bluuebunny/crossref_metadata_2025 huggingface dataset:
Peripersonal space in the front, rear, left and right directions for audio-tactile multisensory integration
Authors: Matsuda Yusuke , Sugimoto Maki , Inami Masahiko , Kitazaki Michiteru
Published: May 2021

Peripersonal space (PPS) is important for humans to perform body–environment interactions. However, many previous studies only focused on the specific direction of the PPS, such as the front space, despite suggesting that there were PPSs in all directions. We aimed to measure and compare the peri-trunk PPS in four directions (front, rear, left, and right). To measure the PPS, we used a tactile and an audio stimulus because auditory information is available at any time in all directions. We used the approaching and receding task-irrelevant sounds in the experiment. Observers were asked to respond as quickly as possible when a tactile stimulus was applied to a vibrator on their chest. We found that peri-trunk PPS representations exist with an approaching sound, irrespective of the direction.
A Japanese traditional medicine Hochuekkito promotes negative conversion of vancomycin-resistant Enterococci
Authors: Kohno Junko , Kawamura Tsuyoshi , Kikuchi Akiko , Akaishi Tetsuya , Takayama Shin , Ishii Tadashi
Published: May 2021

Vancomycin-resistant enterococci (VRE) are prominent causes of nosocomial infections. Japanese traditional (Kampo) medicine promotes intestinal immunity and protects against bacterial infections. We assessed potential differences in the clinical course of VRE-positive patients, based on their characteristics and treatment with Kampo medicines. This retrospective observational study collected data from VRE-positive patients from August 2018 to July 2019 at a tertiary-care hospital in Japan. The data of 122 consecutive VRE-positive inpatients were analyzed. Sixty-nine patients were treated with probiotics, among whom, 18 were further treated with Kampo medicines. Twenty-six of the 122 patients subsequently died. In univariate analyses, subsequent VRE negative conversion significantly reduced the mortality of VRE-detected patients (p = .0003). Administration of probiotics (p = .0065) and Kampo medicines with probiotics (p = .0002), especially of the Kampo medicine hochuekkito (p = .0014), and a higher serum albumin level positively contributed to the subsequent VRE negative conversion. Multivariate analyses demonstrated that Kampo medicines and body mass index contributed to VRE negative conversion. Hochuekkito shortened the time needed for VRE negative conversion (p = 0.0485). Administration of Kampo medicines, especially of hochuekkito, in addition to probiotics in VRE patients may promote VRE negative conversion.
Relationship of epidural patient-controlled analgesia with postoperative bleeding after unilateral total knee arthroplasty: a propensity score-matching analysis
Authors: Hahm Kyung-Don , Jin Seok-Joon , Cho Seong-Sik , Park Jihoon , Park Han , Kim Doo-Hwan , Choi Seong-Soo
Published: May 2021

Although epidural patient-controlled analgesia (PCA) to control postoperative pain after total knee arthroplasty (TKA), the relationship of epidural PCA with postoperative bleeding remains controversial. Therefore, we aimed to evaluate the effect of epidural and intravenous PCA on postoperative bleeding in patients undergoing unilateral TKA. Total of 2467 patients who underwent TKA were divided to intravenous PCA (n = 2339) or epidural PCA (n = 128) group. After 1:1 propensity score-matching, 212 patients were analyzed to assess the associations between the perioperative blood loss and epidural PCA between the groups. Mean postoperative blood loss was significantly greater in epidural PCA than in intravenous PCA (900.9 ± 369.1 mL vs. 737.8 ± 410.1 mL; P = 0.007). The incidence of red blood cell (RBC) administration (> 3 units) was significantly higher in epidural PCA than in intravenous PCA (30.2% vs. 16.0%; OR 2.5; 95% CI 1.201–5.205; P = 0.014). Epidural PCA may be strongly related to postoperative bleeding and the incidence of RBC transfusion of more than 3 units after unilateral TKA, as compared to intravenous PCA. Therefore, the use of epidural PCA may be carefully considered for postoperative pain management in TKA.
Author Correction: Fine dissection of the tarsal tunnel in 60 cases
Authors: Yang Y. , Du M. L. , Fu Y. S. , Liu W. , Xu Q. , Chen X. , Hao Y. J. , Liu Z. , Gao M. J.
Published: May 2021

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Moisture channels and pre-existing weather systems for East Asian rain belts
Authors: Cheng Tat Fan , Lu Mengqian , Dai Lun
Published: May 2021

Rain belts in East Asia frequently pose threats to human societies and natural systems. Advances in a skillful forecast on heavy precipitation require a deeper understanding of the preconditioned environments and the hydrologic cycle. Here, we disentangle 15 dominant moisture channels along four corridors reaching the Somali Jet, South Asia, Bay of Bengal, and Pacific basin for the warm-season rain belts. Among them, the Somali and South Asian channels were underappreciated in the literature. The results also highlight the importance of terrestrial moisture sources, and the close relationship between the moisture pathways and rain belts’ characteristics. Back-tracing the weather within a 2-week lead time reveals the pre-existing weather systems and circumglobal wave trains, that govern the moisture channels. Findings from this work develop a better understanding of East Asian rain belts’ water cycle, and may offer insights into model evaluation and heavy rainfall prediction at a longer lead time.
Surface forces and stratification in foam films formed with bile salts
Authors: Kemal Subinur Ilshat , Uribe Ortiz Camila Alexandra , Sharma Vivek
Published: May 2021

