bluuebunny/crossref_metadata_2025 huggingface dataset:
Methodology for creating a residential three-rayed space-planning structure
Authors: Nureyev Tagir , Popov Anton
Published: June 2021

Problem statement. The purpose of this study is to create a methodology for designing a residential three-rayed space-planning structure for small and medium-rise buildings. The methodology was created for the central and southern insolation zones of Russia in the conditions of sanitary standards of 2017. The methodology is applicable in countries located in both hemispheres of our planet with mirrored conditions of the Russian insolation standards.

Results. A methodology has been developed that creates many types of «daughter» residential sections based on a single «T-shaped» three-rayed residential section, which is called the «maternal». The applied result of the research was of 27 planimetric methods of architectural combinatorics and kinetics, as well as two patents. The presented methods are implemented in brick structures during the reconstruction of the residential quarter No. 75 in the historical center of the Russian city of Menzelinsk in the Republic of Tatarstan.

Conclusions. The significance of the results obtained for architecture lies in energy-efficient design, expressed in a reduction design time and an increase the types of «daughter» residential sections. The methodology was created for the future computer program for the design of multi-rayed structures of residential buildings of various storeys.
Formation of the actual typology of urban multi-apartment dwelling based on the principles of minimalism and autonomy of residential complexes
Authors: Zabruskova Marina , Mukhyanova Leysan , Saifutdinova Adelya
Published: June 2021

This article examines the ways of forming the current typology of an urban multi-apartment dwelling based on the principles of minimalism and autonomy. The purpose of this study is to identify in the design of residential buildings that meet the principles of minimalism and autonomy. The main result of the study is the analysis of domestic and foreign experience in the design of multi-apartment urban housing and residential environment, taking into account the principles of minimalism and autonomy. The significance of the results obtained for design practice lies in expanding the range and possibilities of forming new solutions for multiapartment urban economy, taking into account all factors.
Formation of a comfortable transport infrastructure for cyclist traffic in the tourist area of Kazan
Authors: Ibragimova Aniia , Petropavlovskikh Olga
Published: June 2021

This article examines the issue of cycling in Russian cities on the example of the city of Kazan. The authors come to the conclusion that the existing bicycle zones in Kazan aren’t connected to each other and don’t intersect complex transport hubs with high traffic intensity, therefore, cycling around the city isn’t safe and comfortable. As a solution to this problem, the idea of a new combined overpass, combining a pedestrian and roadway for cyclists, is presented. In addition, it’s proposed to develop the street and road network of the city of Kazan, through the construction of new bicycle paths. The combined overpass will allow for a more rational redirection of the city's traffic flows, ensure the safety of high-speed traffic and create comfortable conditions for the city's population. The construction of a bicycle path will reduce the total traffic load on the city's roads, and ensure safe movement for citizens in the central part of the city. Thus, the need to introduce and develop bicycling in our city, which entails planning not only bicycle paths, but also the construction of other transport infrastructure facilities for comfortable crossing of transport hubs with high traffic intensity by cyclists, seems obvious.
Pavement wear process and abrasive wear resistance of asphalt concrete
Authors: Gayfutdinov Rustem , Bajmukhametov Gadel , Hafizov Eduard
Published: June 2021

The aim of the article is an improvement of abrasion resistance of materials of road pavements and giving practical recommendations during the pavement designing to the construction organizations. The Prall Test method was used to identify the factors influencing the wear resistance of asphalt concrete. Studied mixtures and materials are typical for the highway construction in the Russian Federation and the Republic of Tatarstan. The influence of such factors as the type of mix, the size of the aggregate, the type of binder and the quality of the aggregate was studied. The study shows that the increase of the wear resistance and coarseness of the aggregate when using a polymer-modified binder and the reduction of the content of air voids increase the wear resistance of asphalt concrete mixtures.
Acceptable water flow rate in sandy channels
Authors: Latipov Shakhboz , Sagdiyev Jasur , Eshev Sobir , Kholmamatov Islom , Rayimova and Iroda
Published: June 2021

A comparison of the values obtained with the experimental data on noneroding velocity in the article shows that the soil erosion in the experiments took place much earlier because our experiments were carried out in trapezoidal channels, based on experiments in wide rectangular channels.
Stress state of hinged supported thin-wall elastic structures
Authors: Kharasova Lilya , Timergaliev Samat
Published: June 2021

The paper studies the stress-strain state of flat elastic isotropic thin-walled shell structures in the framework of the S. P. Timoshenko shear model with pivotally supported edges. The stress-strain state of shell structures is described by a system of five second-order nonlinear partial differential equations under given static boundary conditions with respect to generalized displacements. The system of equations under study is linear in terms of tangential displacements, rotation angles, and nonlinear in terms of normal displacement. To find a solution to the system that satisfies the given static boundary conditions, integral representations for generalized displacements containing arbitrary holomorphic functions are used. Finding holomorphic functions is one of the main and difficult points in the proposed study. The integral representations constructed in this way allow us to reduce the original problem to a single nonlinear operator equation with respect to the deflection, the solvability of which is established using the principle of compressed maps.
Strength of thin-walled elastic building structures
Authors: Kharasova Lilya
Published: June 2021

