The Effect of Solar Tracking Resolution to the Defocus of a Giant Fresnel Lens for a Solar Stove

2012 ◽  
Author(s):  
Peter Kane ◽  
Matthew Mokler ◽  
Peiwen Li ◽  
Ricardo G. Sanfelice
Keyword(s):  
Control System ◽  
Passive Control ◽  
Thermal Protection ◽  
Focal Point ◽  
Fresnel Lens ◽  
System Control ◽  
Solar Tracking ◽  
University Of Arizona ◽  
The University ◽  
Control Accuracy

A solar stove using a giant Fresnel lens has been developed in the Energy and Fuel Cell Laboratory at the University of Arizona. Solar tracking is required to control the Fresnel lens to maintain a stationary focal point on the heat transfer surface of the solar stove. A two-axis passive control system for solar tracking is adopted. Characteristics of the optical system are analyzed in order to find a reasonable tracking and adjustment frequency and overall system control accuracy. Defocus of the lens due to the angular offset (related to tracking resolution) of the lens’ axis versus the sunray and the change of the shape of the focal point on a static plate is calculated. The results of the analysis are used in the design of the control algorithm which has been implemented in the control system of the prototype solar stove. The proposed tracking scheme is expected to improve heat collection, thermal protection and thereby reduction of heat loss in the solar stove.

Image and Ray Tracing Analysis of a Parabolic Dish Collector to Achieve High Flux on a Solar Volumetric Reactor

MRS Advances ◽  
2020 ◽  
Vol 5 (50) ◽  
pp. 2545-2553
Author(s):  
Nidia Aracely Cisneros-Cárdenas ◽  
Rafael Enrique Cabanillas-López ◽  
Ramiro Alberto Calleja-Valdez ◽  
Ricardo Arturo Pérez-Enciso ◽  
Carlos Alberto Pérez-Rábago ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Ray Tracing ◽  
Focal Point ◽  
Operating Conditions ◽  
Normal Operating ◽  
University Of Arizona ◽  
Parabolic Dish ◽  
Parabolic Dish Concentrator ◽  
The University ◽  
Ray Tracing Simulation

ABSTRACTThe need to achieve a uniform distribution of concentrated solar flux in the photovoltaic, thermal or any other receivers is a common problem; therefore, the optical characterization of the concentration system is necessary to determinate the physical characteristics of the receptors. In this work, a parabolic dish concentrator of 1.65x1.65 m2, developed by research from the University of Arizona, is optically characterized under normal operating conditions, also known as environmental conditions that refer to non-controlled conditions as solar radiation, environmental temperature and wind velocity that could affect slightly, by thermal and mechanical efforts, the distribution profiles of the concentrated solar radiation. The set used for the evaluation consisted of the parabolic mirror and Chilled Lambertian Flat Surface installed in the focal point on the optical axis of the mirror. The evaluation was divided into two parts: a theoretical part that consist on using ray tracing simulation and an experimental part that corresponds to image analysis. The used methodology in this work has been stablish in many researches, so this is a reliable method. The global optical error was 2.3 mrad under normal operating conditions.

Electrostatic optics and aberration correction in the 1940s and today

1992 ◽  
Vol 50 (1) ◽  
pp. 6-7
Author(s):  
Gertrude F. Rempfer
Keyword(s):  
Electron Microscope ◽  
Focal Point ◽  
Focal Length ◽  
High Vacuum ◽  
Electron Optics ◽  
Applied Physics ◽  
Electrostatic Lenses ◽  
Commercial Instrument ◽  
The University ◽  
Theory And Experiment

I became involved in electron optics in early 1945, when my husband Robert and I were hired by the Farrand Optical Company. My husband had a mathematics Ph.D.; my degree was in physics. My main responsibilities were connected with the development of an electrostatic electron microscope. Fortunately, my thesis research on thermionic and field emission, in the late 1930s under the direction of Professor Joseph E. Henderson at the University of Washington, provided a foundation for dealing with electron beams, high vacuum, and high voltage.At the Farrand Company my co-workers and I used an electron-optical bench to carry out an extensive series of tests on three-electrode electrostatic lenses, as a function of geometrical and voltage parameters. Our studies enabled us to select optimum designs for the lenses in the electron microscope. We early on discovered that, in general, electron lenses are not “thin” lenses, and that aberrations of focal point and aberrations of focal length are not the same. I found electron optics to be an intriguing blend of theory and experiment. A laboratory version of the electron microscope was built and tested, and a report was given at the December 1947 EMSA meeting. The micrograph in fig. 1 is one of several which were presented at the meeting. This micrograph also appeared on the cover of the January 1949 issue of Journal of Applied Physics. These were exciting times in electron microscopy; it seemed that almost everything that happened was new. Our opportunities to publish were limited to patents because Mr. Farrand envisaged a commercial instrument. Regrettably, a commercial version of our laboratory microscope was not produced.

