bluuebunny/crossref_metadata_2025 huggingface dataset:
Online examination session: teachers’ and students’ satisfaction level
Authors: Baranova Tatiana , Kobicheva Aleksandra , Tokareva Elena , Bryant Charles
Published: July 2021

This paper is aimed at defining the satisfaction level of students and teachers with online examination session. To implement the study, we conducted online surveys for 2nd year bachelor students and 1st year master students (N=97) and online interviews with teachers (N=12). The analysis of received data indicated that students felt more satisfied with online examination session than teachers due to a number of reasons. Firstly, elder teachers faced technical problems on some steps of examination session. Secondly, teachers worried about the reliability of students’ testing results as they had access to any recourse or material and due to bad connection sometimes it was hard to hear or see students. Thus, some problems were revealed despite the general positive attitude to online examination session from students.
Ensuring students’ wellness: resources and demands in higher education
Authors: Ikatova Inna I. , Barynkina Irina V. , Amelina Lyubov V.
Published: July 2021

New technologies are changing higher education at an unprecedented scale, therefore to get a competitive edge societies round the world are trying to find new ways to meet emerging challenges by optimizing learning outcomes. The aim of the present article is to study the mitigating role of resources available to university students in the relation to demands, evaluate and compare their stress levels during Covid-19 lockdown and in-classroom learning using Demand-Induces Strain Compensation Model at Bryansk State University. Findings showed high stress levels during three months of remote learning, since physical and cognitive demands were poorly counterbalanced with relevant resources. In-person education demonstrated lower stress levels due to fewer demands and better resources in physical and emotional aspects. As to a cognitive aspect, the moderating role of resources was still insufficient, though the rate of cognitive demands was lower, compared to the remote learning. Consequently, it is essential to achieve an equilibrium between demands and matching resources to ensure students’ wellness. A range of didactic possibilities has been offered within the blended learning paradigm to enhance interaction, collaboration, confidence of students as independent and active learners. Fading techniques that encourage learners to become autonomous technology users by gradually removing prompts and making tasks more challenging have proved to be successful.
Competence-based approach: prerequisites and prospects for studying the mechanisms of managing the emotional response of schoolchildren
Authors: Verkhoturova Natalia
Published: July 2021

Emotional processes are the most important class of mental manifestations in human life, the state of which largely determines physical and social well-being, mental and somatic health, as well as the success of the subject in all types of his life. The accumulation and expansion of emotional experience, its development, consolidation and modification under the influence of purposefully organized education and upbringing, as well as the impact of cultural and conventional norms adopted in a particular society, consistently lead to the formation of a significant group of abilities, knowledge and skills that reveal the emotional literacy of an individual in management of emotional response and characterizing the behavior of the subject from the point of view of his rationality, consciousness, criticality, regulation, self-control and self-management. The presence of emotional literacy determines the social maturity of a person, which is revealed in his emotional competence when interacting with the social environment.
Factors of trans-boundary tourism sustainable development in dynamics of South-East Asia regionalization (the case of Thailand- Laos - China tourism cluster)
Authors: Sitikarn Bussaba , Kankaew Kannapat
Published: July 2021

One of the most notable tourism occurring in the global travel industry today is the growing of trans-boundary tourism especially in context of ASEAN countries. Thailand in particularly, has faced with the dramatically growth of tourist numbers across the border area of R3A (Thailand, Lao People’s Democratic Republic and the Southern Republic of China) in addition to immerging negative impacts to the destinations and their local communities. To maximize benefits from the situation, this study aims to investigate the potential and readiness of trans-boundary tourism system and types of tourism that promoting tourism linkage with-in the travelling route of R3A. Four case studies were investigated including Chiang Khong district in Thailand, Luang Namtha in Laos PDR, Xishuangbanna and Kunming in the Southern Republic of China.
Formation of mechanisms for state regulation of environmental investment activities in the region
Authors: Makhosheva Salima , Kandrokova Marina , Ivanov Zaur , Sabanchiev Anzor , Shardan Saida
Published: July 2021

The modern development of the Russian economy is characterized by conditions of socio-ecological and economic development, which create the preconditions for the formation of such a system of using natural resources in the processes of industrial production and consumption, which will be distinguished by rationality, ensure not only environmental, but also economic security of society, the well-being of the present and future generations of the population, assume the creation of necessary and sufficient conditions for sustainable development, which, in turn, will require the introduction of not only economic, technical, technological, social and other transformations, but also changes in the mechanisms of state control and regulation of investment processes of environmental orientation. In our opinion, the greatest improvement should be subject to the regulatory and legal mechanism of both state regulation and, in particular, local public self-government. This need is explained by the fact that in the territories of municipalities, there are sources of environmental pollution and industrial enterprises implementing eco-efficient investment projects. However, as the analysis of the regulatory framework has shown, almost all documents regulating the activities of municipal government bodies in the investment and environmental spheres are approved by laws and resolutions of the governments of the regions in which the municipalities are located. Hence, it can be concluded that the improvement of the regulatory mechanism of state and public regulation should be carried out in a comprehensive manner for both the regional and municipal levels of government.
The impact of human activity on the global warming
Authors: Evseeva Oksana , Evseeva Svetlana , Dudarenko Tamara
Published: July 2021

