bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced natural radioactivity in leachate and groundwater of Belgian landfills
Authors: Pepin S. , Dehandschutter B. , Claes J. , Biermans G. , Nootens S. , Sombré L. , Poffijn A. , Escourrou C. , Bietlot E. , Loo M.
Published: June 2021

To investigate the potential impact on ground- or surface water of natural radionuclides present in waste disposed onto landfills, activity concentrations in leachates, waste water treatment plant discharge and groundwater of several landfills in Belgium have been analysed. 16 currently in operation landfills for hazardous and non-hazardous waste and 10 legacy landfills have been investigated. Results indicate the presence of a slightly enhanced concentration of uranium and other radionuclides in some leachates of landfills in operation. For legacy landfills, enhanced uranium concentration is also observed in some groundwater wells. The presence of uranium in groundwater around landfills is always accompanied by a contamination with other heavy metals and chlorides. No clear linear correlation between concentration of uranium and other metals could be found however. Isotopic ratio between U-238 and U-234 has been calculated in the different water matrices and is close to one in contaminated groundwater, probably indicating an anthropogenic contamination. In all cases, the concentrations of natural radionuclides do not reach values of concern from radiation protection point of view.
Nature of a white opaque substance visualized by magnifying endoscopy in colorectal hyperplastic polyps
Authors: Hirano Akikazu , Yao Kenshi , Ishihara Hiroshi , Hisabe Takashi , Imamura Kentaro , Kanemitsu Takao , Ohtsu Kensei , Hasegawa Rino , Ikezono Go , Takeda Kazuhiro , Miyaoka Masaki , Ueki Toshiharu , Tanabe Hiroshi , Haraoka Seiji , Iwashita Akinori
Published: June 2021

Background and study aims A white opaque substance (WOS) has been observed in the epithelia of gastric, duodenal, and colorectal epithelial adenomas and carcinomas, using magnifying endoscopy (ME). The WOS has been reported to be derived from a dense accumulation of minute lipid droplets in the epithelium. This study aimed to investigate whether the WOS in colorectal hyperplastic polyps was derived from lipid droplets accumulated in the epithelium, as observed in the case of gastric, duodenal, and colorectal epithelial neoplasms.

Patients and methods We analyzed 30 consecutive patients who were positive for the WOS, as visualized in colorectal hyperplastic polyps by ME with narrow-band imaging and 30 consecutive patients who were negative for the WOS. Biopsy specimens obtained from the polyps were immunostained with anti-adipophilin antibody to determine the correlation between the presence of the WOS and that of lipid droplets in the epithelium.

Results In all patients, the epithelial cells were histologically positive for adipophilin. However, the area of adipophilin-positive epithelial cells in the WOS-positive group was significantly larger than that in the WOS-negative group (P < 0.001). The density of the WOS was strongly and positively correlated with the area of adipophilin-positive cells.

Conclusions This study reveals that the WOS visualized in the superficial layers of colorectal hyperplastic polyps is produced by a dense accumulation of minute lipid droplets in the epithelia of the polyps.
Skoliose und Thorax im Kindes- und Jugendalter
Authors: Heyde Christoph-Eckhard , Heinz von der Höh Nicolas , Schumann Eckehard , Völker Anna
Published: June 2021

Idiopathische Skoliosen im Wachstumsalter sind dreidimensionale Deformitäten mit Auswirkungen auf den gesamten Rumpf. Das Wachstum der Wirbelsäule ist eng mit dem Wachstum des Thorax verbunden. Ausgeprägte Fehlstellungen oder langstreckige Stabilisierungen führen zu Beeinträchtigungen der Entwicklung der Wirbelsäule. Dies führt, insbesondere bei Wachstumsstörungen im Bereich der thorakalen Wirbelsäule, zu einer Beeinträchtigung der Thoraxentwicklung und, im jungen Alter, der Entwicklung der Lunge.

Die heute verfügbaren therapeutischen Ansätze zielen daher auf eine dreidimensionale Korrektur der Wirbelsäule unter besonderer Berücksichtigung der regelrechten Entfaltung eines möglichst symmetrischen Thorax. Konservativ stehen dafür spezielle krankengymnastische Programme und die Korsetttherapie zur Verfügung. Operativ kann bei hoher Wachstumsreserve mit wachstumslenkenden Systemen und im Adoleszentenalter mit endgültigen korrigierenden und fusionierenden Eingriffen gearbeitet werden.
Performance of 3 mL versus 5 mL Discarded Volume for Blood Sampling from Central Venous Access Device
Authors: Lalthanthuami HT , Kumari MJ , Venkateswaran R , Lakshmi PR , Ramamoorthy Lakshmi
Published: June 2021

Background Central venous access devices (CVAD) are an essential part of safe practices in critical care, which enable effective venous access and help in avoiding repeated venipuncture. Discard method is widely practiced for blood sampling. A single occasion of blood sampling may cause minimal blood loss; however, the cumulative volume sequential sampling may become clinically signiﬁcant. The study aims to reduce diagnostic blood loss, ensuring that the subsequent blood sample is not diluted or contaminated by residual intraluminal ﬂuid.

