bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of seeding density on the growth of diamond films by hot-filament chemical vapor deposition from sparse to dense range
Authors: K. C. Anupam , Saha Rony , Anderson Jonathan , Ayala Anival , Engdahl Christopher , Piner Edwin L. , Holtz Mark W.
Published: December 2021

A systematic study is reported on the effects of nano-diamond seeding density on the growth, quality, and morphology of diamond films. A process is described to examine nano-diamond seeding densities 4 × 108, 8 × 1010, and 2 × 1012 cm−2 on silicon wafers. The diamond film is grown using hot-filament chemical vapor deposition with CH4/H2/O2 feed gases and varying growth time to determine properties at coalescence and as thickness increases. Polycrystalline morphology is examined by scanning electron and atomic force microscopy. Both vertical and lateral growth rates are found to be higher for sparse seeding prior to coalescence. Following coalescence, the growth rate is similar for all densities. The development of polycrystals is found to be influenced by the initial growth with smaller mean lateral size at higher seeding density and reduced surface roughness that also improves with thickness to reach ≲90 nm at a thickness of 6.4 μm. The crystal quality is examined by micro-Raman spectroscopy from the sample surfaces and line images from cross sections. Narrowing of the diamond phonon peak shows material quality to improve with the thickness, at a given seed density, and as density increases. Concomitant improvements are seen from the relative intensity of the diamond phonon and Raman bands from non-diamond carbon. Cross-section micro-Raman results suggest improved diamond film quality and crystallinity near the substrate interface as well as at the growth surface for the film grown with 2 × 1012 cm−2 seed density compared to 4 × 108 and 8 × 1010 cm−2. X-ray photoelectron spectroscopy confirms these trends at the diamond surface.
Large stress-induced anisotropy in soft magnetic films for synthetic spin valves
Authors: Chang H. W. , Yuan F. T. , Lin D. Y. , Tseng D. H. , Chang W. C. , Chen Y. S. , Lin J. G.
Published: December 2021

We obtain a large in-plane magnetic uniaxial anisotropy in the soft magnetic Fe60Co20B20 (FeCoB) thin films prepared by rotational sputtering. The anisotropy field (Ha) of 75 to 175 Oe was found in the films with wide ranged thickness from 2.5 to 100 nm, which was attributed to the magnetoelastic energy in association with anisotropic tensile stress. This stress-induced anisotropy has outstanding thermal stability that survives up to 350 °C in the annealing process. The similar large uniaxial anisotropy can be realized in other soft magnetic thin films, such as Fe, Co, Ni, FeCo, and NiFe, with the same synthesis technique. The anisotropic FeCoB film was used as a free layer in a synthetic spin valve. A linear resistance change against external field with a range wider than ±100 Oe together with a significantly reduced coercivity of ∼1.1 Oe (∼8.5 Oe in the case with isotropic free layer) was observed in the transfer curve. The results of this work not only confirm the feasibility of films with large stress-induced magnetic anisotropy as a functional layer in spin-valve devices but also demonstrate a simple synthesis route to induce the magnetic anisotropy, which provides an additional control parameter for the spintronic device design.
Piezoelectric-magnetic behavior of ferroelectrets coated with magnetic layer
Authors: Altafim R. A. P. , Assagra Y. A. O. , Altafim R. A. C. , Carmo J. P. , Palitó T. T. C. , Santos A. M. , Rychkov D.
Published: December 2021

Electrically charged porous electret films, reported as ferroelectrets or piezoelectrets, have drawn the attention of researchers due to their high piezoelectric activity, low density, and flexibility. This paper introduces a ferroelectret design for the development of piezoelectric-magnetic responses. Samples are prepared with an additional magnetic layer placed above open tubular channels made from fused electret films, and the piezoelectric direct effect of electrically charged samples is monitored. The results of the measurements show approximately 900 pC N−1 piezoelectric coefficients d33. The piezoelectric-magnetic effect is an electrical response from a mechanical deformation caused by an external magnetic force. The magnetic field pulls the magnetic layer, mechanically deforming the electrically charged tubular structure, which creates a charge compensation to be measured as a charge density variation. A setup especially assembled for measuring the piezoelectric-magnetic response is described together with piezoelectric-magnetic values ranging from 94 up to 275 pC T−1.
Exciton harvesting in quasi-2D perovskite light-emitting diodes with an encapsulated thermally activated delayed fluorescence
Authors: He Xiaoli , Qiu Suyu , Xu Qiang , Wang Run , Jia Yalan , Huang Xinmei , Zhang Yong , Chen Ping , Ban Xinxin , Gao Chunhong
Published: December 2021

The poor exciton harvesting is a key reason for the poor performance of quasi-2D perovskite light-emitting diodes (PeLEDs). Here, an encapsulated thermally activated delayed fluorescence (TADF) is involved to solve this problem by a solution processed doping method. The maximum current efficiency of optimized PeLEDs is 5.32-fold to that of the pristine one. It is found that the energy funneling process, the Förster energy transfer process, and the reverse intersystem crossing process were working together to improve exciton harvesting. Moreover, the quasi-2D perovskite can be protected from water and oxygen due to the surrounded encapsulated TADF emitters.
Highly transparent Cu2O absorbing layer for thin film solar cells
Authors: Shibasaki Soichiro , Honishi Yuya , Nakagawa Naoyuki , Yamazaki Mutsuki , Mizuno Yukitami , Nishida Yasutaka , Sugimoto Kanta , Yamamoto Kazushige
Published: December 2021

