A study was performed to evaluate the performance of equivalent drag area single parachute systems and cluster parachute systems during the early inflation and initial deceleration phase. Analytical work showed that the cluster system could exhibit better performance during this unsteady aerodynamic phase due to a significant decrease in the apparent mass of air influenced by the parachutes. Two test programs have been performed in support of these assumptions. The first compared systems with parachute drag areas of approximately 750 ft/sup 2/ and a payload of 2400 lbs. The cluster system exhibited increased performance and less susceptibility to parachute collapse due to wake recontact. The second series compared systems with parachute drag areas of approximately 260 ft/sup 2/ with a payload of 800 lbs. The advantages of the cluster system were less apparent but performance was moderately improved. 4 refs., 7 figs.
The activities involved in establishing an integrated CIM database at Sandia National Laboratories (SNL) are centered around the development of information engineering techniques. Several information engineering techniques were investigated including: top-down/bottom-up, data flow, entity-attribute and binary models. Most of the techniques were rejected because they did not capture all of the required information or they captured information that was not needed in the development of the CIM database. All current modeling activity is required for database development. This paper describes the modeling methodology utilized, the information engineering practices being developed, and a distributed database implementation at SNL. 10 refs., 12 figs.
This paper describes the migration path a company goes through as it moves up the data management learning curve. This migration path is based on four distinct roles for data management in CIM. The first two sections review the justification for CIM and data management. The first section describes the changing competitive environment manufacturers face and how CIM addresses the problems this situation creates. The second section identifies the two key characteristics of a database management system and the benefits provided. The third section identifies and discusses the four roles for data management in CIM. These four roles and their variations provide snapshots of where a company is on the data management learning curve. The fourth section describes the migration path a company goes through as it moves up the learning curve. Although there are similarities, there are some significant differences between this learning curve and the one experienced by MIS as it adopted data management technology. 3 refs.
The fire risk scoping study was sponsored by the US Nuclear Regulatory Commission and performed at Sandia National Laboratories. The study was initiated as a result of previous USNRC-sponsored fire research efforts that had identified certain fire risk issues that had not been addressed in previously completed commercial nuclear power plant fire risk analyses. The specific objectives of this study were: (1) to review and requantify fire risk scenarios from four fire probabilistic risk assessments in light of updated data bases made available as a result of USNRC-sponsored Fire Protection Research Program and updated computer fire modeling capabilities, (2) to identify potentially significant fire risk issues that have not been previously addressed in a fire risk context and to quantify the potential impact of those identified fire risk issues where possible, and (3) to review current fire regulations and plant implementation practices for relevance to the identified unaddressed fire risk issues. 9 refs., 3 tabs.
The Simplified Analytical Model of Penetration with Lateral Loading (SAMPLL) computer code developed at Sandia National Laboratories has been modified to allow additional penetration capabilities. The new capabilities include the ability to model penetration by other than cylindrical penetrators (flares, tapers, and boattails) and the ability to calculate penetration/perforation of multiple layers of different materials. Additionally, updated soil and rock empirical equations have been added to the model. A broader range of problems can now be modeled more accurately with the modified SAMPLL. 7 refs., 6 figs.
Article VII, paragraphs 8 and 14, of the inspection protocol of the INF Treaty between the US and the USSR provides for the use of radiation detection devices as a verification tool. That is, the Treaty allows the parties to measure the radiation from the radioactive components of nuclear weapons in order to verify that the inspected party is complying with the Treaty. This is the only verification provision in the Treaty that addresses the nuclear components of the relevant weapon systems. Acceptance of and confidence in such measurements is a significant development and similar measurements may be needed for verification of future treaties.
Semiconductor detectors for high energy physics applications offer the potential to obtain accurate particle spacial resolution and on-line data reduction. A significant disadvantage of semiconductor detectors and their associated circuitry however, is their sensitivity to radiation. Fortunately, a sufficient understanding of radiation effects on semiconductor devices exists that some classes of radiation tolerant semiconductor detectors are possible. 11 refs., 11 figs.
The Design Assistance Center (DAC) has developed a database of design, performance, and operating experience for remote photovoltaic (PV) systems. The DAC uses this database to assist potential users in evaluating PV for their specific applications and to accelerate the acceptance of PV as a viable power option for remote applications. 12 refs., 1 fig., 1 tab.
Strong coupling models for the electronic structure of La{sub 2}CuO{sub 4} are derived in two successive stages of renormalization. First, a three-band Hubbard model is derived using a constrained density functional approach. Second, exact diagonalization studies of finite clusters within the three band Hubbard model are used to select and map the low energy spectra onto effective one-band Hamiltonians. At each stage, some observables are calculated and found to be in quantitative agreement with experiment. The final results suggest the following models to be adequate descriptions of the low energy scale dynamics: (1) a spin 1/2 Heisenberg model for the insulating case with nearest neighbor J{approx}130 meV; (2) a t -- t' -- J'' model with nearly identical parameters for the electron and hole doped cases. 14 refs., 2 figs., 1 tab.
