bluuebunny/crossref_metadata_2025 huggingface dataset:
Valorization of homogeneous linear catechyl lignin: opportunities and challenges
Authors: Li Yibing , Meng Xianzhi , Meng Rongqian , Cai Ting , Pu Yunqiao , Zhao Zhi-Min , Ragauskas Arthur J.
Published: April 2023

The discovery and valorization of the unique homogeneous linear catechyl lignin (C-lignin) are systematically summarized.
How carbon contamination on the photocatalysts interferes with the performance analysis of CO2 reduction
Authors: You Jiakang , Xiao Mu , Liu Siqi , Lu Haijiao , Chen Peng , Jiang Zhi , Shangguan Wenfeng , Wang Zhiliang , Wang Lianzhou
Published: April 2023

Carbon contamination on the photocatalysts intereferes the performance analysis of photocatalytic carbon dioxide (CO2) reduction reaction (CO2RR).
Effects of Healthy Aging and Gender on the Electrophysiological Correlates of Semantic Sentence Comprehension: The Development of Dutch Normative Data
Authors: Cocquyt Elissa-Marie , Depuydt Emma , Santens Patrick , van Mierlo Pieter , Duyck Wouter , Szmalec Arnaud , De Letter Miet
Published: April 2023

Purpose:

The clinical use of event-related potentials in patients with language disorders is increasingly acknowledged. For this purpose, normative data should be available. Within this context, healthy aging and gender effects on the electrophysiological correlates of semantic sentence comprehension were investigated.

Method:

One hundred and ten healthy subjects (55 men and 55 women), divided among three age groups (young, middle aged, and elderly), performed a semantic sentence congruity task in the visual modality during electroencephalographic recording.

Results:

The early visual complex was affected by increasing age as shown by smaller P2 amplitudes in the elderly compared to the young. Moreover, the N400 effect in the elderly was smaller than in the young and was delayed compared to latency measures in both middle-aged and young subjects. The topography of age-related amplitude changes of the N400 effect appeared to be gender specific. The late positive complex effect was increased at frontal electrode sites from middle age on, but this was not statistically significant. No gender effects were detected regarding the early P1, N1, and P2, or the late positive complex effect.

Conclusion:

Especially aging effects were found during semantic sentence comprehension, and this from the level of perceptual processing on. Normative data are now available for clinical use.
Digital pre‐distortion scheme for an end‐to‐end forward link based on cascade distortions modelling and space‐time‐frequency non‐stationary constraints in LEO‐SIN
Authors: Lu Yin , Minghui Li , Lizhe Liu , Chenhua Sun , Dongdong Wang , Ke Wang , Wenliang Lin , Weijia Zhang , Pengxiao Wei , Wei Cai , Hao Liu , Yaohua Deng
Published: April 2023

In this letter, a novel digital pre‐distortion (DPD) scheme for an end‐to‐end forward link (FL) channel in a satellite internet network (SIN) is first proposed. It aims at the unprecedented challenge of the model of non‐stationary (NS) cascade response consisting of channel fading and non‐linear behaviour of onboard payload. Unlike most existing schemes, the proposed DPD scheme explores a new model to describe the distortion with improved band‐limited memory polynomial (BLMP) by the equivalent response. To decrease the complexity of utilization, the authors design a new strategy to divide the unified non‐stationary situation into several different stationary situations. Meanwhile, a space‐time‐frequency stationary window function (STF‐WF) is proposed to compensate for the signal distortion. The experimental results demonstrate that the proposed schemes realize maximum total degradation (TD) gain by 15%.
A simple metric that correlates with public Wi‐Fi throughput
Authors: Mizuno Yu , Ohishi Yasuhiro , Ishikawa Naoki
Published: April 2023

In the IEEE 802.11 specifications, a wireless fidelity (Wi‐Fi) access point (AP) broadcasts a beacon frame every 0.1024 s, and the received signal strength indicator (RSSI) is measured at a user terminal. RSSI is used as a metric for AP selection, but it does unlikely correlate with the actual quality of service, as has been pointed out in previous literature. In this letter, a simple metric is proposed that correlates with the effective throughput offered by a public Wi‐Fi AP. Specifically, the number of beacon frames within a time window is counted instead of using RSSI. The proposed metric can be easily calculated as it does not rely on advanced techniques such as machine learning. In a realistic IEEE 802.11a/n/ac network, the correlation coefficient between the proposed metric and the effective total throughput is 0.874 in the time window of 1 s, which is higher than a conventional metric, indicating the potential for low‐latency identification of whether a public Wi‐Fi AP can provide good throughput.
Experimental investigation of scatterer‐array‐based decorrelation technique applied to real multiple‐input multiple‐output base station
Authors: Wang Yipeng , Huang Xiaoyu , Zhao Jianyao , Zhong Zhimeng , Sha Wei E.I. , Chen Xiaoming
Published: April 2023

