bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluating the functional, sexual and seasonal variation in the chemical constituents from feces of adult Iberian wolves (Canis lupus signatus)
Authors: Barja Isabel , Piñeiro Ana , Ruiz-González Aritz , Caro Amaia , López Pilar , Martín José
Published: April 2023

Chemical signals deposited in feces play an important role in intraspecific and interspecific communication of many mammals. We collected fresh feces of adult wolves from wild breeding groups. All samples visually identified as belonging to wolves were subsequently identified to species level by sequencing a small fragment of mtDNA and sexed typing DBX6 and DBY7 sex markers. Using gas chromatography-mass spectrometry (GC–MS), we identified 56 lipophilic compounds in the feces, mainly heterocyclic aromatic organic compounds, such as indole or phenol, but also steroids, such as cholesterol, carboxylic acids and their esters between n-C4 and n-C18, aldehydes, alcohols and significant quantities of squalene and α-tocopherol, which would increase the chemical stability of feces on humid substrates. There was variability in the number and proportions of compounds between sexes, which could be indicative of their function as chemical signals. We also found variability in different reproductive states, especially in odorous compounds, steroids and α-tocopherol. Feces with a presumed marking function had higher proportions of α-tocopherol and steroids than feces with non-marking function. These compounds could be involved in intragroup and intergroup communication of wolves and their levels in feces could be directly related with the wolf’s sex and physiological and reproductive status.
Development of sustainable strontium ferrite graphene nanocomposite for highly effective catalysis and antimicrobial activity
Authors: Mayani Suranjana V. , Bhatt Sandip P. , Mayani Vishal J. , Sanghvi Gaurav
Published: April 2023

Graphene oxide (GO) has layered structure with carbon atoms that are highly coated with oxygen-containing groups, increasing the interlayer distance while simultaneously making hydrophilic atomic-thick layers. It is exfoliated sheets that only have one or a few layers of carbon atoms. In our work, Strontium Ferrite Graphene Composite (SF@GOC) has been synthesized and thoroughly characterized by physico-chemical methods like XRD, FTIR, SEM–EDX, TEM, AFM, TGA and Nitrogen adsorption desorption analysis. A very few catalysts have been manufactured so far that are capable of degrading Eosin-Y and Orange (II) dyes in water by heterogeneous catalytic method. The current study offers an overview of the recyclable nanocomposite SF@GOC used in mild reaction conditions to breakdown the hazardous water pollutant dyes Eosin-Y (96.2%) and Orange (II) (98.7%). The leaching experiment has demonstrated that the use of the transition metals strontium and iron have not result in any secondary contamination. Moreover, antibacterial and antifungal assay have been investigated. SF@GOC has shown greater activity with bacterial and fungal species while compared with GO. FESEM analysis shows that the bactericidal mechanism for SF@GOC is same in both gram-negative bacteria. The difference in the antifungal activity among the candida strains can be correlated with the movement of ions release (slower and faster) of synthesized nanoscrolls in SF@GOC. In comparison to previous reports, this new environmentally safe and novel catalyst showed substantial degrading activity. It can also be applied to new multifunctional processes such as in the fields of composite materials, solar energy, heterogeneous catalysis and biomedical applications.
Highly efficient graphene terahertz modulator with tunable electromagnetically induced transparency-like transmission
Authors: Kim Myunghwan , Kim Seong-Han , Kang Chul , Kim Soeun , Kee Chul-Sik
Published: April 2023

Graphene-based optical modulators have been extensively studied owing to the high mobility and tunable permittivity of graphene. However, weak graphene-light interactions make it difficult to achieve a high modulation depth with low energy consumption. Here, we propose a high-performance graphene-based optical modulator consisting of a photonic crystal structure and a waveguide with graphene that exhibits an electromagnetically-induced-transparency-like (EIT-like) transmission spectrum at terahertz frequency. The high quality-factor guiding mode to generate the EIT-like transmission enhances light-graphene interaction, and the designed modulator achieves a high modulation depth of 98% with a significantly small Fermi level shift of 0.05 eV. The proposed scheme can be utilized in active optical devices that require low power consumption.
Proteomic data and structure analysis combined reveal interplay of structural rigidity and flexibility on selectivity of cysteine cathepsins
Authors: Tušar Livija , Loboda Jure , Impens Francis , Sosnowski Piotr , Van Quickelberghe Emmy , Vidmar Robert , Demol Hans , Sedeyn Koen , Saelens Xavier , Vizovišek Matej , Mihelič Marko , Fonović Marko , Horvat Jaka , Kosec Gregor , Turk Boris , Gevaert Kris , Turk Dušan
Published: April 2023

