bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards responsible science and technology: How nanotechnology research and development is shaping risk governance practices in Australia
Authors: Malakar Yuwan , Lacey Justine , Bertsch Paul M
Published: January 2022

Incorporating perspectives of multiple stakeholders concerning the appropriate balance of risks and benefits of new and potentially disruptive technologies is thought to be a way of enhancing the societal relevance and positive impacts of those technologies. A risk governance approach can be instrumental in achieving balance among diverse stakeholders, as it enables decision-making processes informed by multiple dimensions of risk. This paper applies a risk governance approach to retrospectively examine the development of nanotechnology research and development (R&D) in Australia to identify how risk governance is reflected in the practices of a range of stakeholders. We identify ten risk-related challenges specific to nanotechnology R&D based on a review of the international literature, which provided the foundation for documenting how those working in the Australian nanotechnology sector responded to these global risk-related challenges. This case study research draws on a range of sources including literature review, semi-structured interviews, and a combination of qualitative and quantitative approaches for data analysis to identify key themes and generate visualisations of the interconnections that exist between risk governance practices. The ability to visualise these interconnections from the qualitative data is a key contribution of this research. Our findings show how the qualitative insights and professional experiences of nanotechnologists provide evidence of how risk governance approaches have been operationalised in the Australian nanotechnology R&D sector. The findings generate three important insights. First, the risk research undertaken by Australian nanotechnologists is interdisciplinary and involves multiple stakeholders from various disciplines and sectors. Unlike traditional risk governance approaches, our findings document efforts to assess, not only physical risks, but also social and ethical risks. Second, nanotechnology risk governance is a non-linear process and practices undertaken to address specific challenges occurred concurrently with and contributed to addressing other challenges. Third, our findings indicate that applying a risk governance approach enables greater intersection and collaboration, potentially bridging any disconnect between scientists, policymakers, and the public to realise transdisciplinary outcomes. This research highlights opportunities for developing systematic methodologies to enable more robust risk governance of other new and emerging technologies.
Accurately Modeling Coronavirus Spread in Segments
Authors: Piccone Ashley
Published: January 2022

The Method of Parallel Trajectories allows for close monitoring of pandemic evolution and the impacts of restrictive measures.
An ultrafast and facile nondestructive strategy to convert various inefficient commercial nanocarbons to highly active Fenton-like catalysts
Authors: Wang Junhui , Fu Qi , Yu Jiaxing , Yang Huangsheng , Hao Zhengping , Zhu Fang , Ouyang Gangfeng
Published: January 2022

Significance

The Fenton-like process catalyzed by metal-free materials is one promising strategy for water purification, but to develop catalysts with adequate activity, complicated preparation/modification processes and harsh conditions are always needed, greatly increasing the costs for industrialization. Herein, we developed an ultrafast and facile strategy to convert various inefficient commercial nanocarbons into highly active catalysts by noncovalent functionalization with polyethylenimine (PEI). The n-doping by PEI could create net charge on the carbon plane and greatly enhance the electron mobility, rendering the catalyst much higher persulfate activation efficiency. Such interface engineering represents an innovative, simple, yet effective, strategy for boosting activities of nanocarbons, providing a conceptual advance to design cost-effective and highly efficient catalysts in environmental remediation, chemical synthesis, and fuel-cell applications.
Translanguaging to enhance reading comprehension among first-year medical students
Authors: Mbirimi-Hungwe Vimbai
Published: January 2022

Since the turn of the century there has been an increase in the use of translanguaging in multilingual learning contexts. Many researchers have shown how translanguaging enhances multilingual students’ ability to understand academic content. This experimental study provides empirical evidence that translanguaging can enhance reading comprehension. An experimental group and a control group were used to establish whether there was a significant difference between the performances of the two groups after reading an academic text. Using the t-test analysis, the results show a significant difference in the performance of the control group and the experimental group. These findings prompt us to conclude that translanguaging is an effective strategy that enhances reading comprehension.
Fluxless soldering of 7034 aluminium in air using protective liquid Ga coatings
Authors: Luan Tianmin , Xia Yuanhang , Leng Xuesong , Yan Jiuchun
Published: January 2022

Fine-grained 7034 aluminium alloys were soldered with Zn–5Al filler metals, using liquid Ga as protective coatings to remove oxide films of the base and filler metals and prevent secondary oxidation. Holding times and coating modes were adjusted by experiments. Applying the Ga coating on both the base and filler metals caused the Ga enrichment in the α-Al particles and the formation of Mg2Ga5 intermetallic compound at the bonding interface, deteriorating joint mechanical performance. Ga enrichment was prevented by applying the coating on the filler metal alone, which avoided the early contact of Ga with Al substrate and reduced the mass of Ga in the joint. The tensile strength increased significantly to 159∼185 MPa with a sufficient holding time.
Sarcomere length in the beating heart: Synchronicity is optional
Authors: Helmes Michiel , Palmer Bradley M.
Published: January 2022

