Material Specimens Research Articles

Machine Learning-Based Fatigue Life Prediction of Functionally Graded Materials Using Material Extrusion Technology

In this study, the research investigates the prediction of fatigue life for Functionally Graded Materials (FGM) specimens comprising Polylactic acid (PLA) and Thermoplastic Polyurethane (TPU). For this, Machine learning (ML) techniques, including Random Forest (RF), Support Vector Machine (SVM), and Artificial Neural Network (ANN) are utilized. A predictive in-house code is developed for each technique, thereby facilitating the fatigue performance of layered deposited specimens subjected to varying cyclic loadings. In order to verify the effectiveness of the ML technique, a comparative analysis among all is reported based on empirically determined fatigue life obtained values. RF is proven to be the most suitable technique with minimal error percentage in obtained results with optimally synchronized data sets in a minimum time frame. Subsequently, the application of ML in those predictions is reported for future aspects in augmenting the operational efficiency associated with fatigue life prediction.

A new method of interlayer shear performance evaluation for permeable composite pavement (PCP) in laboratory

Permeable composite pavement (PCP) has been increasingly applied for road design and construction. However, interlayer shear resistance is still a challenge for the road performance improvement of PCP. This paper presents a new method of interlayer shear performance evaluation for PCP with a self-made molding device and shear clamp. PCP test slabs are made in two ways, the porous asphalt mixture + impermeable and + permeable concrete layer, named PAIC and PAPC, respectively. The interlayer shear test of PCP slab specimens is conducted under different bonding material types, dosage, temperature, and interlayer contact interface morphology. The results indicate that: (1) The type and amount of bonding materials influence the interlayer shear performance of PCP slabs. The stronger the bonding property of the interlayer material, the greater the interlayer shear strength (ISS) of the PCP. There is the best amount of the same material as the interlayer bonding material. The optimum dosage of styrene-butadiene-styrene (SBS), matrix, and spraying cationic emulsified (PCR short in Chinese) asphalt on the PAIC board is 0.8, 0.6, and 0.4 L/m2, respectively. However, the optimal amount for each bonding of the PAPC slab is 0.6 L/m2. (2) The temperature has a great influence on the ISS of the permeable composite slab due to asphalt being a temperature-sensitive material. For the two slabs, the ISS decreases with the increase in temperature, and even the ISS at 5 °C is 10 times that at 50 °C. (3) The interface morphology of interlayer contact affects the performance of ISS. For PAPC, the contact interface between the two materials is rougher, and the high friction between layers leads to the larger ISS. PAPC's ISS is at least twice that of PAIC. (4) A new method of interlayer shear performance evaluation for the optimization design and application of PCP has been proposed in the final. The method includes material design, specimen making, testing, and quick evaluation. This method has the potential to contribute to the development of PCP tests in the laboratory.

Practical Approach for Determining Material Parameters When Predicting Austenite Grain Growth under Isothermal Heat Treatment.

An investigation of austenite grain growth (AGG) during the isothermal heat treatment of low-alloy steel is conducted. The goal is to uncover the effect of time, temperature, and initial grain size on SA508-III steel grain growth. Understanding this relationship enables the optimization of the time and temperature of the heat treatment to achieve the desired grain size in the studied steel. A modified Arrhenius model is used to model austenite grain size (AGS) growth distributions. With this model, it is possible to predict how grain size will change depending on heat treatment conditions. Then, the generalized reduced gradient (GRG) optimization method is employed under adiabatic conditions to characterize the model's parameters, providing a more precise solution than traditional methods. With optimal model parameters, predicted AGS agree well with measured values. The model shows that AGS increases faster as temperature and time increase. Similarly, grain size grows directly in proportion to the initial grain size. The optimized parameters are then applied to a practical case study with a similar specimen size and material properties, demonstrating that our approach can efficiently and accurately predict AGS growth via GRG optimization.

EFFECT OF GEOMETRY AND SURFACE DISTRIBUTION OF HOLES ON SOUND AND LIGHT ABSORPTION PROPERTIES OF 3D-PRINTED PETG MATERIALS

Noise and lighting are significant factors that have an impact on our health, environment, production quality, etc. The purpose of this paper is to investigate sound and light absorption properties of 3D-printed polyethylene terephthalate glycol (PETG) material specimens that were manufactured with two types of holes, namely with circular and square-shaped holes. In addition, the holes were printed with different dimensions, depths, shapes, and surface spacings. Different factors influencing the material´s ability to absorb sound and light were evaluated in this paper. It was found in this study that the type of holes, their spacing and depth have a big influence on sound and light absorption properties of the investigated samples compared to the smooth PETG material.

