90 research outputs found
Schottkyjeve diode proizvedene na elektro-kemijski raslim nano- i mikro-stapićima
Aligned ZnO nanorods grown on polycrystalline substrates have promising optoelectronic applications. Novel samples with such structures were electrodeposited on stainless foil from a ZnCl2 route. Well-aligned and free-standing hexagonal nanorods with 100 nm diameter and closely-packed microrods with a diameter above 1 µm could be grown normal to the substrate. The optical transition energies (absorption and emission) of samples were determined by transmittance and photoluminescence spectroscopy. We report on the fabrication of high-quality AgSchottky diodes formed on the oxygen-treated (002) facets of microrods. Diodes with a large barrier height (1.1 eV), low saturation current density (1.3 pA/cm2 ) and high rectification factor (5 × 106 at ±3 V) were fabricated. The concentration and mobility of free electrons in oxygen-treated microrods were measured as 1.4 × 1014 cm−3 and 1.2 cm2V−1 s −1 , respectively.Poredani nanoštapići ZnO, narasli na polikristalnoj podlozi, mogli bi naći primjene u optoelektroničkim napravama. Pripremili smo nove uzorke takvih naprava elektro-taloženjem na listiće nerđajućeg čelika primjenom ZnCl2. Postigli smo dobro odvojene i poredane heksagonalne nano-štapiće promjera 100 nm i gusto poredane mikro-štapiće promjera većeg od 1 µm, narasle okomito na podlogu. Primjenom propusne i fotoluminescentne spektroskopije odredili smo (apsorpcijske i emisijske) prijelazne energije uzoraka. Izvješćujemo o izradi visoko-kvalitetnih Ag-Schottky dioda izvedenih na (002) plohama mikro-štapića nakon obrade kisikom. Načinili smo diode s visokim protunaponom (1.1 eV), malom gustoćom struje zasićenja (1.3 pA/cm2 ) i velikim faktorom ispravljanja (5 × 106 na ±3 V). Odredili smo koncentraciju i pokretljivost slobodnih elektrona u kisikom-obrađenim mikro-štapićima od 1.4 × 1014 cm−3 odnosno 1.2 cm2V−1 s −1
Identification of Commercial Oxo-Biodegradable Plastics: Study of UV Induced Degradation in an Effort 1 to Combat Plastic Waste Accumulation
About 50% of plastics is discarded after only single use which creates major environmental burdens. End of life 14 single-use items such as carrier bags constitute a large proportion of the litter found in marine and terrestrial 15 environments alike. The main objective of the current work was to investigate the response of an oxo-16 biodegradable commercial plastic film product to photo-degradation using accelerated weathering, verifying the 17 claim of its biodegradability and suitability as an eco-friendly product. The test specimens used were white to 18 transparent commercial grade plastic bags of PE origin acquired from an international franchise of household 19 goods, which were claimed to be of oxo-biodegradable nature. This study is also geared towards the 20 appropriateness of such products to reduce plastic waste accumulation in urban environments. The film samples 21 were exposed to weathering up to 20 continuous days to determine their degradability and assess their thermal 22 properties as a means to determine impact of UV induced oxo-biodegradation. Haze (%), light transmission (%) 23 and the total change in colour (ΔE) were measured as indicators to the degradation profile of the polymeric 24 materials, in addition to tensile pull mechanical properties and thermal stability. The melting peak indicates the 25 melting point (Tm) of the polymer and with exposure to weathering it showed a slight decrease from 105 to 26 102oC indicating that biodegradation mechanism was triggered. The reduction is strain at rupture was also 27 indicative of a loss in crystalline structure, coupled with Young’s modulus increase throughout weathering 28 exposure tests
Bioprospecting autochthonous marine microalgae strain from the Arabian Gulf Seawater, Kuwait for biofuel feedstocks