Helmes and Palmer review research by Kobirumaki-Shimozawa et al.
The skyrmion annihilations induced by local reversal of background field in a skyrmion lattice
Authors: Li Yang , Pang Hua
Published: January 2022

The understanding of the creation and annihilation dynamics of a magnetic skyrmion is significant due to its potential applications in information storage and spintronics. Although there have been extensive investigations on the annihilation of isolated skyrmions, topological annihilation in a periodic skyrmion lattice is a more complex process. We report a micromagnetic simulation study about the annihilation process of a two-dimensional (2D) skyrmion triangular lattice triggered by a uniform field H
REV of comparable size to the skyrmion, which is opposite to the direction of the background field, revealing two annihilation modes. When the H
REV center is within the range of a skyrmion, the neighboring skyrmions annihilate in-situ, while the center is between adjacent skyrmions, an anti-skyrmion is induced in the interstitial region. Both mechanisms tend to experience the intermediate topological vortex or antivortex structure, and the spin system undergoes a long period of relaxation to reach a stable state after the topological charge is stabilized. Our results present a local annihilation scheme that is easy to achieve in a 2D skyrmion lattice and highlight the role of interaction between skyrmions in the transformation between different kinds of topological defects.
Electron glass signatures up to room temperature in disordered insulators
Authors: Delahaye J , Grenet T
Published: January 2022

This paper describes the observation of non-equilibrium field effects at room temperature in four disordered insulating systems: granular Al, discontinuous Au, amorphous NbSi and amorphous indium oxide thin films. The use of wide enough gate voltage ranges and a cautious analysis of the data allow us to uncover memory dips (MDs), the advocated hallmark of the electron glass, in the four systems. These MDs are found to relax slowly over days of measurements under gate voltage changes, reflecting the impossibility for the systems to reach an equilibrium state within experimentally accessible times. Our findings demonstrate that these electrical glassy effects, so far essentially reported at cryogenic temperatures, actually extend up to room temperature.
Light controlled bending of a holographic transmission phase grating
Authors: Castagna Riccardo , Di Donato Andrea , Strangi Giuseppe , Eugenio Lucchetta Daniele
Published: January 2022

We recorded a permanent phase transmission grating on a thin film made by using a recently developed holographic photomobile mixture. The recorded grating pitch falls in the visible range and can be optically manipulated by using an external coherent or incoherent low power light source. When the external light source illuminates the grating the entire structure bends and, as a consequence, the optical properties of the grating change. This peculiarity makes it possible to use the recorded periodic structure as an all-optically controlled free standing thin colour selector or light switch depending on the source used to illuminate the grating itself. Additionally, it could open up new possibilities for stretchable and reconfigurable holograms controlled by light as well as thin devices for optically reconfigurable dynamic communications and displays.
Testing the Kerr black hole hypothesis with the continuum-fitting and the iron line methods: the case of GRS 1915+105
Authors: Tripathi Ashutosh , Abdikamalov Askar B. , Ayzenberg Dimitry , Bambi Cosimo , Grinberg Victoria , Liu Honghui , Zhou Menglei
Published: January 2022

The continuum-fitting and the iron line methods are currently the two leading techniques for probing the strong gravity region around accreting black holes. In the present work, we test the Kerr black hole hypothesis with the stellar-mass black hole in GRS 1915+105 by analyzing five disk-dominated RXTE spectra and one reflection-dominated Suzaku spectrum. The combination of the constraints from the continuum-fitting and the iron line methods has the potential to provide more stringent tests of the Kerr metric. Our constraint on the Johannsen deformation parameter α13 is -0.15 < α13 < 0.14 at 3σ, where the Kerr metric is recovered when α13 = 0.
Probing ultra-light axion dark matter from 21 cm tomography using Convolutional Neural Networks
Authors: Sabiu Cristiano G. , Kadota Kenji , Asorey Jacobo , Park Inkyu
Published: January 2022

We present forecasts on the detectability of Ultra-light axion-like particles (ULAP) from future 21 cm radio observations around the epoch of reionization (EoR). We show that the axion as the dominant dark matter component has a significant impact on the reionization history due to the suppression of small scale density perturbations in the early universe. This behavior depends strongly on the mass of the axion particle.

Using numerical simulations of the brightness temperature field of neutral hydrogen over a large redshift range, we construct a suite of training data. This data is used to train a convolutional neural network that can build a connection between the spatial structures of the brightness temperature field and the input axion mass directly. We construct mock observations of the future Square Kilometer Array survey, SKA1-Low, and find that even in the presence of realistic noise and resolution constraints, the network is still able to predict the input axion mass. We find that the axion mass can be recovered over a wide mass range with a precision of approximately 20%, and as the whole DM contribution, the axion can be detected using SKA1-Low at 68% if the axion mass is M
X < 1.86 × 10-20 eV although this can decrease to M
X < 5.25 × 10-21 eV if we relax our assumptions on the astrophysical modeling by treating those astrophysical parameters as nuisance parameters.
Gravitational waves generation in turbulent hypermagnetic fields before the electroweak phase transition
Authors: Dvornikov Maxim
Published: January 2022

