bluuebunny/crossref_metadata_2025 huggingface dataset:
The Sino-Venezuelan Relationship (1974-2020)
Authors: Reyes Vázquez Ángel
Published: July 2021

The Sino-Venezuelan relationship can be divided into three distinct eras: the origin of the relationship (1974-1999), the golden age during Chávez presidency (1999-2013) and a declining relationship after Maduro rise to power (2014-onwards).

This paper aims to provide a historic, political, and economic overview of the bilateral relationship between 1974 and early 2020, in order to determine if the China-Venezuela link is truly based on pragmatism. Additionally, it will identify the problems the bilateral relationship has faced since 2014, as well as the factors which determine President Xi’s current support of Maduro.
China’s Foreign Policy towards Eurasia Economic Integration
Authors: Yingying Fu
Published: July 2021

During the period from 2005 to 2015 under the rule of Hu Jintao and Xi Jinping, China has achieved enormous success not only in the field of economy but also in the political and diplomatic areas. With the Silk Road Economic Belt’s initiative launched by the government of Xi in 2013, China was seeking to find alternatives for different affairs such as the South China Sea, the nuclear issue of North Korea, and Taiwan issues. The emergency of the “Strategic Breakthrough” whose aim is to stabilize the surrounding atmosphere makes it a pressing task for the Chinese diplomacy focused on Eurasia to overhaul the international order.
Первая краевая задача в прямоугольной области для дифференциального уравнения с оператором Бесселя и частной производной Римана-Лиувилля
Authors: Хуштова Фатима Гидовна , Khushtova Fatima Gidovna
Published: July 2021

Для дифференциального уравнения с сингулярным оператором Бесселя, действующим по пространственной переменной, и оператором дробного дифференцирования Римана-Лиувилля, действующим по временной переменной, рассматривается краевая задача в прямоугольной области с граничными условиями первого рода. Построено явное представление решения. Единственность решения доказана в классе функций, удовлетворяющих условию Гeльдера по временной переменной. Когда порядок дробной производной равен единице, а особенность у оператора Бесселя отсутствует, рассматриваемое уравнение совпадает с уравнением теплопроводности и полученные результаты совпадают с известными соответствующими классическими результатами.
Уточненная модель вязкоупругопластического деформирования гибких пространственно-армированных цилиндрических оболочек
Authors: Янковский Андрей Петрович , Yankovskii Andrei Petrovich
Published: July 2021

Разработана модель вязкоупругопластического деформирования гибких круговых цилиндрических оболочек с пространственными структурами армирования. Мгновенное пластическое поведение материалов композиции определяется теорией течения с изотропным упрочнением.
Вязкоупругое деформирование компонентов композиции описывается уравнениями модели тела Максвелла-Больцмана. Геометрическая нелинейность задачи учитывается в приближении Кармана.
Используемые соотношения позволяют с разной степенью точности рассчитывать остаточные перемещения точек конструкции и остаточное деформированное состояние компонентов композиции. При этом моделируется возможное слабое сопротивление армированной оболочки поперечному сдвигу.
В первом приближении используемые уравнения, начальные и граничные условия редуцируются в соотношения неклассической теории Амбарцумяна.
Численное решение сформулированной начально-краевой задачи строится по явной схеме «крест».
Исследовано упругопластическое и вязкоупругопластическое динамическое деформирование тонких стеклопластиковых оболочек под действием внутреннего давления взрывного типа. Рассматриваются две структуры армирования:
1) ортогональное армирование в продольном и окружном направлениях;
2) пространственное армирование в четырех направлениях.
Показано, что даже для относительно тонких композитных оболочек теория Амбарцумяна неприемлема для получения адекватных результатов расчетов их вязкоупругопластического динамического деформирования. Продемонстрировано, что расчет по теории упругопластического деформирования армированных конструкций не позволяет даже приближенно оценить остаточные состояния композитных оболочек после их динамического нагружения. Показано, что даже для относительно тонкой и длинной цилиндрической оболочки замена традиционной «плоско»-перекрестной структуры армирования на пространственную структуру позволяет существенно уменьшить интенсивность остаточных деформаций связующего материала. В случаях относительно толстых и, особенно, коротких оболочек положительный эффект от такой замены структур армирования проявляется в значительно большей степени.
Дифференциальная ошибка угла ориентации анеморумбометра горизонтально-осевой ветроэнергетической установки
Authors: Соломин Евгений Викторович , Solomin Evgenii Viktorovich , Терехин Александр Александрович , Terekhin Alexandr , Мартьянов Андрей Сергеевич , Martyanov Andrey Sergeevich , Ковалeв Антон Александрович , Kovalyov Anton Alexandrovich , Исмагилов Денис Рашидович , Ismagilov Denis , Мирошниченко Алексей Александрович , Miroshnichenko Alexey , Ян Юйсун , Yang Yusong , Рявкин Глеб Николаевич , Ryavkin Gleb
Published: July 2021

