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Articles 1 - 14 of 14
Full-Text Articles in Engineering
Development Of A Sensor Suite For Atmospheric Boundary Layer Measurement With A Small Multirotor Unmanned Aerial System, Kevin A. Adkins, Christopher J. Swinford, Peter D. Wambolt, Gordon Bease
Development Of A Sensor Suite For Atmospheric Boundary Layer Measurement With A Small Multirotor Unmanned Aerial System, Kevin A. Adkins, Christopher J. Swinford, Peter D. Wambolt, Gordon Bease
International Journal of Aviation, Aeronautics, and Aerospace
Small unmanned aerial systems (sUAS) are increasingly being used to conduct atmospheric research. Because of the dynamic nature and inhomogeneity of the atmospheric boundary layer (ABL), the ability of instrumented sUAS to make on-demand 3-dimensional high-resolution spatial measurements of atmospheric parameters makes them particularly suited to ABL investigations. Both fixed-wing and multirotor sUAS have been used for ABL investigations. Most investigations to date have included in-situ measurement of thermodynamic quantities such as temperature, pressure and humidity. When wind has been measured, a variety of strategies have been used. Two of the most popular techniques have been deducing wind from inertial …
Urban Flow And Small Unmanned Aerial System Operations In The Built Environment, Kevin A. Adkins
Urban Flow And Small Unmanned Aerial System Operations In The Built Environment, Kevin A. Adkins
International Journal of Aviation, Aeronautics, and Aerospace
The Federal Aviation Administration (FAA) has put forth a set of regulations (Part 107) that govern small unmanned aerial system (sUAS) operations. These regulations restrict unmanned aircraft (UA) from flying over people and their operation to within visual line of sight (VLOS). However, as new applications for unmanned aerial systems (UAS) are discovered, their capabilities improve, and regulations evolve, there is an increasing desire to undertake urban operations, such as urban air mobility, package delivery, infrastructure inspection, and surveillance. This built environment poses new weather hazards that include enhanced wind shear and turbulence. The smaller physical dimensions, lower mass and …
On Atmospheric Lapse Rates, Nihad E. Daidzic
On Atmospheric Lapse Rates, Nihad E. Daidzic
International Journal of Aviation, Aeronautics, and Aerospace
We have derived and summarized and most important atmospheric temperature lapse rates. ALRs essentially govern vertical atmospheric air stability and creation of some cloud types. The sensitivity analysis of various atmospheric lapse rates and their dependence on actual ideal-gas air properties and gravitational attraction was conducted for the first time to the best of our knowledge. SALR, which has DALR as the upper asymptote, showed steepest decrease at around 9 degrees Celsius then flattening out and apparently approaching another asymptotic solution which has not been investigated as it falls outside of the terrestrial temperature range. ISA lapse rates are adopted …
A New Model For Lifting Condensation Levels Estimation, Nihad E. Daidzic Ph.D., Sc.D.
A New Model For Lifting Condensation Levels Estimation, Nihad E. Daidzic Ph.D., Sc.D.
International Journal of Aviation, Aeronautics, and Aerospace
Knowledge of and the ability to predict lifting condensation levels (LCL) is important ingredient in weather predictions, cloud formation, planetary albedo and Earth’s energy balance. It is also essential topic in aviation safety and flight operations. In this article, we derive a new model of LCL and compare it to some older commonly-used models. This includes also the recently published Romps’ (2017) model. The new model presented here includes dependence, however weak, of the surface atmospheric pressure and the specific humidity on the LCL height and temperature. Such is not the case with widely used models and expressions by Espy …
Book Review: Fundamentals Of International Aviation, Alan Bender
Book Review: Fundamentals Of International Aviation, Alan Bender
International Journal of Aviation, Aeronautics, and Aerospace
Not applicable.