We study the production of relic gravitational waves (GWs) in
turbulent hypermagnetic fields (HMFs) in the symmetric phase of the
early universe before the electroweak phase transition (EWPT). The
noise of HMFs is modeled by the analog of the magnetic hydrodynamics
turbulence. The evolution of HMFs is driven by the analogs of the chiral
magnetic effect and the Adler anomalies in the presence of the nonzero
asymmetries of leptons and Higgs bosons. We track the evolution of
the energy density of GWs from 10 TeV down to EWPT and
analyze its dependence on the parameters of the system. We also discuss
the possibility to observe the predicted GW background by the current
GW detectors.
Following up the afterglow: strategy for X-ray observation triggered by gravitational wave events
Authors: Liu Mu-Xin , Tong Hui , Hu Yi-Ming , Chan Man-Leong , Liu Zhu , Sun Hui , Hendry Martin
Published: January 2022

The multi-messenger observation of coalescing compact binary systems promises great scientific treasure. However, synthesising observations from both gravitational wave and electromagnetic channels remains challenging. In the context of the day-to-week long emission from a macronova, the binary neutron star merger GW170817 remains the only event with successful electromagnetic followup. In this manuscript, we explore the possibility of using the early stage X-ray afterglow to search for the electromagnetic counterpart of a gravitational wave event. Two algorithms, the simple and straightforward sequential observation (SO) and the step-wise optimizing local optimization are considered and applied to some simulated events. We consider the WXT from the proposed Einstein Probe as a candidate X-ray telescope, which has a very wide field of view of 3600 deg2. Benefiting from the large field of view and high sensitivity, we find that the SO algorithm not only is easy to implement, but also promises a good chance of actual detection.
Long-term evolution of magnetic fields in flaring Active Region NOAA 12673
Authors: Muhamad Johan , Nurzaman Muhamad Zamzam , Dani Tiar , Pamutri Arun Relung
Published: January 2022

During the lifetime of AR 12673, its magnetic field evolved drastically and produced numerous large flares. In this study, using full maps of the Sun observed by the Solar Dynamics Observatory and the Solar Terrestrial Relations Observatory, we identified that AR 12673 emerged in decayed AR 12665, which had survived for two solar rotations. Although both ARs emerged at the same location, they possessed different characteristics and different flare productivities. Therefore, it is important to study the long-term magnetic evolution of both ARs to identify the distinguishing characteristics of an AR that can produce large solar flares. We used the Space-weather Helioseismic and Magnetic Imager Active Region Patch data to investigate the evolution of the photospheric magnetic field and other physical properties of the recurring ARs during five Carrington rotations. All these investigated parameters dynamically evolved through a series of solar rotations. We compared the long-term evolution of AR 12665 and AR 12673 to understand the differences in their flare-producing properties. We also studied the relation of the long-term evolution of these ARs with the presence of active longitude. We found that the magnetic flux and complexity of AR 12673 developed much faster than those of AR 12665. Our results confirmed that a strong emerging flux that emerged in the pre-existing AR near the active longitude created a very strong and complex AR that produced large flares.
Comparative case study of two methods to assess the eruptive potential of selected active regions
Authors: Zuccarello Francesca , Ermolli Ilaria , Korsós Marianna B. , Giorgi Fabrizio , Guglielmino Salvo L. , Erdélyi Robertus , Romano Paolo
Published: January 2022

Solar eruptive events, like flares and coronal mass ejections, are characterized by the rapid release of energy that can give rise to emission of radiation across the entire electromagnetic spectrum and to an abrupt significant increase in the kinetic energy of particles. These energetic phenomena can have important effects on the space weather conditions and therefore it is necessary to understand their origin, in particular, what is the eruptive potential of an active region (AR). In these case studies, we compare two distinct methods that were used in previous works to investigate the variations of some characteristic physical parameters during the pre-flare states of flaring ARs. These methods consider: i) the magnetic flux evolution and magnetic helicity accumulation, and ii) the fractal and multi-fractal properties of flux concentrations in ARs. Our comparative analysisis based on time series of photospheric data obtained bythe Solar Dynamics Observatory between March 2011 and June 2013. We selected two distinct samples of ARs: one is distinguished by the occurrence of more energetic M- and X-class flare events, that may have a rapid effect on not just the near-Earth space, but also on the terrestrial environment; the second is characterized by no-flares or having just a few C- and B-class flares. We foundthat the two tested methods complement each other in their ability to assess the eruptive potentials of ARs and could be employed to identify ARs prone to flaring activity. Based on the presented case study, we suggest that using a combination of different methods may aid to identify more reliably the eruptive potentials of ARs and help to better understand the pre-flare states.
A GPU based single-pulse search pipeline (GSP) with database and its application to the Commensal Radio Astronomy FAST Survey (CRAFTS)
Authors: You Shan-Ping , Wang Pei , Yu Xu-Hong , Xie Xiao-Yao , Li Di , Liu Zhi-Jie , Pan Zhi-Chen , Yue You-Ling , Qian Lei , Zhang Bin , Chen Zong-Hao
Published: January 2022

