Search results for: nano topology

Authors: Seyed Mahdi Rafiaei

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In this investigation, red emitting Eu³⁺ doped YVO₄ nano-phosphors have been synthesized via the facile combustion method using isobutyl nitrite and urea fuels, individually. Field-emission scanning electron microscope (FE-SEM) images, high resolution transmission electron microscope (TEM) images and X-ray diffraction (XRD) spectra reveal that the mentioned fuels can be used successfully to synthesis YVO₄: Eu³⁺ nano-particles. Interestingly, the fuels have a large effect on the size and morphology of nano-phosphors as well as luminescence properties. Noteworthy the use of isobutyl nitrite provides an average particle size of 65 nm, while the employment of urea, results in the formation of larger particles and also provides higher photoluminescence emission intensity. The improved luminescence performance is attributed to the condition of chemical reaction via the combustion synthesis and the size of synthesized phosphors.

Keywords: phosphors, combustion, fuels, luminescence, nanostructure

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Authors: R. Hariprakash, K. Prabhakaran Nair

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In this paper, the static and dynamic characteristics of hydrodynamic journal bearings operating under nano lubricants are presented. Hydrodynamic journal bearings are used in turbo machines of power plants to support heavy load. In power plants, bearings are getting failure because of its inability to support the heavy load due to various reasons. Failures of bearings make the power plant to be shutdown. The load carrying capacity of journal bearing mainly depends upon the viscosity of the lubricants. The addition of nano particles on commercially available lubricant may enhance the viscosity of lubricant and in turn, change the performance characteristics. In the literature, though many studies have been carried out for the hydrodynamic bearing operating under Newtonian and non-Newtonian lubricants, studies on hydrodynamic bearings operating under nano lubricants is scarce. Thus, it is felt that there is a need to recompute the performance characteristics of journal bearings operating under nano lubricants.

Keywords: hydrodynamic, journal, bearing, analysis

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Authors: Osama Safwat Mohamed

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Pits and fissures dental caries can be prevented using sealant material. This study aimed to compare the microleakage and interfacial morphology of flowable nanocomposites and conventional pit and fissure sealants. 60 extracted intact and caries-free permanent mandibular third molars. The teeth were randomly divided into three groups (n = 20) according to the material used for pit and fissure sealant. Group I: Unfilled resin-based pits and fissure sealant, Group II: Unfilled resin-based pits and fissure sealant with bond and Group III: Nano flowable composite resin with bond. The results showed that nano-flowable composite was significantly better than the conventional sealants groups p = 0.000. As well there was better as well, there were gaps between sealants and the tooth surfaces in groups I and II, but for group III, there was close contact between the nano-flowable composite and tooth surfaces. It was concluded that nano-flowable composite showed better microleakage and interfacial morphology results than conventional pits and fissure sealant and offered promising results at the fissure sealing.

Keywords: pits and fissures, Sealant, nanocomposite, dental caries

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Authors: Mai M. Khalaf, Hany M. Abd El-Lateef

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A new good application for the sol gel method is to improve the corrosion inhibition properties of carbon steel by the dip coating method of Nano TiO2 films and its modification with Poly Ethylene Glycol (PEG). The prepared coating samples were investigated by different techniques, X-ray diffraction, Scanning Electron Microscopy (SEM), transmission electron microscopy and Energy Dispersive X-ray Spectroscopy (EDAX). The corrosion inhibition performance of the blank carbon steel and prepared coatings samples were evaluated in 0.5 M H2SO4 by using Electrochemical Impedance Spectroscopy (EIS) and potentiodynamic polarization measurements. The results showed that corrosion resistance of carbon steel increases with increasing the number of coated layers of both nano–TiO2 films and its modification of PEG. SEM-EDAX analyses confirmed that the percentage atomic content of iron for the carbon steel in 0.5 M H2SO4 is 83% and after the deposition of the steel in nano TiO2 sol and that with PEG are 94.3% and 93.7% respectively.

Keywords: dip-coatings, corrosion protection, sol gel, TiO2 films, PEG

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Authors: Ting-Ting Wen, H. C. Lin

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This paper reports a study for the light outcoupling efficiency of the PLED device. In use of a designed substrate combined with nano-line patterns in PLED device, the light outcoupling efficiency can be significantly enhanced. The designed substrate was made by UV imprinting technology, such as triangular microlens arrays on the front and periodic corrugated patterns on the back surface. The nano-line patterns in PLED device was fabricated by advanced microstamping and ink-jet printing techniques. For high angles of observation with respect to the substrate surface normal, the light out intensity of the developed PLED device is increased from 0.05 (a.u.) up to 0.69 (a.u.) at the view angle 85 degree. The designed integration leads to 64% increase of the light out intensity compared with the conventional PLED device.

