bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional Evaluation of Levator Scapulae Tendon to Supraspinatus in Adult Brachial Plexus Injuries
Authors: Rayidi Venkata Koteswara Rao , R. Srikanth , Appaka Jagadish Kiran C.V.
Published: February 2021

Introduction Brachial plexus injuries are severe life-altering injuries. The surgical method to restore shoulder abduction in adult upper brachial plexus injuries involves the usage of nerve grafts and nerve transfers targeting the suprascapular and/or the axillary nerve. When the primary nerve surgery has been unsuccessful or recovery has been incomplete or with a late presentation, muscle transfer procedures are needed to provide or improve shoulder abduction. Levator scapulae to supraspinatus is a transfer to improve shoulder abduction in posttraumatic brachial plexus injuries.

Material and Methods The study included 13 patients with the age ranging from 17 to 47 years with a mean age of 30 years. All these patients had preop shoulder abduction of Medical Research Council (MRC) grade ≤3. All had a minimum of MRC grade 4 of active elbow flexion. Eleven patients had primary surgery. Only patients with a minimum of 1 year postoperative follow-up were included. All 13 patients underwent levator scapulae transfer only.

Results All patients had a stable shoulder postoperatively. The average increase in active shoulder abduction was from 6.15°(median: 0°) preoperatively to 61.92°(median: 60°), with an average gain in shoulder abduction of 49.61°(median: 50°).

Conclusions Transfer of levator scapulae tendon to the supraspinatus is an option to improve shoulder abduction in posttraumatic brachial plexus. In conditions where supraspinatus alone is not functioning, levator scapulae is the best available transfer, considering its strength and maintaining the form of the shoulder unlike trapezius transfer. In patients with previous surgery where supraspinatus has recovered partially but not functionally significant, this tendon transfer can be considered for the augmentation of the existing shoulder abduction.
Corona-Krise: Die nächste Pandemie wird kommen
Authors: Ekkernkamp Axel
Published: February 2021

Es ist gerade mal ein Jahr her: Ende Januar 2020 werden in Deutschland die ersten Corona-Fälle bekannt.
Krankenhaus Barometer 2020: Fast jede zweite Klinik erwartet negatives Jahresergebnis
Authors: Kucera Martin
Published: February 2021

Die Corona-Pandemie hat die ohnehin angespannte finanzielle Situation der Kliniken in Deutschland noch einmal verschärft. Zudem lehnt die große Mehrheit eine Wiedereinführung der Pflegepersonaluntergrenzen ab.
Charité-Vorstand Erweitert: Mission Forschungauf höchster Ebene
Authors: Kohrs Jens
Published: February 2021

Die Berliner Charité beruft Martin E. Kreis und Christopher Baum zu Vorständen Translationsforschungsbereich und Krankenversorgung und schließt damit die Weiterentwicklung des Führungsgremiums ab.
Manager Des Jahres 2020: Christian Drosten: Sein größter Trumpf ist Unabhängigkeit
Authors: Ullrich Kerstin
Published: February 2021

Die Corona-Pandemie brach über Deutschland herein wie eine Naturkatastrophe. Der Virologe Professor Dr. med. Christian Drosten stellt seine Expertise zur Verfügung, um das Land durch die Krise zu navigieren – als Politikberater, Wissenschaftler und Kommunikator. Über Nacht wird er zum Prominenten und für manche zur Reizfigur. Rückblick auf ein Ausnahmejahr im Leben eines Forschers, der die Herausforderungen auf eigene Weise meistert.
Corona Reloaded: Gut vorbereitet in der zweiten Welle
Authors: Thalmayr Maria
Published: February 2021

Obgleich das Gesundheitswesen an der Belastungsgrenze agiert(e) – auf die zweite, wesentlich „höhere“ Welle der Corona-Pandemie waren alle Einrichtungen gut vorbereitet. Der Routinebetrieb konnte weitgehend weiterlaufen – ein klares Indiz für die enorme Anpassungs- und Lernfähigkeit des Gesundheitswesens.
DGIV Nachrichten: Integrierte Versorgung – bislang eine Geschichte verpasster Gelegenheiten
Authors: Kloepfer Albrecht
Published: February 2021

Schon in unserem letzten Beitrag haben wir die Bilanz von Jens Spahn in Bezug auf integrierte Versorgung angerissen – doch wo genau läuft es schief in der Maschinerie? Was wäre möglich gewesen, und welche systemimmanenten Widerstände sind zu überwinden? Es lohnt ein Blick in die jüngste Geschichte des SGB V.
CSR reporting in China’s private and state-owned enterprises: A mixed methods comparative analysis
Authors: Ervits Irina
Published: February 2021

