scholarly journals Adapting Active Reflector Technology for greater sensitivity and sky-coverage in FAST-like Telescopes

2020 ◽  
Author(s):  
Jian-Ling Li ◽  
Bo Peng ◽  
Cheng-Jin Jin ◽  
Hui Li ◽  
Richard G Strom ◽  
...  
Keyword(s):  
Radio Telescope ◽  
Zenith Angle ◽  
Spherical Surface ◽  
Innovative Technology ◽  
Spherical Surfaces ◽  
The World ◽  
Active Reflector

Abstract The Five-hundred-meter Aperture Spherical radio Telescope (FAST), the largest single dish radio telescope in the world, has implemented an innovative technology for its huge reflector, which changes the shape of the primary reflector from spherical to that of a paraboloid of 300 m aperture. Here we explore how the current FAST sensitivity can potentially be further improved by increasing the illuminated area (i.e., the aperture of the paraboloid embedded in the spherical surface). Alternatively, the maximum zenith angle can be increased to give greater sky coverage by decreasing the illuminated aperture.Different parabolic apertures within the FAST capability are analyzed in terms of how far the spherical surface would have to move to approximate a paraboloid. The sensitivity of FAST can be improved by approximately 10% if the aperture of the paraboloid is increased from 300 m to 315 m. The parabolic aperture lies within the main spherical surface and does not extend beyond its edge. The maximum zenith angle can be increased to approximately 35 degrees from 26.4 degrees, if we decrease the aperture of the paraboloid to 220 m. This would still give a sensitivity similar to the Arecibo 305 m radio telescope. Radial deviations between paraboloids of different apertures and the spherical surfaces of differing radii are also investigated. Maximum zenith angles corresponding to different apertures of the paraboloid are further derived. A spherical surface with a different radius can provide a reference baseline for shape-changing applied through active reflector technology to FAST-like telescopes.

scholarly journals Realization of a Service Robot for Cleaning Spherical Surfaces

10.5772/5800 ◽  
2005 ◽  
Vol 2 (1) ◽  
pp. 7 ◽  
Author(s):  
Houxiang Zhang ◽  
Jianwei Zhang ◽  
Rong Liu ◽  
Guanghua Zong
Keyword(s):  
Control System ◽  
Spherical Surface ◽  
Service Robot ◽  
Climbing Robot ◽  
Complicated Shape ◽  
Ability To Work ◽  
Distributed Controller ◽  
Spherical Surfaces ◽  
The World ◽  
Remote Controller

There are more and more buildings with complicated shape emerging all over the world. Their walls require constant cleaning which is difficult to realize. In this paper, based on analyzing the characteristics of the working target, a new kind of auto-climbing robot is proposed, which is used for cleaning the spherical surface of the National GrandTheatre in China. The robots' mechanism and unique aspects are presented in detail. A distributed controller based onCAN bus is designed to meet the requirements of controlling the robot. The control system is divided into 6 parts, fiveCAN bus control nodes and a remote controller, which are designed and established based mainly on the P80C592. Finally, the motion function is described in detail. The experimental results confirm the principle described above andthe robot's ability to work on the spherical surface.

Testing the link between mergers and AGN in the Arp 245 system

2020 ◽  
Vol 15 (S359) ◽  
pp. 192-194
Author(s):  
Elismar Lösch ◽  
Daniel Ruschel-Dutra
Keyword(s):  
Star Formation ◽  
Active Galactic Nucleus ◽  
Spherical Surface ◽  
Galaxy Mergers ◽  
Nuclear Activity ◽  
Upper Limit ◽  
Spherical Surfaces ◽  
Galactic Centers ◽  
Merger Event ◽  
Major Merger

AbstractGalaxy mergers are known to drive an inflow of gas towards galactic centers, potentia- lly leading to both star formation and nuclear activity. In this work we aim to study how a major merger event in the ARP 245 system is linked with the triggering of an active galactic nucleus (AGN) in the NGC galaxy 2992. We employed three galaxy collision numerical simulations and calculated the inflow of gas through four different concentric spherical surfaces around the galactic centers, estimating an upper limit for the luminosity of an AGN being fed the amount of gas crossing the innermost spherical surface. We found that these simulations predict reasonable gas inflow rates when compared with the observed AGN luminosity in NGC 2992.

