽  
Miaomiao Wang
Keyword(s):  
Organizational Behavior ◽  
Organizational Performance ◽  
High Performance ◽  
Path Model ◽  
Practical Significance ◽  
Career Adaptability ◽  
Proactive Behavior ◽  
Self Construal ◽  
Negative Effect ◽  
Time Lagged

We examined a dual-path model to explain the opposite roles of career adaptability and organizational performance. We used a time-lagged survey of 53 supervisors and 327 employees in China to collect data. Results show that career-oriented proactive behavior mediated the negative effect of career adaptability on performance, and work unitoriented proactive behavior mediated the positive effect of career adaptability on performance. Moreover, the effects of career adaptability and career-oriented proactive behavior on performance were significant only for employees with high independent selfconstrual, and the effects of career adaptability and work unit-oriented proactive behavior on performance were significant only for employees with high interdependent self-construal. This study extends career construction theory in the organizational behavior field and has practical significance for the effective guiding of adaptable employees' contribution to organizational performance.

scholarly journals High-Performance Computing of BEAST/BEAGLE in Bayesian Phylogenetics using SDumont Hybrid Resources

2020 ◽  
Author(s):  
Kary Ocaña ◽  
Micaella Coelho ◽  
Guilherme Freire ◽  
Carla Osthoff
Keyword(s):  
High Performance Computing ◽  
High Performance ◽  
Current Knowledge ◽  
Data Sets ◽  
Length Estimation ◽  
Computationally Intensive ◽  
Mcmc Chain ◽  
Performance Computing ◽  
Insight Into

Bayesian phylogenetic algorithms are computationally intensive. BEAST 1.10 inferences made use of the BEAGLE 3 high-performance library for efficient likelihood computations. The strategy allows phylogenetic inference and dating in current knowledge for SARS-CoV-2 transmission. Follow-up simulations on hybrid resources of Santos Dumont supercomputer using four phylogenomic data sets, we characterize the scaling performance behavior of BEAST 1.10. Our results provide insight into the species tree and MCMC chain length estimation, identifying preferable requirements to improve the use of high-performance computing resources. Ongoing steps involve analyzes of SARS-CoV-2 using BEAST 1.8 in multi-GPUs.

scholarly journals Design and Simulation DFIM Driven Electrical Vehicles Based on IP Controller

2018 ◽  
Vol 17 (2) ◽  
pp. 43-50
Author(s):  
Al-Mayhedee Zubair ◽  
Mohammad Abdul Mannan ◽  
Junji Tamura
Keyword(s):  
High Performance ◽  
Speed Control ◽  
Pi Controller ◽  
Human Beings ◽  
Environment Friendly ◽  
Fundamental Goal ◽  
Electrical Vehicles ◽  
Electrical Vehicle ◽  
High Performance Application ◽  
Control Application

The environment friendly blessings of Electrical Vehicles (EV), human beings are becoming extra involved in the use of them alternatively than the usage of mechanical differentials. In electrical vehicles distinct sorts of electrical machines are used among them DFIM is used in this work. The challenging work is to design of a controller as the output of the motor has to match with vehicle input. So, far, most of the mentioned works have utilized Proportional-Integral (PI) controllers as the speed control. But, the negative aspects of PI controller are properly known, as its design depends on the specific motor parameters and the overall performance is sensitive to system disturbances. The fundamental goal of this paper is to replace the conventional PI controller by means of an IP controller which is successful of dealing with exceedingly non-linear DFIM motor for high performance application in Electrical Vehicle. The effectiveness of designed IP controller of an electrical differential for an EV system is evaluated through Matlab/Simulink software. In simulation work different road conditions for EV are considered. After the simulation the designed controller is found to be strong for the speed control application of Electrical Vehicle.

scholarly journals Severe and regionally-widespread increases in tissue urea in the human brain represent a novel finding of pathogenic potential in Parkinson’s disease dementia

2021 ◽  
Author(s):  
Melissa Scholefield ◽  
Stephanie J. Church ◽  
Jingshu Xu ◽  
Stefano Patassini ◽  
Federico Roncaroli ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
High Performance ◽  
Current Knowledge ◽  
Neuronal Loss ◽  
Middle Temporal Gyrus ◽  
Parkinson’S Disease Dementia ◽  
Pathogenic Potential ◽  
Age Related ◽  
Liquid Chromatography Tandem Mass