Highly transparent Cu2O thin films on transparent conducting oxide on a glass substrate were fabricated using reactive sputtering by carefully controlling the O2 flow. The impurity dependence of transmittance was thoroughly investigated, and the transmittance was found heavily depending on impurities in Cu2O thin films as confirmed by x-ray diffraction analysis. A highly transparent Cu2O thin film was fabricated using precisely impurity-controlled Cu2O thin films. The effects of impurities in a Cu2O thin film on photovoltaic properties were studied. A maximum efficiency of 8.4% was observed in the lowest-impurity Cu2O thin film.
Modulational instability of two obliquely interacting waves with different carrier frequencies
Authors: Chakrabortty Sabyasachi , Debsarma Suma
Published: December 2021

The paper investigates the crossing sea state situation characterized by two obliquely interacting water wave systems having different carrier frequencies in finite depth domain. Nonlinear evolution equations are derived to study the instability properties of two obliquely interacting uniform wave trains for both unidirectional and bidirectional perturbations. It is found that the growth rate of modulational instability increases with the decrease in angle of interaction of the two wave systems and also with the increase in the ratio of the carrier wave numbers of the two wave systems. The growth rate of instability decreases with the increase in water depth, while it increases with the increase in wave steepness of the second wave system.
Temperature dependence of intrinsic critical current in perpendicular easy axis CoFeB/MgO magnetic tunnel junctions
Authors: Takeuchi Yutaro , Enobio Eli Christopher I. , Jinnai Butsurin , Sato Hideo , Fukami Shunsuke , Ohno Hideo
Published: December 2021

Current induced magnetization switching in CoFeB/MgO-based magnetic tunnel junctions (MTJs) with a perpendicular easy axis is studied above room temperature. The intrinsic critical current IC0 of the MTJs decreases with increasing temperature. From a vector-network-analyzer ferromagnetic resonance measurement with a heating system, temperature dependence of magnetic anisotropy and damping constant is evaluated. We find that the reduction of IC0 at elevated temperature is mainly due to a decrease in magnetic anisotropy. A slight increase in the damping constant with temperature rise is also observed, consistent with the mechanism considering electron scattering through the inter-band transition.
Noble-gas compounds: A general procedure of bonding analysis
Authors: Borocci Stefano , Grandinetti Felice , Sanna Nico
Published: December 2021

This paper accounts for a general procedure of bonding analysis that is, expectedly, adequate to describe any type of interaction involving the noble-gas (Ng) atoms. Building on our recently proposed classification of the Ng–X bonds (X = binding partner) [New J. Chem. 44, 15536 (2020)], these contacts are first distinguished into three types, namely, A, B, or C, based on the topology of the electron energy density H(r) and on the shape of its plotted form. Bonds of type B or C are, then, further assigned as B-loose (Bl) or B-tight (Bt) and C-loose (Cl) or C-tight (Ct) depending on the sign that H(r) takes along the Ng–X bond path located from the topological analysis of ρ(r), particularly at around the bond critical point (BCP). Any bond of type A, Bl/Bt, or Cl/Ct is, finally, assayed in terms of contribution of covalency. This is accomplished by studying the maximum, minimum, and average value of H(r) over the volume enclosed by the low-density reduced density gradient (RDG) isosurface associated with the bond (typically, the RDG isosurface including the BCP) and the average ρ(r) over the same volume. The bond assignment is also corroborated by calculating the values of quantitative indices specifically defined for the various types of interactions (A, B, or C). The generality of our taken approach should encourage its wide application to the study of Ng compounds.
An open repository of real-time COVID-19 indicators
Authors: Reinhart Alex , Brooks Logan , Jahja Maria , Rumack Aaron , Tang Jingjing , Agrawal Sumit , Al Saeed Wael , Arnold Taylor , Basu Amartya , Bien Jacob , Cabrera Ángel A. , Chin Andrew , Chua Eu Jing , Clark Brian , Colquhoun Sarah , DeFries Nat , Farrow David C. , Forlizzi Jodi , Grabman Jed , Gratzl Samuel , Green Alden , Haff George , Han Robin , Harwood Kate , Hu Addison J. , Hyde Raphael , Hyun Sangwon , Joshi Ananya , Kim Jimi , Kuznetsov Andrew , La Motte-Kerr Wichada , Lee Yeon Jin , Lee Kenneth , Lipton Zachary C. , Liu Michael X. , Mackey Lester , Mazaitis Kathryn , McDonald Daniel J. , McGuinness Phillip , Narasimhan Balasubramanian , O’Brien Michael P. , Oliveira Natalia L. , Patil Pratik , Perer Adam , Politsch Collin A. , Rajanala Samyak , Rucker Dawn , Scott Chris , Shah Nigam H. , Shankar Vishnu , Sharpnack James , Shemetov Dmitry , Simon Noah , Smith Benjamin Y. , Srivastava Vishakha , Tan Shuyi , Tibshirani Robert , Tuzhilina Elena , Van Nortwick Ana Karina , Ventura Valérie , Wasserman Larry , Weaver Benjamin , Weiss Jeremy C. , Whitman Spencer , Williams Kristin , Rosenfeld Roni , Tibshirani Ryan J.
Published: December 2021