The existence theorem is proved within the framework of the shear model by S.P. Timoshenko. The stress-strain state of elastic inhomogeneous isotropic shallow thin-walled shell constructions is studied. The stress-strain state of shell constructions is described by a system of the five equilibrium equations and by the five static boundary conditions with respect to generalized displacements. The aim of the work is to find generalized displacements from a system of equilibrium equations that satisfy given static boundary conditions. The research is based on integral representations for generalized displacements containing arbitrary holomorphic functions. Holomorphic functions are found so that the generalized displacements should satisfy five static boundary conditions. The integral representations constructed this way allow to obtain a nonlinear operator equation. The solvability of the nonlinear equation is established with the use of contraction mappings principle.
Improving energy efficiency of rental housing
Authors: Shagiakhmetova Elvira , Burkeev Danil , Fedorova Svetlana , Shaikhutdinova Diana
Published: June 2021

Modern cities development is a conscious distribution of priorities. The ecology and resource conservation problems are becoming more and more relevant, and when the city's housing stock is managed, it is necessary to reduce the negative impact on the environment. The aim of the study is to provide an economic feasibility for the construction and the energy-efficient apartment building operation that can serve the needs of current and future generations, and also reduce the carbon footprint through sustainable consumption of electricity and water in domestic buildings. The studying object is an apartment building, in which the introduction of energy-efficient systems is proposed: rainwater harvesting, solar electric plant. During the calculations the questionnaire method, the retrospective indicators of mathematical analysis, the net current value (NPV) method, and the discounted payback period (DPP) method were used. The calculated results showed the effectiveness of the rental housing operation in Kazan (Russia). The payback period will continue for 8.27 years. The practical implementation of the results opens up opportunities for solving the problem of saving natural resources and reducing the carbon footprint of our cities.
Development of stress resistance of students of engineering universities during examination session by means of physical education
Authors: Khairullin Rafael , Kalimullina Olga , Salnicova Olga , Bachenina Elena , Ilin Sergei
Published: June 2021

The article deals with the problem of stressful situations in learning activities and development of a person’s stress resistance. The article investigates the conditions of stress resistance development of students by means of physical culture. In this aspect physical culture is considered as an integral quality of personality, as the condition and the premise of effective educational and professional activity, as the generalized indicator of professional culture of the future specialist and as the purpose of self-development and self-improvement.
The role of entrepreneur cooperation in the implementation of the sustainable development goals
Authors: Starodubova Anna , Iskhakova Dinara , Misbakhova Chulpan
Published: June 2021

The authors proposed a method for evaluating the level of cooperation among associations for sustainable development and their participants. The indicators of the structure, of the scale and the diversification of cooperation have been selected by expert method. As a result, the method classifies participants, including entrepreneurs, by level of cooperation. Researchers have proposed classes of participants in cooperation for sustainable development. This classification is based on the grouping methods and calculation of the interval. If the participant had higher class, this means the participant had the closer links in the cooperation for sustainable development, and vice versa. This assessment allows us to determine the desire for cooperation of each participant (entrepreneur, NGO, investor, university, government). The method has been tested on the basis of 12 associations for sustainable development, including 951 participants for 2021. Between 1964 and 2020, the importance of large entrepreneurs increased in associations for sustainable development, especially the chemical entrepreneurs. The growth rate and the share of other participants are insignificant compared to large entrepreneurs in the associations. Small and medium-sized entrepreneurs have barriers to entry into associations. It is necessary to form a partnership of all participants for the sustainable development at the same time.
Factors of formation of foreign language communicative competence of future construction specialists through overcoming the language barrier
Authors: Makayev Khanif , Makayeva Guzal , Sigacheva Natalia
Published: June 2021

Employees at construction sites need to have good communicative competence on all the issues occurring there. The survey of higher school students revealed presence of language barriers in the process of communication. They should be able to cope with all the speech situations requiring proper practical language skills. Therefore, the research considers necessity of development of communicative speech skills of future construction specialists in English considering the factors that would contribute to overcoming language barriers. To realize this, the authors empirically surveyed groups of a higher school final-year students to improve their language level through mastering their communicative skills on the base of necessary teaching factors, and simultaneously eliminating possible obstacles. The research was conducted on the base of communicative method and the teaching-practicing-controlling approach supported by observing, questioning, and surveying methods. The results obtained show that proper practical development of future specialists’ communicative skills taking into account all kinds of barriers can improve their professional language growth and overcoming their speech barriers. The research results obtained one can use in language teaching practice, as well as for making some possible contribution to education and through it communication skills of research participants’ speech development.
Cyclic annealing versus continuous annealing of 20 wt.% chromium white cast iron
Authors: Mandal Siddhartha Sankar , Mondal Dipak Kumar , Ghosh Karuna Sindhu
Published: June 2021

