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Numerous studies rely on long-term PM2.5 speciation data from the EPA's Chemical Speciation Network (CSN), for example, to estimate health impacts or investigate the sources and transport of PM2.5 pollution. These studies rely on consistent, long-term time series measurements of PM2.5 species to draw conclusions about PM2.5 emissions sources and their health impacts. However, changes in contractors and associated methodological changes in 2015 and 2018 led to disruptions in the consistency of the CSN data, specifically, concentration discontinuities in the CSN time series for ions and elemental carbon (EC) from November 2015 to September 2018 and from October 2018 onward, respectively. To address the impact of these changes on downstream air quality and health analyses, this study developed correction factors by comparing collocated CSN measurements to measurements from the Interagency Monitoring of Protected Visual Environment (IMPROVE) network, which used consistent instrumentation and contractors throughout the study period. These correction factors reduced the discontinuities in the ions and EC concentration time series data, which could be critical for time series source apportionment receptor modeling, air pollution policy and accountability investigations, and health effect studies. Copyright © 2024 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

Mineral dust from the Sahara desert can travel long distances at high altitudes, perturbing the energy budget of the atmosphere. Charging of dust has been observed to occur near the surface through triboelectric charging during dust lofting, potentially affecting particle coagulation, fall speeds, and the lofting process itself. Apart from near-surface studies, measurements at elevated dust layers, where charge may play a role in particle long-range transport, are rare. This study presents new observations from an uncrewed aircraft system (UAS) of type MASC-3, through an elevated Saharan dust layer over Cyprus on 6 April 2022. The dust layer ranged from 1500 to 2500 meters above sea level (a.s.l), with maximum particle number concentrations (PNC) of 80–100 cm − 3 , primarily consisting of particles up to 2.5 µm in size. Measurements showed elevated charge within the dust layer, with magnitude proportional to PNC. It was concluded that there was a small influence of aircraft charge on the measurements, which was handled by developing a PNC-based correction factor. Corrected charge within the dust layer ranged from 0.2 to 3 pC m − 3 , with most of the charge at the upper and lower dust layer boundaries. The magnitude and location of the charge was consistent with predictions of ion-particle attachment. This suggests that most of the measured charge did not originate from the lofting process, but dust particles were charged on site through ion-particle attachment processes. [ABSTRACT FROM AUTHOR]

Stroboscopic nutation has proved to be invaluable for pulse width calibration (P. S. C. Wu and G. Otting, Rapid pulse length determination in high-resolution NMR, J. Magn. Reson.2005, 176, 115–119), though it is not without its issues. Herein it is proposed that a correction factor be applied to correct for the inaccuracy of the method which is dependent on the NMR system including the probe, observed nucleus, sample type set (solvent, concentration, ionic strength, etc.), temperature, etc. Poor performance of the stroboscopic nutation experiment was also found to be a harbinger of a serious hardware problem. [ABSTRACT FROM AUTHOR]

AbstractThin-walled tubes are commonly used as crucial structures for energy absorption. It is an efficient and convenient research method to establish a small-scale model of the energy-absorbing thin-walled tube for experiments. However, due to the inevitable difference between the design velocity of the test and the actual velocity of the test, it cannot meet the traditional similarity theory. Because of this limitation, this article constructs a similarity design method for the velocity distortion of the multi-cell energy-absorbing tube at the front end of the train under axial impact. Firstly, according to the motion equation of the train system, the design criterion of the similar model under the velocity distortion is derived. Then, the collision mass correction factor is derived based on the elastic-plastic structural energy equation, aiming at the error of the collision peak force and the error of the collision time, the correction factor of the wall thickness of the energy absorbing tube is obtained based on the simulation analysis results. Finally, it is verified that the velocity distortion similarity model can accurately predict the dynamic response of the prototype, and reveals the influence of the mass and wall thickness correction factors on the error. [ABSTRACT FROM AUTHOR]

This paper derives a general Bartlett correction formula to improve the inference based on the likelihood ratio test in a multivariate model under a quite general parameterization, where the mean vector and the variance-covariance matrix can share the same vector of parameters. This approach includes a number of models as special cases such as non-linear regression models, errors-in-variables models, mixed-effects models with non-linear fixed effects, and mixtures of the previous models. We also employ the Skovgaard adjustment to the likelihood ratio statistic in this class of multivariate models and derive a general expression of the correction factor based on Skovgaard approach. Monte Carlo simulation experiments are carried out to verify the performance of the improved tests, and the numerical results confirm that the modified tests are more reliable than the usual likelihood ratio test. Applications to real data are also presented for illustrative purposes. [ABSTRACT FROM AUTHOR]

This article presents the findings of a systematic literature review focusing on the impact of interferences in host materials on Respirable Crystalline Silica (RCS) measurement, and the development of a validated method of calibration for RCS instrumentation for in-field use. The impact of interferences in host materials on RCS measurement has been shown to be critical information required for in-field use of portable RCS devices. Portable RCS instruments such as FTIR and XRD have been established to have good sensitivity for measurement but relatively low specificity due to interference in host materials. It has been shown that correction factors are needed to be applied to account for known interferences, especially when calibrating portable RCS instrumentation in-field. The potential to obtain reliable and repeatable results from RCS analysis instrumentation has also been demonstrated. There was significant evidence that interference materials could be present in host materials, and they influence RCS measurement. There is the potential and possibility of using portable RCS instrument for in-field measurement however the challenge is the calibration of such instrumentation in the field to account for changing host materials and thus potential interferences. [ABSTRACT FROM AUTHOR]