Significance

To study the COVID-19 pandemic, its effects on society, and measures for reducing its spread, researchers need detailed data on the course of the pandemic. Standard public health data streams suffer inconsistent reporting and frequent, unexpected revisions. They also miss other aspects of a population’s behavior that are worthy of consideration. We present an open database of COVID signals in the United States, measured at the county level and updated daily. This includes traditionally reported COVID cases and deaths, and many others: measures of mobility, social distancing, internet search trends, self-reported symptoms, and patterns of COVID-related activity in deidentified medical insurance claims. The database provides all signals in a common, easy-to-use format, empowering both public health research and operational decision-making.
Constructing local cell-specific networks from single-cell data
Authors: Wang Xuran , Choi David , Roeder Kathryn
Published: December 2021

Significance

Understanding gene regulatory networks is a topic of great interest because it can provide insights into cellular development, and identify factors that differ between normal and abnormal cells and phenotypes. Single-cell RNA sequencing provides a unique opportunity to gain understanding at the cellular level, but the technical features of the data create severe challenges when constructing gene networks. We develop a method that successfully skirts these challenges to estimate a cell-specific network for each single cell and cell type. Application of our algorithm to two brain cell samples furthers our understanding of autism spectrum disorder by examining the evolution of gene networks in fetal brain cells and comparing the networks of cells sampled from case and control subjects.
Theta activity paradoxically boosts gamma and ripple frequency sensitivity in prefrontal interneurons
Authors: Merino Ricardo Martins , Leon-Pinzon Carolina , Stühmer Walter , Möck Martin , Staiger Jochen F. , Wolf Fred , Neef Andreas
Published: December 2021

Significance

Rhythmic brain activity is a signature of information processing. Common inhibitory cells, spike-frequency adapting interneurons, are typically thought to only participate in low-frequency rhythms (<10 Hz). However, we found that these cells’ frequency preference can be switched from 2 to 200 Hz. The switch occurs when low-frequency components dominate the interneurons’ input, as is the case during brain states of slow-wave sleep or quiet rest. These interneurons not only increase their sensitivity to input in the 30 to 200 Hz range (gamma and ripples) they do so within a few dozen milliseconds, in phase with the low-frequency input components. Our findings reveal unexpected flexibility in neurons, which could shape theta-gamma cross-frequency coupling, a phenomenon thought to contribute to information routing.
Responses within activities
Authors: Marmorstein Michal , Matalon Nadav
Published: December 2021

Large conversational activities (e.g., storytelling) necessitate a suspension of ordinary turn-taking rules. In the resulting constellation of main speaker and recipient, minimal displays of cooperative recipiency become relevant at particular junctures. We investigate this mechanism by focusing on the Egyptian Arabic particleʔāh‘yeah’ when thus used. We observe that tokens ofʔāhare mobilized by main speakers via the opening of prosodic slots at local pragmatic completion points. The prosodic design of the particle at these points is sensitive to prior talk and displays recipients’ alignment at the structural, action-sequential, and relational levels. This is done through variation of three prosodic features, namely, rhythm-based timing, pitch configuration, and prominence. The measure of alignment proposed byʔāhis implicative for the continuation of the turn. While smooth progression suggests thatʔāhis understood to be sufficiently fitted and aligned, expansions are traceable to a departure from the terms set by prior talk, which can be heard to indicate lesser alignment. We propose to viewʔāhresponse tokens as a subset of positionally sensitive responses to part-of-activity actions that are crucial for the co-accomplishment of a large activity.
Cross-sectional analysis of coping strategies and anxiety and depression levels in a sample of the Andalusian population during the home lockdown caused by the COVID-19 pandemic (Análisis transversal de las estrategias de afrontamiento y los niveles de ansiedad y depresión en una muestra de población andaluza durante el confinamiento domiciliario motivado por la pandemia de la COVID-19)
Authors: Zayas Antonio , Cruces-Montes Serafín J. , Paramio Alberto , Romero-Moreno Antonio , López-Sánchez José-Antonio , Gómez-Carmona Diego , Merchán-Clavellino Ana , Guil Rocío
Published: December 2021

The restrictive measures put into place to control the COVID-19 pandemic in 2020 have prompted the need to study the possible health impacts in the middle term. Deprivation of the fundamental right to mobility results in an increase in affective disorders and the risks that they entail for the population. The goal of this study is to examine anxiety and depression levels during the first national lockdown and to determine the key coping strategies in order to develop health treatment and promotion programmes. The sample, comprised of 485 participants (mean age = 40) from Andalusia, received questionnaires via email between March and June. The results showed that acceptance, active coping and humour were the most effective coping strategies to explain and predict a decrease in anxiety and depression within the context of the home lockdown. Therefore, we recommend that these coping strategies be studied in order to develop programmes that help prevent the psychological consequences of the lockdown.
A multi-system weighted fusion method to improve measurement accuracy of structured light 3D profilometry
Authors: Xing Chao , Huang Junhui , Wang Zhao , Gao Jianmin
Published: December 2021

