A study of the cornering forces generated by aircraft tires on a tilted, free-swiveling nose gear

An experimental investigation was conducted to study the effect of various parameters on the cornering forces produced by a rolling aircraft tire installed on a tilted, free-swiveling nose gear. The parameters studied included tilt angle, trial, tire inflation pressure, rake angle, vertical load, and whether or not a twin tire configuration corotates. These parameters were evaluated by measuring the cornering force produced by an aircraft tire installed on the nose gear of a modified vehicle as it was towed slowly. Cornering force coefficient increased with increasing tilt angle. Increasing trial or rake angle decreased the magnitude of the cornering force coefficient. Tire inflation pressure had no effect on the cornering force coefficient. Increasing vertical load decreased the cornering force coefficient. When the tires of a twin tire system rotated independently, the cornering force coefficients were the same as those for the single-tire configuration. When the twin tire system was made to corotate, however, the cornering force coefficients increased significantly

Measurements of Flow Rate and Trajectory of Aircraft Tire-Generated Water Spray

An experimental investigation was conducted at the NASA Langley Research Center to measure the flow rate and trajectory of water spray generated by an aircraft tire operating on a flooded runway. Tests were conducted in the Hydrodynamics Research Facility and made use of a partial airframe and a nose tire from a general aviation aircraft. Nose tires from a commercial transport aircraft were also used. The effects of forward speed, tire load, and water depth on water spray patterns were evaluated by measuring the amount and location of water captured by an array of tubes mounted behind the test tire. Water ejected from the side of the tire footprint had the most significant potential for ingestion into engine inlets. A lateral wake created on the water surface by the rolling tire can dominate the shape of the spray pattern as the distance aft of the tire is increased. Forward speed increased flow rates and moved the spray pattern inboard. Increased tire load caused the spray to become less dense. Near the tire, increased water depths caused flow rates to increase. Tests using a fuselage and partial wing along with the nose gear showed that for certain configurations, wing aerodynamics can cause a concentration of spray above the wing

Variations in the richness of children's interests and experiences in literature.

Thesis (Ed.M.)--Boston Universit

Freeman v. Pitts: A Rethinking of Public School Desegregation

On March 31, 1992, the United States Supreme Court unanimously declared that federal district courts have the authority to relinquish supervision and control of a public school desegregation plan in incremental stages, before full compliance has been achieved in every area of school operations. The Court also held that public school districts have no duty to remedy racial imbalance caused by demographic shifts once the vestiges of de jure segregation have been eliminated. Reversing a lower court\u27s ruling, Justice Kennedy, writing for the majority, stated that the decision was consistent with the Court\u27s duties to both remedy constitutional violations and to restore control of a public school system to state and local authorities. The Supreme Court\u27s ruling in Freeman v. Pitts may well have whittled away much of the high ground that has been gained in the area of public school desegregation

Synthesis of Compounds Related to Fluoranthene

Part 1a. The known 4-methylfluoranthene and 4-phenylfluoranthene have been synthesised by condensation of methyl and phenyl vinyl ketones, or the corresponding Mannich bases, methyl 2-morpholinoethyl ketone and 2-diethylaminoethyl phenyl ketone respectively, with methyl fluorene-9-carboxylate, followed by hydrolysis and decarboxylation, reduction, cyclisation, and dehydrogenation. Unsuccessful attempts to evolve a new synthesis of methyl fluorene-9-carboxylate were made. Part lb. 1:2:5:6-Dibenzpyracylene was synthesised by a crossed Ullmann reaction between 4-iodofluoranthene and 2-bromonitrobenzene, followed by reduction, diazotisation, and ring-closure. An attempt at synthesis by the method described in Part la failed. The ultra-violet absorption spectrum is reported and discussed, especially in relation to Clar's Anellation Theory. Part 2. 2:3-Benzfluoranthene has been synthesised from o-diphenylenephthalide by Clar's zinc dust-zinc chloride fusion method. An attempt to synthesise 2:3-benzfluoranthene by cyclisation of 9-bromo-9-o-bromo-o-tolylfluorene gave a compound believed, in the light of spectrographic and analytical evidence, to be 1:9-diphenylanthracene. The spectrum of 2:3-benzfluoranthene is reported and discussed, especially in relation to the Anellation Theory. Part 3. 3:4-Dimethylfluoranthene was obtained by the Grignard reaction on 4-keto-3-methyl-1:2:3:4-tetra-hydrofluoranthene, followed by dehydration-dehydrogenation. 2-Methoxyfluoranthene was synthesised by a crossed Ullmann reaction between 1-iodo-2-methoxynaphthalene and o-bromonitrobenzene, followed by reduction, diazotisation, and ring-closure. Part 4. The ultra-violet absorption spectra of several mono-, di-, and trimethylfluoranthenes, methoxy-fluoranthenes, and 4-phenylfluoranthene, not previously recorded, have been measured. They are shown to be of value in characterisation of the pure compounds. Distortion due to overlapping of the substituent methyl- or methoxyl- group with a hydrogen atom in the 2- or 10- substituted derivatives appears to produce corresponding distortions in the ultraviolet absorption curve