We developed a GPU based single-pulse search pipeline (GSP) with a candidate-archiving database. Largely based upon the infrastructure of the open source PulsaR Exploration and Search Toolkit (PRESTO), GSP implements GPU acceleration of the de-dispersion and integrates a candidate-archiving database. We applied GSP to the data streams from the Commensal Radio Astronomy FAST Survey (CRAFTS), which resulted in quasi-real-time processing. The integrated candidate database facilitates synergistic usage of multiple machine-learning tools and thus improves efficient identification of radio pulsars such as rotating radio transients (RRATs) and fast radio bursts (FRBs). We first tested GSP on pilot CRAFTS observations with the FAST Ultra-Wide Band (UWB) receiver. GSP detected all pulsars known from the the Parkes multibeam pulsar survey in the corresponding sky area covered by the FAST-UWB. GSP also discovered 13 new pulsars. We measured the computational efficiency of GSP to be ∼120 times faster than the original PRESTO and ∼60 times faster than an MPI-parallelized version of PRESTO.
Stellar loci IV. red giant stars
Authors: Zhang Ruo-Yi , Yuan Hai-Bo , Liu Xiao-Wei , Xiang Mao-Sheng , Huang Yang , Chen Bing-Qiu
Published: January 2022

In the fourth paper of this series, we present the metallicity-dependent Sloan Digital Sky Survey (SDSS) stellar color loci of red giant stars, using a spectroscopic sample of red giants in the SDSS Stripe 82 region. The stars span a range of 0.55 – 1.2 mag in color g – i, –0.3 – –2.5 in metallicity [Fe/H], and have values of surface gravity log g smaller than 3.5 dex. As in the case of main-sequence (MS) stars, the intrinsic widths of loci of red giants are also found to be quite narrow, a few mmag at maximum. There are however systematic differences between the metallicity-dependent stellar loci of red giants and MS stars. The colors of red giants are less sensitive to metallicity than those of MS stars. With good photometry, photometric metallicities of red giants can be reliably determined by fitting the u – g, g – r, r – i, and i – z colors simultaneously to an accuracy of 0.2 – 0.25 dex, comparable to the precision achievable with low-resolution spectroscopy for a signal-to-noise ratio of 10. By comparing fitting results to the stellar loci of red giants and MS stars, we propose a new technique to discriminate between red giants and MS stars based on the SDSS photometry. The technique achieves completeness of ∼70 per cent and efficiency of ∼80 per cent in selecting metal-poor red giant stars of [Fe/H] ≤ –1.2. It thus provides an important tool to probe the structure and assemblage history of the Galactic halo using red giant stars.
Imprints of the Jittering Jets Explosion Mechanism in the Morphology of the Supernova Remnant SNR 0540-69.3
Authors: Soker Noam
Published: January 2022

I identify a point-symmetric structure in recently published VLT/MUSE velocity maps of different elements in a plane along the line of sight at the center of the supernova remnant SNR 0540-69.3, and argue that jittering jets that exploded this core collapse supernova shaped this point-symmetric structure. The four pairs of two opposite clumps that compose this point symmetric structure suggest that two to four pairs of jittering jets shaped the inner ejecta in this plane. In addition, intensity images of several spectral lines reveal a faint strip (the main jet-axis) that is part of this plane of jittering jets and its similarity to morphological features in a few other SNRs and in some planetary nebulae further suggests shaping by jets. My interpretation implies that in addition to instabilities, jets also mix elements in the ejecta of core collapse supernovae. Based on the point-symmetric structure and under the assumption that jittering jets exploded this supernova, I estimate the component of the neutron star natal kick velocity on the plane of the sky to be ≃ 235 km s−1, and at an angle of ≃47° to the direction of the main jet-axis. I analyze this natal kick direction together with 12 other SNRs in the frame of the jittering jets explosion mechanism.
Visual field inhomogeneous in brain–computer interfaces based on rapid serial visual presentation
Authors: Zhang Shangen , Chen Xiaogang , Wang Yijun , Liu Baolin , Gao Xiaorong
Published: January 2022

