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Alkali-activated slag recycled coarse aggregate concrete (AAS-RAC) is a novel type of green building material with significant growth potential, utilizing waste slag and construction waste effectively. However, its large shrinkage and poor toughness limit its further utilization. Adding fiber is the crucial way to limit its shrinkage. Therefore, the effects of fiber type and content on the shrinkage performance of AAS-RAC were systematically studied. The results show that the incorporation of recycled aggregate increases the shrinkage of AAS-RAC, and AAS-RAC of full recycled aggregate is 59% higher than that of undoped aggregate. The addition of steel fiber, polypropylene fiber and basalt fiber can effectively reduce the shrinkage of AAS-RAC. Among them, steel fiber has the best inhibition effect, and 0.6% steel fiber can reduce the shrinkage of AAS-RAC by 30.6%. The AAS-RAC shrinkage model considering the influence of fiber content and recycled aggregate is established. The research results provide an effective way to reduce the shrinkage of AAS-RAC. [ABSTRACT FROM AUTHOR]

To realize the large-scale utilization of municipal solid waste incineration (MSWI) fly ash in the field of building materials and to reduce the cost of coal mine backfill mining, the effects of the mixing ratio of cementitious materials, the particle size distribution of aggregates, and the amount and mass concentration of cementitious materials on the properties of backfill materials were experimentally investigated, and the microstructure of the hydration products was analyzed. The results showed that as the mass ratio of MSWI fly ash to bottom ash increased, the rate of expansion of the cementitious system continued to increase, and the compressive strength of the cementitious system continued to decrease. The Al (aluminum) and AlN (aluminum nitride) in the fly ash reacted with water to generate gas, causing the expansion of the cementitious materials; NaOH increased the alkalinity of the solution, which promoted the formation of more bubbles, thereby improving the expansion performance of the cementitious material. When the content of NaOH was 0.9%, the sample rate of expansion could reach 15.9%. The addition of CaCl2 promoted the early hydration reaction of the cementitious material, forming a dense microstructure, thus improving the early strength and rate of expansion of the cementitious material. The compressive strength of the backfill body increased as the fractal dimension of the aggregate particles increased, and the particle grading scheme of group S1 was optimal. The 1-day, 3-day, and 28-day strengths of the backfill body of group S1 reached 0.72 MPa, 1.43 MPa, and 3.26 MPa, respectively. It is recommended to choose a backfill paste concentration ranging between 78.5% and 80% and a reasonable amount of cementitious material between 20% and 25%. After the MSWI fly ash was prepared as a backfill material, the leaching of potentially harmful elements in the fly ash was greatly reduced, and the concentration of dioxin was reduced to 13 ng TEQ/kg. This was attributed to the dilution of the cement, the physical encapsulation of gel products, and the isomorphous replacement of Ca2+ in calcium aluminate chloride hydrate. [ABSTRACT FROM AUTHOR]

The dowel-bearing properties of a newly laminated flattened-bamboo (LFB) composite for engineering use was studied in this research by using the 5% bolt diameter offset method. The effects of specimen dimensions, bolt diameter, density, and bolt placed direction were included. Computed tomography (CT) and scanning electron microscope (SEM) were used to identify the failure type. The test results indicate that the parallel-to-grain dowel-bearing strength of LFB generally increased with an increasing density. When the bolt was placed along the LFB's radial direction, the parallel-to-grain dowel-bearing strength approximately remained a constant (52 MPa) with the change of specimen dimensions and bolt diameter, while when the bolt was along the tangential direction, the dowel-bearing strength increased with the raising ratio of specimen thickness and bolt diameter. The first failure type was a crushing failure of bamboo fiber underneath the bolt, it happened when bolt diameter was small (12 mm and 14 mm) and placed along LFB's radial direction. The second type was a splitting failure due to the lateral force generated by the bolt embedded into specimen, bamboo fiber splitting failure dominated for specimens with bolt along radial direction, while when bolt along tangential direction, glue layer splitting happened. The measured dowel-bearing strength was compared to the predictions obtained from equations in current wood specifications and articles. The results indicated that, except for the predicted values from the NDS equation (max error = 36%), which showed relatively reasonable agreement with the test values, the remaining predicted values exhibited discrepancies with the test values. To obtain proper predicted values, equations include density and ratio of specimen thickness and bolt diameter were proposed for calculation of LFB's parallel-to-grain dowel-bearing strength. [ABSTRACT FROM AUTHOR]

Alite-ye'elimite-belite-ferrite cement (AYBFC) integrates the advantages of calcium sulfoaluminate cement and Portland cement, but its ultra-early strength needs to be further improved when applied to rush repair and construction works. In this study, the ultra-early strength of AYBFC was improved using lithium carbonate (Li2CO3) and superplasticizer. The results showed that an appropriate amount of Li2CO3 could significantly improve the ultra-early strength of AYBFC, since it was capable of promoting the hydration reaction of AYBFC. After polycarboxylate superplasticizer was doped on this basis, the ultra-early compressive strength of AYBFC was further improved. This was because the superplasticizer could markedly enhance the matrix compactness despite its inhibitory effect on the hydration reaction of cement and the generation of hydration products. [ABSTRACT FROM AUTHOR]

The key to the stable performance of water-based drilling fluid at high temperature is related to the dispersion state of core colloidal particles, but the influence of the dispersion state of colloidal particles is very complicated. For the core components of water-based drilling fluid, the shear stress-strain temperature curve of bentonite colloid was obtained through high-temperature and high-pressure rheological testing, and the particle size distribution of colloidal particles was tested after different temperature effects. The dispersion, flocculation, and aggregation states and formation mechanisms of clay mineral colloidal particles were analyzed within the temperature range of room temperature to 220 ℃. In addition, the high temperature stability mechanism of porous fibrous clay mineral colloid rich in magnesium was revealed from a microscopic perspective by means of SEM test and clay mineral layer structure analysis. At the same time, based on a comprehensive analysis of the changes in rheological properties and filtration loss before and after high-temperature hot rolling, the interaction mechanism between bentonite/composite clay minerals and polymer based treatment agents at high temperatures is revealed from the perspectives of clay mineral structure characteristics, polymer chain breakage, adsorption characteristics, etc. Combined with experimental results, it is clear that low concentration bentonite/sepiolite composite colloids have significant high-temperature stability advantages, which provides theoretical support for the construction of ultra-high temperature water-based drilling fluid. [ABSTRACT FROM AUTHOR]

