bluuebunny/crossref_metadata_2025 huggingface dataset:
Sustainability method organizational and technological decisions in the construction of industrial complexes
Authors: Mukhametzyanov Zinur , Oleinik Pavel
Published: May 2021

The task is to develop a mechanism for the implementation of organizational and technological solutions in the construction of industry complexes. The action of the mechanism is based on the relationship of the parameters of organizational and technological design and construction decisions, which increases the reliability of the implementation of decisions. A conceptual approach has been identified to solve the problem of improving the reliability of organizational and technological solutions in the construction of industry complexes. A model of the technology for erecting an object using estimates of technological dependencies is developed, which is the technological basis for making organizational and technological decisions. The algorithm for the implementation of organizational and technological solutions in the construction of industrial complexes is determined. The proposed mechanism provides an increase in the multiplicity of ways to select the optimal set of organizational and technological solutions due to a significant expansion of the zone of feasible solutions and thereby solves the problem of ensuring the stability and reliability of organizational and technological solutions in the construction of industrial complexes.
Development of process control and technical documentation for the construction of residential buildings and structures from monolithic reinforced concrete
Authors: Fahratov Mukhammet , Oleynik Pavel , Kurenkov Oleg
Published: May 2021

One of the main tasks of the foreman at the construction site is the proper execution of technical and as-built documentation. As-built technical documentation is an integral part of construction production, which is necessary to confirm the quality and scope of work performed. In the event of accidents both during the construction of the facility and during its operation, as-built documentation is considered first to identify the reasons. It is also presented in the process of putting the object into operation. A foreman at a construction site needs to solve many problems: from ordering materials and controlling the production of construction and installation works to preparingas-built and reporting documentation for each completed stage of work. At the same time, as practice shows, a shortage of staffing to solve all the necessary tasks has been identified. In this regard, some companies resort to additional human resources for engineering and technical personnel from third parties. The task of the formation and functioning of the process of staffing mainly consists of creating a system for management regulation and providing this system with highly qualified professional personnel. This task is especially acute in the case of organizational coordination of construction management regulation. Based on this, there is a steady trend towards the growth of engineering corporations specializing in the complex provision of services for organizational coordination and management regulation. The selection of a professional construction organizer as an object of construction and investment activity imposes special requirements on the formation of an effective system of construction management regulation. The staffing level is expressed in accordance with the data on the composition of administrators, employees or the auxiliary personnel of a systematized configuration of management regulation with the number provided by the staffing table established in the process of organizational design or strategic planning process. The provisions considered in the paper make it possible to identify the actual availability of workers at all stages of management regulation, including the possibility of eliminating the shortage of engineering and technical personnel by rearranging company’s own personnel, namely, to form a reserve for promotion, provide for retraining or additional training of the relevant groups of workers. In this case, the basis for the interaction of construction organizers and owners of labor resources is the process control and technical documentation.
Organizational and technological risks during the formation of clusters in megapolis
Authors: Semenenko Mikhail , Dral Stepan
Published: May 2021

The paper presents the characteristics of the risks in the formation of residential clusters in a megalopolis. The main goal of the model of clusters of integrated urban development is the high efficiency of its functioning and implementation. Such a development model allows simultaneously realizing many goals: economic, social, technological, and also allows monitoring various construction parameters and controlling them at all stages of construction production. The paper gives a definition of risks in construction, a classification of the risks of cluster formation, and also provides methods for their assessment and control. In addition to theoretical data, the paper provides examples of situations both in Russia and abroad.
Comparative analysis of simulation environments for a virtual testing ground to measure vibration and acoustic emissions of designed flying objects
Authors: Abramkina Kristina , Zhilenkova Elena , Borisenko Vladislav
Published: May 2021

The article deals with an important issue of creating virtual test grounds. The problem of measuring vibrations and acoustic emissions of designed objects of the aircraft industry, etc is studied. Thus, for example, one of the important tests of the coaxial helicopter at the development stage is the assessment of the impact of manufacturing tolerances on fuselage vibrations. The general problems of modeling and control of the acoustic field, the measurement of the acoustic emission of objects are considered. The research results can be used to solve the problems of creating virtual test grounds and other digital systems, where the assessment of the behavior of a complex object is made on the basis of its digital twin or, in general, on a mathematical or computer model. The introduction of such systems can significantly reduce financial costs when creating a product, increase quality of designed systems and predict their behavior under certain conditions without expensive testing.
Load distribution method in helicopter blade multibody dynamics system
Authors: Didenko Anton , Borisenko Vladislav , Leoro Jose
Published: May 2021

