Small Opening Research Articles

The Influence of Shear Connector Numbers on The Flexural Characteristics of Composite Geopolymer Reinforced Concrete Beams With Small Transverse Web Openings

Geopolymer concrete is a sustainable alternative to conventional Portland cement-based concrete, utilizes industrial by-products like fly ash and slag. Renowned for its reduced carbon footprint and exceptional durability, geopolymer concrete is gaining global recognition in eco-friendly construction practices. Steel composite reinforced geopolymer concrete beams combine the strength of steel with the sustainability of geopolymer concrete, offering a sturdy structural solution. This collaborative approach results in a composite material with excellent crack resistance and durability, harnessing the advantageous properties of both steel and geopolymer concrete. These beams present a promising option in construction by striking a balance between structural performance and environmental considerations through the incorporation of geopolymer technology. The focus of the current study is to investigate the impact of steel connectors on the flexural behavior of composite reinforced geopolymer concrete beams that have transverse web opening through experimental methods. The experimental program involves casting four geopolymer beams, with one being a traditional geopolymer-reinforced concrete beam (Control). The remaining three specimens are composite reinforced geopolymer concrete beams, each featuring a bottom 5 mm steel plate with six, twelve, and eighteen connectors near each support. The beams share common dimensions, with a total length of 1600mm, a height of 250mm, and a width of 180mm. The results showed that increasing the number of connectors near supports increased the resulted flexural behavior of beams. Such connectors increased the first crack load from 6.67% to 42.22% while the service load increased from 16.22% to 36.20%. the load carrying capacity was also increased from 12.00% to 24.80%. Finally, the mode of failure was moved from traditional tension failure to concrete crushing.

Quantitative Easing, Bond Risk Premia and the Exchange Rate in a Small Open Economy

We assess the impact of large-scale asset purchases, commonly known as quantitative easing (QE), conducted by Sveriges Riksbank and the European Central Bank (ECB) on bond risk premia in the Swedish government bond market. Using a novel arbitrage-free dynamic term structure model of nominal and real bond prices that accounts for bond-specific safety premia, we find that Sveriges Riksbank’s bond purchases raised inflation and short-rate expectations, lowered nominal and real term premia and inflation risk premia, and increased nominal bond safety premia, suggestive of signaling, portfolio rebalance, and safe asset scarcity effects. Furthermore, we document spillover effects of ECB’s QE programs on Swedish bond markets that are similar to the Swedish QE effects only after controlling for exchange rate fluctuations, highlighting the importance of exchange rate dynamics in the transmission of QE spillover effects.

Research on vibration characteristics of cone valve based on steady state hydrodynamics

The steady-state fluid dynamic force of the cone valve core reduces the stability of the cone valve, thereby affecting its vibration characteristics. This study first derived the formula for calculating the steady-state fluid dynamic force of the valve core using the momentum theorem. Then, the study used the Computational Fluid Dynamics (CFD) method to explore the variation of steady-state fluid dynamic force with the opening degree of the cone valve and the pressure difference at the inlet and outlet. The study also analyzed the steady-state fluid dynamic force of the improved structure cone valve. Combining the CFD calculation results with the established axial vibration and dynamic models of the valve core spring system, a system dynamics simulation model was developed. Innovatively, the study combined experimental and simulation methods to investigate the vibration characteristics of the cone valve and the impact of steady-state fluid dynamic force on these characteristics. The experimental results aligned well with the simulation results, showing that the influence of steady-state fluid dynamic force on vibration characteristics is similar to that of spring force. At a small opening degree, the compensation structure of steady-state fluid dynamic force can reduce axial vibration amplitude. Increasing the inlet pressure from 2.0 MPa to 2.5 MPa results in a decrease in axial amplitude and an increase in the numerical value of the vibration balance position. Increasing the outlet pressure from 0.5 MPa to 0.9 MPa initially decreases axial amplitude and axial waveform factor, followed by an increase. Increasing the spring preload from 9.4 mm to 13.4 mm leads to a decrease in the numerical value of the balance position, a reduction in amplitude, and a decrease in the waveform factor of the axial vibration of the valve core. The study reveals systematic effects of inlet pressure, outlet pressure, and spring preload on the vibration characteristics of the cone valve. The research results in this paper can provide theoretical support for the structural design of hydraulic valves, reduce the impact of fluid dynamics on vibration, and thereby improve the stability of hydraulic system operation.

