bluuebunny/crossref_metadata_2025 huggingface dataset:
Multidecadal declines in particulate mercury and sediment export from Russian rivers in the pan-Arctic basin
Authors: Zolkos Scott , Zhulidov Alexander V. , Gurtovaya Tatiana Yu. , Gordeev Vyacheslav V. , Berdnikov Sergey , Pavlova Nadezhda , Kalko Evgenia A. , Kuklina Yana A. , Zhulidov Danil A. , Kosmenko Lyudmila S. , Shiklomanov Alexander I. , Suslova Anya , Geyman Benjamin M. , Thackray Colin P. , Sunderland Elsie M. , Tank Suzanne E. , McClelland James W. , Spencer Robert G. M. , Krabbenhoft David P. , Robarts Richard , Holmes Robert M.
Published: March 2022

Significance

Russian rivers are the predominant source of riverine mercury to the Arctic Ocean, where methylmercury biomagnifies to high levels in food webs. Pollution controls are thought to have decreased late–20th-century mercury loading to Arctic watersheds, but there are no published long-term observations on mercury in Russian rivers. Here, we present a unique hydrochemistry dataset to determine trends in Russian river particulate mercury concentrations and fluxes in recent decades. Using hydrologic and mercury deposition modeling together with multivariate time series analysis, we determine that 70 to 90% declines in particulate mercury fluxes were driven by pollution reductions and sedimentation in reservoirs. Results suggest that Russian rivers likely dominated over all other sources of mercury to the Arctic Ocean until recently.
Human cytomegalovirus lytic infection inhibits replication-dependent histone synthesis and requires stem loop binding protein function
Authors: Albright Emily R. , Morrison Kylee , Ranganathan Padhma , Carter Dominique M. , Nishikiori Masaki , Lee Jeong-Hee , Slayton Mark D. , Ahlquist Paul , Terhune Scott S. , Kalejta Robert F.
Published: March 2022

Significance

Until now, it was not known if, how, or why pathogenic human viruses might modulate the
de novo
production of the replication-dependent (RD) histone proteins that decorate their DNA genomes within infected cells. Our finding that human cytomegalovirus (HCMV) inhibits RD histone production affirms that a virus targets this fundamental cellular process. Furthermore, our revelation that HCMV induces, relocalizes, and then commandeers the stem loop–binding protein (SLBP) for a purpose other than RD histone synthesis to support productive replication illuminates the potential for other functions of this highly conserved protein. The critical nature of SLBP for HCMV infection and of RD histone synthesis for cellular DNA replication highlights this process as a target for future antiviral and chemotherapeutic interventions.
Photovoltaic effect by soft phonon excitation
Authors: Okamura Yoshihiro , Morimoto Takahiro , Ogawa Naoki , Kaneko Yoshio , Guo Guang-Yu , Nakamura Masao , Kawasaki Masashi , Nagaosa Naoto , Tokura Yoshinori , Takahashi Youtarou
Published: March 2022

Significance

The quantum-mechanical geometric phase of electrons provides various phenomena such as the dissipationless photocurrent generation through the shift current mechanism. So far, the photocurrent generations are limited to above or near the band-gap photon energy, which contradicts the increasing demand of the low-energy photonic functionality. We demonstrate the photocurrent through the optical phonon excitations in ferroelectric BaTiO
3
by using the terahertz light with photon energy far below the band gap. This photocurrent without electron-hole pair generation is never explained by the semiclassical treatment of electrons and only arises from the quantum-mechanical geometric phase. The observed photon-to-current conversion efficiency is as large as that for electronic excitation, which can be well accounted for by newly developed theoretical formulation of shift current.
Enhanced magnetism and suppressed magnetoelastic coupling induced by electron doping in Ca1−
x
Y
x
MnReO6
Authors: Cavichini A S , Orlando M T D , Fantini M C A , Tartaglia R , Galdino C W , Damay F , Porcher F , Granado E
Published: March 2022

The Ca2MnReO6 double perovskite is a spin–orbit-assisted Mott insulator with exotic magnetic properties, including a largely non-collinear Mn2+ spin arrangement and nearly orthogonal coupling between such spins and the much smaller Re 5d magnetic moments. Here, the electron-doped compound Ca1−x
Y
x
MnReO6 (x = 0.1, 0.2 and 0.3) is reported and a detailed investigation is conducted for x = 0.3. Neutron and x-ray powder diffraction confirm that nearly full chemical order is maintained at the Mn and Re sites under the Y substitution at the Ca site. X-ray absorption measurements and an analysis of the Mn–O/Re–O bond distances show that the Mn oxidation state remains stable at +2 whereas Re is reduced upon doping. The electron doping increases the magnetic ordering temperature from T
c = 121 to 150 K and also enhances significantly the ferromagnetic component of the Mn spins at the expense of the antiferromagnetic component at the base temperature (T = 3 K). The lattice parameter anomalies at T
c observed in the parent compound are suppressed by the electron doping. The possible reasons for the enhanced magnetism and the suppressed magnetoelastic coupling in Ca1.7Y0.3MnReO6 are discussed.
Pressure-enhanced superconductivity in cage-type quasiskutterudite Sc5Rh6Sn18 single crystal
Authors: Lingannan Govindaraj , Joseph Boby , Sundaramoorthy Muthukumaran , Kuo Chia Nung , Lue Chin Shan , Arumugam Sonachalam
Published: March 2022

