bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental aspects of technology and technical support of PVC production based on clustering of the economy
Authors: Kharlampenkov Evgeniy , Kudryashova Irina , Zakharova Natalia , Loginova Anastasiya
Published: June 2021

The production of polyvinyl chloride (PVC) is a very promising and dynamically growing segment of the chemical industry. In the article it’s considered new aspects of technical equipment of the PVC production enterprise from the point of view of reducing the environmental load on the environment. There are identified ways to reduce energy intensity and capital intensity of this production process due to the use of innovative technologies, in particular plasma-chemical pyrolysis of coke or methane contained in coke gas. The PVC production will require the development of cooperative ties between the coke chemical enterprise and chemical enterprises of the Kemerovo region on the basis of clustering of the regional economy. In the article, on the basis of data on similar enterprises, the cost of technological equipment was calculated, unit costs per unit of production and the cost of the project to create PVC production based on the raw materials of «KOKS» PJSC were determined. The use of the proposed technology will reduce the burden on the ecology of the region.
Digital Modernization of the Russian Mining Sector in Accordance with the National Technology Initiative and Mining 4.0
Authors: Dotsenko Elena , Ezdina Natalia , Breider Natalia , Khouri Samer
Published: June 2021

Currently, a new impetus for the innovative development of the Russian economy is associated with the formation and implementation of measures within the framework of the National Technology Initiative, aimed at the expansion of national high-tech companies into world markets. At the same time, there is a large-scale consumer of Industry 4.0 technologies in the domestic market – the extractive sector of the Russian industry, in need of technological support for innovative modernization. Today, the mining industry around the world is in a process of technological transformation, as digital and automated technologies are transforming traditional technologies for the extraction of energy and non-energy minerals. In the era of volatile global demand for raw materials, stricter safety and environmental requirements and dwindling profits, the mining industry must increase its investment attractiveness by radically increasing productivity as a result of the introduction of intelligent mining systems. Thus, new technological requirements of the Russian mining industry can be satisfied within the key areas of the National Technology Initiative. For this, it is important to unite the efforts of representatives of business, the scientific and educational community, the state, and international partners in the interests of the technological modernization of the mining complex as a factor of national economy development.
The Students’ Motivation in Studying and Mastering a Profession in Coal Region Universities
Authors: Resenchuk Anna , Tunyova Nina
Published: June 2021

This paper discusses the approach to teach professional vocabulary and motivation to study to mining students with the emphasis on career guidance work and online technologies which can help enhance learning activities. They may include web services or applications used for creating activities and engage students to learning environment. The paper deals with integration into the educational process such web-services as Learning Apps, H5P, Factile, aimed students to build and enlarge professional vocabulary necessary to read and analyze scientific articles, to operate it in future professional activity while communicating with foreign colleagues. The results of diagnostic tool (questionnaire) allow us to work with communicative, personal, behavioral and professional competence of the students. The article notes that high professional interest and acquired knowledge and skills will make the students able to work successfully in the mining industry sharing experience and cooperating with international partners. Kuzbass (Kemerovo region) is one of the largest coal deposits in the world, located in the south of Western Siberia. Region has significant experience in training compatriot specialists and international students in geology, mining industry, ecology and nature management. Future highly qualified specialists should not only master the production process, but also be able to share experience and communicate with foreign colleagues.
Competing Federal Universities as a Platform for Sustainable Development of Mineral Extracting Economy
Authors: Voloshin Andrey , Suslova Julia , Demchenko Svetlana , Batraeva Elina , Batraev Marcel , Khouri Samer
Published: June 2021

In the context of the transition of mineral extractive economies to sustainable development, the role of scientific and innovative support of this process is increasing. Universities are key components of this structural breakthrough. For the Russian economy, interaction and competition between federal universities are especially important, which, on the one hand, offer new technologies of "green" mining, and on the other, they form a high-tech breakthrough. The authors of the study have analyzed the competitiveness of Russian federal universities based on a developed methodology. This allows them to identify leaders and outsiders among these educational organizations and determine their strengths and weaknesses. The results allow the authors to determine the competitiveness of federal universities based on aggregated indicators that consider the influence of internal and external environment factors. The developed and tested methodology is based on the performance indicators of educational organizations, the "Project 5-100" indicators, and the indicators of international competitiveness.
Advantages and Disadvantages of Using Information Communication Technologies in the Process of Forming Language Competence in Global Mining Education
Authors: Chistyakova Galina , Bondareva Evgeniya , Demidenko Ksenia , Rolgayzer Anastasia
Published: June 2021