Concatenated Nanopore DNA Codes.

In nanopore sequencers, single-stranded DNA molecules (or k-mers) enter a small opening in a membrane called a nanopore and modulate the ionic current through the pore, producing a channel output in the form of a noisy piecewise constant signal. An important problem in DNA-based data storage is finding a set of k-mers, i.e. a DNA code, that is robust against noisy sample duplication introduced by nanopore sequencers. Good DNA codes should contain as many k-mers as possible that produce distinguishable current signals (squiggles) as measured by the sequencer. The dissimilarity between squiggles can be estimated using a bound on their pairwise error probability, which is used as a metric for code design. Unfortunately, code construction using the union bound is limited to small k's due to the difficulty of finding maximum cliques in large graphs. In this paper, we construct large codes by concatenating codewords from a base code, thereby packing more information in a single strand while retaining the storage efficiency of the base code. To facilitate decoding, we include a circumfix in the base code to reduce the effect of the nanopore channel memory. We show that the decoding complexity scales as [Formula: see text], where m is the number of concatenated k-mers. Simulations show that the base code error rate is stable as m increases.

Bashimyzon cheni, a new genus and species of sucker loach (Teleostei, Gastromyzontidae) from South China

Bashimyzon, new genus, is here established for Erromyzon damingshanensis, and a new species of the genus is described from the You-Jiang of the Pearl River (=Zhu-Jiang in mandarin Chinese) basin in Guangxi Province, South China. This new genus has a small gill opening above the pectoral-fin base and short pectoral fins extending backwards short of pelvic-fin insertions, both characters combined to separate it from all currently-recognized gastromyzontid genera except Erromyzon and Protomyzon, but differs from the two genera in having a larger gap between the posterior edge of eye and the vertical through the pectoral-fin insertion and very small fleshy lobes posterior to the maxillary-barbel bases. It is further distinct from its most similar genus Erromyzon in having a relatively larger gill opening, fewer branched pectoral-fin rays folded against body, and more posteriorly placed pectoral fins with a shorter fin base. Bashimyzon cheni, new species, and B. damingshanensis, the single congeneric species, differ in number of lateral-line pored scales, body coloration, and cephalic contour, and also in substantial genetic divergence.

Uncrewed aerial vehicle with onboard winch system for rapid, cost-effective, and safe oceanographic profiling in hazardous and inaccessible areas

Interactions between coastal waters and marine-terminating glaciers in the Polar Regions play a significant role in global sea level rise fueled by a rapidly warming Arctic.The risk of glacier calving, and the abundance of ice, can make it impossible for surface vessels to access the waters near glacier termini. Alternative methods using manned aircraft are expensive. As a result, oceanographic measurements are limited near glacier termini.We present an uncrewed aerial vehicle (UAV) with an on-board winch system that allows oceanographic profiling in remote, hazardous areas using a commercial conductivity, temperature, and depth (CTD) sensor payload. The UAV is optimized for easy handling and deployment and is capable of high-speed and efficient cruise flight. An autopilot system provides pilot assistance and autonomous flight capabilities. The total weight of the UAV including payload is 6.5 kg with an endurance of 24 min.Testing of the system was conducted in South Greenland during winter conditions in March 2023 with successful profiles collected near a glacier terminus (<5 m) and in small openings in ice mélange (2.2 m). The system proved capable, reliable, and efficient. Further development of the system will allow other sensors for an even more flexible measurement suite.

