bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the pressure wave velocity model of multiphase fluid in the annulus of dual-gradient drilling
Authors: Guo Xiucheng , Zhang Zhe
Published: October 2023

Dual-gradient drilling technology is difficult to detect and deal with well kick, which may cause safety problems such as well control. Once a well kick occurs, the pressure in the narrow annulus increases instantaneously, so it is particularly important to clarify the transmission law of pressure wave. Taking the pressure fluctuation in the annulus of double gradient drilling as an example, considering the boundary between the inner wall of the casing annulus and the outer wall of the drill string, the fluid resistance, the flow field distribution and the multiphase flow, this paper deduces and establishes the multiphase flow pressure wave velocity model in the annulus, and compares the calculation results with the pressure wave velocity model in the circular pipe. The research shows that when the casing and drill string are in the static condition with small roughness and little difference between them, the shear stress on the inner wall of the annulus and the outer wall of the drill string can be treated as equal, and the derivation of the annulus pressure wave velocity model can be simplified. The pressure wave velocity of multiphase flow in annulus is related to casing size, drill string size and multiphase fluid properties. Among them, the gas content is the main influencing factor. With the increase of the gas content, the pressure wave velocity decreases, but the decreasing range will gradually decrease. When the solid content is small, it has little effect on the pressure wave velocity.
Study on the effect of width and slope of large cross-section tunnel on critical velocity of fire
Authors: Liu Su
Published: October 2023

When a tunnel fire occurs, due to the difference of tunnel width and slope, both smoke countercurrent length distribution law and critical velocity will become different, and these two are very important parameters in tunnel longitudinal ventilation design. Therefore, for the design of smoke control and longitudinal ventilation of the tunnel, based on actual highway tunnel size, this paper established and ran a series of numerical simulations through FDS simulation software to study tunnel width and slope?s effect on smoke countercurrent length and critical velocity. The results of this paper show that smoke countercurrent length decreases with tunnel slope?s increase and increases with tunnel width?s increase. Through dimensionless analysis, the prediction formulas of smoke countercurrent length and critical wind speed of large cross-section tunnel about tunnel width, slope and height are modified and established. The research conclusions can provide a theoretical basis for the longitudinal ventilation design, smoke prevention and exhaust measures and personnel evacuation in large cross-section tunnel fires.
Experimental and numerical modeling of the heat generation characteristics of lithium iron phosphate battery under nail penetration
Authors: Yin Yanxin , Zhang Tao , Dai Zuoqiang , Wei Tao , Qiu Xiangyun
Published: October 2023

This study conducted nail penetration tests on 20 Ah prismatic LiFePO4 batteries and simulated the slow release of Joule heat and side reaction heat by combining a new thermal model with a parameter optimization method. The results indicate that the 50% and 80% SOC LiFePO4 batteries only release Joule heat under penetration, while the side reaction heat is acquired under 100% SOC besides Joule heat. Moreover, approximately 56.4% of the stored electrical energy is converted into Joule heat, which accounts for the majority of the total heat production of 100% SOC LiFePO4 battery under penetration, while side reaction heat accounts for only 6.4%. Furthermore, the exothermic side reactions of 100% SOC LiFePO4 battery under penetration can be effectively suppressed when the electrical energy release ratio is less than 0.52, or the convection coefficient between the battery and its surroundings exceeds 12 W/m2K. This numerical study expands the analysis of the heat generation characteristics of LiFePO4 batteries during penetration and provides practical guidance for system safety design.
Numerical study on flow and heat transfer characteristics in structured packed bed
Authors: Li Nan , Feng Peng , Cui Jie , Li Fan , Song Jiawei
Published: October 2023

The ANSYS software is introduced to reproduce the in-line and staggered sphere packed bed model. To investigate the influence of model on the heat transfer and flow characteristics in the high temperature packed bed, numerical simulations of pore-level was used to numerically appreciate the changes of pressure drop, temperature and velocity. The simulation values qualitatively agree with the experimental result. The results show that the pressure drop in high temperature packed bed increases significantly. The pressure drop increases about 3200 Pa when the inlet velocity is 0.33-0.73 m/s. The model has significant influence on the average temperature of solid and gas phases. Compared with the in-line arrangement, the heat wave transfer is slower and the temperature is slightly higher by 20 K in the staggered model. The average velocity in the structured packed bed increases and decreases periodically. In staggered model, the velocity disturbance is more significant. These findings are helpful for understanding transport phenomena in packed beds as well as the design of high efficiency reactors.
Swirl development and enhanced heat transfer analysis of ferrofluid in elliptical ducts under thermal-magnetic-flow fields coupling
Authors: Wang Cuihu , Zhang Wenquan , Rong Duo , Jia Zepeng , Gong Bin , Wu Jianhua
Published: October 2023

It is a new practical method to apply external magnetic field in magnetic
working fluid to enhance heat transfer. In this paper, the swirl flow and
heat transfer characteristics of ferrofluid in elliptical tubes under
thermal-magnetic-flow fields coupling have been studied by using the finite
volume method. The flow structure and secondary vortices evolution process
of magnetic nanofluid in elliptical ducts under the action of the magnetic
fields have been obtained. The effects of magnetic induction intensity and
the ratio of major axis to minor axis of elliptical pipe on the flow and
heat transfer performances have been main investigated. The results show
that there is obvious secondary flow (with four vortices or eight vortices)
on the cross section and the swirling flow is gradually formed due to the
coupling of thermal-magnetic-velocity fields. With the increase of the ratio
of major axis to minor axis, the heat transfer enhancement effect with the
application of external magnetic field is weakened. The comprehensive
performance of flow and heat transfer are better at lower Reynolds number
and higher magnetic induction intensity.
Investigation on the effect of injector modification on injector atomization and U-bend pulse detonation combustion characteristics
Authors: Wang Dingding , Zheng Longxi , Lu Jie , Tan Wenhao , Li Qing
Published: October 2023

