Sand Gradation Research Articles

Development of a vision‐based online soft sensor for oil sands flotation using support vector regression and its application in the dynamic monitoring of bitumen extraction

AbstractExtraction from oil sands is a crucial step in the industrial recovery of bitumen. It is challenging to obtain online measurements of process outputs such as bitumen grade and recovery. Online measurements are a prerequisite for innovating better process control solutions for process efficiency and cost reduction. We have developed a soft sensor to provide online measurements of bitumen grade and recovery in a flotation‐based oil sand extraction process. Continuous froth images were captured using a VisioFroth camera system on a batch flotation unit. A support vector regression (SVR) model with a Gaussian kernel was constructed to develop a soft sensor for bitumen grade and recovery using froth image features as the inputs. The model was trained and validated for batch flotation of different grades of oil sands ore at industry‐relevant process conditions. A Dean‐Stark analyzer was used to obtain offline grade and recovery measurements that were used to calibrate the soft sensor. Mean squared errors (MSE) of 62 and 74 were achieved for grade (%) and recovery (%), respectively, and this was obtained using 5‐fold cross validation. The developed soft sensor model has been applied successfully in the real‐time dynamic monitoring of flotation grade and recovery for different grades of ore and operating conditions.

Effect of Sandblasting Process on Mechanical Properties of ASTM A516 Grade 70 Steel

Sandbalsting is a method used for surface treatment and at the same time this process also improves the mechanical properties of the material. ASTM A516 Grade 70 is widely used in industrial sector as it provides very good mechanical properties in tough conditions. The main usage of this material is in moderate and low operating services. This paper focus on the effect of sandblasting process on ASTM A516 Grade 70 on improving the mechanical properties and fatigue life of this material. Samples have been blasted with sand grade SAE G-80. The focus of this paper is the result of the microhardness, tensile and fatigue test before and after the sandblasting process to study the improvement in mechanical properties as well as the fatigue life. The research was extent to the microstructure analysis using SEM to study the change in microstructure after sandblasting process and fatigue test. Result shows that the hardness increases with respect to blasting time. Result also shows 2.3% increment in tensile strength after sandblasting and there is significant increment in fatigue life. Result also shows that the sandblasting process decreases the grain size of the material. It was proven that the sandblasting process will increase the hardness and decrease the grain size of the material with respect to sandblasting time. At the same time, there is a significant improvement in mechanical properties and fatigue life by applying sandblasting process on the tested material.

STUDY GRADATION AND MOISTURE CONTENT OF SAND EMBANKMENT ON PEAT SUBJECTED VIBRATION POTENTIAL LIQUEFACTION

In recent years large earthquakes often occur on the island of Sumatra. There is a phenomenon of the damage occurred during the earthquake, one of the effects is a phenomenon of loss of soil strength due to vibration called liquefaction. Some cases of liquefaction occur in some areas in Aceh, Nias Island, Padang and Pariaman. Pekanbaru is located close to the fault area that causes the occurrence of earthquake wave propagation. Pekanbaru are also at risk for geotechnical problems because of earthquake such as liquefaction. Evaluation of liquefaction potential could using by in-situ test and by laboratory test. The laboratory test to evaluation liquefaction potential among which method of experiment shaking table. In this study, liquefaction phenomenon was conducted by creating a physical model of a laboratory scale using a one-way vibration machine, with a review of how big the influence of sand gradation, sand shaped and grain-size, and surface water level in the sand against liquefaction potential. Evaluate of liquefaction potential based on the surface reading of the soil movement, elapsed time for final settlement and an excess pore water dissipation (EPD) during testing. Based on the results of performed test, indicated that fine sand on fully saturated conditions have the potential of maximum settlement for 20.67% and maximum ascend of pore water for 46.67%. This result mean that poorly graded fine sand on fully saturated conditions has more liquefaction potential than medium sand, coarse sand, and well graded sand

Development of an optimum mix design method for self-compacting concrete based on experimental results

