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Fractal and spectroscopic analysis of soot from internal combustion engines
Sankararaman S, RAJ VIMAL, SARITHA DEVI H V, Swapna Mohanachandran Nair Sindhu, 2018, original scientific article

Abstract: Today diesel engines are used worldwide for various applications and very importantly in transportation. Hydrocarbons are the most widespread precursors among carbon sources employed in the production of carbon nanotubes (CNTs). The aging of internal combustion engine is an important parameter in deciding the carbon emission and particulate matter due to incomplete combustion of fuel. In the present work, an attempt has been made for the effective utilization of the aged engines for potential applicationapplications in fuel cells and nanoelectronics. To analyze the impact of aging, the particulate matter rich in carbon content areis collected from diesel engines of different ages. The soot with CNTs is purified by the liquid phase oxidation method and analyzed by Field Emission Scanning Electron Microscopy, High-Resolution Transmission Electron Microscopy, Energy Dispersive Spectroscopy, UV-Visible spectroscopy, Raman spectroscopy and Thermogravimetric analysis. The SEM image contains self-similar patterns probing fractal analysis. The fractal dimensions of the samples are determined by the box counting method. We could find a greater amount of single-walled carbon nanotubes (SWCNTs) in the particulate matter emitted by aged diesel engines and thereby giving information about the combustion efficiency of the engine. The SWCNT rich sample finds a wide range of applications in nanoelectronics and thereby pointing a potential use of these aged engines.
Found in: osebi
Keywords: Fractals, internal combustion engine, efficiency, soot, carbon nanoparticle
Published: 30.06.2022; Views: 408; Downloads: 0
.pdf Fulltext (1,05 MB)

From futile to fruitful: Diesel soot as white light emitter
Swapna Mohanachandran Nair Sindhu, Sankararaman S, 2018, original scientific article

Abstract: The present work describes a solution for the effective use of the hazardous particulate matter (diesel soot) from the internal combustion engines (ICEs) as a potential material emitting white light for white light emitting diodes (WLEDs). The washed soot samples are subjected to Field Emission Scanning Electron Microscopy (FESEM), High- Resolution Transmission Electron Microscopy (HR-TEM), Energy Dispersive Spectroscopy (EDS), UV-Visible, Photoluminescent (PL) Spectroscopy and quantum yield measurements. The CIE plot and Correlated Color Temperature (CCT) reveals the white fluorescence on photoexcitation. The sample on ultraviolet (UV) laser excitation, provides a visual confirmation of white light emission from the sample. The diesel soot collected from public transport buses of different years of manufacture invariably exhibit white fluorescence at an excitation of 350 nm. The sample show a quantum yield of 47.09%. The study is significant in the context of pollution and search for low-cost, rare-earth phosphor free material for white light emission and thereby turning the hazardous, futile material into a fruitful material that can be used for potential applications in photonics and electronics.
Found in: osebi
Keywords: White light emitter, Diesel soot, CIE plot, Quantum yield, Fluorescence
Published: 30.06.2022; Views: 388; Downloads: 0
.pdf Fulltext (1,82 MB)

Blue light emitting diesel soot for photonic applications
Sankararaman S, Swapna Mohanachandran Nair Sindhu, 2018, original scientific article

Abstract: The present work is the first report of producing blue light emission from phosphor free and low-cost material—the diesel soot from the internal combustion engines (ICEs). The structural morphology is analyzed by field emission scanning electron microscopy and high-resolution transmission electron microscopy. The optical characterization is done by recording UV–visible spectrum and photoluminescent Spectrum. The CIE plot and the power spectrum for the sample show blue emission. This is further verified by collecting diesel soot from the ICE of different year of make. A visual confirmation of blue emission is obtained by exciting the sample with UV laser. The presence of various allotropic forms of carbon in the sample is identified by x-ray diffraction, Fourier transform infrared and Raman spectroscopic analysis.
Found in: osebi
Keywords: blue light emitter, diesel soot, photoluminescence, CIE plot
Published: 30.06.2022; Views: 407; Downloads: 0
.pdf Fulltext (1,96 MB)

Natural precursor based hydrothermal synthesis of sodium carbide for reactor applications
Swapna Mohanachandran Nair Sindhu, 2017, original scientific article

