Longitudinal Research Articles

New findings on clinical experience on surface-guided radiotherapy for frameless non-coplanar stereotactic radiosurgery treatments.

The aim of this study was to assess the accuracy of a surface-guided radiotherapy (SGRT) system for setup and intra-fraction motion control in frameless non-coplanar stereotactic radiosurgery (fSRS) using actual patient data immobilized with two different types of open-faced masks and employing a novel SGRT systems settings. Forty-four SRS patients were immobilized with two types of open-faced masks. Sixty lesions were treated, involving the analysis of 68 cone-beam scans (CBCT), 157 megavoltage (MV) images, and 521 SGRT monitoring sessions. The average SGRT translations/rotations and 3D vectors (MAG-Trasl and MAG-Rot) were compared with CBCT or antero-posterior MV images for 0° table or non-coplanar beams, respectively. The intrafraction control was evaluated based on the average shifts obtained from each monitoring session. To assess the association between the SGRT system and the CBCT, the two types of masks and the 3D vectors, a generalized estimating equations (GEE) regression analysis was performed. The Wilcoxon singed-rank test for paired samples was performed to detect differences in couch rotation with longitudinal (LNG) and lateral (LAT) translations and/or yaw. The average SGRT corrections were smaller than those detected by CBCT (≤0.5mm and 0.1°), with largest differences in LNG and yaw. The GEE analysis indicated that the average MAG-Trasl, obtained by the SGRT system, was not statistically different (p=0.09) for both mask types, while, the MAG-Rot was different (p=0.01). For non-coplanar beams, the Wilcoxon singed-rank test demonstrated no significantly differences for the corrections (LNG, LAT, and yaw) for any table rotation except for LNG corrections at 65° (p=0.04) and 75° (p=0.03) table angle position; LAT shifts at 65° (p=0.03) and 270° (p<0.001) table angle position, and yaw rotation at 30° (p=0.02) table angle position. The average intrafraction motion was<0.1mm and 0.1° for any table angle. The SGRT system used, along with the novel workflow performed, can achieve the setup and intra-fraction motion control accuracy required to perform non-coplanar fSRS treatments. Both masks ensure the accuracy required for fSRS while providing a suitable surface for monitoring.

Improving Cardiovascular Disease Forecasting with Machine Learning and Electronic Medical Record Data Characteristics Within a Local Healthcare Network

The PCE Risk Calculator, developed by the ACC/AHA, is frequently utilized in the United States for the purpose of averting the onset of Atherosclerotic cardiovascular disease (ASCVD) via first-line defense strategies. However, this calculator may not accurately estimate risk for certain populations, potentially leading to either under- or over-estimation of risk. We have created calculator for ASCVD risk specific to a population by leveraging advanced Machine Learning (ML) techniques and Electronic Medical Record (EMR) data. Our study involved comparing predictive accuracy of our calculator with PCE calculator. Between January 1, 2009, and April 30, 2020, data was gathered from 101,110 distinct EMRs of patients who were actively receiving treatment. Patient datasets underwent machine learning techniques containing Longitudinal (LT) and Cross-Sectional (CS) features, or solely CS features, derived from laboratory values and vital statistics. The models' effectiveness was assessed using fresh price metric (Screened Cases Percentage @Sensitivity level). In terms of prediction accuracy, every ML model that was tested performed better than the PCE risk calculator. Area Under Curve (AUC) score of 0.902 was obtained by Random Forest (RF) ML technique when CS and LT characteristics were combined (RF-LTC). Our machine learning model only needed to screen 43% of patients in order to identify 90% of positive ASCVD cases, in contrast to the PCE risk calculator, which required screening 69% of patients. Prediction models created using ML techniques reduce the amount number of tests necessary to forecast ASCVD and increase the accuracy of ASCVD prediction when compared to using PCE calculator alone. The combination of LT and CS features in these ML models leads to a significant enhancement in comparing the ASCVD prediction to utilizing CS features exclusively.

