Análise de revestimento dielétrico de um sensor UHF de microfita aplicado na detecção de descargas parciais em transformadores de potência

<p class="Normal1">The use of UHF sensors in high voltage electrical equipment for monitoring its insulation system is widely used. In order to improve these sensors,we present an analysis of different types of dielectric materials that can be used as physical coating and shield, which can enhance the electromagnetic characteristics of UHF microstrip sensors applied to the detection of partial discharges in performance transformers. The materials used as coating were glass, silicone, FR4, Teflon, and acrylic. In order to do so,, HFSS software simulations for the development of analyzes on two UHF microstrip antennas were performed. From the analyzes performed, it was verified the improvement of the reflection coefficient and the gain of the UHF sensor recorded the materials used to demonstrate the practical application. In addition to that, we also had simulations of a typical electromagnetic shield applied in conjunction with the sensor to demonstrate that the shield is still displayed in the design stages and is of great relevance. In order to underpin the data obtained from the simulations, the real models of UHF sensors were applied and tested in the laboratory.</p>

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Breathable Materials for Triboelectric Effect-Based Wearable Electronics

Applied Sciences ◽

10.3390/app8122485 ◽

2018 ◽

Vol 8 (12) ◽

pp. 2485 ◽

Cited By ~ 5

Author(s):

Congju Li ◽

Ran Cao ◽

Xiuling Zhang

Keyword(s):

Recent Progress ◽

Dielectric Materials ◽

Wearable Devices ◽

Wearable Electronics ◽

Practical Application ◽

Metal Mesh ◽

Frictional Materials ◽

Nanofiber Membranes ◽

Materials Used ◽

Triboelectric Effect

Wearable electronics are believed to be the future of the next-generation electric devices. However, the comfort of current wearable devices is greatly limited due to the use of airtight materials, which may even lead to inflammation of the skin. Therefore, breathable, skin-friendly materials, are highly desired for wearable devices. Here, the recent progress of the breathable materials used to fabricate skin-friendly electronics is reviewed by taking triboelectric effect-based wearable electronics as a typical example. Fibers, yarns, textiles, and nanofiber membranes are the most popular dielectric materials that serve as frictional materials. Metal mesh, silver yarn, and conductive networks made up of nanomaterial are preferred as air-permissive electrodes. The breathable materials for skin-friendly wearable electronics summarized in this review provide valuable references for future fabrication of humanized wearable devices and hold great significance for the practical application of wearable devices.

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Surface flashover of dielectric materials used in pulsed power research

2007 IEEE Pulsed Power Plasma Science Conference ◽

10.1109/ppps.2007.4652510 ◽

2007 ◽

Cited By ~ 1

Author(s):

M.P. Wilson ◽

R.A. Fouracre ◽

M.J. Given ◽

S.J. MacGregor ◽

I.V. Timoshkin ◽

...

Keyword(s):

Dielectric Materials ◽

Pulsed Power ◽

Surface Flashover ◽

Materials Used

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Advances in Forest Robotics: A State-of-the-Art Survey

Robotics ◽

10.3390/robotics10020053 ◽

2021 ◽

Vol 10 (2) ◽

pp. 53

Author(s):

Luiz F. P. Oliveira ◽

António P. Moreira ◽

Manuel F. Silva

Keyword(s):

Future Research ◽

Navigation Systems ◽

Public And Private ◽

Environmental Preservation ◽

The Public ◽

Forest Exploitation ◽

Different Types ◽

Scientific Papers ◽

Great Relevance ◽

Robotic Applications

The development of robotic systems to operate in forest environments is of great relevance for the public and private sectors. In this sense, this article reviews several scientific papers, research projects and commercial products related to robotic applications for environmental preservation, monitoring, wildfire firefighting, inventory operations, planting, pruning and harvesting. After conducting critical analysis, the main characteristics observed were: (a) the locomotion system is directly affected by the type of environmental monitoring to be performed; (b) different reasons for pruning result in different locomotion and cutting systems; (c) each type of forest, in each season and each type of soil can directly interfere with the navigation technique used; and (d) the integration of the concept of swarm of robots with robots of different types of locomotion systems (land, air or sea) can compensate for the time of executing tasks in unstructured environments. Two major areas are proposed for future research works: Internet of Things (IoT)-based smart forest and navigation systems. It is expected that, with the various characteristics exposed in this paper, the current robotic forest systems will be improved, so that forest exploitation becomes more efficient and sustainable.