Objective. Visual attention is not homogeneous across the visual field, while how to mine the effective electroencephalogram (EEG) characteristics that are sensitive to the inhomogeneous of visual attention and further explore applications such as the performance of brain–computer interface (BCI) are still distressing explorative scientists. Approach. Images were encoded into a rapid serial visual presentation (RSVP) paradigm, and were presented in three visuospatial patterns (central, left/right, upper/lower) at the stimulation frequencies of 10, 15 and 20 Hz. The comparisons among different visual fields were conducted in the dimensions of subjective behavioral and EEG characteristics. Furthermore, the effective features (e.g. steady-state visual evoked potential (SSVEP), N2-posterior-contralateral (N2pc) and P300) that sensitive to visual-field asymmetry were also explored. Main results. The visual fields had significant influences on the performance of RSVP target detection, in which the performance of central was better than that of peripheral visual field, the performance of horizontal meridian was better than that of vertical meridian, the performance of left visual field was better than that of right visual field, and the performance of upper visual field was better than that of lower visual field. Furthermore, stimuli of different visual fields had significant effects on the spatial distributions of EEG, in which N2pc and P300 showed left–right asymmetry in occipital and frontal regions, respectively. In addition, the evidences of SSVEP characteristics indicated that there was obvious overlap of visual fields on the horizontal meridian, but not on the vertical meridian. Significance. The conclusions of this study provide insights into the relationship between visual field inhomogeneous and EEG characteristics. In addition, this study has the potential to achieve precise positioning of the target’s spatial orientation in RSVP-BCIs.
Comparative analysis of air and water flows in simplified hydraulic turbine models
Authors: Skripkin S G , Suslov D A , Litvinov I V , Gorelikov E U , Tsoy M A , Shtork S I
Published: January 2022

This article presents a comparative analysis of flow characteristics behind a hydraulic turbine runner in air and water. Swirling flow with a precessing vortex core (PVC) was investigated using a laser Doppler anemometer and pressure pulsation sensors. The experiments were conducted on aerodynamic and hydrodynamic test rigs over a wide range of hydraulic turbine operating conditions. Part-load modes of hydraulic turbine operation were investigated using the Fourier transform of pressure pulsations obtained from acoustic sensors. The features of the swirling flow were shown for the range of operating conditions from deep partl-load to overload.
Practical application of natural convective heat exchange of electrical equipment with air
Authors: Gubanov S M
Published: January 2022

This paper provides the physical and mathematical model of the air flow in a volume, containing electrical equipment with the heat-generating and heat-absorbing surfaces. The model predicts the temperature fields and air flow velocities across the volume. Using the developed model, we calculate the values of heat fluxes in the vicinity of the thermostated electrical equipment for three different cases: natural convective, forced and mixed modes of the airflow. The possibility of beneficial use of natural convective air flows for the transfer of thermal energy is analyzed. The results are applied in an industrial enterprise. Energy consumption for ventilation is significantly reduced.
The percolation model of relative conductivities and phase permeabilities
Authors: Kolesnikov B P , Arushanyan R R
Published: January 2022

The universal mathematical model of relative conductivities of percolation clusters and phase permeabilities of oil-water-saturated rocks is presented. It is obtained on the basis of percolation theory, porous body physics and statistics. The model takes into account the influence of change in pore space surface properties and the nature of fluid flow on the studied characteristics and may be applied for comprehensive analysis and modeling of technological processes of oil production.
On thermal problems of the solar thermal multigeneration: new nanomaterials and working fluids
Authors: Dmitriev A S , Klimenko A V
Published: January 2022

The study considers various thermophysical problems, including the processes of heating new nanomaterials and nanofluids, as applied to solar thermal multigeneration (steam generation and turbine and turbineless conversion into electrical energy), as well as thermoelectric generation (solar thermoelectric generation) using new nanomaterials, including graphene and its composites. The main unsolved problems of thermohydrodynamics and heat transfer in such systems are noted.
Active thermal interface graphene nanocomposites for thermal control of electronic and power devices
Authors: Babenko D D , Dmitriev A S , Mikhailova I A
Published: January 2022

New experimental and calculated data are presented for active thermal interface materials, in which heat is removed not only due to high thermal conductivity, but also due to the evaporation of liquids, for example, water, inside a nanoporous graphene structure. It is shown that such active thermal interfaces may be new systems of active thermal control.
Problem of maintaining a normal condensate dissolved oxygen concentration
Authors: Vodeniktov A D , Chichirova N D
Published: January 2022

Study presents the results of the steam surface KCS-200-2 reconstruction. In order to maintain the dissolved oxygen concentration, according to the Code of Operation for Power Plants, the steam sparger was installed in condenser hotwell. Despite the abnormal air leakage level, reducing of dissolved oxygen concentration was reached. The dissolved oxygen concentration reduced, on average, by 2 times. As it was expected, in the cases of low inlet cooling water temperature, the final oxygen concentration did not reach the normal level. In last 3 tests the dissolved oxygen concentration was reduced to 19 mg /l. The results show a possibility of described reconstruction experience.
Multicomponent mixing on the “diffusion – convection” transition boundary at elevated pressures
Authors: Kossov V N , Fedorenko O V , Zhaneli M , Mukhatova K
Published: January 2022

An experimental and theoretical study of three-component mixing at the “diffusion – convection” boundary at elevated pressures is carried out. It is shown that the pressure dependence of the dimensionless parameter α, defined as the ratio of the experimental values of the component concentrations to those calculated by the Stefan-Maxwell equations, has characteristic regions due to the interaction of structural formations moving towards each other, in which a transition from one critical motion to another occurs. Within the framework of a linear analysis of the stability of a ternary gas mixture for a vertical circular cylinder channel, it is shown that scale perturbations determining the transition from one type of flow to another correspond to a certain value of the perturbation mode n and the critical Rayleigh numbers.
Experimental study of an internal combustion engine fueled by a low-calorific value producer gas
Authors: Nikitina G I , Kozlov A N , Penzik M V
Published: January 2022

