Small Geometry Research Articles

Glacier thickness modelling and monitoring with geophysical data constraints: A case study on the Indren Glacier (NW Italy)

AbstractThe ongoing global temperature increase has accelerated the mass loss of glaciers worldwide, with Italian alpine glaciers being particularly vulnerable due to their small size, complex geometries and exposition that implies a fast reaction to thermal and hydrological modifications. In such a frame, the Indren Glacier (Aosta Valley, north‐western Italian Alps) provides a valid test site to check the thickness evolution over the last two decades (1999–2020), through an integrated approach combining historical data, on‐site geophysical measurements, remote sensing surveys, modelling and temperature analysis. Using a 2018 helicopter‐based photogrammetric survey and Ground Penetrating Radar (GPR) survey campaigns of 2020, we obtained new input data and constraints to build up an updated thickness model for the whole glacier through the Glacier Thickness Estimation algorithm (GlaTE). Ice thickness is indeed a key parameter to estimate the ice volume and use it as further input in evolutionary models forecasting future scenarios. As a part of this integrated approach, we also analysed remote sensing and temperature data, finding a major modification in the glacier conditions over the last decade. Further comparing these results with previous studies, we identified a significant decrease in ice thickness, and we confirmed the presence of an over‐deepening in the glacier central widest part. This integrated methodology enhances our understanding of glacier dynamics and improves predictions of future changes, offering crucial insights for managing water resources and mitigating natural hazards in the alpine region.

Investigation of surface roughness and burr formation in micromilling processes laser polishing on selective laser melted Ti6Al4V

This study aims to increase the microhardness of Ti-6Al-4 V produced by laser polishing (LP) with selective laser melting (SLM), to make micromachinability with optimum parameters and to minimize surface roughness. LP process has started to attract great industrial interest today due to the significant increase in surface quality. In addition, the processing of small geometry channels, requiring precision and high surface quality, further increases the importance of micromilling. In this experimental study, the surface morphology, microhardness and micromachinability of Ti-6Al-4 V material produced by SLM were investigated before and after LP. The aim is to investigate the increase in microhardness, surface roughness, and burr amount with 3 different spindle speeds (4000-6000-8000), 4 different feed rates (2-4-6-9), and 2 different depths of cut used as micromilling parameters. When the SLM material was compared to the LP material, the hardness value increased by approximately 27%. It was observed that there was a 400% improvement in surface roughness values (Sa). When viewed with three-dimensional surface topography, it is seen that the cutting marks are more prominent in the material made with LP. Surface roughness values are inversely proportional to cutting speed and directly proportional to feed rate. While materials with high hardness should have lower surface quality in machined areas, Sa values are lower in LP areas. In addition, the difference between the surface roughness values is maximum for both SLM and LP material at the same depths of cut. These findings are aimed to determine the machinability parameters during the manufacturing of materials used especially in the aviation, defense, medical, and automotive industries.

TMOD-09. NEWLY DESIGNED TUMOR TREATING FIELDS (TTFIELDS) ARRAYS FOR THE MOUSE HEAD DEMONSTRATE EFFICACY FOR TREATMENT OF GLIOBLASTOMA

Abstract Tumor Treating Fields (TTFields) therapy is a cancer treatment modality based on continuous, non-invasive delivery of electric fields. TTFields therapy is approved for treatment of glioblastoma (GBM), delivered to the patient’s brain by two array pairs placed on the scalp. Further research in animals to expand the knowledge regarding TTFields treatment of GBM is limited, as this is mainly performed in mouse models and arrays for application of TTFields to the mouse head are lacking. The small dimensions and specific geometries of the mouse head make the development of such arrays challenging. The aim of this study was to design arrays that will allow efficient and stable delivery of TTFields to the mouse head. To overcome the small head size, we developed a layout with two arrays situated on the head of the mouse, each divided into two smaller disks, and positioned opposite two arrays on the torso. We identified a thin and transparent adhesive tape (facilitating correct array positioning) with good tackiness and easy removal (without leaving residual adhesive on the skin). The arrays met the minimum treatment requirements: current ≥ 50 mA, usage ≥ 75%, field intensity ≥ 1 V/cm RMS. We then conducted an efficacy study with the new arrays, using GL-261 GBM cells intracranially injected into C57BL/6 mice. Treatment with sham-heat (control) or TTFields was initiated 11 days following tumor inoculation and maintained continuously for 12 days. Efficacy was measured via magnetic resonance imaging (MRI) of tumor volume, showing a decrease of 31% at treatment end in TTFields-treated mice versus the control. Overall, the new arrays are flexible, strongly adherent, deliver TTFields at a sufficient intensity, and showed efficacy for treating GBM in mice.

