bluuebunny/crossref_metadata_2025 huggingface dataset:
Resistance exercise training for anxiety and worry symptoms among young adults: a randomized controlled trial
Authors: Gordon Brett R. , McDowell Cillian P. , Lyons Mark , Herring Matthew P.
Published: October 2020

This trial quantified the effects of ecologically-valid resistance exercise training (RET) on anxiety and worry symptoms among young adults. Young adults not meeting criteria for subclinical, or analogue Generalized Anxiety Disorder (AGAD) were randomized to an eight-week RET intervention, or eight-week wait-list. AGAD status was determined using validated cut-scores for both the Psychiatric Diagnostic Screening Questionnaire-Generalized Anxiety Disorder subscale (≥ 6) and Penn State Worry Questionnaire (≥ 45). The primary outcome was anxiety symptoms measured with the Trait Anxiety subscale of the State-Trait Anxiety Inventory. The RET was designed according to World Health Organization and American College of Sports Medicine guidelines. RM-ANCOVA examined differences between RET and wait-list over time. Significant interactions were decomposed with simple effects analysis. Hedges’ d effect sizes quantified magnitude of differences in change between RET and wait-list. Twenty-eight participants (64% female) fully engaged in the trial (mean age: 26.0 ± 6.2y, RET: n = 14; Wait-list: n = 14). A significant group X time interaction was found for anxiety symptoms (F(3,66) = 3.60, p ≤ 0.019; d = 0.85, 95%CI: 0.06 to 1.63). RET significantly reduced anxiety symptoms from baseline to post-intervention (mean difference =  − 7.89, p ≤ 0.001). No significant interaction was found for worry (F(3,69) = 0.79, p ≥ 0.50; d =  − 0.22, 95%CI: − 0.96 to 0.53). Ecologically-valid RET significantly improves anxiety symptoms among young adults.

Trial Registration: Clinicaltrials.gov Identifier: NCT04116944, 07/10/2019.
The influence of climate variability on demographic rates of avian Afro-palearctic migrants
Authors: Telenský Tomáš , Klvaňa Petr , Jelínek Miroslav , Cepák Jaroslav , Reif Jiří
Published: October 2020

Climate is an important driver of changes in animal population size, but its effect on the underlying demographic rates remains insufficiently understood. This is particularly true for avian long-distance migrants which are exposed to different climatic factors at different phases of their annual cycle. To fill this knowledge gap, we used data collected by a national-wide bird ringing scheme for eight migratory species wintering in sub-Saharan Africa and investigated the impact of climate variability on their breeding productivity and adult survival. While temperature at the breeding grounds could relate to the breeding productivity either positively (higher food availability in warmer springs) or negatively (food scarcity in warmer springs due to trophic mismatch), water availability at the non-breeding should limit the adult survival and the breeding productivity. Consistent with the prediction of the trophic mismatch hypothesis, we found that warmer springs at the breeding grounds were linked with lower breeding productivity, explaining 29% of temporal variance across all species. Higher water availability at the sub-Saharan non-breeding grounds was related to higher adult survival (18% temporal variance explained) but did not carry-over to breeding productivity. Our results show that climate variability at both breeding and non-breeding grounds shapes different demographic rates of long-distance migrants.
Biosynthesis and characterization of silver nanoparticles using Ochradenus arabicus and their physiological effect on Maerua oblongifolia raised in vitro
Authors: Shaikhaldein Hassan O. , Al-Qurainy Fahad , Nadeem Mohammad , Khan Salim , Tarroum Mohamed , Salih Abdalrhaman M.
Published: October 2020

Silver nanoparticles (AgNPs) are presently the most commonly generated engineered nanomaterials and are found in a wide range of agro-commercial products. The present study was designed to synthesize AgNPs biologically using Ochradenus arabicus leaves and investigate their effect on the morphophysiological properties of Maerua oblongifolia raised in vitro. Physicochemical methods (ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy were performed for characterization and for obtaining microphotographs of the AgNPs. Shoots of M. oblongifolia (2–3 cm) grown in Murashige and Skoog medium supplemented with different concentrations of AgNPs (0, 10, 20, 30, 40, or 50 mg L−1) were used. Following 6 weeks of in vitro shoot regeneration, the shoot number, shoot length, leaf number, fresh weight, dry weight, chlorophyll content, total protein, proline level, and antioxidant enzyme activities of the plants were quantified. We found that 20 mg L−1 AgNPs increased the shoot number, shoot length, fresh weight, dry weight, and chlorophyll content of the plants. The maximum total protein was recorded in plants that were administered the lowest dose of AgNPs (10 mg L−1), while high concentrations of AgNPs (40 and 50 mg L−1) increased the levels of proline and the enzymes superoxide dismutase and catalase. Our results indicate that green-synthesized AgNPs may be of agricultural and medicinal interest owing to their effects on plants in vitro.
Risk factors for type 1 diabetes, including environmental, behavioural and gut microbial factors: a case–control study
Authors: Traversi Deborah , Rabbone Ivana , Scaioli Giacomo , Vallini Camilla , Carletto Giulia , Racca Irene , Ala Ugo , Durazzo Marilena , Collo Alessandro , Ferro Arianna , Carrera Deborah , Savastio Silvia , Cadario Francesco , Siliquini Roberta , Cerutti Franco
Published: October 2020

