Search results for: inductively coupled plasma optical emission spectroscopy(icp-oes)

Authors: Andrey V. Timofeev

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This paper presents development results of the method of seismoacoustic activity monitoring based on usage vibrosensitive properties of optical fibers. Analysis of Rayleigh backscattering radiation parameters changes, which take place due to microscopic seismoacoustic impacts on the optical fiber, allows to determine seismoacoustic emission sources positions and to identify their types. Results of using this approach are successful for complex monitoring of railways.

Keywords: C-OTDR systems, monitoring of railways, Rayleigh backscattering, eismoacoustic activity

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Authors: Abu Harera Nadeem, Kingsley Donkor

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Tea is a popular beverage due to its flavour, aroma and antioxidant properties—with the most consumed varieties being green and black tea. Antioxidants in tea can lower the risk of Alzheimer’s and heart disease and obesity. However, these teas contain heavy metals such as Hg, Cd, or Pb, which can cause autoimmune diseases like Graves disease. In this study, 11 heavy metals in various commercial green, black, and oolong tea samples were determined using inductively coupled plasma-mass spectrometry (ICP-MS). Two methods of sample preparation were compared for accuracy and precision, which were microwave-assisted digestion and ultrasonic-assisted extraction. The developed method was further validated by detection limit, precision, and accuracy. Results showed that the proposed method was highly sensitive with detection limits within parts-per-billion levels. Reasonable method accuracy was obtained by spiked experiments. The findings of this study can be used to delve into the link between tea consumption and disease and to provide information for future studies on metal determination in tea.

Keywords: ICP-MS, green tea, black tea, microwave-assisted acid digestion, ultrasound-assisted extraction

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Authors: K. Abbas, R. Ahmad, I. A. Khan, S. Saleem, U. Ikhlaq

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Nitriding of p-type Si samples by pulsed DC glow discharge is carried out for different Ar concentrations (30% to 90%) in nitrogen-argon plasma whereas the other parameters like pressure (2 mbar), treatment time (4 hr) and power (175 W) are kept constant. The phase identification, crystal structure, crystallinity, chemical composition, surface morphology and topography of the nitrided layer are studied using X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), optical microscopy (OM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) respectively. The XRD patterns reveal the development of different diffraction planes of Si₃N₄ confirming the formation of polycrystalline layer. FTIR spectrum confirms the formation of bond between Si and N. Results reveal that addition of Ar into N₂ plasma plays an important role to enhance the production of active species which facilitate the nitrogen diffusion.

Keywords: crystallinity, glow discharge, nitriding, sputtering

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Authors: Lloyd G. Allred

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The distribution of velocities of particles in plasma is a well understood discipline of plasma physics. Boltzmann’s law and the Maxwell-Boltzmann distribution describe the distribution of velocity of a particle in plasma as a function of mass and temperature. Particles with the same mass tend to have the same velocity. By expressing the same law in terms of energy alone, the author obtains a distribution independent of mass. In summary, for particles in plasma, the energies tend to equalize, independent of the masses of the individual particles. For high-energy plasma, the original law predicts velocities greater than the speed of light. If one uses Einstein’s formula for energy (E=mc²), then a relativistic correction is not required.

Keywords: cosmology, EMP, plasma physics, relativity

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Authors: Adewale Tolulope Irewale, Elias Emeka Elemike, Christian O. Dimkpa, Emeka Emmanuel Oguzie

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As the global population steadily approaches the 10billion mark, the world is currently faced with two major challenges among others – accessing sustainable and clean energy, and food security. Accessing cleaner and sustainable energy sources to drive global economy and technological advancement, and feeding the teeming human population require sustainable, innovative, and smart solutions. To solve the food production problem, producers have relied on fertilizers as a way of improving crop productivity. Commercial inorganic fertilizers, which is employed to boost agricultural food production, however, pose significant ecological sustainability and economic problems including soil and water pollution, reduced input efficiency, development of highly resistant weeds, micronutrient deficiency, soil degradation, and increased soil toxicity. These ecological and sustainability concerns have raised uncertainties about the continued effectiveness of conventional fertilizers. With the application of nanotechnology, plant biomass upcycling offers several advantages in greener energy production and sustainable agriculture through reduction of environmental pollution, increasing soil microbial activity, recycling carbon thereby reducing GHG emission, and so forth. This innovative technology has the potential for a circular economy and creating a sustainable agricultural practice. Nanomaterials have the potential to greatly enhance the quality and nutrient composition of organic biomass which in turn, allows for the conversion of biomass into nanofertilizers that are potentially more efficient. Water hyacinth plant harvested from an inland water at Warri, Delta State Nigeria were air-dried and milled into powder form. The dry biomass were used to prepare biochar at a pre-determined temperature in an oxygen deficient atmosphere. Physicochemical analysis of the resulting biochar was carried out to determine its porosity and general morphology using the Scanning Transmission Electron Microscopy (STEM). The functional groups (-COOH, -OH, -NH2, -CN, -C=O) were assessed using the Fourier Transform InfraRed Spectroscopy (FTIR) while the heavy metals (Cr, Cu, Fe, Pb, Mg, Mn) were analyzed using Inductively Coupled Plasma – Optical Emission Spectrometry (ICP-OES). Impregnation of the biochar with nanonutrients were achieved under varied conditions of pH, temperature, nanonutrient concentrations and resident time to achieve optimum adsorption. Adsorption and desorption studies were carried out on the resulting nanofertilizer to determine kinetics for the potential nutrients’ bio-availability to plants when used as green fertilizers. Water hyacinth (Eichhornia crassipes) which is an aggressively invasive aquatic plant known for its rapid growth and profusion is being examined in this research to harness its biomass as a sustainable feedstock to formulate functionalized nano-biochar fertilizers, offering various benefits including water hyacinth biomass upcycling, improved nutrient delivery to crops and aquatic ecosystem remediation. Altogether, this work aims to create output values in the three dimensions of environmental, economic, and social benefits.