Source-detector trajectory optimization for FOV extension in dental CBCT imaging

In dental imaging, Cone Beam Computed Tomography (CBCT) is a widely used imaging modality for diagnosis and treatment planning. Small dental scanning units are the most popular due to their cost-effectiveness. However, these small systems have the limitation of a small field of view (FOV) as the source and detector move at a limited angle in a circular path. This often limits the FOV size. In this study, we addressed this issue by modifying the source-detector trajectory of the small dental device. The main goal of this study was to extend the FOV algorithmically by acquiring projection data with optimal projection angulation and isocenter location rather than upgrading any physical parts of the device. A novel algorithm to implement a Volume of Interest (VOI) guided trajectory is developed in this study based on the small dental imaging device's geometry. In addition, this algorithm is fused with a previously developed off-axis scanning method which uses an elliptical trajectory, to compensate for the existing constraints and to further extend the FOV. A comparison with standard circular trajectory is performed. The FOV of such a standard trajectory is a circle of 11 cm diameter in the axial plane. The proposed novel trajectory extends the FOV significantly and a maximum FOV of 19.5 cm is achieved with the Structural Similarity Index Measure (SSIM) score ranging between (≈98-99%) in different VOIs. The study results indicate that the proposed source-detector trajectory can extend dental imaging FOV and increase imaging performance, which ultimately results in more precise diagnosis and enhanced patient outcomes.

Polyvinyl alcohol assisted citrate based reduction of gold(III) ions: Theoretical design and experimental study on green synthesis of spherical and biocompatible gold nanoparticles

In this study, we demonstrate the synthesis of small gold nanoparticles (typically 8–10 nm) through a green synthesis approach. This method involves utilizing chloroauric acid as the gold precursor, trisodium citrate as a mild reducing and co-capping agent, and polyvinyl alcohol (PVA), as a co-capping and shape-directing agent. This novel synthesis method stands alone as a protocol that involves just mixing the reagents at room temperature and allowing the reaction to proceed at ambient temperature without any disturbance. In the absence of PVA, spherical particles are not formed and the reaction mixture slowly turns black followed by precipitation.The synthesis process was meticulously tracked using time-resolved monitoring of the growth of the localized surface plasmon resonance (LSPR) by UV-vis spectroscopy and transmission electron microscopy. The as-prepared colloidal gold solution was bright red, attributed to the small size (≤10 nm) and spherical geometry of nanoparticles. This colloidal solution could be stored indefinitely at room temperature without precipitation or a change in its absorption profile. The nanoparticles remained stable in adverse conditions such as 100 mM NaCl solution, 1 × PBS and cell culture medium. Additionally, they could be easily loaded with drugs like doxorubicin by adsorption. The particles were thoroughly characterized using a range of techniques, including UV-vis spectroscopy, attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), high-resolution transmission electron microscopy (HRTEM), hyperspectral-enhanced dark field microscopy (HEDFM), dynamic light scattering (DLS), and X-ray photoelectron spectroscopy (XPS). Cell viability tests conducted on 2D cell lines and 3D spheroids revealed negligible toxicity even at high concentrations. Furthermore, we demonstrated that an advanced version of conventional diffusion-limited aggregation (DLA) schemes, which allows individual clusters to move freely within a domain to form larger aggregates, can effectively replicate the intricate interactions between chloroauric acid, trisodium citrate, and PVA, the agents involved in the synthesis of gold nanoparticles.

