bluuebunny/crossref_metadata_2025 huggingface dataset:
Variability of polar flows
Authors: Derzho Oleg
Published: December 2020

It is anticipated that the physical mechanism of the variability of polar currents may be attributed to temporal and spatial variations of the cyclonic mean flow due to circularly propagating nonlinear Rossby waves. A low order analytical model for the effect of large scale and low frequency variability of a polar current is presented. Rossby wave packet is shown to be an intrinsic mode of motion trapped between the major flows, which constitute the mean current. The Rossby wave pattern is predicted to rotate with a specific angular velocity, which depends on both the magnitude and width of the time averaged flow. Spatial structure of the rotating pattern, including its zonal wave number, is defined by the specific form of the stream function-vorticity relation. Theoretically predicted patterns capture the main features of the Antarctic Circumpolar Wave (ACW). The model is capable to predict the observed sequence of warm and cold patches in the ACW along with its zonal number.
Liquid Velocity Distribution in a Flat Channel with Sudden Expansion
Authors: Evdokimenko I A , Kulikov D V , Lobanov P D , Pribaturin N A
Published: December 2020

The experimental study of the flow structure behind the sudden expansion of the flat channel is performed. The cross section of the channel is 20×200 mm and the step height is 12 mm. Visualization of the flow structure and measurements by means of particle image velocimetry (PIV) is performed using high power green laser sheet and CCD camera. Liquid velocity profiles are measured by means of laser Doppler anemometry (LDA). Automatic position system is used. The structure of liquid flow distribution evolution behind the sudden channel expansion is shown. The data about pressure drop is presented for different liquid flow rates.
High-order numerical method for scattering data of the Korteweg—De Vries equation
Authors: Gudko A , Gelash A , Mullyadzhanov R
Published: December 2020

Nonlinear wavefields governed by integrable models such as the Korteweg–De Vries (KdV) equation can be decomposed into the so-called scattering data playing the role of independent elementary harmonics evolving trivially in time. A typical scattering data portrait of a spatially localised wavefield represents nonlinear coherent wave structures (solitons) and incoherent radiation. In this work we present a fourth-order accurate algorithm to compute the scattering data within the KdV model. The method based on the Magnus expansion technique provides accurate information about soliton amplitudes, velocities and intensity of the radiation. Our tests performed using a box-shaped wavefield confirm that all components of the scattering data are computed correctly, while the test based on a single-soliton solution verifies the declared order of a numerical scheme.
Patterns of vortex generation behind a cylinder in a wall-bounded cross-flow during transition to turbulence
Authors: Molochnikov V M , Mazo A B , Kalinin E I , Paereliy A A , Kluev M A
Published: December 2020

The paper elaborates on experimental investigation and direct numerical simulation of the wake flow behind a circular cylinder located near the wall of a rectangular channel. The study considers the Reynolds number range that covers transition to turbulence in the wake. Spiral fluid motion directed from the sidewalls to the channel center is revealed behind the cylinder for both positions of the cylinder considered in the study. The paper describes the effect of this motion on the critical Reynolds number corresponding to the onset of Karman vortex street and on the vortex topology. The spiral motion is shown to correlate with the onset of low-pressure regions behind the cylinder near the sidewalls. These regions result from the interaction between the boundary layer on the sidewalls and the separation region behind the cylinder.
Numerical simulation of unsteady combustion at elevated pressure and initial temperature of the mixture for the model combustion chamber
Authors: Dekterev Ar A , Lobasov A S , Dekterev A A
Published: December 2020

The paper presents the results of investigation of combustion features of a fuel-lean methane-air swirling flame in a model combustion chamber using numerical simulation at an elevated pressure and initial temperature of the mixture. The equivalence ratio is 0.7, the initial temperatures of the mixture are 300 and 500 K, and the overpressure corresponds to 2 and 4 bars. Setting the increased pressure as the output boundary conditions in the numerical simulation of combustion in a model combustion chamber is shown to be efficient. It is found that a change in the initial temperature of the mixture from 300 to 500 K (at a fixed Reynolds number equal to 30000) leads to a significant change in the combustion regime. So, in the case of the initial temperature of the mixture equal to 300 K, the recirculation zone is formed only near the walls of the combustion chamber, and the flame has a compact shape, and is stabilized inside the premixer. With elevated initial temperatures of the mixture, a stagnation region is formed on the jet axis, and the flame displacement downstream relative to the premixer exists.
Effect of the mixture initial temperature on the velocity field in the swirling flame
Authors: Sharaborin D K
Published: December 2020