Рассматривается проблема ориентации горизонтально-осевых ветроэнергетических установок при изменении направления, силы и скорости ветра.
Когда направление ветра меняется, активная ометаемая площадь ротора, представляющая собой круг при коллинеарности оси вращения и вектора набегающего потока, уменьшается и принимает форму эллипса. Это, в свою очередь, приводит к снижению вырабатываемой электроэнергии.
Для ориентации ротора используется анеморумбометр, регистрирующий скорость и направление потока ветра. При изменении направления потока ветра соответствующий сигнал передается системе управления, которая дает команду на разворот ротора на ветер.
Однако при прохождении потока ветра между вращающимися лопастями его направление искажается, происходит вихреобразование, в результате чего прибор выдает изначально неверные данные о направлении и скорости потока. В результате при регулировании положения ротора коллинеарность оси вращения и вектора набегающего потока не достигается, ометаемая площадь постоянно остается эллипсообразной, а вырабатываемая мощность пропорционально снижается. В связи со значимостью приведенной проблемы целью исследования является получение численных значений угла отклонения в различных режимах путем трехмерного моделирования в программном комплексе
ANSYS CFX. Полученные сведения могут быть использованы в дальнейшем для разработки алгоритма устранения данной ошибки.
Exact boundaries for the analytical approximate solution of a class of first-order nonlinear differential equations in the real domain
Authors: Orlov Victor Nikolaevich , Kovalchuk Oleg Aleksandrovich
Published: July 2021

Дано решение одной из задач аналитического приближенного метода для одного класса нелинейных дифференциальных уравнений первого порядка с подвижными особыми точками в вещественной области. Рассматриваемое уравнение в общем случае не разрешимо в квадратурах и имеет подвижные особые точки алгебраического типа. Это обстоятельство требует решение ряда математических задач. Ранее авторами была решена задача влияния возмущения подвижной особой точки на аналитическое приближенное решение. Это решение основывалось на классическом подходе и, при этом, существенно уменьшилась область применения аналитического приближенного решения, по сравнению с областью, полученной в доказанной теореме существования и единственности решения. Поэтому в статье предлагается новая технология исследования, основанная на элементах дифференциального исчисления. Этот подход позволяет получить точные границы для аналитического приближенного решения в окрестности подвижной особой точки. Получены новые априорные оценки для аналитического приближенного решения рассматриваемого класса уравнений, хорошо согласующиеся с известными для общей области действия. При этом, представленные результаты дополняют ранее полученные, существенно расширена область применения аналитического приближенного решения в окрестности подвижной особой точки. Приведенные расчеты согласуются с теоретическими положениями, о чем свидетельствуют эксперименты, проведенные с нелинейным дифференциальным уравнением, обладающим точным решением. Дана технология оптимизации априорных оценок погрешности с помощью апостериорных оценок. В исследованиях применялись ряды с дробными отрицательными степенями.
Quantum evolution in terms of mechanical motion
Authors: Samarin Alexey Yur'evich
Published: July 2021

Туннельный эффект рассматривается с точки зрения локального реализма. Сделан вывод о том, что квантовый объект, туннелирующий через потенциальный барьер, нельзя интерпретировать как материальную точку, потому что такая интерпретация противоречит невозможности движения быстрее скорости света в вакууме. Такого противоречия не возникает, если квантовый объект рассматривать как сплошную среду, образованную материальными полями. Показано, что закон динамики механического движения этих полей материи может быть выведен из закона квантовой эволюции в форме интеграла по траекториям. Анализ процесса туннелирования показывает, что этот закон динамики имеет форму принципа наименьшего действия с комплексной временной переменной. Используемый здесь подход позволяет не только придать физическую интерпретацию туннельному эффекту, согласующуюся со специальной теорией относительности, но также описать широкий круг квантовых явлений, для которых традиционные методы исследования неосуществимы.
Unveiling Roland Oliveira’s photographic images: development of an unrolling and flattening treatment for silver gelatine 35 mm negative films
Authors: Silva Joana , Garrucho Sandra , Carvalho Filipa
Published: July 2021

The photographic collection by the sports photographer Roland Oliveira (1920-2007), belonging to Sport Lisboa e Benfica, is comprised of an estimate of 40000 images captured in 35 mm silver gelatine negative film, which are currently rolled and stiffened.

This study has strived to survey the current procedures undertaken by Portuguese institutions concerning the conservation of these type of materials, by conducting a questionnaire. It became evident that new treatments to allow the flattening of rolled films were needed. Therefore, a conservation treatment was developed to unroll and restore the original flatness of the negatives under study. The main purpose of the treatment was to enable proper handling, digitization and storage of this collection. The developed procedure was based on a de-shrinking process (chamber with vapours of glycerol, acetone and water) adapted from the conservation of motion-picture film literature, combined with flattening under weights. This paper discusses the adopted methodology which allowed to achieve positive results.
Identification of a new mutation in the human xanthine dehydrogenase responsible for xanthinuria type I
Authors: Collazo Abal Cristina , Romero Santos Susana , González Mao Carmen , Pazos Lago Emilio C. , Barros Angueira Francisco , Castiñeiras Ramos Daisy
Published: July 2021

Objectives

Hereditary xanthinuria is a rare, autosomal and recessive disorder characterized by severe hypouricemia and increased xanthine excretion, caused by a deficiency of xanthine dehydrogenase/oxidase (XDH/XO, EC: 1.17.1.4/1.17.3.2) in type I, or by a deficiency of XDH/XO and aldehyde oxidase (AOX, EC: 1.2.3.1) in type II.

Methods

We describe a novel point mutation in the XDH gene in homozygosis found in a patient with very low serum and urine levels of uric acid, together with xanthinuria. He was asymptomatic but renal calculi were discovered during imaging.

Results

Additional cases were found in his family and dietary recommendations were made in order to prevent further complications.