Research on Transition Zones of Spherical Surface Parts in 3D Rolling Process

2014 ◽  
Vol 687-691 ◽  
pp. 3-6
Author(s):  
Da Ming Wang ◽  
Ming Zhe Li ◽  
Zhong Yi Cai
Keyword(s):  
Sheet Metal ◽  
Spherical Surface ◽  
Three Dimensional ◽  
Rolling Process ◽  
Experimental Results ◽  
Transition Zones ◽  
Spherical Surfaces ◽  
Sheet Width ◽  
Forming Precision ◽  
Roll Gap

3D rolling is a novel technology for three-dimensional surface parts. In this process, by controlling the gap between the upper and lower forming rolls, the sheet metal is non-uniformly thinned in thickness direction, and the longitudinal elongation of the sheet metal is different along the transverse direction, which makes the sheet metal generate three-dimensional deformation. In this paper, the transition zones of spherical surface parts in 3D rolling process are investigated. Spherical surface parts with the same widths but different lengths are simulated in condition of the same roll gap, and their experimental results are presented. The forming precision of forming parts and the causes of transition zones in the head and tail regions are analyzed through simulated results. The simulated and experimental results show that the lengths of transition zones of spherical surfaces in the head and tail regions are fixed values in condition of the same sheet width and roll gap.

scholarly journals The Method of Cluster Drilling in the Western Ural as the Beginning of the Technical and Economic Revolution in the World Drilling

TECHNOLOGOS ◽  
2020 ◽  
pp. 47-57
Author(s):  
Neroslov Alexey
Keyword(s):  
Large Scale ◽  
High Efficiency ◽  
Oil Industry ◽  
Advanced Technology ◽  
Innovative Technology ◽  
Drilling Process ◽  
Directional Drilling ◽  
North Caucasus ◽  
The World ◽  
The City

In 1943, at the height of the Great Patriotic War, the new revolutionary drilling technique with high efficiency was used in Krasnokamsk oilfield of Molotov (Perm) Oblast for the first time in the world – the cluster turbodrilling method. The development of oil industry in Prikamye in the 1940s was associated with certain complications. The main deposits of the Krasnokasmk oilfield discovered before the war turned out to be located due to a number of reasons within the area of industrial and residential construction of the city of Krasnokamsk and under the Kama river and the Paltinskoye swamp close to the city. Conventional drilling methods could not be used for their development. The way out was to use the method of directional drilling that was little known at that moment. The development of the innovative technology in Krasnokamsk oilfield in 1942 was largely due to the involvement of the specialists of the Experimental Turbodrilling Bureau evacuated from Baku. Directional drilling which involved the deviation of the bottom hole (the ultimate lowest point of the well) from the wellhead (the initial uppermost location) by several hundred metres opened up broad opportunities for developing hard-to-recover oil deposits while significantly accelerating and ensuring cost savings of the drilling process. The directional drilling served as the basis for the development in Prikamye of an advanced technology of cluster drilling when several directional wells with different azimuths were drilled from a small well pad. In 1943–1944, cluster drilling was tested and successfully used in Krasnokamsk oilfield. The cluster drilling comprised an entire range of innovative solutions including the movement of assembled drilling rigs without dismantling power equipment. Also, it resulted in the reduction of total labour costs, scope of construction and assembly works, costs of building oilfield roads, power lines and pipelines, and transportation costs. People’s Commissariat of Oil Industry of the USSR initiated a large-scale rollout of the advanced method of cluster drilling in the largest oil-producing regions of the Soviet Union – Azerbaijan and the North Caucasus, and the area of the “second Baku” – Bashkiria, Tatary, and Kuybyshev oblast. The transition to the advanced and cost-saving technology of cluster drilling laid the foundation for the technical and economic revolution of the world drilling practices.

Study of The Tool Path Generation Method of an Ultra-Precision Spherical Complex Surface Based on a Five-Axis Machine Tool

2021 ◽  
Author(s):  
Tianji Xing ◽  
Xuesen Zhao ◽  
Zhipeng Cui ◽  
Rongkai Tan ◽  
Tao Sun
Keyword(s):  
Surface Roughness ◽  
Tool Path ◽  
Spherical Surface ◽  
Tool Path Generation ◽  
Path Generation ◽  
Tool Paths ◽  
Spherical Surfaces ◽  
Spherical Complex ◽  
Ultra Precision ◽  
Five Axis

Abstract The improvement of ultra-precision machining technology has significantly boosted the demand for the surface quality and surface accuracy of the workpieces to be machined. However, the geometric shapes of workpiece surfaces cannot be adequately manufactured with simple plane, cylindrical, or spherical surfaces because of their different applications in various fields. In this research, a method was proposed to generate tool paths for the machining of complex spherical surfaces based on an ultra-precise five-axis turning and milling machine with a C-Y-Z-X-B structure. Through the proposed tool path generation method, ultra-precise complex spherical surface machining was achieved. First, the complex spherical surface model was modeled and calculated, and then it was combined with the designed model to generate the tool path. Then the tool paths were generated with a numerically controlled (NC) program. Based on an ultra-precision three-coordinate measuring instrument and a white light interferometer, the machining accuracy of a workpiece surface was characterized, and t[1]he effectiveness of the provided tool path generation method was verified. The surface roughness of the machined workpiece was less than 90 nm. Furthermore, the surface roughness within the spherical region appeared to be less than 30 nm. The presented tool path generation method in this research produced ultra-precision spherical complex surfaces. The method could be applied to complex spherical surfaces with other characteristics.