In connection with the COVID-19 pandemic, university education has undergone dramatic changes, resulting in a justified increase in the need for the development of distant learning. Today, information technology is an invaluable part of the learning process around the world. The purpose of this article is to analyze positive and negative aspects of applying information and communication technologies to the process of teaching foreign languages to students of mining specialties. The ways of solving the problems, identified in the discipline "Foreign language" in the course of the practical implementation of distance learning, are outlined. The possibilities of using such information tools as video lectures, video conferences, electronic coursebooks, computer testing are considered. Particular attention is devoted to the Moodle course management system as the most effective technology contributing to the formation of the language skills of future mining engineers. The authors come to the conclusion that each of the considered innovative educational technologies has a number of undeniable advantages, thus having a positive impact on both teachers and students. The recommendations developed by the authors provide a means for improving pedagogical design at the level of both individual teachers and universities.
Preservation of the Shor Language of the Small People of Kuzbass as a Component of Russian Coal Cluster Sustainable Development
Authors: Dubrovskaya Olga , Bondareva Evgeniya
Published: June 2021

The Shor are a small indigenous people of Western Siberia. In total, there are 13 thousand representatives of this nation in the world. The ethnos was formed in the 6-9 centuries. Kuzbass – the largest coal cluster in Russia – is a home for a significant part of the Shor population, being the indigenous minority of the region. The development of mining operations (mainly coal and iron ore mining) negatively affects the territory of the Shor people habitation. Therefore, the preservation of their cultural traditions, including the original language, is an important part of the sustainable development of the mining region Kuzbass. The suggested study is based on the Shor language material, which belongs to the Turkic branch of the Altai language family. The purpose of the study is to describe the synthetic type of complex sentences in the Shor language, which is designed to help preserve their culture in the system of sustainable development of Kuzbass.
The Risky Influence of Artificial Intelligence Technologies on the Foreign Language Proficiency of Eurasian Students in Mining
Authors: Islamov Roman
Published: June 2021

The article touches upon a topic of current importance, viz. the influence of the artificial intelligence (AI) found in some educational information and communication technologies (ICT) on the upcoming generations of graduates of higher education institutions. This is an issue of their prospective work in the industry (especially the mining one). This matter is considered for the students of mining fields of specialization in foreign language classes of the Kemerovo Region (a.k.a. Kuzbass) universities. The special group under consideration is the international students from Middle Asia, India, and China. The article aims to define the peculiarities of AI’s influence on an undergraduate via ICT in foreign language classes at the tertiary level. The article explains why some types of ICT may be considered as AI systems; how their inclusion into the educational process influences the cognitive changes of an undergraduate, and what role the level of trust plays in this. The scientific novelty is the consideration of the influence of ICT on the cognitive abilities of a student learning a foreign language through a prism of AI. In conclusion, the closer AI of ICT to the human activity working with a foreign language, the lower activation of the cognitive activity of a student is.
Analysis of Trends of the Sustainable Development Strategy of Coal Industry in Kuzbass
Authors: Dymova Irina , Formulevich Yanina , Karpova Olga , Lyamkin Igor
Published: June 2021

The article analyzes the trends of the strategy of sustainable development of coal industry in Kuzbass and the prospects for its development. The main problems connected with the coal enterprises operations are identified, possible ways of their solutions are presented within the framework of the adopted "Strategy for social-and-economic development of the region for the period up to 2035". Having analyzed the program under study, the proposals for its correction or addition in terms of improving the ecology of the region, social-and-economic development, preserving the natural landscape and biogeocenosis were made. The options for transporting coal and increasing the level of coal production technologies in underground mining were proposed. The article provides statistical data on coal mining for the period 2009-2020, and international experience of coal-mining countries. The authors consider the problems of export and transportation of coal, the impact of world prices on coal production. In addition, the authors of the article focus on the legal and legislative consolidation of the main conditions for control and regulation of the subsoil use in Kuzbass, make proposals for its effectiveness, in order to reduce social tension, environmental pollution, reduce the risk of earthquakes, and preserve coal resources for future generations.
Using Innovative Control in Distance Learning of Mining Students to Foreign Languages in the Context of Pandemic
Authors: Lebedintsev Sergey , Fedyanina Lyubov , Gustov Vyacheslav
Published: June 2021

This article presents innovative control methods used in the online foreign language learning of mining students of a technical university in forced conditions caused by the global pandemic which has been provoked by the coronavirus. The authors of this article substantiate the important role of intermediate control, give a detailed description of its functional tasks and note its intermediary mission by which feedback between a teacher and a student is created which is a necessary factor for the successful formation of language competence as an integral part of professional foreign-language communicative competence in distance learning. The authors of the article have developed a whole range of innovative items in the form of faceted testtables which are successfully used in foreign-language distance learning of mining students in the context of a pandemic.
Information Space for Sustainable Development and its Modern Transformation
Authors: Mudrova Svetlana , Lisitsyna Еkaterina , Rudenko Victoria , Galstyan Gagik
Published: June 2021