Keywords: biochar-based nanofertilizers, eichhornia crassipes, greener agriculture, sustainable ecosystem, water hyacinth

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Authors: Zeenat Parveen, Ashiq Hussain

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This review paper consists of applications of PDMS (polydimethylsiloxane) materials for enhanced performance, optical fiber sensors in acousto-ultrasonic, mechanical measurements, current applications, sensing, measurements and interferometric optical fiber sensors. We will discuss the basic working principle of fiber optic sensing technology, various types of fiber optic and the PDMS as a coating material to increase the performance. Optical fiber sensing methods for detecting dynamic strain signals, including general sound and acoustic signals, high frequency signals i.e. ultrasonic/ultrasound, and other signals such as acoustic emission and impact induced dynamic strain. Optical fiber sensors have Industrial and civil engineering applications in mechanical measurements. Sometimes it requires different configurations and parameters of sensors. Optical fiber current sensors are based on Faraday Effect due to which we obtain better performance as compared to the conventional current transformer. Recent advancement and cost reduction has simulated interest in optical fiber sensing. Optical techniques are also implemented in material measurement. Fiber optic interferometers are used to sense various physical parameters including temperature, pressure and refractive index. There are four types of interferometers i.e. Fabry–perot, Mach-Zehnder, Michelson, and Sagnac. This paper also describes the future work of fiber optic sensors.

Keywords: fiber optic sensing, PDMS materials, acoustic, ultrasound, current sensor, mechanical measurements

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Authors: A. Lemzadmi

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Rotational and vibrational temperatures of the SF6-N2 gas mixture are spectroscopically measured over a pressure range of 2-14 bars. The spectra obtained of the light emission of the corona discharge were recorded with different values of pressure, voltage and current together with the variation of the position of the tip electrode. The emission of N2 is very dominant for different gas concentration and the second positive system 2S+ is the most important. The convolution method is used for the determination of the temperature. The Rotational temperature measurements of the plasma reveal gas temperatures in the range of 450-650°K and vibrational temperatures in the range of 1800-2200°K.

Keywords: rotational temperatures, corona discharges, SF6-N2 gas mixture, vibrational temperatures

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Authors: Nemes Alexandra

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The aim of the research is to develop an optimum microstructure of steel coatings on aluminum surfaces for application on the crankcase cylinder bores. For the proper design of the microstructure of the coat, it is important to control the plasma gun unit properly. The maximum operating time was determined while the plasma gun could optimally work before its destruction. Objectives: The aim of the research is to determine the optimal operating time of the plasma gun between renovations (the renovation shall involve the replacement of the test components of the plasma gun: electrode, nozzle plate, powder injector. Methodology: Plasma jet and particle flux analysis with PFI (PFI is a diagnostic tool for all kinds of thermal spraying processes), CT reconstruction and analysis on the new and the used plasma guns, failure analysis of electrodes, nozzle plates, and powder injectors, microscopic examination of the microstructure of the coating. Contributions: As the result of the failure analysis detailed above, the use of the plasma gun was maximized at 100 operating hours in order to get optimal microstructure for the coat.

Keywords: APS, air plasma spray, failure analysis, electrode, nozzle plate, powder injector

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Authors: Magdy G. Asaad

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Solitons are among the most beneficial solutions for science and technology for their applicability in physical applications including plasma, energy transport along protein molecules, wave transport along poly-acetylene molecules, ocean waves, constructing optical communication systems, transmission of information through optical fibers and Josephson junctions. In this talk, we will apply the bilinear technique to generate a class of soliton solutions to the (3+1)-dimensional nonlinear soliton equation of Jimbo-Miwa type. Examples of the resulting soliton solutions are computed and a few solutions are plotted.

