bluuebunny/crossref_metadata_2025 huggingface dataset:
Infográficos como recurso auxiliar do processo de aprendizagem de estudantes do ensino médio
Authors: Oliveira Karla , Cunha Kátia
Published: February 2021

Mudanças observadas no cenário da educação através da utilização de recursos midiáticos vislumbram as múltiplas formas de aprender e disseminar o conhecimento, buscando adequar as ferramentas surgidas em outros contextos para aplicar no âmbito da sala de aula, como os infográficos. Dessa maneira, a pesquisa tem por objetivo analisar a percepção dos estudantes sobre a criação e utilização de infográficos como recurso para auxiliar a aprendizagem. Fundamenta-se nos seguintes autores: Charlot (2000), Meireu (1998), Horn (1998), Colle (2004), Behrens (2005), Minervini (2005), Schmitt (2006), Leontiev (1978; 2006) entre outros. Quanto a metodologia trata-se de uma pesquisa descritiva, a qual foi desenvolvida em uma escola da rede pública estadual de Pernambuco, na disciplina de Química, no segundo e terceiro ano do ensino médio. O estudo utilizou uma sequência didática (SD) de acordo com Zabala (1998). Participaram da SD 43 estudantes do segundo ano e 36 do terceiro ano. A SD foi proposta em quatro etapas, a primeira apresenta uma abordagem sobre infográficos, a segunda é o momento prático em que os estudantes constroem os infográficos, a terceira é da exposição dos infográficos construídos e o processo de avaliação, e a quarta etapa culmina com aplicação do questionário com cinco questões objetivas. Todos os estudantes participaram da SD, exceto da etapa do questionário que foi aplicado por amostragem com 15 estudantes do segundo ano e 15 do terceiro ano. Os resultados demonstraram que 07 educandos do segundo e 11 do terceiro conheciam sobre infográfico, mas não sabiam construí-lo; em relação ao recurso auxiliar na aprendizagem, 07 estudantes do segundo e 10 do terceiro responderam que auxilia de forma parcial; no que se refere aos aspectos mais apontados na criação de infográficos os mais citados foram: autonomia, curiosidade e criatividade. As dificuldades expressas foram em relação à organização das informações nos modelos dos aplicativos/programas. Portanto, os infográficos emergem como uma ferramenta inovadora, pois os estudantes sentem-se atraídos por essa nova forma de conduzir o aprendizado, no entanto, ainda estão pouco habituados ao recurso o que requer mais exploração para integrá-lo às situações escolares.
Elaboração e implementação da produção técnica educacional: um guia prático e visual para “O ensino da matemática na educação infantil à partir da compreensão da cognição numérica”
Authors: Sanchez Júnior Sidney , Blanco Marília
Published: February 2021

Os conhecimentos matemáticos estão presentes na vida da criança desde o seu nascimento, o que torna o envolvimento com números algo natural; no entanto, muitas crianças apresentam ansiedade à matemática e avaliações brasileiras têm demonstrado resultados não satisfatórios na aprendizagem desta disciplina. O Manual Ilustrado: “Um guia prático para o ensino de Matemática na Educação Infantil a partir da compreensão da Cognição Numérica” propõe caminhos que contribuem para o ensino da Matemática na Educação Infantil, visto a escassez de materiais produzidos nesta temática. Sendo assim, o objetivo geral deste artigo consiste na descrição da elaboração e implementação das atividades contidas na produção técnica supracitada, discutindo a aplicabilidade de suas atividades e analisando a percepção dos professores da educação Infantil quanto a sua contribuição para sua prática de ensino e seus conhecimentos em relação à Cognição Numérica. Os resultados da pesquisa revelam uma análise positiva do trabalho desenvolvido, aferindo que o Manual Ilustrado é aplicável na Educação Infantil e pertinente à realidade dos Centros Municipais de Educação Infantil, constituindo-se como um material facilitador e potencializador de aprendizagens, bem como na formação de professores. Ao professor que ensina Matemática na Educação Infantil, ressalta-se a importância da compreensão da Cognição Numérica para que tenham subsídios para sua prática e uma intervenção de qualidade.
Evasão nos cursos de engenharia: um olhar para os trabalhos do COBENGE de 2000 a 2014
Authors: Godoy Elenilton , Almeida Eustáquio
Published: February 2021

Este artigo tem como objetivo estudar a evasão no curso superior de Engenharia a partir dos trabalhados apresentados no Congresso Brasileiro de Educação em Engenharia (COBENGE), no período compreendido entre os anos de 2000 a 2014. O período escolhido para analisar os trabalhos do COBENGE coincide com o início da expansão do ensino superior no país em virtude de investimentos políticos e econômicos que contribuíram para a democratização da educação nacional. Teoricamente fundamenta-se em estudos que tratam sobre a evasão no Ensino Superior. Metodologicamente insere-se numa abordagem mista, pois a modalidade de pesquisa foi o estado da arte e a análise dos dados seguiu a abordagem estatística. A análise indicou que se faz necessário acolher os alunos, oportunizando ambientes em que eles possam preencher as lacunas conceituais advindas de uma possível formação educacional básica deficiente.
An open-source, citizen science and machine learning approach to analyse subsea movies
Authors: Anton Victor , Germishuys Jannes , Bergström Per , Lindegarth Mats , Obst Matthias
Published: February 2021

The increasing access to autonomously-operated technologies offer vast opportunities to sample large volumes of biological data. However, these technologies also impose novel demands on ecologists who need to apply tools for data management and processing that are efficient, publicly available and easy to use. Such tools are starting to be developed for a wider community and here we present an approach to combine essential analytical functions for analysing large volumes of image data in marine ecological research.

