Ball Size Research Articles

Potential Effects of Soccer Ball Characteristics on Ball-to-Head Contact: A Systematic Review

Background: The aim of this study was to systematically review research on the effect of soccer ball characteristics on ball-to-head contact. Methods: This systematic review was conducted using electronic databases, which included PubMed, Cochrane, and Web of Science. The search strategy combined keywords related to soccer, the ball and its characteristics, heading, and kinematics variables. Studies analyzing the impact of soccer ball characteristics on heading biomechanics were included. The review included studies using mathematical models, simulations, and human subjects. Results: A total of nine studies were included, highlighting the lack of evidence on this topic. The following ball characteristics were investigated: inflation pressure (n = 7), mass (n = 4), structure/material properties (n = 3), size/diameter (n = 3), and stiffness (n = 3). Most studies used non-human subjects, such as mathematical, simulated, or head-form models. Key findings were as follows: (a) reducing inflation pressure may decrease impact magnitude; (b) ball size may not directly relate to impact magnitude, but one study found that a smaller size resulted in a shorter impact time; (c) lower impact observed with decreasing ball mass; (d) lowering stiffness showed a tendency to lower impact; (e) two studies on water absorption found that wet balls were heavier and had greater impact forces than dry balls; and (f) ball structure and cover material directly influenced impulsive forces. Conclusions: Modifying soccer ball characteristics may reduce heading forces, but the available research has limitations. More controlled studies are needed to determine optimal ball properties for mitigating injury risk during soccer heading. Standardized testing methods can further clarify the biomechanics of heading, supporting ongoing innovations to enhance player experience.

CO2 capture using red mud & mechanically-activated red mud and its kinetics under ambient conditions

Greenhouse gas emissions and the growing stockpiles of red mud, an alkaline industrial waste with potential for CO2 sequestration, present significant environmental challenges. This article aims to enhance the CO2 sequestration capacity of red mud by mechanically activating its surface using a high-energy planetary ball mill for extended grinding periods. The novelty of the study lies in investigating the CO2 sequestration capacity and evaluating its kinetics includingadsorption and desorption on feed and mechanically-activated red mud under atmospheric temperature and pressure for the first time via a direct gas–solid carbonation route using a fixed bed column. The effect of ball size (10,8 and 6 mm) used in high-energy planetary ball mills while mechanical activation, CO2 flow rate (20–80 ml/min), and reaction time (1–5 h) on the CO2 capture has been studied. Apart from this, experimental data on CO2 sequestered (1–5 h) and the extent of CO2 desorption (7–35 days) are fitted to various kinetic models, including pseudo-first-order, pseudo-second-order, and Avrami’s fractional order models. Results showed that the CO2 sequestration capacity of feed red mud is 3.75 mg/g, while the capacity of mechanically-activated red mud increased to 18.28 mg/g, with an adsorption time of 5 h at ambient temperature and pressure. The most suitable fit is attained with Avrami’s fractional order model, suggesting that both physisorption and chemisorption contribute to enhancing the CO2 sequestration capacity of red mud. The mechanism for this process has also been proposed along with the suitable characterizations.

Preparation of M-type barium ferrite submicron absorbing powder by one-step high-temperature ball milling and its particle structure regulation

This study investigates a simple and rapid process for directly preparing M-type barium ferrite using high-temperature ball milling. By adjusting the rotation speed of the high-temperature ball milling, the morphology and size of the powder can be altered to regulate its electromagnetic properties, aiming for an overall good absorbing effect. The powder’s morphology, agglomeration properties, elemental valence states, and electromagnetic parameters were characterized using SEM, BET, XPS, EDS, and VNA. The results show that as the milling speed increases, the particle size of the M-type barium ferrite decreases, transitioning from the typical hexagonal flake particles to spherical block particles, forming a porous loose structure with richer dielectric loss mechanisms and enhanced electromagnetic wave loss capacity. Electromagnetic loss performance analysis indicates that at a milling speed of 50 rpm, the powder achieves the best electromagnetic loss of −61.16 dB at a matching thickness of 8.77 mm and a microwave absorption bandwidth of 4.1 GHz.