Keywords: Pfaffian solutions, N-soliton solutions, soliton equations, Jimbo-Miwa

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Authors: G. R. Kavitha, T. S. Indumathi

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With the constantly rising demands of the multimedia services, the requirements of long haul transport network are constantly changing in the area of optical network. Maximum data transmission using optimization of the communication channel poses the biggest challenge. Although there has been a constant focus on this area from the past decade, there was no evidence of a significant result that has been accomplished. Hence, after reviewing some potential design of optical network from literatures, it was understood that optical signal to noise ratio was one of the elementary attributes that can define the performance of the optical network. In this paper, we propose a framework termed as ECON (Enhanced Constraint-based Optical Network) that primarily optimize the optical signal to noise ratio using ROADM. The simulation is performed in Matlab and optical signal to noise ratio is extracted considering the system matrix. The outcome of the proposed study shows that optimized OSNR as compared to the existing studies.

Keywords: component, optical network, reconfigurable optical add-drop multiplexer, optical signal-to-noise ratio

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Authors: Ahmed El-Fiqi, Hae-Won Kim

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Incorporation of therapeutic elements such as Sr, Cu and Co into bioglass structure and their release as ions is considered as one of the promising approaches to enhance cellular responses, e.g., osteogenesis and angiogenesis. Here, cobalt as angiogenesis promoter has been incorporated (at 0, 1 and 4 mol%) into sol-gel derived calcium silicate mesoporous bioglass nanoparticles. The composition and structure of cobalt-free (CFN) and cobalt-doped (CDN) mesoporous bioglass nanoparticles have been analyzed by X-ray fluorescence (XRF), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier-Transform Infra-red spectroscopy (FT-IR). The physicochemical properties of CFN and CDN have been investigated using high-resolution transmission electron microscopy (HR-TEM), Selected area electron diffraction (SAED), and Energy-dispersive X-ray (EDX). Furthermore, the textural properties, including specific surface area, pore-volume, and pore size, have been analyzed from N²⁻sorption analyses. Surface charges of CFN and CDN were also determined from surface zeta potential measurements. The release of ions, including Co²⁺, Ca²⁺, and SiO₄⁴⁻ has been analyzed using inductively coupled plasma atomic emission spectrometry (ICP-AES). Loading and release of diclofenac as an anti-inflammatory drug model were explored in vitro using Ultraviolet-visible spectroscopy (UV-Vis). XRD results ensured the amorphous state of CFN and CDN whereas, XRF further confirmed that their chemical compositions are very close to the designed compositions. HR-TEM analyses unveiled nanoparticles with spherical morphologies, highly mesoporous textures, and sizes in the range of 90 - 100 nm. Moreover, N²⁻ sorption analyses revealed that the nanoparticles have pores with sizes of 3.2 - 2.6 nm, pore volumes of 0.41 - 0.35 cc/g and highly surface areas in the range of 716 - 830 m²/g. High-resolution XPS analysis of Co 2p core level provided structural information about Co atomic environment and it confirmed the electronic state of Co in the glass matrix. ICP-AES analysis showed the release of therapeutic doses of Co²⁺ ions from 4% CDN up to 100 ppm within 14 days. Finally, diclofenac loading and release have ensured the drug/ion co-delivery capability of 4% CDN.

Keywords: mesoporous bioactive glass, nanoparticles, cobalt ions, release

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Authors: X. L. Zhou, S. Tunmee, I. Toda, K. Komatsu, S. Ohshio, H. Saitoh

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Hydrogenated amorphous carbon (a-C:H) films have been synthesized by a radio frequency plasma enhanced chemical vapor deposition (rf-PECVD) technique with different bias voltage from 0.0 to -0.5 kV. The Raman spectra displayed the polymer-like hydrogenated amorphous carbon (PLCH) film with 0.0 to -0.1 and a-C:H films with -0.2 to -0.5 kV of bias voltages. The surface chemical information of all films were studied by X-ray photo electron spectroscopy (XPS) technique, presented to C-C (sp2 and sp3) and C-O bonds, and relative carbon (C) and oxygen (O) atomics contents. The O contamination had affected on structure and optical properties. The true density of PLCH and a-C:H films were characterized by X-ray refractivity (XRR) method, showed the result as in the range of 1.16-1.73 g/cm3 that depending on an increasing of bias voltage. The hardness was proportional to the true density of films. In addition, the optical properties i.e. refractive index (n) and extinction coefficient (k) of these films were determined by a spectroscopic ellipsometry (SE) method that give formation to in 1.62-2.10 (n) and 0.04-0.15 (k) respectively. These results indicated that the optical properties confirmed the Raman results as presenting the structure changed with applied bias voltage increased.