This paper describes the Koster Seafloor Observatory, an open-source approach to analysing large amounts of subsea movie data for marine ecological research. The approach incorporates three distinct modules to: manage and archive the subsea movies, involve citizen scientists to accurately classify the footage and, finally, train and test machine learning algorithms for detection of biological objects. This modular approach is based on open-source code and allows researchers to customise and further develop the presented functionalities to various types of data and questions related to analysis of marine imagery. We tested our approach for monitoring cold water corals in a Marine Protected Area in Sweden using videos from remotely-operated vehicles (ROVs). Our study resulted in a machine learning model with an adequate performance, which was entirely trained with classifications provided by citizen scientists. We illustrate the application of machine learning models for automated inventories and monitoring of cold water corals. Our approach shows how citizen science can be used to effectively extract occurrence and abundance data for key ecological species and habitats from underwater footage. We conclude that the combination of open-source tools, citizen science systems, machine learning and high performance computational resources are key to successfully analyse large amounts of underwater imagery in the future.
Changement de nom de l’organisation et identification organisationnelle. Exploration dans une entreprise tunisienne de télécommunications
Authors: Gharsi-Missaoui Manel , Zaddem Ferid
Published: February 2021

Bien que les recherches sur le changement du nom de marque 1 de l’organisation soient du ressort du marketing, ce bouleversement affecte également l’organisation en interne. Dans ce travail, nous étudions les effets de ce changement sur l’identification organisationnelle. Notre ambition est de comprendre comment l’identification à l’organisation peut être affectée par le changement de son nom qui est «  l’expression la plus simple de l’identité  » (Giget, 1989 : 25). Pour répondre à cet objectif, nous avons mené une étude de cas exploratoire dans une entreprise tunisienne de télécommunications. Les résultats de notre recherche montrent que le degré d’identification organisationnelle suite à un tel changement est ambivalent. Ainsi, une diversité d’attitudes et de facteurs liés au changement de nom semblent conduire à une ambivalence du sentiment d’identification à l’entreprise.
Les mécanismes internes de gouvernance dans les institutions africaines de microfinance : synergie et effets sur la performance globale
Authors: Chabi Bertin
Published: February 2021

L’objectif de cet article est d’apporter une contribution à la gouvernance de l’entreprise en mobilisant le contexte sénégalais à travers ses institutions de microfinance (IMF). Nous avons cherché à identifier les interrelations entre les mécanismes internes de gouvernance (la forme juridique et les caractéristiques du conseil d’administration) en expliquant leur impact sur les performances financière et sociale des IMF. En mobilisant une méthodologie quantitative, nous avons mis en évidence deux types de résultats. D’une part, la forme juridique est substituable à certaines caractéristiques disciplinaires du conseil d’administration telles que la taille du conseil d’administration (CA), les comités spécialisés du CA. D’autre part, les effets de complémentarité entre certaines variables du CA et les effets de substituabilités. Par ailleurs, après spécification des modèles de régression, nous parvenons à deux conclusions principales. Premièrement, les CA de petite taille et le mode de fonctionnement du CA garantissent une meilleure performance financière des IMF. Deuxièmement, la forme juridique, le style de gouvernance et la plus grande taille des conseils sont déterminants pour expliquer la performance sociale des IMF.
Balade en a-diction. Le corps comme dialectique du vide et du manque
Authors: Lallemand Damien
Published: February 2021

Construire une relation thérapeutique avec un être pour qui les mots font défaut exige de la part du clinicien des qualités de didacticien. Dans un jeu de distances fluides, porté par un transfert tidal, le thérapeutique en addiction engage le clinicien dans ses dires, ses paroles, ses mots, son être, en avant de lui-même. S’avancer, il le peut à condition de maintenir le retrait et l’ouverture nécessaires, pour que l’autre, le patient, puisse s’inscrire dans l’espace inauguré pour lui, avec lui.
Quelle psychiatrie d’aujourd’hui ?
Authors: Firpi Sébastien
Published: February 2021

Ces quelques lignes ont été élaborées au fur et à mesure d’une expérience clinique et institutionnelle traversée notamment en psychiatrie publique. Sa rédaction s’est tissée dans l’après-coup de l’application de la loi Hôpital, patients, santé, territoires conjoint aux réminiscences de rappel des transformations institutionnelles du secteur social et médico-social. Refonder un collectif de soin à visée institutionnelle et démocratique ne peut se prévaloir de quelques « accords » provenant du corps politique, mais implique une réflexion constante critique des processus économiques et sociaux joignant scientisme et politique contemporaine, afin d’en éclairer leurs effets aliénants d’asservissement. Soignants comme citoyens, nous avons le choix de ne pas en être dupes, le contexte actuel lié à la « crise sanitaire » l’ayant révélé si vivement. Cette tentative d’éclairage écrite en 2018-2019 se réfère à de nombreux travaux engagés depuis plusieurs années pour aider à poser la question de la psychiatrie publique que nous désirons.
« Engagez-vous, rengagez-vous qu’y disaient ! »
Authors: Ferrand Laure
Published: February 2021

