Breakage Patterns Research Articles

Computed Tomography-Driven Analysis of Particle Breakage Using a Coupled FDM-DEM Approach

This study proposes a refined approach for simulating the mechanical behavior of soils under high stress by integrating the Finite Difference Method-Discrete Element Method (FDM-DEM) with in-situ experiment. This novel framework incorporates advanced technologies such as flexible membrane and X-ray computed tomography (CT) to enhance the predictive capabilities of the simulation with physical insight. The FDM-DEM model adeptly simulates irregular particle shapes, capturing their interactions and the dynamics of particle breakage. The use of flexible membrane within the model further enriches this approach by enabling the capture of deformation responses in granular materials during shearing. Moreover, the adoption of CT technology facilitates continuous optimization of the simulation process. Validation through in-situ experiments has confirmed the model's effectiveness. The ability of the model to predict areas of high stress concentration—and their correlation with observed particle breakage patterns—underscores the utility of the enhanced FDM-DEM framework as a robust predictive tool for understanding the behavior of granular materials under shearing.

Numerical and experimental blast response of multilayer laminated glass panels

Laminated glass is used in high-security buildings to mitigate the effects of blasts and ballistic loadings. The multi-layered composition of the laminated glass (LG) panels allows the glass panes to crack and undergo large deflections while preventing glass shards from spalling by mostly remaining attached to the polymeric interlayer. To characterize multilayer LG panels under blast loading, it is essential to develop their static resistance response under uniform loading. A full-scale water chamber was used to experimentally evaluate the quasistatic response to the failure of the multilayer LG panel systems under uniform pressure. The influence of different polymeric interlayer types on the response of multilayer LG panels was studied. Also, the glass breakage patterns and deflections exhibited by various multilayer glass configurations were investigated. The response of LG panels under blast was developed using ANSYS AUTODYN, which was verified using field experiments. LG panels with an Ethylene Vinyl Acetate (EVA) polymeric interlayer experienced the most dynamic deflections, whereas LG panels with an ionoplast SentryGlas® (SG) polymeric interlayer displayed the least dynamic deflections. The results indicated that multilayer LG systems provide higher blast resistance compared to double-layer systems; the additional layers can help reduce glass breakage and maintain structural integrity. Multilayer LG system’s SG interlayer enhanced blast protection by allowing load transfer and ensuring uniform load distribution between glass layers.

Experimental replication of early human behaviour in bird preparation: a pilot-study focusing on bone surface modification and breakage patterns

The origin of complex behaviour amongst early humans is a subject of heated debate within the scientific community, and the study of small prey remains has become a significant aspect when examining such modern behaviour. Nonetheless, the consumption of small prey by human populations poses analytical difficulties due to the often negligible, or entirely absent, traces on bone surfaces. To address this difficulty, an experimental study focusing on terrestrial avifauna has been prepared, and here we present a preliminary phase of this research. The aim is to distinguish potential modifications on bird bone surfaces and fracture patterns that might facilitate the recognition of human manipulation of avian skeletal remains. Building upon the challenges encountered in the study of archaeological findings recovered from recent excavations in Iberian Middle Palaeolithic sites, the experimental protocol was formulated to encompass the processing of two uncooked and three roasted birds; and the lithic use-wear analysis of the flint flake used in the processing of raw birds. The results showcase distinct patterns of bone surface modifications and breakage between cooked and uncooked birds. Higher numbers of cut marks and manual disarticulation breaks are found on raw animals, whereas roasted animals show no cut marks, local-specific burns and higher bone loss. This pilot-study provides a baseline for future research to further explore the role of avifauna in Neanderthal subsistence and food processing, which may help highlight cultural choices.

Acoustic signals associated with the multifractal breakage patterns of brittle and crispy foods

Food breakage is an important issue in industry and is coupled to acoustic signals. The aim of this work was to analyse the breakage phenomenon with time in commercial crispy and brittle foods, using acoustic techniques and mechanical-textural features using Digital Image Analysis (DIA) and fractal analysis. Breakage patterns were coupled to the acoustic signals of six brittle foods by capturing the audio during breaking and then, applying DIA to audio signals and breakage patterns, which depicted multifractal spectra. Results showed that samples with less irregular acoustic patterns presented higher spectrum amplitudes and low generalised fractal dimension (GFD) (1.245 ± 0.045) and lacunarity (Ʌ) (0.269 ± 0.209) while materials presenting the largest irregularity had shorter spectrum amplitudes and depicted high GFD (1.656 ± 0.177) and Ʌ(0.745 ± 0.007). For global analysis of the transverse and longitudinal rupture pattern, four breakage zones were defined. In all cases, multifractal breakage patterns were associated to multifractal acoustic signals.