Cadaveric study of the ultrasound-guided erector spinae plane block over the transverse process of the twelfth thoracic vertebra in dogs: Transversal vs longitudinal approach

This study describes a transversal (TV) ultrasound-guided erector spinae plane (ESP) block technique over the transverse process of T12. And evaluates the distribution of the dye and affected nerves branches compared to a longitudinal (LNG) approach over the transverse process of T12 in canine cadavers. Secondly, it also compares de anatomy and dimensions of the transverse processes of T12 with T9 and T5. For this double-masked, cadaveric experimental study, 12 adult Beagle cadavers were injected with 0.6 mL/kg of dye/contrast. Spread was evaluated by computed tomography (CT) and dissection.Mean bodyweight was 9.76 (±0.59) kg. The TV and LNG approaches stained a median (range) of four (2–6) and three (1–6) medial branches of the dorsal rami of the spinal nerves, three (2–6) and three (2–5) lateral branches, and one (0−3) and one (0−4) ventral branches, respectively. Dye was detected in the epidural space in 55.6% and 66.7% of cases for the TV and LNG approaches, respectively (P=0.63). And in the ventral paravertebral compartment in 22.2% and lymphatics in 88.8% in both approaches. There were no statistical differences for the spread. The dorsolateral edge of the transverse process (TP) was not visible with CT at T12. The mean (±SD) length of the TP was significantly shorter at T12 [3.34 (±0.22)] mm, compared to T9 [6.08 (±0.47)] mm and T5 [5.93 (±0.62)] mm (P <0.001). This study showed similar distribution whether using a TV or LNG approach and differences in the anatomy and length of the T12 TP.

Fast multiple-trait genome-wide association analysis for correlated longitudinal measurements

Large-scale longitudinal biobank data can be leveraged to identify genetic variation contributing to human diseases progression and traits trajectories. While methods for genome-wide association studies (GWAS) of multiple correlated traits have been proposed, an efficient multiple-trait approach to model longitudinal phenotypes is not currently available. We developed GAMUT, a genome-wide association approach for multiple longitudinal traits. GAMUT employs a mixed-effects model to fit longitudinal outcomes where a fast algorithm for inversion by recursive partitioning of the random effects submatrix is introduced. To evaluate performance of the algorithms introduced and assess their statistical power and type I error, stochastic simulation was conducted. Consistent with our expectation, power was greater for cross-sectional (CS) than longitudinal (LT) effects, particularly with a diminishing LT/CS ratio. With a minimum minor allele count of 3 within genotype by time categories, observed type I error was roughly equal to theoretical genome-wide significance. Additionally, 28 blood-based biomarkers measured at 2 time points on participants of the UK Biobank were used to compare GAMUT against single-trait standard and longitudinal GWAS (including rate of change). Across all biomarkers, we observed 539 (CS) and 248 (LT) significant independent variants for the GAMUT method, and 513 (CS) and 30 (LT) for single-trait longitudinal GWAS, respectively. Only 37 variants were identified by modeling rates of change using standard GWAS.

The relationship of body mass index to setup errors, dosimetric parameters and incidence of radiation pneumonitis in non-small cell lung cancer patients undergoing intensity-modulated radiation therapy: a single-center observational study

Background The relationship among body mass index (BMI), setup error and radiation pneumonitis is not clearly illustrated. Objective The present study aimed to investigate the role of BMI in non-small cell lung cancer (NSCLC) patients’ radiation treatment, focusing on its relationship with setup error of patient positioning, the dosimetric parameters of intensity-modulated radiation therapy (IMRT) and the incidence of radiation pneumonitis. Methods This prospective observational study included 523 cases of NSCLC patients during 2020–2022. Patients were divided into different groups by different BMI. The setup error was obtained by cone beam CT (CBCT) at three positions, lateral (LAT), longitudinal (LNG) and vertical (VRT). IMRT dosimetric parameters of V 5, V 20, and mean dose were collected. Results Patients with BMI ≥28 kg/m2 showed significantly higher absolute values of LAT, LNG and VRT, higher V 5, V 20, mean dose, as well as higher total incidence of radiation pneumonitis and grade III radiation pneumonitis compared with patients with BMI <24 kg/m2 or 24–28 kg/m2. Spearman’s analysis demonstrated that the absolute values of LAT, LNG and VRT were positively correlated with BMI, and positive correlation existed among BMI, dosimetric parameters and setup errors. ROC curves showed that LAT in setup errors and V 5 in dosimetric parameters had the best diagnostic value for prediction of radiation pneumonitis. Only BMI, LAT, V 5 and V 20 were the independent risk factors for radiation pneumonitis. Conclusions Setup error caused by higher BMI might be associated with the dosimetric parameters, as well as the incidence of radiation pneumonitis in NSCLC patients.