Quantitative Examination And Comparison Of Altimetry Rules-Of-Thumb For General Aviation, Thomas A. Guinn
Quantitative Examination And Comparison Of Altimetry Rules-Of-Thumb For General Aviation, Thomas A. Guinn
International Journal of Aviation, Aeronautics, and Aerospace
General aviation rules of thumb (ROTs) for density altitude and true altitude are examined and developed. Both ROTs originate from the same basic principle of hydrostatic balance, but differ significantly in the assumptions made regarding the atmospheric temperature profile. While the ROT for DA assumes a standard atmospheric vertical temperature lapse rate, the ROT for true altitude requires information regarding the observed layer-mean temperature of the atmosphere. Since the layer-mean temperature between the aircraft and the surface is typically unknown, it must be inferred from the temperature at a single level by again assuming a linear lapse rate. This method …
Quantifying The Effects Of Humidity On Density Altitude Calculations For Professional Aviation Education, Thomas A. Guinn, Randell J. Barry
Quantifying The Effects Of Humidity On Density Altitude Calculations For Professional Aviation Education, Thomas A. Guinn, Randell J. Barry
International Journal of Aviation, Aeronautics, and Aerospace
The effects of humidity on density altitude are quantified in detail and graphically represented as a function of temperature and dew-point temperature for ease of use in professional aviation education. A ten-year climatology of dew-point temperatures for various representative locations throughout the United States is created to provide a basis for comparison and use with the graphical displays. Density altitude is demonstrated to be a function only of dew-point temperature for a given pressure altitude. The absolute errors between density altitude calculations that incorporate humidity to those that do not are combined with linear regression techniques to create a simple …
Enhancing Quality Assurance Using Virtual Design Engineering: Case Study Of Space Shuttle Challenger, Kouroush Jenab, Scot Paterson
Enhancing Quality Assurance Using Virtual Design Engineering: Case Study Of Space Shuttle Challenger, Kouroush Jenab, Scot Paterson
International Journal of Aviation, Aeronautics, and Aerospace
Virtual Design Engineering is an emerging method of increasing quality of systems. Including Virtual Design as a part of the traditional established Failure Mode, Effects, and Criticality Analysis process greatly enhances hazard and risk analysis while reducing overall costs. In this study these enhancements are explored and expanded upon to discover how overall system quality could be increased and all stakeholders could more accurately understand the hazards involved. Stakeholder misunderstanding or misapplication of hazards is of great importance to complex systems. An illustrative example of how these factors could have changed the outcome of a real-world engineering failure is provided.
Examining Unmanned Aerial System Threats & Defenses: A Conceptual Analysis, Ryan J. Wallace, Jon M. Loffi
Examining Unmanned Aerial System Threats & Defenses: A Conceptual Analysis, Ryan J. Wallace, Jon M. Loffi
International Journal of Aviation, Aeronautics, and Aerospace
The integration of unmanned aerial systems (UAS) into the already complex global aviation system presents new and unique hazards. While many studies have addressed the potential safety concerns of UAS integration, little research has been dedicated to the potential security implications. This study sought to identify potential uses and adaptations of civil UAS systems as weapons of terrorism or crime and potential UAS defenses. Researchers examined 68 academic studies, unclassified government reports, and news articles using Conceptual Analysis to systematically capture and categorize various threats. Using the collected data, researchers developed a UAS threat model for categorically evaluating potential threats. …
Aviation Bird Hazard In Nexrad Dual Polarization Weather Radar Confirmed By Visual Observations, Bradley M. Muller, Frederick R. Mosher, Christopher G. Herbster, Anthony T. Brickhouse
Aviation Bird Hazard In Nexrad Dual Polarization Weather Radar Confirmed By Visual Observations, Bradley M. Muller, Frederick R. Mosher, Christopher G. Herbster, Anthony T. Brickhouse
International Journal of Aviation, Aeronautics, and Aerospace
