Cross-sectional Size Research Articles

An Increase in The Cross-Section of Two-Photon Absorption of Styrene Dye in Supramolecular Complexes with Cucurbituriles

Two-photon absorption cross sections of aqueous solutions of the styryl dye trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide (DASPI) and its inclusion complexes with cucurbit[n]urils (CB[n] n = 6–8) were measured using fluorescence spectroscopy. A nonmonotonic dependence of the cross-section size on the excitation wavelength and on the cavitand cavity size was found. Compared with a free dye, a sevenfold increase in the two-photon absorption cross section was observed in DASPI inclusion complexes with CB[8] at an excitation wavelength of 980 nm.

Analytical relations for fields and currents in magnetic-pulsed «expansion» of tubular conductors of small diameter

Introduction. This work was initiated by the problems of cardiovascular diseases, which are one of the main causes of mortality of the population of our planet. More than ten years ago, in 2012, approximately 3.7 million people died of acute coronary syndrome worldwide. The fight against such pathologies is carried out with the help of so-called stents, the manufacture of which can be carried out by the method of magnetic pulse «expansion» from hollow metal cylinders. The limited production possibilities of magnetic pulse «expansion» were caused by the minimum cross-sectional size of the inductor-instrument, which can be practically manufactured. Other tools are required to perform this operation. Novelty. A system of magnetic-pulse expansion of thin-walled pipes of small diameter with an inductor that excites an azimuthal electromagnetic field in the case of direct current passing through the processing object and in the absence of its connection in an electric circuit with an inductor is proposed. Purpose. The main analytical dependencies for the characteristics of the electromagnetic processes taking place in the inductor systems for the expansion of cylindrical conductive pipes of small diameter when direct passage of current through the processed object and when it is not connected to an electric circuit with an inductor (insulated billet) is derived. Methods. The solution of the boundary value problem with given boundary conditions was carried out by applying Laplace transforms and integrating Maxwell’s equations. Results. Analytical expressions were obtained for the main characteristics of the processes: the intensities of the excited electromagnetic fields and currents in the system depending on the parameters of the studied systems. The analysis of possible technical schemes for solving the given problem indicated the choice of the optimal variant of an effective system of magnetic-pulse «stretching» of thin-walled cylindrical conductors of small diameter. Practical value. Based on the qualitative analysis of the obtained results, recommendations for the practical implementation of the proposed system were formulated. The obtained dependences allow us to give numerical estimates of the effectiveness of excitation of magnetic pressure forces on the object of processing and to choose directions for further improvement of the magnetic pulse technology for solving such problems. References 23, figures 2.

HouShiHeiSan attenuates sarcopenia in middle cerebral artery occlusion (MCAO) rats

Ethnopharmacological relevancePhysical therapy is the main clinical treatment for limb symptoms after ischemic stroke, and there is a lack of reliable drug intervention programs. HouShiHeiSan (HS)comes from “Synopsis of the Golden Chamber”, where it is recorded: “seauelae of wind stroke and heaviness of limbs”, indicating this formulae is a promising opion for clinical practice. Aim of the studyThe aim of this study is to explore the therapeutic effect of HS on sarcopenia after ischemic stroke (ISS) by using the middle cerebral artery occlusion (MCAO) rats. Materials and methodsAfter 7 days of adaptive feeding Sprague-Dawley (SD) rats were randomly divided into sham and MCAO surgery groups. After MCAO operation, the agreement of the models was evaluated with a laser speckle instrument, and then, treatment groups were administered HS and related solvent. During the 7 days treatment period, the Zea-Longa score was used to assess the neural function, the treadmill for exercise capacity and traction instrument for grip strength. Besides, the physiological electrical signal system was used to record muscular electrical signals, while the muscle thickness was measured by ultrasound. After data acquisition on the 7th day after MCAO operation, the soleus muscle was dissected, and the indexes of length, weight of whole muscle tissue and cross-sectional area of muscular cells by H&E were recorded. Subsequently, mechanistic indicators were examined. MuRF1 and MAFbx expression was detected by immunohistochemistry (IHC). Furthermore, the expression level of more related indicators of muscular differentiation and cellular proterin balance, including mTOR, p-mTOR, AKT, p-AKT, p70s6k, p-p70s6, FOXO1, p-FOXO1, MyoD1, Myostatin, MuRF1 and MAFbx, were tested via Western blot. ResultsHS improved motor performance and promoted muscle regeneration in MCAO rats. In terms of motor ability, HS mixed with alcohol significantly improved the neurological function damage, reduce the weight loss, increase the running distance per unit time and increase the grip strength. The postoperative muscle electrical signal intensity increased, and muscle thickness, weight, and length were maintained. The HS with alcohol group significantly maintained the cross-sectional size of muscle cells and reduced the number of MyoD1 and myostatin-positive cells in the muscle tissue. It simultaneously promoted the expression of p-mTOR, p-AKT, p-p70s6k, and MyoD1 to promote the synthesis of muscle proteins and inhibited the expression of p-FOXO1, myostatin, MAFbx, and MuRF1 to reduce muscle protein degradation. ConclusionHS can enhance muscle protein synthesis and decrease protein breakdown by activating the AKT/mTOR/FOXO1 pathway, thereby preserving muscle health and enhancing motor performance following stroke in rats.