An improved measurement of frequency-dependent shear properties of highly compliant materials using a dynamic Kibble’s method

While methods exist to characterize the Young’s modulus and loss factor of viscoelastic materials, there are fewer methods to characterize the shear modulus and loss factor in shear. We previously presented an experimental apparatus that applied dynamic torque on rod-like viscoelastic materials with diameters of 0.5 cm to 2 cm and lengths of 10 cm to 30 cm. The torque was applied using Lorentz forces and measured using a dynamic version of Kibble’s method (similarly, the Watt method). Here, we present a modified version of this apparatus that has several notable improvements over the previously reported version. Improvements include a stronger, more uniform magnetic field and a direct measurement of the angular response of the specimen using a laser and photo-diode configuration. Moreover, the direct measurement of the angular response eliminates the need to know other geometric quantities (such as the radius of the electromagnetic coil), which further reduces the uncertainty of the measured torque. The measurement of the angular response and applied torque are fit to models in order to determine the shear moduli and loss factor. We demonstrate this improved technique on rod-like specimens of different highly-compliant viscoelastic materials.

Determination of the strength characteristics of a flanged joint with a flat gasket and loose retaining rings using a 3-point bending test

To evaluate the effectiveness of determining the strength of loose rings made, polymer laminate, using a 3-point bending test of rectangular material specimens differing in form and dimensions from actual structural components.The analysis carried out indicated a method of quantitative evaluation that could be directly related to the operating conditions of the rings. A similarity relation between the critical states of the ring and the specimens subjected to bending tests was presented. The assumed hypothesis of maximum tensile stresses of the rigid outer laminate layers provided the basis for formulating a criterion for the allowable loads on the rings, depending on the assembly tension of the bolts and the operating pressure in the installation.The results of the bending tests, both in the elastic and failure range of the samples, confirmed the validity of the hypothesis about the proportionality of the breaking stresses in the ring and the bending, cuboid sample, made of a similar laminate.The area of dimensional optimisation of the joint with regard to its strength and stiffness criterion is indicated.The method provides a basis for evaluating the strength and tightness of a flange connection by means of experimental testing of specimens made of a laminate similar to the material of the rings. The results of the 3-point bend tests allow for the substitution of difficult tests of complex assembly components such as rings in a flanged connection, including the operating conditions of the connection in a pressure piping system.

Comparison of Repair Bond Strength of Bulk-fill and Conventional Composites With Different Bonding Systems

Background: One of the advantages of resin composites as a restorative material is their repairability. The purpose of the current study was to compare the repair bond strength of conventional and bulk-fill composites with different bonding systems. Methods: In this in vitro study, sixty cylindrical specimens of materials were prepared according to the six groups under study (two types of conventional Gradia Direct and N-Ceram Bulk-Fill Tetric composites and three bonding systems: Single Bond Universal and Clearfil SE Bond and Single Bond 2). The samples were divided into 6 groups of 10 Single Bond/Gradia Direct composite (G1), Single Bond/Tetric N-Ceram bulk-fill composite (G2), Clearfil SE bond/Gradia Direct (G3), Clearfil SE Bond/Tetric N-Ceram bulk-fill composite (G4), single bond universal/Gradia Direct composite (G5), and Single Bond Universal/Tetric N-Ceram bulk-fill composite (G6). Repair bond strength in each group was measured using the Universal Testing Machine (Hounsfield). All data were analyzed by SPSS 21 using ANOVA, Student’s t-test, and chi-square statistical tests (P<0.05). Results: The highest and lowest bond strength (15.81±2.44 and 14.02±1.57, respectively) belonged to the Clearfil SE Bond-Tetric N-Ceram and Single Bond (Etch & Rinse)-Gradia Direct groups, respectively. The ANOVA test results demonstrated no significant difference in the bonding strengths of the study groups (P=0.537). Conclusions: Bulk-fill composite Tetric N-Ceram, apart from the bonding system, had higher repair bond strength compared to the conventional Gradia Direct composite. It seems that self-etch bonding systems (Clearfil SE Bond and Single Bond Universal) have had more bond strength than etch and rinse bonding (Single Bond 2 bonds).

