Plate System Research Articles

Analysis of recent African tectonic plate system kinematics based on GNSS data

Analysis of recent African tectonic plate system kinematics based on GNSS data

Stochastic Vibrations of a System of Plates Immersed in Fluid Using a Coupled Boundary Element, Finite Element, and Finite Difference Methods Approach.

The main objective of this work is to investigate the natural vibrations of a system of two thin (Kirchhoff-Love) plates surrounded by liquid in terms of the coupled Stochastic Boundary Element Method (SBEM), Stochastic Finite Element Method (SFEM), and Stochastic Finite Difference Method (SFDM) implemented using three different probabilistic approaches. The BEM, FEM, and FDM were used equally to describe plate deformation, and the BEM was applied to describe the dynamic interaction of water on a plate surface. The plate's inertial forces were expressed using a diagonal or consistent mass matrix. The inertial forces of water were described using the mass matrix, which was fully populated and derived using the theory of double-layer potential. The main aspect of this work is the simultaneous application of the BEM, FEM, and FDM to describe and model the problem of natural vibrations in a coupled problem in solid-liquid mechanics. The second very important novelty of this work is the application of the Bhattacharyya relative entropy apparatus to test the safety of such a system in terms of potential resonance. The presented concept is part of a solution to engineering problems in the field of structure and fluid dynamics and can also be successfully applied to the analysis of the dynamics of the control surfaces of ships or aircraft.

Seismic Analysis of a Multi-Storey Building with Different Types of Slabs

Earthquake plays an influential role in the analysis and design of structures. Unless the structures are designed and constructed to withstand seismic forces, failure cannot be avoided. Buildings can be made seismically sound with proper structure design, detailing and construction practice. The configuration of a building is very much important for the seismic performance of buildings. The important aspects that affect the seismic configuration of a building are overall geometry and structural system. This parameter varies in their behaviour in the flat slab, waffle slab and conventional slab. Therefore introducing different types of slabs becomes very crucial for a structural engineer when it comes to better performance of RC structure. The objective of this paper is to study the seismic behaviour of multi-storeyed buildings with different types of slab systems. The study is done by considering the varying number of stories i.e. low-rise, mid-rise and high-rise buildings. The study aims to find an effective slab system for both regular and irregular structures. The different types of slabs considered are flat plate system, flat slab with drop system and waffle slab system which is compared with the conventional slab system. Seismic assessment using response spectrum analysis is done. For low-rise to high-rise buildings, the seismic behaviour of the waffle slab is more effective.

Design of well-matched end-structure of anatomical proximal femoral locking plate based on computer-assisted imaging combined with 3D printing technology: a quality improvement study.

The extramedullary locking plate system was the common internal fixation method for hip fractures. However, common plates were poorly matched to femur, which was because they were designed based on anatomical parameters of the Western populations. Therefore, the aim was to design an end-structure of the anatomical proximal femoral locking plate that closely matched the anatomy of the Chinese population. From January 2010 to December 2021, consecutive patients aged 18 years and older who underwent a full-length computed tomography scan of the femur were included. The end-structure (male and female model) of the anatomical proximal femoral locking plate was designed based on anatomical parameters of femurs that were measured in three-dimensional space using computer-assisted virtual technology. The match degree between the end-structure and femur were evaluated. Inter-observer and intra-observer agreement for the evaluation of match degree was assessed. The matching evaluation based on a three-dimensional printing model was regarded as the gold standard to assess the reliability. A total of 1672 patients were included, with 701 men and 971 women. Significant differences were seen between male and female for all parameters of the proximal femur (all P <0.001). All match degree of end-structure was over 90%. Inter-observer and intra-observer agreement was almost perfect (all kappa value, >0.81). The sensitivity, specificity, and percentage of correct interpretation of matching evaluation in the computer-assisted virtual model was all greater than 95%. From femur reconstruction to completion of internal fixation matching, the process takes about 3min. Moreover, reconstruction, measurement, and matching were all completed in one system. The results showed that based on the larger sample of femoral anatomical parameters, a highly matching end-structure of anatomical proximal femoral locking plate for Chinese population could be designed with use of computer-assisted imaging technology.