Bioprospecting programs are the key to increasing the current portfolio of indigenous microalgal strains accessible for different applications in microalgal biotechnology. In this work, nine fast-growing microalgal strains isolated from Kuwait's Arabian/Persian Gulf coastal waters were evaluated for their potential as biofuel feedstocks. 18S rRNA gene sequencing showed that the strains belong to five different genera: Chlorella, Nannochloris, Scenedesmus, Tetraselmis, and Nannochloropsis. In terms of the total lipid content, in comparison to the other strains, Tetraselmis sp. KUBS13G and Tetraselmis sp. KUBS16G displayed higher lipid contents of 29.56% dry weight (DW) and 26.13% DW, respectively, dominated by palmitic and oleic acids. Fuel properties calculated from the fatty acid methyl esters (FAMES) by empirical equations were compared with EN14214 (European) and ASTM D6751--02 (American) biodiesel standards. Multicriteria decision analysis (MCDA) methods, such as the Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GALA), were used to select suitable microalgae for biofuel feedstock based on their biodiesel fuel properties. Overall, the results suggested that the indigenous microalgal strain Tetraselmis, particularly Tetraselmis sp. KUBS37G, and Scenedesmus sp. KUB Sl7R are the most suitable strains for biofuel feedstock owing to their improved fuel properties, such as density (rho) (0.88 g cm-3), low kinematic viscosity (3.1 mm2 s-1), high cetane number (54 and 56, respectively), high oxidation stability (14.6 hr and 14.8 hr), and cold filter plugging point (1.0 degrees C and -6.1 degrees C).info:eu-repo/semantics/publishedVersio
Hierarchically Porous Gd3+-Doped CeO2 Nanostructures for the Remarkable Enhancement of Optical and Magnetic Properties
Rare earth ion-doped CeO2 has attracted more and more attention because of its special electrical, optical, magnetic, or catalytic properties. In this paper, a facile electrochemical deposition route was reported for the direct growth of the porous Gd-doped CeO2. The formation process of Gd-doped CeO2 composites was investigated. The obtained deposits were characterized by SEM, EDS, XRD, and XPS. The porous Gd3+- doped CeO2 (10 at% Gd) displays a typical type I adsorption isotherm and yields a large specific surface area of 135 m2/g. As Gd3+ ions were doped into CeO2 lattice, the absorption spectrum of Gd3+-doped CeO2 nanocrystals exhibited a red shift compared with porous CeO2 nanocrystals and bulk CeO2, and the luminescence of Gd3+-doped CeO2 deposits was remarkably enhanced due to the presence of more oxygen vacancies. In addition, the strong magnetic properties of Gd-doped CeO2 (10 at% Gd) were observed, which may be caused by Gd3+ ions or more oxygen defects in deposits. In addition, the catalytic activity of porous Gd-doped CeO2 toward CO oxidation was studied
Water Solubilization Using Nonionic Surfactants from Renewable Sources in Microemulsion Systems
In this study the effect of temperature, NaCl and oils (hydrocarbons: C8–C16) on the formation and solubilization capacity of the systems of oil/monoacylglycerols (MAG):ethoxylated fatty alcohols (CEO20)/propylene glycol (PG)/water was investigated. The effects of the surfactant mixture on the phase behavior and the concentration of water or oil in the systems were studied at three temperatures (50, 55, 60 °C) and with varied NaCl solutions (0.5; 2; 11%). Electrical conductivity measurement, FTIR spectroscopy and the DSC method were applied to determine the structure and type of the microemulsions formed. The dimension of the microemulsion droplets was characterized by dynamic light scattering. It has been stated that the concentration of CEO20 has a strong influence on the shape and extent of the microemulsion areas. Addition of a nonionic surfactant to the mixture with MAG promotes an increase in the area of microemulsion formation in the phase diagrams, and these areas of isotropic region did not change considerably depending on the temperature, NaCl solution and oil type. It was found that, depending on the concentration of the surfactant mixture, it was possible to obtain U-type microemulsions with dispersed particles size distribution ranging from 25 to 50 nm and consisting of about 30–32% of the water phase in the systems. The conditions under which the microemulsion region was found (electrolyte and temperature—insensitive, comparatively low oil and surfactant concentration) could be highly useful in detergency
Pure and multi metal oxide nanoparticles: synthesis, antibacterial and cytotoxic properties
Metal oxide semiconducting interfacial layers for photovoltaic and photocatalytic applications
Efficient one-pot synthesis of antimony-containing mesoporous tin dioxide nanostructures for gas-sensing applications
- …