Portable light detection system for the blind

System can be used to detect "ready" light on automatic cooking device, to tell if lights are on for visitors, or to tell whether it is daylight or dark outside. Device is actuated like flashlight. Light impinging on photo cell activates transistor which energizes buzzer to indicate presence of light

Identification of a Novel 81-kDa Component of the Xenopus Origin Recognition Complex

The Xenopus origin recognition complex is essential for chromosomal DNA replication in cell-free extracts. We have immunopurified the Xenopus origin recognition complex with anti-Xorc2 antibodies and analyzed its composition and properties. Xorc2 (p63) is specifically associated with Xorc1 (p115) and up to four additional polypeptides (p81, p78, p45, and p40). The cDNA encoding p81 is highly homologous to various expressed sequence tags from humans and mice encoding a protein of previously unknown function. Immunodepletion of p81 from Xenopus egg extracts, which also results in the removal of Xorc2, completely abolishes chromosomal DNA replication. Thus, p81 appears to play a crucial role at S phase in higher eukaryotes

Ejection Forces and Friction Coefficients from Injection Molding Experiments Using Rapid Tooling Inserts

Experiments have been performed with injection mold inserts made using solid freeform fabrication processes in an effort to further study such applications for economic production of small quantities of parts. Static friction coefficients were determined for HDPE and HIPS against P-20 steel, sintered LaserForm ST-100, and stereolithography SL 5170 using the ASTM D 1894 standard. Injection mold inserts were constructed of the same three materials and were used to inject cylindrical parts using HDPE and HIPS. Ejection forces were measured, and a model was used to calculate ejection forces and apparent coefficients of static friction. Statistical analyses were used to determine the effects of packing time, cooling time and packing pressure on ejection force for the three insert types. This paper compares experimental and calculated ejection forces, compares standard friction test results to calculated apparent coefficients of friction, summarizes the statistical results, and comments on the feasibility of using rapid tooled inserts for injection molding.Mechanical Engineerin

Frictional behavior of talc-calcite mixtures

Faults involving phyllosilicates appear weak when compared to the laboratory-derived strength of most crustal rocks. Among phyllosilicates, talc, with very low friction, is one of the weakest minerals involved in various tectonic settings. As the presence of talc has been recently documented in carbonate faults, we performed laboratory friction experiments to better constrain how various amounts of talc could alter these fault’s frictional properties. We used a biaxial apparatus to systematically shear different mixtures of talc and calcite as powdered gouge at room temperature, normal stresses up to 50 MPa and under different pore fluid saturated conditions, i.e., CaCO3-equilibrated water and silicone oil. We performed slide-hold-slide tests, 1–3000 s, to measure the amount of frictional healing and velocity-stepping tests, 0.1–1000 μm/s, to evaluate frictional stability. We then analyzed microstructures developed during our experiments. Our results show that with the addition of 20% talc the calcite gouge undergoes a 70% reduction in steady state frictional strength, a complete reduction of frictional healing and a transition from velocity-weakening to velocity-strengthening behavior. Microstructural analysis shows that with increasing talc content, deformation mechanisms evolve from distributed cataclastic flow of the granular calcite to localized sliding along talc-rich shear planes, resulting in a fully interconnected network of talc lamellae from 20% talc onward. Our observations indicate that in faults where talc and calcite are present, a low concentration of talc is enough to strongly modify the gouge’s frictional properties and specifically to weaken the fault, reduce its ability to sustain future stress drops, and stabilize slip

A Neural Network Realization of Fuzzy ART

A neural network realization of the fuzzy Adaptive Resonance Theory (ART) algorithm is described. Fuzzy ART is capable of rapid stable learning of recognition categories in response to arbitrary sequences of analog or binary input patterns. Fuzzy ART incorporates computations from fuzzy set theory into the ART 1 neural network, which learns to categorize only binary input patterns, thus enabling the network to learn both analog and binary input patterns. In the neural network realization of fuzzy ART, signal transduction obeys a path capacity rule. Category choice is determined by a combination of bottom-up signals and learned category biases. Top-down signals impose upper bounds on feature node activations.British Petroleum (89-A-1204); Defense Advanced Research Projects Agency (90-0083); National Science Foundation (IRI 90-00530); Office of Naval Research (N00014-91-J-4100); Air Force Office of Scientific Research (90-0175

