797 research outputs found

    Face antimgaic labeling of double duplication for some special graphs

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    The main objective of the paper is to determine (a, d)− face antimagic labeling for the double duplication of all vertices by edges of ladder, tadpole and m-copies of path graphs. Also, if a graph G is (a, d)− face antimagic except for 3-sided faces then the double duplication of all vertices by edges of a graph G is also (a,d)-face antimagic.Publisher's Versio

    Nonlocal state-space strain gradient wave propagation of magneto thermo piezoelectric functionally graded nanobeam

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    In this work, the state -space nonlocal strain gradient theory is used for the vibration analysis of magneto thermo piezoelectric functionally graded material (FGM) nanobeam. An analysis of FGM constituent properties is stated by using the power law relations. The refined higher order beam theory and Hamilton's principle have been used to obtain the motion equations. Besides, the governing equations of the magneto thermo piezoelectric nanobeam are extracted by developed nonlocal state-space theory. And to solve the wave propagation problems, the analytical wave dispersion method is used. The effect of magnetic potential, temperature gradient, and electric voltage in variant parameters are presented in graph

    Optimization of NaCl based spray corrosion test process parameters of heat treated hybrid metal matrix composites

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    ABSTRACT. Aluminium hybrid metal matrix composites (AHMMCs) have widely employed in aerospace, transportation, and automotive applications since for their excellent mechanical qualities and high corrosion resistance. In this research, Al8079 is selected as a matrix material. The titanium diboride (TiB2) is selected as hard reinforcement and molybdenum disulfide (MoS2) is used as soft reinforcement. The Al8079/15 wt.% TiB2/x wt.% MoS2 (x = 0, 2.5, 5 and 7.5) HMMCs are fabricated by using stir casting. The composites are heat treated under T6 condition. The density and micro hardness tests are conducted. The optimization on NaCl based spray corrosion test process parameters is done using grey relational analysis (GRA). The selected input process parameters are Al8079/15 wt.% TiB2/wt.% MoS2 (x = 0, 2.5 and 5), pH value of NaCl solution (x = 6, 9 and 12), hang time (x = 24, 48, and 72 h) and pressure (x = 0.7, 0.9 and 1.1 kg/cm2). The selected response parameters are micro hardness, mass loss and wear loss. The L9 Taguchi design is used for optimization. The wear test is conducted at the constant speed of 0.5 m/s, loading rate of 20 N and the sliding distance of 1000 m. The percentage of improvement of GRG from initial setting to experimental is 10.4%.   KEY WORDS: Reinforcement, Stir casting, Optimization, GRA, NaCl Bull. Chem. Soc. Ethiop. 2022, 36(4), 903-914.                                                         DOI: https://dx.doi.org/10.4314/bcse.v36i4.1

    Grey Relational Analysis-Based Optimisation of Input Parameters of Incremental Forming Process Applied to the AA6061 Alloy

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    Incremental forming is mainly based on the deformation occurring locally on sheet metal. A hemispherical head tool deforms the sheet metal progressively, and its path is controlled by means of a CNC machine. Even though the process is a time-consuming one, the cost reduction connected with punches and dies makes this process attractive for rapid prototyping. In single point incremental forming, the quality of formability mainly depends on the forming parameters and the tool path generated. In this study, cone-shaped components were formed from AA6061 alloy sheets with a thickness of 1.15 mm. Factors, such as feed rate, spindle speed, and step depth are considered as input parameters to determine the output response in terms of surface roughness and wall thickness. Taguchi’s technique was used for conducting the experiments with the smallest number of repetitions to evaluate the output. Grey relational analysis was introduced to determine the optimal forming parameters with respect to the output response. The experiments conducted with the optimised parameters show a minimal deviation of 0.15% in the grade value compared to the predicted grade which is acceptable

    FTIR and XRD studies on some archaeological artifacts from Bohn, India

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              Spectroscopic studies have been performed on archaeological pottery samples from Bhon in Maharashtra. The clay mineral type and its structural deformation due to firing have been studied from their Fourier Transform Infrared (FTIR) spectra. The maximum firing temperature attained during baking, firing conditions (open/reduced atmosphere) and iron mineral phase changes are well established. X-ray diffraction (XRD) studies on archaeological artifacts pave the way to identify the minerals