Improving the accuracy of three-dimensional profile measurement based on binary coded structured light for complex surfaces is a challenge. A new method of weighted fusion using multiple systems is presented to reduce the measurement errors due to the stripe grayscale asymmetry. It is based on the analysis of stripe center deviation related to the surface normal and the directions of incident and reflected rays. First, the stripe center deviation model is established according to the geometric relationship between the stripe center deviation and the incident and reflected angles at any measured point. The influence of each variable on stripe center deviation is analyzed, and three subsystems are formed by a binocular structured light framework to achieve multiple measurements based on the influence regularity. Then, in order to improve the measurement accuracy, different weights are assigned to the measured point in the different subsystems according to the stripe center deviation model and its relationship with the measurement error, and the weighted data from the different subsystems are fused. Experiments are carried out to validate the presented method, and the experimental results demonstrate that it effectively improves the measurement accuracy of complex surfaces. The measurement accuracy is improved by about 27% compared with the conventional method.
Au aerogel for selective CO2 electroreduction to CO: ultrafast preparation with high performance
Authors: Yan Shenglin , Mahyoub Samah A , Lin Jing , Zhang Chunxiao , Hu Qing , Chen Chengzhen , Zhang Fanghua , Cheng Zhenmin
Published: December 2021

Noble metal aerogels (NMAs) have been used in a variety of (photo-)electrocatalytic reactions, but pure Au aerogel (AG) has not been used in CO2 electroreduction to date. To explore the potential application in this direction, AG was prepared to be used as the cathode in CO2 electroreduction to CO. However, the gelation time of NMAs is usually very long, up to several weeks. Here, an excess NaBH4 and turbulence mixing-promoted gelation approach was developed by introducing magnetic stirring as an external force field, which therefore greatly shortened the formation time of Au gels to several seconds. The AG-3 (AG with Au loading of 0.003 g) exhibited a high CO Faradaic efficiency (FE) of 95.6% at an extremely low overpotential of 0.39 V, and over 91% of CO FE was reached in a wide window of −0.4 to −0.7 V versus the reversible hydrogen electrode (RHE). Partial current density in CO was measured to be −19.35 mA cm−2 at −0.8 V versus RHE under 1 atm of CO2. The excellent performance should be ascribed to its porous structure, abundant active sites, and large electrochemical active surface area. It provides a new method for preparation of AG with ultrafast gelation time and large production at room temperature, and the resulting pure AG was for the first time used in the field of CO2 electroreduction.
The role of cell–matrix interactions in connective tissue mechanics
Authors: Muntz Iain , Fenu Michele , van Osch Gerjo J V M , Koenderink Gijsje H
Published: December 2021

Living tissue is able to withstand large stresses in everyday life, yet it also actively adapts to dynamic loads. This remarkable mechanical behaviour emerges from the interplay between living cells and their non-living extracellular environment. Here we review recent insights into the biophysical mechanisms involved in the reciprocal interplay between cells and the extracellular matrix and how this interplay determines tissue mechanics, with a focus on connective tissues. We first describe the roles of the main macromolecular components of the extracellular matrix in regards to tissue mechanics. We then proceed to highlight the main routes via which cells sense and respond to their biochemical and mechanical extracellular environment. Next we introduce the three main routes via which cells can modify their extracellular environment: exertion of contractile forces, secretion and deposition of matrix components, and matrix degradation. Finally we discuss how recent insights in the mechanobiology of cell–matrix interactions are furthering our understanding of the pathophysiology of connective tissue diseases and cancer, and facilitating the design of novel strategies for tissue engineering.
Quantum uncertainty relations of Tsallis relative α entropy coherence based on MUBs
Authors: Zhang Fu-Gang
Published: December 2021

In this paper, we discuss quantum uncertainty relations of Tsallis relative α entropy coherence for a single qubit system based on three mutually unbiased bases. For

α
∈

1

2

,
1

∪
(
1
,
2
]

, the upper and lower bounds of sums of coherence are obtained. However, the above results cannot be verified directly for any

α
∈

0
,

1

2

. Hence, we only consider the special case of

α
=

1

n
+
1

, where n is a positive integer, and we obtain the upper and lower bounds. By comparing the upper and lower bounds, we find that the upper bound is equal to the lower bound for the special

α
=

1

2

, and the differences between the upper and the lower bounds will increase as α increases. Furthermore, we discuss the tendency of the sum of coherence, and find that it has the same tendency with respect to the different θ or φ, which is opposite to the uncertainty relations based on the Rényi entropy and Tsallis entropy.
e
+
e
−
γ production at photon-photon colliders at complete electroweak NLO accuracy *
Authors: Li He-Yi , Zhang Ren-You , Ma Wen-Gan , Jiang Yi , Li Xiao-Zhou
Published: December 2021

We present the NLO electroweak radiative corrections to the

production in γγ collision, which is an ideal channel for calibrating the beam luminosity of a Photon Linear Collider. We analyze the dependence of the total cross section on the beam colliding energy, and then investigate the kinematic distributions of final particles at various initial photon beam polarizations at EW NLO accuracy. The numerical results indicate that the EW relative corrections to the total cross section are non-negligible and become increasingly significant as the increase of the beam colliding energy, even can exceed –10% in the

γγ collision at

. Such EW corrections are very important and should be taken into consideration in precision theoretical and experimental studies at high-energy γγ colliders.
The “Bi-drifting” Subpulses of PSR J0815+0939 Observed with the Five-hundred-meter Aperture Spherical Radio Telescope
Authors: Shang Lun-Hua , Bai Jun-Tao , Dang Shi-Jun , Zhi Qi-Jun
Published: December 2021