Patients and Methods Within-subjects comparative design was adopted for 64 adult patients in the medical intensive care unit of a tertiary hospital. Two blood samples, using 3 mL and 5 mL discarded volume methods, were collected from each patient. Six serum parameters were measured on each of the paired samples and compared.

Statistical Analysis Used Paired t-test and Wilcoxon signed rank test were used for comparing the two methods. Bland–Altman plot analysis and intraclass correlation were used for clinically meaningful analysis.

Results When tested for fixed bias, there is no statistically significant difference between the methods. Potassium and creatinine levels showed significant proportional bias. The agreement limits of sodium, potassium, creatinine, and direct bilirubin were outside the clinically accepted interval, but the proportion of samples outside these intervals was less than 10%. All serum parameters showed excellent reliability, except for sodium which demonstrated good reliability.

Conclusions The practice of discarding 3 mL of blood for discard method is suggested, instead of the standard 5 mL to reduce iatrogenic blood loss. Thus, nurses in critical care are uniquely positioned to limit the diagnostic blood loss while obtaining blood samples.
Review of neuronal growth and control highlights interdisciplinary future
Authors: Johnson-Groh Mara
Published: June 2021

An accessible summary of different neuronal growth mechanism and applications to neuroengineering are presented in a review of neuronal growth and control written for those in and out of the field.
Preparation of silver and gold nanoparticles by the pinhole DC plasma system
Authors: Čechová L. , Krčma F. , Kalina M. , Man O. , Kozáková Z.
Published: June 2021

Silver and gold nanoparticles were produced using the pinhole discharge generated by dc non-pulsing high voltage directly in a precursor solution. Silver nitrate solution was used as the precursor for silver nanoparticles, and chloroauric acid was used as the precursor for gold nanoparticles. Effects of discharge time, precursor concentration, and additives such as reduction agent (ethylene glycol) and capping agent (polyethylene glycol and sucrose) were studied. Nanoparticles were mainly analyzed by UV-VIS spectrometry. The size of prepared nanoparticles was determined by the dynamic light scattering with backscattering detection. To determine the stability of nanoparticles, the zeta potential was measured by the electrophoretic light scattering. It was found that the absorption maximum of nanoparticles increases with the time of the discharge treatment and concentration of the precursor. The size of silver nanoparticles ranged from 10 to 1000 nm and the final solution had higher polydispersity. The size of Au nanoparticles ranged from 10 to 100 nm, depending on the precursor concentration. The most stable particles were prepared from the pure precursor solution without any additives. The addition of ethylene glycol stimulated the reduction process of nanoparticles from the solution but it decreased their zeta potential. Final particles were less stable, which started to form larger structures that tended to sediment. Added capping agent decreased the input of power needed for the stable discharge operation. The formation of silver and gold nanoparticles was confirmed by scanning electron microscopy with the energy dispersion spectrometer. Both silver and gold particles had spherical shapes.
Band energy landscapes in twisted homobilayers of transition metal dichalcogenides
Authors: Ferreira F. , Magorrian S. J. , Enaldiev V. V. , Ruiz-Tijerina D. A. , Fal'ko V. I.
Published: June 2021

Twistronic assembly of 2D materials employs the twist angle between adjacent layers as a tuning parameter for designing the electronic and optical properties of van der Waals heterostructures. Here, we study how interlayer hybridization, weak ferroelectric charge transfer between layers, and a piezoelectric response to deformations set the valence and conduction band edges across the moiré supercell in twistronic homobilayers of MoS2, MoSe2, WS2, and WSe2. We show that, due to the lack of inversion symmetry in the monolayer crystals, bilayers with parallel (P) and antiparallel (AP) unit cell orientations display contrasting behaviors. For P-bilayers at small twist angles, we find band edges in the middle of triangular domains of preferential stacking. In AP-bilayers at marginal twist angles (θAP<1°), the band edges are located in small regions around the intersections of domain walls, giving highly localized quantum dot states.
Seemingly asymmetric atom-localized electronic densities following laser-dissociation of homonuclear diatomics
Authors: Bouakline Foudhil , Saalfrank Peter
Published: June 2021

Recent experiments on laser-dissociation of aligned homonuclear diatomic molecules show an asymmetric forward–backward (spatial) electron-localization along the laser polarization axis. Most theoretical models attribute this asymmetry to interference effects between gerade and ungerade vibronic states. Presumably due to alignment, these models neglect molecular rotations and hence infer an asymmetric (post-dissociation) charge distribution over the two identical nuclei. In this paper, we question the equivalence that is made between spatial electron-localization, observed in experiments, and atomic electron-localization, alluded by these theoretical models. We show that (seeming) agreement between these models and experiments is due to an unfortunate omission of nuclear permutation symmetry, i.e., quantum statistics. Enforcement of the latter requires mandatory inclusion of the molecular rotational degree of freedom, even for perfectly aligned molecules. Unlike previous interpretations, we ascribe spatial electron-localization to the laser creation of a rovibronic wavepacket that involves field-free molecular eigenstates with opposite space-inversion symmetry i.e., even and odd parity. Space-inversion symmetry breaking would then lead to an asymmetric distribution of the (space-fixed) electronic density over the forward and backward hemisphere. However, owing to the simultaneous coexistence of two indistinguishable molecular orientational isomers, our analytical and computational results show that the post-dissociation electronic density along a specified space-fixed axis is equally shared between the two identical nuclei—a result that is in perfect accordance with the principle of the indistinguishability of identical particles.
Micromagnetic modeling of magnetic domain walls in curved cylindrical nanotubes and nanowires
Authors: Skoric L. , Donnelly C. , Abert C. , Hierro-Rodriguez A. , Suess D. , Fernández-Pacheco A.
Published: June 2021