The paper presents the results of an experimental study of the flow structure of a turbulent swirling flame of a methane-air and syngas-air mixture at elevated temperature using modern optical methods PIV (Particle Image Velocimetry) and PLIF (Planar Laser-Induced Fluorescence). A comparison of the averaged flow characteristics of a high-swirl flame with an equivalence ratio Φ = 0.45 for syngas-air and Φ = 0.7 for methane-air mixture are performed with preheating the mixture to a temperature of 300, 400 and 500 K. The distribution of the fluorescence signal showed that the longitudinal size of the region of hot combustion products decreases significantly with increasing temperature of the mixture for both syngas-air and methane-air flames. For the flame of a mixture of methane-air and syngas-air heated to a temperature of 500 K, the size of the recirculation zone and velocity pulsation distribution are very similar, in contrast to a methane flame at lower preheating temperatures of the mixture.
Heat transfer on microstructured surfaces with pool boiling of various liquids
Authors: Aksianov R A , Kokhanova Yu S , Kuimov E S , Ley R A , Popov I A , Skrypnik A N
Published: December 2020

Recommendations for predicting heat transfer coefficients and critical heat fluxes are developed on the basis of available experimental data on heat transfer and critical heat fluxes for boiling of different liquids on microstructured surfaces realized by deformed cutting method. Microstructured surfaces allow intensifying heat transfer 1.1 to 6 times. Due to the variable wettability of microstructured surface elements, critical heat fluxes increase over 4 times. The proposed criteria equations allow predicting heat transfer coefficients with an error of 30%, and critical heat fluxes with an error of 30-35%. The equations are of interest for designing cooling systems for microelectronic devices, heat and mass transfer devices, boiling zones of heat pipes and thermosyphons, etc.
Numerical simulation of heat transfer during the liquid cooling of complex surfaces at unsteady heat release
Authors: Chernyavskiy A N , Pavlenko A N
Published: December 2020

The presented mathematical model allows simulating the heat transfer process during the liquid cooling of complex surfaces under conditions of unsteady heat release. The numerical simulation can be provided for the case of film cooling as well as for channel heat exchangers. The presented simulation approach is based on the Finite Volume Method (FVM) which makes it possible to perform the calculations for heat exchangers with complex geometry. Usage of the Volume of Fluid (VOF) method allows simulating the heater cooling by the liquid film with a free surface. The presented mathematical model was tested on a set of specific problems. The simulation results are in satisfactory agreement with the known solutions.
Peculiarities of the initialization and dynamics of the quench front on an extremely overheated plate cooled by a falling film of a cryogenic fluid
Authors: Starodubtseva I P , Pavlenko A N
Published: December 2020

Quenching is a generally accepted term for the process of rapid cooling of a solid body that is superheated above the temperature of the thermodynamic limit of a liquid superheat. The paper presents the results of computational experiments simulating the quenching of a high-temperature vertical copper plate by a gravitationally flowing film of liquid nitrogen. The peculiarities of the initialization and dynamics of the quench front in the transition process are investigated. The initial temperature of the test sample was higher than the Leidenfrost temperature and even higher than the critical temperature, which excluded the possibility of long-term stable liquid-solid contact. An improved numerical model of quenching is implemented, which assumes at the time of the quench front initialization an unsteady local contact of the liquid with the extremely overheated surface in the vicinity of the upper boundary of the heater. A dynamic pattern of the running quench front was obtained numerically, which satisfactorily correlates with that observed in cryogenic experiments by the high-speed digital video camera. The reliability of the results obtained numerically is confirmed by direct comparison with experimental data on the velocity and the shape of the quench front.
Numerical simulation of the energy-saving device for ventilation with periodic veering of an air flow
Authors: Aktershev S P , Mezentsev I V , Mezentseva N N
Published: December 2020

Two-dimensional mathematical model of energy-saving device for ventilation with cyclic veering of an air flow is developed. Results of calculations by two-dimensional model are compared with those obtained by one-dimensional model and with experimental data. It is shown that one-dimensional model [4] basically correctly describes the heat exchange in terms of temperature, averaged over cross-section. Parametrical researches are fulfilled by a method of numerical modelling to optimise the operating of the regenerative heat exchanger. Influence of parameters of the device on its energy efficiency is revealed.
Improving the energy efficiency of flaring in pulverized coal-fired boilers at TPPs of the Siberian Federal District by mechanochemical activation of coal
Authors: Chernova G V , Butakov E B , Burdukov A P
Published: December 2020

The heat power system of the Siberian Federal District is almost coal-based: energy generation at coal-fired TPPs makes up 87.2%. But due to low reactivity of coals fed to the pulverized coal boilers, expensive high-reactive fuel oil is used to ignite and light the pulverized coal flame, which is a technological and economic problem. To increase the energy efficiency of flame burning of coal, an increase in their reactivity due to mechanochemical activation is considered using the technology developed at IT SB RAS. For several different coals, experimental studies on burning were carried out at a 5 MW pilot setup using mechanochemical activation of coal. These studies showed reliable ignition and stable access to the autothermal coal combustion, which indicates an increase in coal reactivity and the ability to replace fuel oil with coal.
Mathematical modeling of plasma-thermal gasification of technogenic wastes
Authors: Domarov P V
Published: December 2020

The electrical and thermal characteristics of a plasma-resistive furnace in the drying zone during the utilization of industrial waste have been investigated. The dependences of the power released in the drying zone for various electrical resistivity of the mixture were obtained. It is shown that the introduction of additional resistive heating in the drying zone reduces the load on the plasmatron, increasing the lifetime of the electrodes.
Numerical investigation of coal-water fuel combustion in two-chamber furnace of a low-power boiler
Authors: Kuznetsov Viktor , Maltsev Leonid , Dekterev Alexander
Published: December 2020

