bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron-stimulated desorption from molecular ices in the 0.15–2 keV regime
Authors: Dupuy R. , Haubner M. , Henrist B. , Fillion J.-H. , Baglin V.
Published: November 2020

Electron-stimulated desorption (ESD) of cryosorbed molecules on surfaces is a process of relevance to fields as varied as vacuum dynamics in accelerators and astrochemistry. While desorption from such molecular systems induced by keV electrons and fast ions has been extensively studied, the sub-keV electron regime is comparatively little known. We measured and quantified electron-stimulated desorption from molecular ice systems (layers of N2, CO, CO2, Ar, and H2O/D2O condensed at cryogenic temperatures) in the 150–2000 eV electron energy range. In this regime, stopping power is no longer sufficient to explain the electron energy dependence of ESD yields. We introduce the notion of desorption-relevant depth, which characterizes the transition between two energy deposition regimes near the surface. We then apply this notion to the different systems, showing how ESD in the sub-keV regime can, for example, reveal the differences in species diffusion in crystalline and porous amorphous CO2 ices.
Statistical and quantum photoionization cross sections in plasmas: Analytical approaches for any configurations including inner shells
Authors: Rosmej F. B. , Vainshtein L. A. , Astapenko V. A. , Lisitsa V. S.
Published: November 2020

Statistical models combined with the local plasma frequency approach applied to the atomic electron density are employed to study the photoionization cross-section for complex atoms. It is demonstrated that the Thomas–Fermi atom provides surprisingly good overall agreement even for complex outer-shell configurations, where quantum mechanical approaches that include electron correlations are exceedingly difficult. Quantum mechanical photoionization calculations are studied with respect to energy and nl quantum number for hydrogen-like and non-hydrogen-like atoms and ions. A generalized scaled photoionization model (GSPM) based on the simultaneous introduction of effective charges for non-H-like energies and scaling charges for the reduced energy scale allows the development of analytical formulas for all states nl. Explicit expressions for nl = 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f, and 5s are obtained. Application to H-like and non-H-like atoms and ions and to neutral atoms demonstrates the universality of the scaled analytical approach including inner-shell photoionization. Likewise, GSPM describes the near-threshold behavior and high-energy asymptotes well. Finally, we discuss the various models and the correspondence principle along with experimental data and with respect to a good compromise between generality and precision. The results are also relevant to large-scale integrated light–matter interaction simulations, e.g., X-ray free-electron laser interactions with matter or photoionization driven by a broadband radiation field such as Planckian radiation.
A particle-based ellipsoidal statistical Bhatnagar–Gross–Krook solver with variable weights for the simulation of large density gradients in micro- and nano-nozzles
Authors: Pfeiffer M.
Published: November 2020

This paper demonstrates the efficiency of a modified particle based Ellipsoidal Statistical Bhatnagar–Gross–Krook (ESBGK) solver to simulate micro-nozzles. For this, the common particle ESBGK algorithm is adapted to handle variable particle weights including the creation of additional particles in regions with low statistical samples and merging of particles in dense regions. After the description of the methods and their implementation, the simulation results of a micro-nozzle geometry using the Direct Simulation Monte Carlo, the common particle ESBGK, and the proposed modified ESBGK method are compared concerning accuracy and efficiency. All three methods show good agreement; however, the modified ESBGK method has the highest efficiency, saving a factor of around 500 of computational time to produce a comparable statistical sample size in the rarefied expansion region.
Floating of solid non-magnetic bodies in magnetic fluids: Comprehensive analysis in the framework of inductive approach
Authors: Ivanov Aleksey S. , Pshenichnikov Alexandr F. , Khokhryakova Christina A.
Published: November 2020

This paper presents a study of the ponderomotive force acting on a solid non-magnetic sphere immersed in a magnetic fluid cylindrical container magnetized by an external homogeneous magnetic field. The problem has been studied experimentally, numerically, and analytically. The analytical study was carried out in the framework of the inductive approach, which made it possible to take into account the demagnetizing fields generated by both the magnetic fluid and the non-magnetic body. All methods of investigation used in this work showed the same non-standard force behavior with two extrema. The existence of the non-monotonous force is explained by the competition between two mechanisms: the inhomogeneous demagnetizing field inside the cylindrical container and the interaction of the solid body dipole with its own mirror image. The results of numerical simulations are in quantitative agreement with the experimental data, and the analytical results are in qualitative agreement with the experimental data.
Sample shape and boundary dependence of measured transverse thermal properties
Authors: Mumford Samuel , Paul Tiffany , Kountz Erik , Kapitulnik Aharon
Published: November 2020