To destabilize as-cast microstructure of 20 wt.% chromium white iron, cyclic annealing involving repeated austenitization for short duration of 0.6 h at 900, 950, 1000, 1050 and 1100 °C followed by forced air cooling is conducted as an alternative to continuous annealing requiring austenitization for longer period of 4–6 h at the said temperatures followed by furnace cooling. Continuous austenitization destabilizes the austenite matrix through precipitation of secondary carbides and transforms the alloy depleted austenite to pearlite on furnace cooling, thereby reducing the as-cast hardness from HV 669 to HV466. In contrast, repeated austenitization not only destabilizes the austenite matrix through precipitation of secondary carbides followed by its transformation to martensite on forced air cooling, but also causes disintegration of longer eutectic carbides to shorter segments with subsequent increase in hardness to as high as HV 890. Notched impact toughness after both continuous and cyclic annealing remains uniformly at 12.0 J as compared to as-cast value of 6.0 J. Besides, an unexpected rise in abrasive wear resistance after cyclic annealing treatment makes the alloy superior than that obtained by continuous annealing treatment as practiced in industries.
Diagnosis and treatment modalities of hilar biliary duct stricture in hepatic cystic echinococcosis after endocystectomy
Authors: Shalayiadang Paizula , Abulizi Abduaini , Ahan Ayifuhan , Jiang Tiemin , Ran Bo , Zhang Ruiqing , Guo Qiang , Wen Hao , Shao Yingmei , Aji Tuerganaili
Published: June 2021

Aim: Hilar biliary duct stricture may occur in hepatic cystic echinococcosis (CE) patients after endocystectomy. This study aimed to explore diagnosis and treatment modalities. Methods: Clinical data of 26 hepatic CE patients undergoing endocystectomy who developed postoperative hilar biliary duct stricture were retrospectively analyzed and were classified into three types: type A, type B, and type C. Postoperative complications and survival time were successfully followed up. Results: Imaging showed biliary duct stenosis, atrophy of ipsilateral hepatic lobe, reactive hyperplasia, hepatic hilum calcification, and dilation or discontinuity of intrahepatic biliary duct. All patients received partial hepatectomy to resect residual cyst cavity and atrophic liver tissue, and anastomosis of hepatic duct with jejunum or common bile duct exploration was applied to handle hilar biliary duct stricture. Twenty-five patients were successfully followed up. Among type A patients, one patient died of organ failure, and upper gastrointestinal bleeding and liver abscess occurred in one patient. Moreover, calculus of intrahepatic duct was found in one type B and type C patient. Conclusion: Long-term biliary fistula, infection of residual cavity or obstructive jaundice in hepatic CE patients after endocystectomy are possible indicators of hilar bile duct stricture. Individualized and comprehensive treatment measures, especially effective treatment of residual cavity and biliary fistula, are optimal to avoid serious hilar bile duct stricture.
R-tree data structure implementation for Computer Aided Engineering (CAE) tools
Authors: Shelar Vaibhav , Subramani Selamani , Davidson Jebaseelan
Published: June 2021

Searching and handling geometric data are basic requirements of any Computer Aided Engineering application (CAE). Spatial search and local search has greater importance in CAD and CAE applications for reducing the model preparation time. There are many efficient algorithms being made to search geometrical data. Current neighbour search strategy is limited and not efficient in different CAE platforms. R-tree is tree data structure used for spatial access methods. This paper presents a review of R-tree data structure with its implementation in one of the CAE tool for neighbour search and local search. It satisfies current neighbour search requirements in CAE tools. Results shows considerable amount of time saving compared to the conventional approach. This work concludes that R-tree implementation can be helpful in identifying neighbour part and reducing model preparation time in CAD and CAE tools.
Prüfungsthema: Mangel und Überschuss
Authors: Schmid Eva C.
Published: June 2021

In diesem HPA-Prüfungstrainer beschäftigen sich alle Fragen mit Mangel und Überschuss.
Zusammenfluss statt Ausschluss
Authors: Bögel-Witt Martina
Published: June 2021

Fülle und Leere beziehungsweise Mangel gehören als Gegensatzpaar zu den acht Leitkriterien der TCM-Diagnostik und -Therapie. Wie alle Leitkriterien wurzeln auch sie im Grundprinzip von Yin und Yang. Unterschieden werden in der Praxis Yang-Fülle, Yang-Mangel, Yin-Fülle und Yin-Mangel. Der Beitrag zeigt exemplarisch diagnostische Besonderheiten und therapeutische Möglichkeiten. Wichtig für die Therapie ist zu unterscheiden, ob es sich um einen echten oder falschen beziehungsweise relativen Fülle- oder Mangelzustand handelt.
Religiosität und Spiritualität als Ressourcen in der Betreuung von Patienten mit Kopf-Hals-Tumoren
Authors: Vitek Petr , Koscielny Sven , Büssing Arndt , Hübner Jutta , Büntzel Jens
Published: June 2021

Fragestellung Spiritual Care ist ein etablierter Bestandteil einer ganzheitlichen Betreuung in der Palliativmedizin. Stellen Religiosität und Spiritualität auch eine Ressource in früheren Phasen der Erkrankung von Kopf-Hals-Tumorpatienten (KHT) dar?

Material und Methode An der prospektiven Studie nahmen 113 KHT-Patienten (27 Frauen, 84 Männer, 2 divers) teil. Der Fragebogen erfasste die momentane Belastungssituation (NRS), Spiritualität als Ressource (SpREUK-15), spirituelle Bedürfnisse (SpNQ-20), Krankheitsinterpretationen (IIQ) sowie die Lebenszufriedenheit der Patienten (BMLSS-10, BMLSS-Support, WHO-5). 39 Patienten befanden sich aktuell in Therapie, 74 in Langzeitbetreuung.

