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The particle size distribution (PSD) and particle morphology of metal powders undoubtedly affects the quality of parts produced by additive manufacturing (AM). It is, therefore, crucial to accurately know the PSD and morphology of these powders. There exist several measurement techniques for these quantities, but since each method is based on different physical phenomena, which are sensitive to different aspects of a particle's shape and size, it is unclear how the measured PSDs and morphology compare to one another. In this study, five different techniques are used: sieve analysis, dynamic imaging analysis, laser diffraction analysis, X-ray computed tomography (XCT), and scanning electron microscopy. The first three are commonly used in the powder metallurgy field while the last two are laboratory-based tools capable of providing robust size and shape data. Nominally identical samples of stainless-steel powders were produced via riffling, and each technique was employed to measure effectively the same PSD and in some cases the morphology. In this paper, the differences among these measurement techniques are explored by a comparison of the measured results. Besides the random variations of the various measurement processes, the difference in the results is partly due to the fact that the particles are not perfectly spherical and that there are many multi-particles present. Each of these affect the principle of each method differently. Three-dimensional particle morphology and size data collected via XCT is used to provide insight regarding the discrepancies among other sizing and morphology measurement techniques. (Official contribution of the National Institute of Standards and Technology; not subject to copyright in the United States.)

Switchgrass has potential as an energy crop, but problems with handling and flowability hinders its utilization. The primary objective of this study was to investigate the fundamental flow-related physical characteristics of switchgrass particles ground through three hammermill screen sizes of 6.4, 3.2 and 1.6 mm. Physical properties were determined through sieve analysis, density testing, image analysis, angle of repose and fractal analysis. The geometric mean diameter and geometric standard deviation of the ground material decreased with size reduction. Particle size significantly influenced particle and bulk density. Similar conclusions were made for angle of repose; values decreased with size reduction. Shape and surface parameters from image and fractal analyses were not significantly different among particle sizes. Non-spherical, needle-shaped particles were maintained through size reduction. Particle size reduction may slightly improve the flow of ground switchgrass bulk, but will always experience some degree of flow problems in regular storage silos and hoppers.

Particle size is an important parameter in the processing of reinforcement particles utilized as particulate metal matrix composites. These particulate reinforcements provide advantages such as high stiffness, high strength, wear resistance properties, corrosion and thermal resistance to metal matrix composites (MMCs). This work attempts to study the effects of ball milling on the density, microstructure and morphology of fly ash. The milling times were varied as 0 mins, 15 mins, 30 mins, 45 mins, 60 mins and 180 mins. The density of the fly ash samples was measured as 2.44 g/cm3 using Le Châtelier's principle. The microstructural analysis showed a change in morphology with increasing milling time. The SEM micrographs showed an agglomeration of the fly ash particles due to the dry milling conditions. The EDS analysis showed the presence of oxygen, aluminium, silicon and iron as the major elements common to all the fly ash samples at the different milling times. The XRD analysis identified mullite (3Al2O3SiO2), silica (SiO2), alumina (Al2O3), wustite (FeO) and hematite (Fe2O3) as the major phases. The particle size distribution obtained via wet sieve analysis showed that 16.3%, 3.9%, 1.76%, 0.43%, 0.1%, and 0% were retained for the 0mins, 15 mins, 30 mins, 45 mins, 60 mins and 180 mins milled fly ash samples respectively.

Stabilization of soil is nowadays an inevitable process due to the poor quality associated within it and reducing the nature of index and engineering properties of the soil. It has been enhanced with the help of reinforcing the earth. In this study, an experiment has been conducted to study the performance of red soil before and after adding polypropylene. Various geotechnical properties are studied and improvement in the soil properties with different percentages of polypropylene (1%, 2%, 3%). The index properties such as sieve analysis, consistency limit, and compaction characteristics and major engineering properties like shear strength from unconfined compression test and California bearing ratio were found out. The result obtained indicated that reinforcing of polypropylene fiber increases properties of red soil.

Sago pith waste produced in largely during the manufacturing process of sago flour and causes serious environmental pollution. Once SPW is dried, it can be stored and further exploited for its high starch content. SPW has an original moisture content of 90% wet basis but can be dried to 10% wet basis. This study evaluated the effects of the bulk and tapped densities on the moisture content of SPW and used the compressibility index and Hausner ratio to characterize the flow of SPW in a fluidized bed dryer at wet basis. The temperature (50–80 °C) and velocity (1.5–2.1 m/s) of the air supplied into the fluidized bed dryer were considered in terms of the loss of moisture content, drying rate, and fluidization profile of the drying process. The effective moisture diffusivity were estimated to determine the optimum drying condition. The experimental results showed that the drying process took less time and reached a higher drying rate as the air temperature and velocity increased. Increasing the air temperature increased the heat transfer between SPW and dry air and accelerated the movement of moisture to the surface. The air velocity had a less significant effect on the drying process and was more important for fluidization of the SPW. The profile showed a fixed bed during early fluidization, followed by a bubbling state and then turbulent condition. Increasing the air temperature reduced the time for SPW to reach turbulent situation. Increasing the air velocity increased the bubbling fluidization density and accelerated the turbulent fluidization. Based on the effective moisture diffusivity analysis, it showed that the optimum drying process of SPW could be achieved at air velocity of 1.50 m/s with 80 °C of air temperature and at air temperature of 70 °C with 2.10 m/s of air velocity. Meanwhile, dry sieve analysis was performed to obtain the particle size distribution and percentage of fines in SPW with the sieve sizes of 3.35, 2.00, 1.70, 1.00, 0.85, 0.60, and 0.43 mm. Then, SPW was classified and characterized according to each particle size range. Visually, SPW was found to have three categories of particles: sand, gravel, and fibrous wood.

Soil particle size distribution (PSD) is critical for assessing the potential for internal instability of sand–gravel soils, mainly because particle migration in sand–gravel soils owing to seepage forces affects almost all soil hydraulic properties during internal erosion processes. Therefore, a reliable PSD analysis is essential for revealing the mechanism of particle migration and internal instability of sand–gravel soils. At present, however, PSD is commonly calculated by manual interpretation methods and cannot be continuously and nondestructively analyzed during internal erosion processes. Those methods are lacking, however, in that it results in a failure to continuously determine the internal erosion condition. In this paper, a new approach with the ability to continuously predict the PSD changes in sand–gravel mixtures is introduced based on one-dimensional laboratory suffusion tests in a non-destructive nuclear magnetic resonance (NMR) system over a range of suffusion times. The results show that pore expansion and particle migration are an interactive process that controls suffusion development in sand–gravel mixtures. The proposed method is verified through experimental data measured by sieve analysis, and has potential to retrieve PSD information at different suffusion times.

Main objective is to study effect on mechanical properties of M20 grade concrete by varying fineness proportions of fine aggregate in both river sand and M-sand, which is one of the major constituent of concrete. In construction field fineness of fine aggregate being used is IS 4.75 mm sieve is probably used in all cases. The fine aggregate used for casting involves river sand and M-sand. The IS sieve sizes 2.36 mm and 1.18 mm were taken as alternative. The results shows increase in fineness increases the strength of concrete.

