Wet Sand Research Articles

The Preparation, Microstructure, and Wet Wear Properties of an Fe55-Based Welding Layer with the Co-Addition of 0.01 wt% CeO2 and 1.5 wt% SiC Particles Using the Plasma Beam Spraying Method

Severe erosion wear is found on valve spools, which threatens the safety and reliability of these units. The use of the plasma beam spraying surfacing method can significantly improve the corrosion resistance and sealing performance of hydraulic valve spools, reduce material waste, and reduce maintenance costs. The effects of the co-addition of CeO2 and SiC particles on the morphology, surface cracks, microstructure, precipitated phases, and wear property of plasma-beam-sprayed Fe55-based coatings on 1025 steel were investigated using OM, EDS, ultra-deep field microscopy, and a wet sand rubber wheel friction tester, respectively. The dendrite exhibited a directional growth pattern perpendicular to the substrate and the transitional states of the microstructure with the co-addition of CeO2 and SiC particles. CeO2 or SiC reduced the liquid phase diffusion coefficient DL of Cr and C and resulted in a decrease in the G/R ratio. The dendrites changed into equiaxed grains. The main phase composition of the Fe55 welding layer was Cr7C3, γ-Fe. The martensite in the surfacing layer and the carbides formed Cr7C3, which can improve the hardness of the surfacing layer. The grain boundaries consisted mainly of a reticular eutectic structure. The uniform distribution of the Cr7C3 hard phase in the Fe55+1.5 wt% SiC+0.01 wt% CeO2 resulted in a uniformly worn surface. The sub-wear mechanisms during the friction process were micro-ploughing and micro-cutting. The hardness and toughness of Fe55+1.5 wt% SiC+0.01 wt% CeO2 were well-matched, avoiding excessive micro-cutting and microplastic deformation. A low content of CeO2 could lead to the formation of equiaxed grain and effectively improve the uniformity of the microstructure. The wear-resistant layer of Fe55+1.5 wt% SiC+0.01 wt% CeO2 can effectively improve the service life and long-term sealing performance of the valve spools.

Wettability, flowability and core bending strength of wet silica sand particles based on the interfacial properties of liquid silicate binders

The flowability of wet silica sand particles containing liquid binders, which are among the new moulding materials for green casting, must be further improved. Herein, we conducted an in-depth study on the interface characteristics of silicate binders with the addition of anionic surfactants. Through particle flow experiments and sand core bending fracture experiments, the influence of anionic surfactants on the flow characteristics of wet sand particles and the mechanical properties of silicate-bonded sand was explored. The experimental results showed that the addition of 0.10 wt% of an anionic surfactant significantly reduced the surface tension and contact angle of solutions, from 78.99 to 28.53 mN/m, and from 49.9° to 34.4°. Moreover, compared with unmodified wet particles, the flowability of wet particles modified with 0.10 wt% of the anionic surfactant was improved to some extent. However, the flexural strength of silicate-bonded sand was also reduced to a certain extent.

Self-healing and rebar corrosion performance of cracked engineered cementitious composites exposed to wet coral sand environment

Wet coral sand environment on islands and reefs features high humidity and abundance in aggressive fluids and gases, thus posing a great threat to the durability of reinforced concrete structures. In this study, engineered cementitious composites (ECCs) with strain-hardening and self-healing characteristics are proposed as a potential cover material in wet coral sand exposure. The autogenous self-healing capability of cracked ECCs was evaluated by the visual crack morphology as well as water permeability, and their rebar corrosion performance over a period of one and a half years was investigated based on electrochemical tests. The results show that cracks with initial width up to 70 μm are able to completely close within one day, probably due to the efficient precipitation of calcium carbonate and further hydration of cement. Compared with the uncracked control, the 0.4 %, 1.0 % and 1.6 % strained ECCs can be healed up to 100 %, 93.4 % and 60.5 % at 30 days, respectively. The water permeability coefficient of the strained ECC decreases rapidly in the first 30 days, and then stabilizes in the later stages. Moreover, the load-carrying capacity of preloaded ECC beams is recovered, exhibiting comparable performance to the uncracked controls after the same exposure periods. The corrosion current densities of steel bars suggest an active corrosion conditions. Both of the corrosion current densities and mass losses of rebar show lower values at decreased strain level, which is closely related to the width and number of cracks that reach the reinforcement.

