Co,Ce nanoparticles supported on stacked wire mesh cartridges. Activity and stability in diesel soot combustion.

In this work, Co3O4 nanoparticles were successfully synthesized by precipitating a precursor salt solution in the form of microdroplets generated by a nebulizer, as an efficient, fast and low-cost approach. After drying and calcination, synthesized particles were deposited on stacked wire mesh monoliths by immersing the structures in a suspension containing synthesized Co3O4 particles and commercial ceria nanoparticles as a binder. These structured catalysts were evaluated for the combustion of diesel soot which constitutes a crucial step in the regeneration of catalytic particulate filters (CDPFs). Thermal and mechanical stability of Co,Ce washcoated monoliths were investigated. For this, successive catalytic evaluations of the structured system, with intermediate treatments at 900 °C (accelerated aging), were carried out indicating a very good activity and stability of the catalysts developed. Adherence tests showed good adhesion of the catalytic layer to the metallic substrate. Fresh and aged catalysts were fully characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Laser Raman Spectroscopy (LRS) and Temperature-Programmed Reduction (TPR). It was found that the catalytic coating resulted composed of nanometric CeO2 and Co3O4 along with chromium, iron and manganese oxides coming from the migration of the metallic substrate, in the catalytic cartridge calcined at 600 °C. Despite after calcination at 900 °C spinels of Co, Fe, Cr and Mn were observed, these oxides did not significantly affected the catalytic activity. Although this aging treatment at 900 °C was severe and is not expected under real conditions, it highlights the potential application of the catalytic metallic cartridges here developed.

Study on the Particle Deposition Characteristics of Transpiration Cooling Structures with Sintered Wire Mesh.

Transpiration cooling based on a porous structure has an ultra-high cooling efficiency, which is expected to be one solution to improve the cooling technology of aero-engine turbine blades. However, particulate impurities in the gas flow channel continue to deposit on the surface of turbine components, blocking cooling holes, which causes great harm to the cooling of turbine blades. In this study, a sintered metal mesh plate was selected as the transpiration cooling structure, and the evolution of particle deposition quality and deposition thickness on the transpiration cooling surface with time, as well as spatial distributions of particle deposition thickness at different times, were explored through experimental and simulation methods. The results showed that, with the increase in spray time, deposition quality and maximum deposition thickness of the transpiration cooling surface gradually increased. Along the main-stream direction, when spray time was short, deposition thickness was higher in a narrow range upstream of the experimental specimen. With the increase in spray time, deposition thickness gradually decreased along the direction of the transpiration cooling mainstream. In the spanwise direction, when spray time was very short, deposition thickness in the spanwise direction was more consistent and, after spray time increased further, the deposition thickness distribution began to tend to a "∩"-type distribution. It can be seen from the simulation results of the metal wire mesh particle deposition that particles were easily deposited on the windward side of the metal wire in the main-stream direction, which agreed with the experimental distribution characteristics of the metal wire mesh deposition. Moreover, the increase in blowing ratio reduced the deposition of particles on the wall of the metal wire mesh.

Sensitive electrochemical flow injection analysis of H2O2 released from cells with a pass-through mode.

Conventional plate electrodes were commonly used in electrochemical flow injection analysis and only part of molecules diffused to the plane of electrodes could be detected, which would limit the performance of electrochemical detection. In this study, a low-cost native stainless steel wire mesh (SSWM) electrode was integrated into a 3D-printed device for electrochemical flow injection analysis with a pass-through mode, which is different compared with previous flow-through mode. This strategy was applied for sensitive analysis of hydrogen peroxide (H2O2) released from cells. Under the optimal conditions (the applied potentials, the flow rate and the sample volume), the device exhibits high sensitivity toward H2O2. Linear relationships could be achieved between electrochemical responses and the concentration of H2O2 ranging from 1 nM to 1 mM. The excellent analytical performance of the SSWM-based device could be attributed to the pass-through mode based on the mesh microstructure and intrinsic catalytic properties for H2O2 by stainless steel. This approach could be further successfully extended for screening of H2O2 released from HeLa cells with electrochemical responses linear to the number of cells in a range of 3 - 1.35 × 104 cells with an injection volume of 30 µL. This study revealed the potential of mesh electrodes in electrochemical flow injection analysis for cellular function and pathology and its possible extension in cell counting and on-line analysis.