Keywords: triangular microlens, corrugation patterns, nano-line patterns, PLED device, UV imprinting technology, microstamping

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Authors: M. Schapira, S. Françoise, F. Maheux, O. Pierre-Duplessix, E. Rabiller, B. Simon, R. Le Gendre

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Pico- and nano-phytoplankton are abundant and ecologically critical components of the autotrophic communities in the pelagic realm. While the role of physical forcing related to tidal cycle, water mass intrusion, nutrient availability, mixing and stratification on microphytoplankton blooms have been widely investigated, these are often overlooked for pico- and nano-phytoplankton especially in estuarine waters. This study investigates changes in abundances and community composition of pico- and nano-phytoplankton under different estuarine tidal conditions in the mouth of the Seine River in relation to nutrient availability, water column stratification and spatially localized currents. Samples were collected each day at high tide, over spring tide to neap tide cycle, from 21 stations homogeneously distributed in the Seine river month in May 2011. Vertical profiles of temperature, salinity and fluorescence were realized at each sampling station. Sub-surface water samples (i.e. 1 m depth) were collected for nutrients (i.e. N, P and Si), phytoplankton biomass (i.e. Chl a) and pico- and nano-phytoplankton enumeration and identification. Pico- and nano-phytoplankton populations were identified and quantified using flow cytometry. Total abundances tend to decrease from spring tide to neap tide. Samples were characterized by high abundances of Synechococcus and Cryptophyceae. The composition of the pico- and nano-phytoplankton varied greatly under the different estuarine tidal conditions. Moreover, at the scale of the river mouth, the pico- and nano-phytoplankton population exhibited patchy distribution patterns that were closely controlled by water mass intrusion from the Sea, freshwater inputs from the Seine River and the geomorphology of the river mouth. This study highlights the importance of physical forcing to the community composition of pico- and nano-phytoplankton that may be critical for the structure of the pelagic food webs in estuarine and adjacent coastal seas.

Keywords: nanophytoplancton, picophytoplankton, physical forcing, river mouth, tidal cycle

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Authors: Mehdi Ketabchi, Shamsollah Alijanlou

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The flue gas from fossil fuels combustion contains harmful pollutants dangerous for human health and the environment. One of the air pollution control methods to restrict the emission of these pollutants is based on using the nanoparticle in the adsorption process. In the present research gamma, Nano-alumina particle is added to Polyacrylonitrile (PAN) polymer through simple loading method and the adsorption capacity of the wet spun fiber is investigated. The results of exposure the fiber to the acid gasses including SO2, CO, NO2, NO and CO2 show the noticeable increase of gas adsorption capacity on fiber contains nanoparticle. The research has been conducted in Acrylic II Plant of Polyacryl Iran Corporation.

Keywords: acrylic fiber, adsorbent, wet spun, nano gamma alumina

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Authors: Dhivya Balakrishnan, Dhamodharan Shanmugam

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Multilevel converters offer high power capability, associated with lower output harmonics and lower commutation losses. Their main disadvantage is their complexity requiring a great number of power devices and passive components, and a rather complex control circuitry. This paper proposes a single-phase seven-level inverter for grid connected PV systems, With a novel pulse width-modulated (PWM) control scheme. Three reference signals that are identical to each other with an offset that is equivalent to the amplitude of the triangular carrier signal were used to generate the PWM signals. The inverter is capable of producing seven levels of output-voltage levels from the dc supply voltage. This paper proposes a new multilevel inverter topology using an H-bridge output stage with two bidirectional auxiliary switches. The new topology produces a significant reduction in the number of power devices and capacitors required to implement a multilevel output using the asymmetric cascade configuration.

Keywords: asymmetric cascade configuration, H-Bridge, multilevel inverter, Pulse Width Modulation (PWM)

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Authors: H. Shiu, M.S. Lu, Y.P. Tsai

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This study explored the impacts of CuO, TiO2, SiO2 nanoparticles on biological phosphorus removal. Experimental results showed that the phosphorus removal ability of phosphorus accumulating organism (PAO) was initially inhibited when CuO nanoparticle concentration was 5 mgl-1. The inhibition of phosphorus removal for 1000 mgl-1 of TiO2 with sunlight was higher than without sunlight case. The inhibition of phosphorus removal began at 500 mgl-1 SiO2 nanoparticle concentration. Inhibition became apparent when SiO2 nanoparticle concentration was up to 1000 mgl-1.

