bluuebunny/crossref_metadata_2025 huggingface dataset:
Research regarding the common problems of design of the bunkers – A review
Authors: Petre Ancuta Alexandra , Stanciu Mariana Mădălina , Mihalache Dumitru Bogdan , Dumitru Dragoș
Published: July 2021

Understanding the behavior of granular material in a bunker not only helps to design properly and achieve the correct granular flow, but also needs the engineer to ensure that the bunker is properly designed and conducted to withstand the tasks and demands exercised during its operation. Small and shallow bunkers are commonly used in industry when free space is limited. Shallow bunkers induce the flow of the funnel, which can cause problems such as segregation and agglomeration of the material inside it, which leads to considerable damage to the final product. The design and location of a suitable power supply and an appropriate outlet is still critical and is perceived rather as a science.

The paper presents some innovative solutions related to the design, modeling and construction of solid material storage and unloading bunkers.
Research on Exhaust Gas Cleaning System (EGCS) used in shipping industry for reducing SOx emissions
Authors: Vasilescu Mihail-Vlad , Dinu Dumitru , Panaitescu Mariana , Panaitescu Fanel-Viorel
Published: July 2021

Nowadays maritime transportation develops environmental pollution issues. On 1st of January 2020 “International Maritime Organization (IMO)” give a new amendment which limits the sulphur content in the fuel oil used on board ships operating outside designated emissions control area (ECA) to 0.50% m/m – a significant reduction from previous limit of 3.5 %. In ECA the sulphur content in the fuel must be maximum 0.10% m/m. In order to comply with the new regulation maritime industry has to search for new methods of reducing the SOx emissions. This article major points are: environmental pollution due to maritime transportation nowadays; methods for shipping industry to comply with IMO 2020 amendment; the use of an EGCS (Exhaust Gas Cleaning System) in order to reduce the output of SOx; discharge washwater chemistry; titration curve and dilution requirement; use CFD modeling in order to determine the expected flow and mixing profiles for the discharge washwater of an acidic effluent waste stream from ship into the ocean; comparison between the manufacturer system specification and the CFD modeling results; conclusions.
Models to estimate river temperature. Example for Danube, at Oltenița in the context of climate change and anthropic impact
Authors: Gogoașe-Nistoran Daniela-Elena , Ionescu Cristina Sorana , Opriș Ioana
Published: July 2021

Daily variation of Danube River temperature measured at Oltenitț gauging station over 9 years (2008-2016) was analysed in comparison with the air temperature measured by satellite in the same location between 1979-2020. Air temperature shows a nearly 2°C increase over the 40-years period, which can be attributed to both climate warming and anthropic impact. Water temperature was modeled with a sinusoidal function and variation with discharge was discussed. Long-term trend of hourly surface air temperature variation was obtained from Open Weather data. Air - water temperature dependency was fitted with a logistic function with good approximation. Resulting correlations help predict water temperature as a function of satellite - measured air temperature.
Mean field model of phase transformations in steels during cooling, which predicts evolution of carbon concentration in the austenite
Authors: Bachniak Daniel , Kuziak Roman , Szeliga Danuta , Pietrzyk Maciej
Published: July 2021

The objectives of the paper were twofold. The first was exploring possibility of fast and reliable modelling of phase transformations during cooling of steels, accounting for the evolution of the carbon concentration in the austenite. Existing discrete models require long computing times and their application to optimization of industrial processes is limited. Therefore, a model based on the modified JMAK equation was proposed. Control of the carbon concentration in the austenite during ferritic and bainitic transformations allowed to predict incomplete austenite transformation and occurrence of the retained austenite. Moreover, prediction of the onset of pearlitic transformation after the bainitic was possible. The model was validated by comparison the predictions with the results of physical simulations. Numerical simulations for various industrial processes were performed. Problem of the difference in the incubation time between isothermal and constant cooling rate tests was raised.
Effect of strain ratio on hydrogen permeability properties of low carbon enamel steel
Authors: Uzun Ramazan , Başkaya Ümran , Çetin Zafer , Kılıç Yasemin , Gündüz Oğuz , Bakkaloğlu Adem
Published: July 2021

In this study, the effect of varying strain levels on hydrogen permeability properties were investigated. Distinct strain levels (10% and 40%) were carried out on the deep drawing test samples by using Marciniak die to simulate the forming process. Amount of strain on deep drawn material was calculated by GOM’s ARAMIS 3D deformation measurement system. Hydrogen diffusion coefficient and permeation time were calculated by using Helios II system. Light optical microscope (LOM) and scanning electron microscopy (SEM) were used for microstructure characterization. Automated inclusion/precipitation analysis was performed by Thermoscientific Explorer-4. By this study, it is aimed to understand the hydrogen permeation properties of ultra-low carbon IF steel material with varying strain values. Finally, it was determined that number of inclusion/precipitation per mm2 was significantly increased as a function of strain ratio, which improves hydrogen permeation properties.
The effect of rotational speed on quality of sound vertical centrifugal castings tin
Authors: Tattimani Mahantesh S. , C.Y. Maheswar , Reddy Babu , Badi Shrikant , Ambadas  , Malipatil Anandkumar S.
Published: July 2021