Multi-Planar Jump Performance in Speed Skating Athletes: Investigating Interlimb Differences in an Asymmetrical Sport

Elite speed skaters are exposed to asymmetric lower limb loading consequent to the unidirectional turns inherent to the sport. This presents a unique model to study the effects of sport-specific loading on interlimb differences in mechanical muscle function. This study, therefore, examined baseline interlimb asymmetries in multi-directional jump tests in elite speed skaters using a cross-sectional design. Thereafter, participants were monitored longitudinally using the bilateral countermovement jump (CMJ) to quantify interlimb differences in mechanical muscle function throughout a competitive season. Pre-season baseline testing included a single leg lateral jump (JumpLat) and a single leg forward horizontal jump (JumpHorz) attached to a robotic linear position encoder, along with a bilateral CMJ on a dual force plate system. From baseline, CMJ monitoring was conducted throughout the 24-week competitive season. Within-limb changes in right vs left CMJ concentric impulse (CMJCon) and eccentric deceleration impulse (CMJEcc) were assessed using a linear mixed effects model. No systematic interlimb differences were found at baseline (p = 0.33–0.98) and the between-test agreement in limb dominance was poor (Kappa = −0.17–0.33). Furthermore, there were no time effects observed for interlimb differences in CMJCon (fixed effect = 0.01 N*s) and a small decrease in CMJEcc (fixed effects = −0.35 N*s, p = 0.01). These data suggest that even in a sport with asymmetrical loading, interlimb differences in mechanical output remain stable at the group level. However, changes occurring at the individual athlete level may be occurring that are meaningful for performance and injury.

Evaluation of the Effect of Spatial Resolution on Image Quality in Phosphor Plate Systems

Purpose: This study aims to investigate the effect of 4 different scanning protocols offered by the VistaScan Mini Easy scanner on image quality at different exposure times. Materials &amp;amp; Methods: Four number size-2 photostimulable phosphor plates were exposed with 5 different exposure times while keeping other parameters constant. The exposed plates were scanned without delay using 4 different scanning protocols. 10 lp/mm, 20 lp/mm, 25 lp/mm, and 40 lp/mm are offered by the VistaScan Mini Easy scanner. The mean gray value was calculated using the ImageJ program by identifying three non-overlapping regions of interest from the background and each step in the obtained images. The mean of all mean gray values determined for the background and steps on a plate was also considered the mean gray value of that plate. Results: When plate mean gray values at 0.20 s and 0.40 s were examined, a statistically significant difference was observed between the scanning protocols (p&amp;lt;0.001, p=0.001 respectively). It was determined that the plate mean gray value at 40 lp/mm in 0.20 s was lower than that of other scanning protocols. The plate mean gray value at 20 lp/mm in 0.20 s was higher than that at 25 lp/mm. It was determined that the plate mean gray value at 10 lp/mm in 0.40 s was lower than that of the other groups. Conclusion: The effect of spatial resolution on diagnostics in digital imaging per se is a subject under investigation and still not agreed upon. Therefore, more studies on spatial resolution are needed.

Breaking the Ring of Fire: How Ridge Collision, Slab Age, and Convergence Rate Narrowed and Terminated the Antarctic Continental Arc

AbstractThe geometry of the Antarctic‐Phoenix Plate system, with the Antarctic Plate forming both the overriding plate and the conjugate to the subducting oceanic plate, allows quantification of slab age and convergence rate back to the Paleocene and direct comparison with the associated magmatic arc. New Ar‐Ar data from Cape Melville (South Shetland Islands, SSI) and collated geochronology shows Antarctic arc magmatism ceased at ∼19 Ma. Since the Cretaceous, the arc front remained ∼100 km from the trench whilst its rear migrated trenchward at 6 km/Myr. South of the SSI, arc magmatism ceased ∼8–5 Myr prior to each ridge‐trench collision, whilst on the SSI (where no collision occurred) the end of arc magmatism predates the end of subduction by ∼16 Myr. Despite the narrowing and successive cessation of the arc, geochemical and dyke orientation data shows the arc remained in a consistently transitional state of compressional continental arc and extensional backarc tectonics. Numerically relating slab age, convergence rate, and slab dip to the Antarctic‐Phoenix Plate system, we conclude that the narrowing of the arc and the cessation of magmatism south of the SSI was primarily in response to the subduction of progressively younger oceanic crust, and secondarily to the decreasing convergence rate. Increased slab dip beneath the SSI migrated the final magmatism offshore. Comparable changes in the geometry and composition are observed on the Andean arc, suggesting slab age and convergence rate may affect magmatic arc geometry and composition in settings currently attributed to slab dip variation.