The main objective of this study is to develop an optimum mix design method for self-compacting concrete (SCC) based on experimental results. For this purpose, mix design of self-compacting concrete is formulated as an optimization problem. Given the importance of manufacturing costs of concrete, the total cost of one cubic meter of self-compacting concrete is considered as the objective function in the optimization problem, which must be minimized. Limitation of the 28-day compressive strength and slump flow of self-compacting concrete are considered as the main inequality constraints. To ensure that sum of concrete components makes unit volume, an equality constraint is considered. To formulate the self-compacting concrete mix design optimization problem based on experimental data, forty-two different mix designs of self-compacting concrete are presented and three cylinder specimens are made and tested for each of them. Two mathematical models are developed to estimate the strength and the slump of the concrete and used to define the main constraints in the mix design optimization model. The concrete specimens are prepared in a construction site in Sanandaj in Iran. Considering importance of sand grading on the compressive strength of self-compacting concrete, stone powder is used to improve sand fineness modulus. The sequential quadratic programming is employed to solve the optimal mix design problem of self-compacting concrete based on proposed model. In order to verify the proposed method, the mix design problem is solved for several case studies and then the final optimal mix designs are made in laboratory and mechanical properties of specimens are evaluated. The results show that the proposed method satisfies the mechanical characteristics of the self-compacting concrete, besides minimizing the cost of the concrete and automating the mix design process.

Multisensor Analysis of Spectral Dimensionality and Soil Diversity in the Great Central Valley of California.

Planned hyperspectral satellite missions and the decreased revisit time of multispectral imaging offer the potential for data fusion to leverage both the spectral resolution of hyperspectral sensors and the temporal resolution of multispectral constellations. Hyperspectral imagery can also be used to better understand fundamental properties of multispectral data. In this analysis, we use five flight lines from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) archive with coincident Landsat 8 acquisitions over a spectrally diverse region of California to address the following questions: (1) How much of the spectral dimensionality of hyperspectral data is captured in multispectral data?; (2) Is the characteristic pyramidal structure of the multispectral feature space also present in the low order dimensions of the hyperspectral feature space at comparable spatial scales?; (3) How much variability in rock and soil substrate endmembers (EMs) present in hyperspectral data is captured by multispectral sensors? We find nearly identical partitions of variance, low-order feature space topologies, and EM spectra for hyperspectral and multispectral image composites. The resulting feature spaces and EMs are also very similar to those from previous global multispectral analyses, implying that the fundamental structure of the global feature space is present in our relatively small spatial subset of California. Finally, we find that the multispectral dataset well represents the substrate EM variability present in the study area – despite its inability to resolve narrow band absorptions. We observe a tentative but consistent physical relationship between the gradation of substrate reflectance in the feature space and the gradation of sand versus clay content in the soil classification system.

Recycled Glass Concrete: Coarse and Fine Aggregates

Conventional concrete aggregate consists of sand (fine aggregate) and various sizes and shapes of gravel or stones (coarse aggregate). However, there is a growing interest in substituting alternative aggregate materials, largely as a potential use for recycled materials. While there is significant research on many different materials for aggregate substitutes such as granulated coal ash, blast furnace slag or various solid wastes including fiberglass waste materials, granulated plastics, paper and wood products or wastes, sintered sludge pellets and others. Recycled waste glasses were used as coarse and fine aggregates replacement in concrete. Coarse aggregates were replaced with Green Bottles coarse aggregates at third, half, two thirds, and 100% replacement ratios. The replacement of a third coarse aggregate was established as being the most suitable for retaining the properties of the concrete mix design. As for fine aggregates, in order to account for the numbers of variables and clearly establish a bench mark, the sand grading, color of glass, source of waste glass (bottles and non-bottles), and design mix strength were used as parameters. Fine aggregates from green, brown, and transparent bottles in addition to clear window waste glass were used. Concrete properties were tested in fresh and hardened states. The incorporation of glass sand regardless of the ratios of replacement showed no significant influence on fresh or mechanical properties of concrete except for the case of transparent bottles. Transparent bottles due to the wide source of obtainability have introduced a non-uniform factor that caused discrepancy compared to the rest of the group.