Type 1 diabetes (T1D) is a common autoimmune disease that is characterized by insufficient insulin production. The onset of T1D is the result of gene-environment interactions. Sociodemographic and behavioural factors may contribute to T1D, and the gut microbiota is proposed to be a driving factor of T1D. An integrated preventive strategy for T1D is not available at present. This case–control study attempted to estimate the exposure linked to T1D to identify significant risk factors for healthy children. Forty children with T1D and 56 healthy controls were included in this study. Anthropometric, socio-economic, nutritional, behavioural, and clinical data were collected. Faecal bacteria were investigated by molecular methods. The findings showed, in multivariable model, that the risk factors for T1D include higher Firmicutes levels (OR 7.30; IC 2.26–23.54) and higher carbohydrate intake (OR 1.03; IC 1.01–1.05), whereas having a greater amount of Bifidobacterium in the gut (OR 0.13; IC 0.05 – 0.34) was a protective factor for T1D. These findings may facilitate the development of preventive strategies for T1D, such as performing genetic screening, characterizing the gut microbiota, and managing nutritional and social factors.
Ensemble learning predicts multiple sclerosis disease course in the SUMMIT study
Authors: Zhao Yijun , Wang Tong , Bove Riley , Cree Bruce , Henry Roland , Lokhande Hrishikesh , Polgar-Turcsanyi Mariann , Anderson Mark , Bakshi Rohit , Weiner Howard L. , Chitnis Tanuja ,   SUMMIT Investigators
Published: October 2020

The rate of disability accumulation varies across multiple sclerosis (MS) patients. Machine learning techniques may offer more powerful means to predict disease course in MS patients. In our study, 724 patients from the Comprehensive Longitudinal Investigation in MS at Brigham and Women’s Hospital (CLIMB study) and 400 patients from the EPIC dataset, University of California, San Francisco, were included in the analysis. The primary outcome was an increase in Expanded Disability Status Scale (EDSS) ≥ 1.5 (worsening) or not (non-worsening) at up to 5 years after the baseline visit. Classification models were built using the CLIMB dataset with patients’ clinical and MRI longitudinal observations in first 2 years, and further validated using the EPIC dataset. We compared the performance of three popular machine learning algorithms (SVM, Logistic Regression, and Random Forest) and three ensemble learning approaches (XGBoost, LightGBM, and a Meta-learner L). A “threshold” was established to trade-off the performance between the two classes. Predictive features were identified and compared among different models. Machine learning models achieved 0.79 and 0.83 AUC scores for the CLIMB and EPIC datasets, respectively, shortly after disease onset. Ensemble learning methods were more effective and robust compared to standalone algorithms. Two ensemble models, XGBoost and LightGBM were superior to the other four models evaluated in our study. Of variables evaluated, EDSS, Pyramidal Function, and Ambulatory Index were the top common predictors in forecasting the MS disease course. Machine learning techniques, in particular ensemble methods offer increased accuracy for the prediction of MS disease course.
Mineral-mediated carbohydrate synthesis by mechanical forces in a primordial geochemical setting
Authors: Haas Maren , Lamour Saskia , Christ Sarah Babette , Trapp Oliver
Published: October 2020

The formation of carbohydrates represents an essential step to provide building blocks and a source of chemical energy in several models for the emergence of life. Formaldehyde, glycolaldehyde and a basic catalyst are the initial components forming a variety of sugar molecules in the cascade-type multi-step formose reaction. While numerous side reactions and even deterioration can be observed in aqueous media, selective prebiotic sugar formation is feasible in solid-state, mechanochemical reactions and might have occurred in early geochemistry. However, the precise role of different basic catalysts and the influence of the atmospheric conditions in the solid-state formose reaction remain unknown. Here we show, that in a primordial scenario the mechanochemical formose reaction is capable to form monosaccharides with a broad variety of mineral classes as catalysts with only minute amounts of side products such as lactic acid or methanol, independent of the atmospheric conditions. The results give insight into recent findings of formose sugars on meteorites and offer a water-free and robust pathway for monosaccharides independent of the external conditions both for the early Earth or an extra-terrestrial setting.
Enhanced H2 production from dehydrogenation of sodium borohydride over the ternary Co0.97Pt0.03/CeOx nanocomposite grown on CGO catalytic support
Authors: Kotkondawar Abhay Vijay , Rayalu Sadhana
Published: October 2020

Synergistic interactions among Co/Co3O4, CeOx and Pt counterparts, and the co-operative effect of CGO play a significant role in the complete dehydrogenation of sodium borohydride.
Porous manganese–cobalt oxide microspheres with tunable oxidase mimicking activity for sulfide ion colorimetric detection
Authors: Wang Xue , Feng Shiya , He Daiping , Jiang Ping
Published: October 2020

Porous MnxCo1−xO microspheres derived from Mn–Co PBA with tunable oxidase-like activity and high efficiency in S2− colorimetric detection.
Copper-catalyzed oxidative decarboxylative alkylation of cinnamic acids with 4-alkyl-1,4-dihydropyridines
Authors: Zhang Dong , Tang Zi-Liang , Ouyang Xuan-Hui , Song Ren-Jie , Li Jin-Heng
Published: October 2020