In this work, a 1 MW hot water boiler equipped with a two-chamber combustion chamber for droplet-flame combustion of a coal-water fuel (CWF) is studied numerically. The effect of the second chamber with screen tubes on aerodynamics of the exhaust gas flow and temperature redistribution in the furnace volume is shown.
Analysis of the influence of heat and mass transfer processes in the WWER equipment on the duration of effective operation of passive safety systems
Authors: Shlepkin A S , Sakhipgareev A R , Morozov A V
Published: December 2020

The paper presents the results of an experimental study of the possibility of increasing the autonomous operation of passive safety systems of the WWER-1200 reactor facility. In the course of experiments conducted at IPPE JSC, processes that have a significant impact on the performance of these systems were studied. Non-condensing gases coming from the reactor negatively affect the operation of the steam generator in emergency condensation mode. They can significantly reduce the intensity of the condensation process and the duration of cooling the core. At a large-scale test facility HA-2M, the experiment was conducted to determine the maximum duration of a steam generator in the absence of removal of non-condensable gases from its tube bundle.
Employing one-dimensional approach to calculate mixture composition evolution caused by gas-phase reactions for the gas flowing through a cylindrical channel
Authors: Gorbachev Yu E , Leschev D V , Plotnikov M Yu , Shkarupa E V
Published: December 2020

Two approaches to evaluate the mixture composition with a small reactive admixture for the gas flowing through a cylindrical channel are compared. Both are based on solving the Navier-Stokes equations. In the first one, the Navier-Stokes equations are solved for the reacting gas mixture. In the second one, they are solved for non-reacting mixtures and gas-phase reactions are taken into account by solving the one-dimensional (along the flow axis) chemical kinetics equations. Comparison of the obtained results for CH4+H2 mixture have shown the possibility of using of one-dimensional approach for correct description of the mixture composition evolution caused by gas-phase reactions.
Effect of pressure on the hydrogen dissociation degree in a hot tube
Authors: Morozov A A , Plotnikov M Y , Rebrov A K , Yudin I B
Published: December 2020

The effect of pressure decrease on the degree of dissociation of hydrogen flowing inside a hot tube was studied. The experimental data were analysed using the previously developed thermal model of the reactor. The heat exchange of gas with the tube wall was estimated based on the direct Monte Carlo simulation. It was shown that decreasing the pressure from 20 mm Hg down to 1 mm Hg leads to a slight increase in the degree of hydrogen dissociation, from 11% up to 13%.
Effect of temporal evolution of the evaporation surface temperature on the plume expansion under pulsed laser ablation
Authors: Morozov A A
Published: December 2020

The effect of the temporal evolution of the evaporation surface temperature on the neutral plume expansion under pulsed evaporation into vacuum has been studied. Two-dimensional calculations have been performed based on the direct simulation Monte Carlo (DSMC) method. The Gaussian distribution of the temporal evolution of the surface temperature is assumed. The regimes with the constant and varying temperature of the evaporation surface have been compared. It is shown that for evaporation of more than ten monolayers the varying temperature leads to a considerable change in the plume dynamics with up to 9% decrease in the average energy of particles passing through a time-of-flight detector on the normal to the surface.
The formation of nonlinear sound fields in the boundary region of the bubble medium
Authors: Ogorodnikov A I
Published: December 2020

The formation of sound fields in the boundary region of a bubble medium under the influence of a powerful sound pulse for different volume concentrations of bubbles is studied. Two characteristic ranges of the volume concentration of bubbles, to the limits of which different types of wave fields are formed, are determined. At low values of volume concentrations in the boundary region, a long-lived space-limited standing sound wave is formed. A standing sound wave contains an order of magnitude more energy than other areas of the bubble medium. At large values of the volume concentration of bubbles in the boundary region of the bubble medium, an excitation zone forms. The structure of the zone is a periodic wave propagating deep into the bubble medium. The wavelength in the excitation zone increases with increasing distance from the boundary.
Comparison of different approaches to simulation of heterogeneous reactions by dsmc method
Authors: Plotnikov M Yu , Shkarupa E V
Published: December 2020

The present work is devoted to simulation of hydrogen dissociation on the surface of a heated wire in a resting gas by the direct simulation Monte Carlo (DSMC) method. Two approaches to simulating heterogeneous reactions are investigated: with and without regard to the velocities of particles impinging on the surface. A numerical study was performed based on a two-step hydrogen dissociation-recombination model.
Control of droplet phase angular distribution under near-wall liquid film ejection with co-current gas flow from the supersonic nozzle into a vacuum
Authors: Prikhodko V G , Yarygin V N , Yarygin I V
Published: December 2020