The article analyzes the backbone concepts of the spatial theory of sustainable development of modern countries – information space. The aim of the study is to substantiate the author's interpretation of the conceptual apparatus of spatial analysis, taking into account the principles of methodological institutionalism (comparative studies). In accordance with the purpose of the research, the following tasks are set and solved in the article: the essence of the information space in the system of sustainable development as a set of interactions of economic agents affecting the environment is disclosed; the attributive properties of the information space are formulated; the directions of its transformation under the influence of sustainable development processes are determined; the hypothesis about the transformation of the information space into information and communication under the influence of digitalization processes is formulated. It is concluded that the enrichment of the conceptual apparatus of the theory of spatial economics is a necessary prerequisite for the development of tools for implementing the sustainable development strategy in the digital and spatial dimensions.
Strategizing of Regional Sustainable Development: Conceptual Provisions and Modern Tools
Authors: Mudrova Svetlana , Burdenko Elena , Galstyan Gagik
Published: June 2021

The article substantiates provisions aimed at improving the tools for implementing the strategy of sustainable spatial development of the Russian Federation, taking into account the processes of systemic digital transformation of the economy. The aim of the study is to substantiate a new methodological approach to the interpretation of the patterns of sustainable regional development, which considers the spatial and environmental factors as endogenous sources of sustainable growth. To achieve this goal, the stages of development of ideas about the regional economy and regional development were determined, the content of the spatial approach to the interpretation of economic phenomena and processes was clarified, recommendations were formulated aimed at improving the toolkit of regional policy, taking into account the structuredness and multipolarity of the Russian economic, environmental and information space. The result of the study is the conclusion about the heterogeneity of the space of Russian regions and the need to take into account environmental space quality indicators when developing program measures for sustainable development, as well as in assessing their effectiveness.
Labor Market as a Factor of Sustainable Development of the Coal Mining Region
Authors: Ozderbiyeva Zhanna , Shershneva Olga
Published: June 2021

The article examines the labor market as a factor of sustainable development. It substantiates that sustainable development of the coal mining region is possible if there is an effective labor market, which is characterized by the correlation of the demand for labor and its supply, decent work and the level of wages relevant to the needs of the able-bodied population. This places demands on the quality of the workforce and the provision of efficient employment. The authors revealed the relationship between the sustainable development of the regional economy and the labor market.
Financial Risks and their Management in the Mining Industry
Authors: Frolova Viktoriia , Glinkina Olga , Shpilkina Tatyana
Published: June 2021

The authors investigated the issues of assessing financial risks in the mining industry, studied the problems of hedging risks in conditions of high uncertainty when a company enters foreign markets. The importance of the SPIC document was determined as a form of interaction between enterprises and the state, which allows more actively investing in the mining industry, while reducing risks for investors. The article outlines the issues of digitalization that allow managing financial risks, based on biogeography in order to optimize the rules for mining, as well as a system of classification rules (CRI) for a qualitative and quantitative approach in predicting bankruptcy and analyzing credit risk.
Reproductive Approach to the Implementation of the Concept of Regional Sustainable Development
Authors: Demchenko Olga , Melnikova Tatyana , Demtschenko Sveta , Schmitt Margarita
Published: June 2021

The article examines the problems of sustainable development of the regional economy from the position of the reproductive approach. The expediency of using the reproductive approach as a methodological tool for studying the sustainability and efficiency of economic systems, both at the level of the region and the country as a whole, is noted. Sustainable development of the economic system involves the consideration of reproduction processes from the social, economic and environmental points of view, which makes it possible to assess the sustainability of the processes of production, distribution, exchange and consumption. A system of indicators for assessing the economic, social and environmental sustainability of the development of the region is proposed, based on the sustainability of reproduction processes.
A model for the time dependent vehicle routing problem with time windows under traffic conditions with intelligent travel times
Authors: Khanchehzarrin Saeed , Shahmizad Maral , Mahdavi Iraj , Mahdavi-Amiri Nezam , Ghasemi Peiman
Published: June 2021

A new mixed-integer nonlinear programming model is presented for the time-dependent vehicle routing problem with time windows and intelligent travel times. The aim is to minimize fixed and variable costs, with the assumption that the travel time between any two nodes depends on traffic conditions and is considered to be a function of vehicle departure time. Depending on working hours, the route between any two nodes has a unique traffic parameter. We consider each working day to be divided into several equal and large intervals, termed as a time interval of traffic. Here, allowing for long distances between some of the nodes, travel time may take more than one time interval of traffic, resulting in resetting the time interval of traffic at the start of each large interval. This repetition of time interval of traffics has been used in modeling and calculating travel time. A tabu search optimization algorithm is devised for solving large problems. Also, after linearization, a number of random instances are generated and solved by the CPLEX solver of GAMS to assess the effectiveness of our proposed algorithm. Results indicate that the initial travel time is estimated appropriately and updated properly in accordance with to the repeating traffic conditions.
Neuroaxiale Gabe von Morphin nach Sectio caesarea: ein Update
Authors: Oji-Zurmeyer Julia , Ortner Clemens , Klein Klaus Ulrich , Putz Günther , Jochberger Stefan
Published: June 2021