Optimal Layout of Modular Systems by Geometric Perturbations

In this study, we investigate the potential of integrating geometric perturbations into the design process to optimise modular systems such as floor coverings, façade claddings, and masonry walls. By allowing small geometry adjustments of the initial design, we achieve significant reductions in material waste or labour requirements, leading to cost-saving and environmental benefits without compromising the design concept. We compared our approach to traditional methods, where the layout of the modular system is determined after the geometry of the design is finalised. To illustrate our method, we present case studies for two- and three-dimensional modular designs.

Computer modeling and validation testing for glenoid component rotation and optimal glenoid screw angles for reverse shoulder arthroplasty in an Asian population

PurposeGood initial fixation of glenoid component for reverse total shoulder arthroplasty (RTSA) relies on component placement and screw purchase in the scapula bone. This is especially difficult in an Asian population with small glenoid geometry. Optimal glenoid component roll angle and screw angulation to achieve the longest screws for best fixation has not been defined in the current literature.MethodsComputer 3D modelling of 133 scapulas with RTSA performed were analyzed to determine patient specific optimal glenoid roll angle (GRA) for the longest bi-cortical screws attainable. The cranial-caudal angle (CCA), anterior-posterior angle (APA) and lengths for the superior and inferior screws were measured. Validation testing using calculated average (CA) angles and rounded average (RA) angles to the nearest 5 degree were recomputed for each case to determine the bi-cortical screw lengths achievable. The CA and RA screw lengths were compared against patient specific modelling using paired-sample t-tests.ResultsAverage GRA was − 1.6°, almost perpendicular to the long axis of the glenoid and achieves an average bi-cortical screw length of 51.3 mm and 45.5 mm for the superior and inferior screws respectively. The CCA and APA were 9.1° cranial and 6.5° posterior for the superior screw and screw angulation of 11.2° caudal and 0.7° anterior for the inferior screw. Validation testing shows statistically shorter screw lengths in the CA and RA models compared to patient specific modelling (p < 0.01).ConclusionValidation testing with average angles for GRA, CCA and APA demonstrates strong patient heterogeneity and anatomical variation. Despite this, screw lengths attainable in the RA group were > 38 mm with good safety profile. Surgeons may consider the additional use of navigation-assisted, or 3D printed patient specific instrumentation to optimize baseplate and screw configuration for RTSA.

Cracking in semiconductor devices–effect of plasticity under triaxial constraint

A semiconductor device integrates dissimilar materials of small sizes and complex geometries. During fabrication, the materials are deposited at various temperatures. Both deposition and change in temperature cause stresses in the materials. Under the stresses, ductile materials may deform plastically, and brittle materials may crack. Here we focus on how plastic deformation in the ductile materials affects cracking in nearby brittle materials. We study a model structure in which a metal line is encased by a silicon substrate and a brittle oxide layer. In the triaxially constrained metal, the stresses readily exceed the yield strength of the metal. Such high stresses in the metal elevate the stresses in the oxide. The degree of triaxial constraint varies with the aspect ratio of the metal. We compute the stress in the oxide, as well as the energy release rate of an edge crack and a long channel crack. We discuss strategies to avert cracking in the oxide.

Characterization of an additively manufactured coating using an upsetting test with miniaturized cylindrical specimen

In order to reduce CO2 emissions in production industry, the combination of several manufacturing processes is coming to the fore. One example is the combination of metal additive manufacturing with the forming technology, whereby the advantages of both process technologies can be used. The process combination can be applied to produce hybrid barrel sleeves, for example. Using a laser-based directed energy deposition (DED-LB/M), a circular coating is first applied to a blank, which is then deep-drawn in a second step. The additive layer serves as a wear-resistant coating. One way to increase process understanding for this process combination is numerical simulation. An important part of setting up the simulation model is characterizing the material in terms of its mechanical behavior. In order to avoid long building times, small sample geometries are suitable for characterizing the additive material. In the context of the paper, the upsetting test is therefore carried out with miniaturized specimens, whereby not only the base material Bainidur AM but also the addition of tungsten carbide microparticles and carbon nanoparticles is investigated. The in-situ modification of the material significantly increases the yield strength, but at the same time reduces the ductility. The microhardness of the material is also increased by the addition of carbon or tungsten carbide.