Comparative study of eco-friendly wire mesh configurations to enhance sustainability in reinforced concrete structures.

Recent and past studies mainly focus on reducing the dead weight of structure; therefore, they considered lightweight aggregate concrete (LWAC) which reduces the dead weight but also affects the strength parameters. Therefore, the current study aims to use varied steel wire meshes to investigate the effects of LWAC on mechanical properties. Three types of steel wire mesh are used such as hexagonal (chicken), welded square, and expanded metal mesh, in various layers and orientations in LWAC. Numerous mechanical characteristics were examined, including energy absorption (EA), compressive strength (CS), and flexural strength (FS). A total of ninety prisms and thirty-three cubes were made. For the FS test, forty-five 100 × 100 × 500 mm prism samples were poured, thirty-three 150 × 150 × 150 mm cube samples were made, and forty-five 400 × 300 × 75 mm EA specimens were costed for fourteen days of curing. The experimental findings demonstrate that the FS was enhanced by adding additional forces that spread the forces over the section. One layer of chicken, welded, and expanded metal mesh enhances the FS by 52.96%, 23.76%, and 22.2%, respectively. In comparison to the remaining layers, the FS in a single-layer hexagonal wire mesh has the maximum strength, 29.49 MPa. The hexagonal wire mesh with a single layer had the greatest CS, measuring 36.56 MPa. When all three types of meshes are combined, the CS does not vary in this way and is estimated to be 29.79 MPa. In the combination of three layers, the chicken and expanded wire mesh had the most energy recorded prior to final failure, which was 1425.6 and 1108.7 J, whereas it was found the highest 752.3 J for welded square wire mesh. The energy absorption for the first layer with hexagonal wire mesh increased by 82.81% prior to the crack and by 88.34% prior to the ultimate failure. Overall, it was determined and suggested that hexagonal wire mesh works better than expanded and welded wire meshes.

High-strength, antifogging and antibacterial ZnO/carboxymethyl starch/chitosan film with unique "Steel Wire Mesh" structure for strawberry preservation.

In this work, a multifunctional preservative film of ZnO/carboxymethyl starch/chitosan (ZnO/CMS/CS) with the unique "Steel Wire Mesh" structure is fabricated by the chemical crosslinked of ZnO NPs, CMS and CS. Unlike traditional nano-filled polymer film, the formation of the "Steel Wire Mesh" structure of ZnO/CMS/CS film is based on the synergistic effect of ZnO NPs filled CMS/CS and the coordination crosslinked between CMS/CS and Zn2+ derived from ZnO NPs. Thanks to the "Steel Wire Mesh" structure, the tensile strength and water vapor barrier of 2.5ZnO/10CMS/CS film are 2.47 and 1.73 times than that of CS film, respectively. Furthermore, the transmittance of 2.5ZnO/10CMS/CS film during antifogging test is close to 89 %, confirming its excellent antifogging effects. And the 2.5ZnO/10CMS/CS film also exhibits excellent long-acting antibacterial activity (up to 202 h), so it can maintain the freshness and appearance of strawberries at least 5 days. More importantly, the 2.5ZnO/10CMS/CS film is sensitive to humidity changes, which achieves real-time humidity monitoring of the fruit storage environment. Note that the preparation method of the film is safe, simple and environmentally friendly, and its excellent degradation performance will not bring any problems of food safety and environmental pollution.

Fast pyrolysis kinetics of waste tires and its products studied by a wireless-powered thermo-balance.

Fast pyrolysis is commonly used in industrial reactors to convert waste tires into fine chemicals and fuels. However, current thermogravimetric analyzers are facing limitations that prevent the acquisition of kinetic information. To better understand the reaction kinetics, we designed a novel thermo-balance device that was capable of in-situ weight measurement during rapid heating. The results showed that the reaction rate substantially increased, with significant reductions in reaction time and apparent activation energy compared to slow pyrolysis. The change of reaction mechanism from the reaction order model to the nucleation and growth model was responsible for the increase in the degradation rate. Fast pyrolysis led to the generation of more trimers of isoprene as primary pyrolytic volatiles, which we further supported through density functional theory calculations. The findings suggested that fast pyrolysis has a higher chance of overcoming the high energy barrier to form trimers of isoprene. This comprehensive and in-depth understanding of fast pyrolysis kinetics and product distribution could reveal a more realistic process of waste pyrolysis, which benefited the industry.

