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Articles 8461 - 8490 of 11122
Full-Text Articles in Engineering
Space Systems Design: Building A Satellite To Detect Forest Fires, Robert J. Twiggs
Space Systems Design: Building A Satellite To Detect Forest Fires, Robert J. Twiggs
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint Presentation created by Professor Bob Twiggs titled "Space Systems Design Building a Satellite to Detect Forest Fires" from September 10, 2009.
Precision Navigation Using Pre-Georegistered Map Data, Frederick C. Webber
Precision Navigation Using Pre-Georegistered Map Data, Frederick C. Webber
Theses and Dissertations
Navigation performance in small unmanned aerial vehicles (UAVs) is adversely affected by limitations in current sensor technology for small, lightweight sensors. Because most UAVs are equipped with cameras for mission-related purposes, it is advantageous to utilize the camera to improve the navigation solution. This research improves navigation by matching camera images to a priori georegistered image data and combining this update with existing image-aided navigation technology. The georegistration matching is done by projecting the images into the same plane, extracting features using the techniques Scale Invariant Feature Transform (SIFT) [5] and Speeded-Up Robust Features (SURF) [3]. The features are matched …
Pulsed Film Cooling On A Turbine Blade Leading Edge, James L. Rutledge
Pulsed Film Cooling On A Turbine Blade Leading Edge, James L. Rutledge
Theses and Dissertations
Unsteadiness in gas turbine film cooling jets may arise due to inherent unsteadiness of the flow through an engine or may be induced as a means of flow control. The traditional technique used to evaluate the performance of a steady film cooling scheme is demonstrated to be insufficient for use with unsteady film cooling and is modified to account for the cross coupling of the time dependent adiabatic effectiveness and heat transfer coefficient. The addition of a single term to the traditional steady form of the net heat flux reduction equation with time averaged quantities accounts for the unsteady effects. …
F-16 Ventral Fin Buffet Alleviation Using Piezoelectric Actuators, Joseph S. Browning
F-16 Ventral Fin Buffet Alleviation Using Piezoelectric Actuators, Joseph S. Browning
Theses and Dissertations
Buffet-induced vibrations can have a disastrous impact on aircraft structures. Early attempts at combating buffet vibrations included passive methods such as structural enhancements and leading edge fences. Active methods have shown greater promise, including active airflow control, control surface modulation, and active structural control using piezoelectric actuators. Surface mounted piezoelectric actuators impart directional strain reducing the negative effects associated with harmful vibration. The Block-15 F-16 ventral fin represents an aircraft structure prone to failure when subjected to the buffet field from the wake of a LANTIRN pod. This research takes advantage of the susceptibility to buffet vibration of the Block …
The Need For An Integrated Small Satellite Space Programme: Perspective From The Sumbandila Missions Operations, Pieter Kotze
The Need For An Integrated Small Satellite Space Programme: Perspective From The Sumbandila Missions Operations, Pieter Kotze
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint Presentation created by Pieter Kotze titled "The need for an integrated small satellite space programme: Perspective from the Sumbandila Missions Operations" from September 9, 2009.
Opportunities For Small Satellite Programs Provided By The Falcon Family Of Launch Vehicles, Spacex
Opportunities For Small Satellite Programs Provided By The Falcon Family Of Launch Vehicles, Spacex
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint Presentation created by SpaceX titled "Opportunities for Small Satellite Programs Provided by the Falcon Family of Launch Vehicles" from September 9, 2009.
Satedu, University Didactic Satellite For Hands-On Training And Easy Access To Low Cost Small Satellite Missions, Esau Vicente Vivas
Satedu, University Didactic Satellite For Hands-On Training And Easy Access To Low Cost Small Satellite Missions, Esau Vicente Vivas
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint presentation created by Esaú Vicente Vivas titled "SATEDU, University Didactic Satellite for Hands-on Training and Easy Access to Low Cost Small Satellite Missions" from September 9, 2009.
Isc Kosmotras Dnepr Cluster Launches: Large-Scale Opportunities For Small Satellites, Isc Kosmotras
Isc Kosmotras Dnepr Cluster Launches: Large-Scale Opportunities For Small Satellites, Isc Kosmotras
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint presentation created by the ISC Kosmotras titled "ISC Kosmotras DNEPR Cluster Launches: Large-Scale Opportunities for Small Satellites" from September 9, 2009.
Netherlands Antilles Satellite Orbit Development, Leonardo De Abreu Ladeira
Netherlands Antilles Satellite Orbit Development, Leonardo De Abreu Ladeira
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint Presentation created by Leonardo de Abreu Ladeira titled "Netherlands Antilles Satellite Orbit Development" from September 9, 2009.
