Sensitive Analysis for the Efficiency of a Parabolic Trough Solar Collector Based on Orthogonal Experiment

A multitude of the researches focus on the factors of the thermal efficiency of a parabolic trough solar collector, that is, the optical-thermal efficiency. However, it is limited to a single or double factors for available system. The aim of this paper is to investigate the multifactors effect on the system’s efficiency in cold climate region. Taking climatic performance into account, an average outlet temperature of LS-2 collector has been simulated successfully by coupling SolTrace software with CFD software. Effects of different factors on instantaneous efficiency have been determined by orthogonal experiment and single factor experiment. After that, the influence degree of different factors on the collector instantaneous efficiency is obtained clearly. The results show that the order of effect extent for average maximal deviation of each factor is inlet temperature, solar radiation intensity, diameter, flow rate, condensation area, pipe length, and ambient temperature. The encouraging results will provide a reference for the exploitation and utilization of parabolic trough solar collector in cold climate region

Modifying Photos Based on Photo Capture from Multiple Device Cameras

This disclosure describes techniques to modify photos based on additional photos captured from multiple cameras of a device. A user captures a main photo of a scene with one camera of a device, and, in the background, additional photo(s) are automatically captured by other camera(s) of the device. Portions from the additional photos can be used to modify the main photo. For example, the view and/or aspect ratio of the captured photo can be modified to show portions of the scene that are not present in the main photo. This saves the user time and effort by automatically capturing additional photos of a scene and providing a range of editing options that take advantage of the additional photos

Preparation and electromechanical properties of PVDF matrix piezo-electric composites containing highly oriented BaTiO3 whiskers

The piezoelectric composites containing highly oriented BaTiO3 whiskers as active phase and PVDF as matrix have been prepared by micro-hole extrusion and orientation in carried fibers. The morphology of oriented BaTiO3 whiskers and microstructure of the composites were observed by SEM. As for its electromechanical properties, it is found that the dielectric constant, piezoelectric constant and remnant of polarization in the BaTiO3 whisker-PVDF composite are considerably higher than that in the BaTiO3 powders-PVDF composite, while the loss factors follow the opposite trend. For the BaTiO3 whisker-PVDF composite, the values of epsilon, d(33) and P-r parallel to the whisker orientation (normal specimen) are much higher than that perpendicular to the whisker orientation (parallel specimen). The significant effects of the connective passages of active phase on electromechanical properties of the piezoelectric composites has also been investigated