bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of Personnel Actions in the Most Dangerous Accidents
Authors: Berberova Maria
Published: November 2020

The reliability of the human operator is an essential indicator of the safe operation of nuclear power plants. Mistakes can be made during performance checks, maintenance, at the stage of accident management, etc. A number of different factors affect the stability of a nuclear power plant: level of organization of the project, quality of equipment in operation, selection and training of competent personnel, maintaining the qualifications of NPP workers, and etc. In the “man-machine” system, the reliability of the technical component is calculated by known methods and in accordance with established reliability standards. However, the “human” component cannot be technically and accurately determined, therefore, it is necessary to undertake systematic efforts to increase and subsequently maintain the achieved level of reliability of this component. The contribution of the human factor to emergencies at technosphere facilities is significant: 70% of air crashes, 50% of disasters in the fleet occur precisely due to incorrect actions (low reliability) of personnel. According to statistics, the main causes of accidents are improper actions (low reliability) of personnel (60-70%), technical reasons (20-30%), adverse effects of external factors, etc.
An effective method for calculating the elements of thermal power plants, which are reduced to solving systems of partial differential equations
Authors: Kler Alexander , Apanovich Danil , Maximov Alexey
Published: November 2020

Calculations of dynamic processes in the elements of thermal power plants (TPP) (heat exchangers, combustion chambers, turbomachines, etc.) are necessary to justify permissible and optimal operating modes, the choice of design characteristics elements, assessing their reliability, etc. Such tasks are reduced to solving partial differential equations. At present time for such calculations are mainly used finite-difference method and finite element method. These methods are cumbersome and complex. The article proposes a method, the main idea of which is to reduce the solution of equations to solving linear programming problems (LP) is demonstrated by the example heat exchanger of periodic action. The mathematical description includes the following energy balance equations for gas and ceramics, respectively, on the plane, where - indicates the length of the heat exchanger, and - the operating time. Also provides a more complex model, taking into account the spread of heat inside the balls of the ceramic backfill.
Developing a New Software Tool for Research of Interstate Power Grids Expansion
Authors: Trofimov Ivan L. , Trofimov Leonid N.
Published: November 2020

The aim of our research is to develop a new software tool – the Computing and Geo-information System for study of prospective interstate power grids expansion. The new software tool developed by the authors consists of several functional parts (software modules): graphic module for visual analysis of processed data, geo-information and cartographic module, module for working with the integrated ORIRES model (model for optimization of power systems expansion and their operating modes). In this paper, we consider features and technical description of the new software tool. The obtained results of the integrated ORIRES model in tabular, graphic and cartographic forms are presented.
Multi-criteria placement and capacity selection of solar power plants in the “Baikal-Khövsgöl” Cross-Border Recreation Area
Authors: Ivanova Irina , Shakirov Vladislav
Published: November 2020

The problem of power supply to remote consumers in the “Baikal-Khövsgöl” Cross-Border Recreation Area, associated with the high length and low reliability of power lines is discussed. The assessment of the modes of the power distribution grid showed that the introduction of new consumers in this territory will lead to unacceptable voltage deviations, even taking into account the installation of reactive power compensating devices. Since the area under consideration has a high solar energy potential, it is advisable to use distributed solar generation. The choice of locations and capacities of solar power plants is a multi-criteria optimization problem. Four criteria are proposed: total voltage deviation, total active power losses, reliability and capital costs for construction. An algorithm for multi-criteria optimizationis developed and implemented as a program in the MATLAB, which consists in sequential verification of the feasibility of installing additional power of solar power plants at the consumers of each of the substations under consideration. For each variant, the electric grid mode is assessed using the Power system analysis toolbox program. Solutions for the choice of locations and capacities of solar power plants are obtained, providing high scores by criteria in accordance with the given criteria importance coefficients.
Areas of using environmentally friendly fuel combustion technologies at TPPs of the Irkutsk Region
Authors: Lachkov Georgiy
Published: November 2020

The use of coal as the main fuel at thermal power plants in the Irkutsk Region, the significant moral and physical depreciation at many of them of the main generating equipment, mainly boiler plants, due to the long service life, determine the relevance of environmental considerations in organizing rational energy supply to regional consumers in the future. The study of the age composition, technical and environmental characteristics of the boiler equipment of thermal power plants in the region. A review of advanced technologies for burning fuel in large installations with the aim of producing thermal and electric energy. Based on an analysis of the state and environmental characteristics of thermal power plants in the Irkutsk Region, a review of advanced technologies for burning fuel in large thermal power plants, the main directions of the future use of these technologies at thermal power plants in the region are considered, taking into account their features and environmental characteristics in order to reduce harmful emissions. The list of thermal power plants recommended for conversion to natural gas burning is determined, as well as the list of thermal power plants where it is advisable to use boilers with a ring furnace or boilers with a low-temperature vortex furnace. The potential volume of reduction of harmful emissions from the introduction of advanced technologies for fuel combustion at thermal power plants of the region is estimated.
Increased Environmental Requirements for Energy Objects in the Central Ecological Area of the Baikal Natural Territory: Problems and Condition for Implementation
Authors: Maysyuk Elena P.
Published: November 2020