The paper pursues a mixed methods approach of conducting both quantitative and qualitative content analysis of corporate social responsibility (CSR) reports in two types of Chinese companies: State-owned (SOE) and non-state-owned (non-SOE) enterprises. Quantitative content analysis revealed overall homogeneity in CSR reporting among SOEs and non-SOEs in China, which can be explained by coercive isomorphism on a national scale. The Chinese government has created an intricate system of incentives encouraging both SOEs and non-SOEs to engage in socially responsive behavior and disclosure. As a result of qualitative analysis, a recurring theme of “strategic emerging industries” (SEI) was identified in the CSR reports of predominantly state-owned banks. This finding provides empirical evidence of the link between the social and economic objectives of the Chinese government, and it shows how state-owned banks mediate between the state and business (SOEs and non-SOEs) as part of a coercive isomorphism apparatus.
Polynomial tau-functions of the KP, BKP, and the s-component KP hierarchies
Authors: Kac Victor G. , Rozhkovskaya Natasha , van de Leur Johan
Published: February 2021

We show that any polynomial tau-function of the s-component KP and the BKP hierarchies can be interpreted as a zero-mode of an appropriate combinatorial generating function. As an application, we obtain explicit formulas for all polynomial tau-functions of these hierarchies in terms of Schur polynomials and Q-Schur polynomials, respectively. We also obtain formulas for polynomial tau-functions of the reductions of the s-component KP hierarchy associated with partitions in s parts.
A continuous flow liquid propellant strand burner for high pressure monopropellant and bipropellant combustion studies
Authors: Fuller Casey C. , Sinrud Joshua B. , Schwind Rachel A. , Klassen Michael S. , Goldsmith C. Franklin , Walker Robert A.
Published: February 2021

A combustion assembly capable of continuously burning monopropellant and bipropellant liquid fuels at pressures up to 80 bars (1145 psig) was designed and constructed. The assembly is based on a liquid propellant strand burner where a manifold maintains small positive differential pressures on the fuel to maintain a steady supply into the reaction vessel. Optical ports enable direct visualization of the flame and will allow for future spectroscopic and imaging studies of the flame. The strand burner design was tested using nitromethane with both air and inert environments in the reaction vessel. Continuous combustion was sustained for almost 8 min in air (34 bars/500 psig) and more than 6 min in N2 (70 bars/1000 psig). A unique outcome from the initial testing of this device is the ability to ignite liquid nitromethane in an inert environment without the use of a pilot flame started in air.
Short term wind energy resource prediction using WRF model for a location in western part of Turkey
Authors: Tan Elcin , Mentes S. Sibel , Unal Emel , Unal Yurdanur , Efe Bahtiyar , Barutcu Burak , Onol Baris , Topcu H. Sema , Incecik Selahattin
Published: February 2021

Wind energy is a rapidly growing industry in Turkey. Wind power potential studies revealed that the most promising region for electricity generation is the western part of Turkey. Wind speed forecasting is necessary for power systems because of the intermittent nature of wind. Thus, accurate forecasting of wind power is recognized as a major contribution to reliable wind power integration. This paper assesses the performance of the weather research forecasting (WRF) model for wind speed and wind direction predictions up to 72 h ahead. The wind speeds and wind directions are evaluated based on the mean absolute error (MAE). Evaluations were also performed seasonally. Moreover, in order to improve the WRF simulations, a multi-input–single output artificial neural network (ANN) approach is applied to both wind speeds of the WRF model and wind power estimates, which are estimated from the wind speeds of the WRF model by using a power curve for the Soma wind power plant. Traditional error metrics were used for validations using wind tower mast data installed nearby the wind farm. The results from up to 72 h forecast horizon show that the WRF model slightly overpredicts the wind speeds. Wind speed predictions by the WRF model are found highly depending on the season, location, and wind direction. The model is also able to reproduce wind directions except for low wind speeds. Large MAEs are found for the winds less than 5 m/s. The performance of the WRF model for wind power prediction decreases with the increasing runtime. Root mean square error and normalized root mean square error (nRMSE) in wind powers range in between 123–261 kW and 13%–32% without performing the ANN approach, respectively. The improvement of the ANN depends on the forecast horizon, season, and location of turbine groups, as well as its application on either the wind speed outputs of the WRF model or wind power estimations. The ANN significantly improves the WRF at large forecast horizons for wind power estimations, for which it gives better results in the summer and reaches 29% improvement for summer on average for nRMSE. On the other hand, ANN adjusts the wind speed outputs of the model better than that of wind power estimations. For instance, the nRMSE is approximately 13% for 24 h winter wind speed simulations of the WRF for the turbine groups G1 and G4, after ANN adjustment. The ANN improves the results better for turbine group 1, because of less complexity of this group in the direction of prevailing wind. The evaluation of the ANN suggests that the approach can be used for improving the performance of the wind power forecast for this power plant.
Biomaterials-based formulations and surfaces to combat viral infectious diseases
Authors: Kumari Sushma , Chatterjee Kaushik
Published: February 2021