The fatigue performance of cementitious composites that affects the service life of structures is particularly sensitive to the initial defects in cementitious matrix and interfacial transition zone. Nano‐ZrO2 (NZ), characterized by high strength and toughness as well as good dispersibility, can improve the compactness of cementitious composites. This paper investigated the modifying effect and mechanisms of NZ on the compressive fatigue performance of cementitious composites, including fatigue life, strength, and deformation behaviors. The experimental results show that adding NZ extends the fatigue life of cementitious composites by an order of magnitude and increases the fatigue failure strain by 11.9%. The microstructural analysis verifies that NZ can deflect the fatigue micro‐cracks, fill the micro‐pores and reduce the growth space of CH crystal size. The modified microstructures potentially lead to fatigue of cementitious composites starting from generating more nano‐cracks in both cementitious matrix and interfacial transition zone, thereby improving the fatigue performance of the composites. Highlights: Nano‐ZrO2 (NZ) is added into concrete to improve compressive fatigue propertyThe fatigue life and failure strain of concrete are enhanced by the addition of NZThe morphology of fatigue fracture surface of concrete with/without NZ is observedThe fatigue equation of cementitious composites with/without NZ is developed [ABSTRACT FROM AUTHOR]

This article reports a comparative analysis between glass waste and fly ash (which is the most studied waste for the alkali-activated products) to measure their effectiveness as a sole precursor to produce geopolymers. Globally, around 11.4 million tonnes of glass waste is generated per annum, and this needs to be managed properly. To address this issue, in this study, glass waste which was mostly manufactured bottles and containers was used in pulverized form. The molarity of the sodium hydroxide (NaOH) solution was kept as 6 M, 8 M, and 10 M. The sodium silicate-to-sodium hydroxide (Na2SiO3/NaOH) solution mix ratio was varied between 1.5 and 3.5. Mechanical (compressive and flexural strength) and durability (resistance to different levels of sulfuric acid) aspects were studied along with micro-analysis (structural, elemental, and thermal). Controlled ambient temperature curing was followed for all the samples. Our findings showed that mechanical properties were dependent on the molarity, silicate modulus, and alkaline mixture (AM) ratio. The glass waste showed substantial amount of long-term strength development over fly ash with a maximum compressive strength gain at 28 d and 90 d curing age of 90% and 194% for 8M1.5AM and 6M1.5AM mixture, respectively. For flexural strength, it was 49% and 62% gain at 28-d and 90-d curing, respectively, for 10M1.5AM mixture. The glass waste also offered relatively higher resistance to acid attack with a maximum compressive strength loss of 61% and 55.7%, whereas fly ash-based mixtures recorded 75% and 71.73% reduction for 5% and 3% H2SO4 attack for 28 d, respectively. Field emission scanning electron microscopy (FE-SEM) revealed that the glass waste specimens were more compact than fly ash-based specimens. Thermogravimetric analysis (TGA) results indicate that glass waste-based geopolymers are more thermally resistant than fly ash-based geopolymers when exposed to a systematic increment in temperature. Ultimately, promising results in terms of mechanical and durability aspects propose the use of glass waste as a binder in geopolymeric masonry mortar applications. Glass waste has a full potential to be a sole precursor to produce geopolymer under ambient temperature curing conditions. This will contribute towards sustainable environment by paving path for an effective utilization of the glass waste. [ABSTRACT FROM AUTHOR]

To realize the large-scale utilization of municipal solid waste incineration (MSWI) fly ash in the field of building materials and to reduce the cost of coal mine backfill mining, the effects of the mixing ratio of cementitious materials, the particle size distribution of aggregates, and the amount and mass concentration of cementitious materials on the properties of backfill materials were experimentally investigated, and the microstructure of the hydration products was analyzed. The results showed that as the mass ratio of MSWI fly ash to bottom ash increased, the rate of expansion of the cementitious system continued to increase, and the compressive strength of the cementitious system continued to decrease. The Al (aluminum) and AlN (aluminum nitride) in the fly ash reacted with water to generate gas, causing the expansion of the cementitious materials; NaOH increased the alkalinity of the solution, which promoted the formation of more bubbles, thereby improving the expansion performance of the cementitious material. When the content of NaOH was 0.9%, the sample rate of expansion could reach 15.9%. The addition of CaCl2 promoted the early hydration reaction of the cementitious material, forming a dense microstructure, thus improving the early strength and rate of expansion of the cementitious material. The compressive strength of the backfill body increased as the fractal dimension of the aggregate particles increased, and the particle grading scheme of group S1 was optimal. The 1-day, 3-day, and 28-day strengths of the backfill body of group S1 reached 0.72 MPa, 1.43 MPa, and 3.26 MPa, respectively. It is recommended to choose a backfill paste concentration ranging between 78.5% and 80% and a reasonable amount of cementitious material between 20% and 25%. After the MSWI fly ash was prepared as a backfill material, the leaching of potentially harmful elements in the fly ash was greatly reduced, and the concentration of dioxin was reduced to 13 ng TEQ/kg. This was attributed to the dilution of the cement, the physical encapsulation of gel products, and the isomorphous replacement of Ca2+ in calcium aluminate chloride hydrate.

This paper presents an evaluation of the pull-out behaviour of tyre strip-reinforced granular soil. The three-dimensional discrete element method (3D DEM) and laboratory testing were used to systematically calibrate the soil particles and the tyre strip based on their stress-strain relationship, tensile stiffness, and interface shear strength. Particle shapes were considered during sand calibration. The scaled pull-out resistance was found to match that of the experimental data. Contributions of the sectional interface shear force to the total pull-out resistance were calculated to explain the progressive failure mechanism mobilised at the tyre-sand interface. The shear force along the tyre strip was not uniformly distributed but higher in the middle portion of the tyre strip. It gradually extended towards the front end of the tyre strip before global interface slipping failure occurred. Comparing the pull-out behaviour of extensible and inextensible tyre strips, the elastic deformation of the tyre strip delayed the occurrence but not the magnitude of peak pull-out force. Micro-mechanical interactions between tyre strip and sand during shear mobilisation were discussed, and induced anisotropy was revealed. The experimental and DEM investigation results in this study provide researchers with an improved understanding of tyre-soil interaction under pull-out loads. [ABSTRACT FROM AUTHOR]

Alite-ye’elimite-belite-ferrite cement (AYBFC) integrates the advantages of calcium sulfoaluminate cement and Portland cement, but its ultra-early strength needs to be further improved when applied to rush repair and construction works. In this study, the ultra-early strength of AYBFC was improved using lithium carbonate (Li2CO3) and superplasticizer. The results showed that an appropriate amount of Li2CO3 could significantly improve the ultra-early strength of AYBFC, since it was capable of promoting the hydration reaction of AYBFC. After polycarboxylate superplasticizer was doped on this basis, the ultra-early compressive strength of AYBFC was further improved. This was because the superplasticizer could markedly enhance the matrix compactness despite its inhibitory effect on the hydration reaction of cement and the generation of hydration products.