The influence of normal stress and sliding velocity on the frictional behaviour of calcite at room temperature. Insights from laboratory experiments and microstructural observations

The presence of calcite in and near faults, as the dominant material, cement, or vein fill, indicates that the mechanical behaviour of carbonate-dominated material likely plays an important role in shallow- and mid-crustal faulting. To better understand the behaviour of calcite, under loading conditions relevant to earthquake nucleation, we sheared powdered gouge of Carrara Marble, >98 per cent CaCO3, at constant normal stresses between 1 and 100 MPa under water-saturated conditions at room temperature. We performed slide-hold-slide tests, 1–3000 s, to measure the amount of static frictional strengthening and creep relaxation, and velocity-stepping tests, 0.1–1000 µm s–1, to evaluate frictional stability. We observe that the rates of frictional strengthening and creep relaxation decrease with increasing normal stress and diverge as shear velocity is increased from 1 to 3000 µm s–1 during slide-hold-slide experiments. We also observe complex frictional stability behaviour that depends on both normal stress and shearing velocity. At normal stresses less than 20 MPa, we observe predominantly velocity-neutral friction behaviour. Above 20 MPa, we observe strong velocity-strengthening frictional behaviour at low velocities, which then evolves towards velocity-weakening friction behaviour at high velocities. Microstructural analyses of recovered samples highlight a variety of deformation mechanisms including grain size reduction and localization, folding of calcite grains and fluid-assisted diffusion mass transfer processes promoting the development of calcite nanograins in the highly deformed portions of the experimental fault. Our combined analyses indicate that calcite fault gouge transitions from brittle to semi-brittle behaviour at high normal stress and slow sliding velocities. This transition has important implications for earthquake nucleation and propagation on faults in carbonate-dominated lithologies

A study of mission duration extension problems Summary report, 1 Oct. 1966 - 1 Oct. 1967

Characteristics, constraints, and implications of long duration space missions based on use of available hardware and maintenance/repair actions in spac

A study of an Extended Lunar Orbital Rendezvous /ELOR/ mission. Volume 3 - Summary of results

Optimal system and mission planning for extended lunar orbital rendezvous missio

Laser Interferometer Gravitational-Wave Observatory beam tube component and module leak testing

Laser Interferometer Gravitational-Wave Observatory (LIGO) is a joint project of the California Institute of Technology and the Massachusetts Institute of Technology funded by the National Science Foundation. The project is designed to detect gravitational waves from astrophysical sources such as supernova and black holes. The LIGO project constructed observatories at two sites in the U.S. Each site includes two beam tubes (each 4 km long) joined to form an "L" shape. The beam tube is a 1.25 m diam 304 L stainless steel, ultrahigh vacuum tube that will operate at 1×10^–9 Torr or better. The beam tube was manufactured using a custom spiral weld tube mill from material processed to reduce the outgassing rate in order to minimize pumping costs. The integrity of the beam tube was assured by helium mass spectrometer leak testing each component of the beam tube system prior to installation. Each 2 km long, isolatable beam tube module was then leak tested after completion

Advances in lightning protection that satisfies contemporary standards

Described here are the LEC, Inc. Spline Ball Ionizer (trademark) (SBI) and the Spline Ball Terminal (trademark) (SBT) families and how their use in a conventional lightning protection system can achieve strike prevention in a conventional setting. A properly completed standards based system which is composed of the SBI and SBT in a hybrid system will provide two modes of lightning protection: (1) a stroke prevention mode that reduces the risk of a strike to the protected facility in proportion to the size of that facility and the size and number of SBI/SBT's used; and (2) a Stroke Collector-Diverter System that is far superior to any system now in use because it collects strokes entering the protected area from any direction and angle