Conclusions

Hereditary xanthinuria is an underdiagnosed pathology, often found in a routine analysis that shows hypouricemia. It is important for Laboratory Medicine to acknowledge how to guide clinicians in the diagnosis.
Unconditional Basic Income and State as an Employer of Last Resort: A Reply to Alan Thomas
Authors: Merrill Roberto , Neves Catarina
Published: July 2021

In a larger context of an egalitarian project which aims to reformulate capitalism a job guarantee program in the form of a State as an Employer of Last Resort (SELR) is considered superior to Unconditional Basic Income (UBI) by many, namely Alan Thomas. This article claims that most of the arguments used to assert the superiority of SELR fail their objective, for the following reasons: first, SELR falls short in its reformulation of capitalism because neither SELR nor UBI alone can euthanize the rentier class. Second, most accounts are based on a flawed assumption that UBI leads to rampage inflation. Third, if macroeconomic considerations are not enough to justify implementing SELR over UBI, then insisting on the superiority of SELR can only stem from two types of moral reasons: on one hand from a perfectionist view of empowering the worst-off through labor and on the other from demands and obligations of reciprocity. We argue that these two moral-based reasons fall short of providing a justification for the superiority of SELR over UBI. We conclude our paper defending the possibility of conciliating the two policies.
Molecularly imprinted electrospun fiber membrane for colorimetric detection of hexanoic acid
Authors: Ying Xiaoguang , He Jieyuan , Li Xiao
Published: July 2021

An imprinted electrospun fiber membrane was developed for the detection of volatile organic acids, which are key components of human body odor. In this study, hexanoic acid (HA) was selected as the target, polymethyl methacrylate (PMMA) was used as the substrate, and colorimetric detection of HA was achieved by a bromocresol purple (BCP) chromogenic agent. The results showed that the morphology of the fiber membrane was uniform and continuous, and it showed excellent selectivity and specificity to HA. Photographs of the color changes before and after fiber membrane adsorption were recorded by a camera and quantified by ImageJ software by the difference in gray value (ΔGray). This method is simple, intuitive, and low cost and has great potential for application in human odor analysis.
The effect of raw dehydrated potato flour on the rheological properties of dough and nutritional quality of chiffon cakes
Authors: Zhao Yuci , Zhou Xiaoping , Lei Chunni , Shang Yan , Xu Dan , Liu Gang
Published: July 2021

In this study, chiffon cakes were fortified with potato flakes and raw dehydrated potato flour (RDPF) prepared by freeze-drying and hot air drying. The dough’s rheological properties demonstrate that potato flakes are unsuitable for making chiffon cakes, especially at percentages of 30 and 50%. Adding RDPFs decreased the dough height and adhesiveness but increased the hardness slightly compared with the control. Supplementing with potato flakes has the most influence on cake textural properties, especially at percentages of 30 and 50%, which correspondingly reduces the sensory evaluation score. All the RDPF cake formulations exhibited higher comprehensive nutritional value in terms of protein, fat, dietary fiber, minerals, and amino acids. The cake formulations containing RDPF obtained by hot air drying contained the lowest carbohydrate contents.
Redetermination of the crystal structure of (2E,4Z,13E,15Z)-3,5,14,16-tetramethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosa-1(22),2,4,7,9,11,13,15,18,20-decaene, C22H24N4
Authors: Dey Lucky , Rabi Saswata , Begum Zinnat A. , Takase Tsugiko , Rahman Ismail M. M. , Tiekink Edward R. T. , Roy Tapashi Ghosh
Published: July 2021

C22H24N4, triclinic,

P

1
‾

$P‾{1}$

(no. 2), a = 9.217(4) Å, b = 9.774(4) Å, c = 10.843(4) Å, α = 96.770(2)°, β = 101.791(5)°, γ = 105.873(3)°, V = 903.9(6) Å3, Z = 2, R

gt
(F) = 0.0391, wR

ref
(F
2) = 0.1069, T = 93(2) K.
Snow samples from settlements of the Murmansk region-genotoxic effects in Drosophila germ cells
Authors: Nikitina Tatyana A. , Smirnova Maria V. , Ingiri Andrey A. , Sandimirov Sergey S. , Elizarova Irina R. , Kudryavtseva Liubov P. , Petrashova Dina A. , Yurtseva Nadezhda A.
Published: July 2021

The Drosophila melanogaster organism is highly sensitive Biotester to mutagens or mutagenic carcinogens and can reveal mutations in both somatic and germ cells. The results of assessing the genotoxicity of snow samples from different inhabiled localities of Murmansk region – a region of with increased anthropogenic load – are shown in the article. In addition to the detection of genotoxic effects in different settlements, a highly significant correlation with the content of a number of metal ions in the samples, which makes the obtained results especially relevant.
Modeling and dynamic characteristics of the dense phase region of a biomass-fired circulating fluidized bed combustion system using Modelica
Authors: Liu Ya-Ya , Pan Lei , Liu Shan-Jian , Li Yong-Jun , Liu Wei-Dong , Wang Shuai-Chao
Published: July 2021