Vous avez dit engagement ? L’article propose une analyse de l’utilisation par la novlangue néolibérale du terme « engagement ». Si l’on identifie aisément certains termes de la novlangue, celui d’engagement passe souvent sous les radars. Pourtant, il concentre toutes les logiques à l’œuvre dans les organisations du travail et bien au-delà : la survalorisation de l’individu pour accompagner la mise en concurrence de tous contre tous, du petit geste contre la mobilisation collective et les rapports de domination. Au final, dans la novlangue, l’engagement devient synonyme de renoncement.
Être constructifs et positifs ensemble
Authors: Martin du Pont Héloïse , Maraquin Carine
Published: February 2021

Une mère, militante active, nous fait part de la philosophie de sa famille, notamment construite avec leur expérience de la maladie de leur fille P. Elle et son mari essaient de déployer leurs valeurs de respect et d’honnêteté dans leurs relations aux professionnels qu’ils rencontrent sur leur parcours, des soignants, des enseignants. Ils s’estiment chanceux de pouvoir s’appuyer sur des professionnels qui les écoutent, les soutiennent, respectent leurs choix. Leur famille dans son ensemble a été prise en compte.
Benefits of Affordable Robotic Pet Ownership in Older Adults With Dementia
Authors: Hammarlund Rebecca A. , Whatley Kari L. , Zielinski Mark H. , Jubert Jean Claude
Published: February 2021

The current study investigated the impact of affordable robotic pet ownership on agitation, quality of life, and depression in older adults with dementia. Data are reported for five adults with dementia receiving day services at an all-inclusive care center for older adults (one male; mean age = 82.8 years). Data were collected three times to obtain baseline (Time 1 to Time 2) and post-intervention (Time 2 to Time 3) scores. Self-reported quality of life and depression symptoms improved post-intervention, but not during baseline. Caregiver-reported agitation did not change consistently across participants during baseline or post-intervention. Simple ownership of affordable robotic pets may be a feasible option to improve quality of life and affective experiences in individuals with dementia. Further work with larger samples should examine whether a combination of ownership and structured activity would produce changes more perceptible to caregivers. [
Journal of Gerontological Nursing, 47
(3), 18–22.]
Impact of Delayed Time to Treatment on Visual Outcomes in Neovascular AMD: Data From the HARBOR Study
Authors: Goldberg Roger A. , Hill Lauren F. , Davis Tatiana , Ruiz Carlos Quezada
Published: February 2021

BACKGROUND AND OBJECTIVE:

To determine the potential impact on visual outcomes of delayed treatment initiation in patients with neovascular age-related macular degeneration (nAMD).

PATIENTS AND METHODS:

Post hoc analysis of anti-vascular endothelial growth factor treatment-naïve patients with nAMD from HARBOR. Time to treatment was defined as first ranibizumab injection date minus screening date. Comparisons were made between the prompt (≤ 6 days) versus delayed (> 10 days) treatment groups. Main outcome measures were best-corrected visual acuity (BCVA) change over time, BCVA, number of ranibizumab injections, and proportion of 3-line gainers/losers.

RESULTS:

In HARBOR, more than 50% of patients received their first injection within 7 days of screening, with mean (median) time to treatment of 4.6 (5) and 15.9 (14) days for the prompt and delayed treatment groups, respectively. Mean (95% confidence interval [CI]) BCVA change from baseline to Month 24 was 9.1 (7.4–10.8) and 8.8 (6.7–10.8) Early Treatment Diabetic Retinopathy Study letters in the prompt (n = 395) and delayed (n = 230) treatment groups, respectively. Mean (95% CI) total number of ranibizumab injections for the as-needed arms was 12.4 (11.6–13.3) and 11.4 (10.3–12.4) for the prompt and delayed treatment groups, respectively.

CONCLUSION:

In HARBOR, time from screening to first ranibizumab injection did not seem to significantly affect mean BCVA change or number of injections.

[
Ophthalmic Surg Lasers Imaging Retina
. 2021;52:62–69.]
MFRP
-Related Nanophthalmos-Retinitis Pigmentosa-Foveoschisis-Optic Disc Drusen Syndrome
Authors: Marques João Pedro
Published: February 2021

[
Ophthalmic Surg Lasers Imaging Retina.
2021;52:110.]
An a posteriori error estimator based on least-squares finite element solutions for viscoelastic fluid flows
Authors: Lee Hsueh-Chen , Lee Hyesuk
Published: February 2021

We present a posteriori error estimator strategies for the least-squares finite element method (LS) to approximate the exponential Phan-Thien-Tanner (PTT) viscoelastic fluid flows. The error estimator provides adaptive mass weights and mesh refinement criteria for improving LS solutions using lower-order basis functions and a small number of elements. We analyze an a priori error estimate for the first-order linearized LS system and show that the estimate is supported by numerical results. The LS approach is numerically tested for a convergence study and then applied to the flow past a slot channel. Numerical results verify that the proposed approach improves numerical solutions and resolves computational difficulties related to the presence of corner singularities and limitations arising from the exorbitant number of unknowns.
Stability and Hopf bifurcations in a competitive tumour-immune system with intrinsic recruitment delay and chemotherapy
Authors: Tang Qingfeng , Zhang Guohong
Published: February 2021