Sc5Rh6Sn18 with a cage-type quasiskutterudite crystal lattice and type II superconductivity, with superconducting transition temperature T
c = 4.99 K, was investigated under hydrostatic high-pressure (HP) using electrical transport, synchrotron x-ray diffraction (XRD) and Raman spectroscopy. Our data show that HP enhance the metallic nature and T
c of the system. T
c is found to show a continuous increase reaching to 5.24 K at 2.5 GPa. Although the system is metallic in nature, Raman spectroscopy investigations at ambient pressure revealed the presence of three weak modes at 165.97, 219.86 and 230.35 cm−1, mostly related to the rattling atom Sc. The HP-XRD data revealed that the cage structure was stable without any structural phase transition up to ∼7 GPa. The lattice parameters and volume exhibited a smooth decrease without any anomalies as a function of pressure in this pressure range. In particular, a second order Birch–Murnaghan equation of state can describe the pressure dependence of the unit cell volume well, yielding a bulk modulus of ∼97 GPa. HP Raman investigations revealed a linear shift of all the three Raman modes to higher wavenumbers with increasing pressure up to ∼8 GPa. As the pressure enhances the bond overlap, thus inducing more electronic charges into the system, HP-XRD and Raman results may indicate the possibility of obtaining higher T
c with increasing pressures in this pressure range.
Opportunities and challenges for 2D heterostructures in battery applications: a computational perspective
Authors: Browne Stephen , Waghmare Umesh V , Singh Anjali
Published: March 2022

With an increasing demand for large-scale energy storage systems, there is a need for novel electrode materials to store energy in batteries efficiently. 2D materials are promising as electrode materials for battery applications. Despite their excellent properties, none of the available single-phase 2D materials offers a combination of properties required for maximizing energy density, power density, and cycle life. This article discusses how stacking distinct 2D materials into a 2D heterostructure may open up new possibilities for battery electrodes, combining favourable characteristics and overcoming the drawbacks of constituent 2D layers. Computational studies are crucial to advancing this field rapidly with first-principles simulations of various 2D heterostructures forming the basis for such investigations that offer insights into processes that are hard to determine otherwise. We present a perspective on the current methodology, along with a review of the known 2D heterostructures as anodes and their potential for Li and Na-ion battery applications. 2D heterostructures showcase excellent tunability with different compositions. However, each of them has distinct properties, with its own set of challenges and opportunities for application in batteries. We highlight the current status and prospects to stimulate research into designing new 2D heterostructures for battery applications.
Maize starch derived boron doped carbon spheres via facile solvothermal route as the photoluminescence sensor for determination of pH and Cr(VI)
Authors: Zhang Wenzhi , Hao Lijuan , Shang Luwen , Chai Dong-feng , Gao Yueyue , Li Jinlong , Zhao Ming , Liu Rong , Zhang Zhuanfang , Dong Guohua
Published: March 2022

In this work, a kind of boron doped carbon spheres (B-CSs) was successfully synthesized utilizing maize starch as carbon source and boric acid as dopant via facile solvothermal method. The chemical structure of the prepared B-CSs was systemically investigated by TEM, FT-IR, XRD, XPS and EDS. The synthesized B-CSs feature spherical structure with average size of ∼254 nm and exhibit strong photoluminescence (PL) with maximum emission at a wavelength of ∼453 nm under irradiation at 350 nm, leading to a quantum yield of 6.2%. Furthermore, the aqueous pH and Cr(VI) has a significantly various impact on the PL intensity of B-CSs, which can be flexibly utilized as the PL sensor for detection aqueous pH and Cr(VI) in aqueous. Particularly, the B-CSs have a desirable sensitivity and selectivity for detection of Cr(VI) with a low detection limit of ∼0.34 μmol l−1. Conclusively, our work provides a novel and dual-functional fluorescent sensor for detection of the pH and toxic metal ions in water environment.
Application of MoS2-FeS functional carrier loaded Ni single-atom catalysts on HER: first principle
Authors: Dong Shizhi , Li Yanshuai , Hu Xudong , Sun Shiyin , Yan Bing , Hu Hongyu , Zhang Xing , Wang Zeliang , Guo Lin
Published: March 2022

The stability of functional carriers single-atom catalysts can be effectively guaranteed by using stable mineral materials to support low dimensional catalytic materials. In this paper, the theoretical calculation of electrochemical hydrogen evolution reaction (HER) of the composite functional single-atom catalysts supported by single-atom Ni was carried out using first-principles method. And the original structure of MoS2, amorphous structure and S-vacancy structure are studied. Through the analysis and discussion of electronic properties, adsorption energy and active sites, it is found that Ni@Amorphous MoS2-FeS has excellent effect of hydrogen evolution in acidic environment, ΔG
H is 0.312 eV, and the other two structures supporting Ni single-atom also have excellent HER properties in a wide range of pH. This design broadens the research idea of single-atom catalysts carriers and provides a new direction for the research and development of electrocatalytic materials.
Enhanced performance of asymmetric supercapacitor based on NiZn-LDH@NiCoSe2 electrode materials
Authors: Cai Bin , Li Jialun , Wang Liying , Li Xuesong , Yang Xijia , Lü Wei
Published: March 2022