Investigating the Influence of Medium Size and Ratio on Grinding Characteristics

This study explores the effect of steel ball size and proportion on mineral grinding characteristics using Discrete Element Method (DEM) simulations. Based on batch grinding kinetics, this paper analyzes the contact behavior during grinding, discussing particle breakage conditions and critical breakage energy. The results indicate that while increasing the size of the steel balls leads to higher collision energy, the collision probability decreases significantly; the opposite is true for smaller steel balls. Simulation results with different ball size combinations show that increasing the proportion of smaller balls does not significantly change the collision energy but greatly increases the collision probability, providing a basis for optimizing ball size distribution to improve grinding performance. Furthermore, appropriately increasing the proportion of smaller balls can reduce fluctuations in grinding energy consumption, thereby enhancing collision energy and collision probability while reducing energy costs. Liner wear results demonstrate that larger ball sizes increase liner wear, but different ball size combinations can effectively distribute the forces on the liner, reducing wear.

Analysis of precision loss of double-nut ball screw considering dimensional error and preload degradation

Abstract A ball screw is a critical drive component capable of converting force into motion, with widespread applications in the high-precision mechanisms of various machine tools. The degradation in precision attributed to ball screw wear significantly impacts machine tool accuracy. Current ball screw wear models lack consideration for the ramifications of radial forces and ball size errors.This study introduces a pioneering approach by formulating a coupled model that integrates screw wear, ball wear, and preload degradation. Through rigorous analysis, we discern the multifaceted influences of axial force, radial force, preload adjustments, and ball size precision on the positional accuracy of ball screws.By elucidating the intricate interplay among these parameters, this study offers crucial theoretical insights into the selection and optimization of ball screws, thereby fostering advancements in machine tool design and performance.

Modeling 3E-S sustainable development problem by an ambiguous chance constrained optimization method

The environmental-energy-economic-social (3E-S) sustainable development problem aims to balance the environment, energy, and economy upon which human society critically relies. However, it is further complicated by various ambiguous input parameters about greenhouse gas (GHG) emissions, electricity consumption, gross domestic product (GDP), and unemployment rate. To address this complexity, this paper develops an ambiguous chance constrained optimization model with multiple chance soft constraints for optimizing the 3E-S sustainable development problem by strategically allocating labor across key sectors. Tractable formulations of the proposed model are derived by constructing three types of ambiguity sets for input parameters with ambiguous probability distributions. The first is to construct support-mean ambiguous distribution sets with little known information, the second is to extend support-mean ambiguity sets to mean-covariance ambiguity sets by incorporating interactive relationships among sectors, and the third is to extend support-mean ambiguity sets to inner-outer ambiguity sets with Wasserstein metric from globalized distributionally robust perspective. The availability and computability of the proposed model have been illustrated by planning India’s 3E-S sustainability for the year 2030. The results suggest that (i) the proposed method exhibits the capability to offer flexible policy measures; (ii) India should prioritize the development of the Mining and quarrying sector, the Transport, storage, communication, and services sector, and the Constructions sector; (iii) India needs to make greater efforts for promoting GDP while controlling GHG emissions and energy consumption; (iv) The policy measures and objectives are influenced by tolerance levels, support intervals, interactive relationships among sectors, globalized sensitivity, and Wasserstein ball size.

Effect of Grinding Conditions on Clinker Grinding Efficiency: Ball Size, Mill Rotation Speed, and Feed Rate

