bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of bentonite type and producing method on hydraulic conductivity of sand–bentonite mixture
Authors: Sakita Tomonori , Komine Hideo , Yamada Atsuo , Wang Hailong , Goto Shigeru
Published: November 2020

Sand-bentonite mixtures with bentonite content of 10-30% had been planned to handle low-level radioactive waste in Japan, because of its low permeability. Hydraulic conductivity of sand–bentonite mixture depends on the bentonite type, bentonite content, initial water content, and other factors. Given this background, falling head permeability tests were conducted on sand–bentonite mixture by varying the compaction energy for specimen preparation, initial water content (10–20%), and bentonite content (15– 30%). For these tests, the hydraulic gradient of 25-500 was set. Consequently, the hydraulic conductivities were 10-8 – 10-13 m/s for all tested conditions. Correlation between the hydraulic conductivity and the effective montmorillonite dry density (montmorillonite mass divided by the sum of montmorillonite, air, water volume), which is often used to correlate the hydraulic conductivity of bentonite, was found. Correlation was also found between the hydraulic conductivity and a new index designated as the effective montmorillonite wet density (sum of montmorillonite and water mass / sum of montmorillonite, air, water volume). Effective montmorillonite wet density reveals differences in the specimen structural distribution through consideration of the initial water content.
Influence of the capillary pipe geometry on the energy efficiency of household refrigerator
Authors: Hristov Hristo , Simitchiev Apostol , Stoeva Donka
Published: November 2020

The energy efficiency of household refrigerating appliances was measured according to EN TSO15502. A Liebherr TKP 1650 built-in Domestic refrigerator is used to determine the influence of the capillary pipe geometry. The temperatures at the injection site of the refrigerant, the inlet and outlet of the evaporator receiver were measured. The obtained results show that there is no universal optimal geometry of the capillary pipe. There is no element of the refrigeration cycle whose change has no effect on the refrigerant flow rate passing through the capillary pipe. A change in the geometry of capillary pipe affects all other components of the refrigeration cycle and can greatly improve or impair the efficiency of the refrigerator. The potential for switching from one to two different geometries of the capillary pipe is approximately 8% improvement in energy consumption. Possible implementation should take into account the potential savings - 8% and the life cycle of the particular appliance (- 15 years). For the particular measured device, the consumption per year is about 75kWh, which should take into account that the device itself has a low volume and low energy consumption.
Experimental investigation of acid mining water
Authors: Pushkarov Martin , Velichkova Rositsa
Published: November 2020

In presented work is made an experimental study for purification of mining water. Depending on the specific requirements, the required methodology is used. It is made an analysis of the obtain results. Experimental studies to determine the levels of purification of impurities monitored in the treated mine water depending on the chosen method for their treatment were conducted on the basis of the compared results for the content of monitored pollutants - mainly insoluble substances, iron, manganese and metal cations.
Numerical Simulation of Reoxidation Processes
Authors: Bruna Marek , Galčík Marek
Published: November 2020

Reoxidation is one of the main problem accompanying the aluminium alloy casting process. The oxide layer created on the melt surface during reoxidation is entrained into the bulk of liquid metal and “bifilms” are created. Bifilms have negative impact on cast quality and internal homogenity of final casting. Paper aim is to clarify the reoxidation phenomenon by visualization with the aid of ProCAST numerical simulation software. Experiemtnal work deals with the design of several types of gating systems (non pressurized and naturally pressurized) with vortex elements in order to determine how these elements affect the reoxidation processes. Achieved results clearly confirmed the positive effect of the naturally pressurized gating system with vortex elements. The evaluation focuses mainly on melt velocity and amount of oxides created in gating system and in mold cavity.
Evaluation of the Characteristics of the Control Valves
Authors: Jablonská Jana , Kozubková Milada
Published: November 2020

When designing pipeline networks, the knowledge of loss coefficient respectively resistance coefficient when flowing through various types of fluids through hydraulic elements, e.g. control valves, which are often used in the engineering and energy industry. Their specification is performed mainly experimentally. However, there are applications where the experimental approach of their determination is unrealistic and then mathematical methods can be considered. The article presents a methodology for determining the static characteristics of the DN25 control valve for different opening. The measurement of the characteristics was performed with an incompressible flowing medium - water and with a compressible flowing medium - air. Subsequently, a comparison of measurement and evaluation of loss and flow coefficients was performed. The measured values will be further used to verify the results of modelling and to precisely define mathematical models, so that the models can be subsequently used at vapour flow, where the experimental method of determination is difficult. Frequent applications are found in the flow of saturated and superheated vapour through control valves.
Measurement on Axial Reaction Turbine Stage
Authors: Klimko Marek , Žitek Pavel , Lenhard Richard
Published: November 2020