Rapidly growing viral infections are potent risks to public health worldwide. Accessible virus-specific antiviral vaccines and drugs are therapeutically inert to emerging viruses, such as Zika, Ebola, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Therefore, discovering ways to prevent and control viral infections is among the foremost medical challenge of our time. Recently, innovative technologies are emerging that involve the development of new biomaterial-based formulations and surfaces endowed with broad-spectrum antiviral properties. Here, we review emerging biomaterials technologies for controlling viral infections. Relevant advances in biomaterials employed with nanotechnology to inactivate viruses or to inhibit virus replication and further their translation in safe and effective antiviral formulations in clinical trials are discussed. We have included antiviral approaches based on both organic and inorganic nanoparticles (NPs), which offer many advantages over molecular medicine. An insight into the development of immunomodulatory scaffolds in designing new platforms for personalized vaccines is also considered. Substantial research on natural products and herbal medicines and their potential in novel antiviral drugs are discussed. Furthermore, to control contagious viral infections, i.e., to reduce the viral load on surfaces, current strategies focusing on biomimetic anti-adhesive surfaces through nanostructured topography and hydrophobic surface modification techniques are introduced. Biomaterial surfaces functionalized with antimicrobial polymers and nanoparticles against viral infections are also discussed. We recognize the importance of research on antiviral biomaterials and present potential strategies for future directions in applying these biomaterial-based approaches to control viral infections and SARS-CoV-2.
Semi-algebraic sets method in PDE and mathematical physics
Authors: Wang W.-M.
Published: February 2021

This paper surveys recent progress in the analysis of nonlinear partial differential equations using Anderson localization and semi-algebraic sets method. We discuss the application of these tools from linear analysis to nonlinear equations such as the nonlinear Schrödinger equations, the nonlinear Klein–Gordon equations (nonlinear wave equations), and the nonlinear random Schrödinger equations on the lattice. We also review the related linear time-dependent problems.
Derivation of the nonlinear Schrödinger equation with a general nonlinearity and Gross–Pitaevskii hierarchy in one and two dimensions
Authors: Li Yongsheng , Yao Fangyan
Published: February 2021

In this paper, we investigate the quantum many-body dynamics with a linear combination of many-body interactions. We derive rigorously the nonlinear Schrödinger equation with a general nonlinearity as the mean-field limit of this model. Due to the complex interaction structure, we establish a new energy estimate for 0<β<1(m−1)d, which is efficient to handle the case of many-body interactions and allows us to obtain the mean-field approximation on longer length scales than the previous result in the work of Xie [Differ. Integr. Equations 28, 455–504 (2015)].
Enhanced air stability of superhydrophobic surfaces with flexible overhangs of re-entrant structures
Authors: Choi Woorak , Kang Minsu , Park Joo Young , Jeong Hoon Eui , Lee Sang Joon
Published: February 2021

The stability of air plastron entrapped in a submerged superhydrophobic (SHPo) surface determines the sustainability of the surface properties including drag reduction, self-cleaning, and anti-icing. To increase the stability for high water pressure, various microstructures have been adopted for SHPo surfaces. A re-entrant structure is a typical example to provide high stability for air plastrons. This work proposes flexible overhangs of the re-entrant structures as a new strategy for additional stability. Several SHPo surfaces with re-entrant structures of different sizes are fabricated, and their Young's moduli (E) are controlled from 715.3 kPa to 2509 kPa. Pressurization of water and air diffusion from the plastrons to the surrounding water cause deformation of the air–water meniscus until air plastron disruption starts to occur. The critical water pressure for air plastron disruption is gradually increased as the E of the overhangs decreases. The critical value is also increased as the gap distance between the adjacent overhangs increases. When the water pressure is less than the critical value, the air plastron is also gradually disrupted by the air diffusion. The lifetime elapsed to the air disruption increases by 19%–44% as the value of E decreases. The present results would pave the way for utilizing flexible overhangs of re-entrant structures as a novel approach for increasing the air stability of SHPo surfaces.
Energy exchange rate coefficients from vibrational inelastic O2(Σg−3) + O2(Σg−3) collisions on a new spin-averaged potential energy surface
Authors: Hong Qizhen , Sun Quanhua , Pirani Fernando , Valentín-Rodríguez Mónica A. , Hernández-Lamoneda Ramón , Coletti Cecilia , Hernández Marta I. , Bartolomei Massimiliano
Published: February 2021

A new spin-averaged potential energy surface (PES) for non-reactive O2(Σg−3) + O2(Σg−3) collisions is presented. The potential is formulated analytically according to the nature of the principal interaction components, with the main van der Waals contribution described through the improved Lennard-Jones model. All the parameters involved in the formulation, having a physical meaning, have been modulated in restricted variation ranges, exploiting a combined analysis of experimental and ab initio reference data. The new PES is shown to be able to reproduce a wealth of different physical properties, ranging from the second virial coefficients to transport properties (shear viscosity and thermal conductivity) and rate coefficients for inelastic scattering collisions. Rate coefficients for the vibrational inelastic processes of O2, including both vibration-to-vibration (V–V) and vibration-to-translation/rotation (V–T/R) energy exchanges, were then calculated on this PES using a mixed quantum–classical method. The effective formulation of the potential and its combination with an efficient, yet accurate, nuclear dynamics treatment allowed for the determination of a large database of V–V and V–T/R energy transfer rate coefficients in a wide temperature range.
Effect of plastic straining on the remanent magnetization of ferritic-pearlitic steel: Experimental and modeling aspects
Authors: Maazaz Z. , Hubert O. , Fnaiech E. Amira , Kassir L.
Published: February 2021