Using Modelica language, a mathematical model combining static and dynamic contributions of the dense phase region of a 130 t/h biomass circulating fluidized bed boiler combustion system was established on MWorks simulation platform. The mathematical model adopted modular packaging to increase the universality of the model, and it used an implicit, high-order, and multi-step Dassl integration algorithm to conduct the simulation. Under the design condition parameters, the relative error between the bed temperature of the dense phase region obtained by the simulation model and the actual temperature was less than 3.8%, which indicated that the static characteristics of the established simulation model were accurate. The effects of biomass feed and primary air volume step changes on the bed temperature, oxygen content in the flue gas, height of the dense phase region, and the bed pressure difference in the dense phase region were investigated. Both the biomass feeding and the primary wind step of 10% reduced the temperature, and it was obvious that the primary wind had a greater impact on the bed temperature. Meanwhile, the primary wind had a greater impact on the bed pressure difference than the biomass feeding.
Attribution in the Statistics Mirror Anonymous Articles in the “Vremya” and “Epokha” Journals Published by the Dostoevsky Brothers’
Authors: Zakharova Olga
Published: July 2021

The attribution of content of Vremya (Time) and Epokha (Epoch) journals, in which many anonymous and pseudonymous articles have been published, presents many challenges for the researchers. In the XIX–XX centuries, a corpus of texts, which were unambiguously attributed to F. M. Dostoevsky, M. M. Dostoevsky, A. A. Grigoriev, N. N. Strakhov and other Vremya and Epokha authors, was formed on the basis of traditional documentary (letters, payroll, income and expense book, memoirs), ideological and thematic and stylistic evidence. The following types of texts were isolated within the corpus of anonymous and pseudonymous articles, author's and collective articles, editorial inserts, notes; by type of writing - authorship, co-authorship, editing and adaptation of others texts. Modern methods of statistical analysis of formal grammatical and syntactic parameters in the text can provide sufficient grounds for expanding the source attribution base. This article presents the results of a study of a number of anonymous articles in the Dostoevsky brothers' journals using three statistical methods of attribution: linguistic and statistical analysis according to the G. Kjetsaa's method, the Transformer neural network and the Random forest algorithm. These results need to be correlated; they should be taken into account as complementary to traditional attribution methods.
On the homology groups $H_k(\mathbb{C}\Omega_n)$, $k=1, ..., n$
Authors: Pasko A.M.
Published: July 2021

In the paper the homology groups of the $(2n+1)$-dimensional CW-complex $\mathbb{C}\Omega_n$ are investigated. The spaces $\mathbb{C}\Omega_n$ consist of complex-valued functions and generalize the widely known in the approximation theory spaces $\Omega_n$. The research of the homotopy properties of the spaces $\Omega_n$ has been started by V.I. Ruban who in 1985 found the n-dimensional homology group of the space $\Omega_n$ and in 1999 found all the cohomology groups of this space. The spaces $\mathbb{C}\Omega_n$ have been introduced by A.M. Pasko who in 2015 has built the structure of CW-complex on these spaces. This CW-structure is analogue of the CW-structure of the space $\Omega_n$ introduced by V.I. Ruban. In present paper in order to investigate the homology groups of the spaces $\mathbb{C}\Omega_n$ we calculate the relative homology groups $H_k(\mathbb{C}\Omega_n, \mathbb{C}\Omega_{n-1})$, it turned out that the groups $H_k \left (\mathbb{C}\Omega_n, \mathbb{C}\Omega_{n-1}  \right )$ are trivial if  $1\leq k < n$ and $H_k \left (\mathbb{C}\Omega_n, \mathbb{C}\Omega_{n-1}  \right )=\mathbb{Z}^{C^{k-n}_{n+1}}$  if $n \leq k \leq 2n+1$, in particular $H_n \left (\mathbb{C}\Omega_n, \mathbb{C}\Omega_{n-1}  \right )=\mathbb{Z}$. Further we consider the exact homology sequence of the pair $\left (\mathbb{C}\Omega_{n+1}, \mathbb{C}\Omega_n   \right )$ and prove that its inclusion operator $i_*: H_k(\mathbb{C}\Omega_n) \rightarrow H_k(\mathbb{C}\Omega_{n+1})$ is zero. Taking into account that the relative homology groups $H_k \left (\mathbb{C}\Omega_{n+1}, \mathbb{C}\Omega_n  \right )$ are zero if $1\leq k \leq n$ and the inclusion operator $i_*=0$ we have derived from the exact homology sequence of the pair $\left (\mathbb{C}\Omega_{n+1}, \mathbb{C}\Omega_n   \right )$ that the homology groups $H_k \left ( \mathbb{C}\Omega_n \right ), 1\leq k<n,$ are trivial. The similar considerations made it possible to calculate the group $H_n(\mathbb{C}\Omega_n)$. So the homology groups $H_k(\mathbb{C}\Omega_n), n \geq 2, k=1,...,n,$ have been found.
Researches on summation problem in Dnipropetrovsk State University
Authors: Alkhimov M.I.
Published: July 2021

Researches on summation problem in Dnipropetrovsk State University.
Necessary conditions of extremality in one problem of approximation theory
Authors: Korneichuk N.P.
Published: July 2021

Necessary conditions of extremality in one problem of approximation theory.
On mean approximation of continuous periodic functions by functions that satisfy Lipschitz condition
Authors: Turovets S.P.
Published: July 2021

On mean approximation of continuous periodic functions by functions that satisfy Lipschitz condition.
On differential properties of one class of nonlinear singular integral operators
Authors: Chernyshenko D.N.
Published: July 2021

On differential properties of one class of nonlinear singular integral operators.
Research on some linear approximation processes
Authors: Yatsenko N.Ya.
Published: July 2021

Research on some linear approximation processes.
On convergence of trigonometric polynomials of the best mean-square approximation
Authors: Kostenko Ye.I.
Published: July 2021