B-001 Method Development of C-Reactive Protein in the Serum of Non-Human Primates

Abstract Objective The objective of this study is to validate C-Reactive Protein (CRP) measurement in Non-Human Primate (NHP) serum using the ADVIA 1800 analyzer. Methods CRP was validated in NHP serum using the ADVIA 1800 analyzer. Validation testing included intra-assay precision, inter-assay precision, accuracy, linearity of dilution, limit of quantitation (LOQ), limit of detection (LOD), reference interval, carry-over, correlation, and stability. Samples were collected into tubes containing no anti-coagulant. Intra-assay precision was determined by analyzing two biological samples and the two quality control levels of Bio-Rad Lyphochek Immunology Plus Control 10 consecutive times (in duplicate) within a single run. Inter-assay precision was determined by analyzing two biological samples and the two quality control levels of Bio-Rad Lyphochek Immunology Plus Control six times for six days over a 10-day period. Accuracy was calculated using the data obtained from the inter-assay precision testing. For linearity of dilution, calibrator material and diluted specimen samples were analyzed in duplicate. The LOQ was determined by diluting the low-level calibrator material to produce a value at the low end of the reportable range. Diluted material was tested six times within the same run. The LOD was determined by assaying the appropriate blank 10 times within the same run. The reference interval was determined by analyzing 21 serum samples. Correlation between the two ADVIA 1800 analyzers was determined by assaying 10 samples on both analyzers once. The carry-over of the assay was determined by analyzing the high-level quality control material followed by the low-level quality control material. Stability of serum samples was tested at room temperature, refrigerated, and frozen (at -20°C) for various durations of storage. Results Results show that measurement of CRP in NHP serum met the acceptance criteria for intra-assay precision, inter-assay precision, accuracy, linearity of dilution, limit of quantitation, carry-over, and stability. For intra-assay precision in specimen and control material, the %CV was within ±20%. The inter-assay precision for specimen and control material %CV was within ±20%. The total error observed (TEobs) was within ±20% for accuracy in control material and the obtained mean was within the acceptable range specified by the manufacturer. For linearity of dilution, the coefficient of determination was ≥0.9000 and TEobs for each dilution and calibrator level was lower than 20%. The LOQ was set at the lowest concentration for which the TEobs was within ±20%. The LOD was calculated by adding the mean concentration obtained and three times the standard deviation. The reference interval was set to the 2.5th to 97.5th percentile interval using Excel software. The carry-over was acceptable as it was ≤2%. Correlation between the two ADVIA 1800 analyzers was determined to describe any bias in result interpretation. Stability at all storage conditions was found to be acceptable with a mean %difference within ±20%. Conclusion CRP in NHP serum met the acceptance criteria for all required validation parameters. The ADVIA 1800 analyzer can be used for preclinical studies to test CRP in NHP serum.