In the present work, a novel refined three-variable quasi-3D shear deformation theory incorporates a correction factor is developed to analyze the buckling behavior of multi-directional functionally graded (FG) curved beams. The proposed displacement field is formulated in accordance with the Euler-Bernoulli beam theory. The research investigated two types of coated Functionally Graded (FG) nanobeams: Hardcore (HC) FG curved nanobeams and Softcore (SC) FG curved nanobeams. Three different material distributions are taken into consideration: a bidirectional material distribution referred to as "2D-FG," a unidirectional transverse material distribution known as "T-FG," and a unidirectional axial material distribution called "A-FG." Eringen's nonlocal elasticity theory is employed to capture small-scale effects. The total potential energy principle is utilized to derive the equilibrium equations of curved nanobeams. A novel solution, utilizing Galerkin's method, has been developed to effectively address a range of boundary conditions. The curved FG beam is supported by an elastic foundation following the Winkler/Pasternak/Kerr model. A comprehensive analysis has been conducted to examine the impacts of various FG schemes, curved beam geometry, nonlocal parameter, elastic foundations, and various boundary conditions on the dimensionless critical buckling loads. This analysis aims to provide a comprehensive understanding of how each of these factors influences the critical buckling loads of the nanobeams. [ABSTRACT FROM AUTHOR]

The Kumaraswamy distribution is doubly limited, continuous, very flexible, and is widely applied in hydrology and related areas. Recently, several families of distributions based on this distribution have emerged. To make a contribution regarding some asymptotic aspects related to the inferential analysis, we derived an analytic expression of order n − 1 / 2 , where n is the sample size, for the skewness coefficient of the distribution of the maximum likelihood estimators of the parameters of the Kumaraswamy distribution. A simulation study and an application are presented to illustrate that, when the sample size is small, the likelihood inferences may not be reliable. We also obtain Bartlett correction factors for the likelihood ratio statistic as well as the results of the bootstrap likelihood ratio test and bootstrap Bartlett correction and present a Monte Carlo simulation study to compare the rejection rates of the tests in question. [ABSTRACT FROM AUTHOR]

This study presents correction factors for the Norwegian fatigue load model for railway bridges. The fundamental idea of a correction factor is to ensure that the load model induces the same fatigue damage as actual traffic. Load measurements from traffic on a representative line on the Norwegian railway network are used to propose correction factors for improved fatigue life estimation with freight and passenger trains. Correction factors improve the accuracy of the estimated fatigue life and reduce the conservatism of the load model. The validity and conservatism of the most damaging train assumption for fatigue load modeling is also considered. The suitability and consequences of using the proposed correction factors for other lines and historic traffic are discussed. [ABSTRACT FROM AUTHOR]

This paper developed a method for more accurate permittivity extraction of high-loss materials using the waveguide method to reduce the effect of the air gap. This method improves the Baker-Jarvis algorithm. It makes the errors of S-parameters caused by the air gap compensated by a correction factor β of the form: (S21 + S12) + β(S11 + S22). In our study, the correction results of β for materials on different frequencies and air gap sizes are quantitatively investigated. Furthermore, we propose a method to obtain an optimal frequency-independent β for different materials. A typical high-loss BeO-SiC ceramic commonly used in vacuum electron tubes is analyzed and discussed in detail. It shows that compared to traditionally utilizing only S21 (β = 0), adopting an optimal β can reduce the average errors of the complex permittivity from 17.7% to 7.9% with a 0.10 mm air gap. The proposed method is verified by measurements of unshaved and shaved samples. [ABSTRACT FROM AUTHOR]

The API p-y method is widely used in the design of offshore wind turbines (OWTs) monopiles at present. This study systematically evaluates the model uncertainty of the p-y method for OWT monopiles and proposes a two-stage calibration approach for evaluating the model bias factor. To overcome the difficulty of limited field tests, a high-fidelity base model is employed as a bridge between the field test data to the p-y method. The field test data is used to calibrate the base model and determine the model error of the base model. Synthetic numerical cases are subsequently generated using the base model to evaluate the correction factor of the p-y method. By combining the model error of the base model and the correction factor of the p-y method, the model bias factor of the p-y method can be evaluated. The reliability analysis of the monopile in an offshore wind project in China is taken as an example. The results serve as a valuable tool for correcting the lateral bearing capacity of OWT monopiles based on the specific soil conditions and risk preferences for the offshore wind turbine project. [ABSTRACT FROM AUTHOR]

In this study, the pore structure and gas permeability of river sand concrete and manufactured sand concrete (mixed with various stone powders) are examined under dry and wet conditions. First, the pore structure of concrete was tested using the mercury-in-pressure (MIP), hydrostatic balance (HB), and nuclear magnetic resonance (NMR) methods. Second, the gas permeability of concrete was measured using the quasi-stationary flow method. Finally, a numerical model was developed based on the relationship between the pore structure and gas permeability. The results indicated that the gas permeability of dry concrete has a quadratic linear relationship with the porosity and volumetric characteristic pore size. The pore structure of partially water-saturated concrete can be corrected using a correction factor and the relaxation rate of the dry material. Finally, a random hierarchical bundle model using the HB–NMR method is proposed. The maximum relative deviation between the predicted and experimental values is 48.28%. [ABSTRACT FROM AUTHOR]

This article aims to investigate the buckling and free vibration behaviors of nanocomposite beams reinforced with functionally graded (FG) agglomerated carbon nanotubes (CNTs) in polymeric beams matrix. In order to estimate the material properties of the FG CNTs reinforced beam, the Eshelby–Mori–Tanaka rule on the basis of equivalent fiber is employed. Moreover, the Lagrange's principle is used to achieve the governing equations under supposition of the refined higher order beam theory without need of any shear correction factor. The differential quadrature finite element method (DQFEM) as a robust and precise numerical procedure is utilized to achieve the natural frequencies and buckling loads with various boundary supports. Then, the assessment of the effects of different factors such as of CNTs agglomeration parameters, different patterns of CNTs distribution, length to thickness quotients, and mixed boundary conditions on the vibrational and buckling responses of agglomerated CNTs reinforced beam are explored. It is concluded that the current numerical solution based DQFEM is efficient and accurate for predicting the mechanical behavior of the nanocomposite structures. Moreover, the stability and vibration responses of the NC beams can be significantly affected by tailoring the agglomeration parameters. [ABSTRACT FROM AUTHOR]