Application of Multiple Linear Regression Method in Steel Column Design under Combined Loading

The article explores using multiple linear regression (MLR) approach to predict the cross-section of beam-column steel members. These members are complex in design, as they must withstand bending and axial forces. The design process involves multiple safety checks according to design standards. The first step in the design procedure is to calculate and verify the axial capacity of the member. Following that, the flexural capacity is calculated. Finally, the combined load capacity is examined, often involving a trial-and-error process. If the initially selected section cannot withstand the applied forces, a new section must be chosen, and the calculations must be repeated. This study employs a multiple linear regression approach to investigate the relationship between member properties (such as length and cross-section) and load design parameters (axial and bending forces). The primary objective is to predict the beam-column steel member’s elastic section modulus (Sx). The regression equation derived from the study is as follows: Sx = 18.000L + 6.839Pr + 47.193Mr – 129.093, with an R-square value of 0.985. The histogram of the equation exhibits symmetry and a standard distribution, while the typical probability plot demonstrates a relatively linear trend. Two examples are presented to evaluate the efficiency of the regression equation. The first example confirms the efficiency of the equation by determining the cross-sectional size by employing the regression equation and using it to verify the safety according to EIT design standards. The second example is the application of the equation for estimating the size of other types of steel members. This study suggests that the regression equation can effectively predict the size of beam-column steel members, providing reliable results for practical design applications.

Evaluating the Role of Rectus Abdominis Fat Transfer (RAFT) in Improving Muscle Thickness: Does it Really Work? A 12-Month Follow-Up Cohort Study.

Looking for an adequate solution for those patients who desire abdominal definition, but are not candidates for liposuction alone, Danilla developed a technique, using selective fat grafting into the rectus abdominis (RAFT) to increase the muscle volume in addition to selective liposuction and abdominoplasty to provide an optimal body contouring. To determine whether intramuscular fat grafting in the rectus abdominis muscles leads to an increase in muscle thickness after one year. This is a prospective cohort study, from a single center, carried out over 24 months (October 2021-September 2023). Sixty-two patients who underwent lipoabdominoplasty and RAFT, had their rectus abdominis cross section measured by ultrasound pre- and 12 months postoperatively. To compare the muscle thickness, a paired t-test statistic was used. A p-value of 0.05 was considered statistically significant (IBM SPSS Statistics V26). After 1 year, all 62 patients showed an increase in the size of the rectus muscle cross section, although only 58 (94%) had fat identifiable in the US. Preoperatively, the mean muscle cross-sectional size was 1, 4cm. After RAFT, overall mean muscle cross section was 2, 3cm (0, 9cm/66.9% increase). When stratified into groups with and without identifiable fat, the group in which the graft remained showed greater increase than the group with no visible fat (69, 9% vs 19,6%). The RAFT provided a significant increase in the muscle cross section in most cases after 1 year. The presence of fat is related to a statistically significant increase in the muscle compartment (pack). This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Numerical investigation on flexural performance of dowel laminated timber with laminas made of laminated veneer lumber