Non-segregating ordered powder mixtures constituted by a coarse carrier fraction and finer components are at the basis of dry powders for inhalation pharmaceuticas. The estimation of the loading capacity, i.e. how many fines can be hosted on each carrier particle, is crucial to grant the product quality through a reproducible and affordable manufacturing process. We propose an approach based on the combination of sieve analysis, optical microscopy and powder bed permeability to quantify the loading capacity and understand the fines behavior, the impact of the mixing process was also investigated. We tested the method on model binary mixtures composed only of a coarse lactose carrier and micronized lactose fines as a surrogate of a real active pharmaceutical ingredient. The results provided by the different methods are consistent, the approach proved to be accurate and reproducible. The effect of different mixing parameters and equipment on the loading capacity is also discussed.

Many particulate composites show heterogenous mesoscopic structural behaviour due to a random distribution of irregular shaped particles with different sizes ranging from micro to macro scale. Accurate mesoscale models are required to represent actual geometric properties of such a composite with realistic features. In this paper, a cost-effective simulation framework is presented, which can virtually generate three-dimensional mesostructure models composed of irregulate particles with real characteristics. A MATLAB code is developed based on the Voronoi tessellation method and the splining technique. The hybrid Voronoi-spline algorithm can be programmed to control the shape and size of particles based on the experimental data. The examples demonstrated the proper adjustability of the models in accordance with the sieve analysis and shape parameters such as sphericity and roundness. The generated model as a triangulated geometry surface can be directly exported into computational analysis of materials, which uses other numerical techniques including finite element method.

The physical, hydrological, and physico-chemical properties of horticultural substrates are influenced by particle shape and size. Sieve analysis is the predominate method utilized to characterize the particle size distribution of horticultural substrates. However, the effect of particle length on sieve analysis results have only been speculated. Laser cut particles with eight different length to width (L:W) ratios were sorted by sieves for agitation times ranging from 1 min to 5 min. To quantify the effect of L:W ratio and agitation time, the means (mid-point) and standard deviations of particle distributions were compared. Particles with a 1:1 L:W ratio were the most accurately sorted particles, containing midpoints most similar to true sieve size. As particle length increased, distribution midpoints and standard deviation increased. Elongated particles, 2:1 L:W ratio and greater, may cause the particle size distribution to skew positively. Increasing agitation time influences the probability of a particle and open sieve aperture converging in an orientation which allows it passage and can improve sieve accuracy and precision. By improving the consistency of sieving protocols, the accuracy of sieve analysis could potentially be improved. However, alternative instruments should be evaluated to improve the characterization of horticultural substrates. If, in the future, the characteristics of elongated or complex-shaped particles are desired, it may prove more beneficial to refine engineering practices than rely on sieving to precisely sort and isolate them.

The rapid growth in plastic and demolition wastes generation by municipal and commercial industries is a significant challenge to developed and developing countries. The substitution of traditional construction materials with recycled materials is a sustainable solution which mitigates landfilling concerns and reduces the need for virgin quarry materials. In this research, an evaluation of the geotechnical and geo-environmental properties of Polyethylene terephthalate (PET) plastic waste and its blends, with two major constituents of construction and demolition (C&D) waste materials was undertaken. Recycled concrete aggregate (RCA) and crushed brick (CB) were blended with 3% and 5% of PET, and the geotechnical properties of six PET blends were evaluated in the laboratory. The experimental programme included particle size distribution, particle density, sieve analysis, flakiness index, Los Angeles abrasion, water absorption, modified Proctor compaction, hydraulic conductivity, and California bearing ratio (CBR) tests. In addition, the response of the PET blends under repeated dynamic loading conditions was investigated using repeated load triaxial (RLT) tests. CBR results of all six PET blends were higher than the minimum CBR requirements for usage as a subbase material. The RLT testing results indicated that PET blends with RCA and CB performed satisfactorily at 98% maximum dry density and at their optimum moisture contents under modified Proctor compaction effort. Furthermore, a geo-environmental evaluation of the PET blends was undertaken which consisted of determination of organic matter content, pH value, total/leachate concentration of the recycled materials for a range of contaminant constituents and the results were compared with requirements specified by environmental authorities. Control samples, 3% and 5% PET blends with RCA and CB satisfied the CBR requirements. Similarly, control samples, 3% and 5% PET blends with RCA were found to be satisfactory for RLT requirements for subbase applications.

In the fields of mining, construction, geology, material science and etc., the grain size or grain size distribution emerges as the most important parameter in understanding and controlling of various processes and also in determination of their success. Screening and image analysis are the most frequently used methods for this purpose. In this study, it is aimed to determine particle size distribution of aggregates by using point cloud data obtained by terrestrial laser scanning method and developed algorithm. For this purpose, aggregate mixtures with different particle sizes were prepared in the laboratory, then the surfaces of these mixtures were scanned with a laser scanner to obtain point cloud data. The point cloud data were analyzed with the developed algorithm and the particle size distribution curves of the mixtures were obtained. These curves were compared with those obtained by sieve analysis and found to be very compatible with each other.

Microplastics are abundant in both aquatic and terrestrial environments. While they have received much recent attention because of their effects on ecosystems, their true impact on natural environments remains difficult to assess because of the problems associated with processing them in the laboratory. In this study, we designed and implemented a new, vacuum-based method of separating different sizes of low-density polyethylene films. Using multiple sieve sizes, we achieved consistent recovery of the desired size fractions using this method. The vacuum suction (VS) system consisted of two differently sized cylindrical sieves of 500 μm (or 200 μm) and 65 μm, allowing film samples between 65 and –500 μm and 65–200 μm to be collected. The VS systems successfully separated microplastic film samples into small area ranges of 0.015–0.065 mm2, and the film areas showed different distributions for each sample from the different VS systems. This system provided an easy, rapid, and low-labor means of processing different sizes of microplastics via an innovative method. Further research into the effects of microplastics on natural environments is critically needed, and the laboratory separation of different size fractions of microplastics facilitates such endeavors.