An oxidative decarboxylation of cinnamic acids with 4-alkyl-1,4-dihydropyridines to construct internal alkenes under copper catalyst and dicumyl peroxide (DCP) with excellent stereoselectivity.
Multi-dimensional architecture of Ag/α-Ag2WO4 crystals: insights into microstructural, morphological, and photoluminescence properties
Authors: Cruz Lílian , Teixeira Mayara M. , Teodoro Vinícius , Jacomaci Natalia , Laier Letícia O. , Assis Marcelo , Macedo Nadia G. , Tello Ana C. M. , da Silva Luís F. , Marques Gilmar E. , Zaghete Maria A. , Teodoro Márcio D. , Longo Elson
Published: October 2020

Varying the concentration of ethylenediamine resulted in hollow or solid Ag/α-Ag2WO4 microflowers that emit light in the red region or in the blue region, respectively.
Defect structure and vibrational states in Eu-doped cubic gadolinium oxide
Authors: Kislov Alexey N. , Zatsepin Anatoly F.
Published: October 2020

We consider an effect of trivalent Eu impurities occupying two different crystallographic positions in cubic gadolinium oxide on its lattice structure and phonon spectrum.
Promotional effects of modified TiO2- and carbon-supported V2O5- and MnOx-based catalysts for the selective catalytic reduction of NOx: a review
Authors: Raja S. , Alphin M. S. , Sivachandiran L.
Published: October 2020

This review presents the promotional effects of transition metal modification over TiO2- and carbon-supported V2O5- and MnOx-based SCR catalysts.
Loading of individual Se-doped Fe2O3-decorated Ni/NiO particles on carbon cloth: facile synthesis and efficient electrocatalysis for the oxygen evolution reaction
Authors: Shah Sayyar Ali , Zhu Guoxing , Yuan Aihua , Ullah Nabi , Shen Xiaoping , Khan Habib , Xu Keqiang , Wang Xuyu , Yan Xiufen
Published: October 2020

Se-Fe2O3@Ni/NiO/CC is synthesizedviaa one-step thermal method and exhibits outstanding OER performances due to the synergetic effects between the Se-Fe2O3and Se–Ni/NiO particles.
All-graphene-based open fluidics for pumpless, small-scale fluid transport via laser-controlled wettability patterning
Authors: Hall Lucas S. , Hwang Dohgyu , Chen Bolin , Van Belle Bryan , Johnson Zachary T. , Hondred John A. , Gomes Carmen L. , Bartlett Michael D. , Claussen Jonathan C.
Published: October 2020

We present an all-graphene based open microfluidic manufacturing technique by manipulating the surface wettability of spin-coated graphene ink films via laser-controlled patterning. The approach is rapid, flexible, and opens diverse applications in fluid transport.
NiFe2O4/poly(ethylene glycol)/lipid–polymer hybrid nanoparticles for anti-cancer drug delivery
Authors: Joshy K. S. , Augustine Robin , Mayeen Anshida , Alex Susan M. , Hasan Anwarul , Thomas Sabu , Chi Hong
Published: October 2020

The present study reports the fabrication of hybrid nanoparticles consisting of nickel ferrite (NFO) for anti cancer drug delivery.
Amino-functionalized copper-based metal–organic frameworks for highly selective and sensitive detection of hypochlorite
Authors: Huo Panpan , Li Zhijian , Fan Congbin , Pu Shouzhi
Published: October 2020

In this work, we have developed amino-functionalized copper-based metal–organic frameworks (NH2-Cu-MOFs) for the detection of hypochlorite (ClO−).
The C–H functionalization of organic cations: an interesting and fresh journey
Authors: Yu Yu , Lv Hongxu , Li Shiqing
Published: October 2020

This review summarizes the substantial progress that has been made relating to the C–H functionalization of organic cations, and it covers transition-metal-enabled C–H alkylation, arylation, and photo-induced C–H functionalization.
The same oxygenation-state introduction of hypervalent sulfur under transition-metal-free conditions
Authors: Zeng Daming , Wang Ming , Deng Wei-Ping , Jiang Xuefeng
Published: October 2020

This review discusses the application of the same oxygenation-state introduction of hypervalent sulfur strategy under transition-metal-free conditions.
Reagentless and sensitive determination of carcinoembryonic antigen based on a stable Prussian blue modified electrode
Authors: Lin Jing , Li Kunyin , Wang Meifang , Chen Xiaohong , Liu Jiyang , Tang Hongliang
Published: October 2020

A label-free electrochemical sensor is easily fabricated based on stable and surface-confined Prussian blue for reagentless and sensitive detection of carcinoembryonic antigen.
Probing the supramolecular featuresviaπ–π interaction of a di-iminopyrene-di-benzo-18-crown-6-ether compound: experimental and theoretical study
Authors: Coroaba Adina , Isac Dragos-Lucian , Al-Matarneh Cristina , Vasiliu Tudor , Ibanescu Sorin-Alexandru , Zonda Radu , Ardeleanu Rodinel , Neamtu Andrei , Timpu Daniel , Nicolescu Alina , Mocci Francesca , Maier Stelian S. , Laaksonen Aatto , Abadie Marc Jean Médard , Pinteala Mariana
Published: October 2020

Herein, we report the formation of a potential supramolecular arrangement mediated by inter- and intra-molecular interactions between di-iminopyrene-dibenzo-18-crown-6-ether molecules.
Correction: DFT/TDDFT insights into the chemistry, biochemistry and photophysics of copper coordination compounds
Authors: Tsipis Athanassios C.
Published: October 2020