Keywords: nano copper oxide, nano titanium dioxide, nano silica, enhanced biological phosphate removal

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Authors: Dina M. Abd El-Aty, D. Aman, E. G. Zaki, Heba M. Salem

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A friendly environmental source of energy as hydrogen was produced by photo-hydrolysis of hydrogen storage material as sodium borohydride (NaBH4), which is non-toxic and stores a high percentage of hydrogen. The photoreaction was produced under visible light and nano-alumina as a catalyst. In this study, we use more economical and friendly environmental oil as a template to produce a nano-catalyst. The prepared catalyst was characterized by X-Ray diffraction, N2-adsorption-desorption, Fourier Transforms Infrared, Scanning Electron microscope and X-Ray Photoelectron Spectroscopy. Different parameters such as catalyst weight, NaBH4 weight and time of irradiation were studied to obtain a highly efficient photo-hydrolysis reaction. The reaction is pseudo-first order and the hydrogen production rate was determined as 1500 ml min-1 g-1 at the optimum conditions.

Keywords: photo-reaction, nano-alumina, hydrogen production, sodium borohydride, visible light

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Authors: Mohammad Ashraf, Kawther Mohamed

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This research tackles a new kind of additions (Nano Clay) and its effect on the features of concrete and both fresh and hardened cement mortar, as well as setting an optimal percentage of adding it to achieve the desired results and obtain on a strong concrete and mortar can be used for skyscrapers. The cementations additions are mineral materials in the form of a fine powder, added to concrete or cement mortar as partly cement substitutes, which means to be added instead of an equivalent amount of cement in order to improve and enhance some features of concrete or both the newly made and hardened cementations materials.

Keywords: nano clay in structure engineering, nanotechnology in construction industry, advanced additions in concrete, special concrete for skyscrapers

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Authors: Hallan Moura Ladeira, Carla Tatiana Mota Anflor

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The drilling process for bolted or riveted joints of components is very common in the naval, aeronautical, mechanical, and civil industries. In this context, the present work aims to study, through computer simulation, the influence of hole geometry (through, chamfered, and rounded) on crack propagation when submitted to static and dynamic loads. For the static crack evaluation, failure was considered when the stress intensity factor (FIT) exceeds the fracture toughness of the material (KIc). In the case of fatigue, the condition of the small crack tip plastification zone and the Paris Law were considered for determining region II of the dadN x ΔK curve. Initially, a parametric analysis of the hole geometry was performed to obtain a topology that would result in less discontinuity of the stress field and, consequently, less influence on static crack growth. The best performing topology was then used to study the fatigue crack growth rate considering the Paris Law. The numerical tests were performed on a 7075-T6 aluminum specimen resulting in dadN x ΔK curves in good agreement with the literature.

Keywords: holes, cracks, loading, fracture toughness

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Authors: V. Sivasubramanian, M. Jerold

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The advancement of adsorption is the development of nano-biocomposite for the sorption dyes and heavy metal ions. In fact, Nanoscale zerovalent iron (NZVI) is cost-effective reducing agent and a most reliable biosorbent for the dye biosorption. In this study, nano zero valent iron Sargassum swartzii (nZVI-SS) biocomposite, a novel marine algal based biosorbent, was used for the removal of simulated crystal violet (CV) in batch mode of operation. The Box-Behnen design (BBD) experimental results revealed the biosoprtion was maximum at pH 7.5, biosorbent dosage 0.1 g/L and initial CV concentration of 100 mg/L. Therefore, the result implies that nZVI-SS biocomposite is a cheap and most promising biosorbent for the removal of CV from wastewater.

Keywords: algae, biosorption, zero-valent, dye, waste water

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Authors: Brandon Foggo, Nanpeng Yu

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Power distribution circuits undergo frequent network topology changes that are often left undocumented. As a result, the documentation of a circuit’s connectivity becomes inaccurate with time. The lack of reliable circuit connectivity information is one of the biggest obstacles to model, monitor, and control modern distribution systems. To enhance the reliability and efficiency of electric power distribution systems, the circuit’s connectivity information must be updated periodically. This paper focuses on one critical component of a distribution circuit’s topology - the secondary transformer to phase association. This topology component describes the set of phase lines that feed power to a given secondary transformer (and therefore a given group of power consumers). Finding the documentation of this component is call Phase Identification, and is typically performed with physical measurements. These measurements can take time lengths on the order of several months, but with supervised learning, the time length can be reduced significantly. This paper compares several such methods applied to Phase Identification for a large range of real distribution circuits, describes a method of training data selection, describes preprocessing steps unique to the Phase Identification problem, and ultimately describes a method which obtains high accuracy (> 96% in most cases, > 92% in the worst case) using only 5% of the measurements typically used for Phase Identification.