The most important document regulating the use of natural resources in the territories adjacent to the lake Baikal in Russia became the federal law No. 94 “On the protection of the lake. Baikal” from 1 May 1999. A list of prohibited activities has been approved for the central ecological area which now again discuss. Taking into account the categorization of objects that have a negative impact on the environment, the energy objects of the central ecological area are assigned to categories II and III. And in case of changes concerning of categorization in the list of prohibited activities, it means that operation of energy objects will prohibited. The main environmental problem of the energy sector is the use of coal and the presence of a hazard class 1 substance in the emissions. To achievement environmental requirements, it is necessary to replace coal with alternative environmentally friendly types of energy carriers (natural gas and electricity). In order to implement the increased requirements for energy objects, it is necessary to develop a special package of normative legal acts and government support measures, including significant financial costs, focused on this territory.
Modeling of Long-term Operating Regimes of Hydro Power Plants as Part of Energy and Water Systems in the Context of Uncertainty
Authors: Nikitin Viacheslav , Abasov Nikolay , Osipchuk Evgeny
Published: November 2020

Energy and water management systems are closely interrelated through the operating regimes of Hydro Power Plants (HPP) or HPP cascades. This is first of all, characteristic of energy systems with a large share of HPP. One of such systems is the energy system of Siberia, which includes the Angara-Yenisei cascade of HPP, the largest in Russia and one of the largest in the world. The studies were carried out on the example of this energy system and the water management system of the Angara and Yenisei basins. A specific feature of the energy and water management systems of Siberia is a significant impact of stochastic factors on their operation. These factors include natural (water inflow in the reservoirs in the spring-summer period and outdoor temperature in the autumn-winter period), and also economic (demand for electric and thermal energy, electricity and heat prices) factors. The paper presents mathematical models for the joint study of energy and water systems. These models factor in the specifics of the systems during planning for a period of up to 1 year. Modeling of the interconnected operation of energy and water systems makes it possible to solve important problems. These are the improvement in the reliability and stability of the considered systems, increase in their economic efficiency (minimization of electricity prices for consumers), assessment and minimization of various risks, prevention from or reduction in possible damages, rational planning of repairs, the formation of fuel reserves at thermal power plants, and others.
Hydrogen Energy: a New Dimension for the Energy Cooperation in the Northeast Asian Region
Authors: Popov Sergei , Maksakova Darya , Baldynov Oleg , Korneev Konstantin
Published: November 2020

The Northeast Asian Region is a home for the major world’s energy importers and Russia – the top energy exporter. Due to the depletion of national fossil energy resources, the industrialised East Asian economies are facing serious energy security issues. The snapshot of the intraregional energy trade in 2019 was analysed in terms of development potential. Japan, Korea and China are at the frontline of hydrogen energy technologies commercialisation and hydrogen energy infrastructure development. The drivers for such endeavours are listed and national institutions for hydrogen energy development are characterised. The priorities related to regional cooperation on hydrogen energy in Northeast Asia were derived on the basis of hydrogen production cost estimations. These priorities include steady development of international natural gas and power infrastructure. The shared process will lead to the synergy of regional fossil and renewable resources within combined power and hydrogen infrastructure.
Energy cooperation between Russia and Mongolia: priority areas and mechanisms to pursue them
Authors: Saneev Boris , Korneev Anatoly , Batmunkh Sereeter , Bathuyag Sodovin
Published: November 2020

The study examines the directions of Russian-Mongolian energy co-operation. The focus is on an analysis of internal and external factors that negatively affect the implementation of the current inter-country energy projects. The mechanisms are proposed to cope with the factors limiting energy cooperation.
Analysis power shortage minimization methods in the modern processing software for adequacy assessment of electric power systems
Authors: Iakubovskii Dmitrii , Krupenev Dmitry
Published: November 2020

Analysis of domestic and foreign software systems for assessing the resource adequacy showed a variety of models and methods used in them. Many software systems use both linear and nonlinear models, these models are optimized according to various criteria to simulate the operation of the system. As tools for solving, software usually use commercial high-level modelling systems for mathematical optimization. However, in addition to the existing ready-made commercial solutions, the authors consider the effectiveness of optimization methods, as well as their parallelized versions, which can be independently implemented and applied as a solver for a specific problem. As a result, it was confirmed that these methods can be used to solve the problem, but they are less effective relative to a commercial solver. From the point of view of accuracy and resources spent on calculations, the most effective of the independently implemented methods turned out to be the parallelized method of differential evolution, which was confirmed by numerical experiments on small systems.
Multy-year oscillations investigation of winter temperatures Prediction of integrated temperature difference during the heating period
Authors: Khazheev Ivan
Published: November 2020