Despite increased interest in thermal Hall measurements for the analysis of insulating quantum materials, there remains large uncertainty in such measurements due to contact misalignment. In this paper, we propose that sample geometry and uncertain boundary conditions provide an additional source of uncertainty in the measurement of Dxy or κxy. By running simple simulations in an open source finite-element solver, we demonstrate that measured Dxy can be changed by a non-negligible fraction in samples with similar width and length. This geometric corrective factor depends on the distinction between a uniform heat flow and constant temperature boundary couplings to a bath. Sample geometry and boundary conditions can be accounted for through simulation or by using rectangular samples to make thermal Hall measurements more reliable and reproducible. Finally, we detail a contactless optical method for measuring Dxy based on an existing photothermal microscope technique. This method is insensitive to the longitudinal diffusivity pollution caused by contact misalignment.
Improving reproducibility of quantum devices with completely undoped architectures
Authors: Srinivasan A. , Farrer I. , Ritchie D. A. , Hamilton A. R.
Published: November 2020

The reproducible operation of quantum electronic devices is a key requirement for future quantum information processing and spintronics applications. Traditionally, quantum devices have been fabricated from modulation-doped heterostructures, where there is an intrinsic lack of reproducibility due to the random potential from ionized donors. Here, we show that we can greatly improve reproducibility over modulation-doped devices by using a completely undoped architecture, with superior uniformity in the confinement potential and more consistent operating voltages for both electron and hole devices. Our results demonstrate that undoped heterostructures have significant advantages over modulation doping for reproducible manufacturing of quantum devices.
Instability induced by wall deformability in sliding Couette flow
Authors: Patne Ramkarn , Shankar V.
Published: November 2020

The linear stability of “sliding Couette flow” of a Newtonian fluid through the annular gap formed by two concentric cylinders having a ratio of inner to outer cylinder radii, β, and driven by the axial motion of the inner cylinder is studied in the low Reynolds number (<1) regime. The inner wall of the outer cylinder is lined by a deformable neo-Hookean solid layer of dimensionless thickness H. This flow configuration is encountered in medical procedures such as thread-injection and angioplasty, where the inserted needle is surrounded by the deformable wall of blood vessels. In stark contrast to the configuration with rigid cylinders, we predict the existence of finite- and short-wave linear instabilities even in the creeping-flow limit, driven by the deformable nature of the outer cylinder. Interestingly, these instabilities exist for arbitrary β, and even for non-axisymmetric perturbations, in parameter regimes where the flow is stable for the configuration with a rigid outer cylinder. For the finite-wave instability, the axisymmetric mode is the most critical mode of the instability, while the non-axisymmetric mode with azimuthal wavenumber n = 4 is the critical mode for the short-wave instability. By replacing the outer rigid boundary surrounding the deformable wall by an “unrestrained” stress-free boundary, we demonstrate that the flow becomes significantly more unstable. Thus, the present study shows that sliding Couette flow with a deformable wall can be linearly unstable at an arbitrarily low Reynolds number, in direct contrast to the stability of the same configuration with a rigid cylinder.
Effect of pulsating injection and mainstream attack angle on film cooling performance of a gas turbine blade
Authors: Hosseini Baghdad Abadi Seyyed Mehdi , Zirak Saadat , Rajabi Zargarabadi Mehran
Published: November 2020

Relatively few studies have examined the effects of pulsating unsteadiness in turbine cooling blades. This unsteadiness can be a result of compressor blades and vane interaction. In addition, there is a particular lack of data of full turbine blades at various angles of attack. The effects of pulsation frequency (f = 2 Hz, 50 Hz, and 100 Hz) and the angle of attack (α = 0°, 15°, and 30°) on the film cooling effectiveness of a row film jet at the leading edge of a modified NASA C3X blade for two blowing ratios (M = 0.5 and 1.0) in comparison with the steady state experimentally investigated on pressure and suction sides of the blade and the flow field are obtained by simulation. Three-dimensional transient Reynolds-averaged Navier–Stokes equations coupled with the shear stress transport turbulence model (SST k − ω) are used in this research. Square waves are considered to pulse the injection air. Results show that the distribution of the instantaneous film cooling effectiveness is affected by frequency, angle of attack, blowing ratio, and curvature of the blade. With an increase in the angle of attack and the pulsing frequency, the averaged film cooling effectiveness increased. Pulsation and angle of attack have different effects on the performance of the injection jet toward the pressure and suction sides of the blade. Mixing of injection air with the mainstream at the pressure side is more than that at the suction side. Under certain conditions, the averaged film cooling effectiveness of pulsation flow is greater than the steady jet.
Shock-wave thickness influence to the light diffraction on a plane shock wave
Authors: Timokhin M. Yu. , Tikhonov M. , Mursenkova I. V. , Znamenskaya I. A.
Published: November 2020

