scholarly journals Experimental Investigation of the Triple-Junction Effect on the Electric Discharge Characteristics and Modeling of the Maximum Discharge Current

Author(s):  
Nabila Saim ◽  
Ferroudja Bitam-Megherbi

The electrical discharge and breakdown characteristics of a triple junction (TJ) in high voltage (HV) electrical insulation are becoming an important issue in recent industrial applications. In this paper, a comparative study is conducted between three insulation materials used in HV: silicone, porcelain, and heat tempered glass, with electrode shape parameters such as inter-electrode distance (d), applied voltage (V), and geometry investigated for positive polarity, using an experimental approach. For optimum test organization to support our research and highlight the parameters and their interactions, we have established a mathematical regression model of the discharge current. It is polynomial, with good performance and a high level of precision. Besides, this yields one monovariable and another two-variable quadratic model. The latter can simulate the electric discharge simultaneously with two variables: V and d, and an adjusted determination coefficient () of nearly 0.99. Consequently, the two-variable quadratic model has been adapted to V and d ranges of 10 to 50 kV and 1.9 to 8 cm, respectively. Finally, this study provides us with new applicable knowledge about the TJ effect on electrical insulation with recommendations to optimize the design for higher performance.

2020 ◽  
Vol 09 ◽  
Author(s):  
Ahmed M. Abu-Dief ◽  
W. S. Mohamed

Abstract:: Sustainability environmental lack is a growing and pivotal mater due to the issues: such as disturbances associated with biodiversity pollution, and climate change. Pollutants are the major cause of these environmental threats in the atmosphere. In recently, the nano-based photocatalyst is at the forefront of the author's interest because of its promising potential as a green chemical-based compound, high catalytic activity, the suitable and controllable surface area for wastewater treatment. Semiconductor materials in nanosized scale have electronic and optical properties depend on its building block size, which plays a vital role in developing smart materials that are well efficient for simultaneously destroying harmful chemical contaminants from our environment. This makes these materials used in many possible industrial applications such as water purification. In this Review, we report the most significant results contributing to progress in the area of environmental hazardous pollutant detection and removal focused on water purification especially through photo-catalysis to give readers an overview of the present research trends. Moreover, we analyze previous studies to indicate key principles of photo-catalysis and provide guidelines that can be used to fabricate more efficient photocatalysts.


2021 ◽  
Vol 11 (9) ◽  
pp. 3921
Author(s):  
Paloma Carrasco ◽  
Francisco Cuesta ◽  
Rafael Caballero ◽  
Francisco J. Perez-Grau ◽  
Antidio Viguria

The use of unmanned aerial robots has increased exponentially in recent years, and the relevance of industrial applications in environments with degraded satellite signals is rising. This article presents a solution for the 3D localization of aerial robots in such environments. In order to truly use these versatile platforms for added-value cases in these scenarios, a high level of reliability is required. Hence, the proposed solution is based on a probabilistic approach that makes use of a 3D laser scanner, radio sensors, a previously built map of the environment and input odometry, to obtain pose estimations that are computed onboard the aerial platform. Experimental results show the feasibility of the approach in terms of accuracy, robustness and computational efficiency.


2020 ◽  
Vol 1008 ◽  
pp. 33-38
Author(s):  
Marwa Nabil ◽  
Hussien A. Motaweh

Silica is one of the most important materials used in many industries. The basic factor on which the selection process depends is the structural form, which is dependent on the various physical and chemical properties. One of the common methods in preparing pure silica is that it needs more than one stage to ensure the preparation process completion. The goal of this research is studying the nucleation technique (Bottom-top) for micro-wires and micro-ribbons silica synthesis. The silica nanoand microstructures are prepared using a duality (one step); a combination of alkali chemical etching process {potassium hydroxide (3 wt %) and n-propanol (30 Vol %)} and the ultra-sonication technique. In addition, the used materials in the preparation process are environmentally friendly materials that produce no harmful residues. The powder product is characterized using XRD, FTIR, Raman spectrum and SEM for determining the shape of architectures. The most significant factor of the nucleation mechanism is the sonication time of silica powder production during the dual technique. The product stages are as follows; silica nanoparticles (21-38 nm), nanoclusters silica (46 – 67 nm), micro-wires silica (1.17 – 6.29 μm), and micro-ribbons silica (19.4 – 54.1 μm). It's allowing for use in environmental applications (multiple wastewater purification, multiple uses in air filters, as well as many industrial applications).