In this paper, a scatterer‐array‐based decorrelation method for improving the multiple‐input multiple‐output (MIMO) performance is proposed for a real application of base station (BS) operating at 780 MHz with a 20‐MHz communication bandwidth. The antenna correlation is reduced by loading a scatterer array designed to increase the MIMO array's effective inter‐element spacing. As a result, the diversity measure is improved, which in turn benefits the MIMO capacity. This method is demonstrated first in simulation to check its performance, which shows about 4% and 20% improvements in MIMO capacity over 20‐MHz communication bandwidth in single‐cell and multi‐cell scenarios, respectively. Then it is applied to a real BS in a realistic urban micro scenario for experimental verification, showing a noticeable throughput improvement without degrading the power coverage of the BS. Note that this is the first time that the scatterer‐array‐based decorrelation technique has been applied to increase the MIMO throughput of a real BS in a real‐life scenario, which thoroughly demonstrates the promising application potential of this technique.
MCNN: Conditional focus probability learning to multi‐focus image fusion via mutually coupled neural network
Authors: Wang Chengchao , Pu Yuanyuan , Wang Xue , Ma Chaozhen , Nie Rencan
Published: April 2023

In this paper, a novel conditional focus probability learning model, termed MCNN, is proposed for multi‐focus image fusion (MFIF). Given a pair of source images, their conditional focus probabilities can be generated by using the well‐trained MCNN, which is further converted into the binary focus masks to directly produce an all‐focus image with no postprocessing. To this end, a fully convolutional encoder is designed with two mutually coupled Siamese branches in MCNN, which include a coupling block that bridge between the two branches to provide conditional information to each other, at different layers, such that the encoder can more strongly extract conditional focus features and further encourage the decoder pixel‐wisely to give more robust conditional focus probabilities. Moreover, a hybrid loss is designed with a structural sparse fidelity loss and a structural similarity loss to force the network to learn more accurate conditional focus probabilities. Particularly, a convolutional norm with good structural group sparse is proposed, to construct the structural sparse fidelity loss. Simulation results substantiate the superiority of our MCNN over other state‐of‐the‐art, in terms of both visual perception and quantitative evaluation.
Runge–Kutta optimization‐based selective harmonic elimination in an H‐bridge multilevel inverter
Authors: Sajid Injila , Sarwar Adil , Tariq Mohd , Bakhsh Farhad Ilahi , Hussan Md Reyaz , Ahmad Shafiq , Mohamed Adamali Shah Noor , Ahmad Akbar
Published: April 2023

The application of iterative techniques for solving the Selective Harmonic Elimination Pulse Width Modulation (SHE‐PWM) problem, such as the Newton–Raphson (NR) method, can tend to get stuck at local optima in the solution space. Additionally, these methods may be sensitive to the initial value estimation of the solution. In contrast, metaheuristic approaches demonstrate resilience in seeking out the optimal solution. As such, this study utilizes the Runge–Kutta (RUN) metaheuristic optimization algorithm to demonstrate the SHE‐PWM technique in multilevel inverters (MLIs), including 5‐ and 7‐level modified H‐bridge (MHB) topology and a 9‐level asymmetric cascaded H‐bridge (CHB) inverter topology. The switching angles are obtained by varying the modulation index from 0.01 to 1.0 in steps of 0.01 for 5‐, 7‐, and 9‐level MLIs. The performance of the RUN algorithm in minimizing the total harmonic distortion (THD) value is verified through simulations in MATLAB/Simulink software. The superiority of RUN is established by comparing the results with state‐of‐the‐art metaheuristic algorithms, such as the Differential Evolution (DE), Genetic Algorithm (GA), and Grey Wolf Optimizer (GWO). Additionally, the switching angles obtained through RUN are validated by hardware experiments. According to the simulation and experimental results, the proposed RUN method exhibits better performance in terms of objective function values, algorithm robustness, fundamental harmonic magnitude, and THD values. The findings confirm the elimination of fifth harmonic, fifth, and seventh harmonics, and fifth, seventh, and ninth harmonics in 5‐, 7‐, and 9‐level MLIs, respectively.
The two rings of (50000) Quaoar
Authors: Pereira C. L. , Sicardy B. , Morgado B. E. , Braga-Ribas F. , Fernández-Valenzuela E. , Souami D. , Holler B. J. , Boufleur R. C. , Margoti G. , Assafin M. , Ortiz J. L. , Santos-Sanz P. , Epinat B. , Kervella P. , Desmars J. , Vieira-Martins R. , Kilic Y. , Gomes Júnior A. R. , Camargo J. I. B. , Emilio M. , Vara-Lubiano M. , Kretlow M. , Albert L. , Alcock C. , Ball J. G. , Bender K. , Buie M. W. , Butterfield K. , Camarca M. , Castro-Chacón J. H. , Dunford R. , Fisher R. S. , Gamble D. , Geary J. C. , Gnilka C. L. , Green K. D. , Hartman Z. D. , Huang C.-K. , Januszewski H. , Johnston J. , Kagitani M. , Kamin R. , Kavelaars J. J. , Keller J. M. , de Kleer K. R. , Lehner M. J. , Luken A. , Marchis F. , Marlin T. , McGregor K. , Nikitin V. , Nolthenius R. , Patrick C. , Redfield S. , Rengstorf A. W. , Reyes-Ruiz M. , Seccull T. , Skrutskie M. F. , Smith A. B. , Sproul M. , Stephens A. W. , Szentgyorgyi A. , Sánchez-Sanjuán S. , Tatsumi E. , Verbiscer A. , Wang S.-Y. , Yoshida F. , Young R. , Zhang Z.-W.
Published: April 2023

Context. Quaoar is a classical trans-Neptunian object (TNO) with an area-equivalent diameter of 1100 km and an orbital semi-major axis of 43.3 astronomical units. Based on stellar occultations observed between 2018 and 2021, an inhomogeneous ring (Q1R, i.e., Quaoar’s first ring) has been detected around this body.

