Enhanced degradation of 2,4-dichlorphenoxyacetic acid herbicide by CaO2 activated by Fe(II) and ultrasound irradiation: Practical insight and mineralization

Eslami Akbar,Mahdipour Fayyaz,Maleksari Hajar Sharifi,Varank Gamze,Ghasemi Seyed Mehdi,Nejatian Parisa,Bagheri Amin,Madihi-Bidgoli Soheila 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.12

CaO2 was activated by Fe(II) and ultrasound (US) irradiation to degrade 2,4-dichlorphenoxyacetic acid (2,4-D) for the first time. Among transition metals (Fe, Cu, Mn and Co), Fe(II) had the best performance for the activation of CaO2. The impact of pH, CaO2 and Fe(II) concentration was studied, and under optimal situation ∼91% of 2,4-D was degraded during 60 min reaction time. The quenching experiments showed that the hydroxyl radical was the main factor for the destruction of 2,4-D while superoxide anions had a minor role. The bicarbonate ions and acid humic exhibited a strong inhibitory effect on the performance of CaO2/US/Fe(II) process. Carbon and chlorine mineralization of 2,4-D degradation was investigated; around 41% of C and 35% of Cl were mineralized during 60 min reaction time. The function of CaO2/US/Fe(II) process was studied on real drainage and other organic pollutants, and the results showed that the CaO2/US/Fe(II) process can be practical for water treatment. Finally, intermediates of 2,4-D degradation were identified, a pathway was proposed, and the toxicity of intermediates was assessed by ECOSAR software.

Nanostructured Hydroxyapatite for Biomedical Applications: From Powder to Bioceramic

Eslami, Hossein,Tahriri, Mohammadreza,Moztarzadeh, Fathollah,Bader, Rizwan,Tayebi, Lobat The Korean Ceramic Society 2018 한국세라믹학회지 Vol.55 No.6

In this study, a wet chemical method was used to synthesize nanostructured hydroxyapatite for biomedical applications. Diammonium hydrogen phosphate and calcium nitrate 4-hydrate were used as starting materials with a sodium hydroxide solution as an agent for pH adjustment. Scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, differential thermal analysis, thermal gravimetric analysis, atomic absorption spectroscopy, and ethylenediaminetetraacetic acid (EDTA) titration analysis were used to characterize the synthesized powders. Having been uniaxially pressed, the powders formed a disk-like shape. The sinterability and electrical properties of the samples were examined, and the three-point bending test allowed for the measurement of their mechanical properties. Sedimentation analysis was used to analyze the slurry ability of hydroxyapatite. As in-vitro biological properties of the samples, biocompatibility and cytotoxicity were assessed using osteoblast-like cells and the L929 cell line, respectively. Solubility was assessed by employing a simulated body fluid.

Integrated enhanced Raman scattering: a review

Eslami Sahand,Palomba Stefano 나노기술연구협의회 2021 Nano Convergence Vol.8 No.41

The demand for effective, real-time environmental monitoring and for customized point-of-care (PoC) health, requires the ability to detect low molecular concentrations, using portable, reliable and cost-effective devices. However, traditional techniques often require time consuming, highly technical and laborious sample preparations, as well as expensive, slow and bulky instrumentation that needs to be supervised by laboratory technicians. Consequently, fast, compact, self-sufficient, reusable and cost-effective lab-on-a-chip (LOC) devices, which can perform all the required tasks and can then upload the data to portable devices, would revolutionize any mobile sensing application by bringing the testing device to the field or to the patient. Integrated enhanced Raman scattering devices are the most promising platform to accomplish this vision and to become the basic architecture for future universal molecular sensors and hence an artificial optical nose. Here we are reviewing the latest theoretical and experimental work along this direction.

