Search

Alumina ceramic samples with complex structures were prepared using a self-made down-mounted surface exposure forming system with a scraping mechanism and a ceramic slurry with an oxygen polymerization effect. A high-solid-phase, low-viscosity alumina slurry (1.55 Pa s viscosity at a 30 s−1 shear rate at 55 vol%) was developed. The effects of exposure time and oxygen pressure on the curing thickness and contour accuracy before and after oxygen permeability were studied. Under the optimal oxygen pressure (0.4 kPa), oxygen generation could effectively reduce the error caused by the scattering of the ceramic powder, improve the contour accuracy of the inner hole, and reduce the size error of the inner hole by 7.2 % compared with the unoxygenated generation. According to the application requirements of aluminum-based ceramic parts, the corresponding degreasing and sintering curves were formulated, and the closed porosity of the ceramic (>40 μm) after sintering was 1.18 %, relative density was 69.3 %, apparent porosity was 29.3 %, and flexural strength was 41.53 MPa. This presents new potential technical avenues for the preparation of ceramic parts with complex structures. • A high-solid content low-viscosity slurry with excellent performance was obtained. • The profile error caused by the scattering of ceramic powder can be effectively reduced and the profile accuracy of the inner hole can be improved by using the oxygen inhibition effect. • The 3D printing products with good mechanical properties and high forming accuracy were prepared by using the self-developed printer. [ABSTRACT FROM AUTHOR]

Cementing technology is crucial to the development of oil and gas resources, and the quality of cement slurry required is an important factor affecting the cementing effect. Previous studies ignored mixing speed effect on cement slurry quality. CFD numerical model is established to simulate the flow filed of the agitated slurry tank under various operation and structural parameters. The multiphase flow model and the k-ε turbulence model are used to describe the turbulence characteristics in the agitated slurry tank. The multiple reference frame (MRF) model is used to realize the rotation of the area near the stirring blade. The results indicate that the density of the cement slurry in the agitated slurry tank can finally reach a stable state, and the concentration distribution is uniform. Increasing the rotational speed, the stirring time needed to achieve stability becomes shorter, and the uniformity of the cement slurry will also be improved. Reducing the distance between the impeller and the bottom of the agitated slurry tank, the mixing effect can be improved. It provides certain theoretical guidance for the practical application of this agitated slurry tank and has certain reference significance for research on improving the quality of cement slurry required for cementing. [ABSTRACT FROM AUTHOR]

The wear and corrosion issues commonly occurring in coal production and processing and applications of advanced ceramics and coatings to combat these issues are reviewed. The ceramics' and coatings' application areas encompass (i) solid (bulk) ceramic and composite components, specifically cyclones, lining and piping systems working in prolonged contacts with coal solid particles and concentrated coal-containing slurries, which move at high velocities and various trajectories through these systems, (ii) lining and accessories in coal-based materials' combustion and related heat treatment equipment, and (iii) piping systems, which should work in contact with high-temperature corrosive gas flows, often containing abrasive particulates, occurring through combustion processes. The comprehensive review demonstrates manufacturing of large components made of oxide and non-oxide ceramics (specifically SiC-based), ceramic-based composites and protective coatings on steel components, especially for long piping. Some of these materials and products, specifically, alumina-based ceramics and SiC-based ceramics and thermal diffusion and reaction-processed coatings, were developed and manufactured by the author and his team. Structure and properties of these materials, as well as their manufacturing features, affecting wear and corrosion resistance of components are discussed. The highly consolidated materials based on considered ceramic ingredients with microcrystalline structures or/and with larger reinforcing grains of selected sizes provide high wear and corrosion resistance, including for high temperature applications. The recorded data and proposed analysis may be also applicable for some other mineral and power generation processes and situations. [ABSTRACT FROM AUTHOR]

To enhance the ablation resistance of carbon-reinforced carbon aerogel (C/CA) composites, a SiC/ZrC–SiC coating was applied using slurry brushing and gaseous silicon infiltration techniques. The samples were exposed to an oxyacetylene flame at temperatures exceeding 2000 °C for 60 s, after which the peak front-side temperature of the coated C/CA was 288 °C lower than that of pure C/CA. The linear ablation rate of the coated C/CA (1.72 ± 0.08 μm/s) decreased by 89.7% compared to that of pure C/CA (16.4 ± 0.08 μm/s). The reduction in the front-side temperature was attributed to the high emissivity of the SiC coating and the evaporation of SiO 2 during ablation. Moreover, due to its low oxygen permeability, the dense SiO 2 –ZrO 2 layer prevented the inner coating and matrix from further oxidation. In addition, the introduction of phenolic resin nanoparticles within the C/CA matrix limited heat conduction, resulting in a peak back-side temperature of only 91 °C for the 10-mm-thick sample. [ABSTRACT FROM AUTHOR]

The study investigated the viability of 3D-printed zirconia specimens created using solvent-based ceramic slurry stereolithography (3S), focusing on their utility in dental ultra-thin laminate veneers. Solvent debinding was employed to minimize defect risks, with the debinding process designed based on thermogravimetric analysis. The study evaluated how solvent debinding affected the microstructural and mechanical properties of the zirconia specimens. Optical properties of 0.1 mm and 0.3 mm thick ultra-thin veneers were characterized, focusing on color parameters and relative translucency (RTP 00) values. Following solvent debinding, the green bodies exhibited noticeable surface pores, although this did not compromise density or dimensional accuracy. The sintered specimens treated with solvent debinding showed a slight increase in tetragonal phases, a significant reduction in surface roughness, and improvements in Vickers hardness and flexural strength. Cell viability tests confirmed more than 90% viability for NIH-3T3 cell lines, highlighting excellent biocompatibility. Veneers with a 0.1 mm thickness demonstrated RTP 00 values between 16.57 and 19.38, and the shade of the dental substrate notably influenced their color. The study demonstrated that the solvent debinding process effectively reduced porosity, consequently improving the mechanical properties of specimens fabricated using the 3S technique. Ultra-thin zirconia veneers produced by this method exhibited high RTP 00 values, indicating their potential suitability for anterior dental applications. Notably, the substrate shade emerged as a critical factor in achieving optimal aesthetic results. [ABSTRACT FROM AUTHOR]

In this paper we present the results of an investigation of the influence of excess energy applied through ball milling on surface hydration behavior of alumina particles manufactured by three different methods. It is shown that different hydration amount are generated due to the defects and newly generated surfaces introduced during high energy ball milling processes. And the various gibbsite/bayerite ratio of the formed hydrates are attributed to the coordination defects resulting from heat treatment during the manufacturing process. As a result, it is confirmed that the dispersant works more efficiently with particles in which hydrates are formed, and the surfaces with structures closer to gibbsite seem to respond more effectively to dispersant in slurries. [ABSTRACT FROM AUTHOR]