Recycled Glass Concrete: Coarse and Fine Aggregates

Conventional concrete aggregate consists of sand (fine aggregate) and various sizes and shapes of gravel or stones (coarse aggregate). However, there is a growing interest in substituting alternative aggregate materials, largely as a potential use for recycled materials. While there is significant research on many different materials for aggregate substitutes such as granulated coal ash, blast furnace slag or various solid wastes including fiberglass waste materials, granulated plastics, paper and wood products or wastes, sintered sludge pellets and others. Recycled waste glasses were used as coarse and fine aggregates replacement in concrete. Coarse aggregates were replaced with Green Bottles coarse aggregates at third, half, two thirds, and 100% replacement ratios. The replacement of a third coarse aggregate was established as being the most suitable for retaining the properties of the concrete mix design. As for fine aggregates, in order to account for the numbers of variables and clearly establish a bench mark, the sand grading, color of glass, source of waste glass (bottles and non-bottles), and design mix strength were used as parameters. Fine aggregates from green, brown, and transparent bottles in addition to clear window waste glass were used. Concrete properties were tested in fresh and hardened states. The incorporation of glass sand regardless of the ratios of replacement showed no significant influence on fresh or mechanical properties of concrete except for the case of transparent bottles. Transparent bottles due to the wide source of obtainability have introduced a non-uniform factor that caused discrepancy compared to the rest of the group.

Effect of embedment length of untreated natural fibres on the bond behaviour in cement mortar

The present investigation is focused on studying the effects of various matrices with 1:3, 1:4 and 1:5 mortars and fibre types of sisal and coir on the bond behavior at various ages of curing, i.e., 24 h, 3 d, 7 d and 28 d. The other parameters included in the investigation are water/cement (w/c) ratio, sand gradation and embedment length of fibres. In addition, the type of failure of sisal and coir fibres for different mixes of mortars at various curing ages is also reported. From the results, it is seen that the bond strength is improving with respect to age of curing in case of sisal fibres, but decreases in case of coir fibres. The failure of fibres due to fibre fracture is observed in sisal fibres and fibre pullout is observed in coir fibres. The other varying parameters such as mortar mixes, sand gradation, w/c ratio and embedded length also showed significant effect on bond behaviour of sisal and coir fibre with the cement mortar mixes.

Design 3D printing cementitious materials via Fuller Thompson theory and Marson-Percy model

Cementitious materials for 3D printing have special requirements for rheological properties, which are significantly affected by many factors, including sand gradation and packing fraction. Fuller Thompson theory and Marson-Percy model are classic approaches for sand gradation and packing fraction optimization, respectively. This paper attempts to apply Fuller Thompson theory and Marson-Percy model in designing cementitious materials for 3D Cementitious Materials Printing (3DCMP). Various gradation methods adopted in this study were Fuller Thompson gradation (mixture A), uniform-gradations (mixture B and C), gap-gradations (mixture D and E). Besides these mixtures with special gradation approaches, one mixture using natural river sand (mixture F) was prepared as well. Rheological properties were characterized by static/dynamic yield stress and plastic viscosity in Bingham Plastic model. Buildability was examined by printing a column with 10 cm inner diameter via a gantry printer. Rheological test results indicate that mixture A designed by continuous gradation possesses the highest static/dynamic yield stress and lowest plastic viscosity. During printing test for buildability, mixture A can easily reach up to 40 layers without notable deformation, while all other mixtures deformed noticeably and fell down before the 35th layer. Finally, a large-scale printing was carried out with mixture A and a structure with the height of 80 cm was printed successfully without notable deformation. Density, compressive strength and flexural strength of printed filaments were also characterized. Mechanical performance test results illustrate mixture A has the highest density and appropriate compressive strength, and a relative high flexural strength at different curing ages. These results indicate that Fuller Thompson theory and Marson-Percy model can serve as a reasonable guide for material rheology design for 3DCMP.

