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Temporary metal implants, made from materials like titanium (Ti) or stainless steel, can cause metabolic issues, raise toxicity levels within the body, and negatively impact the patient's long-term health. This necessitates a subsequent operation to extract these implants once the healing process is complete or when they are outgrown by the patient. In contrast, medical devices fabricated from absorbable alloys have the advantage of being biodegradable, allowing them to be naturally absorbed by the body once they have fulfilled their role in facilitating tissue healing. Among the various absorbable alloy systems studied, magnesium (Mg) alloys stand out due to their biocompatibility, mechanical properties, and corrosion behavior. The existing literature on absorbable Mg alloys highlights the effectiveness of silicon (Si) and zinc (Zn) additions in improving mechanical properties and controlling corrosion susceptibility; however, there is a lack of comprehensive quantitative morphological analysis of the intermetallic phases within these alloy systems. The quantification of the complex morphology of intermetallic particles is a challenging task and has significant implications for the micromechanical properties of the alloys. This study, therefore, aims to introduce a robust set of morphometric parameters for evaluating the morphology of intermetallic phases within two as-cast Mg alloys with Si and Zn additions. X-ray Computed Tomography (XCT) was used to capture the 3D tomographic data of the alloys, and a novel pair of morphological parameters (ratio of convex hull to particle volume and convex hull sphericity) was applied to the 3D tomographic data to assess the MgZn phase formed in the two alloys. In addition to the impact of composition, the effect of solidification rate on the morphological parameters was also studied. Furthermore, Scanning Electron Microscopy (SEM) and Energy-Dispersive Spectroscopy (EDS) were employed to gather detailed 2D microstructural and compositional information on the intermetallics. The comprehensive characterization reveals that the morphological complexity and size distribution of the MgZn phase are influenced by both compositional changes and the solidification rate. However, the change in MgZn intermetallic particle morphology with size was found to follow a predictable trend, which was relatively agnostic of the chosen casting conditions. [ABSTRACT FROM AUTHOR]

The microstructural characterization of lunar agglutinate samples serves many essential purposes in lunar science and cosmochemistry, from understanding the formation process of lunar regolith to preparing for human activity on the Moon. In this study, an advanced correlative characterization methodology was employed to examine the microstructure of a lunar agglutinate particle retrieved from the Apollo 11 mission. The multimodal characterization efforts were centered around 3‐D x‐ray computed tomography (XCT) and were complemented by 2‐D techniques, including scanning electron microscopy and energy‐dispersive x‐ray spectroscopy. The nondestructive nature of the XCT allowed us to preserve the lunar dust particles, while its 3‐D nature allowed us to extract meaningful microstructural information inaccessible via traditional 2‐D characterization techniques. The multimodal correlative analysis further allowed us to identify the compositional and microstructural features of the agglutinate. These observations were linked to the formation process of the agglutinate to inform a hypothesis on the dynamic formation sequence of lunar regolith. [ABSTRACT FROM AUTHOR]

When penetrometers or probes are pushed into sand, complex displacement fields, strain fields, and shear band patterns develop. Deep and shallow penetration processes in sands generate substantially different patterns. This paper reports the results of penetration experiments performed in dense air-pluviated sand samples prepared in a half-cylindrical calibration chamber equipped with observation windows that allow the collection of images of the sand during penetration. Both a cone penetrometer (diameter d=38 mm) and a model footing (width B=90 mm) are used in the penetration experiments. Incremental displacement and strain fields in the soil domain are obtained by analysis of the collected images using digital image correlation (DIC) and continuum mechanics. The zero-extension line concept is used to study shear strain localization, and a method is proposed to automatically obtain the orientation of shear band patterns from the incremental strain fields. For the model footing, the strain fields are found to localize not only near the footing but also away from it, depending on the level of penetration. The shear bands develop in a traditional wedge shape below the model footing and in a fan shape on either side of it. In contrast, for the cone penetrometer, the strain fields localize more intensely near the penetrometer tip. The shear bands develop along the inclined face and near the shoulder of the penetrometer. [ABSTRACT FROM AUTHOR]

Had the pile been driven only to a depth of HT ht , the total pile capacity would have been insufficient. The values reported in Table 5 in the original paper were obtained by taking the ratio of the HT ht (computed using CPT-based pile design methods assuming HT ht ) to the HT ht . The values reported in Table 4 in the original paper were obtained by taking the ratio of the HT ht , computed using the CPT-based pile design methods, to the HT ht ). The objective was to highlight that the CPT-based design methods severely overestimate the HT ht . [Extracted from the article]

A full-scale, double-wall, open-ended pipe pile with a diameter, B = 660 mm was densely instrumented with a combination of electrical-resistance and vibrating-wire strain gauges. The test pile was driven into a gravelly sand soil profile to a depth of 30·48 m and then statically and dynamically load tested. The double-wall instrumentation allows independent measurements of the outer shaft, inner shaft (plug) and annulus resistances during a static load test. The residual loads locked in the pile after driving were measured and considered in the correction of the resistance components. The load–settlement curve, load transfer curves and the profile of the unit limit shaft resistance were obtained from the static load test measurements. Two cone penetration test-based methods were used to estimate the resistance of the test pile, which was compared with that obtained from the static load test. Both methods provide good estimates for the unit shaft resistance in sandy layers with low gravel content (<20%), but significantly overestimate the unit shaft resistance mobilised in soil with high gravel content (>30%). The estimated base resistances by both methods match well that measured in the static load test. [ABSTRACT FROM AUTHOR]