We report the discovery and characterization of stratification in freely draining ultrathin, micellar foam films formed with bile salt solutions.
Mitochondria-targeted ratiometric fluorescent imaging of cysteine
Authors: Wei Ya-Nan , Lin Bo , Shu Yang , Wang Jian-Hua
Published: May 2021

The probe ANET is developed for cysteine imaging, and it has the advantages of mitochondrial targeting capability, ratiometric fluorescence, high selectivity, and a large Stokes shift.
Visualization of USPIO-labeled melt-electrowritten scaffolds by non-invasive magnetic resonance imaging
Authors: Mueller Kilian M. A. , Topping Geoffrey J. , Schwaminger Sebastian P. , Zou Younzhe , Rojas-González Diana M. , De-Juan-Pardo Elena M. , Berensmeier Sonja , Schilling Franz , Mela Petra
Published: May 2021

Composite scaffolds with controlled micro-architecture were fabricated by melt electrowriting and rendered MRI visible by embedded USPIOs to foster clinical translation.
Z-Selective Pd-catalyzed 2,2,2-trifluoroethylation of acrylamides at room temperature
Authors: Ruyet Louise , Lapuh Maria I. , Koshti Vijay S. , Földesi Tamás , Jubault Philippe , Poisson Thomas , Novák Zoltán , Besset Tatiana
Published: May 2021

A straightforward methodology for the selective synthesis of high-value added Z-2,2,2-trifluoroethylated acrylamides by Pd-catalyzed C–H bond activation at room temperature.
Spectroscopic investigations of electron and hole dynamics in MAPbBr3 perovskite film and carrier extraction to PEDOT hole transport layer
Authors: Niedzwiedzki Dariusz M. , Kouhnavard Mojgan , Diao Yifan , D'Arcy Julio M. , Biswas Pratim
Published: May 2021

Characterization of photophysical properties of MAPbBr3 perovskite film with application of various static and time-resolved spectroscopies and evaluation of hole extraction process in the FTO/RVPP-PEDOT/MAPbBr3 architecture.
Thermoelectric properties of CZTS thin films: effect of Cu–Zn disorder
Authors: Isotta E. , Syafiq U. , Ataollahi N. , Chiappini A. , Malerba C. , Luong S. , Trifiletti V. , Fenwick O. , Pugno N. M. , Scardi P.
Published: May 2021

The electronic properties of thin-film Cu2ZnSnS4 are remarkably affected by Cu–Zn disorder showing potential for tunability and diagnostic purposes.
Cell-permeable lanthanide–platinum(iv) anti-cancer prodrugs
Authors: Yao Kezi , Karunanithy Gogulan , Howarth Alison , Holdship Philip , Thompson Amber L. , Christensen Kirsten E. , Baldwin Andrew J. , Faulkner Stephen , Farrer Nicola J.
Published: May 2021

Heterometallic Eu/Gd Pt(iv) complexes have been synthesised and characterised. The Eu–Pt(iv) complex shows a luminescent “switch-on” effect upon reduction.
Stepwise optimization of genetic RuBisCO-equipped Escherichia coli for low carbon-footprint protein and chemical production
Authors: Tan Shih-I , Ng I-Son
Published: May 2021

The Genomic RuBisCO Equipped E. coli Neutralizer (GREEN) workhorse is a microbial cell factory for simultaneous low-carbon footprint protein and chemical production.
Bio-inspired fractal textile device for rapid sweat collection and monitoring
Authors: Chen Yen-Chi , Shan Siang-Sin , Liao Yu-Te , Liao Ying-Chih
Published: May 2021

A fractal collector with rapid sampling and high absorption flux is developed and combined with sensors for sweat real-time monitoring.
Cotton fabric loaded with self-dispersive and reactive biphasic TiO2 for durable self-cleaning activity and ultraviolet protection
Authors: Qi Zhenming , Wang Kuang , Chen Jiayi , Gao Dawei , Ren Yu , Wang Chunxia
Published: May 2021

Self-dispersive and reactive biphasic TiO2 (TiO2/KH550/SAT) with negative charge was achieved by introducing sulfonic groups and chlorine atoms, respectively, and combined with cotton fabric by the covalent bonding.
Mannosylated adamantane-containing desmuramyl peptide recognition by the NOD2 receptor: a molecular dynamics study
Authors: Maršavelski Aleksandra , Paurević Marija , Ribić Rosana
Published: May 2021

The dipeptide isoGln moiety of ManAdDMP significantly contributes to the binding to the NOD2 receptor. Loops 2 and 7 are important for ligand recognition and could be useful for further investigation of NOD2 activation/inhibition.
Enhanced upconversion luminescence and optical thermometry in Er3+/Yb3+ heavily doped ZrO2 by stabilizing in the monoclinic phase
Authors: Wang Kexiu , Wu Hao , Pan Guo-Hui , Wu Huajun , Zhang Liangliang , Zhang Jiahua
Published: May 2021

