Impact Point of Probing Rockets by Telemetry and Slant Range

2021 ◽  
Author(s):  
Nilton Rodrigues Cantanhede ◽  
Ewaldo Eder Carvalho Santana ◽  
Paulo Fernandes da Silva Junior ◽  
Jonas de Jesus Barros ◽  
Raimundo Carlos Silverio Freire
Keyword(s):  
Impact Point ◽  
Slant Range

High Resolution Scanning Electron Microscopy

1991 ◽  
Vol 49 ◽  
pp. 478-479
Author(s):  
David Joy ◽  
James Pawley
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Beam ◽  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Electron Probe ◽  
Impact Point ◽  
Interaction Volume ◽  
Scanning Electron

The scanning electron microscope (SEM) builds up an image by sampling contiguous sub-volumes near the surface of the specimen. A fine electron beam selectively excites each sub-volume and then the intensity of some resulting signal is measured. The spatial resolution of images made using such a process is limited by at least three factors. Two of these determine the size of the interaction volume: the size of the electron probe and the extent to which detectable signal is excited from locations remote from the beam impact point. A third limitation emerges from the fact that the probing beam is composed of a finite number of discrete particles and therefore that the accuracy with which any detectable signal can be measured is limited by Poisson statistics applied to this number (or to the number of events actually detected if this is smaller).

Analysis of Effective Slant Range Model Accuracy Based on Low-Earth-Orbital (LEO) Spaceborne SAR

2014 ◽  
Vol 35 (1) ◽  
pp. 56-62
Author(s):  
Bing-ji Zhao ◽  
Xiang-yang Qi ◽  
Hong-jun Song ◽  
Hui Zhou
Keyword(s):  
Model Accuracy ◽  
Slant Range

scholarly journals Influence of the Submerged Entry Nozzle’s Bottom Well on the Characteristics of Its Exit Jets

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 398
Author(s):  
Jesus Gonzalez-Trejo ◽  
Cesar A. Real-Ramirez ◽  
Jose Raul Miranda-Tello ◽  
Ruslan Gabbasov ◽  
Ignacio Carvajal-Mariscal ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Liquid Steel ◽  
Mold Wall ◽  
Casting Machine ◽  
Submerged Entry Nozzle ◽  
Central Plane ◽  
Impact Point ◽  
Single Vortex ◽  
Hydrodynamic Analysis ◽  
Principal Characteristics

In vertical continuous casting machines the liquid steel from the tundish is poured into the mold through the Submerged Entry Nozzle (SEN). The shape and direction of the SEN exit jets affect the liquid steel dynamics inside the mold. This work quantifies the effect of the SEN pool on the principal characteristics of the jets emerging from it, precisely, the shape, the spread angles, and the mold impact point. Experimental and numerical simulations were carried out using a SEN simplified model, a square-shaped bore nozzle with square-shaped outlet ports whose length is minimal. These experiments showed two well-defined behaviors. When a single vortex dominates the hydrodynamics inside the simplified SEN, the exit jets spread out and are misaligned about the mold’s central plane. On the contrary, when the inner flow pattern shows two vortexes, the exit jets are compact and parallel to the mold wide walls. The measured difference on the jet’s falling angles is 5°, approximately, which implies that in an actual casting machine, the impingement point at the narrow mold wall would have a variation of 0.150 m. This hydrodynamic analysis would help design new SENs for continuous casting machines that improve steel quality.

scholarly journals The Ad Hoc Back-End of the BIRALET Radar to Measure Slant-Range and Doppler Shift of Resident Space Objects

Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 577
Author(s):  
Luca Schirru ◽  
Tonino Pisanu ◽  
Angelo Podda
Keyword(s):  
Doppler Shift ◽  
Space Debris ◽  
Ad Hoc ◽  
Low Earth Orbit ◽  
Slant Range ◽  
Radar Systems ◽  
The Earth ◽  
Space Objects ◽  
Resident Space Objects ◽  
Potential Issue

Space debris is a term for all human-made objects orbiting the Earth or reentering the atmosphere. The population of space debris is continuously growing and it represents a potential issue for active satellites and spacecraft. New collisions and fragmentation could exponentially increase the amount of debris and so the level of risk represented by these objects. The principal technique used for the debris monitoring, in the Low Earth Orbit (LEO) between 200 km and 2000 km of altitude, is based on radar systems. The BIRALET system represents one of the main Italian radars involved in resident space objects observations. It is a bi-static radar, which operates in the P-band at 410–415 MHz, that uses the Sardinia Radio Telescope as receiver. In this paper, a detailed description of the new ad hoc back-end developed for the BIRALET radar, with the aim to perform slant-range and Doppler shift measurements, is presented. The new system was successfully tested in several validation measurement campaigns, the results of which are reported and discussed.

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