A modified binary version of aphid–ant mutualism for feature selection: a COVID-19 case study

Eslami N,Yazdani S,Mirzaei M,Hadavandi E 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.2

The speedy development of intelligent technologies and gadgets has led to a drastic increment of dimensions within the datasets in recent years. Dimension reduction algorithms, such as feature selection methods, are crucial to resolving this obstacle. Currently, metaheuristic algorithms have been extensively used in feature selection tasks due to their acceptable computational cost and performance. In this article, a binary-modified version of aphid–ant mutualism (AAM) called binary aphid–ant mutualism (BAAM) is introduced to solve the feature selection problems. Like AAM, in BAAM, the intensification and diversification mechanisms are modeled via the intercommunication of aphids with other colonies’ members, including aphids and ants. However, unlike AAM, the number of colonies’ members can change in each iteration based on the attraction power of their leaders. Moreover, the second- and third-best individuals can take the place of the ringleader and lead the pioneer colony. Also, to maintain the population diversity, prevent premature convergence, and facilitate information sharing between individuals of colonies including aphids and ants, a random cross-over operator is utilized in BAAM. The proposed BAAM is compared with five other feature selection algorithms using several evaluation metrics. Twelve medical and nine non-medical benchmark datasets with different numbers of features, instances, and classes from the University of California, Irvine and Arizona State University repositories are considered for all the experiments. Moreover, a coronavirus disease (COVID-19) dataset is used to validate the effectiveness of the BAAM in real-world applications. Based on the acquired outcomes, the proposed BAAM outperformed other comparative methods in terms of classification accuracy using various classifiers, including K nearest neighbor, kernel-based extreme learning machine, and multi-class support vector machine, choosing the most informative features, the best and mean fitness values and convergence speed in most cases. As an instance, in the COVID-19 dataset, BAAM achieved 96.53% average accuracy and selected the most informative feature subset.

Interference Analysis in an Urban Mesh Network Operating in the 60-GHz Band

Maryam Eslami Rasekh,Forouhar Farzaneh 한국전자통신연구원 2013 ETRI Journal Vol.35 No.5

Because of their exclusive features, millimeter wave directive mesh networks can be considered for small cell backhaul support in urban environments. For this purpose, a network of closely spaced stations has been considered with very directive line-of-sight links operating in the 60-GHz band. An attempt is made to evaluate channel response and interference behavior in such a network, taking into account the effect of building blockage. A simple grid of building blocks is considered as the propagation environment, and wave propagation is simulated using 2.5-dimensional (2.5D) ray tracing (2D with ground effect) to calculate the received signal at different nodes in the network. The results are compared with free space predictions and used to evaluate interference at all nodes in the channel and describe certain characteristics of links, such as the delay profile and the correlation length.

Free vibration analysis of corroded steel plates

Alireza Eslami-majd,Ahmad Rahbar-Ranji 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.6

Vibration analysis of unstiffened/stiffened plates has long been studied due to its importance in the design and condition assessmentsof ship and offshore structures. Corrosion is inevitable in steel structures and has been so far considered in strength analysis of structures. We studied the free vibration of pitted corroded plates with simply supported boundary conditions. Finite element analysis, withABAQUS, was used to determine the natural frequencies and mode shapes of corroded plates. Influential parameters including plateaspect ratio, degree of pit, one-sided/both-sided corroded plate, and different corrosion patterns were investigated. By increasing the degreeof corrosion, reduction of natural frequency increases. Plate aspect ratio and plate dimensions have no influence on reduction ofnatural frequency. Different corrosion patterns on the surface of one-sided corroded plates have little influence on reduction of naturalfrequency. Ratio of pit depth over plate thickness has no influence on the reduction of natural frequency. The reduction of natural frequencyin both-sided corroded plates is higher than one-sided corroded plates with the same amount of total corrosion loss. Mode shapesof vibration would change due to corrosion, except square mode shapes.

Blast response of corroded steel plates

Alireza Eslami-majd,Ahmad Rahbar-Ranji 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.5

Numerical results for one- and both-sided corroded steel plates subjected to blast loading are presented. Finite element analysis, withABAQUS software, is employed to determine the deformation and stress distributions. The results for the case of triangular pulse pressureon un-corroded plates are validated against literature-based data and then, detailed parametric studies are carried-out. The effects ofinfluential parameters including, plate aspect ratio, degree of pit and different ratio of pit depth at each sides of the plate are investigated. The results show that position of pitted surface in respect to applied pressure is the most influential parameter on reduction of dynamicload carrying capacity of pitted plates. By increasing degree of pitting, reduction of dynamic load carrying capacity decrease more.