The remanent magnetization of a carbon steel which has been plastically deformed by uniaxial tensile test at different strain levels is measured along the tensile direction during unloading and at the unloaded state. It is shown that plastic strain considerably reduces the remanent magnetization but that remanence is recovered under applied stress, leading to the conclusion that behavior of the deformed material seems to be able to be obtained by a simple translation in the stress space of the behavior at the undeformed state. This result is in accordance with the results of a modeling approach considering the deformed material as a two phase material submitted to a strong internal stress level.
A novel stabilization mechanism for the type VI secretion system sheath
Authors: Bernal Patricia , Furniss R. Christopher D. , Fecht Selina , Leung Rhoda C. Y. , Spiga Livia , Mavridou Despoina A. I. , Filloux Alain
Published: February 2021

Significance

The T6SS is a microscopic harpoon that bacteria use to deliver toxins into neighboring cells. While its complex assembly process has been extensively studied, it remains unclear how the two forms (long and short) of the pivotal TssA protein affect T6SS function. TssA promotes baseplate formation, orchestrates sheath extension and, in its long form, interacts with a partner protein to anchor the extending sheath at the opposing side of the cell for up to 10 min. Here we demonstrate that short TssA proteins assist sheath stabilization by associating with a yet undescribed class of T6SS proteins that accumulate at the baseplate. These T6SSs fire in seconds; therefore, this discovery provides insight into the mechanism underpinning the different fighting strategies observed across T6SS-carrying bacteria.
Anthropogenic climate change is worsening North American pollen seasons
Authors: Anderegg William R. L. , Abatzoglou John T. , Anderegg Leander D. L. , Bielory Leonard , Kinney Patrick L. , Ziska Lewis
Published: February 2021

Significance

Human-caused climate change could impact respiratory health, including asthma and allergies, through temperature-driven increases in airborne pollen, but the long-term continental pollen trends and role of climate change in pollen patterns are not well-understood. We measure pollen trends across North America from 1990 to 2018 and find increases in pollen concentrations and longer pollen seasons. We use an ensemble of climate models to test the role of climate change and find that it is the dominant driver of changes in pollen season length and a significant contributor to increasing pollen concentrations. Our results indicate that human-caused climate change has already worsened North American pollen seasons, and climate-driven pollen trends are likely to further exacerbate respiratory health impacts in coming decades.
Staphylococcal protein A inhibits complement activation by interfering with IgG hexamer formation
Authors: Cruz Ana Rita , Boer Maurits A. den , Strasser Jürgen , Zwarthoff Seline A. , Beurskens Frank J. , de Haas Carla J. C. , Aerts Piet C. , Wang Guanbo , de Jong Rob N. , Bagnoli Fabio , van Strijp Jos A. G. , van Kessel Kok P. M. , Schuurman Janine , Preiner Johannes , Heck Albert J. R. , Rooijakkers Suzan H. M.
Published: February 2021

Significance

Antibodies are crucial for the immune response against bacteria. To drive bacterial killing, antibodies should bind to the bacterial cell and induce the complement reaction. This requires target-bound IgGs to form hexameric IgG platforms that are kept together by noncovalent Fc-Fc interactions. Interestingly, pathogenic bacteria produce IgG-binding molecules that bind specifically to the Fc region needed for hexamerization. Here we demonstrate that staphylococcal protein A (SpA) fromStaphylococcus aureusspecifically blocks formation of IgG hexamers and downstream activation of complement. Furthermore, we show that IgG3 antibodies (which are not recognized by SpA) have superior capacity to activate complement and induce killing ofS. aureusby human phagocytes. These insights provide a crucial rationale for optimizing antibody therapies againstS. aureus.
Decoding ultrafast polarization responses in lead halide perovskites by the two-dimensional optical Kerr effect
Authors: Maehrlein Sebastian F. , Joshi Prakriti P. , Huber Lucas , Wang Feifan , Cherasse Marie , Liu Yufeng , Juraschek Dominik M. , Mosconi Edoardo , Meggiolaro Daniele , De Angelis Filippo , Zhu X.-Y.
Published: February 2021

Significance

Optoelectronic devices, such as photovoltaics or light-emitting diodes, are based on the interaction of light with charges in the active material. Lead halide perovskites (LHPs) have emerged as excellent materials for optoelectronics, but mysteries remain as to how these materials interact with light. Here, we develop a spectroscopic method to observe the nearly instantaneous responses of LHPs to propagating light fields. This method has allowed us to precisely trace a nonlinear material response resulting from the mixing of different light components overtaking each other during propagation. The resulting oscillatory signals could be easily confused with collective motions of ions or molecules, but are quantitatively accounted by strong nonlinear mixing and polarization-dressed light propagation in single-crystal LHPs.
Large-scale commodity agriculture exacerbates the climatic impacts of Amazonian deforestation
Authors: Maeda Eduardo Eiji , Abera Temesgen Alemayehu , Siljander Mika , Aragão Luiz E. O. C. , Moura Yhasmin Mendes de , Heiskanen Janne
Published: February 2021