Aims. A new stellar occultation by Quaoar was observed on August 9, 2022, with the aim of improving Quaoar’s shape models and the physical parameters of Q1R, while searching for additional material around the body.

Methods. The occultation provided nine effective chords across Quaoar, pinning down its size, shape, and astrometric position. Large facilities, such as Gemini North and the Canada-France-Hawaii Telescope (CFHT), were used to obtain high acquisition rates and signal-to-noise ratios. The light curves were also used to characterize the Q1R ring (radial profiles and orbital elements).

Results. Quaoar’s elliptical fit to the occultation chords yields the limb with an apparent semi-major axis of 579.5 ± 4.0 km, apparent oblateness of 0.12 ± 0.01, and area-equivalent radius of 543 ± 2 km. Quaoar’s limb orientation is consistent with Q1R and Weywot orbiting in Quaoar’s equatorial plane. The orbital radius of Q1R is refined to a value of 4057 ± 6 km. The radial opacity profile of the more opaque ring profile follows a Lorentzian shape that extends over 60 km, with a full width at half maximum (FWHM) of ∼5 km and a peak normal optical depth of 0.4. Besides the secondary events related to the already reported rings, new secondary events detected during the August 2022 occultation in three different data sets are consistent with another ring around Quaoar with a radius of 2520 ± 20 km, assuming the ring is circular and co-planar with Q1R. This new ring has a typical width of 10 km and a normal optical depth of ∼0.004. Just as Q1R, it also lies outside Quaoar’s classical Roche limit.
An insight into drying-wetting cycles of peat
Authors: Parra-Gómez Luis J. , Muraro Stefano , Jommi Cristina
Published: April 2023

A relevant part of the geotechnical infrastructure in the north of Europe and overseas is built on soft organic soils, including peat. Peat is extremely vulnerable to climate-related hazards as increased temperature accelerates drying, shrinkage and decomposition of the organic matter. Peat exhibits dramatic changes in volume with changes in water content. As the material deforms, the pore space evolves and changes the water retention response. The evolution of the pore space leads to a hysteretic relationship between suction, water content, and void size distribution. In this work, data from free shrinkage-swelling and suction measurements on natural fibrous peat subjected to drying and wetting cycles are presented and discussed. The water retention and shrinkage behaviour of the samples are modelled by accounting for capillarity and considering the evolution of the pore size distribution. X-Ray computer tomography was used to explore the change in the pore space upon shrinkage and drying. The experimental evidence shows that peat experiences distinct shrinkage zones including one where accelerated contraction occurs. Such behaviour is explained as a consequence of the interactions of an aggregated fabric. This is supported by the conceptual modelling approach that highlights the pivotal role of the evolving pore space.
Capillary cohesion of different granular materials determined from uniaxial compression and water retention tests
Authors: Heinrich Dennis , Milatz Marius
Published: April 2023

In this conference contribution, we present and discuss the results for capillary cohesion of different granular materials determined through different approaches. First, we consider macroscopic uniaxial compression tests with varying degrees of saturation. Second, we derive theoretical capillary cohesion from the water retention curve (WRC) measured in macroscopic water retention experiments. Finally, capillary cohesion is calculated from air-water interfacial areas and solid-water interfacial areas extracted from CT images acquired during a cyclic water retention experiment. An attempt is made to link the macroscopic results of capillary cohesion based on microscopic insights from CT imaging experiments.
An insight on the experimental volumetric behaviour of gassy soils
Authors: Mele Lucia , Lirer Stefania , Flora Alessandro
Published: April 2023

Induced Partial Saturation (IPS) is one of the most innovative and promising countermeasures to mitigate soil liquefaction risk. Mechanical benefits of air/gas bubbles occluded within the pore water have been studied in the last decade through undrained cyclic tests on quasi-saturated (gassy) soils, demonstrating that the increased pore fluid compressibility prevents liquefaction triggering. The greater compressibility of the air bubbles rules the volumetric strains of gassy soils during seismic shaking reducing the build up of the pore water pressure. Mele et al., (2022) verified that, at the laboratory scale, due to lower frequencies of the applied cyclic loads, a non-negligible amount of soil volumetric strains is due to dissolution of air bubbles in the water (εv,diss). The outcomes of some simple compression tests carried out on a two-phase medium made of air/water confirm that such amount cannot be correctly computed with the Henry’s law, which considers the dissolution process of air into water in the hypothesis of continuous air phase. Experimental evidences highlighted that εv,diss is mainly ruled by the continuity of air phase (linked to the chosen experimental procedure), and it exceeds the theoretical previsions when air phase is discontinuous with single bubbles occluded in the fluid phase.
Digital image-based analysis of a small-scale dam failure during wetting
Authors: Morales Gerardo , Pinyol Núria M. , Lloret Antonio
Published: April 2023