Abstract: Carbides are a class of materials with high mechanical strength and refractory nature which finds a wide range of applications in industries and nuclear reactors. The existing synthesis methods of all types of carbides have problems in terms of use of toxic chemical precursors, high-cost, etc. Sodium carbide (Na2C2) which is an alkali metal carbide is the least explored one and also that there is no report of low-cost and low-temperature synthesis of sodium carbide using the eco-friendly, easily available natural precursors. In the present work, we report a simple low-cost, non-toxic hydrothermal synthesis of refractory sodium carbide using the natural precursor—Pandanus. The formation of sodium carbide along with boron carbide is evidenced by the structural and morphological characterizations. The sample thus synthesized is subjected to field emission scanning electron microscopy (FESEM), x-ray powder diffraction (XRD), ultraviolet (UV)—visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), Raman, and photoluminescent (PL) spectroscopic techniques.
Found in: osebi
Keywords: sodium carbide, pandanus, hydrothermal synthesis, porous materials
Published: 30.06.2022; Views: 415; Downloads: 0
.pdf Fulltext (2,57 MB)

Fractal analysis - a surrogate technique for material characterization
Sankararaman S, Swapna Mohanachandran Nair Sindhu, 2017, original scientific article

Abstract: Fractal analysis has emerged as a potential analytical tool in almost all branches of science and technology. The paper is the first report of using fractal dimension as a surrogate technique for estimating particle size. A regression equation is set connecting the soot particle size and fractal dimension, after investigating the Field Emission Scanning Electron Microscopic (FESEM) images of carbonaceous soot from five different sources. Since the fractal dimension is an invariant property under the scale transformation, an ordinary photograph of the soot should also yield the same fractal dimension. This enables one to determine the average size of the soot particles, using the regression equation, by calculating the fractal dimension from the photograph. Hence, instead of frequent measurement of average particle size from FESEM, this technique of estimating the particle size from the fractal dimension of the soot photograph, is found to be a potentially cost-effective and non-contact method.
Found in: osebi
Keywords: fractals, FESEM, carbon nanoparticles, particle size, box-counting
Published: 30.06.2022; Views: 391; Downloads: 0
.pdf Fulltext (3,05 MB)

Camphor soot: A Tunable Light Emitter
Sankararaman S, SARITHA DEVI H V, Swapna Mohanachandran Nair Sindhu, 2018, original scientific article

Abstract: The work in this paper is the first report on the green synthesis of the blue light emitter from waxy, flammable solid collected from Cinnamomum camphora by controlled combustion for photonic applications. Analysis with field emission scanning electron microscope and high-resolution transmission electron microscope provides the morphology, whereas the thermo-gravimetric analysis gives the thermal stability of the soot. The optical and structural characterizations are done by recording UV–Visible, Photoluminescent, and Raman Spectrum. The CIE plot and the power spectrum of the sample show a blue emission at an excitation of 350 nm at room temperature with a quantum yield of 46.15%. The dependence of luminescent behavior on temperature and excitation wavelength reveals that the material is a tunable blue emitter. This green synthesis of the blue light emitter is highly significant, when the world is in search of a simple, phosphor-free, non-toxic, cost-effective material with good quantum efficiency
Found in: osebi
Keywords: camphor, soot, blue light emitter
Published: 30.06.2022; Views: 314; Downloads: 0
.pdf Fulltext (2,16 MB)

Particulate Exhaust Analysis from Internal Combustion Engines
Swapna Mohanachandran Nair Sindhu, 2017, short scientific article

Abstract: Today the world is worried over the particulate emission from various forms of internal combustion engines. The present work is an attempt to understand the constituents of the particulate emission and its possible use. The particulate exhaust matter containing carbonaceous soot produced from the combustion of fuel containing hydrocarbons shows the presence of significant amount of carbon Nanomaterials. Hydrocarbons are the most widespread precursors among carbon sources employed in the production of carbon nanotubes (CNTs) and carbon nanoparticles (CNPs). Carbon nanotubes find application in fuel cells providing improved performance. The soot particles collected from the internal combustion diesel engines are cleaned, powdered and analyzed by various techniques. The CNPs are characterized by Field Emission Scanning Electron Microscopy (FESEM), X-Ray Powder Diffraction (XRD), Energy Dispersive X ray diffraction (EDS), Raman Spectroscopy, Photoluminescence spectroscopy (PL), Power spectrum and CIE plot. X Ray Diffraction and Raman spectroscopic analysis show the presence of carbon nanotubes in the amorphous materials.
Found in: osebi
Keywords: HydrocarbonsL Carbon nanotubes, Diesel engines, CIE plot, EDX, Raman spectroscopy
Published: 30.06.2022; Views: 399; Downloads: 0
.pdf Fulltext (672,31 KB)