This study is devoted to the numerical analysis of the result of light distribution after passing it through a shock wave, depending on the degree of gas rarefaction. The obtained numerical results allowed reproducing the experimental shadowgraph images obtained in our study. The range of shock wave thickness (from 0 mm to 20 mm) allowed considering the qualitative change in the light distribution on the screen during switching from the regime where the wave nature of light has the greatest influence on the distribution of light to the regime of the geometric optics approach. As a result, the criteria for the applicability of the shadowgraphy technique for the experimental description of the shock wave internal structure were obtained.
Corrigendum to: Environmental enrichment strategies for nursery piglets and efficacy for maintaining interest
Authors: de Oliveira G. F. , Caldara F. R. , Marcon A. V. , Martins R. A. , Crone C. , Garcia R. G. , Paz I. C. L. A. , Nieto V. M. O. S. , Odakura A. M. , Braz J. M.
Published: November 2020

Context
Animals in situations of stress and constant fear exhibit unwanted behaviours for production. Pigs that are afraid of humans tend to associate any management as stressful. The use of environment enrichment for pigs may help to alleviate anxiety and fear, and hence reduce unwanted behaviours during handling. However, provision of appropriate enrichment presents challenges such as the rapid loss of interest in objects by animals.

Aims
The present study evaluated the effects of different environmental enrichment strategies on the behaviour of pigs at the nursery stage, maintenance of animal interest in the enrichment objects, and their reflexes when faced with emotionally negative situations.

Methods
Piglets (n = 425) were assigned in a completely randomised design with five treatments and five replicates per treatment (17 animal per replicate). The treatments employed were: control, no enriching objects in the environment; WB, wooden box with popcorn and wood shavings; PT, objects made of plastic tubing; WB and PT concurrently; and WB or PT on alternate days. Behavioural observations were made over 10 days for 8 h each day, divided into four periods of 2 h. Piglets from enriched (n = 10) and non-enriched (n = 10) environments were subjected to three fear tests (human approach, novel object and novel arena).

Key results
No significant (P > 0.05) effect was found for the type of enrichment provided or strategy adopted (concurrent vs alternating) on the time piglets interacted with the enrichment objects. Animals kept in an environment with no stimulus had higher frequency (P P P

Conclusions
The use of enrichment objects in the rearing environment of piglets at the nursery stage reduced undesirable behaviours, suggesting reduced fear and anxiety, and may therefore improve their psychological wellbeing.

Implications
Use of enrichment objects during rearing may have implications for alleviation of chronic stress, which leads to constant release of cortisol, an immune suppressor hormone that reduces the health status of the batch and hence production indices.
Keys to innovation in animal science: genomics, big data and collaboration
Authors: Rowe James B. , van der Werf Julius , Pethick David W.
Published: November 2020

As the sophistication of genomic technologies increases and their cost continues to decrease, they are becoming routine tools in livestock breeding programs and production systems. The convergence of electronic measurement systems, cloud-based computing and fast internet enable the use of powerful decision support to help automate and manage livestock production, animal welfare and quality control. The complexity of livestock production systems, combined with the challenges of producing top-quality discretionary products for consumers, means that no single organisation has the range of expertise to support coordinated development of innovation in the relevant supply chains. Collaboration between a broad spectrum of scientists and industry partners is essential to ensure well integrated input to the design and implementation of programs to deliver improvements in efficiency, quality and profit. The need for collaboration among researchers, among research organisations and with end-users has never been more important. Collaboration brings together the skills needed to manage complex problems and enables the sharing of facilities and scarce resources within Australia and internationally. However, the most important component of effective collaboration is the early engagement of end-users to contribute to the design of programs of innovation, to ensure that investment is well targeted and that there is ownership of the problem as well as the solutions delivered through research. Although the potential benefits of effective collaboration are clear, it often takes more than logic to get individuals and organisations to work together. There needs to be a significant financial incentive combined with strong industry leadership and agreed common goals. Allocating resources to establish these foundations for effective collaboration should precede any major research and development funding initiative. The present paper argues that the new face of animal science in Australia should be structured around coordinated programs of research and development, on the basis of effective collaboration.
Small fires, frequent clouds, rugged terrain and no training data: a methodology to reconstruct fire history in complex landscapes
Authors: Fornacca Davide , Ren Guopeng , Xiao Wen
Published: November 2020

An automated burned area extraction routine that attempts to overcome the particular difficulties of remote sensing applications in complex landscapes is presented and tested in the mountainous region of northwest Yunnan, China. In particular, the lack of burned samples to use for training and testing, the rugged relief, the small size of fires and the constant presence of clouds during the rainy season heavily affecting the number of usable scenes within a year are addressed. The algorithm flows through five phases: creation of standardised difference vegetation indices time series; automatic extraction of multiclass training areas using adaptive z-score thresholds; Random Forests classification; Seeded Region Growing; and spatiotemporal clustering to form polygons representing fire events. A final database spanning the period 1987–2018 was created. Accuracy assessment of location and number of fire polygons using a stratified random sampling design showed satisfactory results with reduced omission and commission errors compared with global fire products in the same region (20 and 22% respectively). Mapping accuracy of single burned areas showed higher omission (27%) but reduced commission (13%) errors. This methodology takes a step forward towards the inclusion of regions characterised by small fires that are often poorly represented in impact assessments at the global scale.
Reply to Comment on ‘On the relationship between Atlantic meridional overturning circulation slowdown and global surface warming’
Authors: Caesar L , Rahmstorf S , Feulner G
Published: November 2020