Sand Gradation in Seasonal Rivers and their Suitability for Construction of Sand Dams in Kitui South, Kenya

This study was undertaken in Kitui South in Kitui County in the south eastern parts of Kenya. The main objective of the study was to develop a spatial model that can be used for selection of suitable sites for sand dam in Kitui South. The study also assessed the spatial variation of sand grain sizes and how these determine the suitability of sites for the sand dams. Data analysis was done using three approaches. The first approach involved the use of the Remote Sensing (RS) technique where data was preprocessed and analyzed using Erdas Imagine software and Geographical Information Systems (GIS) for spatial modelling. The distribution of sand particle-sizes was based on sieve analysis on the sand samples collected from seasonal rivers in the study area. The seasonal rivers that were investigated in this study included Mwila, Kakya, Wiitu, Nguni, Ngunyumu, Muvuko, Kanzilu, Masaa, Katiliku, Ngulungu, Nzeeu, Koma and Katitika. Statistical analysis was done to establish the relationships between the various spatial components affecting sand particle distribution. The results from the spatial model which integrated all factors shows that 16% of the studied sites along the seasonal rivers in Kitui South were fairly suitable for construction of sand dams while 79% were classified as suitable and 5% are categorized as very suitable. Several sites in the central and the entire eastern parts of Mutha Ward were found not suitable for sand dam construction due to poor conditions such as the lack of suitable sand particles, lack of bedrock exposure on the riverbeds, flat terrain, very shallow stream banks, and weak soils on the riverbanks. Suitable sites for sand dams were found on the western and central areas of Kitui South where production and high accumulation of coarse sands was observed along the seasonal rivers. The areas near Mutomo hills and the rocky areas in Ikanga wards were found to be characterized by few excellent sites for sand dams. The optimum accumulation of different grades of sand in the seasonal rivers was found on streams with slope of between 1.5 and 6% that were dominated with 0 to 40% coarse sands, 0 to 30% fine gravels, 0 to 20% fine sands, and 20 to 80% medium sands. The accumulation of fine gravels was found to be closely related to the distribution of D30, D60 and D90 sand particle-sizes (0.4-4 mm) while accumulation of coarse sands showed good relationship with the distribution of the medium size sand (0.2-0.4 mm). The accumulation of medium sands was equally high when the occurrence of coarse sands was minimal. Different grades of sand were found to be strongly influenced by the changes in the elevation of the stream especially with regard to the accumulation of the medium sands (r=0.76) and coarse sands(r=0.75). Out of 80 investigated sites, 59% of them were dominated with uniform sands (Cu 5). The study also found that 86% of the sites along the seasonal streams were dominated with medium sands while 10% were dominated with fine sands and the rest (4%) dominated by coarse and gravelly sands. From the results this study concludes that 59% of the 80 sites that were investigated in this study have a high potential for providing suitable sites for sand dams in Kitui South.

Investigation of changes in the physical properties of the sandy soil in geotechnical control of the road embankment

The aim of this work is to determine the effect of “temperature-precipitation” climate parameters on the physical properties of sandy soil of an embankment during the construction period. The object of this study is sand from a quarry and the upper layer of the road embankment before and after the climatic effect during the “autumn-winter-spring” period. The results of this study revealed changes in sand gradation, coefficient of permeability and void ratio of a sandy soil after the influence of “temperature-precipitation” climate parameters during a short time period. The results of this study can be used for geotechnical control of construction process.

Effect of aggregate properties on the mechanical and absorption characteristics of geopolymer mortar

Even though aggregate constitutes major volume in geopolymer concrete, only limited study related to this parameter has been reported. This paper presents the summary of study carried out to understand the influence of aggregate content and grading on the mechanical and absorption characteristics of geopolymer mortar. Three types of aggregates, namely, natural river sand, crushed limestone, and combined sand-limestone were used in geopolymer mortar. Fly ash was used as source material. Effectiveness of aggregates was evaluated in terms of the workability, fresh unit weight, absorption and strength of geopolymer mortar. The alkaline activator is a mix of 12 molarity of NaOH solution with Na2SiO3 in ratio of 1:2.5. The experiments were performed on geopolymer mortar cubes under curing temperatures of 90 °C with curing period of 24 h. Test results indicate that geopolymer mortar including natural sand shows better flowability compared to other aggregates, moreover, coarse grading of sand caused higher flow. The highest compressive and splitting tensile strength was obtained in crushed limestone. The combined sand-limestone shows the lowest water absorption and sorptivity compared with other types of aggregates.