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Biopolymeric Materials Used as Nonviral Vectors: A Review

Polysaccharides ◽

10.3390/polysaccharides2010007 ◽

2021 ◽

Vol 2 (1) ◽

pp. 100-109

Author(s):

Jailson de Araújo Santos ◽

Daniel Barbosa Liarte ◽

Alessandra Braga Ribeiro ◽

Marcia dos Santos Rizzo ◽

Marcília Pinheiro da Costa ◽

...

Keyword(s):

Chemical Structure ◽

Web Of Science ◽

Gene Transfection ◽

Genetic Material ◽

Nonviral Vectors ◽

Cationic Polymers ◽

Genetic Trait ◽

Low Diversity ◽

Different Types ◽

Materials Used

Bacterial transformation and gene transfection can be understood as being the results of introducing specific genetic material into cells, resulting in gene expression, and adding a new genetic trait to the host cell. Many studies have been carried out to investigate different types of lipids and cationic polymers as promising nonviral vectors for DNA transfer. The present study aimed to carry out a systematic review on the use of biopolymeric materials as nonviral vectors. The methodology was carried out based on searches of scientific articles and applications for patents published or deposited from 2006 to 2020 in different databases for patents (EPO, USPTO, and INPI) and articles (Scopus, Web of Science, and Scielo). The results showed that there are some deposits of patents regarding the use of chitosan as a gene carrier. The 16 analyzed articles allowed us to infer that the use of biopolymers as nonviral vectors is limited due to the low diversity of biopolymers used for these purposes. It was also observed that the use of different materials as nonviral vectors is based on chemical structure modifications of the material, mainly by the addition of cationic groups. Thus, the use of biopolymers as nonviral vectors is still limited to only a few polysaccharide types, emphasizing the need for further studies involving the use of different biopolymers in processes of gene transfer.

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Regulating for Content on the Internet: Meeting Cultural and Social Objectives for Broadband

Media International Australia ◽

10.1177/1329878x0110100105 ◽

2001 ◽

Vol 101 (1) ◽

pp. 19-31 ◽

Cited By ~ 3

Author(s):

Gerard Goggin ◽

Catherine Griff

Keyword(s):

The Internet ◽

Final Report ◽

Media Convergence ◽

Different Types ◽

The Future ◽

Broadcasting Regulation ◽

Productivity Commission ◽

Specific Regulation ◽

Film And Video ◽

Do So

Much of the present debate about content on the internet revolves around how to control the distribution of different sorts of harmful or undesirable material. Yet there are considerable issues about whether sufficient sorts of desired cultural content will be available, such as ‘national’, ‘Australian’ content. In traditional broadcasting, regulation has been devised to encourage or mandate different types of content, where it is believed that the market will not do so by itself. At present, such regulatory arrangements are under threat in television, as the Productivity Commission Broadcasting Inquiry final report has noted. But what of the future for certain types of content on the internet? Do we need specific regulation and policy to promote the availability of content on the internet? Or is such a project simply irrelevant in the context of gradual but inexorable media convergence? Is regulating for content just as quixotic and fraught with peril as regulating of content from a censorship perspective often appears to be? In this article, we consider the case of Australian content for broadband technologies, especially in relation to film and video, and make some preliminary observations on the promotion and regulation of internet content.