Stabilizing monoclinic ZrO2:Er3+,Yb3+ by doping with Nb5+ and realizing dual-color complementary thermometry.
Marine polysaccharides: green and recyclable resources as wound dressings
Authors: Jing Xiaodong , Sun Yanzhen , Ma Xiaoli , Hu Hao
Published: May 2021

This review summarizes the development and utilization of marine polysaccharides in wound dressings. The commonly used marine polysaccharides are classified, and the types of marine polysaccharide-based wound dressings are described in detail.
Novel fabrication of a yeast biochar-based photothermal-responsive platform for controlled imidacloprid release
Authors: Mei Meng , Bai Bo , Zheng Dan , Hu Na , Wang Honglun
Published: May 2021

The yeast biochar-based platform exhibited excellent photothermal conversion capability, and realized light-triggered controlled release of IMI.
Magnetic GO/Fe3O4 for rapid malachite green (MG) removal from aqueous solutions: a reversible adsorption
Authors: Li Wenwen , Xu Miaoqing , Cao Qian , Luo Jie , Yang Shiyong , Zhao Guangchao
Published: May 2021

MG adsorbed onto magnetic GO/Fe3O4 by electrostatic interaction and π–π band.
Ultra-wideband self-powered photodetector based on suspended reduced graphene oxide with asymmetric metal contacts
Authors: Hu Qianqian , Cao Yang , Liu Yu , Wang Yingxin , Wang Chenfeng , Zhu Jia-Lin , Yang Ning , Chu Weidong , Ma Wanyun , Sun Jia-Lin
Published: May 2021

An ultra-wideband self-powered photodetector based on suspended reduced graphene oxide with asymmetric metal contacts is reported.
Student success and the high school-university transition: 100 years of chemistry education research
Authors: Stone David C.
Published: May 2021

The 100th anniversary of the first article (published in 1921) examining student success and the high school to university transition in chemistry provides an excellent opportunity to consider what has – and has not – changed in chemistry education. This review details the development and findings of chemistry education research specifically as it relates to student learning and success over this extended time period. After considering the changing educational context and definition of success, this research will be described under three main themes: different ways of knowing (learning objectives and outcomes), thinking (scientific reasoning and problem solving), and learning (preferences and approaches to studying). A key finding is that while our understanding of effective teaching and learning has advanced significantly since the early 1900s, so too have the curriculum expectations and cognitive demands placed upon students increased significantly. Thus despite the many advances and innovations in chemistry education, an achievement gap persists between high school and post-secondary education for many students to this day. A comprehensive picture of the factors influencing student success developed from the research literature not only helps understand this disconnect; it also provides an opportunity to reflect on lessons learned for teaching, learning, and directions for future research.
Catechol-driven self-assembly to fabricate highly ordered and SERS-active glycoadjuvant patterns
Authors: Shen Shuyi , Huang Yan , Sun Yue , Zhang Weidong
Published: May 2021

The confined catechol-driven self-assembly possess the patterning and self-assembled abilities to form highly ordered glycoadjuvant surface, which exhibits higher Raman signals of carbohydrate.
Improving electron injection and transport in polymer field-effect transistors with guanidino-functionalized aromatic n-dopants
Authors: Schneider Severin , Gotthardt Jan M. , Steuer Lena , Leingang Simone , Himmel Hans-Jörg , Zaumseil Jana
Published: May 2021

The application of n-dopants in organic field-effect transistors (FETs) enables improvement of electron injection and transport.
Functional role of residues involved in substrate binding of human 4-hydroxyphenylpyruvate dioxygenase
Authors: Huang Chih-Wei , Hwang Chi-Ching , Chang Yung-Lung , Liu Jen-Tzu , Wu Sheng-Peng , Huang Kai-Ling , Huang Wei-min , Lee Hwei-Jen
Published: May 2021

4-Hydroxylphenylpyruvate dioxygenase (HPPD) catalyzes the conversion of 4-hydroxylphenylpyruvate (HPP) to homogentisate, the important step for tyrosine catabolism. Comparison of the structure of human HPPD with the substrate-bound structure of A. thaliana HPPD revealed notably different orientations of the C-terminal helix. This helix performed as a closed conformation in human enzyme. Simulation revealed a different substrate-binding mode in which the carboxyl group of HPP interacted by a H-bond network formed by Gln334, Glu349 (the metal-binding ligand), and Asn363 (in the C-terminal helix). The 4-hydroxyl group of HPP interacted with Gln251 and Gln265. The relative activity and substrate-binding affinity were preserved for the Q334A mutant, implying the alternative role of Asn363 for HPP binding and catalysis. The reduction in kcat/Km of the Asn363 mutants confirmed the critical role in catalysis. Compared to the N363A mutant, the dramatic reduction in the Kd and thermal stability of the N363D mutant implies the side-chain effect in the hinge region rotation of the C-terminal helix. The activity and binding affinity were not recovered by double mutation; however, the 4-hydroxyphenylacetate intermediate formation by the uncoupled reaction of Q334N/N363Q and Q334A/N363D mutants indicated the importance of the H-bond network in the electrophilic reaction. These results highlight the functional role of the H-bond network in a closed conformation of the C-terminal helix to stabilize the bound substrate. The extremely low activity and reduction in Q251E's Kd suggest that interaction coupled with the H-bond network is crucial to locate the substrate for nucleophilic reaction.
A beginner’s guide to X-ray data processing
Authors: Powell Harold R.
Published: May 2021

