bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on technical support SaaS platform of soil pollution control based on the whole process management
Authors: Chen Yuanhua , Wang Hao , Sun Tianwei
Published: June 2021

In order to improve the effect of soil pollution prevention and control, a technical-support cloud platform is designed to establish a high-level technologies, uniform standards, and regulatory tool for soil environmental investigation, risk assessment and repair work. Firstly, according to the process of soil remediation, combined with the source and pollution characteristics of soil pollutants, the main pollution components in the soil environment were classified and distributed, and then the platform was designed and developed. The system has the functions of project management, query, risk analysis and prediction, drawing, tabulation and so on. Finally, combining with the soil environmental quality standards, the effectiveness and cost indicators of the treatment methods were classified and digitized, which would greatly improve the implementation efficiency and reduce the cost of the project management.
Experimental investigation on thermal and toxic gas hazards of typical photovoltaic modules in fire
Authors: Liao Baisheng , Yang Lizhong , Ju Xiaoyu , Peng Yang
Published: June 2021

Considering that distributed photovoltaic systems are increasingly used in commercial buildings and residential areas, the potential safety hazards caused by building fires or photovoltaic system fires are very prominent. Photovoltaic fires have different characteristics from ordinary fires and are more difficult to extinguish immediately. The photovoltaic system itself will become an additional heat load in a fire, and the safety impact of the toxic gas released by it in densely populated areas is also very important.Based on the fire calorimetry method, this paper conducts an experimental study on the thermal hazards and toxicity hazards of typical photovoltaic panels under fire. Under different external heat radiation, several important combustion characteristic parameters of customized photovoltaic samples were investigated, such as, heat release rate, mass loss rate, total heat of combustion, etc. The instantaneous concentration of several key toxic gases was tested, and the risk was quantitatively analyzed through the FED value recommended in ISO13344:2015.
The system of multimedia technologies implementation in high school
Authors: Prostova Dina , Sosnina Natalya , Shirina Natalya
Published: June 2021

Recent research highlights the effective use of multimedia as an auxiliary strategy; it helps to easily deliver educational material to students and plays a positive role in strengthening the overall trend towards computer use in education. It is impossible to overestimate the importance of multimedia technologies in education. Multimedia technologies help simplify abstract content, allow you to differ from individual people, and allow you to coordinate diverse views from different points of view. Of course, multimedia technologies improve teaching and learning process, but this technology has a number of drawbacks that make it difficult to implement it into the higher school program. The authors of the study developed the system of MMT implementation is the educational process in high school. The system was developed according to the content of MM phenomenon based on advantages as well as eliminated disadvantages of new technologies in learning process. The definite level of financing and technical support, provided according to the State Program on Digital Economy of the Russian Federation, allows high school to organize the learning process via MMT providing a big volume of different opportunities for specific purposes. Follow the developed system allows educating digital personnel ready to work for digital economy of the region.
Neural network for identifying apple fruits on the crown of a tree
Authors: Smirnov Igor , Kutyrev Alexey , Kiktev Nikolay
Published: June 2021

To identify the fruits on the crowns of trees and count their number, a software and hardware complex (PAC) based on a technical vision system and a recurrent neural network of deep learning has been developed. The created neural network and class allocation algorithms allow the software and hardware complex to function stably in the conditions of industrial horticultural plantings, regardless of the size and interference of foliage, to determine the color of the fruit surface, to identify the presence of diseases and defects of fruits. The developed package provides digital monitoring of both photographic materials and video streams in online mode.
Application of the polygon method to analyze the differentiation of the regions of the Volga federal district by the level of e-business development
Authors: Bikeeva Marina , Sysoeva Evgeniya
Published: June 2021

The materials of the article contain an integral assessment of the level of development of e-business on the example of the regions of the Volga Federal District (VFD). As a result of calculating the private and local ranks of the values of the selected criteria, fourteen polygons of the level of e-business development were built by the number of regions in the district. The results obtained make it possible to ascertain the existence of a high degree of heterogeneity of the VFD regions in terms of the level of e-business development. The leading regions include the Republic of Tatarstan, the Perm Territory, and the Nizhny Novgorod Region. The outsider regions - the Republic of Mari El, the Republic of Mordovia and the Kirov region - are characterized by a low share of organizations that used the capabilities of the Intranet and Extranet in their activities, the lack of special software tools for managing sales of goods (works, services), limited use of software, in particular, ERP-, CRM and SCM-systems.
Application of the statistical reverse method for the lithological analysis of bituminous deposits
Authors: Yachmeneva Ekaterina
Published: June 2021

