Premission and postmission simulation studies of the foot-controlled maneuvering unit for Skylab experiment T-020

A Skylab experiment was conducted to study the maneuvering capabilities of astronauts using a relatively simple self-locomotive device, referred to as the foot-controlled maneuvering unit, and to evaluate the effectiveness of ground-based facilities simulating the operation of this device in weightless conditions of space. Some of the special considerations given in the definition and development of the experiment as related to the two ground-based simulators are reviewed. These simulators were used to train the test subjects and to obtain baseline data which could be used for comparison with the in-flight tests that were performed inside the Skylab orbital workshop. The results of both premission and postmission tests are discussed, and subjective comparisons of the in-flight and ground-based test conditions are presented

The foot-controlled maneuvering unit: Summary report on Skylab experiment T-020

Skylab experiment T-020 was conducted to study the maneuvering capabilities of astronauts using a relatively simple experimental self-locomotive device, referred to as the foot-controlled maneuvering unit, and to evaluate the effectiveness of ground-based facilities simulating the operation of this device in weightless conditions of space. The final results as presented of this experiment which includes comparison of the tests performed during missions SL-3 and SL-4 of the Skylab with those performed on the simulators. Some of the results of this experiment and those of Skylab experiment M509, which employed an experimental hard-controlled maneuvering unit, are discussed in terms of the development of a possible future operational maneuvering system

Recombination Methods for Jets in p\pbar Collisions

A jet algorithm must specify how to (re-)combine different partons or towers into a single four-vector. Various recombination schemes have been used experimentally to examine the transverse energy profile of jets in hadron colliders. Generally, the data is insensitive to which scheme is used. However, we argue that the recombination scheme previously used by the \DO\ collaboration is expected to have large perturbative corrections and should not be used for the purposes of making a quantitative comparison with fixed-order perturbation theory.Comment: 11 pages in PLAIN TeX with 4 uuencoded figures embedded with epsf.te

QCD Calculations by Numerical Integration

Calculations of observables in Quantum Chromodynamics are typically performed using a method that combines numerical integrations over the momenta of final state particles with analytical integrations over the momenta of virtual particles. I discuss a method for performing all of the integrations numerically.Comment: 9 pages including 2 figures. RevTe

Progress towards 2 to 2 scattering at two-loops

We discuss the two-loop integrals necessary for evaluating massless 2 to 2 scattering amplitudes. As a test process, we consider the leading colour two-loop contribution to qqbar to q'qbar'. We show that for physical scattering processes the two Smirnov-Veretin planar box graphs I1 and I2 are accompanied by factors of 1/(D-4) thereby necessitating a knowledge of both I1 and I2 to O(epsilon). Using an alternative basis I1 and the irreducible numerator integral I3, the factors of 1/(D-4) disappear.Comment: 6 pages, latex, npb.sty, 3 postscript figures, contributed to proceedings of "Loops and Legs in Quantum Field Theory", Bastei, Germany, April 9-14, 200