Keywords: distribution network, machine learning, network topology, phase identification, smart grid

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Authors: Raj Kishore Swain, Kamdev Sethy, Sumanta Kumar Mishra

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Selenium is an essential trace element for the chicken with a variety of biological functions like growth, fertility, immune system, hormone metabolism, and antioxidant defense systems. Selenium deficiency in chicken causes exudative diathesis, pancreatic dystrophy and nutritional muscle dystrophy of the gizzard, heart and skeletal muscle. Additionally, insufficient immunity, lowering of production ability, decreased feathering of chickens and increased embryo mortality may occur due to selenium deficiency. Nano elemental selenium, which is bright red, highly stable, soluble and of nano meter size in the redox state of zero, has high bioavailability and low toxicity due to the greater surface area, high surface activity, high catalytic efficiency and strong adsorbing ability. To assess the effect of dietary nano-Se on performance and expression of gene in Vencobb broiler birds in comparison to its inorganic form (sodium selenite), four hundred fifty day-old Vencobb broiler chicks were randomly distributed into 9 dietary treatment groups with two replicates with 25 chicks per replicate. The dietary treatments were: T1 (Control group): Basal diet; T2: Basal diet with 0.3 ppm of inorganic Se; T3: Basal diet with 0.01875 ppm of nano-Se; T4: Basal diet with 0.0375 ppm of nano-Se; T5: Basal diet with 0.075 ppm of nano-Se, T6: Basal diet with 0.15 ppm of nano-Se, T7: Basal diet with 0.3 ppm of nano-Se, T8: Basal diet with 0.60 ppm of nano-Se, T9: Basal diet with 1.20 ppm of nano-Se. Nano selenium was synthesized by mixing sodium selenite with reduced glutathione and bovine serum albumin. The experiment was carried out in two phases: starter phase (0-3 wks), finisher phase (4-5 wk) in deep litter system. The body weight at the 5th week was best observed in T4. The best feed conversion ratio at the end of 5th week was observed in T4. Erythrocytic catalase, glutathione peroxidase and superoxide dismutase activity were significantly (P < 0.05) higher in all the nano selenium treated groups at 5th week. The antibody titers (log2) against Ranikhet diseases vaccine immunization of 5th-week broiler birds were significantly higher (P < 0.05) in the treatments T4 to T7. The selenium levels in liver, breast, kidney, brain, and gizzard were significantly (P < 0.05) increased with increasing dietary nano-Se indicating higher bioavailability of nano-Se compared to inorganic Se. The real time polymer chain reaction analysis showed an increase in the expression of antioxidative gene in T4 and T7 group. Therefore, it is concluded that supplementation of nano-selenium at 0.0375 ppm over and above the basal level can improve the body weight, antioxidant enzyme activity, Se bioavailability and expression of the antioxidative gene in broiler birds.

Keywords: chicken, growth, immunity, nano selenium

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Authors: Ghada Salem, Nihal Kabel

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Objective: This in vitro study was carried out to assess the microleakage properties of nano-filled glass ionomer in comparison to resin-reinforced glass ionomers. Material and Methods: 40 deciduous molar teeth were included in this study. Class-II cavity was prepared in a standard form for all the specimens. The teeth were randomly distributed into two groups (20 per group) according to the restorative material used either nano-glass ionomer or Photac Fill glass ionomer restoration. All specimens were thermocycled for 1000 cycles between 5 and 55 °C. After that, the teeth were immersed in 2% methylene blue dye then sectioned and evaluated under a stereomicroscope. Microleakage was assessed using linear dye penetration and on a scale from zero to five. Results: Two way ANOVA test revealed a statistically significant lower degree of microleakage in both occlusal and gingival restorations (0.4±0.2), (0.9±0.1) for nano-filled glass ionomer group in comparison to resin modified glass ionomer (2.3±0.7), (2.4±0.5). No statistical difference was found between gingival and occlusal leakage regarding the effect of the measured site. Conclusion: Nano-filled glass ionomer shows superior sealing ability which enables this type of restoration to be used in minimum invasive treatment.

Keywords: microleakage, nanoionomer, resin-reinforced glass ionomer, proximal cavity preparation

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Authors: Mehdi Ketabchi, Shallah Alijanlo

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The flue gas from fossil fuels combustion contains harmful pollutants dangerous for human health and environment. One of the air pollution control methods to restrict the emission of these pollutants is based on using the nanoparticle in adsorption process. In the present research, gamma nano-alumina particle is added to polyacrylonitrile (PAN) polymer through simple loading method, and the adsorption capacity of the wet spun fiber is investigated. The results of exposure the fiber to the acid gases including SO₂, CO, NO₂, NO, and CO₂ show the noticeable increase of gas adsorption capacity on fiber contains nanoparticle. The research has been conducted in Acrylic II Plant of Polyacryl Iran Corporation.