The use of digital images and the correlation of them in time is commonly used in geotechnical laboratory experiments to measure surface variables in a non-invasive and massive way. Digital image correlation-based methods provide a measure of the motion of soil. More recently, measurements of the degree of saturation on soil surface using digital images have also been developed, although its application and validation are still limited. This methodology is based on the fact that almost all soils become darker (less light reflective) due to wetting. This article uses image-based analysis techniques to evaluate the behaviour during wetting of a small-scale dam made of compacted fine sand. With the aim of validating the measurements from images, soil moisture sensors were installed in the dam. The tested soil was previously calibrated to determine the correlation of light reflectance and the degree of saturation covering from dry to fully saturated range. Measurements of velocity, displacements, deformations and the degree of saturation in time are evaluated during the experiment based on images recorded in the visual and shortwave infrared (SWIR) light range. The methodology is described step-by-step including camera and lighting system, sample preparation, image acquisition and image analysis. The techniques used allow the changes in the degree of saturation in soil in motion and the failure mechanisms associated with the wetting process to be observed. The results obtained through image analyses show good agreement with the parameters obtained in point measurements with conventional sensors. The results also show some limitations of the method, mainly associated with the accumulation of errors in the tracking of soil particles during large displacements.
Investigation of the hydraulic regime of a desiccated slope under both natural and simulated environmental conditions
Authors: McConnell Emma , Holmes Jessica , Stirling Ross , Davie Colin T. , Glendinning Stephanie
Published: April 2023

Deterioration within desiccated, clay infrastructure embankments can originate from two processes: (A) preferential flow through cracks allowing deeper and faster propagation of wetting fronts, and (B) microstructural degradation, reducing soil water retention capacity. These processes are interrelated, and together act to increase surface layer exposure to intense mechanical weathering and therefore, risk of asset failure. Desiccation induced deterioration is set to intensify under future climate change projections, heightening the need to understand how these processes develop within, and deteriorate, embankment fill over time. To address this, long-term hydrological and desiccation crack monitoring of a large-scale slope, constructed within an outdoor lysimeter, has been carried out under both natural, and simulated, climatic conditions. Initial findings illustrate a highly desiccated slope has the capacity to accept a large volume of storm rainfall prior to crack closure. This volume is set to increase due to the progressive aggregation and reduction in SWR behaviour observed within the slope. The importance of antecedent conditions, both in terms of crack geometry and initial degree of saturation, at the onset of rainfall, additionally proved important as it controls the depth and magnitude of VWC change in the slope. Continued monitoring of the slope will aid our understanding of the temporal evolution of these deterioration processes.
Effects of wetting and drying cycles on the mechanical behaviour of Lightweight Cemented Soils
Authors: Sabatino Filomena , Cuisinier Olivier , Russo Giacomo , Vitale Enza , Nicotera Marco Valerio
Published: April 2023

An experimental investigation on the durability of Lightweight Cemented Soils (LWCS) after wetting and drying cycles was developed, focusing on the evolution of their mechanical response. Wetting and drying cycles were performed in climatic chamber to test their mechanical performance as function of number of cycles and the environmental conditions (50% and 90% of Relative Humidity). Unconfined compression tests and triaxial tests were performed on treated specimens after cycles in dry state. Suction of LWCS samples was measured after mechanical tests. Test results show that the wetting-drying cycles and the variations of suction are responsible for the evolution of LWCS mechanical behaviour. Moreover, strength and stiffness of the treated samples are related to the suction level induced by environmental conditions. The degradation of mechanical behaviour is linked to the number of cycles and to the amplitude of suction variation induced, being the latter responsible for mechanical cement bonding destructuration.
The performance of laterally loaded piles in layered sandy soils under variable degree of saturation
Authors: Hasan Ahmed , Hummadi Rizgar , Azeez Omed
Published: April 2023

This paper investigates the capacity of a single laterally loaded pile in single- and multi-layered sandy soils under dry, unsaturated and saturated conditions for a wide range of void ratios. Two Linear ariable Differential Transformers (LVDT) were employed to measure lateral displacements. For unsaturated tests, on one layer and two layered sandy soils, suction was controlled using the hanging column technique. Two different suction levels were applied to the soils. The results demonstrated that, the capacity of a single laterally loaded pile in single- and multi-layered sandy soils, under unsaturated conditions, were greater than those in dry and saturated conditions for loose, medium and dense states. Comparison between experimental data for unsaturated tests and several proposed mathematical expressions in the literature for calculating the capacity of a single laterally loaded pile in sandy soils showed a significantly good fit between measured and predicted values of the capacity of the piles where Bishop’s stress is used in the expressions instead of effective stress, confirming the importance of inclusion of suction and degree of saturation in mathematical models when unsaturated conditions of soils were investigated.
Hydromechanical characterisation of a highly expansive clay
Authors: Eost Lucy , Gaspar Tiago A.V. , Osman Ashraf S.
Published: April 2023