Keywords: negative bias voltage, a-C:H film, oxygen contamination, optical properties

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Authors: Saleh H. Abud, Z. Hassan, F. K. Yam

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Characteristics of MSM photodetector based on a porous In0.08Ga0.92N thin film were reported. Nanoporous structures of n-type In0.08Ga0.92N/AlN/Si thin films were synthesized by photoelectrochemical (PEC) etching at a ratio of 1:4 of HF:C2H5OH solution for 15 min. The structural and optical properties of pre- and post-etched thin films were investigated. Field emission scanning electron microscope and atomic force microscope images showed that the pre-etched thin film has a sufficiently smooth surface over a large region and the roughness increased for porous film. Blue shift has been observed in photoluminescence emission peak at 300 K for porous sample. The photoluminescence intensity of the porous film indicated that the optical properties have been enhanced. A high work function metals (Pt and Ni) were deposited as a metal contact on the porous films. The rise and recovery times of the devices were investigated at 390 nm chopped light. Finally, the sensitivity and quantum efficiency were also studied.

Keywords: porous InGaN, photoluminescence, SMS photodetector, atomic force microscopy

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Authors: Meihua Fang, Yipan Guo, Tao Fei, Pengyu Tian

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Space plasma caused spacecraft surface charging is the major space environment hazard. Particle in cell (PIC) method can be used to simulate the interaction between space plasma and spacecraft. It was proved that surface charging level of spacecraft in Jupiter’s orbits was high for its’ electron-heavy plasma environment. In this paper, Jovian plasma environment is modeled and surface charging analysis is carried out by PIC based software Spacecraft Plasma Interaction System (SPIS). The results show that the spacecraft charging potentials exceed 1000V at 2Rj, 15Rj and 25Rj polar orbits in the dark side at worst case plasma model. Furthermore, the simulation results indicate that the large Jovian magnetic field increases the surface charging level for secondary electron gyration.

Keywords: Jupiter, PIC, space plasma, surface charging

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Authors: Jihoon Park, Sungkon Yu, Byungjo Jung

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Although various optical tissue phantoms (OTPs) simulating human skin have been actively studied, their completeness is unclear because skin tissue has the intricate optical property and complicated structure disturbing the optical simulation. In this study, we designed multilayer OTP mimicking skin structure, and fabricated OTP models simulating skin-blood vessel and skin pigmentation in the skin, which are useful in Biomedical optics filed. The OTPs were characterized with the optical property and the cross-sectional structure, and analyzed by using various optical tools such as a laser speckle imaging system, OCT and a digital microscope to show the practicality. The measured optical property was within 5% error, and the thickness of each layer was uniform within 10% error in micrometer scale.

Keywords: blood vessel, optical tissue phantom, optical property, skin tissue, pigmentation

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Authors: Mehtap Çalışkan, Nilüfer Yıldız Varan, Volkan Kaplan

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New orientations have emerged in the textile sector as a result of increasing global competition and environmental problems. Under the scope of new understandings, it is required to bring forward multi-functional, simple and environmentally friendly methods that will meet tight economic and ecological demands of today. Plasma technology has become a significant alternative in this sense. This technology may provide great advantages in case it is developed, however, it does not receive adequate consideration. In this study, plasma treatment was applied by using glow discharge plasma system to 100% polyethylene terephthalate (PET) and 95% PET/5% elastane fabrics and then the effects of plasma polymerization on fabric surface was tested and analyzed using water and oil repellent finishes.

Keywords: plasma, polyester, elastane, water repellency, oil repellency

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Authors: Faten Adel Ismael Chaqmaqchee

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Optical, electrical and optical-electrical characterisations of surface light emitting VCSOAs devices are reported. The hot electron light emitting and lasing in semiconductor hetero-structure vertical cavity semiconductor optical amplifier (HELLISH VCSOA) device is a surface emitter based on longitudinal injection of electron and hole pairs in their respective channels. Ga0.35In0.65N0.02As0.08/GaAs was used as an active material for operation in the 1.3 μm window of the optical communications. The device has undoped Distributed Bragg Reflectors (DBRs) and the current is injected longitudinally, directly into the active layers and does not involve DBRs. Therefore, problems associated with refractive index contrast and current injection through the DBR layers, which are common with the doped DBRs in conventional VCSOAs, are avoided. The highest gain of around 4 dB is obtained for the 1300 nm wavelength operation.

