•Clay bricks were reinforced with natural and synthetic fibers.•Physical properties of fiber reinforced bricks were investigated.•Relationship among bulk density, water absorption and porosity were ...established.•Relationship was also established between water absorption and thermal conductivity.•Thermal conductivity was also verified analytically by finite element analysis.
Buildings consume more than 30% of primary energy in order to maintain their indoor temperature which varied due to heating and cooling losses. This energy consumption has been increased dramatically through the last decade due to population explosion, more time is spent indoors along with climate changes. Energy efficient building materials are the ultimate requirement and several insulating materials have been developed to minimize the carbon foot prints. Current research work deals with the conversion of conventional terra cotta brick to porous low thermal conductive brick using various organic fibers. Bamboo, jute, coir, sisal and polyester fibers are used in this research work while all having low embodied energy. Water absorption index of fibers and brick, bulk density and porosity of all types of bricks were measured and relationships with water absorption were also established. Reduction in thermal conductivity was observed, using steady state conduction apparatus: upto 18% reduction in thermal conductivity. Reduction in bulk density, thermal conductivity, and increase in water absorption were all attributed to porosity created by burning of fibers. Thermal conductivity was also estimated analytically by using finite element simulation using ANSYS platform, heat flow and temperature at both ends were selected parameters for input, whereas heat flux and temperature gradient were output. The maximum difference between experimental and analytical thermal conductivity was varied up to 7.8%, which verify its applicability.
Abstract
The researchers are continuously working on nanomaterials and exploring many multidisciplinary applications in thermal engineering, biomedical and industrial systems. In current problem, the ...analytical simulations for performed for thermos-migration flow of nanofluid subject to the thermal radiation and porous media. The moving wedge endorsed the flow pattern. The heat source effects are also utilized to improves the heat transfer rate. The applications of thermophoresis phenomenon are addressed. The formulated set of expressions are analytically treated with implementation of variational iteration method (VIM). The simulations are verified by making the comparison the numerical date with existing literature. The VIM analytical can effectively tackle the nonlinear coupled flow system effectively. The physical impact for flow regime due to different parameters is highlighted. Moreover, the numerical outcomes are listed for Nusselt number.
In this study, selenium nanoparticles (SeNPs) and cerium oxide nanoparticles (CeONPs) were synthesized by using the extract of
leaves, and
rhizomes, respectively, and investigated for the biological ...and sustainable control of yellow, or stripe rust, disease in wheat. The green synthesized NPs were characterized by UV-Visible spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and X-ray diffraction (XRD). The SeNPs and CeONPs, with different concentrations (i.e., 10, 20, 30, and 40 mg/L), were exogenously applied to wheat infected with
SeNPs and CeONPs, at a concentration of 30 mg/L, were found to be the most suitable concentrations, which reduced the disease severity and enhanced the morphological (plant height, root length, shoot length, leaf length, and ear length), physiological (chlorophyll and membrane stability index), biochemical (proline, phenolics and flavonoids) and antioxidant (SOD and POD) parameters. The antioxidant activity of SeNPs and CeONPs was also measured. For this purpose, different concentrations (50, 100, 150, 200 and 400 ppm) of both SeNPs and CeONPs were used. The concentration of 400 ppm most promoted the DPPH, ABTS and reducing power activity of both SeNPs and CeONPs. This study is considered the first biocompatible approach to evaluate the potential of green synthesized SeNPs and CeONPs to improve the health of yellow, or stripe rust, infected wheat plants and to provide an effective management strategy to inhibit the growth of
.
The present study aims to extract a natural reddish brown colorant from Peepal (
Ficus religiosa
) for silk dyeing using the microwave radiation process (MW). The colorant was isolated in aqueous and ...acidic media, and MW treatment for 1, 2, 3, 4, and 5 min has been given to both fabric and extract to observe changes in color intensity. The dye variables have been optimized, and for sustainable shade making process with good fastness, 1.0–5.0 g/100 mL of sustainable chemical and bio-mordants has been employed. It has been found that after microwave treatment for 3 min, under selected conditions, the irradiated aqueous extract has given high color intensity onto silk fabric. The utilization of 3% of Al, 4% of Fe, and 2% of tannic acid (T.A.) as pre chemical mordant whereas 4% of Al, 4% of Fe, and 3% of tannic acid as post chemical mordant have given good color characteristics. In comparison, 4% of acacia and 3% of turmeric and pomegranate while 3% of acacia and turmeric and 4% of pomegranate extracts as post-bio-mordant have given excellent color characteristics. It is concluded that MW treatment has an excellent sustainable efficacy to isolate colorant from Peepal bark for silk dyeing, whereas the inclusion of bio-mordants has not only made the process more sustainable and environmental friendly but also best K/S, and
L*a*b*
values have been acquired.