The production of cement, an essential material in civil engineering, requires a substantial energy input, with a significant portion of this energy consumed during the grinding stage. This study addresses the gap in the literature concerning the collective impact of key parameters, including ball size, feed rate, and mill speed, on grinding efficiency. Nine spherical balls, ranging from 15–65 mm, were utilized in six distinct distributions, alongside varying feed rates and mill speeds. ANOVA, Taguchi, and regression analyses were employed to explore their influence on grinding efficiency and cement properties. The findings revealed that ball size variation significantly affects grinding performance, with smaller diameter balls yielding higher efficiency due to increased abrasion and fine formation. Conversely, elevating mill speed generally diminishes grinding efficiency, particularly at speeds approaching 90% of the critical speed, impacting ball shoulder and foot angles. Moreover, increasing the feed rate affects the grinding performance differently based on ball distribution, with finer distributions experiencing adverse effects. Signal-to-noise ratios facilitated determining the optimal control factor levels to minimize energy consumption. Quadratic regression models exhibited strong predictive capabilities for energy consumption in grinding. Ultimately, the optimal grinding performance was achieved with Bond-type ball distribution No. 6, considering ball size, mill speed, and feed-rate interactions, albeit with considerations regarding grinding time and energy efficiency.

Improvement of mechanochemical leaching of zinc oxide ore — Optimization of grinding parameters for basket grinder

The mechanochemical leaching (MCL) process presents promising potential for efficiently extracting zinc from zinc oxide ores. This study analyzed the effects of several grinding parameters, including the agitator type, grinding ball size and material, grinding ball addition, and stirring speed, on the zinc leaching. Among them, the agitator type affects the flow form and mass transfer rate of the solution, the grinding ball size and material affects the crushing effect of the mineral powder, the grinding ball addition affects the state of motion of the grinding ball, and the stirring speed affects the grinding effect of the grinding ball on the mineral powder, which in turn affects the extraction of zinc. Experimental results show that optimization of these grinding parameters results in higher zinc leaching rates at lower energy costs. Under optimal conditions, the zinc leaching rate can reach 86.02% through the optimized MCL process, which is 9.38% higher than the conventional leaching process. Analysis techniques, such as XRD, particle size analysis, SEM-EDS, and EPMA, were utilized to examine leaching residues. The leaching mechanism of MCL process is derived under mechanical activation to destroy the insoluble product layer of zinc oxide ores (such as gangue), expose the zinc containing components, change the physical and chemical properties (such as mineral structure, particle size, and specific surface area), and enhance the reactivity of zinc oxide ore, and enhancing zinc leaching. The optimized MCL process offers the benefits of a straightforward process, reduced energy consumption, and eco-friendliness. This process has vast potential in the development and utilization of low-grade refractory zinc oxide ores in the Lanping area.

Effect of mechanochemical activation parameters on vanadium recovery from vanadium-bearing steel slag: Critical speed derivation for wet-ball milling

The existing equations in the literature for a mechanochemical activation (MA) critical speed proved that only the ball size, volumetric filling ratio, and the vial/bowl diameter influence the milling speed, thus these equations do not account for all other crucial parameters and the critical speed is constant for all the mechanochemical process parameters for every ball size, quantity powder and number of balls considered. Milling speed is one of the vital process parameters, thus this present work derived a novel equation that accounts for the influence of ball size, the ball-to-powder/slurry weight ratio (BPR/BSR), the mass of the mineral powder, the chemical solution, the inner diameter of the vail and the liquid-to-solid ratio (L:S). MA is very beneficial to the hydrometallurgical process and these parameters are key for an enhanced recovery of the desired metals from the mineral in question. The powder and the chemical solution are related by the liquid-to-solid ratio considered in the activation process, thus as the BPR increases for the ball sizes considered, the critical speed increases drastically. Also, the effect of ball size, milling time, and speed on the recovery efficiency of vanadium from vanadium-bearing steel slag (VBSS) was investigated. The VBSS powder was Na2CO3(aq)-milled with balls of varying size at different milling speeds and ignition/milling times. A mechanochemical activation leaching experiment was carried out for 10g VBSS; at a milling speed of 140 rpm, BPR 7.8/BSR 1.02, ball diameter 10 mm, L:S ratio 5:1, temperature 90 °C, and 30-min ignition time, the vanadium recovery efficiency of above 80 % was achieved. For every predetermined mass of VBSS powder and L:S ratio of the chemical solution concentration; the BPR/BSR and the size of the ball determine the critical speeds which in turn influence the leachability of the vanadium.