Centrifugal casting plays a key role in manufacturing processes. In this process, the flow of the molten metal in particular, plays a significant role in defining the quality of final cast tube. The current study is an experimental work that focuses on the effect of fluid flow speeds on the quality of final cast product. The study was conducted using the vertical centrifugal casting with tin as the primary raw material. It is observed from the study that for the given manufacturing conditions, a speed 1050 rpm produced the sound castings. The micrographic studies of these cast products revealed an excellent grain structures. The improvement in the material hardness was also observed.
The application of the optimization principle in the Italian and European context
Authors: Contessa G.M. , De Crescenzo S.A. , Rossi P.
Published: July 2021

The transposition of Directive 2013/59/Euratom has projected Italian radiation protection into the new safety culture, in which optimization is a multidisciplinary process pursuing a suitable balance among different risks. The fundamental tools in the application of the optimization principle are source-related dose constraints, introduced by the Directive to define the range of options to be considered. This article analyzes some critical issues in their use when managing radiation protection at work in any planned, existing or emergency exposure situation, which involves a risk from exposure to ionizing radiation. Simplified procedures and customized guidelines are outlined from international organizations, such as IAEA, OECD/NEA, and the European ALARA Network (EAN), paving the way to a correct implementation of the optimization principle.
Computational design of moiré assemblies aided by artificial intelligence
Authors: Tritsaris Georgios A. , Carr Stephen , Schleder Gabriel R.
Published: July 2021

Two-dimensional (2D) layered materials offer a materials platform with potential applications from energy to information processing devices. Although some single- and few-layer forms of materials such as graphene and transition metal dichalcogenides have been realized and thoroughly studied, the space of arbitrary layered assemblies is still mostly unexplored. The main goal of this work is to demonstrate precise control of layered materials' electronic properties through careful choice of the constituent layers, their stacking, and relative orientation. Physics-based and AI-driven approaches for the automated planning, execution, and analysis of electronic structure calculations are applied to layered assemblies based on prototype one-dimensional (1D) materials and realistic 2D materials. We find it is possible to routinely generate moiré band structures in 1D with desired electronic characteristics such as a bandgap of any value within a large range, even with few layers and materials (here, four and six, respectively). We argue that this tunability extends to 2D materials by showing the essential physical ingredients are already evident in calculations of two-layer MoS2 and multi-layer graphene moiré assemblies.
Optimizing the differential connection schemes for detecting 3D magnetic perturbations in DIII-D
Authors: Munaretto S. , Strait E. J. , Logan N. C.
Published: July 2021

Optimizing the differential pair connection scheme (i.e., the set of pairs) of a toroidal array of magnetic sensors dedicated to measuring slowly rotating asymmetric fields can enhance the mode number detection capability and failure-resilience. In this work, the condition number obtained from singular value decomposition of the design matrix is used as a metric to evaluate the quality of a connection scheme. A large number of possible pair connections are usually available, so evaluating all of them may require extensive use of computational resources and can be very time-consuming. Alternative methods to reduce the number of pairs evaluated without losing the capabilities of toroidal mode detection are presented in this paper. Three examples of the applications of such analysis for the 3D magnetic diagnostic system of DIII-D are also presented: the addition of two new toroidal arrays with n > 3 detection capabilities, the modification of an existing toroidal array in the low field side of the machine to accommodate the addition of a helicon antenna, and the design of changes in several toroidal arrays in the high field side to accommodate the addition of a lower hybrid current drive antenna on the center post.
Thomson scattering of a vector Bessel vortex beam by a non-relativistic electron
Authors: He Jinchong , Li Haiying , Xu Bin , Bai Lu , Wu Zhensen
Published: July 2021

Thomson scattering of a vector Bessel vortex beam (VBVB) by a non-relativistic electron is studied in this paper in order to explore the prospects of vortex beams in Thomson scattering diagnostic in ionospheric or laboratory plasmas. Combining with the plane wave angular spectrum representation of a VBVB, the expressions of scattered electric and magnetic fields are derived with the aid of Thomson scattering theory. The scattered power per unit solid angle and the frequency spectrum of the scattered field in the backscatter direction are simulated numerically, and the effects of polarization, topological charge, half-cone angle, and the electron's motion are analyzed in detail. The results show that the polarization affects the spatial distribution of scattered power. The distance between the electron and the observer's location, where maximum power is received, is affected by the topological charge, and the gaps between sub-maxima are related to the half-cone angle. These characteristics are the manifestation of the retarded effect in radiation. The amplitude spectrum of scattered field is analyzed in which a feature of double peaks is observed. The frequency shifts of peaks are the sum of the shifts brought by the electron's velocity components parallel and perpendicular to the beam's axis. The work provides a significant theoretical foundation for deeply investigating the Thomson scattering of vortex beams by plasmas and is meaningful for the development of plasma diagnostic.
On-chip 3D confocal optical study of an InGaN/GaN microrod LED in the low excitation regime
Authors: Meier Johanna , Kahl Julius , Avramescu Adrian , Strassburg Martin , Bacher Gerd
Published: July 2021