This paper describes an experimental study of the operation of an internal combustion engine of fueled by a low-calorific value gas. The main operating parameters of low-power ICE were determined. Efficiency was also evaluated when the ICE was converted to operate on producer gas. In the experiment, it was shown that the engine reached a stable operating mode under load and data on the temperature and exhaust gases composition were obtained. According to our estimates, in the steady-state operation of the internal combustion engine with a load, the efficiency factor was about 22 %. When using the model gas, the from generator output power, was about 30-40 % of the nominal value, under variable load conditions. However, it was found that in steady-state operation, the power of the internal combustion engine was 40-55% of the nominal value.
Control of ship tank heating systems to increase their energy efficiency
Authors: Syraleva M N , Kudinovich I V
Published: January 2022

An important problem in the operation of icebreakers and Arctic ships is to prevent excessive icing of ballast tanks above the waterline. Uncontrolled ice formation can damage ballast systems and lead to malfunctions of ballast systems during cargo operations. This paper presents an analysis of the dynamics of water temperature in a ballast tank when the heating system is turned on and off. Recommendations on the control algorithm for the heating system that provides maximum energy efficiency are proposed.
Problems of acoustic safety in power engineering
Authors: Tupov V B , Taratorin A A , Skvortsov V S , Mukhametov A B
Published: January 2022

Environmental safety issues are becoming increasingly important in the life of society. Among environmental safety issues in power engineering, acoustic safety occupies a special place. The problem of acoustic safety is associated with the fact that the regular operation of power equipment leads to an increased noise level, and power facilities are located in close proximity to residential areas. In this work, acoustic calculations were performed to determine the sanitary protection zone for gas turbines units (GTU) and combined cycle gas turbine units (CCGT) of various capacities. A formula was obtained for calculating the width of the sanitary protection zone depending on the capacity of gas turbine units and combined cycle plants and their number. It is shown that the sanitary protection zone (SPZ) of a power unit of high capacity is smaller than the sanitary protection zone of several power units of the same capacity. It is found that the noise levels from individual groups of equipment can determine the noise level at the entire border of the sanitary protection zone or in its individual sections. At the same time, noise suppression measures should be taken for all sources that generate noise levels in excess of standards. It is necessary to start noise suppression measures from those sources that generate excess noise in a larger section of the sanitary protection zone.
Properties of anhydrous hydrogen fluoride in the temperature range from 140 K to 190 K
Authors: Gubanov S M
Published: January 2022

This paper presents the analysis of the known empirical formulas on the pressure of the saturated vapors of hydrogen fluoride depending on the temperature. The possibility of using the formulas to determine the vapor pressure under the low temperatures is assessed. The calculation error of the pressure value depending on temperature outside the interval are determined.
The investigation of the average diameter of the SiO2 nanoparticles effect on the oil displacing efficiency from the pore in the rock formation using nanosuspension as a displacing agent
Authors: Lobasov A S , Minakov A V
Published: January 2022

The numerical investigation of the nanofluid flow, which displaced the oil, in a microchannel was carried out. The effect of the average diameter of the SiO2 nanoparticles on the oil displacing efficiency by nanofluids for different sizes of microchannel at various Reynolds numbers was studied. A T-shaped microchannel with a vertical channel, called a pore channel, which imitated the pore in the rock formation was considered as a computational domain. The main flow channel width and height were 200 µm. The width and height of the pore channel were varied in the range from 100 µm to 800 µm. The Reynolds number varied from 0.1 to 100. The oil recovery coefficient, which is defined as the ratio of the displacing volume of oil from the pore to the volume of the pore was considered as the main studied characteristic. The nanofluid is considered a single-phase fluid with experimentally obtained properties. The mass concentration of SiO2 nanoparticles was 0.5%. The average diameters of nanoparticles were 5 nm, 18 nm, and 50 nm. It was found, that the oil recovery coefficient increased with a decrease in the average diameter of nanoparticles. It was obtained that the nanofluid can enhance the oil recovery several times compared to pure water.
Mathematical modelling of thermal microexplosion in a catalyst granule with point sources of heat release
Authors: Derevich I V , Fokina A Yu
Published: January 2022

A mathematical model of heat and mass transfer in a spherical catalyst granule is proposed. Exothermic synthesis reactions are carried out on point active centres located inside a porous ceramic granule. From the surface of the granule the heat of catalytic reactions is removed into liquid synthesis products. The rate of a chemical reaction is modelled by a modified Arrhenius law. In contrast to the homogeneous model of a catalytic granule methods for calculating heat transfer processes in a system of point, active centres do not develop. An iterative procedure is suggested to calculate the unknown temperature and concentration of the reagent at the active centre. It is shown that the temperature of the active centres is significantly higher than in the volume of the granule. The results of modelling a thermal explosion with increasing granule size and reactor temperature are presented.
Investigating the characteristics of the development of the boundary layer motion of locally nonequilibrium systems
Authors: Popov V I , Kuznetsov A V
Published: January 2022