The influence of HKUST-1 and MOF-76 hand grinding/mechanical activation on stability, particle size, textural properties and carbon dioxide sorption

In this study, we explore the mechanical treatment of two metal–organic frameworks (MOFs), HKUST-1 and MOF-76, applying various milling methods to assess their impact on stability, porosity, and CO2 adsorption capacity. The effects of different mechanical grinding techniques, such as high-energy ball milling and hand grinding, on these MOFs were compared. The impact of milling time, milling speed and ball size during high-energy ball milling was assessed via the Design of Experiments methodology, namely using a 33 Taguchi orthogonal array. The results highlight a marked improvement in CO2 adsorption capacity for HKUST-1 through hand milling, increasing from an initial 25.70 wt.% (5.84 mmol g-1) to 41.37 wt.% (9.40 mmol g-1), marking a significant 38% increase. In contrast, high-energy ball milling seems to worsen this property, diminishing the CO2 adsorption abilities of the materials. Notably, MOF-76 shows resistance to hand grinding, closely resembling the original sample’s performance. Hand grinding also proved to be well reproducible. These findings clarify the complex effects of mechanical milling on MOF materials, emphasising the necessity of choosing the proper processing techniques to enhance their stability, texture, and performance in CO2 capture and storage applications.

Preparation of Humic Acid from Weathered Coal by Mechanical Energy Activation and Its Properties

Humic acid (HA) is rich in functional groups with high activity, which can effectively improve the soil environment. The large reserves of weathered coal in China provide sufficient raw material guarantee for HA extraction and utilization. At present, the activation side of weathered coal is still the main technical difficulty that restricts HA extraction. In this study, the weathered coal from Inner Mongolia was used as the raw material, and the mechanical energy was used to activate the weathered coal through a planetary ball mill, which improved the extraction rate of HA and optimized the molecular structure and composition of HA. The effects of four parameters, namely, ball material ratio, ball milling time, ball milling speed, and ball size, on the free HA content of weathered coal were investigated, the HA was extracted by alkaline extraction method, and the activated weathered coal and the extracted HA were characterized. The results showed that a ball material ratio of 9:1, a ball milling speed of 200 r/min, a ball milling time of 200 min, a milling ball size of Ф5:Ф10:Ф15 = 48:42:45 and 56:42:37 are the optimal parameters for the mechanical energy activation, and the HA extraction rate of activated weathered coal under these conditions reached 82.3%, which was 15% higher than that of the unactivated one. Moreover, the aroma of the ball-milled weathered coal increased, the content of oxygenated functional groups increased, and the molecular weight and aroma of HA increased. This provides scientific theoretical guidance for the preparation of HA with high aromaticity and large molecular weight from weathered coal.

Performance optimization and comparative study of a conical solar distiller with optimized construction of aluminium balls as energy storage materials

This study seeks to find the ideal size of aluminum balls to improve the effectiveness of conical solar stills for storing energy, due to the increasing demand for drinking water and the high costs of getting portable drinking water. To achieve this, three comparable conical solar distillers were made using aluminum balls of various diameters (1 cm, 1.5 cm, 2 cm, and 2.5 cm) at a 4 cm center spacing. Two days were spent on the experiments. The first distiller had no metal balls on the first day, whereas the second and third had 41 1 cm and 1.5 cm aluminum balls uniformly dispersed at the bottom. On the second day, the first distiller had no metal balls, but the second and third had 41 2 cm and 2.5 cm balls. The water basin depth was consistently maintained at 2.5 cm. The results revealed that the distiller with 2 cm diameter aluminum balls achieved the highest productivity, yielding 840 mL/m2, compared to the distillers with aluminum balls of 1 cm, 1.5 cm, and 2.5 cm diameter, as well as the conventional distiller without any storage materials, which yielded 645 mL/m2, 695 mL/m2, 755 mL/m2, and 570 mL/m2, respectively. The ideal diameter for the aluminum balls was found to be 2 cm, leading to a significant 47.37 % enhancement in water productivity. Conical solar stills using 2 cm diameter aluminum balls as an economical energy storage material provide the best answer.