Keywords: HELLISH, VCSOA, GaInNAs, luminescence, gain

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Authors: Patrizia Firmani, Sara Perucchini, Irene Rapone, Raffella Borrelli, Stefano Chiaberge, Manuela Grande, Rosamaria Marrazzo, Alberto Savoini, Andrea Siviero, Silvia Spera, Fabio Vago, Davide Deriu, Sergio Fanutti, Alessandro Oldani

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According to the Renewable Energy Directive II, the use of palm oil in diesel will be gradually reduced from 2023 and should reach zero in 2030 due to the deforestation caused by its production. Eni aims at finding alternative feedstocks for its biorefineries to eliminate the use of palm oil by 2023. Therefore, the ideal vegetable oils to be used in bio-refineries are those obtainable from plants that grow in marginal lands and with low impact on food-and-feed chain; hence, Eni research is studying the possibility of using oleaginous seeds, such as castor, croton, and cotton, to extract the oils to be exploited as feedstock in bio-refineries. To verify their suitability for the upgrading processes, an analytical protocol for their characterization has been drawn up and applied. The analytical characterizations include a step of water and ashes content determination, elemental analysis (CHNS analysis, X-Ray Fluorescence, Inductively Coupled Plasma - Optical Emission Spectroscopy, ICP– Mass Spectrometry), and total acid number determination. Gas chromatography coupled to flame ionization detector (GC-FID) is used to quantify the lipid content in terms of free fatty acids, mono-, di- and triacylglycerols, and fatty acids composition. Eventually, Nuclear Magnetic Resonance and Fourier Transform-Infrared spectroscopies are exploited with GC-MS and Fourier Transform-Ion Cyclotron Resonance to study the composition of the oils. This work focuses on the GC-FID analysis of the lipid fraction of these oils, as the main constituent and of greatest interest for bio-refinery processes. Specifically, the lipid component of the extracted oil was quantified after sample silanization and transmethylation: silanization allows the elution of high-boiling compounds and is useful for determining the quantity of free acids and glycerides in oils, while transmethylation leads to a mixture of fatty acid esters and glycerol, thus allowing to evaluate the composition of glycerides in terms of Fatty Acids Methyl Esters (FAME). Cotton oil was extracted from cotton oilcake, croton oil was obtained by seeds pressing and seeds and oilcake ASE extraction, while castor oil comes from seed pressing (not performed in Eni laboratories). GC-FID analyses reported that the cotton oil is 90% constituted of triglycerides and about 6% diglycerides, while free fatty acids are about 2%. In terms of FAME, C18 acids make up 70% of the total and linoleic acid is the major constituent. Palmitic acid is present at 17.5%, while the other acids are in low concentration (<1%). Both analyzes show the presence of non-gas chromatographable compounds. Croton oils from seed pressing and extraction mainly contain triglycerides (98%). Concerning FAME, the main component is linoleic acid (approx. 80%). Oilcake croton oil shows higher abundance of diglycerides (6% vs ca 2%) and a lower content of triglycerides (38% vs 98%) compared to the previous oils. Eventually, castor oil is mostly constituted of triacylglycerols (about 69%), followed by diglycerides (about 10%). About 85.2% of total FAME is ricinoleic acid, as a constituent of triricinolein, the most abundant triglyceride of castor oil. Based on the analytical results, these oils represent feedstocks of interest for possible exploitation as advanced biofuels.

Keywords: analytical protocol, biofuels, biorefinery, gas chromatography, vegetable oil

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Authors: Rama Bhattacharyya, S. N. Ojha, Umesh K. Singh

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Anthropogenic control on groundwater chemistry has emerged as a critical concern now-a-days, especially in the industrial areas. In view of this, a comprehensive study on the distribution of the heavy metal in the groundwater was conducted to investigate the impact of urbanization in the aquatic media. Water samples either from well or borehole from Fourty different sites in and around, Durgapur, West Bengal were collected for this purpose. The samples were analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for Calcium (Ca), Cobalt (Co), Chromium (Cr), Copper (Cu), Iron (Fe), Potassium (K), Magnesium (Mg), Manganese (Mn), Sodium (Na), Nickel (Ni), Lead (Pb), Zinc (Zn) content and the levels were compared with WHO specified maximum contaminant level as well as permissible limits given by the Bureau of Indian Standards (BIS). The result obtained from the present study indicates a significant risk to the population of this important emerging ‘smart city’ of eastern India. Because of the toxicity of these metals and the fact that for many tube-wells, dug-wells and bore-wells are the only sources of the water supply for a major fraction of the population in this environment. In this study, an attempt has been made to develop metal contamination risk map.

Keywords: heavy metals, ground water, maximum contamination level, ICP-MS

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Authors: Djemai Bara, Mohamed Faouzi Mahboub, Djamila Bennaceur-Doumaz

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In this work, the role of the preformed plasma created on the front face of a target, irradiated by a high intensity short pulse laser, in the framework of ion acceleration process, modeled by Target Normal Sheath Acceleration (TNSA) mechanism, is studied. This plasma is composed of cold ions governed by fluid equations and non-thermal & trapped with densities represented by a "Cairns-Gurevich" equation. The self-similar solution of the equations shows that electronic trapping and the presence of non-thermal electrons in the pre-plasma are both responsible in ion acceleration as long as the proportion of energetic electrons is not too high. In the case where the majority of electrons are energetic, the electrons are accelerated directly by the ponderomotive force of the laser without the intermediate of an accelerating plasma wave.