The studied deposit is located on the territory of the Republic of Tatarstan (Russia). The reservoir formation is represented by bituminous sandstone. The deposit is being developed by steam-gravity drainage (SAGD). The researchers noted that the reservoir has the variability of petrophysical parameters in thickness. The correct adjustment of the lithological model will allow us to assess the variability of the reservoir characteristics by its thickness, which can better predict its reservoir and elastic properties. The article presents the results of the modeling of the mineralogical composition of rocks and the coefficient of total porosity. Results received using the statistical reverse method of constructing a volume model. This method is based on geophysical well logging used to predict the content of rock-forming components of the studied sediments. The use of core data, in particular X-ray phase analysis, made it possible to evaluate the results of the lithological model.
Regularities of the distribution of macrozoobenthos communities in the conditions of the rivers of Central and Northern Altai as an indicator of the ecological state of water bodies
Authors: Khudyakova Nadezhda , Safonova Oksana , Vozniychuk Olga
Published: June 2021

In modern conditions of Gorny Altai, with an increase in anthropogenic load on the ecosystems of the region, it becomes important to assess environmental pollution. The state of the environment monitoring is a topical direction of science. The work analyzes the distribution and structural features of macrozoobenthos communities in the rivers of Altai. Revealed 25 species of invertebrate aquatic organisms belonging to 4 types and 6 classes. Benthic communities of 12 different water bodies of the Northern and Central Altai have been analyzed. Analysis of the studied structure of groups based on Euclidean distances for the shares of species in communities showed that they can be divided into three classes depending on the dominant species in them. The scheme based on the Jaccard index made it possible to reveal the influence of environmental factors that determine the structure of macrozoobenthos communities in Altai rivers. It was revealed that the anthropogenic factor has an indirect effect on the structure of communities of aquatic organisms; therefore, the macrofauna of aquatic organisms can be used as a primary indicator of the state of aquatic ecosystems.
Joint selection of the MCS’s and power allocation coefficients in the two-user downlink PD-NOMA system
Authors: Kryukov Yakov , Pokamestov Dmitriy , Rogozhnikov Eugeniy
Published: June 2021

Power Domain Non-Orthogonal Multiple Access (PD-NOMA) is a perspective multiplexing technique for future cellular networks. Nevertheless, it is poorly studied and not applied in the existing systems due to the complexity of PD-NOMA signal processing, resource scheduling, and power allocation. The issue is that a modulation and coding scheme (MCS) selection, including power allocation, is a cooperative procedure considering the channel state information of each multiplexed user. It can be solved by enumerating all possible multiplexing combinations but at the expense of the high computational complexity. In our work, we propose a composed table with the joint MCS’s, which can be selected by the base station (BS) for the user multiplexing in a downlink PD-NOMA system based on their signal-to-noise (SNR) ratios. It allows selecting two MCS’s with two power allocation coefficients for both users and guarantees the 10% block error rate (BLER) performance in the additive white Gaussian noise (AWGN) channel. The joint MCS selection method is based on a max-rate scheduling strategy and provides system capacity maximization ignoring fairness between users. The proposed table is given in the Appendix.
A method of counteracting Byzantine robots with a random behavior strategy during collective design-making in swarm robotic systems
Authors: Tebueva Fariza , Ryabtsev Sergey , Struchkov Igor
Published: June 2021

The active introduction of robotics swarm systems into life brings the issues of their information security up to date. Known security approaches often do not take into account the peculiarities of the implementation of swarm systems, such as collective design-making, and only consider the presence of Byzantine robots with a strategy of behavior consisting in voting against a majority when a consensus is reached. The aim of this work is to increase the security of the collective design-making process in a swarm robotics system from the imposition of false and ineffective alternatives by Byzantine robots with a random behavior strategy. It is proposed to use an approach based on the use of a distributed ledger and analysis of deviations in the process of collective design-making, which will allow identifying and isolating harmful effects. The solution to the problem of detecting Byzantine robots is based on the application of the criterion of the degree of confidence of a robot in choosing an alternative when a consensus is reached by the swarm system and is based on the assumption that the distribution of the degree of confidence of a Byzantine robot due to ignoring the parameters of the external environment and voting for random alternatives is significantly different from the behavior an ordinary robot. The elements of novelty of the presented solution include the use of the degree of confidence criterion to ensure the safety of collective design-making and the ability to take into account various strategies of behavior of Byzantine robots. The use of the presented solution makes it possible to increase the efficiency of reaching consensus by a swarm robotics system in the presence of Byzantine robots. The simulation for a swarm of 20 robots, including 5 Byzantine ones with random behavior, showed an increase in the probability of correctly reaching a consensus by 12.5%. The practical significance of the presented solutions lies in the possibility of ensuring the stability of reaching consensus by a swarm robotics system in the presence of robots with harmful behavior.
PDα-type iterative learning control with initial state learning for fractional-order systems
Authors: Liu Fen , Zhang Kejun
Published: June 2021

In order to eliminate the influence of the arbitrary initial state on the systems, open-loop and open-close-loop PDα-type fractional-order iterative learning control (FOILC) algorithms with initial state learning are proposed for a class of fractional-order linear continuous-time systems with an arbitrary initial state. In the sense of Lebesgue-p norm, the sufficient conditions for the convergence of PDα-type algorithms are disturbed in the iteration domain by taking advantage of the generalized Young inequality of convolution integral. The results demonstrate that under these novel algorithms, the convergences of the tracking error are can be guaranteed. Numerical simulations support the effectiveness and correctness of the proposed algorithms.
Research and implementation of HTAP for distributed database
Authors: Jing Changhong , Liu Wenjie , Gao Jintao , Pei Ouya
Published: June 2021