Does the pronator-sparing approach improve functional outcome, compared to a standard volar approach, in volar plating of distal radius fractures? A prospective, randomized controlled trial

BackgroundThis study aimed to compare functional outcomes of a volar plate osteosynthesis for distal radius fractures (DRF) performed with either a standard volar approach (SVA), which required detachment of the pronator quadratus muscle, or a pronator-sparing approach (PqSA).Materials and methodsThis prospective randomized controlled study included 106 patients scheduled for volar plate osteosyntheses. Patients were allocated to either the SVA group (n = 53) or the PqSA group (n = 53). Patients were blinded to treatment until completion of the study. The primary outcome measure was the Patient-Rated Wrist Evaluation (PRWE). Secondary outcome parameters were the Disabilities of the Arm, Shoulder, and Hand (DASH) score and the Modified Mayo Wrist Score (MMWS). Follow-up examinations were performed at 8 weeks and 3, 6, and 12 months postoperatively.ResultsOverall, 91 patients were included in the final analysis: 48 in the SVA group and 43 in the PqSA group. The two cohorts were not significantly different in demographic characteristics, including age, sex, injuries on the dominant side, type of injury, and fracture classification. We found significant differences between groups at 6 months in the mean PRWE (SVA: 12.3 ± 10.4, PqSA: 18.9 ± 14.11 points) and in the mean DASH score (SVA: 12.3 ± 11.9, PqSA: 19.3 ± 16.7 points), which favoured the SVA. We found no significant differences between groups in the MMWS or in the PRWE and DASH scores at any other time points.ConclusionsThis randomized comparative clinical trial failed to demonstrate that a volar plate osteosynthesis performed with a PqSA could improve the outcome, compared to the SVA, in patients with DRF.Level of evidenceIITrial registration Comparison of Two Volar Plating Systems for Distal Radius Fractures, ClinicalTrials.gov (NCT03474445), registered 22 March 2018, retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03474445?cond=radius&cntry=AT&draw=2&rank=1

Impact of the Anatomical Accelerometer Placement on Vertical Jump Performance Characteristics.

With rapid technological development over recent years, the use of wearable athlete monitoring devices has substantially gained popularity. Thus, the purpose of the present study was to examine the impact of the anatomical placement of an accelerometer on biomechanical characteristics of countermovement vertical jump with and without an arm swing when compared to the force plate as a criterion measure. Seventeen recreationally active individuals (ten males and seven females) volunteered to participate in the present study. Four identical accelerometers sampling at 100 Hz were placed at the following anatomical locations: upper-back (UB), chest (CH), abdomen (AB), and hip (HP). While standing on a uni-axial force plate system sampling at 1000 Hz, each participant completed three non-sequential maximal countermovement vertical jumps with and without an arm swing. All devices recorded the data simultaneously. The following variables of interest were obtained from ground reaction force curves: peak concentric force (PCF), peak landing force (PLF), and vertical jump height (VJH). The findings of the present study reveal that the most appropriate anatomical locations to place the accelerometer device when attempting to estimate PCF, PLF, and VJH during a countermovement vertical jump with no arm swing are CH, AB, and UB, and during a countermovement vertical jump with an arm swing are UB, HP, and UB, respectively. Overall, these findings may help strength and conditioning professionals and sports scientists to select appropriate anatomical locations when using innovative accelerometer technology to monitor vertical jump performance characteristics.

Translucency and Radiopacity of Dental Resin Composites - Is There a Direct Relation?