In this work, we studied p-i-n InGaN/GaN core-shell microrod (μrod) LEDs using confocal microscopy with a spatial resolution below 500 nm in all three dimensions. At low excitation conditions, the devices emit in the red spectral range, while green and blue emissions become more prominent with increasing driving current. 3D photoluminescence (PL) maps demonstrate that the red emission originates from the apex of the tip area, while the green emission stems from the corners between m- and r-planes and the dominant blue emission from the m-plane. Analyzing individual μrods of the LED chip in a closed circuit configuration, a pronounced photocurrent is found for quasi-resonant laser excitation, indicating charge carrier tunneling losses out of the quantum well. This hypothesis is confirmed by applying an external voltage in the forward direction, where a characteristic blueshift of the single μrod PL signal is observed due to a modified band alignment, and a nonlinear increase in the PL intensity proves suppressed tunneling losses.
Focused ion beam fabrication of Janus bimetallic cylinders acting as drift tube Zernike phase plates for electron microscopy
Authors: Rosi Paolo , Gazzadi Gian Carlo , Frabboni Stefano , Grillo Vincenzo , Tavabi Amir H. , Dunin-Borkowski Rafal E. , Pozzi Giulio
Published: July 2021

Modern nanotechnology techniques offer new opportunities for fabricating structures and devices at the micrometer and sub-micrometer level. Here, we use focused ion beam techniques to realize micrometer-sized Janus bimetallic cylinders acting as drift tube devices, which are able to impart a controlled phase shift to an electron wave. The phase shift results from the presence of contact potentials in the cylinders, in a similar manner to the electrostatic Aharonov–Bohm effect in bimetallic wires. We use electron Fraunhofer interference to demonstrate that such bimetallic structures introduce phase shifts that can be tuned to desired values by varying the dimensions of the pillars, in particular their heights. Such devices are promising for electron beam shaping and for the realization of electrostatic Zernike phase plates (i.e., devices that are able to impart a constant phase shift between an unscattered and a scattered electron wave) in electron microscopy, in particular, cryo-electron microscopy.
Solutal convection instability caused by dissolution
Authors: Berhanu Michael , Philippi Julien , Courrech du Pont Sylvain , Derr Julien
Published: July 2021

When a soluble solid body is suddenly put in contact with water, a convection flow can be generated. Once the fluid layer charged into solute is sufficiently dense, this layer becomes unstable under the action of the buoyancy forces. We perform here a linear stability analysis in order to predict the time of appearance of the convection flow, the onset time, and the associated wavelength. As the base state evolves with time due to the solute diffusion, the usual theoretical methods cannot be used. We show that the criterion of marginal instability with a “frozen base state” used for convection in porous media fails for providing the onset parameters in fluid convection. Here, using a modified criterion, i.e., the instability growth rate must be larger than the time evolution of the base state, we find the onset parameters in satisfying agreement with the previous experimental and numerical works. Our results complete our previous numerical work [J. Philippi et al., “Solutal convection induced by dissolution,” Phys. Rev. Fluids 4, 103801 (2019)] in order to determine the conditions for generating a convective flow under the action of dissolution.
Universal alignment of surface and bulk oxygen levels in semiconductors
Authors: Chakrapani Vidhya
Published: July 2021

Oxygen and hydrogen are the two most important impurities in semiconductors because of their ubiquitous presence in growth and device processing environments, and consequently, their incorporation strongly influences electronic and electrical properties. Therefore, a deeper understanding of the interaction of these species with the semiconductor surface and bulk defects is necessary for enabling the development of devices based on them, such as photovoltaic and photocatalytic systems and fuel cells. It is shown here, through the analysis of the reported surface work function values and substitutional bulk O-defect energies, that the surface Fermi level of semiconductors with physisorbed O2 lies universally at approximately −5.1 eV below the vacuum level. Similarly, the results show that the energy of substitutional bulk O-related amphoteric defects incorporated during the crystal growth also has a universal energy of ∼−5.0 eV with respect to the vacuum level for most semiconductors investigated. It is shown that the process of “surface transfer doping” involving an adsorbed water film on the semiconductor surface is likely responsible for the universal alignment of oxygen levels.
Epitaxial thin films of room-temperature ferromagnetic semiconductor based on Fe2TiO5–FeTi2O5 solid solution
Authors: Li H. , Yamahara H. , Tabata H. , Seki M.
Published: July 2021

A series of epitaxial Fe2−xTi1+xO5 (0 ≤ x ≤ 0.7) solid solution thin films was fabricated on SrTiO3 (100) substrates by pulsed laser deposition. A (230)-oriented single phase with an orthorhombic structure was obtained within a narrow growth temperature window (850–900 °C). Both the semiconducting Fe1.5Ti1.5O5 and the insulating Fe1.3Ti1.7O5, as n-type oxides, showed promising thermoelectric properties with giant Seebeck coefficients up to the mV/K level. The electrical conduction in the Fe1.5Ti1.5O5 film obeyed the Arrhenius law at 200–300 K but transitioned to three-dimensional variable range hopping at 120–180 K. Furthermore, at and above room temperature (∼400 K), all the films (x = 0, 0.3, 0.5, and 0.7) exhibited significant ferromagnetic behavior, which was closely dependent on the different ratios of Fe2+, Fe3+, and Ti4+ ions. These results potentially lay a solid foundation for future cost-effective spintronics applications of Fe2−xTi1+xO5 films as tunable ferromagnetic semiconductors.
High-temperature properties and enhanced magnetic properties by magnetic field heat treatment of D022 Mn3−xGa (x = 0, 0.2, and 0.4) alloys
Authors: Liang Dong , Tian Guang , Yun Chao , Zhao Hui , Liu Shunquan , Wang Changsheng , Han Jingzhi , Du Honglin , Xu Qing , Zhang Yan , Yang Jinbo , Yang Wenyun
Published: July 2021