While supercapacitors have been widely studied as the next generation of energy storage devices, to develop active electrode materials for enhancing device performance is still challenging. Herein, we fabricated asymmetric supercapacitors based on NiZn-Layered double hydroxide (LDH) @NiCoSe2 hierarchical nanostructures as electrode materials. The NiZn-LDH@NiCoSe2 composites are deposited on Ni foam by a two-step strategy, in which NiZn-LDH nanosheets were firstly grown on Ni foam by hydrothermal method, and then NiCoSe2 particles were prepared by electrodeposition. Due to the synergistic effect between NiZn-LDH and NiCoSe2, excellent device performance was achieved. In a three-electrode system, the NiZn-LDH@NiCoSe2 exhibits a specific capacitance of 2980 F g−1 at 1 A g−1. Furthermore, the asymmetric supercapacitor of NiZn-LDH@NiCoSe2//activated carbon (AC) device was assembled, which exhibits the energy density of 49.2 Wh kg−1 at the power density of 160 W kg−1, with the capacity retention rate is 91% after 8000 cycles. The results indicates that NiZn-LDH@NiCoSe2 is a promising candidate as electrode materials for efficient energy storage devices.
3D modelling of coupled electromagnetic-mechanical responses in REBCO coils involving tape inhomogeneity
Authors: Niu Mengdie , Yong Huadong , Zhou Youhe
Published: March 2022

Electromagnetic and mechanical properties are crucial components of high-temperature superconducting magnet in high-field applications. In this research, in order to predict the multi-field behaviors of REBCO coils during the ramping process, the coupled electromagnetic-mechanical model is constructed with consideration of the strain and magnetic field dependences of the critical current of coated conductors (CCs). The 3D modelling is used to characterize the longitudinal in-homogenous critical current of a CC, which also allows for handling the coil with local defects. To verify the reliability of the coupled model, a comparison of numerical simulations with experiments for a small REBCO coil is first performed with special attention on the hoop strain evolution during the magnetization process. On this basis, the coupled model is then utilized to study the influences of local critical current non-uniformity defined by a Gaussian statistical distribution. The numerical analysis shows that, the tape inhomogeneity has an obvious impaction on decreasing the critical current of REBCO coil. And in high-field scenario, the calculated critical current of coil is highly reduced when the mutual interaction between electromagnetic and mechanical fields is considered. Afterwards, a detailed comparative study is carried out in studying the screening current effects of REBCO coil with and without taking the tape inhomogeneity into account. Finally, the effects of cooling-down process, co-winding materials and local defects are investigated to understand their role in electromagnetic-mechanical response of high-field REBCO coils.
Generation of pure spin-valley beams at controllable angles by gate voltage in monolayer molybdenum disulfide
Authors: Gowdini S , Kanjouri F
Published: March 2022

Strong spin–orbit coupling and lack of inversion symmetry in monolayer transition metal dechalcogenides has made these materials as a promising candidate for both spintronic and valleytronic applications. We investigate the effect of adjustable parameters on quantum transmission of electrons through a magnetic barrier on MoS2 monolayer and introduce selection rules for generation of perfectly polarized spin-valley beams in various directions. These selection rules provide an efficient tool for versatile electrical manipulation of spin-valley beams in two-dimensional structures.
Analytic extensions of Starobinsky model of inflation
Authors: Ivanov Vsevolod R. , Ketov Sergei V. , Pozdeeva Ekaterina O. , Vernov Sergey Yu.
Published: March 2022

We study several extensions of the Starobinsky model of inflation, which obey all observational constraints on the inflationary parameters, by demanding that both the inflaton scalar potential in the Einstein frame and the F(R) gravity function in the Jordan frame have the explicit dependence upon fields and parameters in terms of elementary functions. Our models are continuously connected to the original Starobinsky model via changing the parameters. We modify the Starobinsky (R + R
2) model by adding an R
3-term, an R
4-term, and an R
3/2-term, respectively, and calculate the scalar potentials, the inflationary observables and the allowed limits on the deformation parameters by using the latest observational bounds. We find that the tensor-to-scalar ratio in the Starobinsky model modified by the R
3/2-term significantly increases with raising the parameter in front of that term. On the other side, we deform the scalar potential of the Starobinsky model in the Einstein frame in powers of y = exp(-√(2/3)ϕ/M
Pl), where ϕ is the canonical inflaton (scalaron) field, calculate the corresponding F(R) gravity functions in the two new cases, and find the restrictions on the deformation parameters in the lowest orders with respect to the variable y that is physically small during slow-roll inflation.
Transition metal anchored on C9N4 as a single-atom catalyst for CO2 hydrogenation: A first-principles study
Authors: Chen Jia-Liang , Hu Hui-Jia , Wei Shi-Hao
Published: March 2022

To alleviate the greenhouse effect and maintain the sustainable development, it is of great significance to find an efficient and low-cost catalyst to reduce carbon dioxide (CO2) and generate formic acid (FA). In this work, based on the first-principles calculation, the catalytic performance of a single transition metal (TM) (TM = Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, Cd, Ir, Pt, Au, or Hg) atom anchored on C9N4 monolayer (TM@C9N4) for the hydrogenation of CO2 to FA is calculated. The results show that single TM atom doping in C9N4 can form a stable TM@C9N4 structure, and Cu@C9N4 and Co@C9N4 show better catalytic performance in the process of CO2 hydrogenation to FA (the corresponding maximum energy barriers are 0.41 eV and 0.43 eV, respectively). The partial density of states (PDOS), projected crystal orbital Hamilton population (pCOHP), difference charge density analysis and Bader charge analysis demonstrate that the TM atom plays an important role in the reaction. The strong interaction between the 3d orbitals of the TM atom and the non-bonding orbitals (1π
g) of CO2 allows the reaction to proceed under mild conditions. In general, our results show that Cu@C9N4 and Co@C9N4 are a promising single-atom catalyst and can be used as the non-precious metals electrocatalyst for CO2 hydrogenation to formic acid.
Growth of high material quality InAs/GaSb type-II superlattice for long-wavelength infrared range by molecular beam epitaxy
Authors: Lin Fang-Qi , Li Nong , Zhou Wen-Guang , Jiang Jun-Kai , Chang Fa-Ran , Li Yong , Cui Su-Ning , Chen Wei-Qiang , Jiang Dong-Wei , Hao Hong-Yue , Wang Guo-Wei , Xu Ying-Qiang , Niu Zhi-Chuan
Published: March 2022