Ergebnisse Nur 31/111 (28 %) Patienten empfinden sich als religiös und/oder spirituell, 72 % als weder religiös noch spirituell. 51/111 Teilnehmer erkennen in der Reflexion über ihre Erkrankung eine Teil-Ressource zur Bewältigung der Lebenssituation. An spirituellen Bedürfnissen beschreiben sie: religiöse 35/112, existenzielle 67/112, innerer Frieden 90/112, Generativität 84/112. Neben der eigenen Religiosität ist das Stadium der Erkrankung eine Einflussgröße auf spirituelle Bedürfnisse und Ressourcen. Patienten mit Kopf-Hals-Tumoren neigen zu depressiven Verstimmungen (WHO-5 ≤ 50 %) und sind mit ihrer Lebens- und Unterstützungssituation tendenziell unzufrieden.

Schlussfolgerung 60–90 % der Kopf-Hals-Tumorpatienten haben spezifische spirituelle Bedürfnisse, die aber nicht immer erkannt werden. Moderne Konzepte integrativer Onkologie nehmen diese auf und stärken über diese Ressourcen die Lebensqualität und das Coping der Betroffenen.
Treatment of Primary Shoulder Stiffness: Results of a Survey on Surgeon Practice Patterns in Italy
Authors: Cucchi Davide , De Giorgi Silvana , Saccomanno Maristella F. , Uboldi Francesco , Menon Alessandra , Friedrich Max J. , Walter Sebastian G. , de Girolamo Laura
Published: June 2021

Objectives Shoulder stiffness is a condition of restricted glenohumeral range of motion (ROM), which can arise spontaneously or as consequence of a known cause. Several treatment options are available and currently no consensus has been obtained on which treatment algorithm represents the best choice for the patient. The aim of this study was to investigate surgeon practice patterns in Italy regarding treatment of primary shoulder stiffness.

Methods A literature review was performed to identify randomized controlled trials reporting results of shoulder stiffness treatment. The following controversial or critical points in the treatment of primary shoulder stiffness were identified: modalities of physical therapy; indication for oral corticosteroid; indication and frequency for injective corticosteroid; technique and site of injection; and indication, timing, and technique for surgery. A survey composed by 14 questions was created and administrated to the members of a national association specialized in orthopaedics and sports traumatology (SIGASCOT at the time of survey completion, recently renamed SIAGASCOT after the fusion of the societies SIGASCOT and SIA).

Results A total of 204 completed questionnaires were collected. Physical therapy was recommended by 98% of the interviewed. The use of oral corticosteroids was considered by 51%, and injections of corticosteroids by 72%. The posterior injection approach was the one preferred and a number of three was considered the upper limit for repeated injections. Injective therapy with local anesthetics and hyaluronic acid was considered by more than 20% of the interviewed. Thirty percent of the interviewed did not treat shoulder stiffness surgically.

Conclusion Several approaches to shoulder stiffness have been proposed and high-level evidence is available to analyze and discuss their results. Several controversial points emerged both from a literature review and from this national survey. Treatment of shoulder stiffness should be tailored to the patient's clinical situation and the stage of its pathology and should aim at pain reduction, ROM restoration, functional regain, and shortening of symptoms duration, with conservative therapy remaining the mainstay of treatment.
Subchondroplasty in the Treatment of Bone Marrow Lesions of the Knee: Preliminary Experience on First 15 Patients
Authors: Pasqualotto Stefano , Sgroi Andrea Vincenzo , Causero Araldo , Di Benedetto Paolo , Zorzi Claudio
Published: June 2021

Purpose The aim of this prospective study was to assess the effectiveness in terms of pain relief and functional improvement of the Subchondroplasty procedure in the treatment of osteoarthritis-related bone marrow lesions (BMLs) of the knee.

Methods The study included first 15 consecutive patients undergone to Subchondroplasty procedure for the treatment of chronic degenerative BMLs in which previous conservative treatment have failed. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, Knee Injury and Osteoarthritis Outcome Scores (KOOS), and visual analog scale (VAS) pain scores were obtained preoperatively and at 1, 6, and 12 months of follow-up.

Results WOMAC scores significantly improved from 39.7 ± 20.2 before surgery to 26.8 ± 16.1 at the 1-month follow-up (p = 0.045). A further significant improvement to 15.5 ± 12.7 (p = 0.02) and to 8.6 ± 3.1 (p < 0.01) was obtained both at 6-month and at 1-year follow-up. KOOS scores improved significantly from 47.5 ± 16.6 before surgery to 65.4 ± 14.9 at 1 month (p = 0.013) and to 80.4 ± 15.1 at 6-month follow-up (p = 0.01). A further improvement to 85.6 ± 15.1 was recorded 1 year postoperatively, although nonsignificant. VAS score showed a significant improvement from 55.8 ± 20.5 preoperatively to 36.2 ± 16.9 at 1 month (p = 0.008) and to 18.2 ± 17.3 at 6-month follow-up (p = 0.005). This further improved to 12.8 ± 17.9 at 1-year follow-up, although not significantly.

Conclusion Subchondroplasty procedure represents a safe and valid surgical option in the treatment of osteoarthritis-related BMLs of the knee, providing an improvement in terms of pain relief and functional recovery. Longer studies are required to evaluate how long these improvements may last.