To estimate possible deviations in fuel consumption for heating based on meteorological observations of previous years, the integrated temperature difference inside and outside the building during the heating season is used. When the heating period is divided into two subperiods relative to the considered date (for example, before and after December 1), the accumulated and residual integral temperature differences are obtained. The assumption about the presence of a statistical relationship between the accumulated and residual integral temperature difference is confirmed. A model for predicting the probability of the expected values of the integral temperature difference for the upcoming heating period is developed. The model is focused on obtaining matrices of conditional probabilities of observations from intervals of dividing the accumulated integral temperature differences into intervals of residual integral temperature differences.
Matrix of Vulnerability of Decentralized Areas to Local Energy Security Risks in the Northern and Arctic Zones in the Structural Set of Solutions
Authors: Kiushkina Violetta , Lukutin Boris
Published: November 2020

The tension of the state of decentralized power supply systems in the northern regions, including the Arctic zones, has always been determined by the specific features of their geographical location and the functioning of the economy, which in themselves generate a number of local energy security risks. Nevertheless, both modern and retrospective analysis of energy zones in isolated hard-to-reach territories retains an assessment of the crisis of the situation without the dynamic type of its improvement in ensuring energy security. The aggregate analysis of the formed risk matrix with the heterogeneous nature of their sources, the categorization of the depth of consequences and the probability of implementation, made it possible to obtain a map of local risks of energy security in decentralized regions. On the basis of this, an approach and structure of a set of recommendations for improving energy security is presented in the model of combining the rank of the indicator’s importance, the priority of risks and the expected social, environmental and economic effects in a reasonable option for choosing solutions and recommended measures to ensure a stable state and development of decentralized zones of power supply and energy facilities of territories Northern regions and Arctic zones.
Effect of the projection time frame on the techniques for assessment of energy security performance
Authors: Kononov Yuri
Published: November 2020

The paper studies the problem of overall assessment of energy sector development options from the standpoint of meeting energy security requirements. It is shown that as the projection time frame extends further into the future, its economic component gains in importance on a par with integral indicators descriptive of strategic threats to and sustainability of energy systems development. Methodological approaches to assessment of these indicators are proposed.
Calculation of Nodal Prices for Heat Energy in Heat Supply Systems
Authors: Penkovskii Andrey , Khamisov Oleg , Kravets Angelica
Published: November 2020

The article is devoted to the calculation of nodal prices for heat energy in heat supply systems. The problem, mathematical model and method of calculating nodal prices of heat energy for all consumers of the heat supply system considered, taking into account the different cost of heat production by sources, optimal flow distribution, and placement of consumers in the heat network (distance from the source). As the main computational tool for calculating nodal prices for heat energy, the Lagrange multiplier method used in the problem of modes optimizing in heat supply system, which allows explaining in detail the formation of the price for heat energy in each node. With the help of the proposed methodological support, practical research has been carried out for real heat supply system.
A method of power system simulation model reduction for transmission grid frequency response analysis
Authors: Solodovnikov Valery , Tulsky Vladimir , Shamonov Roman
Published: November 2020

Application of the frequency scan method for the determination of resonant conditions in a transmission power grid requires great effort since the harmonic power system simulation model needs to be developed. This process is rather complicated since the original model used for fundamental frequency load-flow analysis is built with respect to certain assumptions and, thus, intolerable errors are introduced when frequency-domain properties of the power system are investigated. To strike a balance between inputs needed for the development of such model (time, data amounts) and accuracy of the results, it is proposed to employ a method which makes it possible to represent dead-end, double-ended and tapped 110-220 kV substations as a single frequency-dependent equivalent so that the harmonic power system model is reduced. Such an element essentially is a series R-L or R-L-C shunt, parameters of which vary with frequency. The algorithm for the evaluation of its parameters is proposed and the test case for a real 110 kV grid area is discussed. Results of the method application show that it can be used in practice.
Application of ETAPTM eTraXTM software package for digital simulation of distribution network that feeds an AC traction power supply system
Authors: Tulsky Vladimir , Shevlyugin Maxim , Korolev Aleksei , Subhanverdiev Kamil , Murzintsev Alexander , Zhgun Ksenia , Silaev Maksim , Khripushkin Nikita , Baembitov Rashid
Published: November 2020