The global temperature of the planet is directly related to human activity. Landfills, vehicles, deforestation, production and, in particular, livestock, affect the temperature change on the planet and global warming. Greenhouse gas emissions, solid aerosol particles and soot, deforestation, methane, nitrous oxide and freons’ concentration in the Earth’s atmosphere are the key influencers on the changes in the global temperature. All of it is the result of human’s activities and needs the human control. The problem of the impact of the human activity on the global warming in environmental economics should be scrutinized in order to avoid the negative effects from its distribution. Research methods used: system analysis, synthesis, comparison and generalization and econometrics’ methodology. The main results include investigation into the impact of the human activity on the global warming (the level of global temperature as the main indicator) on the global world level. They showed that all of the chosen types of human activities influence on the global warming – rising temperature and industrial production and livestock have the greatest impact on global warming during the period.
Cost analysis at different energy sources for heating of an air-supported dome for indoor tennis
Authors: Gavrilov Ventsislav , Penkova Nina , Zlateva Penka , Mladenov Boian
Published: July 2021

Numerical analyses of the energy supply for heating of air supported structure for indoor tennis in Sofia via district heating, gas and liquid fuels are performed. The computational procedures are implemented through thermal balances of the structures, calibrated on the base of in situ measurements of the indoor temperature and the amount of the fuel, consumed at heating of an air supported balloon for tennis in University of Chemical technology and Metallurgy. The profitability of the different heating variants is estimated using the price of the energy and the systems.
Experimental COP evaluation of a 65-litre household refrigerator running with R600a
Authors: Alqaisy Saleh J. , Hmood Kamel S. , Aboaltabooq Mahdi Hatf Kadhum , Apostol Valentin , Pop Horatiu , Al Douri Jamal , Bădescu Viorel
Published: July 2021

A household refrigerator is a major energy consumer in all homes. The paper aims to evaluate based, on experimental data, the COP of a 65-liter household refrigerator operating with R600a. The main components and instrumentation of the experimental setup are presented. A mathematical model based on the energy balance of the refrigerated enclosure is developed in order to evaluate the COP. Three experimental data sets have been obtained in quasi-steady-state operating conditions. The results point out that the compressor power absorbed from the grid was 60 [W]. The maximum value for the cooling capacity is 81.73 W while the minimum value is 80.24 W. In terms of COP, the maximum value obtained is 1.362, while the minimum one is 1.337. The COP values obtained in the present study are in good agreement with the ones displayed by the manufacturer in the compressor datasheet. Future development is discussed.
Review regarding defrosting methods for refrigeration and heat pump systems
Authors: Al Douri Jamal , Hmood Kamel S. , Apostol Valentin , Pop Horatiu , Alqaisy Saleh J. , Beatrice Ibrean Elena
Published: July 2021

The paper presents a literature review regarding defrosting methods for household refrigeration and heat pumps. The literature review covers the period between 2008 and 2020. A number of 61 papers have been studied. The literature review was conducted by dividing the defrost methods into passive and active. Passive methods involve surface coating and off-cycle. The active defrost methods involve reverse cycle, ultrasonic vibration, hot–gas defrost, electric heating and hot fluid. Surface coating and ultrasonic vibration are recent defrost methods proposed in the literature. Also, recently, phase change materials have been used in household refrigerators to improve their efficiency. This is a topic that needs further investigation and is a subject of interest as it can lead to lower energy consumption during defrost cycles. From the present study, the research direction regarding the use of PCMs in defrost cycles can be highlighted.
Experimental research on obtaining pelletized feed recipes with applicability in semi-intensive aquaculture systems
Authors: Voicea Iulian , Moga Corina Ioana , Biriș Sorin-Ștefan , Constantin Gabriel-Alexandru , Boruz Sorin , Matache Mihai Gabriel
Published: July 2021

Romanian aquaculture can be economically sustainable and viable if the farm is profitable, the farm's income is secure, and the products are accepted by customers. In many cases, improving environmental sustainability can lead to optimizing economic sustainability. For example, a more efficient use of food and nutrients or reduced water and energy consumption are not only beneficial for the environment, but can also reduce costs. Growth in polyculture system, which represents the growth of several species of fish in the same space (pond, pool, basin, etc.), and diversification of supply can increase consumer confidence and thus economic sustainability. The diet must provide the fish with the nutrients necessary for growth (proteins with a plastic role) and provide the energy necessary for physiological processes. Quality food ensures good development, facilitates reproduction and prevents extremely harmful diseases in an aquaculture system. The paper presents a series of experimental recipes for pelletized feed made using an experimental model of small capacity. Nutrient pellets made for feeding fish from the Cyprinid family were analyzed in terms of gross energy value, ash content, moisture, mechanical durability over time, bulk density etc.
Strength analysis and modal analysis for the load-bearing structure of the equipment for opening and compartmentalizing watering furrows, using 1D
Authors: Cardei Petru , Sfiru Raluca , Oprescu Marius , Muraru Vergil , Muraru Cornelia
Published: July 2021