Three kinds of silane coupling agents (KH550, KH560, KH570) were used to modify graphene oxide (GO). The effects of different modification methods and addition amounts on the physical properties of the composite gasket were studied, and the microscopic analysis was carried out by FTIR and SEM. The results showed that the modification method, addition amount and modification method and addition amount of GO had significant effects on the compression rate, tensile strength and weight gain rate of the composite gasket after impregnating ASTM fuel oil, but the effect of the rebound rate of the composite gasket was not significant. The modification method and addition amount of GO had no significant effect on the thickening rate of the gasket. The gasket prepared with 0.15% GO modified by KH570 has the maximum rebound rate, tensile strength and weight gain rate; when the addition amount was more than 0.15%, the compression rate, spring back rate, tensile strength, weight gain rate and thickening rate decreased.GO modified by KH570 was added to the composite gasket, which promoted the strong micro-physical and chemical interaction between the component materials. When the content of GO modified by KH570 was 0.15%, the composite material showed the best effect in micro-physical and chemical interaction. Overall, the gasket prepared with 0.15% GO modified by KH570 has the best comprehensive performance. [ABSTRACT FROM AUTHOR]

Inorganic repair materials have significant advantages such as high durability, high strength, and good corrosion resistance. However, their low bonding strength and inadequate tensile performance are clear disadvantages, which often results in problems like cracking, delamination, and insufficient repairing strength. In the current study, a new repair material is developed, which enhances the interfacial bonding performance of carbon nanotubes (CNTs) repair materials by introducing ethylene vinyl acetate (EVA). The bonding strength of composite specimens was tested by splitting tensile test. Then the microstructure analysis of the repaired materials was conducted by X-ray computed tomography, backscattered electron imaging, and scanning electron microscopy. The phase composition of the repair material was further analyzed by Fourier transform infrared spectroscopy. Finally, the bonding mechanisms of EVA reinforced CNTs repair materials were discussed. The results indicate that the interaction between EVA and CNTs can enhance the bonding performance of repair materials. Additionally, the polymer film formed by EVA within the repair material can refine the pores, thereby reducing the porosity of the interfacial transition zone and that of repair materials. The electrostatic repulsion between EVA and CNTs contributes to the uniform dispersion of CNTs within repair materials. [Display omitted] • A new ethylene vinyl acetate reinforced carbon nanotube repair material is developed. • Incorporating EVA into the developed CNTs repair material improves the bonding performance. • Addition of EVA can effectively reduce the porosity and improve the compactness of ITZ. • The electrostatic repulsion between EVA and CNTs facilitates dispersibility of CNTs. [ABSTRACT FROM AUTHOR]

The combination of experimental programs and finite element numerical methods is adopted to explore the durability of WBC (waste brick concrete). Rapid freeze-thaw and flexural tests are performed with the content of WBCA (waste brick coarse aggregate) and the number of freeze-thaw cycles as variables. Freeze-thaw damage mechanisms at the microscopic interfaces of recycled concrete are revealed by scanning electron microscopy. The evolution laws of relative dynamic elastic modulus, mass loss rate, and flexural and tensile strength loss rate are analyzed. Combined with numerical simulations, the temperature stress distribution and three-point bending damage law of concrete with 100 % WBCA content at different freeze-thaw times are shown, and practical examples are verified. Results showed that WBC with high WBCA content has poor freeze-thaw resistance. Furthermore, WBC's freezing resistance and bending properties deteriorate as the number of freeze-thaw cycles increases. Possible damaged locations in the concrete are determined by stress analysis. The finite element model can predict the flexural performance of WBC better with an error of 4.5 % for the peak load and 3.5 % for the peak displacement of the beam. Therefore, the presented model can also be used to predict the performance of concrete after freezing and thawing under any WBCA replacement rate.

Comprehensive micro‐analyses were conducted to identify different pigments and dyes used in painted figurines of the Tang Dynasty unearthed from Astana Tombs, located along the ancient Silk Road. Interestingly, a mixture of lazurite and indigo was first discovered on a painted figurine to create a special blue hue, demonstrating that ancient Gaochang craftsmen were already skilled in using mixed colorants. Moreover, superimposition techniques were as well applied in these painted figurines, such as hematite or cinnabar overlaid on red lead. Despite the lack of unambiguous restoration records in the last century, multiple synthetic organic colorants used for repainting the lokapala figurine were successfully identified by Raman spectroscopy and ultra‐performance liquid chromatography‐tandem mass spectrometry (UPLC‐MS/MS), which should be helpful for the retrospective documentation of the restoration history of these artworks. These investigations towards archaeological materials can provide precise historical facts about the artworks and fundamental knowledge for their conservation. [ABSTRACT FROM AUTHOR]

In order to improve the durability of asphalt pavement and prolong the service life of heavy traffic asphalt pavement, graphene oxide (GO) and rubber powder (RP) were used as composite modifiers to modify matrix asphalt. The high-temperature rheological properties of composite-modified asphalt at different temperatures and frequencies were analyzed. The influence of different stress levels on the viscoelastic properties of composite-modified asphalt was evaluated. The low-temperature rheological properties of composite-modified asphalt were studied. The difference between RP-modified asphalt and GO/RP composite-modified asphalt was analyzed, and the mechanism of GO and RP on asphalt modification was explored. The results show that the composite-modified asphalt has good rheological properties at low temperature, relatively smooth surface and stable network structure, which improves the segregation problem of RP in matrix asphalt. At present, GO and RP are rarely used as composite modifiers to modify matrix asphalt at home and abroad, which is an innovation in material selection. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Early childhood education (ECE) presupposes a balance between emotionally supportive interaction and pre-academic teaching instruction, and research indicates an increasing pressure on preschool teachers' communicative competence. This study focuses on the functions of emotions in the teacher–child relationship in a situated context. Such studies are scarce in the research on ECE, which mainly concerns children's socioemotional learning. Using a micro-sociological approach, characterized by an in-depth analysis of interaction, we explore the ways in which emotions may foster conformity in goaloriented preschool activities. Verbal and nonverbal utterances between a preschool teacher and a child in a video-recorded episode were transcribed and analyzed meticulously. The findings reveal an informal, subtle system of social sanctions within which the emotions of shame and pride have important functions, which leads to social adaptation to goal-oriented expectations. The study also discusses how emotional processes during interaction can be understood in light of the institutional context of current ECE. [ABSTRACT FROM AUTHOR]