The purpose of this study was to correlate the translucency degree of varying resin composites with their radiopacity. Twenty-four resin composites (conventional or bulk-fill) of various shades and opacities were selected from the following manufacturers: 3M ESPE (nanofilled), Ivoclar (nanohybrid), and FGM (microhybrid). Resin composite samples (n=5) were prepared (5-mm diameter × 1.5-mm thickness) for comparison using prepared samples of human dentin and enamel as controls. The translucency of each sample was measured using the translucent parameter (TP) method with a digital spectrophotometer (Vita Easyshade) and CIEL*a*b* color system over white and black backgrounds. The samples were also x-rayed using a photostimulable phosphor plate system for measurement of their radiopacity (in mmAl). All data were analyzed using one-way ANOVA and Student-Newman-Keuls (α=0.05); data for TP and radiopacity were correlated using the Spearman correlation test. Overall, the translucent shades and bulk-fill resin composites showed greater translucency than the other resins. While "body" and "enamel" shades demonstrated intermediate translucency to dentin and enamel, the "dentin" shades were more standardized, showing similar translucency to human dentin. All tested resin composites showed similar or greater radiopacity to human enamel, except the Empress Direct (Ivoclar) resin with Trans Opal shade, which was not radiopaque. Dentin and enamel showed radiopacity similar to 1 and 2 mmAl (millimeters of aluminum), respectively. The resin composites investigated in this study differed regarding their translucency degree and radiopacity level, without any positive relationship between the two properties.

Decay of solution for a 2D irrotational Mindlin–Timoshenko plate system

Decay of solution for a 2D irrotational Mindlin–Timoshenko plate system

A machine-learning-based model for seismic performance assessment of interior slab-column connections

Slab-column connections are the most critical components in flat plate systems under seismic actions due to their brittle failure mode. Finite element analysis (FEA) can be adopted as an extension of experimental testing to potentially lead to the development of modern design codes by providing significant information on the punching shear failure process of connections. However, the available concrete constitutive models in FEA packages fail in simulating the hysteretic response of the connections under cyclic loads. Moreover, it is shown that the available design code recommendations and empirical models are not accurate tools for assessing the seismic performance of these connections (e.g., unbalanced moment and/or drift capacity). In an effort to overcome these limitations, a dataset of previously tested experiments is compiled to predict the ultimate load and drift of the connections using the multi-variate non-linear regression model. Additionally, there is a need to develop a new constitutive material model for seismic performance assessment of the connections to capture the complete hysteretic response of the connection using numerical FEA. Consequently, a deep neural network is trained over the accumulated dataset and integrated into the OpenSees source code to determine the seismic performance of the connections. For data augmentation, a generative neural network model of autoencoders known as Generative Adversarial Networks (GANs) is constructed to generate synthetic data. The proposed material model is found to have significantly improved precision in capturing the hysteretic response of flat plates. The developed models showed higher accuracy than the design code estimations and empirical models.

Free and forced vibrations of an elastically interconnected annular plates system

Free and forced vibrations of an elastically interconnected annular plates system

Comparison of Laser-Sintered and Milled Patient-Specific Reconstruction Plates for Complications and Outcomes in Mandibular Defects-Comparative Analysis of a Single-Center Cohort.

CAD/CAM-manufactured implants are increasingly becoming the standard in current therapy. The question of whether the manufacturing-related rougher surface of selective laser fusion plates compared to milled, smoother reconstruction plates leads to increased postoperative complications such as infections, plate exposure, and fistulas has not yet been determined. A retrospective analysis of 98 patients who underwent surgical treatment with either a selective laser fusion plate or a milled reconstruction plate at our hospital was performed. The only significant predictors of the revision risk were the operation time and use of antiresorptive medication. In the KLS Martin® group, the risk of revision decreased by approximately 20% for each additional hour by which the operation time was increased (OR = 0.81). In the Depuy Synthes® group, the risk of revision increased by approximately 11% with each additional hour of operative time (OR = 0.81 × 1.37 = 1.11). Both groups showed no significant differences in the number of necessary revision surgeries as well as inpatient complications. In summary, we can say that the assumption that additively manufactured reconstruction plates have a rougher surface due to selective laser melting and thus make plaque accumulation and revisions more likely has not been confirmed. Overall, it seems imperative to select further studies regarding the clinical outcome depending on the selected plate system.