We report the “Bi-drifting” subpulses observed in PSR J0815+0939 using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The observation at band from 1050 to 1450 MHz is evenly divided into two bands, i.e., the bands at center frequencies of 1150 and 1350 MHz. The mean pulse profiles and the “Bi-drifting” subpulses at these two bands are investigated. It is found that the pulse profiles at these two frequencies show four emission components, and the peak separations between four emission components decrease with the increase of frequency. In addition, the ratio of peak intensity of each component to the intensity of component IV at 1150 MHz is larger than that at 1350 MHz. We carry out an analysis of the longitude-resolved fluctuation spectrum and two-dimensional fluctuation spectrum for each emission component, and find that the P3 of components I, II and III is about 10.56, 10.57 and 10.59 s at 1150 and 1350 MHz. However, the reliable measurements of P3 of component IV and P2 for these four components were not obtained due to the low signal-to-noise ratio of observation data. The pulse energy distributions at frequencies 1150 and 1350 MHz are presented, and it is found that no nulling phenomenon has been found in this pulsar. With our observation from the FAST, the “Bi-drifting” subpulse phenomenon of PSR J0815+0939 is expanded from 400 to 1350 MHz, which is helpful for the relevant researchers to test and constrain the pulsar emission model, especially the model of “Bi-drifting” subpulse.
Calibrating Photometric Redshift Measurements with the Multi-channel Imager (MCI) of the China Space Station Telescope (CSST)
Authors: Cao Ye , Gong Yan , Zheng Zhen-Ya , Xu Chun
Published: December 2021

The China Space Station Telescope (CSST) photometric survey aims to perform a high spatial resolution (∼0.″15) photometric imaging for the targets that cover a large sky area (∼17,500 deg2) and wide wavelength range (from NUV to NIR). It expects to explore the properties of dark matter, dark energy, and other important cosmological and astronomical areas. In this work, we evaluate whether the filter design of the Multi-channel Imager (MCI), one of the five instruments of the CSST, can provide accurate photometric redshift (photoz) measurements with its nine medium-band filters to meet the relevant scientific objectives. We generate the mock data based on the COSMOS photometric redshift catalog with astrophysical and instrumental effects. The application of upper limit information of low signal-to-noise ratio data is adopted in the estimation of photoz. We investigate the dependency of photoz accuracy on the filter parameters, such as band position and width. We find that the current MCI filter design can achieve good photoz measurements with accuracy σ

z
≃ 0.017 and outlier fraction f
c ≃ 2.2%. It can effectively improve the photoz measurements of the main CSST survey using the Survey Camera to an accuracy σ

z
≃ 0.015 and outlier fraction f
c ≃ 1.5%. This indicates that the original MCI filters are proper for the photoz calibration.
Neural tracking to go: auditory attention decoding and saliency detection with mobile EEG
Authors: Straetmans L , Holtze B , Debener S , Jaeger M , Mirkovic B
Published: December 2021

Objective. Neuro-steered assistive technologies have been suggested to offer a major advancement in future devices like neuro-steered hearing aids. Auditory attention decoding (AAD) methods would in that case allow for identification of an attended speaker within complex auditory environments, exclusively from neural data. Decoding the attended speaker using neural information has so far only been done in controlled laboratory settings. Yet, it is known that ever-present factors like distraction and movement are reflected in the neural signal parameters related to attention. Approach. Thus, in the current study we applied a two-competing speaker paradigm to investigate performance of a commonly applied electroencephalography-based AAD model outside of the laboratory during leisure walking and distraction. Unique environmental sounds were added to the auditory scene and served as distractor events. Main results. The current study shows, for the first time, that the attended speaker can be accurately decoded during natural movement. At a temporal resolution of as short as 5 s and without artifact attenuation, decoding was found to be significantly above chance level. Further, as hypothesized, we found a decrease in attention to the to-be-attended and the to-be-ignored speech stream after the occurrence of a salient event. Additionally, we demonstrate that it is possible to predict neural correlates of distraction with a computational model of auditory saliency based on acoustic features. Significance. Taken together, our study shows that auditory attention tracking outside of the laboratory in ecologically valid conditions is feasible and a step towards the development of future neural-steered hearing aids.
Implementation of planar 3D hydraulic fracture model in rock with layered compressive stress
Authors: Lapin V
Published: December 2021

Plane 3D model of hydraulic fracture propagation is implemented. Fluid flow inside the fracture, leak-of, rock deformation and breaking are taken into account. Asymptotic solution for tip of semi-infinite plane fracture is used to set boundary conditions for fluid flow problem and to calculate fracture front propagation velocity. Elastic and fluid flow equations are united in one system of nonlinear equations and solved simultaneously by Newton method with analytically calculated Jacoby matrix. The implemented model may be used as a start point for testing various methods of solution of “hydrodynamic-elasticity” problem and improving their convergence speed. Also model can be used for developed hydraulic fracture simulation.
Application of various ice accretion simulation approaches in the LOGOS software package
Authors: Galanov N G , Sarazov A V , Zhuchkov R N , Kozelkov A S
Published: December 2021