On convergence of trigonometric polynomials of the best mean-square approximation.
On conditions of convergence of some double infinite products
Authors: Slepenchuk K.M.
Published: July 2021

On conditions of convergence of some double infinite products.
Estimate of error of cubature formula for the class of differentiable $2\pi$-periodic functions of two variables
Authors: Alkhimova V.M.
Published: July 2021

Estimate of error of cubature formula for the class of differentiable $2\pi$-periodic functions of two variables.
Uma prática de laboratório para equações diferenciais parciais: condução de calor em uma barra de cobre
Authors: Lacortt Marcelo , Pitol Boeira Alexandre , Cukla Anselmo Rafael
Published: July 2021

Considerando que aulas práticas tornam o processo de ensino e aprendizagem mais agradáveis e significativos, assim como, buscando propor aos alunos um melhor entendimento do assunto equações diferenciais parciais, neste trabalho, foi realizado um experimento envolvendo ensaios de laboratório e o uso de equações diferenciais. A pesquisa em questão aborda um problema de condução de calor, o qual foi desenvolvido em dois momentos, o primeiro foi um ensaio em laboratório no qual foi realizado o aquecimento de uma barra de cobre. Já a segunda análise do problema foi abordada analiticamente, pela modelagem matemática da função condução de calor, a qual foi obtida pela equação diferencial parcial que descreve o fluxo de calor em uma barra. Dessa forma, o trabalho, em específico, consiste no estudo térmico realizado em uma barra de cobre cujas extremidades foram isoladas, e, durante o ensaio, a barra foi inicialmente aquecida e posteriormente resfriada até a temperatura ambiente, comparando assim os resultados obtidos via experimentação prática com os resultados obtidos pela solução analítica, através da equação condução de calor. Para coleta de dados no laboratório, foram utilizados sensores de temperatura e, para obtenção dos resultados pela equação condução de calor, foi utilizado o software Maple. De posse dos dados, foram feitas análises dos resultados e do comportamento, com o auxílio de tabelas e gráficos. Os resultados obtidos foram satisfatórios, com semelhanças significantes entre ambos os experimentos, implicando assim na viabilidade de aplicação da tarefa prática no desenvolvimento da disciplina.
Expectativa versus realidade: experiências, percepções e desempenhos discentes frente ao ensino remoto
Authors: Irala Valesca Brasil , Blass Leandro , De Oliveira Casartelli Maria Regina , Saldanha da Silva Cristiano
Published: July 2021

Esta pesquisa busca descrever dois macro-construtos: a autoeficácia percebida (ao início e ao final do primeiro semestre remoto) e as expectativas (as esperadas ao início do semestre e as observadas ao final do mesmo semestre). Para tanto, foram analisados 135 estudantes que participaram de ambas as etapas de coleta de dados, em uma instituição pública brasileira de ensino superior, a partir da observação de médias e medianas e pelo Teste de Wilcoxon para grupos pareados. Também foram observadas as possíveis diferenças entre estudantes ingressantes e veteranos em termos de desempenho acadêmico. Ainda, estabeleceu-se um comparativo sobre o tempo de dedicação à Internet dos alunos para atividades acadêmicas e não-acadêmicas, antes e depois da experiência remota. Os indicadores de expectativas mostraram-se com maiores diferenças do que os de autoeficácia ao longo do semestre. Ainda, o tempo de uso de internet para atividades não-acadêmicas não sofreu mudanças, mas para as atividades acadêmicas houve alteração. Também, os alunos veteranos apresentaram resultados globais mais satisfatórios do que os ingressantes, o que reforça a necessidade de maior atenção institucional a esse seguimento.
ln vitro inhibition of beta-hematin formation and in vivo effects of Diospyros mespiliformis and Mondia whitei methanol extracts on chloroquine-susceptible Plasmodium berghei-induced malaria in mice
Authors: Olanlokun John Oludele , Adetutu Janet Adenike , Olorunsogo Olabode Olufunso
Published: July 2021

Background and aim

This study was carried out to investigate antiplasmodial activities of Diospyros mespiliformis (DM) and Mondia whitei (MW) in Plasmodium berghei-infected mice.

Materials and methods

Air-dried stem of DM and root of MW were soaked in methanol, decanted and concentrated to give extracts. Parts of these extracts were partitioned successively to give dichloromethane, ethylacetate and methanol fractions. Mice (18 ± 3 g) were infected with Plasmodium berghei-infected erythrocytes from a donor mouse and were treated with the extracts, while the drug control group received 10 mg/kg body weight of artesunate and the parasitized control received the vehicle (5% v/v DMSO). Percentage parasitemia and clearance were estimated from thin films of blood smear. Hematological parameters were determined using standard methods. Both extracts were also tested on in vitro inhibition of β-hematin formation.