Addressing the elusive specificity of cysteine cathepsins, which in contrast to caspases and trypsin-like proteases lack strict specificity determining P1 pocket, calls for innovative approaches. Proteomic analysis of cell lysates with human cathepsins K, V, B, L, S, and F identified 30,000 cleavage sites, which we analyzed by software platform SAPS-ESI (Statistical Approach to Peptidyl Substrate-Enzyme Specific Interactions). SAPS-ESI is used to generate clusters and training sets for support vector machine learning. Cleavage site predictions on the SARS-CoV-2 S protein, confirmed experimentally, expose the most probable first cut under physiological conditions and suggested furin-like behavior of cathepsins. Crystal structure analysis of representative peptides in complex with cathepsin V reveals rigid and flexible sites consistent with analysis of proteomics data by SAPS-ESI that correspond to positions with heterogeneous and homogeneous distribution of residues. Thereby support for design of selective cleavable linkers of drug conjugates and drug discovery studies is provided.
Biophysical flocculation reduces variability of cohesive sediment settling velocity
Authors: Ye L. , Penaloza-Giraldo J. A. , Manning A. J. , Holyoke J. , Hsu T.-J.
Published: April 2023

Biophysical cohesion, introduced predominantly by Extracellular Polymeric Substances (EPS) during mineral flocculation in subaqueous environments, plays important role in morphodynamics, biogeochemical cycles and ecosystem processes. However, the mechanism of how EPS functioning with cohesive particles and affects settling behaviors remain poorly understood. We measure initial flocculation rate, floc size and settling velocity of mineral and artificial EPS (Xanthan gum) mixtures. Combining results from these and previous studies demonstrate coherent intensification of EPS-related flocculation compare with those of pure mineral and oil-mineral mixtures. Importantly, the presence of EPS fundamentally changes floc structure and reduces variability of settling velocity. Measured data shows that ratios of microfloc and macrofloc settling velocity for pure mineral flocs is 3.9 but greatly reduced to a lowest value of 1.6 due to biological EPS addition. The low variability of settling velocity due to EPS participation explains the seemingly inconsistent results previously observed between field and laboratory studies.
Immobilization of Ni(ii) complex on the surface of mesoporous modified-KIT-6 as a new, reusable and highly efficient nanocatalyst for the synthesis of tetrazole and pyranopyrazole derivatives
Authors: Darabi Mitra , Nikoorazm Mohsen , Tahmasbi Bahman , Ghorbani-Choghamarani Arash
Published: April 2023

Anchoring of Ni(ii) complex onto the surface of mesoporous KIT-6 modified under mild reaction conditions as a highly efficient and reusable nanocatalyst for the synthesis of 5-substituted tetrazoles and pyranopyrazoles.
Photomechanical response under physiological conditions of azobenzene-containing 4D-printed liquid crystal elastomer actuators
Authors: Ceamanos Lorena , Mulder Dirk J. , Kahveci Zehra , López-Valdeolivas María , Schenning Albert P. H. J. , Sánchez-Somolinos Carlos
Published: April 2023

This work analyses the photomechanical work performance of 4D-printed liquid crystal elastomers under physiological conditions in PBS media.
Quantification of an effective charge injection barrier in non-fullerene-based organic photodetectors
Authors: Chen Yuting , Li‡ Jingwen , Xie Yuan , Chen Yihui , Wu Hongbin
Published: April 2023

Studies on the origin of dark current in organic photodetectors reveal that the charge injection from the contact to the active layer via subgap traps is the dominant source of dark current once the effective injection is correctly described.
Bioceramic and polycationic biopolymer nanocomposite scaffolds for improved wound self-healing and anti-inflammatory properties: an in vitro study
Authors: Manjubaashini N. , Bargavi P. , Balakumar S.
Published: April 2023

Chitosan–45S5 bioglass nanocomposite scaffolds for enhanced wound healing and preventing inflammatory cytokines.
Unveiling the role of microwave induction on V2O5@AC catalysts with enhanced activity for low temperature NH3-SCR reaction: an experimental and DFT study
Authors: Cheng Jie , Xu Ruinian , Song Liyun , He Hong , Chen Biaohua
Published: April 2023

The 3V2O5@AC-300 catalyst exhibits excellent catalytic performance as a result of abundant oxygen vacancies and superior redox ability.
Role of aggregates and microstructure of mixed-ionic–electronic-conductors on charge transport in electrochemical transistors
Authors: LeCroy Garrett , Cendra Camila , Quill Tyler J. , Moser Maximilian , Hallani Rawad , Ponder James F. , Stone Kevin , Kang Stephen D. , Liang Allen Yu-Lun , Thiburce Quentin , McCulloch Iain , Spano Frank C. , Giovannitti Alexander , Salleo Alberto
Published: April 2023

OMIECs undergo structural rearrangements to accommodate ions and electronic charge carriers during which percolating networks are formed for efficient electronic charge transport.
Unveiling re-entrant phase behavior and crystalline–amorphous interactions in semi-conducting polymer:small molecule blends
Authors: Peng Zhengxing , Ade Harald
Published: April 2023

It is revealed that the re-entrant phase behavior of the conjugated polymer:small molecule systems is indeed a result of thermodynamics. The composition difference (Δϕ) between liquidus and binodal reflects the crystalline–amorphous interaction.
Enantioselective total syntheses of (−)-cephalotaxine and (−)-amathaspiramide F through a key Ir/Cu dual catalysis
Authors: Sheng Peng-Zhen , Li Lu-Lu , Zhang Hongbin , Wei Kun , Yang Yu-Rong
Published: April 2023

