41 research outputs found
Effect of frequency on fatigue crack growth behavior of magnesium alloy AZ61 under immersed 3.5mass% NaCl environment
No full textStructural and Electrical Properties of Graphene Oxide/Nickel Oxide Based Polymer Nanocomposite
No full textSolid state Bonding of Superplastic Duplex Stainless Steel to Carbon Steel and Fatigue Strength of Joint
No full textTransformer oils-based graphene quantum dots nanofluid as a new generation of highly conductive and stable coolant
No full textA Study on the Effect of Gold Nanoparticles for Dye Sensitized Solar Cell Using Hibiscus Rosa-Sinensis as Photosensitizer
Get PDFDye-sensitized solar cells (DSSC) mainly uses organic components as an alternative way of light harvesting element to replace the traditional silicon solar cells. Natural dye alternatively is being used as sensitizers to overcome the limitation of inorganic ruthenium dye which contains heavy metal. In this study, DSSC is expected to enhance its optical properties and light absorption by implementing gold (Au) nanoparticles. Various natural and organic sources can be extracted and acted as a photosensitizer to trap solar energy. Fresh Hibiscus Rosa-Sinensis flowers are one of the good candidates to give higher light absorption in DSSC. The characteristics of the dye photosensitizer will be observed under UV-Vis-NIR Spectrophotometer. The efficiency of complete DSSC will be determined by using LIV tester. An attempt to enhance light-harvesting efficiency and hence the light to current conversion efficiency by mixing Au nanoparticles TiO? QUOTE paste. Au nanoparticle was selected because it can act as a medium between the dye and Ti QUOTE O? to increase the electron transmission speed. The Hibiscus dye in DSSC achieved an efficiency of 0.14%. However, the efficiency reduced to 0.000178% as Au NPs was added. The effects of the addition of Au nanoparticles are discussed. 
Effects of functionalized carbon nanofillers on the spectral selectivity behavior of aluminum nanocomposites for solar absorber applications
No full textThe effects of functionalized multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) on the spectral selectivity behavior of aluminum (Al) nanocomposites were investigated in this study. The attachment of the carboxylic (COOH) functional group on the surface of the carbon nanofillers was confirmed by Fourier transform infrared spectroscopy. The pristine and functionalized MWCNTs and GNPs were introduced into pure Al powder at different concentrations (5, 10, and 15 wt%) to produce Al–MWCNT–GNP and Al–MWCNTCOOH–GNPCOOH nanocomposites. The results show that the dispersion of the carbon nanofillers is better and the spectral selectivity ratios are higher for the Al–MWCNTCOOH–GNPCOOH nanocomposites compared with those for Al–MWCNT–GNP nanocomposites. In addition, the light absorption is significantly enhanced in the ultraviolet, visible, and near-infrared regions (200–2500 nm) whereas the reflectance is significantly enhanced in the near-infrared, mid-infrared, and far-infrared regions (3000–14 000 nm) for the Al–MWCNTCOOH–GNPCOOH nanocomposites. The highest spectral selectivity ratio (27.41) is attained for the Al nanocomposite with 2.5 wt% MWCNTCOOH and 2.5 wt% of GNPCOOH
THEORETICAL APPROACHES TO ASSESSING THE EFFICIENCY OF FOREIGN INVESTMENTS
No full textThis article systematically analyzes theoretical approaches, assessment methods and international methodologies for assessing the efficiency of foreign investments. In particular, the assessment mechanisms developed by leading organizations such as UNIDO, the World Bank, Little-Mirrless, Cost-Benefit Analysis, Ernst & Young are studied on a comparative basis. The author substantiates with theoretical arguments that foreign investments are not only a financial flow, but also a major source of technological transfer, innovation, market relations and modern management experience. The contribution of foreign investments to economic development is revealed within the framework of theories of international investment integration, risk-return model and investment portfolio approaches. At the same time, institutional and infrastructural recommendations aimed at increasing the efficiency of foreign investments are presented on the example of Uzbekistan. The results of the study allow using them as a theoretical and practical resource for assessing foreign investments and their more targeted management
Effects of Oil Palm Empty Fruit Bunch Fiber on Electrical and Mechanical Properties of Conductive Filler Reinforced Polymer Composite
No full textLow density polyethylene (LDPE), carbon black (CB), and oil palm empty fruit bunch (OPEFB) fiber composites were prepared by melt blending and compression molded into sheets. The effects of incorporated fibers on the electrical conductivity, thermal conductivity, tensile properties, and thermal degradation of the composites were investigated. FTIR results suggest that the OPEFB fibers interact poorly with the polymer matrix and lead to a decrease in mechanical properties. The electrical conductivity of the composites decreased with increasing OPEFB fiber content. Despite the slight decline in conductivity, the composites still were sufficiently conductive relative to applications such as sensors and electromagnetic shielding after the fiber addition. Reduction in thermal conductivity by as much as 10.9% was observed with the addition of 20% OPEFB fiber into LDPE/CB composites. The thermal stability of LDPE/CB/OPEFB fiber composites decreased with increasing fiber content because of the low thermal stability of the incorporated natural fiber
Preparation and Characterization of Poly(lactic Acid)-based Composite Reinforced with Oil Palm Empty Fruit Bunch Fiber and Nanosilica
No full textThe properties of poly(lactic acid) (PLA) bio-composite films reinforced with oil palm empty fruit bunch (OPEFB) fiber and nanosilica were studied in this work. The composite films were prepared via the solvent casting method. The composites were characterized via Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy, field-emission scanning electron microscopy (FESEM), tensile testing, and X-ray diffraction (XRD). Ultraviolet visible spectroscopy results revealed that the PLA-based composites and neat PLA had similar light transmittances of approximately 89%. The FTIR and FESEM results showed that OPEFB fibers and nanosilica were embedded into the PLA matrix. The tensile strength of the composites with addition of nanosilica increased with an increasing fiber load content. The XRD analysis showed that the addition of organic or inorganic silica reduced the crystallinity of the composites. The water vapor permeability test results indicated that the inorganic silica decreased the diffusion rate of water molecules through the polymer film. The OPEFB-reinforced PLA blend with additional organic silica exhibited a higher thermal stability than the composites reinforced with inorganic silica