The paper proposes the analysis of the load-bearing structure of the equipment for opening and compartmentalizing watering furrows (EOCFW), using a 3D structural model, built with 1D finite element. Based on information from the experimental results of the EOCFW equipment, the load-bearing structure is supported and loaded. The results of the linear static analysis of the structure consist of the distributions of the relative displacement fields and the equivalent voltage in the structure. Also, the own frequencies of the structure and the deformed forms of the structure are obtained when it vibrates in its own ways with the lowest own frequencies. It shows how these results can be used. The field of relative displacements is used to assess the effects on the quality of the soil processing performed. The equivalent stress field is used to estimate the safety factor of the structure, by reference to the flow stress of the material from which the structure is built. The first four or five own frequencies are important for the prognosis of possible vibration regimes with resonance, their explanation and their amelioration. It emphasizes the ease with which the model can be modified to obtain improved or even optimized variants.
Analysis of the resistance frame of the equipment for opening and compartmentalizing watering furrows, using 3D finite elements
Authors: Cardei Petru , Oprescu Marius , Constantin Nicolae , Biriș Ștefan-Sorin , Muraru Sebastian
Published: July 2021

The proposed article sets out the results of the finite element structural analysis for the open and compartmentalised watering furrow equipment (OCWFE). It uses a 3D structural model with 3D finite elements. The analysis set out in the article is made in order to determine the field of relative displacement and equivalent stress in the load-bearing structure of the OCWFE. The structural model is generated in CAD-CAM. For the structural analysis, it is necessary the CAE model, which is obtained from the CAD-CAM model, mainly by eliminating gaps and interferences, but also by the techniques of realizing the contact between the components of the assembly and a careful mashing of the structure. The structural model thus created is supported and loaded in accordance with the experimental results from the literature. The relative displacement field and the equivalent stress field within the resistance frame of the OCWFE is obtained following the linear static analysis. The field of relative displacements is used to assess the effects on the quality of the work performed. The equivalent stress field is used to estimate the safety factor of the structure, by reference to the flow stress of the material from which the structure is built.
Biological water treatment in a recirculating aquaculture system
Authors: Laza Evelin-Anda , Caba Ioan Ladislau , Olan Mihai , Vladut Valentin
Published: July 2021

Biological water filtration is a process by which toxic compounds are removed from water using organisms. A well-sized biological filter is extremely important as part of a recirculating aquaculture system for fish farming. Biological water filtration equipment in aquaculture recycling systems is a technological set that restores the vital qualities of wastewater from fish ponds, thus allowing its reuse
Identifying new criteria for assessing the impact on the ecosystem generated by the establishment of Jerusalem artichoke crops on difficult and floodable soils
Authors: Nenciu Florin , Nae Gabriel , Milian Gabriela , Dumitru Iulian , Matei Gheorghe , Isticioaia Simona
Published: July 2021

Jerusalem Artichoke (Helianthus tuberosus L.) is a technical plant that manages to adapt very well to unfriendly environments, even in polluted or poor in nutrients soils and may serve in the near future as an important raw material for the food, chemical, and pharmaceutical industries. Furthermore, the plant is growing rapidly, producing large amounts of biomass and offers the possibility to be harvested up to 2 times a year, therefore presents a high potential to be used in the field of biofuel production. The plant's capacity to multiply easily by developing small tubers in the soil, allowing the production of economically advantageous crops, can be considered an advantage for biofuel producers, however this feature might be a drawback for agricultural land owners considering the very invasive behavior. The present paper aim to assess two Jerusalem Artichokes crops established on marginal soils, assessing productivity and the extensive impact on the ecosystem, paying a special attention to plant invasiveness tendencies.
Developing a comprehensive GIS tool to evaluate representative parameters regarding life comfort
Authors: Alionte Cristian-Gabriel , Rizescu Dana , Rizescu Ciprian Ion
Published: July 2021

In this paper, we present a tool dedicated to assessing life quality according to the notion of comfort which can link three aspects of noise, light, and air pollution with two aspects of thermal and odour discomfort because the beforementioned aspects are using different calculation methods of the parameters which are distinct and some of them are defined in the national or EU legislation. The authors developed a compressive database to evaluate representative quantities of energy loses. There were considered some performance indicators as: energy class, total specific energy consumption, CO2 equivalent emission index, the overall heat transfer coefficient of the building and characteristic temperatures, the corrected number of degrees days, and the duration of the heating season - at locality level.
Une force de portance élastohydrodynamique en matière molle
Authors: Salez Thomas , Saintyves Baudouin , Zheng Zaicheng , Bertin Vincent , Maali Abdelhamid
Published: July 2021

La friction est un phénomène omniprésent, aux conséquences majeures. Une stratégie pour réduire les frottements entre deux objets est d’intercaler une couche de fluide lubrifiant.

Pour des objets élastiques, le couplage entre leur déformation et la pression due à l’écoulement engendre des effets non triviaux, tels que l’apparition d’une force de portance.

Dans ce contexte, le problème d’une particule libre dans un fluide et proche d’une paroi molle a été traité théoriquement – avec des prédictions étonnantes.