Bottom ash from coal-fired power plants is a potential raw material for the production of ceramic tiles, bricks and blocks for various applications. In this work we are presenting a novel microwave ...method to utilize the bottom ash to produce thermal insulating bricks. Foam samples were prepared by microwave foaming of the mortar prepared by milling the bottom ash, sodium silicate and NaOH. The microwave foaming ability of different slurry compositions and the physical and mechanical properties of the foamed samples were evaluated. FTIR analysis reveals that the degree of geopolymerization increases with increasing fraction of sodium silicate. Foams with low bulk density, high porosity, low thermal conductivity and compressive strengths were obtained by this method. With varying the bottom ash to sodium silicate ratio, it is possible to modulate the physical and mechanical properties of the insulating bricks.
•Synthesized porous foams from bottom ash using novel microwave foaming method.•Foams with good physical properties and low thermal conductivities were prepared.•Foam properties can modulate by varying the bottom ash to sodium silicate ratio.
Polymer composites are an important class of materials widely being used for many applications. But the main concern of non-degradability and adverse environmental impact of the polymer matrices and ...the synthetic reinforcements have given forth the need of environmental-friendly polymer matrices and reinforcements used in them. An attempt of such kind is to use the natural plant fibres as the reinforcements that have no harmful impact on the environment and also, they are cost effective. With growing interest in natural fibres in recent years, a lot of work is being done in various directions, which need to be gathered up for a specific interest. So, the present article is an attempt to review and discuss the research works that have evaluated the natural plant fibres as reinforcements in polymer composites. Natural fibre composites show variation of properties such as fibre’s source, type and structure. Interfacial adhesion between the fibre and the matrix is the most important factor when tensile properties of natural fibre composites are under consideration. The interfacial strength can be improved by some chemical modification of fibre surface, which changes the adhesion between fibre and matrix. These features of natural fibres as compared to synthetic fibres are motivating manufacturers and the end users to switch to natural fibre-based products.
This study is focused on oxidative degradation of Methyl Orange, a common azo dye, catalyzed by nickel hydroxide in aqueous solution at 303, 313, 323, and 333 K. Sodium hypochlorite, sodium ...hydroxide, and nickel sulfate hexahydrate in distilled water were used as starting material for preparation of nickel hydroxide. Pyrex glass batch reactor was used to study the effect of various conditions such as temperature, concentration, agitation, and catalyst dose on catalytic degradation of Methyl Orange in aqueous medium. About 80% Methyl Orange was degraded in 120 min. Experimental data were subjected to kinetic analysis using CurveExpert software. Degradation reaction was taking place according to Langmuir–Hinshelwood mechanism. According to this mechanism, the reactants adsorb at the surface of catalyst in first step followed by reaction between adsorbed reactants in second step. Adsorption of Methyl Orange on surface of catalyst followed Langmuir adsorption isotherm. Apparent activation energy, true activation energy, and heat of adsorption were determined as 13.2, 32.7 and –23.5 kJ mol−1, respectively.
•Natural soil can be used as precursor for geopolymer foams.•Better mechanical and environmental properties are achievable.•Optimum amounts of ingredients for optimum properties are ...evaluated.•Characterization of foams justifies the various valuable properties.
Thermal insulations are important in controlling the inner environment of the buildings. Geopolymer foams, also known as inorganic polymer foams, have attracted more attention among the inorganic class because of their sustainability and being environment friendly materials. In this research work natural soil based inorganic polymer foams have been successfully produced using low cost and abundantly available soil asaluminosilicate precursor. Samples with varying amounts of soil and liquid contents (NaOH and Na2SiO3 as alkaline activator solution) were used to prepare foams where hydrogen peroxide was used as foaming agent. The foamed slurries were poured into the molds and cured. The minimum thermal conductivity of 0.2670W/mK was achieved at bulk density of 0.8630gcm−3, total porosity of 63.1% and compressive strength of 2.41MPa for inorganic polymer foam containing 70% soil and 30% liquid composition. The highest compressive strength was achieved at 74% soil and 26% liquid composition. These properties were related to degree of inorganic polymerization using XRD and FTIR analyses. These foam materials can potentially be used as building thermal insulations.
•Quick and superior properties are achieved in fly ash based geopolymers by in-situ carbonation.•In-situ production of CO2 induces dehydroxylation and mineral sequestration.•Carbonates also mobilize ...the Al3+ ions in the mortar which is essential for the geopolymerization process.•Higher strength is achieved with lower bulk density of 1.56g/cm3.•The carbonation effect is justified by different characterization techniques.
This research work investigates the effect of in-situ carbonation on the properties and geopolymerization of alkali-activated fly ash mortars. The mortars were prepared from fly ash, sodium silicate, sodium hydroxide and different amounts of sodium bicarbonate. CO2 produced by the decomposition of sodium bicarbonate during curing, was utilized for the fast and improved development of the geopolymer properties. After curing the samples were characterized by TGA-DTA, XRD, FT-IR and SEM in order to understand the effect of carbonation on the thermal behavior, phase composition, degree of polymerization and microstructure of samples. Geopolymers with 2wt% of sodium bicarbonate shows higher compressive strength and Young’s modulus compared to the sample without sodium bicarbonate. The thermal conductivity was found higher for carbonated geopolymer, whereas samples without carbonation show least conductivity.