Effects of confinement geometry on shape transition and interfacial behavior of nanodroplets in externally applied electric field

The electric field-induced shape transition of a nanodroplet confined in a silicon nanogroove with variable structure was investigated through molecular dynamics simulations. Our work provides insight into the relationship between the shape transition and the molecular interaction. We demonstrated that the geometric structure of the groove significantly influences the responsive behaviors of the droplet to the electric field. The simulations elucidate increasing the tilt angle of the groove reduces the critical field strength for the shape transition of the droplet under parallel electric field. Above the critical field, the droplet detaches from the groove and forms a liquid bridge across the groove, leading to weakened interfacial interactions. The detachment process of the droplet from the rectangular groove, which originates from the spreading of water molecules on perpendicular side walls, is different from the droplet initially confined in the groove with tilt angle higher than 90°. Under the perpendicular electric field, the droplet undergoes various shape transitions depending on the groove structure. In particular, the droplet in the groove with a moderate opening forms two asymmetrical liquid columns. The retraction behavior of the droplet in the groove with the small opening sheds light on the competition between interfacial interactions. The shape transition of droplets in the electric field due to the change of confinement nanostructures, such as liquid bridge, asymmetrical extension, branching and merging, is helpful to enrich the understanding of electrowetting and confinement dynamics of the droplets.

Limited Differences in Insect Herbivory on Young White Spruce Growing in Small Open Plantations and under Natural Canopies in Boreal Mixed Forests.

In managed boreal forests, both plantations and natural regeneration are used to re-establish a cohort of conifer trees following harvest or disturbance. Young trees in open plantations generally grow more rapidly than under forest canopies, but more rapid growth could be compromised by greater insect damage. We compared insect damage on white spruce (Picea glauca (Moench) Voss, Pinaceae) growing in plantations with naturally regenerated trees under mature forest canopies in boreal forests (Québec, Canada). We selected ten sites in the naturally regenerated forest and in small, multispecies plantations and sampled ten young trees of 2.5-3 m (per site) in late summer 2020 and again in early and late summer 2021. We compared overall rates of herbivory, galls (adelgids), damage by the spruce budworm (Choristoneura fumiferana, Clemens), and defoliation from sawflies. Overall, insect herbivory damage remained at similarly low levels in both habitats; an average of 9.3% of expanding shoots were damaged on forest trees and 7.7% in plantation trees. Spruce budworm damage increased from 2020 to 2021 and remained higher in under-canopy trees, but damage rates were negligible at this early stage of the outbreak (1.5% in forest vs. 0.78% of buds damaged on plantation trees). While damage due to galls was higher in plantations, the overall low level of damage likely does not pose a significant impact on the growth or mortality of young trees.

PRPF19 mRNA Encodes a Small Open Reading Frame That Is Important for Viability of Human Cells.

High-throughput ribosome profiling demonstrates the translation of thousands of small open reading frames located in the 5' untranslated regions of messenger RNAs (upstream ORFs). Upstream ORF can both perform a regulatory function by influencing the translation of the downstream main ORF and encode a small functional protein or microprotein. In this work, we showed that the 5' untranslated region of the PRPF19 mRNA encodes an upstream ORF that is translated in human cells. Inactivation of this upstream ORF reduces the viability of human cells.

Purse-string skin closure versus linear skin closure in people undergoing stoma reversal.