In order to shorten the deflagration-to-detonation transition (DDT) distance of the pulse detonation combustion chamber, an experimental study of the effect of pneumatic atomization injector modification on atomization particle size amd gas-liquid two-phase U-bend pulse detonation combustion (U-PDC) chamber was carried out. Gasoline and air were used as fuel and oxidizer, and the atomization particle size was tested and the detonation characteristics of the U-PDC were obtained using the pneumatic atomization injector before and after the modification. The results show that the atomization size range of the injector before the modifica?tion is 111.6~152.9 ?m, after the modification of the injector atomization size range of 76.4~107.2 ?m, atomization size than before the modification is significantly reduced. The U-PDC using the injector before and after the modification can achieve stable operation in the range of 10~30 Hz, and the DDT distance shortened with the increase in frequency. At an operating frequency of 30 Hz, the DDT distance of U-PDC with the injector before modification is about 676 mm, and the DDT distance of U-PDC with injector after modification is shortened by 8.9% to about 616 mm. In addition, under the same operating conditions, due to the better atomization effect of the injector after modification, The fuel flow rate of U-PDC with the injector after modification is 5~10% smaller than that with the injector before modification when the average detonation pressure reaches its maximum value during the adjustment of fuel-flow.
Numerical investigation of the effects of volume forces on flame propagation characteristics in a rotating pipe
Authors: Gong Zhen , Li Benchi , Tang Hao
Published: October 2023

The combustion of fuel under intense volumetric forces has the potential to enhance the velocity of flame propagation. To investigate the influence of volumetric forces on the combustion process and the characteristics of flame propagation within fuel, this research paper conducted a numerical analysis of a 2-D rotating pipe subjected to varying volumetric forces. The findings reveal that, within a specific range, an augmentation in volumetric forces progressively elevates both the global and localized speeds of flame propagation. The primary rationale behind the heightened flame propagation speed under intense volumetric forces lies in the fact that the increase in such forces facilitates an enlargement of the interface area between the burned and unburned gases. This, in turn, fortifies the transfer of heat and the chemical reaction rate between the two, effectively shortening the duration of combustion and augmenting the speed of flame propagation. At exceedingly low volumetric forces, the pressure wave generated by combustion in the pipe exerts a certain influence on the speed of flame propagation and the progression of the flame
Experimental and numerical investigation of Rayleigh-Benard convection in rectangular cavity with motor oil
Authors: Zivkovic Predrag , Tomic Mladen , Ayed Sadoon , Barz Cristian , Sever Drago
Published: October 2023

Naturally flows have been the scope of the scientific research for centuries, Rayleigh-Benard convection being one of the leading. Many researchers have considered the flow patterns, boundary conditions, various cavities, nanofluids, theoretically, numerically, and experimentally. The flow was investigated in atmosphere and in nanofluids, in air, water, molten metals, non-Newtonian fluids. Almost all research focuses on 2-D or 3-D analysis of flow in laterally unlimited enclosures, as parallel plates or coaxial cylinders. In technical practice, only limited enclosures exist. This paper presents numerical and real experimental results for the test chamber with ratio 4?2?1 in x-, y-, and z direction, respectfully. The measurements were taken at fifteen different positions on the faces of the tank. Probes used are PT100 elements. As the chamber is limited in all directions, the results have shown strong influence of the lateral walls. The results are compared with the those obtained by IR camera. Various fluids were tested, and results for motor oil will be presented.
Experimental study of nucleate pool boiling with water in atmospheric pressure
Authors: Agma Onur , Yildiz Sebiha
Published: October 2023

This study experimentally investigated nucleate pool boiling heat transfer for a polished copper surface and water fluid couple under atmospheric pressure. The results were compared with the correlations in the literature. The experimental results were compared with the surface-liquid correlation constants Rohsenow, Pioro, Vachon, Griffith, and Das used for the temperature exceedance values. When the results of Griffith's correlation constant were compared with the experimental values, it was seen that it was the most appropriate correlation compared to other correlations, with a minimum and maximum error of 0.4-12%. In addition, Forster-Zuber, Pioro, Kutateladze old, Kutateladze new, Kruzhilin, and Cooper correlations were compared with experimental results regarding the heat transfer coefficient. Compared with the correlation proposed by Pioro for the heat transfer coefficient, it was calculated as the most suitable correlation with a minimum and maximum difference of 0.2-8%
Study on single-phase and two-phase flow and heat transfer characteristics of HFE-7100 in manifold microchannel heat sink with corrugated bottom
Authors: Cheng Jianping , Xu Hongsen , Tang Zhiguo , Zhou Pei
Published: October 2023