Data processing can be roughly divided into two categories, online transaction processing OLTP(on-line transaction processing) and online analytical processing OLAP(on-line analytical processing). OLTP is the main application of traditional relational databases, and it is some basic daily transaction processing, such as bank pipeline transactions and so on. OLAP is the main application of the data warehouse system, it supports some more complex data analysis operations, focuses on decision support, and provides popular and intuitive analysis results. As the amount of data processed by enterprises continues to increase, distributed databases have gradually replaced stand-alone databases and become the mainstream of applications. However, the current business supported by distributed databases is mainly based on OLTP applications, lacking OLAP implementation. This paper proposes an implementation method of HTAP for distributed database CBase, which provides an implementation method of OLAP analysis for CBase, and can easily deal with data analysis of large amounts of data.
Retrospective Evaluation of Patients with Systemic Juvenile Idiopathic Arthritis: A Single-centre Experience
Authors: Bağlan Esra , Özdel Semanur , Güngör Tülin , Çelikkaya Evra , Karakaya Deniz , Bülbül Mehmet
Published: June 2021

Objective Systemic juvenile idiopathic arthritis is one of the subtypes of juvenile idiopathic arthritis. This type of disease accounts for approximately 10–20% of all cases of juvenile idiopathic arthritis. It typically affects both sexes equally and is usually present in children under 5 years. This study aimed to evaluate the demographic and clinical features of patients who were followed up for the diagnosis of sJIA in a single centre, the treatments they received, the responses to the treatment and the course of the disease.

Methods All patients with systemic juvenile idiopathic arthritis who were evaluated at Dr Sami Ulus Maternity Child Health and Diseases Training and Research Hospital, Department of Paediatric Rheumatology, between January 2017 and January 2020 were included in this study. Descriptive features, clinical information, medications, treatment responses and long-term prognosis of patients were evaluated retrospectively.

Results The study included 40 patients. 60% (n=24) of the patients were female and 40% (n=16) were male. The diagnosis age of the patients was 7.77±4.82 years and the patients were followed up for an average of 48±41 months. All of the patients had fever at the time of diagnosis. The 3 most common clinical signs after fever were arthralgia, hepatomegaly and lymphadenopathy (65, 55 and 50%, respectively). Ten patients (32.5%) had macrophage activation syndrome at admission. No significant difference was detected between the groups with and without macrophage activation syndrome concerning age, gender and clinical findings. Leukocyte, haemoglobin, platelet and erythrocyte sedimentation rates were significantly lower in the macrophage activation syndrome group compared with the other group, and ferritin was significantly higher. The C-reactive protein value was higher in the group without macrophage activation syndrome, but the difference was not statistically significant. While all patients received corticosteroid therapy as the initial therapy, 87.5% of these patients were administered pulse methylprednisolone therapy. In the follow-up, 21 patients (52.5%) needed biological treatment. Twenty-seven patients (67.5%) had a monocyclic course, 3 patients (7.5%) had a polycyclic course and 10 patients (25%) had a persistent polyarticular course.

Conclusion Early diagnosis and treatment of systemic juvenile idiopathic arthritis are important because of the risk of developing macrophage activation syndrome – the most lethal complication. In our evaluation, it was seen that laboratory parameters could provide more guidance than clinical findings. Although steroids are the cornerstone of therapy, biological agents are effective in patients who are not responsive to steroid therapy.
Vitamin-D-Versorgung und die Gesundheit von schwangeren Frauen und Kindern bis zum Schulalter
Authors: Werken Anja , Obeid Rima
Published: June 2021

Die derzeitige Studienlage weist Unklarheiten in Bezug auf Folgen einer Vitamin-D-Unterversorgung für Mutter und Kind sowie Plasma-Referenzwerte für Vitamin D und Aufnahmeempfehlungen auf. Die vorliegende Studie untersucht auf Basis einer systematischen Suche und Metaanalyse die Evidenzlage zum Zusammenhang von mütterlichem und kindlichem Vitamin D mit bestimmten gesundheitlichen Endpunkten.
Recurrent Sphenocavernous Meningioma
Authors: Inoue Mizuho , Labib Mohamed , Yang Alexander , Youssef A. Samy
Published: June 2021