The hydromechanical properties of a South African expansive clay are reported. In this study,swell potential and swell pressure were assessed by two oedometric approaches, namely, the loading after wetting test and the wetting after loading test. The data indicate that predictions of swell pressure from the two approaches remain similar, whereas greater predictions of heave are obtained for the loading after wetting approach. It is also observed that the magnitude of predicted heave from the loading after wetting test is dependent on the soaking stress considered, with greater swell being obtained for lower soaking stresses. Measurements of primary drying and wetting curves illustrate appreciable hysteresis in the intermediate suction range (≈17 MPa). The discrepancy of this finding with that of a previous study is attributed to differences in fabric. Additionally, when examining the volumetric response of a sample subjected to a drying and wetting path, negligible hysteresis is observed when void ratio is plotted as a function of gravimetric water content. Conversely, when the shrinkage/swell curves are plotted in terms of suction, irreversibly volumetric changes are apparent.
Consideration of microstructure in modelling the hydro-mechanical behaviour of unsaturated soils
Authors: Wu Tianchi , Cleall Peter , Tripathy Snehasis , Cai Guoqing
Published: April 2023

The hydro-mechanical behaviour of unsaturated soils is often highly influenced by the microstructure; therefore, it can be beneficial to consider the effect of microstructure in a hydro-mechanical constitutive model. This paper considers the use of a microstructure-related model that adopts the effective degree of saturation as a microstructural index. The model can be used to reproduce the hydro-mechanical behaviour while the effect of the microstructure is considered. For comparison, a non-microstructuredependent model is also employed. The models are applied to simulate the behaviour of two different soilsand a comparison of the models’ performance in simulating triaxial test behaviour is made. Based on the comparison with experimental results and the non-microstructure-dependent model, it can be concluded thatthe adoption of the effective degree of saturation is beneficial to studying the hydro-mechanical behaviour of unsaturated soils affected by the microstructure.
Homogenization of unsaturated bentonite during hydration
Authors: Gens Antonio , Vasconcelos Ramon , Rodríguez Carlos E. , Vaunat Jean , Villar María Victoria
Published: April 2023

Bentonite barriers are a key component in may designs of deep geological repositories for high level nuclear waste. During the hydration stage, the bentonite undergoes non-uniform changes in dry density that may persist even after reaching a fully saturated state. Since dry density controls the properties of the bentonite that ensure the functions of safety of the barrier, the potential of bentonite for homogenization or otherwise is a matter of high relevance. The paper presents the results and the analyses of two hydration tests on initially heterogenous samples, especially designed to explore the phenomena and processes underlying the homogenisation of bentonite materials. The formulation and constitutive model used in the analyses are briefly presented followed by a description of the tests. Subsequently, the experimental dataobtained from the tests are discussed together with the results of the hydromechanical analyses performed. Particular attention is given to the degree of homogenization of the specimens achieved at the end of the tests. The simulations have resulted in a very satisfactory agreement with test observations, especially egarding the final state of the samples, thus enhancing the confidence in the numerical tool employed.
Extending modified Cam-Clay to unsaturated soils by incorporating a scaled stress variable
Authors: Bruno Agostino Walter , Pitso Talenta , Lalicata Leonardo Maria , De Paoli Adrian , Gallipoli Domenico
Published: April 2023

This paper extends the modified Cam-Clay model to describe the behaviour of unsaturated soils by replacing the effective stress with the scaled stress. The scaled stress accounts for the mechanical effect of capillarity by factoring Bishop’s stress with a power function of degree of saturation. The extendedmodified Cam-Clay model postulates the existence of a yield curve in the mean scaled stress 𝑝̅– deviatoric scaled stress 𝑞̅ plane. Coherently with the modified Cam-Clay model, the stress-strain behaviour is predicted by means of an elastic law inside the yield curve. As the scaled stress state evolves onto the yield curve, the behaviour becomes elasto-plastic and this is modelled by a plastic flow rule combined with a volumetric hardening law. The extended modified Cam-Clay model is then validated against experimental data published in the literature. Results show that the proposed approach is capable of well predicting the mechanical behaviour of unsaturated soils during triaxial loading. Future work will be directed at further validating the present formulation along different stress paths as well as accounting for the combined effect of partial saturation and cementation within a critical state framework based on bounding surface plasticity.
Finite element modelling of unsaturated soils using a modified version of the Barcelona Basic Model
Authors: Laera Anita , Bui Tuan Anh , Brasile Sandro
Published: April 2023

In this paper, unsaturated soil behaviour is numerically simulated using a modified version of the Barcelona Basic Model. The model has been implemented as a User-Defined Soil Model (UDSM) in the finite element code PLAXIS. Unlike the original formulation based on net stress ([1]), this model isformulated based on the well-known Bishop’s effective stress, with suction as an additional stress variable. Furthermore, a non-associated flow rule and the dependency on Lode’s angle proposed by [2] are incorporated. The Soil Water Characteristic Curve (SWCC) follows the Van Genuchten model ([3]). First, the simulation of laboratory tests along different stress paths and levels of suction are compared againstexperimental data. Then, an unsaturated soil embankment subject to a time-dependent precipitation is simulated by means of a fully coupled flow-deformation analysis. The results show the capability of the model to reproduce the main features of unsaturated soil behaviour both at material point level and inboundary value problems.
A fully coupled hydro-mechanical model for the analysis of partially saturated multiphase geo-structures using the bounding surface plasticity
Authors: Samimi Soodeh , Gharehdaghi Mahnoush , Shahbodagh Babak , Khalili Nasser
Published: April 2023