Ir/Cu dual-catalysed allylation constructs vicinal tertiary and N-substituted quaternary stereogenic centres of two alkaloids in a single operation.
Photocatalytic decarboxylative selenocyanation of 2-aryloxy and 2-aryl carboxylic acids with N-selenocyanatophthalimide
Authors: Gao Yong , Hua Ruirui , Yin Hongquan , Chen Fu-Xue
Published: April 2023

A visible-light-induced decarboxylative radical selenocyanation reaction of aliphatic carboxylic acids with the electrophilic N-selenocyanatophthalimide has been developed.
Visible light driven reform of wasted plastics to generate green hydrogen over mesoporous ZnIn2S4
Authors: Zheng Yeqin , Fan Ping , Guo Rongjie , Liu Xiaohui , Zhou Xiantai , Xue Can , Ji Hongbing
Published: April 2023

A mesoporous ZnIn2S4 photocatalyst shows notable activity for photoreforming of PLA, PET and PU to generate small organic chemicals and H2 fuel under simulated sunlight at room temperature.
Folic acid–maltodextrin polymer coated magnetic graphene oxide as a NIR-responsive nano-drug delivery system for chemo-photothermal synergistic inhibition of tumor cells
Authors: Gong Tao , Wang Xiaoyu , Zhu Huirui , Wen Chaochao , Ma Qing , Li Xiaoning , Li Meining , Guo Rui , Liang Wenting
Published: April 2023

A multifunctional nanocomposite, MGO-MDP-FA, was designed to be an efficient chemo-photothermal therapeutic platform with targeted drug delivery DOX, NIR triggered drug release, excellent stability and high photothermal conversion efficiency.
A two-photon fluorescent probe for formaldehyde detection and regeneration in living cells
Authors: Song Qi , Liu Zhiqiang , Niu Jie , Zheng Bowen , Hao Jingcheng , Jiang Jie
Published: April 2023

A two-photon excited fluorescent probe CMB-1 has been rationally developed based on a new sensing mechanism for the detection and regeneration of formaldehyde in living cells with minimal influence on its native homeostasis and local concentration.
Development of a synthesis strategy for sulfamethoxazole derivatives and their coupling with hydrogel microparticles
Authors: Riedl Veronika , Portius Matthias , Heiser Lara , Riedl Philipp , Jakob Torsten , Gehring Rosa , Berg Thorsten , Pompe Tilo
Published: April 2023

For perspective biosensing applications, we demonstrate the synthesis of sulfamethoxazole derivatives and their site-directed coupling to microfluidic generated hydrogel microparticles.
Tri-cationic copolymer hydrogels with adjustable adhesion and antibacterial properties for flexible wearable sensors
Authors: Sun Xiangbin , Liu Xiaoqing , Huang Peng , Wang Zeyuan , He Yufeng , Song Pengfei , Wang Rongmin
Published: April 2023

A comprehensive hydrogels with zwitterions was successfully prepared. It showed excellent adjustable adhesion and antibacterial activity, and could be applied to accurately monitor movements in the human body as flexible wearable sensors.
Yersinia pestis and plague in the 21st century: learning from a distant past
Authors: Mas Fiol Guillem , Demeure Christian , Guern Anne-Sophie Le , Pizarro-Cerdá Javier
Published: April 2023

Plague is an often fulminant and fatal disease caused by the bacterial pathogen Yersinia pestis. Three major historical plague pandemics have heavily influenced human societies, and recent evidence demonstrates that plague has also influenced human biology. Plague is still endemic in several continents and remains a potential public health risk. In this article, we examine the current situation of plague around the world and the different players that participate in plague ecosystems. We discuss in particular the recent research that allows us to understand plague in pre-historical times, as well as how past pandemics have modulated the evolution of human immune genes. We also highlight future challenges that await us in the study of this deadly but fascinating disease.
Two‐stage approach for cooperative multi‐vehicle localization using integrated measurements
Authors: Shin Vladimir , Cervantes Tito Jehu Ludena , Kim Yoonsoo
Published: April 2023

In this article, the distributed filtering of absolute and relative measurements for the cooperative localisation of multiple vehicles is investigated. A novel two‐stage approach that uses two unbiased cooperative filters for the sequential processing of integrated measurements is proposed. The first filter sequentially estimates each vehicle state by replacing extra neighbouring states with corresponding estimates obtained only from absolute measurements and by adding relative measurements. The second filter considers extra neighbouring states as auxiliary coloured noise. The proposed filters have low communication loads and computational complexity because of the sequential processing of the absolute and relative measurements. Unlike existing cooperative filters, the proposed two‐stage structure makes the filters robust against the presence of unreliable links between neighbouring vehicles. We present simulation results demonstrating the effectiveness and accuracy of the proposed filters when applied to vehicles performing two‐dimensional manoeuvres in three network topologies: a ring, line, and mesh.
A 3D view of dwarf galaxies with Gaia and VLT/FLAMES
Authors: Tolstoy Eline , Skúladóttir Ása , Battaglia Giuseppina , Brown Anthony G. A. , Massari Davide , Irwin Michael J. , Starkenburg Else , Salvadori Stefania , Hill Vanessa , Jablonka Pascale , Salaris Maurizio , van Essen Thom , Olsthoorn Carla , Helmi Amina , Pritchard John
Published: April 2023