Stoma reversal is associated with a relatively high risk of surgical site infection (SSI), occurring in up to 40% of cases. This may be explained by the presence of microorganisms around the stoma site, and possible contamination with the intestinal contents during the open-end manipulation of the bowel, making the stoma closure site a clean-contaminated wound. The conventional technique for stoma reversal is linear skin closure (LSC). The purse-string skin closure (PSSC) technique (circumferential skin approximation) creates a small opening in the centre of the wound, enabling free drainage of contaminants and serous fluid. This could decrease the risk of SSI compared with LSC. To assess the effects of purse-string skin closure compared with linear skin closure in people undergoing stoma reversal. We searched CENTRAL, MEDLINE, Embase, two other databases, and three trials registers on 21 December 2022. We also checked references, searched for citations, and contacted study authors to identify additional studies. We included all randomised controlled trials (RCTs) comparing PSSC and LSC techniques in people undergoing closure of stoma (loop ileostomy, end ileostomy, loop colostomy, or end colostomy) created for any indication. Two review authors independently selected eligible studies, extracted data, evaluated the methodological quality of the included studies, and conducted the analyses. The most clinically relevant outcomes were SSI, participant satisfaction, incisional hernia, and operative time. We calculated odds ratios (ORs) for dichotomous data and mean differences (MDs) for continuous data, each with its corresponding 95% confidence interval (CI). We used the GRADE approach to rate the certainty of the evidence. Nine RCTs involving 757 participants were eligible for inclusion. Eight studies recruited only adults (aged 18 years and older), and one study included people aged 12 years and older. The participants underwent elective reversal of either ileostomy (82%) or colostomy (18%). We considered all studies at high risk of performance and detection bias (lack of blinding) and four studies at unclear risk of selection bias related to random sequence generation. PSSC compared with LSC likely reduces the risk of SSI (OR 0.17, 95% CI 0.09 to 0.29; I2 = 0%; 9 studies, 757 participants; moderate-certainty evidence). The anticipated absolute risk of SSI is 52 per 1000 people who have PSSC and 243 per 1000 people who have LSC. The likelihood of being very satisfied or satisfied with stoma closure may be higher amongst people who have PSSC compared with people who have LSC (100% vs 89%; OR 20.11, 95% CI 1.09 to 369.88; 2 studies, 122 participants; low-certainty evidence). The results of the analysis suggest that PSSC compared with LSC may have little or no effect on the risk of incisional hernia (OR 0.51, 95% CI 0.07 to 3.70; I2 = 49%; 4 studies, 297 participants; very low-certainty evidence) and operative time (MD -2.67 minutes, 95% CI -8.56 to 3.22; I2 = 65%; 6 studies, 460 participants; very low-certainty evidence). PSSC compared with LSC likely reduces the risk of SSI in people undergoing reversal of stoma. People who have PSSC may be more satisfied with the result compared with people who have LSC. There may be little or no difference between the skin closure techniques in terms of incisional hernia and operative time, though the evidence for these two outcomes is very uncertain.

Light-dependent expression and accumulation of miR408-encoded peptide, miPEP408, is regulated by HY5 in Arabidopsis

Recent studies propose that primary transcripts of miRNAs (pri-miRNAs) contain small Open Reading Frames (ORFs) capable of encoding miRNA-encoded peptides (miPEPs). These miPEPs can function as transcriptional regulators for their corresponding pri-miRNAs, ultimately enhancing mature miRNA accumulation. Notably, pri-miR408 encodes the functional peptide miPEP408, regulating expression of miR408 and its target genes, providing plant tolerance to stresses. While miPEPs are crucial regulators, the factors governing them are have not been studied in detail. Here, we explored the light-dependent regulation of miPEP408 in Arabidopsis. Expression analysis during dark-light transitions revealed light-induced transcription and accumulation of the miPEP408. As the promoter of miR408 contains cis-acting elements responsible for binding to the bZIP-type transcription factor ELONGATED HYPOCOTYL5 (HY5), known for light-mediated regulation in plants, we studied its involvement in the regulation of miR408. Analysis of HY5 mutant (hy5-215), complemented line (HY5OX/hy5), and CONSTITUTIVE PHOTOMORPHOGENIC 1 mutant (cop1-4) plants supported HY5's positive regulation of miPEP408. Grafting and GUS assays further suggested the role of HY5 as a shoot-root mobile signal inducing light-dependent miPEP408 expression. This study underscores the regulatory impact of light on small peptides, exemplified by miPEP408, mediated by the key transcription factor HY5.