Keywords: acrylic fiber, adsorbent, wet spun, polyacryl company, nano gamma alumina

Procedia PDF Downloads 148

Authors: Yu-Shan Wu, Po-Liang Lai, I-Ming Chu

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Poly(methylmethacrylate)(PMMA) is the most frequently used bone void filler for vertebral augmentation in osteoporotic fracture. PMMA bone cement not only exhibits strong mechanical properties but also can fabricate according to the shape of bone defect. However, the adhesion between the PMMA-based cement and the adjacent bone is usually weak and as PMMA bone cement is inherently bioinert. The combination of bioceramics and polymers as composites may increase cell adhesion and improve biocompatibility. The nano-hydroxyapatite(HAP) not only plays a significant role in maintaining the properties of the natural bone but also offers a favorable environment for osteoconduction, protein adhesion, and osteoblast proliferation. However, defects and cracks can form at the polymer/ceramics interface, resulting in uneven distribution of stress and subsequent inferior mechanical strength. Surface-modified HAP nano-crystals were prepared by chemically grafting poly(ε-caprolactone)(PCL) on surface-modified nano-HAP surface to increase the affinity of polymer/ceramic phases .Thus, incorporation of surface-modified nano-hydroxyapatite (EC-HAP) may not only improve the interfacial adhesion between cement and bone and between nanoparticles and cement, but also increase biocompatibility. In this research, PMMA mixing with 0, 5, 10, 15, 20, 25 and 30 wt% EC-HAP were examined. MC3T3-E1 cells were used for the biological evaluation of the response to the cements in vitro. Morphology was observed using scanning electron microscopy (SEM). Mechanical properties of HAP/PMMA and EC-HAP/PMMA cement were investigated by compression test. Surface wettability of the cements was measured by contact angles.

Keywords: bone cement, biocompatibility, nano-hydroxyapatite, polycaprolactone, PMMA, surface grafting

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Authors: L. N. Shubha, M. Kalpana, P. Madhusudana Rao

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Polyaniline/gold (PANI/Au) nanocomposite was prepared by in-situ chemical oxidation polymerization method. The synthesis involved the formation of polyaniline-gold nanocomposite, by in-situ redox reaction and the dispersion of gold nano particles throughout the polyaniline matrix. The nanocomposites were characterized by XRD, FTIR, TEM and UV-visible spectroscopy. The characteristic peaks in FTIR and UV-visible spectra confirmed the expected structure of polymer as reported in the literature. Further, transmission electron microscopy (TEM) confirmed the formation of gold nano particles. The crystallite size of 30 nm for nanoAu was supported by the XRD pattern. Further, the A.C. conductivity, dielectric constant (€’(w)) and dielectric loss (€’’(w)) of PANI/Au nano composite was measured using impedance analyzer. The effect of doping on the conductivity was investigated. The antibacterial activity was examined for this nano composite and it was observed that PANI/Au nanocomposite could be used as an antibacterial agent.

Keywords: AC-conductivity, anti-microbial activity, dielectric constant, dielectric loss, polyaniline/gold (PANI/AU) nanocomposite

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Authors: Behzad Ahdiharab, Senol Baskaya, Tamer Calisir

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Heat exchangers are one of the most widely used systems in factories, refineries etc. In this study, natural convection heat transfer using nano-fluids in between two cylinders is numerically investigated. The inner and outer cylinders are kept at constant temperatures. One of the most important assumptions in the project is that the working fluid is non-Newtonian. In recent years, the use of nano-fluids in industrial applications has increased profoundly. In this study, nano-Newtonian fluids containing metal particles with high heat transfer coefficients have been used. All fluid properties such as homogeneity has been calculated. In the present study, solutions have been obtained under unsteady conditions, base fluid was water, and effects of various parameters on heat transfer have been investigated. These parameters are Rayleigh number (103 < Ra < 106), power-law index (0.6 < n < 1.4), aspect ratio (0 < AR < 0.8), nano-particle composition, horizontal and vertical displacement of the inner cylinder, rotation of the inner cylinder, and volume fraction of nanoparticles. Results such as the internal cylinder average and local Nusselt number variations, contours of temperature, flow lines are presented. The results are also discussed in detail. From the validation study performed it was found that a very good agreement exists between the present results and those from the open literature. It was found out that the heat transfer is always affected by the investigated parameters. However, the degree to which the heat transfer is affected does change in a wide range.

