Search

Study Design. Retrospective case series. Objective. To characterize failure rates of cervical cages based on manufacturer and design characteristics using the nationwide database of reported malfunctions. Background. The Food and Drug Administration (FDA) aims to ensure the safety and efficacy of cervical interbody implants postimplantation; however, intraoperative malfunctions may be overlooked. Materials and Methods. The FDA's Manufacturer and User Facility Device Experience database was queried for reports of cervical cage device malfunctions from 2012 to 2021. Each report was categorized based on the failure type, implant design, and manufacturer. Two market analyses were performed. First, "failure-to-market share indices" were generated by dividing the number of failures per year for each implant material by its yearly US market share in cervical spine fusion. Second, "failure-to-revenue indices" were calculated by dividing the total number of failures per year for each manufacturer by their approximate yearly revenue from spinal implants in the US. Outlier analysis was performed to generate a threshold value above which failure rates were defined as greater than the normal index. Results. In total, 1336 entries were identified, and 1225 met the inclusion criteria. Of these, 354 (28.9%) were cage breakages, 54 (4.4%) were cage migrations, 321 (26.2%) were instrumentationrelated failures, 301 (24.6%) were assembly failures, and 195 (15.9%) were screw failures. Poly-ether-ether-ketone implants had higher failure by market share indices for both migration and breakage compared with titanium. Upon manufacturer market analysis, Seaspine, Zimmer-Biomet, K2M, and LDR exceeded the failure threshold. Conclusion. The most common cause of implant malfunction was breakage. Poly-ether-ether-ketone cages were more likely to break and migrate compared with titanium ones. Many of these implant failures occurred intraoperatively during instrumentation, which underscores the need for FDA evaluation of these implants and their accompanying instrumentation under the appropriate loading conditions before commercial approval. [ABSTRACT FROM AUTHOR]

Deformable gel particles (DGPs) possess the capability of deep profile control and flooding. However, the deep migration behavior and plugging mechanism along their path remain unclear. Breakage, an inevitable phenomenon during particle migration, significantly impacts the deep plugging effect. Due to the complexity of the process, few studies have been conducted on this subject. In this paper, we conducted DGP flow experiments using a physical model of a multi-point sandpack under various injection rates and particle sizes. Particle size and concentration tests were performed at each measurement point to investigate the transportation behavior of particles in the deep part of the reservoir. The residual resistance coefficient and concentration changes along the porous media were combined to analyze the plugging performance of DGPs. Furthermore, the particle breakage along their path was revealed by analyzing the changes in particle size along the way. A mathematical model of breakage and concentration changes along the path was established. The results showed that the passage after breakage is a significant migration behavior of particles in porous media. The particles were reduced to less than half of their initial size at the front of the porous media. Breakage is an essential reason for the continuous decreases in particle concentration, size, and residual resistance coefficient. However, the particles can remain in porous media after breakage and play a significant role in deep plugging. Higher injection rates or larger particle sizes resulted in faster breakage along the injection direction, higher degrees of breakage, and faster decreases in residual resistance coefficient along the path. These conditions also led to a weaker deep plugging ability. Smaller particles were more evenly retained along the path, but more particles flowed out of the porous media, resulting in a poor deep plugging effect. The particle size is a function of particle size before injection, transport distance, and different injection parameters (injection rate or the diameter ratio of DGP to throat). Likewise, the particle concentration is a function of initial concentration, transport distance, and different injection parameters. These models can be utilized to optimize particle injection parameters, thereby achieving the goal of fine-tuning oil displacement. [ABSTRACT FROM AUTHOR]

Background: The advent of three‐dimensional (3D)‐printed custom‐made implants has revolutionized orthopaedic surgery, particularly in limb‐ and joint‐sparing surgeries. However, clinical experience in the revision for 3D‐printed implant breakage is lacking, and the revision surgery remains challenging. This study reported the revision of proximal tibial prosthetic reconstruction necessitated by solid‐body breakage of a 3D‐printed implant, aiming to detail the surgical techniques and evaluate postoperative outcomes. Case Presentation: A patient diagnosed with osteosarcoma underwent joint‐sparing surgery with a 3D‐printed implant, but implant breakage occurred during subsequent follow‐up. The initial implant was broken into two parts: the proximal implant breakage part (IBP) integrated with the host bone and the distal IBP left in the prosthetic component. Four revision protocols were devised, each based on one of the four hypothesis results of taking out the initial implant. A new custom‐made implant and a series of assistance devices ("positioning devices," "drill devices," "tap devices," and "separator devices") were specifically prepared for revision surgery. The proximal IBP was taken out from the host bone, but the distal IBP was not taken out from the initial prosthetic component. The patient received the new custom‐made implant for reconstruction, with the knee joint preserved. The patient recovered uneventfully after revision surgery and achieved satisfactory function. The Musculoskeletal Tumor Society was 28 at the last follow‐up. No complications were detected during the follow‐up period. Conclusion: Comprehensive preoperative planning and preparation, enabling the surgeon to effectively address intraoperative challenges, are crucial for the successful revision of 3D‐printed implant breakage. It is feasible to re‐implant a 3D‐printed custom‐made implant, demonstrating satisfactory clinical and functional results. [ABSTRACT FROM AUTHOR]

Study Design. A retrospective case series. Objective. This study aims to assess the rates of lumbar interbody cage failures based on their material and manufacturer. Summary of Background Data. Perioperative lumbar interbody cage malfunctions are underreported events in the spine literature and may result in complications. Although the Food and Drug Administration ensures the safety of these devices under physiological conditions after implantation, these devices may experience nonphysiological conditions during implantation, which may be overlooked. Materials and Methods. The MAUDE database was examined for reports of lumbar cage device malfunctions from 2012 to 2021. Each report was categorized based on failure type and implant design. A market analysis was performed by dividing the total number of failures per year for each manufacturer by their approximate yearly revenue from spinal implants in the United States. Outlier analysis was performed to generate a threshold value above which failure rates were defined as greater than the normal index. Results. Overall, 1875 lumbar cage malfunctions were identified. Of these, 1230 (65.6%) were cage breakages, 257 (13.7%) were instrument malfunctions, 177 (9.4%) were cage migrations, 143 (7.6%) were assembly failures, 70 (4.5%) were screw-related failures, and 21 (1.1%) were cage collapses. Of the breakages, 923 (74.9%) occurred during insertion or impaction and 97 entries detailed a medical complication or a retained foreign body. Of the migrations, 155 (88.6%) were identified postoperatively, of which 73 (47.1%) detailed complications and 52 (33.5%) required a revision procedure. Market analysis demonstrated that Medtronic, Zimmer Biomet, Stryker, Seaspine, and K2M exceeded the calculated threshold. Conclusions. Lumbar cages with polyether ether ketone core material failed more frequently by breakage, whereas titanium surface cages failed more frequently by migration. Failure rates varied depending on the manufacturer. Most cage breakages identified in the present study occurred intraoperatively during implantation. These findings call for a more detailed Food and Drug Administration evaluation of these intraoperative malfunctions before commercial approval. [ABSTRACT FROM AUTHOR]

During fluvial transport pebbles are subject not only to abrasion but also to breaking. Pebbles from the river Ammer (mostly carbonate rocks) show that breaking is a frequent and essential event. Due to frequent breaking, pebbles of carbonate rocks rarely attain a symmetrical final shape (spheroid). Crystalline rocks without schistosity break less frequently, hence spheroids are more frequent. [ABSTRACT FROM AUTHOR]