This paper presents a fully coupled plasticity model for the rigorous analysis of fluid flow and solid skeleton deformation in variably saturated porous media. The flow deformation behaviour of unsaturated soils is described through the simultaneous solution of governing partial differential equations, including the equilibrium equation and the continuity equations of pore fluids. The coupling between solid and fluid phases is established based on the effective stress concept with the effective stress parameter as a function of suction. The elasto-plastic behaviour of geomaterials is formulated using the bounding surface theory. The fully coupled flow deformation framework along with the UNSW bounding surface constitutivelaw are implemented into COMSOL Multiphysics commercial software to simulate the results of several laboratory tests conducted on soils with different degrees of saturation under various drainage conditions and loading paths. The close agreement between the numerical solutions and experimental data from the literature indicates the good performance of this new elastic-plastic unsaturated model and emphasises its capability to capture the different characteristic features of response of soils with a variety of saturation degrees and over-consolidation ratios.
Monitoring activities for the preservation of an Etruscan hypogeum in unsaturated soil mass
Authors: Cecconi Manuela , Melelli Laura , Russo Giacomo , De Angelis Alessio , Carbone Paolo , Cencetti Corrado , Di Maio Rosa , Turchetti Maria Angela , Pane Vincenzo
Published: April 2023

A geotechnical monitoring campaign and a site investigation have been recently planned and undertaken aiming at the preservation and protection of the “Palazzone” Etruscan necropolis, an archaeological site dated back to Hellenistic period located 4 km from the city of Perugia, along the southeastern margin of the hill where the town is settled. The site includes some beautiful and monumental cavities, among them, the Volumni Hypogeum. The majority of the graves are underground cavities excavated in partially saturated alluvial soil deposits. Their inspection reveals the geological features and the depositional structures. The groundwater table is located about 35 m below the ground surface. Due to the difficulties of soil-sampling inside the ancient cavities, only limited portions of the material were retrieved for conventional laboratory tests, although not enough for a geotechnical characterization. On the other hand, XRD analyses and MIP tests were performed. The obtained results allowed to recognize the relevant contribution of soil suction to the stability conditions of the lateral walls and the ceiling of the cavities, which is complementary to the weak cementation characterizing the soil mass. This important information supports the conservation strategy of the monument, which has as its primary tool the monitoring of environmental conditions, aimed at maintaining the unsaturated conditions of the soil mass.
A parametric study on the hydromechanical properties of claystone/bentonite mixtures
Authors: Tyri Danai , Djeran-Maigre Irini , Robinet Jean-Claude , Zghondi Jad
Published: April 2023

Mixtures of crushed excavated COx claystone and bentonite are considered as a potential backfill solution for the French disposal concept of radioactive waste. In the present work, the hydro-mechanical behaviour of claystone/sodium bentonite mixtures was experimentally investigated for various bentonite contents (≤40% in total mass) and densities. Demineralized, site water and cementitious alkaline solution were used. Test on mixtures physicochemical properties showed that Plasticity Index (PI) and Free Swelling Index (FSI) values increase with bentonite content. Introducing bentonite in the mixture induces to lower density for the same compaction energy. No clear impact of the cementitious solution was observed compared to the site water. The expected swelling pressure increase upon bentonite increment was obtained. The effect was more important at higher densities. Mixtures primary wetting, resulted in lower swelling pressure.
Determination of wetting soil water characteristics curve from disk infiltrometer measurements
Authors: Naik Aparimita Priyadarshini , Pekkat Sreeja
Published: April 2023

A wetting soil water characteristic curve (SWCCw) is necessary for understanding and interpreting the re-distribution of infiltrated rainwater, percolation rate, and contaminant transport. Direct determination of SWCCw is tedious and needs destructive sampling and invasive sensor installation. This study demonstrates an indirect method for determining SWCCw based on infiltration measurements using a mini disc infiltrometer (MDI). Under controlled initial conditions, infiltration tests were conducted, coupled with real-time soil moisture and matric potential measurements using sensors. Sensor data facilitated assessment and cross-verification of SWCCw indirectly determined from MDI measurements. The indirect estimation involved inverse analysis and optimization of SWCCw parameters (α and n of the van Genuchten model) based on measured cumulative infiltration (CI) -versus-time response along with the knowledge of final volumetric water content (VWCf). The optimized SWCCw from MDI-infiltration matched the sensor-measured SWCCw reasonably well. The statistical tests using ANOVA proved that the CI measurements from MDI, together with VWCf information, are reliable input for inverse estimation of SWCCw and its parameters. Based on a realistic wetting process in the unsaturated zone beneath the disc infiltrometer, this study demonstrates the utility of a compact MDI for a quick, non-destructive measurement of SWCCw.
A new way to determine the indicators of vertical and horizontal of a subway car
Authors: Rahimov R. , Boronenko Yu. , Tretyakov A. , Sultonov Sh.
Published: April 2023