Study on screening process and segregation mechanism of wet sand and gravel particles based on discrete element method

Study on screening process and segregation mechanism of wet sand and gravel particles based on discrete element method

Well Log Analysis and Comparison of Supervised Machine Learning Algorithms for Lithofacies Identification in Pab Formation, Lower Indus Basin

Machine learning uses higher-order statistical computation for model prediction by combining statistics with advanced algorithms. These predictions can be used to infer the characteristics of potential hydrocarbon reservoirs using well log data. The objective of this study is to predict and segregate the potential reservoir and non-reservoir facies in the Cretaceous Pab Formation based on well log analysis and machine learning techniques using the borehole data of three wells drilled in the Lower Indus Basin. The Petrophysical interpretation has been performed to mark the potential reservoir facies, namely, gas sand, wet sand, and shale using cutoff values for shale volume (Vshale) and water saturation (SW). Before any further analysis, the quality of the well log data for the wells was checked by using heat maps and box plots to identify the outliers in the available dataset. The important available featured logs were used in the Random Forest (RF) and the Decision Tree (DT) algorithms to predict the facies in each well by training the other two wells. The prediction accuracy score between the petrophysical and the predicted potential reservoir facies using RF classifier shows 92 to 94% accuracy, whereas prediction accuracy score of DT classifier is 80 to 85%. The comparison of the two techniques indicates that the predictions using RF algorithm are relatively more accurate therefore making it more efficient for predicting the potential reservoir facies in the wells where the sophisticated well logs are unavailable.

Development and Research of Technology for Obtaining a Steel Casting Using a Cold-hardening Mixture

Fundamental in acquiring the required operational properties of cast products depends on many factors, the main of which are the quality of the mold itself, the mold materials for its manufacture, as well as the choice of the optimal parameters of the technological process modes and the properties of the mold materials themselves. In the foundry industry, the choice of mold material and casting method is a complex task. There are several types of molding, but more than 70% of all metal castings are usually developed using sand molding (SMF). Sand casting consists of two processes such as wet sand casting and chemical bond sand casting process. The article focuses on chemical bonded sand casting, i.e. non-sintering systems (cold self-hardening system) cured with epoxy resin. The mechanism for producing castings using cold hardening mixtures is shown, and in a comparative form in SMF. Next, the microstructures of the obtained samples are investigated, and the results of testing for mechanical properties are described.

Rare earth elements in sands collected from Southern California sea beaches

Rare earth elements (REEs) are considered the limiting resources for advancing clean technologies and electronics. Because global REEs reserve is limited, non-conventional and secondary sources are being investigated for recovery. Here, we investigated wet and dry sand from seven Southern California beaches for sixteen REEs. These include five light REEs, two medium REEs, and nine heavy REEs, separated by their atomic weight. The mass of the magnetically separated compounds ranged from 15.19 to 129.91 g per kg of dry sand in the studied sea beaches in Southern California. The total REEs concentration ranged from 1168.1 to 6816.7 μg per kg of wet sand (dry sand basis) and 1474.7–7483.8 μg per kg of dry sand. Cerium (Ce) and Yttrium (Y) were the most prevalent REEs in these beaches ranging from 387.4 to 2241.1 μg kg−1 and 104.5–2302.3 μg kg−1 of sand respectively. This study found light REEs concentration accounted for 70–80% of total rare earth elements in the studied beaches. The concentrations of the analyzed REEs were significantly different (p < 0.05) from each other in the studied beaches. Additionally, Pearson correlation showed that the REEs were strongly correlated (r ≥ 0.83) with each other in the reported sea beaches, indicating a similar origin of the REEs. The dominant heavy metals in the studied samples were Vanadium (V), Chromium (Cr), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn), and Strontium (Sr). Dominant minerals identified in sands were quartz, anorthite, ilmenite, and xenotime. All the beaches are lowly enriched with REEs, and any of the REEs caused no ecological risk or pollution. Similarly, no pollution/ecological risk was observed for the analyzed heavy metals. This study identified beach sand as a potential REEs source and demonstrated an easy separation of REEs containing magnetic compounds from sand.