Development of Electrodeposited Wire Mesh Grinding Wheel for Cutoff and Grooving Carbon Fiber Reinforced Plastic.

Carbon fiber reinforced plastic (CFRP) is used in various industries because of its high specific strength, but it is well known as a difficult material to cut. In this study, we developed a disc-shaped electrodeposited diamond wire mesh grinding wheel as a new method for cutoff and grooving with a large aspect ratio for CFRP. We confirmed that this tool could be used for machining at a feed rate of 1000 mm/min, equivalent to that of an abrasive waterjet. This tool discharges generated chips through the spaces in the wire mesh, preventing clogging and thereby enabling the suppression of machining temperature. No burrs or delamination were observed on the surface machined with the wire mesh grinding wheel, and the surface roughness was Ra = 2.76 µm. However, the groove width was larger than the wheel thickness due to the runout of the wheel. Additionally, the moderate elasticity and durability of the tool suggest that it might extend tool life by avoiding the crushing of abrasive grains.

Experimental Study on Lap-Spliced Performance of High-Strength Stainless Steel Wire Mesh in Engineering Cementitious Composites.

To investigate the mechanical properties of high-strength stainless steel wire mesh (HSSSWM) in Engineering Cementitious Composites (ECCs) and determine a reasonable lap length, a total of 39 specimens in 13 sets were designed and fabricated by considering the diameter of the steel strand, spacing of the transverse steel strand, and lap length. The lap-spliced performance of the specimens was tested through a pull-out test. The results revealed two failure modes in the lap connection of steel wire mesh in ECCs: pull-out failure and rupture failure. The spacing of the transverse steel strand had little effect on the ultimate pull-out force, but it restricted the slip of the longitudinal steel strand. A positive correlation was found between the spacing of the transverse steel strand and the slip amount of the longitudinal steel strand. With an increase in lap length, the slip amount and 'lap stiffness' to peak load increased, while the ultimate bond strength decreased. Based on the experimental analysis, a calculation formula for lap strength considering the correction coefficient ß was established.

Experimental Study and Numerical Analysis on the Shear Resistance of Bamboo Fiber Reinforced Steel-Wire-Mesh BFRP Bar Concrete Beams.

Bamboo fiber is a natural and environmentally friendly material made from cheap and widely available resources and is commonly selected as the reinforcement material for steel-wire-mesh BFRPbar concrete beams. In this work, the effects of various fiber lengths and fiber volume rates on the shear properties of bamboo-fiber-reinforced steel-wire-mesh basalt fiber composite reinforcement concrete beams were studied through a combination of shear tests and numerical simulations. The findings demonstrate that the addition of bamboo fiber improves the cracking performance of the beam. The improvement effect of 45 mm bamboo fiber mixed with a 1% volume rate was the most obvious at about 31%. Additionally, the test beam's total stiffness was increased, and the deflection was decreased. However, the use of bamboo fiber was found to decrease the concrete's compressive strength, lowering the final shear capacity for the majority of beams. A method for estimating the shear capacity of the bamboo-fiber-reinforced steel-wire-mesh BFRPbar concrete beams is provided and lays the foundation for engineering practice, in accordance with the impact of bamboo fiber and steel wire mesh on beams that suffer shear breaks.

Towards Real-Time Analysis of Gas-Liquid Pipe Flow: A Wire-Mesh Sensor for Industrial Applications.

Real-time monitoring of gas-liquid pipe flow is highly demanded in industrial processes in the chemical and power engineering sectors. Therefore, the present contribution describes the novel design of a robust wire-mesh sensor with an integrated data processing unit. The developed device features a sensor body for industrial conditions of up to 400 °C and 135 bar as well as real-time processing of measured data, including phase fraction calculation, temperature compensation and flow pattern identification. Furthermore, user interfaces are included via a display and 4…20 mA connectivity for the integration into industrial process control systems. In the second part of the contribution, we describe the experimental verification of the main functionalities of the developed system. Firstly, the calculation of cross-sectionally averaged phase fractions along with temperature compensation was tested. Considering temperature drifts of up to 55 K, an average deviation of 3.9% across the full range of the phase fraction was found by comparison against image references from camera recordings. Secondly, the automatic flow pattern identification was tested in an air-water two-phase flow loop. The results reveal reasonable agreement with well-established flow pattern maps for both horizontal and vertical pipe orientations. The present results indicate that all prerequisites for an application in industrial environments in the near future are fulfilled.