In situ high-temperature XRD and magnetic field heat treatment (MFHT) under a magnetic field of 50 kOe have been used to investigate the structural and magnetic properties of the D022 Mn3−xGa (x = 0, 0.2, and 0.4). It was found that Mn3−xGa compounds maintain ferrimagnetic D022 phase in the temperature range of 300–700 K, and their magnetic properties were remarkably improved through MFHT. The saturation magnetization (Ms) of Mn3.0Ga at 300 K increased by 37% from 18.3 to 25.0 emu/g after MFHT. All Mn3-xGa samples showed superior thermal stability in magnetization from 300 to 500 K, and they still retained excellent magnetic properties at a temperature of up to 700 K. The magnetization of Mn3.0Ga and Mn2.8Ga showed a positive temperature coefficient from 300 to 400 K. Even at 700 K, Ms and Hc of 24.3 emu/g and 4.5 kOe were retained in Mn2.8Ga, which is excellent for high-temperature applications. In addition, the coercivity mechanism of Mn3−xGa at 700 K was illustrated by minor hysteresis loops measurement, and it was found that the coercivity mechanism of Mn3−xGa at 700 K was dominated by the pinning mechanism.
Effect of fly ash on the self-healing capability of cementitious materials with crystalline admixture under different conditions
Authors: Wang Xi , Qiao Hao , Zhang Ziwei , Tang Shiying , Liu Shengjun , Niu Mengdie , Li Guoxin
Published: July 2021

The self-healing capability of cracks plays an important role in improving the durability of concrete. This study investigated the the self-healing capability of mortar with crystalline admixture and fly ash under three conditions. The compressive strength, water absorption, and surface crack pattern were used to evaluate self-healing capability of mortar, and the composition of the healing products was analyzed by x-ray diffraction and scanning electron microscopy. The results indicated that the crystalline admixture could improve the self-healing capability of cementitious materials but caused a negative effect if adding too great an amount of fly ash (≥20%). The specimen that was immersed in water showed favorable self-healing capability of cracks. The healing products in cracks are mainly composed of CaCO3.
Dynamic characteristics of a prestressed micro-diaphragm in a fluid subjected to distributed mass loading
Authors: Ma Shujun , Yang Kang , Wang Shiliang , Liu Hui , Zhou Xu , Li Muxin
Published: July 2021

This paper studies the vibrational behaviors of a distributive mass-loaded microscale circular diaphragm submerged in a fluid. The vibration of the diaphragm involving loadings simultaneously induced by an acoustic field and the adhesion of distributive mass has been investigated. Two different types of adsorbates, namely, in the form of discrete particles (mass only) and a uniform layer (mass and rigidity), are considered and compared. Moreover, the pre-existing stress in the diaphragm has also been taken into consideration. Based on Lamb's hypotheses of the fluid-loaded structure in conjunction with the Rayleigh–Ritz theorem, an analytical solution for the dynamic characteristics of the coupling system, including the resonant frequency, mode shape, and the quality factor, is developed. The results have been compared with those of the finite element simulations, and a good agreement has been obtained. The results reveal that the adsorbate properties contribute differently to the dynamic response of the micro-diaphragm in the fluid, and the contribution may be intervened by tuning the pre-stress. The theoretical model and novel analytical solution are of interest in the design of micro-diaphragm-based biosensing devices.
High-efficient and high-accurate integrated division-of-time polarimeter
Authors: Liu Wei , Liao Jiawen , Yu Yu , Zhang Xinliang
Published: July 2021

The characterization of the state of polarization is of great importance in broad applications, such as microscopy, communications, astronomy, and remote sensing. In this Letter, we propose and demonstrate a novel integrated division-of-time polarimeter (DOTP) based on a Mach–Zehnder interferometer and two photodetectors (PDs). The proposed DOTP achieves improved measuring efficiency and accuracy by measuring a pair of orthogonal polarization states simultaneously. The analysis matrix, which is used to recover the Stokes vector, is elaborately optimized to reduce the influence of the PD noise. Compared to the conventionally designed DOTP, the measuring efficiency is improved by 33% and the equally weighted variance, a figure of merit used to characterize the total variance of the Stokes vector, is also reduced by 33%. The performance of the proposed device is experimentally characterized by comparing with a commercial product. Furthermore, a method based on the least-squares method and singular value decomposition is adopted to quantize the deviation between the ideal optimal analysis matrix and the practical one.
Outer billiards outside regular polygons: tame case
Authors: Rukhovich Philip Dmitrievich
Published: July 2021

We consider the periodicity problem, that is, the existence of an aperiodic point and
fullness of measure of the set of periodic points for outer billiards outside regular $n$-gons.
The lattice cases
$n=3,4,6$ are trivial: no aperiodic points exist and the set of periodic points is of full measure.
The cases $n=5,10,8,12$ (and only these cases) are regarded as tame. The periodicity
problems were solved for $n=5$ in a breakthrough paper by Tabachnikov, who pioneered a renormalization-scheme method for studying the arising self-similar structures.
The case $n=10$ is similar to $n=5$ and was studied earlier by the present author. The present
paper is devoted to the remaining cases $n=8,12$. We establish the existence of an aperiodic orbit
in outer billiards outside regular octagons and dodecagons and prove that almost all trajectories
of these outer billiards are periodic. In the regular dodecagon case we give a rigorous
computer-assisted proof. We establish equivalence between the outer billiards outside
a regular $n$-gon and a regular $n/2$-gon, where $n$ is even and $n/2$ is odd.
Our investigation is based on Tabachnikov's renormalization scheme.
Microalgal blooms in the skeletons of bleached corals during the 2020 bleaching event on Heron Island, Australia
Authors: Fordyce A. J. , Ainsworth T. D. , Page C. E. , Bergman J. L. , Lantz C. A. , Leggat W.
Published: July 2021