The archaeology of shellfishing practices on Ua Huka, Marquesas Archipelago (French Polynesia)

AbstractShellfish remains are ubiquitous to coastal archaeological sites in the Marquesas but have seldom been the focus of dedicated investigations into their contribution to past diet and daily life. On the island of Ua Huka, in the northern group of the archipelago, people have consumed a variety of shellfish since their arrival on the island around the early 12th century AD. By analysing assemblages from five coastal sites spanning from the early settlement until the 18th century and using an archaeomalacological approach (precise taxonomic identification, coupled quantification methods, observation of taphonomic processes, biometry), we attempt to recount the exploitation processes of this resource, from the initial gathering stage to the final discarding of the shell. We further explore inter‐site and temporal variability in prey choice. Coupled with ethnographic accounts from European observers and insightful testimonies from current inhabitants of the island regarding present‐day practices, we highlight the persistence of choices regarding species selection, breakage patterns and cooking processes on an island that has seen major subsistence changes since European contact.

The 7th Bishop Lecture: The mechanics of coarse-grained geomaterials at meso- and micro-scales

In order to move towards discrete analyses of soil behaviour, we need to develop a new range of apparatus and testing techniques. The lecture describes attempts to develop these new apparatus and presents data for a range of coarse-grained geomaterials at the single particle scale. The roles of the particle morphology and hence geological origin are discussed and are shown to influence both the contact mechanics and particle breakage behaviour. The mechanics of single particles are shown to be more complex than generally assumed and will require new means of modelling to account for the significant plasticity that occurs at particle contacts and patterns of breakage that are strongly influenced by the origins of particles and their effect on their morphology.

Resolving taphonomic and preparation biases in silicified faunas through paired acid residues and X-ray microscopy.

Paired petrography and acid maceration has shown that preferential silicification of shelly faunas can bias recovery based on taxon and body size. Here, silicified fossils from the Upper Ordovician Edinburg Formation, Strasburg Junction, Virginia, USA, were analyzed using X-ray tomographic microscopy (μCT) in conjunction with recovered residues from acid maceration of the same materials to further examine sources of potential bias. Results reveal that very small (<~1 mm) fossils are poorly resolved in μCT when scanning at lower resolutions (~30 µm), underestimating abundance of taxa including ostracods and bryozoans. Acid maceration, meanwhile, fails to recover poorly silicified fossils prone to disarticulation and/or fragmentation during digestion. Tests for patterns of breakage, however, indicate no significant size or taxonomic bias during extraction. Comparisons of individual fossils from 3-D fossil renders and maceration residues reveal patterns of fragmentation that are taxon-specific and allow the differentiation of biostratinomic and preparational breakage. Multivariate ordinations and cluster analyses of μCT and residue data in general produce concordant results but indicate that the variation in taxonomic composition of our samples is compromised by the resolvability of small size classes in μCT imaging, limiting the utility of this method for addressing paleoecological questions in these specific samples. We suggest that comparability of results will depend strongly on the sample size, taphonomic history, textural, and compositional characteristics of the samples in question, as well as μCT scan parameters. Additionally, applying these methods to different deposits will test the general applicability of the conclusions drawn on the relative strengths and weaknesses of the methods.

Abstract A034: Development of a novel class of genomic biomarkers through mathematical modeling of cancer genome contiguity

