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Manufacturing Technologies of Finned Tubes

References 1. Breeze P.: Raising steam plant efficiency - Pushing the steam cycle boundaries. PEI Magazine 20(2012). 2. Huseman R.: Advanced (700oC) PF Power Plant. A Clean Coal European Technology. Advanced Material for AD700 Boilers, Cesi Auditorium, Milano, 2005. 3. Najgebauer E., Patrycy A.: Commitments of Polish energy to the EU. www.geoland.pl. 4. Dziemidowicz Z., Szyszka P., Krupa I.: Power units on the horizon. The technical requirements of new generation units at PGE Power Plant

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Development of sol-gel derived gahnite anti-reflection coating for augmenting the power conversion efficiency of polycrystalline silicon solar cells

Abstract

The present research is focused on developing ZnAl2O4 (gahnite) spinel as an antireflection coating material for enhanced energy conversion of polycrystalline silicon solar cells (PSSC). ZnAl2O4 has been synthesized using dual precursors, namely aluminum nitrate nonahydrate and zinc nitrate hexahydrate in ethanol media. Diethanolamine has been used as a sol stabilizer in sol-gel process for ZnAl2O4 nanosheet fabrication. ZnAl2O4 nanosheet was deposited layer-by-layer (LBL) on PSSC by spin coating method. The effect of ZnAl2O4 coating on the physical, electrical, optical properties and temperature distribution in PSSC was investigated. The synthesized antireflection coating (ARC) material bears gahnite (ZnAl2O4) spinel crystal structure composed of two dimensional (2D) nanosheets. An increase in layer thickness proves the LBL deposition of ARC on the PSSC substrate. The ZnAl2O4 2D nanosheet comprising ARC on the PSSC was tested and it exhibited a maximum of 93 % transmittance, short-circuit photocurrent of 42.364 mA/cm2 and maximum power conversion efficiency (PCE) 23.42 % at a low cell temperature (50.2 °C) for three-layer ARC, while the reference cell exhibited 33.518 mA/cm2, 15.74 % and 59.1 °C, respectively. Based on the results, ZnAl2O4 2D nanosheets have been proven as an appropriate ARC material for increasing the PCE of PSSC.

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Efficiency enhancement of natural dye sensitized solar cell by optimizing electrode fabrication parameters

Abstract

Efficiency of dye-sensitized solar cell (DSSC) depends on several interrelated factors such as type and concentration of dye, type and thickness of photoelectrode and counter electrode. Optimized combination of these factors leads to a more efficient cell. This paper presents the effect of these parameters on cell efficiency. TiO2 nanoporous thin films of different thicknesses (5 μm to 25 μm) were fabricated on indium doped tin oxide (ITO) coated glass by doctor blading method and characterized by inverted microscope, stylus surface profiler and scanning electron microscope (SEM). Natural organic dye of different concentrations, extracted from turmeric, was prepared with ethanol solvent. Different combinations of dye concentrations and film thicknesses along with different types of carbon catalyst have been investigated by I-V characterization. The result shows that the cell made of a counter electrode catalyst material prepared by candle flame carbon combined with about 15 μm thick photoelectrode and 100 mg/mL dye in ethanol solvent, achieves the highest efficiency of 0.45 %, with open circuit voltage of 566 mV and short circuit current density of 1.02 mA/cm2.

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A novel photoelectrode of NiO@ZnO nanocomposite prepared by Pechini method coupled with PLD for efficiency enhancement in DSSCs

Abstract

The dye-sensitized solar cells made of NiO@ZnO nanoparticles were synthesized by a novel Pechini route using different NiO molar concentration ratios. The thermal, structural morphological, optical and electrical properties of the prepared samples were investigated using thermal gravimetric analysis and differential scanning calorimetery (TGA/DSC), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), FT-IR and Raman spectroscopy, UV-diffuse reflectance (UV-DRS), photoluminescence (PL) and current-voltage (I-V) measurements. The success of doping process was confirmed by the XRD patterns, which revealed the existence of new peak at 43.2° corresponding to secondary phase NiO. UV spectra exhibited red shifts in NiO doped ZnO NCs and PL spectra showed strong emission band at 355 nm. The doping of ZnO with NiO was intended to enhance the surface defects of ZnO. The current-voltage measurements showed an improvement of the short circuit photocurrent (Jsc) and fill factor (FF) and a decrease in the open circuit voltage (VOC) for dye-sensitized solar cell (DSSC) based on NiO-ZnO NCs. A clear enhancement in efficiency of DSSC from 1.26±0.10 % for pure ZnO to 3.01±0.25 % for NiO-ZnO NCs at the optimum doping with 1.5 mol% of NiO to ZnO (ZN1.5) was observed. The obtained material can be a suitable candidate for photovoltaic applications.