This article describes a measuring methods and evaluating measured data on a single-stage axial turbine with reaction (~ 50 %). One turbine operating mode was selected, in which the traversing behind the nozzle and bucket with two 5-hole pneumatic probes took place. The results are distributions of flow angles, reactions, or losses distribution/efficiencies along the blades.
Bat parasites (Acari, Anoplura, Cestoda, Diptera, Hemiptera, Nematoda, Siphonaptera, Trematoda) in France (1762–2018): a literature review and contribution to a checklist
Authors: Léger Clément
Published: November 2020

This paper is a bibliographical survey of records of bat parasites in France (including Corsica) between 1762 and 2018. In total, 237 scientific publications were analysed. They show that bats are infected with a large diversity of endoparasites and ectoparasites. A total of 113 parasite taxa were identified from 27 host species; in addition, six bats were not identified to the species-level. The helminth fauna of bats comprises three species of Cestoda, 15 of Trematoda, and 13 of Nematoda. Acari parasites include 53 species (in addition to 22 invalid species). Finally, insect parasites comprise 13 species of Diptera (bat flies), 12 of Siphonaptera (fleas), 3 of Hemiptera (bugs), and 1 Anoplura species. Bat taxa reported with parasites wereBarbastella barbastellus, Eptesicus serotinus, Hypsugo savii, Miniopterus schreibersii, Myotis bechsteinii, M. blythii, M. capaccinii, M. dasycneme, M. daubentonii, M. emarginatus, M. myotis, M. mystacinus, M. nattereri, M. punicus, Nyctalus lasiopterus, N. leisleri, N. noctula, Pipistrellus kuhlii, P. nathusii, P. pipistrellus, Plecotus auritus, P. austriacus, Rhinolophus euryale, R. ferrumequinum, R. hipposideros, R. mehelyi, Tadarida teniotis, Eptesicussp.,Myotissp.,Pipistrellussp.,Plecotussp.,Rhinolophussp. and the species complexPipistrellus pipistrellus/kuhlii/nathusii. As regardsE. nilssonii, Vespertilio murinus(Particoloured Bat), M. alcathoe, M. escalerai, P. macrobullarisandP. pygmaeus,no records were found. These published field data originated from 72 of the 96 departments in metropolitan France. The most commonly cited were Ardèche, Ariège, Bouches-du-Rhône, Haute-Savoie, Maine-et-Loire, Moselle, Meurthe-et-Moselle, Pyrénées-Orientales, Sarthe, Haute-Corse and Corse-du-Sud.
Mon école est dans la rue
Authors: Voltolini Rinaldo
Published: November 2020

Faisant partie des politiques gouvernementales de lutte contre l’exclusion sociale, l’école inclusive apparaît dans nos sociétés occidentales comme un dispositif institutionnel, forgé à coup de lois et de mesures administratives qui en découlent. Dans cet article nous proposons de faire l’analyse critique de la construction conceptuelle de ce modèle, tout comme des difficultés de son fonctionnement au quotidien. En présentant le cas d’une jeune fille psychotique qui a échoué à l’école jusqu’à s’en faire exclure définitivement, nous illustrerons certaines difficultés de l’école dite inclusive à tenir son projet d ‘école-pour-tous.

C’est dans l’alternance entre la rue et d’autres lieux d’accueil, que cette jeune fille suivie par son « accompagnant thérapeutique », a trouvé les conditions d ‘ apprentissage qu ‘ elle avait perdues à l ‘ école, une école qui s ‘ est montrée incapable de supporter le désarroi produit par sa présence. Occupée par une quête idéaliste, l ‘ école inclusive a oublié la différence entre une soi-disant institution bonne et une institution suffisamment bonne.
Un dispositif de médiation à l’école pour faire face au mutisme sélectif des enfants migrants
Authors: Carmo-Huerta Viviani , Debieux-Rosa Miriam
Published: November 2020

Cet article aura pour objectif de présenter un dispositif de médiation clinique en milieu scolaire créé pour faire face au nombre grandissant de demandes de prise en charge psychologique destinée aux enfants de migrants présentant une symptomatologie qui vient impacter leurs apprentissages scolaires, notamment le mutisme sélectif ou extra-familial. Ce dispositif est conçu comme un espace de métaphorisation, selon les mots d’Alice Cherki. À partir de la rencontre avec Asraf, un enfant de 7 ans, mutique depuis sa rentrée à l’école maternelle, les auteurs œuvrent pour la création de lieux ouverts à la pluralité des systèmes symboliques, des lieux capables de rompre le silence et de faciliter l’émergence de la parole et de la subjectivation.
Acceptability of endoscopic submucosal dissection for sessile serrated lesions: comparison with non-sessile serrated lesions
Authors: Kuroki Yuichiro , Endo Toshiyuki , Iwahashi Kenta , Miyao Naoki , Suzuki Reika , Asonuma Kunio , Yamamoto Yorimasa , Nagahama Masatsugu
Published: November 2020

Background and study aims Sessile serrated lesions (SSL) are major precursor lesions of serrated pathway cancers, and appropriate treatment may prevent interval colorectal cancer. Studies have reported the outcomes of endoscopic mucosal resection (EMR) for SSL; however, there are insufficient reports on endoscopic submucosal dissection (ESD). We examined the characteristics and outcomes of SSL and compared them to those of non-SSL in ESD.