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Accessing offshoring advantages: what and how to offshore

Strategic Outsourcing An International Journal ◽

10.1108/so-07-2015-0017 ◽

2015 ◽

Vol 8 (2/3) ◽

pp. 262-283 ◽

Cited By ~ 11

Author(s):

Alona Mykhaylenko ◽

Ágnes Motika ◽

Brian Vejrum Waehrens ◽

Dmitrij Slepniov

Keyword(s):

Performance Outcomes ◽

Offshore Outsourcing ◽

Strategic Decisions ◽

Content Type ◽

Different Types ◽

Captive Offshoring ◽

Performance Results ◽

Governance Modes ◽

Different Levels ◽

Do So

Purpose – The purpose of this paper is to advance the understanding of factors that affect offshoring performance results. To do so, this paper focuses on the access to location-specific advantages, rather than solely on the properties of the offshoring company, its strategy or environment. Assuming that different levels of synergy may exist between particular offshoring strategic decisions (choosing offshore outsourcing or captive offshoring and the type of function) and different offshoring advantages, this work advocates that the actual fact of realization of certain offshoring advantages (getting or not getting access to them) is a more reliable predictor of offshoring success. Design/methodology/approach – A set of hypotheses derived from the extant literature is tested on the data from a quantitative survey of 1,143 Scandinavian firms. Findings – The paper demonstrates that different governance modes and types of offshored function indeed provide different levels of access to different types of location-specific offshoring advantages. This difference may help to explain the ambiguity of offshoring initiatives performance results. Research limitations/implications – Limitations of the work include using only the offshoring strategy elements and only their limited variety as factors potentially influencing access to offshoring advantages. Also, the findings are limited to Scandinavian companies. Originality/value – The paper introduces a new concept of access, which can help to more reliably predict performance outcomes of offshoring initiatives. Recommendations are also provided to practitioners dealing with offshoring initiatives.

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Mechanical Properties of Graphene Oxide–Copper Composites

Archives of Metallurgy and Materials ◽

10.1515/amm-2016-0146 ◽

2016 ◽

Vol 61 (2) ◽

pp. 863-868 ◽

Cited By ~ 3

Author(s):

P. Duda ◽

R. Muzyka ◽

Z. Robak ◽

S. Kaptacz

Keyword(s):

Graphene Oxide ◽

Tribological Properties ◽

Low Voltage ◽

Electrical Equipment ◽

Oxide Content ◽

Large Current ◽

Current Densities ◽

Materials Used ◽

System Disk ◽

Positive Effect

Abstract Due to their characteristics, sintered Cu-C composites are materials used in electrical equipment. These characteristics include high electrical conductivity, thermal conductivity and excellent resistance to abrasion. Currently, graphite nanopowder is used successfully as a carbon material. Metal-graphite, which is created on its basis, exists in different proportions of graphite to metal. A larger graphite content has a positive effect on smaller wear of commutators and rings. In contrast, a material with a higher copper content is used at high current densities. An example of such machines is a DC motor starter characterized by low voltage and large current. Tribological properties of Cu-C composites depend on the form of carbon they include. Owing to the capability to manufacture graphene, it has become possible to produce composites with its content. The present study tested the effect of a graphene oxide content on tribological properties in contact with steel. Tests were conducted on a ball-on-disk apparatus in conditions of dry friction. Microscopic observation was performed on the Hitachi SU70 field emission electron microscope. EDS analyses were performed using the Thermo Scientific X-ray Microanalysis system. Disk wear and surface geometrical structure parameters (SGP) of the samples after tribological tests were determined on the basis of measurements made on the Talysurf 3D contact profilometer from Taylor Hobson.

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Practical Application of a Data Stewardship Maturity Matrix for the NOAA OneStop Project

10.31219/osf.io/fp3js ◽

2018 ◽

Author(s):

Ge Peng ◽

Anna Milan ◽

Nancy A. Ritchey ◽

Robert P. Partee ◽

Sonny Zinn ◽

...

Keyword(s):