Least-Squares, Continuous Sensitivity Analysis For Nonlinear Fluid-Structure Interaction, Douglas P. Wickert
Least-Squares, Continuous Sensitivity Analysis For Nonlinear Fluid-Structure Interaction, Douglas P. Wickert
Theses and Dissertations
A least-squares, continuous sensitivity analysis method is developed for transient aeroelastic gust response problems to support computationally efficient analysis and optimization of aeroelastic design problems. A key distinction between the local and total derivative forms of the sensitivity system is introduced. The continuous sensitivity equations and sensitivity boundary conditions are derived in local derivative form which is shown to be superior for several applications. The analysis and sensitivity problems are both posed in a first-order form which is amenable to a solution using the least-squares finite element method. Several example and validation problems are presented and solved, including elasticity, fluid, …
Alternative Methods To Standby Gain Scheduling Following Air Data System Failure, Matthew W. Coldsnow
Alternative Methods To Standby Gain Scheduling Following Air Data System Failure, Matthew W. Coldsnow
Theses and Dissertations
The United States Air Force has advanced fighter aircraft that lose the ability to operate in a large portion of their operating flight envelope when an air data system failure is experienced. These aircraft are reverted to a fixed set of standby-gains that limit their maneuverability, degrade handling qualities, and increase susceptibility to departure. The purpose of this research was to determine if three alternative methods of standby-gain-scheduling could provide robust control with minimal performance degradation despite the lack of air data. To accomplish this, three methods of standby-gain-scheduling were developed, integrated, and tested in the Infinity Cube simulator at …
Using Small Satellites For Low Cost Space Education & Science Missions, Robert J. Twiggs
Using Small Satellites For Low Cost Space Education & Science Missions, Robert J. Twiggs
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint Presentation created by Professor Bob Twiggs titled "Using Small Satellites for Low Cost Space Education & Science Missions" from September 8, 2009.
Itu Radio Regulations Related To N-Gso Satellites, International Telecommunication Union
Itu Radio Regulations Related To N-Gso Satellites, International Telecommunication Union
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint Presentation created by the International Telecommunication Union titled "ITU Radio Regulations related to N-GSO satellites" from September 8, 2009.
Indian Launch Vehicle Programme: An Overview, Indian Space Research Organization
Indian Launch Vehicle Programme: An Overview, Indian Space Research Organization
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint Presentation created by Indian Space Research Organization titled "Indian Launch Vehicle Programme: An Overview" from September 6, 2009.
Avoiding Veer-Off Accidents On Contaminated Runways, Nihad E. Daidzic
Avoiding Veer-Off Accidents On Contaminated Runways, Nihad E. Daidzic
Aviation Department Publications
No abstract provided.
Phase Change Mechanisms During Femtosecond Laser Pulse Train Ablation Of Nickel Thin Films, Xin Li, Lan Jiang, Hai-Lung Tsai
Phase Change Mechanisms During Femtosecond Laser Pulse Train Ablation Of Nickel Thin Films, Xin Li, Lan Jiang, Hai-Lung Tsai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The mechanisms of nickel thin films irradiated by femtosecond laser pulse trains are studied by a model using molecular dynamics simulations and two-temperature model. It is found that the pulse train technology can change energy transport and corresponding phase change processes. Compared with single pulse ablation at the same total fluence, the pulse trains lead to (1) lower ablation rate with more and smaller uniform nanoparticles, (2) higher film surface temperatures and longer thermalization time, (3) much lower electron thermal conductivity that can further control heat-affected zone, (4) significantly smaller film compressive stresses and tensile stresses which reduce microcracks, and …
Orbital Propagators For Horizon Simulation Framework, Mitra Farahmand
Orbital Propagators For Horizon Simulation Framework, Mitra Farahmand
Master's Theses
This thesis describes the models of four common orbital propagators and outlines the process of integrating them into the Horizon Simulation Framework (HSF). The results of the Two-Body, J2, and J4 propagators from the HSF are then compared against the outcomes of these propagators in MATLAB and Satellite Toolkit (STK). The MATLAB algorithms verify the functionality of the propagators and determine the accuracy of the HSF implementation. The compassion against STK validates the formulation of the HSF propagators. In order to equip the HSF with a more precise means of orbit determination, adding the Simplified General Perturbations 4 (SGP4) propagator …
Rayleigh Flow Of Two-Phase Nitrous Oxide As A Hybrid Rocket Nozzle Coolant, Lauren May Nelson
Rayleigh Flow Of Two-Phase Nitrous Oxide As A Hybrid Rocket Nozzle Coolant, Lauren May Nelson
Master's Theses
The Mechanical Engineering Department at California Polytechnic State University in San Luis Obispo currently maintains a lab-scale hybrid rocket motor for which nitrous oxide is utilized as the oxidizer in the combustion system. Because of its availability, the same two-phase (gas and liquid) nitrous oxide that is used in the combustion system is also routed around the throat of the hybrid rocket’s converging-diverging nozzle as a coolant. While this coolant system has proven effective empirically in previous tests, the physics behind the flow of the two-phase mixture is largely unexplained. This thesis provides a method for predicting some of its …
Spacecraft Attitude Control (Mission Design), Norhizam Hamzah
Spacecraft Attitude Control (Mission Design), Norhizam Hamzah
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint Presentation created by Norhizam Hamzah titled "Spacecraft Attitude Control (Mission Design)" from September 10, 2009.
