42 research outputs found

    Degradation of phenol using US/periodate/nZVI system from aqueous solutions

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    In the present work, the degradation of phenol from aqueous solutions was investigated using periodate/zero valent iron nanoparticle (nZVI) in the presence of ultrasound at a batch reactor. The Experimental tests were carried out using pre-designated concentrations of nZVI, periodate, and pH ranging from 1-7 mM, 0.5-5 mM, 3-11 respectively. During the all experimental tests the ultrasonic reactor was operated at a fix frequency (40 kHz), temperature (33±1) and power (350 W). The results of nZVI/periodate/ultrasound system on degradation of phenol showed that the removal efficiency was indeed affected by the amount of free radicals produced to initiate the oxidative decomposition of phenol. also, by increasing the nZVI loading to 3 mM and periodate concentration to 3 mM, the efficiency of phenol removal was increased. Besides, the acidic pH (pH = 3) was found to be more effective than neutral and alkaline pH in degradation of phenol. © 2019 Global NEST Printed in Greece. All rights reserved

    Data on using macro invertebrates to investigate the biological integrity of permanent streams located in a semi-arid region

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    Abstract The aquatic ecosystems are continuously endangered due to variety of hazardous chemicals containing different toxic agents which can be emitted from anthropogenic sources. Besides the increasing of human population, various kinds of contaminants enter into the surface water resources. The aim of the present study was to investigate the abundance and diversity of macro invertebrates in two permanent streams located in the northern part of Tehran. The biological integrity of the streams was determined by manual sampling approach at five points. The distances between the sampling points were at least 2 km. The bio indicator organisms, organic pollution, and dissolved oxygen were measured. The different types of benthic invertebrates such as riffle beetle, midge and caddish fly larvae, dragon fly, may fly and stone fly nymph, riffle beetle adult, pyralid caterpillar, leech, and pouch snail were identified. It can be concluded that, the identified benthic macro invertebrates can be served as appropriate biological indicator in the studied area. Keywords Biological integrity Tehran Macro invertebrate

    Artificial neural network (ANN) approach for modelling of pile settlement of open-ended steel piles subjected to compression load

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    This study was devoted to examine pile bearing capacity and to provide a reliable model to simulate pile load-settlement behaviour using a new artificial neural network (ANN) method. To achieve the planned aim, experimental pile load test were carried out on model open-ended steel piles, with pile aspect ratios of 12, 17, and 25. An optimised second-order Levenberg-Marquardt (LM) training algorithm has been used in this process. The piles were driven in three sand densities; dense, medium, and loose. A statistical analysis test was conducted to explore the relative importance and the statistical contribution (Beta and Sig) values of the independent variables on the model output. Pile effective length, pile flexural rigidity, applied load, sand-pile friction angle and pile aspect ratio have been identified to be the most effective parameters on model output. To demonstrate the effectiveness of the proposed algorithm, a graphical comparison was performed between the implemented algorithm and the most conventional pile capacity design approaches. The proficiency metric indicators demonstrated an outstanding agreement between the measured and predicted pile-load settlement, thus yielding a correlation coefficient (R) and root mean square error (RMSE) of 0.99, 0.043 respectively, with a relatively insignificant mean square error level (MSE) of 0.0019. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group

    The Submodule-Based Zero-Divisor Graph with Respect to Some Homomorphism

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    Let M be an R-module and 0 6= f ∈ M∗ = Hom(M, R). The graph Γf (M) is a graph with vertices Z f (M) = {x ∈ M \ {0} | xf(y) = 0 or yf(x) = 0 for some non-zero y ∈ M}, in which non-zero elements x and y are adjacent provided that xf(y) = 0 or yf(x) = 0, which introduced and studied in [3]. In this paper we associate an undirected submodule based graph Γf N (M) for each submodule N of M with vertices Z f N (M) = {x ∈ M \ N | xf(y) ∈ N or yf(x) ∈ N for some y ∈ M \ N}, in which non-zero elements x and y are adjacent provided that xf(y) ∈ N or yf(x) ∈ N. We observe that over a commutative ring R, Γ f N (M) is connected and diam(Γf N (M)) 6 3. Also we get some results about clique number and connectivity number of Γf N (M
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