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mohamed A. Farag ◽  
Moamen M. Elmassry ◽  
Masahiro Baba ◽  
Renée Friedman

Abstract Previous studies have shown that the Ancient Egyptians used malted wheat and barley as the main ingredients in beer brewing, but the chemical determination of the exact recipe is still lacking. To investigate the constituents of ancient beer, we conducted a detailed IR and GC-MS based metabolite analyses targeting volatile and non-volatile metabolites on the residues recovered from the interior of vats in what is currently the world’s oldest (c. 3600 BCE) installation for large-scale beer production located at the major pre-pharaonic political center at Hierakonpolis, Egypt. In addition to distinguishing the chemical signatures of various flavoring agents, such as dates, a significant result of our analysis is the finding, for the first time, of phosphoric acid in high level probably used as a preservative much like in modern beverages. This suggests that the early brewers had acquired the knowledge needed to efficiently produce and preserve large quantities of beer. This study provides the most detailed chemical profile of an ancient beer using modern spectrometric techniques and providing evidence for the likely starting materials used in beer brewing.


2016 ◽  
Vol 256 ◽  
pp. 319-327 ◽  
Author(s):  
Mario Rosso ◽  
Ildiko Peter ◽  
Ivano Gattelli

During the last decades under the enthusiastic and competent guidance of Mr Chiarmetta SSM processes attained in Italy at Stampal Spa (Torino) an unquestionable high level of industrial development with the production of large numbers of high performance automotive parts, like variety of suspension support, engine suspension mounts, steering knuckle, front suspension wheel, arm and rear axle. Among the most highlighted findings SSM processes demonstrated their capability to reduce the existing gap between casting and forging, moreover during such a processes there are the opportunity to better control the defect level.Purpose of this paper is to highlight the research work and the SSM industrial production attained and developed by Mr G.L. Chiarmetta, as well as to give an overview concerning some alternative methods for the production of enhanced performance light alloys components for critical industrial applications and to present an analysis of a new rheocasting process suitable for the manufacturing of high performance industrial components.


2015 ◽  
Vol 137 (08) ◽  
pp. 42-45
Author(s):  
Mike Vasquez

This article reviews the challenges for companies while adopting three-dimensional (3D) printing technology. A big challenge for companies figuring out whether they need to invest in 3-D printing is the different types of printing systems available in the market. At a high level, there are seven different families of 3-D printing processes. Each of the seven technologies is differentiated by the materials used and how the materials are fused together to create three-dimensional objects. Another barrier is that most companies have not yet found it viable to put the processes in place to incorporate the change in design, engineering, and manufacturing production that is required. Not only capital funds are needed to purchase machines, but to effectively use the technology to create a sellable product, one also needs to have a targeted product line and clear vision of the ways that 3-D printing can help lower material costs, save energy, and simplify manufacturing and assembly.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8297 ◽  
Author(s):  
Asep A. Prihanto ◽  
Rahmi Nurdiani ◽  
Annas D. Bagus

Background Fish byproducts are commonly recognized as low-value resources. In order to increase the value, fish byproducts need to be converted into new products with high functionality such as fish protein hydrolysate (FPH). In this study, FPH manufactured from parrotfish (Chlorurus sordidus) heads using different pH, time and sample ratio was investigated. Methods Hydrolysis reactions were conducted under different pHs (5, 7, and 9) and over different durations (12 and 24 h). Control treatment (without pH adjustment (pH 6.4)) and 0 h hydrolsisis duration were applied. Hydrolysates were characterized with respect to proximate composition, amino acid profile, and molecular weight distribution. The antioxidant activity of the hydrolysate was also observed. Results The pH and duration of hydrolysis significantly affected (p < 0.05) the characteristics of FPH. The highest yield of hydrolysate (49.04 ± 0.90%), with a degree of hydrolysis of 30.65 ± 1.82%, was obtained at pH 9 after 24 h incubation. In addition, the FPH had high antioxidant activity (58.20 ± 0.55%), with a high level of essential amino acids. Results suggested that FPH produced using endogenous enzymes represents a promising additive for food and industrial applications.