By optimizing the V/III beam-equivalent pressure ratio, a high-quality InAs/GaSb type-II superlattice material for the long-wavelength infrared (LWIR) range is achieved by molecular beam epitaxy (MBE). High-resolution x-ray diffraction (HRXRD), atomic force microscopy (AFM), and Fourier transform infrared (FTIR) spectrometer are used to characterize the material growth quality. The results show that the full width at half maximum (FWHM) of the superlattice zero-order diffraction peak, the mismatching of the superlattice zero-order diffraction peak between the substrate diffraction peaks, and the surface roughness get the best results when the beam-equivalent pressure (BEP) ratio reaches the optimal value, which are 28 arcsec, 13 arcsec, and 1.63 Å, respectively. The intensity of the zero-order diffraction peak is strongest at the optimal value. The relative spectral response of the LWIR detector shows that it exhibits a 100% cut-off wavelength of 12.6 μm at 77 K. High-quality epitaxial materials have laid a good foundation for preparing high-performance LWIR detector.
Effect of spatial heterogeneity on level of rejuvenation in Ni80P20 metallic glass
Authors: Chen Tzu-Chia , Nasution Mahyuddin KM , Jabbar Abdullah Hasan , Shoja Sarah Jawad , Siswanto Waluyo Adi , Pranoto Sigiet Haryo , Bokov Dmitry , Magizov Rustem , Mustafa Yasser Fakri , Surendar A. , Zalilov Rustem , Sviderskiy Alexandr , Vorobeva Alla , Vorobyev Dmitry , Alkhayyat Ahmed
Published: March 2022

Understanding the relation between spatial heterogeneity and structural rejuvenation is one of the hottest topics in the field of metallic glasses (MGs). In this work, molecular dynamics (MD) simulation is implemented to discover the effects of initial spatial heterogeneity on the level of rejuvenation in the Ni80P20MGs. For this purpose, the samples are prepared with cooling rates of 1010 K/s–1012 K/s to make glassy alloys with different atomic configurations. Firstly, it is found that the increase in the cooling rate leads the Gaussian-type shear modulus distribution to widen, indicating the aggregations in both elastically soft and hard regions. After the primary evaluations, the elastostatic loading is also used to transform structural rejuvenation into the atomic configurations. The results indicate that the sample with intermediate structural heterogeneity prepared with 1011 K/s exhibits the maximum structural rejuvenation which is due to the fact that the atomic configuration in an intermediate structure contains more potential sites for generating the maximum atomic rearrangement and loosely packed regions under an external excitation. The features of atomic rearrangement and structural changes under the rejuvenation process are discussed in detail.
Residual field suppression for magnetocardiography measurement inside a thin magnetically shielded room using bi-planar coil
Authors: Yang Kang , Zhang Hong-Wei , Zhang Qian-Nian , Zha Jun-Jun , Huang Deng-Chao
Published: March 2022

For a magnetocardiography (MCG) system inside a magnetically shielded room (MSR), the residual field should be further suppressed to obtain high-quality MCG signals. In this paper, a compensation system has been developed based on the bi-planar coil and the proportional-integral-derivative (PID) controller. The bi-planar coil, derived from the target-field theory and the Tikhonov regularization method, is utilized to generate magnetic field with high uniformity in the pre-defined target region. And the PID controller is introduced to provide dynamic compensation current for the coil, according to the residual field change monitored by a reference SQUID magnetometer. The measurement results show that the noise suppression ratio (NSR) can reach above 20 dB in the low-frequency range from 0.1 Hz to 50 Hz. The DC component and the fluctuation of the residual field in time-domain can be respectively suppressed to 0 pT and 4 pT, indicating that this proposed compensation method is useful for the MCG measurement.
Role of the edge stochastic layer in density pump-out by resonant magnetic perturbations
Authors: Ashourvan Arash , Nazikian R. , Hu Q.M.
Published: March 2022

The role of the edge stochastic layer on particle transport is addressed in DIII-D plasmas with applied resonant magnetic perturbations (RMPs) causing density pump-out (a term used to denote the density reduction at the top of the pedestal due to the applied RMPs). Using an analytical model that adds the stochastic parallel transport of electrons (Harvey et al 1981 Phys. Rev. Lett.
47 102) to the fluid equations, the ambipolar radial electric field and particle flux are calculated simultaneously. In this model the nonambipolar electron particle flux, driven by the stochastic magnetic field, is predominantly balanced by the nonambipolar perpendicular ion flux, driven by toroidal viscosity, across a narrow stochastic layer of order two percent of the plasma radius (0.98 < ψ

n
< 1). The model reproduces the level of density pump-out and its dependence on RMP amplitude near the separatrix for three plasma discharges for which the pedestal foot is at medium to high collisionality

(

2
⩽

ν

sep

*

⩽
30

)