A case of a recurrent sphenocavernous meningioma is presented. The patient is a 42-year-old male who presented with an episode of transient right-sided numbness. A magnetic resonance imaging (MRI) revealed a large left sphenocavernous meningioma. The patient underwent a frontotemporal craniotomy for tumor resection. Near total resection was achieved with minimal residual in the left cavernous sinus (CS) and orbital apex. The pathology was consistent with meningioma, World Health Organization (WHO) grade I. A follow-up MRI was done 9 months after surgery and showed a growth of the residual tumor, which was treated with intensity modulated radiotherapy. Tumor growth was detected on serial imaging over a 4-year period. Surgical resection was offered. A left frontotemporal craniotomy with pretemporal transcavernous approach was performed. The bone flap was reopened and the dura was opened in a Y-shaped fashion. The roof of the optic canal was drilled off, and the falciform ligament was opened to decompress the optic nerve. The tumor was disconnected from the anterior clinoid region (the anterior clinoid process was eroded by the tumor) and reflected off the wall of the lateral CS. Tumor was adherent to the V2 fascicles (the lateral CS wall was resected in the first surgery) and was sharply dissected off. Gross total resection was achieved. The pathology was consistent with meningioma, WHO grade I. The patient had an unremarkable postoperative course without any new neurological deficits.

The link to the video can be found at: https://youtu.be/KVBVw_86JqM.
Estimation of electron density and temperature in an argon rotating gliding arc using optical and electrical measurements
Authors: J Ananthanarasimhan , Gangwar Reetesh Kumar , Leelesh P. , Srikar P. S. N. S. R. , Shivapuji Anand M. , Rao Lakshminarayana
Published: June 2021

This work reports average electron temperature (Te) and electron density (ne) of an atmospheric argon rotating gliding arc (RGA), operated in glow-type mode, under transitional and turbulent flows. Both Te and ne were calculated near the shortest (δ) and longest (Δ) gap between the electrodes, by two different methods using two separate measurements: (1) optical emission spectroscopy (OES) and (2) physical–electrical. Te calculated from (a) collisional radiative model (CRM) (OES) and (b) BOLSIG+ [physical–electrical, reduced electric field (ENo) as input], differed each other by 16%–26% at δ and 6% at Δ. Te was maximum at δ (>2 eV) and minimum near Δ (1.6–1.7 eV). Similarly, the ENo was maximum near the δ (5–8 Td) and minimum near Δ, reaching an asymptotic value (1 Td). By benchmarking Te from CRM, the expected ENo near δ was corrected to 3 Td. The calculated CRM intensity agreed well with that of the measured for most of the emission lines indicating a well optimized model. The average ne near δ and Δ from Stark broadening (OES) was 4.8–8.0×1021 m−3, which is an order higher than the ne calculated through current density (physical–electrical). Te and ne were not affected by gas flow, attributed to the glow-type mode operation. To the best of authors’ knowledge, this work reports for the first time (a) an optimized CRM for RGAs (fine-structure resolved), (b) the poly-diagnostic approach to estimate plasma parameters, and (c) the validation of ENo calculated using physical–electrical measurements.
Reduce and refine: Plasma treated water vs conventional disinfectants for conveyor-belt cleaning in sustainable food-production lines
Authors: Weihe Thomas , Schnabel Uta , Winter Hauke , Möller Timon , Stachowiak Jörg , Neumann Sabine , Schlüter Oliver , Ehlbeck Jörg
Published: June 2021

Sustainable and microbiologically secure foodstuff production lines are of increasing scientific interest and are in the focus of recent research programs. Additionally, they are of great importance for the production industry due to the prevention of food-borne illnesses caused by pathogens such as Salmonella sp., Listeria monocytogenes, or Escherichia coli. These pathogens are responsible for production losses, loss of customer acceptance, and severe food-borne illnesses. A pathogenic threat is frequently combated with sanitizing steps of the production lines. For conveyor band cleaning, this study compares the cleaning abilities of nitric acid (HNO3) and plasma treated water (PTW), which have been sprayed via a commercially available nozzle on two different polymeric surfaces (polysiloxane and polyurethane). Additionally, the cleaning agents HNO3 and PTW have been characterized through their pH and their conductivity. These findings have been underpinned by experiments that focus on a possible influence of nozzle abrasion, such as brass and stainless-steel nanoparticles, on the antimicrobial potential of PTW and HNO3. Adversely acting effects like an enhanced abrasion of conveyer band materials due to PTW or HNO3 treatment have been checked by using light microscopic micrographs and topographic scans in high-resolution mode. Based on the presented results of the experiments, the suitability of an in-place sanitation step in foodstuff production lines has been demonstrated on a laboratory scale.
Impact of bulk viscosity on flow morphology of shock-accelerated cylindrical light bubble in diatomic and polyatomic gases
Authors: Singh Satyvir , Battiato Marco , Myong R. S.
Published: June 2021