Particle breakage plays a crucial role in determining the macroscopic mechanical behaviors of granular materials, such as compressibility and shear strength. This study aims to investigate the mechanical behavior and particle shape evolutions of three types of granular materials, namely Leighton Buzzard sand (LBS), glass bead (GB), and carbonate sands (CSs), through a series of 1D compression tests. The study employs micro-computed tomography (micro-CT), image processing, and analysis techniques to build a comprehensive fragmentation database and elucidate the statistical mechanical behavior of granular materials. A set of samples were prepared for each granular material type and compressed to a desired stress level. The compressed samples and natural sand particles were then scanned using micro-CT, and the irregular particle morphologies were reconstructed through a series of image processing techniques. By analyzing the particle size distributions and the evolutions of the particle shape, a detailed comparison between the LBS, GB, and CS particles was conducted. The study reveals that the mechanical behavior and fracture patterns of granular materials are influenced by the initial particle morphology and mineralogy. The CS particles, which exhibit abundant intra-particle pores and irregular morphology, have lower compressive strength and higher compressibility compared to LBS and GB particles. Furthermore, the study finds that the particle size of the newly generated fragments for LBS, GB, and CS particles is primarily concentrated around 0.3 mm, 0.65 mm, and 0.18 mm, respectively, indicating significant differences in the particle failure modes between them. The statistical analysis of the newly generated fragments provides quantitative results that help us better understand the development of particle breakage and gain deep insights into the role of grain shape in the mechanical behavior of granular materials. [ABSTRACT FROM AUTHOR]

Much of the debate in archaeological theory throughout the last decades has revolved around challenging problematic humanist principles that have shaped our discipline, particularly the idea that humans are masters over nature. Postprocessualists sought, among other things, to emancipate the human condition from this essentialist claim in part by exposing the historical and cultural situatedness of this humanist principle – an epistemological endeavour. In comparison, posthumanists have animated the material world (albeit in different ways) to decentre human beings in relation to long-forsaken nonhumans – an ontological agenda. While posthumanists accuse postprocessualists of practicing anthropocentrism and the latter accuse the former of occupying an ahumanist and anti-epistemological position, there are powerful commonalities in their critique of late humanist doctrines. The aim of this paper is to introduce a theory that exposes the illusory humanist claim of human control over nature and to recognise other forces with momentum besides human will, while at the same time giving prominence to questions about human knowledge and practice. Therefore, a connection is formed between postprocessualism and posthumanism and, as an ironic result, a theory of breakage is formulated. When we consider human participation with breakage, defined as those continuous and uncontrollable phenomena involving the unbinding of object form, we come to terms with a different form of anthropological understanding termed 'the social knowledge of breakage'. This constitutes an embodied form of knowledge, which is acquired and expressed practically from a young age about how objects break and how one must respond to these situations. This knowledge is exposed in both mundane and ceremonial practices, in linguistic and non-linguistic forms, shaping social practices in uncertain ways, and can be analysed according to three different strands. In this way, we become aware of the creative ways in which broken materials inadvertently affect our practices. [ABSTRACT FROM AUTHOR]

Breakage, Helmholtz free energy, and nonlinearity are involved in many fundamental phenomena of complex systems across natural sciences. However, a mathematical equation that can express the entire life cycle of complex natural objects (such as rock-like quasi-brittle materials) is lacking. We expand the material body system to an isolated compound thermodynamic system to establish an innovative theoretical model induced by coupling nonlinear separation of Helmholtz free energy and breakage evolution that can be used to express the extreme entire life model of rock under unequal amplitude loading and unloading cycle. We gain crucial insights into the life essence of limestone, which is termed "Negative Dissipation." This study first shows that the change in the mechanical properties of quasi-brittle materials caused by the timely evolution of breakage can be represented by the nonlinear separation of Helmholtz free energy and negative dissipation. An analytical solution to the nonlinear separation variables of Helmholtz free energy is provided by combining the method of solving nonlinear partial differential equations in mathematics and thermodynamic law. An analytical solution of Helmholtz free energy considering nonlinearity and breakage is proposed, and an equation that can reflect the constitutive mechanics law of the entire life cycle of rock in the theoretical model is presented. Theoretical results are consistent with the experimental data obtained from limestone samples with different prefabricated cracks. This original study provides a theoretical foundation for the life model of complex natural objects for nonlinear breakage and an early warning investigation of rocks under various unprecedented conditions. This study first found that the change in the mechanical properties of complex natural objects caused by the timely evolution of breakage can be represented by the nonlinear separation of Helmholtz free energy. We establish an innovative theoretical model induced by coupling nonlinear separation of Helmholtz free energy and breakage evolution. The innovative theory includes three parts: (1) an analytical solution to the nonlinear separation variables of Helmholtz free energy, (2) an analytical solution of Helmholtz free energy considering nonlinearity and breakage, and (3) an equation of the theoretical model that can reflect the constitutive mechanics' law of the entire life of quasi-brittle rocks is presented for the first time. This original research result provides the foundation for a more in-depth life cycle of quasi-brittle rocks to develop the theoretical basis for the nonlinear breakage and early warning research of materials under various unprecedented conditions. We report a route to material microstructure composition, which may open an alternative pathway to quasi-brittle materials, which may, in turn, open a door into the mysterious world of science. [ABSTRACT FROM AUTHOR]

The Discrete Element Method (DEM) has become increasingly popular for simulating breakage operations and grinding equipment performance. Two main breakage approaches can be found in literature: bonded particle models and particle replacement models. This work is focused on fitting the parameters of a DEM particle replacement breakage model for maize, implemented in software Rocky DEM. Once all required experimental and calibration procedures were developed for maize specific DEM properties and parameters, single particle compression tests were carried out to fit the parameters of the breakage model, which was extensively analyzed for validating its capability of representing the material. Maize properties showed to be in agreement with literature sources. Compression tests simulated in DEM led to the same results as their experimental counterparts, validating the model's capability of representing maize breakage. These results are the basis for further simulation of a full milling process in a hammer mill. [Display omitted] • Maize breakage in DEM is addressed by a particle replacement model. • Parameters are fitted based on single particle compression tests. • The breakage model is validated by means of DEM simulations. • DEM successfully predicts maize kernels' breakage. • The breakage model can be used in simulations of a complete maize milling process. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of initial values of soil mean grain size ( d 50 0 ) and soil uniformity coefficient ( C u 0 ) on the one-dimensional compression behavior of granular soils. Soil samples consisting of equant-shaped, calcerous origin, crushed individual grains with a grain size range of 2.00–25.00 mm were examined in the laboratory tests. The yield stress, the initial and final stresses of the virgin compression line (VCL), and the hardening stress of soil samples during one-dimensional compression behavior were determined. Results indicated that an increase in the soil’s initial mean grain size and a decrease in the soil’s initial uniformity coefficient led to an increase in the value of these oedometric stresses. Soil samples reached the virgin compression line at an axial deformation ε a V C L - i of 10–13% and passed this line at an axial deformation ε a V C L - f of 26–30%. It was observed that the instantaneous index void ratio values e min i and e max i of the soil samples decreased linearly with a slope α e of 0.10 in the e - ln σ V plane during one-dimensional compression. The curve of the soil’s instantaneous minimum void ratio e min i values during one-dimensional compression was proposed as a lower boundary for the one-dimensional compression curve of granular soils. [ABSTRACT FROM AUTHOR]

Wire electric discharge machining (WEDM) is a widely used high-precision machining process. It has the capability of cutting high-strength alloys, namely, tool alloys, Hastelloy, and monel with very tight tolerance. Frequent wire breakage adversely affects the product geometric precision, surface integrity, and productivity of the manufacturing establishments. It is essential to understand the causes of wire breakage and to mitigate the frequency of its occurrence. This paper comprehensively reviews the experimental as well as theoretical research work reported on various aspects of wire electrode erosion such as the effect of heat generated in spark plasma, thermal stresses, wire rupture phenomena, and wire fatigue. It also presents important research findings on the causes of wire failure and advancements to reduce wire erosion and wire vibrations. The paper systematically and carefully examines the measures suggested to improve the wire life and depicts the development of various wire health monitoring and control systems. Overall, it presents useful insights and important guidelines for the efficient utilization of the wire EDM process by mitigating the causes of wire erosion and its failure. It will certainly help for the improvement of the precision machining capability of the WEDM process. [ABSTRACT FROM AUTHOR]