This paper presents results of the ice accretion simulations by the techniques implemented in the LOGOS-Aero module of the LOGOS software package. The results of the Eulerian and the Lagrangian ice accretion simulations are reported for NACA verification problems, which are used to test the software package Lewice. The approaches implemented in the LOGOS-Aero enable simulations of the aircraft icing conditions and the predictions of the shapes and locations of ice deposits on computational models.
Analysis of aerosol pollution processes in the vicinity of the Irkutsk aluminum plant
Authors: Raputa V F , Grebenshchikova V I , Lezhenin A A , Yaroslavtseva T V , Amikishieva R A
Published: December 2021

The issues of assessing the pollution fields in the vicinity of industrial enterprises are discussed according to the monitoring studies of the snow cover. The formulations of problems of low-parameter reconstruction of concentration fields are considered on the basis of model descriptions of the processes of transport of impurities in the surface layer of the atmosphere. With regard to the Irkutsk aluminum plant, the results of studies of the pollution of its surroundings with aluminum are presented. Using the data of route observations, a numerical reconstruction of the fluoride content in the snow cover was carried out. The quality control of the results obtained is carried out by comparing the measured and calculated concentrations of impurities at the control points of observation.
Sensitivity of functionals in variational data assimilation for a sea thermodynamics model
Authors: Shutyaev V P , Parmuzin E I , Yu Gejadze I
Published: December 2021

The sensitivity of functionals of the optimal solution to a variational data assimilation problem for the sea thermodynamics model is studied. The variational data assimilation problem is formulated as an optimal control problem to find the initial state and the boundary condition. The sensitivity of the response functions as functionals of the optimal solution with respect to the observation data is determined by the gradient of the response function and reduces to the solution of a non-standard problem being a coupled system of direct and adjoint equations with mutually dependent initial and boundary values. The algorithm to compute the gradient of the response function is presented, based on the Hessian of the original cost functional. The sensitivity analysis of the response function with respect to errors of observation data is carried out. Numerical examples are presented for the Black Sea thermodynamics model.
Studying the interaction of a reservoir with an ideal compressible fluid with an elastic half-space
Authors: Telyatnikov I S , Pavlova A V , Rubtsov S E
Published: December 2021

We solve in a flat formulation the problem of harmonic oscillations for a basin with an ideal compressible fluid on an elastic half-space exposed to a localized surface vibration load. The problem reduces to an integral equation (IE) of the first kind for the amplitude of the contact hydrodynamic pressure with a kernel that depends on the difference and the sum of arguments. The IE was solved by the factorization method. A semi-analytical method is presented for determining the main parameters of the contact interaction in hydroelastic systems «liquid-soil» taking into account the effect of natural and man-made vibration loads on them. This makes it possible to identify the conditions for the occurrence of dynamic modes that are dangerous for the construction integrity and to estimate their frequencies range depending on defining characteristics of the system.
Emergence of optimal disturbances in a stratified turbulent shear flow under the stochastic forcing
Authors: Zasko G V , Perezhogin P A , Glazunov A V , Mortikov E V , Nechepurenko Y M
Published: December 2021

Large-scale inclined organized structures in stably stratified turbulent shear flows were revealed in the numerical simulation and indirectly confirmed by the field measurements in the stable atmospheric boundary layer. Spatial scales and forms of these structures coincide with those of the optimal disturbances of a simplified linear model. In this paper, we clarify the relation between the organized structures and the optimal disturbances, analyzing a time series of turbulent fields obtained by the RANS model with eddy viscosity/diffusivity and stochastic forcing generating the small-scale turbulence.
Formalization of target invariants and designing an adaptive control system for the model of anaerobic biological wastewater treatment
Authors: Fomenkova A A , Klucharev A A , Kolesnikova S I
Published: December 2021

A model of a two-step anaerobic fermentation in a bioreactor-mixer, whose mathematical description is a system of nonlinear mathematical equations, is discussed. The purpose is to design an algorithm of an energy-saving control relying on the principles of nonlinear adaptation on target manifolds with an attractive property, which are referred to as invariants or invariable laws of the target system behavior for the object under study. A necessary preliminary step is the formalization of possible target invariants in the form of prescribed (desired) laws of the controlled object behavior. An example is given of designing a vector regulator with a compensation of random disturbances over the control channel in a system of anaerobic biological waste water treatment.
Determination of the bottom scattering coefficient discontinuity lines in the multibeam ocean sounding
Authors: Kovalenko E O , Prokhorov I V
Published: December 2021

In this paper the problems of constructing sonar images of the seabed according to measurements of the multibeam side scan sonar are considered. The inverse problem for the non-stationary equation of radiation transfer with the diffuse reflection conditions at the boundary which consists in finding the discontinuity lines of the bottom scattering coefficient is investigated. A numerical algorithm for solving the inverse problem is developed, and an analysis of the quality of reconstructing the boundaries of inhomogeneities of the seabed is carried out, depending on the number of views and the width of a radiation pattern and the sounding range.
An inverse problem for a system of nonlinear parabolic equations
Authors: Tabarintseva E
Published: December 2021

