Injection of high-speed solid D2 pellets using a “Direct-Line-of-Sight” (DLS) guide tube

2021 ◽  
Vol 162 ◽  
pp. 112138
Author(s):  
Antonio Frattolillo ◽  
Larry R. Baylor ◽  
Christian Day ◽  
Trey E. Gebhart ◽  
Peter T. Lang ◽  
...  
Keyword(s):  
High Speed ◽  
Line Of Sight ◽  
Guide Tube

scholarly journals Controllers to Chase a High-Speed Evader Using a Pursuer with Variable Speed

2018 ◽  
Vol 8 (10) ◽  
pp. 1976 ◽  
Author(s):  
Jonghoek Kim
Keyword(s):  
Optical Flow ◽  
High Speed ◽  
Angular Rate ◽  
Relative Distance ◽  
Line Of Sight ◽  
Terminal Phase ◽  
Relative Speed ◽  
Variable Speed

This paper proposes a chasing controller to enable a pursuer to chase a high-speed evader such that the relative distance between the evader and the pursuer monotonically decreases as time passes. Our controller is designed to assure that the angular rate of Line-of-Sight joining the pair (the pursuer and the evader) is exactly zero at all time indexes. Assuming that the pursuee can readily observe optical flow, but only poorly detect looming, this pursuer’s movement is hardly detected by the pursuee. Consider the terminal phase when the pursuer is sufficiently close to the evader. As we slow down the relative speed of the pursuer with respect to the evader, we can reduce the probability of missing the high-speed evader. Thus, our strategy is to make the pursuer decrease its speed in the terminal phase, while ensuring that the distance between the evader and the pursuer monotonically decreases as time passes. The performance of our controller is verified utilizing MATLAB simulations.

scholarly journals Line of Sight Correction of High-Speed Liquid Crystal Using Overdriving Technology

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1477
Author(s):  
Hongyang Guo ◽  
Qing Li ◽  
Yangjie Xu ◽  
Yongmei Huang ◽  
Shengping Du
Keyword(s):  
Liquid Crystal ◽  
Response Time ◽  
High Speed ◽  
Pulse Width Modulation ◽  
Response Speed ◽  
Line Of Sight ◽  
Processing Unit ◽  
Driving Voltage ◽  
Light Modulator ◽  
Central Processing

In the line of sight correction system, the response time of the liquid crystal spatial light modulator under the normal driving voltage is too long to affect system performance. On the issues, an overdriving method based on a Field-Programmable Gate Array (FPGA) is established. The principle of the overdrive is to use a higher voltage difference to achieve a faster response speed of liquid crystal. In this scheme, the overdriving look-up table is used to seek the response time of the quantized phase, and the liquid crystal electrode is driven by Pulse–Width Modulation (PWM). All the processes are performed in FPGA, which releases the central processing unit (CPU) memory and responds faster. Adequate simulations and experiments are introduced to demonstrate the proposed method. The overdriving experiment shows that the rising response time is reduced from 530 ms to 34 ms, and the falling time is from 360 ms to 38 ms under the overdriving voltage. Typical light tracks are imitated to evaluate the performance of the line of sight correction platform. Results show that using the overdrive the −3 dB rejection frequency was increased from 1.1 Hz to 2.6 Hz. The suppression ability of the overdrive is about −20 dB at 0.1 Hz, however the normal-driving suppression ability is only about −13 dB.

scholarly journals Resolving Last-Mile Connectivity Issues in Botswana Using WiMAX IEEE802

2021 ◽  
Author(s):  
Malebogo Mokeresete ◽  
Bukohwo Michael Esiefarienrhe
Keyword(s):  
Developing Countries ◽  
Rural Areas ◽  
High Speed ◽  
Simulation Method ◽  
Line Of Sight ◽  
Infrastructure Development ◽  
Ieee 802.16E ◽  
Access Technology ◽  
Regulatory Standards ◽  
Last Mile

Amongst advantages of using Worldwide Interoperability Microwave Access (WiMAX) technology at the last-mile level as access technology include an extensive range of 50 km Line of Sight (LOS), 5 to 15 km Non-Line of Sight and few infrastructure installations compared to other wireless broadband access technologies. Despite positive investments in ICT fibre infrastructure by developing countries, including Botswana, servicing end-users is subjected to high prices and marginalised. The alternative, the Wi-Fi hotspot initiative by the Botswana government, falls far as a solution for last-mile connectivity and access. This study used OPNET simulation modeller 14,5 to investigate whether Botswana’s national broadband project could adopt WiMAX IEEE 802.16e as an access technology. Several developing countries in Africa and the world use WiMAX technology at access level and gain impressive results. The rampant lack of infrastructure development and the need to provide high-speed technology has necessitated such investigation. Therefore, using the simulation method, this paper evaluates the WiMAX IEEE 802.16e/m over three subscriber locations in Botswana. The results obtained indicate that the deployment of the WiMAX IEEE 802.16e standard can solve most of the deployment issues and access at the last-mile level. Although the findings suggest that WiMAX IEEE 802.16e is more suitable for high-density areas, it could also solve rural areas’ infrastructure development challenges and provide required high-speed connectivity access. However, unlike the Wi-Fi initiative, which requires more infrastructure deployment and less on institutional and regulatory frameworks, the deployment of WiMAX IEEE802.16e requires institutional and regulatory standards.