Microstructure, Mechanical Properties, and Corrosion Behavior of Co‐Based Stellite 6 Multilayer Overlays Deposited on ASTM A36 Steel by Gas Metal Arc Welding Process

Hardfacing is an effective method for restoring the damaged part. Herein, cobalt‐based superalloy Stellite‐6 is deposited on A36 substrate using gas metal arc welding process. The mechanical properties, microstructure, and corrosion behavior of Stellite‐6 overlays on A36 substrate are examined. Defect‐free hard overlays are obtained, and a dilution ratio of 19.9% is achieved with weaving technique. X‐ray diffraction analysis reveals the presence of M7C3, M23C6, M6C, and martensite in the Stellite‐6 hard overlays. The microstructure of the deposit contains martensite, carbides, and interdendritic precipitates while the mean hardness is 471 HV0.5. Tensile testing with specimens extracted on the longitudinal (LD) and transverse (TD) orientation of the stellite‐6 deposit shows a strength above 950 MPa along with the brittle nature of fracture. Grain growth is epitaxial and shows dendritic morphologies. The higher fraction of high‐angle grain boundaries improves the tensile strength of the deposit and interface region. The localized corrosion behavior of stellite‐6 hard overlays is found to be excellent, and the corrosion analysis exhibits a corrosion rate of 0.10 mils per year (mpy). The outcomes of the study highlight the feasibility of Stellite‐6 hard overlays for extending the service life of A36 steel in chloride environments.

The spine and carina as a surrogate for target registration in cone-beam CT imaging verification in locally advanced lung cancer radiotherapy.

The aim of the study was to evaluate the accuracy of volumetric lung image guidance using the spine or carina as a surrogate to target for image registration, as the best approach is not established. Cone beam computed tomography images from the 1st, 10th, 15th, and 20th fraction in 40 lung cancer patients treated with radical radiotherapy were retrospectively registered to planning CT, using three approaches. The spine and carina alignment set-up deviations from a reference (tumour/lymph nodes) registration in the lateral (LAT), longitudinal (LONG) and vertical (VRT) directions were analysed and compared. Tumour location and nodal stage influence on registration accuracy were explored. The spine and carina mean set-up deviation from reference were largest in the LONG, with the best match in the VRT and LAT, respectively. Both strategies were more accurate in central tumours, with the carina being more precise in 50% LAT and 66% LONG mean deviations. For all measurements in all patients a carina vs. spine registration comparison showed improved carina accuracy in LAT and LONG. In comparative subgroup analysis the carina was superior compared to spine in LAT and LONG in centrally located tumours, N2 and N3. Both strategies were comparable for peripheral tumours and N0. Carina registration shows greater accuracy compared to spine in the LAT and LONG directions and is superior in central tumours, N2 and N3. The spine and carina surrogates are equally accurate for peripheral tumours and N0. We propose the carina as a surrogate to target for CBCT image registration in locally advanced lung cancer.

Synthesis of CdSe QDs decorated ZIF-8 composite for visible light assisted degradation of methylene blue

Metal organic frameworks have proven to be a crucial facet for the enhancement of environmental research because of their excellent properties, especially, extensive surface area. In the present study, we propose the synthesis route of CdSe quantum dots (CdSe QDs) and zinc imidazole framework-8 (ZIF-8) composite for the effective and potential methylene blue (MB) degradation via photocatalysis in visible range which is kinetically a pseudo first-order reaction. ZIF-8 itself is a photocatalyst but it has large band gap (4.8–5.1 eV) in ultraviolet region. The doping of CdSe QDs into the ZIF-8 matrix is done with the aim of deviating the photocatalytic activity to visible range by lowering of the band gap of ZIF-8 which was validated by UV–vis–DRS. XRD results indicated the decrease in the d-spacing, crystallite size and also provided the information about the positive microstrain for all the components. FTIR and Raman spectra confirmed the composite synthesis and the CdSe longitudinal (LO) and surface optical phonon modes (SO) along with the fundamental modes of ZIF-8, respectively. The elemental state of the constituent was established by XPS analysis. The adsorption isotherm data and the kinetic studies indicate that the CdSe-ZIF-8 composite has a great potential as a catalyst.