The gradation and mechanical properties of aggregates impressively affect the load carrying capacity and rutting resistance of asphalt mixtures. They are able to provide some fundamental parameters that are linked to mixture performance. In order to accurately detect critical controlled sizes and obtain more fundamental parameters that can characterize load carrying capacity and rutting resistance of asphalt mixtures, this paper aims to develop a mechanics-based approach to evaluate aggregate gradation, which contains the theoretical packing analysis and discrete element simulation. An extended theoretical morphology framework is developed by checking the local and global interlock of graded aggregates in the theoretical packing analysis. The sieve size range of primary structure which has an interactive interlock can be determined in the local interlock check model. The relationship between the transferred force and the induced force is proposed in the densest and loosest packing arrangements, respectively. The morphological parameters of disruption factor and weighted average size for the global scale are also proposed in theoretical packing analysis. Then the discrete element method is used to validate the theoretical framework. The advanced gradation input algorithm procedure is established in the discrete element simulation to simulate the compression test of graded aggregates. The mechanical parameters of contact force, contact points and stress–strain curves are extracted from the simulation results. The results show that the discrete element method can validate the theoretical framework and output the performance related parameters. The contact force analysis shows that the aggregates retaining on sieve sizes of 2.36 and 4.75 mm provide more than 50% contribution to resist load, and the aggregates retaining on sieve sizes of 1.18, 0.6 and 0.3 mm provide more than 50% contribution to stabilize the structure. The coordination number analysis suggests that the gradation with more fine aggregates might lead to a greater number of voids but smaller air-void size when the asphalt content and porosity remain constant. The stress–strain curve analysis shows that the modulus and secondary strain are highly related to the rutting performance of an asphalt mixture.

Mixtures of a fine sand with platy shell fragments have been tested under drained monotonic and high-cyclic loading. The content (0 to 40 %) and the size of the platy shell particles in the mixtures were varied. Comparative tests have been also performed on a mixture containing 40 % coarse sand and gravel particles instead of the shells. In the cyclic tests different stress amplitudes, initial relative densities and average stresses have been tested on the various mixtures. The strain accumulation rates were found to increase with growing content of shell particles. This can be primarily attributed to the more well-graded grain size distribution curves of the sand-shell mixtures. Particle breakage effects were almost absent in the cyclic tests as demonstrated by sieve analysis. Dependencies between the parameters of a high-cycle accumulation (HCA) model and the content of shell particles are analyzed. Amongst others, an extraordinary low dependence of the strain accumulation rate on strain amplitude (parameter C ampl 1 ) has been observed for larger amounts of shell particles in the mixtures.

In this study, the effect of coal dust in variable sizes and weight on photovoltaic (PV) modules' performance has been examined under laboratory conditions. Experimental studies have been performed under Standard Test Conditions (STC: Radiance: 1000 W/m2; Cell temperature: 25 °C; Sun Spectrum: AM 1.5) for monocrystalline silicon (m-Si) and polycrystalline silicon (p-Si) PV modules. By using sieve analysis, the particle sizes of coal dust have been divided into six groups which are in µm size and as follows: (−38), (+38/−53), (+53/−75), (+75/−106), (+106/−250), (+250/−500). Artificial pollution has been created by uniformly distributing coal dust of certain size and weight onto PV modules. Three different weights of coal dust (5 g, 10 g and 15 g) have been employed for every single size of coal dust. In order to investigate the effect of any particle size and any weight of coal, the performance of PV modules has been investigated by measuring voltage, current and power. The data set consisting of electrical parameters has been used to develop a model by using Adaptive Neuro-Fuzzy Inference System (ANFIS). Comparison of experimental and ANFIS results have been given by calculating of Root Mean Square Error (RMSE) and coefficient of determination (R2). The performance indices have been calculated as RMSE = 0.18719 and R2 = 0.99803 for m-Si, RMSE = 0.87098 and R2 = 0.99714 for p-Si PV modules. According to the results, for a given particle size and weight, the ANFIS model is quite successful in power estimation for PV modules.

A lot of innovative methods are being explored and a few of them are successfully executed in construction activities. A strong road network is also a fundamental prerequisite for the complete growth of productive regions. The strength and quality of the pavements are greatly affected by sub-grades and embankments. Though they're nice for these purposes, they do not seem to be suitable for laying roads. Suitable building techniques and dynamic design approaches are to be implemented on such soils. The soil was first stabilized with Prosopis Julifoira Ash at a ratio of 2, 4, 6, and 8 percent during this work. Sieve analysis, Specific gravity test, Atterberg limits, Compaction test, CBR test, and Permeability test, Unconfined Compression test were carried out. The optimum proportion of JF Ash was found out to be 8% from the CBR results. The optimum proportion of Prosopis Julifora ash with soil was found out to be 5%. The optimum proportion of Prosopis Julifora Ash mix was used to design the pavement as per IRC37 -2001 Thus we aim to improve the stability or bearing capacity of the soil by the addition of suitable stabilizing agents. Soil stabilization refers to the physical, physicochemical treatment which improves the engineering properties of soil. IRC 37-2001 was used to designing the flexible pavement.

This work reports fundamental combustion characteristics of high ash (∼ 18 %), high plastic (30–35 %) content refuse derived fuel (RDF) pellets produced currently in India. Single particle and packed bed studies of RDF were carried out to quantify RDF combustion times and RDF ash fusion behavior, respectively. Single particle studies concluded that RDF has glowing time to flaming time ratio of ∼ 3.5, which was similar to that of biomass and four times lower than that of coal. It was also observed that unlike biomass, upon heating, RDF particle showed a unique 5.6 to 10.3 % swelling behavior due to the melting of plastic. Packed bed experiments at different air mass flux on RDF pellets concluded that apart from air mass flux, ash content plays a decisive role on rate of flame propagation. The high plastic content of fuel increased ash fusion tendency inside the packed bed. Packed bed studies suggested maximum superficial velocity of ≤ 0.03 m s−1 to avoid clinker formation. Sieve analysis of RDF ash collected from packed bed studies reported soft ash at a lower air mass flux and bigger lumps of fused ash at higher air mass flux. Clinkers obtained at different air mass flux 0.02, 0.07, 0.13 kg m−2 s−1 were 1 %, 8 % and 11 % of the feed, respectively.

The aim of this work is to obtain a balanced commercial virgin olive oil (VOO) using response surface methodology at an industrial level under continuous working conditions. Thus, a factorial design was developed with three factors: sieve size of the hammer mill, temperature, and malaxing time. Forty different responses were modulated, including extraction efficiency, but with special attention to phenolic and volatile compounds because they are responsible for the taste and aroma of VOO. The conditions for malaxing were 22 and 32 °C for 60 and 120 min using 5 and 6 mm sieve sizes. After modeling the responses, the highest extraction efficiency was obtained at 32 °C and 120 min; similar conditions were necessary to obtain the maximum contents of chlorophyll, carotenoid, and phenolic compounds, but the maximum content of volatile compounds was obtained at 22 °C. Therefore, it has also realized a combined optimization of total phenolics and total volatiles.

Agglomeration of pellets in fluidized bed coating processes is an undesirable phenomenon that affects the yield and quality of the product. In scope of PAT guidance, we present a system that utilizes visual imaging for in-line monitoring of the agglomeration degree. Seven pilot-scale Wurster coating processes were executed under various process conditions, providing a wide spectrum of process outcomes. Images of pellets were acquired during the coating processes in a contactless manner through an observation window of the coating apparatus. Efficient image analysis methods were developed for automatic recognition of discrete pellets and agglomerates in the acquired images. In-line obtained agglomeration degree trends revealed the agglomeration dynamics in distinct phases of the coating processes. We compared the in-line estimated agglomeration degree in the end point of each process to the results obtained by the off-line sieve analysis reference method. A strong positive correlation was obtained (coefficient of determination R2=0.99), confirming the feasibility of the approach. The in-line estimated agglomeration degree enables early detection of agglomeration and provides means for timely interventions to retain it in an acceptable range.