Numerical study on thermal behaviors of parallel plate systems for sensible thermal energy storage with heat loss

A numerical study on thermal energy storage systems with parallel plates to collect sensible heat is conducted with porous and direct model approaches. The simulations in a two-dimensional domain are performed with COMSOL Multiphysics commercial software. For the equivalent porous medium, the permeability and effective thermal conductivity as well as the specific area, and interfacial convective coefficient are numerically evaluated, considering a thermally and hydrodynamically fully developed flow. A stack of parallel plates is the system with assigned length and height, and the external heat losses effect is considered. The analysis allows to evaluate an optimized configuration as Channels Per Length (CPL) by means of a balance in the channels between pressure drop and heat transfer. Moreover, the effect of CPL values and heat loss from the parallel plate system is estimated in terms of charging time and heating capacity. The results exhibit that as the CPL increases, the time required for the charging process decreases while heat accumulation inside the system increases significantly. In fact, at the highest CPL, charging time is 2.7 times faster and the amount of heat accumulation is approximately 20% higher in adiabatic case. It is illustrated that the amount of heat accumulation inside the system varies considerably for different heat loss values. Ultimately, this study shows that porous model is more practical and accurate to be used for higher CPL cases.

A PROTOCOL TO EVALUATE AND VALIDATE IMPLANT INTERNAL FORCES AND MOMENTS

Implant manufacturers develop new products to improve existing fracture fixation methods or to approach new fracture challenges. New implants are commonly tested and approved with respect to their corresponding predecessor products, because the knowledge about the internal forces and moments acting on implants in the human body is unclear. The aim of this study was to evaluate and validate implant internal forces and moments of a complex physiological loading case and translate this to a standard medical device approval test.A finite elements model for a transverse femur shaft fracture (AO/OTA type 32-B2) treated with a locked plate system (AxSOS 3 Ti Waisted Compression Plate Broad, Stryker, Kalamazoo, USA) was developed and experimentally validated. The fractured construct was physiologically loaded by resulting forces on the hip joint from previously measured in-vivo loading experiments (Bergmann et. al). The forces were reduced to a level where the material response in the construct remained linear elastic. Resulting forces, moments and stresses in the implant of the fractured model were analysed and compared to the manufacturers’ approval data.The FE-model accurately predicted the behaviour of the whole construct and the micro motion of the working length of the osteosynthesis. The resulting moment reaction in the working length was 24 Nm at a load of 400 N on the hip. The maximum principle strains on the locking plate were predicted well and did not exceed 1 %.In this study we presented a protocol by the example of locked plated femur shaft fracture to calculate and validate implant internal loading using finite element analysis of a complex loading. This might be a first step to move the basis of development of new implants from experience from previous products to calculation of mechanical behaviour of the implants and therefore, promote further optimization of the implants’ design.

Efficiency of shear studs manufactured from threaded bars on the punching behavior of flat slabs

Punching resistance in flat slab systems in reinforced concrete structures is often provided with drop panels or shear reinforcement around columns. Shear studs are effectively used in these structures as shear reinforcement. However, factory-made shear studs may not be available in all locations and small quantities for small projects. Therefore, cheap shear studs that can be manufactured from widely available materials in small quantities can be very useful in certain cases. In this study, shear studs manufactured from threaded bars, widely available in hardware stores, are used for providing punching resistance to flat slabs. Stud heads were formed with T-section nuts. Four slab specimens, two with shear studs and two without, were cast and tested under concentrated loads at their mid-point. The slabs had 2150×2150×150 mm dimensions and they were cast with two different longitudinal reinforcement ratios. Test results showed that manufactured shear studs significantly increased the load and deformation capacities of the slabs. Slabs with shear studs were able to show up to three times higher bending deformations and they were able to sustain up to 50% higher loads. The study has shown that these studs can be effectively used for punching strengthening purposes in flat plate systems or in other cases where punching resistance is needed.

Hinged Roof Reconstruction of Anterior Iliac Crest after Harvesting Bicortical Strut Graft for Anterior Cervical Fusion.