Sonographic Assessment of Uterine Biometry for the Diagnosis of Diffuse Adenomyosis in a Tertiary Outpatient Clinic.

Background: to compare several uterine biometric parameters at transvaginal ultrasound (TVUS) between adenomyosis and non-adenomyosis uteri and evaluate their role for the diagnosis of diffuse adenomyosis. Methods: prospective observational study conducted between the 1 February 2022 and the 30 April 2022. In this case, 56 patients with TVUS diagnosis of adenomyosis were included. A 1:1 ratio age and parity-matched group of non-adenomyosis patients was selected. We compared sonographic uterine biometric parameters (longitudinal (LD), anteroposterior (APD) and transverse (TD) diameters, volume, simple and complex diameter ratios) and investigated their diagnostic performance. Results: all sonographic parameters were significantly different between the study groups, except for TD/(LD+APD). Optimal cut-off values of APD and LD/APD showed the best sensitivity and specificity. APD diameter equal or superior to 39.5 mm (95% CI, 36.2–42.8) had sensitivity of 0.70 (95% CI, 0.57–0.80), specificity of 0.71 (95% CI, 0.59–0.82) and accuracy of 0.75 (95% CI, 0.66–0.84). LD/APD equal or inferior to 2.05 (95% CI, 1.96–2.13) showed sensitivity and specificity of 0.70 (95% CI, 0.57–0.80) each and accuracy of 0.72 (95% CI, 0.62–0.81). Conclusions: several biometric uterine parameters at TVUS in fertile-aged women were statistically different between adenomyosis and non-adenomyosis uteri, though their optimal cut-off values showed low accuracy in diagnosing adenomyosis.

Influence of sex, cigarette smoking and airway inflammation on treatable traits in CBIOPRED severe asthma.

Influence of sex, cigarette smoking and airway inflammation on treatable traits in CBIOPRED severe asthma.

Mathematical Modeling to Guide Experimental Design: T Cell Clustering as a Case Study.

Mathematical modeling provides a rigorous way to quantify immunological processes and discriminate between alternative mechanisms driving specific biological phenomena. It is typical that mathematical models of immunological phenomena are developed by modelers to explain specific sets of experimental data after the data have been collected by experimental collaborators. Whether the available data are sufficient to accurately estimate model parameters or to discriminate between alternative models is not typically investigated. While previously collected data may be sufficient to guide development of alternative models and help estimating model parameters, such data often do not allow to discriminate between alternative models. As a case study, we develop a series of power analyses to determine optimal sample sizes that allow for accurate estimation of model parameters and for discrimination between alternative models describing clustering of CD8 T cells around Plasmodium liver stages. In our typical experiments, mice are infected intravenously with Plasmodium sporozoites that invade hepatocytes (liver cells), and then activated CD8 T cells are transferred into the infected mice. The number of T cells found in the vicinity of individual infected hepatocytes at different times after T cell transfer is counted using intravital microscopy. We previously developed a series of mathematical models aimed to explain highly variable number of T cells per parasite; one of such models, the density-dependent recruitment (DDR) model, fitted the data from preliminary experiments better than the alternative models, such as the density-independent exit (DIE) model. Here, we show that the ability to discriminate between these alternative models depends on the number of parasites imaged in the analysis; analysis of about [Formula: see text] parasites at 2, 4, and 8h after T cell transfer will allow for over 95% probability to select the correct model. The type of data collected also has an impact; following T cell clustering around individual parasites over time (called as longitudinal (LT) data) allows for a more precise and less biased estimates of the parameters of the DDR model than that generated from a more traditional way of imaging individual parasites in different liver areas/mice (cross-sectional (CS) data). However, LT imaging comes at a cost of a need to keep the mice alive under the microscope for hours which may be ethically unacceptable. We finally show that the number of time points at which the measurements are taken also impacts the precision of estimation of DDR model parameters; in particular, measuring T cell clustering at one time point does not allow accurately estimating all parameters of the DDR model. Using our case study, we propose a general framework on how mathematical modeling can be used to guide experimental designs and power analyses of complex biological processes.