Turkish Satellite Technology Applications For Sustainable Development And Capacity Building, Burcu Dikmen
Turkish Satellite Technology Applications For Sustainable Development And Capacity Building, Burcu Dikmen
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint Presentation created by Burcu Dikmen titled "Turkish Satellite Technology Applications for Sustainable Development and Capacity Building" from September 8, 2009.
The Role Of Education In Small Satellite Programmes, Olaleye Salu
The Role Of Education In Small Satellite Programmes, Olaleye Salu
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint presentation created by Olaleye Salu titled "The Role of Education in Small Satellite Programmes" from September 9, 2009.
Unmanned Aircraft System Propulsion Systems Technology Survey, Christopher Griffis, Timothy Wilson, Jeffrey Schneider, Peter Pierpont
Unmanned Aircraft System Propulsion Systems Technology Survey, Christopher Griffis, Timothy Wilson, Jeffrey Schneider, Peter Pierpont
Publications
This technology survey is an investigation of various propulsion systems used in Unmanned Aircraft Systems (UAS). Discussed are existing and near-future propulsion mechanisms of UAS, such as reciprocating piston engines, Wankel rotary engines, gas turbine engines, rocket-powered systems, electric motors, and battery-based systems. Also discussed are systems that use proton exchange membrane fuel cells, photovoltaics, ultracapacitors, and propellers. Each system is described in reference to a larger conceptual framework, with instances and profiles of existing UAS employing the system being described. Advantages and disadvantages of each type of propulsion system are identified along with associated technical issues and their respective …
Heavy-Fueled Intermittent Ignition Engines: Technical Issues, Jeffrey Arthur Schneider, Timothy Wilson, Christopher Griffis, Peter Pierpont
Heavy-Fueled Intermittent Ignition Engines: Technical Issues, Jeffrey Arthur Schneider, Timothy Wilson, Christopher Griffis, Peter Pierpont
Publications
This report contains an overview of the technology and engineering issues with nonturbine heavy-fueled engines for general aviation aircraft and Unmanned Aircraft Systems. In recent years, interest in these types of engines has grown, partly due to the cost, safety, and worldwide availability of gasoline fuels. Within 3 to 5 years, up to five engines will seek Federal Aviation Administration certification as heavy-fuel powerplants. Although there has been some progress, there is no universal standard for certification of these engines (under Title 14 Code of Federal Regulations (CFR) Part 33), or their installation into normal category fixed-wing aircraft or rotorcraft …
The Navigation Potential Of Ground Feature Tracking, Guner Mutlu
The Navigation Potential Of Ground Feature Tracking, Guner Mutlu
Theses and Dissertations
This research effort examines the reduction of error in inertial navigation aided by vision. This is part of an effort focused on navigation in a GPS denied environment. The navigation concept examined here consists of two main steps. First, extract the position of a tracked ground object using vision and geo-locate it in 3 dimensional navigation frame. In this first step multiple positions of the UAV are assumed known; think of a synthetic aperture. The only information about the tracked ground objects/features is the unit vector that points to the objects from the center of the camera. Two such vectors …
The Interaction Between Throttling And Thrust Vectoring Of An Annular Aerospike Nozzle, David Michael Imbaratto
The Interaction Between Throttling And Thrust Vectoring Of An Annular Aerospike Nozzle, David Michael Imbaratto
Master's Theses
Applied research and testing has been conducted at the Cal Poly San Luis Obispo High-pressure Blow-Down facility to study the affects of throttling in a thrust-vectored aerospike nozzle. This study supports the ongoing research at Cal Poly to effectively thrust vector a hybrid rocket motor. Such thrust vectoring is achieved by small secondary ports in the nozzle body that are perpendicular to the main nozzle. The testing conducted included characterizing and comparing the performance of a straight aerospike nozzle to that of a thrust-vectored aerospike nozzle. Throttling effects on the aerospike nozzle in an unvectored and in a vectored configuration …
Formation Flight Of Earth Satellites On Kam Tori, Christopher T. Craft
Formation Flight Of Earth Satellites On Kam Tori, Christopher T. Craft
Theses and Dissertations
