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This study presents a comprehensive discrete element method (DEM) simulation approach for the stretching of a filter fiber with a separated polydisperse particle structure on top. For a realistic interaction between the fiber surface and the particles, the original surface of the polymer fiber was projected onto the surface of the fiber cylinder using surface imaging technologies (atomic force microscopy (AFM) and white-light interferometry). In addition, the adhesive forces between particle–fiber and particle–particle contacts were calibrated in the DEM domain using values from self-conducted AFM measurements. Fiber stretching was implemented by the linear motion of small periodic fiber elements. Discretization problems were resolved through studying the stretching of a fiber segment at the size of 8 mm. A critical fiber element length was discovered to be ≈100 μm for minimizing discretization dependencies during the cracking of the particle structure. The number and density of particle–particle contacts within the particle loading on the fiber were obtained at two different elongation rates. Effects such as densification of the particulate structure and increased detachment due to additional air flow were demonstrated.

This paper investigates the response of Ottawa sand to cyclic loading using virtual oedometer tests and the level-set discrete element method. We study both the macroscopic and the micromechanical behavior, shedding light on the grain-scale processes behind the cyclic response observed in crushable sand, namely stress relaxation under strain control and ratcheting under stress control. Tests without particle breakage first show that asymmetrical frictional sliding during loading-unloading induces these cyclic-loading effects. Then, tests considering particle breakage reveal more pronounced stress relaxation and ratcheting, which decrease in rate over cycles, accompanied by increased frictional sliding and reduced particle contact forces. It is found that the broken fragments unload the most and promote an enhanced cushioning effect. These micromechanical processes contribute to a decrease in breakage potential as the cycles progress, implying that cyclically loaded materials may become more resistant to breakage when compared to the same material loaded monotonically at the same strain level. These new insights highlight the main contributions of the present work, factoring in real particle shapes from 3D X-ray tomography and notably contributing to the existing literature on the topic, where most studies rely on idealized particle shapes and rarely consider crushable grains. [ABSTRACT FROM AUTHOR]

The most common railway ballast is produced by quarrying, and its mechanical characteristics are crucial for both stability and drainage for safer and faster rail operations. Ballasted tracks have certain drawbacks, primarily because ballast starts to degrade over time. In this regard, reducing the rate of ballast degradation is vital to enhance track longevity and minimise maintenance costs. This study demonstrates how segments of huge waste rubber tyres (e.g., 3 m in diameter) from the mining industry can be used to improve the stability of tracks, while contributing to reduced ballast deformation and degradation. By placing arched segments cut from these tyres along the track shoulders beyond the edge of sleepers (i.e., the plan view gives a schematic impression of a caterpillar), the in-situ lateral confining pressure can be increased from 20–25 (standard track) to 40–50 kPa. This novel idea of confined-caterpillar track (CCT) was tested at a prototype physical model (1:1 scale) at the National Facility for the Heavy-haul Railroad Testing, and the experimental outcomes were compared with the performance of a conventional track. Apart from constributing to at least 25% saving of quarried aggregates, the test results prove that the CCT concept can curtail the lateral displacement and settlement of the ballast layer, while reducing particle breakage and affecting significant stress reduction in the underlying substructure layers. [ABSTRACT FROM AUTHOR]

In order to solve low recognition of corn kernel breakage degree and corn kernel mildew degree during corn kernel harvesting, this paper proposes a real-time detection method for corn kernel breakage and mildew based on improved YOlOv5s, which is referred to as the CST-YOLOv5s model algorithm in this paper. The method continuously obtains images through the discrete uniform sampling device of corn kernels and generates whole corn kernels, breakage corn kernels, and mildew corn kernel dataset samples. We aimed at the problems of high similarity of some corn kernel features in the acquired images and the low precision of corn kernel breakage and mildew recognition. Firstly, the CBAM attention mechanism is added to the backbone network of YOLOv5s to finely allocate and process the feature information, highlighting the features of corn breakage and mildew. Secondly, the pyramid pooling structure SPPCPSC, which integrates cross-stage local networks, is adopted to replace the SPPF in YOLOv5s. SPP and CPSC technologies are used to extract and fuse features of different scales, improving the precision of object detection. Finally, the original prediction head is converted into a transformer prediction head to explore the prediction potential with a multi-head attention mechanism. The experimental results show that the CST-YOLOv5s model has a significant improvement in the detection of corn kernel breakage and mildew. Compared with the original YOLOv5s model, the average precision (AP) of corn kernel breakage and mildew recognition increased by 5.2% and 7.1%, respectively, and the mean average precision (mAP) of all kinds of corn kernel recognition is 96.1%, and the frame rate is 36.7 FPS. Compared with YOLOv4-tiny, YOLOv6n, YOLOv7, YOLOv8s, and YOLOv9-E detection model algorithms, the CST-YOLOv5s model has better overall performance in terms of detection accuracy and speed. This study can provide a reference for real-time detection of breakage and mildew kernels during the harvesting process of corn kernels. [ABSTRACT FROM AUTHOR]