Effect of Normal and Rubberized Concrete Properties on the Behavior of RC Columns Strengthened with EB CFRP Laminates and Welded Wire Mesh under Static Axial Loading.

The huge amounts of old and damaged tires spread worldwide has caused many complex environmental risks. The old tires have been converted to crumb rubber (CR) and tire recycled steel fiber (RSF) to facilitate their use. This study used CR to partially replace natural sand in reinforced (RC) columns. Externally bonded (EB) carbon-fiber-reinforced polymer (CFRP) laminates, welded wire mesh (WWM), and RSF were used to enhance the axial behavior of the tested columns to overcome the concrete deficiencies resulting from the inclusion of the CR instead of natural sand. Eighteen columns were prepared and tested to discuss the effects of strengthening type, CR content, RSF, and strengthening area on the axial behavior of the RC columns. Certain columns were internally reinforced with WWM, while others were externally strengthened with EB CFRP laminates. Partially or fully EB CFRP laminates were used to strengthen the columns. Moreover, one column was cast with NC and 0.2% RSF to investigate the role of RSF in confining the column. The results demonstrated a concrete strength reduction for the rubberized concrete (CRC) as the CR content increased. Conversely, the strengthened columns experienced higher load capacities than the corresponding un-strengthened ones cast with the same concrete mix. Moreover, adding 2% RSF to the NC mix could enhance the column capacity, although it decreased the concrete strength. Furthermore, using two CFRP layers increased the load capacity and ductility of the strengthened columns. The strengthened column cast with 50% CR showed the highest load efficiency (334.3% compared to the un-strengthened one).

Comparing wire-mesh sensor with neutron radiography for measurement of liquid fraction in foam.

The liquid fraction of foam is an important quantity in engineering process control and essential to interpret foam rheology. Established measurement tools for the liquid fraction of foam, such as optical measurement or radiography techniques as well as weighing the foam, are mostly laboratory-based, whereas conductivity-based measurements are limited to the global measurement without detailed spatial information of liquid fraction. In this work, which combines both types of measurement techniques, the conductivity-based wire-mesh sensor is compared with neutron radiography. We found a linear dependency between the liquid fraction of the foam and the wire-mesh readings with a statistical deviation less than 15%. However, the wire-mesh sensor systematically overestimates the liquid fraction, which we attribute to liquid bridge formation between the wires.

Analytical and Numerical Modeling of the Pullout Behavior between High-Strength Stainless Steel Wire Mesh and ECC.

Bond behavior is a key factor in the engineering application of composite material. This study focuses on the constitutive model of the bond behavior between high-strength stainless steel strand mesh and Engineered Cementitious Composites (ECC). In this paper, the effects of strand diameter, bond length and transverse steel strand spacing on bond behavior were studied based on 51 direct pullout tests. Experimental results showed that the high-strength stainless steel strand mesh provided specimens an excellent ductility. Based on the experimental data, the existing bond-slip model was revised using the theory of damage mechanics, which fully considered the influence of the steel strand diameter on the initial tangent stiffness of the bond-slip curve. The results of the model verification analysis show that errors are within 10% for most parameters of the bond-slip model proposed, especially in the ascending section, the errors are within 5%, indicating that the calculated results using the revised model are in good agreement with the test results. In addition, the revised model was applied to the finite element analysis by using the software ABAQUS to simulate the pullout test, in which the spring-2 nonlinear spring element was used to stimulate the bond behavior between steel strand meshes and ECC. The simulation results show that the numerical analysis fits the experimental result well, which further verifies the accuracy of the model and the feasibility and applicability of the numerical analysis method.

Experimental Investigation on the Transpiration Cooling Characteristics of Sintered Wire Mesh in Plain Weave.