DESIGN, SIMULATION AND IMPLEMENTATION MONITORING SYSTEM FOR SYSTEM CONTROL C4 FEEDING PUMP FOR FEED VAPORIZATION IN THE BUTADIENE PLANT

2020 ◽  
Vol 1 (1) ◽  
pp. 31-35
Author(s):  
Fahmi Yunistyawan ◽  
Yunistyawan J Berchmans ◽  
Gembong Baskoro
Keyword(s):  
Motor Control ◽  
Control System ◽  
Field Operator ◽  
System Control ◽  
Variable Speed ◽  
Variable Speed Drive ◽  
Software And Hardware ◽  
Discharge Pressure ◽  
Selection Of

This study implements the auto start control system on an electric motor 3 phase C4Feeding pump when the discharge pressure is low-low (4.3 kg /cm²). The C4 feeding pumpmotor was initially manually operated from the local control station, this was very ineffectiveand inefficient because it still relied on the field operator to operate the pump motor and whenthe plant was in normal operating it is very risk if the field operator late to operate motor then itwill impact to quality of the product, and if the delay time to operate motor is too long then planthave to shut down, therefore improvement is needed in the C4 feeding pump motor controlsystem. In this paper, various types of 3-phase motor control are explained which allow it to beapplied to the C4 feeding pump motor that are on-off, inverter, and variable speed drive andefficient selection of the three systems control of the motor. Software and hardware used in thisthesis work are DCS CENTUM VP Yokogawa.

RADIOCARBON IN MEXICO: FROM PROPORTIONAL COUNTERS TO AMS

Radiocarbon ◽  
2021 ◽  
pp. 1-7
Author(s):  
Corina Solís ◽  
Efraín Chávez ◽  
Arcadio Huerta ◽  
María Esther Ortiz ◽  
Alberto Alcántara ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Sample Preparation ◽  
High Voltage ◽  
Accelerator Mass Spectrometry ◽  
Science And Technology ◽  
National Council ◽  
University Of Arizona ◽  
Technological Developments ◽  
High Voltage Engineering ◽  
The University

ABSTRACT Augusto Moreno is credited with establishing the first radiocarbon (14C) laboratory in Mexico in the 1950s, however, 14C measurement with the accelerator mass spectrometry (AMS) technique was not achieved in our country until 2003. Douglas Donahue from the University of Arizona, a pioneer in using AMS for 14C dating, participated in that experiment; then, the idea of establishing a 14C AMS laboratory evolved into a feasible project. This was finally reached in 2013, thanks to the technological developments in AMS and sample preparation with automated equipment, and the backing and support of the National Autonomous University of Mexico and the National Council for Science and Technology. The Mexican AMS Laboratory, LEMA, with a compact 1 MV system from High Voltage Engineering Europa, and its sample preparation laboratories with IonPlus automated graphitization equipment, is now a reality.

The Design of Control System of Rapid Prototyping Machine for Ceramic Parts Based on SIEMENS S7-200

2011 ◽  
Vol 291-294 ◽  
pp. 2898-2905
Author(s):  
Dong Qiang Gao ◽  
Fei Zhang ◽  
Zhi Yun Mao ◽  
Zhong Yan Li
Keyword(s):  
Control System ◽  
Rapid Prototyping ◽  
Control Method ◽  
Comprehensive Performance ◽  
Control Accuracy

The traditional control system of rapid protyping machine for ceramic parts has many shortcomings: complex wiring, low control accuracy, incovenience maintenance and lack of flexibility, while the control method based on PLC can improve the comprehensive performance of the overall machine. The paper selectsSIEMENS S7-200 small PLC system to do generalized design for the rapid protyping machine for ceramic: including the wiring conection of hardware and distribution of I/O; programming by V4.0 STEP7-Micro/WIN SP3 software,which is flexible, interface friendly and debugging convienent.

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