Shock-accelerated bubbles have long been an intriguing topic for understanding the fundamental physics of turbulence generation and mixing caused by the Richtmyer–Meshkov instability. In this study, the impact of bulk viscosity on the flow morphology of a shock-accelerated cylindrical light bubble in diatomic and polyatomic gases is investigated numerically. An explicit mixed-type modal discontinuous Galerkin scheme with uniform meshes is employed to solve a two-dimensional system of unsteady physical conservation laws derived rigorously from the Boltzmann–Curtiss kinetic equations. We also derive a new complete viscous compressible vorticity transport equation including the bulk viscosity. The numerical results show that, during the interaction between a planar shock wave and a cylindrical light bubble, the bulk viscosity associated with the viscous excess normal stress in diatomic and polyatomic gases plays an important role. The diatomic and polyatomic gases cause significant changes in flow morphology, resulting in complex wave patterns, vorticity generation, vortex formation, and bubble deformation. In contrast to monatomic gases, diatomic and polyatomic gases produce larger rolled-up vortex chains, various inward jet formations, and large mixing zones with strong, large-scale expansion. The effects of diatomic and polyatomic gases are explored in detail through phenomena such as the vorticity generation, degree of nonequilibrium, enstrophy, and dissipation rate. Furthermore, the evolution of the shock trajectories and interface features is investigated. Finally, the effects of bulk viscosity on the flow physics of shock-accelerated cylindrical light bubble are comprehensively analyzed.
A discrete interaction model/quantum mechanical method for simulating surface-enhanced Raman spectroscopy in solution
Authors: Becca Jeffrey C. , Chen Xing , Jensen Lasse
Published: June 2021

Since surface-enhanced Raman scattering (SERS) is of considerable interest for sensing applications in aqueous solution, the role that solvent plays in the spectroscopy must be understood. However, these efforts are hindered due to a lack of simulation approaches for modeling solvent effects in SERS. In this work, we present an atomistic electrodynamics-quantum mechanical method to simulate SERS in aqueous solution based on the discrete interaction model/quantum mechanical method. This method combines an atomistic electrodynamics model of the nanoparticle with a time-dependent density functional theory description of the molecule and a polarizable embedding method for the solvent. The explicit treatment of solvent molecules and nanoparticles results in a large number of polarizable dipoles that need to be considered. To reduce the computational cost, a simple cut-off based approach has been implemented to limit the number of dipoles that need to be treated without sacrificing accuracy. As a test of this method, we have studied how solvent affects the SERS of pyridine in the junction between two nanoparticles in aqueous solution. We find that the solvent leads to an enhanced SERS due to an increased local field at the position of the pyridine. We further demonstrate the importance of both image field and local field effects in determining the enhancements and the spectral signatures. Our results show the importance of describing the local environment due to the solvent molecules when modeling SERS.
A theoretical proposal of photonic crystals with gradient superconducting thicknesses for sensing applications
Authors: Hu Cai-Xing , Guo Si-Jia , Zhang Hai-Feng
Published: June 2021

In this paper, a refractive index (RI) sensor with superconducting photonic crystal in the terahertz regime is theoretically analyzed by the transfer matrix method. An asymmetric resonance cavity containing gradient thicknesses of the superconducting layer is employed to suppress the resonance absorption linewidth. We present the coupled wave theoretical model to give an optimization scheme for excellent sensing performance. The proposed sensing models can achieve an excellent single resonant peak when the temperature is over 80 K. When the incident angle varies between 50° and 70° in TE mode, the shift of a single resonant peak has a linear relationship with the incident angle. The simulation results report that the sensitivity and figure of merit in the optimal model can reach over 22.2 μm RIU−1 (RIU represents RI unit) and 265 at the ultralow temperature (85 K), respectively. Its performance indicators are dozens of times those of the traditional photonic crystal RI sensor. Our study provides theoretical guidance for the design of a low-temperature RI sensor with a high-performance indicator.
Lattice Boltzmann modeling of double-diffusive convection of dielectric liquid in rectangular cavity subjected to unipolar injection
Authors: Liang Xudan , Wang Lei , Li Dinggen , Ma Ben , He Kun
Published: June 2021

The lattice Boltzmann method is used to study the double-diffusive convection caused by the simultaneous effect of the temperature gradient and concentration gradient of the dielectric liquid in a rectangular cavity in the case of unipolar injection of ions. Considering that the physical model in this article is a complex dynamic system, we first conducted a linear stability analysis and obtained a neutral stability curve. Then we made a series of simulations to determine the influence of different dimensionless parameters on the movement of dielectric liquids and the distribution of charge density, temperature field, and concentration field. The variation range of the parameters is as follows: thermal Rayleigh number (1000≤Ra≤20000), electric Rayleigh number (100≤T≤800), Lewis number (1.0≤Le≤50.0), and buoyancy ratio (−2≤Nc≤0.5). The results show that the increase in electric Rayleigh number and thermal Rayleigh number will enhance the intensity of heat and mass transfer. Compared with pure electric convection, the existence of temperature field and concentration field have increased the instability of the dielectric fluid flow. When the Lewis number increases, the average Nusselt number will decrease but the average Sherwood number will increase. In addition, we noticed that the heat and mass transfer intensities have increased with the increase of the buoyancy ratio. When the buoyancy rate gradually increases from –2.0, we observe a bifurcation structure, and as the electric Rayleigh number increases, the critical value Ncc that causes convection will decrease.
Coherent preparation of the biexciton state in a semiconductor quantum dot coupled to a metallic nanoparticle
Authors: Paspalakis Emmanuel , Smponias Athanasios , Stefanatos Dionisis
Published: June 2021