Vacuum preloading combined with prefabricated vertical drains is a widely used system for improving soft clay-dredged slurry deposits. However, the influence of the initial water content on clogging is not yet fully understood. In this study, laboratory model tests were conducted on slurry with initial water contents of 106%, 133%, and 159% during vacuum preloading. The process of vacuum preloading was monitored from the perspectives of discharged water volume, pore water pressure, as well as the displacement and strain profile of soil patches by using the novel particle image velocimetry (PIV) technique. The results showed that the clogging formation process could be divided into three stages based on the water discharge rate: rapid formation, transition, and slow formation. An increase in initial water content resulted in a larger horizontal displacement, leading to a thinner and denser clogging zone with lower permeability coefficients and a reduced rate of pore pressure dissipation. Empirical equations for the thickness of the clogging zone versus time were proposed using the PIV technique, providing a reference for theoretical consolidation calculations and making the calculations more practical by considering the variation of the clogging zone during vacuum preloading. [ABSTRACT FROM AUTHOR]

The traditional way of transporting iron ore from mine to end-use plants often causes the industry significant economic hardship and degradation of the ecological system. Hydrotransportation of slurry through a pipeline is a remarkably viable strategy for effectively transporting iron ore in terms of economics, dependability, and safety, with minimal environmental impact. In the present investigation, a blend of bimodal samples is prepared by mixing medium and coarse particles of Indian iron ore of size 38–75 (I-2) and 75–106 (I-3) µm, respectively, with finer particles of size <38 µm (I-1) in 10–40% (by weight) proportion. Rheological characterization of the blend samples is done to finalize the optimum particle size. To enhance the flowability and stability of the concentrated iron ore samples, they are amalgamated with a mixture of plant-based nonionic saponin extracted from Sapindus mukorossi (Ritha) and the anionic sodium dodecyl sulfate (SDS) surfactants. The correct proportion of SDS in saponin is obtained through a thorough analysis of critical micellar concentration, zeta potential, and rheological parameters. Finally, the stability and slurryability of iron ore suspension with a Saponin–SDS mixture are established through rheological properties, dispersant concentration, and stabilization mechanisms. It is found that the optimum proportion of a mixture of saponin–SDS significantly improved the slurryability and stability of iron ore suspension and the maximum iron ore loading was enhanced by up to 81% by weight. The head loss and specific energy consumption analysis successfully evidence the significance of the surfactants in transporting the slurry through pipelines. [ABSTRACT FROM AUTHOR]

The compressive and shear bond strengths between the masonry units are the most important factors in determining the overall strength of an infill wall. The compressive and shear bond strength of autoclaved aerated concrete (AAC) or autoclaved cellular concrete (ACC) is heavily influenced by its porosity, density and moisture content. Because ACC has more porosity and water absorption than standard clay brick, customers and designers of ACC are sometimes worried about the formation of cracks at high water contents. As a result, an experimental study was conducted to analyze the compressive and shear behavior of ACC brick units, cement mortar, and masonry with reference to three diverse moisture conditions (1) oven-dried, (2) air-dried, and (3) wet conditions. In this investigation, three distinct mortar mixes were considered, each characterized by cement-to-sand ratios of 1∶2 , 1∶4 , and 1∶6. Prior to setting the cement sand mortar in the brickwork, a thin layer of cement slurry was applied to the block surface. The compressive behavior of ACC masonry was assessed using masonry prism specimens made of four layers of bricks and three mortar joints, whereas the shear bond strength of ACC was assessed using masonry triplets made of three layers of brick and two mortar joints. Throughout the study, the mortar thickness of 10–15 mm was maintained. The average of two prism and triplet specimens was used for all the masonry compressive strength and shear bond strength data reported in this investigation. The experimental results indicate that moisture content has a substantial impact on the compressive and shear bond strengths of ACC. Increasing moisture content will significantly decrease the compressive strength of ACC brick units, cement mortars, masonry prisms, and shear bond strength of masonry triplets. For a wet masonry prism, mortar with designations 1∶2 , 1∶4 , and 1∶6 had average strength reductions of 49.74%, 54.97%, and 59.85%. The average strength drops for mortar with 1∶2 , 1∶4 , and 1∶6 ratios in wet masonry triplets was 44.3%, 61.1%, and 62.5%, respectively. [ABSTRACT FROM AUTHOR]

To study the reinforcement mechanism of expansive slurry from a mesoscopic perspective, shear simulation tests were conducted on a slurry–fractured rock mass composite using PFC2D (version 5.00.35). The tests analyzed the distribution of cracks, the process of damage evolution, the distribution characteristics of intergranular contact forces, and the displacement of particles. The results indicate that (1) the volume expansion of the expansive slurry compressed the rock mass, causing the slurry particles to penetrate the pores of the rock particles. This process increased the contact area between the slurry and the rock mass, improved the friction, and intensified the degree of interlocking between the slurry and the rock mass, thus improving the bonding between them. (2) Both composite rock masses exhibited similar macroscopic damage patterns consistent with the laboratory tests. During shear tests, both composites experienced four stages of crack development: crack initiation, slow crack development, rapid crack development, and stable crack number. (3) The expansion stress, along with its reaction force and friction force, increased the integrity of the composite rock mass, reducing the differences in particle displacement direction and velocity. This led to improved internal deformation coordination within the composite rock mass, resulting in fewer cracks during shear tests. [ABSTRACT FROM AUTHOR]

In the current investigation, a cold sprayed WC-12Co (WC- Tungsten Carbide, Co- Cobalt) composite coating was deposited on CA6NM steel. Further, microstructural analysis was carried out by using Scanning Electron Microscopy (SEM)/Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD) characterization techniques. Mechanical characterization was carried out to measure microhardness, bond strength and surface roughness. The value of coating hardness and surface roughness was measured to be 270 ± 15 Hv and 2.12 ± 0.5 μ m. Thereafter, slurry erosion test was performed under accelerated conditions and performance of coated samples was compared under different parameters such as erodent size, impact velocity, angle of impingement and slurry concentration. WC-12Co coatings show no phase transformation or de-carburization of the WC-Co particles as observed in other thermal spray techniques. The WC-12Co coatings was proved to have beneficial erosion reduction rate as compared to untreated CA6NM steel. The slurry erosion performance of coated samples was improved by 68%. SEM images of degraded coatings show the brittle characteristic of WC-12Co coatings. [ABSTRACT FROM AUTHOR]

[Display omitted] Processing of electrode slurry, which is highly non-Newtonian fluid, is a critical step in the mass production of lithium-ion batteries (LIBs). While extensional flow plays an important role in the electrode slurry processes such as coating, most previous studies have focused only on the shear rheology, due to the lack of a reliable method to measure the extensional rheological properties of the slurry. Here, it is demonstrated that the extensional rheological properties of the anode slurries can be successfully characterized using the stop-flow-dripping-onto-substrate/capillary break-up rheometry (SF-DoS/CaBER). Using this system, it is observed that the extensional rheology of the anode slurry is significantly affected by the blend ratio of the natural and synthetic graphite, as well as the binder and conductive concentrations. Furthermore, the shear rheology-based model predicts much shorter pinch-off times than those measured experimentally, indicating that the yield-stress of the anode slurry is much larger in extensional flow than in shear flow. [ABSTRACT FROM AUTHOR]