We investigate the effect of curvature on the energy and stability of domain wall configurations in curved cylindrical nanotubes and nanowires. We use micromagnetic simulations to calculate the phase diagram for the transverse wall (TW) and vortex wall (VW) states in tubes, finding the lower energy configuration and the metastability region where both types of walls can exist. The introduction of curvature shifts the range for which the TW is the ground state domain wall to higher diameters and increases the range of metastability. We interpret this behavior to be primarily due to the curvature-induced effective Dzyaloshinskii–Moriya term in the exchange energy. Furthermore, we demonstrate qualitatively the same behavior in solid cylindrical nanowires. Comparing both tubes and wires, we observe how while in tubes curvature tends to suppress the transformation from the TW to VW, in wires it promotes the transformation of the VW containing the Bloch point into the TW. These findings have important implications in the fundamental understanding of domain walls in 3D geometries and the design of future domain wall devices.
Axisymmetric jet manipulation using multiple unsteady minijets
Authors: Perumal Arun Kumar , Zhou Yu
Published: June 2021

A turbulent round jet with a Reynolds number of 8000 based on the minijet exit diameter is experimentally manipulated using 1–6 unsteady radial minijets. Five control parameters are investigated, including the minijet number or configuration (N), the duty cycle (α) of minijet injection, and the mass flow rate, excitation frequency, and diameter ratio (Cm,N, fe/f0, and d/D) of an individual minijet to a main jet. The decay rate (Ke) of the jet-centerline mean velocity under manipulation strongly depends on these five parameters. The typical flow structures or conceptual flow models are proposed for each minijet configuration based on extensive measurements. Three distinct mechanisms behind the highly effective manipulation are identified and discussed from the flow structures. It has been found that the optimal fe/f0 and α, i.e., (fe/f0)opt and αopt at which the maximum Ke or Ke,max occurs, do not vary with N, though optimal Cm,N or (Cm,N)opt does. Empirical scaling analysis performed under (fe/f0)opt reveals that the relationship Ke = g1 (N, Cm,N, α, d/D) may be reduced to Ke/Ke,max = g2 ζ, where g1 and g2 are different functions, and the scaling factor ζ = Cm,N/(Cm,N)opt, representing physically the minijet penetration depth. Both Ke,max and (Cm,N)opt are found to depend on N, α, and d/D. Discussion conducted based on Ke/Ke,max = g2 ζ provides important insight into the jet control physics. It is also discussed how fe/f0 and α are connected to the vortex interaction and, hence, Ke.
Sub-100 nm high spatial frequency periodic structures driven by femtosecond laser induced desorption in GaAs
Authors: Sarracino Alex , Ansari Abdul R. , Torralva Ben , Yalisove Steven
Published: June 2021

This paper presents a previously unreported mechanism for the formation of High Spatial Frequency Laser Induced Periodic Surface Structures (HSFL) in GaAs upon irradiation by femtosecond laser pulses (repetition rate = 1 kHz, τ = 150 fs, λ = 390 nm) that is driven by point defect diffusion, desorption of surface atoms, and roughening of the surface. The HSFL have trenches that are 100 nm deep, an average spatial period of 65 nm, and are completely below the original surface. Sub-100 nm periodicity with high depth to period aspect ratio has not been previously observed in GaAs. In the proposed mechanism, laser irradiation generates point defects that diffuse to the surface. Interstitials that reach the surface can be easily desorbed and the remaining vacancies coalesce into vacancy islands. This results in a rough surface, which can excite surface plasmon polaritons. Despite our observations of periodicity corresponding to SPPs, calculations done using the excited dielectric function indicate that SPPs should not be supported. This points to the need to incorporate the cumulative effects of laser irradiation in existing models. This paper also presents evidence that desorption can also occur during HSFL formation in GaAs when irradiated with 780 nm in vacuum. The HSFL have the similar spatial period as GaAs irradiated in air with 780 nm, but completely below the original surface.
A simple method to generate arbitrary laser shapes for stimulated Raman adiabatic passage
Authors: Ming Hu , Wang Yaning , Zhu Lingxiao , Wang Guochao , Jia Aiai , Li Qixue , Zhang Xu , Zhang Huankai , Yan Shuhua , Yang Jun
Published: June 2021

