Study on stress testing of ferromagnetic materials based on magnetic anisotropy

The stress testing and evaluation of ferromagnetic materials that are widely applied in engineering has always been a focus of, and presented difficulties for, non-destructive testing. As there is still no effective method for detecting the stress of ferromagnetic materials, this paper puts forward the idea of applying the magnetic anisotropy method based on the inverse magnetostriction effect in stress testing of ferromagnetic materials. According to the principle of the magnetic anisotropy method, this paper discusses the development of Mn-Zn ferrite probes of three different structures, the construction of a magnetic anisotropy testing system comprising an excitation system, a signal collecting system and a signal processing system and the way in which a testing experiment was conducted on a 16MnR steel plate specimen under different conditions of stress, frequency and excitation voltage. All three types of probe can effectively determine the stress location of the specimen and present different phenomena and characteristics of the test. According to the experiment, significant correlation is seen between the stress and the magnetic signal, which provides a new idea for stress testing of ferromagnetic materials.

Magnetic field assisted electrocatalytic oxygen evolution reaction of nickel-based materials

The dominant role of the magnetoresistance effect caused by spin electron scattering in the oxygen evolution reaction is unveiled through an in situ tunable magnetic field-electrochemical testing system.

Study of the Influence of Nonlinear Dynamic Loads on Elastic Modulus of Carbonate Reservoir Rocks

The paper presents the results of the experimental investigation of carbonate reservoir rocks subjected to quasistatic and nonlinear dynamic loads. During the quasistatic loading the zones of linear elasticity were determined. Dynamic loading of samples was performed at several frequencies and load amplitudes using a testing system. There were two zones found in which the elastic modulus changes nonlinearly in terms of dynamic load frequency. While the frequency of the dynamic load increases from 0 to 10 Hz the dynamic elastic modulus rises according to logarithmic law; while the frequency increases from 10 to 60 Hz elastic modulus rises according to a power law for each load amplitude. The amplitude of the longitudinal strain and phase shift decreases with increasing frequency of the dynamic load. Under the higher strain rates the rock gets stiffer in comparison with rock subjected to smaller strain rate dynamic loading. Saturation of rock samples with distilled water flattening the dependencies of dynamic Young’s modulus on frequency.

EXAMES DE INVESTIGAÇÃO PRECOCE DO CÂNCER DE COLO UTERINO: UMA REVISÃO LITERÁRIA

Introdução: O câncer de colo uterino está relacionado principalmente as alterações causadas por subtipos oncogênicos do papilomavírus humano (HPV). Os subtipos 16 e 18 estão envolvidos em 70% dos casos. Essa patologia apresenta considerável impacto na população feminina, pois, no Brasil, é o quarto mais incidente em causa de mortalidade e também ocupa a quarta posição em incidência ao nível mundial. Objetivos: analisar meios de investigação precoce do câncer de colo uterino no intuito de prevenir morbidade e mortalidade. Material e Métodos: Foi realizada uma pesquisa bibliográfica de natureza qualitativa e de caráter exploratório na base de dados Pubmed e Scielo utilizando os descritores neoplasias do colo do útero, técnicas e procedimentos diagnósticos. Os critérios de inclusão foram artigos publicados nos últimos cinco anos. Resultados: Os métodos de investigação precoce do câncer de colo uterino encontrados foram papanicolau, HPV testing e careHPV testing system. O método mais utilizado é o teste de rastreamento Papanicolau, analisa possíveis anormalidades celulares na junção escamocolunar do colo uterino, apresentando sensibilidade aproximadamente de 98% e sensibilidade de 55 a 80% na detecção de câncer invasivo e contribui para a redução das taxas de incidência e de mortalidade por meio do aumento da cobertura e da organização do programa de rastreio. O HPV testing realiza análise de DNA, importante na identificação dos tipos oncológicos, o uso combinado com Papanicolau aumenta a sensibilidade do exame e é recomendado pelo FDA em mulheres de 30 a 65 anos a cada 5 anos. O careHPV testing system analisa a reação em cadeia da polimerase (PCR), é mais fácil de aplicar, rápido e de menor custo. Conclusão: O câncer de colo uterino é uma neoplasia maligna que pode ser prevenida por métodos de investigação aplicados de forma adequada. Apesar do HPV testing e careHPV testing system serem encontrados nesta pesquisa como meios de detecção do patógeno causador da doença mais eficazes, o meio de investigação mais acessível à população geral no Brasil é o papanicolau. Entretanto, esse método de rastreamento encontra diminuição de eficácia em países com sistema de saúde precário.