Cracks generated in sheet coating of water-based slurries are an increasingly important concern in the development of diverse material science, such as fine ceramics, Pt catalysts, and Li transition metal oxides, from an environmental safety perspective. However, a comprehensive understanding of crack formation remains elusive due to the intricately entangled interplay among various characteristics of slurries. Here, we systematically ascertain the causes at work in crack initiation by analyzing the physical parameters of a series of aqueous alumina slurries using machine learning. The analysis reveals a strong correlation between rheological hysteresis and sheet cracking. As a verification of the correlation, the crack suppression by controlling the rheological hysteresis is experimentally confirmed. Furthermore, we visualize the microstructure in the slurry that induces cracks with a liquid-phase scanning electron microscope, clarifying the rheological dynamics. These results disentangle that rheological hysteresis is a good indicator directly reflecting microstructural durability against drying stress. [Display omitted] [ABSTRACT FROM AUTHOR]

Anchor and fissure grouting are used to repair earthen sites. However, the common method to obtain the compressive strength of grouting slurry would cause material, labor, and time losses. In addition the material properties, environmental and economic benefits have gained increasing attention. This study proposes a design framework for multi-objective proportioning optimization based on machine learning and metaheuristics. The results indicated that the eXtreme Gradient Boosting (XGBoost) model, whose hyper-parameters were optimized by a genetic algorithm, can accurately predicted the compressive strength of the slurries. The impact of the variables on development of compressive strength can explain the internal reaction mechanisms. The analytical framework based on meta-heuristic and technique for order of preference by similarity to an ideal solution (TOPSIS) provided Pareto-optimal solutions in design scenario of each sub-dataset. The framework proposed in this study can efficiently achieve mechanical, environmental, and economic design objectives of anchor grouting and fissure grouting slurries for repairing earthen sites. [ABSTRACT FROM AUTHOR]

In order to strengthen the safety management of coal slurry preparation systems, a dynamic risk assessment method was established by using the bow-tie (BT) model and the Structure-variable Dynamic Bayesian Network (SVDBN). First, the BT model was transformed into a static Bayesian network (BN) model of the failure of a coal slurry preparation system by using the bow-tie model and the structural similarity of the Bayesian cognitive science, based on the SVDBN recursive reasoning algorithm. The risk factors of the coal slurry preparation system were deduced using the Python language in two ways, and at the same time, preventive measures were put forward according to the weak links. In order to verify the accuracy and feasibility of this method, the simulation results were compared with those obtained using GeNIe software. The reasoning results of the two methods were very similar. Without considering maintenance factors, the failure rate of the coal slurry preparation system gradually increases with increasing time. When considering maintenance factors, the reliability of the coal slurry preparation system will gradually be maintained at a certain threshold, and the maintenance factors will increase the reliability of the system. The proposed method can provide a theoretical basis for the risk assessment and safety management of coal slurry preparation systems. [ABSTRACT FROM AUTHOR]

Working fluids that incorporate solid microencapsulated phase change materials (MPCMs) can benefit from properties such as density and viscosity, which are crucial for improving heat capacity and transfer. However, limited data are available on these parameters for specific slurry and mass ratios. In this study, we present a comparative analysis of the experimental results on the viscosity of three different MPCM aqueous dispersions, namely MPCM 31-S50, MPCM 25-S50, and Micronal 5428X. Varying MPCM mass ratios of distilled water were used to obtain different mass concentrations of the phase change material (PCM), and the resulting slurries were analysed at temperatures ranging from 15 to 40 °C. Our findings showed that all slurries exhibited non-Newtonian characteristics at low shear rates, with viscosity stabilising at higher shear rates, resulting in the characteristics of a Newtonian fluid. The viscosity results were highly dependent on the type of MPCM base dispersion, particularly at high mass ratios, with the slurries having viscosities higher than those of water. Furthermore, we conducted density experiments as a function of temperature, using a flow test setup and a Coriolis flowmeter (Endress+Hauser, Reinach, Switzerland) to determine the density of two MPCMs, namely MPCM 25-S50 and Micronal 5428X. The test samples were prepared at mass concentrations of 10%, 15%, and 20% of the phase change material. We found significant differences in density and viscosity for different MPCM slurries as a result of both the PCM concentration and the material studied. Our results also revealed an apparent PCM phase change process, in which the slurry density significantly decreased in the temperature range of the phase transition from solid to liquid. [ABSTRACT FROM AUTHOR]

Ceramisite lightweight concrete has excellent performance and relatively light self-weight characteristics. At the same time, the recent development of green high-performance concrete and prefabricated components has also brought the abundant utilization of these mineral mixture. An interfacial transition zone exists between the hardened cement paste and the aggregate, which is the weakest part of the concrete, characterized by high porosity and low strength. In order to study the effect of slag content on the interfacial transition zone in lightweight high-strength concrete, experiments were designed to replace cement with slag at different contents (0%, 5%, 10%, 15%). A series of studies was conducted on its macro-strength, microstructure, and composition. The results indicated that the addition of slag improved the porosity and width of the interfacial transition zone. Adding slag did not reduce the thickness of the concrete interfacial transition zone significantly at 3 d, but it led to significant improvement in the thickness of the interfacial transition zone at 28 d, and the thickness of the interfacial zone at 28 d was reduced from 19 μm to 8.5 μm, a reduction of 55%. The minimum value of microhardness in the slurry region of the interfacial specimens also increased from 19 MPa to 26 MPa, an increase of 36%. In addition, the structural density of the interfacial region was further increased, resulting in varying degrees of improvement in the macroscopic anti-splitting strength. One of the important reasons for this phenomenon is that the addition of slag optimizes the chemical composition of the interface and promotes the continuation of the pozzolanic reactivity, which further enhances the hydration at the interface edge. [ABSTRACT FROM AUTHOR]

The production of flue gas desulfurization gypsum poses a serious threat to the environment. Thus, utilizing gypsum-based self-leveling mortar (GSLM) stands out as a promising and effective approach to address the issue. β-hemihydrate gypsum, cement, polycarboxylate superplasticizer, hydroxypropyl methyl cellulose ether (HPMC), retarder, and defoamer were used to prepare GSLM. The impact of mineral admixtures (steel slag (SS), silica fume (SF), and fly ash (FA)) on the physical, mechanical, and microstructural properties of GSLM was examined through hydration heat, X-ray diffractometry (XRD), Raman spectroscopy, and scanning electron microscopy (SEM) analyses. The GSLM benchmark mix ratio was determined as follows: 94% of desulfurization building gypsum, 6% of cement, 0.638% each of water reducer and retarder, 0.085% each of HPMC and defoamer (calculated additive ratio relative to gypsum), and 0.54 water-to-cement ratio. Although the initial fluidity decreased in the GSLM slurry with silica fume, there was minimal change in 30 min fluidity. Notably, at an SS content of 16%, the GSLM exhibited optimal flexural strength (6.6 MPa) and compressive strength (20.4 MPa). Hydration heat, XRD, and Raman analyses revealed that a small portion of SS actively participated in the hydration reaction, while the remaining SS served as a filler. [ABSTRACT FROM AUTHOR]