We present a new homogeneous survey of VLT/FLAMES LR8 line-of-sight radial velocities (vlos) for 1604 resolved red giant branch stars in the Sculptor dwarf spheroidal galaxy. In addition, we provide reliable Ca II triplet metallicities, [Fe/H], for 1339 of these stars. From this combination of new observations (2257 individual spectra) with ESO archival data (2389 spectra), we obtain the largest and most complete sample of vlos and [Fe/H] measurements for individual stars in any dwarf galaxy. Our sample includes VLT/FLAMES LR8 spectra for ∼55% of the red giant branch stars at G < 20 from Gaia DR3, and > 70% of the brightest stars, G < 18.75. Our spectroscopic velocities are combined with Gaia DR3 proper motions and parallax measurements for a new and more precise membership analysis. We look again at the global characteristics of Sculptor, deriving a mean metallicity of ⟨[Fe/H]⟩ = −1.82 ± 0.45 and a mean line-of-sight velocity of ⟨vlos⟩ = + 111.2 ± 0.25 km s−1. There is a clear metallicity gradient in Sculptor, −0.7deg dex−1, with the most metal-rich population being the most centrally concentrated. Furthermore, the most metal-poor population in Sculptor, [Fe/H]<  − 2.5, appears to show kinematic properties distinct from the rest of the stellar population. Finally, we combine our results with the exquisite Gaia DR3 multi-colour photometry to further investigate the colour-magnitude diagram of the resolved stellar population in Sculptor. Our detailed analysis shows a similar global picture as previous studies, but with much more precise detail, revealing that Sculptor has more complex properties than previously thought. This survey emphasises the role of the stellar spectroscopy technique and this galaxy as a benchmark system for modelling galaxy formation and evolution on small scales.
Analysis of climate change impacts on the shrinkage-swelling phenomenon of clayey soils to adapt infrastructures
Authors: Ighil Ameur Lamine
Published: April 2023

As a tendency in France, the well-known shrinkage-swelling phenomenon of clayey soils intensifies naturally and durably under climate change effects after the severe droughts happened post 2015. More than 10.4 million houses are highly exposed to this phenomenon and the new national zoning shows that high or medium exposure now concerns 48% of the metropolitan soils. Roads are also severely impacted by the shrinkage-swelling phenomenon through damage characterized most often by longitudinal cracks close to the edges and very significant deformations that can be a danger for the safety of users. The aim of this research is first to understand how the natural unsaturated clay soils shrink and swell under numerous drying-wetting cycles using several devices at the laboratory scale. The second approach consist of several in situ experimentations of different techniques to reduce the shrinkage-swelling impact on unsaturated clay soils. The first results show that at the laboratory scale, the unsaturated clay soils can be significantly affected after some drying-wetting cycles. In the other hand, in situ monitoring results show that some techniques allow clay soils to save their hydromechanical properties at a hydric equilibrium state which can reduce settlement deformations. The main goal of these research works is to better understand how the shrinkage-swelling phenomenon of clayey soils evolves under climate change in order to develop the new solutions allowing the adaptation of the infrastructures.
Evaluation of the Unsaturated Shear Strength Parameters of Compacted, Heaving Soil Using Geotechnical Properties
Authors: Fondjo Armand Augustin , Theron Elizabeth , Ray Richard P.
Published: April 2023

Abstract The shear strength is a fundamental property of soil material under structural loads. The determination of shear strength properties of unsaturated soils is challenging and time-consuming. Geotechnical predictive models can be utilized to assess the unsaturated shear strength of heaving soil. This study attempts to propose predictive models to evaluate the unsaturated shear strength parameters of compacted heaving soil. These parameters include the angle of internal friction associated with the net normal stress (ϕ'), angle indicating the rate of increase in shear strength with respect to a change in matric suction (ϕb), and effective cohesion (c'). The geotechnical properties of soils were assessed through laboratory tests such as particle size distribution, consistency limits, specific gravity, modified Proctor compaction test, swelling test, suction test, and advanced triaxial testing. Multivariate analysis was conducted using NCSS 12 software to design the models. The validation of models includes the determination coefficient, probability value, comparing experimental values with predicted values, and comparing the developed models with other model found in recent literature. The models engineered in this study can estimate the unsaturated shear strength parameters of compacted heaving soil with acceptable precision.
Implementation and validation of pressure-dependent gas permeability model for bentonite in FEM code Thebes
Authors: Gupta Abhishek , Abed Ayman , Sołowski Wojciech T.
Published: April 2023