Investigation of deformation coordination between optical fibre and borehole sand backfill

Land subsidence has threatened the safety of municipal infrastructures and even that of inhabitants. As one of the deformation monitoring methods, distributed optical fibre sensing (DOFS) technology has been developed for the investigation of land subsidence. The deformation coordination between the optical fibre and soil (DCf-s) under different conditions is critical for land subsidence monitoring with DOFS. In this paper, a medium-sized triaxial apparatus was modified for testing the DCf-s. Consolidated drained triaxial tests were conducted to investigate the effect of sand types on the DCf-s. By linearly fitting the deformation of the sensing cable with that of the triaxial specimen, the other factors that affect the DCf-s, such as the confining pressure, dry or wet state of the soil and cyclic variation of the loads, can be discussed. The experiments reveal that better DCf-s comes with a larger particle size, poor gradation of sand and larger confining pressure. The DCf-s of wet sand is better than that of dry sand. The DCf-s coefficient tends to be stable with an increase of loading cycles. The DCf-s obtained and its dependence on influencing factors can be used to modify the measured cable strain in practical land subsidence monitoring with DOFS.

Wetting characteristic and flow behavior of silicate binder at various sand particle-particle interfaces: Fine or coarse, circular or angular particles

This study presents an innovative investigation into the wetting characteristic and flow behavior of sand particles, which have different shapes, sizes, and textures, when they bonded with silicate binder. The results revealed that the apparent contact angles of fine and angular particles with the binder are higher than those of coarse and circular particles. In addition, after modifying the four systems with anionic surfactants, the equilibrium contact angles decreased by 42.8%, 26.7%, 26.5%, and 7%. These findings suggest that coarse and circular particles demonstrate stronger wetting properties with the binder compared to fine and angled particles. Additionally, the cohesion and internal friction angle of the wet sand mixture can be measured through the ring shear test. Moreover, the unconfined yield strength and main consolidation stress can be calculated using the Mohr Coulomb model to obtain the yield locus and quantify the flowability of the wet sand mixture. The yield trajectory of sand mixtures at specific consolidation stresses suggests that the most important factor affecting the flowability of wet sand particles is particle size distribution. Wet mixtures of coarse and circular particles exhibit lower cohesive forces, indicating higher fluidity.

Uniplanar multirod TDR probe for soil water content measurement over a larger spatial scale

AbstractThis study developed a uniplanar multirod time domain reflectometry (TDR) probe and evaluated it in laboratory experiments for soil water measurement over a larger spatial scale. The sampling volume of the probe was determined by simulating the electric potential distribution around the probe rods by using the HYDRUS‐2D software package and verified by comparison with the measured dielectric constant in saturated sand. The performance of the probe was evaluated by comparing its dielectric measurements in wet sand over a wide range of water content during evaporative drying with that measured by CS640 probes. Additionally, the dependency of visible light reflection on the water content of the sand was evaluated. The results revealed that the average effective thickness of the probe's sampling volume was 5–6 cm on both sides of the plane of the probe rods. The probe accurately measured the soil water content over a 0.88 m2 spatial area. The visible light reflectance of the variably saturated sand surface and the corresponding water content of the sand follow a soil water retention function‐type relationship. The usage of the multirod TDR measurement system at a larger spatial scale carries practical implications, especially in increasing the accuracy of remote sensing data.

Subcritical CO2 adsorption on geomaterials of coal-bearing strata in the context of geological carbon sequestration

