Amol University of Special Modern TechnologiesCaspian Journal of Engineering Modern Technologies3060-57091120240601A Model Based on LCAO Theory to Evaluate the Dispersion Equation of Carbon Nanotubes16196684ENRobertoMaraniInstitute of Intelligent Industrial Technologies and Systems for Advanced Manufacturing (STIIMA), National Research Council of Italy, 70125, Bari, ItalyAnna GinaPerriElectronic Devices Laboratory, Department of Electrical and Information Engineering, Polytechnic University of Bari, 70126, Bari, Italy0000-0003-4949-987XJournal Article20230530<em>In this paper we propose a model to evaluate the dispersion relationship of Carbon Nanotubes. The model is based on the application to band-structure calculation of both of them the tight-binding approximation and the theory of Linear Combination of Atomic Orbitals (LCAO), obtaining a reduction of computational time compared to other methods proposed in literature, </em><em>without losing in accuracy</em><em>.</em>https://cjemt.ausmt.ac.ir/article_196684_9ed1097417d7894e322238b24daee3a2.pdfAmol University of Special Modern TechnologiesCaspian Journal of Engineering Modern Technologies3060-57091120240601Facilitated Method for Production of Chitin and Chitosan from Shrimp Shells713196686ENAmir Mohammad -Danesh PajoohBioceramic and Implant Specialized Laboratory, Department of Life Science
Engineering, Collage of Interdisciplinary Science and Technology,
University of Tehran, Tehran, IranZahra -MohammadiBioceramic and Implant Specialized Laboratory, Department of Life Science
Engineering, Collage of Interdisciplinary Science and Technology,
University of Tehran, Tehran, IranJournal Article20230720<em>Chitin and its valuable derivative chitosan offer a set of unique properties: biocompatibility, biodegradability for harmless products, non-toxicity, physiological inertness, etc. The main resources exploited are two marine crustaceans; shrimp and crab. In the present study, our aim is to produce chitin and chitosan and compare their properties with commercial properties. Due to the possibility of industrial and mass production, pre-purification methods were used to produce standard chitin and chitosan. In this regard, after the treatment of the shrimp, their shells were further cleaned and facilitated for the processes of demineralization, deproteinization, and deacetylation. Deproteinization was done with 1 M of sodium hydroxide and demineralized with 1%, 2%, 3%, 4% and 5% of hydrochloric acid, respectively. The novelty of this work is comparing different concentrations of HCl to choose the best concentration for the production of chitin and chitosan. This method showed the high purity of chitin and chitosan with less than 1% protein residue along with high molecular weight and high crystallinity. The produced chitin and chitosan were characterized by FTIR and XRD analyses. It was found that the surface morphology of chitin increases with increasing acid concentration. According to our study, the best degree of deacetylation (%DD) was 88.76 %. This modified approach has the potential for large-scale production due to ease of operation and reduced environmental issues.</em>https://cjemt.ausmt.ac.ir/article_196686_fa14c66b48455bb1a212fa54ac240cda.pdfAmol University of Special Modern TechnologiesCaspian Journal of Engineering Modern Technologies3060-57091120240601Analysis and Design of Photonic Band Gap Devices: A Review1533196685ENRobertoMaraniInstitute of Intelligent Industrial Technologies and Systems for Advanced Manufacturing (STIIMA), National Research Council of Italy, 70125, Bari, ItalyAnna GinaPerriElectronic Devices Laboratory, Department of Electrical and Information Engineering, Polytechnic University of Bari, 70126, Bari, Italy0000-0003-4949-987XJournal Article20230711<em>Photonic BandGap (PBG) crystals are able to overcome the typical integration limits of traditional optical circuits, allowing a scale of integration similar to the electronic ULSI. According to their geometrical characteristics, photonic crystals inhibit the light propagation in one or more directions, depending on the working frequency: if so, a band gap exists, i.e. a frequency range in which the wave cannot propagate. Moreover, the introduction of defects inside the periodical structure of a photonic crystal determines the forming of photonic states located in the gap. In this paper, after a brief description of operation principle of photonic crystals, we present a review of the most important photonic crystals devices, describing, in particular, the main steps required to model and design resonant cavities and particle accelerators.