Für die Behandlung von Schmerzen nach Sectio caesarea (Wundschmerz, Nachwehen) stellt die neuroaxiale Morphingabe in Kombination mit peripher wirkenden Analgetika im angloamerikanischen Raum den Goldstandard dar. Damit kann eine langanhaltende Analgesie (bis zu 24 h) erreicht werden. Dieser Beitrag stellt den aktuellen Wissensstand zu diesem Thema dar und beschreibt die gegenwärtigen Empfehlungen.
Zwanzig Jahre Levosimendan
Authors: Häberle Helene A.
Published: June 2021

Vasopressoren kommen besonders in kritischen, nicht selten lebensbedrohlichen Situationen der Anästhesie, Notfall- und Intensivmedizin zum Einsatz. Die Wahl der geeigneten Substanz sowie die Erkennung und Beherrschung möglicher Nebenwirkungen sind von großer Bedeutung. Im folgenden Beitrag sollen daher die klinisch wichtigsten Substanzen vorgestellt und deren pharmakologische Charakteristika beleuchtet werden.
Outcome of TRAP Sequence Treated in the First Trimester – A Ten-Year Single-Center Experience
Authors: Weber Eva Christin , Recker Florian , Gottschalk Ingo , Strizek Brigitte , Geipel Annegret , Gembruch Ulrich , Berg Christoph
Published: June 2021

Purpose To evaluate the outcome of first trimester intervention by intrafetal laser (IFL) in pregnancies complicated by twin reversed arterial perfusion (TRAP).

Materials and Methods For a 10-year study period, all patients with TRAP diagnosed < 14.0 weeks of gestation were retrospectively analyzed for intrauterine course and outcome. Monoamniotic pregnancies were excluded. Patients were offered either intervention by IFL in the first trimester, expectant management, or termination of pregnancy (TOP). Adverse outcome was defined as either intrauterine death (IUD), neonatal death, or preterm birth.

Results In 45 cases TRAP was diagnosed. 17 monoamniotics were excluded. The cohort was divided into two groups according to management. Group A: 24 cases underwent IFL and group B: 4 cases were managed expectantly. No patient opted for TOP. In group A, 70.8 % of pump twins were born alive, including one preterm delivery, and 29.2 % died within four days after the intervention. All 4 expectantly managed cases in group B had an adverse outcome (1 preterm delivery, 3 IUDs < 15.0 weeks). There were no neonatal deaths. In cases treated by IFL, a comparison of survivors and non-survivors identified no significant differences in gestational age at IFL or any of the assessed biometrical and functional parameters. There was a trend towards better outcome in the second half of the study period.

Conclusion IFL in first trimester TRAP sequence is technically feasible but is associated with significant mortality, albeit less than previously reported. No risk stratification is possible using the investigated parameters. However, there seems to be a learning curve.
Arthroscopic Oblique Partial Ulnar Styloid Resection for Ulnar Styloid Impaction Syndrome
Authors: Pääkkönen Markus
Published: June 2021

Background Open or arthroscopic partial resection of the elongated ulnar styloid is the surgical treatment of choice for ulnar styloid impaction syndrome.

Case Description A patient with a severely elongated processus styloideus ulnae (PSU) with a chronic impaction of the distal-radial margin against the triquetrum suffered a traumatic triangular fibrocartilage complex (TFCC) Palmer 1B rupture and DRUJ instability. The length of the PSU was 9 mm. After failed conservative treatment, a partial oblique arthroscopic resection of the PSU and simultaneous TFCC reinsertion were performed with uneventful recovery.

Literature Review Arthroscopic resection has emerged as an alternative to the traditional open PSU resection for the treatment of styloid impaction syndrome. A transverse resection is described as the treatment of choice. Regarding the extent of resection subtotal ligament sparing resection or resection to the lower margin have been suggested.

Clinical Relevance Surgical planning of PSU resection should take into consideration the anatomy of the impingement. The extent of resection should be planned individually, and sometimes an oblique resection may be the preferred option.
Robotic Arm-Assisted versus Manual Total Knee Arthroplasty: A Propensity Score-Matched Analysis
Authors: Samuel Linsen T. , Karnuta Jaret M. , Banerjee Aditya , Briskin Isaac , Cantrell William A. , George Joseph W. , Higuera-Rueda Carlos A. , Kamath Atul F. , Khlopas Anton , Klika Alison , Krebs Viktor E. , Mesko Nathan W. , Mont Michael A. , Murray Trevor G. , Piuzzi Nicolas S. , Shah Paras , Stearns Kim , Sultan Assem A. , Molloy Robert M.
Published: June 2021

