scholarly journals Prediction of Focal Image for Solar Parabolic Dish Concentrator With Square Facets – An Analytical Model

2021 ◽  
Author(s):  
Arjun Singh Kopalakrishnaswami ◽  
Reyhaneh Loni ◽  
Ghoalmhosein Najafi ◽  
SENDHIL KUMAR NATARAJAN
Keyword(s):  
Electrical Power ◽  
Efficient Design ◽  
Aperture Diameter ◽  
Collector System ◽  
Image Dimension ◽  
Proposed Model ◽  
Parabolic Dish ◽  
Influencing Parameters ◽  
Parabolic Dish Concentrator ◽  
Good Agreement

Abstract Solar parabolic dish concentrator is one of the high-temperature applications of more than 400 °C for thermal and electrical power generation. In the solar parabolic dish concentrator, the arrangement of reflectors over the surface area is the significant factor for effective concentration of solar radiation. Also, focal image is one of the most influencing parameters in the design of receiver. Among the various reflectors, the square shaped reflectors (facets) are comparatively effective in converging the incoming radiations to attain better focal image. In this regard, an attempt has been made to predict the focal image diameter of a solar parabolic dish concentrator with a square facet of different influencing parameters using a novel mathematical model. The influencing parameters considered for the study are aperture diameter, rim angle, and facet length of the dish concentrator. Based on the proposed model, the focal image dimension and aperture area of a solar parabolic dish concentrator with square facets can be predicted accurately for efficient design of a solar parabolic dish collector system. Finally, the proposed model is validated with the experimentally obtained focal image diameter and it is observed that the predicted result is in good agreement with the experimental one. Thus, the proposed model can be effectively used for the design of parabolic dish system for sustainable development.

scholarly journals Implementación de Motor Stirling para generación de energía eléctrica limpia empleando una lente de Fresnel

2019 ◽  
pp. 4-9
Author(s):  
Hilario López-Xelo ◽  
José Juan Hernández-Medina ◽  
Rene Pérez-Martínez ◽  
José Luis Cabrera-Pérez
Keyword(s):  
Energy Demand ◽  
Fossil Fuels ◽  
Electrical Energy ◽  
Fresnel Lens ◽  
Manufacturing Cost ◽  
Toxic Emissions ◽  
Proposed Model ◽  
Parabolic Dish ◽  
Parabolic Dish Concentrator ◽  
Relative Design

In search of expanding the generation of electric power and reduce the burning of fossil fuels. It is proposed to use the tools that already have and the necessary information to make a prototype of Alfa type Stirling engine, which is a thermal machine with low levels of noise and toxic emissions, that its relative design is of low manufacturing cost for the generation of clean electrical energy, for the heating we will use a Fresnel lens with the purpose of satisfying the thermal energy demand of the same, in the sense of achieving the best angle of capture of solar rays, at the same time achieving the highest concentration of heat possible for the heating angle of the motor. The validation of the proposed model is based on experimental results, using the information obtained from the production of electrical energy, with this the validation of the prototype will be performed, similar to the solar parabolic dish concentrator.

scholarly journals Compact Modelling of Electrical, Optical and Thermal Properties of Multi-Colour Power LEDs Operating on a Common PCB

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1286
Author(s):  
Krzysztof Górecki ◽  
Przemysław Ptak
Keyword(s):  
Integrated Circuits ◽  
Optical Model ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Junction Temperature ◽  
Optical Parameters ◽  
Spice Simulation ◽  
Light Emitting ◽  
Proposed Model ◽  
Good Agreement

This paper concerns the problem of modelling electrical, thermal and optical properties of multi-colour power light-emitting diodes (LEDs) situated on a common PCB (Printed Circuit Board). A new form of electro-thermo-optical model of such power LEDs is proposed in the form of a subcircuit for SPICE (Simulation Program with Integrated Circuits Emphasis). With the use of this model, the currents and voltages of the considered devices, their junction temperature and selected radiometric parameters can be calculated, taking into account self-heating phenomena in each LED and mutual thermal couplings between each pair of the considered devices. The form of the formulated model is described, and a manner of parameter estimation is also proposed. The correctness and usefulness of the proposed model are verified experimentally for six power LEDs emitting light of different colours and mounted on an experimental PCB prepared by the producer of the investigated devices. Verification was performed for the investigated diodes operating alone and together. Good agreement between the results of measurements and computations was obtained. It was also proved that the main thermal and optical parameters of the investigated LEDs depend on a dominant wavelength of the emitted light.