Correction for ‘DFT/TDDFT insights into the chemistry, biochemistry and photophysics of copper coordination compounds’ by Athanassios C. Tsipis, RSC Adv., 2014, 4, 32504–32529, DOI: 10.1039/C4RA04921G.
Not just a fluidifying effect: omega-3 phospholipids induce formation of non-lamellar structures in biomembranes
Authors: de Santis Augusta , Vitiello Giuseppe , Appavou Marie-Sousai , Scoppola Ernesto , Fragneto Giovanna , Barnsley Lester C. , Clifton Luke A. , Ottaviani Maria Francesca , Paduano Luigi , Russo Krauss Irene , D’Errico Gerardino
Published: October 2020

Beyond a threshold concentration, omega-3 phospholipid 22:6-22:6PC hampers the formation of a typical lamellar phase of lipid membranes forming small spherical aggregates.
Aggregation of a double hydrophilic block glycopolymer: the effect of block polymer ratio
Authors: Oh Takahiro , Hoshino Yu , Miura Yoshiko
Published: October 2020

Double hydrophilic block glycopolymers (DHBGs) composed of glycopolymers and polyethylene glycol (PEG) aggregate in aqueous solution.
MiR-106b-5p regulates the migration and invasion of colorectal cancer cells by targeting FAT4
Authors: Pan Min , Chen Qiuqiu , Lu Yusong , Wei Feifei , Chen Chunqiao , Tang Guiyan , Huang Hui
Published: October 2020

MicroRNA-106b-5p (miR-106b-5p) is involved in the development of many cancers including colorectal cancer (CRC), and FAT4 is correlated with regulation of growth and apoptosis of cancer cells. The present study aimed to investigate the relation between FAT4 and miR-106b-5p and the underlying mechanism of the two on the development of CRC. Quantitative real-time PCR (qRT-PCR) assay and Western blot (WB) analysis were performed to detect the expressions of messenger RNAs (mRNAs), microRNAs (miRNAs) and proteins. The viability of CRC cells was detected by cell counting kit-8 (CCK-8). Scratch test and transwell assay were performed to measure the migration and invasion of CRC cell. Tumor angiogenesis was simulated by in vitro angiogenesis experiment. Dual-luciferase reporter assay was performed to verify the targeting relation between miR-106b-5p and FAT4. The study found that the expression of FAT4 was down-regulated and that of miR-106b-5p was up-regulated in CRC tissues. Overexpression of FAT4 resulted in decreased proliferation, migration, invasion and angiogenesis of CRC cells, whereas silencing of FAT4 led to the opposite results. In rescue experiment, miR-106b-5p partially reversed the function of FAT4 in CRC cells, thus playing a carcinogenic role by targeting FAT4 in the CRC cells.
Joint coding bit‐rate and activity rate optimisation in wireless visual sensor networks
Authors: Kafafy Mai , Fahmy Yasmine
Published: October 2020

Optimising the coding bit‐rates and activity rates of sensor nodes is essential for the functionality and survival of wireless sensor networks as these rates not only affect the amount of information collected by the network, but also affect its power consumption. This study proposes a framework for joint coding bit‐rates and activity rates optimisation (CARO) of sensor nodes in wireless visual sensor networks under limited energy constraints. The framework uses the concept of accumulative visual information (AVI) as a measure of the amount of visual information collected from a sensor node. The authors propose two optimisation algorithms for the following two cases: (I) networks with predetermined operation time, where algorithm CARO I maximises the AVI of the network over its predetermined operation time. (II) Best effort networks, where algorithm CARO II maximises the network operation time under constraints on the collected visual information. Simulations show that optimising the rates using CARO maximises the AVI of the network and extends its operation time compared to the straightforward solution when all nodes have equal activity rates. This is because the authors' framework takes into consideration that different nodes in different locations may operate under different conditions and collect information of different significance.
Extended Kalman filter based estimations for improving speed‐sensored control performance of induction motors
Authors: Yildiz Recep , Barut Murat , Demir Ridvan
Published: October 2020

In this study, an extended Kalman filter (EKF)‐based estimation algorithm is presented to improve the speed‐sensored control performance of induction motors (IMs). The proposed EKF‐based estimation algorithm is to simultaneously estimate the stator stationary axis components of stator currents and rotor fluxes, rotor angular speed, load torque including viscous friction term, rotor resistance and magnetising inductance in a single EKF algorithm without requiring any switching operation or a hybrid structure. In order to improve the speed‐sensored control performance, the measurement/output matrix of IM model is extended by the measured rotor speed in addition to stationary axis components of the measured stator currents. Therefore, the proposed EKF algorithm uses the speed and stator current errors between the measured and priori estimation values in order to calculate the posterior estimation ones. For performance evaluation, the eighth order (proposed) EKF algorithm is tested by simulations and real‐time experiments under challenging scenarios and compared with the developed sixth order EKF in real time. The obtained real‐time results also show that the eighth order (proposed) EKF algorithm provides additional and improved estimations with the increased but feasible execution time in terms of the sixth order EKF designed in this paper.
Behavior of unsaturated pelitic soil in a railway context
Authors: Yoka Khail Bilal , Morvan Mathilde , Breul Pierre
Published: October 2020