B-002 Method Validation of Cystatin-C in the Serum of Dogs

Abstract Objective The objective of this study is to validate the new Siemens Cystatin-C reagent for analysis of dog serum on the ADVIA 1800 analyzers. Methodology The ADVIA 1800 analyzer was used in the validation of Cystatin-C in Dog serum. Whole blood samples were collected in tubes free of anti-coagulant and centrifuged for 10 min at 2400 rpm. Serum was separated after centrifugation using appropriate separation techniques. Testing disciplines for the validation included intra-assay precision, inter-assay precision, accuracy, linearity, limit of quantitation (LOQ), limit of detection (LOD), reference interval, carryover, correlation, and stability. Intra-assay was determined by analyzing two biological samples and the three quality control levels of BioRad Liquichek Immunology Control 10 consecutive times (in duplicate) within a single run. Analysis of two biological samples and three levels of BioRad Liquichek Immunology Control six times for six days over a 10-day period was conducted to determine inter-assay precision. Accuracy was calculated using the data from the inter-assay precision testing. Specimen samples and Siemens Cystatin C-2 Calibrator were diluted and analyzed in duplicate for linearity. To determine LOQ calibrator was diluted to produce a value at the low end of the reportable range and tested six times within the same run. LOD was determined by assaying the appropriate blank 10 times within the same run. The reference interval was determined by analyzing 21 serum samples. Through analyzing 10 serum samples on both ADVIA 1800 analyzers correlation between analyzers could be determined. The carry-over of the assay was determined by analyzing the high-level quality control material followed by the low-level quality control material three consecutive times. Stability of serum samples was tested at room temperature, refrigerated, and frozen (at −20°C) for various durations of storage. Results The measurement of Cystatin-C in Dog serum met the acceptance criteria for intra-assay precision, inter-assay precision, accuracy, linearity of dilution, LOD, LOQ, carry-over, and stability as articulated in the results. The intra-assay precision and inter-assay precision in specimen and control material %CV was within ±20%. For accuracy the total error observed (TEobs) was within ±20% and the mean was within the acceptable range specified by the manufacturer. For linearity of dilution, the coefficient of determination was ≥0.9000 and TEobs for each dilution was lower than ±20%. The LOD was calculated by adding the mean concentration and 3 times the standard deviation. LOQ was set at the lowest concentration measured at which the %CV, %bias, and TEobs was within ±20%. The reference interval was set to the 2.5th to 97.5th percentile interval. The carry-over was accepted as it was ≤2%. Correlation between the two ADVIA 1800 analyzers was determined to describe any bias in result interpretation. Stability was found to be acceptable at all storage conditions with a mean difference within ±20%, except freeze/thaw #2. Conclusion Cystatin-C in Dog serum met the acceptance criteria for all required validation parameters. The ADVIA 1800 analyzer can be used for preclinical studies to test Cystatin-C in dog serum.

Nonlinearity of mechanical behavior of 3D-reinforced composites under compression

Modern technological capabilities make it possible to produce 3D spatially-reinforced for polymer composite materials. The tasks of experimental research and analysis of the deformation process of new composite materials for aviation purposes taking into account the nonlinearity of mechanical behavior become actual. The paper presents an experimental study of the mechanical compression behavior of composite material specimens made of 3D woven carbon fiber preforms using the pressure impregnation technology (Resin Transfer Molding method with a pairwise interlayer reinforcement and a longitudinal layer). Compression mechanical tests were carried out on specimens using a universal system of electromechanical testing Instron 5882 and a system of 3D analysis of displacement and strain fields on the surface. Tests were conducted in accordance with ASTM D 3410 recommendations and using specialized tooling. Consideration of nonlinearity parameter during experimental data processing is proposed. The importance of determining the values of critical deformation in compression as a parameter characterizing the moment of the beginning of fracture is noted. Comparison of carbon fiber composite materials made by the same technology from fibers and binders of different manufacturers has been carried out. The experimental diagrams "stress-strain" and their approximating dependences taking into account the nonlinearity function w are obtained. The type of functions w of the studied materials is defined, the linear approximation of dependence of functions w on deformation is substantiated. Values of strength limits, elastic modulus, nonlinearity coefficient and critical damage were obtained, statistical processing of the obtained results and their analysis were carried out.

Character state diversity of Litsea (Lauraceae) leaves in Cianjur Herbarium Hortus Botanicus Tjibodensis

Herbarium serves as a storage place for plants that have been preserved, both in the form of dry and wet preserves. The specimen material is useful in determining the taxonomic status or identity of a plant. Litsea is one of the genera of the Lauraceae tribe (kamper-kamperan) which has similar leaf morphological characters among the species in it or even with other genera that are still in one tribe. The study aims to explain the variation of leaf morphological characters of species of Litsea clan members derived from herbarium specimens of the Cianjur Herbarium Hortus Botanicus Tjibodensis (CHTJ) collection. The research method uses direct observation of specimens in a careful, detailed, high concentration, and still refer to the information data contained in the herbarium sheet. The results showed that the petiole length ranged from 0.7 cm to 3 cm, the petiole surface was hairy (glabrescent) and glabrous. Species of the genus Litsea have leaf shape (circumscriptio): oval (ovalis/ellipticus), elongated (oblongus), and lobed (lanceolatus); The leaf tip (apex folii) is pointed (acutus) in 5 species, and tapered (acuminatus) in 4 species, obtuse (obtusus) in 3 species; the leaf base (base folii) is rounded (rotundatus) in 4 species, obtuse (obtusus) in 5 species, and pointed (acutus) in 3 species; while the arrangement of leaf bones (nervatio or venation) is pinnate (penninervis). The species also have flat leaf margins (margo folii) (integer), with the leaf blade (intervenium) being paper-like and parchment-like, the leaf color is green, and the leaf surface has pilosus.