Classical methods (measuring the pressure drop across a bed for different flowrates of air through the bed) were used to determine the superficial velocity for minimum fluidisation, Umf, of sieved particles of alumina. The particles were characterised optically using an instrument (Morphologi G3, Malvern Instruments), which, from pixelated, enlarged photographs, measured the particles’ mean diameter, dp, to be 0.48 ± 0.04 mm and their sphericity, ϕ, to be 0.77 ± 0.09. Values of Umf were measured for the temperature in the electrically heated bed varying from 14 to 920 °C. The results were analysed using Ergun’s equation; one outcome was that the voidage, emf, in an incipiently fluidised bed was found to be related to the particles’ sphericity by: ( 1 − e m f ) / ϕ 2 e m f 3 = 12.2 ± 0.4. The measured Umf were significantly larger than the values predicted by Wen and Yu’s equation, if the mean diameter of the particles was taken, as recommended, to be the geometric mean of the upper and lower sieve sizes, used when preparing the particles. Alternatively, the measured values of Umf were over-predicted by Wen and Yu’s equation, when using the optically measured mean size of the particles. The best predictions of Umf were made by using the optically measured mean values of both dp and ϕ, together with Ergun’s equation and the above equation coupling emf and ϕ. Such a procedure is proposed for estimating Umf in general. No evidence was found for emf varying with temperature.

Granular media filtration is one of the most important and commonly used operations in water treatment and is also widely used for advanced wastewater treatment. Successful filter design requires a correct specification of backwash rates for filter cleaning. Significant progress has been made in recent years towards a capability of accurate predictions of backwash expansion of uniform (sieved) fractions of nonporous and porous nonspherical media. Graded filter media, however, have not been studied in a systematic and satisfactory way so far. Current design calculations consider a bed with a size gradation to consist of several layers of approximately uniform size according to the sieve analysis data, and the expansion of each layer is separately calculated. The total expansion is calculated by adding the expansions of all the layers. The present work evaluates the accuracy of this approach and a number of alternative calculation methods by carrying out fluidization experiments with actual filter media including silica sand, garnet sand, perlite, crushed recycled glass, activated carbon, anthracite coal, and zeolite.

A series of large-scale direct shear tests were conducted to investigate the behavior of unreinforced and geogrid-reinforced ballast at different rates of shearing. Fresh granite ballast with an average particle size ( D 50 ) of 42 mm and five geogrids having different aperture shapes and sizes was used in this study. Tests were performed at different normal stresses ( σ n ) ranging from 35 kPa to 140 kPa and at different rates of shearing ( S r ) ranging from 2.5 to 10.0 mm/min. The laboratory test results revealed that the shear strength of ballast was significantly influenced by the rate of shearing. The internal friction angle of ballast ( φ ) was found to decrease from 66.5° to 58° when the shearing rate ( S r ) was increased from 2.5 to 10.0 mm/min. It is further observed that the interface shear strength has improved significantly when the ballast was reinforced with geogrids. The interface efficiency factor ( α ), defined as the ratio of the shear strength of the interface to the internal shear strength of ballast, varies from 0.83 to 1.06. The sieve analysis of samples after the testing reveals that a significant amount of particle breakage occurs during shearing. The value of breakage, evaluated in terms of Marsal's breakage index ( B g ), increases from 5.12 to 13.24% with an increase in shearing rates from 2.5 to 10.0 mm/min. Moreover, the influence of aperture shape and size of geogrid on the behavior of ballast-geogrid interfaces was also examined in this study.

Deep-fried battered and breaded coatings provide foods with texture, flavour, reduced moisture loss and oil uptake. The physical characteristics of deep-fried batter and breadcrumb coatings was investigated for deep-fried prawns. Previous data on the effect of breadcrumb size on the microstructure of the coating is limited, therefore breadcrumbs were divided using the following sieve sizes and then applied to the coating in order to investigate the effect of breadcrumb size on the physical and mechanical properties: 4.0 mm, 2.8 mm, 2.0 mm, 1.4 mm, 1.0 mm, 710 μm, 500 μm, 355 μm. After frying, internal morphology was studied using X-ray microCT showing that the total porosity of coatings decreases with breadcrumb size whilst pore size distribution and structure thickness distribution increased with breadcrumb size. As crispness is a fundamental sensorial property of deep-fried battered products, crispness was evaluated by uniaxial compression to acquire mechanical and acoustical measurements simultaneously. Results showed decreasing breadcrumb size reduced the number of multiple failures, reduced jagged appearance of the force profile was observed, reduced maximum compression force and acoustic emission, which has been used as a representative of crispness. This study provides evidence of the importance of breadcrumb size in deep-fried battered and breaded formulations.

This paper introduces a soil distortion factor (SDF) to establish a relationship between particle size compositions of soil and irradiance received by a tilted soiled solar panel. Particle size composition of five soil samples was determined using sieve analysis and artificial soiling experiments were performed to measure open circuit voltage (Voc) and short circuit current (Ish) to calculate power output of soiled panel. The power obtained from experimental data was compared with the ideal power output of a clean panel to quantify SDF at three regions of tilt angle. Further, SDF is expressed in terms of particle size composition of soil using regression analysis to calculate irradiance loss. It was observed that the irradiance loss varies with tilt angle and particle composition of soil. Soils rich in particles with 150 µm diameter (Soil 1) and 300 µm diameter (Soil 3) cause irradiance losses up to 6% and 21% while Soil 2 with high composition of 75 µm particle size leads to maximum losses of 10%. Soil 4 with 300 µm particles as its major composition causes losses as high as 22% in the same tilt angle range. Soil 5 having the highest composition of less than 75 µm size particles causes 12% irradiance loss in 0–60° tilt angle region.

Natural fibre (NF) is considered as the most available resource that exists in nature. Date palm trees (DPT) accounts for more than 2.8 million tons of waste annually, making it the most abundant agricultural biomass waste in the MENA region. Date palm fibre (DPF) extracted from DPT possesses great mechanical and physical characteristics which make them superior to other NFs in the MENA region. This study investigates the effect of DPF diameter size and loading content on both the mechanical and physical properties of DPF reinforced recycled polyvinyl chloride (RPVC) composite. The composites are developed using melt-mixing technique which is followed by compression moulding. The influence of the mechanical properties is investigated by evaluating the impact strength, tensile strength and flexural strength. Meanwhile the sieve analysis, thickness swelling (TS), moisture content (MC) and water absorption (WA) characteristics are evaluated. Composite microstructures are examined using optical microscopy to investigate the interfacial bonding between DPF and RPVC matrix. Results showed that at 40 wt% DPF, the TS, MC and WA were the highest demonstrating an increase of 1.57%, 1.76%, and 10.80%, respectively. The flexural strength, tensile strength and impact strength decreased as the loading content increased showing maximum reduction at 40 wt% loading, varying depending on DPF geometry. Although the results demonstrated a decrease in mechanical properties and an increase in physical properties as DPF loading increased depending on DPF geometry, the results indicate a great potential that the developed technologies could be industrialised under the waste management scheme for non-structural applications.