Phonon-drag thermopower and thermoelectric performance of MoS2 monolayer in quantizing magnetic field

We present a theory of phonon-drag thermopower, , in MoS2 monolayer at a low-temperature regime in the presence of a quantizing magnetic field B. Our calculations for consider the electron–acoustic phonon interaction via deformation potential (DP) and piezoelectric (PE) couplings for longitudinal (LA) and transverse (TA) phonon modes. The unscreened TA-DP is found to dominate over other mechanisms. The is found to oscillate with the magnetic field where the lifting effect of the valley and spin degeneracies in MoS2 monolayer has been clearly observed. An enhanced with a peak value of mV K−1 at about T = 10 K is predicted, which is closer to the zero field experimental observation. In the Bloch–Grüneisen regime the temperature dependence of gives the power-law , where δ e varies marginally around 3 and 5 for unscreened and screened couplings, respectively. In addition, is smaller for larger electron density n e . The power factor PF is found to increase with temperature T, decrease with n e , and oscillate with B. The prediction of an increase of thermal conductivity with temperature and the magnetic field is responsible for the limit of the figure of merit (ZT). At a particular magnetic field and temperature, ZT can be maximized by optimizing electron density. By fixing cm−2, the highest ZT is found to be 0.57 at T = 5.8 K and B = 12.1 T. Our findings are compared with those in graphene and MoS2 for the zero-magnetic field.

Automating and improving cardiovascular disease prediction using Machine learning and EMR data features from a regional healthcare system

BackgroundThe ACC/AHA Pooled Cohort Equations (PCE) Risk Calculator is widely used in the US for primary prevention of atherosclerotic cardiovascular disease (ASCVD), but may under- or over-estimate risk in some populations. We therefore designed an automated, population-specific ASCVD risk calculator using machine-learning (ML) methods and electronic medical record (EMR) data, and compared its predictive power with that of the PCE calculator. Methods and FindingsWe collected data from 101,110 unique EMRs of living patients from January 1, 2009 to April 30, 2020. ML techniques were applied to patient datasets that included either only cross-sectional (CS) features, or CS combined with longitudinal (LT) features derived from vital statistics and laboratory values. We compared the utility of the models using a proposed new cost measure (Screened Cases Percentage @ Sensitivity level).All ML models tested achieved better predictive power than the PCE risk calculator. The random forest ML technique (RF) applied on the combination of CS and LT features (RF-LTC) produced the best area under curve (AUC) score of 0.902 (95% confidence interval (CI), 0.895–0.910). To detect 90% of all positive ASCVD cases, the best ML model required screening only 43% of patients, while the PCE risk calculator required screening 69% of patients. ConclusionsPrediction models built using ML techniques improved ASCVD prediction and reduced the number of screenings required to predict ASCVD when compared with the PCE calculator, alone. Combining LT and CS features in the ML models significantly improved ASCVD prediction compared with using CS features, alone.

Nanotube heat conductors under tensile strain: Reducing the three-phonon scattering strength of acoustic phonons