This paper explores the adsorption behaviour of geomaterials in the framework of CO2 sequestration in shallow level coal seams. Manometric adsorption experiments were carried out on two anthracite coal samples, two rock samples from East Irish Sea, MX80-bentonite, Speswhite kaolinite, dry, wet and biofilm-laden (Bascillus mojavensis-laden) sand at subcritical pressure range (up to 6.4 MPa) of isothermal condition at 298.15 K. The experiments were aimed to investigate the influence of the biogeological conditions of coal and caprock constitutions on CO2 adsorption. At lower pressures, the moisture had an influence on the CO2 adsorption on coal resulted in reduced adsorption capacity. At elevated pressures, the volume expulsion behaviour and coal-water interaction had an influence on the adsorption capacities of moist coal sample and resulted in comparable adsorption capacities to dry sample. The disparity in the adsorption capacities between the wet powdered and wet intact core samples showed that the results obtained with powder samples may not reflect the field conditions. Wet conditions and Bascillus mojavensis bacteria influenced the adsorption capacity of sand and showed CO2 chemisorption capacity. The desorption isotherm pattern of wet and biofilm sand showed that the CO2 was continuously adsorbed independent of the gas phase pressure. Among the clay minerals, bentonite had greater affinity towards CO2. Despite the fact that the adsorption capacity of the cap rock is smaller than that of the coal samples, the experimental investigation with constituents of the cap rock provides insights into the effect of biogeological conditions of coal and rock sample constituents on CO2 storage in coal seams.

Deep Rock Blasting Using Decoupled Charge with Different Coupling Mediums

Blasts using decoupled charge with various coupling mediums are extensively operated in underground excavation, and blasting challenges are always encountered in deep rock mass due to the influence of high in-situ stress. In the present study, the dynamic responses of deep rock mass in blasting with decoupled charge and different coupling mediums (air, dry sand, wet sand, and water) are theoretically and numerically investigated. First, the transmission, propagation, and superposition of stress induced by blasting coupled with different coupling materials, and the effect of static stress distribution around boreholes on the crack initiation and propagation in blasting under conditions of varying hydrostatic pressure and anisotropic in-situ stress are theoretically analyzed with a two-hole planar analytical model. Then, a numerical model is constructed and verified against the rock fracture network obtained from a blasting test. Based on the verified numerical model, two-hole planar computational models with the same configuration as the analytical model are developed and used to perform a series of simulations. The joint effect of the coupling medium and the in-situ stress on the initiation, propagation, and interconnection of blast-induced cracks are numerically analyzed and interpreted by combining with theoretical results. The analytical and numerical investigations indicate that the evolution of blast-induced cracks in deep rock mass is mainly controlled by the stress transmitting from explosive to rock, superposition of explosion stress waves, as well as the magnitude and orientation of in-situ stress. Finally, the implications of current findings for practical blasting in deep rock mass are discussed. This study develops the understanding of rock cracking induced by blasting with different coupling mediums under high in-situ stress and provides some guidance to solve blasting difficulties in deep rock mass.

Quantitative analysis of experimental trackways of scorpions, tarantulas, and crayfish

ABSTRACT Previous neoichnological studies with arthropods, especially arachnids, have often conducted experiments with only a small number of trackways produced in a subset of subaerial conditions. Thus, we conducted a comprehensive neoichnological study of scorpions (Hadrurus arizonensis), tarantulas (Grammostola rosea), and crayfish (Procambarus clarkii), under various moisture levels (dry, damp, wet drying, wet saturated, and subaqueous [or wading]) and horizontal, shallow, and steep slope angles. The invertebrates made a total of 473 trackway runs resulting in 489 symmetric trackway segments that were characterized and digitally measured. We analyzed the trackways using trackway parameter trend diagrams and non-metric multidimensional scaling (N-MDS) visualizations to compare trackway morphology among the sand moisture conditions. Results generally show imprints become progressively smaller, with more dotted multifid imprints going from loose to stiff sand. N-MDS showed trackway morphology overlapped among some conditions, including those with disparate water content (e.g. dry and wet saturated sand, or subaqueous and wet drying sand). Additionally, trackways consisted usually of a four-imprint series, though species- and condition-specific exceptions were found. Interestingly, the scorpions rarely dragged their metasomas, while the crayfish always dragged their tail fan except sometimes underwater. Our neoichnological photos and quantitative dataset provide a basis for future comparative ichnological studies.

