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This study aimed to develop a highly selective extraction protocol for gold (AuIII) ions from electronic urban waste (EUW) using simple, low-cost Inorganic-organic mesoporous hybrid segregators. The unique features of mesoporous hybrid segregator architectures are of particular to ensure effective adsorption system in terms of selective and sensitive recovery of AuIII ions from EUW. The segregator platform featured 3D micrometric, mesocage double-serrated plant-leaf-like γ-Al2O3 sheets with hierarchy surfaces containing tri-modal mesopores interiorly and uniformly arranged toothed edges of ~20–40 and ~15 nm groove width and depth at the exterior surfaces, respectively. Rational incorporation of actively organic chelates into hierarchical γ-Al2O3 sheet platforms leads to the production of a couple of selective segregators 1 and 2 (namely, SC1 and SC2) for AuIII ions at specific conditions by applying batch and fixed-bed columnar techniques. The mesocage SC segregators offer a selective extraction approach of AuIII ions from mixed element contents released from a computer motherboard (CMB). Our finding indicated that the textural and hierarchal features of the mesocage SC segregators played key roles in the selective adsorption/recovery of AuIII ions at pH 2–2.5 with high capacity (136–141 mg/g range) and effective reusability ≫10 consecutive cycles. In general, the developed SCs could be utilized as a real extractor of AuIII recovery from spent CMBs.

The structural parameter of spiral groove has a great influence to spiral-grooved thrust bearing. Unsuitable value of spiral groove will lead to the poor hydrodynamic performance of spiral-grooved thrust bearing, namely vibration, wear and impact contact. This study proposes a new computational model and conducts the performance analysis of spiral-grooved thrust bearing. Based on the Navier–Stokers equation, the hydrodynamic analysis model can be applied to illustrate the lubrication performance of oil film. And, the proposed simulation model can be demonstrated by the experiment data. Additionally, the effects of groove length, groove width and groove number on lubrication performance characteristics of spiral-grooved thrust bearing are investigated.

A grooved texture surface was fabricated to enhance the wear resistance of the guide rail surface of molding machine. The effects of sand concentration in the oil and the groove width on the tribol...

The helical grooved seal, which is a non-contact sealing device using the viscosity of the fluid, prevents leakage by reducing fluid pressure according to the shapes of the rotor and stator. It has been widely adopted to turbomachinery because no wear deliveries high efficiency, unlike to the existing contact sealing device. In this study, parametric study was performed by CFD analysis, considering helical grooved seal shape: ratio of groove width and land width (Wratio), helical angle (β) and groove depth (d). Based on the leakage characteristics analyzed through CFD results, improved seal shape of the helical grooved seal to reduce leakage was suggested.

Surface groove morphology of structure and particle distribution of soil had a significant effect on the surface friction of structure. In order to investigate the interface shear stress-shear displacement curves, interface model and interface shear strength index when normal stress, groove width, and groove angle change, the interface shear tests of standard sand with steel plates are performed using an improved direct shear apparatus. Test results indicate that the peak shear stress increases with normal stress and the intersection angle between groove direction and shear direction. When the angle increases by 45°, the peak shear stress increases range from 4% to 13%. The peak shear stress increases with groove width, for every 1 mm increase in groove width, and the increasing extent of peak shear stress ranges from 4% to 22%, 3% to 13%, and 1% to 6%, respectively. When the groove angle is 45° and 90°, the increasing extent of peak shear stress decreases with groove width, but when the groove angle is 0°, the decrease regularity of peak shear stress increasing extent is not obvious. The hyperbolic model and Gompertz-C model are used to study the shear stress-shear displacement curves of sand-steel interface. The ratio of the interface peak shear stress of the hyperbolic model and Gompertz-C model to that of the shear test ranges from 0.90 to 1.03 and 0.88 to 0.98, respectively. The interface friction angle at the sand-steel interface ranges from 22° to 29°, and the friction angle of the rough interface is larger than that of the smooth interface. The interface friction angle increases with the intersection angle between the groove direction and the shear direction, the largest at 90°, the second at 45°, and the smallest at 0°. Under the same groove angle, the interface friction angle increases with the groove width, for every 1 mm increase in groove width, and the increasing extent of interface friction angle ranges from 4% to 15%, 4% to 7%, and 2% to 3%, respectively. The increasing extent of interface friction angle decreases with groove width, and this change rule is more obvious at the groove angle of 45° and 90° than at 0°.

Based on dimensional analysis and finite element simulation, a new method is proposed to characterize the yield stress and interfacial coefficient of friction of materials by scratching with a Vickers indenter. Two simple equations are obtained: one is for determining the interfacial coefficient of friction between the scratched material and scratch tip via the ratio of tangential to normal force, and the other is for calculating the yield stress of scratched material with the groove width and normal force. In a case study, the method is applied to soda-lime and borosilicate glasses. It is shown that the measured results of yield stress and interfacial coefficient of friction between glasses and a diamond tip are consistent with that obtained by other methods, with a high accuracy. The quick and accurate determination of yield stress and interfacial friction coefficient provides important information for the design and processing of glass products.