Study on strength characteristics of concrete using M-Sand and coconut fibers

In the current world, concrete has become a very important part of the construction industry and the materials which are used in making concrete have evolved due to better quality of cement and better grade of coarse aggregates. The sand is an important part of concrete. It is mainly procured from natural sources. Thus the grade of sand is not under our control. The methods of removing sand from river beds are causing various environmental issues and river sand is depleting at a faster rate than it is replaced by natural methods. Hence, various replacements for the river sand are being done, one of which is manufactured-sand. It is obtained from various granite quarries. Manufactured-sand or M-sand is slowly replacing the fine aggregate in the concrete as the sand is well graded and gives higher strength of concrete. There are various fibers used for reinforcing concrete which consist mainly of artificial or steel fibers. Some of these fibers are quite costly and sometimes difficult to obtain. So there are many natural fibers which can be used in place of these fibers, one of which is coconut fiber, extracted from the shell of a coconut. Coconut fibers are used in various industries like rope making, coir mattresses etc. Since these fibers are one of the strongest fibers among naturally occuring fibers, they can be used in the concrete mix to increase the resistance in concrete. They are also light weight and easily available and thus can be used in reinforcement of concrete. The studies up till now have tested the use of coconut fibers in normal concrete involving river sand but in this study a particular ratio of M-sand and river sand is used to get the maximum possible strength. Hence, in this project an attempt was made to use M-sand and coconut fiber in concrete. Based on the test results, it can be concluded that combination of M-sand and coconut fibers gave favorable results in strength criteria.

Crushed Sand Grading and Quality Control Along Pu Xuan Highway

Making an investigation on crushed sand along Pu Xuan highway. Stone power content is much more than nature sand. Comparing national standard and department standard, coarse particle larger than 2.36mm and fine particle smaller than 0.15mm are much more than standard. Adjusting partial sieve residue, crushed sand grading can reach standard level. By discarding all of particle larger than 4.75mm and part of ones smaller than 0.15mm, crushed sand grading can reach the second zone standard level. It can be used in concrete for bridge beam and slab.

Injectability of Microfine Cement Grouts into Limestone Sands with Different Gradations: Experimental Investigation and Prediction

One-dimensional injection tests were conducted on dry and dense sand columns with a height of 36.5 cm for the injectability evaluation of cement grouts. Three ordinary cement types were pulverized to obtain fine-grained cements having nominal maximum grain sizes of 40, 20 and 10 μm. Suspensions of these cements with water to cement (W/C) ratios of 1, 2 and 3, by weight, were injected into 54 clean, limestone sands with different gradations. Pulverization of the ordinary cements to produce microfine cements extends the range of groutable sands to “medium-to-fine”. Suspension injectability is improved by increasing cement fineness and suspension W/C ratio or by decreasing apparent viscosity and is controlled by the synthesis of the finer portion (d ≤ d25) of the sand gradation. The outcome of the 131 injectability tests conducted is successfully predicted by available groutability criteria at a rate ranging between 51 and 69%. The “new groutability and filtration criteria” proposed in this study, are adapted to the finer 25% of the sand gradation, have successful predictions for 79% of the cases (10–28% higher than those of the existing groutability criteria) and predict successfully the appearance of filtration in 83% of the available cases. The model developed by performing Binary Logistic Regression analyses of the injection test results is considered appropriate for the prediction of injectability of cement grouts in sands because it exhibits a coefficient of multiple determination equal to 0.84 and provides a rate of successful predictions equal to 78% of the available experimental results.

Secondary Mineral Resources for Refractory Manufacture. Part 1. Silica Technogenic Materials

Aversion is proposed for chemical and mineral classification of technogenic refractory raw material. Secondary mineral resources are considered of essentially silica composition represented by four large-scale technogenic formations.Waste-free technology is developed for processing sub-standard material with preparation of enriched raw material for producing quartzite filler grade ZVK-97, building gravel, and sand. The suitability is established for the fine-grained fraction of silica waste (enrichment tailings) for preparing molding, filter, building materials, and also in a raw material for producing some grades of packaging glass and other materials. The possibility is demonstrated of using regeneration products of exhausted molding mixes for preparing high quality dinas. Microsilica is studied comprehensively, on whose basis promising areas for its utilization are developed.