In their comment on our paper (Caesar et al 2020 Environ. Res. Lett.
15 024003), Chen and Tung (hereafter C&T) argue that our analysis, showing that over the last decades Atlantic meridional overturning circulation (AMOC) strength and global mean surface temperature (GMST) were positively correlated, is incorrect. Their claim is mainly based on two arguments, neither of which is justified: first, C&T claim that our analysis is based on ‘established evidence’ that was only true for preindustrial conditions—this is not the case. Using data from the modern period (1947–2012), we show that the established understanding (i.e. deep-water formation in the North Atlantic cools the deep ocean and warms the surface) is correct, but our analysis is not based on this fact. Secondly, C&T claim that our results are based on a statistical analysis of only one cycle of data which was furthermore incorrectly detrended. This, too, is not true. Our conclusion that a weaker AMOC delays the current surface warming rather than enhances it, is based on several independent lines of evidence. The data we show to support this covers more than one cycle and the detrending (which was performed to avoid spurious correlations due to a common trend) does not affect our conclusion: the correlation between AMOC strength and GMST is positive. We do not claim that this is strong evidence that the two time series are in phase, but rather that this means that the two time series are not anti-correlated.
Hydromorphology of coastal zone and structure of watershed agro-food system are main determinants of coastal eutrophication
Authors: Garnier Josette , Billen Gilles , Lassaletta Luis , Vigiak Olga , Nikolaidis Nikolaos P , Grizzetti Bruna
Published: November 2020

For a number of well-documented watersheds and their adjacent coastal zones, a simplified, but generic approach was developed to explore current nutrient deliveries to their corresponding marine system, characterized by their flushing rate/residence time and morphology. An indicator of eutrophication was defined derived from both the C:N:P:Si stoichiometry of the riverine nutrient delivery and the physical features of the receiving marine bay (B_ICEP). Results show that the morphological and hydrological conditions characterizing coastal zones are the main determinants of the manifestation of eutrophication caused by an imbalance of nitrogen (and/or phosphorus) with respect to silica in the river nutrient loading. Action on the structure of the agro-food system of the upstream watershed, which determines the nitrogen losses to the hydrosystem, is identified as the most efficient control for attenuating coastal eutrophication. A comprehensive and generic concept of the systemic processes responsible for river and coastal water degradation can be achieved with a chain of nested models, describing the terrestrial agro-food system of the watershed, the river network, including the biogeochemical processes responsible for water quality, and the ecological functioning of the receiving marine area, in terms of carbon, nitrogen, phosphorus, and silica cycles. This leads to a land-to-sea continuum view, promoting interdisciplinarity and dialogue among the various scientific communities and their modeling approaches. This would also help the actors in multiple sectors (farming, fisheries, tourism, etc) and policy-makers make harmonized choices for a sustainable environment through an economically and socially viable way of life for all citizens.
Peculiarities of random walks with resetting in a one-dimensional chain
Authors: Christophorov L N
Published: November 2020

The main characteristics (stationary probability distribution and mean first passage time, MFPT) of random walks on the nodes of a (semi)infinite chain with resetting are obtained. It is shown that their dependences on the resetting rate frequency r essentially differ from those within the classical continuous diffusion model. The same is true for a finite chain in which the existence of an optimal value r
* that minimizes the MFPT becomes critically dependent on the resetting node position. As one of non-standard application of the results, the counter-intuitive effect of enzymatic reaction acceleration by increasing the rate of unproductive dissociation of the enzyme-substrate complex is explained.
Accounting unit in hybridological analysis
Authors: Zhuchenko Alexander , Rozhmina Tatiana , Melnikova Natalya
Published: November 2020

The world is dedicated to studies recombinogenesis in evolution and selection, on the variability causes of recombination and segregation parameters in hybridological analysis. The necessity of a careful choice in control unit for recombination experiment dependent on the architecture of a species reproductive system.
Chitinase production by Trichoderma viride in submerged state fermentation
Authors: Mukhammadiev Rinat , Mukhammadiev Rishat , Skvortsov Evgeny , Cheremisin Alexey , Zavriev Sergey , Gerner Angelika , Valiullin Lenar
Published: November 2020