In order to solve the problem of poor crack resistance and frost resistance of semi-rigid base, rubber powder and retarder were added to a semi-rigid base mixture. First, 61 mixing ratios were determined. Then, through the unconfined compressive strength, splitting strength, and other tests, the mechanical, crack, and frost resistance properties of the retarded composite semi-rigid base coarse mixture with rubber powder were studied. Finally, the macro and micro properties of the two kinds of admixture composite semi-rigid base coarse mixtures were studied by means of SEM and industrial CT. The results show that rubber powder and retarder can effectively improve the cracking and freezing resistance of the mixture. After five freeze–thaw cycle tests, the strength of the retarded composite semi-rigid base material mixed with rubber powder decreased slightly compared with the mixture without additives. It can be seen that rubber powder improved the frost resistance of the mixture. When the content of rubber powder was 1.5%, the BDR value of the mixture increased by 8.8%. With the increase of unconfined compressive strength, splitting strength, and flexural tensile strength at 28 d and 90 d, it was found that the retarder improved the middle and late strength of the mixture. When the content of retarder was 0.09%, the increase of unconfined compressive strength at 28 d reached 3.9%. The addition of rubber powder and retarder improved the distribution of internal pores, the proportion of large pores decreased, and the proportion of small pores increased. The retarder changed the morphology of hydration products, formed a dense network supporting structure, further refined the pores, and reduced the porosity of the mixture. The proportion of pores with a volume greater than 100 mm3 in the total pore volume decreased by 26.01%, and the proportion of medium pores increased by 13.07%, thereby improving the mechanical properties of the mixture. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Non-metallic fractions (NMFs) from waste printed circuit boards (PCBs) are mostly composed of cured resin and fiber. In this study, NMF material from a PCB was ground into powder and added into matrix asphalt to produce PCB-NMF-modified asphalt. To improve the compatibility of PCB-NMF and asphalt, a compatibilizer consisting of tung oil and glycerol was also developed. The optimum compatibilizer content was determined to be 8% by weight of the PCB-NMF through a series of laboratory tests, including the softening point, penetration, ductility, and softening point difference (SPD). The micro-mechanism of NMF powder-modified asphalt was analyzed through Fourier transform infrared spectroscopy (FTIR) and a scanning electron microscope test (SEM). The performances of PCB-NMF-modified asphalt were evaluated by the dynamic shear rheology (DSR) test and the low-temperature bending beam rheometer (BBR) test. The optimum compatibilizer content was 8% by weight of the NMF powder and the optimum content of NMF powder was determined to be 30% by weight of the asphalt based on a comprehensive evaluation. The results show that PCB-NMF can significantly improve stiffness, rutting resistance, high-temperature stability, and temperature sensitivity of asphalt material at an appropriate content. The BBR tests revealed that PCB-NMF slightly weakened the cracking resistance of asphalt at low temperatures. The SEM test showed that the addition of a compatibilizer can increase the compatibility by making the NMF powder evenly dispersed. The FTIR test results implied that a chemical reaction may not have happened between PCB-NMF, compatibilizer, and the matrix asphalt. Overall, it is a promising and sustainable way to utilize PCB-NMF as a modifier for asphalt material and reduce electronic waste treatment at a low cost. [ABSTRACT FROM AUTHOR]

The strengthening application of brick concrete recycled coarse aggregate (BCRCA) has become a “troublesome issue.” In this sense, an in-depth study on the strengthening method of BCRCA is needed. In order to improve the strengthening effect of BCRCA and perform the large-scale application of brick concrete waste, the strengthening method of BCRCA was investigated. Briefly, the performance of BCRCA was initially analyzed. Then, the pore characteristics of BCRCA were tested by CT scanning technology. The evaluation index of filling saturation was proposed. Finally, the BCRCA was strengthened by the negative pressure, and the influences of key parameters such as negative pressure, negative pressure time, negative pressure temperature, and stirring times on the strengthening effect were investigated. The test results showed that the best performance can be obtained by using the following parameters: negative pressure from −55 kPa to −80 kPa, the negative pressure time from 6 to 14 min, the negative pressure temperature from 40 to 80°C, and the stirring times from 1 to 4 times. Combined with the influence of negative pressure strengthening process parameters on filling saturation, it can be determined that a negative pressure of −75 kPa, a negative pressure time of 12 min, and a negative pressure temperature of 70°C with two times of stirring were the best negative pressure strengthening parameters. The unconfined compressive strength and indirect tensile strength reached 4.9 and 0.55 MPa, respectively, when the reinforced BCRCA was used for the cement-stabilized macadam. Therefore, the negative pressure strengthening process parameters determined in this study can achieve a good strengthening effect.

• The chemical processes of H 2 S-induced cement corrosion are studied. • The impact of high-temperature condition on H 2 S corrosion is analyzed. • The mechanical properties of H 2 S-corroded cement are investigated. H 2 S, a highly toxic and corrosive substance present in geothermal reservoirs, can significantly reduce the durability of geothermal well cement. High temperature is a prominent environmental characteristic in the extraction of geothermal resources; however, current research primarily focuses on the corrosive effects of H 2 S on cement under moderate to low temperatures. This study employed Class G oilwell cement to investigate the corrosion of H 2 S on cement under high temperature. The experiments were conducted in a high-temperature reaction vessel. The effects of H 2 S on cement structure, chemical composition, and mechanical strength were analyzed under high-temperature conditions via SEM-EDS, XRD, FTIR, nanoindentation, and unconfined compressive strength tests. The results indicate that the corrosive effects of H 2 S lead to formation of different reaction layers within the cement structure, forming of microcracks, and changes in material composition. Within the cement, secondary minerals with weaker bonding properties, such as pyrite, pyrrhotite, and gypsum, are generated. Simultaneously, the compressive strength of the samples decreases. The surface nano-hardness and elastic modulus of the cement decrease, while there is a significant increase of nano-hardness and elastic modulus in the interior of cement, due to changes in structure and chemical composition. In summary, high temperature in geothermal applications reduces the level of H 2 S-induced cement corrosion due to inhibition of ettringite formation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The CUO has systemic vertical variations in mineral assemblages and pitchblende geochemistry. • The vertical variations were caused by the ascent of deep oxidizing fluid and decreased upwardly during U mineralization. • REE of pitchblende could be used to guide deep uranium exploration. The Changjiang uranium (U) orefield in northern Guangdong (South China) contains several important granite-related uranium deposits, including the Mianhuakeng deposit. The hydrothermal evolution and mineralization mechanism of the deposit remain unclear, and hence in this study we analyzed the mineral compositional variations of pitchblende from different elevation (−300 to −50 m) in the orebody at Mianhuakeng deposit. The results indicate that with decreasing depth, the hydrothermal mineral assemblage changes from a reducing one (pitchblende, pyrite, and chlorite) to a moderately oxidizing one (pitchblende, coffinite, hematite, and goethite). The contents of U, Sr, ∑REE, U/Th, and LREE/HREE ratios in the pitchblende decrease (whereas the Cu-Pb-Zn-Ni-Co-Sc-Rb contents increase) progressively with decreasing depth. Also, Ce anomaly (Ce/Ce*) changes from positive to negative, and Eu anomaly (Eu/Eu*) becomes more negative with decreasing depth. We interpreted such vertical variations to be caused by the ascent of deep, mid-to-high temperature, highly-oxidizing ore-forming fluid, which was reduced by early-stage reducing minerals in the wallrock, a process that also formed the mineralization at Changjiang. In addition, the pitchblende REE distribution patterns and Eu/Eu* at depth (−300 m) resemble those of the Zhuguang pluton, indicating that the ore-forming materials were originated from the U-bearing granite wallrocks. Therefore, the Ce/Ce* and Eu/Eu* variations of pitchblende can be used to guide deep uranium ore exploration. [ABSTRACT FROM AUTHOR]