Patients and methods We reviewed 370 consecutive cases in 322 patients who underwent colorectal ESD between January 2016 and March 2020 at our hospital. There were 267 0-IIa lesions that were stratified into 41 SSL and 226 non-SSL (intramucosal cancer, adenoma) cases. We used propensity matching to adjust for the variances in the factors affecting treatment between the SSL and non-SSL groups.

Results In the baseline cases, young women and proximal colon tumor location were significantly more common in the SSL group. There were no statistically significant differences between the SSL and non-SSL groups in terms of en bloc resection rate (97.6 % vs. 99.6 %; P = 0.28), R0 resection rate (92.7 % vs. 93.4 %; P = 0.74), perforation (0 % vs. 0.9 %; P > 0.99), and postoperative bleeding (2.4 % vs. 1.8 %; P = 0.56). Thirty-eight pairs were matched using propensity score, and the median dissection speed (12 vs. 7.7 cm2/h; P = 0.0095) was significantly faster in the SSL than in the non-SSL group.

Conclusions ESD for SSL was safely performed, and SSL was smoother to remove than non-SSL. ESD might be an acceptable endoscopic treatment option for SSL.
Current Recommendations on Optic Neuritis
Authors: Beisse Flemming , Beisse Christina
Published: November 2020

Background Optic neuritis is a special challenge to the ophthalmologist. It is a relatively frequent condition but difficult to seize morphologically. It has neurological implications and is subject matter of recent trials.

Methods Selective literature search including the authorsʼ professional experience.

Results Practical aids for the ophthalmological management of optic neuritis are derived from the best available evidence and the recent literature is discussed.

Conclusions The present paper provides evidence-based recommendations for a safe handling of optic neuritis as well as information on current issues.
A Modified VATS Procedure for Treating Adult Intralobar Pulmonary Sequestration
Authors: Zeng Bo , Zou Jianyong , Yang Weixiong , Liu Zhenguo , Xie Chunying , Cheng Chao
Published: November 2020

Video-assisted thoracoscopic surgery (VATS) makes it possible to treat intralobar sequestration (ILS) more minimally invasive compared with conventional open surgery. However, this procedure is challenging to expose and isolate the aberrant arteries of ILS and the risk of bleeding is high. Herein, we developed a modified VATS procedure in which the aberrant vessels are treated in the last step of lobectomy, rather than at the beginning. In this way, we can expose the aberrant vessels easier and reduce the risk of massive blood loss, also simplifying the surgical procedure.
Gut passage time and viability of seeds consumed by Australian marsupials
Authors: Beca Gabrielle , Palmer Bryony , Valentine Leonie E. , Erickson Todd E. , Hobbs Richard J.
Published: November 2020

Many Australian mammals consume seeds, but their role in seed dispersal has not been well explored. Here, we investigated the mean retention time and the postconsumption germination capacity of Australian seeds (Acacia acuminata, Dodonaea viscosa and Gastrolobium calycinum) likely to be consumed by quenda (Isoodon fusciventer) and woylies (Bettongia penicillata ogilbyi). Mean excretion times were 14h for quenda and 24h for woylies, but some seeds were retained in their digestive passages for up to 39.5 and 55.5h, respectively. Viable seeds of all plant species were retrieved from both species’ scats and only G. calycinum seeds ingested by quenda had a significantly higher germination percentage (62%) than control seeds (34%). Our results show that viable seeds are deposited in the scats of quenda and woylies, indicating that these species may play a role in seed dispersal.
Host-associated microbiota of yellow stingrays (Urobatis jamaicensis) is shaped by their environment and life history
Authors: Pinnell Lee J. , Oliaro Francis J. , Van Bonn William
Published: November 2020

Insights gained from the unique scientific opportunities presented by public zoos and aquaria can help inform conservation and management decisions for wild populations and provide a rationale for decisions on exhibit design and maintenance for managed populations. This study has shown the diversity and composition of the microbiota associated with three different populations of yellow stingrays (Urobatis jamaicensis); wild rays (W), aquarium-housed rays originally caught in the wild (WC), and aquarium-born rays (AB). The microbial communities of wild rays were more diverse and had a different structure than did both WC and AB ray populations. Importantly, differences also existed between the two populations of aquarium-housed rays. There were significantly lower abundances of Bacteroidetes in skin-associated communities from WC rays v. AB rays, whereas there were significantly higher abundances of Vibrionaceae in cloaca-associated communities of WC rays v. those born in the aquarium. Additionally, the diversity of cloacal microbial communities was significantly lower in WC rays than aquarium-born rays. Findings from this study have demonstrated that a move from a wild to managed environment alters the host–microbe relationship in yellow stingrays and have lent support towards the refinement of aquarium disinfection strategies and expansion of cooperative breeding programs in the zoo and aquarium community.
Sugar production dynamics in Zimbabwe: an analysis of contract farming at Hippo Valley
Authors: Mazwi Freedom
Published: November 2020