La portance a été ensuite observée expérimentalement de manière indirecte, à diverses échelles.

Enfin, sa première mesure directe et quantitative à l’échelle nanométrique a été réalisée.
Optimiser la consommation énergétique des calculateurs quantiques : un défi interdisciplinaire
Authors: Auffèves Alexia
Published: July 2021

Jusqu’ici, la question de la facture énergétique d’un calculateur quantique n’a guère été abordée par les programmes de recherche – bien qu’elle amène actuellement l’industrie des semi-conducteurs à ses limites.

Existe-t-il un avantage quantique de nature énergétique ? Ou bien, au contraire, faudra-t-il une centrale nucléaire par ordinateur quantique ?

Cet article propose des pistes pour répondre à ces questions.
Du flou des images astronomiques à un prix Nobel de physique
Authors: Léna Pierre , Perrin Guy
Published: July 2021

Deux des lauréats du prix Nobel de physique 2020 sont primés pour leurs observations 1, qui ont confirmé l’existence d’un trou noir supermassif au centre de notre Galaxie. En améliorant considérablement, jusqu’à un facteur de plus de cent-mille parfois, la résolution spatiale des télescopes utilisés, ils ont exploré un véritable laboratoire de relativité générale, au plus près de cette singularité de l’espace-temps.

Ces gains en résolution résultent d’un franchissement de la limitation imposée par l’atmosphère terrestre, grâce à l’interférométrie des tavelures (1970), puis l’optique adaptative (1989), enfin la mise en service de télescopes optiques géants (ca. 2000), et du réseau interférométrique du Very Large Telescope européen.
The optical response of a complex nanodimer composed of a metal nanoparticle and a quantum dot: The effect of nanoparticle geometry
Authors: Biranvand Neda , Bahari Ali
Published: July 2021

The optical response of a hybrid structure consisting of a metal nanoparticle in the vicinity of a quantum dot under an external field is studied. The effect of the nanoparticle shape as it evolves from a sphere to a rod is investigated for various structural parameters. Significant changes are observed in the phase diagram of the optical response at the borders between Fano, exciton-induced transparency, suppression, and bistable regions. In the appropriate limits, the configuration exhibits a response where notable variations are particularly observed in suppression and bistable regions. In the presence of the nanorod, the suppression region is found as the beginning of bistability. Our calculations show that the nanorod can generate significant nonlinearities at the site of quantum dot in the bistable region, making the hybrid structure suitable for devices involving optical switching or information transfer. By considering the effect of other structural parameters, for example the configuration state, background dielectric constant, and interparticle distance, one can obtain additional control of the optical response of the system, engineering it to achieve particular objectives.
On the computation of intersection numbers for twisted cocycles
Authors: Weinzierl Stefan
Published: July 2021

Intersection numbers of twisted cocycles arise in mathematics in the field of algebraic geometry. Quite recently, they appeared in physics: Intersection numbers of twisted cocycles define a scalar product on the vector space of Feynman integrals. With this application, the practical and efficient computation of intersection numbers of twisted cocycles becomes a topic of interest. An existing algorithm for the computation of intersection numbers of twisted cocycles requires in intermediate steps the introduction of algebraic extensions (for example, square roots) although the final result may be expressed without algebraic extensions. In this article, I present an improvement of this algorithm, which avoids algebraic extensions.
Physical properties of YB66 and consideration of possible use for high-resolution X-ray optics
Authors: Bessas D. , Fukui H. , Sugimoto K. , Glazyrin K. , Sergueev I. , Levchenko G. , Dukhnenko A. , Filipov V. , Isnard O. , Ishikawa D. , Yoshikawa H. , Sakata O. , Baron A. Q. R.
Published: July 2021

A combined microscopic, i.e., powder and single crystal x-ray diffraction and inelastic x-ray scattering, and macroscopic, i.e., heat capacity, characterization was carried out on YB66 between 10 and 400K. The system crystallizes in a rather large unit cell with a lattice parameter of about 23.4Å at room temperature. The volume thermal expansion coefficient is found to be 3.9×10−5K−1 at 295K. A high Debye temperature above 1000K was determined using several methods, 1043(25)K, from heat capacity measurements, 1430(59)K, from elastic constants measurements, and 1690(198)K, from thermal expansion measurements. The thermal transport is modeled as a collection of Einstein oscillators with an Einstein temperature of 194(2)K. The C11 and C44 elastic constants are above 400 and 150GPa, respectively. The average speed of sound in YB66 is estimated to be 9631(380)m/s, similar to the average speed of sound in corundum, 10000m/s. The large volume of the unit cell and the stiffness of the crystal structure make YB66 a promising candidate for high-resolution x-ray monochromatization applications. Candidate reflections for high-resolution resonant inelastic x-ray scattering are indicated and potential pitfalls relevant to the quality of crystals and multi-beam cases are mentioned.
Synthesis and thermochemical redox cycling of porous ceria microspheres for renewable fuels production from solar-aided water-splitting and CO2 utilization
Authors: Abanades Stéphane , Haeussler Anita , Julbe Anne
Published: July 2021