Wet mechanochemical surface modification of calcite employing an integration of conventional design and analytical hierarchy process

The demand for ultra-fine mineral powders from various industries requires the applications of wet grinding and surface modification. In this study, wet mechanochemical surface modification of micronized calcite (d50 = 4.92 μm) with stearic acid [CH3(CH2)16COOH] was carried out in a planetary ball mill. The seven parameters were specified: ball filling ratio (%), ball size distribution ratio (10 and 15 mm, %), micronized calcite filling ratio (%), pulp solid ratio (wt%), mill speed (rpm), stearic acid dosage (% of micronized calcite) and modification time (min). Then, these parameters were optimized using a conventional experimental design when maximizing the active ratio (%) as a significant value for coated calcite. Besides, the analytical hierarchy process was applied to observe the importance of each parameter. Stearic acid dosage, mill speed, and micronized calcite filling ratio are the top three parameters affecting the active ratio. Next, size distribution, XRF, XRD, SEM, FTIR, TGA-DTA, contact angle, and whiteness measurements were performed on the micronized calcite (MC) and coated micronized calcite (CMC) samples. The final CMC product had a 99.90% active ratio, 2.49 μm mean (d50) particle size, and 101.66o contact angle. Finally, CMC obtained by the surface modification can be used as a filler mineral.

Unveiling ball size heterogeneity effect on microwave absorption properties of cobalt

Recent advances in material science have led to impressive microwave absorbing materials, yet their practical applications are hindered by complex synthesis processes. This study explores a cost-effective alternative, emphasizing modifying material morphology using ball size heterogeneity. Unlike using same-sized balls, employing different-sized balls maximizes collision energy, yielding finer particles. In this study, the effect of ball size heterogeneity on microwave absorption performance has been investigated for the first time. An attempt has been made to explore how using ball size heterogeneity changes structural, magnetic, and dielectric properties of cobalt (Co) and how these modifications affect material's absorption properties. Results show that by using ball size heterogeneity, the particle size distribution in 0.1–1 μm range has been increased, yielding much finer particles. The relative permittivity value also increases due to changes in average particle size and surface area. Microwave absorption characteristics of Co milled with different-sized balls showed a significant change. A 15 h milled Co sample using different-sized balls achieved an effective bandwidth of 9.65 GHz (4.75–14.4), contrasting with no absorption bandwidth when using same-sized balls, with a 2 mm coating thickness. This work provides new insights into preparing materials for microwave absorption applications using ball milling method.

Preparation and properties of liquid-core yogurt balls by layer-by-layer assembly of edible packaging materials

Abstract To address the issue of yogurt adhering to the inner walls of packaging, resulting in resource wastage, a controllable particle size of alginate-calcium yogurt liquid core ball (LC-Yoba) was prepared using a mold-reverse spherification method. The effectiveness of layer-by-layer (LBL) assembly techniques in enhancing the performance of LC-Yoba was investigated. The results showed that a multilayer structure composed of beeswax-chitosan (BW-CS) was successfully assembled on the surface of LC-Yoba, wherein the number of assembly layers significantly impacts its performance. Compared with the unassembled LC-Yoba, the bursting force of the assembled three layers of LC-Yoba increased by 194.67 %, the elasticity increased by 19.76 %, and the weight loss rate decreased by 86.58 %. In addition, the appearance of the three layers of LC-Yoba and the pH, acidity, and water holding capacity of the yogurt were maintained in a stable state within 72 h at room temperature.

Surface nano crystallization and nitriding on microstructure and properties of 304J1 stainless steel

To improve the mechanical and antibacterial properties of 304J1 stainless steel, hybrid surface treatments, which include nitriding combined with shot peening operations, are used. Shot peening with different sizes of steel balls makes the material’s surface nanocrystalline, providing more diffusion channels for subsequent nitrogenating, and the nitriding efficiency is improved. Nitrogen cannot only improve the antibacterial property but also significantly enhance the strength of 304J1. The experimental results show that within a certain depth, the surface of 304J1 can be nanosized by shot peening for 20 min with a projectile diameter of 0.2 mm. The depth of the nitriding layer reaches 0.6 um, the surface hardness increases from 560 HV to 1100 HV, and the antibacterial property against Escherichia coli increases from 10% to 85%.