To solve the problem of high heat flux heat dissipation in microelectronic devices, a manifold micro-channel heat sink with corrugated bottom (CB-MMC) is pro-posed on the basis of the manifold microchannel heat sink (MMC). The flow and heat transfer characteristics of HFE-7100 in MMC and CB-MMC are investigated numerically. The results show that CB-MMC reduces the pressure loss and enhances the heat transfer performance in single-phase flow. The orthogonal test method is used to obtain structural design solutions with optimal thermal performance. It is observed that the temperature reduction is always at the expense of the increase of the pressure drop. In addition, the optimization parameters combination obtained through comprehensive evaluation of temperature and pressure drop through weight matrix ? optimized solution 19 (wavelength A = 800 ?m, am-plitude B = 40 ?m, channel depth C = 180 ?m, outlet width D = 300 ?m, channel width E = 25 ?m). Its Tave has decreased by 6.89?C, ?P decreased by 10.27 kPa. Moreover, the subcooled boiling flow and heat transfer performance in MMC and CB-MMC are comparatively studied. The results demonstrate that the dynamic behavior of vapor bubbles causes large pressure fluctuations, which further leads to small temperature fluctuations, and thus reduces the stability of the flow and boiling heat transfer. Compared with MMC, CB-MMC exhibits more stable two-phase flow and better boiling heat transfer.
Effect of method and media type for in vitro fertilization on equine (Equus ferus caballus) embryo development
Authors: Aryan Hussam , Mardenli Omar , Groza Ioan , Bogdan Liviu
Published: October 2023

Demonstrating the role of in vitro fertilization in the equine family, the current study aimed to monitor the rates of equine in vitro-fertilized and cleaved oocytes based on microdroplet and intracytoplasmic sperm injection (ICSI) methods. The fertilization process was carried out in four main media consisting of Tyrod?s albumin lactate pyruvate and TCM-199 (1:1): F (TCM-199); assigned for the ICSI method, FI (contained 0.01 mg/ml heparin + 0.01 ng/ml hypotaurine), FII (contained 0.3 mg/ml calcium chloride + 0.1 mg/ml magnesium chloride) and FIII (contained 0.05 mg/ml hypotaurine-epinephrine). The results indicated an increase in the fertilization rate by the ICSI method (65.71%) compared to the microdroplet method (39.25%) (p 0.04). The rates of unfertilized and degenerated oocytes in the ICSI method decreased, compared to the microdroplet method, to 8.57% and 25.72%, respectively; p< 0.001. The rate of fertilized oocytes in the FI medium increased to 47.61% (p< 0.05) compared to oocytes of FII and FIII treatments (37.64% and 30.00%, respectively). On in vitro culture, the rate of cleavage increased to 74.62% in the CI medium (SOF) compared to those in the CII medium (DMEM-F12) (61.29%); p <0.001. Zygotes cultured in the CII medium achieved a higher rate of blastocyst formation (30%) compared to those in the CI medium (26.31%); p< 0.001. Applying the ICSI method and SOF culture media led to high yields of equine embryos.
Psychologists as emergency first responders during a pandemic
Authors: Deshpande Abhijit , Pesic Anita , Boe Ole , Piotrowski Andrzej , Rawat Samir
Published: October 2023

nema
Monitoring Sleep and Scratch Improves Quality of Life in Patients with Atopic Dermatitis
Authors: Yasuda Ken-ichi , Ishiuji Yozo , Ebata Toshiya , Kogure Takamasa , Kondo Eitaro , Ota Arihito , Ito Toshihiro , Endoh Koki , Asahina Akihiko
Published: October 2023

Atopic dermatitis itch may cause sleep disturbance and impair quality of life. For patients finding topical therapy difficult to continue, it is important to control itch and reduce scratching. This study developed algorithms to measure nocturnal sleep and scratch, using an actigraph device worn on the back of the hand, and assessed smartphone application feedback to improve adherence with therapy. In the first trial, actigraph measurements in 5 participants who wore the device were highly correlated with measurements by a sleep-monitoring device beneath the mattress. Total actigraph-measured scratching duration for each hour of sleep was highly correlated with measurements by a person rating infrared video-recording of the sleepers. In the second trial, 40 patients with atopic dermatitis were randomly allocated into an intervention group that used the actigraph and smartphone application, and a control group that did not. Both groups were instructed to use the same moisturizer. Dermatology Life Quality Index scores decreased significantly from baseline and were lower than those in the control group at week 8. It is suggested that the device and associated smartphone application reinforced therapy adherence, moisturizer use, and contributed to improved quality of life in patients with atopic dermatitis.
Covid19-fertőzés repülésbiztonsági aspektusai 2. rész
Authors: Guth-Orji Ágnes
Published: October 2023

A Covid19-pandémia jelentős hatással volt életünk minden területére, a légi közlekedésre is, bár a Covid19 repülésbiztonsági aspektusait eddig kevesen vizsgálták. A Covid19 leggyakoribb szövődményei közül számos tünet jelentősen befolyásolja az emberi munkavégző képességet, fokozhatja a humán faktor hibaforrásveszélyét, így repülésbiztonsági kockázatot jelenthet. Jelen tanulmány célja a Covid19 megbetegedés lehetséges hatásainak azonosítása a repülésben részt vevő személyekre, azok repülésbiztonsági kockázatának felmérése és csökkentése, különös tekintettel a krónikus fáradtságra, amelynek objektív mérésére még kevés módszer létezik. A szerző a poszt-Covid okozta fáradtság hatását vizsgálta a fizikai erőnlétre, két hónappal a fertőzés után.
német alárendeltségbe léptetett magyar királyi I. gyorshadtest tevékenysége 3. rész
Authors: Somkutas Róbert
Published: October 2023