In an Engineered Barrier System of a nuclear waste repository, gas migrates through: a) diffusion/advection of dissolved gases, b) two-phase continuum flow, c) dilatant pathway flow and d) single-phase gas flow through macro-fractures in the soil. The gas production rate and the corresponding gas pressure accumulation affect the clay material behaviour and its properties such as air entry value. For the safe design of the EBS system, computational models need to account for the identified transport mechanisms. This study presents an enhancement in the finite element code Thebes [1, 2] that replicates the observed increase in permeability at higher gas pressures, e.g. due to pore dilatancy and gas fracture as proposed by Xu et al. [3]. The formulation links permeability to gas pressure and threshold/critical pressure. For model validation, the study utilizes a gas injection experiment carried out in IfG (Institute for Rock Mechanics, Germany) on Opalinus Clay [4]. The results show a good fit against the measurements while giving insight into gas flow through clays.
Field and laboratory measurements of shear wave velocity in unsaturated soils
Authors: Abuawad Tareq , Miller Gerald , Muraleetharan Kanthasamy
Published: April 2023

Shear wave velocity measurements in soil are important for assigning site soil profiles to seismic site classes and for calculating other dynamic soil properties. The seismic cone penetration test (SCPT) is commonly used to determine shear wave velocity profiles in the field. In the laboratory, bender elements provide an easy means to measure shear wave velocity of soil specimens from discrete depths. In this study, shear wave velocity measurements obtained from unsaturated soil profiles in the field and on field samples in the laboratory under similar stress conditions were analyzed and compared. Additionally, the influence of seasonal changes on the behavior of shear wave velocity was investigated. Comparisons of shear wave velocities from the field and laboratory were favorable for similar moisture and stress conditions. However, results showed that as the degree of saturation increases and suction decreases the shear wave velocity can decrease significantly.
Influence of degree of saturation on the dynamic soil properties of a sandy soil
Authors: Baltodano-Goulding Rafael , Brenes-Garcia Laura
Published: April 2023

It is commonly assumed that the fully-saturated scenario represents the critical shear strength condition for geotechnical structure design; nevertheless, this is not the case when the dynamic shear strength of unsaturated soil is considered, because the water content affects the transfer of seismic waves through the porous medium and into a structure. It is important to better understand this behavior so the soil response during an earthquake could be established to prevent damage or failure of the structure. A series of cyclic triaxial tests with controlled matric suction was conducted to determine the principal dynamic parameters for a sandy soil for different degrees of saturation. Finally, to assess the influence of soil saturation on the dynamic soil properties of a sandy soil, a dynamic lateral load pile design was performed using Reese’s p-y curve method, and the parameter obtained from the laboratory testing were used to backcalculate the seismic coefficients used for structural design. Structural designs of laterally loaded piles considering different soil degrees of saturation demonstrated that the saturated soil condition while subjected to a dynamic condition does not represent the critical load case for seismic analysis.
Coupled stress-suction changes in the Callovo-Oxfordian claystone
Authors: Braun Philipp , Delage Pierre , Ghabezloo Siavash , Talandier Jean
Published: April 2023

Some (saturated) claystones, considered as host rocks for deep radioactive waste disposal, are sensitive to drying and wetting. Wetting may result in swelling and damage during the resaturation of specimens for mechanical testing. Given that, due to evaporation, specimens may have lost some pore water during coring, transport, storage and trimming prior to lab testing, it is required to re-saturate them by reinjecting the evaporated water content, compressing the pore space under constant water content, or by using a combination of both. It is important to characterize the hydromechanical processes involving suction changes under total stress loading in order to adapt preparation methods and minimize sample disturbances. We present a novel experimental setup to test claystone specimens under isotropic compression at constant water content, while measuring suction, and we discuss the data of three specimens testedat different initial suctions and degrees of saturation. Interestingly, the path followed in the (decreased) suction vs (increased) total confining stress diagram was observed to be close to the Gens-Alonso “Neutral Line” (a line inclined of 45° in a suction/mean total stress diagram, illustrating similar effects of changes of both variables). In other words, even in close to saturated conditions, changes in confining stress resulted in comparable changes in suction. The data obtained indicate that applying a total stress of 12.2 MPa during resaturation keeps the material on the compressive side of the Neutral Line, limiting swelling-induced sample disturbance.
Soil-atmosphere interaction: cracking of a compacted soil under the effect of a thermo-hydric stress
Authors: Rosin-Paumier Sandrine , Granados Jaime , Caicedo Bernardo
Published: April 2023

Reusing excavated material in geotechnical engineering reduces the carbon impact of a project. Such materials are usually placed in a compacted state in order to achieve the mechanical and hydric characteristics required to guarantee the safety of the structures. A good geotechnical knowledge of the materials is therefore necessary as well as a good anticipation of their behaviour over time. Indeed, in some situations, as in the case of waste storage, a low hydraulic conductivity is required. The use of crushed rocks rich in clays (argillite), possibly improved by adding bentonite, could be interesting. However, this addition, beneficial in terms of hydraulic conductivity, could be damaging from a mechanical point of view by the development of cracks at the interface atmosphere-compacted soil. For this purpose, samples compacted at the normal Proctor optimum are exposed to a relative humidity of 46% and a temperature of 22.5°C. The thickness, mass and surface condition (cracking) were monitored during the drying process, and measurements were taken in the thickness of the specimen after 29 hours of exposure. The results make it possible to compare the two materials at the same compaction energy. The argillite sample shows a significant shrinkage but no cracks at this scale. On the different hand, with the addition of bentonite, a significant cracking was observed and analysed. These results provide information on the hydromechanical behaviour of unsaturated fine soils at the atmosphere-compacted soil interface.
New challenges in experimental unsaturated soil mechanics. Experimental upscaling of an engineered gas-permeable seal
Authors: Romero Enrique , Alvarado Clara , Lloret Antonio
Published: April 2023