Abstract Background: Widespread elevations in brain urea have, in recent years, been reported in certain types of age-related dementia, notably Alzheimer’s disease (AD) and Huntington’s disease (HD). Urea increases in these diseases are substantive, and approximate in magnitude to levels present in uraemic encephalopathy. In AD and HD, elevated urea levels occur across the entire brain, and not only in regions heavily affected by neurodegeneration. However, measurements of brain urea have not hitherto been reported in Parkinson’s disease dementia (PDD), a condition defined by changes in thinking and behaviour in someone with a diagnosis of Parkinson's disease, which shares neuropathological and symptomatic overlap with both AD and HD. This study aims to address this gap in the current knowledge of PDD.Methods: Here we report measurements of tissue urea from nine neuropathologically-confirmed regions of the brain in PDD and post-mortem-delay-matched controls, in regions that included the cerebellum, motor cortex, sensory cortex, hippocampus, substantia nigra, middle temporal gyrus, medulla oblongata, cingulate gyrus, and pons, by applying ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Case-control differences were determined using multiple t-tests followed by correction with 10% false discovery rate.Results: We found urea concentrations to be substantively elevated in all nine regions, the average increase being 3-4-fold. Urea concentrations were remarkably consistent across regions in both cases and controls, with no clear distinction between regions heavily affected by neuronal loss in PDD compared to less severely affected areas. These urea elevations mirror those found in uraemic encephalopathy, where equivalent levels are generally considered to be pathogenic. These urea elevations also reflect those previously reported in AD and HD. Conclusions: Increased urea is a widespread metabolic perturbation in brain metabolism common to PDD, AD, and HD, at levels equal to those seen in uremic encephalopathy. This presents a novel pathogenic mechanism in PDD, which is shared with two other neurodegenerative diseases.

scholarly journals Current knowledge in hypertension genetics: mosaic theory, candidate genes and genome-wide association studies

2020 ◽  
Vol 26 (5) ◽  
pp. 490-500
Author(s):  
A. O. Konradi
Keyword(s):  
Candidate Genes ◽  
High Performance ◽  
New Technologies ◽  
Current Knowledge ◽  
Association Studies ◽  
Genome Wide Association ◽  
Genome Wide Association Studies ◽  
Modern Approach ◽  
Genome Wide

The article reviews monogenic forms of hypertension, data on the role of heredity of essential hypertension and candidate genes, as well as genome-wide association studies. Modern approach for the role of genetics is driven by implementation of new technologies and their productivity. High performance speed of new technologies like genome-wide association studies provide data for better knowledge of genetic markers of hypertension. The major goal nowadays for research is to reveal molecular pathways of blood pressure regulation, which can help to move from populational to individual level of understanding of pathogenesis and treatment targets.

scholarly journals CURRENT STATE OF APPLIENCE ZIRCONIUM DIOXIDE IN BIOENGINEERING

2020 ◽  
Vol 4 ◽  
pp. 39-42
Author(s):  
Oksana Morozova ◽  
Edwin Gevorkyan
Keyword(s):  
Fracture Toughness ◽  
Composite Materials ◽  
Zirconium Dioxide ◽  
High Performance ◽  
Current Knowledge ◽  
High Hardness ◽  
Color Stability ◽  
Orthopedic Implants ◽  
Advantages And Disadvantages ◽  
Alternative Material

This descriptive review presents current knowledge about the bioengineering use of a zirconium dioxide, the advantages and disadvantages of the material, and the prospects for research in this direction. The work reflects the success of the practical application of the zirconium dioxide as a material for dental structures and biological implants. Such practical characteristics, such as color-stability, chemical stability, good aesthetics, biocompatibility and durability, allowed to actively use the zirconium dioxide as a material for producing various dental structures. In comparison with other ceramics, the presence of high-performance of strength and fracture toughness of the zirconium dioxide enables the use of this material as an alternative material for the reconstructions in the readings with considerable loads. High hardness determines the zirconium dioxide as an excellent material for articular prostheses, because of its hardness, provides a low level of wear and excellent biocompatibility. However, along with positive characteristics, a widespread practical problem of using the zirconium dioxide in dentistry is a chip or fracture of veneering ceramics. It has also been reported that there is a shortage of orthopedic implants such as hydrothermal stability. The solution of such problems is indicated and the use of composite materials based on the zirconium dioxide, which allows to solve a similar problem, as well as to increase the service life and reliability of orthopedic implants by providing a higher fracture toughness and mechanical strength. The existence of such composite materials based on the zirconium dioxide provides a significant increase in the wear resistance of orthopedic implants, which is essential for successful prosthetics

Metallography and Biomimetics – Or New Surfaces Without Chemistry?