Numerical Investigation of Reinforced Concrete Beams with Single and Multi-Longitudinal Hollow Openings

This numerical study was conducted to evaluate the effect of longitudinal hollow openings in reinforced concrete beams. The study was divided into three groups: The first group: was circular holes of different sizes. The second group: different shaped openings (circular, square, rectangular). The third group: the number of openings (one, two, three). Abaqus software was used to analyze the behavior of reinforced concrete beams with hollow openings. The following effects of hollow openings were studied (effect on bending resistance, effect on beam deformations). The results also showed that the presence of hollow openings leads to increased threshold deformations. The results also show that the aperture size has a significant effect on the threshold deformations. Sills with large openings have a greater negative impact on sill deformations compared to sills with small openings. Concrete beams' longitudinal circular hole provides greater load-bearing than rectangular or square slots. Increasing the number of longitudinal holes provides greater load-bearing, but increasing the number reduces the load-bearing. Concrete with longitudinal slots is cheaper and lighter than hollow concrete openings and is used in buildings on a limited budget. Circular slots (10.46% difference) are better than rectangular (18.60% difference) and square (19.76% difference). One hole (10.46% difference) is better than two holes (18.60% difference) and three holes (19.76% difference).

The role of CFRP strengthening in improving the punching shear behavior of heat-damaged flat slabs with openings of different sizes and locations

The punching shear behavior of twenty simply supported RC flat slabs of mm3) dimensions was examined in this study where concentrated loading was applied using a 150 mm central square column. However, the effect of the following parameters was evaluated: (1) CFRP strengthening, (2) ambient and elevated temperatures (23 C, 200 C, 400 C, and 600 C), (3) opening existence (with or without), (4) opening location (directly at the column face or 60 mm a way), and (5) square opening side length (70 mm or 200 mm). Strengthening was done by four 75 mm wide CFRP strips applied at the bottom face of the slab to surround the column and opening region. It was found that the cracking intensity is directly affected by the exposure temperature with the cracking visibility at the opening internal sides. In addition, strengthening increases the slab’s stiffness by larger percentages for slabs with small openings compared to those with larger ones at ambient and normal temperatures with the differences being reduced at higher temperatures. Moreover, strengthening plays a major role in improving the slab’s deflection capacities by 10–90 % compared to the control specimen. Finally, the punching shear failure brittleness was significantly reduced by the CFRP-strengthening as the ductility of the strengthened specimens was increased as a result of the cracking intensity reduction.

Operating Force Characteristics of Sector Gates Based on Prototype Testing

With the widespread use of sector gates in tidal river locks, there is a growing interest in the operating force during the gate operation. This study investigates the characteristics of operating forces in a sector gate hydraulic cylinder system using prototype testing and focuses on the effects of different heads and flow velocities under the operating forces. The results reveal significant differences in the opening processes between normal and reverse heads, with head differentials and direction playing crucial roles in determining the operating force under flowing conditions. In still water, both gate opening and closing processes are divided into four and three stages, respectively, with the operating force remaining stable during the low-force operation stage. In particular, during gate closure under flowing conditions, flow velocity emerges as a key factor influencing the operating force, with the force during the small gate opening stage exhibiting a parabolic relationship with flow velocity. These findings provide valuable insights for the design and selection of hydraulic gate control systems, contributing to the safe operation of gates and efficient navigation of waterways.

Optimizing compressive capacity: A comprehensive study on cast-in-situ phosphogypsum walls with varied high-thickness ratios and eccentricity distances

The problem of pollution caused by the massive accumulation of phosphogypsum has become a worldwide problem. In order to realize the application of cast-in-place phosphogypsum walls (CPGW) as vertically stressed members in low-rise buildings with small openings, this paper investigates the compressive bearing capacity of CPGW and its calculation method. A total of 62, 5 sets of CPGW specimens were fabricated for compression testing. By analyzing the effects of different high-thickness ratios and eccentricity distances on the failure characteristics and compressive bearing capacity of CPGW, the mechanism of high-thickness ratios and eccentricity distances on the bearing capacity of CPGW is revealed, and the method of calculating the bearing capacity of CPGW is established. The results showed that three types of brittle failure occurred in CPGW: top splitting failure, conical failure and root fracture failure. The high-thickness ratio and eccentricity distance had a significant effect on the compressive bearing capacity of CPGW. In addition, the calculation method of CPGW compressive bearing capacity was established. Comparison of the formulae calculated values with the test values verified the feasibility and accuracy of the proposed calculation method. This study can provide theoretical reference for the engineering application of CPGW.