Peripherally inserted central catheter (PICC) is a widely used technique in oncology chemotherapy, characterized by safety, reliability, and long dwell time. However, a catheter can break due to various causes. When an acute rupture occurs, it always lead to sever complications which may threaten patients’ safety and potentially result in medical disputes. In this study, we collected and analyzed 3 cases of PICC line breakage causing drug leakage in our hospital from 2018 to 2023. All these 3 cases were postoperative breast cancer patients accepting chemotherapy, with 2 cases involving external partial breakage and 1 case involving internal partial breakage. Due to timely and appropriate management, no acute rupture occurred. We propose some ideas such as selecting high-quality catheter materials and avoiding over extension or repeated bending are crucial in preventing PICC line breakage. In addition, we also recommend establishing a standardized and scientific management pattern of PICC to ensure the safety and effectiveness of its clinical application, including comprehensive assessment, “four-element” intervention, and continuous evaluation.

High-quality cottonseed is essential for successful cotton production. The integrity of cottonseed hulls plays a pivotal role in fostering the germination and growth of cotton plants. Consequently, it is crucial to eliminate broken cottonseeds before the cotton planting process. Regrettably, there is a lack of rapid and cost-effective methods for detecting broken cottonseed at this critical stage. To address this issue, this study developed a dual-camera system for acquiring front and back images of multiple cottonseeds. Based on this system, we designed the hardware, software, and control systems required for the online detection of cottonseed breakage. Moreover, to enhance the performance of cottonseed breakage detection, we improved the backbone and YOLO head of YOLOV8m by incorporating MobileOne-block and GhostConv, resulting in Light-YOLO. Light-YOLO achieved detection metrics of 93.8% precision, 97.2% recall, 98.9% mAP50, and 96.1% accuracy for detecting cottonseed breakage, with a compact model size of 41.3 MB. In comparison, YOLOV8m reported metrics of 93.7% precision, 95.0% recall, 99.0% mAP50, and 95.2% accuracy, with a larger model size of 49.6 MB. To further validate the performance of the online detection device and Light-YOLO, this study conducted an online validation experiment, which resulted in a detection accuracy of 86.7% for cottonseed breakage information. The results demonstrate that Light-YOLO exhibits superior detection performance and faster speed compared to YOLOV8m, confirming the feasibility of the online detection technology proposed in this study. This technology provides an effective method for sorting broken cottonseeds.

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.

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]

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]

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]

The rock-breaking force of the disk cutter is affected by many factors. The greater the rock-breaking force applied to the disk cutter, the higher the breakage efficiency and removal in the rock masses, thereby speeding up the excavation speed and improving construction efficiency. The elastic-plasticity of rock materials will greatly affect the disk cutter rock-breaking force, thereby affecting the efficiency and speed of the TBM excavation process. The commercial finite element software LS-DYNA was performed to simulate the rock breakage mechanism by disk cutter, and the influence of three rock behavior models of elastic-plastic, plastic, and elastic models on the rock-breaking force by disk cutter was studied. Finally, the elastic model with the least influencing parameters was selected to study the effects of rock elastic modulus and disk-cutting depth on rock-breaking force. [ABSTRACT FROM AUTHOR]

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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]

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]