This article examines the nature of contractual relations between sugar outgrowers (contract farmers) and Tongaat Hulett Zimbabwe (THZ). Drawing from a research study conducted at Hippo Valley Estate, using a mixed-methods approach, findings reveal asymmetrical power relations in favour of THZ as reflected by its domination in price determination, monopsony control and risk sharing. Despite radicalisation and attempts by the state to curb the powers of international finance, the article argues that monopoly capital continues to wield significant control in Zimbabwe, leading to growing farmer indebtedness. Thus, the state–capital alliance presents a stumbling block for accumulation by sugar outgrowers.
The least informative distribution and correlation coefficient of measurement results
Authors: Mana G , Pizzocaro M
Published: November 2020

Correlations play a significant role in data analysis and the evaluation and expression of the uncertainty, yet estimating them is often difficult. This paper provides examples of how to infer the measurand value, given only the uncertainties and correlation ranges of the measurement results. The least informative data-distribution is not Gaussian, but the marginal distributions are. Explicit results are given in the case of a data pair, where the inferred correlation coefficient is the midpoint of the given range.
Data Security inside Optical Communication Networks through Encoding and Steganography
Authors: Salim Wadah Hatim , Mahdi Bushra R. , Dhaigham Ayad A.
Published: November 2020

This paper provides securing flowing of data in optical systems through encoding and steganography. Encoding (Cryptography) and steganography are major elements for secure the data. Suggested communication system aids for transporting huge volumes of information of quickly and reliably. This communication system has previously displayed unrivalled characteristics of most secure. Secure connection requires the integration of cryptography and steganography, so it is very difficult to penetrate it. The system program uses cryptography and steganography to merge any type from files and encrypted text that are effectually hidden for human eye with a carrier image. Also, the extra purpose from this paper is to procure the threshold losses of the optical system and introduce a new approach to create an ideal system that can effectively secrete a message that includes important information, if and only if the optical cable losses increase by its threshold magnitude.
Decadal Surface Temperature Trends in Iraq using NOAA/ESRL Gridded High Resolution Data
Authors: Majeed Husam T. , Al-Zuhairi Munya F. , Mahmood Dalia A.
Published: November 2020

Global warming has major impacts on world environment and human activities and it has been of increasing concern by scientific community, governmental agencies, and public. Iraq as one of the Middle East countries is vulnerable to global warming. Recent research works indicated that Iraq is facing an increasing heat waves and more aridity. The aim of this work is to analyze long-term temperature (1900-2017) to determine the warming and cooling phases at Mosul (north), Baghdad (center), Rutba (desert), and Basra (south). Gridded high-resolution monthly means of temperature were obtained from NOAA/ESRL. 30 years (1981-2010) available data from Iraqi Meteorological Organization were used to verify The NOAA/ESRL data. Results of comparisons of the two sets of data indicated that they are highly correlated. Time series analysis showed that the most effect of global warming on Iraq occurred on the decades of 2000’s and 2010’s during summer months (Jun, July, and Aug). The most affected cities were Baghdad and Basra. The less affected city was Rutba. Rutba is less populated town located on the desert near the borders with Jordan. Analysis of temperature decadal anomalies showed that from 1900’s to 1980’s temperature was cooling with anomalies between 0 and -0.5°C (except during 1960’s anomalies were less than +0.25). The results also indicated that during the last three decades (1990’s to 2010’s) temperature was warming and the highest warming (about +1.5 °C) occurred during last eight years (2010-2017) in all four cities.
Development of a display system for visualization in medical Applications
Authors: Almgoter Halah Basim , Al-Dahan Ziad Tarik
Published: November 2020

Imaging capabilities have been enhanced by scan modality. A review and comparison of some of the most effective open source libraries and medical application development has been implemented. A system composed of Ultrasound-Diagnostic-Machine-CMS600B2, a core i7-9750h Intel laptop processor, an easy-to-use capture tool for converting ultrasound analog images to digital images stored in a laptop and VR receiver to imagine a full organ. The understanding of 3D medical information earned very little consideration when it was intended to look at the ability of investigators to solve problems in 3D space. The aim of this research is to develop powerful computational techniques for integrating, interpreting and analyzing images for creative use in clinical practice. It’s turning into extra common to speak regarding 3D, 4D images formed by modern imaging techniques. The potential will be demonstrated by the evolution of medical imaging and VR systems that led to this system.
Sunflower seed oil effect on some physiological cases of adult chickens. Running Title: Gamma ray effects as oxidant stress on several physiological cases
Authors: Al-Dulamey Qusay Kh. , Oraibi Afrah Hassoon , Al-Salihi Abdalrahman
Published: November 2020