Keywords: heat transfer, circular space, non-Newtonian, nano fluid, computational fluid dynamics.

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Authors: Fernando G. Torres, Omar P. Troncoso

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Quercetin is a naturally occurring polyphenol found in many vegetables, such as onion, with antioxidant properties. It is a dietary component with a documented role in reducing different human cancers. However, its low bioavailability, poor water solubility, and chemical instability limit its applications. Different nano-delivery systems such as nanoparticles, micelles, and nanohydrogels have been studied in order to improve the bioavailability of quercetin. Nanoparticles based on natural polymers such as starch have the advantage of being biocompatible, biodegradable, and non-toxic. In this study, quercetin was loaded into starch nanoparticles using a nanoprecipitation method. Different routes, using sodium tripolyphosphate and Tween® 80 as tensioactive agents, were tested in order to obtain an optimized starch-based nano-delivery system. The characterization of the nanoparticles loaded with quercetin was assessed by Fourier Transform Infrared Spectroscopy, Dynamic Light Scattering, Zeta potential, and Differential scanning calorimetry. UV-vis spectrophotometry was used to evaluate the loading efficiency and capacity of the samples. The results showed that starch-based systems could be successfully used for the nano-delivery of quercetin.

Keywords: starch nanoparticles, nanoprecipitation, quercetin, biomedical applications

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Authors: Ahmed Khalil

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The discoveries in material sciences create an impulse in renewable energy transmission. Application techniques become more accessible by applied sciences. Variety of materials, application methods, and performance analyzing techniques can convert daily life functions to energy sources. These functions not only include natural sources like sun, wind, or water but also comprise the motion of tools used by human beings. In line with this, vehicles' motion, speed and weights come to the scene as energy sources together with piezoelectric nano-generators beneath the roads. Numerous application examples are put forward with repeated average performance, versus the differentiating challenges depending on geography and project conditions. Such holistic approach provides way for feed backs on research and improvement process of nano-generators beneath asphalt roads. This paper introduces the specific application methods of piezoelectric nano-generator beneath asphalt roads of Ahmadi Township in Kuwait.

Keywords: nano-generator pavements, piezoelectric, renewable energy, transducer

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Authors: Satyananda Behera, Ritwik Sarkar

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In iron and steel industries, MgO–C refractories are widely used in basic oxygen furnaces, electric arc furnaces and steel ladles due to their excellent corrosion resistance, thermal shock resistance, and other excellent hot properties. Conventionally magnesia carbon refractories contain about 8-20 wt% of carbon but the use of carbon is also associate with disadvantages like oxidation, low fracture strength, high heat loss and higher carbon pick up in steel. So, MgO-C refractory having low carbon content without compromising the beneficial properties is the challenge. Nano carbon, having finer particles, can mix and distribute within the entire matrix uniformly and can result in improved mechanical, thermo-mechanical, corrosion and other refractory properties. Previous experiences with the use of nano carbon in low carbon MgO-C refractory have indicated an optimum range of use of nano carbon around 1 wt%. This optimum nano carbon content was used in MgO-C compositions with flaky graphite followed by aluminum and silicon metal powder as an anti-oxidant. These low carbon MgO-C refractory compositions were prepared by conventional manufacturing techniques. At the same time 16 wt. % flaky graphite containing conventional MgO-C refractory was also prepared parallel under similar conditions. The developed products were characterized for various refractory related properties. Nano carbon containing compositions showed better mechanical, thermo-mechanical properties, and oxidation resistance compared to that of conventional composition. Improvement in the properties is associated with the formation of in-situ ceramic phase-like aluminum carbide, silicon carbide, and magnesium aluminum spinel. Higher surface area and higher reactivity of N220 nano carbon black resulted in greater formation in-situ ceramic phases, even at a much lower amount. Nano carbon containing compositions were found to have improved properties in MgO-C refractories compared to that of the conventional ones at much lower total carbon content.