Flow structure behind a supersonic nozzle under near-wall liquid film ejection with the co-current gas flow into a vacuum is studied experimentally. Quantitative measurement results on the angular distribution of the droplet phase behind supersonic nozzle are obtained using the developed spectrophotometry technique. The authors have revealed the effect of near-wall liquid film parameters (Reynolds number of the film) and co-current gas flow parameters (Reynolds number of gas flow) on the formation of droplet phase backflows. The capability of controlling the droplet phase backflows, using the screens installed on the nozzle exit has been shown as well.
Research of plasma radiation of low pressure dc arc gas discharge
Authors: Sakhapov S Z
Published: December 2020

A spectroscopic analysis of a plasma arc discharge in helium was carried out. In the obtained emission spectra in the wavelength range from 380 to 1100 nm, lines of molecular band systems, such as Swan C2 systems and C I.
Experimental study of the contact line friction coefficient
Authors: Sibiryakov N , Zheng W , Kabov O , Bai B
Published: December 2020

Industrial applications use surfactants to control surface tension and wettability of surfaces. Instead of studying prepared solutions, we focus on the movement of the contact line after adding the surfactant. We placed the pedant drop with surfactant to a sessile drop of pure water and filmed the spreading process to obtain friction coefficient of the contact line. Our results confirmed that adding surfactants to sessile droplets drives the contact line movement. Small concentrations of LHS and SDBS as well as high concentrations of SDBS pin droplet and increase the hysteresis. Friction coefficient for cationic CTAB and zwitterionic LHS drops with the concentration increase. Anionic SDBS decreases contact angle, making the surface more hydrophilic and intensifying hysteresis.
Critical indexes of the nickel thermal diffusivity
Authors: Agazhanov A Sh , Samoshkin D A , Kozlovskii Yu M
Published: December 2020

Using the laser flash method, the thermal diffusivity (a) of nickel was measured in the temperature range of 300–1680 K with a detailed study of the region near the Curie temperature Tc
= 628 K. The initial experimental data in the field of magnetic phase transformation were processed by the scaling dependence, and the critical thermal diffusivity indexes (α, α’) were obtained below and above Tc
: α = 0.86 and α’ = 0.26, which in absolute value significantly exceed the critical heat capacity index. The possible reasons for this difference have been briefly discussed.
Features of thermodynamic properties of single crystals on the basis of lithium tungstate: «thermodynamics – structure – functional characteristics» correlations
Authors: Matskevich N I , Stankus S V , Samoshkin D A , Shlegel V N , Grigorieva V D , Kuznetsov V A
Published: December 2020

On the basis of obtained experimental data, the features of thermodynamic properties for lithium tungstate single crystals doped by molybdenum have been revealed. Correlations between enthalpies and structural parameters have been found. The relation between lattice energies and scintillation characteristics has been revealed.
The use of pulsed infrared drying in the processing of leafy plant raw materials
Authors: Sapozhnikov A N , Sleptsov S D , Grishin M A , Kopylova A V , Levin T A
Published: December 2020

The paper presents the results of research of leafy plant raw materials drying with pulsed infrared (IR) radiation by the example of spinach (Spinacia oleracea L.). The efficiency of the selected method for weight and humidity changes in the processed material has been analyzed. The specific energy consumption for removal of 1 g of moisture as well as ascorbic acid concentration in dried product have been calculated. The results of the analysis show that IR-drying of leafy plant raw materials is efficient and can be carried out in production environment.
Influence of thermal conductivity of the partition wall on non-stationary conjugate natural convective heat exchange and temperature fields in the walls of a rectangular fuel tank
Authors: Berdnikov V S , Mitin K A
Published: December 2020

The non-stationary conjugate heat transfer in a rectangular model of a fully filled thin-walled tank, divided by an internal vertical partition wall into two compartments of 1/3 and 2/3 of the tank volume is studied numerically in the conjugate formulation. The outer surfaces of the end walls and the upper wall of the tank are heat-insulated. The lower wall suddenly warms up under the influence of a uniform heat flux. The calculations are performed at the ratio of the thermal conductivity of solid walls to the thermal conductivity of fuel λs/λf = 1041.3 and λs/λf = 1 (low-heat partition wall) and thermal parameters of fuel T1 (Prandtl number Pr = 25.66). The influence of internal vertical partitions wall on the spatial shape of convective flows and the regularities of non-stationary conjugate heat exchange is studied. The temperature fields in the liquid and in the tank walls are calculated.
Investigation of fluorescence spectra of various types of plastics for the purpose of sorting and further processing
Authors: Maslov N A , Dulin V M
Published: December 2020

Excitation-emission matrices of various plastic package samples were studied. A tuneable 210-310 nm laser was used as an excitation source. The samples of polyethylene terephthalate, polypropylene, and high-density polyethylene of various colour and transparency showed multipeak wideband fluorescence spectra dependent on the excitation wavelength. Principal component analysis demonstrated that the excitation-emission matrices of most samples are well described by two principal components, individual for their types and colorant additives. Despite complex structure of the excitation-emission matrices of different types of the plastic, appropriate linear combinations of the principal components allowed finding a characteristic component for each of them.
Experimental research and development of drilling fluid formulations to reduce the rate of the permafrost thawing
Authors: Mikhienkova E I , Pryazhnikov M I , Neverov A L , Zhigarev V A , Guzei D V
Published: December 2020