In the current study, the effect of the nonionic surfactant (span 80) on the emulsification of a mixture of kerosene as a petroleum-based organic solvent and span80 as a green diluent in the ratio 1:1 was investigated. NaOH was used as the internal phase, and the stability of the emulsion was tested. The potential for extracting phenol from aqueous solutions without the use of a carrier agent has been explored using Pickering emulsion liquid membrane. Additionally, the impacts of experimental parameters include homogenizer speed, mixing speed, emulsification time, Fe3O4-Span 80 ratios, NaOH concentration, and internal to membrane volume ratio (I/O) on extraction effectiveness and emulsion stability. The findings demonstrated that after 9 minutes of contact time and a minimum breaking percent of 0.745% under ideal circumstances, more than 96% of phenol could be recovered. In addition thermodynamic analysis reveals that the extraction process was an endothermic and spontaneous in nature and the overall mass transfer coefficient was 1.115 m/s. Membrane materials and nanoparticles were recycled four time in the extraction of phenol with approximately the same efficiency and no significant breakage percent..

In order to solve low recognition of corn kernel breakage degree and corn kernel mildew degree during corn kernel harvesting, this paper proposes a real-time detection method for corn kernel breakage and mildew based on improved YOlOv5s, which is referred to as the CST-YOLOv5s model algorithm in this paper. The method continuously obtains images through the discrete uniform sampling device of corn kernels and generates whole corn kernels, breakage corn kernels, and mildew corn kernel dataset samples. We aimed at the problems of high similarity of some corn kernel features in the acquired images and the low precision of corn kernel breakage and mildew recognition. Firstly, the CBAM attention mechanism is added to the backbone network of YOLOv5s to finely allocate and process the feature information, highlighting the features of corn breakage and mildew. Secondly, the pyramid pooling structure SPPCPSC, which integrates cross-stage local networks, is adopted to replace the SPPF in YOLOv5s. SPP and CPSC technologies are used to extract and fuse features of different scales, improving the precision of object detection. Finally, the original prediction head is converted into a transformer prediction head to explore the prediction potential with a multi-head attention mechanism. The experimental results show that the CST-YOLOv5s model has a significant improvement in the detection of corn kernel breakage and mildew. Compared with the original YOLOv5s model, the average precision (AP) of corn kernel breakage and mildew recognition increased by 5.2% and 7.1%, respectively, and the mean average precision (mAP) of all kinds of corn kernel recognition is 96.1%, and the frame rate is 36.7 FPS. Compared with YOLOv4-tiny, YOLOv6n, YOLOv7, YOLOv8s, and YOLOv9-E detection model algorithms, the CST-YOLOv5s model has better overall performance in terms of detection accuracy and speed. This study can provide a reference for real-time detection of breakage and mildew kernels during the harvesting process of corn kernels.

Purpose is to select the optimal composition of the mixed low-density explosive (Es) applied in the form of blasthole charges which provide high efficiency of blasting operations while mining of thin ore deposits. The abovementioned becomes possible while studying features of the foamed polystyrene chemical decomposition and gasification; role of additional water components as well as catalyzator being sodium carboxymethyl cellulose; and analysis of explosive characteristics of the compositions. Methods. The research involved lab-based experiments to define application efficiency of the recommended low-density blasting agents through identification of the basic explosive characteristics of the model mixed Es. Findings. The optimal composition of the mixed low-density Es has been developed. It consists of ammonia nitrate, diesel fuel, granulated foamed polystyrene, water, and sodium carboxymethyl cellulose to be used to break thin ore bodies. Owing to it, the possibility has arisen to control over a wide range both detonation velocity and pressure of blasting fumes during the charge density increasing or decreasing. The main detonative characteristics of the proposed compositions of low-density Es have been determined helping perform explosive rock mass loading in terms of extremely low values of both energy and explosive characteristics. The developed composition of the mixed low-density Es makes it possible to control quantity of Es energy in a volume well unit by means of increase or decrease in the charge energy concentration depending upon the changes in the rock mass resistance; in such a way, efficient breakage of thin ore bodies is provided inclusive of less dilution indicators. Originality. For the first time, dependence of the relative efficiency of the mixed low-density Es upon the foamed polystyrene volume content has been identified as well as dependence of pressure of blasting fumes upon the charging density. Practical implications are the development of procedures for blasting operations while thin ore body mining. The procedures are based upon formulating of the optimal composition of low-density Es differing in its simplicity, safety, and efficiency; and helping reduce prime cost of the extracted mineral at the expense of the decreased degree of the ore dilution. An empiric formula to define specific consumption of the low-density Es has been proposed for Akbakay mine. [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]