scholarly journals Attack behaviour in naïve Gyrfalcons is modelled by the same guidance law as in Peregrines, but at a lower guidance gain

2021 ◽  
pp. jeb.238493
Author(s):  
Caroline H. Brighton ◽  
Katherine E. Chapman ◽  
Nicholas C. Fox ◽  
Graham K. Taylor
Keyword(s):  
High Speed ◽  
Angular Rate ◽  
Species Level ◽  
Line Of Sight ◽  
Proportional Navigation ◽  
Evolutionary Origins ◽  
Guidance Law ◽  
Flight Morphology ◽  
Aerial Hunting ◽  
The Individual

The aerial hunting behaviours of birds are strongly influenced by flight morphology and ecology, but little is known of how this relates to the behavioural algorithms guiding flight. Here we use GPS loggers to record the attack trajectories of captive-bred Gyrfalcons (Falco rusticolus) during their maiden flights against robotic aerial targets, which we compare to existing flight data from Peregrines (Falco peregrinus). The attack trajectories of both species are well modelled by a proportional navigation (PN) guidance law, which commands turning in proportion to the angular rate of the line-of-sight to target, at a guidance gain. However, naïve Gyrfalcons operate at significantly lower values of N than Peregrines, producing slower turning and a longer path to intercept. Gyrfalcons are less manoeuvrable than Peregrines, but physical constraint is insufficient to explain the lower values of N we found, which may reflect either the inexperience of the individual birds or ecological adaptation at the species level. For example, low values of N promote the tail-chasing behaviour that is typical of wild Gyrfalcons and which apparently serves to tire their prey in a prolonged high-speed pursuit. Likewise, during close pursuit of typical fast evasive prey, PN will be less prone to being thrown off by erratic target manoeuvres at low guidance gain. The fact that low-gain PN successfully models the maiden attack flights of Gyrfalcons suggests that this behavioural algorithm is embedded in a guidance pathway ancestral to the clade containing Gyrfalcons and Peregrines, though perhaps with much deeper evolutionary origins.

Multicolor Techniques for Identification and Filtering of Burst Signals in Jet Engine Pyrometers

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Jordi Estevadeordal ◽  
Guanghua Wang ◽  
Nirm Nirmalan ◽  
Anquan Wang ◽  
Sean P. Harper ◽  
...  
Keyword(s):  
High Speed ◽  
Aircraft Engine ◽  
Line Of Sight ◽  
Research Projects ◽  
Jet Engine ◽  
Root Cause ◽  
Voltage Signal ◽  
Signal Output ◽  
Simulation Results ◽  
Radiant Temperature

A Defense Advanced Research Projects Agency (DARPA)-funded multicolor pyrometry (MCP) experiment was carried out on a government-provided aircraft engine to study the nature of hot particulate bursts generated from the combustor at certain engine conditions. These bursts of hot particulates lead to intermittent high-voltage signal output from the line-of-sight (LOS) pyrometer that is ultimately detected and used by the onboard digital engine controller (DEC). The investigation used a high-speed MCP system designed to detect bursts and identify their properties. Results of the radiant temperature, multicolor temperature, and apparent emissivity are presented. The results indicated that the apparent emissivity calculated during the signal burst was lower than that of the blade. The root cause for the signal burst was identified as soot particles generated as a by-product of combustion under certain conditions. This conclusion was drawn based on both experimental and simulation results. Technical strategies to separate, reduce, or remove the burst signal are proposed.

scholarly journals Performance Evaluation of Adaptive Continuous Wavelet Transform based Rake Receiver for UWB Systems

2018 ◽  
Vol 8 (5) ◽  
pp. 3444
Author(s):  
Ch. Navitha ◽  
K. Sivani ◽  
K. Ashoka Reddy
Keyword(s):  
Wavelet Transform ◽  
Continuous Wavelet Transform ◽  
High Speed ◽  
Channel Model ◽  
Rake Receiver ◽  
Training Data ◽  
Ultra Wideband ◽  
Line Of Sight ◽  
Continuous Wavelet ◽  
Channel Models