Assessment under Covid-19: Exploring Undergraduate Students’ Attitudes towards Their Online Thesis Proposal Presentations vs. Face-to-face

This study conducted in an EFL setting investigates students’ perception of the thesis proposal presentation in an online format due to safety concerns during the Covid-19 pandemic. Fifty-five students aged 20-22 years old, level B2-C1 in English, in their fourth year of a Business Informatics Bachelor’s programme at HSE University, Moscow, were surveyed regarding their end-of-course assessment experience, which involved a Skype online presentation, rather than the usual face-to-face presentation. Data were collected using a researcher-made questionnaire consisted of 3 sections and 12 items. A mixed-method approach using quantitative and qualitative data was employed. The findings indicate that emergency transition to the new format did not affect students’ satisfaction or results of the presentation. Overall, students were more than satisfied with the online format, and the results were similar, if not better, than in previous years. To minimise the disadvantages of this format, recommendations for teachers and students were offered. This study might offer new insight on the most appropriate and beneficial oral testing system for students and staff.

Development of the Architecture of the System of High-Load Testing

Testing system performance and its importance at the same time is difficult to overestimate or underestimate. It would be much more correct to talk about the timeliness of this activity. Virtually any digital sys- tem built on modern approaches and technologies can work without any critical problems with its own performance. At the same time, for any system, especially when it becomes popular, it is very likely that there will be a time when it will not be able to cope with the ever-increasing load and become unstable. However, most companies that develop and maintain their own digital solutions – from websites to any other digital systems – often focus primarily on the functionality of the system and its compliance, rather than on the performance of the system as a whole. Such intentions are quite natural, because the system must properly perform the functions expected of it. When companies start to face performance problems, they try not to optimize the software as soon as possible, but to add more capacity – vertical and horizontal scaling. This strategy works, but it has limitations. After all, the addition of additional resources cannot be endless and sooner or later rests either on the architecture of the system, or in the capabilities of the company itself, and so on.Therefore it is recommended to carry out stress testing in advance, plan time and resources to have enough time to correct errors, and generally understand the boundaries of the system. At the same time, in order to organize full-fledged stress testing, trained specialists, tools and infrastructure are needed, especially when we are talking about heavy workload.As part of this work, an analysis of various tools for the implementation of stress testing and performance testing, scaling of such tests and centralized reporting of metrics. As a result, approaches and principles for the construction of a modern architecture for the implementation of the load testing subsystem in the continuous supply of code were proposed.

The Selection and Optimum Well Testing Practices to Achieve Zero Flaring & Venting in Malaysian Water for a Petronas Field Development

Increased HSE concerns and global economic efficiency from well testing activities especially on its environmental impact have left several oil and gas industries’ facing critical challenges to develop and monetize oil reserves. Some of these challenges include handling well effluents from well test unloading operations after well completion with high contaminants such as H2S and CO2 which will exacerbate environmental impact to safety, pollution, and oil spill risks. In addition, mitigation to environmental impact will be constrained to limited deck space and topside loads for offshore wellhead facilities and eventually restricts the footprint of well test unloading equipment. The scope of the paper is to examine the evolution of well deliverability testing from conventional well test facilities’ flaring practices to contemporary smokeless and zero flaring operations applied in a giant sand stones oil field in Malaysian water, which is surrounded by a world class environmentally protected marine and coastal ecosystem. The zero-flaring approach allows a demonstration of the safety & emission reduction, cost saving, technical viability, and economic benefits over traditional flaring techniques for 20 to 30 well testing during the life of field. Previous wells clean up method require flaring of oil and gas before the production facilities and flow lines were operational.commissioned. The application of environment friendly well testing system using the completed flow lines and production facilities enable zero-flaring option to be technically and economically viable. Zero-flaring well testing system provides several attractive benefits, with potential reduction in flaring equivalent of ±1000 barrels of oil, pollution avoidance, 40 - 50% schedule reduction and over 40% reduction in total project costs for the field development..

Evaluation of the Sensitivity of Various Reinforcement Patterns for Structural Carbon Fibers to Open Holes during Tensile Tests

This paper is devoted to the experimental study of polymeric composite specimens, with various types of reinforcement, in order to evaluate the breaking strength of specimens with open holes when undergoing uniaxial compression and tensile tests. Four types of interlaced 3D woven preforms were considered (orthogonal, orthogonal combined, with pairwise inter-layer reinforcement, and with pairwise inter-layer reinforcement and a longitudinal layer), with a layered preform used for comparison. Tensile tests of solid specimens without a hole, under ASTM D 3039, and of specimens with an open hole, under ASTM D 5766, were carried out using the Instron 5989 universal electromechanical testing system. Movements and strains on the specimen surface were recorded using a Vic-3D contactless optical video system and the digital images correlation method (DIC). For all the series of carbon fiber tension specimens, strain and stress diagrams, mechanical characteristics, and statistical processing for 10 specimens were obtained. The paper evaluated deformation fields for certain points in time; the obtained fields showed an irregular distribution of deformation and dependency on types of reinforcing fibers. A coefficient of strength variation is introduced, which is defined as a ratio of the ultimate stress limits obtained on solid samples with and without open holes. Within the framework of ASTM D 5766, when calculating the ultimate stress, the hole is not taken into account, and the paper shows that for certain structures a hole cannot be excluded. The hole size must not be neglected when calculating the ultimate stress.