We have identified the optimal conditions for the production of chitinolytic enzymes of T.viride in submerged state fermentation. The production of chitinase by a new strain of fungus was carried out on the basal liquid medium, containing (%) colloidal chitin 0.5, NaNO3 0.2, KH2PO4 0.1; MgSO44-7H2O 0.05 and KCl, 0.05. The activity of enzymes of the chitinase complex of the strain was evaluated using the method using dinitrosalicylic acid (DNS reagent). A quantitative determination of the activity of chitinases in a producer microorganism was established by their ability to hydrolyze 0.2% colloidal chitin (in phosphate buffer 0.05 M, pH 5.2), by the content of reducing sugars formed in this process, which were evaluated using a DNS reagent. The results of studies of the influence of various cultivation parameters showed that highest chitinolotic enzymes production by T.viride was obtained at pH 4.0, (301.15-303.15) K and after 144 h growth. The studied soil isolate can be further used in biotechnological research, as well as for biological control of pests and pathogens of agricultural crops.
Digital methods for agro-monitoring and nutrient load management in the Russian part of the Baltic Sea catchment area
Authors: Briukhanov Aleksandr , Dorokhov Alexey , Shalavina Ekaterina , Trifanov Alexey , Vorobyeva Ekaterina , Vasilev Eduard
Published: November 2020

The article describes the basic requirements for an interactive programme designed for agro-monitoring and nutrient load management in the Russian part of the Baltic Sea catchment area within the borders of the Leningrad Region. The programme will monitor the farm generation of nutrients (nitrogen and phosphorus) in the organic fertilisers and create the logistical scheme of their application with due account for environmental and economic factors. The functional objectives of the interactive programme are to receive the relevant source information on the region, agricultural organisations, applied animal/poultry manure handling technologies, and manure storage types; to visualize all agricultural organizations on a digital map: location, name, specialisation, animal stock, available agricultural land; to calculate and display the current situation in agricultural enterprises: amount of organic fertiliser received, land sufficiency for all organic fertiliser application, and required volume of manure storages and composting pads; to calculate and display the forecast situation in agricultural organizations and to create the electronic passports of farms, districts and the whole Leningrad Region including the logistics of organic fertilisers distribution from supplier farms to consumer farms considering the nutrient load standards and the data on the nutrient load distribution within the boundaries of agricultural lands in the catchment area.
Transition to the circular economy and new circular business models – an in-depth study of the whey recycling
Authors: Uvarova Inga , Atstaja Dzintra , Grinbergs Ugis , Petersons Janis , Gegere-Zetterstroma Astrida , Kraze Sandra
Published: November 2020

Depleting natural resources and large amounts of waste increase the environmental pressure affecting the economy and humans. Emerging sustainability challenges require new behavioural patterns from both the business and consumers. Responding to these constraints, the circular economy is promoted as a new way towards a sustainable future. While the circular economy provides new principles for improving resource efficiency and reducing waste, most of companies run traditional business models with the perception that competitive advantages can be achieved by increasing production. Instead circular business models seek for increase of profitability and efficiency through adapting various business model innovations. However, their adoption process and results are unclear for many industries highlighting the topicality of this article. This research shows that milk processing companies lack an experience and understanding of benefits and challenges of circular business models. In milk processing, the whey is considered as problematic waste or the production leftover, which requires new treatment. The research provides analyses of the whey recycling circular business models that ensured new revenue streams, higher profitability, return on assets and competitive advantages for milk processing companies. The COVID19 pandemia increases the importance of this issue as the dairy industry due to livestock requirements shall ensure business continuity despite a crises or other risks that slowdown the business.
Engineered MSW landfills as a future material resource and a sink for long-term storage of organic carbon
Authors: Bramryd Torleif , Johansson Michael
Published: November 2020

A controlled, highly engineered landfill has many similarities to natural peatlands or other natural anoxic sediment deposits. In anaerobic MSW landfills, generally about 30-50 percent of the total carbon content in the waste can be converted into biogas and be collected as resource for energy or chemical industry. Remaining long-lived organic carbon, e.g. from lignin remains un-degraded, Organic carbon in fossil derived hydrocarbons, like plastics, will remain rather unaffected in the landfill. In a future with less remaining oil resources, landfill mining of these polymers can be valuable, making the landfill to a future “resource bank”. New reactor cell landfill technologies have shown that up to over 90 % of the produced biogas can be collected and used. Approximately 150-250 m3 of biogas per tonne waste can be extracted from a landfill reactor-cell over a 10-year period. Sequestration of a long-lived organic fraction in a landfill, with an annual input of 100 000 tons of waste, can compensate for annual CO2 emissions from about 20 000 to 25 000 cars. If more than about 60 % of produced biogas can be collected from the landfill, it has positive net effects on climate change. If the waste instead would have been incinerated this would lead to major emissions of fossil CO2, as about 30-50 % of the CO2 in the stack gasses from a waste incinerator has fossil origin.
Environmental monitoring of natural waters in the zone of impact of an enterprise producing explosives
Authors: Patokin Dmitry , Danilov Alexander , Isakov Alexander
Published: November 2020