Kolmogorov, Arnold and Moser (KAM) theory provides that orbits of satellites whose dynamics are representable by an integrable Hamiltonian plus a small, real perturbation lie on tori in phase space and remain on the KAM tori for all time, unless acted upon by a non-conservative force. A refined technique for constructing KAM tori for Earth-orbiting satellites is developed and implemented using numerically integrated orbital data for hypothetical satellites and involving methods of Fourier analysis and spectral decomposition. Definition of satellite formations on the KAM tori is performed and analyses conducted to investigate both constellations with large separations and clusters with …
Efficient Simulation Of Fluid Flow, David Hannasch, Monika Neda
Efficient Simulation Of Fluid Flow, David Hannasch, Monika Neda
Undergraduate Research Opportunities Program (UROP)
We are computationally investigating fluid flow models for physically correct predictions of flow structures. Models based on the idea of filtering the small scales/structures and also the Navier-Stokes equations which are the fundamental equations of fluid flow, are numerically solved via the continuous finite element method. Crank-Nicolson and fractional-step theta scheme are used for the discretization of the time derivative, while the Taylor-Hood and Mini elements are used for the discretization is space. The effectiveness of these numerical discretizations in time and space are examined by studying the accuracy of fluid characteristics, such as drag, lift and pressure drop.
Evaluation Of Direct Diode Laser Deposited Stainless Steel 316l On 4340 Steel Substrate For Aircraft Landing Gear Application, Tian Fu, Todd E. Sparks, Frank W. Liou, Joseph William Newkirk, Zhiqiang Fan, Syamala Rani Pulugurtha, Jianzhong Ruan, Hsin-Nan Chou
Evaluation Of Direct Diode Laser Deposited Stainless Steel 316l On 4340 Steel Substrate For Aircraft Landing Gear Application, Tian Fu, Todd E. Sparks, Frank W. Liou, Joseph William Newkirk, Zhiqiang Fan, Syamala Rani Pulugurtha, Jianzhong Ruan, Hsin-Nan Chou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
300M steel is used extensively for aircraft landing gears because of its high strength, ductility and toughness. However, like other high-strength steels, 300M steel is vulnerable to corrosion fatigue and stress corrosion cracking, which can lead to catastrophic consequences in the landing gear. Stainless steels offer a combination of corrosion, wear, and fatigue properties. But for an aircraft landing gear application a higher surface hardness is required. A laser cladding process with fast heating and cooling rates can improve the surface hardness. AISI 4340 steel is used as a lower cost alternative to 300M due to its similar composition. In …
Development Of A High Performance Micropropulsion System For Cubesats, Christopher Lorian Biddy
Development Of A High Performance Micropropulsion System For Cubesats, Christopher Lorian Biddy
Master's Theses
Picosatellites are defined as satellites with a mass between 0.1 and 1kg (Miniaturized satellite). Picosatellites are typically designed to work together or function in formations (Miniaturized satellite). A specific type of Picosatellite known as CubeSats were introduced in 1999 and since then have increased in popularity so that there are now over 80 CubeSat programs around the world. CubeSats are defined as cubic units 10cm on each side and no more than 1kg in mass. CubeSats are required to conform to the CubeSat Standard created by California Polytechnic State University and Stanford University and be compatible with Cal Poly’s P-POD …
Developing Abrasion Test Standards For Evaluating Lunar Construction Materials, Ryan L. Kobrick, David M. Klaus, Kenneth W. Street
Developing Abrasion Test Standards For Evaluating Lunar Construction Materials, Ryan L. Kobrick, David M. Klaus, Kenneth W. Street
Publications
Operational issues encountered by Apollo astronauts relating to lunar dust were catalogued, including material abrasion that resulted in scratches and wear on spacesuit components, ultimately impacting visibility, joint mobility and pressure retention. Standard methods are being developed to measure abrasive wear on candidate construction materials to be used for spacesuits, spacecraft, and robotics. Calibration tests were conducted using a standard diamond stylus scratch tip on the common spacecraft structure aluminum, Al 6061-T6. Custom tips were fabricated from terrestrial counterparts of lunar minerals for scratching Al 6061-T6 and comparing to standard diamond scratches. Considerations are offered for how to apply standards …