Effect of Nano-Y2O3 on the Microstructure and Properties of Fe-Cr-C-N-Al Surfacing Alloy

In this paper, Fe-Cr-C-N-Al-Y wear-resistant surfacing alloy was prepared by open-arc surfacing with self-shielded flux-cored wire. The wear properties of the surfacing alloy were analyzed using an MLS-23 rubber wheel wet sand wear tester. The phase composition and microstructure of the surfacing alloy were analyzed using X-ray diffraction, scanning electron microscope, electron backscatter diffraction and transmission electron microscope; the strengthening mechanism and wear mechanism of the alloy were discussed. The results show that the microstructure of Fe-Cr-C-N-Al-Y surfacing alloy is composed of M + γ-Fe + M7C3 + AlN. When the content of nano-Y2O3 is 0.456 wt.%, the formability of the surfacing alloy is the best, and the wetting angle is the smallest, which is 50.8°; AlN and M7C3 precipitate the most, and the microstructure grain is the smallest. At this time, the hardness value of the surfacing alloy is up to 62.3 HRC, which is 11.8% higher than that of the unmodified surfacing alloy. The minimum wear weight loss is 0.125 g, and the wear resistance is increased by 41.86%. The wear mechanism of the surfacing alloy is mainly a plastic deformation mechanism, and the material removal processes are microcutting and furrow wear. This study provides theoretical guidance for refining primary carbides and improving the wear resistance of high chromium cast iron.

Effect of Crumb Rubber on the Moisture and Rutting Behavior of Low-Energy Asphalt and Determining the Best Flow Number Model

The advancement of technology and the increasing growth of environmental threats have led experts in the field of transportation to find alternatives for hot mix asphalts (HMAs). One of these alternatives is low-energy asphalt (LEA) mixtures. LEA mixture consists of hot asphalt binder and coarse aggregates and wet sand, which, having a lower mixing temperature, has caused a significant reduction in energy consumption and pollutants emitted from asphalt binder. According to previous studies, the influence of crumb rubber (CR) on the rutting and moisture performances of LEAs has not been investigated so far. In this regard, due to the softness of this type of asphalt mixture and its weakness against rutting and moisture, in this study, as an innovation, CR was used to modify LEA mixtures in three weight percentages of 10, 15, and 20. Considering the high moisture sensitivity of LEA mixtures due to the presence of water, the ability of CR to overcome this weakness and its potential to be replaced with antistriping additives were also investigated using the indirect tensile strength (ITS) test. In addition, in order to evaluate the rutting resistance, LEA mixtures were subjected to the dynamic creep test at a temperature of 54.4°C and at two stress levels of 270 and 310 kPa. According to ITS test results, it was found that although the modified LEA mixtures with 10 and 15% CR met the minimum requirement, the tensile strength ratio (TSR) value recorded for mentioned mixtures was still lower than that for HMA. Therefore, it is recommended to use antistripping additives in the use of LEA-containing CR, especially in areas with a high probability of moisture damage. The results of creep curves and flow numbers (FNs) extracted from four different models of three-stage, Fnest, Francken, and stepwise showed that although the LEA sample without additive had lower rutting resistance than HMA, the modification of this mixture to 15% CR significantly increased the rutting resistance. Moreover, considering the variety of variables in the process of making LEA compared to HMA, the comparison of FN determination models and the introduction of the most stable model were conducted in this research. According to the laboratory and statistical analysis results, it was found that the Francken model had less sensitivity to the variables, so it is suggested to determine FN for LEA mixtures.

Application of microgel latex in water-based drilling fluid to stabilize the fractured formation

Fractured formations are complex formations often encountered during oil and gas drilling. Conventional methods such as plugging formation fractures and pores, improving cutting-carrying efficiency, and inhibiting hydration of cements cannot effectively solve the problem of wellbore instability in fractured formations. In this paper, an adhesive microgel latex (MGL) was prepared to improve the cementing strength of fractured formations. The morphology and thermal property were analyzed by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), etc. The plugging effect of MGL was then studied by visualized plugging experiments and high temperature and high pressure (HTHP) plugging experiments. The evaluation methods for strengthening fractured formation were established, including immersion test, single lap test and compressive strength test, and applied to evaluate MGL. The experimental results show that MGL were spherical particles with a median particle size of 38.9 μm and a glass transition temperature of 61.98 °C. MGL could effectively decrease drilling fluid intrusion and plug fractured formations. Wellbore strengthening experiment showed that MGL could enhance the cementing strength of fractured formations. MGL greatly improved the tensile shear strength between core pieces and cementation strength of the fractured formation. After treatment of MGL, the tensile shear strength between core pieces increased by 81.2% compared to asphalt, and the compressive strength substantially increased for both wet and dry sand cores. The mechanism analysis suggests that the adsorption between MGL and rock matrix and the self-adhesion among MGL particles are responsible for wellbore strengthening. This paper innovatively proposes the use of adhesive particles to enhance wellbore stability in fractured formations.