Voltage unbalance in power systems feeding AC traction power systems is a worldwide known problem. One of the main aspects of this problem is the negative effect of voltage unbalance on motor loads causing operating problems and economic damage. It is necessary to perform unbalanced power flow studies and calculate voltage unbalance indexes to assess this negative effect of voltage unbalance and the develop of compensating measures during the design stage. Usually, calculations of the AC traction power supply system and the distribution network feeding it are carried out separately during the design of new lines of railways electrified by alternating current (AC) and reconstructing of existing ones. This approach is a source of deviations in the power flow studies because the lack of consideration of mutual influences between the traction power system and the distribution power system. In this paper, we compare a digital model in which the traction power supply system and the distribution network are modeled separately with a model that considers mutual influences between the traction and external power supply systems, including power flows through the traction network caused by the distribution network (transit currents). For digital modeling of these processes, authors used ETAPTM software with eTraXTM package. It allows to run unbalanced power flow studies when the generation and load are being changed over time, including train movement. During a separate simulation of the traction power system and distribution network, traction network was modelled using the equivalent sources connected to traction substation buses and the distribution network was modeled taking into account the fact that traction load was given from the simulation of the traction power system. The traction load was considered as lumped loads connected to the traction substation buses.At the same time, in both cases, the unbalanced power flow study was carried out by the phase domain method. Based on the results of two models comparison, it was concluded that the combined model containing a traction power supply system and distribution network, is more effective in terms of improving the accuracy of assessment voltage unbalance in accordance with current regulatory and technical documents on power quality.
Selection of a Complex of Parameters of Distribution Electric Networks with Respect to Technical Limitations
Authors: Taslimov A D
Published: November 2020

The article contains an optimization analysis of the regularities of the formation of the parameters of urban distribution networks of 10 kV, taking into account the technical limitations by the method of criteria analysis, which revealed the feasibility of using a limited number of used cable cross-sections, depending on the density of the electrical load and on the schemes of urban distribution networks.
Evaluation of the Effectiveness of Electromagnetic Treatment of Well Water
Authors: Berdishev A.S. , Djumaboyeva Z.Z.
Published: November 2020

The article presents the results of investigation on wastewater purification from various contaminants and bacteriological infections by the method of physical-chemical treatment. The paper substantiates the choice of effective methods of ozonation by physical fields, in particular by electromagnetic ones. The results are substantiated experimentally and make it possible to continue research in the chosen line.
On technology for modeling and forecasting the interrelated development of regional fuel and energy complexes of Russia and Mongolia
Authors: Kazakov Alexander , Lempert Anna , Stolbov Alexander
Published: November 2020

The paper considers the main ideas of proposed computational technology for scenario modeling and forecasting the development of the national fuel and energy complexes of Russia and Mongolia, regarding to the intercountry trade in fuel and energy resources. The proposing technology exploits the ideas of multi-agent systems (MASs) and agent-based simulation models (ABSMs) as they can act as unifying means for different types of decision-making methods by distributed objects. Methodological principles and architecture for ABSM of the national fuel and energy complexes of Russia and Mongolia were proposed. The implementation issues of the model in the Adskit software tool is discussed. The problem of laying routes of extended energy objects is also considered. Based on the principles of geometric optics the author’s solution algorithm in the form of a special case of the variational problem was proposed to deal with this problem. The application of MAS and ABSM paradigms for forecasting and evaluating the state of the fuel and energy sector in Russia and Mongolia allows one to organize a step-by-step research of the energy system with the gradual development of the model: increasing the types of objects and agents; improving decision-making algorithms, including those based on mathematical models; creating complex scenarios. The technology forms methodological basis for supporting decision-making process of evaluation the prospective variants of bilateral energy cooperation of Russia and Mongolia and related project effectiveness.
Psychotherapie mit älteren Männern
Authors: Peters Meinolf
Published: November 2020

Der Anteil älterer Männer ist in der Psychotherapie gering. Sind ältere Männer in der Psychotherapie Fremde, die sich unwohl fühlen, und sie deswegen meiden? „Fremdeln“ auch Psychotherapeuten mit älteren Männern als Klienten? Wie könnte sich daran etwas verändern? Dies soll im Folgenden genauer betrachtet werden.
Leid kennt kein Geschlecht
Authors: Dinger-Broda Andrea , Broda Michael
Published: November 2020

Andrea Dinger-Broda und Michael Broda haben vor über 20 Jahren eine verhaltenstherapeutische Praxisgemeinschaft gegründet – in einer ländlichen Region mit hoher Arbeitslosigkeit. Zwei Psychotherapeutinnen und ein Psychotherapeut mit Kassensitz, eine angestellte Psychotherapeutin sowie vier Psychotherapeutinnen in Ausbildung versorgen ca. 280 PatientInnen in laufenden Therapien. Die Wartezeit auf ein Erstgespräch beträgt aktuell vier Monate. Christoph Flückiger hat mit den PraxisgründerInnen gesprochen.
Die Feminisierung eines Berufes
Authors: Jaeggi Eva
Published: November 2020

Ausgehend von der Tatsache, dass immer weniger Männer den Beruf des Psychotherapeuten wählen, werden Überlegungen über die Ursachen und Konsequenzen dieser Tatsache angestellt. Da es wenig valide Daten dazu gibt, lassen sich lediglich Hypothesen aufstellen. Dabei werden sowohl biologische als auch soziologische und Gender-Aspekte erörtert. Diese können sowohl in Hinblick auf die Motive zur Berufswahl als auch auf die möglichen Folgen der Feminisierung des Berufs herangezogen werden.
Neutral-Eosin Y-Catalyzed Regioselective Hydroacylation of Aryl Alkenes under Visible-Light Irradiation
Authors: Tang Xinxin , Wu Jie , Liu Haiwang , Xue Fei , Wang Mu
Published: November 2020