</em>https://cjemt.ausmt.ac.ir/article_196685_e2da40ee5e79774695c4d09ece49aea0.pdfAmol University of Special Modern TechnologiesCaspian Journal of Engineering Modern Technologies3060-57091120240601Fabrication of Low-Cost Superhydrophobic Coating on Low-Carbon Steel Using Liquid Flame Spray3544196682ENMohammadAbolhassan AraghiMechanical Engineering, University of Tehran, Tehran, IranSeyed FarshidChiniMechanical Engineering, University of Tehran, Tehran, IranJournal Article20230519<em>A nano-engineered superhydrophobic coating was fabricated using a two-step and low-cost method employing a liquid oxy-acetylene flame spray mechanism on mild A516 steel. Oxygen and acetylene were used as flammable gases. Nanostructured coating is obtained by flame spraying aluminum nitrate solved in ethanol on the substrate. To lower the surface energy, Perfluorodecyltriethoxysilane [PFDTES] and silicone elastomer were used. Results revealed that the wettability of the surface strongly depends on the precursor concentration so that at 3.5% concentration of aluminum nitrate in ethanol, maximum contact angle [157°] occurs. The distance between the substrate and nozzle is another key parameter to control and it directly affects the contact angle. Sandpaper abrasion test showed outstanding mechanical durability so that the coating maintained in hydrophobicity range under the load of 100 grams of weight and moving 10 cm on sandpaper 1000 grit for 8 cycles. The parameters affecting the process were thoroughly analyzed according to the applied liquid flame spray mechanism and the appropriate performance range of each was obtained that According to the experiments, the precursor flowrate and the distance between the substrate and nozzle should be repectively 0.9-1.9 ml/min and 14-22 cm.</em>https://cjemt.ausmt.ac.ir/article_196682_d401d9564e69f4bd38e86c87a7c518ce.pdfAmol University of Special Modern TechnologiesCaspian Journal of Engineering Modern Technologies3060-57091120240601Study of Electronic Properties of Carbon Nanotubes: A Review4561196687ENRobertoMaraniInstitute of Intelligent Industrial Technologies and Systems for Advanced Manufacturing (STIIMA), National Research Council of Italy, 70125, Bari, ItalyAnna GinaPerriElectronic Devices Laboratory, Department of Electrical and Information Engineering, Polytechnic University of Bari, 70126, Bari, Italy0000-0003-4949-987XJournal Article20230528<em>In this review we first examine the main issues of nanotechnology. In particular, in the broad scenario of nanoscale devices, we present a detailed study of Carbon Nanotubes (CNTs), which arouse a growing interest for their unique properties and their versatility. </em><em>We study and characterize the electronic properties of carbon nanotubes through the determination of the relationship between structure and electronic characteristics of CNTs.</em>https://cjemt.ausmt.ac.ir/article_196687_fd558efee626b8d7c6f327062610c1cf.pdfAmol University of Special Modern TechnologiesCaspian Journal of Engineering Modern Technologies3060-57091120240601Backward Defect States in One with Dispersive Left-Handed Material Defect6368196683ENBehnamKazempourDepartment of physics, Ahar Branch, Islamic Azad University, Ahar, IranJournal Article20230515<em>We present a theoretical study of electromagnetic defect states localized at a defect layer with left-handed (LH) material between two symmetric semi-infinite one-dimensional photonic crystals (1DPCs) composed of right-handed (RH) materials. We consider magnetic permeability and electric permittivity of LH layer being dispersive. An analytical direct matching procedure within the Kronig-Penney model was applied to analyze the dispersion properties of the localized defect states. It is shown that the dispersive LH layer act as an effective tool to tune the type of defect modes from backward to forward and vice versa and it plays an important role on the localization of them, when the frequency and the parameters of the defect layer vary. Also, we show that when the LH layers are chosen dispersive, three types of dispersion: positive, zero, and negative dispersion of defect waves are obtained in a wide range of radiation angle and frequency, which is depending on the physical and optical parameters of the defect layer.</em>https://cjemt.ausmt.ac.ir/article_196683_b0d574ca2e7b53985738ba72ad65f684.pdf