Influence of Socio-Economy in the Next Generation of Thermal Management Solutions for Electronics Consumer Products

2008 ◽  
Author(s):  
Gamal Refai-Ahmed
Keyword(s):  
High Performance ◽  
Heat Dissipation ◽  
Raw Materials ◽  
Cost Effective ◽  
Electronics Packaging ◽  
Consumer Products ◽  
Innovative Technology ◽  
Target Market ◽  
The World ◽  
The Impact

The past few decades have seen a number of countries around the world emerge as a growing market for high performance computers. This present study examines, in more detail, how socio-economic influences are shaping the demand function and how some computing landscapes are changing as a consequence. This study is addressing one of the key initiatives to enable 50 percent of the world’s population with access to the World Wide Web. Furthermore, this investigation is addressing the challenges for electronics packaging Engineers and Researchers. Therefore, the rational of the developed technology based on the understanding target market and usages will be given. The impact of addressing the heat dissipation and managing the use of the raw materials of the intended products are discussed. In addition, how the electronics packaging engineers can focus on developing affordable innovative technology. Finally, the impact of all of the above is examined in developing the cost effective solution from a global point of view.

scholarly journals Extending the Observable Zenith Angle of FAST Using an Offset Feed

2001 ◽  
Vol 182 ◽  
pp. 255-259
Author(s):  
Li Guoding ◽  
R. Nan ◽  
B. Peng
Keyword(s):  
Real Time ◽  
Active Control ◽  
Radio Telescope ◽  
Zenith Angle ◽  
Spherical Reflector ◽  
Paraboloid Of Revolution ◽  
Reflecting Surface

AbstractThe five hundred meter aperture spherical radio telescope is will use an active spherical reflector. When the zenith scan angle is changed, the illuminated part of the reflecting surface is made to fit a paraboloid of revolution in real time by active control. The maximum zenith scan angle | ψmax | of FAST is 30° under conditions of the geometry selected in order that the feed does not illuminate the ground. The result of this paper shows that the maximum zenith scan angle | ψmax | can be extended to 69° by offsetting the feed.

Fundamental Study on Diamond Spherical Shell Film for Polishing of Concave Spherical Surface

2008 ◽  
Vol 375-376 ◽  
pp. 380-384
Author(s):  
Duo Sheng Li ◽  
Dun Wen Zuo ◽  
Rong Fa Chen ◽  
Yu Li Sun ◽  
Bing Kun Xiang ◽  
...  
Keyword(s):  
Spherical Shell ◽  
Spherical Surface ◽  
High Surface ◽  
Chemical Vapor ◽  
High Hardness ◽  
Internal Quality ◽  
Curvature Radius ◽  
Fundamental Study ◽  
Force Microscopy ◽  
Spherical Surfaces

In this paper, a new polishing technique was proposed to polish concave spherical surface by diamond spherical shell deposited by DC-Plasma Jet CVD(chemical vapor deposition), and preparation was studied from both experiment and theory. The deposited films were investigated by some techniques including: scanning electron microscopy (SEM), atom force microscopy (AFM), Raman spectroscopy, and roughness-profile-meter, which were used to analyze surface phase, microstructure, internal quality and surface roughness. The results show that the deposited diamond spherical shell film has some remarkable properties, such as high surface density, high hardness. Compared to traditional polishing techniques, it will have some potential advantages as convenient, flexible, efficient and precious. To adjust some important parameters as methane concentration, depositing time, and it can deposit the different size grain diamond spherical shell films, which are used to polish different precision degree concave spherical surfaces. Meantime, to change curvature of diamond spherical shell, it can adapt to polish various curvature radius concave spherical surfaces.

scholarly journals Expectations of maser studies with FAST

2012 ◽  
Vol 8 (S287) ◽  
pp. 350-353 ◽  
Author(s):  
Jiang Shui Zhang ◽  
Di Li ◽  
Jun Zhi Wang
Keyword(s):  
Radio Telescope ◽  
The World

AbstractThe Five-hundred-meter Aperture Spherical radio Telescope (FAST) is being built by the Chinese and will be the largest single dish radio telescope in the world. FAST, with much increase in sensitivity, will give astronomers good opportunities to answer many fundamental questions in astronomy. Here we give a brief introduction of FAST and its enormous potential for studying Galactic and extragalactic masers.

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