Powder breakage during pneumatic conveying negatively affects the properties of dairy products and causes increased dusting, reduced wettability, and decreased product performance. In particular, particle breakage is a serious issue for fat-filled milk powder (FFMP) which, if it breaks, releases fat that causes odours and leads to sticky blocked pipes. In this work, a conveying rig (dilute phase, positive pressure) with 50 mm diameter food grade stainless steel pipes (1.5 m high and 5 m conveying distance with three 90° bends, two in the vertical plane and one in the horizontal plane) was built as the test system. The effects of operating conditions (conveying air velocity and solid loading rate) on the attrition of FFMP in a dilute phase conveying system were experimentally studied. Four quality characteristics were measured before and after conveying: bulk density, particle size distribution, wettability, and solubility, to access the influence of particle breakage. Conveying air speed shows a significant impact on powder breakage. As air speed increased, more breakage occurred, and the volume mean diameter D[4,3] decreased by around 50%, using the largest conveying air speed of 38 m/s. Bulk density increased accordingly whereas wettability decreased with an increase in air speed, resulting from the higher breakage rate. On other hand, improving the solid loading rate can further reduce the breakage level, but the positive effect is not as good as decreasing air speed.

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]

ABSTRACT. Increasing complexity of ore deposits requires operations to be continuously improving their cost competitiveness. Mathematical modelling and process simulation techniques are useful tools to understand the process, define bottlenecks and increase process efficiencies. This paper presents a crushing and grinding circuit of a chromite ore gravity separation plant’ simulation model results and actual plant operating data. Throughout the study, jaw crusher, ball and rod mill summary equipment characteristics, breakage and selection functions employed, comparison of particle size distribution curves of site process streams to model results are presented. Simulation work is completed by using METSIM® software. The paper also showcases ease of flow diagram and process data presentation by the utilisation of the adequate simulation approach.

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]

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]

Powder breakage during pneumatic conveying negatively affects the properties of dairy products and causes increased dusting, reduced wettability, and decreased product performance. In particular, particle breakage is a serious issue for fat-filled milk powder (FFMP) which, if it breaks, releases fat that causes odours and leads to sticky blocked pipes. In this work, a conveying rig (dilute phase, positive pressure) with 50 mm diameter food grade stainless steel pipes (1.5 m high and 5 m conveying distance with three 90° bends, two in the vertical plane and one in the horizontal plane) was built as the test system. The effects of operating conditions (conveying air velocity and solid loading rate) on the attrition of FFMP in a dilute phase conveying system were experimentally studied. Four quality characteristics were measured before and after conveying: bulk density, particle size distribution, wettability, and solubility, to access the influence of particle breakage. Conveying air speed shows a significant impact on powder breakage. As air speed increased, more breakage occurred, and the volume mean diameter D[4,3] decreased by around 50%, using the largest conveying air speed of 38 m/s. Bulk density increased accordingly whereas wettability decreased with an increase in air speed, resulting from the higher breakage rate. On other hand, improving the solid loading rate can further reduce the breakage level, but the positive effect is not as good as decreasing air speed. [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]

Fluid bed granulation is faced with a high level of complexity due to the simultaneous occurrence of agglomeration, breakage, and drying. These complexities should be thoroughly investigated through particle–particle, particle–droplet, and particle–fluid interactions to understand the process better. The present contribution focuses on the importance of drying and the associated challenges when modeling a granulation process. To do so, initially, we will present a summary of the numerical approaches, from micro-scale to macro-scale, used for the simulation of drying and agglomeration in fluid bed granulators. Depending on the modeled scale, each approach features several advantages and challenges. We classified the imposed challenges based on their contributions to the drying rate. Then, we critically scrutinized how these challenges have been addressed in the literature. Our review identifies some of the main challenges related to (i) the interaction of droplets with particles; (ii) the drying kinetics of granules and its dependence on agglomeration/breakage processes; as well as (iii) the determination of drying rates. Concerning the latter, specifically the surface area available for drying needs to be differentiated based on the state of the liquid in the granule: we propose to do this in the form of surface liquid, pore liquid, and the liquid bridging the primary particles. [ABSTRACT FROM AUTHOR]