The quality of grains and food after drying remains the subject of much research due to the development of thermal and hydro-sensitive tensions, as well as undesirable chemical and biochemical changes that can occur during drying. Determining the dynamics of the level of grain damage during drying remains highly complex from an experimental point of view. This work proposes a novel system dynamics-based modelling approach to quantifying the percentage of product breakage during drying in fluidised bed dryers. A simple and robust method based on causal relationships and flux diagrams was developed to describe the dynamics of drying and product quality. The model was then compared with experimental data from the literature for fluidised bed dryers and breakage indices. A sensitivity analysis of the model input parameters was performed, showing their effects on moisture content, product temperature, drying rates and product quality. Finally, unrestricted and restricted optimisation scenarios for breakage levels and relative inlet humidity were presented. The final use of the product, dryer capacity and the existence of time constraints are integral to determining the optimum dryer operation point. The proposed methodology can be used for different products and expanded for different dryer configurations. This work should provide a better understanding of the drying process and optimise fluidised bed dryers to maximise quality. • A novel model to analyse grain quality in fluidized dryers is presented. • Model was calibrated and validated with excellent agreement. • Optimisations performed from different objectives of drying operations. • High grain moisture content & elevated drying temperatures showed higher breakages. • Dryer capacity and time constraints crucial for minimising grain damage. [ABSTRACT FROM AUTHOR]

The approach outlined in this paper takes advantage of the existence of stationary states and similarity solutions to reduce a one-dimensional population balance model with particle volume as the internal dimension from a partial integro-differential equation to a single ordinary differential equation for the evolution of the mean size. The mechanisms of accretional growth, collisional growth and breakage, either individually or in all possible combinations, are considered. Power-law rate kernels are employed and a self-similar fragment distribution is assumed for the breakage term. When expressed in terms of the evolution of the scaled number-mean particle volume, the model parameters consist of kernel orders and the characteristic times associated with each mechanism. Equations for the scaled moments of the stationary states and similarity solutions are exhibited for all possible mechanism combinations as are equations for the trajectories of scaled number-mean particle volume. Stability of the stationary states and similarity solutions is addressed in an appendix. It should be clear that when this level of simplification is possible, the subject of population balance modeling becomes considerably easier to teach while its use becomes much easier to promote in industry. The use of this simplified approach for extraction of model parameters from experiment is demonstrated in an example, followed by a brief discussion of using the results for scale up. To close out the paper, the same approach, but now in two internal dimensions (particle volume and surface area), is used to demonstrate the capability of the model to unify a set of operating conditions for carbon black manufacture across multiple grades and two different types of synthesis reactors. This is done by extracting the characteristic coalescence time at multiple temperatures and correlating the results in an Arrhenius plot. The model matches known values of primary particle size, and predicts a key indicator of the product's fractal aggregate structure, namely the number of primary particles per aggregate. The model results are then pushed to yield insight into the nature of the possible collision and coalescence mechanisms. [Display omitted] • Similarity solutions/stationary states enable reduction of 1-D models to a single ODE for mean size evolution. • Distribution shape is expressed in the form of scaled moments that are constant under these conditions. • Certain of these combine with the rate kernels to identify characteristic timescales. • These simplifications enable extraction of rate kernel orders and timescales from data. • These 1-D model simplifications are extended to a 2-D collision-coalescence example. [ABSTRACT FROM AUTHOR]

[Display omitted] • Weakly cohesive Chitosan microcapsules were deformed up to breakup in an extensional flow with orthogonal observations. • Two mechanisms of rupture regimes of microcapsules were revealed: fluid-like and solid-like behaviours. • The dual response of microcapsule rupture in flow is closely correlated to the shell structure. The controlled rupture of a core–shell capsule and the timely release of encapsulated materials are essential steps of the efficient design of such carriers. The mechanical and physico-chemical properties of their shells (or membranes) mainly govern the evolution of such systems under stress and notably the link between the dynamics of rupture and the mechanical properties. This issue is addressed considering weakly cohesive shells made by the interfacial complexation of Chitosan and PFacid in a planar extensional flow. Three regimes are observed, thanks to the two observational planes. Whatever the time of reaction in membrane assembly, there is no rupture in deformation as long as the hydrodynamic stress is below a critical value. At low times of complexation (weak shear elastic modulus), the rupture is reminiscent of the breakup of droplets: a dumbell or a waist. Fluorescent labelling of the membrane shows that this process is governed by continuous thinning of the membrane up to the destabilization. It is likely that the membrane shows a transition from a solid to liquid state. At longer times of complexation, the rupture has a feature of solid-like breakup (breakage) with a discontinuity of the membrane. The maximal internal constraint determined numerically marks the initial location of breakup as shown. The pattern becomes more complex as the elongation rate increases with several points of rupture. A phase diagram in the space parameters of the shear elastic modulus and the hydrodynamic stress is established. [ABSTRACT FROM AUTHOR]

In fluidized beds, particle-particle and particle-wall collisions eventually lead to the breakage of particles. The purpose of this study was to simulate the breakage of non-spherical rod-shaped particles in a pseudo-2D fluidized bed. A coupled computational fluid dynamics and discrete element method was adopted for simulations. Non-spherical particles were created using the multi-sphere method and the quaternion concept, and three breakage scenarios were considered. The effect of inlet gas velocity and size of particles on particles breakage rate and the impact of breakage phenomenon on the bed height were examined. Also, the number of broken particles in each scenario and breakage location were investigated. It was observed that the breakage phenomenon is more severe at the beginning of simulation, and its intensity decreases over time. In addition, the height of the bed increases by passing the time and increasing the number of smaller particles. Furthermore, breakage rate is directly related to the diameter of constituent spheres of particles and fluidization gas velocity, and also most breakages occur near the bed wall. [Display omitted] • CFD-DEM simulation of the non-spherical particles breakage. • Using the multi-sphere method employing quaternions. • Investigation of the breakage rate at different velocities/diameters. • Investigating the three different breakage scenarios. • Investigating the breakage at different bed zones. [ABSTRACT FROM AUTHOR]

The change in the viscosity of starch and polymer sizing compositions depending on the cooking temperature was studied. A change in the temperature of gelatinization and the achievement of the maximum viscosity of the starch and the developed composition were revealed. It has been established that the breaking load and elongation of the sized yarn mainly depend on the type of dressing. [ABSTRACT FROM AUTHOR]

The basic model for agglomerate breakage under the effect of hydrodynamic stress (dmax = C.G−γ) is only applicable for low velocity gradients (<500 s−1) and is often used for shear rates that are not representative of the global phenomenon. This paper presents a semi-empirical model that is able to predict mean floc size in a very broad shear range spanning from aggregation to floc fragmentation. Theoretical details and modifications relating to the orthokinetic flocculation output are also provided. Modelling changes in turbidity in relation to the velocity gradient with this model offer a mechanistic approach and provide kinetic agglomeration and breakage index ka and kb. The floc breakage mode is described by the relationship between the floc size and the Kolmogorov microscale. Shear-related floc restructuring is analysed by monitoring the fractal dimension. These models, as well as those used to determine floc porosity, density and volume fraction, are validated by the experimental results obtained from several flocculation operations conducted on ultrafine kaolin in a 4-litre reactor tank compliant with laws of geometric similarity. The velocity gradient range explored was from 60 to 6000 s−1. [ABSTRACT FROM AUTHOR]