The method of integral momentum transfer relations has been extended to polymer systems with a locally nonequilibrium relaxation microstructure. The influence of the locally non-equilibrium transfer of the impulse flux on the characteristics of the development of their boundary-layer motion is analyzed.
Application of machine learning to predict the thermal power plant process condition
Authors: Sultanov M M , Boldyrev I A , Evseev K V
Published: January 2022

This paper deals with the development of an algorithm for predicting thermal power plant process variables. The input data are described, and the data cleaning algorithm is presented along with the Python frameworks used. The employed machine learning model is discussed, and the results are presented.
Experimental studies of the formation of zones resulted from air flow around a system of model buildings
Authors: Meshkova V D , Dekterev A A , Dekterev D A , Lobasov A S
Published: January 2022

This paper presents the results of working out the methodology for conducting experimental studies of the flow around the objects modeling the urban environmental conditions. The experiments were conducted in the wind tunnel of the Siberian Federal University. Two objects of different heights imitating buildings were considered the models. Special attention was paid to the study of the flow pattern at the tandem arrangement of model buildings. Visualizing the flow, the low-velocity and high-velocity zones, as well as recirculation areas were identified. At that, these zones had their peculiarities in terms of the direction of flow twisting behind each object. The study allowed revealing that the vortices separating from the edges of the studied objects play a special role in the flow formation.
Features of the educational program «Nanotechnologies and nanomaterials in energy»: machine learning
Authors: Babenko D. D. , Dmitriev A. S. , Makarov P.G. , Mikhailova I.A.
Published: January 2022

The results of the development of new educational programs in the field of nanotechnology and nanomaterials in the energy sector, which have been developed and are actively used by the National Research University “MPEI”, are presented. Modern nanomaterials and nanotechnological processes in traditional and alternative (“green”) energy require new approaches, including statistical methods for the analysis and synthesis of experimental data and design options. For this reason, without the active use of machine learning methods, it is impossible to train qualified specialists in the field of promising energy problems and their solutions. Through teaching, research, and innovation, «MPEI» exceptional community pursues its mission of service to the nation and the world.
Long-term Variation of Absorption and Total Aerosol Optical Properties over Typical Provinces of China from Satellite Observations
Authors: Li Heng
Published: January 2022

Increase of atmospheric aerosols has a profound impact on the Earth’s climate. It’s also one of the crucial factors that cuasesd more fequent air pollution events in China. Monthly average Aerosol Optical Depth (AOD) from MODIS and UltraViolet Absorbing aerosol Index (UVAI) from OMI during 2011 to 2019 are used to analyse the trend of absorption and total aerosol optical properties over three typical provinces of China, namely Shandong, Gansu and Guangdong provinces. The results show the average annual AOD of the three provinces are all decreasing while UVAI rises during this period. In addition, the monthly variation of AOD and UVAI are also obviously different over these provinces. In particular, the peak value of AOD appeared in July and the trough appeared in December over Shandong Province. And the peak appeared in April over Gansu Province, but AOD decrease slower then over Shandong Province. And there were two peaks in April and August over Guangdong Province. For UVAI, the peaks over Shandong and Gansu provinces both occur in January, while that over Guangdong Province appears in March. Above mentioned differences in the long-term trend and monthly variation of AOD and UVAI might be closely related to the meteorological conditions and aerosol emission of these three provinces.
Preparation and the Catalytic Properties of Attapulgite / TiO2 Nanocomposites
Authors: Shang Jianping , Li Tao , Qin Xiaoping , Zhao Bin , Li Xuefei
Published: January 2022

With the rapid development of industry, the discharge of textile printing and dyeing wastewater will cause serious pollution to other pure water bodies. It is imperative to deal with textile printing and dyeing wastewater. In this paper, with titanium tetrachloride as a precursor, attapulgite (ATP) / TiO2 nanocomposites were prepared by a neutralizing hydrolysis method and their catalytic activities were investigated by the oxidative degradation of methylene blue dye using ozone as oxidant. The test results showed that there were significant interactions between TiO2 and ATP support. The effects were also studied of ozone concentration, catalyst amount, reaction temperature, and initial concentration of methylene blue on the degradation rate of methylene blue catalyzed by the prepared attapulgite / TiO2 nanocomposites, and under the optimal conditions, the methylene blue could be degraded more than 90% in 30 minutes. Compared with that of pure ATP, the catalytic activities of ATP / TiO2 nanocomposites were enhenced remarkably. The degradation mechanism of methylene blue was also discussed.
Wastewater Treatment by Enhanced H2O2 – Based Advanced Oxidation Process (AOP) Methods: A Review
Authors: Wu Qitong
Published: January 2022