A high intensity acoustic test facility has been designed and is under construction at Sandia National Laboratories in Albuquerque, NM. The chamber is designed to provide an acoustic environment of 154dB (re 20 {mu}Pa) overall sound pressure level over the bandwidth of 50 Hz to 10,000 Hz. The chamber has a volume of 16,000 cubic feet with interior dimensions of 21.6 ft {times} 24.6 ft {times} 30 ft. The construction of the chamber should be complete by the summer of 1990. This paper discusses the design goals and constraints of the facility. The construction characteristics are discussed in detail, as are the acoustic performance design characteristics. The authors hope that this work will help others in designing acoustic chambers. 12 refs., 6 figs.
We have recently developed a new theoretical approach to the study of polymer liquids. The theory is based on the reference interaction site model'' (RISM theory) of Chandler and Andersen, which has been successful in describing the structure of small molecule liquids. We have recently extended our polymer RISM theory to the case of polymer blends. In the present investigation we have applied this theory to two special binary blends: (1) the athermal mixture where we isolate structural effects, and (2) the isotopic mixture in which structurally identical polymer chains interact with dissimilar attractive interactions. By studying these two special cases we are able to obtain insights into the molecular factors which control the miscibility in polymer mixtures. 18 refs., 2 figs.
A refrigerated Dewar has been used successfully with the Josephson array voltage calibration system. It has been used to re-liquefy helium with no degradation of the calibration system's performance. The independence of the array voltage from temperature has been confirmed to three parts in 10{sup 8} per Kelvin using this Dewar. 6 refs., 3 figs.
A nuclear waste management system presents a challenge to organize a development program that can effectively achieve the goal of providing timely solutions to the problem of nuclear waste management. A few distinguishing factors can serve to aid the establishment of an effective program.
A new technique for tunnel detection and location has recently been theoretically modeled and experimentally demonstrated. The objective of this research is to develop a general method for remotely detecting the presence of unauthorized tunneling activities using one or more boreholes and a surface source. A line current or dipole-dipole array, positioned on or near the surface of the earth, is used as the TE current source. Subsurface electric and magnetic field measurements are made in a borehole that is situated near a suspected tunnel location. The presence of a tunnel causes subsurface scattering of the field components created by the source. Both the electric and magnetic field strength and phase data is perturbed by the presence of a nearby tunnel. The scattered fields are observed on both sides of the tunnel relative to the source position. 1 fig.
This talk was given at the 14th International Pyrotechnic Seminar on September 21, 1989, in Jersey, United Kingdom, as one of two plenary lectures. It briefly surveys the current technology of pyrotechnic devices and examines trends for the future. The pyrotechnic'' can have several meanings. In this talk, pyrotechnic devices'' are devices in which porous materials undergo reduction-oxidation reactions and produce useful products. The pyrotechnic materials are generally fuel-oxidizer systems without binders, in contrast to primary or secondary explosives or propellants. The word pyrotechnic'' is often used to include explosive, squib, propellant, or other ordnance type devices, especially in the European community. The major need for pyrotechnic devices has always been military and defense; however, as technology advances, the civilian uses of pyrotechnics will continue to grow. If every automobile had a pyrotechnic device to trigger its air or crash bag, that application alone would mean millions of devices per year. Applications in safety, fire fighting, law enforcement, and other commercial applications are likely to increase due to the increased capability of pyrotechnic devices and the integration of such devices in system designs. 2 refs., 56 figs.
Computed torque algorithms are used to compensate for the changing dynamics of robot manipulators in order to ensure that a constant level of damping is maintained for all configurations. Unfortunately, there are three significant problems with existing computed torque algorithms. First, they are nonpassive and can lead to unstable behavior; second, they make inefficient use of actuator capability; and third, they cannot be used to maintain a constant end-effector stiffness for force control tasks. Recently, we introduced a new control algorithm for robots which, like computed torque, uses a model of the manipulator's dynamics to maintain a constant level of damping in the system, but does so passively. This new class of passive control algorithms has guaranteed stability properties, utilizes actuators more effectively, and can also be used to maintain constant end-effector stiffness. In this paper, this approach is described in detail, implementation issues are discussed, and simulation results are given. 15 refs., 6 figs., 2 tabs.
We have performed nanosecond-resolution measurements of the lateral electrical resistivity of thin metal films on insulating substrates. Comparison of transient resistivity measurements with optical reflectivity measurements and heat-flow calculations permits the determination of the position and velocity of a planar crystal/melt in interface, and an estimate of undercooling during pulsed laser melting of metals. We report detailed results for rapid solidification of Ni, including the observation of hypercooling of liquid Ni. 14 refs., 3 figs., 1 tab.
Ohwa, M.; Kushner, M.J.; Peters, P.J.; Patterson, E.L.; Brannon, P.J.
E-beam excitation of the atomic xenon laser is theoretically and experimentally investigated using short-pulse high-power deposition (>MW/cm{sup 3}-atm) and low-power high-energy loading ({le}1 kJ/{ell}-atm). Scaling laws are derived to maximize laser power and energy efficiency. 4 refs.