A Method to Design an Efficient Airfoil for Small Wind Turbines in Low Wind Speed Conditions Using XFLR5 and CFD Simulations

Small wind turbines operating in low wind speed regions have not had any significant success. In addition, small wind speed regions occupy a large area of the world, so they represent a potential area for installing small wind turbines in the future. In this paper, a method to design an efficient airfoil for small wind turbines in low wind speed conditions using XFLR5 and CFD simulations is implemented. Because the impact of the airflow on the blade surface under low Re number conditions can change suddenly for small geometries, designing the airfoil shape to optimize the aerodynamic performance is essential. The tuning of the key geometric parameters using inversion techniques for better aerodynamic performance is presented in this study. A two-dimensional model was used to consider the airflow on the airfoil surface with differences in the angle of attack. The original S1010 airfoil was used to design a new airfoil for increasing the aerodynamic efficiency by using V6.57 XFLR5 software. Subsequently, the new VAST-EPU-S1010 airfoil model was adjusted to the maximum thickness and the maximum thickness position. It was simulated in low wind speed conditions of 4–6 m/s by a computational fluid dynamics simulation. The lift coefficient, drag coefficient, and CL/CD coefficient ratio were evaluated under the effect of the angle of attack and the maximum thickness by using the k-ε model. The simulation results show that the VAST-EPU-S1010 airfoil achieved the greatest aerodynamic efficiency at an angle of attack of 3°, a maximum thickness of 8%, and a maximum thickness position of 20.32%. The maximum value of CL/CD of the new airfoil at 6 m/s was higher than at 4 m/s by about 6.25%.

Real-time passive underwater localization using a compact acoustic sensor array

This paper proposes an underwater passive localization system that can be installed on remote platforms and can locate in real-time sound sources using a compact 4-element array. The localization system relies on both the Time Difference of Arrival (TDoA) algorithm to localize sources that are impulsive, and a low-complexity implementation of the matched field processing (MFP) algorithm for broadband continuous waves, such as propeller noise. The array is intended to be mounted on small platforms and compact geometries are investigated to optimize the localization accuracy. Figures of merit are defined to assess the accuracy and reliability of the algorithm as a function of the distance between the elements. The proposed algorithm is implemented on a System-on-Chip (SoC) which executes the algorithm on an embedded system for real-time operation. Finally, the performance is assessed in realistic ocean conditions in different environments. It is shown that the MFP provides an excellent angle estimate for broadband continuous sources, but TDoA is more reliable, particularly when the deployment is sensitive to the environment conditions.

Mycotoxins: Their presence in food and relationship with nanoparticles

Mycotoxins are toxic compounds that are produced by certain fungi species; these compounds are found in many food products and may have detrimental effects on the health of human beings and livestock. Mycotoxins spoilage in food triggers both short-term and long-term effects including upset stomachs, liver, kidney, and neurological disorders. Typically used inspection methods for determination of mycotoxins in foods are cumbersome, tedious, and can sometimes give out inaccurate results. Therefore, there is a need for improvement in the approaches used for early detection of mycotoxins and the control of mycotoxin contamination in foods. As for the fourth direction, we can pinpoint nanotechnology for the detection of mycotoxin and their prevention as a promising field of study. When manipulated for use in food, the small size, geometry and surface characteristics of nanoparticles can be used to improve the detection and elimination of mycotoxins in foods. To date, implementation of nanoparticles in food safety is rather limited; however, the potentials of the technology have been highlighted by the existing studies. For instance, some current research has ascertained that nanoparticles are capable of adsorbing mycotoxins so that these toxins are easily separated from the food products. Also, nanoparticles can also be applied for the purpose of degrading or neutralizing mycotoxin.