A Magyar Királyi Honvédség részvétele az 1941. évi Szovjetunió elleni hadműveletben a német Barbarossa hadművelet részét képezte. Az ott harcba vetett, német alárendeltségbe került magyar királyi I. gyorshadtest szervezetében két (páncélozott) felderítő-zászlóalj tevékenykedett. A csapatok tevékenységét az üldözés, illetve a több száz kilométeren keresztül történő, dinamikus tempójú Kelet felé nyomulás jellemezte. A sorozat első része az 1941. június 22. és július 9. közötti eseményeket idézi fel.
História como um agente cognitivo de aprendizagem matemática compreensiva
Authors: Mendes Iran Abreu
Published: October 2023

Este artigo ensaístico tem como objetivo discutir a importância da investigação histórica da matemática como um agente de cognição na aprendizagem compreensiva da matemática escolar. Inicialmente, faço conjecturas sobre a criatividade como uma habilidade humana de acordo com sua dinâmica cognitiva nos atos de conhecer, compreender e explicar. Ao longo do ensaio, discuto e reflito sobre princípios que sustentam o uso de práticas investigativas históricas no ensino de matemática, considerando que os professores precisam se apropriar de fatos matemáticos históricos para promover agenciamentos que proporcionem reorganizações conceituais em torno dos objetos matemáticos que os alunos irão construir durante sua vida escolar. Estes são princípios investigativos, problematizadores e fundamentadores do ensino e da aprendizagem matemática, que tomam os fatos matemáticos históricos como agentes cognitivos no ensino de matemática e como acionadores da aprendizagem dos estudantes. Por fim, menciono temas que podem ser agentes do ensino e da aprendizagem matemática, evocadores de funções conceituais e pedagógicas para se ensinar matemática a partir de métodos matemáticos históricos.
Contribuições da teoria da objetivação para a análise do planejamento de tarefas de um professor de matemática envolvendo alunos com transtorno do espectro autista
Authors: Takinaga Sofia Seixas , Manrique Ana Lucia
Published: October 2023

O presente artigo tem por objetivo compreender aspectos do planejamento do professor que potencializam a possibilidade do encontro do aluno com Transtorno do Espectro Autista (TEA) com o saber matemático. Trata-se de uma pesquisa de cunho qualitativo, tendo a entrevista semiestruturada e o planejamento de tarefas documentado por um professor como principais instrumentos de coleta de dados. A partir da análise do planejamento do professor, sujeito da pesquisa, discute-se a contribuição do referencial teórico, a Teoria da Objetivação, idealizada por Luis Radford, que fornece fundamentos que norteiam o componente delineamento da tarefa, o qual se traduz como o projeto didático do professor. São três as categorias: considerações gerais, considerações sobre os problemas matemáticos e considerações sobre as formas de colaboração humana. Como conclusão, as categoriais de análise emergentes dos elementos do componente delineamento da tarefa  permitiram identificar aspectos do planejamento do professor que potencializam  a possibilidade do encontro do aluno com TEA com o saber matemático, tais como: considerar conhecimentos prévios que emergem de situações vivenciadas em seu cotidiano; explorar contextos que permitam o encontro do aluno com o saber matemático de forma utilitarista; e explorar diferentes ambientes físicos, propiciando a convivência com regras e comportamentos adequados e a generalização de saberes escolares.
Sobre a Formação de Professores e Pesquisadores em Educação Matemática: pontos para uma Agenda
Authors: Marafioti Garnica Antonio Vicente
Published: October 2023

Registro integral da conferência de abertura do IX CIBEM (Congresso IberoAmericano de Educação Matemática), este artigo propõe três discussões para a integrar uma Agenda para a Educação Matemática, a saber: (a) a necessidade de redimensionar e ampliar objetos, enfoques, estratégias e abordagens metodológicas para o estudo acerca da formação de professores que ensinam Matemática; (b) a necessidade de dar maior atenção à perspectiva historiográfica, valorizando os estudos em História da Educação Matemática e incluindo essa perspectiva nas políticas educacionais; e (c) a possibilidade de incorporar a divulgação científica e projetos de popularização da Ciência entre os interesses do campo e, mais especificamente, nos Mestrados Profissionais que, com isso, teriam a oportunidade de reconfigurar e/ou cuidar com mais clareza de seus objetivos e intenções.
currículo e a formação do professor
Authors: Vieira André Ricardo Lucas , Silva Fabrício Oliveira da , Dias Alfrancio Ferreira
Published: October 2023

Este artigo tem como objetivo compreender como as vivências e aprendizagens experienciais da docência em matemática emergem narrativamente das práticas curriculares no ensino de matemática no IFSertãoPE. O estudo é de natureza qualitativa por acreditar que o sujeito e a realidade formativa são concebidos como indissociáveis e foi elaborado na abordagem da pesquisa narrativa, caracterizada por se tratar de um processo compreensivo/interpretativo das narrativas/experiências de quatro colaboradores que atuam como professores de matemática do Ensino Médio no Instituto Federal de Educação, Ciência e Tecnologia do Sertão Pernambucano. O dispositivo de pesquisa foi o ateliê reflexivo, desenvolvido em seis sessões. Os resultados permitem concluir que a formação inicial é fundante para a construção de um currículo que se efetive na relação de ações educativas. O estudo evidenciou como as aprendizagens experienciais da docência em matemática tecem-se nas microrrelações formativas que os professores desenvolvem por habitar a profissão docente no cotidiano escolar, produzindo saberes e experiências do vivido.
Escrita reflexiva no vaivém
Authors: Silva Gabriel dos Santos e , Gardin Francielle Silva
Published: October 2023