Significance

The southern Amazon is one of the fastest changing places on Earth. Deforestation is giving place to a dynamic and diverse landscape, comprising small-scale farmers and large-scale commercial agriculture with differing land uses. Understanding how these different land uses affect ecosystems and local climates is essential for promoting strategies to mitigate environmental changes. Here, we show that large-scale commercial agriculture leads to a higher increase in surface temperature, in comparison with small-scale farms. We also found evidence that changes in land surface attributes over large commercial farms lead to a more prominent reduction in rainfall volumes. Our results provide compelling arguments indicating that changes in farming practices are needed to guaranty a sustainable future in the Amazon region.
Hybrid plasmonic modes in a quantum cylindrical system in the presence of a nanoscale gap region
Authors: Mahmodi Moghadam M , Mobarakabadi Sh
Published: February 2021

Theoretical analysis of hybrid plasmon polariton (HPP) wave in a cylindrical conductor–gap–dielectric structure is presented using the quantum hydrodynamic model. Numerical results show the quantum effects, including the Fermi pressure and the Bohm potential have little effect on the dispersion relations of the HPP wave in the cylindrical plasmonic system. We find that the propagation of the HPP wave in the cylindrical CGD structure is very sensitive to the radius of the metal cylinder, the thickness of the gap layer, and the permittivity of the dielectric mediums. These results will be useful for understanding the properties of the hybrid surface waves in cylindrical nanostructures.
Dynamics of a D’Alembert wave and a soliton molecule for an extended BLMP equation
Authors: Ren Bo
Published: February 2021

The D’Alembert solution of the wave motion equation is an important basic formula in linear partial differential theory. The study of the D’Alembert wave is worthy of deep consideration in nonlinear partial differential systems. In this paper, we construct a (2+1)-dimensional extended Boiti–Leon–Manna–Pempinelli (eBLMP) equation which fails to pass the Painlevé property. The D’Alembert-type wave of the eBLMP equation is still obtained by introducing one arbitrary function of the traveling-wave variable. The multi-solitary wave which should satisfy the velocity resonance condition is obtained by solving the Hirota bilinear form of the eBLMP equation. The dynamics of the three-soliton molecule, the three-kink soliton molecule, the soliton molecule bound by an asymmetry soliton and a one-soliton, and the interaction between the half periodic wave and a kink soliton molecule from the eBLMP equation are investigated by selecting appropriate parameters.
Majorana–Kondo interplay in a Majorana wire-quantum dot system with ferromagnetic contacts*
Authors: Yang Fu-Bin
Published: February 2021

We consider a single-level quantum dot (QD) and a topological superconducting wire hosting Majorana bound states at its ends. By the equation of motion method, we give the analytical Green's function of the QD in the noninteracting and the infinite interacting case. We study the effects of QD energy level and the spin polarization on the density of states (DOS) and linear conductance of the system. In the noninteracting case, the DOS resonance shifts with the change of energy level and it shows bimodal structure at large spin polarization strength. In the infinite interacting case, the up-spin linear conductance first increases and then decreases with the increase of spin polarization strength, but the down-spin is stable. However, the DOS shows a splitting phenomenon in the large energy level with the increase of spin polarization strength. This provides an interesting way to explore the physical properties of such spin dependent effect in the hybrid Majorana QD systems.
First-principles study on superconductive properties of compressive strain-engineered cryogenic superconducting heavy metal lead (Pb)
Authors: Chen Qing-Yuan
Published: February 2021

As one of the main materials in the practical application of superconductor, lead (Pb) has been used to manufacture superconducting AC power cable and some weak current fields. With the development of manufacturing technology, more and more researchers focus on exploring the physical and chemical properties of cryogenic superconducting materials, instead of blindly pursuing the improvement of the superconducting transition temperature (T

c
). In this paper, the structural properties and superconducting transition temperature under high pressure of Pb have been studied by first-principles calculations. It has shown that Pb can withstand the compressive strain up to 10% while the lattice structure remains stable, indicated by the calculations of phonon band structures. From 0% to 10% compressive strain, there is neither a band-gap nor changing of the band structure. The changing of electronic DOS at the Fermi level leads to a decreasing of T

c
. Our calculations show that Pb is a stable elemental metallic superconductor even under high pressure, which explains the reason why it has been used in practical productions.
3D patient-specific spinal cord computational model for SCS management: potential clinical applications
Authors: Solanes Carmen , Durá Jose L. , Ángeles Canós M , De Andrés Jose , Martí-Bonmatí Luis , Saiz Javier
Published: February 2021