Acoustic phonons play a special role in lattice heat transport, and confining these low-energy modes in low-dimensional materials may enable nontrivial transport phenomena. By applying lowest-order anharmonic perturbation theory to an atomistic model of a carbon nanotube, we investigate numerically and analytically the spectrum of three-phonon scattering channels in which at least one phonon is of low energy. Our calculations show that acoustic longitudinal (LA), flexural (FA), and twisting (TW) modes in nanotubes exhibit a distinct dissipative behavior in the long-wavelength limit, $|k|\ensuremath{\rightarrow}0$, which manifests itself in scattering rates that scale as ${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{LA}}\ensuremath{\sim}{|k|}^{\ensuremath{-}1/2}, {\mathrm{\ensuremath{\Gamma}}}_{\mathrm{FA}}\ensuremath{\sim}{k}^{0}$, and ${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{TW}}\ensuremath{\sim}{|k|}^{1/2}$. These scaling relations are a consequence of the harmonic lattice approximation and critically depend on the condition that tubes are free of mechanical strain. In this regard, we show that small amounts of tensile lattice strain $\ensuremath{\epsilon}$ reduce the strength of anharmonic scattering, resulting in strain-modulated rates that, in the long-wavelength limit, obey $\mathrm{\ensuremath{\Gamma}}\ensuremath{\sim}{\ensuremath{\epsilon}}^{r}{|k|}^{s}$ with $r\ensuremath{\le}0$ and $s\ensuremath{\ge}1$, irrespectively of acoustic mode polarization. Under the single-mode relaxation time approximation of the linearized Peierls-Boltzmann equation (PBE), the long-tube limit of lattice thermal conductivity in stress-free and stretched tube configurations can be unambiguously characterized. Going beyond relaxation time approximations, analytical results obtained in the present study may help to benchmark numerical routines which aim at deriving the thermal conductivity of nanotubes from an exact solution of the PBE.

Temperature dependence of the optical phonon reflection band in GaP

We explore the effect of temperatures between 80 and 720 K on the energy and linewidth of zone-center transverse (TO) and longitudinal (LO) optical phonons in bulk gallium phosphide (GaP) using Fourier transform infrared ellipsometry from 0.03 to 0.60 eV. We extract the optical phonon parameters of GaP by fitting the ellipsometric angles with the Lowndes–Gervais model, which applies two different broadening parameters to the TO and LO phonons. In GaP, the two-phonon density of states is larger for the decay of TO phonons than for LO phonons. Therefore, we observed a larger TO phonon broadening (compared to the LO phonon) and an asymmetric reststrahlen line shape. This would lead to a negative imaginary part of the dielectric function just above the LO phonon energy but the addition of two-phonon absorption avoids this. We find a temperature-dependent redshift and broadening of TO and LO phonons with increasing temperature due to thermal expansion and anharmonic phonon-phonon scattering, involving three and four phonon decay processes. We also investigate the temperature dependence of the high-frequency dielectric constant. Its variation is explained by thermal expansion and the temperature dependence of the Penn gap.

Effects of SiC orientations and particle sizes on the low cycle fatigue properties of SiCp/A356 composite

Herein, effects of SiC orientations and sizes on fatigue behaviors of SiCp/A356 composites are investigated. Results reveal longitudinal (LT) samples possess superior fatigue properties compared to transverse (TR) samples. Adding 4.5 μm SiC, deformation mechanisms transfer from dislocation pile-ups along Si to along both SiC and Si, contributing to SiC decohesion and degradation of fatigue resistances. Adding 20 μm SiC, SiC decohesion prevails at TR sample since angle θ between SiC orientation and loading direction locates 45°-135°, while broken SiC particles are predominant at LT sample as θ < 45° or θ > 135°. These further decline their fatigue life.

Strain tuned thermal conductivity reduction in Indium Arsenide (InAs) – A first-principles study

Indium based semiconductors are promising materials for thermoelectric devices. Efficiency of a thermoelectric material can be improved by minimizing the lattice thermal conductivity (k). Using first-principles calculations, we report ~20% reduction in in-plane thermal conductivity of Indium arsenide (InAs) with 3% biaxial compressive strain. At 300 K, the bulk thermal conductivity of 33.85 Wm−1K−1 computed for unstrained indium arsenide (InAs) is reduced to 27 Wm−1K−1 for the 3% biaxially strained InAs. Systematic analysis of the effect of applied biaxial strain on phonon group velocities and phonon scattering rates of longitudinal (LA) and transverse (TA) acoustic phonon modes is carried out. Our results shed a light on modulating thermal conductivity of materials through biaxial strain.