Flow over a radiating multi-filamentous structure with various opening angles: From disk-like to cone-like shape

Flow over a radiating multi-filamentous structure with various opening angles has been investigated numerically at low and moderate Reynolds numbers. The opening angle, as the major geometric parameter for investigation, varies from 180° to 40° and the overall shape changes from disk-like to cone-like. The overall model drag decreases monotonously as the magnitude of the opening angle decreases. The opening angle effects on the drag-enhancement are then investigated in terms of the velocity distributions, the structures of the recirculation region, and the pressure distributions. As the Reynolds number increases, the wake structure loses its steadiness and the optimal opening angle is found to be approximately 60° when the critical Reynolds number for a steady recirculation structure becomes maximum. The opening angle effects on the wake steadiness in terms of the intensity of the shear layer are investigated as well. On the one hand, the exit velocity—a quantitative indication of the rate of the base bleed—decreases with the decreasing of the opening angle, which promotes wake unsteadiness. This phenomenon can be attributed to the effective gap width between adjacent filaments and the intensity of the virtual barrier from both macro- and micro-perspectives. On the other hand, a small opening angle decreases the thickness of shear layer and thus the unsteadiness is suppressed. These two effects compete and the balance is reached when the opening angle is near 60°.

Liquid evaporation from nanochannel in the presence of non-condensable gas by direct simulation Monte Carlo

Liquid-vapor phase change in the form of evaporation and with the confinement of nanostructures is of vast importance in many engineering applications. The direct simulation Monte Carlo (DSMC) approach was employed to simulate the liquid evaporation from two-dimensional nanochannels in the presence of non-condensable (NC) gases. The thermodynamic properties of vapor and NC gas flow fields as well as the evaporation rate of liquid were calculated. Factors such as channel opening ratio, meniscus receding depth and the NC gas density were examined to reveal their impacts on the liquid evaporation rates. The results showed that the gas mixture flow field transforms to one-dimensional away from the channel exit. The overall vapor pressure drop can be divided into that across the liquid–vapor interface, that within the channel, outside the channel, as well as that caused by the binary diffusion. The effect of NC gas on the evaporation rate was found to be the most outstanding with pinned meniscus and with a wide channel opening, in which case the normalized evaporation rate drops to 0.43. Moreover, the Maxwell-Stefan equation could capture the evaporation data with modified diffusion lengths. For receded meniscus (250 nm deep) and small opening ratio (0.417), the effective diffusion length was as large as 1.6 times that in the one-dimensional case.

How Effective Are Palm-Fiber-Based Erosion Control Blankets (ECB) against Natural Rainfall?

Rainfall-induced soil erosion is a significant environmental issue that can lead to soil degradation and loss of vegetation. The estimated global annual loss increased by 2.5% over 11 years, from 35 billion tons in 2001 to 35.9 billion tons in 2012, mainly due to spatial changes. Indonesia is predicted to be among the largest and most intensively eroded regions among countries with higher soil erosion, regarded as hot-spots higher than 20 Mg yr−1 ha−1. Due to climate change, natural rainfall patterns in the tropical regions have been subject to change, with a lower number of rainy days and increased intensity of precipitation. Such changes trigger more soil erosion due to heavier rainfall kicking up dried soil particles that are exposed in the bare embankments. Unfortunately, there is no prevention available in developing countries due to the lack of availability and high prices of mitigation techniques such as terraces and covering areas with geotextiles or blankets. Erosion control blankets (ECBs) have emerged as a potential solution to mitigate soil erosion. This research article aims to evaluate the effectiveness of sugar-palm-fiber-based ECB in reducing soil erosion caused by natural rainfall. The study investigates the effectiveness of sugar-palm-based ECB in protecting against erosion at the designated embankment. During the three months of typical rainy seasons (February to April 2023), total eroded mass (kg) was collected and measured from two adjacent microplots (10 m2 each), one covered with ECB and the other one left as uncovered soil (bare soil). The results indicate that eroded mass is proportional to rainfall, with coefficients of 0.4 and 0.04 for bare soil and ECB-covered embankments, respectively. The total soil loss recorded during the monitoring period was 154.6 kg and 16.7 kg for bare and ECB-covered soil, respectively. The significantly high efficiency of the up to 90% reduction in soil losses was achieved by covering the slope with sugar-palm-fiber-based ECB. The reason for this may be attributed to the intrinsic surface properties of sugar palm fiber ropes and the soil characteristics of the plot area. Sugar palm (Arenga pinnata) fiber has higher lignocellulosic contents that produce a perfect combination of strong mechanical properties (higher tensile strength and young modulus) and a higher resistance to weathering processes. Although the cost of production of handmade sugar-palm-fiber-based ECB is now as high as 4 EUR, further reductions in cost production can be achieved by introducing machinery. Compared to typical ECBs which have smaller openings, sugar-palm-based ECB has larger openings that allow for vegetation to grow and provide it with a lower density. As such, we recommend improvements in the quality of palm-fiber-based ECB via the introduction of further automation in the production process, so that the price can be reduced in line with other commercially available natural fibers such as jute and coir.