Objective. Although spinal cord stimulation (SCS) is an established therapy for treating neuropathic chronic pain, in tonic stimulation, postural changes, electrode migration or badly-positioned electrodes can produce annoying stimulation (intercostal neuralgia) in about 35% of the patients. SCS models are used to study the effect of electrical stimulation to better manage the stimulation parameters and electrode position. The goal of this work was to develop a realistic 3D patient-specific spinal cord model from a real patient and develop a future clinical application that would help physicians to optimize paresthesia coverage in SCS therapy. Approach. We developed two 3D patient-specific models from a high-resolution MRI of two patients undergoing SCS treatment. The model consisted of a finite element model of the spinal cord and a sensory myelinated nerve fiber model. The same simulations were performed with a generalized spinal cord model and we compared the results with the clinical data to evaluate the advantages of a patient-specific model. To identify the geometrical parameters that most influence the stimulation predictions, a sensitivity analysis was conducted. We used the patient-specific model to perform a clinical application involving the pre-implantation selection of electrode polarity and study the effect of electrode offset. Main results. The patient-specific model correlated better with clinical data than the generalized model. Electrode-dura mater distance, dorsal cerebrospinal fluid (CSF) thickness, and CSF diameter are the geometrical parameters that caused significant changes in the stimulation predictions. Electrode polarity could be planned and optimized to stimulate the patient’s painful dermatomes. The addition of offset in parallel electrodes would not have been beneficial for one of the patients of this study because they reduce neural activation displacement. Significance. This is the first study to relate the activation area model prediction in dorsal columns with the clinical effect on paresthesia coverage. The outcomes show that 3D patient-specific models would help physicians to choose the best stimulation parameters to optimize neural activation and SCS therapy in tonic stimulation.
Section 1.01 Methodology for assessing local overloads of elements of fixed offshore platforms with corrosion defects based on data on temperature contrasts: results of physical modeling
Authors: Starokon I V
Published: February 2021

Today, offshore oil and gas fields are being developed in the world using stationary offshore platforms. Offshore platforms are corrosive during operation. As a result of this effect, cavities or crack-like defects are formed in the platform elements, which are stress concentrators and can cause a critical overload of the platform elements. In order to prevent such a situation, it is necessary to identify dangerous corrosion defects in a timely manner. The author set up a physical experiment, which consisted in the creation of artificial corrosion defects of the V-shaped form, followed by the action of intense heat flows on them. On the basis of the formulas obtained by the author, a practical solution to the problem is given, which makes it possible to determine the size of corrosion damage and, from temperature contrasts, to calculate local overloads in the elements of the offshore platform.
Development and design of a mobile power plant in the form of a standalone power supply
Authors: Abramovich B N , Ustinov D A , Abdallah W J
Published: February 2021

The work is devoted to increasing the energy efficiency of uninterruptible power supplies in enterprises with a continuous technological cycle. During the operation of continuous technological processes, a power failure even for a short period of time leads to significant economic damage. The most modern technical solution to this problem is the creation of guaranteed power supply systems using diesel power plants (DES) and uninterruptible power supplies (UPS), based on rechargeable batteries and supercapacitor modules. It is proposed to use supercapacitors in parallel with the battery in order to ensure the stable operation of the diesel generators under starting conditions, as well as during load transfer. In this case, when using supercapacitors, it becomes possible to reduce the power capacity of the generators and uninterruptible power supplies along with the size of their batteries. Therefore, the cost of the solution decreases and its energy efficiency increases. To test the efficiency of the system, a computer model was created using MATLAB. The system showed a successful operation in supplying the load from all the power sources as well as maintaining Unity Power Factor at the Mains/Generator side.
Vacuum contactor operation with parallel connection of independent consumers
Authors: Belsky R A
Published: February 2021

This work presents a model of a transformer substation with parallel connection of independent consumers via vacuum switches. Several options of an electric arc model are considered upon switching off a vacuum switch such as: KEMA model and “black box” model. Modern computer models of vacuum switches were analyzed. Since the model data were not suitable for the conditions of the experiment, a simulation computer model was developed that reflects the specifics of the operation of the substation and of the transition process upon disconnection of one or several vacuum switches. The results of the developed methodology of analyzing transition processes were verified. To check the results of computer simulation, an experimental model was constructed, it consisted of: an electric load (inductive nature), a power supply, two vacuum switches, and a measuring circuit. The circuit is switched on and off using a pneumatic system controlled by a microcontroller. The primary purpose of the work is to check mutual influence of vacuum switches upon parallel disconnection, since there may be a restrike caused by effects of switching overvoltage between neighboring switches upon irregular disconnection. The effects of a transition process in one switch on the total current of the entire system were identified. A stand for a projected trial was demonstrated as well.
Modeling the process of redistributing power consumption using energy storage system with various configurations to align the electrical loads schedule
Authors: Bardanov A I , Vasilkov O S , Pudkova T V
Published: February 2021

The paper considers issues related to the analysis and adjustment of electrical load schedules. The main characteristics of the load graphs are represented in this paper. The research deals with issues of possibility of aligning load graphs by using energy storage devices. The configuration of the storage system has been identified, which allows expanding its functionality. A logical-numerical model of a hybrid energy storage system has been developed. As a result of the simulation, dependencies are obtained that confirm the efficiency of using power storage devices to align the load schedules.
Power stabilization system for the regulated electric drive of transport vehicles
Authors: Bolshunova O M , Korzhev A A , Vatlina A M
Published: February 2021