The present work describes the synthesis, optimization, and evaluation of synthesized hydroxyapatite (HAp) from catfish bones (CB). This is with a view to achieving optimum processing conditions and sustainable pedagogical approaches for the preparation of hydroxyapatite scaffolds for tissue engineering. The catfish bones derived hydroxyapatite were prepared through conventional sintering, and low-cold compaction pressure (1 MPa), while the Box-Behnken statistical design tool was used in determining the optimum preparation conditions. Analytical studies were performed on the synthesized HAp to elucidate the physico-chemical and mechanical characteristics of the designed formulation. Three parameters; heating temperatures, holding times, and, sieve sizes were adopted to establish a significant correlation on the physico-mechanical characteristics of the fabricated HAp scaffolds. From the design of experiment (DOE), heating temperature proved to have the most significant effect on the material's mechanical and physical properties when compared to holding times and sieve sizes, with compressive strength (13 MPa), density 1.856 g/cm3 and fracture toughness (2.407 MPa m1/2) observed to be the most improved properties in that order. The physico-mechanical properties of the hydroxyapatite scaffolds reached an optimum at 900 °C, 2 h 22 min holding time, and at a particle size of 100 μm. X-ray diffraction and Fourier transform infra-red studies showed that at every experimental run, optimum run (R6) inclusive, hydroxyapatite with remarkable purity was formed. This study, therefore, illustrates the optimum process for the synthesis of catfish bones derived hydroxyapatite revealing the most significant interactions responsible for achieving clinically useful hydroxyapatite scaffolds with a computational pedagogical approach that is useful for innovations in bioengineering education.

Dynamic modulus (DM)—an important stiffness property and a basic input parameter in the design of flexible pavements—is often obtained through expensive, laborious, and time-taking laboratory tests, which can be subjected to human error as well. Predictive models are, therefore, developed in lieu of laboratory testing, enabling the estimation of DM values with some degree of error. Focussing on minimising this error in predicting the DM of asphalt concrete (AC) mixtures, this study proposes an eXtreme Gradient Boosting (XGBoost) approach for modelling DM. Sixteen AC mixtures are prepared in laboratory and tested for DM at different testing temperatures and loading frequencies. The data obtained from the laboratory test are divided into three categories: testing conditions, mix volumetric properties, and gradation, which served as the input to the XGBoost model. More specifically, testing conditions include four testing temperatures (4.4, 21.1, 37.8, and 54.4 °C) and six loading frequencies (25, 10, 5, 1, 0.5, and 1 Hz), mix volumetric properties entail optimum bitumen content, air voids, voids filled with aggregate and asphalt, stability and flow of a mix, binder type, and type of layer, gradation parameters consist of per cent passing of different sieve sizes. Several goodness-of-fit measures are employed combined with k-fold validation technique to robustly evaluate the performance of the developed model. Furthermore, the XGBoost model is compared with some well-known regression-based models as well as other machine learning approaches. The comparison analysis reveals that the XGBoost model outperforms its competing models from the literature by showing a higher degree of accuracy in predicting the observed DM values. Moreover, to further demonstrate the efficacy of the proposed XGBoost model, its transferability is tested for a completely new dataset, and the findings suggest that the model is able to capture the difference in mix properties and preparation type of the new dataset with a reasonable accuracy. In addition, the XGBoost model exhibits a superior performance in transferability analysis compared with its competing models. The findings of this study advocate the use of XGBoost approach for predicting DM values as well as in the design of flexible pavements in future studies.

A great deal of triaxial tests were conducted under various influence factors on the Silica sand No.5 with the purpose of investigating the characteristics of particle breakage. Particle breakage was measured by sieve analysis conducted at the different axial strain level after the tests to obtain relevant grain size distribution curves which were quantified by relative breakage. It was found that the particle breakage in relative breakage increases with increasing axial strain and confining pressure. Particle breakage was also caused during consolidation. Denser sample was revealed to cause more particle breakage. Initial stress anisotropy was found to result in more particle breakage during anisotropic consolidation than that during isotropic consolidation but during shearing the higher confining pressure resulted in more particle breakage than the initial stress anisotropy with a relatively lower confining pressure. Particle breakage was found to increase in up convexity with increasing cycle number of cyclic loading but in up concavity with increasing additional axial strain. A hyperbolic model was proposed to correlate the particle breakage in relative breakage with the plastic work per unit volume for the monotonic and cyclic triaxial tests.

The success of computational materials science models for cement and concrete, at the micrometer-to-millimeter scale, is based on careful characterization of the two main starting materials – cement and aggregates. Concrete is a complex material, and models based on over-simplified chemical, geometrical, and topological assumptions have limits on the behavior they can realistically simulate. In this paper, a sample of Ottawa sand was carefully characterized, since this material is used in laboratories all around North America as the specified sand for many standard tests, including what is possibly the most highly-used ASTM test of all in the field of cement-based materials, C-109, the mortar cube strength test. Particle shape and size distributions were acquired via a combination of X-ray tomography, spherical harmonic analysis, sieve analysis, microscopy and image analysis, and laser diffraction. Quantitative X-ray diffraction showed that the Ottawa sand used was very pure α−quartz with 1% amorphous content. Elastic moduli information at the particle level was obtained via instrumented nanoindentation. Polarized light microscopy showed that the particles that were indented were single crystals. Results for the Young's modulus, E, of Ottawa sand were E = 110 GPa ± 5 GPa (assumed Poisson's ratio of 0.08), in agreement with other nanoindentation results for Ottawa sand in the literature but more than one standard deviation larger than the results obtained from isotropic averages of the elastic moduli tensor of α−quartz, measured by ultrasonic and Brillouin scattering techniques and averaged in various ways. This kind of disagreement has been seen for other minerals as well as α−quartz, and indicates that nanoindentation measurement of elastic moduli for particulate minerals used in cement and concrete and other applications must be used with some care. This characterization procedure can now be confidently employed for any class of sand or gravel particle that is desired to be used in a three-dimensional mortar or concrete model.

Understanding the behaviour of fluid flow through packed ore/rock beds is essential for estimating metal extraction from low-grade ores via dump leaching as well as the release of toxic elements from mine waste rocks. One fundamental factor that determines the flow behaviour in ore/rock beds is particle size distribution. Given the limitations presented by the traditional sieve analysis, we applied aerial imagery to investigate the particle size distribution in ore piles. Using dump leaching as an example, we analyzed the aerial images of a dump leach pad acquired by a camera installed on a drone while the leach pad was under construction. The image analysis results showed that the dump leach pad contained an extremely wide range of particle sizes. A spatial segregation of fine and coarse particles was observed. The widely used P80 was deemed to be questionable to represent particle size distribution in dump leach pads. The Sauter mean diameter (d32) and the dump permeability were found to increase with depth. The technical method described in this study provides a more convenient and reliable tool for particle size distribution analysis, thereby facilitating future studies that will enhance understanding of metal extraction from low grade ores in leaching operations as well as the potential release of pollutants from waste rock piles.