Keywords: Cairns-Gurevich Equation, ion acceleration, plasma expansion, pre-plasma

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Authors: A. N. Dagang, E. I. Ismail, Z. Zakaria

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This paper presents the analysis on the performance of monopole antenna with fluorescent tubes. In this research, the simulation and experimental approach is conducted. The fluorescent tube with different length and size is designed using Computer Simulation Technology (CST) software and the characteristics of antenna parameter are simulated throughout the software. CST was used to simulate antenna parameters such as return loss, resonant frequency, gain and directivity. Vector Network Analyzer (VNA) was used to measure the return loss of plasma antenna in order to validate the simulation results. In the simulation and experiment, the supply frequency is set starting from 1 GHz to 10 GHz. The results show that the return loss of plasma antenna changes when size of fluorescent tubes is varied, correspond to the different plasma properties. It shows that different values of plasma properties such as plasma frequency and collision frequency gives difference result of return loss, gain and directivity. For the gain, the values range from 2.14 dB to 2.36 dB. The return loss of plasma antenna offers higher value range from -22.187 dB to -32.903 dB. The higher the values of plasma frequency and collision frequency, the higher return loss can be obtained. The values obtained are comparative to the conventional type of metal antenna.

Keywords: plasma antenna, fluorescent tube, CST, plasma parameters

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Authors: Leila Graini

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In this paper, we demonstrate basic all-optical functions for 2R regeneration (Re-amplification and Re-shaping) based on self-similar spectral broadening in low normal dispersion and highly nonlinear fiber (ND-HNLF) to regenerate the signal through optical filtering including the transfer function characteristics, and output extinction ratio. Our approach of all-optical 2R regeneration is based on those of Mamyshev. The numerical study reveals the self-similar spectral broadening very effective for 2R all-optical regeneration; the proposed design presents high stability compared to a conventional regenerator using SPM broadening with reduction of the intensity fluctuations and improvement of the extinction ratio.

Keywords: all-optical function, 2R optical regeneration, self-similar broadening, Mamyshev regenerator

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Authors: Mehtap Çalışkan, Nilüfer Yıldız Varan, Volkan Kaplan

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In this study, the effects of an atmospheric plasma treatment on the durability of water and oil repellent finishes of PET and PET/Spandex fabrics were tested. Fabrics were treated with a low-frequency atmospheric pressure glow discharge. After plasma treatments, the water and oil repellent finishes were applied using pad-dry-cure method. It was observed that plasma treatments improved the durability finish for all fabrics.

Keywords: atmospheric plasma, durable coating, oil repellency, PET/spandex fabrics, water repellency

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Authors: Muhammad Asif ShakoorI, Maogang He, Aamir Shahzad

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Dusty (complex) plasmas contained micro-sized charged dust particles in addition to ions, electrons, and neutrals. It is typically low-temperature plasma and exists in a wide variety of physical systems. In this work, the effects of an external electric field on the diffusion coefficient and share viscosity are investigated through equilibrium molecular dynamics (EMD) simulations in three-dimensional (3D) strongly coupled (SC) dusty plasmas (DPs). The effects of constant and varying normalized electric field strength (E*) have been computed along with different combinations of plasma states on the diffusion of dust particles using EMD simulations. Diffusion coefficient (D) and share viscosity (η) along with varied system sizes, in the limit of varying E* values, is accounted for an appropriate range of plasma coupling (Γ) and screening strength (κ) parameters. At varying E* values, it is revealed that the 3D diffusion coefficient increases with increasing E* and κ; however, it decreases with an increase of Γ but within statistical limits. The share viscosity increases with increasing E*and Γ and decreases with increasing κ. New simulation results are outstanding that the combined effects of electric field and screening strengths give well-matched values of Dandη at low-intermediate to large Γ with varying small-intermediate to large N. The current EMD simulation outcomes under varying electric field strengths are in satisfactory well-matched with previous known simulation data of EMD simulations of the SC-DPs. It has been shown that the present EMD simulation data enlarged the range of E* strength up to 0.1 ≤ E*≤ 1.0 in order to find the linear range of the DPs system and to demonstrate the fundamental nature of electric field linearity of 3D SC-DPs.