Comparative Analysis of the Influence of Mineral Engine Oil on the Mechanical Parameters of FDM 3D-Printed PLA, PLA+CF, PETG, and PETG+CF Materials.

Polymer materials and composites play a pivotal role in modern industry, prized for their durability, light weight, and resistance to corrosion. This study delves into the effects of mineral engine oil exposure on the mechanical parameters of 3D-printed materials created through fused deposition modeling (FDM). The research scrutinizes prototype materials under diverse environmental conditions, with a particular focus on the tensile parameters. The primary aim is to analyze and compare how mineral engine oil affects the mechanical parameters of four commonly used FDM 3D-printed materials: PLA, PLA+CF composites, PETG, and PETG+CF composites. In the case of the PLA specimens, the tensile strength decreased by approximately 36%, which, considering the 30% infill, remained acceptable. Simultaneously, the nominal strain at the point of breaking increased by 60.92% after 7 days and 47.49% after 30 days, indicating enhanced ductility. Interestingly, the PLA's Young's modulus remained unaffected by the oil. The 3D-printed PLA+CF materials exposed to 30 days of mineral engine oil displayed a substantial Young's modulus increase of over 49.93%. The PETG specimens exhibited intriguing behavior, with a tensile strength decrease of 16.66% after 7 days and 16.85% after 30 days, together with a notable increase in the nominal strain at breaking by 21.34% for 7 days and 14.51% for 30 days, signifying enhanced ductility. In PETG material specimens, the Young's modulus increased by 55.08% after 7 days and 66.27% after 30 days. The PETG+CF samples initially exhibited increases in tensile strength (1.78%) and nominal strain at breaking (6.08%) after 7 days, but later experienced an 11.75% reduction in the tensile strength after 30 days. This research underscores the critical role of material selection in oil-exposed environments and suggests avenues for future exploration, encompassing microstructural analysis, the long-term impact of oil exposure, and broader considerations related to environmental and oil-specific factors. It contributes to a deeper understanding of the intricate interactions between polymer materials and mineral engine oil, offering valuable insights that can enhance industrial applications.

Effect of layering strategy and prolonged water aging on masking ability of composite resins

Statement of problemLayered composite resins may adequately mask discolored substrates. However, whether color changes that occur over time affect masking ability is unclear. PurposeThe purpose of this in vitro study was to investigate the effect of layering and water aging on the masking ability of 2 composite resins. Material and methodsDisk specimens (1.5 mm-thick and shade A1) from Charisma Diamond (CD) and Filtek Z350XT (Z350) were made according to the composite resin shade combination used in the layering strategies: bilayer for CD (enamel/dentin) and for Z350 (enamel/body and enamel/dentin) and trilayer for Z350 (enamel/body/dentin) (n=5). Color measurements were obtained with a spectrophotometer over an A3.5 ceramic substrate, and the whiteness index for dentistry (WID) was calculated. The specimens were aged in water at 37 °C and evaluated at different times: 24 hours, 1 week, 1 month, 2 months, 6 months, 12 months, 18 months, and 24 months. CIEDE2000 color differences (ΔE00) and WID differences (ΔWID) were calculated and interpreted by 50:50% color and whiteness perceptibility and acceptability thresholds. Changes among strategies and aging times were analyzed using the Kruskal-Wallis test (α=.05). Contrasts were made using the Mann-Whitney U test with Bonferroni correction (α=.001). ResultsΔE00 decreased from 24 hours to 2 months of aging. From 2 months onwards, ΔE00 increased for all layering strategies and times, without significant changes in lightness for CD (P>.004). Overall, for the CD restorative system, an increase in ΔWID was observed after 1 month of aging (P<.001), while for the Z350 restorative system, ΔWID decreased after aging (P<.001), except for the Z350 bilayer strategy (enamel + dentin) at 1 week and 2 months (P>.004). For all layering strategies and aging times, color differences were higher than the 50:50% perceptibility threshold for ΔE00 and, after 6 months, higher than the 50:50% acceptability threshold for ΔE00 and the 50:50% whiteness acceptability threshold. ConclusionsThe ability of the tested composite resins to mask a discolored substrate was affected by the layering approach applied and by prolonged water aging.