Particle size distribution of coarse aggregates through mechanical sieving gives results in terms of cumulative mass percent. But digital image processing generated size distribution of particles, while being fast and accurate, is often expressed in terms of area function or number of particles. In this paper, a mass model is developed which converts the image obtained size distribution to mass-wise distribution, making it readily comparable to mechanical sieving data. The concept of weight/particle ratio is introduced for mass reconstruction from 2D images of particle aggregates. Using this mass model, the effects of several particle shape parameters (such as major axis, minor axis, and equivalent diameter) on sieve-size of the particles is studied. It is shown that the sieve-size of a particle strongly depend upon the shape parameters, 91% of its variation being explained by major axis, minor axis, bounding box length and equivalent diameter. Furthermore, minor axis gives an overall accurate estimate of particle sieve-size, error in mean size (D-50) being just 0.4%. However, sieve-size of smaller particles (20 mm) are highly correlated to their equivalent diameters. Multiple linear regression analysis has been used to generate overall mass-wise particle size distribution, considering the influences of all these shape parameters on particle sieve-size. Multiple linear regression generated overall mass-wise particle size distribution shows a strong correlation with sieve generated data. The adjusted R-square value of the regression analysis is found to be 99 percent (w.r.t cumulative frequency). The method proposed in this paper provides a time-efficient way of producing accurate (up to 99%) mass-wise PSD using digital image processing and it can be used effectively to replace the mechanical sieving. Keywords: Particle size distribution, Image analysis, Particle shape parameters, Weight/particle ratio, Sieve analysis

International audience; Cocoa powders are highly subjected to caking, a phenomenon of solid particles agglomeration that impairs powder functionalities such as rehydration and flowing properties. This study aimed at identifying the main caking mechanisms occurring during storage of cocoa powders, according to their fat content and water activity, as well as storage temperature. The formation of caked powder was monitored at macroscopic scale by sieve analysis, showing that caking was significant only for fatty powders at 40 degrees C, in agreement with a caking mechanism controlled by fat melting. The similarity of results obtained at 0.2 and 0.7 water activity indicated that the humidity caking mechanism was not significant for these powders. Observations performed by TEM' evidenced the formation of fat bridges, confirming the occurrence of the fat melting mechanism. Then, solvent extraction techniques designed to quantify fat fractions permitted to highlight that storage caused the conversion of encapsulated fat into free fat. At temperatures sufficient to melt cocoa fat (40 degrees C), this newly formed free fat migrates toward cocoa particle surface, enhancing its fat coverage, hence making cocoa particle sticky and prone to cake. Finally, XPS analysis of the extreme surface of cocoa powders confirmed that two conditions should be met to trigger significant cocoa powder caking: high fat content and elevated storage temperature.

Recently, narrow particle size distributions, as measured by sieve analysis, of crushed waste glass were used as a replacement for Portland cement in concrete. Their chemical reactivity was successfully studied as a function of this measure of particle size. Differences between sieve analysis and laser diffraction measures of particle size prompted this current re-analysis. Extremely careful sieving was used to divide the crushed waste glass particles into 0–25 μm, 25–38 μm, and 63–75 μm sieve size ranges, but laser diffraction did not agree with these particle size cutoffs. We use these same materials to try and understand the discrepancies between particle size as measured by laser diffraction and sieve analysis by using X-ray computed tomography followed by spherical harmonic analysis to measure the three-dimensional particle shape and size, as well as the length ( L ), width ( W ), and thickness ( T ) of each particle. We show how laser diffraction and X-ray CT results, along with sieve analyses, can be quantitatively related for these crushed waste glass particles in the approximate size ranges considered. In contrast to previous speculation, the particle width W does not have to correspond closely to the sieve opening – the correspondence depends on overall particle shape. In addition, we demonstrate how many particles are needed to analyze in order to achieve stable averages and distributions of the L / W , W / T , and L / T aspect ratios, which approximately define particle shape. These results have implications for how particle size is measured and interpreted in the cement and concrete and other industries.

A quantitative analysis of variations in granule microstructure based upon changes in primary particle size and bed preparation is presented. The granule microstructures are obtained using X-Ray Computed Tomography (XRCT). An algorithm is developed to measure the number and size of macro-voids (pore space with volume equivalent size greater than or equal to 30 μm or 3 times the primary particle size). Four size fractions of alumina, ranging in primary particle size from 0.5 μm to 108 μm, are sieved using three different sieve sizes to create static powder beds from which single-droplet granules are produced. The analysis shows that large macro-voids exist in ultra-fine powders (0.1–10 μm). The macro-voids take up to 7% of the granule volume and the largest macro-voids are 200–700 μm in volume equivalent size. Changing the sieve preparation changes the size and total volume of macro-voids. In contrast, there are very few macro-voids in granules formed from coarser powders. This study shows that micron sized powders have the opportunity to form complex structures during granulation and that the handling history of the materials should receive greater scrutiny than it currently gets.

The success of the pellet industry depends on internal and external factors, comprising pellet quality, pellet production parameters and market variables. This study investigated the pellet production process from the raw material properties to the economic production parameters in order to quantify the feasibility of a new production concept. The proposed concept includes the sieving of the wet feedstock and successive selective drying of the fine fraction, while the coarse fraction is not dried. The impact of this energy saving measure is evaluated in terms of pellet quality, combustion emissions, and production / transport costs and energy consumption. Three sieve sizes were investigated (1.4 mm, 2.0 mm, 2.8 mm). The feedstock was separated and the fine and coarse fraction were equilibrated at 12 and 24% water content, respectively and mixed again for pelletization in a semi-industrial ring dye press. The pellets showed an improved durability and a higher water content, which had both positive and negative impacts on the combustion emissions. The bulk density decreased, which affected the transport parameters negatively. The economic benefit for medium and large scale production was high, mainly depending on the feedstock water content and the thermal efficiency of the dryer. The 2.0 mm sieve caused the best combination of improved durability, reduced emissions, increasing transport costs and thermal energy savings. A post-press reduction of the pellet water content can further improve the pellet quality and reduce combustion emissions, while the process of wet sieving has to be evaluated on industrial scale.