2021 ◽  
Vol 58 (7) ◽  
pp. 446-459
Author(s):  
T. Fox ◽  
S. M. Lößlein ◽  
D. W. Müller ◽  
F. Mücklich
Keyword(s):  
Economic Cost ◽  
Electrical Contacts ◽  
Structured Surfaces ◽  
Multi Scale ◽  
Direct Laser ◽  
One Step ◽  
Fine Structures ◽  
Scale Structures ◽  
Processing Techniques ◽  
Direct Laser Interference Patterning

Abstract Fingerprints, a butterfly’s wings, or a lotus leaf: when it comes to surfaces, there is no such thing as coincidence in animated nature. Based on their surfaces, animals and plants control their wettability, their swimming resistance, their appearance, and much more. Evolution has optimized these surfaces and developed a microstructure that fits every need. It is all the more astonishing that, with regard to technical surfaces, man confines himself to random roughnesses or “smooth” surfaces. It is surely not a problem of a lack of incentives: structured surfaces have already provided evidence of optimizing friction and wear [1, 2, 3, 4], improving electrical contacts [5, 6], making implants biocompatible [7, 8], keeping away harmful bacteria [9], and much more. How come we continue counting on grinding, polishing, sandblasting, or etching? As so often, the problem can be found in economic cost effectiveness. It is possible to produce interesting structures such as those of the feather in Fig. 1. However, generating fine structures in the micro and nanometer range usually requires precise processing techniques. This is complex, time-consuming, and cannot readily be integrated into a manufacturing process. Things are different with Direct Laser Interference Patterning, DLIP) [10, 11]. This method makes use of the strong interference pattern of overlapped laser beams as a “stamp” to provide an entire surface area with dots, lines, or other patterns – in one shot. It thus saves time, allows for patterning speeds of up to 1 m2/min and does it without an elaborate pre- or post-treatment [10, 12]. The following article intends to outline how the method works, which structures can be generated, and how the complex multi-scale structures that nature developed over millions of years can be replicated in only one step.

CRISPR/Cas9-induced β-carotene Hydroxylase Mutation in Dunaliella Salina CCAP19/18

2021 ◽  
Author(s):  
Lina Hu ◽  
Shu ying FENG ◽  
Gaofeng Liang ◽  
Jingxia Du ◽  
Aifang Li ◽  
...  
Keyword(s):  
High Performance ◽  
Dunaliella Salina ◽  
Gene Editing ◽  
Expression System ◽  
Transformation Method ◽  
Practical Significance ◽  
Exon 1 ◽  
Targeted Gene Editing ◽  
Foreign Genes ◽  
Β Carotene

Abstract Dunaliella salina (D. salina) has been exploited as a novel expression system for the field of genetic engineering. However, owing to the low or inconsistent expression of target proteins, it has been greatly restricted to practical production of recombinant proteins. Since the accurate gene editing function of CRISPR/Cas system, β-carotene hydroxylase gene was chosen as an example to explore D. salina application with the purpose of improving expression level of foreign genes. In this paper, based on pKSE401 backbone, three CRISPR/Cas9 binary vectors were constructed to targeting exon 1 and 3 of the β-carotene hydroxylase of D. salina CCAP19/18 (Dschyb). D. salina mutants were obtained by salt gradient transformation method, and the expression of Dschyb gene were identified through real-time fluorescent quantitative PCR. Moreover, carotenoids content was analyzed by high-performance liquid chromatography at different time points after high intensity treatment. Compared with wild type strains, the β-carotene levels of mutants showed a significant increase, nearly up to 1.4 μg/ml, and the levels of zeaxanthin decreased to various degrees in mutants. All the results provide a compelling evidence for targeted gene editing in D. salina. This study gave a first successful gene editing of D. salina which has a very important practical significance for increasing carotene yield and meeting realistic industry demand. Furthermore, it provides an approach to overcome the current obstacles of D. salina, and then gives a strong tool to facilitates the development and application of D. salina system.

Sign in / Sign up

Export Citation Format

Share Document