In this study, a method of micro-electrochemical slab milling with disc electrode is proposed for fabricating micro-groove structures on the surface of the workpiece. The disc electrode is in-situ prepared by micro-WEDM and subsequently used for micro-electrochemical slab milling process. The effects of the main electrochemical parameters, such as electrode feed rate of disc electrode and pulse width of power generator, on the width of the micro grooves and surface quality on 304 stainless steel were discussed. Finally, a micro-groove with a groove width of 254μm and good surface quality has successfully processed using the disc tool electrode with edge width of 170μm and proper process parameters. The proposed method broadens the machining flexibility and capability of micro electrochemical machining technology.

Setting the micro-texture in the cutter–chip contact area of a micro-textured tool rake face can effectively improve the tool’s cutting performance. However, an unreasonable design for the micro-groove morphology and size and the selection of inappropriate cutting parameters will cause a secondary cutting phenomenon during the cutting process. To explore the optimum micro-texture morphology size and cutting parameters, micro-texture self-lubricating ceramic cutting tools with different morphology parameters (micro-texture location distribution: MSTD-1, MSTD-2, MSTD-3; groove spacing: MSTS-1, MSTS-2, MSTS-3; groove width: MSTW-1, MSTW-2, MSTW-3) were formed in situ and by hot pressing sintering, and a dry cutting 40Cr comparison test with a non-textured tool (MST-0) was conducted. The results revealed that the MSTD-2 tool effectively reduced the cutting force, friction factor, and rake face wear and relieved the secondary cutting phenomenon while cutting 40Cr. A theoretical analysis showed that the micro-texture morphology parameters and cutting speed were the main factors affecting the secondary cutting, with a smaller groove width and higher cutting speed associated with a lighter chip impact.

Sheet-type resin floors possess a risk of slipping during rains or liquid spills. We investigated the friction properties of vinyl flooring sheets using shoes and glycerol solution, and clarified the combined effect of the groove's depth and width and a urethane coating on the coefficient of friction (COF). According to the analysis, the static COF could be expressed using the spreading coefficient. All the dynamic COFs could be expressed using the spreading coefficient and aspect ratio of the grooves. All the COFs were significantly affected by the interfacial tension at the triple line but were relatively unaffected by the groove shape.

Electrochemical turning (ECT) has been studied by researchers for making axially symmetric parts of different materials by using shaped tools fed radially into the rotating workpiece. Despite having various advantages over other advanced machining processes, ECT has failed to gain much attention by the manufacturing industries and researchers because of the complexity involved in designing a shaped tool to give a desired shape and tolerances to the workpiece. In the present work, a systematic study is presented to understand the applicability of a microwire as a replacement for a shaped tool in this process. Simulations are carried out to understand the distribution of electric field lines and current density in case of wire electrochemical turning (ECT). The effects of insulting wire up to different angles on the evolved groove profile are investigated by performing simulation study. Minimum groove width is observed at the lowest value of ‘tool exposed angle’ (30°), while maximum groove depth is observed at the highest value of tool exposed angle (270°). In the later part of the work, an experimental study is performed to characterize a groove profile using a bare copper wire of diameter 200 µm. The effects of input parameters, such as workpiece rpm, tool radial insertion, applied potential and electrolyte concentration on responses like groove width, corner radius and taper angle are investigated. Finally, the understanding of behaviour of different process parameters is applied to perform operations like multi-step turning, microgroove turning and taper turning on copper and micro-threading on stainless steel 304.

The penetration of the bead for swing arc vertical-up backing welding was investigated by experiments and numerical simulations in the present work. Three double groove types were used: double V groove, one V-one trapezoid groove, and double compound angle groove. The molten pool behaviors and the weld-forming mechanisms for different grooves were studied. The results indicate that the groove assembly dimensions affect the penetration of the backing weld. As the root gap increases or the root face decreases, the penetration increases. For one V-one trapezoid groove, the increase of the groove width leads to the decrease of the penetration. Based on the analysis of the weld-forming mechanisms, a double compound angle groove was proposed and applied, and a better full penetration can be obtained. Through the analysis of simulation results, the optimized groove for double-sided swing arc vertical-up metal active gas (MAG) welding was obtained.