As part of the rehabilitation work on the Gabonese railway line, the Trans-Gabon Railway, it was necessary to analyse the behaviour of the materials constituting the subgrade soil. These soils are pelitic soils whose behaviour under unsaturated conditions and cyclic loading has not been studied before and which present differential settlements and lack of bearing capacity. In this article, we focus on the characterization of the subgrade soil. The objective of this work is first to determine the in-situ characteristics of the pelitic soil and be able to link these characteristics with the behaviour studied in laboratory. For that purpose, we propose an in-situ investigation based on the use of light dynamic penetrometric tests in order to assess the variability of the subgrade layer and a drying-wetting test to assess the influence of hydric stress on the drainage path of the studied soil. We present the results of in-situ tests performed on a study area. We also present the results of the tests to determine the soil water characteristic curves (SWCC) and the curves describing the volumetric behaviour of this soil when exposed to drying.
Simulating the drying behavior of rammed earth columns
Authors: Chauhan Parul , Moussa Elio , Prime Noémie , Wheeler Simon , Plé Olivier
Published: October 2020

Rammed earth construction provides an efficient alternative construction material to limit energy consumption and CO2 emission. It possesses various characteristics of a sustainable material, but its mechanical capacity is sensitive to humidity variations. It is, therefore, important to better understand water transport within rammed earth when subjected to varying ambient conditions. In this context, the present work aims to analyze the hydraulic behavior of a reduced piece of rammed earth wall consisting of a column of size 14cm x 14cm x 30cm subjected to drying from the initial compaction water content in an indoor environment. The columns had transient non-uniform relative humidity, which was measured in-situ. Thermo-hydraulic coupled numerical modeling was developed using realistic atmospheric boundary conditions. The material and hydric parameters were chosen from an experimental study previously performed at the material scale. A parametric study was performed in order to evaluate the sensitivity of the modeling to both material parameters and boundary conditions. The results of the numerical simulations were highly sensitive to parameter values used for the water retention curve and the surface mass transfer coefficient, with a satisfactory matching of experimental results only achieved after adjusting initial estimates of relevant parameter values.
Field monitoring of soil-moisture to understand the hydrological response of a road-cut slope
Authors: Pradhan Samprada , Toll David G. , Rosser Nick J. , Brain Matthew J.
Published: October 2020

Rainfall and slope-cutting for road construction are two key landslide causative factors in Nepal, but how they interact to cause failures is poorly understood. To improve understanding of the effects of cut slopes during rainfall, geotechnical investigations and field monitoring were conducted in a mountainous district, Sindhupalchowk, located in central Nepal. This paper presents the results of the field-investigations and the measurements of volumetric water content obtained from the sensors installed in the study-site. Field-based evidence suggests that the slope that was cut for road construction during the dry period remained stable due to the presence of soil suction, which imparted additional strength to the soil. At the start of the monsoon, infiltration of rainwater caused saturation of the soil at shallow depth, consequently causing loss of suction and reduction of the soil strength. The presence of the road-cut in the hillslope resulting in steeper slopes then promoted the failure. These observations suggest that the presence of road-cuts in the hillslopes can cause landslides even during non-exceptional rainfall events.
An unfrozen water retention curve for capturing soil density and specific surface effects
Authors: Zhang Jiwen , Mu Qingyi , Liao Hongjian , Cao Jie
Published: October 2020

Unfrozen water retention curve (UWRC) defines the relationship between temperature and unfrozen water content in frozen soils. Although many models have been proposed for the UWRC, these existing models cannot predict UWRC well over a wide temperatures range. In this study, a new UWRC model is proposed with explicit considerations of both capillarity and adsorption. In this model, capillarity is considered dominating when the freezing of soil pore water at higher temperatures (above -2oC), whereas the effects of adsorption pronounce at temperatures below -2oC. Moreover, effects of void ratio on the freezing of capillary water are incorporated. The proposed model was applied to predict UWRCs of silt and clay at different initial void ratios over a wide temperature range (from -50 to 0oC). Predicted results by this new model are compared with predictions by three well-known existing models. The new model can capture the density effects on UWRC. Moreover, the new model can predict better UWRC over a wide temperature range since it explicitly considers both effects of capillarity and adsorption.
Expansive Clay Cracking Behavior through Digital Image Correlation
Authors: Araujo Arthur Gomes Dantas de , Belfort Nayara Torres , Barbosa Felipe Araujo Silva , Silva Thalita Cristiana Rodrigues , Ferreira Silvio Romero de Melo , Guimarães Leonardo José do Nascimento , Bezerra Izabela Medeiros de Lima
Published: October 2020

Expansive soils may present cracks arising from the drying process and their evolution can cause irreparable damages to engineering projects. Investigating this phenomenon is vital to understanding its geomechanics. The objective of this article is to present numerical modelling of the formation and propagation of cracks in expansive soil. A desiccation experiment was therefore carried out using an expansive silty clay from Paulista, in northeastern Brazil. The drying process was monitored by measuring the temperature and relative humidity of the air, as well as by capturing images with a camera. The digital images were correlated using the Ncorr numerical tool in MATLAB. As a result, this study made it possible to conclude that the soil cracking dynamics presented a non-orthogonal pattern during the dryness test, while the image treatment made it possible to observe the tendency of cracks to appear and propagate on the soil surface, allowing for the detection of crack growth and propagation trends.
Image-based measurements of degree of saturation
Authors: Parera Ferran , Pinyol Núria , Alonso Eduardo
Published: October 2020