Stimulated Raman adiabatic passage (STIRAP) is an effective technique to transfer state coherently with the features of both high fidelity and robustness in the field of quantum information and quantum precise measurement. In this note, we present a simple method to generate arbitrary laser shapes for STIRAP by controlling the modulation depth of the electro-optic modulator (EOM) and the diffraction efficiency of the acoustic–optic modulator (AOM) simultaneously. The EOM and AOM are used to control the power ratio between the two Raman lasers (pumping laser and Stokes laser) and the total power, respectively. Compared with the traditional method by combining two Raman lasers separated in space, this method has the advantage of simple structure and insensitivity to the environment disturbance, which would degrade the relative phase noise between two Raman lasers.
Feral cat (
Authors: Anderson Hannah , Richards Brooke , Ross William , Palmer Russell
Published: June 2021

Rothschild’s rock-wallaby (Petrogale rothschildi) is endemic to the Pilbara and Ashburton regions of Western Australia. This large species of rock-wallaby is currently not recognised as threatened but is poorly known. Feral cats are a serious threat to many mainland Australian mammals, including some species of rock-wallaby, however their impact on P. rothschildi is largely unknown. Here we provide the first account of feral cat predation on Rothschild’s rock-wallaby, which was confirmed via genetic analysis. Common rock rats were abundant at the time and are the primary prey for cats, suggesting this was an incidental predation event by this highly opportunistic predator.
Probiotics and gut health: linking gut homeostasis and poultry productivity
Authors: Shini S. , Bryden W. L.
Published: June 2021

The use of probiotics in poultry production has increased rapidly, and this movement has been promoted by global events, such as the prohibition or decline in the use of antibiotic growth promotants in poultry feeds. There has been a persistent search for alternative feed additives, and probiotics have shown that they can restore the composition of the gut microbiota, and produce health benefits to the host, including improvements in performance. Probiotics have shown potential to increase productivity in poultry, especially in flocks challenged by stressors. However, the outcomes of probiotic use have not always been consistent. There is an increasing demand for well defined products that can be applied strategically, and currently, probiotic research is focusing on delineating their mechanisms of action in the gut that contribute to an improved efficacy. In particular, mechanisms involved in the maintenance and protection of intestinal barrier integrity and the role of the gut microbiota are being extensively investigated. It has been shown that probiotics modulate intestinal immune pathways both directly and through interactions with the gut microbiota. These interactions are key to maintaining gut homeostasis and function, and improving feed efficiency. Research has demonstrated that probiotics execute their effects through multiple mechanisms. The present review describes recent advances in probiotic use in poultry. It focuses on the current understanding of gut homeostasis and gut health in chickens, and how it can be assessed and improved through supplementation of poultry diets with probiotics in poultry diets. In particular, cellular and molecular mechanisms involved in the maintenance and protection of gut barrier structure and function are described. It also highlights important factors that influence probiotic efficacy and bird performance.
Chemical and genetic rescue of in vivo progranulin-deficient lysosomal and autophagic defects.
Authors: Doyle James J. , Maios Claudia , Vrancx Céline , Duhaime Sarah , Chitramuthu Babykumari , Bennett Hugh P. J. , Bateman Andrew , Parker J. Alex
Published: June 2021

Significance

Uncovering the genetic and cellular mechanisms of frontotemporal dementia (FTD) may lead to new therapeutic strategies. Mutations in theGRNgene are linked to FTD; the underlying cellular mechanisms are still unknown, but current research points to lysosomal dysfunction. Using the model organismCaenorhabditis elegans, we found a link betweenpgrn-1/GRNmutations, and sphingolipid metabolism and autophagy. We further identified small molecules that attenuated severalpgrn-1/GRNphenotypes in vivo. These results offer sphingolipid metabolism as a potential mechanism contributing to FTD pathogenesis and suggest that efforts to restore sphingolipid homeostasis may be a beneficial therapeutic approach.
Physical bioenergetics: Energy fluxes, budgets, and constraints in cells
Authors: Yang Xingbo , Heinemann Matthias , Howard Jonathon , Huber Greg , Iyer-Biswas Srividya , Le Treut Guillaume , Lynch Michael , Montooth Kristi L. , Needleman Daniel J. , Pigolotti Simone , Rodenfels Jonathan , Ronceray Pierre , Shankar Sadasivan , Tavassoly Iman , Thutupalli Shashi , Titov Denis V. , Wang Jin , Foster Peter J.
Published: June 2021

Cells are the basic units of all living matter which harness the flow of energy to drive the processes of life. While the biochemical networks involved in energy transduction are well-characterized, the energetic costs and constraints for specific cellular processes remain largely unknown. In particular, what are the energy budgets of cells? What are the constraints and limits energy flows impose on cellular processes? Do cells operate near these limits, and if so how do energetic constraints impact cellular functions? Physics has provided many tools to study nonequilibrium systems and to define physical limits, but applying these tools to cell biology remains a challenge. Physical bioenergetics, which resides at the interface of nonequilibrium physics, energy metabolism, and cell biology, seeks to understand how much energy cells are using, how they partition this energy between different cellular processes, and the associated energetic constraints. Here we review recent advances and discuss open questions and challenges in physical bioenergetics.
High-resolution multicontrast tomography with an X-ray microarray anode–structured target source
Authors: Zan Guibin , Gul Sheraz , Zhang Jin , Zhao Wei , Lewis Sylvia , Vine David J. , Liu Yijin , Pianetta Piero , Yun Wenbing
Published: June 2021