Slow-maintained static load tests were performed on closed-ended and open-ended steel pipe piles driven side by side in a gravelly sand soil profile. The site investigation consisted of multiple cone penetration tests (CPTs) and standard penetration tests (SPTs), as well as laboratory tests on soil samples collected at various depths from the test site to determine basic soil properties. The test piles were densely instrumented with a combination of electrical-resistance and vibrating-wire strain gauges. The open-ended test pile was a specially fabricated double-wall, fully-instrumented pile, allowing for separation of the measurements of the inner and outer shaft resistances. Detailed comparison of the load test results, in terms of driving resistance, load response and profiles of unit shaft and base resistances for the two test piles, is presented and discussed. The applicability of three CPT-based pile design methods is assessed through a layer-by-layer comparison of the estimated resistances with those measured in the static load tests. [ABSTRACT FROM AUTHOR]

Coffee is one of the most widely consumed drinks in the world. It is made from roasted coffee beans and depending on the roasting level, different flavors can be extracted from the beans. However, little is known about the evolution of the internal microstructure of the coffee bean over the roasting process. This study uses X-ray Computed Tomography (XCT) and image analysis to examine the evolution of the microstructure of Coffea arabica beans during roasting. Beans sourced from Brazil, Colombia, and Ethiopia, were tracked individually throughout the roasting process. The 3D Tomography data, captured at different roasting levels, revealed detailed, time-resolved information about porosity, pore size distribution, and cracking within different regions of the beans. Results showed a significant increase in porosity and pore size from green-bean to dark-roast state, but the increase rate wasn't linearly dependent on roasting time. Furthermore, beans from different regions showed varied spatial heterogeneity in porosity and cracking. The effects of starting green bean microstructure, as influenced by growth environment, on the subsequent structural evolution are discussed. • X-ray computed microtomography was used to capture the evolution of microstructure of coffee beans with roasting. • Individual coffee beans from three different coffee-growing regions around the world (Ethiopia, Colombia, and Brazil) were studied. • Porosity and pore sizes were tracked as a function of roasting levels and their spatial heterogeneity was quantified. • Impact of the initial microstructure of the green bean on how pores develop at different roast levels was investigated. [ABSTRACT FROM AUTHOR]

This paper presents the results of laboratory tests performed to study the effect of compaction properties on the development of matric suction in four different soils (three soils were classified as silty clay and one was classified as silty sand). The soils were compacted at the optimum water content (OWC) and wet and dry of optimum according to the standard Proctor procedure (ASTM D698-12). For each sample, matric suction measurements were made using the filter paper technique. When the silty clay soils were compacted at a water content less than the OWC, a significant increase in matric suction was observed. For all the soils tested, matric suction values were very low when the compaction water contents were greater than the OWC. Plots of matric suction vs. compaction water content [ranging from (OWC-2%) to OWC] were developed for the compacted silty clays. The test results indicate that there is a direct relationship between the compaction properties (i.e. compacted dry unit weight and water content) and the matric suction values retained in compacted silty clays. Preliminary relationships were proposed between the matric suction of compacted silty clays and water content based on the data collected in this paper. [ABSTRACT FROM AUTHOR]

The Dynamic Cone Penetrometer (DCP) is a device that is used in the construction industry for the assessment of in situ soil compaction quality. Over the past few decades, numerous correlations have been developed between the DCP test results and soil strength and stiffness parameters. This paper proposes a comprehensive set of criteria and recommendations for quality control (QC) of compacted subgrade that take into account the inherent statistical variability of DCP test results. For the development of the QC criteria, a new statistical methodology is used to extract representative test values from the raw field DCP test data. In order to use the proposed QC criteria, soils are first classified into two broad categories (fine-grained and coarse-grained) depending on their fabric and response to compaction efforts. Test results indicate that (i) for fine-grained soils, the DCP test values have good correlation with the plasticity index (PI), which is indicative of the type and amount of clay content of the soil and (ii) for coarse-grained soils, the DCP test values have good correlation with the optimum water content of the soil, which is directly related to its in situ density. DCP blow count correlation equations are presented for both soil categories. Recommendations for field DCP testing and data analysis are also provided to highlight the significance of the statistical distribution of the DCP test results in QC testing of compacted subgrade. [ABSTRACT FROM AUTHOR]

An empirical expression linking the slope λ of the normal compression line (NCL) for unsaturated soils to the effective degree of saturation S e is studied in this technical note. The parameters in this empirical expression are intrinsic soil parameter α , the slope of the normal compression line (NCL) at full saturation, λ 100% , and the slope of the normal compression line at the driest state achievable by a soil, λ d (a state at which only adsorbed water remains in the pores). The determination of λ at any other level of saturation usually requires a considerable amount of test data. This technical note explores the relationship between regression parameter α and the particle size, quantified by the D 10 of the soil, based on test data for five different soils taken from the literature. A regression equation is developed that relates α to D 10 . Based on the proposed regression equation, the slope of the normal compression line for unsaturated fine-grained soils at any degree of saturation can be estimated when the test data are limited. [ABSTRACT FROM AUTHOR]