The paper focuses on the loads applied to the helicopter blade cross-sections in the multibody dynamics system. The main objective is to simplify the blade aerodynamics calculation and avoid time-consuming CFD methods. For this reason, the way of computing blade aerodynamics is proposed by using multibody dynamics methods with a linear-elastic blade model. As the primary tool for further research, the MCS Adams software package is selected. Splitting the main rotor blade into a finite number of sections, each having its own average value of installation and coning angles, simplifies the calculation. Afterward, expressions for the total flow velocity around the blade section and its angle of attack are obtained through vector operations. This provides a measure of aerodynamic forces acting on each section in its cross-sectional coordinate system. In conclusion, the article provides the formalized method of aerodynamic force distribution between blade sections in the multibody model as well as the correlation between the flow coordinate system and the blade chord coordinate system.
Gypsum polymer materials in construction
Authors: Bessonov Igor , Zhukov Aleksey , Efimov Boris , Gorbunova Elina , Govryakov Ilya
Published: May 2021

The modern level of technological development involves the use of traditional materials modified with additives of various types and functional purposes, as well as composite materials allowing to obtain a product with improved properties. Expanding the area of application of products based on gypsum for facade systems involves the creation of weather-resistant, and, first of all, waterproof materials based on gypsum polymers. The purpose of the experiment, the results of which are presented in the article, was to assess the possibility of using polycondensation polymers as a component of gypsum polymer, to model the properties of the material and to evaluate its characteristics as a result of climatic and humidity influences. The modeling and optimization of gypsum polymer properties were based on statistical methods as well as methods of mathematical analysis of functions of several variables. The assessment of the water resistance of gypsum polymer samples was carried out under test conditions in an open reservoir with an almost unlimited reaction capacity of the medium. The weather resistance was checked according to the results of tests in a climatic chamber. Experiments have shown that the strength of samples with 20% modified melamine-formaldehyde resin in compression and in bending for 80 days of storage in air increases by 30% and 25%, respectively. The compressive strength is 60 MPa, and the flexural strength is 12 MPa. Gypsum polymer has high frost resistance up to 150 cycles of alternate freezing and thawing. The result of the research was the confirmation of the possibility of using polycondensation resins and the foundations of the method for selecting the composition of the gypsum polymer were developed. The results obtained can be used in the development of the technology of gypsum polymer products, and, in particular, piece products (building cladding tiles).
Convergence of employers’ and students’ expectations in the educational environment of the agricultural university
Authors: Razinkina Elena , Zima Elena , Pozdeeva Elena , Evseeva Lidiya , Tanova Anna
Published: May 2021

In the digital age, a modern university is becoming a driver for the development of complex multi-agent ecosystems and a supplier of a new type of human resources, characterized not only by intellectual potential and high qualifications but also by such qualities in demand in the labor market as creativity, critical thinking, the need for continuous learning and “agency”, which is understood as the ability to self-organize and proactivity [1]. The education system and universities themselves face challenges that force us to turn to the once-actual ideas of integration and convergence, which can fulfill the increased need to achieve synergy effects and multiplier indicators that contribute to achieving high ratings in a short time. It is convergent processes that lie at the heart of the developing communicative space of the university today, whose activities are based on the intersection of the interests and expectations of various actors, which are implemented on multi-agent platforms. At the same time, the opportunities that are opening up due to the rapid introduction of digital technologies require restructuring the space of interactions between subjects towards the formation of flexible forms, network models, alliances, virtual corporations, connecting clusters built on the principles of active cooperation, exchange of best practices and developments.
Industrial sector engineering staff development systems
Authors: Armashova-Telnik Galina , Zubkova Anna , Melnichenko Alexandra , Semenova Veronika , Sokolova Polina , Terentyeva Yulia
Published: May 2021

This article discusses methods for the employees quality and performance improvement in the electric power industry enterprises. The characteristics of the factors influencing the development of personnel are given. The foreign experience of corporate training is analyzed, which identifies ways to improve labor activity, maintain labor discipline, increase the level of labor motivation, develop corporate culture and increase the employee loyalty at industrial enterprises. The structure of personnel training methods at the enterprise is schematically presented. The article substantiates the need for the formation of a qualified human resource that provides the company with the growth of economic indicators of production activity, a high degree of competitiveness in the industry market, and a positive image of the organization
Analysis of access to the electricity transmission network using information technologies in some countries
Authors: Azieva Gulmira , Kerimkhulle Seyit , Turusbekova Umut , Alimagambetova Ainagul , Niyazbekova Shakizada
Published: May 2021

The role of information technology is especially great in strategic sectors of the economy, one of which is energy. After all, the more complex the product, the more acutely it needs more automation of the processes taking place in it. The main informational tasks of power generation are the automation of technological process systems and control over the installed equipment. The main factor that influences the development of information technologies in the energy sector in Kazakhstan is the need for high-tech reforms in this sector of the economy. Thus, the development of IT technologies in the energy sector, like any other industry, will lead to the automation of the entire complex, which will entail its more efficient operation in every sense. The article provides an overview of works devoted to the problem of access to the electricity transmission network in Africa, India, Turkey, etc.
Dewaxing models digitalization in the mathematical model of winter diesel fuel production
Authors: Nikonorov Valentin , Kutuzov Andrei , Nikonorov Viktor , Bagaeva Irina , Letta Anna
Published: May 2021