The purpose of this study was to compare (1) operative time, (2) in-hospital pain scores, (3) opioid medication use, (4) length of stay (LOS), (5) discharge disposition at 90-day postoperative, (6) range of motion (ROM), (7) number of physical therapy (PT) visits, (8) emergency department (ED) visits, (9) readmissions, (10) reoperations, (11) complications, and (12) 1-year patient-reported outcome measures (PROMs) in propensity matched patient cohorts who underwent robotic arm-assisted (RA) versus manual total knee arthroplasty (TKA). Using a prospectively collected institutional database, patients who underwent RA- and manual TKA were the nearest neighbor propensity score matched 3:1 (255 manual TKA:85 RA-TKA), accounting for various preoperative characteristics. Data were compared using analysis of variance (ANOVA), Kruskal–Wallis, Pearson's Chi-squared, and Fisher's exact tests, when appropriate. Postoperative pain scores, opioid use, ED visits, readmissions, and 1-year PROMs were similar between the cohorts. Manual TKA patients achieved higher maximum flexion ROM (120.3 ± 9.9 versus 117.8 ± 10.2, p = 0.043) with no statistical differences in other ROM parameters. Manual TKA had shorter operative time (105 vs.113 minutes, p < 0.001), and fewer PT visits (median [interquartile range] = 10.0 [8.0–13.0] vs. 11.5 [9.5–15.5] visits, p = 0.014). RA-TKA had shorter LOS (0.48 ± 0.59 vs.1.2 ± 0.59 days, p < 0.001) and higher proportion of home discharges (p < 0.001). RA-TKA and manual TKA had similar postoperative complications and 1-year PROMs. Although RA-TKA patients had longer operative times, they had shorter LOS and higher propensity for home discharge. In an era of value-based care models and the steady shift to outpatient TKA, these trends need to be explored further. Long-term and randomized controlled studies may help determine potential added value of RA-TKA versus manual TKA. This study reflects level of evidence III.
During Arthroscopic Repair of Medial Meniscal Tears: Do Not Be Afraid to Perform “Pie Crust” Technique
Authors: Arıcan Gökhun , Ercan Niyazi , Atmaca Emre , İltar Serkan , Alemdaroğlu Kadir B.
Published: June 2021

In the absence of effective long-term repair of meniscal injuries, damage to the knee may lead to the development of osteoarthritis. Recent reports have recommended meniscal repair to be undertaken in all cases of meniscal tears. However, the most common complication encountered during repair of the medial meniscus is iatrogenic cartilage and meniscal injury due to its unclear visualization. The aim of this study is to evaluate the long-term clinical and radiological results of the pie-crust (PC) technique performed during the repair of medial meniscal tears. This retrospective study included 86 patients who underwent arthroscopic medial meniscus repair. PC technique was performed if the medial joint width was less than 5 mm. The patient population was divided into two groups as who underwent meniscus repair with PC technique (PC + repair group) or not (repair group). All patients were evaluated clinically (Kujala score, International Knee Documentation Committee (IKDC) subjective score, Lysholm score, and Tegner activity score) and radiologically (medial joint width and valgus laxity angle). When the medial joint width measurements before the PC technique and at the postoperative first and sixth months were compared, it was found to be statistically significant (p < 0.05). However, there was no significant difference between the preoperative and 12-month postoperative joint width measurements (p > 0.05). At the 12-month follow-up, no statistically significant difference was determined for the valgus laxity angle in the PC group compared with preoperative values (p > 0.05). The follow-up Kujala score, IKDC subjective score, Lysholm score, and Tegner activity score were similar between the groups. The clinical scores in both groups were determined to have statistically significant increase at 12-month postoperatively compared with the preoperative values (p < 0.05). The results of this study showed that performing the PC technique prior to medial meniscal tear repair increase the medial joint visualization safely and effectively without permanent valgus laxity.
Concomitant Partial Achilles Tendon Rupture and Lateral Luxation of the Superficial Digital Flexor Muscle Tendon in a Dog
Authors: Dosseray Hélène , Deroy-Bordenave Claire
Published: June 2021

The aim of this study was to report a posttraumatic partial Achilles tendon (AT) rupture associated with lateral luxation of the superficial digital flexor tendon (SDFT) in a Whippet. This article is a brief communication. A Whippet was presented with posttraumatic plantigrade stance and non-load-bearing lameness of the right pelvic limb. The objective findings consisted in partial AT rupture and SDFT lateral luxation. Surgical treatment ensued: tenorrhaphy of the torn tendons and calcaneo-tibial screw insertion for tarsal immobilization, followed by suturing of the SDFT retinaculum. A casting bandage was employed for additional immobilization. Nonetheless, a bandage complication prompted the premature removal of the fixation screw and casting wrap. Complete functional recovery was achieved by the 20th postoperative week. The simultaneous occurrence of SDFT luxation and partial AT tear has not been reported in the literature before. The long-term postoperative functional outcome was highly satisfactory.
On the energy spectrum and thermodynamics of decorated quasi-one-dimensional magnetic systems with uniaxial anisotropy
Authors: Ezerskaya E. V.
Published: June 2021

This paper is devoted to the study of thermodynamics of the quasi-1D spin models with Ising interaction between complex unit cells by transfer-matrix method. The field and the temperature dependences of the main thermodynamic characteristics have been investigated. It is shown that the field dependence of the magnetization at low temperatures for the models of “comb” and “decorated comb,” and decorated triangles structures have an intermediate magnetization plateau in case of antiferromagnetic Ising interactions. The temperature dependence of the heat capacity may have several maxima in zero magnetic field. For the chain model of triangles decorated by Ising spins through the one vertex and for the “double decorated comb” some kind of the pseudo-phase transitions in the critical magnetic field is found.
Quantum magnetoresistance in Si  whiskers
Authors: Druzhinin A. , Ostrovskii I. , Khoverko Yu. , Liakh-Kaguy N.
Published: June 2021