. The experimentally observed and numerically tested inverse density dependence of density pump-out (Hu et al 2020 Nucl. Fusion
60 076001) is accurately captured by the model: an increase in collisionality with density in the pedestal foot results in a decrease in stochastic diffusivity, and hence a decrease in the level of pump-out.
Modification of coal fly ash waste by using core-shell method for Cu2+ adsorbent material
Authors: Saputro S , Mahardiani L , Masykuri M , Yamtinah S , Cinthia
Published: March 2022

This research aimed to study: (1) the utilization of fly ash waste as an adsorbent for the heavy metal ion of Cu2+ (2) the effect of variations in adsorbent contact time on the adsorption capacity of Cu2+, (3) the effect of mass variation and activator on the adsorption capacity of Cu2+ ion. This study was divided into some stages, i.e. fly ash preparation, activation, Fe3O4 preparation, Fe3O4@fly ash nanocomposite synthesis, adsorption process, and characterization analysis. Determination of the functional groups of the adsorbent using a Fourier-Transform Infra-Red (FTIR) spectroscopy. The analysis of the adsorbent’s crystal structure was done using X-ray diffraction. In contrast, the effectiveness of fly ash waste as an adsorbent and the effect of contact time on capacity was done using atomic absorption spectroscopy. Based on the results, it was concluded that: (1) fly ash modified using the core-shell method could be used as an adsorbent for Cu2+ ions. (2) there was no change in the structure of the adsorbent before and after the activation. (3) the optimum contact time of the metal ion Cu2+ adsorption by the adsorbent was 120 minutes using the sample D1 (non-PEG 4000 + 3 g Fly Ash NaOH + 3 g Fe3O4) with 71% adsorption power and adsorption capacity was 0.28368 mg/g.
Impacts of low sintering temperature on microstructure, atomic bonds, and dielectric constant of barium titanate (BaTiO3) prepared by co-precipitation technique
Authors: Suherman B , Nurosyid F , Khairuddin  , Sandi D K , Irian Y
Published: March 2022

Barium Titanate (BaTiO3 or BT) is one of which the most attractive ferroelectric materials that have been widely studied. The fabrication process affects the properties of ferroelectric materials where increasing the sintering temperature is one of the ways to improve their performance. In this study, BT has been synthesized using the co-precipitation technique. The samples were sintered for 4 h with varying sintering temperatures of 700°C and 800°C. The purpose of this study was to investigate the effects of variation of sintering temperatures on the microstructure, dielectric constant, and chemical bonds of BT. The micro structure observed by the X-Ray Diffraction (XRD) showed that the crystal size of the sample at 800°C was larger than the sample at 700°C. Furthermore, the Fourier Transform Infrared (FTIR) analysis revealed that increasing the sintering temperature decreased the intensity of the impurities’ peaks of C-H and C=O atomic bonds in the BT structure. The impurity that appear is the carbonate phase which does not decompose during the formation of BT. Moreover, based on the Resistance Capacitance Inductance (RCL Meter) examination, increasing the sintering temperatures could enhance the dielectric constant of the BT samples from 65 to 162. Thus, it can be inferred, that the increase in the sintering temperature could improve the crystal structure and decrease the impurities phases of the BT materials so that further could enhance the dielectric constant.
Properties of TiO2/PDMS-Ag Composites as Antibacterial Self Cleaning
Authors: Ardhi B P , Alfin M M , Pramono E , Wahyuningsih S
Published: March 2022

TiO2 and TiO2-PDMS/Ag (PDMS = polydimethylsiloxane) composites have been prepared. The synthesis was carried out by preparing TiO2 using ball milling technique for 6, 8 and 10 hours, with the composition of TiO2: ball milling = 1:15; 1:20; and 1:25 (g/g). Furthermore, the TiO2-PDMS/Ag composite was synthesized through the solvent dispersion method with the aid of ultrasonication. The preparation of TiO2-PDMS/Ag composites was carried out with several compositions of TiO2, PDMS and Ag, as well as milling times, aiming to determine the effect of compositions and time of ball milling process on decreasing of TiO2 particle size. The addition of Ag to the TiO2-PDMS composites was carried out to investigate the effect of Ag on the antibacterial activity. TiO2-PDMS/Ag composite coating on glass was done by spray coating method. While the antibacterial activity was measured by determining the zone of inhibition by disc diffusion method against Staphylococcus aurous and Escherichia coli. The results exhibited that the ball milling treatment and milling time affected the change in the crystal size of TiO2. The highest composition of TiO2: ball milling at 1:25 for 10 hours was able to reduce the crystal size of TiO2 from 65.81 nm to 46.17 nm. The other hand, the observation of the physical properties of the contact angle of glass coated TiO2-PDMS/Ag composites before irradiation obtained 107° and after irradiation with visible light the contact angle decreased to 56°, which shows that the TiO2-PDMS/Ag composites exhibit photocatalytic activity in the presence of TiO2/Ag. Furthermore, the observation of antibacterial activity on the TiO2-PDMS/Ag as a self-cleaning photocatalytic materials resulted that the largest inhibition zone reached 11.37 mm, so that the TiO2/PDMS-Ag composites had great potential as an active antibacterial self-cleaning.
Improvement of the characteristics of silica particles extracted from rice husks using chemical-physical method
Authors: Wahyuningsih K , Yuliani S , Wahyudiono  , Hoerudin
Published: March 2022