In this paper, a three-dimensional nonlinear delay differential system including Tumour cells, cytotoxic-T lymphocytes, T-helper cells is constructed to investigate the effects of intrinsic recruitment delay and chemotherapy. It is found that the introduction of chemotherapy and time delay can generate richer dynamics in tumor-immune system. In particular, there exists bistable phenomenon and the tumour cells would be cleared if the effect of chemotherapy on depletion of the tumour cells is strong enough or the side effect of chemotherapy on the hunting predator cells is under a threshold. It is also shown that a branch of stable periodic solutions bifurcates from the coexistence equilibrium when the intrinsic recruitment delay of tumor crosses the threshold which is new mechanism, which can help understand the short-term oscillations in tumour sizes as well as long-term tumour relapse. Numerical simulations are presented to illustrate that larger intrinsic recruitment delay of tumor leads to larger amplitude and longer period of the bifurcated periodic solution, which indicates that there exists longer relapse time and then contributes to the control of tumour growth.
Preliminary investigation of possible effects of mineral clay treatment applied to oils produced from olives: focus on moisture removal and compositional changes
Authors: Issaoui M. , Mosbahi M. , Barbieri S. , Flamini G. , Bendini A. , Ascrizzi R. , Gallina Toschi T. , Hammami M.
Published: February 2021

In this preliminary study, two non-filtered virgin olive oils (one freshly produced VOO-N; one VOO-O stored for one year) were subjected to moisture removal with mineral clay (raw or activated) and analyses were performed to attest possible effects on the quality of the product. The results demonstrated that the treatment of oil with mineral clay at 36-38 °C had no negative effect on the basic quality parameters or on the volatile comound profile. On the other hand, a significant decrease in the water amount as well as in pigments was observed in the samples subjected to this kind of treatment, in particular with raw clay. Regarding the colour measurement, the lightness (L) as well as the consumers’ acceptability exhibited a marked increase when oils were treated with raw clay.
Shelf-life of Moroccan prickly pear (Opuntia ficus-indica) and argan (Argania spinosa) oils: a comparative study
Authors: Gharby S. , Guillaume D. , Nounah I. , Harhar H. , Hajib A. , Matthäus B. , Charrouf Z.
Published: February 2021

Cactus seed oil is gaining considerable popularity in the cosmetic industry. To estimate cactus seed oil’ industrial as well as domestic ease of use, we investigated the oxidative stability of Moroccan cactus seed oil under accelerated aging conditions. In addition, we compared cactus seed oil stability to that of argan oil, a popular and well-established cosmetic oil, under the same conditions. Cactus seed oil is much more sensitive to oxidation than argan oil. Its shelf-life can be estimated to be no longer than 6 months at room temperature. Such instability means that the preparation process for cactus oil must be carried out with great care and cactus seed oil needs to be protected once extracted.
Deposition of Submicron Particles by Chaotic Mixing in the Pulmonary Acinus
Authors: Tsuda Akira , Henry Frank S.
Published: February 2021

In this review, the authors outline the evidence that emerged some 30 years ago that the mechanisms thought responsible for the deposition of submicron particles in the respiratory region of the lung were inadequate to explain the measured rate of deposition. They then discuss the background and theory of what is believed to be the missing mechanism, namely chaotic mixing. Specifically, they outline how that the recirculating flow in the alveoli has a range of frequencies of oscillation and some of these resonate with the breathing frequency. If the system is perturbed, the resonating frequencies break into chaos, and they discuss a number of practical ways in which the system can be disturbed. The perturbation of fluid particle trajectories results in Hamiltonian chaos, which produces qualitative changes in those trajectories. They end the review with a discussion of the effects of chaotic mixing on the deposition of inhaled particles in the respiratory region of the lung.
The Ultimate Data Flow for Ultimate Super Computers-on-a-Chip
Authors: Milutinović Veljko , Kotlar Miloš , Ratković Ivan , Korolija Nenad , Djordjevic Miljan , Yoshimoto Kristy , Valero Mateo
Published: February 2021

This chapter starts from the assumption that near future 100BTransistor SuperComputers-on-a-Chip will include N big multi-core processors, 1000N small many-core processors, a TPU-like fixed-structure systolic array accelerator for the most frequently used machine learning algorithms needed in bandwidth-bound applications, and a flexible-structure reprogrammable accelerator for less frequently used machine learning algorithms needed in latency-critical applications. The future SuperComputers-on-a-Chip should include effective interfaces to specific external accelerators based on quantum, optical, molecular, and biological paradigms, but these issues are outside the scope of this chapter.
Effect of Solution Treatment on Ageing Behaviour of Al-Mg-Si-Sn Alloy
Authors: Baruah Monoj , Borah Anil
Published: February 2021