Neste artigo, tem-se por objetivo investigar indícios de escrita reflexiva nas produções escritas de futuras professoras de uma turma de Licenciatura em Matemática, do Instituto Federal do Paraná, campus Capanema em Vaivéns. Para tanto, utilizou-se um instrumento para Avaliação da Aprendizagem Escolar denominado Vaivém – que, em síntese, oportuniza a comunicação escrita entre professor e estudantes. Foram analisados excertos dos Vaivéns produzidos por cinco discentes do curso de Licenciatura em Matemática de um campus do Instituto Federal do Paraná, em um contexto de uma disciplina de estágio supervisionado realizada no primeiro semestre letivo de 2022. Por meio deste trabalho, foi possível identificar que o Vaivém oportuniza a manifestação de escritas reflexivas e, desse modo, destacaram-se ainda algumas características presentes nas reflexões manifestadas, tais como: desabafo/expressão de sentimentos, expectativas profissionais, pensamento sobre a prática docente, repensar e visão de mundo. Ressalta-se o papel das intervenções realizadas, que promoveram diálogos individualizados, proporcionando que as futuras professoras refletissem sobre aspectos de suas vidas pessoais e profissionais.
Propriedades comutativa e distributiva na proposição davydoviana para o ensino de Matemática
Authors: Euzébio da Rosa Joséia , Suethe Faust Hobold Ediséia
Published: October 2023

A investigação, de natureza bibliográfica, foi desenvolvida no contexto da educação matemática, especificamente sobre a organização do ensino das propriedades comutativa e distributiva em relação à multiplicação, proposto por Davýdov e colaboradores. Doutor em Psicologia e seguidor de Vigotski, Davýdov coordenou o processo de elaboração de uma proposta para o ensino de matemática fundamentada na Teoria Histórico-Cultural. A proposta pedagógica foi publicada, na Rússia, por meio de livros didáticos e manuais de orientação ao professor. O objetivo é analisar o modo de organização do ensino de matemática proposto por Davýdov e colaboradores na especificidade das propriedades comutativa e distributiva da multiplicação. A análise possibilitou revelar que essas propriedades são essenciais para a constituição do sistema conceitual da tabuada, o que implica a reorganização do seu ensino, cujo ponto de partida seja a relação entre grandezas discretas e contínuas na inter-relação da aritmética, álgebra e geometria.
Educação multisseriada do campo de São Caetano-Pernambuco
Authors: Silva Maria Jacqueline da , Cavalcanti José Dilson Beserra , Rodrigues Rochelande Felipe
Published: October 2023

O presente artigo faz parte de uma dissertação, no formato multipaper, desenvolvida no âmbito do Programa de Pós-Graduação em Educação em Ciências e Matemática da Universidade Federal de Pernambuco (UFPE), Centro Acadêmico do Agreste. Nosso objetivo foi analisar o organizador curricular de Matemática do currículo de referência para o ensino dessa disciplina nos anos iniciais, no contexto da Educação Multisseriada do Campo da rede municipal de São Caetano-PE. Para alcançarmos esse objetivo, adotamos na metodologia a abordagem qualitativa de caráter documental e analisamos dados coletados no Currículo de Pernambuco e em outras fontes. Dentre os resultados obtidos nessa investigação, constatamos que o organizador do currículo de Matemática do currículo de referência é genérico e limitado quando se trata da inclusão de saberes matemáticos, não constando saberes do contexto escolar específico nem de outras culturas
Promovendo o conhecimento especializado de futuros professores de Matemática sobre o algoritmo da divisão euclidiana
Authors: Almeida Marieli Vanessa Rediske de , Lopes Rian
Published: October 2023

Neste artigo, relatamos a experiência de um formador de professores, que é matemático, ao ensinar o Teorema do Algoritmo da Divisão Euclidiana em uma disciplina de Teoria dos Números para futuros professores de Matemática. Considerando que o conhecimento do professor que ensina Matemática é especializado, do ponto de vista do modelo Mathematics Teachers’ Specialised Knowledge, pretendemos identificar quais conhecimentos são mobilizados pelo formador e evidenciados pelos licenciandos quando o formador aborda esse resultado algébrico. Algumas atividades foram conduzidas pelo docente na tentativa de compreender como os licenciandos realizavam a divisão de números inteiros antes, durante e após conhecer o teorema; nossa análise foca esses diferentes momentos. Nos licenciandos, foi possível observar prioritariamente conhecimentos relacionados a procedimentos envolvendo o algoritmo. Não obstante, ao longo das atividades realizadas, eles foram capazes de estabelecer diferentes conexões envolvendo o algoritmo da divisão euclidiana. Com relação ao formador, destacamos que seu conhecimento matemático e pedagógico, aliado ao objetivo de efetivamente formar futuros professores de Matemática, tem o potencial para promover nos licenciandos um conhecimento especializado sobre o assunto.
Risco sistemático de longevidade em planos previdenciários
Authors: Cardoso Mainara de Paula Simões , Rocha Alane Siqueira
Published: October 2023