Abstract Introduction: Chromosomal instability (CIN) is a hallmark of cancer aggressiveness. However, in lung adenocarcinoma (LUAD) the most common methods for measuring genomic instability, such as the weighted Genome Instability Index (wGII), are not reliable predictors of patient outcomes. The wGII measures the portion of the genome altered by copy number variation (CNV). The wGII quantifies aneuploidy but ignores other properties of CNVs such as their length distribution. We hypothesized that quantification of genome contiguity may overcome the limitations of wGII and help identify novel prognostic biomarkers. Method: We develop a novel measure of CIN based on mathematical modeling of genome breakage patterns. Utilizing segmented CNV profiles we infer two properties of the genome breakage process – its intensity and dispersion. Intensity is proportional to the number of genome breakpoints and is estimated by the total number of CNV segments. Dispersion quantifies spatial dependence of breakpoints over a wide range of genomic scales. It is computed by Ripley’s K-function which compares the distribution of breakpoints with a random Poisson point process. Jointly, intensity and dispersion, which we term the weighted Genome Contiguity Index (wGCI), estimate the contiguity of the genome. We contrast the wGCI with a heuristic score based on quantiles of segment lengths. Results: We sought to evaluate the association between the wGCI and patients’ survival in a proteogenomic cohort of 215 primary LUAD tumors profiled using whole-genome sequencing (WGS). In support of our hypothesis, we observed that patients had significantly better outcomes if their tumor genomes had longer segments compared to those with a high degree of fragmentation (P=0.014). Utilizing the wGCI, we found that tumor genomes with dispersed breakage (and low contiguity) were associated with worst outcomes (P=0.01). To identify mechanisms associated with dispersed breakage patterns we compared genomic features of the two groups. We found that LUAD tumors with highly fragmented genomes have a higher rate of TERT amplifications (P=0.005) and increased TERT RNA expression (P=2e-6). These tumors are also enriched for TP53 mutations (P=2e-16) and MYC amplifications (P=0.01). Given the cost and practical challenges of clinical WGS we leveraged mass-spectrometry proteomics to identify protein biomarkers. We found IGF2BP3 to be significantly upregulated (P=0.0006) in highly fragmented tumors and to be associated with worse outcomes (P=0.011). We use immunohistochemistry (IHC) to develop and validate IGF2BP3 as a prognostic biomarker in independent lung cancer cohorts. Conclusion: We introduced a novel quantitative measure of CIN that uniquely captures the impact of chromosome breakage on LUAD patients' clinical outcomes. Further, we identified upregulation of IGF2BP3 as a proxy to identify fragmented genomes using IHC. Our work underscores the value of mathematical modeling of genome breakage patterns to develop complex genomic biomarkers. Citation Format: Noshad Hosseini, Rahul Mannan, Alexey Nesvizhskii, Saravana Dhanasekaran, Marcin Cieslik. Development of a novel class of genomic biomarkers through mathematical modeling of cancer genome contiguity [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: DNA Damage Repair: From Basic Science to Future Clinical Application; 2024 Jan 9-11; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2024;84(1 Suppl):Abstract nr A034.

Breakage behavior of corn kernels subjected to repeated loadings

Studying the breakage behavior of corn kernels subjected to repeated compressive events, including at low frequency and low strain rate, are important for the development of breakage models for prediction of kernel breakage in handling and processing machines. The main purpose of this study was to identify the breakage behavior and mechanism of weakening of corn kernels under repeated loadings as affected by their moisture content and kernel thickness. Corn kernels at four moisture content levels (8.20%, 11.95%, 16.00%, 20.02%) and in four thickness ranges were subjected to repeated compressive loading between two parallel steel plates in quasi-static regime at a constant loading rate of 2 mm/min (strain rates from 4.7 × 10−3 to 1.0 × 10−2). Conducted experiments allow to observe the different grain breakage patterns, identify the crack initiation and its development, describe the weakening of kernels by changes in the total specific energy, plastic and elastic deformation energies, and the number of loading cycles to break (breakage probability) the kernels. The results indicate that the breakage models describing the damage and weakening of grains in terms of changes in the total and strain energy or changes in the stiffness can be used for understanding the effect of moisture content and thickness on breakage of corn kernels.

Novel synergistic cross-linking ameliorate ready-to-eat sea cucumber deterioration and its quantum chemical analysis

Synergistic cross-linkers could improve the taste acceptability of ready-to-eat sea cucumber (RSC). Besides, the hardness of RSC was increased by 331.00% and 266.87% after synergistic cross-linking. Synergistic cross-linking treatment could ameliorate the non-enzymatic degradation of RSC collagen and polysaccharides. Gaussian calculations results showed that dipeptides containing asparagine residues may have different reaction pathways. The main cleavage pathways of CH3CO-Asn-Gly-NHCH3 (NG) might be water-assisted side chain cyclization, stepwise cyclamide hydrolysis via a Gemdiol Intermediate, deamination, and peptide bond breakage. The relative free energy of cyclamide hydrolysis process of NG was increased by 8.2 kcal/mol after synergistic cross-linking. The mass spectrometry results showed that typical peptides could cleavage at NG, CH3CO-Asn-Lys-NHCH3 (NK) and CH3CO-Asn-Leu-NHCH3 (NL) sites after heating, which justified the breakage pattern of peptides in Gaussian calculations. It can offer a comprehensive theoretical basis for the processing of the ready-to-eat sea cucumber with storage stability.