Mechanism of Elasto-Plastic Behavior of Composite Beam Connected to RHS Column

Mohammadreza Eslami,Hisashi Namba 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.3

Following to the experimental test of full-scale beam-to-RHS column sub-assemblies, it was observed that in the composite beam considerable reduction of rotation capacity occurs due to the increase of strain at the lower flange. In the case of bare beam-to-RHS column connection, it is already known that occurrence of out-of-plane deformation in the column web, results in the reduction of rotation capacity of beam. However, in the composite beam-to-RHS column connection due to slab axial force, web connection is in more severe stress condition. Further comprehensive understanding of effect of out-of-plane deformation of RHS column on the behavior of composite beam is needed. In this paper results of finite element analysis and limit analysis are presented to clarify the structural condition of web connection. The force flow pattern and ultimate flexural capacity are evaluated by considering main parameters affecting the deformation. Correspondence between FEA, limit analysis and experimental data is shown, mechanism of mechanical stress transfer and strain concentration is explained.

Synthesis and characterization of nanocrystalline fluorinated hydroxyapatite powder by a modified wet-chemical process

Hossein Eslami,Mehran Solati-Hashjin,Mohammadreza Tahriri 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.3

Fluorinated hydroxyapatite (FHA; fluorhydroxyapatite) powder was synthesized through a pH-cycling method by varying the sodium fluoride [NaF] concentration in a hydroxyapatite suspension as a modified wet-chemical process. The powder sample was characterized by the commonly used bulk techniques of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), F-selective electrode, atomic absorption spectroscopy (AAS) and EDTA titration analyses. SEM was used to estimate the particles size of the powder and observe the morphology and agglomeration state of the powder. The functional groups presented in the synthesized powder were ascertained by FTIR investigations. AAS and EDTA titration techniques were employed for calculation of the Ca/P molar ratio. F-selective electrode analysis also was used to measure the fluorine (F) content in the crystalline network of the synthesized powder. Finally, the FHA and other phases according to processing parameters were observed by XRD analysis Fluorinated hydroxyapatite (FHA; fluorhydroxyapatite) powder was synthesized through a pH-cycling method by varying the sodium fluoride [NaF] concentration in a hydroxyapatite suspension as a modified wet-chemical process. The powder sample was characterized by the commonly used bulk techniques of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), F-selective electrode, atomic absorption spectroscopy (AAS) and EDTA titration analyses. SEM was used to estimate the particles size of the powder and observe the morphology and agglomeration state of the powder. The functional groups presented in the synthesized powder were ascertained by FTIR investigations. AAS and EDTA titration techniques were employed for calculation of the Ca/P molar ratio. F-selective electrode analysis also was used to measure the fluorine (F) content in the crystalline network of the synthesized powder. Finally, the FHA and other phases according to processing parameters were observed by XRD analysis

A 3D mathematical evaluation of the emission into the air of reactive BTEX compounds: A new approach for mechanism reduction

Nesarak Eslami,Esmaeil Fatehifar,Mohammad Ali Kaynejad 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.6

BTEX species are abundant volatile organic compounds that are classified as main pollutants by several environmental protection agencies. In this study, a new 3D air pollution dispersion model with the capability of taking into account the BTEX"s reactions was developed and evaluated. The Toxchem model is employed to estimate the amount of emitted BTEX from several area sources, followed by simulating the transport of the reactive species through a 3D model. Also, reduced mechanisms were developed, based on Master Chemical Mechanism (MCM), for the simulation of the atmospheric chemistry of BTEX. The application of the mechanism reduction method yielded a mechanism of 43 species and 45 reactions. Based on findings, the deviation of the reduced mechanism from the whole mechanism was < 4% throughout the simulation. In addition, the result showed that, during a 12 h period of simulation, the effect of the atmospheric chemical reaction on reducing the final concentration of benzene, toluene, ethylbenzene, m-xylene, o-xylene, and p-xylene was about 0.3, 1, 1.4, 5, 3.1, and 3.2%, respectively. Lastly, it was indicated that the estimated emission rates by Toxchem and simulated concentrations by the dispersion model were in good agreement with the reported experimental values.