Single crystal X-ray diffraction is currently the most popular method for accurately determining the structure of molecules and is used for samples containing a few to many thousands of atoms in both biology and chemistry. Following data collection, the individual diffraction images need to be processed into a single dataset containing intensity information about all the contributing X-ray reflections.
Design and electric field analysis of novel winding structures with fillets for medium frequency transformers
Authors: Wang Tao , Yuan Jiansheng
Published: May 2021

The medium frequency transformer (MFT) has a significant role in large‐capacity DC–DC convertors, whereas the design of insulation under compact structures remains a critical challenge. Generally, the electric field strength near the winding edges is much larger than other positions. To fulfil insulation requirements, the distance between windings and the magnetic core needs to be enlarged, which also expands the window area of the core and the total volume of the MFT. A series of winding structures with fillets is proposed, including constructing winding fillets with reshaped foil and adopting different techniques to fillet the foil. The finite‐element method is used to analyse the insulation effects of various winding structures with fillets, conducted under diverse voltage levels and insulation materials commonly used in MFTs. The structures can substantially reduce the local electric field strength, further compressing the volume of the MFT.
Effect of synergetic control in hybrid PV‐Wind system response
Authors: Mars Nadia , Houcine Lassad , Zaafouri Abderrahman , Chaari Abdelkader
Published: May 2021

This paper presents a non‐linear controller based in synergetic controller (SC) that used for Wind and PV systems to reduce the chattering phenomenon, tracks rapidly and maintain the Maximum Power Point (MPP) under different environmental and load conditions. To approve the effectiveness of the proposed approach, comparative analysis of MPPT controller built using Perturb and observation for PV system and torque vector for Wind power system, with MPPT controller implemented using synergetic control in the both renewable sources in the hybrid system. The results show that SC MPPT is robust and maintain the power balancing with meeting multiple objectives of standalone hybrid systems such as rapidity of response, robustness under the external variations and no chattering problem as compared with the other controllers.
Study of the pitch behaviour of large‐scale wind turbines based on statistic evaluation
Authors: Liu Deshun , Zhang Fan , Dai Juchuan , Xiao Xiaocong , Wen Zejun
Published: May 2021

Pitch control is a basic function of large‐scale wind turbines to improve energy capture efficiency. Pitch
system is also a component system with a high failure rate due to the complex
pitch behaviour. It is helpful to the practical design and control if a clear
pitch behaviour is obtained. However, pitch behaviour is affected by the
structure of wind turbines, control strategies, wind resource characteristics,
and so on. So, there is still a lack of sufficient understanding. In this
study, the pitch behaviour of a 2 MW wind turbine is investigated based on
SCADA data. Four key evaluation indicators describing pitch behaviour are
proposed, which include pitch status, pitch time consumption, pitch angle peak,
and mean pitch angle. Moreover, the SCADA data extraction algorithm for pitch
behaviour investigation is also given. Then, the pitch behaviour is
investigated based on statistical evaluation. Some valuable conclusions have
been given. For example, for the investigated wind turbine, the time
proportions for the four states (non‐pitch,
increasing pitch, pausing pitch, and decreasing pitch) are 85.80%, 5.97%,
1.45%, and 6.78%, respectively. The pitch cycles, pitch angle peak, and mean
pitch angle increase with the increase of the standard deviation of wind speed.
Twelve-year update of the MST catalogue of γ-ray source candidates above 10 GeV and at Galactic latitudes higher than 20°
Authors: Campana R. , Massaro E.
Published: May 2021

We present an updated version catalogue of γ-ray source candidates, 12Y-MST, selected using the minimum spanning tree (MST) algorithm on the 12-year Fermi-LAT sky (Pass 8) at energies higher than 10 GeV. The high-energy sky at absolute Galactic latitudes above 20° has been investigated using rather restrictive selection criteria, resulting in a total sample of 1664 photon clusters, or candidate sources. Of these, 230 are new detections, that is, candidate sources without any association in other γ-ray catalogues. A large fraction of them have interesting counterparts, most likely blazars. We describe the main results on the catalogue selection and search of counterparts. We also present an additional sample of 224 candidate sources (12Y-MSTw), which are clusters that we extracted by applying weaker selection criteria: about 57% of them have not been reported in other catalogues.
Bitumen aging on the surface of crushed limestone at high temperatures
Authors: Salihov Muhammet , Veyukov Evgeniy , Lomakina Ekaterina , Malyanova Lidia
Published: May 2021