The flowability and mechanical properties are increasingly crucial in the filling process of deep metal mines with mining depths exceeding 1000 m. The rheological properties of filling slurry in the pipeline were analyzed through rheological tests, L-tube self-flow tests, and semi-industrial loop tests. The results revealed that with an increase in the cement-to-tailings mass ratio (c/t ratio) and mass concentration, the slurry exhibited a higher flow resistance and decreased stowing gradient. During slurry transportation, the pressure loss in the straight pipe was positively correlated with the slurry flow rate, c/t ratio, and mass concentration. A uniaxial compressive strength (UCS) test was conducted to analyze the mechanical properties of the cemented paste backfill containing BMC (CCPB) in both standard and deep-underground curing environments. The UCS of the CCPB showed an increasing trend with the rise in curing age, mass concentration, and the c/t ratio. The comprehensive analysis concluded that when the c/t ratio is 1:4, and the mass concentration is approximately 74%, and parameters such as the slump, bleeding rate, and flowability of the filling slurry meet the criteria for conveying and goaf filling, resulting in a high-strength filling body. [ABSTRACT FROM AUTHOR]

AbstractThe design of a mineral slurry transportation system is difficult because of the non-Newtonian nature of the flow at high slurry concentrations. The behavior of the slurry depends on many physio-chemical properties such as particle density, particle size distribution (PSD), particle shape, chemical composition, pH etc. This work presents a comparative study between three preferred methods of scale-up of the head loss in larger diameter pipelines, namely Bowen’s Method, rheological method and Wilson’s Method. The performance of each method is validated with the pipe loop test data in a 200 DN pipeline. A high concentration (>50% by weight) iron ore concentrate slurry was used for carrying out the above study. This work would be beneficial for engineers involved in the design and maintenance of the slurry pipelines with respect to the choice of the scale-up methods available for estimation of the head loss for a time independent, homogenous, non-Newtonian particulate slurry for both laminar and turbulent regime. [ABSTRACT FROM AUTHOR]

This study examined the effects of starting material dispersion on the formation of AlN powder synthesized by carbothermal reduction-nitridation (CRN) route. After preparing aqueous and non-aqueous slurries containing 6.5 vol % of Al 2 O 3 and carbon black powder with/without a dispersant, the particle dispersion was evaluated by sedimentation and viscosity measurements. The zeta potential was also measured to determine the optimal dispersion conditions for electrostatic repulsion because carbon black is challenging to disperse in water, owing to its low surface charge and poor wettability. The aqueous slurry prepared with 5 wt % Gen0451 dispersant at pH = 10 showed the highest degree of dispersion. Complete AlN conversion was achieved by nitridation at 1600 °C for 6 h under 10 L/min N 2 flow. This result clearly showed the importance of starting material dispersion on the synthesis of AlN by CRN, demonstrating the feasibility of aqueous processing instead of conventional solvent-based processing. [ABSTRACT FROM AUTHOR]

Silica sol can activate the surface of hollow ceramic microspheres and improve the properties of composite materials by improving the interface between the microspheres and the epoxy resin. The group changes on the surface of microspheres were measured using infrared spectroscopy. The microspheres were observed with a scanning electron microscope. The density, water absorption, and mechanical properties of the materials were tested using scales and mechanical testing machines. The results showed that SiO2 and silane molecules were introduced on the surface of the microspheres after treatments. As the silica sol content increased, the slurry viscosity increased by 34.5%, the composite density increased by 5.8%, and the water absorption decreased by 35.8%. When the silica sol content was 25%, the flexural strength and compressive strength of the composites were 73.49 and 116.27 MPa, respectively, which were 37.8% and 23.6% higher than those of the untreated composites, and the mechanical properties became clearly improved. High mechanical properties enable the materials to be used in deeper ocean areas. Highlights: Nanoparticles are introduced onto the surface of hollow microspheres.The activated microspheres can bind better to the silane coupling agent.Silane coupling agent assisted by silica sol improved interfacial bonding.Surface activation of microspheres improves the properties of composites. [ABSTRACT FROM AUTHOR]

Osteogenic differentiation and bone regeneration can be effectively aided by porous scaffolds with multiscale cellular structures, making it easier to repair defects in bone tissue. Due to the scarcity of pore-forming agents, it is extremely challenging to fabricate interconnected hierarchically porous zirconia at multi-scale. This work described a novel and straightforward method for directly imprinting a slurry containing two pore-forming agents (microspherical and filamentary) to produce strong and highly porous zirconia (ZrO 2) ceramics with four levels of porosity ranging from nanometers to millimeters. The concentration of hemp fibers significantly affected printability when the rheological behavior of a zirconia slurry was examined. Utilizing a scanning electron microscope (SEM) to monitor the development of powder interstices under various sintering techniques. The permeability performance was assessed when simulated plasma had fully filled the scaffolds. The structure had a high compressive strength of 24.18 MPa, a porosity of 80.9 %, an apparent porosity of 55.7 %, and took just 1.11 s to fill a scaffold that was 15 mm high. It is anticipated that the proposed route will be expanded to include various engineering materials for structural and practical applications. [ABSTRACT FROM AUTHOR]

Si 3 N 4 ceramics pose a challenge when it comes to the preparation of light-curing pastes with high depth of cure, elevated solid content, and low viscosity. This challenge is primarily attributed to their inherent characteristics, including high absorbance, a high refractive index, and suboptimal sphericity. Consequently, the application of Si 3 N 4 ceramics in 3D printing remains a complex endeavor. To address the intricacies associated with 3D printing using Si 3 N 4 ceramics, our research focuses on the utilization of Tetramethylammonium Hydroxide (TMAH) for pH adjustment in Si 3 N 4 ceramics. This adjustment aims to enhance the stability, curing depth, and viscosity of the slurry. Subsequently, we employ this Si 3 N 4 light-curing slurry for 3D printing, followed by sintering the printed materials. The evaluation includes testing for porosity, density, and flexural strength of the samples. Notably, our efforts yield porous silicon nitride ceramics boasting an impressive density of 1.8299 g/cm3, porosity measuring 43.718%, and remarkable flexural strength amounting to 275 MPa. [ABSTRACT FROM AUTHOR]