Climate change is increasing the frequency of marine heatwaves around the world, causing widespread degradation of coral reefs. Endolithic microalgae inhabiting the coral skeleton have been highlighted as potentially important mediators of the consequences of heatwaves on coral reefs. These microalgae often bloom during heat stress due to greater light availability, theoretically delaying coral starvation by providing photoassimilates. However, these microalgae also dissolve coral skeletons at an accelerated rate during marine heatwaves, affecting the structural complexity of the reef. Despite their ecological role, no studies have examined endolithic algal blooms during a natural bleaching event. We quantified blooms of endolithic microalgae in the skeletons of lagoon corals bleaching on Heron Island in the austral summer of 2020. At the peak of heat stress, 20–30% of bleached corals across 9 genera at 3 sites had blooms. They were predominantly seen in branching Acropora spp. (37.8, 65.7 and 66.7% at three sites), which are primary reef builders at Heron Island. At the end of the bleaching event, the overall prevalence varied between 5 and 42%, and nearly all blooms were observed in acroporids. The relative high frequency of these blooms highlights the ongoing need to understand the role of these microbes during coral bleaching events.
Moral distress in community health nursing practice
Authors: Guzys Diana , Tori Kathleen , Mather Carey
Published: July 2021

Contemporary sociopolitical circumstance impedes the delivery of primary health care in keeping with its underlying philosophy and tenets. Skills to negotiate the maintenance of best practice and quality care in an evolving practice environment are fundamental to nursing. Nurse education needs to incorporate the ideals of best practice ideology to ensure that all are prepared to negotiate the realities of nursing practice. In this discussion paper the experience of moral distress by community health nurses is used to illustrate why skills in political advocacy and action are equally essential as clinical skills in nurse education and professional practice.
Citizen monitoring promotes informed and inclusive forest governance in Liberia
Authors: Christensen Darin , Hartman Alexandra C. , Samii Cyrus
Published: July 2021

Significance

Global forest conservation depends on decisions made in the rural, often poor communities that live next to the Earth’s remaining forests. These decisions often result in rapid deforestation. Coordinated with randomized experiments in five other countries, we evaluate a program that recruits and deploys citizens to monitor communal forestland in Liberia. By informing and mobilizing citizens, the program aims to address two potential governance problems: overuse due to common pool dilemmas and unaccountable leaders profiting from unwanted agribusiness or logging operations. We show that citizen monitoring corrects misconceptions about forest use, broadens participation in rule-making, increases accountability for chiefs (local leaders), and increases material benefits for households. We do not observe a decline in forest use.
The impact of childhood lead exposure on adult personality: Evidence from the United States, Europe, and a large-scale natural experiment
Authors: Schwaba Ted , Bleidorn Wiebke , Hopwood Christopher J. , Gebauer Jochen E. , Rentfrow P. Jason , Potter Jeff , Gosling Samuel D.
Published: July 2021

Significance

Childhood lead exposure causes lifelong psychological problems, which may be more extensive than previously thought. In a sample of over 1.5 million people, we found that US and European residents who grew up in areas with higher levels of atmospheric lead had less adaptive personality profiles in adulthood (lower conscientiousness, lower agreeableness, and higher neuroticism), even when accounting for socioeconomic status. These effects were driven by participants ages 20 to 39. In a natural experiment, reductions of leaded gasoline in the United States following the 1970 Clean Air Act corresponded with increases in psychologically healthy personality traits. These results suggest that even low-level lead exposure may adversely impact personality traits, harming the well-being, longevity, and economic prospects of millions of people.
The effects of footwear midsole longitudinal bending stiffness on running economy and ground contact biomechanics: A systematic review and meta‐analysis
Authors: Rodrigo‐Carranza Víctor , González‐Mohíno Fernando , Santos‐Concejero Jordan , González‐Ravé José María
Published: July 2021

This study aimed to address the effects of increased longitudinal bending stiffness (LBS) on running economy (RE) and running biomechanics. A systematic search on four electronic databases (Pubmed, WOS, Medline and Scopus) was conducted on 26 May 2021. Twelve studies met the inclusion criteria and were included. Standardised mean difference with 95% confidence intervals (CI) between footwear with increased LBS vs. non‐increased LBS conditions and effect sizes were calculated. To assess the potential effects of moderator variables (type and length plate, increased LBS, shoe mass and running speed) on the main outcome variable (i.e. RE), subgroup analyses were performed. Increased LBS improved RE (SMD = −0.43 [95% CI −0.58, −0.28], Z = 5.60, p < 0.001) compared to non‐increased LBS. Significant increases of stride length (SMD = 0.29 [95% CI 0.10, 0.49], Z = 2.93, p = 0.003) and contact time (SMD = 0.17 [95% CI 0.03, 0.31], Z = 2.32, p = 0.02) were found when LBS was increased. RE improved to a greater degree at higher running speeds with footwear with increased LBS. RE improved 3.45% with curve plate compared to no‐plate condition without improvements with flat plate shoes. When shoe mass was matched between footwear with increased LBS vs. non‐increased LBS conditions, RE improved (3.15%). However, when shoe mass was not controlled (experimental condition with ∼35 grams extra), a significant small improvement was found. These RE improvements appear along with an increase of stride length and contact time. Shoe mass, type of plate (flat or curve) and running speed should be taken into consideration when designing a shoe aimed at improving long‐distance running performance.
Forensic Profiling of Non-Volatile Organic Compounds in Soil using Ultra-Performance Liquid Chromatography: A Pilot Study
Authors: Lee Loong Chuen , Ishak Ab Aziz , Nai Eyan Ameeta A/P , Zakaria Anas Fahmi , Kharudin Nurul Syahiera , Noor Nor Azman Mohd
Published: July 2021