Porous ceria-based architected materials offer high potential for solar fuels production via thermochemical H2O and CO2-splitting cycles. Novel porous morphologies and micro-scale architectures of redox materials are desired to provide suitable thermochemical activities and long-term stability. Considering particle-based solar reactors, porous ceria microspheres are promising because of their excellent flowability and large surface area. In this work, such porous microspheres with perfect spherical shape, high density, and interconnected pore network were fabricated by a chemical route involving ion-exchange resins. The method involved the cationic loading of the resin in an aqueous medium followed by thermal treatment for oxide formation and porous microstructure stabilization. The utilization of these microspheres (∼150–350 μm in size) as redox materials for solar fuel production was investigated in packed-bed solar reactors (directly and indirectly irradiated). Superior redox performance was obtained for the pure ceria microspheres in comparison with other morphologies (powders and reticulated foams). Low pO2 values thermodynamically favored the reduction extent and associated fuel yield, whereas high pCO2 kinetically promoted the oxidation rate. The highest fuel production rate reached 1.8 mL/min/g with reduction step at 1400 °C, low total pressure (∼0.1 bar), and oxidation step below 1050 °C under pure CO2. Low pressure during reduction both improved reduction extent (oxygen under-stoichiometry δ up to 0.052) and associated fuel production yield (331 μmol/g CO). After 19 redox cycles (∼32 h under high-flux solar irradiation), the porous microspheres maintained their individual integrity (no agglomeration), spherical shape, and internal porosity, with great potential for stable fuel production capacity in particle-based solar reactors.
Enhancing the effective critical current density in a Nb superconducting thin film by cooling in an inhomogeneous magnetic field
Authors: Chaves D. A. D. , de Araújo I. M. , Carmo D. , Colauto F. , de Oliveira A. A. M. , de Andrade A. M. H. , Johansen T. H. , Silhanek A. V. , Ortiz W. A. , Motta M.
Published: July 2021

Quantitative magneto-optical imaging of a type-II superconductor thin film cooled under zero, homogeneous, and inhomogeneous applied magnetic fields indicates that the latter procedure leads to an enhancement of the screening capacity. Such an observation is corroborated by both B-independent and B-dependent critical state model analyses. Furthermore, repulsive (attractive) vortex–(anti)vortex interactions were found to have a decisive role in the shielding ability, with initial states prepared with vortices resulting in a shorter magnetic flux front penetration depth than those prepared with antivortices. The proposed strategy could be implemented to boost the performance of thin superconducting devices.
The generalized Plücker–Klein map
Authors: Krasnov V. A.
Published: July 2021

The intersection of two quadrics is called a biquadric. If we mark a non-singular quadric in the pencil of quadrics through a given biquadric, then the given biquadric is called a marked biquadric. In the classical papers of Plücker and Klein, a Kummer surface was canonically associated with every three-dimensional marked biquadric (that is, with a quadratic line complex provided that the Plücker–Klein quadric is marked). In Reid’s thesis, this correspondence was generalized to odd-dimensional marked biquadrics of arbitrary dimension

. In this case, a Kummer variety of dimension

corresponds to every biquadric of dimension

. Reid only constructed the generalized Plücker–Klein correspondence. This map was not studied later. The present paper is devoted to a partial solution of the problem of creating the corresponding theory.
Embedding theorems related to torsional rigidity and principal frequency
Authors: Avkhadiev F. G.
Published: July 2021

We study criteria for the finiteness of the constants

in integral inequalities generalizing the Poincaré–Friedrichs inequality and Saint-Venant’s variational definition of torsional rigidity. The Rayleigh–Faber–Krahn isoperimetric inequality and the Saint-Venant–Pólya inequality guarantee the existence of finite constants

for domains of finite volume. Criteria for the existence of finite constants

for unbounded domains of infinite volume were known only in the cases of planar simply connected and spatial convex domains. We generalize and strengthen some known results and extend them to the case when

. Here is one of our results.

Suppose that

and

, where

is a compact set and

is either a planar domain with uniformly perfect boundary or a spatial domain satisfying the exterior sphere condition. Under these assumptions, a finite constant

exists if and only if the integral

is finite, where

is the distance from the point

to the boundary of

.
Plancherel–Rotach type asymptotic formulae for multiple orthogonal Hermite polynomials and recurrence relations
Authors: Aptekarev A. I. , Dobrokhotov S. Yu. , Tulyakov D. N. , Tsvetkova A. V.
Published: July 2021

We study the asymptotic properties of multiple orthogonal Hermite polynomials which are determined by the orthogonality relations with respect to two Hermite weights (Gaussian distributions) with shifted maxima. The starting point of our asymptotic analysis is a four-term recurrence relation connecting the polynomials with adjacent numbers. We obtain asymptotic expansions as the number of the polynomial and its variable grow consistently (the so-called Plancherel–Rotach type asymptotic formulae). Two techniques are used. The first is based on constructing expansions of bases of homogeneous difference equations, and the second on reducing difference equations to pseudodifferential ones and using the theory of the Maslov canonical operator. The results of these approaches agree.
Role of beam oscillation on electron beam welded zircaloy-4 butt joints
Authors: Nayak Lord Jaykishan , Roy Gour Gopal
Published: July 2021

