Growth and characterization of heteroepitaxial La-substituted BaSnO3_3 films on SrTiO3_3 (001) and SmScO3_3 (110) substrates

Heteroepitaxial growth of BaSnO$_3$ (BSO) and Ba$_{1-x}$La$_x$SnO$_3$ (x = 7 %) (LBSO) thin films on different perovskite single crystal (SrTiO$_3$ (001) and SmScO$_3$ (110)) substrates has been achieved by Pulsed Laser Deposition (PLD) under optimized deposition conditions. X-ray diffraction measurements indicate that the films on either of these substrates are relaxed due to the large mismatch and present a high degree of crystallinity with narrow rocking curves and smooth surface morphology while analytical quantification by proton induced x-ray emission (PIXE) confirms the stoichiometric La transfer from a polyphasic target, producing films with La contents above the bulk solubility limit. The films show degenerate semiconducting behavior on both substrates, with the observed room temperature resistivities, Hall mobilities and carrier concentrations of 4.4 $m \Omega cm$, 10.11 $cm^2 V^{-1} s^{-1}$, and 1.38 $\cdot 10^{20} cm^{-3}$ on SmScO$_3$ and 7.8 $m \Omega cm$, 5.8 $cm^2 V^{-1} s^{-1}$, and 1.36 $\cdot 10^{20} cm^{-3}$ on SrTiO$_3$ ruling out any extrinsic contribution from the substrate. The superior electrical properties observed on the SmScO3 substrate are attributed to reduction in dislocation density from the lower lattice mismatch.Comment: 11 pages, 3 figures, supplementary informations 2 figure

Smart Solar System With Digitizer

In the past these where working on pure AC supply. The components used in these types of appliances were also AC. The limitation of AC supply was that it required more current then we used our project for example. LED scrolling display used 230Volt/35Amp (AC) before, whereas our project uses 5Volt/10Amp (DC).Now we are using solar power for working of these appliances. We are combining all three appliances on one source. It provides combined features where we can display the notice, streets can get light and there is facility to charge phone in emergency.In future we can add a network router to this combination. This will give free internet connection to rural areas with effective 500m working diameter. The display can be modifyingsuch a way that it receives order from voice messages

Study on Behavior on High Strength Crimped Steel Fibre Reinforced Concretefor Grade M90

The use of High Strength Concrete (HSC) is on rise. HSC is very strong in compression but it is relatively brittle material and week in tension. Crimped steel Fibres are added to improve its ductility by bridging internal cracks. Experimental study is carried out to assessment of mechanical properties of high strength fibre reinforced concrete (HSFRC) for M90 grade.High strength concrete (HSC) is made with appropriate cementitiousmaterials i.e. cement fly ash and silicaby DOE mix design method. The fibre volume fraction is used 0 to 4 % at 0.5% interval. Total 54 memberswere casted and tested for cube (100 X 100 X 100) mm and cylinder (150 X 300) mm each. Total members cured for 7 and 28 days in curing tank of civil engineering concrete technology laboratory

A Review of Heat Transfer Enhancement Using Twisted Tape with and Without Perforation

Energy conservation and beneficial from economic point of view heat transfer enhancement is important factor. There are many techniques to enhance the heat transfer rate through, Passive and active techniques. Passive techniques like, twisted tapes, wire inserts and roughness of element ismost effective methods for heat transfer enhancement. Many studies have been carried out on different geometries of twisted tapes to increase the rate of heat transfer. Several correlations have been developed between heat transfer and friction factor for inserts of twisted tapes. In current study, a literature review of heat transfer enhancement in heat exchanger using twisted tapes has been done. Experimental and numerical studies on various twisted tapes with and without perforation arediscussed based on the literature.The development in heat exchanger systems will be improvedis shown in this studies. The research area in heat exchanger for enhancement in heat transfer rate is so big. Twisted tape optimum shape can also be developed based on the minimum friction factorand maximum heat transfer in flui

Numerical analysis of non-isothermal Newtonian flows in plate heat exchangers

Associar ao Dep. de Tecnologia Química e Biológica - docente Ricardo DiasNumerical analysis of non-isothermal Newtonian flows in plate heat exchanger passages is carried out in the laminar flow region. The results of this analysis are compared with information available in the literature. Some interesting trends are observed for both heat transfer and pressure drop with varying chevron angle. Areas of further work are delineated and it is emphasised that practical ranges of inter-plate distance, corrugation pitch and the development ratio need to be studied to fully understand the practical implications of the current numerical work

Evolution of nanoripples on silicon by gas cluster-ion irradiation

Si wafers of (100), (110) and (111) orientations were bombarded by gas cluster ion beam (GCIB) of 3000 Ar-atoms/cluster on average at a series of angles. Similar surface morphology ripples developed in different nanoscales. A simple scaling functional satisfactorily describe the roughness and wavelength of the ripple patterns as a function of dosage and angle of incidence. The ripples are formed orthogonal to the incident cluster-ions at large off-normal angles. An ellipsoidal pattern was created by two consecutive irradiations incident in mutually orthogonal directions with unequal exposure times between each irradiation, from 7:1 to 10:1, beyond which the original ripple imprints would be over-written. This work was inspired by use of the ripples to seed growth of controlled nanostructures without patterning by lithography or predeposition of catalysts