Soil is of particular interest to the forensic community because it can be used as valuable associative evidence to link a suspect to a victim or a crime scene. Liquid chromatography is a powerful analytical tool for organic compound analysis. Recently, high-performance liquid chromatography (HPLC) has proven to be an efficient method for forensic soil analysis, especially in discriminating soils from proximity locations. However, ultra-performance liquid chromatography (UPLC), which is much more sensitive than HPLC, has never been explored in this context. This study proposed a UPLC method for profiling non-volatile organic compounds in three Malaysian soils (red, brown and yellowish-brown soils). The three soils were analysed separately to assess the effects of individual chromatographic parameters: (a) elution programme (isocratic vs. two gradient programmes); (b) flow rate (0.1 vs. 0.2 mL/min); (c) extraction solvent (acetonitrile vs. methanol) and (d) detection wavelength (230 vs. 254 nm). The injection volume and total run time were set to 5 µL and 35 min, respectively. Consequently, each soil sample gave 24 different chromatograms. Results showed that the most desirable chromatographic parameters were (a) isocratic elution; (b) flow rate at 0.2 mL/min and (c) acetonitrile extraction solvent. The proposed UPLC system is expected to be a feasible method for profiling non-volatile organic compounds in soil, and is more chemical-efficient than a comparable HPLC system. Key PointsUPLC is a chemical-efficient analytical method for profiling non-volatile organic compounds in soil.Mobile phase rich in acetonitrile promotes separation of non-volatile organic compounds in soil.Isocratic elution is more desirable than gradient elution in producing a high-quality chromatogram.
Self-similar expansion of a plasmoid supplied by pellet ablation
Authors: Arnold Alistair M , Aleynikov Pavel , Helander Per
Published: July 2021

Cryogenic pellet injection is an important means of refuelling and terminating fusion plasmas, with fuel pellets exhibiting a range of phenomena beneficial to confinement and the energy balance between ions and electrons. In this investigation we consider the self-similar expansion along magnetic field lines of the plasmoid produced by a small pellet. In particular, we consider the case when the expansion timescale is comparable to the time taken for the pellet gas cloud to cross a field line. It is shown that plasmoid ions acquire a significant fraction of the energy that is transferred to plasmoid electrons via collisions with the ambient plasma. It is found that the expansion is insensitive to the profile of the gas cloud and details of the ionisation of the gas—the plasma flux emerging from the gas cloud is the only quantity that affects the expansion.
Effects of Morphological and Structural Properties of Zinc Oxide Nanostructures on the Performance of an Ultraviolet Detector
Authors: Sutanto Yohan , Roza Liszulfah , Putri Nur Ajrina , Fauzia Vivi
Published: July 2021

This study proposed cost-effective metal-oxide photoconductors using a glass substrate; three different ZnO nanostructures were used as sensing materials. ZnO-sensing materials were fabricated in thin films and one-dimensional nanorods (NRs). ZnO thin films were fabricated using the ultrasonic spray pyrolysis method, while ZnO nanorods were fabricated by employing the hydrothermal technique. The results reveal that ZnO thin film-sensing materials exhibit higher performance than nanorods. The results also show that ZnO thin films have the highest performance (responsivity: 8884 A/W; detectivity: 6.7 x 1012Jones; sensitivity: 403%; rise time: 12 s; recovery time: 34 s). The better performance of the ZnO thin films’ UV detector to the higher ratio of photocurrent to dark current. ZnO NRs-based devices have a higher dark current, possibly because of the large number of crystal defects found in ZnO NRs, as indicated by defective emissions in the photoluminescence spectra.
Antimicrobial activity analysis of Piper betle Linn leaves extract from Nganjuk, Sidoarjo and Batu against Escherichia coli, Salmonella sp., Staphylococcus aureus and Pseudomonas aeruginosa
Authors: Ermawati FU , Sari R. , Putri NP , Rohmawati L , Kusumawati DH , Munasir  , Supardi ZAI
Published: July 2021

