Failure of Harmonic Gears During Verification of a Two-Axis Gimbal for the Mars Reconnaissance Orbiter Spacecraft

The Mars Reconnaissance Orbiter (MRO) spacecraft has three two-axis gimbal assemblies that support and move the High Gain Antenna and two solar array wings. The gimbal assemblies are required to move almost continuously throughout the mission's seven-year lifetime, requiring a large number of output revolutions for each actuator in the gimbal assemblies. The actuator for each of the six axes consists of a two-phase brushless dc motor with a direct drive to the wave generator of a size-32 cup-type harmonic gear. During life testing of an actuator assembly, the harmonic gear teeth failed completely, leaving the size-32 harmonic gear with a maximum output torque capability less than 10% of its design capability. The investigation that followed the failure revealed limitations of the heritage material choices that were made for the harmonic gear components that had passed similar life requirements on several previous programs. Additionally, the methods used to increase the stiffness of a standard harmonic gear component set, while accepted practice for harmonic gears, is limited in its range. The stiffness of harmonic gear assemblies can be increased up to a maximum stiffness point that, if exceeded, compromises the reliability of the gear components for long life applications

Personality Type and Job Satisfaction in the Home Office Environment

Human Environmental Science

Assessment of the potential contribution of the Coega industrial development initiative to the Eastern Cape Economy

The research problem addressed in this study was to analyse and report on the development of the Coega Industrial Development Zone as an infrastructure for renewed entrepreneurial activity and profitable management of existing firms in the Eastern Cape. To achieve this objective, a literature study was undertaken to assess the potential benefits achieved at similar industrial development zones around the world and what could be learnt from these developments which will make the Coega Industrial Development Zone workable. The Empirical results obtained, indicate that most local companies are confident that the Coega industrial Development Zone will be beneficial to the region. In conclusion, various recommendations have been made with regard to the findings ascertained in the Empirical Study

Astronomy below the survey threshold in the SKA era

Astronomy at or below the 'survey threshold' has expanded significantly since the publication of the original 'Science with the Square Kilometer Array' in 1999 and its update in 2004. The techniques in this regime may be broadly (but far from exclusively) defined as 'confusion' or 'P(D)' analyses (analyses of one-point statistics), and 'stacking', accounting for the flux-density distribution of noise-limited images co-added at the positions of objects detected/isolated in a different waveband. Here we discuss the relevant issues, present some examples of recent analyses, and consider some of the consequences for the design and use of surveys with the SKA and its pathfinders

The Pine Needle, Fall 1948

Libraries and archives collect materials from different cultures and time periods to preserve and make available the historical record. As a result, materials such as those presented here may reflect sexist, misogynistic, abusive, racist, or discriminatory attitudes or actions that some may find disturbing, harmful, or difficult to view. Both a humor and literary magazine, The Pine Needle was a University of Maine student-produced periodical that began publication in the fall of 1946, the first post-World War II semester that saw GIs returning to campus. The Needle reflected an edginess and rebellion not found in previous UMaine student publications. While past student publications relied on euphemisms for alcohol and dating on campus, The Needle openly promoted the sexualization of co-eds and the use of drugs, tobacco, and alcohol by students who experienced war. Cover art for this issue is by Donald T. Caswell and depicts a man wearing a letterman\u27s sweater chatting up a smiling co-ed wearing a ball cap. In the background, two largely faceless men wearing suits and exhibit hostile posture that communicates jealousy. Don Caswell (1923-2014), was a native of Limestone, Maine and grew up in Brownsville. He joined the U.S. Navy following high school graduation in 1942. He served as a radio operator aboard ships patrolling the Gulf of Alaska throughout the war. Caswell attended the University of Maine on the G.I. Bill, majoring in Art and History. On campus, he was active in the Officer Training Program and was stationed in Tripoli, North Africa as a U.S. Air Force officer during the Korean War. Caswell served as a Lieutenant Colonel in the Air National Guard

Accelerating Universe from an Evolving Lambda in Higher Dimension

We find exact solutions in five dimensional inhomogeneous matter dominated model with a varying cosmological constant. Adjusting arbitrary constants of integration one can also achieve acceleration in our model. Aside from an initial singularity our spacetime is regular everywhere including the centre of the inhomogeneous distribution. We also study the analogous homogeneous universe in (4+d) dimensions. Here an initially decelerating model is found to give late acceleration in conformity with the current observational demands. We also find that both anisotropy and number of dimensions have a role to play in determining the time of flip, in fact the flip is delayed in multidimensional models. Some astrophysical parameters like the age, luminosity distance etc are also calculated and the influence of extra dimensions is briefly discussed. Interestingly our model yields a larger age of the universe compared to many other quintessential models.Comment: 18 pages, 9 figure