The paper is devoted to complex experimental studies of methods to reduce the rate of permafrost thaw during the construction of oil and gas wells in the fields of the Krasnoyarsk territory. Laboratory physical and chemical studies on the development of drilling fluid formulations for drilling in permafrost conditions were carried out. The most significant results were obtained for clay-polymer solutions with the addition of ethylene glycol and propylene glycol. It was shown that it is possible to control the thermal, hydration and filtration characteristics of drilling fluids by introducing ethylene glycol and propylene glycol without deterioration of their rheological properties.
Effect of a uniformly rotating crystal length on radiation-convective heat transfer in the Chokhralsky method
Authors: Mitin K A , Berdnikov V S
Published: December 2020

Radiation-convective heat transfer from silicon crystals to the environment was investigated with the Chokhralsky method. The systems of equations of thermogravitation and mixed convection in the term vortex, stream function and temperature were solved numerically by the finite element method. The influence of crystal rotation on the spatial forms of convective flows of the surrounding gas and on non-stationary temperature fields in the gas and in the crystals was studied. Calculations were made for crystals of different lengths. The calculations were performed with the Prandtl number equal to 0.68 (argon) and the Grashof number 16000, typical for a real technological process.
The effect of coolant temperature at the inlet on heat transfer enhancement for LED module cooling by a micro-jet system
Authors: Trofimova V V , Gatapova E Ya
Published: December 2020

Jet cooling is one of the effective and active methods for thermal control of electronic devices. The paper presents experimental data of the study of heat transfer during multi-jet cooling of a LED module at a power of 100 – 300 W. The influence of the coolant temperature at the inlet on the heat transfer enhancement is investigated. It is shown that with increasing power, the temperature inhomogeneity along the LED surface increases. A significant effect of the coolant inlet temperature on the heat transfer enhancement is shown. Water is used as a coolant. The surface temperature of the LED module is shown to be by 10 °C lower for the coolant inlet temperature of 10 °C in comparison with the coolant inlet temperature of 25 °C at a LED power of 300 W.
Application of GaN in 5G Technology
Authors: Wang Kun , Sheng Chenxu
Published: December 2020

With the progress of informatization, the development of communication technology and the wide application of wide bandgap semiconductors represented by GaN, the application of GaN in 5G technology has received increasing attention. In this paper, various characteristics of GaN application in 5G technology were emphatically introduced and a detailed analysis of these characteristics was conducted on the basis of the GaN application in 5G technology via literature searching and combining what we have learned. In addition, the development and innovation of GaN power devices in recent decades and some problems encountered at the present stage were explained and a certain prediction of the GaN application in 5G technology were proposed that this area will be a great part of industry in 21th century.
Life Cycle Assessment of a New Steel-making Process for Sustainable Steel Industrial Development in China
Authors: Du Shuxuan
Published: December 2020

With the increasing emphasis on sustainable development, the development of green industry has become particularly important. The steel industry, as a key industry with high pollution and high emission, is bearing a huge environmental pressure. In China, the traditional steelmaking industry of blast furnace-converter has the problems of huge energy consumption and carbon emission, which is contrary to the requirements of sustainable industrial development. Therefore, based on the resource characteristics and technical basis of China, the theory of replacing the traditional steel-making process with coal-to-gas-gas-based shaft furnace-electric furnace steel making process is proposed in this paper. At the same time, this paper will establish an LCA model for the new process, objectively evaluate its relationship with the environment, and deeply analyse the relationships between each unit process in coal-to-gas-based shaft furnace-electric furnace process and environmental protection, energy consumption, pollution emission. Through the simulation of steelmaking process and life cycle assessment, the impact of new process on environment and energy is analysed quantitatively. It provides a new research direction and a reliable theoretical support for optimizing steel refining process and developing sustainable steel refining industry.
Graphene quantum dots and polypyrrole incorporated polyacrylic acid hydrogels with enhanced conductivity
Authors: Yongqiang Yang , Qun Wang , Xiaochen Wu
Published: December 2020

Highly conductive hydrogels of functional graphene quantum dots (FGQDs) and polypyrrole (PPy) incorporated polyacrylic acid (FGQDs/PAA20/PPy) were fabricated through chemical cross-linking and in-situ polymerization. The amount of FGQDs, PPy and cross-linker affecting on the morphology, swelling ratio and electrical properties of FGQDs/PAA20/PPy composite hydrogels was investigated. FGQDs produced smaller-sized pores on the structure of PAA hydrogels, but hardly affected their porosity and swelling ratio. A high conductivity of 0.29 S/m was achieved for FGQDs/PAA20/PPy hydrogels, which promised high possibility in various fields.
Research on the Key Technology Application of Industrial Robot in Grinding and Polishing of Pen and Electronic Industry
Authors: Qi Yunxia
Published: December 2020