In the tunneling driven by large diameter slurry shield (SS), the working face is at risk of passive failure when the overburden is insufficient or the support pressure is excessive. This paper examines the partial progressive failure of the tunnel face by developing a hybrid mechanism which incorporates the failure zone into the complex movement. The failure blocks include a translational and a rotational one, and a spatial discretization technique is used to construct the velocity discontinuity between the blocks to ensure compatibility. To identify the failure extent of the face, the incipient failure origination is introduced. A kinematic approach is utilized to determine the upper bound solution for support pressure. By optimizing, the minimum support pressure is searched and the failure mechanism is gained in response. Additionally, this study performs the parametric analysis to discuss the influences of the factors such as frictional angle, cohesion, overburden depth, ground surface surcharge, and slurry weight on incipient failure origination as well as support pressure. The numerical analysis included in the framework of finite element limit analysis is carried out for verification. This paper ends with the validation of the current solution by re-examining the previous case. [ABSTRACT FROM AUTHOR]

Construction waste slurry is used as backfill in construction engineering as a type of solid waste. However, the initial water content of the waste slurry is high and must be dewatered beforehand to realize its resource utilization. This study proposes a staged vacuum preloading (VP) method with prefabricated horizontal drain (PHD)-prefabricated vertical drain (PVD) to treat waste slurry considering the advantages of VP with PHD in waste slurry disposal. The effect of different vacuum loading modes on PHD-PVD on waste slurry treatment is analyzed through four groups of large-scale experimental model tests. The test results indicate that the staged VP with PHD-PVD can effectively alleviate the clogging compared to the effect of synchronous VP with PHD-PVD, and the effect of the soil drainage consolidation is improved. The apparent clogging is alleviated by the gradually increasing vacuum pressure applied to PHD and PVD, when combined with the results of the microstructure analysis. These findings can provide design criteria for waste slurry disposal in similar applications. [ABSTRACT FROM AUTHOR]

Acidification of slurry is a promising approach for reducing ammonia emissions during the application procedure. Since only a few studies have been conducted focusing on ammonia emissions during the application of liquid organic fertilizers on the soil surface, a suitable incubation system was developed to evaluate the effects of acidification under controlled conditions. This incubation system was used to measure the ammonia emissions of various liquid organic fertilizers. The substrates were acidified with sulfuric and citric acid to different pH values to determine both the influence of the pH value of the substrates and of the type of acid on the ammonia emissions. The emissions decreased with declining pH value, and the reduction in emissions compared to the initial pH of the substrate was over 86% for pH 6.5 and over 98% for pH 6.0 and below. At the same pH value, the ammonia emissions did not differ between substrates acidified with citric acid and sulfuric acid, although more than twice as much 50% citric acid was required compared to 96% sulfuric acid to achieve the same pH value. Overall, our results demonstrate that the incubation system used is suitable for measuring ammonia emissions from surface-applied liquid organic fertilizers. The system allows for the differentiation of emission levels at various pH levels and is therefore suitable for testing the effectiveness of additives for reducing ammonia emissions from liquid organic fertilizers. [ABSTRACT FROM AUTHOR]

Coal gangue, the primary solid waste generated during the coal mining process, is typically disposed of on the surface, where it gradually accumulates to form gangue piles that significantly contaminate the surrounding environment. Filling technology has been widely employed for the safe and efficient disposal of coal gangue due to its sustainability, safety, and efficiency. However, there is still a lack of theoretical research on the concentration of gangue slurry in long-distance filling pipeline transportation. Therefore, a calculation model of the ultra-long-distance transportable concentration of coal gangue slurry with different grades was constructed based on the static anti-segregation performance and Bingham model. In addition, the relevant parameters of the calculation model of the ultra-long-distance transportable concentration of coal gangue slurry in this mine were determined using the 8 km pipeline transport of coal gangue slurry in one mine as the technical background. It was subsequently demonstrated that the yield stress, plastic viscosity, and mass concentration of the various grades of gangue slurry in this mine exhibit an increasing exponential function, while the slurry density and mass concentration exhibit an increasing linear function, and the mass concentration and actual flow rate correspond to a quadratic polynomial increment. Finally, the minimum and maximum concentrations for different grades of gangue slurry that can be transported over long distances in this mine were determined. This work provides theoretical and practical guidance on how to select the concentration of gangue slurry for long-distance pipeline transport. [ABSTRACT FROM AUTHOR]

A molecular dynamics-based model of semi-solid formation from liquid melt of the novel Al–15Mg2Si–4.5Si composite is reported in the present study. Growth kinetics of Mg2Si phase is studied here at the pre-nucleation stage i.e., prior to the emergence of a stable nucleus. Moreover, insight has been grabbed on semi-solid processing of the said composite at atomic level, wherein the dynamic evolution of the Mg–Si clusters has been studied during cooling/semi solid slurry generation as well as during isothermal holding stage. The effect of variation of cooling rate on the number of clusters, average size of clusters and density of clusters has been investigated. The average size of clusters decays exponentially with cooling rate, whereas the average atomic density of clusters decays following a power-law relation with cooling rate. The change of the thermodynamic parameters (enthalpy and potential energy) during the phase transformation from liquid to semi-solid state are determined here, which are then employed to determine the value of interfacial free energy of Mg2Si-melt interface in the Al–15Mg2Si–4.5Si composite, along with the parameters obtained from the dynamic evolution of Mg-Si clusters. The paper also reports the temporal evolution of solid content within the melt, corresponding to the Mg2Si phase, during slurry generation as well as during isothermal holding stage. [ABSTRACT FROM AUTHOR]

The pipeline transportation of iron ore slurry (IOS) is an eco-friendly alternate mode to transport the raw materials to longer distance and reduce the transportation network congestion problems. Proper selection of surfactant could modify mineral's viscosity, dispersion and wetting characteristics effectively as may be desired, which may further be monitored. A surfactant alters surface characteristics after being adsorbed onto minerals by altering the interfacial behaviour. This work is first report of the influence of a biosurfactant sourced from Aloe barbadensis Miller on the rheological behaviour of a high-grade iron ore (IO) sample at 45--72% by mass slurry concentrations range. The observed rheological parameters confirmed the non-Newtonian flow behaviour of the slurry. The collected IO and dried IOS samples were subjected to UV-Vis, XRF, PSD, XRD, SEM and EDS analyses. Experimental rheological data at varying concentrations was tested on various models to ascertain the best-fit rheological model for IOS transport. The Bingham model was found to be the most suitable to model the rheology of IOS. Experimental rheological behaviour of IOS was found to be linear with the yield stress. The study shall help to ascertain the suitability of a biosurfactant to stabilise high grade iron ores for pipeline transportation. [ABSTRACT FROM AUTHOR]