The issues of measuring the coefficients of vertical and horizontal dynamics of a subway car during running dynamic tests are reviewed. The theoretical research of bogie frame loading by finite element method has been done. Analysis of complex calculation outcomes and stress distribution diagrams on bogie frame under the action of vertical, longitudinal, and lateral forces has allowed defining the place of strain gauges installation on the elements of the bogie and the signal processing method for measuring vertical and lateral forces acting on bogie frame of the subway car. The new measuring circuit with strain gauges connected in two full bridges with a four-wire connection scheme will provide simultaneous measurement of vertical and lateral forces acting on the subway car bogie frame. The running tests on the evaluation of dynamic qualities of subway car model 81-714Uz confirmed the effectiveness of the developed measuring scheme for determining the indicators of vertical and horizontal dynamics of a subway car.
Current status of water objects in Russia
Authors: Chernikov N.A. , Kudryavtsev A.V.
Published: April 2023

The issues of the current state of water bodies in the Russian Federation are considered and their comparative characteristic with other countries, mainly Western European ones, is given. By a resolution adopted by the UN General Assembly in 2018, a system of global indicators for achieving the Sustainable Development Goals and targets for the period up to 2030 was approved, and one of these targets is devoted to the state of water bodies. Despite large water resources, Russia already has serious problems with the quality of water in water bodies and the degree of financing of water protection measures. The water quality of such rivers as the Neva and the Volga was very high a few decades ago, but now it causes serious concerns. For some ingredients, the concentration of pollutants exceeds the maximum allowable concentrations hundreds of times. Since the 1990s and up to the present time, the relative financing of water protection measures (as a percentage of GDP) in the Russian Federation has been constantly decreasing. The efficiency of the use of financial resources is also decreasing.
Green principles of ecological safety of transport construction
Authors: Shestakova Ekaterina , Shestakov Pavel
Published: April 2023

The current trend toward the use of 3D concrete printing represents a vector for green financing of innovative transportation projects and a shift from traditional construction to additive manufacturing and a closed-loop economy. The potential impact of additive technology in the field of transport infrastructure is expected to be greater than in any other, due to the scale of construction printing and its environmental potential to ensure the environmental safety of transport construction at the global, regional and local levels, which appears to be a relevant interdisciplinary research area. The article analyzes the transition to a "green economy," including the introduction of additive technologies and the rational use of construction resources. The article gives proposals for energy-efficient and ecological green construction of high-speed railways and provides a rationale for the use of additive technologies using 3D-printed noise protection walls made of eco-concrete (green concrete, geo-concrete). The main recommendations on the choice of structures, optimal for the implementation of active noise protection measures on high-speed railways and artificial constructions are given. Presented the work of PSTU students of the Faculty of Transport Construction on the subject of 3D printing of noise protection panels with different acoustic performance. Modern architectural solutions were made with the preparation of a feasibility study on the implementation of innovations and the development of green design competencies.
Geodetic network for the construction of the high-speed railway line
Authors: Kanashin Nikolay
Published: April 2023

Geodetic support for construction and operation of high-speed railways requires high-precision geodetic work both at the construction stage and during operation of the structure. Geodetic separation network, being the basis of mainline construction, requires special care and accuracy in measurements for its creation. The analysis of studies carried out in this field shows their insufficiency or incorrectness, and the comparison of current rules and regulations documents shows their contradiction. In the article, based on the results of existing scientific works, on the basis of the allowable standard values of outstanding lateral accelerations, the necessary accuracy of building a marking network for the construction of a railway line with speeds up to 400 km/h is calculated. On the basis of the analysis of existing regulatory documents of various countries engaged in high-speed rail traffic, the correctness of the obtained result has been proved. The imperfection of the Russian normative base in the field of construction of such objects is shown. Based on the findings, practical recommendations are given on methods for constructing a planned network for the construction of a high-speed highway and fixing its points, which can significantly reduce the cost and intensity of work on its creation, as well as directions for further necessary research in the field of geodetic support for the construction of high-speed highways.
Programs with programs to take water from the river without dams
Authors: Uljayev Farokhiddin , Yuldoshev Khushnudbek , Abdullaeva Barno
Published: April 2023

In the arid areas of the river itself, the direction of flow is characterized by changes depending on its hydrological regime. As a result of these changes, the flow can be branched into several streams and the flow can be distributed differently in terms of quantity. As the river passes through lightly washed soils, these streams have different depths, and its hydraulic elements and river morphometry can vary at different intensities. Changes in hydraulic resistance as a result of such changes can affect the water permeability of streams. It should be noted that, depending on the form of morphometry, the roughness of the stream and the shoreline may vary at the same constant size of depth. This could be the Karshi Main and Amu Bukhara Mashina canals, which receive the most dam-free water from the Amudarya to the irrigated areas of the Republic of Uzbekistan. In these catchment areas, rapid washing of riverbeds, uneven distribution of flow velocity, and the constant distance of the stream from the dam intake facility away from the main intake facility complicate operating conditions and reduce the amount of water required to enter the canal during the growing season.
Restoration of underground water-carrying structures damaged by external non-stationary impacts
Authors: Perminov Nirolay
Published: April 2023