Oblique impact breakage unification of nonspherical particles using discrete element method

Particle breakage commonly occurs during processing of particulate materials, but a mechanistic model of particle impact breakage is not fully established. This article presents oblique impact breakage characteristics of nonspherical particles using discrete element method (DEM) simulations. Three different particle shapes, i.e. spherical, cuboidal and cylindrical, are investigated. Constituent spheres are agglomerated with bridging bonds to model the breakage characteristics under impact conditions. The effect of agglomerate shapes on the breakage pattern, damage ratio, and fragment size distribution is fully investigated. By using a newly proposed oblique impact model, unified breakage master surfaces are theoretically constructed for all the particle shapes under oblique impact conditions. The developed approach can be applied to modelling particulate processes where nonspherical particles and oblique impact breakage are prevailing.

Study on mechanical property and breakage behavior of tunnel slag containing weak rocks as road construction material

In the construction of roadbeds in mountainous areas, crushed rock slag (CRS) generated by tunnel blasting is usually reused as road construction material to reduce environmental pollution and construction costs. A series of large-scale drained triaxial tests were conducted to investigate the mechanical behavior of CRS subjected to static and traffic loading. The static triaxial tests determined the maximum stress level that can be applied to the cyclic test. The cyclic triaxial test analyses the influence of cyclic stress amplitude and confining pressure on the cumulative strain of CRS material. The particle breakage of the sample under various conditions after cyclic loading was discussed, and the relationship between the relative breakage index and the final accumulated strain was analyzed. Test results indicated that with the increase in confining pressure, the peak strength of the material exhibits a continual enhancement, while the expansion behavior experiences a gradual attenuation. In the range of static failure strength, the increase of cyclic stress level will significantly increase the accumulated axial strain rate. After the cyclic loading, the particle breakage patterns are similar under different confining pressures. A good power function relationship exists between the relative breakage index and final axial strain, and further derivation of the functional expression of the relative breakage index and both cyclic stress ratio and confining pressure.

Prey body size generates bias for human and avian agents: Cautions for interpreting small game assemblages

Identifying the accumulating agent(s) of small animal assemblages at archaeological sites is challenging given the range of behaviors, skeletal plans, and body sizes of prey species as well as the range of potential predators. Although mammalian carnivores, raptors, and humans are considered typical predators of small game, there are many contexts—especially in island ecosystems—where humans and raptors are the primary agents for small animal assemblages in the absence of mammalian carnivores. Moreover, smaller animals tend to range in body sizes in these geographically restricted ecosystems. This study aims to broadly explore: 1) how small animal body size affects the taphonomic signature(s) of human and avian predation; and 2) how human and avian-generated small game assemblages compare with one another. To investigate these questions, this study compared the resulting taphonomic patterns of small animal predation by raptors and humans using data collected during a controlled-feeding experiment and an observational study, respectively. In the controlled-feeding experiment, deceased laboratory rats (Rattus norvegicus domestica) (50–500 g) were fed to two Milky Eagle Owls (Ketupa lacteus), one King Vulture (Sarcoramphus papa), and two Lappet-Faced Vultures (Torgos tracheliotos). In the observational study, we explored how humans processed various species of small prey ranging in body mass (80–5000 g) by analyzing anthropogenic modifications (i.e., cutmarks, tooth marks, burning). The resulting small animal assemblages were analyzed post-consumption for skeletal element representation, fragmentation and breakage patterns, and bone surface modifications. Results show that small prey body size significantly affects pre-depositional patterning in terms of skeletal element survival, butchering intensities, and cutmark frequencies. Furthermore, our experimentally generated assemblages show that breakage, fragmentation, and element relative abundance patterns can be used to distinguish between human and avian-accumulated assemblages in the archaeological record.

Impact Resistance of 3D-Printed Continuous Hybrid Fiber-Reinforced Composites.