We experimentally investigate the transpiration cooling characteristics of a porous material, sintered wire mesh. Three samples with different porosities in a plain weave structure are tested with various blowing ratios in an open-loop wind tunnel with a heated mainstream flow. The temperature on the surface of the porous material is measured by an infrared camera to obtain the cooling efficiency. The measurements reveal nonuniform distributions of the surface temperature and the cooling efficiency in both the flow direction and the transverse direction. The averaged cooling efficiency on the surface first decreases and then increases with the blowing ratio, but increases and then decreases with the porosity of the material. The internal cooling by forced convection and its combination with the external film cooling from the transpiration cooling are considered to be attributed to those two cooling characteristics, respectively. Finally, we propose a modified blowing ratio to collapse the minima of the blowing ratio for all tested samples, providing an universal transition for the decreasing and increasing branches for all tested samples in the relation between averaged cooling efficiency and blowing ratio.

Feasibility Study on the Steel-Plastic Geogrid Instead of Wire Mesh for Bolt Mesh Supporting.

Wire mesh is a common material for bolt mesh supporting structures, but its application in engineering has revealed many defects. At the same time, with the development of new materials for civil engineering, the new material mesh performance and cost show outstanding advantages over wire mesh. In this paper, the feasibility of replacing wire mesh with steel-plastic geogrid as an alternative material is carefully studied through indoor tests and field applications. The following conclusions were drawn from a comparative analysis with wire mesh, mainly in terms of mechanical properties, engineering characteristics, and construction techniques: (1) in terms of mesh wire strength, wire mesh is slightly better than steel-plastic geogrid, but in the case of similar tensile strength, the amount of steel used per unit length of steel geogrid bars is only 36.75% of that of steel-plastic geogrid, while the tensile strength of the high-strength steel wire attached to the steel-plastic geogrid belt is about 3.3 times that of steel bars; (2) in terms of junction peel strength, both values are similar, with the injection-moulded junction being 1154.56-1224.38 N and the welded junction of 4 mm mesh being 988.35 N; (3) in terms of the strength of the mesh, steel-plastic geogrid is better than wire mesh, and with the same mesh wire strength, the bearing capacity of steel-plastic geogrid is increased by about 63.17% and the contribution of the mesh wire bearing capacity is increased by 83.66%, with the damage mainly being in the form of wire breakage in the ribbon causing ribbon failure, leading to further damage to the mesh; (4) in terms of the engineering application of steel-plastic geogrid compared to wire mesh, the utilization rate of mesh increases by about 24.99%, the construction efficiency increases by about 14.10%, and the economic benefit increases by about 45.31%. In practical application, the steel-plastic geogrid has good adhesion with surrounding rock and strong corrosion resistance. According to the above research analysis, the steel-plastic geogrid is feasible to replace the wire mesh for bolt mesh supporting.

Enhanced analytical performance of disposable 3D carbon electrodes prepared with stainless steel wire mesh.

This paper aims to use low-cost stainless steel wire mesh (SSWM) as uniform templates to prepare disposable three-dimensional (3D) carbon electrodes to improve their analytical performance. Native SSWM electrodes were prepared with lamination and then coated with carbon cement for bulk preparation of disposable 3D carbon electrodes with drop-casting. The electrodes were then coupled in paper-based analytical devices. Meanwhile, disposable 2D carbon electrodes were prepared with the stainless steel sheets (SSSs) for comparison under the same condition using stripping analysis of heavy metals as a model. Our results demonstrated that the sensitivity of the 3D carbon electrodes was about three times as high as that of the 2D carbon electrodes on stripping analysis of both heavy metals. The electrochemical responses of 1 µg L-1 Pb2+ at the 3D carbon electrodes were about 6 times as high as those at the 2D carbon electrodes. The improved analytical performance of disposable 3D carbon electrodes could be attributed to their increased electrochemical effective area, which was brought by replacing SSSs with SSWM. The obtained disposable 3D carbon electrodes could be used for differentiation of Pb in teethers and corns. This study not only presented the potential of SSWM in the preparation of disposable 3D carbon electrodes but also suggested a simple and effective strategy for the preparation of disposable 3D electrodes for practical applications.

Charpy Impact Behavior of a Novel Stainless Steel Powder Wire Mesh Composite Porous Plate.