Quantification of membrane fluidity in bacteria using TIR-FCS

Plasma membrane fluidity is an important phenotypic feature that regulates the diffusion, function, and folding of transmembrane and membrane-associated proteins. In bacterial cells, variations in membrane fluidity are known to affect respiration, transport, and antibiotic resistance. Membrane fluidity must therefore be tightly regulated to adapt to environmental variations and stresses such as temperature fluctuations or osmotic shocks. Quantitative investigation of bacterial membrane fluidity has been, however, limited due to the lack of available tools, primarily due to the small size and membrane curvature of bacteria that preclude most conventional analysis methods used in eukaryotes. Here, we develop an assay based on total internal reflection-fluorescence correlation spectroscopy (TIR-FCS) to directly measure membrane fluidity in live bacteria via the diffusivity of fluorescent membrane markers. With simulations validated by experiments, we could determine how the small size, high curvature, and geometry of bacteria affect diffusion measurements and correct subsequent measurements for unbiased diffusion coefficient estimation. We used this assay to quantify the fluidity of the cytoplasmic membranes of the Gram-positive bacteria Bacillus subtilis (rod-shaped) and Staphylococcus aureus (coccus) at high (37°C) and low (20°C) temperatures in a steady state and in response to a cold shock, caused by a shift from high to low temperature. The steady-state fluidity was lower at 20°C than at 37°C, yet differed between B. subtilis and S. aureus at 37°C. Upon cold shock, the membrane fluidity decreased further below the steady-state fluidity at 20°C and recovered within 30 min in both bacterial species. Our minimally invasive assay opens up exciting perspectives for the study of a wide range of phenomena affecting the bacterial membrane, from disruption by chemicals or antibiotics to viral infection or change in nutrient availability.

Challenges for Leading Edge node FINFET

The primary focus of this work is to find out the challenges associated with 7nm node finFET. To enable the current generation of gadgets/instruments, foundries are going toward smaller geometries (FinFET 7nm, 5nm, etc.) for manufacturing SOC/ASIC. To support the 7nm technology node without EUV, the Layout Design Rules have been scaled quite aggressively. As a result, obtaining satisfactory performance and yield in High Volume Manufacturing (HVM) has become a difficult undertaking. The gains in terms of power, performance, and other characteristics that become available with reduced geometries are the main drivers driving this movement. Analog/mixed-signal circuits, on the other hand, do not fully achieve these gains. They get increasingly difficult to design, with higher parasitic resistance and capacitance, more layout-dependent effects, and, in certain cases, layout growth. While in terms of fabrication the challenges are in node and cost, mask making, patterning, transistor formation, BEOL, MEOL, Technology parasitic elements and process control etc. This indicate what are the challenges for design of 7nm node FinFET.

Numerical Study of Mechanical Development of Patient-Specific Mandibular Reconstruction Implant

Patient-specific mandibular reconstruction implants are a new technique to deal with ameloblastoma tumors. Although they could solve the integration problem which is attributed to the graft reconstruction approach, they may increase the risk of infection due to poor blood supply around it. Using bone grafts besides customized plates with smaller geometries would be considered as an alternative. However, they would also have possible complications like poor graft integration and plate fracture. Considering weight reduction patterns on implants would efficiently help to solve the mentioned problems. In this study, two design concepts of mandibular reconstruction implants which were different in weight reduction pattern’s location were presented. Also, a finite element assessment was performed to evaluate the mechanical performance and functionality of the implants under chewing load. Results revealed that designing patterns all over the implant geometry would lead to minimum jaw deviation and maximum Von Mises stress values around 120 MPa which is much less than Ti6Al4V yield stress. Compared to the solid design, the patterns would enhance the implant function by decreasing the deviation which would result in a function similar to the intact side. Although results showed the proper functionality of the implant clinical trials with multiyear follow-ups are still needed to investigate the detailed clinical results of this concept.