A method based on SWIR images is proposed for measuring the degree of saturation in soils. This method is especially suitable for use in experiments conducted in the facilities of a common geotechnical laboratory. The method uses images on the short-wave infrared (SWIR) (wavelength: 1400– 1550 nm), which is highly absorbed by water compared with the other bands of the light spectrum (visible and near-infrared). The paper presents the basis of the method and the procedure to measure the degree of saturation in a massive and non-invasive way. A relation curve to transform the pixel intensity values to the degree of saturation is provided for samples of a beach sand. The non-linearity of this curve is discussed and related to the optical path length.
Water retention behaviour of compacted and reconstituted scaly clays
Authors: Rosone Marco , Ferrari Alessio
Published: October 2020

The paper presents the results of an experimental research devoted to investigate the response to suction variations of a scaly clay in compacted and reconstituted conditions. Different experimental techniques (axis translation, vapour equilibrium, dew point psychrometer suction measurements) were combined in order to explore the water retention properties in a wide suction range (0 ÷ 110 MPa). Experimental results allowed to define the water retention domains for a constant reference void ratio, highlighting the significant role of the microstructure on the response of the investigated clays. In particular, the collected results showed that in the low-medium suction range, the peculiar microstructural features give to the reconstituted clay a better retention capability than the compacted clay. However, the increasing suction induces a significative volumetric shrinkage on the saturated reconstituted clay, especially when the latter is initially normally consolidated. On the other hand, quite similar retention properties were recognized in the high suction range.
Impacts of Unsaturated Conditions on The Ultimate Axial Capacity of Energy Piles
Authors: Behbehani Fatemah , McCartney John S.
Published: October 2020

This study uses concepts from unsaturated soil mechanics to explain changes in axial capacity observed in geotechnical centrifuge experiments on semi-floating energy piles in unsaturated silt heated monotonically to different temperatures. Thermally-induced drying of the unsaturated silt surrounding energy piles was observed during heating using temperature-corrected dielectric sensor readings. An effective stress-based equation for estimating the ultimate capacity was calibrated using the load-settlement curves for a pile at room-temperature, which was then used to estimate the ultimate capacities of energy piles under elevated temperatures using measured changes in degree of saturation near the energy pile. The predicted capacity matched well with the capacity from the experimental load-settlement curves, confirming the relevance of the effective stress principle in unsaturated soils in nonisothermal conditions and the importance of considering coupled heat transfer and water flow in unsaturated soils surrounding energy piles.
Gas transport in granular compacted bentonite: coupled hydro-mechanical interactions and microstructural features
Authors: Gonzalez-Blanco Laura , Romero Enrique , Marschall Paul
Published: October 2020

The initial conditions (dry density and saturation state), the stress state and its history, and the deformation undergone during gas migration, affect the gas transport processes in granular compacted bentonite. Additionally, the sample microstructure set on compaction has a significant influence since gas tends to flow through preferential pathways. This experimental study intends to shed light on the gas transport and their coupled hydro-mechanical interactions with particular emphasis in the changes of the pore and pathway network. Controlled volume-rate gas injection followed by shut-off and dissipation stages have been performed under oedometer conditions. The microstructure of the samples has been characterised with three different techniques before and after the gas injection tests: Mercury Intrusion Porosimetry (MIP), Field-Emission Scanning Electron Microscopy (FESEM) and X-ray Micro-Computed Tomography (μ-CT). The results show a coupling of the deformational behaviour during the gas flow, revealing an expansion of the samples upon the development of gas pathways, which have been detected with the microstructural techniques. The opening of these pressure-dependent and connected pathways plays a major role in gas migration.
Numerically reproduced HE-E experiment of Mont Terri project by Thermo-Hydro-Mechanical coupled model
Authors: Sato Shin , Yamamoto Shuichi , Torisu Seda , Fukaya Masaaki , Tawara Yasuhiro , Tanaka Kei , Florian Kober
Published: October 2020

In this study, numerical simulations of HE-E experiment in Mont Terri rock laboratory were performed with Thermo–Hydro–Mechanical (THM) coupled processes. The aim of this study is to validate modelling, understand THM coupled behaviour and verify applicability of material parameters obtained by a column test to the full-scale model. The results of THM and TH coupled analysis are compared, and the influence of fluid and thermal terms/factors on mechanical behaviour is discussed. The analysis code used for THM and TH coupled analysis was CODE_BRIGHT. An axisymmetric analytical model, which allowed modelling of two heaters, was used for the THM and TH coupled model, and their results were compared. As a result, a better reproducibility of relative humidity in the Engineered Barrier System (EBS) and pore water pressure of the bedrock was achieved by performing mechanical coupling. Furthermore, experimental conditions were simulated more realistically, since two heathers and different backfill materials were also modelled in the analysis.
Seasonal and annual variations in the strength of the atmospheric electric field in the 24th cycle of solar activity measured in Yakutsk
Authors: Toropov Anatoliy , Kozlov Vladimir , Karimov Rustam
Published: October 2020