The mechanical properties of calcareous sands are critical as potentially important material sources for marine geotechnical constructions. Brittleness and large deformations created in calcareous sands can affect the stability of marine structures and geosynthetic reinforcement is a promising new approach. In this study, a series of consolidated-drained (CD) tests were conducted to evaluate the mechanical properties and deformation of woven geotextile-reinforced calcareous sand. For this purpose, the effect of geotextile layers, relative density, type of woven geotextile, and confining pressure were investigated. The results show that the strength of the reinforced specimens increases markedly compared to the unreinforced calcareous sand and the deviatoric stress-strain curves change from slight softening to hardening and dilatancy. Also, by increasing the number of woven geotextile layers and applying a confining pressure, the shear deformation shifts toward strain-hardening behavior. Overall, woven geotextiles significantly improve the apparent cohesion strength of calcareous sand soil. The woven geotextile, relative density, and confining pressure all contribute to volumetric changes and dilatancy of reinforced specimens, but particle breakage is more affected by confining pressure.

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]

[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]

The aim of this theoretical investigation is to seek any similarities between the Austin model and the Kotake-Kanda (KK) model for the specific breakage rate function in the population balance model (PBM) used for tumbling ball milling and assess feasibility of the KK model for scale-up. For both models, the limiting behavior for small particle size-to-ball size ratio and the extremum behavior for a given ball size are described by "power-law." Motivated by this similarity, specific breakage rate data were generated using the Austin model parameters obtained from the labscale ball milling of coal and fitted by the KK model successfully. Then, using the Austin's scale-up methodology, the specific breakage rate was scaled-up numerically for various mill diameter scale-up ratios and ball sizes of 30-49 mm and coal particle sizes of 0.0106-30 mm. PBM simulations suggest that the KK model predicts identical evolution of the particle size distribution to that by the Austin model prior to scale-up. Upon scale-up, the differences are relatively small. Hence, modification of the exponents in the Austin's scale-up methodology is not warranted for scale-up with the KK model. Overall, this study has established the similarity of both models for simulation and scale-up. [ABSTRACT FROM AUTHOR]

Purpose is to improve analytical technique to calculate strength of cylindrical rock samples taking into consideration standard horizontal stresses. Methods. Mathematical modeling of cylindrical rock sample breakage under the truncated-wedge destruction was performed taking into consideration the standard horizontal stresses using four experimental characteristics (i.e. k being shear strength; fс and μ being contact and internal friction coefficients; and Е being elasticity modulus) as well as comparing the design strength with experimental data obtained in the process of uniaxial compression. Findings. The technique makes it possible to identify both maximum strength and residual strength of cylindrical rock samples using four indicators of properties which can be simply defined by experiment. Comparison of the analytical strength limits and experimental data, obtained in terms of uniaxial compression, supports the idea of high efficiency of the proposed technique. Originality. For the first time, analytical modeling of cylindrical rock sample breakage has been performed in terms of the truncated-wedge destruction taking into consideration the standard horizontal stresses as well as contact and internal friction parameters. Practical implications. The technique advantage is to apply promptly the calculation results in the context of industrial enterprises since their environment helps apply simple procedures to define indices of physiсomechanical characteristics of rocks for determination of stability of underground structures and reduction of energy consumption while disintegrating in open pit s and mining and processing complexes. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on single particle breakage behavior of crushable weathered sands by a number of single particle uniaxial compression tests to comprehensively investigate the characteristics of single particle breakage, the probability of survival of single particle, and the effects of particle size and weathering on single particle strengths. The behavior of single particle under uniaxial compression falls into the mixed five phases: damage by chipping, elastic deformation, fragmentation by partial fracture, breakage by splitting, and the residuals, demonstrating the complexity and variability of the tensile strengths of single particles. The behavior of single particle breakage was quantified herein by the initial fracture and failure strengths of single particle. The probability of survival decreased as the characteristic stresses increased. An increase in the particle size or weathering number of single particle resulted in a reduction in the probability of survival of single particle. For a given probability of survival, the difference in the initial fracture characteristic stress and failure characteristic stress decreased with increasing particle size but showed a complex change with increasing weathering number. The probability of survival showed greater variability for the normalized initial fracture characteristic stress than for the normalized failure characteristic stress, implying that the initial fracture stresses of single particles diverged more than the failure stresses of the particles. The average initial fracture and failure characteristic stresses, and the initial fracture and failure characteristic stresses corresponding to 1/e (37%) survival of single particles decreased while increasing particle size or weathering number, but the decrease showed a sharper rate for smaller single particles with a lower weathering number. The ln-ln coordinates showed a linear representation of the failure characteristic stress and particle size, verifying the applicability of Weibull theory to single particle breakage. However, weathering resulted in downward translation and slight rotation of the linear relation of the failure characteristic stress and particle size in the ln-ln coordinates. [ABSTRACT FROM AUTHOR]