Service evaluation of weight outcomes as a function of initial BMI in 34,271 adults referred to a primary care/commercial weight management partnership scheme

Peer reviewedPublisher PD

Tests of highly loaded skids on a concrete runway

Skids have been used at various times for aircraft landing gear ever since the Wright Flyer appeared in the early 1900's. Typically, skids have been employed as aircraft landing gear either at low speeds or at low bearing pressures. Tests were conducted to examine the friction and wear characteristics of various metals sliding on a rough, grooved concrete runway. The metals represented potential materials for an overload protection skid for the Space Shuttle orbiter. Data from tests of six skid specimens conducted at higher speeds and bearing pressures than those of previous tests in the open literature are presented. Skids constructed of tungsten with embedded carbide chips exhibited the lowest wear, whereas a skid constructed of Inconel 718 exhibited high wear rates. Friction coefficients for all the skid specimens were moderate and would provide adequate stopping performance on a long runway. Because of its low wear rate, a skid constructed of tungsten with embedded carbide chips is considered to be a likely candidate for an aircraft skid or overload protection skid

Lunar Surface Potential Changes Possible Associated with Traversals of the Bow Shock

We report an analysis of seven Apollo 14 Apollo Lunar Surface Experiments Package (ALSEP) Suprathermal Ion Detector Experiment (SIDE) "resonance" events from January 1972 through January 1973. The events appear to be associated with traversals of the Moon through the terrestrial bow shock

Cystatins as calpain inhibitors: Engineered chicken cystatin- and stefin B-kininogen domain 2 hybrids support a cystatin-like mode of interaction with the catalytic subunit of μ-calpain

Within the cystatin superfamily, only kininogen domain 2 (KD2) is able to inhibit μ- and m-calpain. In an attempt to elucidate the structural requirements of cystatins for calpain inhibition, we constructed recombinant hybrids of human stefin B (an intracellular family 1 cystatin) with KD2 and Delta L110 deletion mutants of chicken cystatin-KD2 hybrids. Substitution of the N-terminal contact region of stefin B by the corresponding KD2 sequence resulted in a calpain inhibitor of K-i = 188 nM. Deletion of L110, which forms a beta -bulge in family 1 and 2 cystatins but is lacking in KD2, improved inhibition of mu -calpain 4- to 8-fold. All engineered cystatins were temporary inhibitors of calpain due to slow substrate-like cleavage of a single peptide bond corresponding to Gly9-Ala10 in chicken cystatin. Biomolecular interaction analysis revealed that, unlike calpastatin, the cystatin-type inhibitors do not bind to the calmodulin-like domain of the small subunit of calpain, and their interaction with the mu -calpain heterodimer is completely prevented by a synthetic peptide comprising subdomain B of calpastatin domain 1. Based on these results we propose that (i) cystatin-type calpain inhibitors interact with the active site of the catalytic domain of calpain in a similar cystatin-like mode as with papain and (ii) the potential for calpain inhibition is due to specific subsites within the papain-binding regions of the general cystatin fold