2017 ◽  
Author(s):  
Federica Rosetta

Watch the VIDEO here.Within the Open Science discussions, the current call for “reproducibility” comes from the raising awareness that results as presented in research papers are not as easily reproducible as expected, or even contradicted those original results in some reproduction efforts. In this context, transparency and openness are seen as key components to facilitate good scientific practices, as well as scientific discovery. As a result, many funding agencies now require the deposit of research data sets, institutions improve the training on the application of statistical methods, and journals begin to mandate a high level of detail on the methods and materials used. How can researchers be supported and encouraged to provide that level of transparency? An important component is the underlying research data, which is currently often only partly available within the article. At Elsevier we have therefore been working on journal data guidelines which clearly explain to researchers when and how they are expected to make their research data available. Simultaneously, we have also developed the corresponding infrastructure to make it as easy as possible for researchers to share their data in a way that is appropriate in their field. To ensure researchers get credit for the work they do on managing and sharing data, all our journals support data citation in line with the FORCE11 data citation principles – a key step in the direction of ensuring that we address the lack of credits and incentives which emerged from the Open Data analysis (Open Data - the Researcher Perspective https://www.elsevier.com/about/open-science/research-data/open-data-report ) recently carried out by Elsevier together with CWTS. Finally, the presentation will also touch upon a number of initiatives to ensure the reproducibility of software, protocols and methods. With STAR methods, for instance, methods are submitted in a Structured, Transparent, Accessible Reporting format; this approach promotes rigor and robustness, and makes reporting easier for the author and replication easier for the reader.


Author(s):  
Rusen Zhou ◽  
Baowang Liu ◽  
Yiyang Li ◽  
Renwu Zhou ◽  
Wenshao Li ◽  
...  

Abstract Minimizing the breakdown voltage and discharge current required to initiate direct in-liquid discharges, thus lowering power-source requirements and avoiding electrode ablation, is crucial for industrial applications of in-liquid plasma discharges. Here we demonstrate such considerable reductions by employing movable electrodes, without changing the electrode configuration or increasing the system complexity. The new mechanism is based on electrostatic electrode attraction resulting in a reduction in the discharge spacing by up to 6 times and facilitating a plasma initiation at lower breakdown voltages. The accumulated charges consumed by the discharge revert the electrodes to the initial positions, forming a gliding arc between the enlarged gaps and thus inhibiting current increases and electrode ablation.


2021 ◽  
Vol 35 (04) ◽  
pp. 2150057
Author(s):  
Qunfeng Zeng ◽  
Khashayar Khanlari ◽  
Naiming Lin

Equiatomic and near equiatomic NiTi alloys, showing good mechanical and thermal shape memory properties, are widely exploited in different industrial applications. In addition, NiTi alloys have promising anti-cavitation and corrosion-resistance properties. These advantages have provided opportunities to exploit NiTi alloys as the coatings for protecting materials used in the industrial applications. This study is a preliminary investigation aiming to evaluate the feasibility to form NiTi alloy coatings on SS304 steel by tungsten inert argon arc welding (TIG) technology. The microstructure analysis shows that the crystalline phases in NiTi coatings on SS 304 steel are TiNi-B2, TiNi-B19’ and Ni3Ti. The potential of the NiTi coatings to enhance the corrosion resistance and cavitation resistance behaviors of steel exposed to seawater is studied. NiTi coatings, with two different thicknesses of about 1.2 and 2 mm, having homogenous microstructures were successfully deposited on SS304 steel using TIG technology. Results of tests, done in aqueous solutions simulating seawater, showed that the formation of the oxide films on the surface of NiTi coatings increased the corrosion resistance and wear resistance and decreased the damage caused by the cavitation. Moreover, it was understood that the NiTi coatings with 2 mm in thickness show the superior performances than those with 1.2 mm in thickness. The tribological mechanisms responsible for the unique properties of NiTi alloy coatings were investigated. The wear-resistance behaviors of NiTi alloy coatings are greatly influenced by the friction conditions. Increasing load decreased CoF and the wear rate of the coatings were almost constant, which was attributed to the pseudoelasticity of NiTi alloy. The attractive properties of NiTi alloys that makes it most influential materials for industrial applications have also been discussed.


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