Bench tests were conducted on ore slurry filtration using the leaf test method, varying scales, pressures, and water/solids ratios. These results were compared with analytical outcomes derived from applying the dimensionless Buckingham pi method to the general equation of slurry filtration with incompressible cakes under constant pressure. The aim was to validate the tests by corroborating experimental findings with calculated parameters for scale-up purposes. Vacuum pressure was employed to facilitate slurry dewatering, forming a cake comprising solids from the slurry. This cake's thickness evolved over time, introducing specific resistivity that impeded filtering efficiency. Parameters such as cake resistance and filter media resistance were computed. Filtrate volume was measured over time to determine the filtration rate. These values were then adjusted using factors obtained through dimensional analysis. These factors facilitated comparisons to validate the feasibility of employing the Buckingham pi method for predicting slurry filtration results at larger scales. The results indicated lower errors when analyzing the filtrate rate over time with a solids/water ratio of 20/80%. When evaluating cake resistance, the method yielded lower errors at a ratio of 70/30%, while results for medium resistance were inconclusive. It's important to consider the ratio and associated errors when predicting the behavior of an industrial filter based on bench test results, aiming to achieve theoretical scaled filtration rates and cake resistances. However, it's not advisable to rely on the Buckingham pi method for scale-up purposes when evaluating medium resistance. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Fang et al. Study on Dispersion, Adsorption, and Hydration Effects of Polycarboxylate Superplasticizers with Different Side Chain Structures in Reference Cement and Belite Cement." The correction addresses minor mistakes in Tables 1, 3, 6, and 8, as well as Figures 5, 7a, and 13. The authors acknowledge their negligence and provide the corrected versions of the tables and figures. The corrections have been approved by the Academic Editor, and the original publication has been updated. [Extracted from the article]

CeO2 is widely used in the field of chemical–mechanical polishing for integrated circuits. Morphology, particle size, crystallinity, and Ce3+ concentration are crucial factors that affect polishing performance. In this study, we successfully synthesized two novel triangular CeO2 abrasives with similar particle sizes (600 nm) but different morphologies and Ce3+ concentrations using a microwave-assisted hydrothermal method with high-concentration raw materials, and no surfactants or template agents were added. It is generally believed that CeO2 with a higher Ce3+ concentration leads to better polishing performance. However, the results of polishing indicate that CeO2 synthesized at 200 °C, despite its lower Ce3+ concentration, demonstrates outstanding polishing performance, achieving a polishing rate of 324 nm/min, and the Sa of Si wafers decreased by 3.6% after polishing. This suggests that, under similar particle size conditions, the morphology of CeO2 plays a dominant role in the mechanical effects during the polishing process. Additionally, compared to commercial polishing slurries, the synthesized samples demonstrated better polishing performance. This indicates that, in CMP, the pursuit of smaller spherical abrasives may not be necessary. Instead, the appropriate shape and particle size can better balance the material removal rate and surface roughness. [ABSTRACT FROM AUTHOR]

In order to address the issue of hole collapse, which frequently arises when boring piles are being constructed in intricate marine strata, this paper discusses the influence of the slurry ratio on the slurry performance as well as the mechanism of slurry wall protection. It performs this by means of theoretical analysis, laboratory ratio testing, engineering analogies, numerical simulation, and field testing. Our findings demonstrate that adding sodium polyacrylate and sodium carboxymethyl cellulose can enhance mud's viscosity, contribute to flocculation, and improve the connection between mud and soil layers. Refering similar engineering cases, three optimization schemes are proposed for achieving a mud ratio that offers wall protection in complex marine strata. Furthermore, the particle flow model of slurry viscous fluid is established. The collapse of holes in the sand layer is reflected in the uneven radial displacement of hole walls and the invasion of mud particles. Increasing the viscosity of mud gradually transforms the uneven radial deformation of pore walls in the sand layer into a uniform radial deformation, whereas increasing the proportion of mud significantly decreases the radial displacement of hole walls. Additionally, when the mud pressure in the hole is 300 kPa and 600 kPa, the wall protection effect is better, and there is no particle penetration by substances such as sand. It is found that a high mud pressure can promote the diffusion of mud particles into the sand layer, while low mud pressure cannot balance the pressure on deep soil. The results of the field tests show that the ratio of water–clay–bentonite–CMC-Na–sodium carbonate = 700:110:90:1.5:0.5 used (where the mass percentage of each material is 77.8% water, 12.2% clay, 10% bentonite, 0.16% CMC-Na, and 0.05% sodium carbonate) can effectively prevent hole collapse and reduce the thickness of the sand layer at the bottom of the hole by 50%. [ABSTRACT FROM AUTHOR]

Ultrasonic treatment has been widely used in the mineral flotation process due to its advantages in terms of operational simplicity, no secondary pollutant formation, and safety. Currently, many studies have reported the effect of ultrasonic treatment on mineral flotation and shown excellent flotation performance. In this review, the ultrasonic mechanisms are classified into three types: the transient cavitation effect, stable cavitation effect, and acoustic radiation force effect. The effect of the main ultrasonic parameters, including ultrasonic power and ultrasonic frequency, on mineral flotation are discussed. This review highlights the uses of the application of ultrasonic treatment in minerals (such as the cleaning effect, ultrasonic corrosion, and desulfuration), flotation agents (such as dispersion and emulsification and change in properties and microstructure of pharmaceutical solution), and slurry (such formation of microbubbles and coalescence). Additionally, this review discusses the challenges and prospects of using ultrasonic approaches for mineral flotation. The findings demonstrate that the application of the ultrasonic effect yields diverse impacts on flotation, thereby enabling the regulation of flotation behavior through various treatment methods to enhance flotation indices and achieve the desired objectives. [ABSTRACT FROM AUTHOR]

Polycrystalline metal‐organic framework (MOF) membrane films prepared on ceramic supports can separate gases with high energy efficiency. They generally exhibit very high permeance and selectivity but suffer from cost issues through the required ceramic supports. Increasing the area and reducing the ceramic component to a minimum can be a strategy to enabling neat membranes of MOFs. In a rapid prototyping approach using 3D‐printed porous scaffolds with a double‐helical channel geometry, an increased active membrane area‐to‐volume ratio is shown. Following stereolithographic printing and debinding of a ceramic slurry, an adapted sintering protocol is employed to sinter commercially available alumina slurries into porous scaffolds. The 3D‐printed scaffolds are optimized at a porosity of 40%, with satisfying mechanical stability. Furthermore, synthetic procedures yielding omnidirectional, homogeneous coatings on the outside and inside of the tubular scaffolds are developed. Membrane films of zeolitic imidazolate framework 8 and Hong Kong University of Science and Technology 1 covering a huge 50 cm2 membrane area are produced in this way by applying a counter‐diffusion methodology. Gas‐separation performance is evaluated for H2, CO2, N2, and CH4, in single‐gas measurements and on their binary‐gas mixtures. [ABSTRACT FROM AUTHOR]

Over the past 15 years, there have been numerous fatalities related to working with animal slurry. Working with cattle slurry releases toxic gases, in particular, hydrogen sulphide (H2S), which can cause acute central nervous system toxicity, breathing difficulties, and death if exposed to high concentrations. Real-time measurements of H2S gas were taken over distance and time, during the stirring of cattle slurry on farms. Gas was measured at eight slurry stores with differing typical configurations of indoor or outdoor stores and with or without slatted flooring. Highest H2S gas levels were measured from indoor stores under slatted floors, and generally at positions closest to the stirrer or the point of maximum stirring, with levels decreasing with distance from source. Most of the data indicate H2S gas levels increase very rapidly after stirring starts, and mostly decline to baseline levels within 30 min post start of stirring. There were, however, circumstances where gas levels remained high and only started to decline once the stirrer had stopped. H2S gas levels at all farms, at all positions measured were consistently below 10 ppm within 30 min of the stirrer being stopped. The current data highlight areas of the farm and ways of working that have the potential for workers and others to be at risk of exposure to toxic slurry gases. The area should be left to ventilate naturally for at least 30 min after the stirrer has been stopped before re-entering buildings. Influencing the design of stirring equipment and future slurry stores would likely reduce the risk of worker exposure to slurry gases. [ABSTRACT FROM AUTHOR]