A mathematical description of a blood flow in the circulatory system based on the general equations of filtration of a multi-component mixture regarding the formation of a porous clot caused by the absorption of the components on the vessel wall and its destruction under the action of hydrodynamic forces has been performed. The influence of the shape and the structure of a clot formed at the blood vessel wall on the main hydrodynamic characteristics determining the probability of a clot breakage from the wall has been analyzed. [ABSTRACT FROM AUTHOR]

The aim of this theoretical investigation is to seek any similarities between the Austin model and the Kotake–Kanda (KK) model for the specific breakage rate function in the population balance model (PBM) used for tumbling ball milling and assess feasibility of the KK model for scale-up. For both models, the limiting behavior for small particle size-to-ball size ratio and the extremum behavior for a given ball size are described by “power-law.” Motivated by this similarity, specific breakage rate data were generated using the Austin model parameters obtained from the lab-scale ball milling of coal and fitted by the KK model successfully. Then, using the Austin’s scale-up methodology, the specific breakage rate was scaled-up numerically for various mill diameter scale-up ratios and ball sizes of 30–49 mm and coal particle sizes of 0.0106–30 mm. PBM simulations suggest that the KK model predicts identical evolution of the particle size distribution to that by the Austin model prior to scale-up. Upon scale-up, the differences are relatively small. Hence, modification of the exponents in the Austin’s scale-up methodology is not warranted for scale-up with the KK model. Overall, this study has established the similarity of both models for simulation and scale-up.

[Display omitted] • Breakage of coke, iron ore lump, sinter, briquette and pellet studied. • Sinter and lump have low breakage strength; coke and pellet have high. • Coke and pellet suffer limited weakening and surface breakage. • High fines generation from simulation of degradation with briquette and lump ore. • Low fines generation from simulation of degradation with coke and pellet. Mechanical degradation of steelmaking materials can have significant economic and environmental implications. Such degradation typically occurs as result of impacts during transportation and handling from their production site to the steelmaking furnace, in operations that include transfers in chutes, ship loading, stockpiling, reclaiming, wagon loading and discharging, etc. Predicting the extent of such degradation and attempting to prevent it, is worthwhile. Fortunately, mechanical degradation during such operations can now be predicted using different approaches, but a proper breakage model is required. The work presents results from single-particle breakage tests of iron ore lump, sinter, briquette, and pellet samples, besides coke, followed by fitting parameters of the Tavares UFRJ Breakage Model. These are then used to simulate degradation in a hypothetical handling circuit. Predictions demonstrate the high susceptibility of iron ore lump and briquette to fines generation, when compared to the other materials, and the occurrence of conditioning for briquettes and sinter, which is the increase in strength of particles surviving handling. Iron ore pellets and coke remained comparatively unaffected by the handling operations simulated, which is explained by their greater resistance to either body or surface breakage. [ABSTRACT FROM AUTHOR]

In this work, we develop a micro-mechanics inspired constitutive model for lightly cemented granular materials, whose internal variables have a clear physical interpretation. It builds on our previous work, which was able to predict several aspects of the behavior of bonded geomaterials (e.g. , macroscopic stress–strain responses, localization patterns) but did not explicitly account for porosity nor could it predict dilatancy at low mean stress levels. In the present work, we extend the original formulation by Tengattini (2015), formulating a model that is able to predict the material response across a broad range of mean stress while maintaining the same number of parameters as the original model, all of which have a clear physical interpretation, which helps guide their calibration. [ABSTRACT FROM AUTHOR]

The complex problem of the spatial motion of the "trolley-beam" mechanical system is investigated. Three stages are considered: 1) movement of the beam on a bifilar suspension to the movable trolley; 2) movement of the beam after the breakage of one branch of the suspension; 3) movement of the beam after the breakage of the second branch of the suspension. The study was carried out by creating mathematical models for each stage of the system movement and then conducting a numerical experiment using computer algebra. The tension of the ropes is calculated at the first and second stages of the system movement. Their extreme values are determined. The obtained results will be used in the further study of the system to reduce the tension of the rope and oscillation amplitude and to prevent accidents.