Attrition and breakage of agglomerates are prevalent during production and handling processes in many industries. Therefore, it is highly desirable to be able to model and analyse the agglomerate breakage process under various loading conditions. The ensemble strength and breakage patterns of agglomerates are still not well understood despite a significant amount of research being carried out. In this study, three-dimensional discrete element method (DEM) simulation of the impact breakage behaviour of agglomerates were performed using a Timoshenko beam bond model which considers axial, shear, twisting and bending behaviours on the bonds. An advantage of the Timoshenko beam bond model is the pertinent parameters of the bond contact have clear physical meaning and therefore could be determined through corresponding experimental characterisations. The mechanical properties of the bonds in this study were firstly calibrated using experimental measurements. The validation of the Timoshenko beam bond model was then undertaken by direct comparisons between the numerical simulation and experimental results of impact tests. It was shown that the time evolution of the agglomerate breakage process obtained from simulation had good agreement with experimental observations. Numerical results indicate that most of the damage happens at the early stage of the impact and a cone shape fracture zone is formed quickly inside the agglomerate where strong compressive stresses are concentrated. It is found that the exterior of the fracture zone is surrounded by an arch shape tensile stress which dominates the fracture propagation. [ABSTRACT FROM AUTHOR]

The shape of granular materials is one of the effective parameters in determining mechanical behavior. This property affects the fracture strength, compressibility, maximum friction angle and the distribution of contact stresses. So far, laboratory studies on the effect of shape on the behavior of granular materials have focused mostly on comparing the results of angular and rounded grains. Due to the distribution of different shapes in natural grain materials, experimental studies of the effect of sphericity index are of great importance. On the other hand, it is necessary to investigate the grain shape on the compression model parameters comprehensively. Therefore, based on the energy conservation equation and the use of statistical Weibull and fractal theory, the compressibility model of granular materials under uniaxial loading conditions is obtained by taking into account the quantitative parameters related to the shape of grain. Then, in order to evaluate the analytical model, three stages of laboratory tests are performed. In the first stage, uniaxial loading tests are performed on four different shapes of concrete grains of the same size under the same conditions. In the second stage, similar experiments are performed on angular granite grains to check the applicability of the model to natural materials with different shapes. In the third stage, the sleeper loading modeling is performed on granite grains of real ballast dimensions. The results of large-scale tests are compared with the compressibility model obtained from the results of small-scale tests. Finally, an empirical relationship is proposed to determine the amount of breakage factor based on the energy applied to the grains. The results show that the empirical relationship in combination with the analytical solution can accurately predict the stress-breakage-void ratio behavior of granular materials at each loading step. [ABSTRACT FROM AUTHOR]

Particle breakage and abrasion of aggregate materials can be induced by field compaction during construction, which adversely affects their mechanical properties. However, current compaction quality control testing does not evaluate changes in particle size distribution and particle morphology of aggregate materials due to the lack of fast and inexpensive testing methods. In this study, a modified watershed-based segmentation image analysis method and computational geometry algorithms were used to quickly quantify changes in particle size and morphology distributions of a large amount of contacting aggregate particles. The accuracy and required minimum sample size of the image analysis method were statistically evaluated. Compared to the conventional ASTM C136 aggregate sieve analysis test, the image analysis method conducted on a 40% sample size of the conventional method yielded less than 6% difference between the results, which can meet the ASTM C136 test repeatability criteria. In addition, demonstration tests were conducted to incorporate the image analysis method into a laboratory vibratory compaction test for evaluating the overall particle size and morphology changes of an aggregate material after compaction. Results indicate that the initial gradation and water content of the aggregate material can influence the particle breakage and abrasion characteristics of aggregate materials under compaction. • An image-based compaction testing method is proposed to evaluate aggregate particle breakage and abrasion under compaction. • Repeatability of the image analysis method for separating particles in contact and determining particle size is evaluated. • The method for determining changes in morphology distributions of an aggregate after vibratory compaction is demonstrated. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms governing the interaction of high-velocity projectiles and sand targets is important for numerous applications and industries. The high-velocity penetration of sand targets is known to be controlled by micromechanical phenomena; however, our quantification of these phenomena and our understanding of water saturation effects on target response is presently limited. To help improve our understanding of these phenomena, we performed impact experiments on wet and dry sand with in-situ and post-mortem analysis in a two-stage gas gun with varying impact chamber pressures. For in-situ analysis, we developed and used a novel experimental method for measuring projectile depth and three-dimensional displacement fields from orthogonal flash X-ray images acquired during the penetration process. We also employed in-situ high-speed imaging of ejecta. For post-mortem analysis, we examined final depths of penetration, particle size distributions, and permanent penetrator deformation. We found that impacts into wet sand targets featured enhanced sand displacements around projectiles, enhanced ejecta, and enhanced intermediate and final depths of penetration as compared to impacts into dry targets. We also found that impacts into wet targets led to less particle breakage than impacts into dry targets. Target chamber pressure was found to significantly influence final depth of penetration, likely through a fluidization process as air and fluid escaped the sample's pores to equilibrate with the surrounding chamber pressure after initial impact. We discuss our findings in the context of existing literature and discuss the hypothesized origin of several of our observations with support from modeling efforts described elsewhere. • Projectiles penetrate deeper into wet sand than they do in dry sand. • Dry sand features more breakage and flow around projectiles than wet sand. • Impact chamber pressure significantly affects intermediate and final depths of penetration. • Two flash X-ray images can be used to reconstruct 3D flow fields during penetration. [ABSTRACT FROM AUTHOR]

In this work, we outline the development of a thermodynamically consistent microscopic model for a suspension of aggregating particles under arbitrary, inertia-less deformation. As a proof-of-concept, we show how the combination of a simplified population-balance-based description of the aggregating particle microstructure along with the use of the single-generator bracket description of nonequilibrium thermodynamics, which leads naturally to the formulation of the model equations. Notable elements of the model are a lognormal distribution for the aggregate size population, a population balance-based model of the aggregation and breakup processes and a conformation tensor-based viscoelastic description of the elastic network of the particle aggregates. The resulting example model is evaluated in steady and transient shear forces and elongational flows and shown to offer predictions that are consistent with observed rheological behavior of typical systems of aggregating particles. Additionally, an expression for the total entropy production is also provided that allows one to judge the thermodynamic consistency and to evaluate the importance of the various dissipative phenomena involved in given flow processes. [ABSTRACT FROM AUTHOR]

A systematic analysis of industrial iron ore sinter product and associated sinter returns was undertaken. The samples were characterised through identification of the major macro- and micro-structural types present in these materials. Examination of the breakage surfaces of the particles indicates a strong correlation between mechanical sinter strength and sinter microstructure. Preferential breakage was observed to occur in sinter materials having high porosity and those microstructures consisting of isolated hematite grains in a glass matrix. The bulk of the sinter product consisted of material with a microstructure of magnetite and silico-ferrite of calcium and aluminium (SFCA). The phases formed and the reaction sequences responsible for the formation of the principal microstructure types are explained by the non-equilibrium solidification of melts in the "Fe2O3"-Al2O3-CaO-SiO2 system. [ABSTRACT FROM AUTHOR]

The Selective Laser Melting (SLM) process has been progressively endorsed as an industrial manufacturing technique to produce high value-added components. However, one of the main obstacles to its wide application is the uncertainty regarding the successful completion of the manufacturing process. Mechanical stresses are generated and accumulated during the process, which may lead to the parts warping and cracking. Support structures may also detach from the part but it is not certain that these cracks conduct to the manufacturing failure. The process simulations currently available do not consider the cracking of the supports and the ongoing part's deflection. The aim of this study is to investigate cone supports fracture behaviour comparing the results from a numerical model and the manufacturing of an industrial part. A model using 1D-beam elements to mesh the supports has been developed to consider the damage of the supports, their breakage and the ongoing deflection. Some numerical convergence issues are identified and solutions are proposed. Specific experimental set-ups are developed to characterise the behaviour of the supports individually and as a group. Significant improvements are denoted while injecting the measured characteristics within the model. Some key parameters of the supports damage behaviour are identified. It is shown that the supports mechanical characteristics are significantly different from the parts due to their manufacturing conditions and environment. Also, limitations regarding the characterisation of the supports as well as strong numerical convergence issues brought by multiple supports cracking are discussed. [ABSTRACT FROM AUTHOR]