An example of upscaling phenomena with experimental techniques is presented and discussed within an engineered seal concept for a future deep geological repository for low and intermediate radioactive waste mainly produced by the energy/medicine/industry sectors. The seal will undergo a long-term saturation stage and subsequent gas transport through such a barrier. Consequently, gas entrapment and generation processes (dominated by the degradation of organic substances and metals) are expected to occur in the emplacement caverns along the pollutant waste storage. The case concerns a compacted 80/20 (dry mass) sand/bentonite S/B mixture with a complex microstructure that significantly evolves on hydration affecting the gas transport properties. This type of seal limits the gas pressure by increasing its gas transport capacity (gas-permeable seal). The large-scale and demonstration experiment GAST (Nagra’s GTS, Switzerland) focuses on the S/B response to saturation and the gas transport capacity in the later gas invasion phase. A series of laboratory experiments running parallel to the in situ test and bridging different scales (from bentonite inter-sand filling microstructural tests and point tests to dm-scale mock-ups) are discussed within the saturation, gas breakthrough pressure and gas dissipation process of the gas-permeable seal context.
Suction in shales: consequences on triaxial testing
Authors: Delage Pierre
Published: April 2023

Significant interest has been devoted to claystones and shales in the context of geological radioactive waste disposal at great depth. The determination of their mechanical properties is needed for appropriate design of the underground galleries and tunnels. Given their high sensitivity to changes in water content, special care has to be taken so as to provide characteristics as close as possible to the (saturated) insitu ones. Based on the hydromechanical path followed by samples from coring to trimming in the lab, that most often lead to some degree of desaturation resulting from evaporation and drying of the samples, some procedures aimed at minimising the resulting perturbations are described. The considerations presented are based on data obtained on two (swelling) claystones considered in Europe for deep geological disposal, i.e., the Callovo-Oxfordian claystone (France) and the Opalinus Clay (Switzerland).
Model validation using induced tensile stress during cracking process measured with desiccation stress tests
Authors: Sawada Mai , Mimura Mamoru , Yoshikawa Kazuhide
Published: April 2023

Tensile stress is internally induced when soil shrinkage due to desiccation is restricted, and cracks occur when the induced tensile stress reaches tensile strength. Various numerical models have been proposed to predict crack initiation; however, the validity of the computed internal stresses during the cracking process has not been assessed, although the internal stresses directly influence the crack initiation. The aim of this study was to demonstrate the effectiveness of a laboratory-based desiccation stress test, which measures the induced tensile stress until crack initiation. Desiccation stress tests were performed on unsaturated sandy soil with two different water contents. The measured tensile stress until cracking was numerically simulated using a hypo-elastic model based on the skeleton stress considering the suction effects. The computed tensile stress was consistent with the measured values throughout the cracking process in both cases, with different initial water contents. Stress-based validation using the results of the desiccation stress test demonstrated that the proposed constitutive model yields reliable estimations of the internal tensile stress in unsaturated soils until crack initiation.
The impact of soil-vegetation-atmosphere interaction on a landslide initiation under torrential storms: a case study
Authors: Fraccica Alessandro , Romero Enrique , Fallas Josette E.
Published: April 2023

Vegetation has long been used in geotechnical engineering to protect slopes from surface instability phenomena. However, its effects remain difficult to quantify, given the diversity of plants in situ, the variability of their morpho-mechanical characteristics and their impact on soil hydraulic states. For this purpose, the case of a landslide that occurred following torrential rains in Costa Rica was analysed. After the geotechnical characterisation of the soils affected by the movement, the plant species and their main morpho-mechanical characteristics were identified. These characteristics were used to evaluate the changes in the hydromechanical parameters of the soil due to the presence of the roots, and the transpiration rates generated by the plants themselves. In the FE model, a “continuum material” approach was adopted to simulate the vegetated soil numerically, jointly with a failure criterion for partially saturated soils. Using available meteorological data, the evolution of the hydraulic state of the slope in the weeks before and during the storm that caused the landslide was simulated, comparing the cases of vegetated and hypothetically not vegetated slopes. Results validated the observations carried out on the site and confirmed the hydromechanical effects of plants in delaying in time the triggering of the landslide.
Influence of soil suction on runoff during whiplash events
Authors: Bounds Tommy , Muraleetharan Kanthasamy , Miller Gerald
Published: April 2023