Static and Dynamic Structure of Molecular Monomers and Dimers of the Rare-earth Fluorides

2001 ◽  
Vol 56 (5) ◽  
pp. 381-385
Author(s):  
Z. Akdeniz ◽  
M . Gaune-Escard ◽  
M. P. Tosi
Keyword(s):  
Rare Earth ◽  
Bond Length ◽  
Geometrical Structure ◽  
Vibrational Mode ◽  
Dynamic Structure ◽  
Molecular Shape ◽  
Proposed Model ◽  
Infrared Studies ◽  
Charged Clusters ◽  
Good Agreement

Abstract We determine a model of the ionic interactions in RF3 compounds, where R is a rare-earth element in the series from La to Lu, by an analysis of data on the bond length and the vibrational mode frequencies of the PrF3, GdF3 and HoF3 molecular monomers. All RF3 monomers are predicted to have a pyramidal shape, displaying a progressive flattening of the molecular shape in parallel with the lanthanide contraction of the bond length. The vibrational frequencies of all monomers are calculated, the results being in good agreement with the data from infrared studies of matrix-isolated molecules. We also evaluate the geometrical structure and the vibrational spectrum of the La2F6 and Ce2F6 dimers, as a further test of the proposed model. -PACS 36.40.Wa (Charged clusters)

Reloading Stress Relaxation Behavior Analysis Based on a Creep Model for High Temperature Bolting Steel

2013 ◽  
Vol 328 ◽  
pp. 950-954
Author(s):  
Wei Wei Zhang ◽  
Hong Xu ◽  
Hong Yuan Li
Keyword(s):  
High Temperature ◽  
Stress Relaxation ◽  
Steady State Creep ◽  
Relaxation Behavior ◽  
Creep Model ◽  
National Research Institute ◽  
Time Intervals ◽  
Stress Relaxation Behavior ◽  
Proposed Model ◽  
Good Agreement

An analytical method based on a creep model is being developed to investigate the effect of retightening on stress relaxation behavior for high-temperature turbine and valve studs/bolts. In order to validate the approach, the calculated results are compared to the results of uniaxial reloading stress relaxation testing, which were performed by the National Research Institute for Metals of Japan (NRIM) for 12Cr-1Mo-1W-1/4V stainless steel bolting material at 550°C. It was shown that the proposed model based on Altenbach-Gorash-Naumenko creep model for the primary and steady state creep could be applied for the present data. The calculated residual stresses versus time curves were in good agreement with the measured for initial stress level of 273.6MPa at 550°C and for specific reloading time intervals of 24, 72, 240, and 720 hours.

PZT ceramic particles/polyurethane composites formalism for mechanical energy harvesting

2020 ◽  
Vol 89 (3) ◽  
pp. 30901 ◽  
Author(s):  
Abdelkader Rjafallah ◽  
Abdelowahed Hajjaji ◽  
Fouad Belhora ◽  
Abdessamad El Ballouti ◽  
Samira Touhtouh ◽  
...  
Keyword(s):  
Polymer Composites ◽  
Electromechanical Coupling ◽  
Piezoelectric Coefficient ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Ferroelectric Ceramic ◽  
Ferroelectric Ceramics ◽  
High Compliance ◽  
Polyurethane Composites ◽  
Good Agreement

More recently, the ferroelectric ceramic/polymer composites have been progressively replacing ferroelectric ceramics and polymers as they combine their interesting properties. Such as high compliance of polymers and high electromechanical coupling of ferroelectric ceramics those are required for piezoelectric transducer applications. At the same time, the ferroelectric ceramic/polymer composites formalism for predicting their energy-conversion capabilities is of both academic and industrial interest. The novelty of this paper is that the electrical power harvested by the PZT/PU polarized composite has been expressed in terms of the effective longitudinal piezoelectric coefficient (d33) of the composite via a parameter p related to the poling ratio. Besides, the parameter p, that is characterizing the PZT/PU composites with different longitudinal piezoelectric coefficients (d33), was evaluated. The other parameters of the electrical power expression were calculated using the Yamada model for the dielectric, piezoelectric and elastic constants. Finally, a good agreement was found between experience and model.

scholarly journals Compact Model for Bipolar and Multilevel Resistive Switching in Metal-Oxide Memristors

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 98
Author(s):  
Eugeny Ryndin ◽  
Natalia Andreeva ◽  
Victor Luchinin
Keyword(s):  
Metal Oxide ◽  
Equation System ◽  
Software Implementation ◽  
Compact Model ◽  
Metal Oxide Films ◽  
Bipolar Switching ◽  
Proposed Model ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Good Agreement

The article presents the results of the development and study of a combined circuitry (compact) model of thin metal oxide films based memristive elements, which makes it possible to simulate both bipolar switching processes and multilevel tuning of the memristor conductivity taking into account the statistical variability of parameters for both device-to-device and cycle-to-cycle switching. The equivalent circuit of the memristive element and the equation system of the proposed model are considered. The software implementation of the model in the MATLAB has been made. The results of modeling static current-voltage characteristics and transient processes during bipolar switching and multilevel turning of the conductivity of memristive elements are obtained. A good agreement between the simulation results and the measured current-voltage characteristics of memristors based on TiOx films (30 nm) and bilayer TiO2/Al2O3 structures (60 nm/5 nm) is demonstrated.

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