The effect of bedding planes on the bending strength of rock-like material and evaluation of the crack propagation mechanism

Bedding planes affects various material properties, including the bending strength and the crack propagation mechanism of rocks. In this paper, laboratory studies on rock-like material specimens were conducted to investigate the effect of bedding planes on the failure and crack propagation mechanism and to reduce the effect of secondary factors on the results. To this end, semi-circular bend (SCB) specimens were prepared with two concrete mixing designs using aggregate and geopolymer concretes as materials. Next, they were subjected to compressive and three-point bending tests. The crack propagation mechanism, changes in the bending strength, maximum fracture load, relative midspan displacement, fracture energy, and fracture toughness were analyzed for the anisotropic and isotropic specimens. Also, different bedding angles were examined for the anisotropic specimens. The results revealed that bedding planes generally affected the crack propagation mechanism and changed the fracture mode from pure opening mode for the isotropic specimens to mixed modes for different bedding angles. Hence, the strength and fracture parameters were generally smaller in the anisotropic specimens than in the isotropic ones. With an increase in the bedding angle in the specimens, the maximum fracture load and the fracture surface energy increased, and the midspan displacement behaved differently. Moreover, the fracture toughness displayed an increasing trend with increasing the bedding angle in the anisotropic specimens. The rate of changes in the parameters were different for different bedding angles. This may be attributed to the changes in the stress distribution and to the fracture and crack propagation modes in the anisotropic specimens compared to the isotropic ones.

Carbon footprint evaluation of routine anatomic pathology practices using eco-audit: Current status and mitigation strategies

Because of global warming, integrating an ecological dimension to the practice of pathology is crucial, as already performed in other medical specialties. The aim of the study was to estimate the greenhouse gas emissions (GHE) of one biopsy/surgical specimen hematoxylin-phloxine-saffron (HPS) slide, one frozen section examination, and one immunohistochemistry (IHC) slide, and to propose environmentally friendly recommendations.The different steps of the pathological procedures, from sample transport to slide/block destruction, were considered for the GHE evaluation. Consumables and reagents used at each step were noted, as well as the electricity consumption of the premises/equipment, specific wastes, and staff travel. The GHE analyses were performed according to the eco-audit method.The GHE attributable to one HPS slide of a biopsy, one HPS slide of a surgical specimen, one frozen section examination, and one IHC slide were 0.589 kgCO2e (CO2 equivalent), 0.618 kgCO2e, 1.481 kgCO2e, and 0.363 kgCO2e, respectively. For a one-year activity in the pathology department, the GHE for HPS was estimated at 91,897 kgCO2e, equivalent to 422,321 km of thermal car ride. The main GHE sources were staff travel for one biopsy HPS slide (34.2 %) and one surgical specimen HPS slide (32.6 %), materials (39.1 %) and staff travel (27.2 %) for one frozen section examination, and staff travel (28.2 %) and reagents and their packaging (44.9 %) for one IHC slide.The present study highlighted the most significant sources of GHE for routine practices in a pathology department, underlining that, from pathologists to policy makers, each actor has a responsibility to implement sustainable changes.

Characterization of dynamic confinement response of potting materials at different strain rates and temperatures

A Kolsky compression bar was modified with an instrumented confining tube for characterizing dynamic confinement response of materials at various strain rates. A thin film polyvinylidene fluoride (PVDF) force transducer was designed and integrated to the confining tube for direct in-situ measurement of confining pressure when the specimen is subjected to dynamic axial compressive load such that the mean stress-volumetric strain response of the specimen material is able to be determined. An environmental chamber was also implemented to the Kolsky compression bar for characterizing dynamic confinement response of materials at different environmental temperatures. After careful calibration of the instrumental confining tube, five different potting materials (EPON 828, EPON 828 filled with glass microballoons (GMBs), Sylgard 184, Sylgard 184 filled with GMBs, and expanded polystyrene (EPS) foam) were characterized with the modified Kolsky compression bar at different strain rates and environment temperatures. The effects of strain rate and temperature on the mean stress-volumetric strain response were determined for all five potting materials. Experimental uncertainties were also presented.

Checklist of newly-vouchered annelid taxa from the Clarion-Clipperton Zone, central Pacific Ocean, based on morphology and genetic delimitation.