Horizontal dowel laminated timber (H-DLT) is a doweled engineered wood product with laminas made of solid timber. H-DLT has excellent bending resistance. However, the height of cross-section of H-DLT as a beam is limited by the width of solid wood laminas. Laminated veneer lumber (LVL) is an engineered wood product formed by hot-pressed gluing thin veneers, which is flexible in cross-section size compared to solid timber. Horizontal dowel laminated veneer lumber (H-DLVL) was developed by utilizing the H-DLT production methods and LVL material characteristics. H-DLVL has flexible size and good mechanical properties, and it can be made into beams and panels with large cross-sections. In this paper, the flexural performance of H-DLVL beams was investigated. A predictive finite element model of H-DLVL beams was created by the extended finite element method (XFEM) with cohesive zone model (CZM). The numerical models using solid-beam elements without fictitious cracks were verified and calibrated by experimental results. The influence of five variables, including lamina width, thickness, and quantity, dowel spacing along the grain, and dowel row (edge distance), on the flexural performance of H-DLVL beams was analyzed, and the flexural strength of H-DLVL beams was parameterized. The results showed that the failure mode of H-DLVL beams could be well predicted by XFEM without considering fictitious cracks combined with CZM, and the error range of simulated flexural strength of H-DLVL beams was within ±10 %. The flexural strength of H-DLVL beams was directly affected by lamina thickness and dowel spacing along the grain. The flexural strength of H-DLVL beams increased with the increase of those two variables. Lamina width and dowel row (edge distance) affected the flexural strength of H-DLVL beams indirectly by influencing the failure mode of H-DLVL beams. Based on this research, the recommended dowel spacing along the grain of H-DLVL beams was 6.25–12.5 times the wood dowel diameter, and the recommended edge distance of H-DLVL beams was 5–7 times.

Strategic Thinking: A Resource to Generate Value and Cross the Valley of Death of SMEs

The most challenging period for a company is the first three years following its inception, a period often referred to as the "valley of death." This article examines the factors contributing to the high mortality rate of small and medium-sized enterprises (SMEs) in the town of Melipilla, Chile, and presents potential strategies for reducing or preventing this mortality. The study employs an exploratory-descriptive approach, utilizing a qualitative methodology and a cross-sectional sample size collected through convenience sampling and semi-structured interviews. Upon analysis of the aforementioned data, it becomes evident that contemporary SMEs have more convenient access to capital, technology, information, and financing. These resources, which were once considered distinctive and crucial for competitive advantage, are no longer as pivotal in generating value. Conversely, the findings highlight the pivotal role of human resources and their strategic management in developing distinctive competencies, which are essential for SMEs to create value and ensure long-term sustainability.

Nutrition and Periodontitis: A Cross-Sectional Study from a Practice-Based Research Network.

Despite clinical interventional studies on the influence of diet on periodontal inflammatory parameters, there has been no practice-based cross-sectional study from a German population to date that has conducted both a comprehensive dental and periodontal examination and a thorough validated assessment of dietary behavior. Therefore, the aim of this pilot study was to evaluate, in a proof of concept, whether there is a correlation between the overall periodontal inflammatory surface area (PISA), periodontal clinical parameters (pocket probing depths (PPD), clinical attachment loss (CAL), bleeding on probing (BOP), furcation involvement (FI), tooth mobility (TM)), and the dietary behavior of patients with periodontal disease when utilizing a practice-based research network. The primary outcome was the correlation between the periodontal inflammatory surface (PISA) and the dietary assessment data. The practice-based research network, consisting of eight Master's graduates, recruited patients who met the inclusion and exclusion criteria and performed a periodontal examination together with the assessment of dietary behavior using a digital version of the validated retrospective dietary recall (DEGS/RKI). Statistical analyses included linear regression models adjusted for age and smoking and unpaired t-tests, conducted using STATA 17.0 with a significance level of 5%. In addition, the data obtained were classified according to the currently recommended amounts of daily intake. A total of 1283 teeth were analyzed, with 60.25% (773 teeth) requiring treatment. The average PISA was 753.16 mm2 (SD ± 535.75 mm). Based on dietary guidelines, the studied population consumed excessive amounts of extrinsic sugars and fats, while their fiber and legume intake was insufficient. The intake of certain nutrients, including water-soluble fibers, specific fatty acids, vitamins (D, B1, B2, B6, and B12), iron, and zinc, was associated with reduced PISA, PPD, CAL, and BOP. Within the limits of the current study, including its cross-sectional design and cohort size, the outcomes demonstrated the influence of nutrition on periodontal health.