This paper proposes an adaptive continuous wavelet transform (ACWT) based Rake receiver to mitigate interference for high speed ultra wideband (UWB) transmission. The major parts of the receiver are least mean square (LMS) adaptive equalizer and N-selective maximum ratio combiner (MRC). The main advantage of using continuous wavelet rake receiver is that it utilizes the maximum bandwidth (7.5GHz) of the UWB transmitted signal, as announced by the Federal Communication Commission (FCC). In the proposed ACWT Rake receiver, the weights and the finger positions are updated depending upon the convergence error over a period in which training data is transmitted. Line of sight (LOS) channel model (CM1 from 0 to 4 meters) and the Non line of sight (NLOS) channel models (CM, CM3 and CM4) are the indoor channel models selected for investigating in this research . The performance of the proposed adaptive system   is evaluated by comparing with conventional rake and continuous wavelet transform (CWT) based rake. It showed an improved performance in all the different UWB channels (CM1 to CM4) for rake fingers of 2, 4 and 8. Simulations showed that for 8 rake fingers, the proposed adaptive CWT rake receiver has shown an SNR improvement of 2dB, 3dB, 10dB and 2dB respectively over CWT rake receiver in different UWB channels CM1, CM2, CM3 and CM4.

scholarly journals Non-line-of-sight methodology for high-speed wireless optical communication in highly turbid water

2020 ◽  
Vol 461 ◽  
pp. 125264 ◽  
Author(s):  
Xiaobin Sun ◽  
Meiwei Kong ◽  
Omar Alkhazragi ◽  
Chao Shen ◽  
Ee-Ning Ooi ◽  
...  
Keyword(s):  
Optical Communication ◽  
High Speed ◽  
Line Of Sight ◽  
Turbid Water ◽  
Wireless Optical Communication ◽  
Non Line Of Sight

scholarly journals Nonisotropic Scattering Characteristic in an Alternant Tree-Blocked Viaduct Scenario on High-Speed Railway at 2.35 GHz

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Rongchen Sun ◽  
Cheng Tao ◽  
Liu Liu ◽  
Zhenhui Tan ◽  
Lingwen Zhang ◽  
...  
Keyword(s):  
High Speed ◽  
Channel Model ◽  
Radio Channel ◽  
Statistical Characteristics ◽  
Real Field ◽  
Line Of Sight ◽  
Angle Of Arrival ◽  
High Speed Railway ◽  
Scattering Characteristic ◽  
Nonisotropic Scattering

This paper presents the nonisotropic scattering characteristic of the mobile radio channel in an alternant tree-blocked viaduct scenario on high-speed railway (HSR) by real field measuring at 2.35 GHz. An angle of arrival (AOA) probability density function (PDF) is proposed for the nonuniform AOA at the mobile caused by stochastically distributed scatterers. Two Von Mises angular distributions with broad applicability are used to represent the line of sight (LOS) component and part of the scattering component in the AOA model. Based on such a PDF statistical characteristics of Ricean factor,κ, and AOA of the scattering component are modeled in LOS and obstructed line of sight (OLOS) cases, respectively. The results may give a meaningful and accurate channel model and could be utilized in HSR viaduct scenario evaluation.

scholarly journals Laser-Plasma Spatiotemporal Cyanide Spectroscopy and Applications

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 615 ◽  
Author(s):  
Christian G. Parigger ◽  
Christopher M. Helstern ◽  
Benjamin S. Jordan ◽  
David M. Surmick ◽  
Robert Splinter
Keyword(s):  
High Speed ◽  
Peak Power ◽  
Optical Breakdown ◽  
Line Of Sight ◽  
High Peak Power ◽  
Molecular Spectra ◽  
Plasma Distribution ◽  
A Cell ◽  
Inversion Techniques ◽  
Shutter Speed

This article reports new measurements of laser-induced plasma hypersonic expansion measurements of diatomic molecular cyanide (CN). Focused, high-peak-power 1064 nm Q-switched radiation of the order of 1 TW/cm 2 generated optical breakdown plasma in a cell containing a 1:1 molar gas mixture of N 2 and CO 2 at a fixed pressure of 1.1 × 10 5 Pascal and in a 100 mL/min flow of the mixture. Line-of-sight (LOS) analysis of recorded molecular spectra indicated the outgoing shockwave at expansion speeds well in excess of Mach 5. Spectra of atomic carbon confirmed increased electron density near the shockwave, and, equally, molecular CN spectra revealed higher excitation temperature near the shockwave. Results were consistent with corresponding high-speed shadowgraphs obtained by visualization with an effective shutter speed of 5 nanoseconds. In addition, LOS analysis and the application of integral inversion techniques allow inferences about the spatiotemporal plasma distribution.

Sign in / Sign up

Export Citation Format

Share Document