North Carolina ◽

Best Practices ◽

Data Quality ◽

User Needs ◽

Data Quality Control ◽

Practical Application ◽

Data Discovery ◽

Data Quality Assessment ◽

Data Stewardship ◽

Do So

Assessing the stewardship maturity of individual datasets is an essential part of ensuring and improving the way datasets are documented, preserved, and disseminated to users. It is a critical step towards meeting U.S. federal regulations, organizational requirements, and user needs. However, it is challenging to do so consistently and quantifiably. The Data Stewardship Maturity Matrix (DSMM), developed jointly by NOAA’s National Centers for Environmental Information (NCEI) and the Cooperative Institute for Climate and Satellites–North Carolina (CICS-NC), provides a uniform framework for consistently rating stewardship maturity of individual datasets in nine key components: preservability, accessibility, usability, production sustainability, data quality assurance, data quality control/monitoring, data quality assessment, transparency/traceability, and data integrity. So far, the DSMM has been applied to over 900 individual datasets that are archived and/or managed by NCEI, in support of the NOAA’s OneStop Data Discovery and Access Framework Project. As a part of the OneStop-ready process, tools, implementation guidance, workflows, and best practices are developed to assist the application of the DSMM and described in this paper. The DSMM ratings are also consistently captured in the ISO standard-based dataset-level quality metadata and citable quality descriptive information documents, which serve as interoperable quality information to both machine and human end-users. These DSMM implementation and integration workflows and best practices could be adopted by other data management and stewardship projects or adapted for applications of other maturity assessment models.

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Location Depending Textures of the Human Dental Enamel

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.160.281 ◽

2010 ◽

Vol 160 ◽

pp. 281-286 ◽

Cited By ~ 6

Author(s):

Lars Raue ◽

Helmut Klein

Keyword(s):

Mechanical Properties ◽

Lactic Acid ◽

Dental Enamel ◽

Polymeric Materials ◽

Incisor Tooth ◽

Worst Case ◽

Dental Fillings ◽

Anisotropic Mechanical Properties ◽

Different Types ◽

Materials Used

Dental enamel is the most highly mineralised and hardest biological tissue in human body [1]. Dental enamel is made of hydroxylapatite (HAP) - Ca5(PO4)3(OH), which is hexagonal (6/m). The lattice parameters are a = b = 0.9418 nm und c = 0.6875 nm [1]. Although HAP is a very hard mineral, it can be dissolved easily in a process which is known as enamel demineralization by lactic acid produced by bacteria. Also the direct consumption of acid (e.g. citric, lactic or phosphoric acid in soft drinks) can harm the dental enamel in a similar way. These processes can damage the dental enamel. It will be dissolved completely and a cavity occurs. The cavity must then be cleaned and filled. It exists a lot of dental fillings, like gold, amalgam, ceramics or polymeric materials. After filling other dangers can occur: The mechanical properties of the materials used to fill cavities can differ strongly from the ones of the dental enamel itself. In the worst case, the filling of a tooth can damage the enamel of the opposite tooth by chewing if the interaction of enamel and filling is not equivalent, so that the harder fillings can abrade the softer enamel of the healthy tooth at the opposite side. This could be avoided if the anisotropic mechanical properties of dental enamel would be known in detail, hence then another filling could be searched or fabricated as an equivalent opponent for the dental enamel with equal properties. To find such a material, one has to characterise the properties of dental enamel first in detail for the different types of teeth (incisor, canine, premolar and molar). This is here exemplary done for a human incisor tooth by texture analysis with the program MAUD from 2D synchrotron transmission images [2,3,4].

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LOW LOSS DIELECTRIC MATERIALS FOR HIGH FREQUENCY APPLICATIONS

International Journal of Modern Physics B ◽

10.1142/s0217979209063122 ◽

2009 ◽

Vol 23 (17) ◽

pp. 3649-3654 ◽

Cited By ~ 1

Author(s):

MOHAN V. JACOB

Keyword(s):

High Frequency ◽

Room Temperature ◽

Low Cost ◽

Dielectric Materials ◽

Dielectric Constants ◽

Transmission Losses ◽

Low Loss ◽

Microwave Characterization ◽

Materials Used ◽

Low Temperature Electronics

The microwave properties of some of the low cost materials which can be used in high frequency applications with low transmission losses are investigated in this paper. One of the most accurate microwave characterization techniques, Split Post Dielectric Resonator technique (SPDR) is used for the experimental investigation. The dielectric constants of the 3 materials scrutinized at room temperature and at 10K are 3.65, 2.42, 3.61 and 3.58, 2.48, 3.59 respectively. The corresponding loss tangent values are 0.00370, 0.0015, 0.0042 and 0.0025, 0.0009, 0.0025. The high frequency transmission losses are comparable with many of the conventional materials used in low temperature electronics and hence these materials could be implemented in such applications.

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