It was studied the electrical magnetoresistance of nickel-and boron-doped filamentary silicon crystals in which a metal-insulator transition is observed. A giant magnetoresistance reaches up to 280% in the Si whiskers with doping concentration of boron р300K = 5⋅1018 cm−3 in the magnetic fields with induction up to 14 T at temperature 4.2 K. Peculiarities of magnetoresistance at low temperatures were shown to be caused by “core-shell” structure of crystals. A giant magnetoresistance nature was considered within quantum magnetoresistance model. The analysis was performed to determine the critical field of transition from classical parabolic magnetoresistance to quantum magnetoresistance, realized in the near-surface region of the crystal. The silicon whiskers were used for design of magnetic field sensors.
A nanodusty plasma experiment to create extended dust clouds using reactive argon acetylene plasmas
Authors: Chutia Bidyut , Deka T. , Bailung Y. , Sharma S. K. , Bailung H.
Published: June 2021

A large volume 3D dust cloud containing in situ grown nanometer-sized particles is produced in a newly developed versatile table-top experimental device. Carbonaceous nanoparticles having almost uniform size throughout the dust cloud are grown using capacitively coupled rf discharge in Ar–C2H2 gas mixture with a low precursor gas flow rate (∼2  sccm) and minimal rf power (∼1 W). The vertical and radial extensions of the dust cloud are 40 cm and 5 cm, respectively. The pure Ar plasma in the setup is characterized by measuring the discharge parameters as well as plasma parameters under different discharge conditions. The average particle size and its temporal growth profile are determined by analyzing the scanning electron microscope images of the particles. The dust density measured using the laser extinction method is found to be of the order of 1016–1012 m−3 for the discharge duration of 2–10 min. A spontaneous dust density wave is also observed in the dust cloud.
Data-driven inference of high-accuracy isostable-based dynamical models in response to external inputs
Authors: Wilson Dan
Published: June 2021

Isostable reduction is a powerful technique that can be used to characterize behaviors of nonlinear dynamical systems using a basis of slowly decaying eigenfunctions of the Koopman operator. When the underlying dynamical equations are known, previously developed numerical techniques allow for high-order accuracy computation of isostable reduced models. However, in situations where the dynamical equations are unknown, few general techniques are available that provide reliable estimates of the isostable reduced equations, especially in applications where large magnitude inputs are considered. In this work, a purely data-driven inference strategy yielding high-accuracy isostable reduced models is developed for dynamical systems with a fixed point attractor. By analyzing steady-state outputs of nonlinear systems in response to sinusoidal forcing, both isostable response functions and isostable-to-output relationships can be estimated to arbitrary accuracy in an expansion performed in the isostable coordinates. Detailed examples are considered for a population of synaptically coupled neurons and for the one-dimensional Burgers’ equation. While linear estimates of the isostable response functions are sufficient to characterize the dynamical behavior when small magnitude inputs are considered, the high-accuracy reduced order model inference strategy proposed here is essential when considering large magnitude inputs.
Laminar to turbulent transition in a finite length square duct subjected to inlet disturbance
Authors: Khan Hamid Hassan , Anwer Syed Fahad , Hasan Nadeem , Sanghi Sanjeev
Published: June 2021

Laminar to turbulent flow transition in a finite length square duct has been carried out by imposing novel spatiotemporal finite amplitude inlet disturbance on the laminar flow. The present direct numerical simulation study demonstrates the effect of inlet disturbance on laminar to turbulent transition. A laminar flow in a finite length square duct is considered at bulk Reynolds number Re = 2260 and Re = 1540, to which a novel spatiotemporal disturbance is introduced through a narrow banded region at the inlet of the square duct. The puff (transition) and slug (turbulent) flow dynamics indicate the laminar to turbulent transition in a square duct. Disturbance introduced at Re = 2260 laminar flow propagates downstream, giving puff and slug flow phenomena similar to pipe flows. However, at Re = 1540, inlet disturbance shows only a puff-like structure. The four vortex mean secondary flow is observed in a puff region, while the conventional eight vortex is observed in the slug region. The coherent structures of the transition (puff) flow show the presence of dual-type hairpin structures. The turbulent kinetic energy spectrum indicates conventional −5/3 spectra for slug flow and −2 energy spectra for puff flow. Thus, in this paper, it is shown that the puff and slug characteristics of laminar to turbulent transition in a square duct are similar to that of a circular duct. It is also shown that the novel inlet disturbance through a narrow banded region captures the dynamics of laminar to turbulent transition in a square duct.
Thermal conductivity measurements of sub-surface buried substrates by steady-state thermoreflectance
Authors: Hoque Md Shafkat Bin , Koh Yee Rui , Aryana Kiumars , Hoglund Eric R. , Braun Jeffrey L. , Olson David H. , Gaskins John T. , Ahmad Habib , Elahi Mirza Mohammad Mahbube , Hite Jennifer K. , Leseman Zayd C. , Doolittle W. Alan , Hopkins Patrick E.
Published: June 2021