The following paper describes the quantitative analysis of wood samples of black pine (Pinus nigra) using a benchtop Micro X-ray Fluorescence (μXRF) device for elemental analysis and surface scanning. Calibration of the device for quantitative elemental analysis and local density measurements of wood was performed by utilizing characteristic X-ray line intensities and backscattered radiation intensities. The influence of a variable wood density and matrix composition on X-ray spectra were studied with Monte Carlo calculations. The Monte Carlo model was validated with a set of reference materials possessing known compositions and densities. It has been demonstrated that Monte Carlo simulations with the MCNP code, along with, only one reference material are required for the quantitative XRF analysis. The backscattered radiation in the XRF spectra can be used for simple recognition of individual tree rings and their corresponding shapes. • Quantitative XRF micro-analysis of wood was introduced. • Effect of wood density in XRF was corrected with Monte Carlo method. • Local wood density was determined with X-ray densitometry. • Hidden tree rings in wood were recognized and their shapes visualised. [ABSTRACT FROM AUTHOR]

One of the main challenges in group therapy with drug-addicted patients is collective pseudomentalization, i.e., a group discourse consisting of words and clichés that are decoupled from any inner emotional life and are poorly related to external reality. In this study, we aimed to explore the phenomenology of pseudomentalization and how it was addressed by the therapist in an outpatient group for drug-addicted patients. The group was composed of seven members, and the transcripts of eight audio-recorded sessions (one per month) were rated and studied. The interventions of the therapist were measured with the mentalization-based group therapy (MBT-G) adherence and quality scale by independent raters. Two sessions, one with the highest and one with the lowest adherence, were selected, and the clinical sequences of pseudomentalization were analyzed in a comparative way. The findings revealed that pseudomentalization does occur as a collective phenomenon, akin to "basic assumptions" of Wilfred Bion, which we reconceptualized in this study. Any pseudomentalization seemed to be reinforced by the therapist when she was presenting frequent and long interventions, when abstaining from the management of group boundaries, when providing questions focused more on content than on the mental states of the group members, and when not focusing on emotions. However, the ultimate source of collective pseudomentalization seemed to be the fear of the group members of being overwhelmed by painful emotions, mental confusion, and a loss of identity. The findings also indicated that the principles of MBT-G may be a good antidote to pseudomentalization. [ABSTRACT FROM AUTHOR]

One of the main challenges in group therapy with drug-addicted patients is collective pseudomentalization, i.e., a group discourse consisting of words and clichés that are decoupled from any inner emotional life and are poorly related to external reality. In this study, we aimed to explore the phenomenology of pseudomentalization and how it was addressed by the therapist in an outpatient group for drug-addicted patients. The group was composed of seven members, and the transcripts of eight audio-recorded sessions (one per month) were rated and studied. The interventions of the therapist were measured with the mentalization-based group therapy (MBT-G) adherence and quality scale by independent raters. Two sessions, one with the highest and one with the lowest adherence, were selected, and the clinical sequences of pseudomentalization were analyzed in a comparative way. The findings revealed that pseudomentalization does occur as a collective phenomenon, akin to “basic assumptions” of Wilfred Bion, which we reconceptualized in this study. Any pseudomentalization seemed to be reinforced by the therapist when she was presenting frequent and long interventions, when abstaining from the management of group boundaries, when providing questions focused more on content than on the mental states of the group members, and when not focusing on emotions. However, the ultimate source of collective pseudomentalization seemed to be the fear of the group members of being overwhelmed by painful emotions, mental confusion, and a loss of identity. The findings also indicated that the principles of MBT-G may be a good antidote to pseudomentalization.

Wind turbine duct put forward higher requirements for the performance of grouting materials. In order to obtain more economical high strength grouting materials (HSG), three kinds of low price main components, cement, quartz sand (QS) and fly ash microspheres (MS) were utilized and developed. Macro performance and micro-analysis of the HSG were conducted. The macro performance tests revealed that the mix proportion of HSG is determined as, cement: QS: MS: superplasticizer: swelling agent = 80:10:10:0.3:0.12, water binder ratio is determined as 0.26. Compressive and flexural strength of the HSG exceeding 120 MPa and 20 MPa respectively. The HSG also showed good fluidity and homogeneity. The micro-analysis showed that a complete and continuous micro-structure was formed and interface transition zone could not be observed. XRD and TG-DSC results meant that the amount of AFt increased. On the contrary, the amount of Ca(OH) _2 decreased. pore diameter of the HSG was mostly 10 nm. The addition of swelling agent and MS did not changed the types of hydration products of HSG, but the pore structure was optimized. Due to the cheap components, HSG contributed higher profits with the lower price, and which perform good economic benefits and market competitiveness.

The main purpose of this study is to determine the metakaolin (MK) impacts on the concrete durability when the concrete is subjected to joint corrosion of SO42−,Mg2+ and, Cl−. Four groups of concrete test samples, which contained different MK contents, were designed and tested in order to see their physical property changes and macro-morphology differences during the cyclic corrosion process. And a series of approaches, including XRD, FTIR, SEM, and EDS, were applied to study the concrete phase composition changes and the micro-morphology features of all groups. According to the test results, when reaching 20 cycles, the concrete sample with 10% MK showed the best concrete physical properties; when reaching 120 cycles, the concrete with 5% MK content showed the best durability, produced similar amount of corrosion products to ordinary concrete, and presented relatively compacted micro-structure and small internal porosity. Mg2+ actually has a great impact on metakaolin. The corrosion product quantity increased significantly when MK admixture reached 15%. Due to the great number of produced M-S-H, the corrosive ions damaged the concrete for a second time, leading to serious aggregate peeling-off, powder surface of test samples, and porous micro-structure.

In order to improve the durability of asphalt pavement and prolong the service life of heavy traffic asphalt pavement, graphene oxide (GO) and rubber powder (RP) were used as composite modifiers to modify matrix asphalt. The high-temperature rheological properties of composite-modified asphalt at different temperatures and frequencies were analyzed. The influence of different stress levels on the viscoelastic properties of composite-modified asphalt was evaluated. The low-temperature rheological properties of composite-modified asphalt were studied. The difference between RP-modified asphalt and GO/RP composite-modified asphalt was analyzed, and the mechanism of GO and RP on asphalt modification was explored. The results show that the composite-modified asphalt has good rheological properties at low temperature, relatively smooth surface and stable network structure, which improves the segregation problem of RP in matrix asphalt. At present, GO and RP are rarely used as composite modifiers to modify matrix asphalt at home and abroad, which is an innovation in material selection.