The outbreak of the COVID-19 virus in Indonesia since early March 2020 has caused many casualties. To prevent this, everyone must wear a mask, wash their hands and maintain social distancing. Hand washing can be done with a hand sanitizer that contains up to 70% alcohol so that it has the potential to kill bacteria and the COVID-19 virus. However, alcohol has some disadvantages such as being flammable, leading to dry skin and removing the protective film of skin. For this reason, the formulation of an alcohol-free antiseptic liquid such as green leaves of Piper betle Linn can be an alternative solution because it contains various substances that are useful for human health, including essential oils, carvacrol and tannins which function as antiseptics, antiviral and antimicrobial. This study reports the antimicrobial activity of Piper betle Linn leaves extract from three districts: Nganjuk, Sidoarjo and Batu with a concentration of 50% to inhibit the growth of Escherichia coli, Salmonella sp., Staphylococcus aureus and Pseudomonas aeruginosa. The aim was to compare the ability of the three extracts in inhibiting the growth of each bacterium. The extracts were prepared by maceration method using 96% ethanol. The evaluation was performed by agar diffusion method based on the Indonesian Pharmacopeia IV. Streptomycin 100 ppm, 50 μL was used as the positive control. It was investigated that the growth inhibitory responses of the three extracts to the four bacteria are comparable to the response of Streptomycin and are classified as moderate.
Synthesize of rGO from coal (sub-bituminous) as a counter-electrode on dye-sensitized solar cells
Authors: Arsyad Waode Sukmawati , Pranata Yudi , Variani Viska Inda , Usman Ida , Aba La , Agusu La
Published: July 2021

In the quest for a replacement for platinum as catalytic material in DSSC’s counter electrode (CE), this research aims to extract reduced graphene oxide (rGO) from coal. The coal used was a sub-bituminous type originated from Kolaka Timur, which extracted to rGO with modified Hummer methods. The resulting rGO was characterized by Energy Dispersive X-Ray Spectroscopy (EDS), FTIR, XRD, and LCR meter, to investigate the atomic composition, chemical bonds, crystal structure, and conductivity. For CE fabrication, rGO was mixed with ethyl cellulose (EC) and dissolved in terpineol with a ratio of 100:10, 100:20, 100:50, 100:70, and 100:100 in weight. The structure of the fabricated solar cell was FTO/TiO2/Dye/Electrolyte/rGO/FTO. From the EDS result, we identified the elements of C and O that was the main constituent for rGO, with the highest C/O ratio was 0.81. From FTIR spectra, it was found that the rGO still contain impurities originated from quartz, kaolinite and illite mineral. From rGO 4 XRD characterization, the rGO peak was identified at a 2θ position of 23.9° with a crystallite size of 47.5 nm. The obtained conductivity for rGO in this research was 2.18 x 10−1 S/cm. From photovoltaic characteristic measurement, the highest overall conversion efficiency was 0.046% for rGO:EC of 100:70. The efficiency of the DSSC cells in this research was noticeably low due to the quality of the resulting rGO that was marked by small C/O ratio and the existence of impurity minerals as indicated in the FTIR and XRD data.
Local structure and electronic structure of LiFePO4 as a cathode for lithium-ion batteries
Authors: Astuti Fahmi , Maghfirohtuzzoimah Vera Laviara , Intifadhah Sahara Hamas , Az-Zahra Pelangi , Arifin Rizal , Klysubun Wantana , Zainuri Mochamad , Darminto
Published: July 2021

The local and electronic structure are significant to determine the performance of electrodes in lithium-ion batteries (LIB). Here we report the local structure of LiFePO4 as a cathode of LIB studied by Fe K-edge on X-ray absorption spectroscopy (XAS). The mixture of oxidation state of Fe ion (Fe2+/Fe3+) and the nearest neighbor of Fe atom were reported in this study. Furthermore, the preliminary study of electronic structure shown by the calculated density of states in antiferromagnetic spin configurations exhibited the prominent role of on-site Coulomb interactions in LiFePO4 material.
Study of Electronic and Magnetic Properties of Single Layered Graphene with Vacancy and (-OH) Adsorption by Density Functional Theory Calculation
Authors: Jannah Zahrotul , Asih Retno , Arifin Rizal , Darminto
Published: July 2021

Graphene is one of the most popular two-dimensional materials. However, a zero bandgap character of graphene restricts some nanoelectronics uses. Thus a defect or functional group is generally introduced to create magnetism in graphene Here, we study electronic and magnetic properties of single-layered graphene having a vacancy and hydroxide (-OH) adsorption. The calculation is performed by employing the spin-polarized density functional theory (DFT) method using the Quantum Espresso package. Modeled systems used in the calculation are the 4x4x1 graphene supercell (G), single vacancy graphene (SVG), and SVG with OH adsorption (G-OH). The band gaps calculated from SVG obtained 1.2 eV (spin-up) and 0.7 eV (spin-down), and G-OH obtained 0.8 eV (spin-up) and 1.2 eV (spin-down) after optimized structure. Moreover, the magnetic moment is estimated to be 0.69 μ

B
per cell and 1.00 μ

B
per cell for SVG and G-OH, respectively. The result shows that the defect influences electronic and magnetic properties on graphene. The results of this analysis can be used for future research of graphene applications.
Force-displacement analysis of PMMA/zircon composites using dynamic mechanical analyzer (DMA)
Authors: Hilmi A R , Dona R , Purnamasari N D , Wulandari W , Fauziyah N A , Pratapa S
Published: July 2021