The iron loss of inner yoke accounts for the majority of iron loss of an electromagnetic linear actuator (ELA). Therefore, the reduction of iron loss of inner yoke is of great importance to the reduction of iron loss of the whole ELA. This study investigates the formation mechanism and distribution law of ELA iron loss and proposes a reduction scheme by arranging groove structures in the inner yoke. The direction of groove arranged in inner yoke was determined based on the formation mechanism of inner yoke iron loss. Through simulation and calculation based on finite-element model of electromagnetic field, the authors investigated the effects of the number of grooves as well as groove width on the iron loss and performance of ELA. The optimal grooving scheme of ELA was determined by comprehensive analysis and analytic hierarchy process. Finally, block and static force tests were carried out based on ELA prototype. It was found that the simulation results were consistent with test results, indicating the accuracy of the simulation model.

To address the significant subsurface damage of a workpiece after grinding by a coarse-grained wheel, the research on nanosecond ultraviolet laser micro-structuring of a coarse-grained diamond-grinding wheel was carried out, and the influence of process parameters on the depth and width of the groove, the micro-structuring efficiency, and the qualification rate of micro-structured grains were explored. The results show that the single-pass laser circular cutting method cannot achieve the desired groove size even with an arbitrarily large number of scanning cycles. The multi-pass laser circular cutting method can effectively improve the micro-structuring efficiency, and the width and depth of the groove increased and decreased respectively with the increase of the pass spacing. The qualification rate of micro-structured grains was related to the groove spacing, the distribution of the grains on the surface of the grinding wheel, the grain diameter, and the groove width. Under the assumption that the grains were evenly distributed on the surface of the grinding wheel, the qualification rate first increased and then decreased with the increase of the groove spacing.

Paper represents an analysis of the influence of oil groove width and bearing clearance on the characteristics of oil film in a hydrodynamic journal main crankshaft bearing. Analysis was performed to define the influence of bearing clearance and dimensions of oil grooves on static characteristics and manufacturability of half-shelf bearings in industrial high-volume production. Computer simulations were made using an ARTbear program, which was developed in Department of Machine Construction and Vehicle Design in Gdańsk Technical University. The analysis allowed defining the correlation between groove geometry and load capacity and working conditions of bearings. Potential opportunities of possible shortening of production time in high-volume production were also indicated.

Purpose The purpose of this study is to investigate the hydrodynamic lubrication characteristics of ferrofluid film for spiral groove mechanical seal in external electromagnetic field and to analyze the effects of the volume fraction of ferrofluid, parameters of the electromagnetic field, operating parameters and geometrical parameters of mechanical seal on the characteristics of ferrofluid film. Design/methodology/approach The relationship between the ferrofluid viscosity and the intensity of external electromagnetic field was established. Based on the Muijderman narrow groove theory, the pressure distribution was calculated with the trial method by trapezoid formula. Findings It was found that pressure, average viscosity, average density and opening force of ferrofluid between end faces increase with the increase in intensity of current, volume fraction of ferrofluid, rotating speed, pressure differential and spiral angle; decrease with the increase in temperature; and increase at first and then decrease with the increase in the ratio of groove width to weir and the groove length. All of them reach the maximum value when the ratio of width of groove to weir is 0.7 and the ratio of groove length is 0.6. Leakage of ferrofluid increases with an increase in intensity of current, volume fraction of ferrofluid, rotating speed, pressure differential, spiral angle and ratio of groove length; decreases with an increase in temperature; and increases at first and then decreases with the increase in the ratio of groove width to weir. The tendencies of characteristics of silicone oil are consistent with those of ferrofluid, and the characteristics of silicone oil are smaller than those of ferrofluid under the same condition. Originality/value The volume fraction of ferrofluid, rotating speed, spiral angle, ratio of groove width to weir, groove length and temperature have a significant influence on the characteristics of ferrofluid film; however, intensity of current and the pressure differential have slight influence on the characteristics of ferrofluid film. An analytical method for analyzing hydrodynamic lubrication characteristics of ferrofluid film in a spiral groove mechanical seal was proposed based on the Muijderman narrow groove theory.

Purpose The purpose of this study is to elucidate the size effect (groove width, unit length and area density) of the hexagonal texture on tribological properties under lubrication. Design/methodology/approach The tribological properties of nine hexagonal textures with different hexagon lengths and groove widths have been investigated under mixed lubrication to elucidate the size effect. Findings Overall, the friction coefficient decreases as the groove width increases within the examined range, whereas the hexagon length shows an optimal value around 3 mm. In particular, one hexagonal texture (3 × 3 mm) exhibits lower friction coefficients and less wear losses than the others. Interestingly, two hexagonal textures of similar area density (1 × 1 mm and 3 × 3 mm) yield the worst and best tribological performances, respectively, which can be explained by the simulated distribution of equivalent stress. Originality/value The tribological properties of nine hexagonal textures are examined under lubrication. The 3 × 3 texture exhibits lower friction coefficient and wear loss than the others. Two textures of similar area density yield the worst and best tribological performances. The results agree with the simulated distribution of equivalent stress.