Taking grinding and polishing industrial robot as the research object, three key technologies in the process of machining are analyzed. Firstly, the selection method of grinding mode is introduced. Secondly, the tool calibration and workpiece calibration method in the process of robot running program editing are introduced. Finally, the singularity phenomenon and improvement method in the process of industrial robot operation are introduced. Through the analysis, the optimization of robot in control, programming, process and other technologies can be improved to meet the actual production needs of grinding and polishing robot seek.
Construction of a cloud-based mold manufacturing system based on JAFMAS
Authors: Zhang Peipei , Wang Dongsheng , Zhang Junhui
Published: December 2020

Molds are the basis of manufacturing of other products, and thus have higher requirements and more complex design processes than other products. Therefore, studying the technologies used in mold production is necessary. This paper aims to build a cloud manufacturing system of mold manufacturing enterprises based on the Java-based agent framework for multi-agent systems (JAFMAS). Specifically, according to the operation characteristics of different cloud-based manufacturing enterprises, this paper first made in-depth analysis of the cloud manufacturing and multi-agent technology, and put forward a hierarchical model of cloud manufacturing system based on multiple agents. Then, as per the structure of the agents and JAFMAS, the interaction and collaboration mechanism between agents in the system were analyzed to establish the functions of the cloud-based mold manufacturing system, thereby building a cloud-based manufacturing system for mold manufacturers based on JAFMAS.
A Super-Resolution Model for Improving the Precision of Wafer Mark Alignment
Authors: Lei Sheng , Lu Sen , Yang Kaiming
Published: December 2020

Wafer bonding machine uses industrial camera to recognize marks on top wafer and bottom wafer, compute deviation, and move top wafer to align the bottom wafer. The alignment precision mainly depends on the camera resolution, high resolution industrial camera is expensive, while classical image up-sampling methods such as bicubic interpolation don’t have good effect. To improve the alignment precision, a super-resolution model is proposed. Main component of this model is convolutional neural network. The first two convolutional layers are to extract feature on wafer image, the next convolutional layer is used for nonlinear mapping, and the final one outputs super-resolution image. Peak Signal to Noise Ratio (PSNR) is used to evaluate the similarity of super resolution image and the target high resolution image. It’s proved by experiments that the super-resolution model has better effect than classical image interpolation methods. This research result can also be applied to other equipment using industrial cameras.
Water conservancy projects enhanced local resilience to floods and droughts over the past 300 years at the Erhai Lake basin, Southwest China
Authors: Xu Anning , Yang Liang Emlyn , Yang Weibing , Chen Hao
Published: December 2020

As a typical mountain area at the Yunnan-Guizhou Plateau in Southwest China, the Erhai Lake Basin has uneven precipitation (frequent droughts and floods), affected by the Southwest Monsoon in Asia and significant vertical zonal differences determined by local topography. Though with such harsh physical environment, this area sustained development in ancient times and has been considered a typical resilience case in many studies. With extensive investigation of various historical archives, this paper explores the situation and changes of water management in the Erhai Basin during the past 300 years, and aims to identify local factors in maintaining resilience to water stresses. Findings indicate that various strong and smart social regulations (governance, institutions, plans, management, motivations, orders, donations, dedication, etc.) enabled a wise development of many water conservancy projects that set up an effective irrigation system at the flat basin center. Lots of stream dams, sluice gates and terraced croplands jointly further enabled water storage, drainage and irrigation at the surrounding hillside areas. Additionally, by adopting drought-resistant and cold-resistant crops, agriculture production kept increasing and successfully fed the growing population. The complex but systematically developed river canal system, with its dams, reservoirs, and sluice gates, as well as adaptive cropping strategies, together maintained and enhanced the resilience of local communities to hydrological hazards. Over the 300 years of the study period, the changing water environment and the developing water conservancy projects showed a resilience loop, which offers a simple but valuable perspective on building human-water resilience in face of current and future water crises in this region and beyond.
Comparison of intermittent audit vs daily documentation of pharmacist interventions
Authors: Turton Hannah , Jones Ceridwen , Levy Russell , Patanwala Asad E
Published: December 2020

Purpose

To compare an intermittent audit method vs a daily documentation method with regard to the number of interventions documented by clinical pharmacists in the hospital setting.

Methods

A 2-phase pre-post cohort study was conducted at an academic hospital to compare numbers and types of pharmacist interventions documented over an 18-month period before implementation of a daily documentation method (the “pre-phase” period) and during the 6 months after implementation (the “post-phase” period). During the pre-phase period (January 2018 to July 2019), pharmacists prospectively documented interventions on specific audit days. The audit days occurred at approximately monthly intervals. During the post-phase period (July 2019 to March 2020) pharmacists used electronic medical record tools to document interventions daily. The primary outcome was the total number of interventions per day. Values for the pre- and post-phase periods were compared using an unpaired Student t test and through interrupted time series analysis.