O risco de longevidade está presente na estrutura do sistema previdenciário brasileiro e pode ser definido como a probabilidade de os participantes de planos de previdência sobreviverem além do esperado. O objetivo geral deste trabalho é mensurar o impacto do risco de longevidade na solvência de planos de previdência com pagamento de benefícios vitalícios. Foi desenvolvido um modelo na linguagem Python que utilizou o processo de Simulação de Monte Carlo para desvendar as distribuições de probabilidades das provisões matemáticas para amostras com diferentes tamanhos. A partir da análise dos resultados, concluiu-se que o coeficiente de variação e a taxa de carregamento de contingência diminuem, tendendo a zero, à medida que o tamanho da população aumenta. Entretanto, a inclusão do risco sistemático de longevidade gera um cenário distinto, no qual a redução do carregamento de contingência atinge um limiar, ocasionando, portanto, reduções mínimas entre grupos de 5.000 a 50.000 segurados.
Grid-characteristic method using superimposed grids in the problem of seismic exploration of fractured geological media
Authors: Mitkovets I. A. , Khokhlov N. I.
Published: October 2023

Introduction.

Seismic exploration in conditions of heterogeneity of the environment is an urgent topic for the oil and gas industry. Consequently, the development of numerical methods for solving the direct problem of seismic exploration remains relevant as a necessary link in the development and improvement of methods for solving the inverse problem. The Schonberg thin crack model has performed well in the numerical solution of problems requiring explicit consideration of geological inhomogeneities.

Materials and Methods. In this paper, we consider a modification of the grid-characteristic method using superimposed grids. The presented approach makes it possible to conduct computational experiments, explicitly taking into account fractured inhomogeneities with arbitrary spatial orientation. For this, in addition to the basic regular computational grid, there is the concept of superimposed grids. Inhomogeneities, such as cracks, are described within the framework of the superimposed grid and, in turn, have no restrictions associated with the main grid. Thus, by performing an interpolation operation between the superimposed main grids, we can bypass the requirement of alignment of cracks and edges of the main grid.

Results. The proposed approach made it possible to study the dependence of the anisotropy of the seismic response of a fractured cluster on the dispersion of the angles of inclination of the cracks.

Discussion and Conclusions. A modification of the grid-characteristic method using superimposed grids is proposed to explicitly account for fractured inhomogeneities in a heterogeneous geological environment.
Keratuan Adat Menangsi Di Lampung Selatan
Authors: Mafilindo Herdius , Basri Muhammad , Arif Suparman
Published: October 2023

Tujuan penelitian ini untuk mengetahui sejarah Keratuan Adat Menangsi di Lampung Selatan. Metode yang digunakan adalah metode penelitian historis. Berdasarkan hasil penelitian berdirinya Keratuan Menangsi berawal dari runtuhnya Keratuan Balaw pada pertengahan abad XVI. Oleh karena keruntuhan ini, menurut beberapa catatan, bukti, dan peninggalan yang ada Keratuan “Ratu Menangsi” diperkirakan berdiri sekitar akhir abad ke- XVI kurang lebih pada tahun 1594 di wilayah Kalianda Lampung Selatanyang berpusat di Way Andak/ Batu Handak/ Candi Taman.
Kırsal Turizm Kapsamında Aromatik Turizm Potansiyelinin Değerlendirilmesi: Fethiye İncirköy Örneği
Authors: Çaprak Doğan , Yalçınkaya Akdemir Pınar , Çeken Hüseyin , Akıncı Burçak
Published: October 2023

Bu çalışmanın amacı, aromatik turizmin geliştirilmesi açısından zengin kırsal alanlara sahip Muğla’nın Fethiye ilçesinde yer alan İncirköy’ün aromatik turizm arz potansiyelinin değerlendirilmesidir. Bu bağlamda nitel araştırma yöntemi kapsamında görüşme tekniği kullanılmıştır. 2022 yılının Temmuz ve 2023 yılının Nisan aylarında toplam on üç katılımcı ile görüşme sonrası elde edilen veriler, betimsel analiz ile yorumlanarak değerlendirilmiştir. Araştırma sonucuna göre İncirköy’ün yeterli sayıdaki aromatik bitki tarlasına sahip olması, yöre halkının daha önce turizmde çalışmış olması, Fethiye’ye yakın olması, tur operatörleri için yeni turistik ürün oluşturması açısından aromatik turizm arz potansiyeline sahip olduğu görülmektedir.
Fluent in War and Peace
Authors: Hoade Robert
Published: October 2023