Silica (SiO2) can be extracted from rice husks and has biodegradable properties. However, the rice husk extraction process using the sol-gel technique generates low-purity silica, making them non-compliant as a filler material on the rubber finished goods industry. This study aimed to improve the characteristics of silica particles extracted from rice husks using the leaching-pyrolysis technique compared to the sol-gel technique. Silica was extracted from rice husks using 1.0 N sodium hydroxide and hydrochloric acid solvent (with concentrations of 0.4 N, 1.0 N, and 2.0 N). The pyrolysis was then conducted at 600 °C for 6 hours. The results showed that the leaching-pyrolysis technique was more effective than the sol-gel technique in improving silica particle characteristics. X-ray fluorescence analysis showed that the SiO2 content increased from 91.00 % to 96.82 %. Likewise, the percentage of amorphous by X-ray diffraction analysis and specific surface area by the Brunauer Emmett-Teller method also increased, namely from 48.20 % to 53.97 % and from 96.486 m2/g to 240.427 m2/g, respectively. Therefore, silica from rice husks with these characteristics is applicable as a filler material that is environmentally friendly and renewable.
Synthesis, characterization and antibacterial test of Tetrakis(3-Aminophenol) Copper(II)Nitrate Hexahydrate
Authors: Sarifudin M , Hayati N N , Rahardjo S B
Published: March 2022

The purposes of this research were to synthesize and characterize of copper(II) with 3-aminophenol and determine its antibacterial activity. The complex was synthesized by refluxing a mixture of metal solution and ligand sulition in 1:4 mole ratio for one hour in methanol. The percentage of copper was 8.88% determined by Atomic Absorption Spectroscopy (AAS) therefore the predicted formula was Cu(3-aminophenol)4(NO3)2(H2O)6. Molar conductivity of the complex was measured by conductivity meter corresponding to 1:2 electrolyte. The thermal analysis of the formed complex indicated that the complex containing six water molecules as hydrates. The magnetic susceptibility measurement showed that the complexes was paramagnetic with μeff= 1.88 BM. Electronic spectra of the formed complex appeared at one transition peak on λ= 446 nm. The infrared spectra of the complex showed a shift of (N-H)
band
and (N-H)
stretch
group absorption in
3230 and 1497 cm−1 compared to 3-aminophenol at 3362 and 1594 cm−1. This fact indicated that the (N-H) functional groups were coordinated to the central metal ion. The plausible formula of the complex was [Cu(3-aminophenol)4](NO3)2.6H2O with a square planar structure. The complex showed no antibacterial activity againts Gram-positive bacteria (S. aureus, S. epidermidis) and Gramnegative bacteria (E. coli, P. aeruginosa).
Safety analysis of paraffin wax based biological shielding for cancer therapy with BNCT method on piercing beamport of Kartini nuclear reactor Yogyakarta
Authors: Sardjono Y , Walhikmah R , Widiatmono R , Mahmudah R S N , Wijaya G S , Triatmoko I M , Widarto
Published: March 2022

Cancer is one of the deadly diseases for humans. According to the World Health Organization (WHO) in 2018, there were 9.6 million deaths caused by cancer. Boron Neutron Capture Therapy (BNCT) is a cancer therapy method that is cell targeting by utilizing the reaction of the Boron-10 core with thermal neutrons. The use of BNCT facilities needs attention regarding the safety of radiation workers. An attempt that could be made is to mount a material on a radiation shield that efficiently blocks neutron and gamma radiation. To optimize the calculation used PHITS computer code. The result can be concluded that the characteristics of paraffin wax were effective in blocking neutron radiation but not effective in absorbing gamma radiation. C36H74
is a paraffin wax with the highest density, but produces the lowest dose rate value. The optimum geometry and radiation shielding materials to with stand neutron and gamma radiation are paraffin wax, aluminum and lead with a thickness of 6 cm on top, bottom and front 5 cm, and left and right 3 and a dose rate value at the top of 2.00 µSv/hour, bottom 6.41 µSv/hour, front 5.55 µSv/hour, left and right 3 µSv/hour respectively.
Thermal properties of hybrid membrane-based PVDF modified with cellulose and silylated cellulose
Authors: Zakaria M A , Fridiasari K F , Ni’mah A F , Macorowalie A , Santoso Y , Saputra O A , Bagaskara M , Mustofa R E , Pramono E , Purnawan C
Published: March 2022

Cellulose extracted from Oil Palm Empty Fruit Bunches has been successfully modified by amino-based and oxirane-based silylating compounds. The modified and unmodified cellulose was incorporated into polyvinylidene fluoride (PVDF) membranes through the phase-inversion. The resulted membranes were further analyzed using Differential Scanning Calorimetry (DSC) to distinguish the thermal properties, including melting temperature and crystallinity of the membranes. Moreover, the water uptake properties of the membranes were discussed in this study. The melting temperature of each membrane is not significantly different. However, PVDF/CellGPTMS has better thermal properties compared to others. The presence of cellulose and its modified product within PVDF membranes improved the crystallinity of the membranes.
A comparative study of kinetics of methylene blue dye using adsorbent andisol and humic acid from lighnite by KOH-hydrothermal method
Authors: Prandini M N , Pranoto  , Marliyana S D
Published: March 2022

A comparative study of adsorption kinetics model of methylene blue (MB) dye using andisol and humic acid (HA) adsorbents from the isolation of lignite with KOH-Hydrothermal has been carried out. The adsorption process was measured by using a UV-Vis Spectrophotometer to determine concentration of the adsorbed MB. The adsorption kinetics was determined using the first-order Langmuir-Hinshelwood kinetic model, the first-order kinetic model of Lagergren (1898), and the pseudo-second-order kinetic model of McKay and Ho. The adsorption kinetic model of MB on andisol and HA followed second-order kinetic model of McKay and Ho, with the reaction rate constant for MB adsorption on andisol higher than the rate constant for MB adsorption on HA. The reaction rate constant for MB adsorption on andisol was 0.0532 g mg−1 minute−1 and the adsorption capacity was 18.9753 mg/gr, while the reaction rate constant for MB adsorption on andisol was 0.0241 g mg−1 minute−1 and the adsorption capacity was 19.7628 mg/gr.
New route for synthesis and characterization sulfonated chitosan using acetyl sulfate as a sulfonating agent
Authors: Bagaskara M , Azizah A , Ni’mah A F , Hapsari P Z , Saputra O A , Dewi C , Pramono E
Published: March 2022

