China
Africa
Explore chapters and articles related to this topic
Lighting Quality, Comfort, & Control
Published in Samuel Mills, Fundamentals of ARCHITECTURAL LIGHTING, 2018
Parabolic Reflectors send light rays starting at the focal point of a parabolic shape and reflect them in a direction parallel to the axis of the reflector-producing a light beam of essentially parallel rays useful for spot and flood lighting, especially where a concentrated beam of light with a limited beam spread of light is required.
Luminaires
Published in J. R. Coaton, A. M. Marsden, Lamps and Lighting, 2012
The parabola is the most commonly used reflector contour: it is defined by the equation y2 = 4ax (Figure 18.8), where a is the shortest distance of the focal point to the reflector, i.e. the focal length of the parabola. The most important property of the parabolic reflector is that if a point source is placed at its focus a parallel beam of light is obtained.
P
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
paper tape paper tape strips of paper capable of storing or recording information, most often in the form of punched holes representing the values. Now obsolete. Papoulis' generalization a sampling theory applicable to many cases wherein signal samples are obtained either nonuniformly and/or indirectly. parabolic index profile quadratic transverse variation of the index of refraction; leads to analytic solutions of the paraxial equations for rays and beams. parabolic reflector a reflecting surface defined by a paraboloid of revolution or section of a paraboloid of revolution. paraelectric the nonpolar phase into which the ferroelectric transforms above Tc , frequently called the paraelectric phase. parallel adder a logic circuit that adds two binary numbers by adding pairs of digits starting with the least significant digits. Any carry generated is added with the next pair of digits. The term "parallel" is misleading, since all the digits of each numbers are not added simultaneously. parallel architecture a computer system architecture made up of multiple CPUs. When the number of parallel processors is small, the system is known as a multiprocessing system; when the number of CPUs is large, the system is known as a massively parallel system. parallel bus a data communication path between parts of the system that has one line for each bit of data being transmitted. parallel computing computing performed on computers that have more then one CPU operating simultaneously. parallel computing system a system whose parts are simultaneously running on different processors. parallel data transfer the data transfer proceeds simultaneously over a number of paths, or a bus with a width of multiple bits, so that multiple bits are transferred every cycle. A technique to increase the bandwidth over that of serial data transfer. parallel feed parallel I/O See corporate feed. See parallel input/output.
Energy and exergy analysis of three domestic parabolic solar cookers with different geometries
Published in International Journal of Ambient Energy, 2022
Rajendra Patil, Yogesh Kulkarni, Ankit Gujrathi
Three parabolic solar cookers of the same aperture area with different geometry have been considered for experimental investigation, as shown in Figures 1 and 2. The SK-14 solar cooker has a traditional circular dish, and the focus lies inside the dish due to the deeply curved anodised, polished aluminium parabolic reflector. The fabricated Prince-15 has an innovative parabolic rectangular/square dish. This shape permits the fixing of identical sized anodised aluminium strips as a reflective material on the fabricated structure. On the other hand, the segmented Prince-15 solar cooker has an innovative parabolic metal dish of rectangular/square shape. The innovative shape is constructed in four symmetrical sheet metal sections by cutting paraboloids in parallel planes (Figure 1) and thus making a bowl sturdy. Reflective strips of the same size in the fabricated version were removed due to the segment dish.
Thermal analysis of tilted wick solar distillation-cum-drying system
Published in International Journal of Green Energy, 2019
Himanshu Manchanda, Mahesh Kumar, G.N. Tiwari
The maximum temperature monitored in the drying unit was 58.8°C and 56.1oC, respectively, at a flow rate of 50 and 65 ml/min in the distillation unit (Table 3). ReH in the drying chamber was observed to reduce with an increase in temperature in the drying unit. In the initial hours of the experimentation, the drying chamber temperature was observed relatively low, and surface moisture of the ginger was found to evaporate quickly. After the removal of surface moisture, more energy was required to dry the ginger. The reflected solar radiations from the parabolic reflector provide significant energy to continue the drying process in late hours. Effect of different flow rate in the distillation unit on experimentally evaluated parameters and convective heat transfer coefficients for ginger drying is shown in Table 6.
Design and Analysis of Infrared Heating with Overlapping Heater Array Scheme for Industrial Application
Published in Heat Transfer Engineering, 2018
In this work, the overlapping heater was designed to heat a sheet metal blank for the stamping process in auto industries. The important results are summarized as follows: In the parabolic heater, consisting of a lamp at the focus of a parabolic reflector, the temperature change is generated due to the change of the heat flux directly emitted from the lamps. Minimizing the heat flux change can minimize the temperature change.The principle of the design parameter, Ψ (measure of flux change), is to minimize the change of the heat flux directly from the lamps. Ψ shows that the useful range of the overlapping heater has the distance between lamps ranging from 15 mm to 20 mm.The simulation results show that the overlapping heater drastically reduces the temperature change in the useful range. The simulation results support the usefulness of the design parameter, being in good agreement with the experiment.The experimental results prove that the proposed overlapping heater drastically reduces the temperature change on the heated surface. Consequently, the proposed overlapping heater is usable in the industry.