This research is an observation of the life and actions of the Lakota Sioux headman, Red Cloud. A consideration of his life provides the observer with an understanding of the Lakota epoch on the northern Great Plains of North America and his role in the continuation of the Lakota people. As Red Cloud ascended the Lakota meritocracy, he led multiple successful sorties against rival Native groups and the American military. These actions included horse raids and combat missions that enforced Lakota supremacy over the modern Dakotas, Northern Nebraska, eastern Montana, and Wyoming. Later in his life, he and other Plains Natives encountered increasing numbers of Euro-Americans in the form of civilian settlers and traders followed by elements of the Federal Government. As tensions built between the Plains Natives and the US, Red Cloud began to actively oppose American intrusions into Lakota land. The crescendo of Red Cloud’s physical resistance was the Fetterman Fight, an action in which Red Cloud and his allies encircled and destroyed a company-sized element of the US Army. Following its defeat, the US proposed peace through the 1868 Treaty of Fort Laramie. To the US, the agreement concentrated the Lakota in southern South Dakota, away from American economic activities. To men like Red Cloud, unfamiliar with concepts of finite containment, the treaty only affirmed their hunting rights and hegemony in the region. However, as waves of new migrants flowed west from their eastern metropoles, it became apparent to Red Cloud that the policy of the Federal Government was the permanent concentration and degradation of the Lakota. Faced with this forlorn reality, Red Cloud led the Lakota on the reservation through a restricted existence. Despite the Federal attempts at the degradation of the tribe, Red Cloud, using pacifist defiance, ensured the Lakota’s survival and the preservation of a large portion of the region he conquered in his youth. It is possible that his choice to surrender on terms favorable to his tribe and the timing of his cessation of combat actions were more important to the survival of the Lakota than the decision of his peers to continue their war with the US. This is evident in the continuation of the Lakota Pine Ridge Reservation based on the agreement between the US and the Lakota following Red Cloud’s victories in the Powder River Region. Although the Reservation was and is a form of human concentration and containment, it was, a relatively safe place for the Lakota when one considers their treatment outside the sphere of Red Cloud’s influence, most notably the massacre at Wounded Knee.
Predictors of Adverse Clinical Outcomes after Endovascular Thrombectomy in Acute Ischemic Stroke
Authors: Vildanov T. R. , Plechev V. V. , Zagidulina M. S. , Chudnovets L. G. , Kolchina E. M. , Karamova I. M. , Plecheva D. V. , Chudnovets G. L.
Published: October 2023

Introduction. Stroke is recognized as one of the most significant global socio-economic issues. Endovascular interventions, including mechanical thrombectomy of cerebral arteries, have been increasingly performed during the past decade to restore impaired cerebral blood flow in the first hours from the onset of the disease. However, it has been observed that the technical success of the procedure does not always imply an improvement in the clinical condition of a patient.Materials and methods. The study retrospectively analyzes the outcomes of interventions in 86 acute ischemic stroke patients in order to identify factors that can exert an adverse effect on the first hours of the disease and potentially worsen the results of reperfusion therapy. The study involves patients aged 35–85 years (mean age 66.82±1.52 years), predominantly males (57 males versus 29 females). 42 patients (49%) suffered atrial fibrillation, of which 28 (66.7%) had permanent, 11 (26.2%) — paroxysmal, 3 — persistent atrial fibrillation (7.1%), and 27 (31.4%) suffered diabetes mellitus.Results and discussion. Based on the study, factors affecting outcome and one-year long-term results were identified. The predictors included severity of neurological deficit according to Rankin and NIH Stroke scales, time between symptom onset and reperfusion, TICI thrombectomy score, age, diabetes mellitus, and haemorrhagic transformation after thrombectomy.Conclusion. In order to ensure better outcomes, medical specialists should develop an efficient patient routing, pay special attention to the initial severity of neurological deficit, time from the onset of the disease, age of patients, concomitant diabetes mellitus, development of hemorrhagic transformation after endovascular thrombectomy, and, which is particularly important, to the combination of adverse factors.
Staged Surgical Treatment for Patients with Liver Tumors and Optimal Method of Vicarious Hypertrophy of the Liver Remnant: Literature Review
Authors: Pelts V. A. , Tropin V. E. , Pavlenko V. V. , Krasnov A. O.
Published: October 2023

The evolution of hepatic surgery at the present stage of medical development requires specialists to develop patient-oriented rational surgical tactics and use modern methods for the diagnosis and prediction of post-resection liver failure in the surgical treatment of liver tumors by resection, thereby forming approaches that reduce the risks of severe postoperative complications associated with insufficient liver remnants remaining after extensive resection. The paper reviews the problematic issues of diagnosis and treatment of liver tumors, as well as provides current views on the relevance of timely prevention of post-resection liver failure. The study considers methods for assessing the risks of complications and adverse outcome when planning and performing extensive liver resections, defines the concept of post-resection liver failure, and highlights the main mechanisms of vicarious hypertrophy. The paper examines the most commonly used methods for vicarious hypertrophy of the parenchyma remaining after extensive liver resection, their advantages, and disadvantages. The main possible causes of failures in developing a strategy for two-stage liver resections are analyzed. A critical analysis of available contemporary literature enabled the authors of the paper to identify possible ways to further improve the results of extensive liver resections.
Producer Gas Composition Prediction using Artificial Neural Network Algorithm
Authors: Mohammud Mohd Mahadzir , Mohamad Bakre Muhammad Syaham , Mohd Fohimi Nor Azirah , Rabilah Rosniza , Ahmad Muhammad Iqbal
Published: October 2023