The processes of transportation of bulk materials from silos and hoppers are significant in various industrial applications because of their influences on material characteristics and working parameters of the production process. In this paper, a rotating valve feeder, with eight vanes was investigated for transport action of bulk materials, such as wheat, maize and rice, which were ground, using the sieve sizes of 1, 3 and 5 mm. The rotating valve feeders under investigation have proven to be useful in transportation processes despite their construction simplicity. All investigations were done experimentally and numerically, using coupled Discrete Element Method (DEM) and Computational Fluid Dynamics calculation (CFD). The influences of different types of bulk materials and its particle size, on the performances of the rotating valve feeder during material transport were explored. The artificial neural network was developed (in the form of a multi-layer perceptron model) in order to optimize the granular flow of the bulk material, showing the high prediction capability of bulk density, dosing time and granular material flow, with the coefficient of determination equal to 0.999 during the training period. The decreasing of the sieve opening diameter caused the decrease in bulk density of the ground material, but statistically significant only for rice, as seen from the experiments and the results of the neural network model. The 5 mm sieve ensured the material with the highest flowability, significantly increasing the granular flow and decreasing the dosing time. The granular particles were modelled as the spheres in the DEM/CFD simulation, with a small-sized triangular surfaces. The DEM/CFD prediction of the mass transport for rice, wheat and maize was quite adequate, obtaining the coefficient of determination being 0.997; 0.998 and 0.849, respectively.

The resilient moduli (Mr) of the unbound layers and subgrade (SG) soils play a major role in estimating the pavement responses and analyses for mechanistic-empirical (M−E) pavement design. Most of the analysis procedures require a single representative Mr value for each unbound layer. However, estimating one representative values for each unbound layer is difficult as it depends on the state of the stresses within the layer. In this study, the stepwise mechanistic analysis approach is used for determining representative Mr values for the unbound materials typically used in Nevada. The Nevada Department of Transportation (NDOT) uses mainly three types of unbound material in the pavement structure; crushed aggregate base (CAB), borrow material, and SG soils. The unbound materials were sampled from multiple locations throughout Nevada District 1 and evaluated through several laboratory tests, which include sieve analysis, moisture-density relationships, and resilient modulus. The resilient modulus values for unbound material at multiple states of stresses were measured in accordance with AASHTO T307. The measured resilient modulus values were fitted to multiple constitutive models to assess the suitability of the models. The CAB and borrow materials fit the theta model very well while the SG soils fits the Uzman model and universal model. The ILLI-PAVE 2005 finite element (FE) program was employed for computing stresses as well as deflection basins in typical conventional flexible pavements under a representative tire loading. The calculated deflection basin was used for estimating the Mr values of the unbound layers using MODULUS 6.1 software.

Millions of tons of iron ore tailings (IOT); a by-product of iron ore processing, are disposed of every year in landfills, quarries, rivers, oceans among others thereby posing environmental problems. The major aim of this study is to evaluate IOT as replacement for river sand in concrete and compare with the result of conventional concrete. Concrete mixtures containing 25%, 50%, 75% and 100% IOT as river sand replacement were prepared with 0.5 water-to-cement ratio (W/C). Compressive and splitting tensile strengths, modulus of elasticity and durability tests (drying-shrinkage, water absorption, chloride penetration and carbonation effects) were conducted on concrete containing IOT. A statistical fitted linear regression analysis was performed on compressive strength to evaluate the significant level of concretes containing IOT. According to British standard, sieve analysis results indicated that IOT were of medium grade quality. Test results indicated that the concrete workability was reduced with IOT while all other strength and modulus of elasticity data were consistently higher than conventional concrete at all levels of replacement. It is recommended that IOT should be used in concrete as sand replacement to minimize environmental problems, cost and natural resources depletion.

In terms of volume, the ornamental stone extraction industry represents a great waste source. For example, in the marble industry, waste can represent as much as 80–90% of the total extracted soil and stone. In order to use the material resulting from stone cutting, three concrete families were produced to be tested for their durability capacity: the first one contains no superplasticizer, the second one a current plasticizer made with a mixture of organic polymers (SP1) and the third a high-performance superplasticizer, made with a combination of modified polycarboxylates in an aqueous solution (SP2). In each concrete family, four substitution ratios were used representing, by cement volume, 0%, 5%, 10% and 20% of marble sludge. During the experimental campaign, the aggregates were characterized in terms of water absorption and particle density, size grading, loose bulk density and voids content, Los Angeles wear, and shape index. The tests performed to characterize the marble sludge were sieve analysis, Blaine’s specific surface, particles density and mineralogical and chemical compositions. The mixes produced were characterized in terms of workability and bulk density in the fresh state. In the hardened state, compressive strength, water absorption by capillarity and immersion, carbonation, chloride penetration and shrinkage were assessed. This research showed that the durability characteristics of concrete get worse as cement content increases and marble sludge content increases. However, for the 5% and 10% incorporation ratios, these losses were insignificant. Superplasticizers’ incorporation was beneficial to concrete’s performance. In particular, the high-performance superplasticizer led to results in the concrete with less 20% cement content similar to those of the reference concrete without admixtures.

Unlike ductile behaviour under static loads, a reinforced concrete structure can respond in a brittle manner with highly localised damage like concrete spalling, cratering and reinforcement rupturing under close-in or contact explosions. High speed fragmentation resulting from concrete spall may cause severe casualties and injuries. It is therefore important to have a better understanding of the concrete spall phenomena and fragments distribution. In the present study, contact explosion tests were carried out on concrete slabs to observe the concrete crater and spall damage. Seven slabs including two control specimens made of normal strength concrete (NRC) and five ultra-high performance concrete (UHPC) slabs are tested. The superior blast resistance capacity of UHPC slabs is verified through comparison against NRC slabs. The influence of longitudinal reinforcement spacing and slab depth on the spall resistance of UHPC slabs is investigated. Predictions through available empirical methods are made and compared with the test observations. The accuracy of these empirical methods is discussed. All fragments resulting from the contact blast tests are collected and analysed through sieve analysis. It is found that Weibull distribution can be used to model the fragments size distribution of NRC slabs while Log-normal distribution better models the fragments size distribution of UHPC slabs.

This paper presents a new computational tool called SANDY© which calculates the sediment size distribution and its textural parameters from a sieved sediment sample using Matlab®. The tool has been developed for professionals involved in the study of sediment transport along coastal margins, estuaries, rivers and desert dunes. The algorithm uses several types of statistical analyses to obtain the main textural characteristics of the sediment sample (D 50 , mean, sorting, skewness and kurtosis). SANDY© includes the method of moments (geometric, arithmetic and logarithmic approaches) and graphical methods (geometric, arithmetic and mixed approaches). In addition, it provides graphs of the sediment size distribution and its classification. The computational tool automatically exports all the graphs as enhanced metafile images and the final report is also exported as a plain text file. Parameters related to bed roughness such as Nikuradse and roughness length are also computed. Theoretical depositional environments are established by a discriminant function analysis. Using the uniformity coefficient the hydraulic conductivity of the sand as well as the porosity and void ratio of the sediment sample are obtained. The maximum relative density related to sand compaction is also computed. The Matlab® routine can compute one or several samples. SANDY© is a useful tool for estimating the sediment textural parameters which are the basis for studies of sediment transport.