In this study both natural ageing (NA) and artificial ageing (AA) behaviour of Al-Mg-Si aluminium alloy having trace addition of 0.04 wt.% Sn (Tin) was studied at different solution heat treatment (SHT) temperature and time, ageing time and temperatures. Microstructural analysis was performed to identify the intermetallic phases. It was observed that peak NA hardness strongly depends on the SHT temperature and time. SHT at 530 for 0.5 hour, slows down the peak NA hardness attaining time of the alloy to a maximum of 5 days. But as the SHT time increases to 3.5 hours, the peak NA hardness attaining time reduced to 1 day. Alloy SHT at 530 for 1 hour attain a maximum peak hardness of HRB 24 during 3 days of NA. Artificial ageing improved the hardness of the NA alloy to a maximum of HRB 41 during 12 hours of ageing at 190 . The overall hardness of Al-Mg-Si-Sn as-cast alloy increases by 32 % during ageing process.
An Influence of Oxygen Flow Rate on Structural, Optical and Tribological Properties of Molybdenum Oxide Thin Films
Authors: Dave Divyeshkumar P. , Patel Akshay M. , Chauhan Kamlesh V. , Rawal Sushant K.
Published: February 2021

The influence of oxygen flow rate is examined on structural, optical and tribological properties of molybdenum oxide films deposited by reactive magnetron sputtering. The films were characterized by X-ray diffraction, scanning electron microscope (SEM), and contact angle measurement system. The optical properties of the films were measured by UV-Vis-NIR spectrophotometer and transmittance of ∼73% in the visible region of the spectrum was achieved. The band gap increases with increases in oxygen gas flow rate. AFM figure illustrates that the roughness of surface increases as oxygen flow rate increases. As oxygen increases wear rate and COF decreases while at the 18 sccm the lowest wear rate found.
Characterization of Pyrolytic Oil and Char Obtained from Sugarcane Bagasse Pyrolysis
Authors: Saif Ahmed Gaber H. , Wahid Seddik S. , Ali Mohamed R.O.
Published: February 2021

Sugarcane bagasse pyrolysis in a fixed-bed reactor has been studied. The Pyrolytic oil and char obtained were characterized to determine their feasibility as fuels and chemical reagent in other processes. The runs were performed under the following conditions: temperature from 350°C–600°C, sample size of 0.5–1 mm, and an inert gas flow rate of 200 cm3/min. The study aimed to characterize the obtained oil and char to determine their feasibility as source of energy and chemical product. The product has been characterized by different techniques including gas chromatography–mass spectrometry (GC–MS), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX). The obtained bio-oil exhibited a molecular formula of CH1.03O0.28 N0.012 and a higher heating value (HHV) of 27.68 MJ/kg. These results indicated that it could be used after refining as a source of fuel and produced a chemical product. In addition, the obtained biochar (HHV = 31.53 MJ/kg) can be used as a solid fuel.
Properties of Compressed Interlock Earth Blocks Manufactured from Locally Available Lateritic Soil for Low Cost Housing Projects
Authors: Dmdok Dissanayake
Published: February 2021

This investigation was carried out to identify the engineering properties of compressed interlock earth blocks manufactured from locally available lateritic soil and introduce to use the manufactured soil blocks to minimize the material and finishing cost for the low cost housing projects. The soil samples used in this study were well-graded lateritic sandy soil which has the composition of 1.9% gravel, 94% sand and 4.1% silt / clay. These soil samples were passed through the 100-mesh sieve and mixed with ordinary Portland cement to prepare the admixture. While compressing through a hydraulics jack by varying the compositions and the volume of soil-cement admixtures, compaction soil blocks were manufactured in a locally fabricated 250 mm x125 mm x100 mm standard steel mould. The manufactured soil blocks allowed to cure while spraying small quantity of water and covering with polythene for 28 days. Average compressive strengths of soil blocks made with 5% cement with 1.6:1 and 1.8:1 volume compactions were 1.3 Mpa and 1.9 Mpa, respectively. However, both compressive strength values were less than the standard limits of 2.8 MPa stated in SLS 1382:2009, local standards for soil blocks used for construction industry. However, soil blocks made with 10% cement under same compaction ratios attained compressive strengths of 3.0 MPa and 3.6 MPa respectively and it is above the required standards limits. However, 15% and 20% cement containing earth blocks have much higher compressive strengths but increase the cost of production. Regression analysis results confirmed the strong correlation between cement content and the compressive strength of the soil bricks. The soil bricks manufactured with more than 12.06% cement soil mix by maintaining compaction ratio into 1.6:1 or Soil bricks manufactured with more than 5.16% cement mix by maintaining compaction ratio into 1.8:1 will produce standards soil bricks for construction industry and these results further confirmed that wet and dry compressive strength of soil bricks will increase with increasing the compaction ratio and the cement content. However, when considering the compressive strength, water absorption level and cost effectiveness, soil bricks manufactured by maintaining compaction ratio into 1.8:1 with more than 5.16% cement mix will produce required standards cost effective soil bricks for construction industry.
Ultrasonic Inspection for Microstructural and Mechanical Properties of Ductile Cast Iron
Authors: Özdemir Özer , Gürgen Selim , Kushan Melih Cemal
Published: February 2021