Surface tooth wear is one of the major causes of tooth failures in gear drives. Boosting tooth wear resistance is a significant research objective for designing high-quality asymmetric spur gears with longer life against wear. The main goal of the present work is to boost the wear resistance of the asymmetric spur gear by changing the tooth shape through profile modification. The proper distribution of correction factor to the pinion and gear is necessary to enhance the gear performance. The asymmetric spur gear with different values of sum of profile correction factors (−0.2, 0 and 0.2) is chosen to evaluate the wear depth. This sum of correction factors is accurately distributed between the asymmetric pinion and gear for attaining balanced sliding velocity at the tip and root, balanced slide to roll ratio at the tip and root, equal bending strength in the asymmetric drive and maximum balanced wear in the face and flank regions of the pinion. The optimum values of the correction factor of the asymmetric pinion and the maximum tooth wear are evaluated for the above four different balanced cases. The calculated tooth wear is lower in the balanced wear method than that in other balanced methods. [ABSTRACT FROM AUTHOR]

The intrinsic relationship of the thermal stress intensity factor and temperature difference between the upper and lower surface of the crack have been studied in this paper. The results show the thermal stress intensity factor is always proportional to the temperature difference between the upper and lower crack surface, and the ratio depends only on material parameters and crack length, but is independent of loading condition. For a finite medium problem, the above conclusion is still valid by simply adding a size related correction factor. When the size of medium is 10 times larger than the crack size, the size related correction factor is less than 1.019, that is, the error is less than 2%. Our conclusion provides a theoretical basis to estimate the localization thermal stress intensity factor simply by measuring the temperature difference of the crack surface. [ABSTRACT FROM AUTHOR]

AbstractThe laboratory measurement of the acoustic attenuation coefficient of seafloor sediment poses a significant challenge as it is more difficult to measure with the same precision and convenience as the sound velocity. A novel dual-probe acoustic measurement method (DPAMM) addresses this challenge by simultaneously obtaining the sound velocity and acoustic attenuation coefficient of seafloor sediments, enabling stratified measurements with minimal disturbances. However, issues related to the sensitivity difference between the probes, the diameter of the sample pipe, and the inter-probe blockage can affect the accuracy of the measurement. To address these influencing factors, water was used as a reference standard for calibrating DPAMM. Experimental investigations were conducted to examine the effects of factors such as the diameter of the sample pipe, probe spacing, probe distance from the acoustic source, and probe sensitivity differences. The results revealed a positive correlation between the diameter of the sample pipe and the effective measurement distance, as well as the correction factor for probe blockage. Based on the calibration method described above, sensitivity calibration coefficients and blocking correction coefficients were derived from the experiments. The application of the stratified acoustic measurement of seafloor sediment samples demonstrates the effectiveness of the DPAMM. [ABSTRACT FROM AUTHOR]

The anatomical method is considered the most accurate stature estimation method, however, research has concluded that the soft-tissue correction factors associated with this method may be sex- and population-specific. Therefore, this study aimed to evaluate the applicability of these soft-tissue correction factors for the estimation of stature in White South African males. Magnetic resonance imaging scans of 30 White South African male volunteers, between 21 and 59 years of age, were used to collect skeletal measurements of bones that contribute to total skeletal height. The soft-tissue correction factors within the literature were subsequently applied to estimate the living stature of each individual. Paired t-tests were used to compare the accuracies of these estimates of living stature to the measured heights of the participants. Living stature was significantly underestimated using the soft-tissue correction factors of Fully (1956; 6.14 cm), Raxter and colleagues (2006; 4.80 cm), and Brits and colleagues (2017; 0.96 cm), and significantly overestimated by Bidmos and Manger (2012; 9.65 cm). Cloete's (2017) equation overestimated stature by 0.65 cm, however, this was not significant. These results suggest population-specific soft-tissue correction factors associated with stature estimation and, therefore, the newly derived stature estimation equations should be used to estimate stature of White South African males. [ABSTRACT FROM AUTHOR]

This article analyzes the bending behavior of functionally graded sandwich plate structures submitted to sinusoidal loads using the hyperbolic quasi-3D shear deformation plate theory. In this theory, the number of unknowns is reduced from six to only five unknowns using an undefined integral without needing any shear correction factor. Furthermore, the effective constituent material properties of the upper and lower layers of the functionally graded sandwich plate are assumed to vary smoothly and continuously only in the thickness direction. In contrast, the core layer is still homogeneous and isotropic. The governing equilibrium equations of simply supported functionally graded sandwich plates are derived using the principle of virtual displacement. Their analytical solution is obtained using Navier's technique for various schemas of functionally graded sandwich plates. The effects of the power law index, side-to-thickness ratio, and aspect ratio on the bending behavior are investigated. [ABSTRACT FROM AUTHOR]