Lightweight ceramsites prepared by the solid waste of semiconductor and textile dyeing industry

High-efficient recycling of solid waste from the semiconductor or textile dyeing industry has been a challenge since these industrial waste not only brings a heavy burden to enterprises but also seriously affects our ecological environment. Here, a feasible method is proposed to recycle this solid waste by transferring it into high value-added ceramsites. They were prepared by using the third grade sand of cutting silicon (TGSCS) and textile dyeing sludge (TDS) as raw materials and composed mainly of SiO2–Al2O3. Through systematic analysis of the experimental results, it was concluded that the optimized ratios of the TGSCS and the TDS should range from 1:1.5 to 1:3, while the sintering temperature should be around 1150[Formula: see text]C. These lightweight ceramsites can have excellent properties of the cylinder compressive strength of 4.65 MPa and bulk density of 477 kg/m3. The potential expansion mechanism was thought to be related to both TGSCS and TDS as they reacted with Fe2O3 impurity to form CO2/CO gases. This work is to prepare lightweight ceramsites and to recycle solid waste.

Controlling of Moisture in Subgrade Backfilling Sand

Moisture content in the sub grade will be affected by the external water level or rain after the moisture of sub grade reach to the equilibrium. According to the unsaturated flow, two-dimensional finite element method models of sub grade were established. Slope protection and blind drainage was used to study the influence to moisture of sub grade of backfill sand, the results indicate that the combination of slope protection and blind drainage was an optimal method, which can effectively reduce the moisture of sub grade.

Facies analysis and depositional model of the Serravallian-age Neurath Sand, Lower Rhine Basin (W Germany)

AbstractThe up to 60 m thick Neurath Sand (Serravallian, late middle Miocene) is one of several marine sands in the Lower Rhine Basin which were deposited as a result of North Sea transgressive activity in Cenozoic times. The shallow-marine Neurath Sand is well exposed in the Garzweiler open-cast mine, which is located in the centre of the Lower Rhine Basin. Detailed examination of three sediment profiles extending from the underlying Frimmersdorf Seam via the Neurath Sand and through to the overlying Garzweiler Seam, integrating both sedimentological and palaeontological data, has enabled the depositional setting of the area to be reconstructed.Six subenvironments are recognised in the Neurath Sand, commencing with the upper shoreface (1) sediments characterised by glauconite-rich sands and an extensive biota (Ophiomorphaichnosp.). These are associated with the silt-rich sands of a transitional subenvironment (2), containingSkolithos linearis, Planolitesichnosp. andTeichichnusichnosp. These silt-rich sands grade up to the upper shoreface subenvironment (1), which is indicative of an initial regressive trend. The overlying intertidal deposits can be subdivided into a lower breaker zone (3), characterised by ridge-and-runnel systems, and the swash zone (4) where the surge and backwash of waves resulted in the deposition of high-energy laminites. The intertidal deposits were capped by aeolian backshore sediments (5). Extensive root traces present in this latter subenvironment reflect the development of the overlying peatland (i.e. Garzweiler Seam). Within the Garzweiler Seam, restricted sand lenses indicate a lagoonal or estuarine depositional environment (6). Regional correlation with adjacent wells establishes that shallow-marine conditions were widespread across the Lower Rhine Basin in middle Serravallian times. The shoreline profile, characterised by both tidal and wave activity and influenced by fluvial input from the adjacent Rhenish Massif, is indicative of the complexity of the coastal depositional setting within the Lower Rhine Basin.

Development of ultra-high performance concrete with locally available materials

Ultra-High Performance Concrete (UHPC) is an advanced type of concrete that can enhance the durability and resilience of concrete structures. The use of local materials is a fundamental step to save materials and energy and reduce the cost of concrete. In this study, the effect of sand gradation, binder type and content, and curing regimes on concrete’s compressive strength was examined. Results indicated a 90-day strength of 155MPa was achieved with a silica fume content of 5% and without heat curing. A curing regime of 2days at 60°C followed by 3days at 90°C resulted in the highest strength.