In the practice of archaeological field survey there is a manifest importance for densities, that is, an abundance of artifacts, often relying on simple counts of objects. However, a well‐known issue is variable breakage of pottery that can cause biases in quantitative analysis. Although such issues are generally acknowledged, a direct assessment of breakage and the resulting biases is lacking in research. This paper explores the pros and cons of quantification methods of surface collections in terms of counts or weights, and demonstrates the importance of analysing weight and breakage as part of an integrative approach. [ABSTRACT FROM AUTHOR]

Lead, copper, and cadmium ions were simultaneously extracted from a diluted acidic aqueous solution using Bis-2-ethylhexyl phosphoric acid (D2EHPA) as a carrier, Sorbitan monooleate (Span 80) as a surfactant, Kerosene as a diluent, and H2SO4 as a reagent. The effect of the pH of the external phase, surfactant, and carrier concentrations, speed of the homogenizer, and the volume ratio (v/v %) of the external/membrane phases on the system performance were investigated. High extraction efficiencies of Pb2+, Cu2+, and Cd2+ ions were obtained; 100%, 100%, and 98%, respectively. A minimum breakage of 1.8% was also obtained at the best operating conditions. A modeling study of the system has shown no significant interaction effects of the three solutes (Pb2+, Cu2+, and Cd2+) on each other. Therefore, the three solutes permeate from the feed phase to the stripping phase due to their chemical potential. The competitive transport of the three ions at low initial concentrations has been found to be comparable. At low concentrations, the low diffusion rates of the three ions were compensated by the increase of their distribution coefficients. This has been reflected on the enhancement of the transport rates of the three solutes through the membrane to be comparable. [ABSTRACT FROM AUTHOR]

In order to improve grinding efficiency and weaken over-grinding in the whole grinding process, the new process of "ultra-crushing in HPGR – classified separation" was proposed with an Anshan style hematite ore. The new process was discussed from the aspects of particle size distribution, liberation characteristics, and separation properties. Compared with the conventional impact crusher, there was no significant difference in coarse particles in HPGR. The "Particle Bed Breakage" characteristics of HPGR products are mainly concentrated in the fine particles (−0.18 mm), which is characterized by higher fines content (a yield of 38.43%), higher specific surface area and higher quartz liberation, etc. It's worth mentioning that, fine-disseminated iron minerals are detached from the quartz mineral under large compressive-stress in HPGR, which is more conductive to the downstream separation. Magnetic separation tests showed the HPGR (−0.18 mm) tailings have the lowest grade of 7.29%, approximately one percentage point less than coarse grinding products. Based on the above analysis, the new process with a 0.18 mm prescreen size for an Anshan style hematite ore is feasible. [ABSTRACT FROM AUTHOR]

Why fractal distribution is so frequent? It is true that fractal dimension is always less than 3? Why fractal dimension of 2.5 to 2.9 seems to be steady-state or stable? Why the fractal distributions are the limit distributions of the degradation path? Is there an ultimate distribution? It is shown that the finite fractal grain size distributions occurring in the nature are identical to the optimal grading curves of the grading entropy theory and, the fractal dimension n varies between --¥ and ¥. It is shown that the fractal dimensions 2.2--2.9 may be situated in the transitional stability zone, verifying the internal stability criterion of the grading entropy theory. Micro computed tomography (μCT) images and DEM (distinct element method) studies are presented to show the link between stable microstructure and internal stability. On the other hand, it is shown that the optimal grading curves are mean position grading curves that can be used to represent all possible grading curves. [ABSTRACT FROM AUTHOR]

A population balance framework for fluidization of A l 2 O 3 nano-agglomerates in a ProCell-type spouted bed considering agglomeration and breakage phenomena is developed. An equipartition of kinetic energy (EKE kernel) is used to model the agglomeration phenomena. For breakage, two different fragment distribution functions are considered, the Dirac delta function and a function with confined uniform binary breakage. The fractal dimension property is incorporated in both the agglomeration and breakage models. The model parameters are extracted from batch fluidization experiments conducted by varying the air pressure of the top nozzle. The developed model shows a good agreement with experimental observation in regard of the temporal change in the area and volume-weighted average size of nano-agglomerates and of their final size distribution. The developed population balance model is simulated to study the influence of model parameters on the evolution of average size and coefficient of variation of the nano-agglomerates. [Display omitted] • PBE model is developed for fluidization of Al 2 O 3 nano-agglomerates in a spouted bed. • The developed model considers agglomeration and breakage of nano-agglomerates. • EKE kernel is used to model the agglomeration phenomena. • Two different daughter distribution functions are considered for breakage. • The developed model predicts the temporal change in average size with good accuracy. [ABSTRACT FROM AUTHOR]

Introducing a novel ballast material based on reinforcing steel slag aggregates with strips of scrap tire can be beneficial due to decreasing the crushing and increasing the damping of the ballast materials. Moreover, recycling the two waste materials included in this novel ballast has a positive impact on environmental preservation. In this regard, the Waste Tire Reinforcement (WTR) consists of strips of truck scrap tire (385/80/R22.5) with a width of 70 mm utilized in grid shape (with various dimension grids of 21 ×7, 11.5 ×7, and 7 ×7 cm) as a reinforcement element. To evaluate the performance of suggested reinforcement with Steel Slag Ballast (SSB), a series of ballast box tests were performed up to 100,000 loading and unloading cycles with a magnitude and frequency of 30 kN and 3 Hz at three different levels of 5, 10, and 15 cm for WTR placement in ballast. The experimental results revealed that the WTR reinforcement with grids of 11.5 × 7 cm and a placement height of 5 cm (WTR11.5–5) has the best performance compared to other configurations. Compared to SSB without reinforcement, WTR11.5–5 may reduce breakage by more than 90% and increase the damaging ratio by 160%. • Investigation the cyclic behavior of Steel Slag Ballast(SSB) and Grids of Truck Scrap Tire using ballast box test. • Waste Tire Reinforcement (WTR) consists of strips of truck scrap tire. • Recycling of the two included waste materials in this novel ballast has a positive impact on environment preservation. • Compared to SSB without reinforcement, WTR may reduce breakage by more than 90% and increase the damaging ratio by 160%. [ABSTRACT FROM AUTHOR]

Objective: The Lisfranc complex is an osseo-ligamentous structure consisting of multiple tarsal and metatarsal bones, joints, and ligaments. The transarticular screw method is the most commonly preferred fixation technique in patients with Lisfranc injury. However, screw breakage complications can be seen with a considerable frequency. Although there are studies in the literature that associate the risk of screw breakage with the diameter or structure of the screw used, there is still no consensus. The aim of this study is to predict the risk of screw breakage by examining many parameters. Methods: We retrospectively evaluated 61 patients with lisfranc injuries who underwent transarticular fixation with screws of different diameters and properties. We found screw breakage complications in 9 (14.7%) of the patients. Some demographic and radiological parameters were examined to predict screw breakage in these patients. Age, gender, weight, diameter and structure of the screw used, presence of accompanying cuneiform, cuboid or metatarsal base fracture, how many tarsometatarsal joints were involved and whether anatomical reduction was achieved. In addition, the development of post-traumatic arthrosis during the 2-year follow-up, and the American Orthopedic Foot and Ankle Association (AOFAS) -Middle Foot Score and Visual Analogue Scale (VAS) scores were also compared in clinical evaluations. Results: We could not find any radiological or demographic parameter that could predict the screw breakage complication in the results. We found only that post-traumatic arthritis was significantly more common in patients with screw breakages. We also found that there was no significant difference in AOFAS-midfoot and VAS scores in patients with or without screw breakage complications. Conclusion: In the transarticular screw fixation of Lisfranc injury; screw's diameter, cannulated or solid structure, the presence of accompanying tarsal or metatarsal injuries and the reduction quality of the injured anatomic structures do not pose any risk factors for the screw breakage complication. [ABSTRACT FROM AUTHOR]