The paper presents the results of measuring the strength of the atmospheric electric field in fair weather conditions in the 24th cycle of solar activity from 2009 to 2019 according to observations in Yakutsk (North-east of Siberia). Intensity of the atmospheric electric field measurements by an electric field-mill sensor, mounted on the roof of the main building of the SchICRA SB RAS (N 62 ° 1 ‘, E129 ° 43’) in Yakutsk. The field-mill sensor has a measurement range of the atmospheric electric field strength +/- 50 kV/m with an accuracy of +/- 1 V/m. The data acquisition system based on a personal computer and an analog-to-digital converter (ADC) E 14-440 L-Card. Data is written to the hard disc drive of the data acquisition system with a one second resolution data. Based on the analysis of data on the atmospheric electric field from 2009 to 2019 it was found that the seasonal variation of the monthly mean values of the field strength has maxima in the spring and autumn months and minima in the summer and winter months. Annual variations of the field strength in fair weather conditions over the observation period have a general trend towards a decrease in the field strength.
Analysis of the seismic process of the Bishkek geodynamic test site (Northern Tien Shan)
Authors: Sychev Vladimir , Sycheva Naylya
Published: October 2020

Various characteristics of seismic process on the territory of Bishkek geodynamic proving ground are considered. Seismicity analysis is performed on the basis of earthquake catalogue, according to KNET network data. The catalog includes more than 10,000 seismic events that occurred from 1994 to 2019. To describe the energy distribution function of earthquakes, the Gutenberg - Richter law was used, as well as the position of nonequilibrium thermodynamics with the use of Tsallis statistics, which generalizes classical thermodynamics to the case of nonextensive systems. It is shown that the flow of earthquakes on the territory of the Bishkek geodynamic proving ground is a system with memory and long-range spatial correlations, and the study region itself is characterized as seismically active. The following seismic process characteristics are distributed in space and in time:KSRseismogenic fracture parameter, seismotectonic deformation intensity, seismic activity, Tsallis parameterqand constantsa, as well as a parameter characterizing the slope of the repeatability graph (b-value).
Ionosphere modification and topology of ionospheric magnetically-oriented irregularities
Authors: Sivokon’ Vladimir
Published: October 2020

One of the perspective directions of active impact on the ionosphere is the for-mation of electron concentration irregularities. Such irregularities can be used to increase the efficiency of radar systems and signal transfer in an interlayer ionospheric waveguide. Experiments on Alaska-Antarctica path showed that signal level at a receiving site is de-termined by heating wave parameters. In this case we did not study the character of its level change with time, i.e. possible fading, that is very important for radio-engineering systems. It is known that fading is determined by dimensions and space distribution of irregularity. Observations over EISCAT experiments make it possible, to some degree, to show the character of a scattered signal and the topology of ionospheric magnetically-oriented irregularities in the area of active impact on the ionosphere.
Modeling of fracture concentration by Sel’kov fractional dynamic system
Authors: Parovik Roman , Rakhmonov Zafar , Zunnunov Rakhimzhon
Published: October 2020

Microseismic phenomena are studied by a Sel’kov generalized nonlinear dynamic system. This system is mainly applied in biology to describe substrate and product glycolytic oscillations. Thus, Sel’kov dynamic system can also describe interaction of two types of fractures in an elastic-friable medium. The first type includes seed fractures with lower energy and the second type are large fractures which generate microseisms. The first type of fractures are triggers for the second type of fractures. However opposite transition is possible. For example, when large fractures lose their energy and partially become seed ones. After their concentration increase, the process repeats providing auto oscillation character of microseism sources. Generalization of Sel’kov dynamic system is its analogue which is based on hereditarity. Hereditarity is studied within hereditary mechanics and it shows that a dynamic system can “remember” for some time the impact which was made upon it. It is typical for viscoelastic and yielding mediums. The Sel’kov generalized dynamic system will be called Sel’kov fractional dynamic system as long as from the point of view of mathematical description, it can be represented in the form of a system of differential equations with fractional derivatives. Fractional derivative orders are associated with system hereditarity and are responsible for energy dissipation intensity emitted by first- and second-type fractures. In the paper, the Sel’kov fractional dynamic model was numerically solved by Adams-Bashforth-Moulton method. Oscillo-grams and phase trajectories were plotted. It was shown that fractional dynamic model may have relaxation and damped oscillations.
Quantum model of the magnetic field of the Hot Expanding Earth
Authors: Kuznetsov Vladimir
Published: October 2020

Principally new quantum model of the magnetic field of the Hot Earth [1] is proposed here. The model proceeds from the generation scheme of the Earth magnetic field (EMF) reported at the conference in 2019 [2], where crucial role of quantum entanglement (QE) of the inner G-core matter for EMF generation under the Hall effect was first evidenced. With regard to my impact into geodynamics of the Hot Earth [3] and quantum geophysics [4] the improved version of [2] is presented here. The justification for the model of EMF generation given in the encyclopedia of Geomagnetism [5] due to the daily rotation of the DEL (double electric layer), exciting a weak field and its amplification by the Hall current is first used here.
Relaxation oscillations in energy active zones
Authors: Shevtsov Boris
Published: October 2020