Effect of Ball Milling Conditions on the Microstructure and Dehydrogenation Behavior of TiH2 Powder

This study investigated the effects of revolution speed and ball size in planetary milling on the microstructure and dehydrogenation behavior of TiH2 powder. The particle size analysis showed that the large particles present in the raw powder were effectively refined as the revolution speed increased, and when milled at 500 rpm, the median particle size was 1.47 m. Milling with a mixture of balls of two or three sizes was more effective in refining the raw powder than milling with balls of a single size. A mixture of 3-mm and 5-mm-diameter balls was the optimal condition for particle refinement, and the measured median particle size was 0.71 m. The dependence of particle size on revolution speed and ball size was explained by changes in input energy and the number of contact points of the balls. In the milled powder, the endothermic peak measured using differential thermal analysis was observed at a relatively low temperature. This finding was interpreted as the activation of a dehydrogenation reaction, mainly due to the increase in the specific surface area and the concentration of lattice defects.

The influence of different load distribution considering geometric error on the fatigue life of ball screw

The ball screw pair is a precision drive component that converts rotary motion into linear motion. In practical applications, because the feed system usually has rotational torque and geometric errors, it may increase the contact load of the ball screw pair and reduce the fatigue life. In order to study the influence of different loads and geometric errors on the maximum contact load and fatigue life of ball screw pairs, the following research work was carried out. Firstly, based on the composite load and rotational torque, the ball load distribution model is established, and the accuracy of the model is verified by finite element modeling analysis. Then, the influence of different composite loads, rotation times and geometric errors (including ball size error, lead error and raceway tooth profile error) on the ball load distribution is analyzed. Finally, the influence of compound load, rotating torque and geometric error on the fatigue life of ball screw pairs is studied. The results show that the rotational torque and lead error have a great influence on the load distribution and fatigue life of the ball, and the influence of lead error on load distribution is greater than that of dimension error and tooth profile error. The fatigue life of the ball screw pair with non-uniform load distribution is shorter than that of the ball screw pair with uniform load distribution.

The Curious Case of a 'Maverick' Cementoblastoma!

The Cementoblastoma is a benign ectomesenchymal odontogenic neoplasm of the jaw, arising from an exuberant production of cemental tissue continuous with the roots of teeth (usually mandibular posteriors), resulting in a calcified mass adherent with the root apices. A curious case of a large Cementoblastoma, the size and shape of a ping pong ball, is presented, the first of its kind ever reported to involve the internal / medial / lingual aspect of the mandible, and presenting with unusual and deviant features. The Cementoblastoma is usually associated with certain inherent and pathognomonic features, making it rather straightforward to identify and diagnose. Strikingly uncharacteristic clinical, radiographic and histologic attributes presented in this case, made this 'out of the ordinary' and 'Maverick'-like Cementoblastoma, arduous to diagnose, nevertheless, making it an interesting, informative and curious Case Study. This report has brought to light for the first time, several new facets of the Cementoblastoma.

Phase field modeling of crack propagation in three-dimensional quasi-brittle materials under thermal shock

Quasi-brittle materials create intricate crack patterns on their surface and internal three-dimensional crack networks when exposed to thermal shock conditions. Their cracking behavior is notably impacted by their quenching temperature and size. In this paper, a coupled three-dimensional phase field-cohesive zone model that accounts for thermoelastic fracture is developed to reproduce the quenching and cracking experiments of ceramic balls. The accuracy of the phase field model is demonstrated by simulating the phase field of a single-element cooling process and comparing it with the analytical solution. The quench fracture process of the 3D ceramic ball is then simulated. The phase field simulations show that the surface crack morphology during the quenching process is somewhat random. Still, the crack distribution density is determined by the quenching temperature difference and ceramic ball size. Furthermore, a threshold size is present during the quenching process. When the ceramic ball's radius falls below this threshold, the surface crack pattern no longer appears during quenching. Consequently, the phase-field-cohesive zone model represents an effective means of predicting three-dimensional fracture processes in quasi-brittle materials subjected to thermodynamically coupled loading.