Results

There were a total of 3,628 interventions (on 14 intermittent audit days) during the pre-phase period and 9,300 interventions (on 163 continuous days) in the post-phase period. The mean (SD) number of reported interventions per day decreased from 259 (82) in the pre-phase period to 57 (33) in the post-phase period (P < 0.001). The mean (SD) number of daily reported interventions per pharmacist decreased from 24 (5) in the pre-phase period to 6 (2) in the post-phase period (P < 0.001). This decrease was consistent with results of the interrupted time series analysis. There was a decrease in reported interventions at the time of implementation (change from most recent audit day, –125 interventions; 95% confidence interval [CI], –187 to –62 interventions; P < 0.001). Similarly, there was a decrease in reported interventions per pharmacist at the time of implementation (change from most recent audit day, –22 [95% CI, –26 to –18] interventions; P < 0.001).

Conclusion

A change from intermittent audits to daily documentation of interventions resulted in an approximately 5-fold decrease in the number of interventions recorded by pharmacists.
Acute heart and brain failure: a case report
Authors: Stuetz Magdalena , Templin Christian , Templin-Ghadri Jelena-Rima , Ruschitzka Frank , Pohl Heiko , Hofer Daniel
Published: December 2020

Background

Takotsubo syndrome (TTS) is characterized by often reversible but acute heart failure occurring after an emotional or physical trigger event. The ‘brain failure’ counterpart is posterior reversible encephalopathy syndrome (PRES) characterized by often reversible but acute neurological symptoms. This case report elaborates on a complex clinical scenario with co-existence of coronary artery disease, TTS and PRES and discusses the pathophysiology, differential diagnosis, and management.

Case summary

An 82-year-old woman presented with acute heart failure and generalized tonic-clonic seizures following an acute exacerbation of her chronic back pain. Brain magnetic resonance imaging demonstrated vasogenic oedema consistent with the diagnosis of PRES. Focal wall motion abnormalities on echocardiography without causal coronary stenoses on angiography were consistent with the diagnosis of TTS. After an interdisciplinary approach to differential diagnosis and treatment, the patient was discharged to geriatric rehabilitation without heart failure or neurological defects 4 weeks later.

Discussion

TTS and PRES share significant similarities in proposed pathogenesis, epidemiology, management, and clinical outcome. This case report highlights the need for early recognition of this rare association and multidisciplinary approach to diagnosis and treatment as both heart and brain disease may require early intervention up to rapid intensive care support.
The Balance Hypothesis for the Avian Lumbosacral Organ and an Exploration of Its Morphological Variation
Authors: Stanchak K E , French C , Perkel D J , Brunton B W
Published: December 2020

Synopsis

Birds (Aves) exhibit exceptional and diverse locomotor behaviors, including the exquisite ability to balance on two feet. How birds so precisely control their movements may be partly explained by a set of intriguing modifications in their lower spine. These modifications are collectively known as the lumbosacral organ (LSO) and are found in the fused lumbosacral vertebrae called the synsacrum. They include a set of transverse canal-like recesses in the synsacrum that align with lateral lobes of the spinal cord, as well as a dorsal groove in the spinal cord that houses an egg-shaped glycogen body. Based on compelling but primarily observational data, the most recent functional hypotheses for the LSO consider it to be a secondary balance organ, in which the transverse canals are analogous to the semicircular canals of the inner ear. If correct, this hypothesis would reshape our understanding of avian locomotion, yet the LSO has been largely overlooked in the recent literature. Here, we review the current evidence for this hypothesis and then explore a possible relationship between the LSO and balance-intensive locomotor ecologies. Our comparative morphological dataset consists of micro-computed tomography (μ-CT) scans of synsacra from ecologically diverse species. We find that birds that perch tend to have more prominent transverse canals, suggesting that the LSO is useful for balance-intensive behaviors. We then identify the crucial outstanding questions about LSO structure and function. The LSO may be a key innovation that allows independent but coordinated motion of the head and the body, and a full understanding of its function and evolution will require multiple interdisciplinary research efforts.
Characterization of Cannabidiol in Alternative Biological Specimens and Urine, after Consumption of an Oral Capsule
Authors: Ameline Alice , Raul Jean-Sébastien , Kintz Pascal
Published: December 2020

Among the hundred cannabinoids present in Cannabis sativa indica, cannabidiol (CBD) is a phytocannabinoid discovered in 1940, which can account for up to 40% of the plant’s extract. Medically, it has been proposed to treat convulsions, inflammation, anxiety and nausea. Contrary to the hallucinogenic ingredient of the plant, delta-9-tetrahydrocannabinol, CBD does not seem to have a sedative effect, which can increase its popularity among users. The identification of CBD in blood and urine has been widely described in the scientific literature for several years. Only few data have been reported regarding CBD identification in alternative specimens, such as oral fluid, sweat, exhaled breath and hair. CBD capsules were purchased in the USA from a grocery store and a green capsule containing 22 mg of CBD was orally administered to a 59-year-old healthy man. Oral fluid was collected over 8 h using the NeoSal™ device. Sweat was collected using PharmCheck™ sweat patch technology over 7 days. Exhaled breath was collected with the ExaBreath® DrugTrap device over 8 h. Beard hair was collected 7 and 14 days after administration. Finally, urine specimens were collected over 48 h in plastic tubes without preservative. CBD was only detected in oral fluid at 15 min, at 20 pg/mL. Increasing concentrations, up to 96 pg/patch of CBD, were detected in the sweat patches. CBD was detected for 45 minutes in exhaled breath (Cmax of 302 pg/filter at 30 min). CBD produced a very low but significant chromatographic signal in beard hair, with concentrations <1 pg/mg. Finally, CBD tested positive in urine after enzymatic hydrolysis with a Cmax at 70 ng/mL, after 6 h.
Reconstruction of Major Burns With Stevens–Johnson Syndrome: A Case Report and Literature Review
Authors: Ge Xiaojing , Sun Yute , Su Xin , Zhou Fang , Yao Gang
Published: December 2020