    Enhanced removal of nitrate in an integrated electrochemical-adsorption system

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    © 2017 Elsevier B.V. The electrochemical (EC) method of removing pollutants in water is a widely used process in water and wastewater treatment. An EC-adsorption integrated system was investigated to test whether the simultaneous removal of nitrate by the two processes would be better than removal utilising the individual EC and adsorption methods. In the integrated system, an adsorbent (ion exchange resin - Dowex 21k XLT) was placed inside a stainless steel box that served as an anode with a Cu plate as cathode. In an experiment using 2 L nitrate solution containing 20 mg N/L and 2 g adsorbent the rate of nitrate removal in the integrated system was initially fast with 35% removed in 30 min, though slowing down later. The rate of removal increased with increasing current, voltage and pH up to 7 but decreased as the distance between the electrodes also increased. The optimum nitrate removal of 67% was obtained at pH 7, 1 A, and 31 V for a distance of 1 cm between the electrodes after 180 min. The amount of nitrate removed fell when sulphate was present in the integrated system due to sulphate competing with nitrate for adsorption. Concentration of ammonium produced by nitrate reduction in the EC system was reduced in the presence of adsorbent. Nitrate removal in the integrated system is approximately equal to the sum of the removals in the two individual processes

    Antioxidant and Antiproliferative Effect of Pleurotus ostreatus

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    In this study, ethanol extract of an edible mushroom Pleurotus ostreatus cultivated under the laboratory condition was investigated for its antioxidant and anticancer property in vitro. To confirm the total antioxidant activity, ABTS, DPPH free radical-scavenging assay was carried, along with total phenolic and flavonoid concentration. The ethanolic extract showed a potent antioxidant activity against both DPPH and ABTS radicals, with the EC50 value of 0.202±0.55 mg/mL and 6.42±0.261 mg/mL. Antioxidant components like total flavonoids were 1.82±0.15 µg/mg (Quercetin equivalent) and the total phenols were 8.52±0.6 mg/g (Catechin equivalent). Against the cancer cell (HL-60) in vitro P. ostreatus extracts exhibited the cytotoxic effect. The HL-60 cells treated with ethanol extract was further stained with propidium iodide and analyzed through flow cytometry, to identify whether the cytotoxicity induction was due to apoptosis or necrocis. The results of the flow cytometry confirm the cytotoxic effect of the mushroom extract was found to be mediated by the induction of apoptosis. In conclusion, our results supported the consumption of edible mushroom that act as a good dietary supplement and functional food

    Simultaneous adsorption of Cd, Cr, Cu, Pb, and Zn by an iron-coated Australian zeolite in batch and fixed-bed column studies

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    © 2015 Elsevier B.V. Excessive levels of heavy metals in water are an environmental hazard. An Australian zeolite with (ICZ) and without (Z) iron-coating, was used to remove five heavy metals from aqueous solutions using adsorption in batch and column experiments. The batch study showed that the Langmuir adsorption capacities of heavy metals on Z and ICZ at pH 6.5 and ionic strength 10-3M NaNO3 were in the order Pb>Cu>Cd>Cr, Zn for single metal (5.0-11.2mg/g) and for mixed metals solution (3.7-7.6mg/g). The data for the kinetics of adsorption satisfactory fitted to both the pseudo-first and second order models with fits slightly better for the latter model. Data fitted to a diffusion model revealed that adsorption took place in two or more than two different stages: a fast external surface adsorption, and a gradual adsorption controlled by both film diffusion and intra-particle diffusion. The column adsorption data were fairly well described by Thomas model, with the order of Thomas adsorption capacity following a similar trend as in the batch study. In both batch and column experiments, the adsorption capacities were higher for ICZ than for Z and were generally lower in mixed metals system than in single metals system. Leaching of used ICZ columns with 0.1M HCl, resulted in 64-93% of adsorbed metals being desorbed, and 10% of Fe being dissolved from the ICZ

    Computational analysis of third-grade liquid flow with cross diffusion effects: application to entropy modeling

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    The key goal of this current study is to analyze the entropy generation with cross diffusion effects. The third-grade type non-Newtonian fluid model is used in this study. The current flow problem is modelled with stretching plate. Modified Fourier heat flux is replaced the classical heat flux. The appropriate transformation is availed to convert the basic boundary layers equations into ODEs and then verified by homotopy algorithm. The consequences of various physical quantities on temperature, velocity, entropy and concentration profile are illustrated graphically
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