Level of Evidence Therapeutic case-series, Level IV study.
Gyrokinetic benchmark of the electron temperature-gradient instability in the pedestal region
Authors: Hassan Ehab , Hatch D. R. , Guttenfelder W. , Chen Y. , Parker S.
Published: June 2021

Transport from turbulence driven by the electron temperature-gradient (ETG) instability is likely a major source of electron heat losses through the pedestal. Due to extreme gradients and strong shaping, ETG instabilities in the pedestal are distinct from those in the core, having, for example, multiple branches (toroidal and slab) in different wavenumber ranges. Due to its importance for pedestal transport, and its rather exotic character, a rigorous multi-code benchmarking exercise is imperative. Here, we describe such an exercise, wherein we have carried out a detailed comparison of local linear pedestal ETG simulations using three gyrokinetic codes, CGYRO, GEM, and GENE and testing different geometric parameters (such as circular, Miller, and equilibrium EFIT geometry). The resulting linear frequencies, growth rates, and eigenfunctions show very good agreement between the codes in the three types of employed geometries. A nonlinear benchmark between CGYRO and GENE is also described, exhibiting good agreement (a maximum of 20% difference in the heat fluxes computed) at two locations in the pedestal. This lays the foundation for confidently modeling ETG turbulence in the pedestal.
Sensitivity improvement of infrared imaging video bolometer for divertor plasma measurement
Authors: Mukai K. , Peterson B. J. , Ezumi N. , Shigematsu N. , Ohshima S. , Miyashita A. , Matoike R.
Published: June 2021

The sensitivity of an infrared imaging video bolometer (IRVB) was improved for the measurement of relatively low energy plasma radiation from the viewpoint of the metal foil absorber material. The photon energy of the radiation was considered up to 1 keV for the divertor plasma measurement. The thickness of the foil absorber was evaluated not only for conventional heavy elements, e.g., platinum, but also for light elements by the relation between the photon energy and attenuation length and by mechanical strength. A heat-transfer calculation using ANSYS suggested that light elements with practical foil thickness provide a higher temperature rise of the foil absorber compared with heavier elements with practical foil thickness. The maximum of the temperature rise was evaluated using He–Ne laser irradiation onto absorber samples. The material dependence of the temperature rise has a similar tendency between calculations and experiments. Experimentally, the sensitivity of the IRVB improved from 280 to 110 µW/cm2 using titanium with 1 µm thickness compared with conventional platinum with 2.5 µm thickness. Consequently, the signal-to-noise ratio of the IRVB could be improved from 2.8 to 9.1.
Observation of the critical state to multiple-type Dirac semimetal phases in KMgBi
Authors: Liu D. F. , Wei L. Y. , Le C. C. , Wang H. Y. , Zhang X. , Kumar N. , Shekhar C. , Schröter N. B. M. , Li Y. W. , Pei D. , Xu L. X. , Dudin P. , Kim T. K. , Cacho C. , Fujii J. , Vobornik I. , Wang M. X. , Yang L. X. , Liu Z. K. , Guo Y. F. , Hu J. P. , Felser C. , Parkin S. S. P. , Chen Y. L.
Published: June 2021

Dirac semimetals are classified into different phases based on the types of Dirac fermions. Tuning the transition among different types of Dirac fermions in one system remains a challenge. Recently, KMgBi was predicted to be located at a critical state in which various types of Dirac fermions can be induced owing to the existence of a flatband. Here, we carried out systematic studies on the electronic structure of KMgBi single crystals by combining angle-resolve photoemission spectroscopy and scanning tunneling microscopy/spectroscopy. The flatband was clearly observed near the Fermi level. We also revealed a small bandgap of ∼20 meV between the flatband and the conduction band. These results demonstrate the critical states of KMgBi that transition among various types of Dirac fermions can be tuned in one system.
Light–matter quantum dynamics of complex laser-driven systems
Authors: Gonoskov Ivan , Gräfe Stefanie
Published: June 2021

We propose a novel general approximation to transform and simplify the description of a complex fully quantized system describing the interacting light and matter. The method has some similarities to the time-dependent Born–Oppenheimer approach: we consider a quantum description of light rather than of nuclei and follow a similar separation procedure. Our approximation allows us to obtain a decoupled system for the light-excited matter and “dressed” light connected parametrically. With these equations at hand, we study how intense light as a quantum state is affected due to the back-action of the interacting matter. We discuss and demonstrate the possibility of the light-mode entanglement and nonclassical light generation during the interaction.
Cherenkov radiation in integrated nanophotonic structures
Authors: Salas-Montiel Rafael
Published: June 2021

Vavilov–Cherenkov radiation (CR), an electromagnetic radiation emission that occurs when a charged particle in a medium moves faster than the speed of light in the same medium, plays an important role in many areas of physics such as nuclear physics. Recently, CR has been investigated in photonics and plasmonics in the perspective of its application in velocity-dependent particle detection to enhance current particle detectors, thanks to the flexibility that offer integrated devices. In this contribution, the description of the excitation of eigenmodes in different integrated photonic and plasmonic structures by a uniformly moving charged particle is numerically presented. The CR that arise from such an interaction is described within the framework of an eigenmode analysis and validated with source and field propagation with the use of the finite-difference time-domain method. Integrated nanophotonics could provide a promising platform for the investigation of the interaction between electrons and photons on-chip.
Classification of minimal Z2×Z2-graded Lie (super)algebras and some applications
Authors: Kuznetsova Zhanna , Toppan Francesco
Published: June 2021