We present a checklist of annelids from recent United Kingdom Seabed Resources (UKSR) expeditions (Abyssal Baseline - ABYSSLINE project) to the eastern abyssal Pacific Clarion-Clipperton Zone (CCZ) polymetallic nodule fields, based on DNA species delimitation, including imagery of voucher specimens, Darwin Core (DwC) data and links to vouchered specimen material and new GenBank sequence records. This paper includes genetic and imagery data for 129 species of annelids from 339 records and is restricted to material that is, in general, in too poor a condition to describe formally at this time, but likely contains many species new to science. We make these data available both to aid future taxonomic studies in the CCZ that will be able to link back to these genetic data and specimens and to better underpin ongoing ecological studies of potential deep-sea mining impacts using the principles of FAIR (Findable, Accessible, Interoperable, Reusuable) data and specimens that will be available for all. We include genetic, imagery and all associated metadata in Darwin Core format for 129 species of annelids from the Clarion-Clipperton Zone, eastern abyssal Pacific, with 339 records.

Parametric investigation of bonded composite joints under Mode II using a new methodology based on design of experiments

ABSTRACT In the pursuit of a sustainable future with limited resources and growing environmental concerns, adhesive joining stands out as a pivotal technology for the advancement of lightweight structures. This study aims to investigate the influence of various variables on the critical strain energy release rate in mode II (GIIc) for End-Notched Flexure (ENF) bonded composite joints, employing a new methodology based on Design of Experiments (DoE) approach. Two-dimensional finite element models of the ENF bonded composite joints are developed using commercial software, with all numerical models generated via Python™ scripts linked with AbaqusⓇ. Eleven design parameters related to the specimen geometry and material properties are systematically evaluated to determine the influence of each variable on GIIc. Numerical force–displacement curves are obtained, followed by the application of the Compliance-Based Beam Method (CBBM) to estimate the critical fracture energy in mode II, represented by a numerical envelope. The influence of each parameter is assessed using the main effect (ME) metric. The top five most influential variables affecting GIIc and CBBM are identified as the adhesive’s critical strain energy release rate in mode II (GIIc), effective laminate longitudinal elastic modulus (), adhesive thickness (tA), adherent thickness (h), and pre-crack length (). Furthermore, the study highlights the epistemic uncertainty associated with the geometric variables. Despite the limitations inherent in the computational model, the Plackett-Burman method consistently proves effective in conducting sensitivity analysis of the variables in the ENF test. These findings demonstrate promising prospects for the application of this procedure in the design of composite joint structures.

The Ball-on-Three-Balls strength test: Effective volumes and surfaces for Weibull strength scaling

In order to compare the strength results of brittle materials from various testing methods or use the data for design purposes, it is essential to know the effective volume (Veff) or surface (Seff) for every loading scenario. For the Ball-on-Three-Balls-test (B3B), Veff and Seff have to be determined and investigated through Finite-Element-Analysis due to the lack of an accurate analytical description of the stress field. Through this work, the effective volume and surface of the B3B-test are made available as tabulated data for a wide range of specimen geometries and materials, along with the tools to utilize the data. A fitting model for the dependency of Veff and Seff on the Weibull-modulus for any given specimen geometry is provided. The influence of load-dependent non-linear effects on Veff and Seff is discussed. Finally, the necessity of Veff and Seff for statistical strength analysis is demonstrated through a practical example.

Correlation analysis of the gradation design parameters and mechanical performance of semi-flexible pavement

Semi-flexible pavement (SFP) has been widely used for ant-rutting performance and resistance in heavy load conditions. The asphalt mixture skeleton was the central part in the complex-skeleton material system. However, few studies have been made on the connection of asphalt mixture skeleton composition and performance on semi-flexible pavement material. Therefore, the relationship between the skeleton gradation volumetric characteristic and mechanical properties of semi-flexible pavement material was investigated. Eight gradations with different coarse aggregate contents were constituted. The mechanical performances were conducted to establish the relationship between primary gradation performance. The result shows that the porosity of the asphalt matrix and Cantabro abrasion test are related to the composition of gradation. The tensile performance, shear characteristics, and compressive strength were affected by the voids filled asphalt (VFA), porosity, and fine aggregate to asphalt ratio (FB), respectively. The Burgers model accurately reflected the creep curves of the semi-flexible pavement material specimens. The creep modulus was related to the VFA, porosity, and effective asphalt content (Pbe). The gradation design parameters of open-gradation asphalt mixtures for semi-flexible pavement materials could be obtained based on the target performance. It is possible to reduce material testing times based on the correlation analysis effectively.