Cytoarchitectonic Analysis and 3D Maps of the Mesial Piriform Region in the Human Brain

The mesial piriform region plays a central role in olfaction. Its small size and complex geometry, however, make it a difficult target in functional neuroimaging studies, while histological maps often represent schematic drawings, which are not compatible with requirements for modern imaging. To bridge this gap, cytoarchitectonic analysis and mapping of the region was performed in serial histological sections over their full extent in 10 postmortem brains. The temporobasal areas PirTBd and PirTBv and temporal areas PirTu and PirTit were identified and analyzed. Probabilistic cytoarchitectonic maps of the piriform areas in MNI reference space and high-resolution maps of the amygdala-piriform region on the BigBrain model were calculated as part of the Julich-Brain. Differences in the cytoarchitectonic “texture” of the region were quantified based on the Gray Level Co-Occurrence Matrix. Results showed that allocortical areas were not consistently associated with the rostral Limen insulae, although it was often suggested as a landmark in neuroimaging protocols. PirTu was associated with the uncal tip. PirTit was the largest area, reaching to the temporal pole, with a “temporal” (caudal) and a “temporopolar” (rostral) part having complex neighborhood relationships. The probabilistic maps reflect interindividual variability; they are openly available via the digital EBRAINS platform to serve as an anatomical reference for studies related to olfaction.

Abstract 5808: Designing arrays for delivering tumor treating fields (TTFields) to the mouse head

Abstract Introduction: Tumor Treating Fields (TTFields) therapy is an approved treatment for glioblastoma (GBM), the most abundant malignant brain tumor. TTFields therapy is delivered to patients suffering from GBM continuously by two array pairs placed on their scalp. Since arrays for TTFields application to the mouse head are lacking, and as most GBM animal models are based on mice, in vivo studies of GBM treatment with TTFields are limited. The development of such arrays is challenging due to the small dimensions and specific geometries of the mouse head, but is needed to allow continued preclinical studies to broaden the understanding of the effects of TTFields on GBM. Methods: We tested various array layouts to identify one that will be suited to the specific geometries of the mouse head. For animal well-being, the selected array was required to minimally restrict head movement. Additionally, we investigated adhesive tapes to allow on one hand good adherence of the arrays to the skin, and on the other hand easy array removal. To examine the feasibility of treating mice with these arrays, they were applied to mice for 11 days, while recording the electric currents and the actual treatment time (from which the percent usage could be calculated). To validate that the selected array layout delivers meaningful field intensity to the desired region, we performed field measurements using a floating scope. Results: To tackle the limitation of the small head size, we developed an array layout in which only two arrays were situated on the head, while the opposing arrays were located on the mouse torso. Additionally, the arrays on the head were divided into two smaller disks. We also identified a thin and transparent adhesive tape (facilitating correct arrays positioning), that offered good tackiness and allowed easy removal without leaving residual adhesive on the skin. The arrays met the minimum treatment requirements: current ≥50 mA, usage ≥75%, field intensity ≥1 V/cm RMS. At the posterior side of the mouse head, at a location more directly underneath the arrays, field intensity was higher than at the anterior position. Conclusion: TTFields could be delivered at sufficient intensities to mice heads by utilizing specifically engineered arrays. Our newly developed arrays are flexible and strongly adhering to enable efficient electric field delivery. By allowing TTFields delivery to mice heads, we will facilitate further advancing this research field. Citation Format: Sewar Zbidat, Roni Blatt, Mariell Sellevoll, Martin Gabay, Inbar Schlachet, Shay Cahal, Shiri Davidi, Itai Tzchori, Adi Haber, Moshe Giladi, Yoram Palti. Designing arrays for delivering tumor treating fields (TTFields) to the mouse head [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5808.

