Mars: Morphology of Southern Hemisphere intracrater dunefields

Viking Orbiter images of intracrater dunefields in the Noachis Terra region were examined in order to study the morphology of these landforms and to assess their relationship to local geological settings. The sizes of the dunefields range from 40 to 3600 sq km and vary directly with crater size. Preliminary studies reveal dunefields of two varieties. The most common type is composed of massed straight to slightly wavy crescentic dunes similar to those described by Breed. Dunefields of this type occupy more than 20% of the area of the crater floor, with the dunefield margins often marked by a large dune wall or rampart. Dune spacing ranges between 0.7 and 1.2 km. The second type of dune accumulation consists of clusters of large, widely spaced straight or curved ridges, which often intersect to create rectilinear patterns. Dunes are typically spaced 1.6 to 4 km apart. Earth terrestrial analogs for these dunes are discussed

A simulation for gravity fine structure recovery from high-low GRAVSAT SST data

Covariance error analysis techniques were applied to investigate estimation strategies for the high-low SST mission for accurate local recovery of gravitational fine structure, considering the aliasing effects of unsolved for parameters. Surface density blocks of 5 deg x 5 deg and 2 1/2 deg x 2 1/2 deg resolution were utilized to represent the high order geopotential with the drag-free GRAVSAT configured in a nearly circular polar orbit at 250 km. altitude. GEOPAUSE and geosynchronous satellites were considered as high relay spacecraft. It is demonstrated that knowledge of gravitational fine structure can be significantly improved at 5 deg x 5 deg resolution using SST data from a high-low configuration with reasonably accurate orbits for the low GRAVSAT. The gravity fine structure recoverability of the high-low SST mission is compared with the low-low configuration and shown to be superior

Two-point Taylor series expansions

Coefficients calculated for Taylor series expansion about two points - application of Taylor expansion to two-body proble

Optimized computation with recursive power series integration

Optimized computation with recursive power series integration, applied to three body proble

Micromachined Millimetre-Wave Passive Components at 38 and 77 GHz

A precision micro-fabrication technique has been developed for millimetre-wave components of air-filled three-dimensional structures, such as rectangular coaxial lines or waveguides. The devices are formed by bonding several layers of micromachining defined slices with a thickness of a few hundred micrometres. The slices are thickphotoresist SU8 defined by photolithography, or silicon with a pattern defined by deep reactive ion etching; both are coated with gold by evaporation. The process is simple, and low-cost, as compared with conventional precision metal machining, but yields mm-wave components with good performance. The components are light weight and truly airfilled with no dielectric support. This paper reviews several of these micromachined mm-wave components at 38 and 77 GHz for communications and radar applications

A novel, easy-to-clean protein shaker

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (p. 24).The goal on this thesis project was to develop a novel, easy-clean protein shaker. Protein shakers are used to contain and mix protein supplementation powder and water or liquid of the user's choice. Due to the nature of products within the fitness theme, shakers should be easy to use and low maintenance. Significant problems with current protein shakers are bacteria build-up in hard-to-reach places, low quality seals, mouthpiece caps separating from the shaker, and unsatisfactory mixing. Therefore, the goal of this project was to design and prototype a protein shaker that would be easy to clean, preventing unnecessary bacteria build-up in hard-to-reach locations in the shaker. In order to identify the needs of shaker users, an investigation into what current shaker users believed important in a product was conducted. A new design that eliminated all corners and crevasses was proposed and a prototype was constructed using rapid prototyping technology. The prototype provided further insight to additional improvements that could be made to the design. The goal of being easy to clean was successfully achieved.by Donald R. Lancaster.S.B