The climatic features of Russia, as well as the need for the development of the Arctic and the Great Northern Sea Route, require an increase in the production of winter diesel fuel. The object of the study is obtaining winter diesel fuel. The subject of the study is digitalizing oil-refining processes by building the mathematical model of winter diesel fuel production for the case of combining dewaxing regimes taking into account the logistical aspect. Main research methods: retrospective data analysis, synthesis, comparison, optimization theory methods. A literary review was carried out, the main methods for improving the low-temperature properties of winter diesel fuel were revealed. Study hypothesis: a combination of dewaxing regimes will increase the yield of denormalizate and, accordingly, winter diesel fuel. The authors for each mode of dewaxing compiled a mathematical model. Then, the authors constructed a mathematical model of obtaining winter diesel fuel for a combination of dewaxing regimes and taking into account the logistical aspect. The obtained mathematical model can be used to obtain the required amount of winter diesel fuel with compliance with quality requirements and taking into account the logistical aspect.
Studying the process of freons mixture separation on a structured packing Sultzer 500X
Authors: Pavlenko Aleksandr , Zhukov Vladimir , Pecherkin Nikolay , Slesareva Ekaterina , Boyadjiev Christo , Dzhonova-Atanasova Daniela
Published: May 2021

Structured packings are widely used in distillation columns to separate various types of mixtures. These packings have an ordered structure, which ensures more uniform conditions for interaction of counter-current flows of liquid and vapor than in the random packings and have a small hydraulic resistance. Nevertheless, in columns with a diameter of more than 0.5 m, formation of large-scale non-uniformity in distribution of liquid and vapor flow parameters over the packing cross-section is observed. In this work, experimental data on formation of large-scale non-uniformity in the temperature field over the cross-section of the Sulzer 500X packing, as well as on the efficiency of mixture separation and the pressure drop across the packing were obtained. The experiments were carried out with separation of R114/R21 freon mixture on a 10-layer structured packing Sulzer 500X with a diameter of 0.6 m and a height of 2.2 m. Experimental data were compared with the results obtained earlier for a structured packing Mellapack 350.Y with a diameter of 0.9 m and a height of 2.1 m. The presented experimental data will be used to construct and verify a new model of mass transfer and efficiency of mixture separation in the large-scale distillation packed columns.
Increasing and intensification of the technology of purification of natural gas by composite absorbents
Authors: Aripdjanov Oybek , Tirkasheva Xurshida
Published: May 2021

Today, the urgent task is the synthesis of new nanostructured composite sorbents used for the complete utilization of various wastes of oil and gas refineries, improving the technology of processes for cleaning natural and tail exhaust gases from acidic impurities, increasing the stability of the physicochemical properties of sorbents and improving the environmental conditions for processing secondary absorbents oil and gas refineries. Recently, in the world in oil and gas processing industrial enterprises, the main attention has been focused on the search for methods for purifying natural and waste gas from organic compounds of sulfur, mercaptans, carbonyl sulfide (COS), carbon disulfide (CS2) and sulfides (RSR), as well as the creation of new types of highly effective composite adsorbents for gas purification.
Development of a methodological tool for internal control to increase the efficiency of use of fixed assets
Authors: Zakirova Alsou , Zaugarova Evgenia , Klychova Guzaliya , Sungatullina Rashida , Klinova Elena
Published: May 2021

The basis of the material and technical base of the operation of enterprises are fixed assets. Therefore, the effective organization of accounting and internal control of operations with fixed assets is one of the important tasks facing the management of any enterprise. The purpose of the article consists in development of methodical toolkit of internal control for increase in efficiency of use of the fixed assets. For the development of theoretical bases the article develops the conceptual model of internal control of operations with the fixed assets, which is a logically interconnected system including basic elements of internal control such as purpose, objectives, functions, object, subject, tools, sources of information, regulatory framework, evidence collection, execution of audit results and development of recommendations. In order to improve methodological support, the working papers of internal control were developed in the article. The proposed working documents can be used to identify critical areas of accounting with a high level of risk and determine the means of control necessary to conduct control procedures; to assess the organization and functioning of internal control, the effectiveness of employees responsible for the safety of fixed assets; formation of the information base for management decisions; assessment of risks associated with the acquisition and use of fixed assets.
Das schöne, glatte Bein: Haarentfernung durch Laser und lichtbasierte Verfahren
Authors: Braun Tatjana , Kleimann Pia , Meissner Markus , Kaufmann Roland , Valesky Eva Maria
Published: May 2021

Die Fotoepilation zählt zu den meistgefragten nichtchirurgischen Eingriffen in der ästhetischen Dermatologie. Haarlose, glatte Beine gelten dabei als Schönheitsideal.

Fotoepilation mittels Laser oder hochenergetischer Blitzlampen (sog. Intensed-Pulsed-Light-Geräte) stellt ein sicheres und effektives Verfahren dar. Der Wirkmechanismus beruht auf dem Prinzip der selektiven Fotothermolyse, wobei eine gezielte thermische Schädigung pigmentierter Haarfollikel unter Schonung des umliegenden Gewebes erfolgt. Melaninpigment des Haarschaftes absorbiert als Zielchromophor Licht eines speziellen Wellenlängenspektrums und führt durch Wärmediffusion zur Schädigung der für das Haarwachstum wichtigen Stammzellen im äußeren Haarwurzelschaft.