In order to solve the problem of poor crack resistance and frost resistance of semi-rigid base, rubber powder and retarder were added to a semi-rigid base mixture. First, 61 mixing ratios were determined. Then, through the unconfined compressive strength, splitting strength, and other tests, the mechanical, crack, and frost resistance properties of the retarded composite semi-rigid base coarse mixture with rubber powder were studied. Finally, the macro and micro properties of the two kinds of admixture composite semi-rigid base coarse mixtures were studied by means of SEM and industrial CT. The results show that rubber powder and retarder can effectively improve the cracking and freezing resistance of the mixture. After five freeze–thaw cycle tests, the strength of the retarded composite semi-rigid base material mixed with rubber powder decreased slightly compared with the mixture without additives. It can be seen that rubber powder improved the frost resistance of the mixture. When the content of rubber powder was 1.5%, the BDR value of the mixture increased by 8.8%. With the increase of unconfined compressive strength, splitting strength, and flexural tensile strength at 28 d and 90 d, it was found that the retarder improved the middle and late strength of the mixture. When the content of retarder was 0.09%, the increase of unconfined compressive strength at 28 d reached 3.9%. The addition of rubber powder and retarder improved the distribution of internal pores, the proportion of large pores decreased, and the proportion of small pores increased. The retarder changed the morphology of hydration products, formed a dense network supporting structure, further refined the pores, and reduced the porosity of the mixture. The proportion of pores with a volume greater than 100 mm3 in the total pore volume decreased by 26.01%, and the proportion of medium pores increased by 13.07%, thereby improving the mechanical properties of the mixture.

Non-metallic fractions (NMFs) from waste printed circuit boards (PCBs) are mostly composed of cured resin and fiber. In this study, NMF material from a PCB was ground into powder and added into matrix asphalt to produce PCB-NMF-modified asphalt. To improve the compatibility of PCB-NMF and asphalt, a compatibilizer consisting of tung oil and glycerol was also developed. The optimum compatibilizer content was determined to be 8% by weight of the PCB-NMF through a series of laboratory tests, including the softening point, penetration, ductility, and softening point difference (SPD). The micro-mechanism of NMF powder-modified asphalt was analyzed through Fourier transform infrared spectroscopy (FTIR) and a scanning electron microscope test (SEM). The performances of PCB-NMF-modified asphalt were evaluated by the dynamic shear rheology (DSR) test and the low-temperature bending beam rheometer (BBR) test. The optimum compatibilizer content was 8% by weight of the NMF powder and the optimum content of NMF powder was determined to be 30% by weight of the asphalt based on a comprehensive evaluation. The results show that PCB-NMF can significantly improve stiffness, rutting resistance, high-temperature stability, and temperature sensitivity of asphalt material at an appropriate content. The BBR tests revealed that PCB-NMF slightly weakened the cracking resistance of asphalt at low temperatures. The SEM test showed that the addition of a compatibilizer can increase the compatibility by making the NMF powder evenly dispersed. The FTIR test results implied that a chemical reaction may not have happened between PCB-NMF, compatibilizer, and the matrix asphalt. Overall, it is a promising and sustainable way to utilize PCB-NMF as a modifier for asphalt material and reduce electronic waste treatment at a low cost.

This work explored the correlation among the physical and mechanical parameters of concrete in marine environments during corrosion. Concrete materials with varied water–cement ratios (w/c) were soaked in four kinds of simulated seawater, including a compound solution of sodium chloride (NaCl) and magnesium sulfate (MgSO4), a solution of MgSO4, a solution of sodium sulfate (Na2SO4), and clear water. The macroscopic physical and mechanical parameters, such as compressive strength, tensile strength, mass change and ultrasonic wave velocity, were measured. The damage mechanism of corrosion products and microstructures was analyzed using microscopic approaches including scanning electron microscopy (SEM), X-ray diffraction (XRD), etc. Linear correlation was carried out on the abovementioned physical parameters, and the results revealed that, during corrosion, the correlation between compressive and tensile strength and mass (excluding Na2SO4 solution) is positive (mostly highly correlated), while that with wave velocity is poor (mostly moderately correlated).

• C-S-H seeds and sulphoaluminate cement were used to prepared RH-UHPC. • The flexural load–deflection response of RH-UHPC was studied by AE technology. • The flexural failure pattern, strength, energy absorption capacity, and toughness index of RH-UHPC were investigated. • Micromorphology, phase composition, and pore structure of RH-UHPC were studied. With the increasing requirements for emergency repair projects, there is a pressing need for high-quality repair materials. In this work, a series of rapid hardening ultra-high performance concrete (RH-UHPC) were prepared by using C-S-H seeds and SAC as early-strength agents. The effects of these early-strength agents on RH-UHPC's flexural behaviors, including failure pattern, strength, energy absorption capacity, and toughness index, were investigated. Also, the variations of acoustic emission signals and microstructure were studied to provide a thorough insight into the influence of early-strength agents on RH-UHPC. The results show that C-S-H seeds and SAC exhibited a good effect on improving the 1-day flexural strength of RH-UHPC, but increased the risk of shear failure at 28 days. The flexural strength, energy absorption capacity, and toughness of RH-UHPC at 28 days were reduced by adding C-S-H seeds. However, combining C-S-H seeds with SAC alleviated this reduction. Moreover, incorporating early-strength agents enhanced the ringing counts, AE energy, damage rate, and the proportion of shear cracks. The noticeable increase in r value (i.e., RA/AF) judged the damage stage of RH-UHPC more reliably. Micro-analysis revealed that introducing C-S-H seeds increased the internal cracks and the Ca/Si ratio of C-S-H gel, but the hybrid of C-S-H seeds and SAC partially mitigated above problem. The incorporation of SAC notably increased the AFt content and decreased the CH content. C-S-H seeds presented little effect on the hydration degree of RH-UHPC, but roughened the pore size and enlarged the average pore size. [ABSTRACT FROM AUTHOR]

• Alkali-activated slag recycled aggregate concrete (AAS-RAC) is an achievable way of realizing the coordinated and effective disposal of industrial and construction solid wastes. • The mechanical properties of AAS-RAC under axial compression are comprehensively investigated. • The effects of recycled coarse aggregate and fiber on the axial compressive mechanical properties of AAS-RAC are discussed from the perspective of macro performance and microstructure. • The axial compression stress–strain model of fiber reinforced AAS-RAC is established. Fiber-reinforced alkali-slag recycled concrete, a novel green building material with high-efficiency solid-waste utilization, can effectively utilize waste slag and recover coarse aggregates. However, no relevant research has been conducted on the mechanical properties under axial compression. Therefore, this study investigated the influence of fiber type, fiber content, and recycled coarse aggregate content on the axial compression mechanical properties of fiber-reinforced alkali-slag recycled concrete. The results show that an appropriate amount of steel, basalt, and polypropylene fibers can effectively improve the axial compressive strength, peak compressive strain, and elastic modulus of alkali-activated slag recycled concrete. The axial compressive strength, peak compressive strain, and elasticity can be enhanced by 10.6–31.9%, 26.0–29.3%, and 1.4–69.1%, respectively. Basalt fibers had the worst effect, while steel fibers had the best effect. A small proportion of recycled coarse aggregate can slightly increase the axial compressive strength and peak compressive strain while significantly reducing the elastic modulus. An axial compression stress–strain model of the fiber-reinforced alkali-slag recycled concrete was established. These results provide basic theoretical support for the comprehensive and effective exploitation of waste slag and building waste. [ABSTRACT FROM AUTHOR]