Production of explosives, as part of chemical industry, has a significant anthropogenic impact on components of environment. The greatest negative impact due to water requirements of the industry enterprises have on hydrosphere. Generally pollutants of this group of enterprises are nitroesters – one of the most important components of products that determine energy properties of powders. In article considers the need for water quality monitoring of water bodies located in zone of influence of enterprises for contamination with nitroesters, in particular nitroglycerine (1,2,3-trinitrooxypropane). As a rule, such enterprises are located on the largest water bodies. Low solubility of the substance in water determines its risk to aquatic organisms and population. The Kama river was selected as the water object of the research in area of impact of the gunpowder production enterprise on territory of a large industrial and residential agglomeration of Perm. According to the results of environmental monitoring, which consisted in sewage and natural water, a significant excess of maximum permissible concentration of nitroglycerin in natural waters was detected, which is unacceptable for water bodies of the highest fishing category of water consumption. To reduce the anthropogenic impact on the water body, it is proposed to introduce a system for wastewater treatment from the source pollutant by ozonation of industrial wastewater with introduction of an alkaline reagent. The revealed high efficiency of the method of wastewater treatment to the content of nitroester at level of trace concentrations makes it possible to exclude the impact of the enterprise on the watercourse.
Changes of optical density and fluorescence intensity of river water samples during storage
Authors: Andrianova Maria , Bondarenko Ekaterina
Published: November 2020

Waters of river Okhta and its tributary polluted with domestic wastewater were studied during several weeks of water storage at 20°C and 8°C. At sampling day, concentrations of total organic carbon in waters were close (17-24 mgTOC/L), polluted waters had difference in electric conductivity, increased concentration of total nitrogen (TN) and NH4
+. During storage, concentrations of TOC, inorganic carbon, TN, NH4
+ declined, and the decline was stronger in polluted waters and at room temperature of storage. Spectra of optical density (D) of waters showed no significant qualitative difference between polluted and not polluted waters. During storage, D254 of all samples decreased up to 40% in 12 days. Polluted water had higher fluorescence intensity (I) at emission wavelengths 320-370 nm (up to 200%) and 420 nm (up to 50%). During storage of polluted water I decreased at 320, 350, 370 nm and increased at 420 nm. For pollution detection in not diluted waters at the sampling day and after 2 weeks of water storage the following parameters can be recommended: I230,350, I230,370 or I270,350 together with ratio of protein-like to humic-like fluorescence I230, 350/420 or I270, 350/420. These parameters can be used with or without correction of I for D.
Epitaxial GaN layers synthesized on Si (111)
Authors: Lubyankina Ekaterina , Bayramov Farid , Toporov Vladimir , Mizerov Andrei , Timoshnev Sergei , Shubina Ksenia , Rud Yury , Bairamov Bakhysh , Bouravleuv Aleksei
Published: November 2020

Realization of epitaxial synthesis of high quality gallium nitride layers on silicon substrates is driven by the high potential of GaN-on-silicon technology for fabrication of high efficiency and relatively low-cost electronic devises. Growth process of GaN layers on Si substrates by molecular-beam epitaxy is complicated by differences in thermal expansion coefficients and lattice parameters causing large number of defects and dislocations. Another issue is mutual diffusion of Si and Ga. To improve the quality of GaN layers high temperature nitridation of silicon substrates was applied. We used Raman spectroscopy and Hall measurements to study the effect of nitridation. The shift of E2
H phonon mode allowed to calculate biaxial stress and this indicated stress relaxation in GaN epitaxial layers. P-type conductivity was observed in GaN/Si(111) structures and nitridation was proven to reduce carrier concentration. Thus, high temperature nitridation of Si substrate led to stress relaxation and decrease of Ga diffusion into substrate.
The method of radiation control of water areas deep parts and bottom sediments
Authors: Gryaznova Ekaterina , Dmitrieva Diana , Pilipova Valeria , Meshalkin Valeriy , Zhuchenko Alexander , Druzhinina Galina , Bogun Inna
Published: November 2020

The article substantiates the need to control the underwater water area and bottom sediments in marine water areas, lakes and rivers. Especially in cases where hazardous facilities are located next to them (nuclear power plants, production using radioactive components, storage facilities, etc.). For various reasons, small radioactive releases occur from these facilities. The radioactive substances fall into the water and are deposited in bottom sediments. Gradually, the expositional irradiation dose in the bottom sediment increases. Sea, lake or river inhabitants begin to get sick. It is extremely difficult to establish a high level of radiation in the bottom sediment by measuring the exposure dose over the water surface. The bottom sediments may be washed ashore during water movement or various cyclones. Further, then are dispersed by wind. This can lead to radioactive damage to people, animals and territory. The methodology for the radioactive state research of the water areas deep parts and bottom sediments using an autonomous deep-sea apparatus is presented. The apparatus is equipped with sensors for measuring the expositional irradiation dose, a video camera for monitoring the bottom, a depth sensor and an echo probe to determine its coordinates under water. The using an autonomous apparatus allows to determine the presence of radioactive contamination in bottom sediments and determine the configuration of their location. This allows to plan and effectively carry out work on the cleaning of rivers, lakes and coastal zones of the seas from radioactive bottom sediments.
Research on Operation and Construction of the Development Model of “Gas Extraction-Gas Power Generation-Sales” in Small Coal Mine
Authors: Changjun Lian
Published: November 2020