We study the potential for controlled transfer of population to the biexciton state of a semiconductor quantum dot coupled with a metal nanoparticle, under the influence of an electromagnetic pulse with hyperbolic secant shape, and derive analytical solutions of the density matrix equations for both zero and nonzero biexciton energy shifts. These solutions lead to efficient transfer to the biexciton state for various interparticle distances including relatively small values. In certain cases, when the distance between the two particles is small, the transfer of population is strongly modified because of the influence of surface plasmons to the excitons, and the effect is more pronounced for shorter pulses. The hybrid nanostructure that we study has been proposed for generating efficient polarization-entangled photons, and thus, the successful biexciton state preparation considered here is expected to contribute in this line of research.
Tuning optical and electronic properties of 2D ZnI2/CdS heterostructure by biaxial strains for optical nanodevices: A first-principles study
Authors: Abdulameer Mohammed Jassim , Abed Al-Abbas Shurooq Sabah , Jappor Hamad Rahman
Published: June 2021

The structural and optoelectronic properties of a novel ZnI2/CdS van der Waals (vdW) heterostructure are studied under the effect of biaxial strain based on the density functional theory. Our results show that the ZnI2/CdS vdW heterostructure is dynamically and thermally stable depending on the molecular dynamics simulation and phonon dispersion curve. The results also indicate that the ZnI2/CdS heterostructure exhibits type-II band alignment with an indirect energy gap of 0.886 and 1.336 eV according to the Perdew–Burke–Ernzerhof and Heyd–Scuseria–Ernzerhof methods, respectively. Besides, the biaxial strain has a significant impact on the electronic properties. The energy bandgap of the ZnI2/CdS heterostructure decreases gradually as the compressive strain increases, reaching a minimum value of 1.162 eV at −6%. Also, a transformation from indirect bandgap to direct bandgap appears at strains of 4% and 6%. Broadly, it has been found that the optical properties of the ZnI2/CdS vdW heterostructure improve under the influence of strain, and the absorption coefficient can reach 105 cm−1 with the emergence of a shift phenomenon that expands the absorption capacity. Therefore, the application of strain will drastically improve the optical and electronic properties of the ZnI2/CdS vdW heterostructure, providing a roadmap for enhancing optical efficiency in photocatalytic and photovoltaic devices.
Propagation.
Authors: Mitra Sisir , Ray Pravat K.
Published: June 2021

This chapter deals with various propagation methods used in the multiplication of guava and progress made so far in this field. Seeds, stem cuttings, root cuttings, air layering, stooling, grafting, budding, rootstock, and in vitro propagation are discussed.
Orchard management.
Authors: Mitra Sisir , Pathak P. K.
Published: June 2021

Commercial production from a guava orchard begins on the third year after planting and cropping may continue for 40 years or more. The performance of an orchard depends on its management, which includes water and nutrient management, selection of the correct cultivars, planting technique, canopy management for flowering and fruiting, and improved light efficiency through pruning to optimize the quality of young and bearing trees. This chapter provides information on planting system, planting density, training and pruning, intercropping, and weed control in guava orchards.
Flowering.
Authors: Lin Shu-Yen , Chen Po-An
Published: June 2021

This chapter covers the various factors affecting the transformation of vegetative growth to reproductive phase of guava trees, and the phenology, anthesis and pollination in guava. The agricultural practices for regulating crop production are also discussed.
Physiological disorders.
Authors: Tajidin Nor Elliza , Mohamad Munirah , Hamidon Azimah , Hassan Hamizah , Ahmad Siti H.
Published: June 2021

Guavas are highly perishable fruits where the production and postharvest quality of guava are affected by micronutrient deficiencies that can lead to physiological disorders. Environmental variables such as temperature, light, aeration and nutritional imbalances can also result in a disturbance in the plant metabolic activities and cause physiological disorders. It is crucial to understand several technical terms which identify the physiological and nutritional disorder symptoms, especially on guava fruit; for example, bronzing, chlorosis, lesion, scorching and others. This chapter discusses primary physiological disorders, including chilling injury, external and internal browning, sunscald, bronzing, fruit drop and nutrient deficiency.
Postharvest management.
Authors: Dole John M. , Faust James E.
Published: June 2021

This chapter focuses on the main issues that need to be considered at every step in the postharvest handling system of cut flowers, i.e. temperature, water, sanitation, carbohydrates, disease and ethylene. Their impacts on the vase life and quality of various species are discussed as well as the importance of optimizing the postharvest life of cut flowers and foliage by proper cultivar selection before planting and the use of appropriate production systems.
Why make a strong muscle weaker?
Authors: Iorga Bogdan , Kraft Theresia
Published: June 2021

Iorga and Kraft discuss a recent investigation on force inhibition by mavacamten in ventricular and skeletal myofibrils.
CLIC pre-alignment — status and remaining challenges
Authors: Kemppinen Juha , Rude Vivien , Mainaud Durand Hélène , Mattila Jouni
Published: June 2021