Significance

Talbot–Lau interferometry (TLI) holds remarkable potential for multicontrast X-ray imaging but suffers from technical challenges associated with microfabrication and limited efficiency. We tackle the frontier challenges in this field by developing a microarray anode–structured target source with a built-in structured illumination scheme. Our development facilitates high-resolution and high-sensitivity TLI imaging without the absorption source grating. We demonstrate the tri-contrast tomography capability with a Drum fish tooth specimen and separate the biological features with different combinations of physical properties. Our approach not only addresses the long-standing challenges in the field of X-ray TLI phase-contrast imaging but also features a compact setup that can potentially be made broadly available to academia research and industrial applications.
Efficient empirical determination of maximum permissible error in coordinate metrology
Authors: Thompson Adam , Southon Nicholas , Fern Florian , Stupfler Gilles , Leach Richard
Published: June 2021

Maximum permissible errors (MPEs) are an important measurement system specification and form the basis of periodic verification of a measurement system’s performance. However, there is no standard methodology for determining MPEs, so when they are not provided, or not suitable for the measurement procedure performed, it is unclear how to generate an appropriate value with which to verify the system. Whilst a simple approach might be to take many measurements of a calibrated artefact and then use the maximum observed error as the MPE, this method requires a large number of repeat measurements for high confidence in the calculated MPE. Here, we present a statistical method of MPE determination, capable of providing MPEs with high confidence and minimum data collection. The method is presented with 1000 synthetic experiments and is shown to determine an overestimated MPE within 10% of an analytically true value in 99.2% of experiments, while underestimating the MPE with respect to the analytically true value in 0.8% of experiments (overestimating the value, on average, by 1.24%). The method is then applied to a real test case (probing form error for a commercial fringe projection system), where the efficiently determined MPE is overestimated by 0.3% with respect to an MPE determined using an arbitrarily chosen large number of measurements.
Geotechnical engineering and alternative aggregates, tailings
Authors: Vaníček Ivan , Herza Jiří
Published: June 2021

Originally geotechnical engineering is connected with ground with rock and soil environment, focused on geotechnical structures which are in interaction with ground, and therefore we often speak about construction on, with or in ground. However, during last decades, especially with increasing focus on environment protection, geotechnical engineering is dealing also with other materials, denoted as alternative aggregates. They are mostly a byproduct of mining or industrial activities for which a method of future use is being sought. Typical examples are fly ash, construction and demolition waste, slag and different tails from chemical treatment of target ores which have similar character as natural soil and are produced in large volumes. Therefore, there is legitimate question about their possible use in earth structures, preferably of transport engineering. If external circumstances (e.g. distance of origin from the place of use) are favourable, geotechnical engineering is focused on two basic aspects - on possible negative impact on environment due the chemical composition of leachate or on structural stability. If there is no opportunity for their further use we have to guarantee safe deposition. In this case we are speaking about earth structures of environmental engineering as tailing dams, spoil heaps, landfills and are responsible for their safety. The paper is therefore focused on three main problems: Utilization of alternative aggregates (e.g. large volume waste) in transport engineering; Problems of earth structures of environmental engineering, where large volume waste is stored, as e.g. tailing dams and Structural collapse of tails studied in micro scale in laboratory.
Experience in application of drilled injection piles for building and structure strengthening
Authors: Salnyi I S , Pronozin Yu A , Naumkina Ju V , Karaulov A M
Published: June 2021

The paper presents the experience of building and structure strengthening in Tyumen soil conditions which are often presented by a soft water saturated clay and sand layer of the quaternary period. All buildings mentioned in the paper had uneven settlements due to complex engineering and geological conditions and the wrong choice of foundation type. Thin drilled injection piles with a diameter of 200 mm were used for foundation strengthening. All the piles were installed on the solid soil base during the drilling process regardless of the depth of its location. No rules have so far been approved to calculate the bearing capacity of thin drilled injection piles. That was the reason for defining the drilled injection pile bearing capacity at every facility. The paper describes the methods and test results obtained in the study. It was found out that all piles had unexpectedly high bearing capacity. The paper also contains the results of geotechnical monitoring before and after base building strengthening by drilled injection piles which show the current decrease of settlements and the efficiency of this base strengthening method.
Comparative analysis of the dynamic stability of a multistorey building with different base arrangements
Authors: Sobolev E S , Berezin E K , Kechina T V
Published: June 2021