The mechanism that leads to fine particle production during pulse combustion drying is still unclear. Although droplet breakup could happen, it cannot result in particles below micron-size. Here production of fine particles during pulse combustion drying is investigated experimentally and numerically. Experiments with three different materials, namely SiO2, TiO2, and maltodextrin, have been conducted to see how the material types and process conditions influence the physical properties of the products. The results show that fine particles can be obtained with and without pulsation, and no significant differences are observed with the variation of pulsation frequency. The volume fraction of the fine particles is, however, very low. Based on these results, a model of particle production through repetitive crust breakage and drying cycles is proposed. The obtained results are in agreement with the experimental data, and the proposed mechanism could explain the production of fine particles with and without gas pulsation. [Display omitted] • Production of maltodextrin, SiO 2 , and TiO 2 particles using pulse combustion drying. • Fine particles could be produced irrespective of gas pulsation. • Repetitive crust breakage is proposed as mechanism for fine particle production. • Model of crust breakage during 2nd drying stage. [ABSTRACT FROM AUTHOR]

Rice is consumed as intact grain, and any broken grains are discounted from the main marketable product. Breakage of rice mainly arises from cracks formed in the endosperm before or after milling. The cracks are formed by stress gradients that arise due to moisture absorption or desorption by grains. As a result of such stress, cracks mostly develop in a direction perpendicular to the length of the grain, making it less physically resistant to the stresses of milling, handling, and soaking processes. Until now, research into rice cracking has mainly focused on minimizing breakage during milling, and no significant knowledge is available on the impact and mechanisms of post-milling cracking and/or breakage and its effect on the downstream quality of rice. This article aims to review the existing information on the causes of rice cracking before and after milling. [ABSTRACT FROM AUTHOR]

[Display omitted] • A bi-directional coupling of DEM and PBM examines the failure of tablets under abrasive conditions. • A methodology to understand the process-property relationships and reduce testing. • Multi-stage calibration procedure for empirical breakage kernels. • Mass loss and fragment PSD computed based on the collision energy distribution. • Models validated against friability test. A bi-directional coupling between the Discrete Element Method (DEM) and Population Balance Modelling (PBM) is suggested to model the failure of pharmaceutical tablets under abrasive conditions such as bulk flow of impact. DEM provides the description of kinetics and permits the extraction of collision energy distributions. Representation of the primary shape of the tablets is achieved by using the multi-sphere approach, a rigid assembly of systematically connected spheres to resemble non-spherical shape. Based on the collision energy distribution and the abrasion characteristics of the tablets by solving the PBM equations, the mass loss of tablets according to their mechanical resistance, as well as the fragment size distribution progeny can be computed. For the description of the abrasive failure characteristics, a multi-stage calibration procedure for the empirical breakage kernels of Vogel and Peukert as well as of Ghadiri and Zhang is also applied. The novelty of the presented approach is the bi-directional coupling: tablet and fragment distribution masses are dynamically updated for subsequent time steps in DEM by the particle replacement method according to the stress history of the system. The outcome of this methodology helps to get a deeper understanding of the process-property relationships, to evaluate the effect of any process or geometry modifications in processing operations, such as drum coating, and to reduce the requirements of experimental investigations. [ABSTRACT FROM AUTHOR]

Background: Orthodontic retention aims to maintain optimal teeth positions after active treatment. The stability is affected by numerous factors, including patients' individual features, thus retention should be adjusted in the most optimal way. Bonding a retainer makes retention less dependent on patient's compliance. Questions arise: What wire or fiber splint type provides the best treatment stability? What materials should be used to bond the wire or fiber splint? Should be the bonding procedure be direct or indirect? The aim of the study is to assess and synthesize available controlled trials investigating failures of fixed retainers. Methods: Literature searches of free text and MeSH terms were performed in Scopus, Web of Science, Embase and PubMed Central in order to find studies, referring to failures of fixed retention (12th February 2021). The keywords were: ("orthodontic retainers AND failure AND wire"). The framework of this systematic review according to PICO was: Population: orthodontic patients; Intervention: fixed orthodontic retainer bonding; Comparison: Different protocols of fixed orthodontic retention applied; Outcomes: failure rate, survival rate. Three different specific scales from the Cochrane Collaboration Handbook were used, according to each study type. Additionally, a meta-analysis was conducted to compare the effectiveness of retention using fiber reinforced composite and multistranded steel wire. Results: The search identified 177 potential articles: 114 from PubMed, 41 from Scopus, 20 from Web of Science and 2 from Embase. After excluding studies inconsistent with selection criteria, 21 studies were included and subjected to qualitative analysis. The main outcome investigated was failure rate. This systematic review has some potential limitations due to the heterogeneity of design between included studies. Conclusions: No retainer is proved to guarantee a perfect stability of dental alignment. The retainer should be bonded to all adherent teeth, preferably with additional use of bonding resin. No wire or fiber splint present superior characteristics concerning failure rate. Fiber reinforced composite retention is more sensitive to operator skills, and with imperfect bonding technique, failure rate is much higher. During the first 6 months after bonding retainer the patient should be under frequent control. The study protocol was registered in PROSPERO database with the number CRD42021233406. [ABSTRACT FROM AUTHOR]

[Display omitted] • Modelling particle breakage without mass loss in a parallelized DEM framework. • Acceleration of fragment growth by allowing fragment-fragment overlaps. • Good agreement between experiment and simulation. • Breakage model is suitable to model comminution in compressed packed beds. The particle based Discrete Element Method (DEM) can be applied to examine comminution processes. In this study, a DEM framework has been extended to model particle breakage without mass loss. After a breakage event occurs, spherical particles, as often considered in the DEM, are replaced by size reduced spherical fragments. During the following time steps, the fragments grow to their desired sizes, so that the mass loss can be counterbalanced. Previously defined overlaps with adjacent unbroken and broken particles (fragments) as well as walls are allowed. The breakage model has been realized in a parallelized DEM framework because comminution processes are often attributed to large numbers of particles and by parallelization the computational time can be reduced efficiently. An oedometer (one-dimensional compression in axial direction of a confined particle bed) has been modelled to investigate the parallelization efficiency and the influence of the permitted overlaps during the growth process on the growth duration. A simplified roller mill has been considered to examine the applicability of the breakage procedure considering parallelization. The results show that parallelization reduces computational time considerably. The breakage procedure is suitable to model comminution processes involving even densely packed particle systems and is superior to existing approaches. [ABSTRACT FROM AUTHOR]

[Display omitted] • A model has been proposed for the prediction of breakage in a high-shear mixer. • The capillary number and the pore saturation appear to be the key parameters. • Data fitted to the model is well-predicted. • The model does currently not extend to different powder-binder systems. Granule breakage is an important rate process in wet granulation that promotes product uniformity and controls product size and strength. In this work, a model to predict granule breakage is proposed and experimentally validated. The model assumes exponential of the surviving granules, dependent on a probability of breakage; a function of powder and binder properties, as well as operating parameters. Validation experiments were performed with a breakage-only granulator, filled with cohesive, non-granulating sand. Premade pellets made from lactose monohydrate and silicone oils were granulated at several impeller speeds, and the number of survivors was observed over time. The results revealed that the number of granules did indeed decay exponentially. It was found that the overall probability of breakage was inversely proportional to the capillary number. Moreover, the pore saturation played an important role in determining the probability of breakage, with higher pore saturations reducing breakage overall. A comparison with experimental data from literature revealed that the developed models agrees qualitatively with the experimental data, but is unable to fully capture the effect of powder properties and powder-binder interaction. [ABSTRACT FROM AUTHOR]