This paper introduces a model that quantifies the relationship between power output, incident irradiance and soil particle size composition of soiled photovoltaic panels. Soil samples used in artificial soiling experiments were collected from Shekhawati region in India and their relative percentage of standard particle sizes is determined from sieve analysis. A non-linear relationship between irradiance and power is obtained using regression analysis showing the effect of particle size composition present on the panel. Further, the tilt angle for maximum power extraction is determined for each soiled panel and the deviation from the optimum tilt angle of a clean panel is observed. It is concluded that, when the soil present on the panel is rich in the particles with diameter (75 μm and below), the deviation from the tilt angle of a clean panel is 4°, however if the soil contains higher composition of both 150 μm and 300 μm particle sizes the deviation is 8°.

Bitumen requirement in hot mix asphalt (HMA) is directly dependent on the surface area of the aggregates in the mix, which in turn has effect on the asphalt film thickness and the flow characteristics. The surface area of aggregate blend in HMA is calculated using the specific surface area factors assigned to percentage passing through some specific standard sieve sizes and the imaging techniques. The first process is less capital intensive, but purely manual and labour intensive and prone to human errors. Imaging techniques though eliminating the human errors, still have limited use due to capital intensiveness and requirement of well-established laboratories with qualified technicians. Most of the developing countries like India are shortage of well-equipped laboratories and qualified technicians. To overcome these difficulties, the present mathematical model has been developed to estimate the surface area of aggregate blend of HMA from physical properties of aggregates evaluated using simple laboratory equipment. This model has been validated compared with the existing established methods of calculations and can be used as one of the tools in different developing and under developed countries for proper design of HMA.

Particle size composition of the soil accumulated on a photovoltaic module influences its power output. It is therefore crucial to understand, quantify and model this soiling phenomenon with respect to particle size composition for predicting soiling losses. Five different soil samples from Shekhawati region in India are collected and relative percentage of standard particle sizes which are 2.36 mm, 1.18 mm, 600 μm, 300 μm, 150 μm, 75 μm and less than 75 μm are determined from sieve analysis. In order to understand and quantify the soiling effect, regression model is developed and to predict the power loss at various levels of irradiances, neural networks model is developed from the obtained experimental data. These models were compared and validated for the power output obtained at wide range of irradiance levels. It was concluded that regression can be used to analyze and quantify the particle size influence on the soiling losses of a PV module while neural networks are efficient in predicting the power output of a soiled panel. It was also observed that influence of 75 μm and lesser size particles is predominant on the power output at low irradiance levels (300–500 W/m2) while it is the 150 μm particle size that impact the power output at higher levels of irradiance (1000–1200 W/m2).

The performance of rotary drill machines commonly used in open-pit mines is measured based on the rate of penetration (ROP) and the bit wear. This paper develops a novel performance evaluation technique to obtain optimal drill operating regime through machine vibration and coarseness index mapping. The vibration levels of blast-hole drilling machines in axial and lateral directions were determined using accelerometers placed at the mast. The mean particle size (d) and characteristic particle size distribution curves for the drilled hole were plotted using sieve analysis and Rosin Rammler diagram. ROP showed an increasing trend with Mean particle size (d) with a correlation of R2 = 0.61 and a decreasing trend with vibration for varied pulldown force and torque at a different rotational speed. A drill vibration index (DVI) is introduced as an indicator of vibration severity of the drill machine, and its relationship was studied with ROP and average mean particle size.

This paper presents a comprehensive characterisation of wood flour geometry for polylactic acid (PLA) wood plastic composites (bioWPCs), and hence explores how the wood flour may influence the microstructure and performance of bioWPCs. The results show that current characterisation of wood flour from the literature can be misleading as they mostly rely on sieve analysis. Image analysis was used to critically study the fibres retained at various mesh sizes to investigate and examine the length and width distributions of the fibres prior to and after processing into bioWPCs. There were clear relationships between the reduction in both fibre size and aspect ratio and compounding processes depending on the original fibre geometry. It was also determined that by sieving out only the fibres retained at 500 µm much stronger bioWPCs can be produced than that using a single size fibre, achieving tensile and flexural stress of 15.3 and 13.2 MPa, respectively.

To address inhomogeneous soil properties during seedbed preparation, a system for site-specific tillage is proposed. The aim of this study was to develop a system to control the rotational speed of the power harrow based on visual detection of the soil roughness with a stereo camera. The basis for the control is the causal relationship between the measurement of soil roughness with stereo cameras, tillage intensity and the aggregate size distribution through dry sieving of the top seedbed. The stereo camera based roughness measurement system developed during this study, focused on robustness and real-time capabilities. Environmental influences on the measurement system were investigated and countermeasures were implemented. The measurement system outputs a roughness index which was the input for a control algorithm. The system was integrated into an ISOBUS Class III application which controls the PTO speed of a tractor in order to prepare a homogeneous soil roughness. During tests several seedbeds with different roughness were prepared with a power harrow following different primary tillage operations. The results of the study have been the basis for the development of a control-approach. The correlations between the aggregate size measured with sieve analysis and soil roughness measured by the stereo vision system was estimated to evaluate the system. Additionally, the comparison between soil roughness and tillage intensity showed high correlation. During validation of the controller, the homogenizing effect on the soil roughness could be shown.

The effect of iron ore tailings (IOT) on cement modified tropical black clay was studied. The natural soil was treated with up to 4% cement and 10% IOT by dry weight of soil. Specimens of treated soil compacted with British Standard light, BSL or standard Proctor (relative compaction = 100%) were subjected to index, sieve analysis, compaction, and shear strength parameters tests. The results of laboratory tests show that properties of the modified soil improved when treated with cement–IOT blends. Test results show a decrease of the fine fraction, decrease in liquid and plastic limits, and an increase in maximum dry density (MDD), with a decrease in optimum moisture content (OMC) as well as a decrease in shear strength value of the natural soil up to 6% IOT content. Microanalysis of the natural and optimally (4% cement/6% IOT) modified soil using scanning electron microscope (SEM) showed a change in the fabric orientation of the soil particles. Although the engineering properties of the soil was improved, the modified soil did not meet the requirements of the Nigerian General Specifications of not more than 35% passing sieve No. 200, maximum plasticity (PI) index of 30% and liquid limit (LL) of a maximum of 50% when used as a sub grade material in road construction. However, an optimal blend of 4% cement/6% IOT improved its workability with increase in curing period.

Although recovery sieve size has vital importance for the success of the oil agglomeration technique for upgrading of fine coals, its effect on the process has been generally omitted in previous studies. Therefore, the present study was undertaken to fill the gap in this area and draw attention to the importance of recovery sieve size. An oxidized fine coal sample was subjected to oil agglomeration process and effect of separation sieve size on the success of the process with regard to combustible recovery and ash–sulphur rejection was investigated. 72.90% of ash, 90.90% of pyritic sulphur, and 87.75% of sulphate sulphur were removed from the coal with combustible recovery of 76.53%. Increase in recovery sieve size had positive effect on removals of ash and sulphur. Recovery sieve size was found to be extremely important for the performance of the process in that combustible recovery reduced sharply with increasing sieve sizes. It was concluded that recovery sieve size should be the same size with the top feed size.