A series of ring shear tests were conducted to investigate the ultimate particle size distribution of a carbonate sand. The tests were carried out under different stress levels, on three types of specimens: 1) uniformly graded specimens made of dry natural sand 2) remoulded specimens of the crushed sand after first shearing to large strains 3) specimens made of natural sand grains but with the same grading as in (2). The first series of tests on type (1), carried out to very large strains, led to apparently stable gradings, distinct for each stress level. Only limited additional particle breakage could be induced by remoulding the specimens after shearing (type (2)) and subjecting them to more shearing. Tests on specimens created at the apparently stable gradings (type (3)) but from the intact sand particles however led to significantly greater breakage. For the three types a stable, fractal grading was achieved. Analyses of the soil particles’ shape showed that the aspect ratio, sphericity and circularity reach a steady value at large strains, in parallel to reaching a stable grading. The mobilized angle of shearing resistance however was not significantly different in the different types of samples, suggesting the final grading dominates the behaviour.

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]

Macroalgae provide food and habitat to a diversity of organisms in marine systems, so structural damage and breakage of thallus tissue can have important ecological consequences for the composition and dynamics of marine communities. Common sources of macroalgal damage include breakage by hydrodynamic forces imposed by ambient water currents and waves, tissue consumption by herbivores, and injuries due to epibionts. Many macroalgal species have biomechanical designs that minimize damage by these sources, such as flexibly reconfiguring into streamlined shapes in flow, having either strong or extensible tissues that are tough, and having chemical and morphological defenses against herbivores and epibionts. If damage occurs, some macroalgae have tissue properties that prevent cracks from propagating or that facilitate tissue breakage in certain places, allowing the remainder of the thallus to survive. In contrast to these mechanisms of damage control, some macroalgae use breakage to aid dispersal, while others simply complete their reproduction prior to seasonally-predictable periods of damage (e.g., storm seasons). Once damage occurs, macroalgae have a variety of biomechanical responses, including increasing tissue strength, thickening support structures, or altering thallus shape. Thus, macroalgae have myriad biomechanical strategies for preventing, controlling, and responding to structural damage that can occur throughout their lives. [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 article is intended to study the destruction mechanism of yarns of different structures under different types of deformations that occur during their textile processing (weaving, knitting, etc.). Improving the wear resistance of yams is one of the main ways to determine the causes of their destruction in textile processing with their subsequent elimination. The significance of this problem is determined by the fact that increasing the reliability and endurance of yams is equivalent to increasing output without additional labor and material resources. The ability of yarns for textile processing is mainly determined by their mechanical characteristics in tension: tensile strength and elongation, endurance, longevity, cyclic elongation, and the like. In the regulatory documents, this ability is mainly assessed only by the indicators of tensile strength and elongation, which does not fully characterize their behavior in textile processing. Therefore, the study of the features of the yam destruction under different types of mechanical interactions, as well as the impact of their structure on the process of destruction, is relevant for predicting their endurance and developing a new range of textile fabrics. [ABSTRACT FROM AUTHOR]

Macroalgae provide food and habitat to a diversity of organisms in marine systems, so structural damage and breakage of thallus tissue can have important ecological consequences for the composition and dynamics of marine communities. Common sources of macroalgal damage include breakage by hydrodynamic forces imposed by ambient water currents and waves, tissue consumption by herbivores, and injuries due to epibionts. Many macroalgal species have biomechanical designs that minimize damage by these sources, such as flexibly reconfiguring into streamlined shapes in flow, having either strong or extensible tissues that are tough, and having chemical and morphological defenses against herbivores and epibionts. If damage occurs, some macroalgae have tissue properties that prevent cracks from propagating or that facilitate tissue breakage in certain places, allowing the remainder of the thallus to survive. In contrast to these mechanisms of damage control, some macroalgae use breakage to aid dispersal, while others simply complete their reproduction prior to seasonally-predictable periods of damage (e.g., storm seasons). Once damage occurs, macroalgae have a variety of biomechanical responses, including increasing tissue strength, thickening support structures, or altering thallus shape. Thus, macroalgae have myriad biomechanical strategies for preventing, controlling, and responding to structural damage that can occur throughout their lives.