Predicting the strength of seashell concrete using Adaptive Neuro-Fuzzy Inference System: An experimental study

La concha marina es una capa exterior dura y protectora creada por un animal que vive en el mar. A menudo se encuentran conchas marinas vacías y lavadas por las olas sobre las playas. Este producto marino puede ser utilizado como reemplazo parcial del agregado grueso en el concreto o del cemento en el concreto. Este artículo describe el uso de polvo de conchas marinas y agregados en el concreto para reemplazar el cemento y los agregados gruesos. El efecto de los residuos de conchas marinas en el concreto fue estudiado en términos de su resistencia a la compresión, resistencia a la tracción y resistencia a la flexión después de 28. 56 y 90 días de curado. El reemplazo de cemento por polvo de conchas marinas fue de 10%, 20% y 30% y el reemplazo de agregado grueso por agregado de concha marina fue 5%, 10% y 15%. Las propiedades del concreto de concha marina fueron comparadas con una muestra de mezcla control de grado M25 de concreto. También se ha intentado predecir la resistencia del concreto de concha marina utilizando un Sistema de Inferencia Adaptativo Neuro-Fuzzy (ANFIS). La predicción de la fuerza con este sistema estuvo de acuerdo con la fuerza experimental con un error mínimo de menos del 5%. Este estudio concluye que el reemplazo parcial de cemento y de agregado grueso por residuos de concha marina aumenta significativamente las propiedades mecánicas del concreto y permite la utilización adecuada de estos desechos de conchas marinas como material sostenible para el concreto.Seashell is a hard, protective outer layer created by an animal that lives in the sea. Empty seashells are often found washed up on beaches by beachcombers. This marine by-product can be used to partial replacement of coarse aggregate or cement in concrete. This paper describes the use of seashell powder and aggregate in the concrete for the replacement of cement and coarse aggregate. The effect of seashell waste in the concrete was studied in terms of its compressive strength, tensile strength and flexural strength after 28, 56 and 90 days of curing. The replacement of cement by seashell powder were 10%, 20% and 30% and replacement of coarse aggregate by seashell aggregate are 5%, 10% and 15%. The properties of seashell concrete were compared with control mix specimen of M25 grade of concrete. Also, it has been tried to predict the strength of the seashell concrete utilizing adaptive neuro-fuzzy inference system (ANFIS). The prediction of strength with the tool was agreeable with the experimental strength with the minimal error of less than 5%. This study concludes, that partial replacement of cement and coarse aggregate by seashell waste enhances the mechanical properties of the concrete significantly and enable proper utilization of these seashell waste as sustainable material for the concrete

Flexural Behaviour of a Cold-Formed Steel-Concrete Composite Beam with Channel Type Shear Connector – An Experimental and Analytical Study

Steel-concrete composite structures are widely used in the current construction of bridges and multi-storey buildings. The effect of shear connectors in a cold-formed steel-composite beam was studied under flexure. The number of channel connectors in the specimen was varied and the same was compared with a specimen without shear connectors. The performance and failure of cold-formed steel-composite beams were then studied. The presence of shear connectors in the tension zone prevents the formation of cracks which are the major cause of failure in a beam subjected to bending. The load-carrying capacity is greater in a composite beam and an increase in the number of channel connectors from one to five increases the load-carrying capacity by 60 % as compared to a specimen without a connector. A composite beam with five connectors is more ductile, with a ductility factor of 14. The Composite beams were also analysed using the finite element software ANSYS and were found to have good agreement with the experimental results

Analytical study on the behaviour of composite space truss structures with openings in a concrete slab