This paper aims to develop an equivalent circuit model (ECM) for Lithium Iron Phosphate (LFP) batteries as they have a flat voltage profile and dominant hysteresis behavior compared to other lithium-ion chemistries. Hence, it is challenging to deduce an accurate model to predict the performance of the battery. The model introduces a hysteresis correction factor (HCF) calculated from the capacity test and the R and C parameters for charging and discharging through pulse current test. The state of charge is calculated through Coulomb counting, and over the entire range, the terminal voltage of the model coincides with the experimental voltage. The estimated maximum deviation in the voltage for the existing 2RC model is 45 mV during discharging with a constant C-rate, and for the proposed model, the maximum deviation in the voltage is found to be 30 and 20 mV during discharging and charging, respectively. Further, to increase the accuracy in the estimated voltage, a 3RC model with HCF is found to be the most suitable for LFP batteries. This model reduces the deviation to 10 and 12 mV during discharging and charging, respectively. The performance of the model in MATLAB Simulink is validated with the experimental results through the Dynamic Stress Test (DST) and the Urban Dynamometer Driving Schedule (UDDS). This model reduces the root mean square error (RMSE) in the estimated voltage by 60% under UDDS compared to other existing models. [ABSTRACT FROM AUTHOR]

In this paper, we present a reformulation of Mickens' rules for nonstandard finite difference (NSFD) schemes to adapt them to systems of ODEs. We want to compare several methods within the class of NSFD schemes. These methods are expressed as exponential integrators which treat exactly the linear part of the equations. While the classical methods address each equation of a system separately, we propose here to address them as a whole, which involves a reformulation of Mickens' rules. This leads to enhance the results compared to the classical case, even if approximations of the matrix exponentials are used. Precisely, using Cayley–Hamilton theorem we obtain two correction factors, one of which is linked to the size of the system and the other to the nonlinear term, we are thus able to use test cases which show the impact of one or another corrector. We prove the consistency and the zero-stability of the method in the nonlinear case to conclude to the convergence of the method. [ABSTRACT FROM AUTHOR]

In this study, a new mixed-field zigzag shell model is proposed in terms of Reissner's Mixed Variational Theorem (RMVT) for the composite laminates with curvature. In this model, refined zigzag theory (RZT) is employed to improve the accuracy and efficiency by introducing through-the-thickness piecewise linear warping functions. Moreover, the shear correction factors are eliminated. It is also different from the published models for composite laminated shells, the continuity conditions of interlaminar transverse shear stresses (TSSs) are satisfied a priori based on RMVT. The equilibrium equations and related boundary conditions are also derived from RMVT. Subsequently, the static performance, natural frequencies, and critical loads of composite laminates with curvature are verified by comparing them with the 3D elastic solutions and other existing ones. It is observed that the present model accounts for not only the efficiency of the low-order models but also the accuracy of the high-order models. Finally, it is shown that the ply stacking, side-to-thickness ratios, and side-to-radius ratios play an important role in percentage errors between the present model and the previous ones. [ABSTRACT FROM AUTHOR]

Potential health concerns from cooking with natural gas appliances include short-term exposure to nitrogen dioxide (NO2). Published, one-hour concentrations measured in a few kitchens during simulated cooking events have been cited as justification for moving to electric alternatives by certain advocates. These estimates, however, are not believed to adequately represent typical potential exposure concentrations. In this paper, the various challenges in evaluating potential exposures based on measured indoor air concentrations of NO2 associated with cooking are identified and discussed. These include the lack of standards for indoor air in the U.S., the relatively short duration of cooking activities, and the likelihood of bias in indoor NO2 measurements due to the instrument response to other nitrogen-containing compounds. Correction factors for making more meaningful comparisons are suggested, including correction for duration of cooking time and correction for presence of nitrous acid (HONO). [ABSTRACT FROM AUTHOR]

In Part I of this series, the variants of the Reynolds number, Prandtl number, and the reference temperature used for Nusselt number correlation are categorized and deliberated. These are the principal dimensionless variables that appear in the majority of Nusselt number correlations. Part II of this series (this part) thereby scrutinized and elucidated the origins and properties of variants of correction factors and buoyancy-related dimensionless variables. The correction factors consist of the ratio of cross-sectional wall-to-bulk properties, including density, dynamic viscosity, thermal conductivity, isobaric specific heat, and Prandtl number. When a significant cross-sectional temperature difference is anticipated which may result in localized laminarization, they are pertinent for modeling these rather unique heat transfer phenomena. The buoyancy-related dimensionless variables include the variants of the Grashof number, the ratio of the Grashof number, and the buoyancy parameter. They can be used to identify if the buoyancy effect is significant enough to affect the Nusselt number, as well as to predict the onset of Deteriorated Heat Transfer, which can be caused by buoyancy- and acceleration-induced laminarization. Tables for recently published review articles, books, and reports are provided to facilitate the consolidation of relevant fields. [ABSTRACT FROM AUTHOR]

This article intends to investigate the free vibration damping characteristics of functionally graded viscoelastic nanobeams embedded in viscoelastic foundations using the infinite Kelvin–Voigt model of the Winkler–Pasternak type. This model is based on the nonlocal strain-driven gradient elasticity theory of Eringen. A power law model is then adopted to describe the continuous variation in the material properties of functionally graded material nanobeams. The study was carried by means of the first-order shear deformation theory with the shear correction factor using the finite element method. For the purpose of validating the developed model, it was decided to compare the results obtained with those reported about elastic nanobeams in the literature. Moreover, the influence of the power law exponent, structural damping coefficient, foundation coefficient, nonlocal parameter, and boundary conditions on the free frequency response of viscoelastic nanobeams was also investigated. [ABSTRACT FROM AUTHOR]