• The bonding properties between FCNTs repair mortar and fire exposed old mortar substrate has been investigated. • The bonding strength and microscopic test were performed to determine the reinforcing mechanism of FCNTs in the ITZ. • An effective prediction model is proposed to quantify the effects of porosity and different FCNTs on the interfacial bonding strength of composite specimens. Reinforced concrete structures need to be repaired after exposure to fire, in which the weakness of the interfacial transition zone between the repair mortar and the old concrete substrate is a crucial problem. Carbon nanotube can be added into repair mortar to address the above-mentioned problem because of its bridging, pore filling and nucleation effects. However, the bonding mechanism of functionalized carbon nanotube repair mortar and the old concrete is not yet fully understood. Therefore, this study investigates the bonding performance between different functionalized carbon nanotube repair mortar and old mortar substrate exposed to high temperature. Firstly, to evaluate the roughness of old mortar exposed to high temperature, three-dimensional microscope and mercury intrusion porosimetry were performed in this paper. Secondly, thermogravimetric analysis and X-ray diffraction were carried out to further analyze the phase composition of the repair mortar. Thirdly, microstructure of the interfacial transition zone was investigated by electron backscatter diffraction characterization and microhardness measurements. Fourthly, the bonding mechanism of interface between new and old mortar was discussed. The results show that the surface roughness of the old mortar can gradually increase with increasing of temperature, which improves the interfacial mechanical interlocking. The functionalized carbon nanotube can reduce the content and orientation of calcium hydroxide and improve the microhardness of the interfacial transition zone. Finally, an interfacial bonding strength prediction model considering porosity and the reinforcing effects of different functionalized carbon nanotube is proposed. The findings of current study can benefit further research and application of nanomaterials in the field of structural repair and maintenance. [ABSTRACT FROM AUTHOR]

The international trend of positioning the preschool as a pre-academic learning environment is challenging for preschool teachers, as it necessitates a balance between emotionally supportive interaction and goal-oriented learning instruction. However, previous research suggests that the complexities of such interactions need to be further studied. This article contributes by presenting a very detailed exploration of how social adaptation is pursued in a goal-oriented documentation activity. The study used a micro-sociological approach, characterized by the careful analysis of verbal and nonverbal interactions. Two research questions were raised: (1) How is social adaptation pursued in verbal and nonverbal interactions in preschool teacher–child relationships during a goal-oriented activity? and (2) How can social adaptation in the preschool context be understood in terms of a “deference-emotion system”? Interactions between a teacher and child in two video-recorded episodes were transcribed and sequentially analyzed thoroughly. The findings suggest that the interactions were regulated through an informal system of social sanctions, in which nonverbal signs of deference played a key role. The interaction was shown to be embedded in an institutional context that advocates goal-oriented instruction, thus highlighting the challenge of preschool teaching in attempting to promote goal-oriented processes while simultaneously maintaining respectful, caring teacher–child relationships.

In order to improve the safety of Li-ion batteries, solid-state electrolytes have been studied for many years. However, lithium is known to have lower diffusion coefficients in these materials. Various methods can be used to investigate lithium transport mechanisms; one of them relies on isotopic tracing. This method often used in environmental sciences, medicine and biology has been developed since 2011 by Lu et al. in the battery field. In addition to the techniques commonly used for isotopic analysis of lithium in battery materials, such as nuclear magnetic resonance (NMR) and mass spectrometry techniques, a new complementary method for determining the spatial distribution of the lithium isotopic ratio in solid electrolytes has been developed: laser induced self-reversal isotopic spectrometry (LIBRIS) proposed by Touchet et al. in 2020. In this paper, a proof of concept of LIBRIS analysis of a solid electrolyte composed of poly(ethylene oxide) (POE) containing 6Li enriched lithium bis(trifluoromethylsulphonyl)imide (LiTFSI) was first achieved. Then, the lateral resolution of LIBRIS measurements was improved from 250 μm down to 7 μm. Such lateral resolution is well adapted to future studies of lithium transport mechanisms in a solid electrolyte composed of a dispersion of ceramic microparticles in a polymer matrix. This material design is used as a trade-off to improve Li diffusion compared to polymer-based electrolytes. The sources of signal fluctuations were discussed, and a calibration curve of the 6Li isotopic abundance in POE/LiTFSI samples was finally obtained, with a relative uncertainty of 25%. The results demonstrate the feasibility of high resolution isotopic analysis by the LIBRIS technique and could be applied in the future to the characterization of the lithium mobility in battery materials. [Display omitted] • Isotopic tracing for the study of lithium mobility in solid battery electrolytes • LIBRIS measurements with 250 and 7 μm lateral resolution in Li 2 CO 3 and POE/LiTFSI • A 5–10% uncertainty on the 6Li isotopic abundance is reached with a 250 μm resolution • A 25–30% uncertainty on the 6Li isotopic abundance is reached with a 7 μm resolution • Opens the way to the analysis of particles/polymer interfaces in hybrid electrolytes [ABSTRACT FROM AUTHOR]

• The low concentrated ultra-fine tailings (LUFTs) were used as filling material for their resource utilization. • A novel cementitious material suitable for LUFTs was developed. • The strength origin mechanism of the novel cementitious materials was analyzed. High concentrated ultra-fine tailings have been cemented using various methods and used as the backfill material, whereas the suitable cementitious material formulations for the low concentrated ultra-fine tailings (LUFTs) with a solid content ≤ 55% have not been presented. For the purpose of utilizing the LUFTs in practice, this study presented a binder formulation for cementing the LUFTs; the cementitious material is alkali-sulfate-activated slag, and some amounts of ordinary Portland cement were added as a reinforcing agent to improve the properties of cemented LUFTs. The results showed that a binder with 61.3% GBFS, 20.0% cement, 15.1% anhydrite, and 0.5% alkaline activator (in which 50% for both quicklime and sodium metasilicate nine-hydrate), a binder to tailing ratio of 1:8, and a tailing slurry concentration of 55% exhibited the highest strengths in 3d, 7d and 28d, respectively 0.62 MPa, 0.93 MPa, and 1.41 MPa. Moreover, based on the XRD, TG, and SEM analysis, the compressive strength mainly originates from the reticular skeleton structure formed by the hydration product such as C-S-H gels and ettringite. [ABSTRACT FROM AUTHOR]