Effect of web holes on web crippling capacity of rectangular hollow steel sections under two flange loadings

This paper presents experimental and numerical investigations on web crippling behavior of hot rolled rectangular hollow section (RHS) with web holes. A total of 20 rectangular hollow sections, subjected to interior-two-flange (ITF) and end-two-flange (ETF) loading conditions undergoing web crippling, were experimentally tested. The experimental program was designed to obtain web crippling of specimen having slenderness (h/t) value of 21.32, by varying size and offset distance of web holes under two flange loading conditions. Finite element models of experimentally tested beams were developed, and results of finite element analysis showed good agreement with experimental results. A parametric study was then conducted using finite element analysis on different cross section sizes, to demonstrate the effect of size and position of web holes on web crippling capacity of rectangular hollow sections. It was demonstrated that ratio of diameter of web hole to the depth of flat portion of web (a/h) and ratio of offset distance of web hole to the flat portion of web (x/h) are the primary parameters affecting the web crippling strength. Design recommendations in the form of reduction factors for both loading conditions are proposed, that are conservative to both experimental and finite element results. To assess the reliability level of design recommendations, reliability analyses were undertaken.

Design of the Elastic Modulus of porous lattice structures composed of cells with continuously variable cross section carrying structures

BackgroundPorous bone implants have a wide range of applications for their low elastic modulus and good connectivity. It is necessary to explore an elastic modulus control method that can significantly regulate the elastic modulus under the condition of maintaining a constant porosity. MethodsFor achieving continuously changing elastic modulus of porous lattice structure, the simple cubic lattice structures were selected as research object, and the distribution of cross-sectional sizes of its carrying structures were set as variable continuous curves. The prediction model for the elastic modulus was established based on the elasticity mechanics and the equal mass assumption. Then, the prediction model is enhanced through compression simulation of the unit cell structure. Finally, the accuracy of prediction model is validated by compression experiments. FindingsThe results indicate that the distribution of cross-sectional size of the carrying structures has a significant impact on the elastic modulus of unit cell structures under the constraint of equal mass. By adjusting the characteristic parameters of distribution curves, the elastic modulus can be changed within a large range. InterpretationVariable cross-section can effectively change the elastic modulus of porous structures while ensuring constant porosity. This method has important value in decoupling the influence of geometric parameters on the elastic modulus of porous structures.

Flexural mechanical properties of H-shaped steel-bamboo scrimber composite beams

To improve the torsional buckling resistance and enhance the load-bearing capacity and ductility of H-shaped steel beams with carbon reduction materials, the concept of combining H-shaped steel with bamboo scrimber has been proposed, in which the bamboo scrimber, an eco-friendly, lightweight, and high-strength material, promises significant structural benefits. Five full-scale specimens were designed and tested, including one H-shaped steel, two bamboo scrimber beams, and two composite beams. Additionally, further simulation tests were conducted using the verified finite element model (FEM). The experimental results revealed a remarkable increase in the ultimate bearing capacity of the composite beams by 96.5 % compared to bamboo scrimber-only beams and 72.7 % compared to steel-only beams. Meanwhile, distinct from the brittle fracture characteristics of the bamboo scrimber beams, which include instantaneous crack propagation and interlaminar cracking, the composite beams exhibited localized vertical cracks within the beam's tensile zone, effectively avoiding the torsional buckling issue of the H-shaped steel beam. The results further demonstrated that increasing the cross-sectional size of the composite beams can significantly enhance their flexural stiffness (up to 669 %), and reduce the deflection at the ultimate flexural moment. When the area of the bamboo scrimber in the cross-section was reduced with an unchanged steel profile, the initial stiffness dropped to 79 % without incurring any structural instability. Furthermore, by integrating the experimental and simulation results, a fiber element model for this composite beam structure is proposed to predict the maximum flexural moment value in the ultimate state. A corresponding calculation program was developed, and it is found that the calculated predicted ultimate flexural moment values exhibited negligible deviation from both experimental and FEM results, with AV of 1.0001, AAE of 2.21 %, and COV of 3.28 %.