The article presents the results of studies by the numerical method of pile and slab foundation with a reinforced base by the method of deep soil mixing (DSM) under the influence of seismic loads using the LIRA-SAPR software package, which implements the finite element method. The parameters of the computer model are presented, which make it possible to obtain the calculation results. A comparative analysis of the calculation results is carried out. In the course of the study, it was revealed that the use of a slab foundation with a reinforced base by the deep soil mixing method (DSM) is more effective than a pile foundation under seismic loads.
Geomonitoring of structural safety of unique underground sewage facilities operating for a long term in difficult soil and anthropogenic conditions of the megacity
Authors: Perminov N A
Published: June 2021

Anthropogenic and dynamic impacts on facilities of underground urban infrastructure increase at intensive development of megacities. The unique long-operating underground structures of sewage system require special protection against anthropogenic influence as their wear degree in difficult soil conditions reaches 70% and more. Therefore, providing structural (mechanical) safety of underground structures of excessive level of danger and responsibility defines sustainable operation and future development of geotechnical infrastructure of the megacity in general. Long-term studying dynamics of changes of technical state of underground sewage structures of the megacity, long operating (for more than 70 years) in soft soils, allowed establishing regularities of influence of intensive anthropogenic and dynamic impacts on this process. For the first time, based on developed continuous models of defective structures potentially dangerous sections have been identified, they are subjected to manifestation of critical failures; ways of their correction are presented. Numerical simulation has defined borders of defectless joint operation of the system “target area – geobulk – underground structure”. Scientific substantiation of boundaries of areas with potentially dangerous sections of underground sewage facilities with account of external anthropogenic and dynamic impacts constitutes the basis for elaborating regulations on safe development of geotechnical infrastructure of the historical area of St. Petersburg. The proposed methods of monitoring and protection of geotechnical infrastructure have been successfully used for many years by St. Petersburg Vodokanal in areas of influence of anthropogenic factors and objects under construction on underground structures, they ensure an optimal combination of sustainable operation and development of geotechnical infrastructures of megacities.
Comparative analysis of calculation methods seismic impact and influence of methods on the safety factor for hydraulic structures
Authors: Ter-Martirosyan A Z , Sergeev S A , Anzhelo G O , Ermoshina L Y , Almakaeva A S
Published: June 2021

Rasskazov L.N., Bestuzheva A.S., Sainov M.P., CHernysh A.S., Francesco Castelli and many others were engaged in studies of the stability of slopes under seismic impact. The paper considers numerical methods for assessing the seismic stability of embankment dams in a flat and three-dimensional problems in two ways: a direct dynamic method and a pseudo-static method. Several simulation cases are considered in a flat problem on a test problem using soil properties taken from a real site of an operating hydroelectric power plant. During the simulation, the following main simulation cases were considered: the natural stability; calculation without static components; calculation with static components; impact of free vibrations; calculation with full accelerogram; calculation with static deformation properties of soils; calculation with dynamic deformation properties of soils; calculation with undrained strength of soils; pseudostatic method. The analysis of the results showed that the calculation of the seismic stability of an embankment dam by the direct dynamic method gives the results that are closest to reality, in contrast to the pseudo-static calculation method.
Influence of the enclosing structure of a trench-type wall in the ground on the heeling of a high-rise building on a raft foundation
Authors: Znamenskii V V , Ganbold A
Published: June 2021

This article presents the results of studying the influence of the enclosing structure of the pit, made according to the technology of the reinforced concrete wall in the ground of the trench type, on the heeling of a high-rise building on a raft foundation. The study was performed using the numerical method with the PLAXIS 2D software package. The influence of the wall in the ground on the building roll was determined depending on the distance from the wall in the ground to the edge of the raft foundation of the building, the embedding depth of the wall in the ground below the bottom of the excavation and the characteristics of the contact element. The degree of influence of each of these factors on the heeling of the raft foundation was determined by the factor analysis based on the theory of experimental planning. The mosaics of deformations of the soil massif at the base of the raft foundation are given, as well as graphs of the dependence of the change in heeling for the considered factors of influence. According to the study results, the boundaries of the significant influence of each of the factors considered, as well as the walls in the ground as a whole on the heel of the building are determined. The issues are discussed on applications of the study results to reduce the heeling of high-rise buildings at the design stage.
Numerical analysis and geomonitoring of behaviour of foundation of Abu-Dhabi Plaza in Nur-Sultan
Authors: Buranbayeva A M , Zh Zhussupbekov A , Omarov A R
Published: June 2021

In similarity to every civilization in history originated from the riverside, the city of Nur-Sultan, which the new capital of Kazakhstan developed around the Ishim River. During the last 25 years, many high-rise buildings supported by pile foundations are rising in Nur-Sultan. The paper presents the monitoring of development for the unique residential building of 310 m high with 4-story underground parking. The pile raft foundation (for block R) analyses had designed using Geocthenical soft, which can assess in precise of the deformations, occurs in soil. In the paper presidents, method monitoring raft foundations for block R, the height of this block R is 320 meters. Design of distributed fibre optic strain sensing system (DFOSS) has been employed for measuring the strain in civil engineering structures for over a decade. It is now harnessed worldwide for monitoring a wide range of structures slab pile foundation. Geotechnical monitoring data of adjacent building and utility systems settlement caused by the construction of presented high-rise buildings were compared to numerical modelling results, predicted, and permissible values.