This paper presents the classification over the fields of real and complex numbers, of the minimal Z2×Z2-graded Lie algebras and Lie superalgebras spanned by four generators and with no empty graded sector. The inequivalent graded Lie (super)algebras are obtained by solving the constraints imposed by the respective graded Jacobi identities. A motivation for this mathematical result is to systematically investigate the properties of dynamical systems invariant under graded (super)algebras. Recent works only paid attention to the special case of the one-dimensional Z2×Z2-graded Poincaré superalgebra. As applications, we are able to extend certain constructions originally introduced for this special superalgebra to other listed Z2×Z2-graded (super)algebras. We mention, in particular, the notion of Z2×Z2-graded superspace and of invariant dynamical systems (both classical worldline sigma models and quantum Hamiltonians). As a further by-product, we point out that, contrary to Z2×Z2-graded superalgebras, a theory invariant under a Z2×Z2-graded algebra implies the presence of ordinary bosons and three different types of exotic bosons, with exotic bosons of different types anticommuting among themselves.
Non-axisymmetric droplet irradiation effects on ion and extreme ultraviolet light emission of laser-produced plasma light sources
Authors: Brandstätter Markus , Weber Marco M. , Abhari Reza S.
Published: June 2021

Extreme ultraviolet (EUV) light emission and ion emissions in the lateral direction generated by Nd:YAG irradiated droplet targets were studied experimentally under non-axisymmetric droplet irradiation. EUV energy monitors and ion electrostatic probes were positioned symmetrically at fixed positions around the plasma. Bulk ion kinetic energy Ekin and bulk ion density ni were characterized for angles of γ=31° to γ=90° from the laser axis in a low-pressure nitrogen atmosphere of 1×10−2mbar. The EUV light emission reached a maximum level, with an increase of 5%, at γ=60° through a shift of the droplet by around 18% of the droplet diameter. The ion bulk kinetic energies at 31° and 75° also increased by 9% and 15%, respectively, with a small increase in ion density of around 3%. Intentional offset of the droplet target can, therefore, potentially result in higher EUV light output for non-axisymmetric mirror configurations, at the expense of a higher ion load but a decreased droplet fragment load. The ion kinetic energy showed a strongly anisotropic expansion behavior when offsetting the droplet relative to the laser focus, with kinetic energies increasing up to 60% in the lateral direction by offsetting the droplet by more than 0.5 droplet diameters for a lateral range of 31°–90°. The ion density showed a more isotropic change with droplet offset, while maintaining a forward-peaked distribution.
Transparent conductive electrodes based on co-sputtered ultra-thin metal layers for semi-transparent perovskites solar cells
Authors: Spinelli Pierpaolo , Fuentes Pineda Rosinda , Scigaj Mateusz , Ahmad Taimoor , Wojciechowski Konrad
Published: June 2021

Back contact transparent conductive electrodes are essential components of semi-transparent perovskite solar cells, which are especially beneficial for tandem photovoltaics. In this Letter, we present a way to realize ultrathin metal layers in ITO-metal-ITO (IMI) electrode stacks, which are characterized by the superior infrared transmittance and electrical conductivity. The metal layers are deposited by the co-sputtering technique, which enables the realization of smooth metallic films, as thin as 5 nm. We applied the IMI electrodes to flexible high bandgap perovskite solar cells and demonstrated that the IMI electrodes based on the co-sputtered metals are outperforming the standard ITO electrodes in terms of cell performance, while maintaining similar transmission values. Furthermore, we show that the IMI electrodes are significantly more flexible than the standard ITO and, thus, are more suitable for flexible optoelectronic devices. The co-sputtering technique is compatible with the industrial production process. Overall, the co-sputtered IMI stack presented in this work paves the way for the commercial utilization of semi-transparent (visible or near-infrared range) photovoltaic devices, including high-efficiency tandem applications and window-integrated photovoltaics.
Solid-structure impact pattern of a vortex-induced oscillating flexible pipeline in the vicinity of a bottom wall boundary
Authors: Zhu Hongjun , Zhao Honglei
Published: June 2021

The vortex-induced vibration and solid-structure impact of a neutrally buoyant horizontal flexible pipe in the vicinity of a bottom wall boundary are experimentally investigated in a water flume. The pipe with an aspect ratio of 87 is arranged with an oblique angle of 30° and an initial gap-to-diameter ratio of 0.5. A non-intrusive measurement with two high-speed cameras is employed to simultaneously capture the spatial-temporal vibration displacements in both inline and crossflow directions, and the pipe-wall impact process in the reduced normal velocity range of 3.40–14.43 with a maximum Reynolds number of 2780. Experimental results highlight the new pipe equilibrium profiles deviating away from the bottom boundary due to the wall proximity and wall collision. The occurrence of wall-impact is determined by whether the crossflow amplitude is larger or equal to the summation of the new equilibrium position and initial gap. The observed five distinct solid-pipe impact patterns as well as the location and length of the impacting segments are closely associated with the dominant response mode and the space-varying response amplitude. Particularly, the response mode competition contributes to the spatial shift of impacting position over time.
Dynamics in the plastic crystalline phase of cyanocyclohexane and isocyanocyclohexane probed by 1H field cycling NMR relaxometry
Authors: Carignani Elisa , Flämig Max , Calucci Lucia , Rössler Ernst A.
Published: June 2021