Aiming at the problem that a large number of small coal mines in Yunnan Province are not effectively utilized, with a small coal mine in the region as the background, a variety of methods are used to analyze and study its low-concentration gas power generation project, and it is obtained that the key to the success of a low-concentration gas power generation project in a small coal mine is the integrated technology system of gas source security under the leadership of the concept of “gas management first”. On the basis of the gas source guarantee, the low-concentration gas power generation project of this small coal mine has been running efficiently for 4 years, generating economic income of about 4032 million yuan per year, reducing the co2 of about 44.7 ten thousand tons to improve the level of coal mine safety production, and guarantee the coal mine production standards.
Low-Temperature synthesis of FeOOH Quantum Dots as Promising Electron-Transporting Layers for High-Performance Planar Perovskite Solar Cells
Authors: Chen Hui , Ren Jing , Liu Tao , Zhao Qiang , Wang Ning , Wang Jinshu
Published: November 2020

The development of a low-temperature processed electron-transporting layers (ETL) is highly desirable for high-performance planar perovskite solar cells (PSCs) toward large-scale and flexible devices, yet remains a great challenge. Herein, a low-temperature route was applied to synthesize FeOOH quantum dots (QDs) as promsing ETL for PSCs. A systematic survey of the structure, morphology and band structure was carried out, and the device performance further illustrates that the device based on FeOOH QDs ETL achieves a high efficiency of 17.3% with negligible hysteresis. Moreover, a stable current output at 0.8 V in 400 s was observed in the champion device. As a result, the low-temperature preparation of FeOOH QDs ETL and the corresponding excellent performance of PSCs present great commercial potential for future applications.
Implementation and Optimization Strategy of SG-CCTV Inspection of CPR1000 Nuclear Power Station
Authors: Li Tian , Li Cheng , Chen Yanhui , Xue Donglin
Published: November 2020

The video inspection for primary side water chamber of the steam generator (For short: SG-CCTV inspection) was an important item of nuclear island in-service inspection. According to the structure of primary side water chamber and SG-CCTV inspection equipment, implementation and management strategies of SG-CCTV inspection were introduced. From the perspective of equipment and item management, the problems during SG-CCTV implementation process were analysed. To solve those problems, suggestions for equipment improvement and item optimization management were put forward.
A method for predicting the solar photovoltaic (PV) potential in China
Authors: Chen Yunyu , Peng Yi , He Shuyu , Hou Youmin , Qin Hanshi
Published: November 2020

A reliable assessment of energy efficiency for photovoltaic system is of importance for the solar energy policy planning and industrial development. Despite extensive advances over past years, almost all economic analyses overlooked the effect of local environment on the photoelectric conversion efficiency of solar cells, therefore leading to a non-negligible error in the prediction of photovoltaic potential. In this work, we developed a unified model to evaluate the regional economics of photovoltaic system by incorporating the heat transfer in solar cell and associated environmental influences. This model significantly improves the prediction accuracy of photovoltaic potential by establishing a correlation between the regional meteorological data and solar energy generation. In particular, with a meteorological data reduction, we dramatically decrease the computational complexity for predicting the photovoltaic potential. Through a theoretical analysis with the unified model, we demonstrate that the existing price mechanism of PV electricity in China cannot fully eliminate the economic disparities in various areas owing to the neglect of environmental effect. This work not only offers new insight into the research of solar resource and related policy making, but also provides guidelines for the further development of solar power industry.
Short-term PV power prediction considering the influence of aerosol
Authors: Liu Wenjie , Zhang Jinxia , Wei Haikun , Zhang Kanjian , Fang Shixiong , Xie Liping , Ge Jian
Published: November 2020

To improve the accuracy of photovoltaic power prediction under haze weather, a short-term PV power prediction method combining the PM2.5 forecast and SVR model is proposed. The WRF-CHEM air quality model is used to realize the simulation calculation of PM2.5 concentration, combined with the historical output data of PV power plants, and based on the SVR machine learning model to build a direct mapping relationship model between multiple meteorological elements and PV output. A forecast experiment was carried out for a certain area in North China, and the results showed that the proposed method can effectively improve the accuracy of PV power forecasting under haze weather conditions, thereby providing strong support for power grid dispatch and operation.
Microstructure Design and Properties of X100 Gas Line Pipe
Authors: Qiurong Ma
Published: November 2020

The microstructure evolution process of X100 pipeline steel is analysed, and the influence of different alloy composition and accelerated cooling process on microstructure evolution is studied in this article. It is obtained that acicular ferrite microstructure can make the yield strength of steel reach 650 MPa through micro alloying and thermo-mechanical control process(TMCP) with the comprehensive reinforcement effect of grain refinement, micro-alloying element precipitates and dislocation substructure. Acicular ferrite has the characteristics of fine grain, cross distribution, large angle grain boundary and presence of sub structure and high density movable dislocation. Test results of product quality also show that X100 pipeline steel which adopts Mn-Nb-Ti component system with a small amount of Ni (V), Mo alloy addition and TMCP process has obvious characteristics of fine grain. The Matrix is consisted of granular bainite and appropriate amount of MA as dispersion phase, which makes the tensile strength reach more than 800 Mpa. At the same time, the X100 pipeline steel has the characteristics of high toughness and good weldability, which is beneficial to ensure the safe operation of high pressure natural gas pipeline.
Design of air conditioning energy saving control system based on Niagara Internet of things technology and fuzzy algorithm
Authors: Zhang Yanjie
Published: November 2020