Mitigating gibbsite particle cracking and breakage during industrial alumina production can increase the quality of smelter grade alumina product by reducing the ultrafine particle content. Therefore, it is essential to investigate the particle cracking during static calcination and the breakage of calcined gibbsite particles under external force. In this work, we investigated the impact of the calcination ramping rate and the crystallite size on gibbsite particle cracking during static calcination. A slow ramping rate and a large pristine crystallite size tend to increase particle cracking. Apart from the study of particle cracking behaviour, we also investigated the breakage of calcined gibbsite particle under external force. Cracks on the particle surface can initiate breakage within the crystallite and along the grain boundary under external force. The breakage within crystallite occurs as the cleavage of the crystallite, while the breakage along the grain boundary leads to the shedding of a whole crystallite. We further explored the factors influencing the strength of calcined gibbsite particles. With increasing calcination temperature, the strength of particle increases when gibbsite converts to boehmite, and then decreases when boehmite converts into amorphous alumina. Particles containing smaller crystallites and calcined with fast ramping rates exhibit higher resistance to breakage. [ABSTRACT FROM AUTHOR]

Identification of screen breakage in a hammer millis relying mainly on the manual feed sampling currently in Chinese feed industry. There are four disadvantages in the manual selection for the feed via artificial senses:a )Human errors and failings easily occurred in the mechanical detection of online system; b)Low efficiency is difficult to meet the requirements of automatic production in modern agriculture; c)High misdetection rate can result in the unqualified granularity of product; d)The procedure is costly, time consuming and labor intensive, sometimes involving hazardous chemicals. In this study, an online automatic identification system mounted on a novel sampling mechanism was established for the rapid and accurate detection of screen breakage in a hammer mill using imaging technology and machine vision. Three key parts were designed in the device, including sampling mechanism, screening mechanism, and image acquisition. Specifically, the sampling mechanism mainly consisted of a chute feeder, and automatic sampling components. The screening mechanism was composed of a vibrating feeding device, screen components, and feeder base. The platform of image acquisition included camera bellows, cloud platform, and complex optical assembly, such as camera, lens, as well as an annular LED light source. The sampling mechanism was selected to automatically select feed samples in real time. The screening mechanism was applied to screen and separate the obtained samples, thereby transfer the samples to the next mechanism. The platform of image acquisition was then applied to collect the image of particles in the samples. A Siemens S7-200 PLC programmable controller was applied to realize automatic control in the whole system, including sampling, sample screening, vibrating, and image collecting. Python language was used for the image processing and programming, graying, denoising, and binarization that contained in image preprocessing, where the contour of large particles and the minimum circumscribed rectangle were determined during the program. The equivalent diameter of projected circle and the minimum area of circumscribed rectangular for the screened large particles were taken as the characteristic parameters, and the threshold. K-nearest neighbor and radial basis function support vector machine were utilized to establish the identification model of screen breakage. The accuracy rates of threshold model were 98% and 93% for the diameters of 1.0 and 2.0 mm in the screen identification. The recognition model established by the threshold was not reliable to deal with the experimental data, due to the different distribution of dataset. The accuracy rates of KNN(K-Nearest Neighbor, KNN) model were 94% and 96% for the diameters of 1.0 and 2.0 mm in the screen identification, when k=3, and the input parameters of the nearest neighbor KNN model were set as the average diameter of projected circle and the average minimum of circumscribed rectangular area. When the input parameters of the radial basis kernel function support vector machine (RBFSVM) model were set as the average diameter of projected circle and the average minimum of circumscribed rectangular area, and the optimal penalty coefficient and gamma parameters (C, g) were (2-5, 2-7) and (2, 2-1), respectively, the recognition accuracies of RBFSVM model were 89% and 91% for the diameters of 1.0 and 2.0 mm in the screen identification. As such, the KNN recognition model was determined as the recognition of system, in case there was no significant difference between the running speed of KNN and RBFSVM models. The newly developed device can provide a promising technical support to the online automatic identification of screen breakage in a hammer mill. [ABSTRACT FROM AUTHOR]

The kinetic energy loss in particle-wall impact is distributed between different mechanisms. These mechanisms were modeled using only material mechanical properties, impact conditions and particle area. With this model, the particle breakage probability (BP) was plotted in terms of the available energy to damage the particle. It was found that breakage probability is scaled well with the available energy for softer targets. Thus, a generic BP function can be derived for different types of targets. Additionally, particle fracture energy is modeled in terms of surface energy and the new exposed area. This area was evaluated using Monte-Carlo simulations. The simulation results suggest that SiC fracture energy is larger compare to quartz because of smaller surface energy. For potash, the compression energy obtained in quasi-static compression tests is found to be larger than the fracture energy in impact. But if plastic deformation and fracture is considered, it exceeds the compression energy. Unlabelled Image • Full energetic scheme to determine the energy absorption by different mechanisms is given. • Breakage probability is scaled well with the available energy, i.e. subtracting the energy absorbed by the wall. • Particle fracture energy is modeled in terms of the surface energy and new area that was exposed due to fracture. • Compression energy obtained in quasi-static compression tests is 50–500 times larger than the fracture energy in impact. [ABSTRACT FROM AUTHOR]

Detailed surgical management, magnetic resonance imaging (MRI), and computer tomography (CT) images of a broken annular closure device (ACD) have not been reported yet. In this case, a 28-year-old male presented with a new onset of radiculopathy three years after lumbar discectomy and placement of an ACD. The CT-myelography and MRI revealed a recurrent disc herniation (RDH) and dislocation of a broken ACD. ACD removal was performed and confirmed breakage due to RDH with scarring around the RDH and displaced ACD. Implant-associated complications and management should be reported in detail in order to enhance knowledge on device-related complications. [ABSTRACT FROM AUTHOR]

• A novel device has been developed for assessing granule attrition. • Granules are subjected to continuous shearing and repeated impacts. • Design and operation of the tester are described and settings specified. • Realistic manufacturing plant mechanical stresses are simulated. • Results reveal a coupled effect of impact and shearing for some granules. A novel device has been developed for continuous shearing and repeated impact of granules in order to simulate granule attrition and dust formation under realistic plant conditions of mechanical stresses, shear strains and strain rates. The device subjects the granules to multiple impacts at a range of velocities prevailing in typical process plants, and to shear deformations using two rollers with an adjustable gap to simulate the level of shear stresses and strains experienced during bulk motion, e.g. discharge from silos onto conveyor belts, etc. In this paper, the device operation and tests carried out to determine the settings required for attaining a desired impact velocity and shear strain rate are described. Subsequently, the extent of breakage of the granules is determined for the specified settings and the results are compared with data obtained by more established methods, e.g. annular shear cell and single particle impact tests. [ABSTRACT FROM AUTHOR]

[Display omitted] • Performance of FPT and FVS for resolving multi-dimensional breakage was assessed. • Numerical solutions were validated against analytical moments and number density. • FVS is simple but requires different formulations to preserve different properties. • FPT is more complex but can preserve up to four properties with one formulation. When modeling particle breakage, the use of a single dimension to characterize particulate systems becomes intractable when multiple dimensions (e.g., size and shape) are important. Amongst many potential numerical techniques, the Fixed Pivot Technique (FPT) and Finite Volume Schemes (FVS) are popular choices to resolve multi-dimensional breakage population balance equations (PBEs). However, whether there exists a general multi-purpose technique between the two remains unclear. Across all test cases with identical size domain and mesh, while both techniques demonstrate comparable accuracy in resolving the moments and number densities (with maximum difference in average relative errors of ∼O(100) and ∼O(102), respectively), and exhibit similar computational efficiency (time taken by FPT relative to FVS is of ∼O(100)), the choice of numerical technique is contingent upon the properties where accurate prediction is critical. To this end, FVS is the preferred choice when precise estimation of up to two properties is required owing to its simplicity, albeit requiring distinct schemes for different properties. Conversely, when more than two properties are crucial, the FPT is more suited as it preserves up to four properties in the internal 2D space. Overall, this work offers rational guidance for efficient and accurate modeling of multi-dimensional breakages. [ABSTRACT FROM AUTHOR]