The Compact Linear Collider (CLIC) is a study of a 3 TeV linear electron–positron (e+e−) accelerator and is a successor candidate for CERN’s Large Hadron Collider. The CLIC luminosity target is 5.9 × 1034 cm−2 s−1, which causes unprecedented pre-alignment requirements of its main linear accelerator (main linac). Along the 50 km long tunnel, the main components of any 200 m long section have to be positioned within 10 µm from a straight reference line. The pre-alignment challenge has been studied at CERN since the 1990s, and the main technical challenges have been solved. This article summarizes the positioning strategy and presents it to an audience outside the particle accelerator community. The methods can be of interest especially in the field of large-scale metrology. The positioning strategy consists of several steps or subsystems. The development of a straight reference line over tens of kilometers allows absolute positioning of accelerator components, while a process called fiducialization defines component reference axes with regard to alignment targets. Emphasis is on a support pre-alignment network that acts as a link between the straight reference line and fiducialization. The subsystems and remaining challenges in their development are presented. The chosen strategy’s potential is demonstrated experimentally by building a short test setup.
Tungsten boride shields in a spherical tokamak fusion power plant
Authors: Windsor Colin G. , Astbury Jack O. , Davidson James J. , McFadzean Charles J.R. , Morgan J. Guy , Wilson Christopher L. , Humphry-Baker Samuel A.
Published: June 2021

The favourable properties of tungsten borides for shielding the central high temperature superconductor (HTS) core of a spherical tokamak fusion power plant are modelled using the MCNP code. The objectives are to minimize the power deposition into the cooled HTS core, and to keep HTS radiation damage to acceptable levels by limiting the neutron and gamma fluxes. The shield materials compared are W2B, WB, W2B5 and WB4 along with a reactively sintered boride B0.329C0.074Cr0.024Fe0.274W0.299, monolithic W and WC. Five shield thicknesses between 253 and 670 mm were considered, corresponding to plasma major radii between 1400 and 2200 mm. W2B5 gave the most favourable results with a factor of ∼10 or greater reduction in neutron flux and gamma energy deposition as compared to monolithic W. These results are compared with layered water-cooled shields, giving the result that the monolithic shields, with moderating boron, gave comparable neutron flux and power deposition, and (in the case of W2B5) even better performance. Good performance without water-coolant has advantages from a reactor safety perspective due to the risks associated with radio-activation of oxygen. 10B isotope concentrations between 0% and 100% are considered for the boride shields. The naturally occurring 20% fraction gave much lower energy depositions than the 0% fraction, but the improvement largely saturated beyond 40%. Thermophysical properties of the candidate materials are discussed, in particular the thermal strain. To our knowledge, the performance of W2B5 is unrivalled by other monolithic shielding materials. This is partly as its trigonal crystal structure gives it higher atomic density compared with other borides. It is also suggested that its high performance depends on it having just high enough 10B content to maintain a constant neutron energy spectrum across the shield.
Coordinated target tracking of two UAVs based on game theory approach and Lyapunov guidance vector fields
Authors: Shi Hanran , Lu Faxing , Qi Jiangxin , He Haotian
Published: June 2021

Considering the problems of the lack of tracking the intelligent target, which is “smart” enough to escape from the detection by maximizing the estimation error in the current tracking methods by multi-UAVs, a cooperative control method for tracking intelligent target by two UAVs is proposed based on Lyapunov guidance vector field. The mathematical model of an intelligent target is established. According to the multi-UAV distributed intelligent target state fusion estimation method, the target state information is obtained to control two UAVs to circle the target through the Lyapunov guidance vector method. The simulation results demonstrated that the method enables two UAVs to track the intelligent target stably and improve the intelligent target’s positioning accuracy effectively
Transient modelling and simulation of the forced arc extinguish period of the circuit breakers
Authors: Chen Daopin , Xie Zhiyang , Wang Zhenxing , Cao Zhiyuan , Yan Jing
Published: June 2021

Plasma transport during continuous extinction processes from high-current arcs to fully extinction is an important issue in the study of vacuum arcs. In this research a 3D hybrid plasma model has been developed to study the extinguish period of the DC vacuum arc. The model treats the electrons as a massless fluid and ions as macro particles. The ion-neutral collision processes including both charge exchange collisions and momentum exchange collisions are considered with Monte-Carlo method. By this approach, the vacuum arc model consists of plasma jets ejected from multiple cathode spots is established and the behaviours of ions under the collisions with neutral atoms are simulated. It is shown that a large number of low-speed ions are generated in the interelectrode region due to the chare exchange collisions between ions and neutrals. And as the arc current drops to zero, the proportion of low-speed ions to the total ions at each moment becomes higher and higher.
Design and Implementation of the“Internet plus” Intelligent power simulation and learning system
Authors: Zhao Xiaojun , Gao Feng , Wang Geng , Shi Jiaoyang , Yang Jianmei , Sun Aichun
Published: June 2021