The influence of soil suction on rainfall-runoff during whiplash events is explored. A series of 600 finite element simulations were completed using PLAXIS LE Groundwater. A model 2D soil profile was developed in the software to simulate a fat clay soil native to Oklahoma. Rainfall intensity, initial soil suction, and surface slope elevation were treated as log normally distributed random variables. Desiccation cracking was explicitly included in the model as a function of initial soil suction. The depth of the desiccation cracking was determined according to the soil’s tension capacity. the results indicate that rainfall-runoff is greatly influenced by soil suction. For a given rainfall intensity, the portion of the rain that becomes runoff varies according to soil suction; however, this relationship is not strongly correlated. The simulation results exhibit significant variability, which emphasize the complexity of this relationship. The occurrence of desiccation cracking reduced but did not eliminate the potential for rainfall-runoff for desiccation crack depths less than 5 m for the soil in this study.
Experimental Study of Soil Water Characteristic Curve for a Clayey Soil Reinforced with Model Geocell for Freezing-Thawing Cycles
Authors: Dave Bhavita S. , Chavda Jitesh T. , Solanki Chandresh H. , Desai Atul K.
Published: April 2023

The category of geosynthetics includes geocells as a common subclass. As a low-cost, easilyinstalled solution to soil stabilisation problems, geocells are gaining popularity in the field of geotechnical engineering. Assessing and measuring the matric potential of geocell reinforced soil subjected to alternating freezing-thawing cycles depends on understanding the water retention behaviour of the soil. The water retention properties of geocell reinforced soil are influenced by alternate freezing-thawing cycles. For the objective of this study, the thawing soil freezing characteristic curve (SFCC) of a clayey soil with variable numbers of model geocells was determined (0, 1, and 2 number). With the progression of freezingthawing cycles, which dramatically changed the retention behaviour of reinforcing soil, the matric potential was measured using the filter paper method methodology. The thawing SFCC for reinforced soil with model geocell was assessed using the van Genuchten model. For the studied soil with varied numbers of model geocells, the VG model was evaluated for five consecutive freezing-thawing cycles, demonstrating its efficacy in determining the retention behaviour of geocell reinforced soils. The experimental findings showed that the matric potential in SFCC has considerably enhanced due to the presence of model geocell.
An unsaturated soil mechanics approach for performance-based intelligent compaction
Authors: Chen Liuxin , Ghorbani Javad , Tophel Amir , Kodikara Jayantha
Published: April 2023

Intelligent compaction involves using instrumented rollers to provide real-time monitoring of the compacted ground using sensors such as accelerometers and GPS. This technology has the potential to improve productivity and uniformity in construction but its advancement is currently impeded due toinaccurate estimation of the physical ground properties, such as dry density, and the absence of robust quantitative models to predict the effect of compaction on the long-term performance of unsaturated soils under repeated loads. In this study, the compaction of the soil layers and subsequent deformations under repeated traffic loads are simulated by using an advanced computational framework and model for unsaturated soils. By employing an effective stress concept, the presented computational approach allows a unified description of soils at various degrees of saturation. In addition, the model can capture plastic deformations at the initiation of loading and thereby offer accurate predictions of soil behaviour under cyclic loads. Several numerical examples will be provided to demonstrate how the initial states of compacted soils affect the compaction efficiency and the long-term performance of compacted soils.
Temperature- and saturation-dependent behaviour of unsaturated clay beams in bending tests
Authors: Hardenberg Maximilian , Vrettos Christos
Published: April 2023

The paper investigates the deformation behaviour of partially saturated clay beams under flexural stress. Beams were prepared from two clays and then loaded until failure. Three degrees of saturation and two loading rates were examined for each clay. The load, the matric suction at different beam points, and deflection in the middle of the beam were measured during the tests. The loading device ensures an even distribution of stresses on the top surface of the beam, which was confirmed by employing tactile pressure matrix sensors placed between the loading device and the beam. In addition to the tests at room temperature, tests at 55 °C were carried out in a walk-in climate chamber to assess the effects of temperature. The papersummarises the testing procedure and presents selected experimental results.
Water characteristic curve and permeability function of recycled concrete aggregate
Authors: Pernebekova Gulnur , Satyanaga Alfrendo , Abishev Rezat , Moon Sung-Woo , Kim Jong
Published: April 2023

Construction and demolition waste are one of the major waste streams in the world. Aggregates must be used in significant quantities during road construction and maintenance as base and sub-base materials. Government and local businesses are promoting the use of recycled material in old pavement andconstruction material due to the high cost of virgin aggregates. Concrete, road subgrade, and railroad ballast materials can all be made from recycled concrete aggregate (RCA), a type of recycled material. The engineers must properly comprehend the material's qualities, including its unsaturated properties, in order to use RCA in these projects. The goal of this project is to investigate the unsaturated permeability and thewater characteristic curve of RCA. These unsaturated qualities were discovered through sophisticated laboratory experimentation. The study's findings showed that the RCA has the same qualities as gravel or natural aggregate.
Large-Scale Plate Load Tests to Determine the Collapse Potential at Santorini 150 kV GIS Substation Site
Authors: Platis Athanasios , Malliou Konstantina
Published: April 2023