Patienten müssen über die Notwendigkeit wiederholter Behandlungen sowie den häufig nur partiellen und temporären Haarverlust aufgeklärt werden. Dunkle Terminalhaare bei hellen Hauttypen lassen sich effektiv entfernen. Bei dunklen Hauttypen besteht aufgrund des erhöhten epidermalen Melaninvorkommens ein erhöhtes Risiko für Nebenwirkungen wie Verbrennungen, Dyspigmentierungen und Narben. Sehr feine, helle oder rote Haare lassen sich kaum mit konventionellen Fotoepilationsverfahren entfernen. Haarentfernungsgeräte für den Heimgebrauch sind eine kostengünstige, einfach anzuwendende Alternative, weisen aber im Vergleich zur professionellen Fotoepilation eine geringere Effektivität auf.
Asbestos Exposure and Ovarian Cancer – a Gynaecological Occupational Disease. Background, Mandatory Notification, Practical Approach
Authors: Nowak Dennis , Schmalfeldt Barbara , Tannapfel Andrea , Mahner Sven
Published: May 2021

In 2017, ovarian cancer due to asbestos exposure was designated a new, and thereby the first, gynaecological occupational disease in Germany. Asbestos is a naturally occurring mineral fibre with an annual usage in Germany of 160 000 – 180 000 metric tonnes in the 1960s and 1970s. The carcinogenicity of asbestos for the target organs lungs, larynx, pleura including pericardium, and peritoneum including tunica vaginalis testis has been clearly established for many years. Recent meta-analyses of data from cohort studies have demonstrated that the risk of ovarian cancer roughly doubles in women with occupational exposure to asbestos. Since the group of people with double the risk of developing lung cancer due to work-related asbestos exposure has a 2.25-fold increased risk of mortality from ovarian cancer on average, work-related ovarian cancer has been assigned the same recognition requirements as in occupational lung (and laryngeal) cancer. Thus, gynaecologists must obtain
a thorough history of occupational exposure to asbestos, even if it may have taken place long in the past. The law mandates that suspected such cases must be reported to the Statutory Accident Insurance carrier or the State Occupational Safety and Health Agency.
„Also Stress ist jeden Tag“ – Ursachen und Bewältigung von arbeitsbedingten Fehlbelastungen im Krankenhaus aus Sicht der Beschäftigten. Eine qualitative Studie
Authors: Stiawa Maja , Peters Martin , Mulfinger Nadine , Krumm Silvia , Worringer Britta , Maatouk Imad , Küllenberg Janna , Junne Florian , Genrich Melanie , Gündel Harald , Puschner Bernd
Published: May 2021

Ziel der Studie Befragung von Mitarbeitern im Krankenhaus zu arbeitsbedingten Fehlbelastungen und Stressfolgen sowie Konsequenzen für Interventionen zur Stressreduktion am Arbeitsplatz.

Methodik Es wurden 6 Fokusgruppen und 7 semistrukturierte Interviews mit 34 Krankenhausmitarbeitern durchgeführt, welche inhaltsanalytisch ausgewertet wurden.

Ergebnisse Mitarbeiter berichteten von Stressfolgen durch Personalmangel, hohes Arbeitsaufkommen, fehlende Rückzugs- und Versorgungsmöglichkeiten, fehlende Absprachen, intransparente Arbeitsabläufe, Teamkonflikte und fehlende Wertschätzung. Berichtete Faktoren, die zur Reduktion von Stressfolgen führten, waren soziale Unterstützung, Arbeitszeitreduktion, Sport und Entscheidungskompetenzen.

Schlussfolgerung Interventionen zur Reduktion arbeitsbedingter Fehlbelastungen im Krankenhaus sollten sowohl berufsgruppenspezifische Interventionsangebote sowie organisationale Normen und strukturelle Rahmenbedingungen berücksichtigen.
Modeling synchronization in globally coupled oscillatory systems using model order reduction
Authors: Discacciati Niccolò , Hesthaven Jan S.
Published: May 2021

We construct reduced order models for two classes of globally coupled multi-component oscillatory systems, selected as prototype models that exhibit synchronization. These are the Kuramoto model, considered both in its original formulation and with a suitable change of coordinates, and a model for the circadian clock. The systems of interest possess strong reduction properties, as their dynamics can be efficiently described with a low-dimensional set of coordinates. Specifically, the solution and selected quantities of interest are well approximated at the reduced level, and the reduced models recover the expected transition to synchronized states as the coupling strengths vary. Assuming that the interactions depend only on the averages of the system variables, the surrogate models ensure a significant computational speedup for large systems.
A resilience concept based on system functioning: A dynamical systems perspective
Authors: Schoenmakers Sarah , Feudel Ulrike
Published: May 2021