Keywords: N220nano carbon black, refractory properties, conventionally manufacturing techniques, conventional magnesia carbon refractories

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Authors: M.S. El-Feky, Passant Youssef, Mohamed I. Serag

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nowadays, nanotechnology is the main trend of research in different areas due to the new potential of using nanometer materials sized less than 100nm. Nanomaterials are needed in cement composites to act as bridging for Nano and micro-cracks to increase tensile strength, reduce the permeability of gases and water in concrete to solve corrosion problem, react with excess Calcium Hydroxide, produce additional C-S-H, act as filler materials to densify the cement matrix and increase its mechanical properties. The present study focuses on the effectiveness of super-plasticizers and ultrasonic processing on the dispersion of Carbon Nanotube at first in water and then in cement composites in combination with Nano silica to enhance the mechanical properties of cement composites. A qualitative analysis using a compressive strength test is conducted with a view to investigate the influence of different dispersion techniques on the mechanical properties of cement composites containing Carbon Nanotube (CNT) and Nano Silica (NS) particles with different percentages. In addition, micro-structural analysis was carried out to understand the surface morphology and microstructure of cement composites with different dosages of NS addition. The investigational study results showed that the combination of NS with a low amount of CNT had a positive effect on the hydration reaction; on the other hand, the combination of CNT and a high amount of NS had a negative effect on the hydration reaction. The compressive strength can be improved by optimum combination 0.02% CNT and 1% NS with gain in strength by 72% and 35% after 7 and 28 days compared to control samples; these results were with an agreement with the morphology structure of composites using microstructure analysis.

Keywords: nano silica, dispersion, sonication, carbon nano tubes

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Authors: Tasnuva Tamanna, Aimin Yu

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Application of nanoscience in biomedical field has come across as a new era. This study involves the synthesis of nano drug carrier with antibiotic loading. Based on the founding that polydopamine (PDA) nanoparticles could be formed via self-polymerization of dopamine at alkaline pH, one-step synthesis of rifampicin coupled polydopamine (PDA-R) nanoparticles was achieved by adding rifampicin into the dopamine solution. The successful yield of PDA nanoparticles with or without the presence of rifampicin during the polymerization process was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. Drug loading was monitored by UV-vis spectroscopy and the loading efficiency of rifampicin was calculated to be 76%. Such highly capacious nano-reservoir was found very stable with little drug leakage at pH 3.

Keywords: drug loading, nanoparticles, polydopamine, rifampicin

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Authors: Jia-Ling Ho, Xiu-Ru Zhang, Zwe-Ling Kong

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Diabetes mellitus (DM) is a major health problem that affects patients’ life quality throughout the world due to its many complications. It characterized by chronic hyperglycemia with oxidative stress, which impaired male reproductive function. Fibroblast growth factor 21 (FGF21) is a metabolic regulator that is required for normal spermatogenesis and protects against diabetes-induced germ cell apoptosis. Echinacea purpurea ethanol extract (EE), which contain phenolic acid and isobutylamide, had been proven to have antidiabetic property. Silica-chitosan nanoparticles (Nano-CS) has drug delivery and controlled release properties. This study aims to investigate whether silica-chitosan nanoparticles encapsulated EE (Nano-EE) had more ameliorating male infertility by analyzing the effect of testicular FGF21. The Nano-EE was characterized before used to treatment the diabetic rat model. Male Sprague-Dawley (SD) rats were obtained and divided into seven groups. A group was no induced Streptozotocin (STZ), marked as normal group. Diabetic rats were induced into diabetes by STZ (33 mg/kg). A diabetic group was no treatment with sample (diabetic control group), and other groups were treatment by Nano-CS (465 mg/kg), Nano-EE (93, 279, 465 mg/kg), and metformin (Met) (200 mg/kg) used as reference drug for 7 weeks. Our results indicated that the average nanoparticle size and zeta potential of Nano-EE were 2630 nm and -21.3 mV, respectively. The encapsulation ratio of Nano-EE was about 70%. It also confirmed the antioxidative activity was unchanged by comparing the DPPH and ABTS scavenging of Nano-EE and EE. In vivo test, Nano-EE can improve the STZ induced hyperglycemia, insulin resistance, and plasma FGF21 levels. Nano-EE has increased sperm motility, mitochondria membrane potential (MMP), plasma testosterone level, and reduction of abnormal sperm, nitric oxide (NO), superoxide production as well as reactive oxygen species (ROS). In addition, in plasma antioxidant enzymes glutathione peroxidase (GPx) and superoxide dismutase (SOD) was increased whereas pro-inflammatory cytokines TNF-α, and IL-1β were decreased. Further, in testis, protein content of FGF21, PGC-1α, and SIRT1 were improved. Nano-EE might improve diabetes-induced down-regulation of testicular FGF21 and SIRT1/PGC-1α signaling hence maintain spermatogenesis.