Improving the resilience of 3D-printed composites through material extrusion technology (MEX) is an ongoing challenge in order to meet the rigorous requirements of critical applications. The primary objective of this research was to enhance the impact resistance of 3D-printed composites by incorporating continuous hybrid fibers. Herein, continuous virgin carbon (1k) and Kevlar (130D and 200D) fibers were used with different weight and volume fractions as reinforcing fibers to produce hybrid and non-hybrid composites for impact resistance testing to obtain energy absorption with different impact energies: 20 J, 30 J, 40 J, and 50 J. Moreover, 0°/90° fiber orientations were used. Hybrid composites with combinations of PLA + CF + 130D KF and PLA + CF + 200D KF showed higher impact resistance, less damaged areas (71.45% to 90.486%), and higher energy absorption (5.52-11.64% more) behaviors compared to PLA + CF non-hybrids. CT scan images provided strong evidence to resist the fracture and breakage patterns, because the stiffness and elongation properties of the fibers acted together in the hybrids specimens. Furthermore, positive hybrid effects of the PLA + CF + KF hybrids also showed an ideal match of toughness and flexibility in order to resist the impacts. In the future, these hybrids will have the potential to replace the single type of composites in the fields of aerospace and automobiles.

Non-Ceramic Site of Shamanka 8 on the Southern Coast of Baikal Lake

Purpose. The southern coast of lake Baikal is a territory known in Siberian archaeology for its Kitoi cemeteries. Besides burials of the Shaman capes there are some Neolithic and Bronze age complexes at Circum–Baikal railway. In 2012 it the first non-ceramic site was discovered in South Baikal, which was named Shamanka 8. This paper presents the assemblage of this complex and discusses its chronological and cultural features.Results. The Shamanka 8 site is located on the top of the third hill of the Shaman cape. The cultural layer lies under the Holocene Optimum sediments. The site stratigraphic structure is characterized by compression. There is no bone fragments and ceramic. For lithic knapping, mainly local raw material (quartz) were used. The quartz assemblage has such features as poor formal standardization, high degree of flake fragmentation, cores with the orientation of fracture plane relative to the longitudinal axis, bipolar reduction. All of these specifics are explained by uneven fracture characteristics and bad workability of quartz, as well as its breakage patterns. Some artifacts, including single non-quartz tool, suggest that there may be a connection between the Shamanka 8 site and the industries of the Final Paleolithic sites in the Northern Baikal region and the Irkutsk region. Quartz small knife (?), carinated end-scraper and tubular core have analogies in the 2nd cultural layer of the Kurla II site, dated by 13.5 uncal kya. Similarly dated quartz components of Nirikan I and flint tool-kit of Verkholenskaya Gora I include other cultural link types.Conclusion. The similarity in the morphology of some tools with Final Paleolithic counterparts and stratigraphic position of finds allow us to assume the Final Sartan age of the Shamanka 8 site and dates it to the Bølling – Allerød warming. However, in the absence of direct radiocarbon dating, an Early Holocene/Early Neolithic attribution of the site is also possible. Further studies may help resolve this issue.

The Evolution of Paleolithic Hunting Weapons: A Response to Declining Prey Size

This paper examines the hypothesis that changes in hunting weapons during the Paleolithic were a direct response to a progressive decline in prey size. The study builds upon a unified hypothesis that explains Paleolithic human evolutionary and behavioral/cultural phenomena, including improved cognitive capabilities, as adaptations to mitigate declined energetic returns due to a decline in prey size. Five selected case studies in Africa and Europe were analyzed to test this hypothesis, focusing on the relative presence of megaherbivores (&gt;1000 kg) in the transition between the Acheulean/Early Stone Age and the Middle Paleolithic/Middle Stone Age. The findings indicate a decline in megaherbivores’ presence and biomass contribution in the studied transition period associated with the introduction of Levallois technology. We review the evolution of hunting weapons, including wooden-tipped and stone-tipped spears and bows and arrows. Analysis of tip size and breakage patterns indicate a reduction in point size over time, aligning with the declining prey size. We propose that changes in hunting weapons and strategies were driven by the practical and ontological incentives presented by the availability and size of prey. Developing smaller, more precise weapons required increased cognitive capacities, leading to the parallel evolution of human cognitive abilities.

A breakage model for DEM based on a probabilistic particle replacement with Voronoi fragments

Due to mechanical stress, bulk material is crushed and fines are produced. This can either be desired in comminution processes or undesired in conveying and storage processes. In this work a novel breakage model for the Discrete Element Method is presented to allow a prediction of the resulting particle size distribution after damaging events. The breakage model is based on a probabilistic particle replacement strategy. Depending on the load, the initial particle is replaced by a breakage pattern tessellated with the Voronoi algorithm. Replacement probabilities and breakage patterns follow results from breakage tests. In contrast to other replacement models, mass and volume remain constant. Initial particles are polyhedral and can be of any shape. Crushing processes with multiple breakage can be simulated. The computational scheme is described in detail. The model was verified and validated with trials of shatter tests and two conveying processes with blast furnace sinter from two different industrial partners.