With the development of modern science and technology, Internet of things technology is entering people’s lives. People put forward higher requirements for the comfort and convenience of life. Air conditioning can bring people cool in hot summer, but it also brings huge energy consumption. In order to meet people’s requirements for air conditioning control comfort, and to achieve the purpose of energy saving and consumption reduction, this study is based on the Niagara Internet of things technology framework, through the human body infrared sensor and calendar control schedule, temperature sensor and air conditioning controller to control the start and stop of air conditioning. At the same time, the temperature fuzzy control algorithm is used to control the cooling temperature of the air conditioner according to the room temperature, so as to realize the adaptive adjustment of the air conditioning temperature. Finally, through the presentation XML (PX) view designed in Niagara software, the remote control of air conditioning can be realized. Through the debugging of the air conditioner, the adaptive control of the air conditioner can be realized, the comfort of the control can be improved, and the energy consumption can be reduced.
Research on gas natural emission in high pressure hydraulic reaming drillings
Authors: Tang Qiang
Published: November 2020

The research on gas natural emission in high pressure hydraulic reaming drillings is carried out at Guanyinshan Coal. This antireflection technology greatly improves the efficiency of gas natural emission, and within the limit value, the efficiency is greatly related to the rate of drilling slag. This research provides a reference for the high pressure hydraulic reaming in this mine, and also for similar mines to improve the efficiency of gas natural emission and control reaming shotcreting.
Prediction of Uncontrolled Refueling Emissions from Gasoline Vehicles Based on Mathematical Models
Authors: Liu Daming , Zhong Xianglin , Li Yaqi , Zhen Xudong , Lu Shaoyun , Xue Yuanyuan
Published: November 2020

The prediction of the uncontrolled refueling vapor generation of gasoline vehicles is the basis of the refueling emission control. It is of great significance to understand the mechanism of the gasoline vapor generation during the refueling process and to develop the refueling emission control devices. In this paper, the prediction of the refueling vapor generation of gasoline vehicles under uncontrolled conditions was conducted by using the empirical models, the steady state model and the time-varying diffusion model, respectively, and the prediction results were verified with the test results. The research results showed that the time-varying diffusion model had better adaptability and prediction accuracy than the empirical model. And the more influencing factors can be considered. But the verification and correction for this model were also needed by using experimental data. The empirical models had better prediction accuracy under specific conditions. However, due to the limitations of experimental conditions, the models lacked universality, which was an inherent defect of the empirical models. The steady-state model ignored the non-uniformity of fuel vapor concentration distribution in the fuel tank, resulting in a large error in the prediction results.
Laboratory study of nitrogen/foam enhanced oil recovery from vuggy-fractured carbonate reservoirs
Authors: Yang Wang , Hongwei Fan , Quanfeng Gong , Dong Xin
Published: November 2020

Aiming at a special vuggy-fractured carbonate, the mechanism of nitrogen flooding, co-injection of water and nitrogen (CWN), water alternating gas injection (WAG) and foam flooding was studied by slate model. Experimental results showed that mechanism of nitrogen flooding was displacing attic oil, which was similar to other vuggy fractured reservoirs. While to CWN, the main mechanism was not relieve of gas channeling. It was found that gas mainly flowed through the upper hole or the upper location of hole and water mainly flowed along the lower hole or the lower location of hole. The main reason why CWN recovery was higher than nitrogen flooding was that during nitrogen flooding, nitrogen would substitute attic oil, so some oil would flow to the water channel and form remaining oil in water channel. During CWN, water flowed mainly along the water channel in previous water flooding, so remaining oil in water channel would not occur during CWN. While to WAG, it had lowest recovery. Among the previous three flooding methods, remaining oil named “sandwich oil” was found between gas and water.
Application of heterogeneous integrated energy system in urban innovation park
Authors: Wang Lu , Wang Li , Zeng ShunQi , Li Zhen , Guo ZiXuan , Zhen Yun
Published: November 2020

Heterogeneous energy system includes different energy forms such as cold, hot and electricity, among which there is a large coupling relationship. This paper discusses the main features of heterogeneous energy system, introduces the characteristics and advantages of the application of heterogeneous energy system in the park. The methods of load interaction and comprehensive configuration used in the deployment of heterogeneous energy systems are described. Taking the energy system of Guangzhou university town as an example, the composition of heterogeneous energy and its application in the park are analyzed.