Effect of beam oscillation on microstructure, mechanical properties and corrosion behaviour of electron beam butt weld of zircaloy-4 was investigated. Joints made with beam oscillation demonstrated higher ductility, toughness and notch tensile strength and higher corrosion resistance than the joints prepared without beam oscillation. Heat mixing and faster cooling associated with beam oscillation restrict unidirectional crystal growth favouring the development of a more uniform, fine basketweave widmanstätten structure in the fusion zone. Improvement in mechanical and corrosion properties using beam oscillation was attributed to the development of a more uniform microstructure, lesser segregation and lesser intermetallic precipitation in the fusion zone.
Ni-doping effects on the c-BN structural and electronic properties from density functional theory calculations
Authors: Ramadhan M R , Piliang M Z
Published: July 2021

Cubic boron nitride (c-BN) is known for its hardness parameter and wide range of electronic applications due to its band gap value. Here we investigated the doping effect of Ni atom on the c-BN system within the framework of density functional theory calculation. Generalized gradient approximation (GGA) is utilized as the exchange-correlation energy to estimate bulk modulus and band gap parameters. Supercell structure is consists of 8-unit cells in the formation of 2 × 2 × 2, with a single Ni atom replacing either B or N atoms. We observed that the bulk modulus of the c-BN type structure is slightly decreased followed by an increase of the lattice constants with the addition of Ni atoms to either B or N atoms. The mid-gap state introduced by Ni atom is apparent in both cases which effectively reduces the band gap of the c-BN system.
Synthesis of Magnetite Fe3O4 from Laterite Iron Rock as Microwave Absorber Material
Authors: Silvia L , Aslama B , Novialent E , Zainuri M
Published: July 2021

Synthesis of magnetite from laterite iron rock material was successfully introduced as microwave absorber material. In this research, magnetite has been made from laterite iron rock, Tanah Laut, South Kalimantan, Indonesia to be laterite iron sand was achieved by a simple method. Magnetite with paint coating is applied to steel grade A type AH36. The sample was characterized by an X-ray fluorescence spectrometer (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM) to investigated element composition, crystal structure, the morphology of particles, hysteresis loops of the magnetic sample, respectively. Based on the experiment, the magnetic particle properties have saturated magnetization of 120 emu g−1 and the coercive force of 0.05 T. VNA to investigate the absorption characteristics of microwaves in a frequency range between 8-12 GHz. The results showed that the reflection loss of magnetite is higher than uncoated steel samples. The sample has a maximum reflection loss value of −14.4 dB at 8 GHz with a sample thickness of 4 mm.
Surface Temperature Distribution on Aluminum Hollow Heated Using Two Pairs of Thermoelectric
Authors: Putro T , Triqadafi A O , Sakti S P
Published: July 2021

In the development of a gas sensor using Quartz Crystal Microbalance (QCM), the temperature of the headspace needs to be controlled. In this work, the temperature distribution of the aluminum hollow as a headspace was observed using a thermal imaging camera. In addition, the heating rate was also measured. The aluminum hollow was a square hollow with a dimension of 40mm x 40mm with a length of 20cm. The hollow thickness was 1 mm. The aluminum is heated using two pairs of thermoelectric that are mounted opposite each other. The aluminum surface temperature was set at 70 ° C and observed using the Fluke TiS20 thermal imaging camera. We found that the temperature distribution on the surface in the adjacent direction to the thermoelectric surface was evenly distributed with a temperature difference of 1°C. In the parallel direction, the temperature difference of 1°C existed in a length of 33.3 mm. It suggests that placement of the sensor with a temperature difference of less than 1°C can be varied in an area of 40mmx33.3mm.
The Effect Of Rainfall On The Detection Of Standing Water On Runway
Authors: Firdiyan N , Muntini M S
Published: July 2021

The need for knowledge about the presence of water on the runway is very urgent to be a concern. The existence of puddles on the runway can cause problems for aircraft, such as slip due to low friction. According to The National Transportation Safety Committee (NTSC), 32% of flight accidents in Indonesia were caused by a slippery runway. The existence of water on the runway cannot be separate from the role of rain as a source of water that inundates the runway. To be able to determine the potential for inundation, sensors are needed to measure three parameters; rainfall, rain intensity, and standing water detection. By placing a rainfall sensor and a standing water detector, it can detect the effect of rainfall in detecting standing water on the runway. This is shown in the rainfall test as a support for a standing water detector on the runway where the average wind speed of 5.14 m/s during the test on the runway. Through the analysis of the measurement of detectors to present the data is greatly influenced by the several conditions of rainfall, factor of rainfall and rainfall type.
Evaluation of Acoustic parameters at the ITS Science Tower Auditorium as a Multi-function Room
Authors: Suyatno  , Indrawati S , Pratiwi A N , Prajitno G
Published: July 2021