The inverse problem for a system of nonlinear parabolic equations is considered in the present paper. Namely, it is required to restore the initial condition by a given time-average value of the solution to the system of the nonlinear parabolic equations. An exact in the order error estimate of the optimal method for solving the inverse problem through the error estimate for the corresponding linear problem is obtained. A stable approximate solution to the unstable nonlinear problem under study is constructed by means of the projection regularization method which consists of using the representation of the approximate solution as a partial sum of the Fourier series. An exact in the order estimate for the error of the projection regularization method is obtained on one of the standard correctness classes. As a consequence, it is proved the optimality of the projection regularization method. As an example of a nonlinear system of parabolic equations, which has important practical applications, a spatially distributed model of blood coagulation is considered.
Earthquake record processing algorithms to form a strong motion database
Authors: Mironov V A , Peretokin S A , Simonov K V
Published: December 2021

This study is devoted to the development of algorithms and software for earthquake record processing. The algorithms are based on the methodology used by the Pacific Earthquake Engineering Research Center for the implementation of the scientific project NGA-West2. The purpose of processing is to determine reliable values of ground acceleration and other parameters of earthquakes from the available records of velocity time series. To analyze the operation of the algorithms, earthquake records (simultaneously recorded time series of acceleration and velocity) taken from the European Rapid Raw Strong-Motion database were used. The developed algorithms and the implemented software will allow in the future to form a database of strong motions for building regional attenuation models on the territory of the Russian Federation.
A divide-and-conquer algorithm for seismic data approximation by the Laguerre series
Authors: Terekhov Andrew V
Published: December 2021

An algorithm of the Laguerre transform for approximating functions on large intervals is proposed. The idea of the considered approach is that the calculation of improper integrals of rapidly oscillating functions is replaced by a solution of an initial boundary value problem for the one-dimensional transport equation. It allows one to successfully avoid the problems associated with the stable implementation of the Laguerre transform. A divide-and-conquer algorithm based on shift operations made it possible to significantly reduce the computational cost of the proposed method. Numerical experiments have shown that the methods are economical in the number of operations, stable, and have satisfactory accuracy for seismic data approximation.
Study on The Characteristics of NaCl Treated Kenaf Fiber Epoxy Composite Board
Authors: Setyayunita T , Widyorini R , Marsoem S N , Irawati D
Published: December 2021

The treatment of kenaf fiber surfaces with chemicals has proven to be an effective method to improve composite properties. Meanwhile, natrium chloride (NaCl) is one of the chemicals that has great potential to be used for modifying natural fibers. Therefore, this study aims to investigate the characteristics of a composite board made from NaCl-treated kenaf fiber and epoxy. The method used was a completely randomized design with two factors, namely the level of NaCl in the treatment solution including 1, 3, and 5%wt, as well as the epoxy content of 10, 20, and 30%wt based on the dry weight fiber. The NaCl treatment was carried out by soaking the fibers in the solution for 1 hour at room temperature, rinsed using water until the pH of the water reached 7, and then dried in an oven at 80ᵒC for 6 hours. Furthermore, the Kenaf fiber and epoxy were mixed manually, while the boards were manufactured using a heat pressing system at 120ᵒC, with a pressure of 3.5 MPa for 10 minutes, and a thickness of 10 mm. The physical and mechanical properties were then evaluated based on JIS A5908. The results showed that the composite board properties were optimum at NaCl 5%, 20% of epoxy, modulus of elasticity and rupture of 2.02 GPa, and 18.63 MPa respectively, internal bonding 1.94 MPa, thickness swelling 2.89 %, and water absorption of 10.49%. The results showed that the physical and mechanical properties of the composite board increased with a high NaCl concentration.
The Efficacy of Pine Wood Pellets reinforced with Active Hexaflumuron Against the Subterranian Termite Coptotermes curvignathus Holmgren
Authors: Arinana  , Silalahi A R E , Hendra D , Nandika D
Published: December 2021

Bait formulation using hexaflumuron is the most used baiting techniques because it is relatively friendly to the environment. One of the potential wood species for bait formulation for termites is pine wood. The resin in pine wood can reduce termites preference. Therefore, the resin contained in pine wood needs to be reduced so that the level of termites preference for pine wood can be increased. This study aims to determine the efficacy of the bait formulation in the form of pellets from pine wood (Pinus merkusiiJungh er de Vries) which was pre-treated with presto (0.4 bar, 100 °C) for one, two, three, four, and five hours with active hexaflumuron (0.25%) against subterranean termitesCoptotermes curvignathus.Pine wood chips were treated with presto for one hour, two hours, three hours, four hours, and five hours. The treated pine wood chips then made into sawdust by 40-60 mesh. Pine sawdust then added with hexaflumuron (0.25%) and formed into pellets without adding any adhesive material and then fed to the subterranean termitesC. curvignathus(JIS K 1571: 2010). Solid pine wood used as a control sample. The result showed that palatability of formulation pellet bait with active hexaflumuron (14.33%) was higher than solid pine wood (6.58%). The formulation of pellet bait with 0.25% active hexaflumuron with presto pre-treatment was able to eliminateC. curvignathustermites.
Specific gravity, Extractive Content, and Natural Durability of Balsa (Ochroma pyramidale) Wood at 3 and 4 years old
Authors: Listyanto T , Poedyastanto E P F , Abqoriah S M , Lukmandaru G
Published: December 2021