In road structural layers, mixtures of crushed limestone with oil bitumen are used as a structural material (black crushed stone), or as a part of asphalt concrete organic-mineral mixtures. Since limestone deposits are located in a great number of regions, their increased use makes it possible to reduce transportation costs in the estimated road construction cost. In the meantime, it is necessary to conduct a study of the aging of bitumen-mineral mixtures during their preparation and use in road structures when using local limestone materials. This article presents the results of the studies, during which the effect of bitumen aging on some properties of bitumen-mineral mixtures was studied using a new method. The developed method for studying bitumen aging compares favorably with the already known methods and is protected by the Patent of the Russian Federation No. 2654954. Due to this method, it becomes possible to study the effect of aging on the values of any indicator according to a single model – both complex (e.g. asphalt concrete) and simple systems (crushed stone-bitumen, sand-bitumen, etc.). This approach provides a more accurate prediction of the material behavior both during preparation and service in road structures. The execution of work involves the preliminary establishment of the optimal bitumen and crushed stone ratio, at which the highest average density and ultimate compressive strength at +20 °C is provided. Laboratory testing of samples indicated the dynamic pattern of the value of the aging coefficient and the aging rate in terms of the ultimate compressive strength at +50 °C and the elastic modulus.
Disposal of fly ash in the production of ash-concrete within the coal-watercoal cluster
Authors: Zommer T.V. , Tkach E.V. , Chernyshev S.N. , Zommer V.L.
Published: May 2021

Technologies for the disposal of industrial waste in the production of building materials are becoming particularly relevant in connection with the global trend of systematic reduction of the negative anthropogenic impact on the environment. Therefore, one of the goals of the pilot project of the innovative coal-watercoal cluster of housing and communal services is the utilization of ash waste from the combustion of coal-water fuel suspension in the production of building materials. The methodology of ash waste disposal consists in the modification of Portland cement with fine fly ash additives in the production of heavy concrete. As a result of the experiments, the authors proposed a recipe for a concrete mixture with ash waste additives. Tests of control samples of concrete and proposed samples of ash concrete with the addition of ash from the combustion of coal-water slurry were carried out. The brand of the proposed ash concrete in terms of compressive strength, corresponding to the design brand, is determined. Thus, we save the consumption of Portland cement as a binder, which is the most expensive component of concrete. At the same time, we dispose of man-made waste as a safe additive in the production of concrete with specified performance characteristics. The result obtained with the utilization of ash waste as an effective and safe aggregate for heavy concrete can be used in the implementation of a pilot project of an innovative coal-watercoal cluster of housing and communal services. Ash concrete with the addition of ash from the combustion of coal-water slurry can be recommended for use in industrial and civil construction.
Electromagnetic characteristics of biosilica from rice husk
Authors: Buz’ko Vladimir , Shamray Igor , Goryachko Alexander , Udodov Sergei , Abashin Anatoly
Published: May 2021

Rice husk, being a widely available natural plant renewable agricultural resource, can be transformed into effective reinforcing fillers of special concrete and gypsum building materials. The samples of silica from rice husks were synthesized by thermal oxidative pyrolysis and their electromagnetic and microstructural characteristics were investigated. It was found that the rice husk itself is practically EM-wave transparent material in the frequency range of 0.1-7 GHz, while the products of its thermal oxidative pyrolysis have different microwave absorbing properties, depending on the amount of oxidizing agent used. The X-ray powder diffraction data showed the predominant presence of amorphous silica in the samples of rice husk ash with a small amount of α-quartz, α-cristobalite and α-tridymite. At a pyrolysis reaction temperature of rice husk of about 560 ± 20°C, the resulting product, in addition to amorphous silica and crystalline phases of silicon dioxide, contains traces of graphite particles, which leads to a sharp increase in dielectric characteristics and effective microwave absorption. When the temperature of the pyrolysis reaction of rice husk rises above 700°C the EM-wave absorption of such materials decreases. Thus, on the basis of the experiments carried out, the optimal ratios of rice husk and the used oxidizer of ammonium nitrate were revealed to obtain environmentally friendly ecological low-cost powder nanostructured biosilica additives for concrete and gypsum building compositions with increased effective radio absorption in the frequency range of the electromagnetic field above 1 GHz.
Highly Efficient Glass Ceramic Thermal Insulation
Authors: Vedyakov Ivan , Vaskalov Vladimir , Maliavski Nikolai , Vedyakov Mikhail
Published: May 2021

Alkali-silicate thermal insulation materials (foam silicates) belong to the group of mineral heat insulators. Their main disadvantage is insufficient water resistance, to increase which special water-strengthening additives are introduced into materials. The aim of this work was to obtain and study foam silicates in granular (FGCG) and slab (FGCS) forms using a new production technology characterized by a simple one-stage technological scheme. Natural or technogenic amorphous silica, glassy sodium silicate (with the addition of carbonate or hydroxide) and a carbon-containing foaming agent, were used as the raw materials. Some part of the silica component was included in the binder solution, which made it possible to increase the silicate modulus in the final product to 5-10. This factor together with rather high Al2O3 concentration in the silica raw, made it possible to obtain foamed materials of very high water resistance. Another feature of the applied technology was a high foaming temperature (750–900°C). This factor makes a significant contribution to improving the water resistance of foam silicates, and significantly reducing their thermal conductivity and water absorption. As a result, FGCG was obtained with a bulk density of 170-440 kg/m3 (for FGCS – 300-400 kg/m3), a compressive strength in a cylinder of 0.5-6.3 MPa, a thermal conductivity of 0.046-0.084 W/(m·K) and a water absorption of 7.8-13.5% by volume. Mass loss of the specimens in boiling water was 0.12-0.33%, which puts obtained foamed materials on a par with most waterproof foam silicates being produced today.
Modern systems for monitoring the stress-strain state of hazardous power generating facilities
Authors: Zemlyansky Anatoly , Zhukov Alexander , Bulavina Daria
Published: May 2021