This study aims to evaluate the effects of gamma-ray oxidation stress (ionization of biological cell as sperm) on the adult chicken reproductive system. In this research, we used cocks chicken at 36-54 weeks of age and find the importance of semen volume in (ml / brid / ejac). Concentration in (Million cells / ml.) and total sperm (Million cells / ejaculation). The value of semen volume, semen concentration and total sperm significantly increased with increased age of cock chicken but not at all ages, only at limited ages considered as control group. These values were found at irradiation with low dose rate (low intensity) of gamma ray (33, 42, and 75 mGy/h) which is a chronic dose rate (long time of irradiation) at 8 h/day for 40 days, which was significant decrease with increase low dose rate gradually. The semen volume decrease ratio with irradiation doses of approximately 5-14% and with semen concentration of approximately 5-12% for three chronic low doses relative to the control group for each cock generation. The average value of both groups showed a substantial decrease in all parameters with increased gamma radiation dose levels. The current study also aimed to identify the problems that may arise from exposure to a slow and equal dose of radiation on certain sperm parameters for a relatively long period of time and to compare them with the findings of previous work on the same mechanism and Use of sunflower seed oil as a protective and protective material against oxidative stresses resulting from radiation exposure and work Reducing its percentage, especially on certain sperm parameters in male chickens.
Ultrasound-assisted adsorption of pharmaceuticals onto clay decorated carbon Nano composites as a novel adsorbent: as a Applicable for environmental studies
Authors: Aljeboree Aseel M , Alshirifi Abass Noor , Alkaim Ayad F.
Published: November 2020

Pharmaceutical pollutants substantially affect the environment; thus, their treatments have been the focus of many studies. Pharmaceuticals, which are frequently detected in natural and wastewater bodies as well as drinking water have attracted considerable attention, because they do not readily biodegrade and may persist and remain toxic. As a result, pharmaceutical residues pose on-going and potential health and environmental risks. To tackle these emerging contaminants using one type of Carbone source (CNT) has been widely used as highly effective adsorbent for antibiotics because of its large specific surface area, high porosity, and favorable pore size distribution. In this study, the adsorption performance of CNT towards major types of antibiotics such as Phenylephrine hydrochloride drug. The removal present increase with increase amount of adsorbent but decrease with increase initial drug concentration, and contact time.
Synoptic assessment of coastal total alkalinity through community science
Authors: Rheuban J E , Gassett P R , McCorkle D C , Hunt C W , Liebman M , Bastidas C , O’Brien-Clayton K , Pimenta A R , Silva E , Vlahos P , Woosley R J , Ries J , Liberti C M , Grear J , Salisbury J , Brady D C , Guay K , LaVigne M , Strong A L , Stancioff E , Turner E
Published: November 2020

Comprehensive sampling of the carbonate system in estuaries and coastal waters can be difficult and expensive because of the complex and heterogeneous nature of near-shore environments. We show that sample collection by community science programs is a viable strategy for expanding estuarine carbonate system monitoring and prioritizing regions for more targeted assessment. ‘Shell Day’ was a single-day regional water monitoring event coordinating coastal carbonate chemistry observations by 59 community science programs and seven research institutions in the northeastern United States, in which 410 total alkalinity (TA) samples from 86 stations were collected. Field replicates collected at both low and high tides had a mean standard deviation between replicates of 3.6 ± 0.3 µmol kg−1 (σ
mean ± SE, n = 145) or 0.20 ± 0.02%. This level of precision demonstrates that with adequate protocols for sample collection, handling, storage, and analysis, community science programs are able to collect TA samples leading to high-quality analyses and data. Despite correlations between salinity, temperature, and TA observed at multiple spatial scales, empirical predictions of TA had relatively high root mean square error >48 µmol kg−1. Additionally, ten stations displayed tidal variability in TA that was not likely driven by low TA freshwater inputs. As such, TA cannot be predicted accurately from salinity using a single relationship across the northeastern US region, though predictions may be viable at more localized scales where consistent freshwater and seawater endmembers can be defined. There was a high degree of geographic heterogeneity in both mean and tidal variability in TA, and this single-day snapshot sampling identified three patterns driving variation in TA, with certain locations exhibiting increased risk of acidification. The success of Shell Day implies that similar community science based events could be conducted in other regions to not only expand understanding of the coastal carbonate system, but also provide a way to inventory monitoring assets, build partnerships with stakeholders, and expand education and outreach to a broader constituency.
Continuous coexistency preservers on effect algebras
*
Authors: Mori Michiya , Šemrl Peter
Published: November 2020

Let H be a finite-dimensional Hilbert space, dim H ⩾ 2. We prove that every continuous coexistency preserving map on the effect algebra E(H) is either a standard automorphism of E(H), or a standard automorphism of E(H) composed with the orthocomplementation. We present examples showing the optimality of the result.
Statistical assessment of damnification risk due to inconformity of paint coating quality
Authors: Loganina V , Uchaeva T
Published: November 2020

