This paper presents a numerical method for estimating the curvature, deflection and moment capacity of hybrid FRP/steel reinforced concrete beams. A sectional analysis is first carried out to predict ...the moment–curvature relationship from which beam deflection and moment capacity are then calculated. Based on the amount of FRP bars, different failure modes were identified, namely tensile rupture of FRP bars and concrete crushing before or after yielding of steel reinforcement. Comparisons between theoretical and experimental results of tests conducted elsewhere show that the proposed numerical technique can accurately predict moment capacity, curvature and deflection of hybrid FRP/steel reinforced concrete beams. The numerical results also indicated that beam ductility and stiffness are improved when steel reinforcement is added to FRP reinforced concrete beams.
The bond strength between fibre-reinforced polymer (FRP) rebars and concrete is one of the most significant aspects of composite behaviour for rebars and concrete. In this study, a database of 408 ...beam type specimens consisting of beam end specimens, beam anchorage specimens and splice beam specimens was compiled from the current literature and used to develop a simple prediction using the artificial neural network (ANN). The data used for modelling were organised in a format of eight input parameters that include FRP type, cover bar surface, confinement, bar diameter (
), concrete compressive strength
, minimum cover-to-bar-diameter ratio (
), bar-development-length-to-bar-diameter ratio (
), and the ratio of the area of transverse reinforcement to the product of transverse reinforcement spacing, the number of developed bars and bar diameters (
/snd
). Additionally, a simple prediction formula by regression analysis was developed. The root mean square error and
values of the testing data were found in order to compare the results of both ANN and the proposed model with existing regulations. The new ANN model predicts the bond strength of FRP bars in reinforced concrete with 0.8989
, thus yielding better results when compared with existing regulations.
A numerical method for estimating the curvature, deflection and moment capacity of reinforced concrete beams strengthened with prestressed near-surface-mounted (NSM) FRP bars/strips is presented. A ...sectional analysis is carried out to predict the moment–curvature relationship from which beam deflections and moment capacity are then calculated. Based on the amount of FRP bars, different failure modes were identified, namely tensile rupture of prestressed FRP bars and concrete crushing before or after yielding of steel reinforcement. Comparisons between experimental results available in the literature and predicted curvature, moment capacity and deflection of reinforced concrete beams with prestressed NSM FRP reinforcements show good agreement. A parametric study concluded that higher prestressing levels improved the cracking and yielding loads, but decreased the beam ductility compared with beams strengthened with nonprestressed NSM FRP bars/strips.
Large amount of waste tires are generated progressively every year. Therefore, many researches have been conducted on using recycled tire products in several civil engineering products. This paper is ...focusing on feasibility of using recycled steel fibers from waste tires as reinforcement in functionally graded self-compacting concrete (SCC). Firstly, fresh and hardened properties of the normal and steel fiber reinforced concretes were investigated. After obtaining the mechanical properties of steel fiber reinforced SCC, 16 multi-layered beams were tested under 4 point bending test by considering various fiber fractions and layer thickness. Additionally, SEM images were used to maintain the failure mechanisms between steel fibers and concrete matrix.
Abstract
We use the energy-balance code magphys to determine stellar and dust masses, and dust corrected star formation rates for over 200 000 GAMA galaxies, 170 000 G10-COSMOS galaxies, and 200 000 ...3D-HST galaxies. Our values agree well with previously reported measurements and constitute a representative and homogeneous data set spanning a broad range in stellar-mass (108–1012 M⊙), dust-mass (106–109 M⊙), and star formation rates (0.01–100 M⊙yr−1), and over a broad redshift range (0.0 < z < 5.0). We combine these data to measure the cosmic star formation history (CSFH), the stellar-mass density (SMD), and the dust-mass density (DMD) over a 12 Gyr timeline. The data mostly agree with previous estimates, where they exist, and provide a quasi-homogeneous data set using consistent mass and star formation estimators with consistent underlying assumptions over the full time range. As a consequence our formal errors are significantly reduced when compared to the historic literature. Integrating our CSFH we precisely reproduce the SMD
with an interstellar medium replenishment factor of 0.50 ± 0.07, consistent with our choice of Chabrier initial mass function plus some modest amount of stripped stellar mass. Exploring the cosmic dust density evolution, we find a gradual increase in dust density with lookback time. We build a simple phenomenological model from the CSFH to account for the dust-mass evolution, and infer two key conclusions: (1) For every unit of stellar mass which is formed 0.0065–0.004 units of dust mass is also formed. (2) Over the history of the Universe approximately 90–95 per cent of all dust formed has been destroyed and/or ejected.
An investigation was conducted to analyse the impact of vacuum impregnation (VI) on aroma profile of intermediate-moisture apricots. cv. Hacihaliloğlu and cv. Kabaaşı apricots were immersed in a ...variety of solutions, including citric acid and sucrose, as well as plant extracts like rosehip, roselle, and rhubarb. According to the results, solid loss and water gain were observed in all infused samples by VI, while osmotic dehydration occurred in the apricots after immersing in sucrose solution. After all process, a total of 71 volatile compounds were detected in the Hacihaliloglu variety and 66 in the Kabaasi variety. These components are aldehydes, ketones, esters, furan compounds, alcohols, terpenes, isoprenoids, and acids, collected in eight groups. Vacuum impregnation had positive effects on terpenes in both cultivars.