We introduce a new framework for resilience, which is traditionally understood as the ability of a system to absorb disturbances and maintain its state, by proposing a shift from a state-based to a system functioning-based approach to resilience, which takes into account that several different coexisting stable states could fulfill the same functioning. As a consequence, not every regime shift, i.e., transition from one stable state to another, is associated with a lack or loss of resilience. We emphasize the importance of flexibility—the ability of a system to shift between different stable states while still maintaining system functioning. Furthermore, we provide a classification of system responses based on the phenomenological properties of possible disturbances, including the role of their timescales. Therefore, we discern fluctuations, shocks, press disturbances, and trends as possible disturbances. We distinguish between two types of mechanisms of resilience: (i) tolerance and flexibility, which are properties of the system, and (ii) adaptation and transformation, which are processes that alter the system’s tolerance and flexibility. Furthermore, we discuss quantitative methods to investigate resilience in model systems based on approaches developed in dynamical systems theory.
Understanding the effects of neutron scattering for neutron-yield-isotropy measurements at the NIF
Authors: Hahn K. D. , Bionta R. M. , Khater H. , Henry E. A. , Moore A. S. , Schlossberg D. J. , Barker D. A. , Casco E. R. , Ehrlich R. B. , Divol L. , Gjemso J. M. , Golod T. B. , Grim G. P. , Hartouni E. P. , Jeet J. , Kerr S. M.
Published: May 2021

Neutron-yield diagnostics at the NIF have been upgraded to include 48 detectors placed around the NIF target chamber to assess the DT-neutron-yield isotropy for inertial confinement fusion experiments. Real-time neutron-activation detectors are used to understand yield asymmetries due to Doppler shifts in the neutron energy attributed to hotspot motion, variations in the fuel and ablator areal densities, and other physics effects. In order to isolate target physics effects, we must understand the contribution due to neutron scattering associated with the different hardware configurations used for each experiment. We present results from several calibration experiments that demonstrate the ability to achieve our goal of 1% or better precision in determining the yield isotropy.
A line-scanning chromatic confocal sensor for three-dimensional profile measurement on highly reflective materials
Authors: Hu Hao , Mei Shuang , Fan Liming , Wang Huigang
Published: May 2021

We developed a practical Line-Scanning Chromatic Confocal Sensor (LSCCS) that can generate three-dimensional (3D) points with up to 32 000/s with a high-precision motion device. An optical route of line-scanning confocal spectroscopy is designed and verified by simulation. The LSCCS is composed of a white laser source, a chromatic confocal optics, and a self-developed spectrometer. The chromatic confocal optics consists of a slit, a chromatic lens (dispersive objective lens), and a beam splitter, and the spectrometer consists of an adjustable slit, a collimating lens, a blazed grating, a focusing lens, a CMOS, and an image processing circuit. The slit and the chromatic lens are designed for a line focus, and the polarizing beam splitter is selected to maximize the white light power collected by the CMOS. The motion device is made to realize the full-field 3D scanning. The key algorithms involved are developed to accurately restore the peak wavelength that includes the position information of the measured surface from the collected spectral image. Theoretical analysis and simulation showed that the corresponding resolutions in Z (depth), X (direction of optical fibers layout), and Y (direction of line-scanning) directions are 0.6, 10, and 5 µm, with a line length of 8 mm and a depth field of 2.4 mm. Experimental results showed that the sensor produces a measurement accuracy of 0.886 µm and a scanning speed of 90 fps. It is of great significance for the accurate measurement of the 3D profile and thickness on the highly reflective materials in the fields of optics, semiconductors, or micromechanics.
Active learning and relevance vector machine in efficient estimate of basin stability for large-scale dynamic networks
Authors: Che Yiming , Cheng Changqing
Published: May 2021

The interconnectivity between constituent nodes gives rise to cascading failure in most dynamic networks, such as a traffic jam in transportation networks and a sweeping blackout in power grid systems. Basin stability (BS) has recently garnered tremendous traction to quantify the reliability of such dynamical systems. In power grid networks, it quantifies the capability of the grid to regain the synchronous state after being perturbated. It is noted that detection of the most vulnerable node or generator with the lowest BS or N−1 reliability is critical toward the optimal decision making on maintenance. However, the conventional estimation of BS relies on the Monte Carlo (MC) method to separate the stable and unstable dynamics originated from the perturbation, which incurs immense computational cost particularly for large-scale networks. As the BS estimate is in essence a classification problem, we investigate the relevance vector machine and active learning to locate the boundary of stable dynamics or the basin of attraction in an efficient manner. This novel approach eschews the large number of sampling points in the MC method and reduces over 95% of the simulation cost in the assessment of N−1 reliability of power grid networks.
Free energy of ion–electron plasmas: Comparing calculations to experiments
Authors: Shavlov A. V. , Dzhumandzhi V. A. , Yakovenko A. A.
Published: May 2021