The aim was to investigate the specific gravity, extractive content, and natural durability of balsa (Ochroma pyramidale) wood. A total of six trees of balsa at 3 and 4 years old were harvested and cut into the sample of specific gravity, extractive content, and natural durability test. Natural durability was tested according to SNI 01-7207-2006 against dry wood termites (Cryptotermes cynocephalusLight.). Specific gravity, extractive content, mass losses, and termite mortality were measured. Variance analysis was used to find the differences. The results showed that age influenced significantly on specific gravity and mass losses, while axial direction/position influenced significantly on extractive content and mass losses. Variance analysis also showed that radial direction influenced significantly on specific gravity and extractive content. The specific gravity of three years balsa wood is 0.14, which is lower than that of four years old three, which is 0,19. Extractive content in the bottom part (3.95%) is higher than that of in the middle (2.87%) and top (2.74%). Mortality in the bottom part (33.83%) is higher than that of in the middle (10.5%) and top part (5,8%) of the stem. In general, balsa wood is classified into durability class II-III.
Coconut (Cocos nucifera Linn.) Root Extraction and Application as A Fabric Dye with Different Particle Sizes and Extraction Methods
Authors: Pujiarti R , Putri O A
Published: December 2021

Coconut (Cocos nucifera Linn.) root can be used as an alternative to natural dyes because it contains color pigments in the form of flavonoids. Extraction of natural dyes is affected by several factors such as the type of solvent, extraction temperature, ratio of solvent and raw material, particle size, stirring, and extraction time. This study ware aims to determine combination factor of the particles size and extraction methods of coconut root dye on the characteristics and colour fastness of the fabric products. The coconut root powder in 60 and 40 mesh sizes were extracted by boiling distilled water and maceration with 70 and 95% ethanol, respectively. The coconut root dye was tested for the color characteristics and the dye solution was applied to the fabric and tested for the color fastness. The results showed that the particle size and extraction methods used had a significant effect on color intensity while pH value and color index were not significantly different. The highest color intensity was 2.044, the effect of temperature at 30 was 1.949, and the effect of temperature at 100°C was 1.920. The pH value of the coconut root dye solution is acidic with an average pH of 5.85 while the color names from the test results using NADIM 2021 produce three color categories, namely foxtrot, tobacco brown, and pale gold. Although it is not significantly affected by the combination of material size factors and the extraction methods of coconut root dye solution, the results of the color fastness test tend to meet the standards of SNI 8302-2016 regarding the quality requirements for the fastness of written batik. The average grey scale value for each test is 3-4 (Good enough), the staining scale value is 4-5 (Good), and the sunlight resistance test value is 4 (Good).
Total Phenolic Content, Antioxidant, and Sunscreen Activities of Daemonorops draco Resin Extracts from Extraction at Various Ethanol Concentrations and Resin-Solvent Ratio
Authors: Asidah N , Sari R K , Rafi Mohamad , Syafitri UD
Published: December 2021

This research aimed to determine the yield, total phenolic content (TPC), in vitro sunscreen (SPF), and antioxidant activities (AA) ofDamonorops dracoresin (DDR). The DDR was macerated with ethanol at various concentration (EC) namely 100% (E100), 90% (E90), 80% (E80), and 70% (E70) and the DDR:solvent ratio (D:S) were 1:5, 1:10, and 1:15. This research showed that the interaction between the EC and D:S affected AA, SPF, and TPC of DDR extract (DDRE), but it didn’t affect the DDRE yield. The DDR extraction with E70, E100, and D:S of 1:15 produced the highest DDRE yield. The extraction with E70 and three different D:S produced DDRE with the highest TPC. The highest AA of DDRE was obtained from extraction with E80 and D:S 1:10 (E80-10), E70-15, and E90-5 respectively. The highest SPF of DDRE was obtained from the extraction with E90-15, E70-15, E90-5, and E70-10, respectively. The extraction with E70 and D:S of 1:15 is the best extraction condition because it produces DDRE with a yield of 17.4±3.9%-20.71±1.6%; TPC of 263.93±5.25 mg GAE/g DDRS; AA with an IC value of 78.3±0.3 ppm, and sunscreen with an SPF value of 33.1±0.0.
Pine fruit as a media for planting white oyster mushroom (Pleurotus ostreatus)
Authors: Taskirawati I , Askar A , Baharuddin
Published: December 2021

Oyster mushroom is a wood fungus that can grow naturally on dead or weathered trees (saprophytes). The commonly used planting medium for oyster mushroom cultivation is sawn waste from various trees. However, considering the high rate of deforestation, ranging from illegal logging, forest burning, and conversion of forest land functions, it is necessary to make substitutions in terms of the leading media for the growth of oyster mushrooms. In this study, pine fruit is the primary medium for the growth of oyster mushrooms to add alternative materials for growing oyster mushrooms. This study aims to determine the potential of pine fruit as a growth medium for oyster mushroom (Pleurotus ostreatus) by the soaking method using two treatments, namely cold and hot water immersion. In cold water samples, the pine cone powder was soaked for five days, seven days, and nine days for hot water soaked for 1 hour, 2 hours, and 3 hours. The research procedure started preparing oyster mushroom growth media, inoculation, maintenance and growth, and harvesting. The results showed that oyster mushrooms could grow at media soaking in hot water for 2 hours (P2) and 3 hours (P3). Treatments P2 and P3 took 78 days and 105 days, respectively, to grow oyster mushrooms.