Investigation of the accuracy of dynamic condylar position: A model study

ObjectivesTo evaluate dynamic condylar positions by integrating mandibular movement recording data and cone-beam computed tomography (CBCT) and to investigate its accuracy via dynamic model experiments. MethodsA polyvinyl chloride skull model was utilized. A robot arm was used to operate the mandible to perform mouth opening, closing, protrusion, and lateral movements. A recording device, worn on the skull, was used to record the dynamic process and an optical position tracking (OPT) system was used to simultaneously trace the movements. A self-developed software module was used to evaluate the dynamic condylar position by integrating the dynamic tracing data and a virtual skull model derived from CBCT images. Errors were defined as differences between the dynamic coordinates of six landmarks around the condylar area derived from the software module (test) and OPT system (gold standard). ResultsThe condylar position errors were 0.76 ± 0.31, 0.55 ± 0.15, and 0.68 ± 0.23 mm for mouth opening, bilateral, and protrusion movements, respectively. Furthermore, the errors for small, moderate, and large mouth opening movements were 0.62 ± 0.19, 0.69 ± 0.29, and 0.94 ± 0.31 mm, respectively. The errors for all movements, except for large mouth opening, were significantly less than 1 mm (P < 0.05). The error was not different from 1 mm in the large mouth opening movement (P > 0.05). ConclusionsOur developed method of achieving dynamic condylar position by integrating mandibular movement recording data and CBCT images is clinically reliable. Clinical significanceThis study proved the reliability of evaluating dynamic condylar position using a commercial dynamic recording instrument and CBCT images.

NLFEA of the Behavior of Polypropylene-Fiber-Reinforced Concrete Slabs with Square Opening

The bending behavior of one-war reinforced concrete (RC) slabs with polypropylene fibers (PF) was examined in this study under the effect of different opening ratios using the nonlinear finite element analysis (NLFEA) method. The investigated parameters include the effect of different square opening ratios between 0 and 24% and PF volume percentages between 0 and 1% with 0.1% increments. The objectives of this study were fulfilled using 88 NLFEA models with different combinations of the studied parameters, including 11 control slabs without openings. The slab’s behavior was studied focusing on different structural performance characteristics, such as ductility, using energy-based and deflection-based approaches, stiffness (initial and yielding), cracking, and ultimate load strength. In addition, other structural performance parameters were considered, such as the crack opening, failure modes, and strain values, which were recorded for all specimens during the loading history. Moreover, the load-carrying capacity of the slabs was compared, looking at the NLFEA method’s results and the theoretical prediction results based on the sectional analysis method. However, it was observed that the inclusion of PFs of different percentages has a superior effect on the behavior of RC slabs with small openings (less than 2% opening ratio) compared to the acceptable improvements obtained for sabs with larger opening sizes. Consequently, PF could be utilized as a replacement for conventional steel rebars for RC slabs with small openings. In addition, increasing the PF percentage increases the resulting crack-opening value at failure due to the provided stabilization effect, in addition to increasing the system’s ability to sustain loads.