Keywords: strongly coupled dusty plasma, diffusion coefficient, share viscosity, molecular dynamics simulation, electric field strength

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Authors: Sharda Nara, Bansi Dhar Malhotra

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Investigation of the vitamins as an electron transfer mediator could significantly assist in merging the area of tissue engineering and electronics required for the implantable therapeutic devices. The present study report that the molecules of folic acid released by Providencia rettgeri via fermentation route under the anoxic condition of the microbial fuel cell (MFC) exhibit characteristic electrochemical and optical properties, as indicated by absorption spectroscopy, photoluminescence (PL), and cyclic voltammetry studies. The absorption spectroscopy has depicted an absorption peak at 263 nm with a small bulge around 293 nm on day two of bacterial culture, whereas an additional peak was observed at 365 nm on the twentieth day. Furthermore, the PL spectra has indicated that the maximum emission occurred at various wavelengths 420, 425, 440, and 445 nm when excited by 310, 325, 350, and 365 nm. The change of emission spectra with varying excitation wavelength might be indicating the presence of tunable optical bands in the folic acid molecules co-related with the redox activity of the molecules. The results of cyclic voltammetry studies revealed that the oxidation and reduction occurred at 0.25V and 0.12V, respectively, indicating the electrochemical behavior of the folic acid. This could be inferred that the released folic acid molecules in a MFC might undergo inter as well as intra molecular electron transfer forming different intermediate states while transferring electrons to the electrode surface. Synchronization of electrochemical and optical properties of folic acid molecules could be potentially promising for the designing of electroactive scaffold and biocompatible conductive surface for the applications of tissue engineering and biofuel cells, respectively.

Keywords: biofuel cell, electroactivity, folic acid, tissue engineering

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Authors: Valentina Alessandra Carvalho do Vale, Elmo Thiago Lins Cöuras Ford

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Increasingly telecommunications sectors are adopting optical technologies, due to its ability to transmit large amounts of data over long distances. However, as in all systems of data transmission, optical communication channels suffer from undesirable and non-deterministic effects, being essential to know the same. Thus, this research allows the assessment of these effects, as well as their characterization and beneficial uses of these effects.

Keywords: optical communication, optical fiber, non-deterministic effects, telecommunication

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Authors: Melissa R. Quispe-Zuniga, Daniel Callo-Concha, Christian Borgemeister, Klaus Greve

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The Peruvian Andes have a high potential for mining, but many of the mining areas overlay with campesino community lands, being these key actors for agriculture and livestock production. Lead by economic incentives, some communities are renting their lands to mining companies for exploration or exploitation. However, a growing number of campesino communities, usually social and economically marginalized, have developed resistance, alluding consequences, such as water pollution, land-use change, insufficient economic compensation, etc. what eventually end up in Socio-Environmental Conflicts (SEC). It is hypothesized that disclosing the information on environmental pollution and enhance the involvement of communities in the decision-making process may contribute to prevent SEC. To assess whether such complains are grounded on the environmental impact of mining activities, we measured the heavy metals concentration in 24 indicative samples from rivers that run across mining exploitations and farming community lands. Samples were taken during the 2016 dry season and analyzed by inductively-coupled-plasma-atomic-emission-spectroscopy. The results were contrasted against the standards of monitoring government institutions (i.e., OEFA). Furthermore, we investigated the water/environmental complains related to mining in the neighboring 14 communities. We explored the relationship between communities and mining companies, via open-ended interviews with community authorities and non-participatory observations of community assemblies. We found that the concentrations of cadmium (0.023 mg/L), arsenic (0.562 mg/L) and copper (0.07 mg/L), surpass the national water quality standards for Andean rivers (0.00025 mg/L of cadmium, 0.15 mg/L of arsenic and 0.01 mg/L of copper). 57% of communities have posed environmental complains, but 21% of the total number of communities were receiving an annual economic benefit from mining projects. However, 87.5% of the communities who had posed complains have high concentration of heavy metals in their water streams. The evidence shows that mining activities tend to relate to the affectation and vulnerability of campesino community water streams, what justify the environmental complains and eventually the occurrence of a SEC.

Keywords: mining companies, campesino community, water, socio-environmental conflict

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Authors: Sheila Shahidi, Hootan Rezaee, Abosaeed Rashidi, Mahmood Ghoranneviss

Abstract:

Plasma treatment has an explosive increase in interest and use in industrial applications as for example in medical, biomedical, automobile, electronics, semiconductor and textile industry. A lot of intensive basic research has been performed in the last decade in the field of textiles along with technical textiles. Textile manufacturers and end-users alike have been searching for ways to improve the surface properties of natural and man-made fibers. Specifically, there is a need to improve adhesion and wettability. Functional groups may be introduced onto the fiber surface by using gas plasma treatments, improving fiber surface properties without affecting the fiber’s bulk properties. In this research work, ZnO nanoparticles (ZnO-NPs) were insitue synthesized by sonochemical method at room temperature on both untreated and plasma pretreated cotton woven fabric. Oxygen and nitrogen plasmas were used for pre-functionalization of cotton fabric. And the effect of oxygen and nitrogen pre-functionalization on adhesion properties between ZnO nanoparticles and cotton surface were studied. The results show that nanoparticles with average sizes of 20-100 nm with different morphologies have been created on the surface of samples. Synthesis of ZnO-NPs was varied in the morphological transformation by changes in zinc acetate dehydrate concentration. Characterizations were carried out using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Inductive coupled plasma (ICP) and Spectrophotometery. The antibacterial activities of the fabrics were assessed semi-quantitatively by the colonies count method. The results show that the finished fabric demonstrated significant antibacterial activity against S. aureus in antibacterial test. The wash fastness of both untreated and plasma pretreated samples after 30 times of washing was investigated. The results showed that the parameters of plasma reactor plays very important role for improving the antibacterial durability.

Keywords: antibacterial activity, cotton, fabric, nanoparticles, plasma

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Authors: Renu Kumari, Jyotsna Dutta Majumdar

Abstract:

In the present study, composite coating consisting of hydroxyapatite (HA) + 50 wt% TiO2 has been developed on Ti-6Al-4V substrate by plasma spray deposition technique. Followed by plasma spray deposition, detailed surface roughness and microstructural characterization were carried out by using optical profilometer and scanning electron microscopy (SEM), respectively. The composition and phase analysis were carried out by energy-dispersive X-ray spectroscopy analysis, and X-ray diffraction (XRD) technique, respectively. The bio-activity behavior of the uncoated and coated samples was also compared by dipping test in Hank’s solution. The average surface roughness of the coating was 10 µm (as compared to 0.5 µm of as-received Ti-6Al-4V substrate) with the presence of porosities. The microstructure of the coating was found to be continuous with the presence of solidified splats. A detailed XRD analysis shows phase transformation of TiO2 from anatase to rutile, decomposition of hydroxyapatite, and formation of CaTiO3 phase. Standard dipping test confirmed a faster kinetics of deposition of calcium phosphate in the coated HA+50% wt.% TiO2 surface as compared to the as-received substrate.

Keywords: titanium, plasma spraying, microstructure, bio-activity, TiO2, hydroxyapatite

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Authors: Junze Li, M. Li

Abstract:

Laser diodes fabricated from the III-nitride material system are emerging solutions for the next generation telecommunication systems and optical clocks based on Ca at 397nm, Rb at 420.2nm and Yb at 398.9nm combined 556 nm. Most of the applications require single longitudinal optical mode lasers, with very narrow linewidth and compact size, such as communication systems and laser cooling. In this case, the GaN based distributed feedback (DFB) laser diode is one of the most effective candidates with gratings are known to operate with narrow spectra as well as high power and efficiency. Given the wavelength range, the period of the first-order diffraction grating is under 100 nm, and the realization of such gratings is technically difficult due to the narrow line width and the high quality nitride overgrowth based on the Bragg grating. Some groups have reported GaN DFB lasers with high order distributed feedback surface gratings, which avoids the overgrowth. However, generally the strength of coupling is lower than that with Bragg grating embedded into the waveguide within the GaN laser structure by two-step-epitaxy. Therefore, the overgrowth on the grating technology need to be studied and optimized. Here we propose to fabricate the fine step shape structure of first-order grating by the nanoimprint combined inductively coupled plasma (ICP) dry etching, then carry out overgrowth high quality AlGaN film by metalorganic chemical vapor deposition (MOCVD). Then a series of gratings with different period, depths and duty ratios are designed and fabricated to study the influence of grating structure to the nano-heteroepitaxy. Moreover, we observe the nucleation and growth process by step-by-step growth to study the growth mode for nitride overgrowth on grating, under the condition that the grating period is larger than the mental migration length on the surface. The AFM images demonstrate that a smooth surface of AlGaN film is achieved with an average roughness of 0.20 nm over 3 × 3 μm2. The full width at half maximums (FWHMs) of the (002) reflections in the XRD rocking curves are 278 arcsec for the AlGaN film, and the component of the Al within the film is 8% according to the XRD mapping measurement, which is in accordance with design values. By observing the samples with growth time changing from 200s, 400s to 600s, the growth model is summarized as the follow steps: initially, the nucleation is evenly distributed on the grating structure, as the migration length of Al atoms is low; then, AlGaN growth alone with the grating top surface; finally, the AlGaN film formed by lateral growth. This work contributed to carrying out GaN DFB laser by fabricating grating and overgrowth on the nano-grating patterned substrate by wafer scale, moreover, growth dynamics had been analyzed as well.

Keywords: DFB laser, MOCVD, nanoepitaxy, III-niitride

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