Finally, the raft foundation recommended for future high-rise buildings constructed of Nur-Sultan city on complex soils.
Influence of soil thermophysical properties on the flow of thermal energy taken by the energy pile
Authors: Zakharov A V , Ovchinnikov N M
Published: June 2021

The depletion of traditional fossil energy sources leads to an increasing development of non-traditional energy sources. One of the promising directions of alternative energy is the use of low-potential energy of the soil for heating buildings and structures for various purposes. Heat extraction is possible through the use of energy foundation. However, their rational design is impossible without a careful assessment of a large number of factors that affect the potential value of thermal energy extracted from the soil. The purpose of this work was to build a whole methodology to assess the degree of influence of soil thermophysical properties, in particular, such as heat capacity and thermal conductivity, on the amount of heat energy selected energy pile. The formulation and analysis of the numerical experiment to identify the desired dependencies. The matrix of experiment planning is made. The numerical simulation of the energy pile of different geometric parameters in different soil conditions is performed. Statistical processing of the obtained experimental data was carried out. A quadratic regression equation was developed to determine the amount of heat through the side surface of the pile depending on the length of the pile, its diameter, heat capacity and thermal conductivity of the soil. The analysis of this equation for the purpose of estimation of degree of influence of initial thermophysical parameters of soil on value of thermal energy of the selected pile is carried out.
Vibrations of a viscoelastic isotropic plate under periodic load without considering the tangential forces of inertia
Authors: Abdikarimov R , Vatin N , Normuminov B , Khodzhaev D
Published: June 2021

A mathematical model of the problem of viscoelastic isotropic plate vibrations based on the Kirchhoff-Love hypothesis in a geometrically nonlinear formulation was presented. The mathematical model was built without considering the tangential forces of inertia. To describe the viscoelastic properties of the plate material, a weakly singular Koltunov-Rzhanitsyn kernel with three different rheological parameters was chosen. To solve the problem of parametric vibrations of a viscoelastic plate with a weakly singular relaxation kernel, a numerical method based on the use of quadrature formulas was applied. A discrete model of this problem was first constructed using the Bubnov-Galerkin method; i.e., a system of integro-differential equations with variable coefficients was obtained, and then, using a numerical method based on the elimination of a singularity of the kernel, the problem of parametric vibrations of viscoelastic rectangular plates was solved. The influence of the viscoelastic properties of the material and the variability of the plate thickness on the oscillatory process was shown.
Analysis of horizontal pile displacement caused by pit excavation
Authors: Mangushev R A , Kolesnik D S
Published: June 2021

In the case of thick soft and unstructured soils, pit excavation causes 20-75% of pile heads to have higher-than-normal horizontal displacements. The paper presents the results of statistical analysis for 9865 piles installed in pile fields at 17 construction sites in St. Petersburg, Perm, and Volgograd. We note that the distribution of frequencies of horizontal pile displacements follows a normal law. During the analysis, we identified the main factors affecting pile displacement: the time when a pile is in the slope, the properties of the cut soils, their tendency to softening, the excavation scheme, and the availability of pile head anchorage. The paper justifies the effectiveness of pit excavation in work zones of up to two meters deep with changes in the direction of machinery movement. We provide recommendations for raft design and analysis with account for possible displacement of pile heads.
Influence of permafrost degradation on piles bearing capacity
Authors: Nikiforova N S , Konnov A V
Published: June 2021

The permafrost zone is one of the main natural systems in the Russian Federation that are exposed to global warming. The temperature of permafrost soils changes, the seasonal thaw zone increases, the process of permafrost degradation is started, influencing the strength properties of the soils. The study sought to assess climate change in terms of the impact on the bearing capacity of the soil under buildings and structures built in the 1960s and 1980s on the principle of maintaining the permafrost condition of soils. On the basis of published archival and forecast data on the increase rate in the active layer thickness and the rising trends in the temperature of permafrost soils for four geographical regions of Russia (North of the European part, North of Western Siberia, Middle Siberia, Yakutia) a reduction in the bearing capacity of the standard reinforced concrete pile was determined (35x35 cm section, 10 m long). The study showed that, for most regions, the reduction in the bearing capacity of the pile is currently on average level (10-20 %). However a high (>30%) decrease is expected by 2050.
Investigation of operation of newly designed anchor pile
Authors: Kostina O V , Bochkareva T M
Published: June 2021

The article describes design of a pile with new rotary anchors for foundations of buildings operating on variable loads or on heaving soils. The results of plate load tests on piles’ pressing in with one- and two anchor levels are presented. Based on calculations on bearing capacity of piles of proposed design, the adequacy of data on determination of its bearing capacity obtained by experimental method is calculated. Bearing capacity of anchor piles for pulling out is determined by calculations. Anchors located at one level at the height of pile increase its bearing capacity for pressing in by 20%, and increase it for pulling out by 94%. Anchors located at two levels at the height of pile increase bearing capacity of pile for pressing in by 60%, and increase bearing capacity for pulling out by three times. A decrease in the settlement of pile of proposed design is determined by the results of plate load tests on pressing in and it amounts to 85% for a pile with one-level anchors and to 94% for a pile with two-level anchors.
Research horizontally loaded pyramidal piles with compacted bottom and their calculation
Authors: Gotman A L , Krutyaev S A
Published: June 2021