Nowadays, methods to increase efficiency in producer gas have become major issues in biomass gasification research. Producer gas is a renewable energy source that does not take as much time to obtain as fossil fuels. It is typically a mixture of combustible gases like carbon monoxide, hydrogen and methane, and non-combustible gases like carbon dioxide and nitrogen. A high percentage volume of combustible composition in the producer gas output will have a high calorific value or heat of combustion. These combustible gases are determined by the design of the gasifier. In today's era of Industrial Revolution 4.0 and Society 5.0, the use of simulation is highly prioritised in all aspects of engineering, especially in gasification applications. Simulation is a useful tool for learning about the governing principles and optimal operating points of the gasification process. Artificial intelligence (AI), is a major focus of Industry Revolution 4.0. In this project, the producer gas composition prediction is studied by computer simulation. The goals are to predict the output producer gas using an algorithm and to compare the trained prediction result with actual experiment data for rice husk gasification. This simulation was created with MATLAB software's artificial neural network (ANN). Three parameters (the height of the gasifier, the diameter of the gasifier, and the weight of the rice husk) are set as input data, and six types of the composition of producer gas (carbon dioxide, carbon monoxide, methane, oxygen, hydrogen, and nitrogen) are set as output data. The algorithm is trained, tested, and verified with the experiment data. It is then used to predict the output gas composition from the parameters of a gasification experiment that has been used before in UiTM’s laboratory. The simulation results of producer gas composition between prediction and actual values revealed a relative error of 1.159 %, 0.370 %, and 0.330 %. These results were less than 9% and were found to give a very good fit to the neural network algorithm.
Analysis of Flexible Silver-printed NFC Tag Antenna on Miniaturization and Bending Effect
Authors: Mohd Faudzi Najwa , Razali Ahmad Rashidy , Abdul Manaf Asrulnizam , Abd Rahman Nurul Huda , Aziz Ahmad Azlan , Ibrahim Amiruddin , Mozi Aiza Mahyuni
Published: October 2023

Size and flexibility are the two main elements that must be considered in designing a near-field communication (NFC) tag antenna because they will determine the performance of the whole system. The previously designed NFC tag antenna, which is made of a rigid substrate such as FR-4, limited the application of the tag to only on a flat surface. The size of the tag antenna also needs to be optimised based on the application requirements since different sizes of the antenna will contribute to different electrical properties, including inductance and resistance. Therefore, this paper presents an analysis of a flexible printed tag antenna with different miniaturisation sizes and bending effects for NFC systems. The operating frequency of the proposed NFC tag antenna is 13.56 MHz, which is the same frequency as the NFC reader, allowing them to be coupled and to communicate with each other. Three sizes of silver printed tag antenna are presented, and the performance of the tag during bending is analyzed. Other tag antenna parameters and characteristics, including reflection coefficient, inductance, resistance, read range and output voltage, are also observed through simulation and accordingly measured. The results show that the Design 1 antenna has demonstrated the highest measured tag reading range of 3 cm, while the Design 2 antenna has shown good flexibility, withstanding bending at various angles and exhibiting a minimum reading range of 0.5 cm. Overall, the correlation between antenna size, flexibility and antenna performance has been determined and systematically validated.
Formulation and Evaluation of Gastroretentive In Situ Gelling System of Ketoprofen
Authors: Shabaraya AR. , T Ashwini T. , Vineetha K.
Published: October 2023

A revolutionary concept for achieving long-term medication release is the gastroretentive in situ gelling system. The goal of this research was to formulate and test a gastroretentive in situ gel for ketoprofen delivery to targeted site to increase the residence and delivery time. Ketoprofen gastroretentive in situ gels were synthesized using a cation-driven gelation approach using various combinations and concentrations of polymers such as gellan gum, sodium alginate, and hydroxypropyl methylcellulose (HPMC) K100M. Visual appearance, pH, viscosity, in vitro gelation, in vitro buoyancy, drug content, density measurement, gel strength measurement, water uptake, and in vitro drug release were all evaluated. The total floating time was more than 12 h, with a floating lag time of less than 2 min. The formulations showed pH ranging from 6.89 to 7.61 and drug content ranging from 82.01% to 95.53%. For 11 h, the percent cumulative drug release of formulations F5 and F14, which contained a greater concentration of polymer sodium alginate (1.5%) and a combination of gellan gum and HPMC K100M (0.175% and 0.2%), was 84.10% and 85.49%, respectively. In vitro dissolution experiments and stability investigations both revealed no significant changes in drug content. The findings revealed that the formulated in situ gels aided in extending gastric residence duration, allowing the drug to be released in the stomach.
Top management team diversity impact on financial performance: Evidence from VW Group affiliated firms
Authors: Velinov Emil
Published: October 2023

Diversity within top management teams (TMTs) has significant implications for firm financial performance, particularly in dynamic industries like the automotive sector. This paper analyzes the relationship between TMT diversity and financial outcomes in companies associated with the Volkswagen Group, operating in an intensely competitive market marked by technological advancements. This comprehensive paper synthesizes studies investigating the correlation between TMT diversity and financial performance within the automotive domain. Employing quantitative approaches, these studies assess demographic factors such as gender, age, ethnicity, and educational background. The analysis unveils distinct patterns of impact. Gender diversity within TMTs exhibits a positive influence on financial performance, with heightened profitability and increased market value being notable outcomes. Age diversity shows a nuanced trend, with moderate levels enhancing strategic decision-making capabilities and fostering innovation. Increased ethnic diversity within TMTs is associated with elevated innovation and overall firm performance. Furthermore, educational diversity within TMTs is found to bolster firm performance, underscoring its pivotal role in strategic decision-making and innovation. By offering a comprehensive synthesis of TMT diversity’s connection to financial performance within the Volkswagen Group’s context, this paper contributes novel perspectives. The study emphasizes the methodologies utilized, outlines key findings, and underscores the original contributions made by existing research. This study illuminates the profound influence of TMT diversity on shaping strategic decisions and fostering innovation in the automotive sector. Importantly, it highlights the crucial role of TMT diversity in driving positive financial outcomes.