Object and purpose of the study: Underground aquiferous point and linear structures operated in difficult ground conditions lose their structural safety as a result of the influence of external forces and the environment. It is important to establish the features of the operation of underground aquifers and communications in an inhomogeneous enclosing soil massif, taking into account the interaction of structures with the ground in case of non-stationary force impacts and environmental impacts with an assessment of their structural safety. Methods: The use of analytical and experimental research methods to evaluate the work of structures in the soil mass, taking into account force influences and environmental influences. Results: The features of interaction of the housing of a collapsible pipe with a soil mass with a multidirectional horizontal component of a non-stationary load are established. The negative impact of the combination of the multidirectional impact of the power load and internal hydrostatic pressure on the structural safety of the housing of a prefabricated underground structure is shown. Practical significance and conclusions: The results obtained on the picture of the stress-strain state of an inhomogeneous enclosing soil massif allowed us to establish the nature and boundaries of the safe operation of structures and to make suggestions on the choice of ways to strengthen and protect underground structures, taking into account their operating conditions.
Design of rockfall protection structures
Authors: Lesov Kuvandyk , Ortikboyev Muslim , Yuldasheva Nafisa
Published: April 2023

The article analyses the rockfall phenomena that disrupt the continuity and safety of railway traffic in mountainous areas. The reasons causing rockfall phenomena are given. Recommendations are given for the choice of rockfall-proof structures design to ensure safe operation of facilities against rockfall processes depending on a number of initial parameters.
Theoretical essentials for designing viscous liquid pumping systems in the conditions of the Arctic region
Authors: Kim Konstantin , Ivanov Sergey , Khismatulin Marat
Published: April 2023

The purpose is the creation of a scientifically based solution for the design of hermetic electromechanical converters adapted to existing pipelines, as well as those under construction and development. These pipelines meet the energy efficiency requirements and operate in the conditions of the Arctic region. Methods: methods of mathematical analysis, numerical methods, and methods of mathematical programming were used as the main mathematical means. The CFD design package of Ansys Maxwell was used. Research results: we showed that an increase of the efficiency of the system of technological transportation of petroleum products at low temperatures is possible through the use of electromechanical devices that combine the functions of heating and pumping the working liquid. We solved the field problem based on the analytical calculations carried out by a computer. This allowed us to determine the distribution of eddy current density in the structural elements of these devices responsible for creating pressure and heating the pumped petroleum products. The importance of the electrical parameters of the secondary windings has been confirmed numerically and experimentally. The hydraulic characteristics, mechanical losses, volumetric losses and efficiency are determined. Taking into account the outcomes of theoretical studies the experimental sample of the sealed electromechanical converter with the specified physical and chemical characteristics was created at Emperor Alexander I St. Petersburg State Transport University. Practical relevance: the obtained analytical formulas can be used at the development of the systems for pumping viscous liquids at low temperatures using the sealed electromechanical converters which helps to reduce the installed power of energy equipment without degrading the values of technological indicators.
On the causes of electrothermal destruction of fiber-optic communication lines placed on the structures of AC overhead wires
Authors: Osipov V.A.
Published: April 2023

The paper analyses the impact of the electromagnetic field of an alternating current catenary section on a fiber-optic cable suspended on the structures of the catenary system or on the overhead wires of the Centralised Traffic Control (CTC). Based on this calculation, conclusions have been made about the negative impact of alternating current electric fields with high vorticity.
Research corrosion of cements with a new hydraulic additive
Authors: Kabulova Lola , Orazimbetova Gulistan , Abdullaeva Barno
Published: April 2023

Based on the above studies, the following conclusions can be made: The introduction of hydraulic additives into Portland cements increases their sulfate resistance, especially when cements have higher C3A content. Cements with 30% tuffite give better strength than those with 20% tuffite. The least aggressive for pozzolanic Portland cements are 5% Na2SO4 solution, the most aggressive is 3% MgSO4 solution, in which cements with hydraulic additives were more resistant than pure Portland cements, which is in agreement with the data of other researchers. For sulfate-resistant pozzolanic Portland cement maximum C3A content in the original Portland cement can be increased up to 8%.
Changes in the electronic structure of the Si surface as a result of ion implantation
Authors: Donaev S.B. , Ziyamukhamedova U.A. , Kenjaeva M. , Shirinov G.M. , Rakhimov A.M. , Abduvayitov A.A.
Published: April 2023

The composition, structure, and physicochemical properties of the surface and near-surface layers of silicon doped with low-energy (E0<5 keV) Ba+ and O2+ ions have been studied using a set of photoelectron and secondary electron spectroscopy methods. It has been established that in the process of ion implantation, chemical bonds are formed between the atoms of the alloying element and the matrix, the width of the energy bands and the density of electronic states in the bands change.