The results of experimental and theoretical research in work features of a rammed pyramidal pile with compacted bottom for horizontal load in clayey soils are presented. The experimental cast-in situ pyramidal piles with compacted bottom were made at 2 experimental sites, composed of clayey soils. Static horizontal load tests were carried out. At each stage of loading, horizontal displacements were measured at the load application level and at a height of one meter from the top edge of the pile. The “horizontal load - pile head displacement” dependencies were obtained. It was found that the rotation of the pile in the soil occurs without bending, i.e. according to a rigid scheme, and also that compacted bottom prevents horizontal displacement of the pile bottom. Based on the analysis of the results of static tests of piles, a design scheme has been created, in which the pile is considered as a rigid rod buried in a multilayer linearly deformable base with a point of zero displacements at the lower end of the pile. In accordance with the design scheme, an analytical method for calculating a pyramidal pile with compacted bottom for horizontal load and bending moment has been developed. The calculation method allows to determine the horizontal displacement of the pile head in any section along the depth, the angle of rotation of the pile, bending moment and shear force along the length of the pile.
Investigation of particularities of the stress-strain state of the sandy basis under loading conditions of rough stamps
Authors: Skibin G M
Published: June 2021

The analysis of the results of the experimental researches conducted in Platov South-Russian State Polytechnic University (Novocherkassk Polytechnic Institute), in conditions of tape and axisymmetrical basis loadings permits to identify general patterns of the sand basis operating in case of different loading conditions, to consistently trace the development of ranges of strains, compaction and decompaction and the formation of a condenced core under stamps and to assess this process with the phases of the stress - strain state of the basis.
Method for studying the kinetics of plastic deformation and energy dissipation during fatigue of structural materials
Authors: Zakharchenko K V , Kaygorodtseva A A , Kapustin V I , Shutov A V
Published: June 2021

The evolution of mechanical properties of Russian steel St3 subjected to cyclic elasto-plastic deformation is analyzed under a broad spectrum of loading conditions. This particular material is chosen due to its wide use in industrial facilities operating in Arctic and Russian North. Basic state parameters are determined, including the true strains, secant and tangent moduli, heat generation due to plastic dissipation, thus characterizing the evolution of the thermo-mechanical state. The temporal evolution of kinetic parameters during each loading block provides insights into the hardening and damage accumulation. These data form an experimental basis for development, calibration, and validation of new material models. The main effects are identified and discussed, and the modelling approaches are assessed.
Formation of ceramic targets for solid electrolytes sputtering
Authors: Kunshina G B , Bocharova I V , Ivanenko V I
Published: June 2021

The results of ceramic targets formation from powders of Li1.3Al0.3Ti1.7(PO4)3 and Li6.4Al0.2La3Zr2O12 solid electrolytes by cold pressing with subsequent high-temperature sintering are presented. Solid electrolyte powders of Li1.3Al0.3Ti1.7(PO4)3 (LATP) with the NASICON structure and Li6.4Al0.2La3Zr2O12 (LLZ) with the garnet structure with high Li-ion conductivity were synthesized by methods protected by patents in the RF, suitable for mass production. The conditions for the formation of dense single-phase targets (14 mm in diameter and 8-10 mm thick) from LATP and LLZ (cubic modification) solid electrolytes were established by X-ray diffraction analysis. The ionic conductivity, Li+ ion transfer number and electronic conductivity of LATP and LLZ ceramic targets were determined by electrochemical impedance spectroscopy and potentiostatic chronoamperometry methods.
Materials Microencapsulation Applications in Oil Drilling and Production
Authors: Orlov M V
Published: June 2021

Advancing the materials used in oil drilling and production has significantly augmented the industry’s efforts to improving the processes and preventing the operations failures. Presently, oil drilling and production demand that materials do not simply demonstrate better performance, but also possess some degree of intelligence. The intelligence is induced to the materials by preprogramming a certain response to a change in the surrounding conditions to trigger the function of the used materials. This improves the performance and prevents possible physical damage or mitigates negative changes in the downhole environment during production. Smart responsive microcapsules, with the ability to self-heal the materials, delayed and targeted active release, and could become a viable solution for the challenges the oil drilling and production industry is currently facing. This paper provides an overview of the benefits that a microencapsulation technique has demonstrated when applied to the materials involved in oil drilling and production. It outlines possibilities for improving the well drilling process when products containing microcapsules are applied. Several examples demonstrating the ability to perform downhole treatment seamlessly with pre-designed microcapsules are embedded. The paper puts emphasis on developing smart self-healing materials by integrating microcapsules into the cement sheath as well as the coatings of steel pipes to mitigate costly failures. Finally, the paper shows examples of some outstanding results of microencapsulated materials when applied to the most advanced research areas in the oil industry such as enhanced oil recovery (EOR) and hydraulic fracturing.