Proton Field-Cycling (FC) nuclear magnetic resonance (NMR) relaxometry is applied over a wide frequency and temperature range to get insight into the dynamic processes occurring in the plastically crystalline phase of the two isomers cyanocyclohexane (CNCH) and isocyanocyclohexane. The spin-lattice relaxation rate, R1(ω), is measured in the 0.01–30 MHz frequency range and transformed into the susceptibility representation χNMR″ω=ωR1ω. Three relaxation processes are identified, namely, a main (α-) relaxation, a fast secondary (β-) relaxation, and a slow relaxation; they are very similar for the two isomers. Exploiting frequency–temperature superposition, master curves of χNMR″ωτ are constructed and analyzed for different processes. The α-relaxation displays a pronounced non-Lorentzian susceptibility with a temperature independent width parameter, and the correlation times display a non-Arrhenius temperature dependence—features indicating cooperative dynamics of the overall reorientation of the molecules. The β-relaxation shows high similarity with secondary relaxations in structural glasses. The extracted correlation times well agree with those reported by other techniques. A direct comparison of FC NMR and dielectric master curves for CNCH yields pronounced difference regarding the non-Lorentzian spectral shape as well as the relative relaxation strength of α- and β-relaxation. The correlation times of the slow relaxation follow an Arrhenius temperature dependence with a comparatively high activation energy. As the α-process involves liquid-like isotropic molecular reorientation, the slow process has to be attributed to vacancy diffusion, which modulates intermolecular dipole–dipole interactions, possibly accompanied by chair–chair interconversion of the cyclohexane ring. However, the low frequency relaxation features characteristic of vacancy diffusion cannot be detected due to experimental limitations.
Flow and fouling in elastic membrane filters with hierarchical branching pore morphology
Authors: Chen Zhengyi , Liu Shi Yue , Christov Ivan C. , Sanaei Pejman
Published: June 2021

Filtration is widely used in industry; therefore, prediction of filtration efficacy and analysis of filter performance are essential. Real membranes have complex internal geometry: pores inside the membrane branch and interconnect with each other, which must be taken into account in mathematical models of filtration. Membrane fouling, as an unavoidable consequence of removing particles, occurs in the course of filtration and deteriorates the membrane permeability. In addition, for membranes made of elastic materials, the pressure within the membrane results in expansion of the pore radii. The pore expansion competes with particle deposition to delay fouling and, thus, influences filtration performance. In this paper, we develop a mathematical model of flow and fouling of such elastic membrane filters with multi-layer bifurcating (hierarchical) interior morphology. Two filtration forcing mechanisms through the membrane are considered: (i) constant pressure drop and (ii) constant flux. We investigate how filtration behaves under these two forcing mechanisms and mathematically describe the morphology change due to fouling coupled to elastic pore expansion. In particular, we obtain an analytical solution for the deformation of the elastic pore walls, which is easily incorporated into the filtration model. Our model provides a quantitative mathematical framework to predict the impact of hierarchical pore morphology and the elasticity of pore walls on filtration performance.
Aggregation and dynamics of soil organic matter under different management systems in the Brazilian Cerrado
Authors: Torres José Luiz Rodrigues , Silva Venâncio Rodrigues e , Costa Danyllo Denner de Almeida , Pereira Marcos Gervasio , Assunção Shirlei Almeida , Gonzalez Antonio Paz , Pinto Luiz Alberto da Silva Rodrigues , Loss Arcangelo
Published: June 2021

The objectives of this study were to evaluate the stability of aggregates, and quantify the contents and stocks of total organic carbon (TOC), and granulometric and humic fractions of soil organic matter (SOM). Four management systems were evaluated: (1) a no-tillage system (NTS) implemented 5 years ago (NTS5); (2) NTS implemented 17 years ago (NTS17); (3) conventional tillage system (CTS) implemented 20 years ago (CTS20); and (4) native Cerrado vegetation. For each system, five undeformed and five deformed soil samples were collected from the 0.00–0.05, 0.05–0.10, 0.10–0.20, and 0.20–0.40 m layers. The weighted mean diameter (WMD), TOC, stock of carbon (StockC), organic carbon particulate (OCp), organic carbon associated with minerals (OCam), stock of OCp, stock of OCam, carbon stock index, carbon management index (CMI), organic carbon in the fulvic acid fraction (FAF), humic acid fraction (HAF), and humin fraction were quantified. The WMD and CMI values increased as the soil management intensity decreased. The adoption of the NTS increased the WMD and the contents, stocks, and proportions of TOC in the more labile granulometric and humic (FAF/HAF) fractions of the SOM. The WMD, CMI, granulometric and chemical fractionation of the SOM were more efficient than the TOC and StockC in identifying the differences between the management systems. Due to the higher contents of the more labile fractions of SOM, the granulometric and chemical fractionation of SOM in the NTS5 and NTS17 systems had higher values of WMD and CMI than the CTS20 system.
Soil microbiome after nine years of fly ash dump spontaneous revegetation
Authors: Naumova Natalia , Belanov Ivan , Alikina Tatiana , Kabilov Marsel
Published: June 2021