Ultrasonic inspection is a well-known method in non-destructive testing. Based on the changes in the ultrasonic sound speed, tested materials are evaluated in terms of internal defects. In addition to flaw detection, ultrasonic testing is used in the material characterization of ductile cast iron. Graphite shape detection has been widely investigated by ultrasonic inspection in literature. However, most of the measurements has been conducted at single frequencies. In this work, three different nodulizer included casting operations were carried out to produce ductile cast irons having various graphite morphologies. A wide frequency range of 1.25-10 MHz was selected in the ultrasonic inspection. In addition to graphite morphology analyses, the relationship between ultrasonic sound speed and mechanical properties was studied. In the mechanical analyses, hardness and tensile testing properties were investigated for the specimens. From the results, ultrasonic sound speed exhibits a considerable dependency to the graphite morphology. In addition to a good graphite detection capability, ultrasonic inspection exhibits promising results for predicting the mechanical properties such as hardness, elastic modulus, yield strength and tensile strength. It is also found that there is a slight increase in the ultrasonic sound speed by increasing the frequency, although sound speed is independent from this parameter.
Structure Formation of Butt Joints Made of Aluminum Alloys to Ensure the Quality of Mechanical Engineering Products
Authors: Sharapova Dinaida M. , Sharapov Mikhail G. , Sharonov Nikolay I.
Published: February 2021

The article discusses the problems of ensuring high-quality formation and normative properties of butt joints of the 1560M and 1980T1 (AMg6 and B48) aluminum alloys as applied to engineering. A method is proposed for joining materials by means of EBW using an electron beam sweep. Homogeneous and dissimilar joints have been investigated, heat treatment of joint from the 1980T1 alloy and a dissimilar joint from the 1560M + 1980T1 alloys is recommended. The paper also presents the results of mechanical properties testing, the corrosion resistance and the delayed fracture tests. A welding technology that makes it possible to obtain high-quality butt-welded joints from aluminum alloys in thicknesses up to 40 mm has been developed and implemented.
Influence of the Composition of Boriding Mixture on the Saturation of the Surface of Various Steels with Boron during High-Speed HFC-Boriding
Authors: Ishkov Alexey , Malikov Vladimir N. , Shegolev Alexander
Published: February 2021

The use of borate fluxes is an important component of the part hardening process by HFC-heating. The article discusses the possibility of using various coatings to saturate the surface of steel parts, as well as the features of using various boriding agents. Microstructures of the obtained boride coatings at various fractions of the boriding agent have been considered, and the areas of carbide inclusions and average thickness of the resulting coatings have been analyzed. The expediency of P-0.66 fused flux using and changes in the resulting coatings due to the changes in the mass fraction of this flux in various boriding mixtures have been investigated. Based on the obtained data on the microstructures of boride coatings, conclusions were made concerning the most appropriate compositions of boriding mixtures and the mass fraction of fused flux in their composition.
Increasing the Rigidity of Thin-Walled Machine Parts Made of Aluminium Alloys by Reducing its Grain Size by Two-Way Ultrasonic Smoothing
Authors: Chibukhchyan Hovhannes , Balasanyan Aram , Balasanyan Boris
Published: February 2021

The use of ultrasonic smoothing methods for metal sheet materials opens up new opportunities for improving their performance properties. The paper considers the possibility of increasing the axial stiffness of aluminium thin-walled machine parts by reducing the size of their grains and creating conditions for obtaining nanostructured formations. It has been found that the yield strength of the 8011 grade foil treated with two-way ultrasonic smoothing, depending on the depth of the hardened layer, microstructure and grain size, initially decreases to the middle section, and then increases to its largest value. According to a similar relationship, the relative elongation, i.e. the plasticity of a thin-walled part, changes which also confirms the possibility of formation of nanostructures in the studied layers. Experimental studies have established that the two-way ultrasonic treatment of multilayered plates made of aluminium 8011 grade foil with a thickness of 0.42 mm allows to provide high plasticity and to increase its axial rigidity up to 20.6%, thereby improving the manufacturability of complex machine parts from thin-walled plates by the methods of cold treatment.
Phase Formation in Contact Melting in a Cadmium-Indium System Doped with Sodium
Authors: Bagov A.M. , Khasanov A.I. , Zubkhadzhiev M.A.V.
Published: February 2021

This study is dedicated to application of x-ray methods to investigate phase formation in contact melting in a Cd-In system after introduction of a small admixture of sodium to cadmium, including cases of electrotransport. Formation of both two-and three-component intermetallic compounds has been established. An attempt is made to explain the results.
The Effect of Particle Sizes on the Concentration Dependence of the Surface Tension of Aqueous Suspensions of Bentonite
Authors: Dadashev R.Kh. , Dzhambulatov R.S. , Khasbulatova Z.S. , Talkhigova Kh.S.
Published: February 2021

The paper presents experimental results on the dependence of surface tension on the concentration of a suspension of bentonite (0 - 10% by weight). The isotherms σ of aqueous suspensions of bentonite are characterized by local minima in the concentration range of 3-4 mass% of the solid phase. It has been established that a decrease in the average particle size leads to the disappearance of the extremum on the surface tension isotherms. The data obtained led to the conclusion that the most important factors affecting the nature of the isotherms of the surface tension of bentonite suspensions are the degree of dispersion and the presence in the aqueous suspension of bentonite, both colloidal and coarse particles.
Analysis of the Structure of Viscous Oil Flow for the Development of a System to Prevent the Formation of Paraffin Deposits in Pipelines
Authors: Kopteva Alexandra V. , Dementyev Alexander , Koptev Vladimir
Published: February 2021