Stevens–Johnson syndrome (SJS) is a severe type of pleomorphic erythema and a rare disorder of the skin and mucous membranes, which can lead to serious infections, pulmonary embolism, acute respiratory distress syndrome, multiple organ dysfunction syndrome, and other serious consequences. Patients with SJS are usually treated in burn centers. SJS complicated by severe burns is very rare, and this is associated with a high risk of infection and other more serious complications. With SJS, the availability of donor sites is compromised given the lack of healthy epidermis, and this makes it more difficult to treat. The patient was a 52-year-old man with 45% TBSA burns with 40% TBSA full-thickness burns on both lower limbs. During treatment, his condition was complicated by SJS, renal failure, and respiratory failure. After 31 days, he was transferred to our department. On the 22nd day, the patient recovered from SJS, and after undergoing four skin grafting procedures, the burn wounds healed, and the donor site had healed spontaneously. He was discharged after 86 days of treatment in our department. In conclusion, major burns complicated with SJS are rare clinical presentations. The skin affected by the drug eruptions can be used as a donor site for transplantation to the burn wounds, and this donor area can also heal.
Image-guided Procedure Versus 2-year Follow-up for a BI-RADS 3 Probably Benign Lesion: A Cost Comparison Analysis
Authors: Ong Andrew , Azizi Armina , Ambinder Emily B , Oluyemi Eniola T , Harvey Susan C , Hung Jessica
Published: December 2020

Objective

Perform a comparison between the costs of image-guided breast procedures versus 2-year imaging follow-up for findings classified as BI-RADS assessment category 3-probably benign.

Methods

The national payment amount costs at non-facility locations were obtained from the Centers for Medicare and Medicaid Services physician fee schedule for breast imaging-related Current Procedural Terminology codes. Total costs were calculated and compared for management algorithms of 2-year imaging follow-up of a BI-RADS 3 lesion from 2018 through 2019 versus performing an image-guided procedure of the lesion in 2018 after the initial diagnostic imaging.

Results

Two-year mammographic follow-up of a BI-RADS 3 finding costs $484. This was less than a stereotactic-guided breast biopsy, which cost at least $1055. Two-year follow-up for a probably benign US finding cost $615 compared to $1173 for the least expensive US-guided breast biopsy scenario. For breast MRI, 2-year imaging follow-up cost $1510, which was also less than most MRI-guided breast biopsy scenarios. The one exception in which biopsy costs less than 2-year imaging follow-up was in the setting of an MRI-guided biopsy in the average-risk population without a post-benign biopsy follow-up breast MRI; in this setting, MRI biopsy cost $1235.

Conclusion

In 2018–2019, 2-year imaging follow-up of a BI-RADS 3 finding continues to be less costly than an immediate procedure, except for MRI-guided breast biopsy in the average-risk population without a post-benign biopsy follow-up MRI.
Avian community composition, but not richness, differs between urban and exurban parks
Authors: Haas Angela R , Kross Sara M , Kneitel Jamie M
Published: December 2020

Urban development alters landscape structure and available resources, potentially threatening avian diversity worldwide. However, it is unclear how bird communities respond in areas currently undergoing urban development, particularly in the non-breeding season. We examined avian communities at 8 parks in urban (within established urban matrix; >50% built cover) and 9 parks in exurban (within adjacent grassland; 5–20% built cover) areas in Sacramento County, CA. We measured bird species and abundance, conducting five line-transect surveys per park (85 total). We investigated factors influencing avian assemblage, including local habitat features (land cover, number of trees, fruiting trees and tree species, tree height and diameter at breast height, park size, park age), and landscape features (land cover within 500 m and distance to riparian habitat). Fifty bird species, including 15 migrants, were observed. Total species richness and abundance at urban and exurban parks was not significantly different, but community assemblages differed significantly. Park area positively predicted species richness. Abundance was negatively associated with in-park percent built cover, average number of fruiting trees and landscape-scale percent water cover. Species composition changes were associated with distance to riparian habitat and landscape percent grass cover for all but one exurban park; and with tree height, DBH and park and landscape percent tree cover for urban parks. The expansion of exurban areas in many parts of the world poses a significant risk for natural habitat loss. Parks in such areas should be planned to harbor some of the displaced biodiversity.