Relaxation oscillations in energy active natural zones are considered as causes of sudden catastrophes. A general approach to the study of dynamical systems of a fast-slow type is proposed, the relaxation oscillations of which give an adequate description of catastrophic events. The general properties of such systems are discussed using the example of solar activity and geomagnetic dynamo. The analogies between magnetic dynamos, laser systems, charge particles precipitation in the ionosphere, lightning discharges and earthquakes are considered. It is shown that these analogies are based on the presentation of various natural phenomena using dynamic systems of a fast-slow type.
Réponse sous impact de murs pare-blocs
Authors: Furet Agathe , Lambert Stephane , Villard Pascal , Jarrin Jean-Philippe , Lorentz Julien
Published: October 2020

Cet article présente l’étude du comportement dynamique de murs innovants de protection contre les chutes de blocs constitués de blocs en béton liés entre eux par un assemblage d’armatures. Les différents modes de déformation des murs et l’influence de la géométrie des murs sur leur réponse en déplacement sont étudiés par la réalisation d’impacts sur des murs à échelle 1/4, dans des configurations variées. Un modèle numérique basé sur une approche tridimensionnelle et continue, représentant de manière réaliste les différents constituants de la structure et leurs interactions, est ensuite proposé. Les résultats numériques concernant le déplacement de l’ouvrage sont confrontés aux résultats expérimentaux. Enfin, la dissipation d’énergie au sein de l’ouvrage est abordée, en considérant les différents mécanismes dissipatifs et leur contribution.
Investigation on hard turning temperature under a novel pulsating MQL environment: An experimental and modelling approach
Authors: Roy Soumikh , Kumar Ramanuj , Sahoo Ashok Kumar , Pandey Anish , Panda Amlana
Published: October 2020

Generation of total heat in hard turning largely influenced the cutting tool wear, tool life and finishing quality of work-surface. Thus, the measurement of this heat in terms of temperature becomes a necessity for achieving favourable machining performances. Therefore, this work presents a novel study on temperature measurement in three different zones during hard turning operation of 4340 grade steel under pulsating MQL environment. Temperatures are measured at three different locations namely chip-tool interface, flank face, and machined work surface (near to tool-work contact) and the location wise temperature is termed as chip tool interface temperature (T), flank face temperature (Tf) and machined work surface temperature (Tw) correspondingly. The temperature T and Tf are measured with help of K-type thermocouple while Tw is measured by Fluke make infra-red thermal camera. Pulsating MQL significantly reduced the temperature as the maximum temperature is noticed 110 °C which corresponds to chip-tool interface temperature (T) at highest speed (200 m/min) condition. In each test, the order of temperature follow the trend as: T > Tf > Tw. Considering average of all 16 temperatures, T is 14.42% greater than Tf and 39.36% larger than Tw while Tf is 21.79% greater than Tw. Experimental results concludes that the cutting speed is the most influencing factor followed by depth of cut for both T and Tf, whereas depth of cut is the most influencing factor for Tw. Further, these temperatures are predicted using linear regression, and absolute mean error (MAE) for responses T, Tf, and Tw is noticed as 1.848%, 0.542%, and 3.766% individually. Additionally, the optimum setting of input terms are estimated using WPCA (weighted principal component analysis) and found to bedc1(0.1 mm) − fr2(0.08 mm/rev) −vc2(100 m/min) − Pt2(2 s).
Dynamic channel decision-making of fresh agricultural product companies considering consumer convenience preferences
Authors: Yan Bo , Han Liguo , Chen Yanru , Liu Si
Published: October 2020

This paper studies the strategic channel decision-making of fresh agricultural product enterprises from the perspective of consumer convenience preferences. This research is carried out under the background of the upgrading of domestic consumption and the explosion of stay-at-home economy in China in recent years. In this paper, consumers are segmented firstly according to their different preference for consumption time, namely, convenience preference. Then, a channel decision model which considers the consumer convenience sensitivity and the inconvenience cost is proposed. Finally, the optimal wholesale price and delivery lead time of the supplier and the service level decision of the retailer are obtained by using backward induction method. The results show that under different market conditions, the supplier can adopt three equilibrium strategies: NR (No Retailer), CP (Capture Profit) and SP (Share Profit). With the change of inconvenience cost, the equilibrium state of supply chain will also change. Fresh agricultural product companies can choose different strategies to maximize their revenue according to different markets.
Lessons learned from predictions of Solar Cycle 24
Authors: Pesnell W. Dean
Published: October 2020

Solar Cycle 24 has almost faded and the activity of Solar Cycle 25 is appearing. We have learned much about predicting solar activity in Solar Cycle 24, especially with the data provided by SDO and STEREO. Many advances have come in the short-term predictions of solar flares and coronal mass ejections, which have benefited from applying machine learning techniques to the new data. The arrival times of coronal mass ejections is a mid-range prediction whose accuracy has been improving, mostly due to a steady flow of data from SoHO, STEREO, and SDO. Longer term (greater than a year) predictions of solar activity have benefited from helioseismic studies of the plasma flows in the Sun. While these studies have complicated the dynamo models by introducing more complex internal flow patterns, the models should become more robust with the added information. But predictions made long before a sunspot cycle begins still rely on precursors. The success of some categories of the predictions of Solar Cycle 24 will be examined. The predictions in successful categories should be emphasized in future work. The SODA polar field precursor method, which has accurately predicted the last three cycles, is shown for Solar Cycle 25. Shape functions for the sunspot number and F10.7 are presented. What type of data is needed to better understand the polar regions of the Sun, the source of the most accurate precursor of long-term solar activity, will be discussed.