Results, discussion and conclusion

Results showed that DM had the least percentage parasitemia (0.67%) and highest percentage parasite clearance (84.7%) while the MW had 0.89% percentage parasitemia and 79.7% clearance at the highest dose used after the seventh day relative to untreated control. The cell free antiplasmodial activity of the fractions and extracts of both DM and MW revealed that DM significantly inhibited β-hematin formation than MW. The packed cell volume, white blood cell count, Lymphocyte, Eosinophil, Monocyte and Neutrophil significantly increased in the treated groups compared with the control. The results showed that the DM had higher antiplasmodial activity.
Identifying and Evaluating Atypical Traits in Ancient Egyptian Glass Vessels attributed to the New Kingdom using Raw Data Analysis and Expert Assessment
Authors: Kemp Victoria , Rohan Rhiannon , Shortland Andrew
Published: July 2021

The descriptive data pertaining to the remaining, largely intact, glass vessels produced in ancient Egypt between the reigns of Tuthmosis IV (1401–1391 BCE) and Pinudjem II (959–945 BCE) contained in Die Glasgefäße im Alten Ägypten [The Glass Vessels in Ancient Egypt], was extracted and standardized to create a dataset that could be analysed to determine the most typical and atypical features of vessels attributed to the New Kingdom in the corpus. Seven descriptive categories were assessed based on the percentage of incidence to determine if a vessel could be defined as statistically “atypical.” An expert’s evaluation was employed as a second assessment method. The two methods identified 76 vessels from a total number of 320 vessels and agreed on 16 vessels considered as atypical, all of which had little or no provenance information. The resulting 76 vessels identified as “atypical” by the combined methods were subsequently compared with the respective provenance information and current location to determine patterns of collection and distribution throughout the world. The data showed that the Americas held the largest number of vessels that had little or no provenance data, including those held in private collections. The combined atypical tests identified that the Americas hold the largest proportion of atypical vessels. It is not the intention of this research to undermine the authenticity of vessels but to determine if data methods can be used to identify atypical traits in archaeological collections and to encourage the application of archaeometric testing to provide supporting information on statistically rare objects.
Healing of Internal Defects in a Compressive Stress Field Using the Plastic Properties of Materials
Authors: Bukhalov V. I , Perelmuter M. N , Popov A. L
Published: July 2021

Numerical simulation of defect healing process in the field of previously created compressive stresses is performed. Isotropic cylinders with small axisymmetrically located defects are used as samples. The pressure created the initial field of compressive stresses inside the cylinder. The defects were modeled as a small blind closed annular cavity or as a through annular cut located around the cylinder axis. In the first case, a numerical three-dimensional solution is considered. For the second defect, the plane stress state model was used. The problems were solved in both elastic and elastoplastic formulations with an ideally elastoplastic behavior of the material. The external pressure was varied from values significantly lower than the yield strength to the yield strength and (for the first problem) for values slightly exceeding it. Based on the results of the numerical solution, the radial displacements of the cavity sides parallel to the cylinder axis are obtained depending on the external pressure. We found the values of pressure at which the cylindrical surfaces of the void defect were in contact. For the blind cavity, at any external pressure, there were unhealed areas. Healing was assessed by the volume of the material filling the initial cavity at the initial residual stresses. The value of the newly formed contact pressure at a certain value of the compressive stresses was determined by the ratio of the height of the healed area to the cavity height. The evaluation of the healing effect for a through cut in the cylinder was performed by varying the size of the gap formed by the cut between the inner cylinder and the outer ring depending on the applied external pressure. When the gap is completely healed, the values of the maximal contact pressure in the notch zone are determined.
The Computational Method of Estimating Vibration Stress Levels for GTE Compressor Blades
Authors: Pivovarova M. V , Besschetnov V. A
Published: July 2021

At present, the process of designing a GTE involves a large amount of computational modeling. With the help of computational modeling, it is possible to predict a behavior of an engine part during engine operations before conducting experimental studies. For example, the numerical dynamic behavior analysis of compressor blades and prediction of dynamic stress levels during fluctuations in free modes are urgent problems. A high level of dynamic stress in the compressor blades in resonant modes can break a blade and stop an engine. In this paper, we propose a simple vibration stress estimation method for the compressor blades based on the calculation of natural frequencies and vibration forms. The method is based on a comparative analysis and scaling of stresses by the value of the total potential or kinetic energy. This estimation method is valid for local changes in the blade geometry, which do not lead to changes in the natural frequencies and vibration forms of the blades, assuming that the geometry change does not change the level of the aerodynamic excitation of the blade or its damping. At the stage of development or revision of the blade, a large number of variants of the blade geometry needs to be analyzed in order to reduce dynamic stresses. The proposed vibration stress estimation method has shown its high efficiency in developing and refining the geometry of the compressor blade. The vibration stress estimation method was tested using the rotor blade of a high-pressure compressor. As a result of the experimental study of the rotor blade, a high level of vibration stresses exceeding the permissible level was found for natural frequencies and vibration forms. To reduce the vibration stresses, measures were proposed to modify the geometry of the blade. For the modified blade geometry, the vibration stress estimation was performed with a prediction of the vibration stress values based on the manifested vibration forms. In order to verify the estimated vibration stress change, an experimental study of the modified blade was conducted. The vibration stress estimation method for the compressor blades was successfully verified.
The Refined Model of the Elastic-Plastic Dynamic Behavior of Reinforced Curved Panels Sensitive to Strain Rate
Authors: Yankovskii A. P
Published: July 2021