In the study, poly(methyl methacrylate) (PMMA)/zircon (ZrSiO4) composites were successfully prepared using the liquid method at different compositions of 1, 2.5, and 5 wt% of zircon. The zircon filler was processed from a natural, local zircon sand and was processed via a top-down method using wet ball-milling for 5 and 15 h as well as annealing at temperature of 200 °C for 1 h. The force-displacement curves of the composites have been acquired using a DMA (dynamic mechanical analyzer) technique in tensile mode. XRD (x-ray diffraction) data of the composites were collected and analyzed in order to examine the present phases and used as the evidence of the formation of the composites. Furthermore, MAUD software was used to estimate the crystallite size of the filler. Results indicated that zircon crystallite size for 15 h wet ball-milling was smaller than that of 5 h. Furthermore, the maximum DMA force (also representing stress) for the composite with smaller filler was generally higher than that of 5 h, ca. by 2.5 times. In addition, in general, the composites exhibited an increasing slope of force-displacement curve with increasing amount of filler.
ANC Gen1: BBTA3 - BPPT 1st Prototype of Active Noise Control for Vehicle Cabin Noise
Authors: Atmojo A Y , Masfuri Z , Sabrina M , Basuki A , Feriadi Y , Suwarjono  , Sugianto
Published: July 2021

Presently, value of passenger vehicle shifted from more than conventional transporting tools. Its comfort become important consideration beside its functionality, and no exception for its cabin noise also. Vendors and engineers have given their effort in minimizing vehicle cabin noise within many methods for many years. One of them is Active Noise Control (ANC) method by giving opposite signal called anti-noise that interfere and cancel each other with the noise itself. BBTA3 - BPPT have performed development of ANC system since last year, especially for medium passenger vehicle. Implementing Least Mean Square (LMS) algorithm and broadband feedforward strategy, least significance but a promising result have been achieved by the 1st prototype that have been tested in mid of 2020. Around 1 dB of best average decrement of cabin noise have been noted for its lab-scaled testing, and less than 0.5 dB for its road test result. Comprehensive approaches have been recommended for next step of development, including algorithm enhancement, hardware specification improvement, and spin-off research about acoustic-noise energy harvesting.
Optical and magneto-optical properties of Fe
x
Ag
x
superlattices: first-principles study
Authors: Arifin M , Nakamura K
Published: July 2021

Optical and magneto-optical properties of Fe
x
Ag
x
superlattices with thickness (x) of 1, 2, and 3 atomic-layers were investigated from first-principles calculations by using full-potential linearized augmented plane wave method and Kubo formula. Based on the calculated optical conductivity tensors, the characteristic features in dielectric functions, refractive indexes, absorptions, electron loss functions, and magneto-optical constants in the Fe
x
Ag
x
superlattices were systematically elucidated. We found that the optical properties can be controlled by tuning the hybridization of d-orbitals between Fe and Ag due to changes in the thickness of superlattices.
Impact of climate variability on skipjack tuna (Katsuwonus pelamis) catches in the Indonesian Fisheries Management Area (FMA) 715
Authors: Sepri  , Hartoko A , Suradi WS , Ghofar A
Published: July 2021

Marine and fisheries resources have trans-boundary nature and have great potential to be affected by global climate change. Tuna is one of the main export commodities from Indonesia. Patterns of fish life can not be separated from the existence of various environmental conditions. Fluctuations in environmental conditions have many influences on the seasonal migration period and the presence of fish in one place. This study aimed to determine the variability in peak season of tuna fishing to regional climate change, El Nino and La Nina, with the aim to optimize the utilization of Skipjack tuna. A descriptive qualitative study was conducted to investigate the direct correlation between Skipjack tuna catches during 2015 - 2019 and regional climate changes that occurred in those periods, i.e., El Nino (2015-2019) and La Nina (2015-2019). Sampling and measurement times were performed at the end of the East season, which was from September to December 2019. The results of this study show that regional climate change affected inter-monthly variation of the peak seasons of Skipjack fishing in the fisheries management (FMA) 715 area. During El Nino, FMA 715 was an ideal place for Skipjack tuna fishing. The peak fishing season was in October for the period from September to November. The regional climate change triggered from the Pacific Ocean caused the unsuitable water conditions in the FMA 715 for Skipjack tuna fishing. Variability of climate changes triggered by La Nina in the Pacific Ocean did not provide a favorable environment for fish migration to the FMA 715 waters.
Palm fiber as potential material for FADs: durability enhancement and increasing fish catching for small scale fisheries
Authors: Hasaruddin H , Thahir M A , Yusfiandayani R , Baskoro M S , Jaya I
Published: July 2021

Fish aggregating devices (FADs) have brought impact on the fish catching productivity and preciseness of fishing ground. Traditional fisherman is using coconut frond and areca frond for shallow water FADs and it have been increasing cost maintenance of FADs, due to durability of natural attractor like coconut frond and areca frond tend to lower. Therefore, the research aims to determine the influence of different natural attractors of the FADs (i.e., areca frond, coconut frond and palm fiber) to impact the fish catching around the shallow water FADs. Pyramid model was used for attractors of FADs. Data were collected by experimental method, i.e., experimental fishing every two weeks until the fronds (attractors) totally rotted using hand lines (January-May 2019). The location of research is Nagan Raya Waters, Aceh Province (Hindia Ocean). One-way analysis of variance (ANOVA) was conducted to assess differences in the treatment value, namely natural attractors in the FADs for the fish catching number (significant level at 95%). The results showed that the different of natural attractors of the FADs were affected to fish catching around the FADs. Meanwhile, palm fiber attractor is better than to aggregate of fish around FADs, but these has not given significantly different for total catch of fish (p>0.05). Therefore, to maximize fish catch around shallow water FADs and to minimize of maintenance cost for FAD are suggested to using palm fiber attractors. This finding is very important to help traditional FADs fishery in maximizing production of fish and to increasing profit of small scale fisheries.