The purpose of this study was to synthesis and characterized sulfonated chitosan using acetyl sulfate. Sulfonated chitosan has been successfully synthesized using an alternative sulfonating agent using acetyl sulfate. Sulfonated chitosan was prepared by varying the volume of acetyl sulfate against chitosan for 1 hour at 40 oC and then terminated and filtered to obtain sulfonated chitosan. The sulfonated chitosan was characterized using Fourier Transform Infrared (FTIR), thermal analysis, and cation exchange capacity (CEC). FTIR data showed that all variation of sulfonated chitosan have sulfonate groups attached to both amine and hydroxyl group from chitosan. Thermal analysis showed lower thermal stability of sulfonated chitosan than chitosan. CEC data shows that the highest value obtained 14,5 mmol/g for addition 25 mmol acetyl sulfate. Sulfonated chitosan shows a high value of CEC and it has a promising material for polymer electrolyte membrane in Fuel Cells technology.
Molecular dynamics study of a nano-scale β-type Stirling engine
Authors: Kitaya K , Isobe M
Published: March 2022

A Stirling engine is based on a thermodynamic cycle; a temperature difference causes flywheel rotation. Because the arbitrary (stochastic) heat resources contact some of the systems that generate the work (i.e., the energy), Stirling engines remain important in the present era of Sustainable Development Goals because of their broad applicability. This study focuses on a nano-scale “β-type” Stirling engine, specifically concerning a model for numerical simulation. We perform molecular dynamics simulation of the two-dimensional model (using hundreds of particles) and calculate the thermal efficiency. We figured out the minimal necessary conditions for stable rotation, as well as the lower limits of particle numbers and temperature differences for autonomous thermodynamic cycles.
Nonequilibrium dynamics of a fluid vesicle: Turing patterns and traveling waves
Authors: Noguchi Hiroshi , Tamemoto Naoki
Published: March 2022

In living cells, the shapes of biomembranes are dynamically regulated by proteins. We briefly review our recent studies on the membrane dynamics coupled with reaction-diffusion dynamics of curvature-inducing proteins. We simulated a vesicle in a fluid phase using a dynamically triangulated membrane model combined with a modified Brusselator model. The mechanochemical feedback of curvature-inducing proteins changes the condition of Turing patterns relative to those that occur on a non-deformable curved surface. Budding and multi-spindle shapes are also stabilized by Turing patterns. The speed of traveling waves increases or decreases with increasing local membrane curvature depending on the condition. Moreover, the reaction-diffusion waves can induce the self-oscillation of vesicle shapes.
Theoretical Study of Dissociation Process of Plastocyanins by PaCS-MD Simulation
Authors: Fitrasari D , Arwansyah M S , Kawaguchi K , Purqon A , Suprijadi  , Nagao H
Published: March 2022

We present a procedure of calculation of free energy landscape of two proteins by using parallel cascade molecular dynamics (PaCS-MD) and multiple independent umbrella sampling (MIUS). The free energy landscape of two plastocyanins for association/dissociation process is investigate by using the present method. We find that binding free energy is around 1 kcal/mol and that the barrier energy at around the middle range between the equilibrium point and the dissociation state becomes about 1 kcal/mol from the association process. The present results suggest that the energy barrier may arise from hydrogen bonds between two plastocyanins. We also find that the effective interaction between two plastocyanins already vanishes at the distance of 2 Å from equilibrium state. The equilibrium point of the complex around 27.9 Å is a good agreement with the experimental result 27.8 Å
Enhancing efficient computation of long-wavelength relaxation dynamics in a 2D liquid involving millions of particles
Authors: Shiba Hayato
Published: March 2022

Recently, a two-dimensional liquid cooled toward the glass transition was found to exhibit a t
−1 long-time tail in the velocity autocorrelation function (VACF) owing to the presence of long-wavelength fluctuations. To directly observe this power-law behaviour, it is necessary to simulate a large system with millions of particles, which is a challenging task from the computational viewpoint. In this study, to address this difficulty, I first show that this power-law tail can be reproduced by differentiating the finite-time diffusivity with respect to time. In addition, the feasibility of another direction, a direct on-the-fly computation of the VACFs utilizing GPGPUs, wherein VACFs are evaluated as the simulation runs, is also demonstrated. A performance benchmark was executed on Wisteria/BDEC-01 (Aquarius subsystem) supercomputer using a simulation code developed by the author, which enabled the direct computation of the VACF of 4 million particlesx for as long as the 108 simulation steps within 10 days.
Higher Order Auxiliary Field Quantum Monte Carlo Methods
Authors: Goth Florian
Published: March 2022