The paper considers the issue of effectively increasing the level of operational reliability of power generating nuclear and hydraulic facilities. Over the past 20 years, the number of accidents at these facilities has been growing. There are many factors affecting the collapse of structures, but, according to the authors, the lack of a monitoring system capable of fully assessing not only the stress-strain state, but also the so- called “residual” stresses of the material is the dominant direction of research. The same question is raised at the state level, as evidenced by the requirements of the STO, GOST and Federal laws, to which the authors refer below. The legislative prerequisites (requirements) for the creation of an improved system for monitoring critical structures, corresponding to the development trends of the construction industry, as well as the modernization of the existing fund are listed. The drawbacks and advantages of existing monitoring systems (strain gauge, string, fiber-optic sensors and acoustic emission systems) are analyzed in detail, and the general lack of the possibility of measuring, evaluating "residual" stresses in the material of structures is noted. A fundamentally new system for monitoring the stress-strain state of building structures and power equipment is proposed, which is based on the Foerster effect, a comparison is made with the existing systems described above. The main features and capabilities of the method are noted and options for use at highly important facilities are proposed.
Visualization and diagnostics of reliability of the object with changing the functioning conditions
Authors: Gvozdev Evgeny
Published: May 2021

The object of the scientific research is buildings (structures), which requiring the determination of a reliability indicator for their further operation in new operating conditions, the determination of additional loads in the form of (explosions, fires, vibration processes). The solution to such problems is relevant for buildings (structures), which are acquired (leased) by the owner, for their further operation in the new conditions of the technological process associated with the handling, storage, processing and production of fire and explosion hazardous substances (materials). It is important to determine the readiness of buildings (structures) for operation in the new conditions of functioning of the technological process of production, it is proposed to use deterministic, statistical and probabilistic approaches. It is proposed to use a simplified assessment of the safety margin of a building (structure) by yield strengths (for steel elements) and strength (for base materials, load-bearing walls, partitions and ceilings) corresponding to the maximum allowable values for their destruction. The innovative approach is described that allows us to solve the problems of assessing the strength reliability of structural elements of buildings (structures) to obtain guaranteed characteristics of a given margin of safety, its resistance to possible realized effects (explosions, fires, vibration processes)
Problems of thermal protection of two-layer external walls with hinged facade systems
Authors: Ibe Ekaterina , Shibaeva Galina , Mironov Svyatoslav , Litvin Danil
Published: May 2021

Currently, in the Republic of Khakassia, much attention is paid to research aimed at reducing air pollution due to fuel combustion. In this aspect, the issue of increasing the energy efficiency of buildings is relevant. The use of ventilated facade systems with an air gap makes it possible to improve the energy efficiency class of buildings and modernize the facades. However, these facade systems have weak points that require detailed and high-quality study. Often, design solutions are used that are used in warm climates without taking into account the peculiarities of a cold climate - frequent changes in temperature, humidity, wind loads, and other influences, which can lead to negative manifestations. Facade systems with a ventilated air gap must provide the ability to monitor the operability of all system elements and, if necessary, carry out repair and reconstruction work with minimal operating costs. The article presents an analysis of the thermal properties of an external fence using a hinged facade structure. The influence of installation defects and heat-conducting inclusions on the heat-shielding properties of the building envelope is shown. It was determined that during operation the moisture-windproof membrane loses its vapor-permeable properties.
Anchorage strength and ductility in shear tests
Authors: Shuvalov Aleksandr , Gorbunov Igor , Kovalev Mikhail
Published: May 2021

Article shows shear tests results for anchorage using bent foundation bolts 16, 24 and 36 mm in diameter and torque-controlled undercut anchors 12, 16 and 20 mm in diameter. Load-displacement diagrams were acquired for shear loads in static and dynamic cyclic tests in uncracked and cracked concrete. Cyclic loading pattern simulated seismic loads on anchors. Shear loading tests allowed to estimate influence of cracks and cyclic loading on strength and ductility of anchorage.
Experimental and theoretical studies of pumps of irrigation pumping stations
Authors: Glovatskiy Oleg , Ergashev Rustam , Rashidov Jaloliddin , Nasyrova Naira , Kholbutaev Boybek
Published: May 2021

The article presents the results of a study of the wear of individual pump elements, a decrease in their efficiency and significant losses. The nonidentical operation of the extreme and middle pumps was established. The uneven approach of water to the extreme units created reverse flows of water in the suction pipes, work with vibrations of modes close to cavitation. The modernization of the pumps improved the cavitation characteristics due to the elimination of the cavitation center at the impeller inlet in the area of the driven disk, which increased the reliability and durability of the pump. Diagnostics of irrigation pumps made it possible to substantiate proposals for the modernization of their main units and operating modes. The distribution of pumps according to the general level of vibration is shown, indicating the direction at which the maximum value of vibration displacement was recorded and the results of a comparative measurement of the vibration of the units of the pumping station-1 of the Karshi Main Channel (KMC).Studies of the pumps of large irrigation pumping stations have shown a reduction in vibration and an improvement in basic operating parameters. With the participation of the authors, new complex methods of operation are being developed, which allow increasing its reliability by predicting the technical condition.
Coastal and deep deformations of the riverbed in the area of a damless water intake
Authors: Bazarov Dilshod , Markova Irina , Khidirov Sanatjon , Vokhidov Oybek , Uljaev Farokhiddin , Raimova Ikboloy
Published: May 2021