Thermally Activated Optical Absorption into Polaronic States in Hematite.

Polaron formation, whereby an electron or hole strongly couples to a lattice distortion, inhibits the carrier mobility of many first-row transition metal oxide semiconductors. Recently reported XUV transient absorption measurements of hematite (α-Fe2O3) demonstrate formation of electron small polarons upon photoexcitation into an undistorted charge-transfer state followed by subpicosecond lattice reorganization. Here, we show that polaronic states of hematite can be accessed directly via optical transitions from the ground state in a thermally activated lattice. Thermal difference spectra collected from 30 to 573 K combined with Stokes resonance Raman spectra indicate strong coupling between optical transitions near the band-edge (2.1-2.3 eV) and zone-center a1g and longitudinal (LO) optical phonons. Density functional theory calculations of the electronic and vibrational structures of pristine and polaron-distorted hematite lattices confirm that the geometric distortion corresponding to electron small polaron formation lies along the 28-meV a1g and 81-meV LO phonon coordinates and reproduce the features observed in the experimental thermal difference and resonance Raman spectra.

Seismic performance evaluation of a steel tubular bridge pier in a five-span continuous girder bridge system

The seismic performance of a steel tubular bridge pier in a five-span continuous girder bridge system was evaluated through dynamic non-linear time-history analysis under strong ground motions. The seismic performance of the hollow steel tubular (HST) and partially concrete-filled steel tubular (PCFST) bridge piers was assessed with different eccentricities of superstructure. Considering the variation of ground classification under rare earthquakes, six seismic waves were input. The analytical results indicate that the eccentricity of superstructure has little effect on the maximum displacement response of the HST bridge piers and the PCFST bridge piers under ground motion excitations in the longitudinal (LG) direction; however, under the ground motion excitations in the transverse (TR) direction, the maximum displacement response of the bridge piers increases when the eccentricity (e/H) increases from 0 to 0.2, which implies that eccentricity affects the seismic response of the two types of piers. Both in the LG direction and TR direction, the HST piers have reached their yield strengths; stress concentration and local buckling were observed around the plastic hinge zone and the load bearing capacity decreases. Although the PCFST piers entered the elasto-plastic range, the expansion of local buckling deformation of the steel tubular column has been restrained by the concrete in-fill. According to the simulated results, the PCFST pier exhibits high ductility and bearing capacity, which can improve the seismic performance of the bridge system.

The Correlation between Structural and Optical Properties of Zinc Hydroxide Nanoparticle in Supports Photocatalytic Performance

- Green synthesized Zn(OH)2 mediated by Coleus blumei Benth leaf for pH: 4, 7, 10 and for calcination temperature: 400 °C, 450 °C, 500 °C, 550 °C, and 600 °C have been characterized by using Fourier transform infra-red (FTIR), ultraviolet–visible (Uv–Vis), and X-ray diffraction (XRD). The bonding formation present Zn– O –H, H– O –H, O –H, and Zn–O indicated Zn(OH)2 nanocrystal successfully synthesized. The optical, dielectric properties, and energy loss function were quantitatively determined from the FTIR spectra by using Kramers-Kronig (KK) dispersion relation. The distance between longitudinal (LO) and transverse (TO) optical phonon vibration mode Δ (LO-TO) and the bandgap increases with increasing the calcination temperature for all pH due to the amount of covalent bond is increase. The best calcination temperature is 600 °C and pH 7 indicated by the rate of the degradation performance is faster than the other temperature and pH. In this study shows FTIR spectra effective ways for determining the optical and dielectric properties, optical phonon vibration mode, and energy loss function of Zn(OH)2 material. • The Zn-O-H, H-O-H, O-H, and Zn-O bonding indicated formed of Zn(OH) 2 nanocrystal. • The n and k , ε 1 and ε 2 (ω), Im ( - 1 / ε 1 ( ω ) ) determined from FTIR spectra by applying K-K relation. • Distance optical phonon vibration (D(LO-TO)) is increases with increasing the calcination temperature for all pH. • The band gap increase with increasing the calcination temperature. • The best calcination temperature for photocatalyst is 600 o C.