► A CANN model was developed for non-circular FRP confined RC columns. ► The results of sixty-one column tests are taken into account during testing and training phases of CANN modeling. ► 99.52% ...accuracy rate was obtained. ► The proposed CANN model is successful for both FRP confined and unconfined columns.
This study presents the application of combined artificial neural networks (CANNs) for the flexural capacity estimation of quadrilateral fiber-reinforced polymer (FRP) confined reinforced concrete (RC) columns. A database on quadrilateral FRP confined RC columns subjected to axial load and moment was obtained from experimental studies in the literature; CANN models were built, trained and tested. Then the flexural capacities of quadrilateral FRP confined RC columns were determined using the developed CANN model. Single and combined ANN was used for the first time in the literature for the estimation of flexural capacities of non-circular fiber-reinforced polymer (FRP) confined reinforced concrete (RC) columns. The accuracies of the proposed ANN and CANN models were more satisfactory as compared to the existing conventional approaches in the literature. Moreover, the proposed CANN models’ results had lower prediction error than those of the single ANN model.
We present single-Sérsic two-dimensional (2D) model fits to 167 600 galaxies modelled independently in the ugrizYJHK bandpasses using reprocessed Sloan Digital Sky Survey Data Release Seven (SDSS ...DR7) and UKIRT Infrared Deep Sky Survey Large Area Survey imaging data available from the Galaxy And Mass Assembly (GAMA) data base. In order to facilitate this study we developed Structural Investigation of Galaxies via Model Analysis (sigma), an r wrapper around several contemporary astronomy software packages including source extractor, psf extractor and galfit 3. sigma produces realistic 2D model fits to galaxies, employing automatic adaptive background subtraction and empirical point spread function measurements on the fly for each galaxy in GAMA. Using these results, we define a common coverage area across the three GAMA regions containing 138 269 galaxies. We provide Sérsic magnitudes truncated at 10r
e which show good agreement with SDSS Petrosian and GAMA photometry for low Sérsic index systems (n < 4), and much improved photometry for high Sérsic index systems (n > 4), recovering as much as Δm= 0.5 mag in the r band. We employ a K-band Sérsic index/u−r colour relation to delineate the massive (n > ∼2) early-type galaxies (ETGs) from the late-type galaxies (LTGs). The mean Sérsic index of these ETGs shows a smooth variation with wavelength, increasing by 30 per cent from g through K. LTGs exhibit a more extreme change in Sérsic index, increasing by 52 per cent across the same range. In addition, ETGs and LTGs exhibit a 38 and 25 per cent decrease, respectively, in half-light radius from g through K. These trends are shown to arise due to the effects of dust attenuation and stellar population/metallicity gradients within galaxy populations.
It has been proposed that salicylic acid (SA) acts as an endogenous signal molecule responsible for inducing abiotic stress tolerance in plants. The effect of varying salicylic acid (SA) supply (0, ...0.1, 0.5 and 1.0
mM) on growth, mineral uptake, membrane permeability, lipid peroxidation, H
2O
2 concentration, UV-absorbing substances, chlorophyll and carotenoid concentrations of NaCl (40
mM) stressed maize (
Zea mays L.) was investigated. Exogenously applied SA increased plant growth significantly both in saline and non-saline conditions. As a consequence of salinity stress, lipid peroxidation, measured in terms of malondialdehyde (MDA) content and membrane permeability was decreased by SA. UV-absorbing substances (UVAS) and H
2O
2 concentration were increased by increasing levels of SA. SA also strongly inhibited Na
+ and Cl
− accumulation, but stimulated N, Mg, Fe, Mn and Cu concentrations of salt stressed maize plants. These results suggest that SA could be used as a potential growth regulator to improve plant salinity stress resistance.
Abstract This paper investigates the properties of self-compacting concrete with waste steel bead wires obtained as a result of the separation of waste tires. Waste steel bead wires were added to ...concrete between 1% and 5% by weight with an increment of 1%. In total, 54 cubes, 6 cylinders and 6 beams were cast, cured and tested in according to various standards to obtain the compressive, splitting tensile and flexural strengths, respectively. In addition, 6 cubes were left in salty water solution with a salt concentration of 4% for 120 days and tested in compression. A scanning electron microscopy (SEM) was also conducted on samples after failure. Test results showed that short time corrosion of steel fibers does not affect the mechanical properties. Also, the increase in the ratio of steel fiber was found to contribute positively to the mechanical properties of concrete up to 4%, beyond which, mechanical properties were reduced. Finally, in the samples subjected to bending tests, it has been found that a 6-fold increase in bending strength compared to the reference (non-fiber) sample was achieved in case of steel fiber ratio of 4% and 5%.
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