The reduction in friction is a desired property in many industries. Some of the applications include the movement of liquid or slurry through a pipeline in oil or mining, the grinding of one metal on another during fabrication, metal on paper in the making of nearly any paper product, to even something closer to home with the movement of a brush or comb through one's hair. Friction yields higher degrees of strain or stress on one or both of the substrates. This can be costly due to energy requirements, wear of equipment, or even breakage of the substrate. Even though the need exists in so many industries, the mechanisms of lubricity vary enough in each that there really is not a universal lubricity aid that can successfully be applied across the different industries. A family of novel lubricity aids based on alkyl polyglucosides have been synthesized and evaluated in the lab on both metal/metal friction reduction as well as comb/hair friction reduction. One of the modified alkyl polyglucosides has yielded excellent reduction in friction in both applications. [ABSTRACT FROM AUTHOR]

Bentonite slurry is frequently used to temporarily stabilize the excavation for slurry tunnel boring machines (TBMs) driving in permeable soils, such as sand and gravel. In this study, two types of bentonite slurries (BS1 and BS2) were subjected to a series of infiltration column tests and modified fluid-loss tests under various pressure levels. Monitoring of water discharge and pore pressures at different depths of the sand bed enabled the identification of two effective sealing patterns during infiltration: the formation of a filter cake and rheological blocking. BS1 exhibited a tendency to form a filter cake, which played a vital role in effectively transferring the applied pressure to the underlying soil skeleton. The application of higher pressure facilitated the rapid formation of a filter cake, resulting in a shorter time span for slurry invasion and minimizing fluid loss. On the other hand, rheological blocking was dominant when using BS2, and the maximum infiltration distance was found to linearly increase with the applied pressure. A comparison between the measurement and a simple prediction model derived from Darcy's law revealed an overestimation of the infiltration distance during slurry invasion. Furthermore, based on the modified fluid-loss test, higher pressure was found to densify the filter cake and result in lower hydraulic conductivity. [ABSTRACT FROM AUTHOR]

When earth pressure balance tunnel boring machines (EPB-TBMs) tunnelling in abrasive sandy ground, soil additives are critical for promoting excavation surface stability, reducing residual soil permeability, decreasing screw conveyor torque, avoiding mud cake siltation and preventing excessive tool wear. However, the existing studies mainly focus on the first four aspects. The influence mechanism of soil additives on cutting tool wear is still unclear due to the lack of reliable test methods. In the present study, a newly developed WHU-SAT tester (Soil Abrasion Tester developed by Wuhan University) was used to evaluate the influence of conditioning additives (foam additives and bentonite slurry) on soil abrasivity. Scraper wear in additive-conditioned sand has been compared with that in water-conditioned sand to reveal the mechanism of foam additive and bentonite slurry. The soil additive parameters (solution concentration and injection ratio) were optimized to reduce scraper wear in abrasive sandy ground. The results indicate that the mitigation effect of the foam additive on scraper wear is related to the lubrication of the active agent and the cushioning of the air bubbles. The optimized foam solution concentration and foam injection ratio for the quartz sand samples are FSC = [5%, 10%] and FIR = [22.5%, 25.0%], respectively. The aggravation in scraper wear caused by bentonite slurry is related to the improvement of particle gradation and the increase of sand cohesion. The bentonite slurry parameters should be selected to keep the water content of the conditioned sand away from the peak water content to decrease scraper wear. [ABSTRACT FROM AUTHOR]

Taking Bingham slurry as the research object, an infiltration diffusion model of Bingham slurry in unsaturated soil is established based on the seepage theory of unsaturated porous media, which takes into account the displacement effect and the viscosity time-varying characteristics of slurry. Combined with the seepage motion equation, relevant boundary conditions and interface conditions, the Bingham slurry diffusion equation considers grouting parameters and mechanical parameters is obtained. The research results are degraded to the saturated state and compared with the existing theoretical results. Numerical examples are used to study the influence of the above parameters on grouting pressure and slurry diffusion radius, then the diffusion mechanism of Bingham slurry is verified and analysed by model test. The above analysis and test results confirm the effectiveness and applicability of the research results, which can provide reliable theoretical support and technical reference for the design and construction of grouting engineering in unsaturated soil areas. [ABSTRACT FROM AUTHOR]

The paper analyzed the economic transporting performance of k-epsilon turbulence models using the Eulerian two-fluid approach in transporting highly concentrated fine particulate slurry through horizontal pipelines using Kaushal et al. (2005) experimental data of glass beads slurry of 125 μm mean diameter for volumetric concentration ranging 30%–52% and flow velocity ranging 2–5 m/s. The primary components of economical slurry transport are Specific Energy consumption (SEC) and pressure drop; both have been examined in the performance of different κ-ϵ models and are yet to be unlighted on these parameters. The CFD model found the excellent performance of all k-epsilon models with slightly more effectiveness in the case of the Realizable κ-ϵ model. The analyzed and validated CFD model was subsequently used in examining the parameters of slurry flow, such as the secondary phase velocity, concentration distribution, and SEC analysis for the range of fine particles 125, 150, and 212 µm. The plotted contours from CFD are useful in visualizing slurry flow parameters at intermediates inlet values for slurry inlet flow velocity ranging 2–6 m/s and inlet volumetric concentration ranging 30%–55% for fine particles. Analysis revealed that the highly concentrated fine particles slurry transported at optimum volumetric concentration range of 40–45% are economical slurry transport. [ABSTRACT FROM AUTHOR]

A route preparing SiOC/SiC nanocomposites directly by pyrolysis of organosilane slurry residue was investigated. Organosilane slurry residue's unique composition, containing both silicon and carbon, offers an intriguing platform for developing advanced ceramic materials. The pyrolysis process is examined comprehensively, revealing the chemical reactions and structural changes leading to SiC crystals formation. The phase evolution at various annealing temperatures was revealed. Crystallization behavior in the process were studied. The results reveal that SiOC matrix was generated at annealed temperature 800°C and SiC nanoparticles were formed at 1300°C. In comparison to phase separation of SiOC, carbothermal reduction of SiO2 was domain in SiC formation. This research advances the understanding of SiOC/SiC nanocomposites, highlighting the value of repurposing industrial byproducts for sustainable and innovative materials development. [ABSTRACT FROM AUTHOR]