Mathematical modelling for strata deformation caused by rectangular pipe jacking construction in composite layered ground

In this study, analytical solutions of vertical deformation of ground surface and horizontal displacement of strata are derived combining the Mindlin solution and the mirror method due to rectangular pipe jacking tunneling in composite strata, which considers the combined effect of five factors of additional excavation pressure, friction of rectangular pipe jacking and soils, segment-soil friction, grouting filling and strata loss, respectively. The theoretical calculation results were verified against the measured data in two project cases. Moreover, effect factors of rectangular jacking pipe cross-sectional dimensions, embedment of tunnel axial depth, elasticity modulus on the interlayer and the Poisson's ratio of the interlayer on strata deformation is investigated. The results imply that the theoretical calculation values obtained using this method are more closely correlated with the observed values compared to those computed using the single stratum model. The primary cause of terrene upheaval in front of the working surface is the increased excavation pressure on the working face and the horizontal displacement of the deep soils and the surface subsidence behind the excavation face is resulting from the soil loss as the main influencing factor. The varying cross-section size of pipe jacking is able to impact on the vertical deformation of the soil, but it has a limited impact on the lateral displacement of the strata. The affection of the buried depth of the tunnel axis on strata deformation is more notable in the rectangular pipe jacking construction. As the axial tunnel depth growth, the ground surface maximum subsidence value gradually decreases, while the crest value of horizontal distortion mildly increases. When the rise of the interlayered modulus of elasticity, the maximum earth surface subsidence enlarged gradually while the subsidence trough slight diminution. Moreover, the greatest horizontal displacement exhibits a relatively minor fluctuation, but there is a trend of upward movement in the position. The influence of Poisson's ratio of the interlayer on the strata deformation is comparatively weak.

Axial compressive behavior of partially encased composite reactive powder concrete columns after high-temperature exposure

Replacing ordinary concrete in partially encased concrete (PEC) columns with high-strength and durability reactive powder concrete (RPC) significantly improves their axial capacity and suppresses local buckling of the steel section. To study the axial mechanical performance of partially encased composite reactive powder concrete (PEC-RPC) columns after exposure to high temperatures, axial compression tests of eight PEC-RPC column specimens were designed and conducted. Thermal response, failure modes, axial load-vertical displacement curves, and strain-axial strain curves of different specimens were observed considering the effects of link spacing, cross-sectional dimensions, constant temperature duration, and cooling methods. Results indicate: PEC-RPC columns exhibited whitening on the surface of RPC after high-temperature exposure, specimens with the largest link spacing experienced RPC peeling due to concentrated thermal stress, exacerbated by spraying water, which created a stress difference between the surface and the interior, resulting in RPC peeling. The deeper the thermocouple was embedded, the lower the measured temperature. Additionally, due to the significantly lower thermal conductivity of RPC compared to steel, the temperature at measurement points within the RPC is much lower than that at the steel web. The failure mode of PEC-RPC columns after axial loading was characterized by the crushing of RPC and local buckling of section steel. The larger the link spacing, the more prone it was to multi-layer buckling, and columns with larger cross-sectional sizes tended to exhibit shear failure. The characteristic value of mechanical performance showed higher sensitivity to cross-sectional dimensions, but relatively lower sensitivity to link spacing and constant temperature duration. As the cross-sectional dimensions increased from 150×150 mm to 250×250 mm, the peak load, residual bearing capacity, stiffness, and ductility increased by 72.51–164.86 %, 89.8–173.6 %, 61.85–151.47 %, and 13.72–31.46 %, respectively. Finally, based on partition constraint theory and superposition principle, a simplified method for calculating the axial mechanical performance of PEC-RPC columns after exposure to high temperatures was proposed.

Unified framework for laser-induced transient bubble dynamics within microchannels

Oscillatory flow in confined spaces is central to understanding physiological flows and rational design of synthetic periodic-actuation based micromachines. Using theory and experiments on oscillating flows generated through a laser-induced cavitation bubble, we associate the dynamic bubble size (fluid velocity) and bubble lifetime to the laser energy supplied—a control parameter in experiments. Employing different channel cross-section shapes, sizes and lengths, we demonstrate the characteristic scales for velocity, time and energy to depend solely on the channel geometry. Contrary to the generally assumed absence of instability in low Reynolds number flows (<1000\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$<1000$$\\end{document}), we report a momentary flow distortion that originates due to the boundary layer separation near channel walls during flow deceleration. The emergence of distorted laminar states is characterized using two stages. First the conditions for the onset of instabilities is analyzed using the Reynolds number and Womersley number for oscillating flows. Second the growth and the ability of an instability to prevail is analyzed using the convective time scale of the flow. Our findings inform rational design of microsystems leveraging pulsatile flows via cavitation-powered microactuation.