Measuring the thermal conductivity of sub-surface buried substrates is of significant practical interests. However, this remains challenging with traditional pump–probe spectroscopies due to their limited thermal penetration depths. Here, we experimentally and numerically investigate the TPD of the recently developed optical pump–probe technique steady-state thermoreflectance (SSTR) and explore its capability for measuring the thermal properties of buried substrates. The conventional definition of the TPD (i.e., the depth at which temperature drops to 1/e value of the maximum surface temperature) does not truly represent the upper limit of how far beneath the surface SSTR can probe. For estimating the uncertainty of SSTR measurements of a buried substrate a priori, sensitivity calculations provide the best means. Thus, detailed sensitivity calculations are provided to guide future measurements. Due to the steady-state nature of SSTR, it can measure the thermal conductivity of buried substrates that are traditionally challenging by transient pump–probe techniques, exemplified by measuring three control samples. We also discuss the required criteria for SSTR to isolate the thermal properties of a buried film. Our study establishes SSTR as a suitable technique for thermal characterizations of sub-surface buried substrates in typical device geometries.
Cryoplasma-mediated fabrication of Au-TiO2 composite film using freezing ice front templated structures
Authors: Sakakibara Noritaka , Iwase Kengo , Koike Takeru , Ito Tsuyohito , Terashima Kazuo
Published: June 2021

Ice-templating is a powerful technique that exploits self-organized ice structures formed during the freezing of colloidal suspensions as templates to fabricate microstructured materials. However, the active introduction of reactivity to the ice-templating process remains limited. In this study, a Au-TiO2 composite film composed of gold and titanium oxide (TiO2) was fabricated on a frozen aqueous colloidal suspension, using cryoplasma to introduce reactive species to the frozen suspension. Auric ions and TiO2 nanoparticles were segregated on the ice body by one-directional freezing of the aqueous colloidal suspension from the lower side. Meanwhile, a cryoplasma, in which the gas temperature was controlled to be lower than the melting point of water, was irradiated onto the frozen aqueous colloidal suspension to facilitate the chemical reduction of gold ions and the formation of gold bridges between TiO2 nanoparticles. The face of the fabricated Au-TiO2 composite film that had been adjacent to the ice structure during its formation was shown to possess both greater roughness and higher photocatalytic activity for methylene blue degradation when the aqueous colloidal suspension was frozen at a higher temperature during the fabrication of the composite film. The temperature dependence of the roughness and photocatalytic activity indicates a potential of the combination of cryoplasma irradiation and ice-templating processes for structure-controlled fabrication of composite film materials, suggesting that alterations in the structure of the freezing ice front that occur with changes in temperature can be harnessed.
Enhancement of A′-site Mn3+ spin ordering by B-site Mn4+ substitution in quadruple perovskite PbMn3Cr3MnO12
Authors: Liu Guangxiu , Zhou Long , Zhou Bowen , Ye Xubin , Lu Dabiao , Shen Xudong , Qin Shijun , Hu Zhiwei , Chin Yi-Ying , Lin Hong-Ji , Chen Chien-Te , Yu Xiaohui , Long Youwen
Published: June 2021

An A-site ordered but B-site disordered quadruple perovskite oxide PbMn3Cr3MnO12 was synthesized by high-pressure and high-temperature methods. The compound crystallizes in space group Im-3 with the charge distribution of Pb2+Mn3+3Cr3+3Mn4+O12. Three antiferromagnetic phase transitions are found to occur at TN1 ≈ 155, TN2 ≈ 81, and TN3 ≈ 74 K, respectively, due to the complex B-site and A′-B intersite spin interactions. Compared with the isostructural LaMn3Cr4O12 with negligible A′-B intersite spin coupling, the substitution of Mn4+, which has identical electronic configuration to that of Cr3+ (t2g3), into the B site can introduce A′-B intersite spin interactions. As a result, the A′-site spin-related ordering temperature increases significantly, while the B-site one remains little changed in the current PbMn3Cr3MnO12. This work opens up a way to enhance the A′-site spin ordering temperature in quadruple perovskite oxides.
Demonstration of high efficiency cascaded blue and green micro-light-emitting diodes with independent junction control
Authors: Li Panpan , Li Hongjian , Yao Yifan , Zhang Haojun , Lynsky Cheyenne , Qwah Kai Shek , Speck James S. , Nakamura Shuji , DenBaars Steven P.
Published: June 2021