Provides information about the values of the risk of paint and coatings mismatch with the requirements of regulatory documentation. Risk considered as the probability of an adverse event. The probability of destruction of the adhesion strength of paintwork coatings of building products and structures is considered. The probability of destruction of the paintwork was calculated taking into account the Laplace function. It is established that the probability of paint coating adhesive destruction is minimal. The risk was calculated as expected damage. The values of risk as expected damage because of coating adhesive destruction are from 0.068 to 11.18 rubles per square meter depending on the coating type.
Acoustic method for measurement of crack width in concrete
Authors: Perfilov V A
Published: November 2020

The article presents the results of research and experimental studies aimed at measurement of crack width in concrete under the impact of mechanical loading. During the research, the author simultaneously measured load, deformation, crack width, acoustic emission gross counting by tensiometric and acoustic methods and obtained full diagrams of concrete deformation. The experiments resulted in regression equations and their combined diagrams showing relation between acoustic emission gross counting and mechanical loading level. The author identified the parameters of macro-crack initiation and their width in lightweight concrete depending on the value of the applied load. The conducted experiments and statistic processing of the data produced the correlation between the crack width and acoustic emission gross counting.
Production process of dolomite-based facing building materials
Authors: Khuziahmetov R Kh , Ibragimov R A , Khuziahmetova R N
Published: November 2020

The paper presents comparative data on the strengths and weaknesses of glass-magnesite sheets (GMS) and glass dolomite sheets (GDS). It is shown that, over time, the GDS samples change their geometric dimensions more than their GMS counterparts. As established, this is primarily due to the low MgO activity of caustic dolomite (CD), sub-optimal composition of the raw materials, and the large size of particles. The paper proposes a method for activating caustic dolomite by ultrafine grinding in a device with an external electromagnetic layer (vortex-layer device, VLD). A formulation of laboratory GDS samples based on activated caustic dolomite has been developed. It has been found that the strength of the obtained GDS samples is much higher (up to 4-8 MPa). Furthermore, they do not change their geometric shapes (no deformation of samples is observed during the warranty period). Also developed is a production process scheme for GDS samples based on activated CD and a three-dimensional production model.
Piezooptical properties of ice
Authors: Zhurbenko A O , Likhachev A V , Tabanykhova M V
Published: November 2020

In connection with the use of ice as a building material, it is interesting to study its strength characteristics. To increase the strength of ice, the ice matrix was reinforced by adding various materials of natural origin. The greatest significance in this study is the assessment of the stress-strain state of ice composites. The possibility of the photoelasticity method applimentation to obtain stress fields in ice composites was considered. Due to the lack of data about the piezo-optical properties of ice, we performed numerous studies in this direction. As a result of research, it was found that it is not possible to quantify the piezo-optical properties of ice, because ice has a low optical sensitivity, high brittleness, and the ability to melt at room temperature. It is possible to qualitatively characterize stress fields, identify stress concentrators, and describe the effect of reinforcing materials on the stress state of the ice matrix using the photoelasticity method. The use of ice-composite materials in the Arctic is a promising direction.
Solving the contact problem when strengthening the slab with a beam using discontinuous functions
Authors: Kobelev E A , Lukashevich N K
Published: November 2020

Problems of contact interaction of structures and their parts have a wide range of applications in construction. In particular, this problem arises during the reconstruction of existing buildings, when strengthen of floor slabs is required to increase their bearing capacity. In this case, the contact of the slab with the strengthening beams occurs along a continuous line of a given shape with a contact zone unknown in advance. In this paper, with the aim of constructing high-accuracy numerical-analytical solutions for the contact problem while keeping some series members, the mathematical apparatus of the theory of generalized functions is widely used. To solve the structurally nonlinear problem of strengthening the floor slab with an elastic beam, a step-by-step loading method is used. At each step, the deflection functions, the length of the contact segment, the value of the reaction along the contact segment are determined and the working scheme of the plate-beam reinforcement system is specified from the minimum functional condition of the potential energy of the contacting elastic elements. Using the proposed numerical-analytical approach, we obtained and analyzed solutions to the problem of one-sided support of a slab to an elastic gain beam. Due to the twodimensional approximation of the function of a slab deflection by discontinuous functions, the proposed approach shows satisfactory convergence, stability and accuracy of the solution while keeping some terms of the series.
Investigation of the deformation of elastic rods under thermomechanical loading
Authors: Brzhanov R T , Baysarova G G
Published: November 2020