Accurate measurements of particle diameter are necessary for quantitative characterization of key aerosol properties including the Cunningham slip correction factor, charging probability, diffusion coefficient, coagulation coefficient, and optical properties. In this study, we use four techniques to measure the diameter of nominal 100 nm reference spheres having a distributional standard deviation of less than 2 nm. The instruments used are a differential mobility analyzer (DMA), atomic force microscopy (AFM), scanning electron microscopy (SEM), and an electrical-gravitational aerosol balance (EAB). All four measurements are traceable to SI units at National Institute of Standards and Technology (NIST) or at National Institute of Advanced Industrial Science and Technology (AIST). This study includes quantitative estimates of the measurement uncertainty for each technique. It finds that the measured average particle diameter is within 3% for all the methods, with at least some overlap in all the estimated uncertainties using a 95% confidence interval. Nevertheless, the difference between the EAB results and the other methods may become significant as they are separately intended to be used in the manner described here for the traceable certification of future nanoscale particle size standards. Possible reasons for the differences are incorrect or inadequate accounting for surface residue for aerosol measurements, adhesion-force distortion for the AFM measurements, e-beam shrinkage for the SEM measurements, slip correction uncertainty for the DMA, and work function variability of the electrodes for the EAB. [ABSTRACT FROM AUTHOR]

The post-buckling behavior of a hybrid functionally graded (FG) rectangular plate reinforced with carbon nanotubes (CNT) is presented. The mathematical model developed based on transverse displacement variation of second-order in third-order shear deformation theory, hence referred to as modified third-order shear deformation theory (MTSDT). Transverse shear stress is imposed zero on top and bottom surface of plate. 2D C0 finite element (FE) formulation model developed based on MTSDT. Inhouse MATLAB code developed of present FE formulation. The rectangular plates consist of matrix material, fiber, and CNT as reinforcement material. The grading of fiber material in the thickness direction ensured using a power–law distribution. The material characteristics of the hybrid FG plates predicted using the Halpin-Tsai equation and the rule of mixing technique. No shear correction factor is required due to realistic parabolic behavior considered in the present work. The comparison study results of the present model are in good agreement with the published work. After confirming the accuracy of the present model a parametric study was carried outd to check the influence of different parameters. [ABSTRACT FROM AUTHOR]

This is the first study of the static bending and free vibration response of organic nanoplates based on the combination of nonlocal theory with various shear strain theories, where the theory of shear deformation of the plate has the advantage of requiring no shear correction factor. The equilibrium equation of the plate is derived using Hamilton's principle, the analytic solution is derived using the Navier solution form, and the finite element technique is implemented using a quadrilateral element with four nodes and six degrees of freedom for each node. Moreover, this is the first work to calculate for nanoplates with a nonlocal parameter whose value varies with plate thickness. This study's credibility has been established by comparing it to previously published findings, which are utilized to validate the results of analytical and numerical calculations, respectively. In addition, the study investigates how a range of components impact the displacement and stress response of organic nanoplates. The findings of the study indicate that there are some circumstances in which it is not feasible to disregard the nonlocal parameter while doing calculations for organic nanostructures. [ABSTRACT FROM AUTHOR]

In this present study, we are interested in the use of a precise theory of shear deformation for the buckling analysis of plates with functional gradation simply supported such as the refined theory of plates with four variables. Several parameters of comparison have been used, dimensional and nondimensional. The displacement field is compatible with this study, the nonuse of shear correction factors is satisfied, and the choice of material is very precise in such a way are variable according to the thickness of the plate and on the other hand to make comparison with other researcher and confirms that this study gives precise results and converges. The transverse shear stresses vary through the thickness, the results found is also studied and discussed. [ABSTRACT FROM AUTHOR]

This article presents a numerical method for analyzing the compressive buckling of porous power-law functionally graded (PPFG) plates placed on Pasternak foundations, which is based on a novel refined quasi-3-dimensional hyperbolic shear deformation theory (RQHSDT) combined with the Navier solution technique. The RQHSDT employs a novel hyperbolic distribution of in-plane displacements through the plate thickness to account for non-linear variations in transverse shear stresses, satisfies the traction free boundary conditions on the top and bottom surfaces, and accounts for shear deformation and thickness stretching effects of the plates without the use of any shear correction factors. Unlike classical shear and normal deformation theories, the RQHSDT has only four variables in its displacement field, as opposed to five or more variables in other quasi-3D shear deformation theories, which reduces the number of unknown variables and governing equations in plate analyses and simplifies calculations. The governing equations of the buckling problem are derived using the virtual work principle. In problem solving, the Navier solution technique is used to obtain the exact solutions for the rectangular PPFG plates with simply supported edges subjected to in-plane loading. The accuracy of the proposed approach is confirmed by comparing the obtained results to those of previously published quasi-3D shear deformation theories. Using comprehensive parametric studies, the effects of gradient index, porosity fraction index, porosity distribution type, geometric parameters, two-direction compression ratio, and stiffness of foundation parameters on buckling of PPFG plates are investigated. [ABSTRACT FROM AUTHOR]

The static deflection of plates made from functionally graded materials integrating nanoparticles and porosities is analyzed. The models developed, consider equivalent single layer and layerwise approaches jointly with different shear deformation theories, and were implemented via finite element method. For the first-order shear deformation models, the shear correction factor is determined for each case. The models' performances were verified and several case studies were considered to analyze the influence of parameters such as material properties, nanoparticles presence, and layers' porosities distributions in the plates' deflection. The results enable understanding the influence of design parameters as the models' prediction trends. [ABSTRACT FROM AUTHOR]