The detection of paraffin deposits in the systems of main oil pipelines today is a very important problem, since they lead to emergency oil spills, environmental disasters and economic losses both for the enterprise and for the country as a whole. This work is aimed at studying the physicochemical properties of asphaltic resin paraffins, as well as the mechanism of phase transition from liquid to crystalline. Such studies make it possible to estimate the absorption coefficient of the paraffin phase, which was previously not possible due to the complex nature of oil, consisting of hydrocarbons and many organic compounds of various molecular weights, and to provide high-precision non-contact measurements of the concentration of suspended asphalt-resin-paraffins in the oil flow in the pipeline. The analysis of the morphology and chemical composition of paraffins of various deposits is carried out, the dependence of the phase transition depending on the temperature gradient is determined.
Machinability of Heat-Resistant Titanium Alloys during Turning
Authors: Larionova Tatyana , Lyubomudrov Sergei A. , Larionov Evgeniy
Published: February 2021

The article discusses the properties and features of heat-resistant titanium alloys. The microstructure of a new titanium alloy VT41, its mechanical and service properties after various processing modes are presented. The main problems in the machining of difficult-to-machine titanium alloys are considered. The developed mathematical model of the formation of errors in turning titanium alloys, taking into account thermal deformations and dimensional wear of the cutting tool, elastic deformations of the technological system, is described. The paper presents the results of experimental research on turning of heat-resistant titanium alloy VT41 on a multi-parameter stand.
A huge abdomino-pelvis tumour in a prepubertal girl: A case report of dysgerminoma infiltrating both ovaries and uterus in an 11-year-old girl in Maiduguri
Authors: Farouk Abubakar Garba , Farate Abubakar , Wabada Samuel , Nkama Iro , Geidam Ado Danazumi
Published: February 2021

Dysgerminoma is one of the rare highly malignant ovarian germ cell tumour. It originate from undifferentiated germ cells that are similar to primordial germ cells, and it is identical to testicular seminoma in males. Despite the tumour being malignant, prognosis is excellent with surgery and adjuvant chemotherapy, with promising results concerning future fertility. In this case, we report an 11-year-old girl with abdominal swelling for 7 years. She had gross abdominal distension, with a huge palpable mass. Abdominopelvic ultrasound scan showed a huge heterogeneous mass measured 9.8 cm x 15.7 cm and computed tomography showed a huge lobulated mass measured 19.2 cm x 19.0 cm x 16.3 cm. Exploratory laparotomy and excision of the mass was done. Ovarian dysgerminoma are uncommon in prepubertal girls. Prognosis depends on the stage at presentation and histology. Multidisciplinary management with a Gynaecologists and Oncologists with joint decision on the need to maintain the child’s developmental and reproductive potential as much as possible should aimed at.
Huge symptomatic pedunculated uterine fibroid in pregnancy: Antepartum myomectomy and term delivery at a specialist hospital in Kano, Nigeria
Authors: Haruna Iman Usman , Tukur Jamilu , Takai Idris Usman , Mohammed Abdullahi Mustapha Miko , Bunawa Ali Abdurrahman
Published: February 2021

Myomas are common in pregnancy and can go unnoticed. One in ten patients, however, develops complications that would necessitate their removal. Myomectomy performed at caesarian section had come to the lime light over the last decade and recent literature have shown its safety. There is still paucity of literature on myomectomy performed during pregnancy. Our case was a 25 years old primigravida at 21 weeks with features of acute abdomen secondary to uterine fibroid which was diagnosed during pregnancy. She subsequently had antepartum myomectomy and a live birth at term via caesarean section.
Foam Rolling, Elbow Proprioception, Strength, and Functional Motor Performance
Authors: Ozden Fatma , Yesilyaprak Sevgi Sevi
Published: February 2021

Context

Foam rolling has recently been used frequently to increase flexibility. However, its effects on proprioception, strength, and motor performance are not well known. In addition, very few researchers have examined the effects of foam rolling on the upper extremity.

Objective

To investigate the effects of foam rolling on elbow proprioception, strength, and functional motor performance in healthy individuals.

Design

Randomized controlled clinical trial.

Setting

Exercise laboratory of School of Physical Therapy and Rehabilitation, Dokuz Eylul University.

Patients or Other Participants

Sixty healthy participants (mean age = 22.83 ± 4.07 years).

Intervention(s)

We randomly assigned participants to 2 groups: the foam-rolling group (FRG; 4 weeks of foam rolling for the biceps brachii muscle) or control group (CG; no foam rolling).

Main Outcome Measure(s)

We evaluated proprioception (joint position sense [JPS] and force matching), biceps brachii muscle strength, and functional motor performance (modified pull-up test [MPUT], closed kinetic chain upper extremity stability test [CKCUEST], and push-up test) at the baseline and at the end of the fourth and eighth weeks.

Results

The JPS at 45° of elbow flexion, muscle strength, CKCUEST, and push-up test results improved after foam rolling, and improvement was maintained at follow up (P < .017). Although the changes between groups for the results of proprioception and CKCUEST were similar among the 3 time points (P > .05), muscle strength improved from baseline to the second evaluation and from baseline to follow up (P < .001) in the FRG compared with the CG group (P = .004). The FRG group demonstrated better push-up test results than the CG group at the 3 time points (P = .040, P = .001, P < .001). Other data did not change (P values > .05).