• A unified Monte Carlo approach for simultaneous coagulation and breakage problems. • Global reconstruction of stochastic weighted particles. • High-precision predictions of PSDs and moments with good computational efficiency. • Low statistical noise for long-time simulations. This paper proposes a unified Monte Carlo approach to model simultaneous particle coagulation and breakage processes. Based on the reconstruction of stochastic weighted particles, the present approach treats coagulation and breakage in a unified sense and resamples the weighted particle population globally. The prediction results are validated through several benchmark coagulation-breakage cases with known analytical solutions, and the performances are compared with those of conventional combination approaches. It is confirmed that, in terms of resolving particle size distribution and moments, the proposed reconstruction approach generally yields higher computational accuracy and efficiency, with especially reduced statistical noise for long-time simulations. The simple implementation, the unified treatment for different dynamic processes, and the well-balanced accuracy and efficiency make this new approach a promising candidate for solving general population balance problems of particles. [ABSTRACT FROM AUTHOR]

The planetary mill is one of the most commonly used mills for ultrafine grinding in the laboratory, given its ability to reach higher intensity of the collisions as the result of increase in rotational frequency and ball acceleration without the undesired centrifugation of the grinding charge. Several attempts have been made in the literature to develop a predictive model of this mill, with limited success. The work applies the mechanistic UFRJ mill modeling approach to predict the size distribution in a laboratory planetary mill, on the basis of single-particle slow compression data obtained using a micro compression tester, besides simulations using the discrete element method. At first, careful verification of the Hertz-Mindlin contact parameters was conducted using a video recording system that moves along with the jar during milling. Grinding tests were conducted with hematite for the mill operating at frequencies that varied from 150 to 300 rpm, resulting in generally very good agreement between model and experiments. However, agreement between the two was found to reduce for the highest rotational frequency studied. This was attributed to the reduction in grinding efficiency in the experiments that was not observed in the simulations, which resulted in predicted values overestimating fineness of the product. Finally, simulations were compared to experiments for quartz, silicon carbide and blast furnace slag under identical conditions and it was shown that the model provided very good predictions, with the exception of quartz. Overview of application of UFRJ Mechanistic Mill Model to predict planetary milling. [Display omitted] • Media motion in a planetary mill recorded using special video recording system. • Fine particle breakage data used to model key breakage parameters. • Good ability of mechanistic model in predicting planetary milling of hematite. • Predictions were optimal at lower mill frequencies. • Very good predictions for other materials at 200 rpm, with minimal model fit. [ABSTRACT FROM AUTHOR]

• Drivers for growth and challenges for the mineral processing industry are reviewed. • DEM models including breakage are capable of simulating industrial scale crushers. • Compression and impact crushers can be investigated in detail using these models. • Breakage and flow are analysed in twin roll and cone crushers. • Crushing behaviour in a VSI involves multiple mechanisms of impact breakage. Particle scale modelling of comminution processes can provide significant insight into the flow of particles, their breakage, the effect of slurry, wear and energy utilisation within these machines. The ability to use such models to assist in faster and lower cost design of new comminution devices and in the improvement of existing ones will be critical to the ability of industry to respond to the substantive challenges facing mineral processing in the next decade. These challenges are reviewed and drivers for change are discussed. Understanding individual unit process performance needs to be in the context of the flowsheets in which they are used so this is also reviewed. Advances in particle based comminution modelling are presented with this work divided into two parts. This first part focuses on recent advances in particle based modelling of crushing. Three crusher types are used to demonstrate these capabilities: 1. Twin roll crusher 2. Cone crusher 3. Vertical Shaft Impactor (VSI) These show the nature and level of fidelity that is now possible to include in particle scale crusher models including breakage of non-spherical particles and prediction of the product size distribution and throughput. [ABSTRACT FROM AUTHOR]

Spring steel is a name given to a wide range of steels used in the manufacture of springs, prominently in automotive and industrial suspension applications. High carbon of HC82BCr grade steel is drawn in the range of 4.0–3.0 mm as per customer's requirement for production of spring mainly in automobile components. This spring steel grade is produced from continuous cast billet of size 150 mm × 150 mm and then hot rolled into the size of 5.5 mm diameter wire rod. Quality aspects of these spring are significant as any inherent abnormality in the material could lead to unwanted productivity losses or quality claims or sometimes serious safety issues. In this present study, spring samples broken during coiling stage were collected from plants for understanding their quality aspect and potential causes of breakage during production. Detailed microstructural investigation revealed that the root cause of breakage of the spring is related to the segregation of phosphorous and chromium in the billet which leads to the formation of martensite (brittle and less ductile) in wire rod during rolling process. This volume change due to formation of martensite increases the stress level at the interface of pearlite and martensite. During wire drawing, this increased stress level causes formation of internal crack in subsequent passes causing breakage during spring formation. [ABSTRACT FROM AUTHOR]

The cube is considered the best shape for high-quality ballast aggregates. However, the presence of flaky and elongated aggregates (misshapen particles) caused during ballast production is unavoidable. In this regard, the consequence of using this shape of ballast is not well investigated. In this study, first a series of large-scale direct shear tests were carried out under various vertical stresses of 50, 100, and 200 kPa to evaluate the breakage and level of fines in ballast samples categorized by the flakiness and elongation index. Second, the discrete element method (DEM) was employed to simulate tests concerning the breakage of particles. The results showed that there was a 14.7% and 5.2% decrease in strength and friction angle of aggregates with 20% increase in the percentage of flaky aggregates. An aggregate limit of 25% by weight for misshapen particles is recommended to meet the minimum shear stress level of the flaky ballast sample in the Chinese standard. Despite higher shear strength at low vertical stresses compared with cubic aggregates, flaky and elongated aggregates result in higher deterioration and shorter service life in the long term. [ABSTRACT FROM AUTHOR]

• Successful extraction (more than 95%) of tetracycline hydrochloride by LSM technique in the presence of TBP as carrier. • High membrane stability with minimum breakage of 1.23% and sauter mean diameter (d 32) of 4.82 μm were obtained. • Effects of various experimental parameters on LSM performance were investigated. • Successful recyclability of the membrane phase to extract tetracycline up to three times with the same extraction efficiency. In this article, the removal of tetracycline (TC) from aqueous solutions was investigated by liquid surfactant membrane technique using n -heptane as a diluent, span80 as a surfactant, tri-butyl-phosphate as carrier, and HCl acid as the internal phase. The effect of various operating parameters on the emulsion stability by means of breakage and sauter mean diameter and the extraction efficiency were studied such as homogenizer speed, emulsification time, internal to membrane volume ratio, surfactant concentration, internal phase concentration, carrier concentration, external phase pH, mixing speed and external to emulsion volume ratio. Maximum extraction of TC was found to be more than 95% after 15 min contact time under the optimum experimental condition that gives a lowest membrane breakage of 1.23% and best sauter mean diameter (d 32) of 4.82 μm. While 93% of the extracted TC can be stripped by the internal phase. The reusing of membrane phase was also investigated throughout this work, and the results indicated that the extraction efficiency slowly decreased and the stability enhanced with the reusing process up to three times. [ABSTRACT FROM AUTHOR]

A new framework for DEM modelling of deformable and breakable particles is presented. In our approach, real-life particles are modelled as agglomerates (or clusters) of many DEM particles forming spherical clumps and interacting via a linear elasto-plastic force. Such interaction provides a finite equilibrium overlap, resulting in mechanically stable clusters after agglomeration. Since inter-particles bonds are elastic, clusters can be used to model particles or structures that can deform elastically, plastically or break. Different clusters can bond as well, providing the basis for modelling complex particle agglomeration. The framework is described, and key structural properties of clusters are defined and analytically related to DEM components packing and their material properties. These relations are numerically validated showing a very good agreement, enabling clusters to be designed with a precise structure. Applications of this model range from particle deformation and breakage to porous structures, from soil mechanics to die compaction and tableting. Unlabelled Image • New framework for creating DEM particle clusters. • Clusters exhibit elastic recovery, plastic deformation and breakage. • Clusters structural parameters related analytically to DEM particles properties. • Numerical validation of clusters structure theory. • First step towards a more realistic modelling of particle compaction. [ABSTRACT FROM AUTHOR]