One of the important parameters of using the hydraulic transport system in mining enterprises is considered. A method for regulating the ground pump drive and a computer model of the drive power stabilization system are proposed. The simulation was performed in the Scilab program. The performance of the proposed model was checked. The results of simulation with different values of the current and torque are shown. The efficiency of the proposed method for regulating the ground pump drive is evaluated.
Modelling of induction motor incorporating magnetic saturation
Authors: Ustinov D A , Garipov B I
Published: February 2021

The paper studies the need to take into account the magnetic saturation of a squirrel-cage induction motor (IM). A mathematical description of an IM with linear and nonlinear magnetic characteristics is given. The simulation of motor’s direct start, as well as the field oriented control (FOC) system in Simulink Matlab environment is presented. The results of simulation are presented: time diagrams and mechanical characteristics of the motor. The conclusion is made whether it is necessary to take into account saturation in the study of transients in an asynchronous squirrel-cage motor.
Simulation of the process of isothermal backward extrusion of a thick-walled hollow billet
Authors: Pasynkov A A , Larin S N
Published: February 2021

The processes of extrusion of bar billets are the most widely used for producing metal products in the form of a tall cylinder with thin or thick walls. The process is characterized by high hydrostatic pressure, which makes it possible to achieve high degrees of deformation. However, it is worth noting that in this case great forces and loads on the tool take place. Implementation of the processes of extrusion of billets from difficult-to-form alloys can significantly reduce the deformation forces and ensure the formation of an advantageous strain-stress state. This process is rather sophisticated, subject to the theoretical justification. It is a matter of interest to provide justification of the processes of isothermal extrusion of thick-walled hollow billets, allowing one to produce cylindrically shaped products with relatively thin walls and a thick bottom with a hole. The paper discusses the process of isothermal extrusion of thick-walled hollow billets from high-strength non-ferrous alloys. The process simulation was performed using a software package based on the finite-element method. The influence of various parameters on stresses and strains, varying during deformation in the component, was determined. The conditions of loading for the process were analyzed. The results obtained can form the basis for the development of techniques for performing the backward extrusion of hollow billets in isothermal conditions.
Sizing parameters of interior permanent magnet synchronous motor based on torque-speed characteristics
Authors: Shklyarskiy Y E , Shklyarskiy A Y , Lutonin A S
Published: February 2021

This paper presents a sizing algorithm for an interior permanent magnet synchronous motor based on its torque-speed characteristic and how these characteristic shifts because of changing motor’s parameters. This knowledge must be helpful in designing motor control systems, where there is no need for a precise model. Also, the proposed method is useful for rapid prototyping based on the existing motor model. The methodology for calculating the torque-speed characteristics is given. The resulting calculated graphs are given. PMSM motor control parameters are designed based on the reference model and verified in MATLAB/Simulink software package. Simulation results are given.
Modelling the motion of a mobile robotic complex in the coastal zone
Authors: Makarov V S , Belyaev A M , Belyakov V V
Published: February 2021

The article discusses the modeling of the curvilinear motion of a mobile robotic complex (MRC) with a caterpillar-modular mover on sandy deformable soil. Dependencies describing the main characteristics of the support base (modulus of elasticity, angle of internal friction, specific cohesion of soil, soil density) are given. The simulation was conducted in the Adams Tracked Vehicle environment. Shown are 3D views of the developed model of MRC. Typical sections of MRC curvilinear motion simulation on a sandy support base are considered. Graphs of changes in resistance to movement MRC are given for curved and straight sections. The calculations of the total resistance in a rectilinear motion and during rotation showed that the average values of the resistance to movement in a rectilinear motion are 1.6 kN with a curvilinear of 1.94 kN. The experimental values of the resistance force in a rectilinear motion were 1.45-1.7 kN. Thus, the maximum deviation between theoretical and experimental data was no more than 10%.
The influence of power system parameters on breaks of fault currents in the generator circuit breaker
Authors: Safonov E , Frolov V
Published: February 2021

The purpose of this paper is to study the factors that influence on the delayed current zeros phenomena in the generator network. For this purpose the equivalent circuit of the generator network was developed. The fault transients simulations have been performed by means of the Matlab/Simulink software package. Consequently, the dependence characteristics of the delayed current zeros phenomenon on the external power system parameters (inductance, length of power lines, reactive power balance) were obtained. The amount of reactive power generated by power lines depends on its length. This power, in turn, is consumed by the generation network and external power system. The greater the reactance of the external power system, the greater of this reactive power the generator consumes, which, in turn, increases direct-axis armature reaction and direct component of the short-circuit currents. The long arcing time by the delayed current zeros phenomena will cause damage to the transformer, circuit breaker and can negatively affect the stability of the power system. These results are also demonstrated numerically.
Accounting for the plasma background radiation influence and calibration curve export in atomic emission spectrometry with CCD-based registration system when determining metal and alloy impurities
Authors: Sukhomlinov V S , Mustafaev A S , Popova A N
Published: February 2021