This article aims to provide information on ongoing research with coverage of preliminary results. Analysis of the state of the rods theory is one of the intensively developing parts of mechanics since the second half of the XIX-th century. Soviet scientists made a significant contribution to the development of rods theory and applied calculation methods. Based on these methods, a number of practically important problems have been solved. The works were mainly related to the theory of elastic rods. From the analysis of the work performed, we proposed a solution to the deformation of elastic rods under thermomechanical loading in a nonlinear formulation from the standpoint of modern systems of numerical analysis. The purpose of this article is to develop the methods for calculating nonlinear problems of the deformation of rods under thermomechanical loading using modern problemsolving systems. The solution of the nonlinear problem in the general setting is extremely hard. Therefore, it is necessary to develop a methodology that takes into account the features of deformation and will be available to specialists when designing the elements of engineering and building of rod structures.
The value of the intensity of wear to ensure the durability of multi-apartment housing in the renovation of residential areas
Authors: Khotamov A T
Published: November 2020

Most of the apartment houses belonging to several “generations”, which exist in different regions of the Republic, today have a different level of technical condition. The purpose of this study is to determine the process of wear and aging of building structures and buildings in multi – apartment buildings in General in order to clarify the durability of residential blocks for subsequent planning of their renovation. The results of the study show that the indicator of longevity of multi-family residential buildings in many cases depends on the quality of operation. The actual service life of certain parts of buildings, such as foundations, walls, and coverings, is also set, depending on the location in the region. Significant factors that negatively affect the durability of buildings, such as salinity of the soil, increase in the level of groundwater, are determined. In conclusion, it is noted that the results of this study are adapted to the effective use of the housing stock for sustainable development from the point of view of safety in the development of a phased renovation program for the future development of cities.
Selection of the optimal parameters of a reinforced concrete rectangular beam with single reinforcement
Authors: Kuznetsov V S , Shaposhnikova Yu A , Yandiev A A
Published: November 2020

The article is devoted to the problem of choosing the optimal parameters of reinforced concrete rectangular beams with single reinforcement. The analysis of the dependence of the cost of a single-span hinged-supported reinforced concrete beam on the selected parameters of its cross section under the action of a uniformly distributed load. The optimal range of cross-sectional parameters of reinforced concrete articulated beams (height, width, class of concrete and reinforcement, area and reinforcement pitch) was determined depending on the value of the uniformly distributed external load. Strength calculation of reinforced concrete beams is based on the traditional method given in the SR.63.13330.2018 “Concrete and reinforced concrete structures.” The cost of reinforced concrete beams was calculated under the influence of various uniformly distributed loads. The first option, where the width of the beams was constant and the section heights varied between 250 and 1000 mm. The second option, when the heights of the beams were taken equal, and the widths of the beams were in the range from 100 to 500 mm. The recommended height and width of the beam section for the specified value span in the investigated range of loads was set.
Method for calculating deflections of beams made of rubber concrete
Authors: Polikutin A E , Levchenko A V , Potapov Yu B
Published: November 2020

In many bending elements, the defining calculation for ensuring the normal operation of the structure is the calculation of deflections, it is this characteristic of the structure, in particular the beams, that determines the section dimensions of the element, to ensure the necessary rigidity of structures. In view of this, the use of many polymer concrete as a material for the manufacture of bending structures becomes impossible due to the high deformation-as a consequence of the low elastic modulus. Our proposed polymer concrete based on liquid rubber (rubcon) has high compressive and tensile strengths, while the elastic modulus corresponds to ordinary cement concrete class B25. The introduction of fiber filaments into the material structure slightly increases these characteristics, and the rubber concrete obtained in this way with fiber reinforcement is called fiber rubcon. In order to ensure the possibility of calculating by way of determining the deflections of rubcon structures with cracks, we apply the principle of strain averaging of V.I. Murashov, while the uneven distribution of strains in the rubcon was taken into account by the coefficient ψk, the polymer concrete work between cracks is taken into account by the coefficient ψs, which are determined similarly to V.I. Murashov, A.S. Zalesov methods.
Research of multiple metal rods joining node in spatial construction, using one welding connection
Authors: Alpatov V , Laguta I
Published: November 2020

Elements in the nodes of spatial bar structures can be assembled either with bolted connections or with welding. For welded nodal connections, each element should be attached separately. This complicates the process of manufacturing the structure and increases the labour input while assembling this structure. The so-called “tub welding node” does not have such flaws as several bars are joined by a single weld formed during a single pass of the welding machine. The weld of such a node is in a complex stress and strain state. It means that a relatively small weld should constantly take heavy loads. To assess the stress and strain state of the welding node, the researchers conducted numerical studies in the SolidWorks software system. The calculation model of the structural node was based on the results of a particular existing structure examination. These empirical numerical studies revealed that stresses are evenly distributed in the body of the weld, but its surface stresses exceed the stresses inside the weld. There are some areas on the weld surface that exceed the yield strength of steel. Still, the size of these areas is negligible.
The effect of energy dissipation on the dynamic response of reinforced concrete structure
Authors: Fedorova N V , Vu N T , Iliushchenko T A
Published: November 2020