Two large-scale plate load tests were carried out at the foundation level of the Santorini 150 kV GIS Substation, where the subsoil was identified as collapsible. The purpose of these load tests was to establish in-situ, the magnitude of the expected settlements due to the collapse of the subsoil structure after inundation, while applying a bearing pressure equal to the maximum expected according to the structural design. After completion of the tests, which are described in detail, the resulting settlements were found to be acceptable, so no soil improvement measures were required and it was concluded that with the design and execution of these innovative load tests, it was possible to measure under actual field conditions the magnitude of settlement due to collapse of the soil structure. This led to a more economical foundation solution, compared to the one that would have been adopted were only laboratory tests taken into account in the calculation of settlements.
Unsaturated modelling, testing and monitoring towards the rehabilitation of a slope on National Route 3, KwaZulu-Natal, South Africa
Authors: Schulz-Poblete Mario , van der Merwe Frans , Pequenino Fernando
Published: April 2023

The stability of over-steep road embankments often worsens with time. In many cases the slope deterioration can be ascribed to continual downslope creep of a surficial layer of soil that has been affected by infiltration of rainfall. Such infiltration reduces the suction in the surficial layer interacting with the environment. With every season the surficial layer moves further downslope, often resulting in cracks in theslow lane and placing structures constructed at the crest of fill slopes in potential jeopardy. A slope on the National Route 3 (N3), in the South African Province of KwaZulu-Natal, constructed at roughly 40° from the horizontal showed signs of distress in the slow lane many years after construction. The rehabilitation of this slope required stabilisation design using unsaturated soil testing, modelling, and in-situ suction measurement. The slope was stabilised using soil nails, a high-tensile steel mesh, and a suction measurement system was installed. An overview of the emergency works design, subsequent investigation, and monitoring is provided in this paper. It was found that the suction profile determined by transient finiteelement analysis matched well with the measured suction profile and provided a good basis for the emergency design works prior to full investigation.
Transpiration in the water-limited regime: soil-plant-atmosphere interactions
Authors: Tarantino Alessandro , Roberts-Self Eve
Published: April 2023

The use of vegetation to improve stability of natural and engineered slopes is an engineering Nature Based Solution. One effect of vegetation is to reinforce slopes ‘hydrologically’, i.e., by generatingsuction by the removal of soil water via transpiration. In turn, the depletion of soil water content reduces the hydraulic conductivity of the shallow layers of the soil, and this hinders rainwater infiltration during the wet period, possibly preserving suction in the deeper layers susceptible to failure. To improve upon thisstabilising technique, it is key to develop transpiration models that account for the hydraulic characteristics of the soil and plant (below- and above-ground). In this way, modelling can guide the choice of the plant functional traits. This paper first discusses the conceptual and experimental limitations of common empirical evapotranspiration reduction functions (e.g. Feddes function) and then revisits the physically-based ‘bottlenecks’ generating the decline in evapotranspiration in the water-limited regime within the framework of the Soil-Plant-Atmosphere Continuum.
Effect of Soil-Water Characteristic Curve on the Stability of Unsupported Vertical Trenches in Unsaturated Soils
Authors: Oh Won-Taek , Bajestani Mahsa
Published: April 2023

In geotechnical engineering practice, unsupported vertical trenches are typically excavated in unsaturated soils. In this case, the variation of shear strength and hydraulic conductivity with respect to soil suction is key information to analyze the stability of an unsupported vertical trench. Most shear strength and hydraulic conductivity models use the soil-water characteristic curve (SWCC) as a main tool. Various models are available to determine SWCC, shear strength, and hydraulic conductivity for unsaturated soils. Scholars or practitioners use one the existing models in numerical analyses to estimate the stability of unsupported vertical trench considering rainfall events. However, limited studies have been undertaken to investigate the effect of SWCC and hydraulic conductivity functions on the stability of unsupported vertical trenches in unsaturated soils. In the present study, numerical stability analyses are carried out by using different SWCCs and hydraulic conductivity functions to investigate their influence on the estimated safe height and stand-up time of unsupported vertical trenches. The same shear strength model was used for entire numerical analyses.
A multidisciplinary study on the spatial variability of the local stratigraphic conditions in partially saturated slopes for flow-like landslide prediction
Authors: Pirone Marianna , Di Maio Rosa , Forte Giovanni , De Paola Claudio , Guglielmi Simona , Salone Rosanna , Santo Antonio , Urciuoli Gianfranco
Published: April 2023

Flow-like landslides, which occur mainly in shallow granular deposits resting on steep bedrock, represent a major natural hazard worldwide. The pore water pressure distribution and the soil water content directly affect the soil shear strength, thus controlling the triggering of these landslides. Criticalgeomorphological and topographical settings, together with peculiar stratigraphic and hydrogeological features, are commonly recognized as predisposing factors for flow-like landslides occurrence. Hence, investigating the spatial and temporal variability of hydraulic slope conditions is a fundamental activity that consists of identifying local geological factors and seasonal monitoring of the subsurface water regime. The present work proposes an integrated geological, geophysical and geotechnical approach to identify the spatial variability of the local stratigraphic setting and hydrogeological conditions in a partially saturated slope, in order to set up a procedure able to provide a prediction of the flow-like landslides occurrence atslope scale. The multidisciplinary study has been applied to a test site on Mt. Faito, in the Lattari Mts. (Southern Italy), where extensive geophysical, geological and geotechnical soil characterization and in situmonitoring data collected over two years are available.