A novel powder wire mesh composite porous plate (PWMCPP) was fabricated with 304 stainless steel powders and wire mesh as raw materials by vacuum solid-state sintering process using self-developed composite rolling mill of powder and wire mesh. The effects of different mesh volume fractions, mesh diameters, and sintering temperatures on the pore structure and Charpy impact properties of PWMCPPs were studied. The results show that PWMCPPs have different shapes and sizes of micropores. Impact toughness of PWMCPPs decreases with increasing wire mesh volume fraction, and increases first and then decreases with increasing wire mesh diameter, and increases with increasing sintering temperature. Among them, the sintering temperature has the most obvious effect on the impact toughness of PWMCPPs, when the sintering temperature increased from 1160 °C to 1360 °C, the impact toughness increased from 39.54 J/cm2 to 72.95 J/cm2, with an increased ratio of 84.5%. The tearing between layers, the fracture of the metallurgical junction, and the fracture of wire mesh are the main mechanisms of impact fractures of the novel PWMCPPs.

Preparation and Tensile Properties of Novel Porous Plates Made by Stainless Steel Wire Mesh and Powder Composites.

Porous metal materials have important mechanical properties, and there are various manufacturing methods to produce them. In this paper, a porous, thin strip was fabricated by the composite rolling of stainless steel wire mesh and stainless steel powder. Then, a porous plate of stainless steel wire mesh and powder composite (SWMPC) was prepared by folding, pressing, and vacuum sintering the thin strip, and its structural characteristics and permeability were studied. The effects of the gap of the roller, gap of the powder box, number of layers by folding, and sintering parameters on the porosity and mechanical properties were also studied. The results indicated that the permeability increased with the increasing of porosity. Sintering parameters had a great influence on the mechanical properties. The larger the roll gap, the higher the porosity and the weaker the mechanical properties. As the gap of the powder box increased, the porosity decreased and the mechanical properties improved. The number of layers had no effect on the porosity. The first three stages of tensile curves of 10 and 15 layers were deformation stages and generally coincided, the time was short at the fracture stage. However, the mechanical properties got a raise when layers was 15.

Temperature Compensation for Conductivity-Based Phase Fraction Measurements with Wire-Mesh Sensors in Gas-Liquid Flows of Dilute Aqueous Solutions.

Wire-mesh sensors are well-established scientific instruments for measuring the spatio-temporal phase distribution of two-phase flows based on different electrical conductivities of the phases. Presently, these instruments are also applied in industrial processes and need to cope with dynamic operating conditions increasingly. However, since the quantification of phase fractions is achieved by normalizing signals with respect to a separately recorded reference measurement, the results are sensitive to temperature differences in any application. Therefore, the present study aims at proposing a method to compensate temperature effects in the data processing procedure. Firstly, a general approach is theoretically derived from the underlying measurement principle and compensation procedures for the electrical conductivity from literature models. Additionally, a novel semi-empirical model is developed on the basis of electrochemical fundamentals. Experimental investigations are performed using a single-phase water loop with adjustable fluid temperature in order to verify the theoretical approach for wire-mesh sensor applications and to compare the different compensation models by means of real data. Finally, the preferred model is used to demonstrate the effect of temperature compensation with selected sets of experimental two-phase data from a previous study. The results are discussed in detail and show that temperature effects need to be handled carefully-not merely in industrial applications, but particularly in laboratory experiments.

Aggregate Roundness Classification Using a Wire Mesh Method.

Herein, we suggest a wire mesh method to classify the particle shape of large amounts of aggregate. This method is controlled by the tilting angle and opening size of the wire mesh. The more rounded the aggregate particles, the more they roll on the tilted wire mesh. Three different sizes of aggregate: 11-15, 17-32, and 33-51 mm were used for assessing their roundness after classification using the sphericity index into rounded, sub-rounded/sub-angular, and angular. The aggregate particles with different sphericities were colored differently and then used for classification via the wire mesh method. The opening sizes of the wire mesh were 6, 11, and 17 mm and its frame was 0.5 m wide and 1.8 m long. The ratio of aggregate size to mesh-opening size was between 0.6 and 8.5. The wire mesh was inclined at various angles of 10°, 15°, 20°, 25°, and 30° to evaluate the rolling degree of the aggregates. The aggregates were rolled and remained on the wire mesh between 0.0-0.6, 0.6-1.2, and 1.2-1.8 m depending on their sphericity. A tilting angle of 25° was the most suitable angle for classifying aggregate size ranging from 11-15 mm, while the most suitable angle for aggregate sizes of 17-32 and 33-51 mm was 20°. The best ratio for the average aggregate size to mesh-opening size for aggregate roundness classification was 2.