Fly ash dumps of thermal power stations have been increasing in area worldwide due to the growing demand for power. One of the cost-effective approaches for restoring such sites is spontaneous revegetation in those areas where adjacent indigenous ecosystems can supply seeds and living organisms. We assessed microbiome taxonomic diversity in a Technosol developed during nine years of spontaneous revegetation of the terminated fly ash pond of a thermal power station in Novosibirsk, Russia, in comparison with microbiome diversity in undisturbed Phaeozem under adjacent birch forest by using 16S (V3–V4) and ITS2 (ITS3–ITS4) amplicon sequencing with Illumina MiSeq. We identified 577 fungal and 5542 bacterial operational taxonomic units (OTUs); 95–99% of them were minor or rare species. The dominant OTUs were completely different in the studied soils. At the phylum level, the ultimate dominants were Ascomycota (84%) in the Technosol and Basidiomycota (89%) in the Phaeozem. Three phyla (Proteobacteria, Acidobacteria and Actinobacteria), together comprising more than a half of the bacteriobiome, prevailed in both soils; however, at the OTU level, soil-related differences were found for 31% of the OTUs. The Technosol bacteriobiome was less structured and more diverse compared to the mycobiome, displaying the same phylum-level structure and OTU-based α-biodiversity as in the adjacent mature soil. Our finding that few fungal and bacterial OTUs dominated in the soil microbiome, the majority being minor or rare members, implies that key ecosystem processes performed by soil microorganisms rely on a very limited taxonomic diversity, both in young and mature soils.
Study on the Al2O3p/Al composites prepared by Al-calcined kaolin system
Authors: Zhang Ting , Chen Gang , Zhang Zhenya , Zhao Yutao , Xu Jiasheng , Zhang Chentingying , Ding Dali
Published: June 2021

In this study, in-situ Al2O3p/Al composite was prepared by the exothermic dispersion method from Al-calcined kaolin system. Thermodynamic analysis was carried out by calculating Gibbs free energy. The reaction kinetics of the system was studied by differential scanning calorimetry and Kissinger equation. The effects of heating temperature and holding time on the microstructure of the composites were analysed. The results showed that the reaction activation energy of the system continued to increase with the progress of the reaction. With the extension of the reaction time at 800°C, the particle size of Al2O3 increased slowly. When the holding time was 50 min, the density and hardness of the composite material were 2.7 g cm−3 and 64HV respectively.
Connecting people and voices for radical change in Africa
Authors: Zeilig Leo
Published: June 2021

In this new section of the journal, we aim to give readers of the print journal a picture of what’s been published on Roape.net over the last few months, and invite you to connect and follow the articles, blogposts, authors and debates online. Details of all the blogposts referred to here are in the reference list at the end. We warmly invite all our readers to sign up to the Roape.net newsletter by entering their email address at the top of the home page of the website.
Profiles of Young Women's Alcohol and Cannabis use Linked to Risk for Sexually Transmitted Infection Highlight the Importance of Multi-Level Targeted Interventions: Findings from the Pittsburgh Girls Study
Authors: Chung Tammy , Hipwell Alison E. , Stepp Stephanie D. , Miller Elizabeth , Sartor Carolyn E.
Published: June 2021

Background: Social ecological models designed to understand disparities in sexually transmitted infection (STI) prevalence highlight understudied structural and community risk factors. Guided by a social ecological model, this study identified profiles based on substance use-related STI risk, and examined associations of the profiles with selected indicators of structural-, community-, and individual-level STI risk factors. Methods: Repeated measures latent class analysis was applied to Pittsburgh Girls Study data ( n = 2,138; 58% Black, 42% White) at ages 18–20. Profile indicators included: women's and partner's alcohol and cannabis use, women's sexual risk behavior, and self-reported STI. Profile predictors included racial background, structural-, community-, and individual-level risk factors. Results: Two of the five identified profiles had low STI likelihood: “Low Use” of alcohol and cannabis (25.5%; overrepresented by Black women), and “Alcohol Only” (19.1%; overrepresented by White women). Three profiles, all representing co-use of alcohol and cannabis, had higher STI likelihood: “Co-Use: Increasing Alcohol and Occasional Cannabis use” (16.5%; overrepresented by White women), “Co-Use: Occasional Alcohol and Cannabis use” (26.1%; overrepresented by Black women), and “Co-Use: Frequent Cannabis and Occasional Alcohol use” (12.8%; overrepresented by Black women). Structural STI risk (household use of public assistance at wave 1) was associated with “Low Use” and “Co-Use: Frequent Cannabis and Occasional Alcohol use” profiles. STI risk at multiple levels (structural, neighborhood, individual) was associated with the “Co-Use: Frequent Cannabis and Occasional Alcohol use” profile. Conclusions: Co-use of alcohol and cannabis is an important target for STI prevention efforts. Results also highlight structural- and community-level STI risk factors that disproportionately impact Black women, and the importance of multi-level interventions that are targeted to profile of risk to optimize the effectiveness of interventions.