The free energy of charged particles in a two-temperature model of an ion–electron plasma has been determined using the Debye–Hückel method. For this purpose, self-consistent potentials of charged particles were calculated on the basis of the numerical solution to the Poisson–Boltzmann equation, and the potential acting on a particle from the plasma was determined. We show that all the plasma components, as well as the plasma as a whole, have local minima in free energy at certain concentration and temperature values, i.e., they can remain in metastable states. Correlations have been established between the metastable-state calculations and known experimental data on contracted and arc discharge plasmas, as well as more exotic plasmas, plasmoids, and ball lightning plasmas.
Electric field mediated droplet spheroidizing in an extensional flow
Authors: Liu Xiangdong , Li Lei , Yu Jingwen , Hao Guanqiu , Yu Wei , Chen Yongping
Published: May 2021

A 3D mathematical model coupling the phase-field model and the electric current model is applied to describing the DC electric control of droplet deformation in an extensional flow field. Based on this model, electric field mediated droplet spheroidizing in an extensional flow is explored, and the underlying electro-hydrodynamics is clarified. Regime diagrams are plotted to quantitatively recognize the operating regimes for different droplet morphologies, from which the critical electro-hydrodynamic criteria for droplet spheroidizing are summarized. In addition, the influence of electrophysical parameters of fluids on electric field mediated droplet spheroidizing is analyzed. It is indicated that the hydrodynamic forces imposed on the droplet from the pure extensional flow can be completely counterweighted by imposing a proper electric field, so as to realize spheroidizing of the droplet. Within the scope of the current investigation, the critical electric capillary number (CaE) for droplet spheroidizing is found to have linear relationship with the hydrodynamic capillary number (Ca), which can be expressed as CaE = aCa. Specifically, the linear coefficient, a, decreases with increment of RS (i.e., the product of conductivity ratio and permittivity ratio between the droplet and continuous phase) when RS > 1, while it decreases with decreasing RS when RS < 1. Compared with RS > 1, the critical CaE for droplet spheroidizing is generally smaller under RS < 1 for a given Ca, suggesting less electric effort is required to realize droplet spheroidizing.
Revisiting doping mechanisms of n-type organic materials with N-DMBI for thermoelectric applications: Photo-activation, thermal activation, and air stability
Authors: Bardagot Olivier , Aumaître Cyril , Monmagnon Anthony , Pécaut Jacques , Bayle Pierre-Alain , Demadrille Renaud
Published: May 2021

Understanding doping mechanisms is essential for optimizing the doping efficiency and rationally designing next generations of dopants and organic materials. Over the last few years, N-DMBI became a reference solution-processed n-type dopant, affording decent air-stability and record power factor for thermoelectric energy generation. Nevertheless, a complete description of doping mechanism including the activation conditions, the doping pathways, and possible side reactions is still lacking. In this work, we combined experimental and theoretical evidence to clarify the activation conditions of N-DMBI and elucidate the prevalent doping pathway depending on the dielectric constant of the medium. In polar media, direct doping via hydride H− transfer is largely dominant, while, in apolar media, singly occupied molecular orbital-mediated doping after H• release is thermodynamically favored. We show that N-DMBI can be activated not only by thermal annealing above 100 °C, but also by UV-light irradiation at low fluences even in thin films. Our findings stress the importance of working in strictly anoxic environment to avoid parasitic O2-mediated side reactions, even in the presence of a host.
A revisitation of White−Metzner viscoelastic fluids
Authors: Tseng Huan-Chang
Published: May 2021

The famous White–Metzner (WM) constitutive equation expresses a relatively simple nonlinear viscoelastic fluid of polymer melts. However, such a differential stress model, substantial with strong hyperbolic and singular problems, has hitherto always obtained unsatisfactory simulations of corner vortex in a typical contraction flow, especially for high Weissenberg numbers. A modified WM model useful for viscoelastic fluid computations is, therefore, proposed herein. As a validation, this model primarily fits the first normal stress difference for characterizing a fluid's elasticity, as well as shear viscosity and extensional viscosity. It is significant to discuss the vortex formation and growth, with the predicted vortex sizes in good agreement with the experimental data.
Efficiency of bulk perovskite-sensitized upconversion: Illuminating matters
Authors: VanOrman Zachary A. , Lackner Jens , Wieghold Sarah , Nienhaus Karin , Nienhaus G. Ulrich , Nienhaus Lea
Published: May 2021

Photon upconversion via triplet–triplet annihilation could allow for the existing efficiency limit of single junction solar cells to be surpassed. Indeed, efficient upconversion at subsolar fluences has been realized in bulk perovskite-sensitized systems. Many questions have remained unanswered, in particular, regarding their behavior under photovoltaic operating conditions. Here, we investigate the impact of repeated and continuous illumination on bilayer perovskite/rubrene upconversion devices. We find that variations of the underlying perovskite carrier recombination dynamics greatly impact the upconversion process. Trap filling and triplet sensitization are in direct competition: more saturated trap states in the perovskite and, thus, longer underlying perovskite photoluminescence lifetimes allow for an increased number of carriers to diffuse to the perovskite/rubrene interface and undergo charge extraction to the triplet state of rubrene. As a result, the upconversion efficiency is greatly influenced by the underlying trap density: the upconverted photoluminescence intensity increases by two orders of magnitude under continuous illumination for 4 h. This shows that the upconversion efficiency is difficult to define for this system. Importantly, these results indicate that perovskite-sensitized upconversion devices exhibit peak performance under continuous illumination, which is a requirement for their successful integration into photovoltaics to help overcome the Shockley–Queisser limit in single junction solar cells.
Factors influencing the development of violent pyroconvection. Part II: fire geometry and intensity
Authors: Badlan Rachel L. , Sharples Jason J. , Evans Jason P. , McRae Rick H. D.
Published: May 2021