Ultraviolet Protection Action of Carbon Nanoparticles in Leaves
Swapna Mohanachandran Nair Sindhu, 2017, original scientific article

Abstract: Carbon nanoparticles (CNPs) have been explored widely in many fields of science and technology owing to its unique physical, chemical, mechanical, and biological properties. The interaction of the visible region of the electromagnetic radiation with plants and their role in photosynthesis is well studied. The antenna pigments in the protein matrix of thylakoid play a significant role in energy transport mechanism involved in photosynthesis. The energy absorbed by the proteins in the UV region also involves in the energy transport. The present work is aimed to understand the absorption of radiation by leaves in the ultraviolet (UV) region and the impact of CNPs produced by internal combustion diesel engines (ICE) in altering the absorbance level. The effect of CNPs is found to lower the UVabsorbance by leaves and thus acting as UV shield, protecting the leaves from cell damages. The characterization of the CNP and leaves is done by field emission scanning electron microscope (FESEM) and UV-visible spectrophotometer.
Found in: osebi
Keywords: Ultraviolet, Carbon nanoparticles, Photosynthesis, Internal combustion engine
Published: 30.06.2022; Views: 368; Downloads: 0
.pdf Fulltext (1,41 MB)

Photoacoustics - A nondestructive evaluation technique for thermal and optical characterisation of metal mirrors
Sankararaman S, NAMPOORI V P N, Swapna Mohanachandran Nair Sindhu, 2018, original scientific article

Abstract: Photoacoustic technique has emerged as a powerful tool for nondestructive evaluation and characterization. The high signal to noise ratio, sensitivity, and the least quantity of sample required make the technique suitable for wide range of applications. The intensity modulated laser beam focused on to the sample in the photoacoustic cell generates acoustic waves. Analysis of the acoustic signal enables the measurement of thermal and optical properties of the material. In the present work, the photoacoustic technique has been extended to find the thermal diffusivity and to demonstrate how the technique can be used for measuring optical reflection coefficient of a precious metal mirror—Aranmula mirror. The mirror being metal with high reflection coefficient, it finds application in optical instrumentation. The mirror is subjected to morphological characterization by atomic force microscopy and field emission scanning electron microscopy. The elemental and structural characterizations are done by energy dispersive x-ray spectroscopy, X-ray dot mapping, and X-Ray diffraction analysis. The fractal dimension of the particle distribution over the surface provides information about the surface roughness. The box-counting and power spectral fractal dimensions are found to be around 1.63 and 1.65 respectively.
Found in: osebi
Keywords: Photoacoustics, Nondestructive evaluation, Aranmula metal mirror, Reflectivity
Published: 30.06.2022; Views: 421; Downloads: 0
.pdf Fulltext (1,48 MB)

Study of Drug Diffusion rate by beam deflection technique
Swapna Mohanachandran Nair Sindhu, 2017, original scientific article

Abstract: Drug administration is an unavoidable part of treatment. When a drug is administered orally or intravenously, it gets absorbed into the blood stream. The rate and efficiency of absorption depend on the route of administration. When a drug is administered through the oral route, it penetrates the epithelial cells of the intestinal mucosa. The diffusion of the drug into the blood stream depends on various parameters, such as concentration, temperature, and the nature of the mucous membrane. The passive diffusion of drugs is found to obey Fick’s law. Water soluble drugs penetrate the cell membrane through aqueous channel or pores. Hence, the study of diffusion of drugs into the water and finally into the blood stream is important. An attempt has been made to study the diffusion of the drug in water as 60% to 80% of human body is water. For the study of drug diffusion in water, a commonly used cough syrup of specific gravity 1.263 is used. It is found that the diffusion rate increases with the concentration of the drug.
Found in: osebi
Keywords: laser beam deflection, diffusion coefficient, Fick’s law, sodium chloride, syrup
Published: 30.06.2022; Views: 374; Downloads: 0
.pdf Fulltext (886,38 KB)

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