Employing Expanded PolyStyrene, EPS has become common in the construction industry, however, their compressibility creates complexities in effective stress analysis. In this paper, the compressibility of EPS beads and the overall compressibility of sand–EPS beads mixtures have been evaluated. Drained and undrained one-dimensional compression tests along with CD and CU triaxial tests were performed on the mixtures to evaluate the classic effective stress equation. Modified versions of the effective stress equation were applied to results and pore pressure correction factors were obtained from both data series based on two different effective stress analysis approaches (volume change and shear strength related) and compared. Results showed that the two sets of correction factors are consistent. Therefore, correction factors obtained based on the compressibility parameters of the mixtures can be used in the effective stress analysis of CU triaxial tests. Pore pressure factors obtained from the oedometer data were used to analyze results of CU triaxial tests. It is shown that a better agreement between CD and CU stress path results is obtained when the EPS compressibility is considered, leading to similar effective strength parameters in both conditions. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study is to develop the Turkish version of hearing in noise test for children (HINT-C) by providing norms and correction factors for the children in different age groups. Methods: A total of 77 individuals with normal hearing – 62 children (6–12 years old) and 15 adults (18–30 years old) – were included. Twelve phonemically balanced 10-sentence lists were created from the adult version of the Turkish HINT (Study 1). Age-specific norms, correction factors and maturation effects were examined using the Turkish HINT-C (Study 2). Results: Mean performances under different listening conditions and Spatial Release from Masking (SRM) advantage values were obtained for the 6-, 8-, 10-, and 12-year-old and estimated for the 7-, 9-, and 11-year-old age groups, and correction factors were calculated for all children age groups. Turkish-speaking children did not achieve adult-like hearing in noise performance, until they were 12 years old. Conclusions: Twelve phonemically balanced 10-sentence lists of Turkish HINT-C were created, and the mean performances of children in different age groups were measured. In addition to the age-specific HINT-C norms and correction factors for the 6-, 8-, 10-, and 12-year-old age groups, the maturation effects were determined. Highlights The assessment of speech-in-noise perception is highly critical for children. To evaluate the speech-in-noise perception ability, 12 phonemically balanced 10-sentence lists of Turkish HINT-C were created. Speech-in-noise perception ability improves with age. Turkish-speaking children do not achieve adult-like hearing in noise performance, until they were 12 years old. [ABSTRACT FROM AUTHOR]

In this paper, we obtain the Bartlett-type correction factor for the gradient test statistic in heteroskedastic generalized linear models (HGLMs). We present an extensive Monte Carlo study to evaluate the performance of the corrected gradient test in small sample sizes. We also compare its performance with the usual gradient, likelihood ratio (LR), score, Wald, improved LR and improved score statistics along with bootstrap tests. [ABSTRACT FROM AUTHOR]

The Source Jerk Integral (SJI) method has been extensively used to determine the subcriticality in VENUS-F zero-power experiments since 2012. The obtained results were in the range from −5 $ to about −20 $ and concerned the subcriticalities of accelerator-driven system MYRRHA mockup cores. Within the SALMON program, which is dedicated to the safe loading procedure of pressurized power reactors, five subcritical core configurations were assembled and studied in the VENUS-F reactor in 2019. These cores simulated the loading process in inverse mode: from more reactive to deep subcritical. The subcriticality of five variants of the SC11 VENUS-F core was changed in steps from −20 $ to about −100 $ by replacing the fuel assemblies with lead reflector assemblies. The subcriticality levels were determined with the pulsed neutron source (PNS) and SJI methods. The GENEPI-3C deuterium accelerator coupled with VENUS-F was used as an external neutron source. The results of the measurements obtained with the SJI method are presented in this paper. Time-dependent Monte Carlo calculations were performed to simulate the SJI experiments and to determine spatial-energy correction factors. Static Monte Carlo simulations were performed to calculate neutron spectra and reactivity. The results of the measurements (both SJI and PNS) are compared with the static MCNP calculations. [ABSTRACT FROM AUTHOR]

The popularity and widespread of electronic cigarettes (ECIGs) have warranted a necessity for monitoring different populations directly or indirectly exposed to particulate matter (PM) from ECIGs. To accurately estimate exposure to aerosols from ECIGs, it is important to correctly measure the concentration of aerosols. Real-time aerosol monitors are usually based on optics that provides biased measurements that are adjusted using filter correction factors. In addition, low-cost aerosol sensors have become popular that allow widespread of these sensors and can estimate ECIG aerosol exposure after calibration. Therefore, this study determined the filter correction factors for three aerosol monitors (MiniWRAS, pDR, and SidePak) based on exposure to six ECIG brands and two particle sizes (PM1 and PM2.5). In addition, the GeoAir2 low-cost monitor was evaluated compared to filter corrected MiniWRAS measurements for these exposures. The study also evaluated the real-time measurements and mass median diameter (MMD) for each ECIG brand. The correction factors varied between aerosol monitors, ECIG brands and particle sizes, with ranges for PM2.5 that span between 1.85 and 2.42 (MiniWRAS), 0.50 and 0.58 (pDR), and 0.24 and 0.28 (SidePak). The GeoAir2 underestimated the reference measurements but had a high correlation (r ¼ 0.90 0.94), showing that the monitor can be effectively calibrated to provide good estimates. The real-time average PM2.5 measurements differed between aerosol instruments with concentrations that ranged between 1398 and 3706 lg/m³ (MiniWRAS), 5479 and 16,825 lg/m³ (pDR), and 9783 and 29,808 lg/m³ (SidePak). Finally, the MMD values spanned between 0.45 and 0.80 lm based on the MiniWRAS measurements. The differences between the raw real-time measurements for the aerosol monitors show the necessity for developing filter correction factors to accurately measure ECIG exposure. [ABSTRACT FROM AUTHOR]

In this study, a simple polynomial bias correction method is developed to correct the bias in the forecasted streamflow (runoff) derived from a global circulation model (GCM). First, a set of polynomial correction factors was derived comparing observed and GCM-derived runoff for a hindcast period (1961–2000) for each of the 11 selected GCMs. The correction factors are used to correct the GCM-derived streamflow for projected periods (2046–2065 and 2081–2100) for the Intergovernmental Panel on Climate Change scenarios A2 and B1 (CMIP3) for the Murray-Hotham catchment of Western Australia. The assumption is that the correction factors derived for each GCM for the observed period (1961–2000) are valid for the projected periods. Results show the method reduces biases considerably for the projected runoff at a catchment scale. The method developed here uses CMIP3 data but it may be applicable to any GCM data, such as CMIP5/CMIP6. [ABSTRACT FROM AUTHOR]