Aiming at the shortcomings of the existing power simulation training system, this paper proposes a design of the Internet plus intelligence power simulation and learning system based on cloud computing, artificial intelligence and adaptive learning technology. The system solves the problems of dispatching, monitoring, operation and maintenance personnel unable to use fragmented time to carry out simulation learning at any time and anywhere, can not carry out adaptive learning according to learners’ knowledge and skills, lack of guidance and evaluation system in the process of distance autonomous learning, lack of interest in the system, and can not effectively stimulate the learning interest of learners. The research results of this paper have been successfully applied in Gansu Electric Power Company, with the characteristics of convenient use, high cost performance, more intelligent and so on, and obtained good training effect.
Research on Probabilistic Power Flow Calculation of DC Distribution Network
Authors: Lin E , Yu Xiao , Zhen MA , Yongqiang Zhu
Published: June 2021

With the development of distributed power sources based on wind power and photovoltaics and the increase of DC loads, DC power grids have attracted more and more attention. Compared with the AC distribution network, the DC distribution network can save a lot of commutation links while absorbing a large amount of renewable energy and DC load, reducing losses and improving economic benefits. This paper combines the probabilistic power flow calculation method based on the three-point estimation method and the Nataf inverse transform used in the AC power grid with the DC power flow model, and proposes a method suitable for the probabilistic power flow calculation of the DC distribution network. Comparing the results and analyzing the in fluence of the load distortion rate and the increase in the capacity of new energy absorbed on the calculation error of the estimation method, it demonstrates the accuracy and effectiveness of the calculation method in this paper.
Thermodynamic study of a supercritical carbon dioxide Brayton cycle based on main compression intercooling configuration
Authors: Orjuela Abril M S , Bustos Urbano V J , Pabón León J A
Published: June 2021

This study presents detailed thermodynamic modeling of a supercritical Brayton cycle operating with carbon dioxide as a working fluid for electric power generation. The study incorporates a main compression intercooling configuration while elucidating the effect of operational parameters on the overall performance based on energy and exergy perspectives. The model was carefully validated with relevant authors. Moreover, two different optimization methodologies, namely particle swarm optimization and fmincom, are evaluated based on convergence criteria. The results demonstrated that the fmincom reduced the iteration time between 140 s - 180 s. The cycle pressure played a central role in the stability of the thermophysical properties of the working fluid. The energy and exergy efficiencies present a direct relation with the inlet temperature. The air cooling and regenerators represent the biggest contributor to exergy destruction, whereas the compressors featured minimal impact on the exergy degeneration. Overall, the proposed configuration demonstrated robust performance to implement with high-grade heat sources, especially in non-interconnected areas.
Time series and stochastic differential equations as a tool to model the volatility of an asset
Authors: Ramírez C A V , González J R , Correa G
Published: June 2021

In the problem of estimating the prices of electricity markets, different forecast models have been proposed for the short term, among the most outstanding are the works by Francisco Nogales, which uses autoregressive integrated moving average methodology to analyses time series in the California market. Peninsular Spain. Nogales and Contreras use time series models applied to the markets of California and Spain, the applied series were carried out to estimate the hourly price of the following day using two methodologies, the first a dynamic regression and the second transfer function models. In he proposes a prediction based on Autoregressive conditional heteroscedasticity models generalized conditional autoregressive heteroscedasticity Rabbit use the wavelet transform to decompose the data series, then applying an autoregressive integrated moving average model to the transformed series, taking advantage of the existing advantages in the domain of the frequency. The techniques have a high correlation with problems of physics which can be approached in a similar way, we must highlight the fact of using stochastic differential equations which are modern techniques in mathematics and physics.
Design of a proportional integral derivative controller of temperature regulated for a nursery
Authors: Perez-Torrado W , Espinel-Blanco E , Velásquez-Pérez T
Published: June 2021

This article describes the design and simulation of a proportional integral derivative PID controller that operates a proportional control valve to allow the flow of hot water to the radiant floor of a pig farm to maintain the required temperature. In the development of the project physical and mathematical concepts are required for controlling, the temperature oscillations in the range of 25 °C to 35 °C and the heat flux through the radiating surface of the floor, as well as analyzing the parameters involved for the development of the control system; In the control system design the characteristics and parameters involved in the pigs rearing by means of corral were identified; later the thermal analysis of the heating system integrated into the radiant floor that supplies heat to maintain the temperature was carried out, then the response of the temperature control system was simulated in the Scilab software and finally, the programming of the proportional integrative control was carried out. The design considers using gas generated in a biodigester to transfer thermal energy to the heating water that circulates through the floor, transferring heat to the brood module until it reaches and maintains the desired temperature using a control system that involves a proportional valve program in Arduino. The entire system was simulated by means of software including the gas and water circuits according to the heat transfer flow required to maintain the controlled temperature inside the module. The developed design allows controlling the heat flow to maintain the required temperature, stabilizing the process in 20 minutes.