Keywords: diabetes mellitus, Echinacea purpurea, reproductive dysfunction, silica-chitosan nanoparticles

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Authors: Mahdi Almaky

Abstract:

Conducting polymer of N-(3-pyrrol-1-yl-propyl)-2,2`-bipyridinium hexafluoro-phosphate (PPBH) was prepared via chemical and electrochemical polymerization methods. The bulk polymer showed conductivity in the order of 10-12 S cm-1. DNA-templated polymer nano wires of PPBH (PolyPPBH-DNA) have been chemically prepared then used as templates to direct the formation of metal nanowires (Cu) in order to enhance the electrical properties of the polymer/DNA wires. The chemical structures, morphology and the electrical characterisation of the as obtained structures have been characterized through spectroscopic (FTIR, UV-vis and XPS), single-crystal X-ray diffraction and microscopic (AFM, EFM and c-AFM) techniques. The morphology of the nanomaterials has been observed by AFM; showing the nanowires are uniform and continuous. The polymer conductivity was slightly improved after metallization. The conductivity of Cu-PolyPPBH-DNA nanowires was estimated to be 7.1x10-2 S cm-1. This conductivity is slightly higher than the conductivity of PolyPPBH-DNA nano wires (2.0 x 10-2 S cm-1), but it is lower than the measurements for PPy/DNA nano wires (2.1 x 10-1 S cm-1) prepared and measured by using c-AFM probe. These results reflect the large effect of the chemical structure (N-substitution) on the electrical properties of these polymers by reducing the extended conjugation.

Keywords: DNA, template, nano wires, N-Alkylatedpyrrole, copper

Procedia PDF Downloads 394

Authors: Asiful Hossain Seikh, Mohammad Asif Alam, Ubair Abdus Samad, Jabair A. Mohammed, S. M. Al-Zahrani, El-Sayed M. Sherif

Abstract:

In this current investigation, aliphatic amine-cured diglycidyl ether of bisphenol-A (DGEBA) based epoxy coating was mixed with certain weight % hardener polyaminoamide (1:2) and was coated on carbon steel panels with and without 1% nano crystalline Al powder. The corrosion behavior of the coated samples were investigated by exposing them in the salt spray chamber, for 500 hours. According to ASTM-B-117, the bath was kept at 35 °C and 5% NaCl containing mist was sprayed at 1.3 bars pressure. Composition of coatings was confirmed using Fourier-transform infrared spectroscopy (FTIR). Electrochemical characterization of the coated samples was also performed using potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS) technique. All the experiments were done in 3.5% NaCl solution. The nano Al coated sample shows good corrosion resistance property compared to bare Al sample. In fact after salt spray exposure no pitting or local damage was observed for nano coated sample and the coating gloss was negligibly affected. The surface morphology of coated and corroded samples was studied using scanning electron microscopy (SEM).

Keywords: epoxy, nano aluminium, potentiodynamic polarization, salt spray, electrochemical impedence spectroscopy

Procedia PDF Downloads 115

Authors: Asha Gupta, Ramandeep Kaur

Abstract:

The purpose of this paper is to study a class of closed sets, called generalized pre-closed sets with respect to an ideal (briefly Igp-closed sets), which is an extension of generalized pre-closed sets in general topology. Then, by using these sets, the concepts of Igp- compact spaces along with some classes of maps like continuous and closed maps via ideals have been introduced and analogues of some known results for compact spaces, continuous maps and closed maps in general topology have been obtained.

Keywords: ideal, gp-closed sets, gp-closed maps, gp-continuous maps

Procedia PDF Downloads 179

Authors: N. Marzban, J. K. Heydarzadeh M. Pourmohammadbagher, M. H. Hatami, A. Samia

Abstract:

A nano-alumina-zirconia composite catalyst was synthesized by a simple aqueous sol-gel method using AlCl₃.6H₂O and ZrCl₄ as precursors. Thermal decomposition of the precursor and subsequent formation of γ-Al₂O₃ and t-Zr were investigated by thermal analysis. XRD analysis showed that γ-Al₂O₃ and t-ZrO₂ phases were formed at 700 °C. FT-IR analysis also indicated that the phase transition to γ-Al₂O₃ occurred in corroboration with X-ray studies. TEM analysis of the calcined powder revealed that spherical particles were in the range of 8-12 nm. The nano-alumina-zirconia composite particles were mesoporous and uniformly distributed in their crystalline phase. In order to measure the catalytic activity, esterification reaction was carried out. Biodiesel, as a renewable fuel, was formed in a continuous packed column reactor. Free fatty acid (FFA) was esterified with ethanol in a heterogeneous catalytic reactor. It was found that the synthesized γ-Al₂O₃/ZrO₂ composite had the potential to be used as a heterogeneous base catalyst for biodiesel production processes.

Keywords: nano alumina-zirconia, composite catalyst, thin film, biodiesel

Procedia PDF Downloads 204