Solving problems associated with protecting buildings from progressive collapse and minimizing resources is becoming increasingly important. In many countries, ensuring such protection is set in accordance with the requirements of national regulatory documents and, therefore, researches aimed at developing effective ways to protect constructive systems from progressive collapse under special actions are relevant. In this regard, the present work presents studies of the influence of energy dissipation in constructive reinforced concrete elements during their sudden structural rearrangement caused by the removal of one of the supporting elements. The hysteretic dispersion accompanying the nonlinear load-unload cycle of the cross-section during crack formation is taken into account. The damping mechanism of reinforced concrete elements of the constructive system is described by the equivalent viscous damping model, based on the hypothesis of proportionality of the damping force and the oscillation velocity. Approbation of the calculated model is carried out in relation to the reinforced concrete frame structures, the physical models of which were tested under the considered loading regime. A comparison of the experimental and calculated parameters shows the effectiveness of the proposed model for assessing the dynamic response of reinforced concrete structures with cracks under the static-dynamic loading regime.
The use of long-span coating plates in case of reconstruction of “wet” spent nuclear fuel storage facilities
Authors: Belash T , Travin S
Published: November 2020

Spent nuclear fuel is one of the most dangerous threats on Earth. Its storage is carried out in various facilities, which include stand-alone “wet” storage facilities for spent nuclear fuel (SNFS). Such storage facilities were designed and built decades ago, when there were no industry requirements for accounting for extreme external impacts. Given the design features of the “wet” SNFS, in the event of their reconstruction it is advisable to consider the possibility of replacing the frame part of the structures with monolithic reinforced concrete elements that can withstand earthquakes and other effects of the required intensity.
Accuracy estimate of technological processes as exemplified by construction works
Authors: Baiburin A Kh
Published: November 2020

The article proposes a calculating method the accuracy of technological processes, taking into account the peculiar features of construction. It gives a graphical interpretation of process accuracy indicators for normal parameter distribution. It shows the differences in approaches to estimating accuracy. It provides actual data on the accuracy of installation works. The method of calculating the process accuracy takes into account the seriousness of defects and the criticality rating of buildings and structures. The article shows the relationship between the indicators of accuracy and defectiveness. The proposed calculation procedure ensures a more accurate estimate of the ratio of the tolerance to the parameter spread. The procedure allows us to estimate the accuracy of construction processes and, if necessary, to adjust the methods of work performance and quality control in order to achieve the specified accuracy.
Energy efficient wall design with stay-in-place formwork
Authors: Kiyanets A V
Published: November 2020

In this paper we analyze contemporary solutions of external wall structures made of cast-in-situ concrete with the use of stay-in-place formwork panels. The advantages of these systems are to reduce the labor input and construction period and to obtain a variety of architectural and planning concepts for buildings. Such systems are widely used in the world. This study is aimed at solving the issues of energy efficiency of external walls with the use of stay-in-place formwork. Some of the most common design solutions are considered. To determine the energy-efficient solution to the stay-in-place formwork option, we used the method of numerical simulation of heat flow processes in structures using the ELCUT 5.1 program. Based on the data obtained, the following results were achieved: an analysis was made of the applied technologies of stay-in-place formwork used to increase the energy-saving characteristics of residential buildings; the thermo-technical characteristics of the selected solutions by numerical simulation were analyzed.
Technological features of application of plaster solutions with ground quicklime
Authors: Zhadanovsky B V , Bazanov V E
Published: November 2020

Lime plaster is widely used in new construction, repair and restoration works. The most common are plaster mortars based on killed lime. However, mortars based on ground unkilled lime might be preferable in some cases. They are characterized by fast setting and strength development; intensive heat emission during unkilled lime hydration makes it possible to carry out work at low temperatures. The paper discusses properties of compound plaster mortars based on ground unkilled lime. The dynamics of temperature and fluidity depending on time have been analyzed for different compositions, as well as mortar compression strength dependence on hold duration before usage for work, and time curves of mortar strength depending on the water to lime relation. To clarify requirements to the physical properties of mortars for mechanical applications, mortar fluidity and temperature were measured during mortar transportation in a mortar pump.
Development of lining formwork for column expansion during reconstruction of building and structures
Authors: Abramyan S G , Oganesyan O V
Published: November 2020

The paper highlights the relevance of the use of stay-in-place formwork systems in improving the load-bearing capacity of columns by way of their expansion during reconstruction of buildings and structures. The review of a number of scientific publications has revealed that the current phase of development of this topic is seeing increased popularity of lining formworks made of composite materials. Therefore, a new formwork system is proposed, which can be made of various materials, such as: steel fiber reinforced concrete, fiber reinforced foam concrete or the composite material PENACOM. A stay-in-place (lining) formwork consists of regular-course and edge assembly elements (sections) forming two openended three-dimensional U-type shapes (shop-fabricated), which, when coupled, make a square or rectangular configuration of the necessary size. Reliable coupling of the elements is achieved by puzzle connections linked both vertically (to form sections) and horizontally (to form semi-sections). The paper describes the assembling technology for lining formworks and compares it with a conventional small-panel wooden formwork, as well as pneumatic and universal formworks previously developed by the authors with the use of composite materials.