Microstructure‐tailored high porosity silicon carbide (SiC) ceramic foams were successfully fabricated using polymeric precursor slurry through a synergetic pore‐forming strategy that combines direct foaming and sacrificial template method together. The slurry is composed of a vinyl‐containing liquid polycarbosilane, poly(methyl methacrylate) (PMMA) microspheres, and composite inorganic fillers. The expandable PMMA served a dual role as both foaming agent and sacrificial template, while the liquid polycarbosilane was used as both binder and preceramic polymer. The green bodies foamed from precursor slurry were pyrolyzed at 1150, 1400, and 1600°C, respectively, to produce corresponding SiC ceramic foams. The pyrolysis behavior of the green body foams and the crystallization behavior of the SiC ceramic foams were studied. Notably, the SiC ceramic foam derived from the slurry containing 65 wt% filler exhibited low density (0.26 g/cm3), high porosity (90.3%), high compressive strength (3.87 MPa), and low thermal conductivity (0.34 W/mK). The SiC ceramic foams displayed attractive oxidation resistance, and the foams with a porosity of 90.3% can retain 75.2% of their initial compressive strength after oxidation for 10 h at 1400°C. [ABSTRACT FROM AUTHOR]

• A novel forced-air ice slurry wet precooling system is proposed and built. • The precooling experiments with tomatoes as cooling subject are carried out. • There is an optimal value of precooling uniformity with the increase of wind speed. • Weight loss and energy consumption are lower than those in traditional precooling. • The overall precooling effect is excellent when wind speed is 1.5–2.5 m/s. Aiming at the problems of low humidity and high dry consumption in the present forced-air precooling room, the combination of the ice slurry wet cooling system with the forced-air precooling was proposed, and a novel forced-air ice slurry wet precooling test platform was designed and built. The purpose of this paper is to experimentally study the effects of wind speeds on the performance of ice slurry wet precooling system by taking tomatoes as precooling objects, including precooling rate, precooling uniformity, precooling energy consumption and weight loss ratio of tomatoes. Also, the results are compared with those of other similar studies such as traditional forced-air precooling system. The results show that with the increase of wind speed, the precooling rate increases, the required precooling time is shortened, and the temperature variation coefficient of tomatoes decreases first and then increased, that is, the precooling uniformity becomes better and then worse. When the wind speed is 2.5 m/s, the overall precooling uniformity is the best. The precooling energy consumption decreases first and then increases, and is relatively low when the wind speed is between 1.5 m/s and 2.5 m/s (lowest at 2.5 m/s), which is lower than that of traditional forced-air system. With the increase of wind speed, the weight loss of tomatoes decreases first and then fluctuates slightly, and the weight loss ratio is about 0.1 %, which is much lower than that of tomatoes in the traditional forced-air precooling system. Overall, the maximum wind speed is not recommended to exceed 2.5 m/s for the precooling system studied in this work. The results can provide references for the further research and development of forced-air precooling technology. [ABSTRACT FROM AUTHOR]

The present work focuses on a double process involving additive manufacturing and joining of ceramic-resin green bodies, aiming to overcome the challenges of printing long-span and large-size ceramic specimens. Through partitioned 3D printing, individual green bodies were built and then joined together using either a single-phase slurry (Al 2 O 3) or a double-phase slurry (Al 2 O 3 and ZrO 2). The impact of sintered temperature, photocuring duration time, and sandwich layer thickness on the three-point bending strength of the joined specimens was investigated. The analysis of photocuring depth, thermogravimetry, and composition structure characteristics reveals two significant joining mechanisms, namely initial polymer network joining and ultimate grain bonding and growth joining, which play a crucial role in holding the connection shapes and enhancing the connection strength. Furthermore, the bending strength analysis indicates a positive correlation between sintering temperature and bending strength, while a negative correlation is observed between sandwich layer thickness and bending strength. The photocuring duration time has no significant impact on the bending strength. Finally, the double-phase slurry demonstrates superior connection performance, but the joining strength is decreased to 44.53 % of the sintered substrate specimens due to the presence of joining defects such as flow channel pores and lamellar gaps. These defects have prompted the development of lamellar structures, flow channel pores, and intercrystalline fracture regions, consequently reducing the overall strength. [ABSTRACT FROM AUTHOR]

The interfacial frictional resistance of anchor solids, bolt, and the surrounding soil of soil nails in the flexible support structures of frozen soil slopes is a key parameter for calculating and evaluating its stability. Based on a series of direct shear tests under the condition of a constant normal load boundary, the shear mechanical behavior of the interface between the soil and a cement slurry block under different soil temperatures, water contents, and normal pressures was studied, and the interfacial deformation mechanism was analyzed. The results show that in the thawing state, with the increase of water content, the shear surface moves from the side close to the soil to the side close to the cement slurry block. However, the shear plane is determined in the direct shear test, which makes the effect of the change of the soil's own strength on the interfacial shear strength smaller. In the frozen state, the behavior of the interfacial shear stress–shear displacement behavior at the same water content varies from strain-hardening type to strain-softening type with the temperature decreasing. The normal displacement is affected by temperature, normal pressure, and water content. At the same temperature, the maximum normal displacement gradually decreases with the increase of water content and normal pressure. At the same normal pressure and water content, the maximum normal displacement tends to increase and then decrease as the temperature drops. Still, the maximum normal displacement in the frozen state is more significant than in the thawing state. At the same water content and normal pressure, the interfacial peak shear strength shows a nonlinear increase with the decrease in temperature. At the same normal pressure and temperature, the interfacial peak shear strength delivers a linear increasing law with increasing water content. The peak interfacial cohesion increases with the decreasing temperature and increasing water content, and this phenomenon is more evident at lower temperatures. The interfacial friction angle does not change significantly with the rise in water content at the same temperature, but as temperature decreases, its average value increases significantly. The research results can provide a reference for the design of slope support structures in cold regions. [ABSTRACT FROM AUTHOR]

Slurry wall protection is the key to the success of the design and construction of underground diaphragm walls; however, in the analysis of its grooving mechanism, the original slurry in the surrounding environment was usually equivalated to the slurry pressure, while the slurry penetration characteristics and the formation of a filter cake were often neglected, leading to obvious defects in the existing literature. In this paper, by combining computational fluid dynamics (CFD) and the discrete element method (DEM), a model based on the strain softening constitutive equation was proposed to investigate the formation of a filter cake by the effects of slurry penetration and cementation and to calculate the stability of grooving. In this model, material parameters were used to describe the mechanical properties of the filter cake, and the microscopic parameters that were calibrated through experiments were used to explore the optimal particle radius ratio of the filter cake. Then, the feasibility and rationality of the model in describing the slurry penetration and failure trends were verified through comparative analysis. In the stability analysis, the safety factor was introduced to evaluate the impact of the slurry and other influencing factors on the grooving process. The results show that the properties of slurry and the environmental factors such as groundwater level have significant effects on the formation of the filter cake and stress distribution, thereby affecting the grooving effect. The findings of this study can provide useful guidance and reference for theoretical research and practical engineering. [ABSTRACT FROM AUTHOR]