The current work presents the combination of isogeometric approach (IGA) and Carrera unified formulation (CUF) to perform the buckling analysis of isotropic thin-walled and orthotropic beams. Toward this end, the layerwise (LW) theory based CUF and B-spline basis functions in IGA have been used. The LW theory uses Lagrangian expansion (LE) to estimate the displacement field in the cross-section. However, in the present study, B-spline basis functions in both longitudinal direction and cross-section have substituted the corresponding functions. The CUF expresses the 3 D displacement fields as a set of 1 D generalized unknown displacement. Combined model in the present study obliterates the costly use of 3 D finite element analysis with its high accuracy and loyalty to 3 D problems. The principle of virtual displacement (PVD) is used to obtain the fundamental nuclei. One of the features of CUF is that it's higher-order expansion is free of the Poisson locking phenomenon. Also, there is no need to use the shear correction factor. Some examples of the isogeometric analysis of laminated composite beams with different geometries and boundary conditions are conducted and comparison of the critical buckling load results illustrate the proper validation and formulation of the present study. [ABSTRACT FROM AUTHOR]

In this study, vibration response of functionally graded plate resting on a viscoelastic foundation is studied. An analytical solution is proposed using a high-order shear deformation theory with only four unknowns, which means that the current theory has few unknowns compared to the first and other high shear deformation theories. The present theory uses a displacement field with integer terms instead of derivative terms by also including the shear deformation effect without introducing the shear correction factors. The mathematical model of the foundation used followed the Winkler–Pasternak two-coefficient model, with an additional term added to represent the damping effect. The governing equations were generated using the principle of virtual works. Subsequently, the analytical solution is based on Navier's principle to solve the vibration problem of a simply supported FG plate resting on a viscoelastic foundation. Some numerical results are presented to demonstrate the impact of the material index, the type of elastic foundation and the damping coefficient of the foundation on the dynamic response of FG plates resting on viscoelastic foundations. In the end, it is concluded that the current results with the proposed theory are found to be in good agreement with the other available results and this theory can easily be used to solve the free vibration problems of FGM plates resting on visco-Pasternak medium. [ABSTRACT FROM AUTHOR]

In this study, the instantaneous collection efficiency and pressure drop of an N95 facemask is numerically simulated in a setting similar (but not identical) to that used by NIOSH to certify N95 respirators. More specifically, a CPU-friendly macroscale model is developed, for the first time, to simulate the performance of an electrostatically-charged facemask when the mask is clean and when it is loaded with neutral or neutralized nanoparticles. The simulations were performed using ANSYS software enhanced with in-house subroutines, and they were calibrated using the experimental data reported in the literature for the initial efficiency of N95 masks. In addition, a correction factor was developed for the Kozeny-Carman permeability equation to expand its application to the case of nanoparticle-deposits, where the dendrites porosity is very high and the aerodynamic slip is expected to occur. Copyright © 2023 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

A temperature correction model for Falling Weight Deflectometer (FWD) backcalculated dynamic modulus was developed and validated in this study. FWD test was conducted to determine the field dynamic modulus, while the indirect tensile (IDT) dynamic modulus test was used to measure laboratory dynamic modulus. A temperature correction model was developed considering the effect of FWD loading frequency and pavement temperature. It was validated using field FWD data obtained from 26 Westrack pavement sections and Korean national highways' long-term pavement performance database. Also, the correction factor was compared with similar existing models using FWD testing in the field. It was observed from study results that the temperature correction model is capable of predicting the dynamic modulus accurately. [ABSTRACT FROM AUTHOR]

Stable carbon (δ13C) and nitrogen (δ15N) isotopic compositions of bone and dentine collagen extracted from museum specimens have been widely used to study the paleoecology of past populations. Due to possible systematic differences in stable isotope values between bone and dentine, dentine values need to be transformed into bone-collagen equivalent using a correction factor to allow comparisons between the two collagen sources. Here, we provide correction factors to transform dentine δ13C and δ15N values into bone-collagen equivalent for two toothed whales: narwhal and beluga. We sampled bone and dentine from the skulls of 11 narwhals and 26 belugas. In narwhals, dentine was sampled from tusk and embedded tooth; in belugas, dentine was sampled from tooth. δ13C and δ15N were measured, and intra-individual bone and dentine isotopic compositions were used to calculate correction factors for each species. We detected differences in δ13C and δ15N. In both narwhals and belugas, we found lower average δ13C and δ15N in bone compared with dentine. The correction factors provided by the study enable the combined analysis of stable isotope data from bone and dentine in these species. [ABSTRACT FROM AUTHOR]

The automated grain sizing technique (AGS) has been widely used to characterize grain size distribution of a channel bed. A handful number of literatures have been made available in portraying the wide range of AGS application for river and coastal studies. However, the accuracy of this technique is subject to further validation and verification. The accuracy of the AGS technique is lessened due to distortions of image, relief, or tilt. This paper discusses the consistency of the AGS technique at different ground sampling distances, and the implementation of correction factors to modify the grain size distribution (GSD) curve of the AGS technique on fine and coarse fractions. Through a discrepancy ratio test, the GSD curve from the AGS technique was compared with those of the conventional sieving and pebble-counting methods. It was observed that relief distortion did not have a significant impact on the GSD curve. However, textural presence in sediment particles led to 'over-segmentation,' which complicated the edge detection of an individual particle. The introduction of correction factors, using least square regression equation, was able to correct those errors by reducing and maintaining the discrepancy ratio to 0.688–1.283 for fine fractions, and 0.758–1.125 for coarse fractions. [ABSTRACT FROM AUTHOR]