An object-oriented Robot Independent Programming Environment (RIPE) developed at Sandia National Laboratories is being used for rapid design and implementation of a variety of applications. A system architecture based on hierarchies of distributed multiprocessors provides the computing platform for a layered programming structure that models the application as a set of software objects. These objects are designed to support model-based automated planning and programming, real-time sensor-based activity, error handling, and robust communication. The object-oriented paradigm provides mechanisms such as inheritance and polymorphism which allow the implementation of the system to satisfy the goals of software reusability, extensibility, reliability, and portability. By designing a hierarchy of generic parent classes and device-specific subclasses which inherit the same interface, a Robot Independent Programming Language (RIPL) is realized. Work cell tasks demonstrating robotic cask handling operations for nuclear waste facilities are successfully implemented using this object-oriented software environment. 22 refs., 8 figs.
An adaptive, swing-free trajetory planner for a gantry robot has been analytically developed and experimentally implemented on a commercial robot. A batch, nonlinear least square estimator (differential correction) is used to predict the initial conditions, mass, and frequency of the simply suspended object from a set of force sensor measurements. These parameters, in turn, are supplied to the swing-free trajectory planner to perform the maneuver. These algorithms have been implemented on a CIMCORP XR6100 gantry robot, and swing-free trajectories have been performed by the robot using the adaptive trajectory planner.
Angularly accelerating a cantilevered rod which sags under gravity couples the out-of-plane dynamics of the flexible rod and causes oscillation in both the horizontal and vertical planes. A parameter-scheduled trajectory planner has been analytically developed and experimentally implemented on a commercial robot to suppress the first mode of these vibrations during a horizontal angular move. A load was attached to the tip of the rod and the resulting static, out-of-plane, hub torque was measured with a force-torque sensor. This torque was used to predict the period of the horizontal first mode of vibration of the payload (rod and attached load) from a nonlinear function in order to calculate (schedule) the appropriate control parameters for the angular move. This system has been implemented on a Cincinnati Milacron T3-786 robot, and vibration suppressed trajectories (which reduce the coupled residual vibrations by over 90%) have been performed by the robot for various payloads. 9 refs., 3 figs., 2 tabs.
Accurate motion control of wheeled mobile robots (WMRs) is required for their application to autonomous, semi-autonomous and teleoperated tasks. The similarities between WMRs and stationary manipulators suggest that current, successful, model-based manipulator control algorithms may be applied to WMRs. Special characteristics of WMRs including higher-pairs, closed-chains, friction and unactuated and unsensed joints require innovative modeling methodologies. The WMR modeling challenge has been recently overcome, thus enabling the application of manipulator control algorithms to WMRs. This realization lays the foundation for significant technology transfer from manipulator control to WMR control. We apply two Cartesian-space manipulator control algorithms: resolved motion rate (kinematics-based) and resolved acceleration (dynamics-based) control to WMR servo-control. We evaluate simulation studies of two exemplary WMRs: Uranus (a three degree-of-freedom WMR constructed at Carnegie Mellon University), and Bicsun-Bicas (a two degree-of-freedom WMR being constructed at Sandia National Laboratories) under the control of these algorithms. Although resolved motion rate servo-control is adequate for the control of Uranus, resolved acceleration servo-control is required for the control of the mechanically simpler Bicsun-Bicas because it exhibits more dynamic coupling and nonlinearities. Successful accurate motion control of these WMRs in simulation is driving current experimental research studies. 18 refs., 7 figs., 5 tabs.
Detailed models and analytical procedures are applied to the many complex aspects of spent fuel in transport including characterization of the fuel's irradiation conditions and initial states at the time of shipment, determination of the dynamic forces on the fuel assemblies that result from regulatory transportation accidents, modeling and analysis of the fuel's mechanical response to these forces, and estimation of the releasable radioactivity in the event of cladding breach. The methodology adopts a combined deterministic/probabilistic analysis approach in which each aspect of the problem is appropriately treated on the basis of its level of determinability. The results are obtained in the form of failure probabilities for each regulatory event considered. 3 refs., 6 figs.
This reference consists of a video cassette demonstration of the Fire Ant. This video is 5 minutes in duration and effectively demonstrates the usefulness of the remote controlled Fire Ant.
Welcome to the Connector Selection Program. Users of all experience levels can operate the connector selection program. Its simple design, intuitive operation, and on-line Help facility make the program easy to learn and easy to use. In the hands of an engineer, it is a powerful and flexible tool. The connector selection program was developed by the Interconnections division to help component engineers and systems engineers select connectors as quickly and as easily as possible. The connector selection program is a computer database application that currently includes all the connectors listed in the 1984 MC/SA Special Design Connector Catalog which are available for new design. This list is being expanded to include connectors developed between September 1984 and present. The connector selection program is a very versatile product. It lets you perform a wide spectrum of practical connector searches and provides you with a vast amount of valuable information about each connector found. This manual discusses the use of this program.