The paper analyzes the dynamics of planned and deep deformations on the section of the Amudarya River in the area of the damless water intake in the main structure of the Karshi Main Canal-KMC. The results of field studies of the state of the canal situation of the Amudarya River at the site of a damless water intake are studied. The course of riverbed processes in the riverbed is studied. Recommendations for improving water intake conditions have been developed. According to the results of the field survey and the study of the head section of the supply canal, the state of the Amudarya riverbed in the water intake zone was assessed. The results of surveys of the hydraulic and pumping modes of sediments of the Amudarya River in the area of the damless water intake are analyzed and summarized. The results of field studies of the canal situation of the Amudarya River in the water intake area in the Amudarya River KMC in the area of the Karshi head water intake are studied. The riverbed situation is not characterized by constant hydraulic characteristics over time for the same water flow rate, i.e. with the same water horizon marks, the flow rates may differ from each other by about half, and with the same flow rates, the horizon marks may vary up to ± 0.6 m. This is explained by the extreme instability and high mobility of the canal, and large deformations of the canal occur in a short time. The hydraulic regime of the river is characterized by a significant redistribution of speeds, depth and width of the flow. The range of their changes is within: Maximum speed >Vmax =2…5 m/s; average speed Vav = 0.5…2.5 m/s; depth H max = 4…14 m, Hav = 1…5 m; width B = 300…2000 m; slope i = 0.00016…0.0003. It is established that the characteristic feature of the river is that at a constant flow can have different average velocities depth and width, for example, when Qw = 1000 m3/s, respectively, v = 0.6…1.7m/s, B = 180…1030m, Hav = 1.1…4.3m.
Analysis of the application efficiency of the slab-pile foundation using the example of a two-layer base
Authors: Chunyuk Dmitry , Selviyan Serafima , Selviyan Artem
Published: May 2021

The purpose of this work was to determine the increase of the limit load when resting the foundation slab on the ground at a different pitch of piles and their different length. The main task is to calculate the combined pile-slab foundation. The hypothesis was that when the foundation slab in the work, the bearing capacity of the entire structure increases. This foundation was calculated using the Plaxis 3D design software complex. In this article, we have determined the value by which the ultimate load on the combined pile-slab foundation increases when the slab rests on soil.
Regulation of the flow in the area of the damless water intake
Authors: Bazarov Dilshod , Norkulov Bekhzod , Vokhidov Oybek , Artikbekova Fotima , Shodiev Bobur , Raimova Ikboloy
Published: May 2021

The article discusses the results of numerical studies of the flow of the Amudarya river above the point of the damless water intake to the head structure of the damless water intake to the Karshi Main Canal-KMC. The system of two-dimensional equations of hydrodynamics-Saint-Venant is used as the basis of the mathematical model. In this work, a series of calculations of the field of currents in the river channel during low-water periods is carried out. Below are the main research results and proposals for ensuring the stable operation of the damless water intake in low-water conditions. The applicability of a numerical model composed of the equations of shallow water -the vector equation for the conservation of momentum and the scalar equation for the conservation of mass, has been proved, when describing a flow with the presence of circulation zones, which is typical when the water flow is constrained by blind dams. In this case, the solution pulsates around a certain average value, and the average length of the circulation zone behind the sudden expansion of the open flow is in good agreement with laboratory experiments. Numerical studies have shown that the device of a jet-guiding dam 150 m above the water intake gate in the CMC is more effective than when the dam is located 250 m above. In essence, dam № 2 with a length of 65 m does not affect the conditions at the water intake in the KMC at all, and dam № 2 with a length of 120 m is almost equivalent in its impact on the flow to dam №1 with a length of 50 m. Analysis of the results shows that the placement of an additional threshold in the Amudarya river bed improves the situation by raising the water level at the water intake. The threshold is flooded even at low water levels, which reduces the speed load on its body. At the same time, the threshold is located directly at the beginning of the channel, in part to protect the intake from incoming sediment, and high enough speed water glistening over the threshold in line, ensure the transit of sediment that can reduce enters the intake. Such measures will reduce the turbidity of water entering the channel. This, in turn, reduces the intensity of the silting process.
Stability of fire barriers in tank farms in case of destruction of vertical tanks
Authors: Korolchenko Dimitry , Halloul Younes
Published: May 2021

The issue of raising the level of safety of people, lands and property from potential threats in emergency situations in oil and gas storage and processing sites is particular concern to all levels of authority in countries, whether they are legal or executive authority.

Study of the statistical data of incidents and fires at these equipment showed that the most negative effects for the damage to the company’s personnel, the population and the environment occurred during the quasi-instantaneous destruction of the vertical steel tank. The distinguishing features of such an accident are the complete loss of the integrity of the vertical oil tank hull and the release of all the liquid stored in the tank in the form of a powerful flow (breakout wave), which has a great destructive power, to the adjacent territory within a short term of time.