Fire spread associated with violent pyrogenic convection is highly unpredictable and difficult to suppress. Wildfire-driven convection may generate cumulonimbus (storm) clouds, also known as pyrocumulonimbus (pyroCb). Research into such phenomena has tended to treat the fire on the surface and convection in the atmosphere above as separate processes. We used a numerical model to examine the effect of fire geometry on the height of a pyroconvective plume, using idealised model runs in a neutral atmosphere. The role of geometry was investigated because large areal fires have been associated with the development of pyroCb. Complementary results (detailed in Part I) are extended by considering the effect that fire shape can have on plume height by comparing circular, square, and rectangular fires of varying length and width, representing the difference between firelines and areal fires. Results reveal that the perimeter/area ratio influenced the amount of entrainment that the plume experiences and therefore the height to which the plume rises before it loses buoyancy. These results will aid in the prediction of blow-up fires (whereby a fire exhibits a rapid increase in rate of spread or rate of spread) and may therefore be useful in determining where fire agencies deploy their limited resources.
Nonparametric coalescent inference of mutation spectrum history and demography
Authors: DeWitt William S. , Harris Kameron Decker , Ragsdale Aaron P. , Harris Kelley
Published: May 2021

Significance

Population histories are encoded by genomic variation among modern individuals. Population genetic inference methods, all theoretically rooted in probabilistic population models, can recover complex demographic histories from genomic variation data. However, the mutation process is treated very simply in these models—usually as a single constant. Recent empirical findings show that the mutation process is complex and dynamic over a range of evolutionary timescales and thus, deserving of richer descriptions in population genetic models. Here, we show that complex mutation spectrum histories can be accommodated by extending classical theoretical tools. We develop mathematical optimization methods and software to infer both demographic history and mutation spectrum history, revealing human mutation signatures varying through time and global divergence of mutational processes.
A stress-responsive miRNA regulates BMP signaling to maintain tissue homeostasis
Authors: Mukherjee Sromana , Paricio Nuria , Sokol Nicholas S.
Published: May 2021

Significance

Adult stem cells maintain tissue homeostasis by rapidly replenishing cells lost from injury or tissue damage. We use the
Drosophila
adult intestine as a model tissue to identify a stress-responsive, tissue-specific microRNA (miRNA),
miR-958
, that is crucial for regulating intestinal stem cell number during homeostasis and in response to stress. We also show that this miRNA executes its function by modulating bone morphogenetic protein signaling by posttranscriptionally silencing the Cabut/KLF10/11 transcription factor. Furthermore, this miRNA is transiently down-regulated during stress to expand the stem cell number and thereby meet tissue demand. Overall, our study indicates that this tissue-specific, miRNA-mediated regulation of a core signaling pathway can serve as an effective strategy for controlling tissue regeneration.
Platelets orchestrate the resolution of pulmonary inflammation in mice by T reg cell repositioning and macrophage education
Authors: Rossaint Jan , Thomas Katharina , Mersmann Sina , Skupski Jennifer , Margraf Andreas , Tekath Tobias , Jouvene Charlotte C. , Dalli Jesmond , Hidalgo Andres , Meuth Sven G. , Soehnlein Oliver , Zarbock Alexander
Published: May 2021

Beyond hemostasis, platelets actively participate in immune cell recruitment and host defense, yet their potential in the resolution of inflammatory processes remains unknown. Here, we demonstrate that platelets are recruited into the lung together with neutrophils during the onset of inflammation and alongside regulatory T (T reg) cells during the resolution phase. This partnering dichotomy is regulated by differential adhesion molecule expression during resolution. Mechanistically, intravascular platelets form aggregates with T reg cells, a prerequisite for their recruitment into the lung. This interaction relies on platelet activation by sCD40L and platelet P-selectin binding to PSGL-1 on T reg cells. Physical platelet–T reg cell interactions are necessary to modulate the transcriptome and instruct T reg cells to release the anti-inflammatory mediators IL-10 and TGFβ. Notably, the presence of platelet–T reg cell aggregates in the lung was also required for macrophage transcriptional reprogramming, polarization toward an anti-inflammatory phenotype, and effective resolution of pulmonary inflammation. Thus, platelets partner with successive immune cell subsets to orchestrate both the initiation and resolution of inflammation.
Effects of HTL/ETL properties on the performance of (FAPbI3)0.85(MAPbBr3)0.15 perovskite solar cells
Authors: Mashhadi Seyyed Abadi Negar , Banihashemi Mehdi , Kashani Nia Alireza
Published: May 2021