We demonstrate efficient cascaded blue/green micro-size light-emitting diodes (μLEDs) with independent junction control. The cascaded μLEDs, consisted of blue μLEDs, a tunnel junction, and green μLEDs, were fully grown by metalorganic chemical vapor deposition. Blue, green, and blue/green emissions can be independently controlled in the same device. The blue μLEDs (60 × 60 μm2) and green μLEDs (40 × 40 μm2) exhibit a forward voltage of 4.1 and 3.1 V at 20 A/cm2 and a high peak external quantum efficiency of 42% and 14%, respectively. This demonstration paves the way for monolithic integration of full color cascaded μLEDs.
Effect of viscous shearing stresses on optimal material designs for flow of fluids through porous media
Authors: Phatak Tejasree , Nakshatrala Kalyana B.
Published: June 2021

Topology optimization offers optimal material layouts, enabling automation in the design of devices. Given the recent advances in computer technology and additive manufacturing, topology optimization is increasingly being used to design complex porous structures, for example, microfluidic devices. For the flow of fluids in such miniature-sized porous structures, viscous shearing stresses will be significant. However, the Darcy model—the most popular mathematical model describing the flow of a single-phase incompressible fluid in rigid porous media—neglects the internal friction arising from viscous shearing stresses. We, therefore, develop a material design framework under the topology optimization based on the Darcy–Brinkman model—a mathematical model for the flow of fluids through porous media that accounts for internal friction besides the drag considered in the Darcy model. The proposed framework uses the total rate of mechanical dissipation—a physical quantity—for the objective function. To understand the effect of viscous shearing stresses on the design, we compare the optimal material layouts provided by the Darcy and Darcy–Brinkman models under topology optimization. In particular, we show, using analytical solutions corroborated by numerical simulations, that the optimal material layouts are alike for the class of problems exhibiting axisymmetry, for which viscous shearing stresses vanish. These analytical solutions will be valuable to check the veracity of numerical simulators. For those problems with dominant viscous shearing stresses (e.g., flow in a backward-facing step domain), we show, using numerical solutions, the optimal material layouts under the Darcy and Darcy–Brinkman models are very different. Also, the associated solution fields (i.e., velocity and pressure) are qualitatively different under their respective optimal layouts for these two models.
Efficient generation of UV-enhanced intense supercontinuum in solids: Toward sub-cycle transient
Authors: Su Yabei , Fang Shaobo , Gao Yitan , Zhao Kun , Chang Guoqing , Wei Zhiyi
Published: June 2021

Ultrabroadband generation of white-light continuum spanning from ultraviolet to near-infrared (375–920 nm) is demonstrated by using induced-phase modulation between two-color femtosecond pulses in multiple thin plates. The fundamental wave and its second-harmonic wave from one Ti:sapphire chirped-pulse amplifier are injected into nine 100 μm-thick fused silica plates. When the two pulses are temporally and spatially optimized in the plates, an intense supercontinuum is efficiently achieved by utilizing self-phase modulation and self-steepening together with induced-phase modulation. As a result, using 1 kHz, 1 mJ, and 35 fs pulses at 800 nm as the pump, we demonstrate the generation of 0.6 mJ white-light pulses with an ultra-broad bandwidth supporting 1.6 fs transform-limited pulses corresponding to 0.6-optical-cycle at a central wavelength of 750 nm. Analysis of the calculated spectrum fits the experimental results well, and the pulse is quasi-linearly chirped and compressible. The resulting intense robust supercontinuum could be a promising light source for an ever greater degree of tailored optical waveform coherent control in new parameter spaces.
An inversion of contact angle hysteresis when a liquid drop slides up on an inclined plane under the spark discharge action
Authors: Dubinov Alexander E. , Iskhakova Djamilya N. , Lyubimtseva Valeria A.
Published: June 2021

A new physical effect, consisting in the crossover of values and inversion of the dynamic contact angles' hysteresis branches, when a glycerin drop and a water drop slide up a smooth inclined steel plane under the action of nanosecond spark discharges' periodic sequence, was experimentally recorded.
18.8 Gbps real-time quantum random number generator with a photonic integrated chip
Authors: Bai Bing , Huang Jianyao , Qiao Guan-Ru , Nie You-Qi , Tang Weijie , Chu Tao , Zhang Jun , Pan Jian-Wei
Published: June 2021

Quantum random number generators (QRNGs) can produce true random numbers. Yet, the two most important QRNG parameters highly desired for practical applications, i.e., speed and size, have to be compromised during implementations. Here, we present the fastest and miniaturized QRNG with a record real-time output rate as high as 18.8 Gbps by combining a photonic integrated chip and the technology of optimized randomness extraction. We assemble the photonic integrated circuit designed for vacuum state QRNG implementation, an InGaAs homodyne detector, and a high-bandwidth transimpedance amplifier into a single chip using hybrid packaging, which exhibits the excellent characteristics of integration and high-frequency response. With a sample rate of 2.5 GSa/s in a 10-bit analog-to-digital converter and subsequent paralleled postprocessing in a field programmable gate array, the QRNG outputs ultrafast random bitstreams via a fiber optic transceiver, whose real-time speed is validated in a personal computer.