The initial-boundary value problem of dynamic elastic-viscoplastic deformation of flexible curved panels (shallow shells) with plane -cross and spatial reinforcement structures is formulated. The inelastic behavior of the materials of the composition components is described by the constitutive equations of the theory of plastic flow with isotropic hardening, and their sensitivity to strain rate is taken into account. The geometric nonlinearity of the problem is taken into account in the Karman approximation. The used kinematic and dynamic two-dimensional relations and the corresponding boundary conditions make it possible to describe, with varying degrees of accuracy, the mechanical bending behavior of shallow composite shells. This takes into account the possible weak resistance of such reinforced panels to transverse shears. In the first approximation, the used two-dimensional equations, the initial and boundary conditions degenerate into the relations of the traditional non-classical Ambartsumyan theory. For the numerical integration of the formulated nonlinear dynamic problem, an algorithm of time steps is applied, based on the use of an explicit scheme of the cross type. The elastoplastic and elastic-viscoplastic behavior of the reinforced cylindrical shallow shells under transverse dynamic loads generated by an air blast wave is investigated. Metal-composite and fiberglass thin-walled constructions are considered. It is shown that the refusal to take into account the dependence of the plastic properties of the components of the composition on the rate of their deformation does not allow adequately describing the inelastic dynamic behavior of both metal-composite and fiberglass shallow shells. It is shown that in the calculations of even relatively thin reinforced cylindrical panels (with a relative thickness of 1/50), the use of the Ambartsumyan theory leads to completely unacceptable results in comparison with the refined bending theory. It has been demonstrated that even for relatively thin curved fiberglass panels, replacing the traditional flat -cross reinforcement structure with a spatial structure with obliquely laid fiber families can significantly reduce not only the intensity of deformations in the binder, but also the maximum deflection values in modulus. For metal-composite shallow shells with a weakly expressed anisotropy of the composition, the positive effect of the indicated replacement of reinforcement structures is practically not manifested.
The Crack Growth in the Imitation Model of a GTE Turbine Disk under Operating Loading Conditions
Authors: Yarullin R. R , Shlyannikov V. N , Sulamanidze A. G
Published: July 2021

The paper presents the experimental results of growing surface cracks in the turbine disk of a gas turbine engine (GTE) under cyclic tension at room and elevated temperatures. The geometry of the imitation model of the GTE turbine disk with a stress concentration zone in the form of a bolt hole was justified. In order to ensure the similarity of the initial damage of the imitation model and the GTE turbine disc in the plane of symmetry of the stress concentration zone, a semi-elliptical notch was made. The loading conditions of the imitation model were developed based on results of a comparative stress-strain state (SSS) analysis of the stress concentration zone of the imitation model and the GTE turbine disc. As a result of the fatigue test of the imitation model at room and elevated temperatures, the experimental positions and sizes of the crack fronts with respect to the drop potential signal on the crack edges were obtained. The fixed positions and sizes of the crack fronts were used as the basis for the numerical calculation of the fracture resistance parameters. For the numerical studies, ten three-dimensional finite element models with different positions and sizes of the crack fronts were considered. The numerical calculation results based on the finite element method were used to determine the distributions of the elastic stress intensity factors along each crack front. The crack growth rate characteristics both on the free surface and at the deepest point of the crack front were obtained at room and elevated temperature conditions. A technique for the automation tests that simulate the block-type loading of the disk material at elevated temperatures was proposed.
Society for the Protection of the Health of the Jewish Population (OSE): Jewish Humanitarian Mission for over 100 Years
Authors: Potap Olga , Cohen Marc , Nekritch Grigori
Published: July 2021

The essay's primary purpose is to bring to the attention of readers interested in the history of the Jewish people that the dramatic 20th century is not only the victims of the Holocaust–and not only the heroism of the military on the battlefields. It is active resistance to barbarism–the rescue of defenseless people through daily civilian activities, nevertheless associated with a constant risk to life. This paper examines non-political and non-religious secular Jewish welfare society within Jewish political and national movements. This essay considers five historical periods of the activity of OSE. These periods are: 1912–1922; 1922–1933; 1933–1945; 1945–1950; 1950–present time. This chronological classification is somewhat imperfect; however, each period reflects the dynamic of functional changes in the initial tasks of the society to review the goals of the organization to satisfy the urgent needs of the European Jewish community in a debatable circumstance of the 20th–21st centuries.
Time, Moment, Eternity: Hieroglyphs and Meditations in Yakov Druskin’s Philosophy
Authors: Menshikov Andrey S.
Published: July 2021

In this article, the author explores the interest of the interwar intellectuals in “time, death, God”. This focus on temporality as an existential problem engendered some major philosophical projects, which aimed at complete revision of how philosophy should be done, including Henri Bergson, Edmund Husserl, Franz Rosenzweig. The main part outlines a philosophical project of Yakov Druskin who addressed the problem of temporality in a highly original manner. Druskin combined philosophical reflection on time in its existential meaning with the search for intellectual methods and linguistic techniques to transcend our ordinary reality. Among these methods, in Druskin’s works present at least two major modes—meditation and “hieroglyphs”—can be identified. Both methods, however, aim at “transforming rather than informing” and at enabling us to linger in a “certain equilibrium with a minor error”.
«Service to the Three Saints Mitrofan of Voronezh, Demetrius of Rostov and Tikhon of Zadonsk» by Bishop Jeremiah (Soloviev): the history of the text
Authors: Sidneva M. V.
Published: July 2021

The publication consists of a research article and the first publication of the source. The article presents a historical and source-oriented commentary on the service of Bishop Jeremiah (Solovyov) to three Russian prelates who were glorified in the 1860's Mitrofan of Voronezh, Demetrius of Rostov, and Tikhon of Zadonsk. The reason for the creation of this hymnographic monument was the intention of the former bishop of Nizhny Novgorod to consecrate one of the churches under construction in honor of these saints. When writing the service to the three saints, Bishop Jeremiah relied on a wide range of sources, including the works of St. Demetrius of Rostov and the penitential canon of Cyril of Turov. The publication is intended to illustrate Bishop Jeremiah's work as a hymnographer and to present a little-known example of a service to Russian saints composed during the Synodal period of the history of the Russian Church.
Sergey Nikitovich Savinsky (1924-2021) and the Historical Self-Awareness of Evangelical Christians-Baptists
Authors: Dyck J.
Published: July 2021