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Quantum chemical study of organic inhibitors of corrosion and hydrogen absorption An investigation of the mechanism of bainite transformation in experimental 0.2c-1v-2mn steel An investigation of the mechanism of bainite transformation in experimental 0.2c-1v-2mn steel

Absorption Efficiency // Eurocorrosion-94: Conference Papers. Bournemouth. 1994. Vol. 3, pp. 94-100. 3. Beloglazov S.M., Beloglazov G.S. Inhibitors of Steel Corrosion and Hydrogen Adsorption in Two-Phase System of Gas Pipelines // Abstracts: 3rd European Federation of Corrosion Workshop on Microbial Corrosion / Estoril Portugal, March 1994, pp. 64. 4. Beloglazov S.M., Beloglazov G.S., Myamina A.A. Corrosion and Hydrogen Absorption Inhibitors with Biocyde Action Against Sulphate Reducing Bacteria // Proc.: 46th Ann. Meeting Int. Soc. of

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Structure and Properties of Polyacrylonitrile/Polystyrene and Carbon Nanoparticle-Based Nanocomposite Foams

Structure of Composite Fibers. Polymers 10 (2018) 186. 11. Chen, Y., Wang, Y., Zhang, H.B., Li, X., Gui, C.X., Yu, Z.Z.: Enhanced electromagnetic interference shielding efficiency of polystyrene/graphene composites with magnetic Fe 3 O 4 nanoparticles. Carbon 82 (2015) 67-76. 12. Min, Z., Yang, H., Chen, F., Kuang, T.: Scale-up production of lightweight high-strength polystyrene/carbonaceous filler composite foams with high-performance electromagnetic interference shielding. Materials Letters 230 (2018) 157-160. 13. Wang, C., Xue, T., Dong, B., Wang, Z

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Graphene as a Material for Solar Cells Applications

A., Improvement of graphene-Si solar cells by embroidering grapheme with a carbon nanotube spider-web; Nano Energy 2015 - article in press. 31. Chandramika Bora, Chandrama Sarkar, Kiron J. Mohan, Swapan Dolui; Polythiophene /graphene composite as a highly efficient platinum-free counter electrode in dye-sensitized solar cells , Electrochimica Acta 03/2015; 157. 32. Yan H., Wang J., Feng B, Duan K, Weng J., Graphene and Ag nanowires co-modified photoanodes for high-efficiency dye-sensitized solar cells, Solar Energy 122 (2015), 966

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Bacterial Nanocellulose as a Microbiological Derived Nanomaterial

Abstract

Bacterial nanocellulose (BNC) is a nanofibrilar polymer produced by strains such as Gluconacetobacter xylinus, one of the best bacterial species which given the highest efficiency in cellulose production. Bacterial cellulose is a biomaterial having unique properties such as: chemical purity, good mechanical strength, high flexibility, high absorbency, possibility of forming any shape and size and many others. Such a large number of advantages contributes to the widespread use of the BNC in food technology, paper, electronic industry, but also the architecture in use. However, the greatest hopes are using the BNC in medicine. This text contains information about bacterial nanocellulose, its specific mechanical and biological properties and current applications.

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Perspectives of Materials for Fin Tubes

ABSTRACT

Modern design solutions of power boiler using the welded fin tubes for heat exchangers. Depending on thermal parameters (pressure and temperature), the heat transfer fluid and flue gas these constructions can be preheater, economizers or superheaters. Their use can significantly increase the energy efficiency of boilers. For the manufacture of welded fin tubes are used non-alloy steels and low-alloy C-Mo, C-Cr-Mo. Analysis of project assumptions supercritical blocks indicates that the range of conventional steel for power and martensitic steels has been depleted. Designing higher performance outlet of steam to 720°C and 35MPa requires the use of austenitic steels and nickel alloys. These materials are not easily available and not fully recognized, both technologically and in terms of materials, especially in the area of their weldability. In this work, performed the review of probably directions of development of materials for the finned tubes, with a particular focus on laser welding technology.

Open access
Fracture of Aluminium Joints Bonded with Epoxy Adhesive Reinforced by MMT Nanoparticles

Fracture of Aluminium Joints Bonded with Epoxy Adhesive Reinforced by MMT Nanoparticles

Crack propagation behavior was studied for aluminium/aluminum adhesive joints bonded with two epoxy adhesives: pure and reinforced with clay nanoparticles. The focus was also on the novel use of the constant displacement rate test to study adhesion/adhesives efficiency. The epoxy systems studied were: Epidian E6 produced from bisphenol A and epichlorohydrin, ("Organika -Sarzyna" Poland); pure or strengthened with montmorillonit nanoparticles (MMT). Crack growth rate was estimated for two displacement rates. The nanoparticle reinforced epoxy showed advantage over pure epoxy adhesive (Figs. 4,5). This effect was more pronounced at low deflection rates. The constant displacement rate test was found promising to study microstructural effects in adhesive joints.

Open access