Tribological Study of Chisel Knives in Sandy Soil

This paper presents the interaction system within the mechanical soil processing process, consisting of two large elements, the metal of the tool and the soil. Due to the two main forces acting on the chisel knives—friction and impact with the sandy soil—the wear of these chisel knives was determined. To determine the wear, a stand was used which allowed testing chisel-type knives in laboratory conditions by changing their functional parameters: working depth, angle of the knives to work the soil, working speed, humidity and granulation of the test environment. The present paper presents an application of the Archard-type wear law to the contact between a chisel-type knife and sandy soil (wet and dry sand). The theoretical model regarding the Archard wear coefficient considered three forms of surface damage (shake down, ratcheting and micro-cutting). The sand was considered spherical and rigid and the surface of the knife was flat. The experimental model considered real steel knives with different surface hardness and operation under controlled conditions of sand granulation, humidity, attack angle, depth of penetration and speed of sliding. The theoretical and experimental results highlight the wear behavior of chisel knives (Archard coefficient) in wet and dry sand.

An Investigation to the Abrasive Wear in Pipes Used for Oil Industry

The work reported in this study focusing on the abrasive wear behavior for three types of pipes used in oil industries (Carbone steel, Alloy steel and Stainless steel) using a wear apparatus for dry and wet tests, manufactured according to ASTM G65. Silica sand with hardness (1000-1100) HV was used as abrasive material. The abrasive wear of these pipes has been measured experimentally by measuring the wear rate for each case under different sliding speeds, applied loads, and sand conditions (dry or wet). All tests have been conducted using sand of particle size (200-425) µm, ambient temperature of 34.5 °C and humidity 22% (Lab conditions).The results show that the material loss due to abrasive wear increased monotonically with the applied load at constant sliding speed and constant grit size due to increasing depth of penetration in both dry and wet sand which agrees with Archard´s equation. Sliding speed show insignificant effect on the wear loss of metals at constant load and constant grit size in both dry and wet sand. Wet sand results show higher wear losses than dry sand (20-70) % due to micro abrasion – corrosion wear and high slurry concentration.

Collection and preparation of raw materials for the refractory industry

The characteristic of sand, which is the raw material of silicate and clay bricks, glass and mineral fibers, is given. Sand is a part of ceramic products used for the production of refractory products. A number of vehicles for collecting dust-forming materials are proposed. A trowel unit has been developed for collecting sand in a quarry. A fluidized bed drying unit for drying wet sand with a detailed description of its operation is proposed. Ill. 2. Ref. 11.

Implementation and Performance Evaluation of a Community-Scale Adobe Evaporative Cooling Chamber for Vegetable Preservation

The construction of evaporative coolers in remote areas can increase the longevity of vegetables, improving food security and the local economy of small farmers in remote, impoverished communities without access to electricity. This work presents a 1:1 scale prototype of an 8 m3 (2.1 × 2.1 × 2.3 m) stabilized adobe evaporative cooler, with a design based on the appropriate technology framework, and it was built as a chamber using double adobe walls, filled with wet sand, to induce evaporative cooling. Furthermore, the paper presents the prototype’s performance evaluation. The tests were carried out in the dry and wet states, with different volumes of water. The results show good performance compared with other prototypes, although the optimum watering volume could not be determined because of the high climate variance (outside temperature and humidity) that prevented the repetition of the experiments in identical operating conditions. Stabilized adobe proved to be a good choice for use in the cooler, even when subject to moisture accumulation, indicating an estimated long lifetime for the cooler. The data obtained about the efficiency of evaporative cooling show that the cooler, as expected, has its best performance on the hottest and driest days, reducing the internal temperature (up to 13.24 °C) and managing to keep the internal humidity. The cost, efficiency, durability, and replicability make the proposed evaporative cooler a feasible solution for food preservation.