• Composite activation can effectively stimulate the activity of copper smelting slag (CSS). • The orthogonal experimental method was used to optimize the experimental ratio. • The microstructure and hydration mechanism were studied by XRD, SEM and EDS. • A new type of CSS based composite mine backfill cementitious material was developed. The stockpiling of copper smelting slag (CSS) has broken the ecological environment of the mining area, and the resource utilization of CSS is an urgent requirement to promote ecological sustainable development. The optimal cementitious material ratio determines as 69:15:6:2:8 for CSS: cement clinker (CC): gypsum powder (GP):NaOH: slaked lime (SL) by analyzing the physical and chemical properties of CSS and the uniaxial compressive strengths (UCS) at 3d, 7d and 28d curing ages investigate. The uniaxial compressive strengths reached 3.55 MPa, 9.48 MPa, and 32.43 MPa. In the meantime, XRF, XRD, EDS, and SEM microscopic analysis of the prepared gelling material specimens explored the hydration products and microstructural changes of the backfill gelling system and revealed the hydration mechanism of the gelling system and the strength formation mechanism of the specimens. The results of the experimental study showed that the strength of the specimens at different maintenance ages was subject to different significance arrangements of the factors. Based on the optimized ratio of composite cementitious materials, the 28d UCS of the filler prepared by synergistic tailing sand reaches 3.88 MPa, which can meet the jksg of partial mine filler mining. Applying copper smelting slag-based gelling backfill materials (CSSM) at mine sites reduces backfill costs while effectively reducing solid waste emissions, thereby protecting the environment and promoting the realization of waste-free mines and green mining. [ABSTRACT FROM AUTHOR]

• A double reactive ion etching process is used to integrate silicon nanowires. • SiO 2 /Al 2 O 3 all-around surrounding gate structure is realized. • Suspended N+/P/N+ SiO 2 /Al 2 O 3 silicon-nanowire-based devices are top-down integrated. • Excellent electrical and pH detection properties are evidenced at the microscale. A technological process was proposed in order to integrate fully silicon-nanowire-based field-effect nanodevices on a silicon-on-insulator (SOI) substrate. Thanks to a double reactive ion etching process of the SOI silicon upper layer as well as to a "SiO 2 thermal oxidation growth / Al 2 O 3 atomic layer deposition" gate process, silicon-nanowire-based field-effect transistors (SiNW-FET) and silicon-nanowire-based ion-sensitive field-effect transistors (SiNW-ISFET) were fabricated. Focuses were brought on (i) the integration of a suspended N+/P/N+ double-junction structure (gate length: ∼ 0.75 μm and ∼ 3.75 μm), (ii) the fabrication of a SiO 2 /Al 2 O 3 all-around surrounding gate structure, (iii) the achievement of low nanowire sections (width: ∼ 150 nm, height: ∼ 200 nm), and (iv) the final adaptation to the liquid phase analysis thanks to SU8-based wafer-level packaging. According to the proposed process, SiNW-FET and SiNW-ISFET devices showed excellent electrical characteristics in terms of leakage resistance R OFF , subthreshold current slope and I ON /I OFF maximal ratio. SiNW-ISFET devices were finally studied for the pH analysis at the submicronic scale (analysed volumes: ∼ 10 pL), evidencing standard potentiometric detection sensitivity (∼ 56 mV/pH), as well as excellent amperometric detection sensitivity (∼ 0.4 current decade per pH) in subthreshold regime. [Display omitted] [ABSTRACT FROM AUTHOR]

This work explored the correlation among the physical and mechanical parameters of concrete in marine environments during corrosion. Concrete materials with varied water–cement ratios (w/c) were soaked in four kinds of simulated seawater, including a compound solution of sodium chloride (NaCl) and magnesium sulfate (MgSO4), a solution of MgSO4, a solution of sodium sulfate (Na2SO4), and clear water. The macroscopic physical and mechanical parameters, such as compressive strength, tensile strength, mass change and ultrasonic wave velocity, were measured. The damage mechanism of corrosion products and microstructures was analyzed using microscopic approaches including scanning electron microscopy (SEM), X-ray diffraction (XRD), etc. Linear correlation was carried out on the abovementioned physical parameters, and the results revealed that, during corrosion, the correlation between compressive and tensile strength and mass (excluding Na2SO4 solution) is positive (mostly highly correlated), while that with wave velocity is poor (mostly moderately correlated). [ABSTRACT FROM AUTHOR]

• Ultra-fine tailing cementitious activity index increased from 0.49 to 0.71 by grinding. • Mine backfilling requirements were met with a slurry concentration of 78%. • The hydration products formed in the G3 sample greatly improved its strength. • C − S − H and C−(A)S − H gel augmentation increased less harmful pores from 17.4 to 66.4%. • Extended curing time (3 to 28 days) improved strength due to C − S − H and C−(A)S − H gels. This study explores the influence of mechanical activation on the cementitious activity of ultra-fine tailing and the filling performance and hydration mechanisms of a clinker-free backfilling body. A binder with 50% granulated blast furnace slag, 35% steel slag and 15% desulfurisation gypsum, a binder to tailing ratio of 1:4, and a slurry concentration of 78% resulted in strength values of 6.69 MPa, 12.05 MPa, 16.36 MPa and 18.37 MPa after 3, 7, 28 and 180 days, respectively. Ettringite formed during metallurgical slag hydration and C-(A)S-H gels formed by superfine tailings under alkali activation resulted in the high compressive strength. [ABSTRACT FROM AUTHOR]

The international trend of positioning the preschool as a pre-academic learning environment is challenging for preschool teachers, as it necessitates a balance between emotionally supportive interaction and goal-oriented learning instruction. However, previous research suggests that the complexities of such interactions need to be further studied. This article contributes by presenting a very detailed exploration of how social adaptation is pursued in a goal-oriented documentation activity. The study used a micro-sociological approach, characterized by the careful analysis of verbal and nonverbal interactions. Two research questions were raised: (1) How is social adaptation pursued in verbal and nonverbal interactions in preschool teacher–child relationships during a goal-oriented activity? and (2) How can social adaptation in the preschool context be understood in terms of a "deference-emotion system"? Interactions between a teacher and child in two video-recorded episodes were transcribed and sequentially analyzed thoroughly. The findings suggest that the interactions were regulated through an informal system of social sanctions, in which nonverbal signs of deference played a key role. The interaction was shown to be embedded in an institutional context that advocates goal-oriented instruction, thus highlighting the challenge of preschool teaching in attempting to promote goal-oriented processes while simultaneously maintaining respectful, caring teacher–child relationships. [ABSTRACT FROM AUTHOR]