Styrene derivatives were hydroacylated with exclusive anti-Markovnikov selectivity by using neutral eosin Y as a direct hydrogen-atom-transfer (HAT) catalyst under visible-light irradiation. Aldehydes and styrenes with various substituents were tolerated (>20 examples), giving the corresponding products in moderate to high yields. The key acyl radical intermediate was generated from a direct HAT process induced by photoexcited eosin Y. Subsequent addition to styrenes and a reverse HAT process generated the ketone products.
Diagnostic Value of Cholinesterase Activity for the Development of Postoperative Delirium after Cardiac Surgery
Authors: Saha Shekhar , Karaca Kübra , Jebran Ahmad Fawad , Waezi Narges , Ort Katharina , Brandes Ivo , Hagl Christian , Niehaus Heidi
Published: November 2020

Background Depression of cholinesterase (CHE) activity has been reported to lead to an amplified neuroinflammatory response, which clinically manifests as postoperative delirium (PD). This observational study investigates the association between CHE activity and the development of PD following elective cardiac surgery.

Methods Patients with preexisting neurologic deficits or carotid artery disease as well as patients undergoing reoperations or procedures under circulatory arrest have been excluded from this study. The Mini-Mental State Examination, the Confusion Assessment Method for the Intensive Care Unit, and the Intensive Care Delirium Screening Checklist were performed at regular intervals. CHE activity was estimated pre- and postoperatively until postoperative day (POD) 5 and at discharge.

Results A total of 107 patients were included. PD was diagnosed in 34 (31.8%) patients, who have been compared with those without PD. Time on ventilator, length of ICU, and hospital stay were longer in patients with PD (p = 0.001, p < 0.001, and p = 0.004, respectively). MMSE scores were lower in patients with PD (p < 0.001; p = 0.015). CHE activity on POD 1 to 4 as well as at discharge were lower in the delirium group (p = 0.041; p = 0.029; p = 0.015; p = 0.035; p = 0.028, respectively). A perioperative drop of CHE activity of more than 50% and a postoperative CHE activity below 4,800 U/L (on POD 0) were independently associated with an increased risk of development of PD (p = 0.038; p = 0.008, respectively).

Conclusion In addition to the established functional tests, routine estimation of CHE activity may serve as an additional diagnostic tool allowing for the timely diagnosis and treatment of PD in cardiac surgery patients.
Computed Tomography-Guided Trans-scapular Coil Localization for Pulmonary Nodules
Authors: Zhang Jian-Hua , Zhou Shi-Qing , Xia Feng-Fei , Wang Tao
Published: November 2020

Background The aim of the study is to evaluate the feasibility, safety, and effectiveness of preoperative computed tomography (CT)-guided trans-scapular coil localization (TSCL) of scapula-blocked pulmonary nodules (PNs).

Methods Between November 2015 and May 2020, 11 patients underwent preoperative CT-guided TSCL procedures owing to PN occlusion by scapula.

Results A 100% technical success rate was achieved for CT-guided TSCL, with one coil being used for each PN. One patient (9.1%) developed pneumothorax. Successful video-assisted thoracoscopic surgery (VATS)-guided wedge resection of these scapula-blocked PNs was conducted in all patients.

Conclusion CT-guided TSCL can be simply and safely used to facilitate successful VATS-guided wedge resection of scapula-blocked PNs.
The Role of the Heart Team in Patients with Diffuse Coronary Artery Disease Undergoing Coronary Artery Bypass Grafting
Authors: Dourado Luciana Oliveira Cascaes , Pereira Alexandre C. , Poppi Nilson Tavares , Cavalcante Rafael , Gaiotto Fabio , Dallan Luis Alberto Oliveira , Bittencourt Marcio Sommer , Cesar Luiz Antonio M. , Gowdak Luis Henrique W.
Published: November 2020

Background In patients eligible for coronary artery bypass grafting, no data assess the importance of the Heart Team in programming the best surgical strategy for patients with diffuse coronary artery disease (CAD). This study aims to determine the contribution of the Heart Team in predicting the feasibility of coronary artery bypass graft and angiographic surgical success in these patients based on visual angiographic analysis.

Methods Patients with diffuse and severe CAD undergoing incomplete coronary artery bypass graft surgery were prospectively included. One-year postoperative coronary angiograms were obtained to evaluate graft occlusion. Two clinical cardiologists, two cardiovascular surgeons, and one interventional cardiologist retrospectively analyzed preoperative angiograms. A subjective scale was applied at a single moment to quantify the chance of successful coronary artery bypass grafting for each coronary territory with anatomical indication for revascularization. Based on individual scores, the Heart Team's and the specialists' scores were calculated and compared.