In the current work, a four-node rectangular finite element with assumed natural shear strains, based on the exact neutral surface position and new higher-order shear deformation theory is employed to perform mechanical buckling and free vibration analysis of functionally graded plates. The present theory has only five unknowns and satisfies zero transverse shear stress at the top and bottom surfaces of the plate, therefore a shear correction factor is not necessary. The accuracy of the proposed formulation is evaluated by comparing the obtained results with those available in the literature. [ABSTRACT FROM AUTHOR]

Three types of representative unit cell (RUC) of [±θ/904]S composite laminates and cracked plies were created to obtain the constitutive model of the cracked plies and to compare their accuracy of the calculation. The RUCs represent the damaged laminates, cracked plies, and cracked plies with additional constraints. A correction factor was defined to improve the accuracy of transverse modulus estimation using the RUC of cracked plies with constraints. The correction factor and numerical results were discussed to illustrate the constraint effect of the adjacent plies on the cracked plies in terms of stiffness, orientation, and thickness. [ABSTRACT FROM AUTHOR]

The extension of high-speed railway construction to earthquake-prone regions has significantly increased the probability of trains encountering an earthquake while running on a bridge. Therefore, it is urgent to explore the applicability of the additional static quality method (ASQM) of train load simulation specified in the Code for seismic design of railway engineering. Based on comprehensively considering the uncertainty of ground motions, this paper builds spatial analysis models for train–track–bridge systems based on ASQM and the moving spring-mass column method (MSMCM), respectively. Next, it calculates the seismic responses of structures under near-fault earthquakes using a large number of samples and evaluates the applicability of ASQM through large-sample analysis. As the analysis results revealed, the statistical characteristics of over-standard ratios tend to stabilize with the increase of sample size. Under near-fault earthquakes, bearing deformation, pier shear strength, and maximum ductility all have high over-standard ratios. The seismic checking computations of bridge structures based on ASQM have failed to meet the applicability requirements, and the calculation results of the seismic responses of track structures are severely distorted. Introducing a reasonable dynamic response correction factor based on ASQM helps to effectively lower over-standard ratios, thus meeting the applicability requirements for the seismic checking computations of bridges. [ABSTRACT FROM AUTHOR]

The new composite functionally classified materials (FGM) used in plates contain probably a porosity volume fraction which needs taking into account this aspect of imperfection in the thermo-mechanical behavior of such structures. A refined shear deformation theory is developed to investigate the thermo-mechanical bending response of porous advanced composite plates such as functionally graded plates by using Navier solution. This work presents a model that employed a new transverse shear function by decomposing the transverse displacements into two parts, the bending part and shear part, the simplified refined shear deformation theory has less unknowns than the first-order shear deformation theory, the higher-order shear deformation theory, the sinusoidal shear deformation theory and the quasi-3D theory, so its computational expenses are reduced. In addition, the new refined theory needs no shear correction factor. The comparisons of deflection, axial stresses, and transverse shear stresses of the porous FGM plates obtained by the proposed theory, these results are compared with others in the literature. [ABSTRACT FROM AUTHOR]

Bictegravir (BIC) is a potent small-molecule integrase strand-transfer inhibitor (INSTI) and a component of Biktarvy®, a single-tablet combination regimen that is currently approved for the treatment of human immunodeficiency virus type 1 (HIV-1) infection. The in vitro properties, pharmacokinetics (PK), and drug-drug interaction (DDI) profile of BIC were characterised in vitro and in vivo. BIC is a weakly acidic, ionisable, lipophilic, highly plasma protein-bound BCS class 2 molecule, which makes it difficult to predict human PK using standard methods. Its systemic plasma clearance is low, and the volume of distribution is approximately the volume of extracellular water in nonclinical species. BIC metabolism is predominantly mediated by cytochrome P450 enzyme (CYP) 3A and UDP-glucuronosyltransferase 1A1. BIC shows a low potential to perpetrate clinically meaningful DDIs via known drug metabolising enzymes or transporters. The human PK of BIC was predicted using a combination of bioavailability and volume of distribution scaled from nonclinical species and a modified in vitro-in vivo correlation (IVIVC) correction for clearance. Phase 1 studies in healthy subjects largely bore out the prediction and supported the methods used. The approach presented herein could be useful for other drug molecules where standard projections are not sufficiently accurate. [ABSTRACT FROM AUTHOR]

Experiments were performed for local scour at a complex pier with two inclined, rectangular columns footed on a group of circular piles with a pile cap. The research fills a gap in existing literature, where studies for complex piers have considered a single, vertical column. The laboratory campaign involved the variation of the pile diameter and arrangement, and of the cap thickness and elevation above the non-scoured bed. The results of carefully conducted scour runs revealed the cap elevation as a most influential parameter. In cases of buried and partially buried pile cap, in fact, the cap acted as a scour countermeasure. For high cap elevation, the supporting piles were also exposed to the flow and their size influenced the resulting scour depth values as it directly impacted on the pier frontal area. The measured scour depth was compared to the values predicted by several literature methods for complex piers with a vertical column, supporting the possibility to extend their use to the geometry investigated in the present study. [ABSTRACT FROM AUTHOR]

An attempt has been made to identify promising sites for tidal stream energy assessment along the Goa coast on central west coast of India. A two-dimensional tidal-driven validated numerical model is used to assess the tidal stream velocities. The numerical model results are further used to estimate the tidal stream energy over the simulation period which would form a resourceful input for future to optimize locations of tidal energy farms. The locations of current maxima in each of the tidal driven regions have been identified and the energy is estimated thereof. This paper describes the tidal driven currents using a numerical model and their validation with measurements; and estimation of tidal stream energy among the different selected locations to choose the most feasible location for tidal energy extraction along Goa coast. [ABSTRACT FROM AUTHOR]