Cross-sectional size, shape, and estimated strength of the tibia, fibula and second metatarsal in female collegiate-level cross-country runners and soccer players

Bone stress injuries (BSIs) frequently occur in the leg and foot long bones of female distance runners. A potential means of preventing BSIs is to participate in multidirectional sports when younger to build a more robust skeleton. The current cross-sectional study compared differences in tibia, fibula, and second metatarsal diaphysis size, shape, and strength between female collegiate-level athletes specialized in cross-country running (RUN, n = 16) and soccer (SOC, n = 16). Assessments were performed using high-resolution peripheral quantitative computed tomography and outcomes corrected for measures at the radius diaphysis to control for selection bias and systemic differences between groups. The tibia in SOC had a 7.5 % larger total area than RUN, with a 29.4 % greater minimum second moment of area (IMIN) and 8.2 % greater estimated failure load (all p ≤ 0.02). Tibial values in SOC exceeded reference data indicating positive adaptation. In contrast, values in RUN were similar to reference data suggesting running induced limited tibial adaptation. RUN did have a larger ratio between their maximum second moment of area (IMAX) and IMIN than both SOC and reference values. This suggests the unidirectional loading associated with running altered tibial shape with material distributed more in the anteroposterior (IMAX) direction as opposed to the mediolateral (IMIN) direction. Comparatively, SOC had a similar IMAX/IMIN ratio to reference data suggesting the larger tibia in SOC resulted from multiplane adaptation. In addition to enhanced size and strength of their tibia, SOC had enhanced structure and strength of their fibula and second metatarsal. At both sites, polar moment of inertia was approximately 25 % larger in SOC compared to RUN (all p = 0.03). These data support calls for young female athletes to delay specialization in running and participate in multidirectional sports, like soccer, to build a more robust skeleton that is potentially more protected against BSIs.

Musculoskeletal Dimension and Brightness Reference Values in Lumbar Magnetic Resonance Imaging-A Radio-Anatomic Investigation in 80 Healthy Adult Individuals.

Background/Objectives: Magnetic resonance imaging (MRI) is the preferred diagnostic means to visualize spinal pathologies, and offers the possibility of precise structural tissue analysis. However, knowledge about MRI-based measurements of physiological cross-sectional musculoskeletal dimensions and associated tissue-specific average structural brightness in the lumbar spine of healthy young women and men is scarce. The current study was planned to investigate characteristic intersexual differences and to provide MRI-related musculoskeletal baseline values before the onset of biological aging. Methods: At a single medical center, lumbar MRI scans of 40 women and 40 men aged 20-40 years who presented with moderate nonspecific low back pain were retrospectively evaluated for sex-specific differences in cross-sectional sizes of the fifth lumbar vertebrae, psoas and posterior paravertebral muscles, and respective sex- and age-dependent average brightness alterations on T2-weighted axial sections in the L5-level. Results: In women (mean age 33.5 years ± 5.0 (standard deviation)), the investigated musculoskeletal cross-sectional area sizes were significantly smaller (p < 0.001) compared to those in men (mean age 33.0 years ± 5.7). Respective average musculoskeletal brightness values were higher in women compared to those in men, and most pronounced in posterior paravertebral muscles (p < 0.001). By correlating brightness results to those of subcutaneous fat tissue, all intersexual differences, including those between fifth lumbar vertebrae and psoas muscles, turned out to be statistically significant. This phenomenon was least pronounced in psoas muscles. Conclusions: Lumbar musculoskeletal parameters showed significantly larger dimensions of investigated anatomical structures in men compared to those in women aged 20-40 years, and an earlier onset and faster progress of bone loss and muscle degradation in women.