Acoustic parameters of a room affect the information received by listeners. Several acoustic parameters need to be met so that the information conveyed in a room can be clearly understood by listeners. The acoustic parameters include background noise, SPL distribution, reverberation time (RT), Clarity (C80, C50), and Definition (D50). This paper discusses the evaluation of acoustics parameters in the ITS science tower auditorium. The auditorium has a square shape with a volume of 3,387 m3. The evaluation was carried out using the impulse response method in an unoccupied auditorium without a chair. Based on the measurement results when unoccupied without a chair, It was found 27-31.6 dB, 64.5-76.5 dBA, 3.3-4 s, -5 to 1 dB and 8-40% for background noise, SPL, RT, C80 and D50 at the frequency of 1000 Hz, respectively. This shows that the auditorium does not yet fulfill a multi-function room. Consequently it is necessary to improve acoustic conditions through simulations with the addition of chairs, people, and loudspeakers. The simulation results in the auditorium obtained SPL of 78.32-94.2 dBA, RT of 0.95s, and an average of C80 of 4.01 dB, which indicates that the auditorium is closer to a multi-function room than before.
Measurement of Multichannel Analysis of Surface Wave in the South of Pangandaran as an Effort for Earthquake Hazard Mitigation
Authors: Susilanto P , Prajitno P , Rohadi S , Perdana YH
Published: July 2021

The Regency of Pangandaran is located on the southern side of West Java, surrounded by local faults, and close to the Indo-Australia and Eurasian subduction zone, causing the area to feel the earthquake’s impact often. Tasikmalaya Earthquake M 7.3, on September 2, 2009, was felt strong and has caused damage in this area. Therefore, mitigation efforts are critical to reducing the earthquake impact. This study aims to determine the classification of soil types in the southern Pangandaran based on 1D Vs up to 30 m depth (Vs30) measured by the Multichannel Analysis of Surface Wave (MASW) method. The study used the SNI 1726-2012 as the categorization of soil types based on Vs30. To clarify, the Vs profile made the cross-section from west to east part in 2D. The results show that hard and medium soils dominate the research area with Vs30 values between 210 - 627 m/s that make the area relatively safe from the potential of strong earthquake shocks. However, the southern part of Cijulang, Parigi, and Pangandaran districts have medium soil types that are relatively thick. Those parts may indicate the potential for stronger earthquake shocks.
Simulation of spiking activities neuron models using the Euler method
Authors: Syahid A , Yuniati A
Published: July 2021

Simulation of neuron spiking activity models has been carried out using the Euler method. This study aims to simulate spiking activity in a neuron model. The neuron model used is the Hodgkin-Huxley neuron model, Integrate and Fire neuron model, Wilson neuron model, and Izhikevich neuron model. The research was conducted by implementing the mathematical equations of each neuron model used and then recording the membrane potential changes from time to time using the Euler method in MATLAB. The different forms of spiking activity were done by varying the variable’s value in each mathematical equation of a neuron model that describes the processing of action potentials (spikes) influenced by ion channel activity. The results showed that the Integrate and Fire neuron models produce regular spiking (RS), Hodgkin-Huxley neuron models have regular spiking (RS) forms, Wilson neuron models produce regular spiking (RS), fast-spiking (FS), and intrinsic bursting (IB), Izhikevich neuron model produces regular spiking (RS), fast-spiking (FS), intrinsic bursting (IB), chattering neurons (CH), and low threshold spiking (LTS). The complexity of the variables used and the spiking activity generated by each neuron model can provide an overview of computational efficiency and proximity to actual biological neurons.
Fast-Forward of Local-Phased-Regularized Spinor in Massless 2+1-Dimensions Adiabatic Dirac Dynamics
Authors: Sugihakim Ryan , Setiawan Iwan , Gunara Bobby Eka
Published: July 2021

We discuss a method of controlling Dirac dynamics in (2+1)-dimensions using adiabatic fast-forward method proposed by Masuda-Nakamura. Due to infinitely large amount of time of adiabaticity, we have to use an infinitely large scaling factor to shorten the time interval. Thus, we need a regularization to remove this infinity. Our strategy is analogue to adiabatic fast-forward of Schrodinger equation. That is using an auxiliary Hamiltonian but now we use two phase factors applied to the components of spinor. We applied to a case where a system is controlled by uniform magnetic field.
Effect of FSP parameters on microstructure evolution and mechanical properties of AZ31 magnesium alloy
Authors: Cha Suna , Hou Hongliang , Zhang Yanling , Guo Enyu , Wu Shaojun
Published: July 2021

To investigate the microstructure evolution and mechanical properties of materials treated by friction stir processing process at various the shoulder sizes and rotating speeds of the tool, a series of friction stir processing experiments were carried out on the AZ31 magnesium alloy with thickness of 4mm by using tool shoulder sizes of 12, 16 and 18mm, and two kinds of rotating speeds of 750r/min and 1500r/min with a constant feed speed of 60mm/min were supplied. Based on the analysis of morphology and mechanical properties of the materials, results demonstrated that reduction of tool shoulder size and rotating speed would contribute to more remarkable the grain refinement effect and affect the strong texture and extreme density strength of the material, leading to higher microhardness. However, lower mechanical properties of yield strength and tensile strength were obtained at these parameters owing to the existence of internal organization defect and stronger defect sensitivity of it. All of the findings would further deepen the understanding of the technique of friction stir processing and contribute to the application of AZ31 magnesium alloy treated by friction stir processing.
A bibliometric analysis of research on acoustic emission for nondestructive testing
Authors: Yan Yu , Yang Zhensheng , Li Haoda , Jiang Chenming
Published: July 2021