A space truss structural system is a three-dimensional arrangement of linear elements in a pyramid pattern forming a Double Layer Grid (DLG) system. Space trusses are an elegant and economical means of covering larger areas such as roof systems, in a wide variety of applications such as a stadium, aircraft-hanger, assembly hall, etc. The major problem encountered in using the space truss as a roofing system is the sudden failure of the whole structure due to critical buckling of the top chord member. Earlier research has shown that the optimal solution to overcome such a failure is by providing a small thickness of concrete slab over the space truss, so that the space truss with concrete slab (Composite Space Truss) will act as a floor system for the multi-storey building. For better ventilation and lighting in the building, the need for openings in the composite space truss is unavoidable; however, providing an opening in the concrete slab will reduce the load carrying capacity of the structure. The analysis of a composite space truss of size 30m x 30m with all possible locations of openings for four different support conditions was carried out using ANSYS in order to study the load - deflection behaviour. Further, the ductility factor and energy absorption capacity of the composite space truss with different locations of slab openings were compared

Flexural Behaviour of a Cold-Formed Steel-Concrete Composite Beam with Channel Type Shear Connector – An Experimental and Analytical Study

Steel-concrete composite structures are widely used in the current construction of bridges and multi-storey buildings. The effect of shear connectors in a cold-formed steel-composite beam was studied under flexure. The number of channel connectors in the specimen was varied and the same was compared with a specimen without shear connectors. The performance and failure of cold-formed steel-composite beams were then studied. The presence of shear connectors in the tension zone prevents the formation of cracks which are the major cause of failure in a beam subjected to bending. The load-carrying capacity is greater in a composite beam and an increase in the number of channel connectors from one to five increases the load-carrying capacity by 60 % as compared to a specimen without a connector. A composite beam with five connectors is more ductile, with a ductility factor of 14. The Composite beams were also analysed using the finite element software ANSYS and were found to have good agreement with the experimental results

Comparison of Air Pollutants and Air Quality Index using Spatio-Temporal Variation in Chennai City, Tamil Nadu

In recent years, air pollution in Chennai city in India causes some health effects. This study examines the spatial-temporal characteristics of ambient air quality in five stations Adyar, Anna Nagar, Kilpauk, Nungambakkam and Thiyagaraya Nagar from 2017 to 2022. The surface level aerosol pollutants like particulate matters (PM2.5 & PM10) and gaseous pollutants Sulfur dioxide (SO2) & Nitrogen dioxide (NO2) were obtained from Tamilnadu Pollution Control Board (TPCB) for five years which includes pre-COVID, during and Post- COVID - period. The results showed that fine particulate matter (PM2.5) and coarse particulate matter (PM10), decreased by 19.49% and 31.91% respectively and gaseous pollutant SO2 and NO2 slightly increased by 7.84% and 1.2 % respectively during 2021 as compared with 2017.The particulate matter (PM2.5 & PM10) level exceeded the National Ambient Air Quality Standards (NAAQS) as well as the WHO recommended Air Quality Guidelines during 2017-2019(Pre-COVID) and low during 2020-2021(During COVID and Post-COVID). The average Air Quality Index (AQI), calculated from the date decreased from 120(2018-2019) to 93(2020-2021) in Chennai city. The AQI and PM2.5/PM10 showed the highest pollution level in winter and lower in summer. PM10 was the primary pollutant, followed by NO2, PM2.5 & SO2 with spatial and temporal variations. The proportion of pollutants PM2.5 and PM10 decreased but increased for SO2 and NO2. This study offers useful data and resources for further research on Chennai's air quality

Bimetallic Au–Ag/CeO₂ Catalysts for Preferential Oxidation of CO in Hydrogen-Rich Stream: Effect of Calcination Temperature