The strut iliac bone graft has been widely used to achieve fusion in various anterior cervical spinal surgeries but some complications often remain, such as pain and gross deformity. Considering these, we designed a new technique to restore the iliac ridge, using the outmost part of the iliac crest. We aim to assess the efficacy of our new restoration technique of the iliac ridge after harvesting strut bone graft for anterior cervical fusion. The clinical and radiological outcomes of our hinged roof method were evaluated. A retrospective review was conducted of 29 patients who underwent hinged roof reconstruction of the iliac ridge after harvesting a bicortical strut bone graft for anterior cervical fusion using a cervical plate system. The clinical outcome for pain and gross appearance and radiological results were evaluated. Three months after the surgery, pain at the donor site became minimal or absent in all cases. At 1 year follow-up, no patient had reported pain and palpable discomfort, such as step-off on the donor site. Final X-ray and follow-up computed tomography revealed a bony union of the reconstructed iliac ridge to both margins. By showing good clinical and radiological outcomes, the authors' hinged roof reconstruction of the iliac crest after harvesting strut bone graft seemed to be a simple and effective technique that can reduce complications, such as pain and deformity on the donor iliac crest.

Influence of Element Lead (Pb) Content in Tin Plating on Tin Whisker Initiation/Growth

The implementation of the Restriction of Hazardous Substances (RoHS) European Union (EU) Directive in 2005 resulted in the introduction of pure tin as an acceptable surface finish for printed circuit boards and component terminations. A drawback of pure tin surface finishes is the potential to form tin whiskers. Tin whiskers are a metallurgical phenomenon that is associated with tin rich/pure tin materials and has been a topic of intense industry interest. The acceptance and usage of pure tin by the electronics industry component fabricators is understandable as the pure tin surface finishes are inexpensive, are simple plating systems to operate and have reasonable solderability characteristics. However, high performance/harsh environment electronics typically have product life cycles that are measured in decades and therefore are much more susceptible to the potential long term threat of tin whiskers. The GEIA-STD-0005-2 “Standard for Mitigating the Effects of Tin Whiskers in Aerospace and High Performance Electronic Systems” established the definition of the term “Pb-free tin” as : “Pb-free Tin is defined to be pure tin or any tin alloy with &lt;3% lead (Pb) content by weight. A functional definition of “pure tin” was necessary so that the electronics industry could establish tin whisker risk protocols against a known acceptable target value in terms of soldering materials and processes. An investigation was conducted to determine the influence of 1% - 5% elemental lead (Pb) content in tin plating on tin whisker initiation and growth. The investigation results were used in the revision of the GEIA-STD-0005-2 “Standard for Mitigating the Effects of Tin Whiskers in Aerospace and High Performance Electronic Systems” specification technical discussions.

Clinical Efficacy Analysis of the New PRUNUS Spine Plate System for Anterior Cervical Spine Surgery

Although the role of anterior cervical titanium plate system in stabilizing the spine sequence and promoting bone graft fusion has been widely recognized, more and more attention has been paid to the design of the plate itself and the complications caused by it. In order to solve the problems of poor stability of internal fixation, plate displacement and screw looseness, we designed the new PRUNUS spine plate system. Hence, the present study was conducted to describe observe and evaluate the clinical efficacy of a new type of three-leaf reinforced cervical anterior screw plate system (PRUNUS nailing system) developed for anterior cervical surgery. A retrospective analysis of 56 patients from June 2018 to October 2019 was used. Twenty-seven patients with cervical spine disease treated with new PRUNUS nail plate internal fixation were selected as the observation group, and 29 patients with cervical spine disease treated with conventional cervical anterior screw fixation were selected as the control group. Postoperative follow-up was performed. Cervical stability, internal fixation position and bone graft fusion were evaluated according to imaging data. The operative time, intraoperative blood loss, cervical Cobb angle, pain visual analogue scale (VAS), and Japanese orthopaedic association (JOA) were compared between the two groups. Spinal function scores and neurological improvement rates were used to evaluate the clinical efficacy of the new PRUNUS spine plate. The patients were followed up for 5-18months, with an average of 7.33months. The average operative time of the observation group was 98.4 ± 9.2 min, and the mean intraoperative blood loss was 65.3 ± 10.6ml, which were significant different from the control group's 109.7 ± 9.4 minutes (P < 0.05), 72.9 ± 15.6 ml (P < 0.05). Comparison between the two groups in postoperative and final follow-up of cervical Cobb angle, JOA score and improvement rate, VAS score and preoperative comparison showed no significant differences (P> 0.05). The new PRUNUS spine plate system can be applied to the anterior cervical spine surgery, and its clinical efficacy was similar to the traditional cervical anterior plate. But PRUNUS simplified the operation process, especially suitable for the surgical treatment of anterior cervical revision and osteoporosis patients.