Results The examiners evaluated 154 coronary territories, of which 85 (55.2%) were protected. The Heart Team's accuracy for predicting the angiographic success of the surgery was 74.9%, almost equal to that of the surgeons alone (73.2%). Only the interventional cardiologist predicted left anterior descending territory grafting success. The Heart Team had good specificity and reasonable sensitivity, and the surgeons had high sensitivity and low specificity in predicting angiographic success.

Conclusion The multispecialty Heart Team achieved good accuracy in predicting the angiographic coronary artery bypass graft success in patients with diffuse CAD, with a high specificity and reasonable sensitivity.
The mechanical monster and discourses of fear and fascination in the early history of the computer
Authors: Grenham Hannah
Published: November 2020

This article explores the concept of monstrosity in relation to the development of digital computers during the 1950s in the United States. Discourse analysis of public representations of early digital computers reveals a consistent appropriation of monstrosity as a metaphor to capture cultural fears of human-mechanical hybridity and technological autonomy. Deconstructing the development and application of this metaphor provides valuable insight into cultural attitudes about computers during this period. Through this analysis, the development of the computer appears as simultaneously following its own unique trajectory while also coinciding with broader trends in the cultural histories of new technologies. In particular, the example of the computer epitomises a dichotomy of fear and fascination, which is frequently seen in response to new technologies. Specific examples of early computers that are considered include ENIAC, WHIRLWIND, and UNIVAC. The public representation of and responses to each of these machines demonstrates a fundamental division between admiration at their technical application and concern over their apparently unlimited potential. This dichotomy is identified particularly through examination of contemporaneous popular cultural representations. Images of monstrosity are also shown to be consistent in these public representations, with rhetoric focusing in particular on anthropomorphic machines and human-mechanical hybridity. As a result, the fears of scientific creation encapsulated by Shelley’s depiction of Frankenstein’s monster can be seen to play out over a century later through the ‘mechanical monsters’ of the 1950s United States.
Deep level transient spectroscopy investigation of ultra-wide bandgap (2̄01) and (001) β-Ga2O3
Authors: Montes Jossue , Kopas Cameron , Chen Hong , Huang Xuanqi , Yang Tsung-han , Fu Kai , Yang Chen , Zhou Jingan , Qi Xin , Fu Houqiang , Zhao Yuji
Published: November 2020

This work reports on a comprehensive examination of the electrical and thermal properties of vertical Schottky diodes fabricated on (2¯01)- and (001)-oriented samples of β-Ga2O3. The temperature-dependent current–voltage (I–V) and capacitance–voltage (C–V) data were gathered and analyzed down to 60 K. Deep level transient spectroscopy (DLTS) was used to study bulk and interface defects in the two materials from approx. 325 K down to 60 K. In the bulk (2¯01) material, an electron trap was observed at EC−0.46 eV, with a capture cross section of 1.6 × 10−14 cm2 and a lambda-corrected maximum trap density of 9.08 × 1015 cm−3. These results and others indicate that the electron trap is a strong candidate for the well-known E1 defect in β-Ga2O3 based on recent investigations. Additionally, in the (2¯01) material, the smooth modulation typical of interface states is evident at temperatures below 275 K. The (001) samples manifested what is likely the E2* electron trap at EC−0.68 eV, with a capture cross section of 1.64 × 10−15 cm2 and a lambda-corrected maximum trap density of 8.85 × 1015 cm−3. The presence of the E2* defect, in particular, is a contrast to the findings of recent DLTS investigations on β-Ga2O3, which report that E2* emerged only after low-energy proton irradiation. These results help to further map out the defect signatures found in β-Ga2O3 materials, which are of vital importance in the design and fabrication of future β-Ga2O3 devices.
Effect of density of a sphere launched vertically in water on the water-surface behavior and sphere motion in air
Authors: Takamure K. , Uchiyama T.
Published: November 2020

Submerged solid spheres with specific gravities relative to water ranging from 1.36 to 7.93 were launched vertically upward toward the free surface of calm water. The motion of each sphere and the behavior of the water surface were investigated from the time the sphere passed through the calm water surface until it attained its maximum displacement position. The energy lost in the interaction between the sphere and the water surface (i.e., the interfacial containing energy Eo) was estimated from energy conservation. A larger Eo at the maximum displacement position of the sphere led to a larger increase in the height and width of the interfacial water sheet where the upper side of the sphere intersected with the free surface of calm water. This result corresponded to the result obtained by changing the submergence depth, as reported by Takamure and Uchiyama [“Air–water interface dynamics and energy transition in air of a sphere passed vertically upward through the interface,” Exp. Therm. Fluid Sci. 118, 110167 (2020)]. This aspect suggests that the characteristics of the interfacial water sheet are the dominant parameters influencing Eo. The presented findings can facilitate the determination of parameters to model the water exit problem.
Estimating reciprocal partition functions to enable design space sampling
Authors: Albaugh Alex , Gingrich Todd R.
Published: November 2020