Conclusions

Foam rolling was effective in improving elbow JPS at small flexion angles, biceps brachii strength, and some aspects of upper extremity functional motor performance. These effects were maintained at 4 weeks after application.
Hyperbaric oxygen therapy decreases mortality due to Fournier’s gangrene
Authors: Féres Omar , Feitosa Marley Ribeiro , da Rocha José Joaquim Ribeiro , Miranda Juliana Mamede , dos Santos Luciana Egydio , Féres Artur Cury , de Camargo Hugo Parra , Parra Rogério Serafim
Published: February 2021

There is no consensus about the role of adjunctive hyperbaric oxygen therapy (HBOT) in the management of Fournier’s gangrene. The aim of this study was to compare the evolution of patients with Fournier’s gangrene treated with all classical measures with and without adjuvant HBOT. A retrospective comparative study regarding the evolution of patients treated for Fournier’s gangrene was conducted in two periods. In period I, from 1990 to 2002, patients received standard treatments for Fournier’s gangrene, which consisted of surgical debridement, antibiotic therapy and intensive care. In period II, from 2012 to 2019, adjunctive HBOT was added to the classical management strategy. All patients were assigned into four groups according to the anatomical severity classification and the area affected after the first debridement. This classification ensured that the groups could be comparable. The total number of patients in this study was 197, and these patients were divided into control group (118/59.9%) and HBOT group (79/40.1%). The mean age, comorbidities, and anatomical severity classification were similar between the two groups. In period I, 34 out of 118 (28.8%) patients died, while in the HBOT group, 3 out of 77 (3.7%) patients died (P < 0.001). The use of adjuvant HBOT in combination with classical treatment was associated with reduced mortality. This study was approved by the Institutional Review Board and the Ethics Committee of Ribeirão Preto Medical School, University of São Paulo, Brazil (No. 08/2018) on May 2, 2018.
A new mechanistic approach for the treatment of chronic neuropathic pain with nitrous oxide integrated from a systems biology narrative review
Authors: Bessière Baptiste , Iris François , Milet Aude , Beopoulos Athanasios , Billoet Catherine , Farjot Géraldine
Published: February 2021

The limitations of the currently available treatments for chronic neuropathic pain highlight the need for safer and more effective alternatives. The authors carried out a focused review using a systems biology approach to integrate the complex mechanisms of nociception and neuropathic pain, and to decipher the effects of nitrous oxide (N2O) on those pathways, beyond the known effect of N2O on N-methyl-D-aspartate receptors. This review identified a number of potential mechanisms by which N2O could impact the processes involved in peripheral and central sensitization. In the ascending pathway, the effects of N2O include activating TWIK-related K+ channel 1 potassium channels on first-order neurons, blocking voltage-dependent calcium channels to attenuate neuronal excitability, attenuating postsynaptic glutamatergic receptor activation, and possibly blocking voltage-dependent sodium channels. In the descending pathway, N2O induces the release of endogenous opioid ligands and stimulates norepinephrine release. In addition, N2O may mediate epigenetic changes by inhibiting methionine synthase, a key enzyme involved in DNA and RNA methylation. This could explain why this short-acting analgesic has shown long-lasting anti-pain sensitization effects in animal models of chronic pain. These new hypotheses support the rationale for investigating N2O, either alone or in combination with other analgesics, for the management of chronic neuropathic pain.
Dental Students' Perception on the Impact of E-learning in Continuing Dental Education during the Current Pandemic Scenario
Authors: Samra Rupandeep Kaur , Nirola Ashutosh , Verma Anupama , Nagpal Archana , Thakur Malvika
Published: February 2021

Background:

On account of the pandemic SARS-CoV-2 (COVID-19), education in higher institutes was strongly affected and they were shut down. The education shifted from “face-to-face” learning to online learning in the dental universities. The aim of this study was to assess the students' perspective on the implementation of online learning due to COVID-19, using a questionnaire-based survey in India.

Materials and Methods:

The authors sent out an electronic survey to the undergraduate dental students from October 17, 2020 to October 25, 2020. The online questionnaire had a combination of multiple-choice, Likert scale, and open-ended questions which gave insight into the demographics, access to technological sources, didactic benefit, study habits, perceived issues with e-learning, conduction of examinations during the pandemic period, and their mental health. Students were also asked for their views on the inclusion of online learning in the future curriculum. Qualitative data was expressed as number and percentage. A comparison was performed using Chi-square test. Kruskal-Wallis test was done for Likert scale questions and Bonferroni test was used for post hoc comparisons.

Results:

Among 2319 dental students, 63.9% exclusively used smartphones and 8.5% used laptops for classes. The rest of the students used both devices. To access online resources, about 2262 (97.5%) had Internet connection. Only 943 students (40.7%) did not encounter any difficulty while engaging in online learning. About 1466 students (63.2%) appeared for examinations. About 1261 students appeared offline for both theory and practical examinations. Fifty-five percent of the participants felt offline examinations to be a better alternative. About 69.6% of students preferred “face-to-face” learning instead of solely online learning. Nearly 19.4% of students wanted online education to be continued, while 28.5% wanted to keep both offline and online courses in the future curriculum. Most frequently encountered problems were difficulty in adjusting to new learning styles, having to perform responsibilities at home, and poor communication between educators and learners.

Conclusion:

Students showed a little reticent attitude towards on the implementation of online learning and were hopeful of engaging in online learning after improvisation in the future curriculum.