Mixed cation perovskite solar cells (PSCs) have shown high stability over 1000 h under outdoor conditions. In this paper, we simulated fluorine-doped tin oxide/TiO2/(FAPbI3)0.85(MAPbBr3)0.15/ Spiro-OMeTAD solar cell as the base structure by SCAPS-1D software. We then studied the effects of E
V position of hole transport layer (HTL) and E
C position of electron transport layer (ETL) and carrier density of HTL and ETL, on the performance of the solar cells. Simulation results showed that the carrier density of HTL and ETL has outstanding effect on the performance of the mixed cation PSC through band alignment between the layers. Moreover, we studied the influence of defect density of ETL/perovskite and perovskite/HTL interface layers. According to simulation results, we predict that using Spiro-OMeTAD as HTL and Nb-doped TiO2 as ETL, that have shown capability of fabrication with PSCs, improves the power conversion efficiency to 19.75%.
Performance improvement in p-Type WS2 field-effect transistors with 1T phase contacts
Authors: Yang Yafen , Li Han , Gu Zhenghao , Chen Lin , Zhu Hao , Ji Li , Sun Qingqing
Published: May 2021

The non-ideal contact between the metal electrode and semiconducting channel has become one of the major bottlenecks degrading the performance of field-effect transistors (FETs) based on two-dimensional (2D) materials. The formation of the Schottky barrier prohibiting the carrier injection as well as the Fermi level pinning effect have a strong impact on the device performance. In this work, we fabricated a 2D WS2 FET device with engineered metallic 1T phase at the source/drain region by using Li intercalation method. As compared to the device with conventional 2H-WS2 channel, the engineered FET with a 2H-WS2/1T-WS2 junction has exhibited greatly improved performance such as over 10 times higher carrier mobility and steeper subthreshold slope. Such results have demonstrated the boosted carrier injection into the channel over the engineered metal contact as well as the reduced tunnel barrier width between the 2H/1T-WS2 junction. This can be attractive for the large-scale integration of the 2D devices towards high-performance and high-reproducibility nanoelectronics applications.
Nano-hillock formation on CaF2 due to individual slow Au-cluster impacts
Authors: Szabo Gabriel L , Lehner Markus , Bischoff Lothar , Pilz Wolfgang , Muckenhuber Helmut , Kentsch Ulrich , Aumayr Friedrich , Klingner Nico , Wilhelm Richard A
Published: May 2021

We present a direct way to generate hillock-like nanostructures on CaF2(111) ionic crystals by kinetic energy deposition upon Au-cluster irradiation. In the past, the formation of similar nanostructures has been observed for both slow highly charged ions and swift heavy ions. However, in these cases, potential energy deposition of highly charged ions or the electronic energy loss of fast heavy ions, respectively, first leads to strong electronic excitation of the target material before the excitation energy is transferred to the lattice by efficient electron-phonon coupling. We now show that the kinetic energy deposited by slow single Au-clusters directly in the lattice of CaF2(111) leads to the production of nano-hillocks very similar to those found with slow highly charged and swift heavy ions, with heights between 1 and 2 nm. Our results are in good agreement with previous cluster irradiation studies regarding energy deposition and hence nano-structuring of surfaces, and we present Au-cluster irradiation as novel tool to fine-tune nanostructure formation.
Synthesis and photocatalytic degradation of rhodamine B using ternary zeolite/WO3/Fe3O4 composite
Authors: Rubab Maham , Bhatti Ijaz Ahmad , Nadeem Nimra , Shah Syed Ali Raza , Yaseen Muhammad , Naz Muhammad Yasin , Zahid Muhammad
Published: May 2021

Demand for freshwater increases day by day as impurity increases due to the industrial, domestic and municipal waste in the water. Inappropriate disposal of coal fly ash (CFA) is not eco-friendly, therefore the need is to convert it into some beneficial material like zeolite. Zeolite-based composites with metal oxides show high cation interchange capacity, fast adsorption, and high efficiency for the removal of wastewater pollutants. In this research work, metal oxide along with zeolite (derived for CFA) was prepared. Metal oxide (WO3) and magnetite (Fe3O4) based zeolite composite was used adsorption enhanced photocatalytic degradation of rhodamine B dye. Ternary composite (zeolite/WO3/Fe3O4) was characterized using a scanning electron microscope, x-ray diffraction, Fourier transform infrared spectroscopy. The bandgap energy of composite was estimated using Tauc plot method from the data obtained after UV–visible spectroscopy. The behavior of composite under acidic and basic conditions was analyzed using pHpzc of the composite. Influencing parameters like pH, dye concentration, contact time, and catalyst dosage was optimized under ultraviolet irradiations (254 nm). The results show that maximum degradation was achieved with zeolite/WO3/Fe3O4 composite under optimized conditions of pH = 7, catalyst dosage = 10 mg/100 ml, RhB concentration 10 ppm, and time 60 min. The first-order kinetic model was best fitted to the experimental data. RSM was used as a statistical tool to analyze the data.