The article presents biographical information about the first confessional historian of Russian Evangelical Christians-Baptists, S. N. Savinsky. He authored a number of chapters on the Russian-Ukrainian Evangelical-Baptist community in a book titled “History of Evangelical Christians-Baptists in the USSR” (1989), until that time the only book on the history of his own denomination published during Soviet times. Described is his work as member of the Historical Commission of the All-Union Council of the Evangelical Christians-Baptists. The article traces four trajectories of the worldwide evangelical revival into Russia: the late German Pietism, the North America revival movement, the influence of the worldwide Evangelical Alliance, and the early German Pietism. S. N. Savinsky basic concepts of evangelical revival and uniqueness of the Russian Evangelical-Baptist community are analyzed.
Avaliação Acadêmica Multidimensional com o uso do “U-Multirank”
Authors: Prado Antonio
Published: July 2021

Avaliação de Instituições Acadêmicas é um tópico de grande interesse no mundo, e sempre trouxe muitas polêmicas. Esse assunto é atual no Brasil, pois a Capes estuda novas formas de avaliação para a Pós-Graduação brasileira. A idéia principal é usar um modelo multidimensional, de forma a valorizar aspectos que são importantes para Instituições acadêmicas e as comunidades onde estão inseridas, mas que não são captados pela avaliação atual, bastante focada em resultados gerados por pesquisas de ponta. Na ausência de uso de métodos multidimensionais de avaliação acadêmica no Brasil, é útil analisar experiências internacionais nessa área, para aprimorar o entendimento de como eles funcionam. Nesse cenário destaca-se o ranking acadêmico internacional “U-Multirank”, criado na Europa e que tem resultados desde 2014. O presente estudo analisará as Dimensões e Indicadores desse ranking e, com base nas Instituições de Ensino Espanholas, mostrará as correlações existentes entre Dimensões e Indicadores nesse país.
Does Nature-based Travel Promote Traveler’s Happiness in COVID-19?: A focus on Risk Perception, Attention Restoration Theory and Subjective Well-being
Authors:   The Tourism Sciences Society Of Korea, Jung San-Seol , Kim Kyoung-Bae , Lee Hoon
Published: July 2021

With the global spread of COVID-19, there have been constraints on tourism behavior, which are increasing the negative emotion of tourists. To recover from this negativity, tourists are pursuing domestic nature-based travel as much as possible in the current situation. This study aims to empirically confirm whether natural tourist destinations have the effect on helping tourist recover from COVID-inspired negativity and if perceived happiness is enhanced for those who traveled to natural tourists destination during the COVID-19 pandemic situation. In order to test the hypothesized model, data were collected from an online survey from September 5th to September 19th. A total of 742 of 845 responses were used for empirical analysis. The results of the study are as follows. First, it was found that physical risk perception did not affect perceived restorative environment, while psychological risk perception and socio-environmental risk perception had an impact on perceived restorative environment. Second, it was found that the perceived restorative environment had an impact on perceived attention restoration. Third, it was found that the perceived attention restoration had an impact on travel happiness (subjective well-being). This study is meaningful in that it theoretically verified the importance and positive role of domestic nature-based tourist destinations in a psychologically negative state. Based on the results of the study, natural tourism destination development directions were proposed for tourism business corporales and public institutions.
Bustamante Costa, Joaquín (2020): Fitonimia árabe ḥassāniyya. Los nombres de las plantas en el árabe del Sáhara Occidental y Mauritania, en Libros de las Isla 5, Cádiz, Editorial UCA y UCOPress, 440 pp.
Authors: Moscoso García Francisco
Published: July 2021

Reseña de Bustamante Costa, Joaquín (2020): Fitonimia árabe ḥassāniyya. Los nombres de las plantas en el árabe del Sáhara Occidental y Mauritania, en Libros de las Isla 5, Cádiz, Editorial UCA y UCOPress, 440 pp.
Cortés, Santiago, y Granados, Berenice (coord.) (2019), El rey que se ahogó. Relatos de Yunuén, Morelia, LANMO, 195. pp.
Authors: Rodríguez Juárez Sandybell
Published: July 2021

El rey que se ahogó. Relatos de Yunuén reúne un conjunto de testimonios —ricos, variados e interesantes—, que fueron narrados por los habitantes de la isla de Yunuén, en Pázcuaro, Michoacán. Santiago Cortés y Berenice Granados fueron los coordinadores de este libro, financiado por un proyecto Papyme y llevado a cabo por el Laboratorio Nacional de Materiales Orales (LANMO) de la Escuela Nacional de Estudios Superiores de la UNAM, campus Morelia.
Jovanović, Željko (2020): Twentieth-Century Sephardic Authors from the Former Yugoslavia. A Judeo-Spanish Tradition, Cambridge, Legenda (Studies in Hispanic and Lusophone Cultures, 41), 208 pp.
Authors: Alonso Miguel Álvaro
Published: July 2021

Reseña de: Jovanović, Željko (2020): Twentieth-Century Sephardic Authors from the Former Yugoslavia. A Judeo-Spanish Tradition, Cambridge, Legenda (Studies in Hispanic and Lusophone Cultures, 41), 208 pp.