Birds represent a significant hazard to flying aircraft as illustrated by the “Miracle on the Hudson” encounter in 2009 between U.S. Airways Flight 1549 and a flock of Canada Geese, forcing the flight to ditch in the river. Birds are common in the skies over Florida during the spring migration season, and often appear in the National Weather Service’s (NWS) NEXRAD weather radar imagery as an easily recognizable signature known as a “roost ring.” This paper presents a NEXRAD roost ring case in central Florida in a rare instance where the signatures were confirmed by visual observations of the birds. …
Global Optimized Isothermal And Nonlinear Models Of Earth’S Standard Atmosphere, Nihad E. Daidzic, Ph.D.,
Global Optimized Isothermal And Nonlinear Models Of Earth’S Standard Atmosphere, Nihad E. Daidzic, Ph.D.,
International Journal of Aviation, Aeronautics, and Aerospace
Both, a global isothermal temperature model and a nonlinear quadratic temperature model of the ISA was developed and presented here. Constrained optimization techniques in conjunction with the least-square-root approximations were used to design best-fit isothermal models for ISA pressure and density changes up to 47 geopotential km for NLPAM, and 86 orthometric km for ISOAM respectively. The mass of the dry atmosphere and the relevant fractional-mass scale heights have been computed utilizing the very accurate eight-point Gauss-Legendre numerical quadrature for both ISOAM and NLPAM. Both, the ISOAM and the NLPAM represent viable alternatives to ISA in many practical applications and …
Bio-Fuel Alternatives In South African Airways (Saa) Operations - Is It An Effective Response To Vulnerability Over Carbon Taxes And Penalty?, Daniel Kwasi Adjekum
Bio-Fuel Alternatives In South African Airways (Saa) Operations - Is It An Effective Response To Vulnerability Over Carbon Taxes And Penalty?, Daniel Kwasi Adjekum
International Journal of Aviation, Aeronautics, and Aerospace
The paper did a comparative analysis of the carbon emission and European Union Emission Trading Surcharges (EU ETS) of South African Airways (SAA) current fleet that used aviation jet A1 fuel and the same fleet if it had used a 25% bio-fuel ‘drop in’ for the European routes within the first quarter of the 2014 flying year (FY 14). Operational data in terms of the flight scheduled, aircraft type, total time enroute, route stage length, passenger estimates were obtained through SAA’s flight operations website. An independent t–test was conducted to compare means of the emissions. The mean carbon dioxide …
Numerical Model Derived Altimeter Correction Maps For Non-Standard Atmospheric Temperature And Pressure, Thomas A. Guinn, Frederick R. Mosher
Numerical Model Derived Altimeter Correction Maps For Non-Standard Atmospheric Temperature And Pressure, Thomas A. Guinn, Frederick R. Mosher
International Journal of Aviation, Aeronautics, and Aerospace
Altimeter corrections for non-standard temperature pose a challenge because accurate calculations require detailed knowledge of the temperature structure of the atmosphere between the surface and the aircraft. By applying basic hypsometric formulae to high resolution numerical model temperature and moisture output, detailed maps of current and forecasted corrected D-values are created. Corrected D-values provide the altitude difference between the true altitude and the indicated altitude from a pressure altimeter. Unlike standard D-values, the corrected D-value corrects for non-standard pressure in addition to non-standard temperature and is therefore useful for flights below class A airspace. Maps of corrected D-value may help …
Efficient General Computational Method For Estimation Of Standard Atmosphere Parameters, Nihad E. Daidzic Ph.D., Sc.D.
Efficient General Computational Method For Estimation Of Standard Atmosphere Parameters, Nihad E. Daidzic Ph.D., Sc.D.
International Journal of Aviation, Aeronautics, and Aerospace
Knowledge of standard air temperature, pressure, density, speed of sound, and viscosity as a function of altitude is essential information in aircraft design, performance testing, pressure altimeter calibration, and several other aeronautical engineering and aviation science applications. A new efficient computational method for rapid calculations of standard atmospheric parameters up to 86 orthometric km is presented. Additionally, mass and weight of each standard atmospheric layer were calculated using a numerical integration method. The sum of all fractional masses and weights represents the total mass and weight of Earth’s atmosphere. The results obtained here agree well with measurements and models of …