Acoustic emission (AE) testing has been an active area of research globally for many decades. The present work is a comprehensive overview based on bibliometric analysis to investigate the application of AE research. The publication trends, key areas, organizations, countries, and sources and publications of AE applications are presented to address the following basic questions: what are the publication sources and trends, what are the key areas, and which countries and organizations are active in AE research? The influences of various AE subjects and topics are also discussed. With the help of the Web of Science Core Collection database and the specialized bibliometric analysis tool VOSviewer, the results are visualized properly, and it is found that AE research is currently developing rapidly.
Temperature dependent performance of lead phthalocyanine phototransistors
Authors: Li Yao , Pan Miao , Zhang Zheng , Wu Rong , Zhang Caizhen , Liu Chunjuan
Published: July 2021

In order to heighten their near infrared light-sensitive characteristics, lead phthalocyanine (PbPc) phototransistors were prepared by vacuum evaporation at various substrate temperatures (Ts) of 60°C, 100°C, 140°C and 180°C. The crystalline texture, absorption spectrum and surface morphology of PbPc films were measured. The light-sensitive characteristic measurement results indicated that the photoresponsivity (R) and specific detectivity (D*) of the devices first rise and dwindle asTsgrows and a best performance is gained atTs= 100°C. Research on the correlation between substrate-temperature-dependent film properties and device performance showed that the crystal texture, interconnection of grains, light absorption and carrier mobility of PbPc films could be varied by substrate heating, and thereby causing the variations in the device performance forRandD*. Moreover, a model semi-quantitatively describing the variation of photocurrent with optical absorption coefficient and carrier mobility was set up, and some numerical calculations were made base on the model presented.
Evaluation of 3-methacryloxypropyltrimethoxysilane organic layered double hydroxide on the aging resistance of bitumen
Authors: Zhang Canlin , Chen Minxuan , Wang Ting , He Jun , Chen Guochuan , Xu Song , Hu Changbin
Published: July 2021

To enhance and lengthen the anti-aging performance and service lifetime of bitumen, 3-methacryloxypropyltrimethoxysilane grafted layered double hydroxides (LDHs) was synthesized and exploited to modify bitumen. The contact angle of organic LDHs (OLDHs) increased from 17.8° to 39.2°, the hydrophilic of OLDHs obviously decreased in comparison with LDHs, which contributed to disperse more uniformly in bitumen. Furthermore, the stability of LDHs in bitumen became better after 3-methacryloxypropyltrimethoxysilane modification. After aging, the penetration and ductility of bitumen markedly declined, correspondingly, the softening point and viscosity remarkably rose, the physical performance of bitumen were deteriorated seriously. The addition of LDHs and OLDHs could restrain the properties degradation after aging, enhance the anti-aging of bitumen, and OLDHs exhibited much more excellent, because of the outstanding stability in bitumen.
The Zoom Boom: How Video Calling Impacts Attitudes Towards Aesthetic Surgery in the COVID-19 Era
Authors: Chen Jonlin , Chow Amanda , Fadavi Darya , Long Chao , Sun Alexander H , Cooney Carisa M , Broderick Kristen P
Published: July 2021

Background

The COVID-19 pandemic has led to the widespread adoption of video calling. A parallel growth in aesthetic surgery demand has been documented.

Objectives

The authors sought to identify associations between video call engagement and aesthetic surgery attitudes.

Methods

We distributed a cross-sectional survey via Amazon Mechanical Turk in November 2020. Respondents were asked to report their time spent video calling, video calling applications and features (eg, virtual backgrounds) they utilized, and aesthetic surgery attitudes employing the 15-item Acceptance of Cosmetic Surgery Scale (ACSS; higher scores indicate greater acceptance). ACSS scores were compared between video call users and non-users employing t tests. Pearson’s correlation coefficient was employed to quantify associations between ACSS scores and time spent on calls and multivariable analysis to estimate associations between video call engagement and ACSS scores.

Results

A total of 295 respondents (mean age, 37.6 years; 49.5% female) completed the survey. Across all video call applications surveyed, video call users had higher ACSS scores than non-users. Increased time respondents spent looking at their own face on video call was moderately associated with higher ACSS scores (r = 0.48, P < 0.01), whereas time spent looking at another person’s face was not associated with a change in ACSS scores (r = 0.09, P = 0.11). Increased video call utilization was associated with higher ACSS scores.

Conclusions

Increased video calling utilization is associated with increased acceptance of aesthetic surgery. Although the clinical significance of ACSS scores can be better elucidated, plastic surgeons should consider the effects of video calling on patient motivations for aesthetic surgery in the COVID-19 era.
News in Astronomy & Geophysics – August 2021
Authors: Bowler Sue , Gunn Alastair
Published: July 2021

A digest of some of the big stories from the past two months