Straight fiber bundles with non-uniform porosity: Shell-side hydrodynamics and mass transfer in cross flow

This study explores fully developed shell-side hydrodynamics and mass transfer past straight fiber bundles with non-uniform porosity in cross-flow. Simplified geometries made up by checkerboard arrays of alternately high and low porosity regions are considered. Simulations are performed for two domain sizes: a small geometry (26 fibers) and a large geometry (104 fibers). In the small geometry, the Darcy friction coefficient (fT) exhibits hydraulic isotropy at low transverse flow Reynolds numbers (ReT) but becomes dependent on the flow attack angle (θ) at higher ReT. In the large geometry, this dependency is observed at lower ReT. A non-uniform porosity reduces fT at almost all ReT and θ in the small geometry, with the large geometry exhibiting a more complex behavior. Regarding mass transfer, up to ReT≈1-10 (depending on θ), a non-uniform porosity leads to lower Sherwood numbers compared to regular square arrays. However, at higher ReT, it enhances mass transfer.

A finite element model for investigating the influence of keel design and position on unicompartmental knee replacement cementless tibial component fixation

ObjectivesThe cementless Oxford Unicompartmental Knee Replacement (OUKR) tibial component relies on an interference fit to achieve initial fixation. The behaviour at the implant-bone interface is not fully understood and hence modelling of implants using Finite Element (FE) software is challenging. With a goal of exploring alternative implant designs with lower fracture risk and adequate fixation, this study aims to investigate whether optimisation of FE model parameters could accurately reproduce experimental results of a pull-out test which assesses fixation. Materials and methodsFinite element models of implants with three methods of fixation (standard keel, small keel, and peg) in a bone analogue foam block were created, in which implants were modelled using an analytical rigid definition and the foam block was modelled as a homogenous linear isotropic material. The total interference and elastic slip were varied in these models and optimised by comparing simulated and experimental results of pull-out tests for two (standard and peg) implant geometries. Then the optimised interference and elastic slip were validated by comparing simulated and experimental data of a third (small keel) implant geometry. ResultsThe optimisation of parameters established an interference of 0.16 mm and an elastic slip of 0.20 mm as most suitable for modelling the experimental force–displacement plots during pull-out. This combination of parameters accurately reproduced the experimental results of the small keel geometry. The maximum pull-out forces from the FE models were consistent with experimental data for each implant design. ConclusionsThis study shows that experimental pull-out tests can be accurately modelled using adjusted interference values and non-linear friction and outlines a method for determining these parameters. This study demonstrates that complex problems in modelling implant behaviour can be addressed with relatively simple models. This can potentially lead to the development of implants with reduced risk of failure.

Preliminary evaluation of properties and performance of natural rubber (NR) latex band for microplastic capturing in seawater

Microplastic particles are emerging water-laden waste that cause a worrying concern towards the environment and humans health. Due to its small size and geometry, and uncertain surface properties, the microplastic waste capturing method in water is still evolving. To date, a number of findings report on the emergence of microplastic surface charging, especially when exposed to water environment. In this study, the natural rubber (NR) latex band was utilized to capture the microplastic waste via a surface capturing mechanism. The NR band was produced using a film casting and curing methods. The surface charging mechanism on the NR band was introduced via the usage of high amount of ZDEC accelerator and, periodic stretching and relaxation procedures. In this work, ZDEC was used as an accelerator for the rubber formulation, and surface charge booster for the NR band. The surface charge of the NR band generates electrostatic interaction with the microplastic waste in water. The polypropylene (PP) microplastic was captured via the surface attraction mechanism using the manufactured NR band. Based on FTIR analysis, the presence of PP microplastic can be quantified on the contaminated NR band surface. The NR band shows the improvement in tensile and tear properties and crosslink density, mainly due to high amount of ZDEC used. At ZDEC loading of 20 phr, the NR band recorded the highest surface potential value, and this is owing to the formation of Zn2+ complex ions on its surface. XRF analysis indicates that the increment of Zn content in the NR band with increasing ZDEC content, that suggests the formation of Zn2+ complex ions.