Improvements to the FATOLA computer program including nosewheel steering: Supplemental instruction manual

Modifications to a multidegree of freedom flexible aircraft take-off and landing analysis (FATOLA) computer program, which improved its simulation capabilities, are discussed, and supplemental instructions for use of the program are included. Sample analytical results which illustrate the capabilities of an added nosewheel steering option indicate consistent behavior of the airplane tracking, attitude, motions, and loads for the landing cases and steering situations which were investigated

A mathematical model of an active control landing gear for load control during impact and roll-out

A mathematical model of an active control landing gear (ACOLAG) was developed and programmed for operation on a digital computer. The mathematical model includes theoretical subsonic aerodynamics; first-mode wing bending and torsional characteristics; oleo-pneumatic shock strut with fit and binding friction; closed-loop, series-hydraulic control; empirical tire force-deflection characteristics; antiskid braking; and sinusoidal or random runway roughness. The mathematical model was used to compute the loads and motions for a simulated vertical drop test and a simulated landing impact of a conventional (passive) main landing gear designed for a 2268-kg (5000-lbm) class airplane. Computations were also made for a simply modified version of the passive gear including a series-hydraulic active control system. Comparison of computed results for the passive gear with experimental data shows that the active control landing gear analysis is valid for predicting the loads and motions of an airplane during a symmetrical landing. Computed results for the series-hydraulic active control in conjunction with the simply modified passive gear show that 20- to 30-percent reductions in wing force, relative to those occurring with the modified passive gear, can be obtained during the impact phase of the landing. These reductions in wing force could result in substantial increases in fatigue life of the structure

Analytical investigation of the landing dynamics of a large airplane with a load-control system in the main landing gear

The results of an evaluation of an active load-control landing gear computer program (ACOLAG) for predicting the landing dynamics of airplanes with passive and active main gears are presented. ACOLAG was used in an analytical investigation of the landing dynamics of a large airplane with both passive and active main gears. It was concluded that the program is valid for predicting the landing dynamics of airplanes with both passive and active main gears. It was shown that the active gear reduces airframe-gear forces and airplane motions following initial impact, and has the potential for significant reductions in structural fatigue damage relative to that which occurs with the passive gear

Field Wave Gaging Program, Wave Data Analysis Standard.

Source: https://erdc-library.erdc.dren.mil/jspui/This version of the Field Wave Gaging Program (FWGP) Wave Data Analysis Standard focuses on procedures for analyzing directional wave data from pressure slope arrays and pressure/biaxial current meter gages. Nondirectional wave data analysis is inherently included as a simplification (a subset) of directional wave data analysis. Likewise, analysis of data from wave staffs is a subset of these procedures, obtained by eliminating the pressure response correction. The data collection and analysis procedures described are only applicable to wind-generated surface gravity waves of engineering significance. This document covers analysis procedures for measured time series (wave records) that are assumed to contain no significant number of errors or gaps

Examination of Older Driver Steering Adaptation on a High Performance Driving Simulator

The objective of this study was to examine how long it takes for older drivers to adapt their steering control on a fixed-base driving simulator. We hypothesized that older drivers achieve maximum training benefit within the first few minutes of a driving simulation. Thirteen drivers over 65 years of age drove a four-channel, 150º forward field-ofview, 50º rear field-of-view, fixed-base driving simulator for 25 minutes. We used a six-degree steering wheel reversal criterion to evaluate drivers’ adaptation to the simulator. Since drivers’ adapt to a simulator over time, we examined the number of steering wheel reversals greater than six degrees that occurred per minute during each of three sections, the start, middle and end of the 25-minute drive. The results showed that older drivers needed about three minutes to adapt and get the “feel” of the simulator. Before this time driving behavior in the simulator may not be representative of actual driving performance. These results provide preliminary support for assuming that an adaptation period as short as five minutes may enable drivers to adapt to the driving simulator and drive normally

Chromosome Organization in Meiosis

Our objective is to understand the mechanics of homologous chromosome pairing during meiosis. Aberrant pairing can result in nondisjunction and birth defects in humans. This study used yeast, Saccharomyces cerevisiae, with chromosomally‐integrated arrays of tetO operators that bind TetR repressor proteins fused to GFP to produce a fluorescent signal. In diploid cells, the tetO/TetR‐GFP system allows homologous chromosomes to be identified as two foci (unpaired) or one focus (paired) as they progress through meiosis. We conducted three replicate timecourse experiments, analysing three different stages of meiosis, t=0 hours: pre‐meiotic, t=3 hours: pairing transition, and t=5 hours: synapsis. At each stage, the cells were imaged for 25 minutes, with z‐stacks taken at 30 second intervals. To analyse individual cells, we developed a 4D image analysis pipeline in MATLAB that allowed us to calculate the mean squared change in distance (MSCD), a metric describing the distance between two foci, and analyse deviations from normal diffusive motion