The most important measures to reduce oil and petroleum products leakage in tank farms are reinforced earth dams and closed walls made of materials that are vulnerable to heat (important in the case of fire), Which led to many unsolvable cases. Recently, vertical steel tank with double walls of the “glass in a glass “type have been used in some oil tanks, in practice, they have not found wide application, which is due, first of all, it needs to allocate a significant territory for their arrangement, and its high cost.
Experience of determining the parameters of the elastoviscoplastic soil model
Authors: Ter-Martirosyan Armen , Manukyan Artur , Ermoshina Lyubov
Published: May 2021

Rheological studies of soils were carried out by S.S. Vyalov, M.N. Gol’dshtejn, N.N. Maslov, G.I. Ter-Stepanyan, S.R. Meschyan, A.L. Gol’din, Z.G. Ter-Martirosyan and many others. On the basis of existing rheological soil models, a new universal rheological equation was proposed in Ter-Martirosyan’s dissertation, which allows describing kinematic shear, creep and stress relaxation at the same parameters. Experimental studies of the soil were carried out in a simple shear device in a kinematic loading mode at a shear displacement rate u̇= 0.05 mm/min and at two values of compaction loads (σ1 < σ2). Based on the results of the experimental studies, the parameters of the elastoviscoplastic model were determined and graphs of the dependence of shear stresses on time were plotted, which clearly show the high convergence of the experimental and theoretical curves.
Validation of the calculation of a wooden column with a support unit on glued steel plates
Authors: Rudnev Igor , Zhadanov Viktor , Garipov Vladimir
Published: May 2021

The article proposes a structural solution for the base of a wooden frame column on flat links glued in the support part of the column – steel plates welded to the base plate. The results of numerical studies of the column, taking into account the parameters of the adhesive connection of the plates with wood and the anisotropy of wood, are presented. The column model takes into account the geometric and physico-mechanical characteristics of wood, steel plate bonds and adhesive compound. The main results of numerical studies are verified with the results of the analytical calculation of the column performed by the method of initial parameters. A physical model with the proposed structural solution of the column base was made and tested. The numerical and analytical calculations of the column were validated, and the main conclusions of the experimental and theoretical study were presented.
Numerical and asymptotic flow stability analysis of vortex structures
Authors: Akhmetov Vadim
Published: May 2021

Stability problem of an axisymmetric swirling flow of a viscous incompressible fluid with respect to nonaxisymmetric perturbations is considered. The system of ordinary differential equations for the amplitude functions is solved numerically by the Runge-Kutta method and orthogonalization procedure. Solutions of equations for perturbations at the neighborhood of singular points are obtained by the Frobenius method. The maximum of amplification coefficients and phase velocities of five unstable modes are calculated.
Automated identification of construction works and structural elements at an early stage of investment and construction projects’ implementation
Authors: Ginzburg Alexander , Tyurin Ilya
Published: May 2021

The article discusses the issues of construction objects pricing in terms of the formation of certain types of costs and an analysis of their interrelationships based on the generated data bank of design and estimate documentation of implemented state investment construction projects. Special attention is paid to the research of the impact of changes in design solutions on the cost of construction. Approaches to the reorganization of the established design technology are proposed. These approaches use automated identification of construction work and structural elements based on the method for assigning criteria for the selection of building structures that are supposed to be erected around the technological space specified by the customer. The selection criteria established in this way assist designers in finding optimal design solutions for the subsequent development of working documentation.
Modeling of foundation slabs of buildings on complex foundations
Authors: Erokhin Sergey , Shashkin Sergey
Published: May 2021

The paper considers the problem of calculating the strength of foundation slabs under seismic and wind loads. As an example, a numerical model of a hotel building to be built on bulk islands is presented. The calculation of the foundation slab model is performed using the STARK ES software package. The results of the calculation are analyzed and recommendations for strengthening the foundation are given.
Interactive numerical model of hydrometeorologic factors in Kola Bay
Authors: Kantarzhi Izmail’ , Anshakov Aleksandr
Published: May 2021

The structure of the developed interactive model of wind waves and currents for the construction area in the Kola Bay, Barents Sea is considered. The interaction between three modules of the developed model which based on the SWAN, ARTEMIS and COASTOX models is shown. The interactive model can be applied to get the statistical characteristics of waves and currents. The article presents an overview of the results of applying a chain of numerical models to determine the wave loads on the structures of the projected Center for the Construction of Large-capacity Marine Structures in the Kola Bay.
Comparative statement analysis of span structures with a reinforced concrete and orthotropic plate under the exposure of solar radiation
Authors: Gridnev Sergey , Podlesnykh Igor , Rezunov Aleksandr , Mukhtarov Rinat
Published: May 2021

Carried out a comparative analysis especially the exposure to solar radiation on the stress-strain state (SSS) of span structures with orthotropic slabs of reinforced concrete. Determine the character limit of the temperature distribution in the elements of the two types of spans according to the results of field measurements. Conducted calculation of Stress-Strain State on specific cases of solar radiation with the use of the developed finite element (FE) models of two types of span structures in the platform LIRA SAPR. The results of SSS features obtained for a steel-reinforced concrete superstructure and a metal superstructure with an orthotropic slab are compared. It is shown that the uneven daytime change in the temperature field under the influence of solar radiation has a significantly different nature of effect on the stress-strain state of elements of metal and steel-reinforced concrete span structures.