The auxiliary field quantum Monte Carlo (AFQMC) method has been a workhorse in the field of strongly correlated electrons for a long time and has found its most recent implementation in the ALF package (alf.physik.uni-wuerzburg.de). The utilization of the Trotter decomposition to decouple the interaction from the non-interacting Hamiltonian makes this method inherently second order in terms of the imaginary time slice. We show that due to the use of the Hubbard-Stratonovich transformation (HST) a semigroup structure on the time evolution is imposed that necessitates the introduction of a new family of complex-hermitian splitting methods for the purpose of reaching higher order. We will give examples of these new methods and study their efficiency, as well as perform comparisons with other established second and higher order methods in the realm of the AFQMC method.
QMC study of the chiral Heisenberg Gross-Neveu universality class
Authors: Otsuka Yuichi , Seki Kazuhiro , Sorella Sandro , Yunoki Seiji
Published: March 2022

We investigate a quantum criticality of an antiferromagnetic phase transition in the Hubbard model on a square lattice with a d-wave pairing field by large-scale auxiliary-field quantum Monte Carlo simulations. Since the d-wave pairing filed induces Dirac cones in the non-interacting single-particle spectrum, the quantum criticality should correspond to the chiral Heisenberg universality class in terms of the Gross-Neveu theory, which is the same as those expected in the Hubbard model on the honeycomb lattice, despite the unit cells being different (e.g., they contain one and two sites, respectively). We show that both the two phase transitions, expected to occur on the square and on the honeycomb lattices, indeed have the same quantum criticality. We also argue that details of the models, i.e., the way of counting the total number N of fermion components and the anisotropy of the Dirac cones, do not change the critical exponents.
Density-matrix renormalization-group study for a two-dimensional lattice-gas on the Ih-ice prism surface
Authors: Akutsu Noriko
Published: March 2022

The phase transition temperature of a two-dimensional (2D) lattice-gas model for the Ih-ice prism surface ((1010) surface on a wurtzite crystal structure) is calculated using the density-matrix renormalization-group (DMRG) method. Since the unit cell on the prism surface contains four atoms without inversion symmetry, the asymmetric version of the DMRG is required to obtain a precise value of the phase transition temperature. The effective bond energy on the surface is obtained by comparing the phase transition temperature with the faceting transition temperature observed for a real ice crystal. Using the effective bond energy, the temperature dependence of the coverage on sub-lattice sites is calculated. The surface tensions on the (0001) surface (the basal plane) and the prism plane are also calculated. The surface tension of the basal plane for the ice/water interface agrees well with the recent calculated values obtained by large scale molecular dynamics.
Unified Time Evolution Approach for the Electronic Structure Calculation
Authors: Wang Q , Zempo Y
Published: March 2022

In imaginary-time evolution, the same technique, Crank–Nicolson’s method, as for the analysis of real-time evolution is employed. For the verification using the model oscillators such as quantum well, Morse, and harmonic potentials, practical density functional theory (DFT) calculations are performed for hydrogen atoms and molecules. The convergence is confirmed to be faster under appropriate initial and boundary conditions. The results are consistent with the analytical solutions and those of other DFT calculations. Imaginary-time evolution is quite convenient to subsequent real-time real-space time-dependent DFT calculation. Although the operators are different, similar evolution is adopted. This technique is expected to unify into practical electronic state calculations for the self-consistent electronic structure and system’s response due to perturbation because calculations are in the same framework as the time-dependent equation.
Optical Properties of OLED Materials by TDDFT
Authors: Akino N , Zempo Y
Published: March 2022

For the material design of organic light emitting diodes, it is highly desired to simulate the spectral profile, that is, not only the peak wavelength but also its spectrum shape. Time dependent density functional theory in real-space and real-time formalism is applied to simulate the spectrum profile of typical organic materials, poly(9,9’-dioctyl-fluorene) and Ir(ppy)3. Although the some red-shift in the peak wavelength has been observed due to the use of the local density approximation, the overall simulated profiles agree well with the experiments. Although the study is in preliminary stage, the results show that this approach may be able to simulate the spectrum profile reasonably well within a reasonable computation time.
Phenomenological Simulations of Intermediate States in a Type I Superconducting Wire
Authors: Mizuhara Yohitaka , Kato Masaru
Published: March 2022

We have investigated superconducting state of a type I superconducting wire solving the Ginzburg Landau equation with finite element method. When a critical current is applied to a type I superconducting wire, superconductivity becomes inhomogeneous. We find superconductivity shows oscillatory structures which are similar to London proposed intermediate state. In the simulations, we impose two types of boundary conditions, phase-fixed and vector potential-fixed. Under both boundary conditions, we have obtained similar periodic structures.
The Unstable Analysis of Soliton Compression in Silicon Photonic Crystal
Authors: Phibanchon Sarun
Published: March 2022

Soliton solutions to the perturbed nonlinear Schrodinger equation, for describing the wave in the photonic crystal, can be found by the sine-Gordon expansion method. This method provides both bright and dark soliton solutions. The instability of the perturbed bright soliton in the perpendicular direction to the wave motion cab be expressed in terms of the growth rate. The time evolution of the unstable soliton can be visualized from the transformation to the higher dimensional solitons by the spectral method.
Plasma propagation via radiation transfer in millimeter-wave discharge under subcritical condition
Authors: Suzuki S , Kato C , Takahashi M , Ohnishi N
Published: March 2022

An improved model was proposed to reduce a computational cost for subcritical millimeter-wave discharge. The proposed model was able to reproduce the plasma-front propagation via radiation transport as similar to the conventional model, and the plasma-front propagation speed was in agreement with the previous simulation. An electron transport effect by neutral fluid advection, which has been introduced into the conventional model, does not affect the propagation speed. By using the presented model, a computational time was reduced by 35%, which was suitable for a multi-dimensional simulation in the future.