DEM multi‐scale insights on the pre‐failure behavior of mature structured sands: Influence of bond type, amount, breakage pattern and heterogeneity

AbstractA new approach in the calibration process of DEM samples of structured sand is presented. Micromechanical‐based experimental data are interpreted to develop a failure model and a range of input parameters in the DEM analyses are incorporated considering strong and a weak bonds in the simulated samples. Subsequently, the numerical samples correspond to analog mature structured soil/sandstone in terms of both compositional and textural maturity, and the study focused on the small‐to‐medium strain shear modulus and on providing multi‐scale insights of the simulated materials. The heterogeneity of the structured sand is incorporated based on Gaussian and Weibull distributions of the contact properties and four major parameters are examined including bonding amount/content, bonding strength, heterogeneity, and confining pressure. The numerical results showed, at the macroscopic level, agreement with respect to a number of element‐size experiments on sandstones which were re‐analyzed in the present work, in terms of stiffness—pressure relationship, stiffness reduction, and occurrence of the yield point associated with the initiation of bond breakage. It was shown that even though the bond strength and amount of bonds are important influencing factors on the macroscopic behavior of the structured sand, the incorporation of heterogeneity can significantly alter the interpretations of the microscopic involved mechanisms. This unveils that the implementation of “average” input parameters cannot capture well the contributing mechanisms which influence the deformation characteristics of structured soils and sandstones.

Tailorable mechanical and energy absorption behaviors of 3D printed continuous hybrid fiber reinforced composites

Abstract3D printing of continuous fiber‐reinforced thermoplastic composites (CFRPCs) has expanded potential structural application in recent years. However, it is still challenging to tailor the mechanical and energy absorption properties of 3D‐printed composites to fulfill the requirements for critical application conditions. Herein, hybrid fiber (HF) reinforced composites have been prepared by 3D printing of CFRPCs and investigated on the mechanical and energy absorption behaviors. Continuous virgin carbon fibers (CF), Kevlar fibers (KF) (130 Deniers (D), and 200 Deniers (D)) and E‐glass fibers (GF) were used as reinforcing fibers to produce hybrid and non‐hybrids composites. Hybrid composites with different combination of CF + GF, CF + 130D KF, and CF + 200D KF showed tailorable behaviors, such as flexural modulus (16,691.74, 20,372.38, and 19,017.44 MPa), tensile modulus (15,022.6, 16,269.41, and 15,320.58 MPa). And energy absorption behaviors of CF + 130D KF and CF + 200D KF were tailored in both tensile (18,865.25 and 20,302.07 N‐mm, respectively) and bending (3594.54 and 3570.80 N‐mm, respectively) tests compared to other composites which will be ideal for energy absorption applications. Moreover, CF + GF showed tailored strength which could be used in the need of high stiffness. SEM images were providing strong evidence to resist the fracture and breakage patterns, by tailoring the stiffness and elongation properties of fibers in hybrids specimens. Furthermore, positive hybrid effects of CF + KF hybrids in tensile and bending tests were also showing an ideal match of toughness and flexibility. In future, these cost and weight effective hybrids will have potential to apply in aerospace and automobile.

Aspects of Aktuo-Paläontologie of the rocky beaches of the eastern Isle of Mull, UK

Conglomerates are, commonly, only poorly fossiliferous at best. Yet beaches with common lithic clasts can be used to model the taphonomy of fossils in conglomeratic settings. Four beaches on the east coast of the Isle of Mull, Inner Hebrides, are clast-rich, with lithic pebbles, cobbles and boulders, but poor in shells, many of which are poorly preserved. There is ample evidence of shells being bored and encrusted, yet many or most of these were infested after death of the host. Of the ‘boring trinity’, Caulostrepsis Clarke, Entobia Bronn and Gastrochaenolites Leymerie, so typical of the Trypanites Ichnofacies around Britain's coasts, only the last ichnogenus was not present, most probably owing to the absence of suitable mobile substrates (such as limestone cobbles and oysters). Encrusters including Balanus , serpulids and spirorbids show different patterns of preservation, probably owing to multiple factors. Bored wood ( Apectoichnus ) was found at only one locality, which may be due to hydrodynamic sorting. Whelk shells show a range of patterns of breakage, most probably caused by mechanical damage. But conglomerates commonly preserve fossil snails either complete or not at all. The results from these sites suggest that they represent an intermediate condition rarely preserved in the rock record.