This paper is dedicated to development and application of an algorithm allowing determining an accurate actual value of the plasma background radiation under the analytic element line using standard data obtained from emission spectrometer registration system. A unique technique has been developed that allows calibrating spectrometers in the range of small concentration of impurities with two standard samples, which is very relevant for analysis of metals and alloys, powdered samples, ultrapure materials. The paper demonstrates efficiency of this technique when applied to series-produced emission spectrometers manufactured in Russia.
Modelling and operation analysis of autonomous electromechanical power supplies with a commensurate power load
Authors: Ustinov D A , Abramovich B N , Abdallah W
Published: February 2021

Nowadays, diesel power plants (DPS) are widely used as sources of primary, backup or emergency power supply for various facilities. Mathematical modeling and optimization techniques are widely used for studies in order to improve energy and economic efficiency of diesel power plants. The article describes the modeling of a stand-alone electromechanical power system consisting of a Diesel Power Plant and an ESS (Energy Storage System) based on supercapacitors with a load of comparable power of a diesel motor to increase its energy efficiency.
Automating production engineering for custom and small-batch production on the basis of simulation modeling
Authors: Khrustaleva I N , Lyubomudrov S A , Chernykh L G , Stepanov S N , Larionova T A
Published: February 2021

The paper describes a simulation model of production engineering for custom and small-batch production. The described simulation model includes three levels: control over the operation of separate elements of the production system and their interaction, planning and modeling of various variants of a processing route, selection of rational cutting parameters, and constraints analysis of the production system. In order to determine the rational cutting modes, total accuracy of processing is calculated and Taguchi method is applied. A rational variant of the production process is selected by multiple criteria analysis.
Analysis of the voltage drop of a drilling rig connected to a local energy network
Authors: Chervonchenko S S , Frolov V Ya
Published: February 2021

The article discusses and analyzes the operation of an autonomous electrical complex of a drilling rig in an emergency mode, namely when the supply voltage drops. The concept of voltage drop is also described, a comparative characteristic of technical devices and methods of overcoming voltage drops, indicating the disadvantages and advantages, is given. Modeling of an autonomous electrical complex of a drilling rig is performed in the MATLAB Simulink software package with a description of the parameters of the main elements. The voltage drop is achieved by a sharp increase in the load power consumption, which in reality is achieved by the drilling rig head getting stuck in the hard layers of the earth’s surface. As a result, there are graphs of changes in the voltage value at the terminals of the electric motor of the drilling rig, depending on the magnitude of the load. Based on these graphs, we can conclude that with an increase in load, the autonomous system does not have its own reserves and power reserves (and according to regulatory documents, this margin is 20%) in order to overcome the voltage drop and return it to acceptable values for further uninterrupted operation. As a conclusion, we can say that today the only optimal option in terms of material costs and technical features is to connect a backup diesel generator connected in parallel to the main one and having a comparative power.
Nondestructive quality testing of concrete and asphalt concrete pavements
Authors: Potapov A I , Shikhov A I , Dunaeva E N
Published: February 2021

The technical level of the applied methods and controls has an impact on the result of construction and installation works. One of the main tasks of contractors in the process of paving is to quickly determine the parameters of asphalt pavement. The quality of the asphalt pavement device allows you to increase the service life and reduce the cost of repairing road surfaces. A number of methods and means of nondestructive quality testing of concrete and asphalt concrete pavements are considered. Some characteristics of defects of concrete and asphalt concrete pavements are given. The main attention is paid to ground-penetrating radar methods, eddy-current, radiation and acoustic, also the devices implementing these methods are considered.
Complex simulation model of functioning mine telecommunication system using Power Line Communication technology
Authors: Shpenst V A
Published: February 2021

This paper considers a modern development of telecommunication systems as a part of electrical complexes of underground facilities, namely, application of PLC technologies for complexing electrical systems. A description is provided of the main tool of experimental studies of such systems, a simulation model of operation, its structure, development sequence and main elements, as well as an experimental validation of the model.

The proposed model will allow solving a wide range of problems in the process of studying telecommunications systems and power supply systems for underground structures. Model development included the formulation of complex research tasks, the creation of the conceptual model, the formation of a set of requirements for the modeling algorithm, the development of a mathematical model, creating a simulation program in C++ with the use of JBuilder, the company Embarcadero version 10.3, as well as the verification of the simulation model. Based on the considered structure of the PLC network, it is proposed to include an information generation module, a connection module, a transmission line module, a modulation, encoding and decoding module, an information processing and noise reduction module, a subscriber module and a performance evaluation module in the model of integration of power supply and telecommunications systems for underground structures. To solve the problem verify the model was developed methods of research the effectiveness of various algorithms for transmission power supply networks underground structures, allowing an informed choice of data transfer methods and rational selection of the non-necessity to implement the methods selected equipment and conducted a series of experimental studies on real industrial underground facilities.