Reaction rates are a complicated function of molecular interactions, which can be selected from vast chemical design spaces. Seeking the design that optimizes a rate is a particularly challenging problem since the rate calculation for any one design is itself a difficult computation. Toward this end, we demonstrate a strategy based on transition path sampling to generate an ensemble of designs and reactive trajectories with a preference for fast reaction rates. Each step of the Monte Carlo procedure requires a measure of how a design constrains molecular configurations, expressed via the reciprocal of the partition function for the design. Although the reciprocal of the partition function would be prohibitively expensive to compute, we apply Booth’s method for generating unbiased estimates of a reciprocal of an integral to sample designs without bias. A generalization with multiple trajectories introduces a stronger preference for fast rates, pushing the sampled designs closer to the optimal design. We illustrate the methodology on two toy models of increasing complexity: escape of a single particle from a Lennard-Jones potential well of tunable depth and escape from a metastable tetrahedral cluster with tunable pair potentials.
Coarse-grained implicit solvent lipid force field with a compatible resolution to the Cα protein representation
Authors: Ugarte La Torre Diego , Takada Shoji
Published: November 2020

Biological membranes have been prominent targets for coarse-grained (CG) molecular dynamics simulations. While minimal CG lipid models with three beads per lipid and quantitative CG lipid models with >10 beads per lipid have been well studied, in between them, CG lipid models with a compatible resolution to residue-level CG protein models are much less developed. Here, we extended a previously developed three-bead lipid model into a five-bead model and parameterized it for two phospholipids, POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) and DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine). The developed model, iSoLF, reproduced the area per lipid, hydrophobic thickness, and phase behaviors of the target phospholipid bilayer membranes at the physiological temperature. The model POPC and DPPC membranes were in liquid and gel phases, respectively, in accordance with experiments. We further examined the spontaneous formation of a membrane bilayer, the temperature dependence of physical properties, the vesicle dynamics, and the POPC/DPPC two-component membrane dynamics of the CG lipid model, showing some promise. Once combined with standard Cα protein models, the iSoLF model will be a powerful tool to simulate large biological membrane systems made of lipids and proteins.
Self-generated persistent random forces drive phase separation in growing tumors
Authors: Sinha Sumit , Thirumalai D.
Published: November 2020

A single solid tumor, composed of nearly identical cells, exhibits heterogeneous dynamics. Dynamics of cells in the core is glass-like, whereas those in the periphery undergoes diffusive or super-diffusive behavior. Quantification of heterogeneity using the mean square displacement or the self-intermediate scattering function, which involves averaging over the cell population, hides the complexity of the collective movement. Using the t-distributed stochastic neighbor embedding (t-SNE), a popular unsupervised machine learning dimensionality reduction technique, we show that the phase space structure of an evolving colony of cells, driven by cell division and apoptosis, partitions into nearly disjoint sets composed principally of the core and periphery cells. The non-equilibrium phase separation is driven by the differences in the persistence of self-generated active forces induced by cell division. Extensive heterogeneity revealed by t-SNE paves the way toward understanding the origins of intratumor heterogeneity using experimental imaging data.
Effects of adatom mobility and Ehrlich–Schwoebel barrier on heteroepitaxial growth of scandium nitride (ScN) thin films
Authors: Rao Dheemahi , Biswas Bidesh , Acharya Shashidhara , Bhatia Vijay , Pillai Ashalatha Indiradevi Kamalasanan , Garbrecht Magnus , Saha Bivas
Published: November 2020

Scandium nitride (ScN) is an emerging rock salt indirect bandgap semiconductor and has attracted significant interest in recent years for thermoelectric energy conversion, as a substrate for defect-free GaN growth, as a semiconducting component in single-crystalline metal/semiconductor superlattices for thermionic energy conversion, as well as for Al1−xScxN-based bulk and surface acoustic devices for 5G technologies. Most ScN film growth traditionally utilizes physical vapor deposition techniques such as magnetron sputtering and molecular beam epitaxy, which results in stoichiometric films but with varying crystal quality, orientations, microstructures, and physical properties. As epitaxial single-crystalline ScN films with smooth surfaces are essential for device applications, it is important to understand the ScN growth modes and parameters that impact and control their microstructure. In this Letter, we demonstrate that large adatom mobility is essential to overcome the Ehrlich–Schwoebel (E–S) and grain boundary migration barriers and achieve defect (voids, dislocations, stacking faults, etc.)-free single-crystalline ScN films. Using the substrate temperature to tune adatom mobility, we show that nominally single-crystalline ScN films are achieved when the homologous temperature is higher than ∼0.3. For homologous temperatures ranging from 0.23 to 0.30, ScN films are found to exhibit significant structural voids in between pyramidal growth regions with multiple in-plane orientations resulting from additional lateral growth off the facets of the pyramids and broken epitaxy after ∼80 nm of growth. The in-depth discussion of the growth modes of ScN presented here explains its varying electrical and optical properties and will help achieve high-quality ScN for device applications.
The rotational spectrum of H2S⋯HI and an investigation by ab initio calculations of the origins of the observed doubling of rotational transitions in both H2S⋯HI and H2S⋯F2
Authors: Suckley Andrew P. , Tew David P. , Legon Anthony C.
Published: November 2020