The development of industries leads to large amount of organic wastewater that contains phenol and dyes. For the treatment of these pollutants, the applications of H2O2 based – AOP have advantages in less pollution, low costs and high efficiency. In order to promote the degradation effect of H2O2, researchers used several methods to strengthen the effect of H2O2 based – AOP. This article mainly reviews the development of catalysts of the strengthened Catalytic Wet Hydrogen Peroxide Oxidation (CWPO), Fenton-like and other assistant-H2O2 systems in the degradation of phenol and dyes recent years. Challenges and development directions concerning catalysts in the future are discussed.
Verification Analysis of the Relationship Between Soil Pressure and Displacement of Retaining Structure
Authors: Chen Jinyong , Li Zhongchao , Liang Rongzhu , Jiang Guosheng , Wu Wenbing
Published: January 2022

Variation laws of earth pressure accounting for the displacement of are taining wall can be well described by mathmatical fitting in the study of the relationship between earth pressure and retaining wall displacement. The common mathematical function expressions of earth pressure displacement of retaining wall can be divided into sinusoidal function model, exponential like function model, hyperbolic function model, fitting function and semi-numerical and semi-analytical model function, etc. The characteristics and shortcomings of the current expression of earth pressure displacement function are summarized. Then combined with the field test and model test, the applicability and characteristics of various mathematical functions in predicting the displacement of earth pressure with retaining structures are analyzed. The results show that when the displacement is small, the sinusoidal function model and the quasi-exponential function model are close to the measured results. When the displacement of retaining structure is large, the fitting results of hyperbolic model and semi-numerical and semi-analytical model are better. For the prediction of earth pressure displacement relationship in passive area, the buried depth has a great influence. And the error between the theoretical value and the actual value has a great influence on the fitting result of the model.
Preparation and Properties of Nano ZnO Dye Sensitized Solar Cells on (Titanium) Substrates
Authors: Cao Ping
Published: January 2022

Nowadays, the development of science and technology has been increasing demand for energy. Energy problem has become a bottleneck to restrict the development of international social economy. People pay more and more attention to the development and research of renewable resources. Solar energy is a kind of renewable resource with great potential and no pollution. The commercialized solar cells are mainly silicon solar cells, among which the conversion efficiency of single silicon solar cells is the highest, but the cost of silicon solar cells is high. Therefore, people have been exploring new materials, among which titanium based nano ZnO dye sensitized solar cells have been paid more and more attention by scientists at home and abroad. Based on this, the preparation and performance of nano ZnO dye sensitized solar cells based on titanium are studied. In this paper, the optical anode materials of DSSC are used as the research objects. Three-dimensional ZnO nanoband, one-dimensional graded ZnO nanotube array and one-dimensional sub grade ZnO nanowire array are prepared by anodizing and hydrothermal synthesis. The photovoltaic properties of the three materials are studied. One dimensional graded ZnO, nanotube array films were prepared by two-step hydrothermal synthesis. One dimensional hierarchical ZnO nanowire array is obtained by two-step hydrothermal synthesis. The results show that DSSC is assembled by one-dimensional graded ZnO nanotube array film, and the photoelectric conversion efficiency is 5.1%. Compared with one-dimensional ZnO nanowire array, the efficiency is improved by nearly 90%. The ZnO nanowire of the sub grade is used instead of DSSC The efficiency of photoelectric conversion is only 4% in the photoanode, which is higher than that of the smooth ZnO nanowire photocell.
The Determination of Metronidazole and Chlorhexidine Gluconate in Metronidazole and Chlorhexidine Lotion by HPLC
Authors: Yun Yun , Lin Mingshi
Published: January 2022

Objective “To establish an HPLC method for the determination of metronidazole and chlorhexidine gluconate in metronidazole and chlorhexidine lotion. Method Using Agilent Eclipse-XDB-C18 chromatographic column, with 0.05 mol·L-1 potassium dihydrogen phosphate solution 1000 ml plus 13.2 ml 10% tetrabutylammonium hydroxide aqueous solution (pH adjusted to 3.5 by phosphoric acid)-acetonitrile (77:23) as Mobile phase, detection wavelength 230 nm. Results The two components could be separated well. The linear ranges of metronidazole and chlorhexidine acetate were 36.33~59.04 μg·ml-1 (r = 0.9994) and 35.45~220.11 μg·ml-1 (r = 1).); The average recoveries were 100.6% and 100.5 %, and the RSD were 0.42% and 0.58%. Conclusion: The method is simple and specific, and the result is more accurate and reliable. Which is suitable for simultaneous determination of two components in compound preparations.
Analysis of Construction Monitoring and Control of Tunnels Crossing Broken Faults and Water-rich Geology
Authors: Fang Jingang
Published: January 2022

In view of the poor geology such as tunnel engineering crossing faults or passing faults, the construction of surrounding rock and support is complicated. During construction, it is necessary to ensure the stability of the surrounding rock and supporting system, and ensure the timing of the secondary lining construction. For this reason, through the analysis and processing of monitoring data, the law of stratum change is mastered, and the supporting parameters and construction methods are adjusted and revised at the same time, so as to provide the best information for the tunnel surrounding rock and supporting lining construction.