Performance Simulation of Muon Detectors Based on Structural Design and Array Layout of Plastic Scintillators

The performances of muon detectors have prominent effects on the accuracy and application scenario of muon imaging. Previous studies have paid more attention to the performance improvements of muon detectors in the assembly of imaging systems and optimization of imaging algorithms, while, the structural design and array layout of plastic scintillators in muon detectors have received less attention. In this work, the simulation models of plastic scintillator, wavelength-shifting (WLS) fibers, and muon source are constructed in the Geant4 software. On this basis, different factors affecting light collection efficiency (LCE) have been investigated, including muon hitting position, plastic scintillator cross-sectional shape and size, and WLS fiber size and position. Meanwhile, the influences of scintillator array layout, average width, and muon energy on the position resolution performance of the detector are investigated. The constructive results have been listed as follows: (a) the longitudinal length of the plastic scintillator unit, the shape and size of the WLS fiber, and the position of the WLS fiber have a large impact on the LCE. (b) The Right-angled triangle staggered layout is suitable for small-sized scintillators with single-energy muon hitting, and the Rhombus staggered layout is suitable for large-sized scintillators with multiple-energy muon hitting. This work provides theoretical support for the structural design and array layout of plastic Scintillators, and it has an important significance as a guide for the design of the subsequent muography system.

Fixed-[formula omitted] asymptotics for panel models with two-way clustering

This paper studies a cluster robust variance estimator proposed by Chiang, Hansen and Sasaki (2024) for linear panels. First, we show algebraically that this variance estimator (CHS estimator, hereafter) is a linear combination of three common variance estimators: the one-way unit cluster estimator, the “HAC of averages” estimator, and the “average of HACs” estimator. Based on this finding, we obtain a fixed-b asymptotic result for the CHS estimator and corresponding test statistics as the cross-section and time sample sizes jointly go to infinity. Furthermore, we propose two simple bias-corrected versions of the variance estimator and derive the fixed-b limits. In a simulation study, we find that the two bias-corrected variance estimators along with fixed-b critical values provide improvements in finite sample coverage probabilities. We illustrate the impact of bias-correction and use of the fixed-b critical values on inference in an empirical example on the relationship between industry profitability and market concentration.

Turbulent boundary layer structures downstream of a square cylinder

Particle image velocimetry is used to investigate the coherent structures within a turbulent boundary layer (TBL) perturbed by a slender square cylinder. A moderate Reynolds number of Reτ=3691 is considered. The cylinder is immersed in different vertical regions of the TBL, from the viscous sublayer to the logarithmic layer, depending on the value of the cylinder–wall gap ratio within the range of G/D=0.0−2.0. Here, G is the distance between the wall and the lower surface of the cylinder, and D is the cross-section size of the square cylinder. The results reveal a substantial influence of the TBL statistics and structures. Utilizing velocity correlation and proper orthogonal decomposition (POD), we highlight the intriguing influence of large-/very large-scale turbulent structures induced by the cylinder. When the cylinder is positioned on or in close proximity to the wall, periodic shedding of vortices is not apparent. In the presence of a cylinder, the large-/very large-scale turbulent structures are reduced in size compared with those in the undisturbed TBL, owing to the interaction between the flow around the cylinder and the boundary layer turbulence. The lower modes of the POD in the disturbed TBL are similar to those of the undisturbed flow field. However, the large-/very large-scale turbulent structures are increasingly affected by the strengthening of the shedding vortices with increasing G/D when the cylinder is located in the logarithmic region. As a result, the Kármán vortex street becomes the dominant structure associated with the higher POD modes at sufficiently high cylinder–wall gap ratios.

The influence of geographical location on moisture distribution in wood cross sections: a numerical simulation study using Austria as an example

Wood constantly interacts with the surrounding, locally varying climate, leading to changes in the moisture content. Advanced simulation tools can predict the two-dimensional moisture distributions caused by these changing climate conditions within wood cross sections over time. However, there is a notable absence of systematic simulation results for diverse climatic conditions and various wood cross sections. This study seeks to bridge this gap in research. Here, we present moisture fields in three solid timber and three glued laminated timber cross sections in Austria and show the effect of the location and the altitude on the moisture content distribution. The results reveal decreasing influence of the location on the moisture content development with increasing cross section size, and primarily the altitude affecting the moisture content. In addition, the results are compared with the standard for the design of timber–concrete composite structures (ONR CEN/TS 19103), revealing appropriate values in most of the cases. Only for cross sections with a width of 14 cm and larger, assigned to a specific region, the standard value is assumed underestimated. Furthermore, the distribution of moisture gradients, which are related to the crack depth development, are analyzed for Austria, demonstrating the influence of mountain areas in the moisture gradient development.