The rotational spectrum of the complex H2S⋯HI observed with a pulsed-jet, Fourier-transform microwave spectrometer shows that each rotational transition is split into a closely spaced doublet, a pattern similar to that observed earlier for the halogen-bonded complex H2S⋯F2. The origin of the doubling has been investigated by means of ab initio calculations conducted at the CCSD(T)(F12*)/cc-pVDZ-F12 level. Two paths were examined by calculating the corresponding energy as a function of two angles. One path involved inversion of the configuration at S through a planar transition state of C2v symmetry via changes in the angle ϕ between the C2 axis of H2S and the line joining the H and I nuclei [the potential energy function V(ϕ)]. The other was a torsional oscillation θ about the local C2 axis of H2S that also exchanges the equivalent H nuclei [the potential energy function V(θ)]. The inversion path is slightly lower in energy and much shorter in arc length and is therefore the favored tunneling pathway. In addition, calculation of V(ϕ) for the series of hydrogen- and halogen-bonded complexes H2S⋯HX (X = F, Cl, or Br) and H2S⋯XY (XY = Cl2, Br2, ClF, BrCl, or ICl) at the same level of theory revealed that doubling is unlikely to be resolved in these, in agreement with experimental observations. The barrier heights of the V(ϕ) of all ten complexes examined were found to be almost directly proportional to the dissociation energies De.
Interference of co-propagating Rayleigh and Sezawa waves observed with micro-focused Brillouin light scattering spectroscopy
Authors: Geilen Moritz , Kohl Felix , Nicoloiu Alexandra , Müller Alexandru , Hillebrands Burkard , Pirro Philipp
Published: November 2020

We use micro-focused Brillouin light scattering spectroscopy (BLS) to investigate surface acoustic waves (SAWs) in a GaN layer on a Si substrate at GHz frequencies. Furthermore, we discuss the concept of BLS for SAWs and show that the crucial parameters of SAW excitation and propagation can be measured. We investigate a broad range of excitation parameters and observe that Rayleigh and Sezawa waves are excited simultaneously at the same frequency. Spatially resolved measurements of these co-propagating waves show a periodic pattern, which proves their coherent interference. From the periodicity of the spatial phonon patterns, the wavevector difference between the two waves has been identified and compared to the dispersion relation. The appearance of Sezawa waves related to the finite thickness of the piezoelectric substrate leads to acoustic fields with a time-independent spatial variation similar to the situations realized using counter-propagating waves. This periodicity can have an influence on experimental results in angular momentum conversion experiments, for example, via magneto-elastic fields in hybrid-SAW-structures with additional magnetic layers.
Ligand structure and adsorption free energy of nanocrystals on solid substrates
Authors: Pham Matthew , Travesset Alex
Published: November 2020

We present an investigation on the absorption of alkylthiolated nanocrystals on a solid substrate. We calculate adsorption free energies and report a number of effects induced by the substrate. Nearest neighbor distances and bonding free energies are significantly different than for a free floating case, there is a weakening of bonding free energies among nanocrystals, and the adsorption is manifestly anisotropic, i.e., stronger along certain directions of the nanocrystal core. We contend that this last result accounts for the Bain transition (fcc → bcc) observed in experimental results. We report the presence of vortices induced by the substrate, which explain the increased nearest neighbor distance among nanocrystals, which is in excellent quantitative agreement with experimental results and with the predictions of the Orbifold Topological Model. Implications for the assembly of nanostructures and future experiments are also discussed.
Machine learning for vibrational spectroscopy via divide-and-conquer semiclassical initial value representation molecular dynamics with application to N-methylacetamide
Authors: Gandolfi Michele , Rognoni Alessandro , Aieta Chiara , Conte Riccardo , Ceotto Michele
Published: November 2020

A machine learning algorithm for partitioning the nuclear vibrational space into subspaces is introduced. The subdivision criterion is based on Liouville’s theorem, i.e., the best preservation of the unitary of the reduced dimensionality Jacobian determinant within each subspace along a probe full-dimensional classical trajectory. The algorithm is based on the idea of evolutionary selection, and it is implemented through a probability graph representation of the vibrational space partitioning. We interface this customized version of genetic algorithms with our divide-and-conquer semiclassical initial value representation method for the calculation of molecular power spectra. First, we benchmark the algorithm by calculating the vibrational power spectra of two model systems, for which the exact subspace division is known. Then, we apply it to the calculation of the power spectrum of methane. Exact calculations and full-dimensional semiclassical spectra of this small molecule are available and provide an additional test of the accuracy of the new approach. Finally, the algorithm is applied to the divide-and-conquer semiclassical calculation of the power spectrum of 12-atom trans-N-methylacetamide.