Au–Ag/CeO₂ catalysts with various Au/Ag atomic ratios were prepared by deposition–precipitation method. These catalysts were tested for preferential oxidation of carbon monoxide (PROX). These catalysts have been characterized by XRD, TEM, TPR, and XPS techniques to gain the structural information on the supported metal catalysts. Fine gold nanoparticles around 2–4 nm were formed and dispersed well on the support. Au–Ag/CeO₂ with Au/Ag atomic ratio of 5:5 showed higher catalytic activity than monometallic and other bimetallic Au–Ag/CeO₂ catalysts with Au/Ag ratios of 9:1 and 7:3. The CO selectivity increased with increasing silver amount. In Au–Ag/CeO₂ catalysts, the higher calcination temperature resulted in gold sintering, which resulted in lower activity. Characterization by XPS and TPR revealed that the presence of different gold and silver species plays an important role in the activity of the catalyst. The formation of bimetallic alloy in Au–Ag/CeO₂ catalyst with Au/Ag ratio of 5:5 which showed a lower reduction temperature, is the reason for its excellent performance toward PROX reaction. The bimetallic catalyst also exhibited higher stability than the monometallic catalysts. The electronic structures of both gold and silver can be crucial to CO bonding. CO adsorbs strongly on Au. Ag⁺ was the active species for CO oxidation. The presence of both Au⁰ and Ag⁺ synergistically facilitate CO oxidation by the reaction between CO and O₂ to form CO₂. The formation of the bimetallic nanoalloy enhanced the CO oxidation

Flexural Strength of Steel-Concrete Composite Beams Under Two-Point Loading

This study investigates the flexural strength of simply-supported steel–concrete composite beams under two-point loading. A total of four specimens were tested to failure for varying parameters including type of connectors (stud and channel) and number of connectors (two and four). ANSYS software was used to establish the finite element models that can simulate the flexural behaviour of the composite beam. The test results show that a beam with channel connectors performs better than a beam with stud connectors. The composite beam with two connectors between the beam and slab causes additional deflection due to slippage in the connectors, when compared to the beam with four connectors. The results from the analytical model are in good agreement with the experimental results

Flexural Strength of Steel-Concrete Composite Beams Under Two-Point Loading

This study investigates the flexural strength of simply-supported steel–concrete composite beams under two-point loading. A total of four specimens were tested to failure for varying parameters including type of connectors (stud and channel) and number of connectors (two and four). ANSYS software was used to establish the finite element models that can simulate the flexural behaviour of the composite beam. The test results show that a beam with channel connectors performs better than a beam with stud connectors. The composite beam with two connectors between the beam and slab causes additional deflection due to slippage in the connectors, when compared to the beam with four connectors. The results from the analytical model are in good agreement with the experimental results

Fluoranthene-based derivatives for multimodal anti-counterfeiting and detection of nitroaromatics

In this study, we developed two novel sky blue fluorescent fluorophores comprising ethyl alcohol (FOH) and ethanethiol (FSH) units appended to fluoranthene at the periphery. Single Crystal X-Ray Diffraction (SC-XRD) studies reveal that the molecular flexibility of alkyl chains leads to distinct diagonal (FOH) and ladder (FSH) shaped supramolecular arrangements in the crystal lattices. Detailed photophysical and DFT studies showed that FOH and FSH demonstrate high sensitivity and selectivity towards the detection of trinitrophenol (TNP). FSH exhibits high quenching efficiency (similar to 84%), a rate constant of KSV = 1.1 x 104 M-1 with a limit of detection of similar to 97 ppm in THF, and similar to 76 ppm in river water. Mechanistic investigation through NMR and SC-XRD of the FSH adduct with 1,3-dinitrobenzene (DNB) reveal strong pi-pi interactions (3.518 angstrom). Furthermore, photoinduced electron transfer occurs from the fluorophores to the nitro analytes and leads to strong intermolecular interactions using the static quenching mechanism. Both fluorophores were employed in advanced surveillance to identify finger marks on a wide range of substrates (glass, cellophane tape, aluminium foil and floor tiles) with different resolutions to provide an unadorned and lucrative method for viewing the latent fingerprints (LFPs) with exceptionally consistent evidence of up to level 3 and without the requirement for post-treatments, leading to promising applications for onsite forensic analysis. Furthermore, FOH and FSH were evaluated in 72 hpf zebrafish larvae/embryos to demonstrate the non-toxicological behaviour and fluorescence imaging/tracking. Two novel fluoranthene ensembles with ethyl alcohol (FOH) and ethanethiol (FSH) functionality with distinct diagonal and ladder arrangements in the crystal lattices were developed for Latent Fingerprints (LFPs) towards analysis of explosives.Web of Science4236270625