Active sub-slab depressurization (SSD) systems are an effective means of reducing indoor radon concentrations in residential buildings. However, energy is required to operate the system fan and to heat or cool the resulting increased building ventilation. We present regional and national estimates of the energy requirements, operating expenses, and CO{sub 2} emissions associated with using SSD systems at saturation (i.e., in all U.S. homes with radon concentrations above the EPA remediation guideline and either basement or slab-on-grade construction). The primary source of uncertainty in these estimates is the impact of the SSD system on house ventilation rate. Overall, individual SSD system operating expenses are highest in the Northeast and Midwest at about $99 y{sup -1}, and lowest in the South and West at about $66 y{sup -1}. The fan consumes, on average, about 40% of the end-use energy used to operate the SSD system and accounts for about 60% of the annual expense. At saturation, regional impacts are largest in the Midwest because this area has a large number of mitigable houses and a relatively high heating load. We estimate that operating SSD systems in U.S. houses where it is both appropriate and possible (about 2.6 million houses), will annually …

We extend the QCD sum rule analysis of the form factor F(sub)(gamma*gamma* -> pi^0)(q(sub)1^2, q(sub)2^2) into the region of small virtuality of one of the photons:

The Albany Research Center is conducting atmospheric corrosion research in coastal environments to improve the performance of materials in the Nation's infrastructure. The corrosion of bare metals, and of painted, thermal-sprayed, and galvanized steels are presented for one-year exposures at sites located on bridges and utility poles along the Oregon coast. The effects of microclimates (for example distance from the ocean, high wind zones, and salt-fog prone regions) are examined in conjunction with sample orientation and sheltered/unsheltered comparisons. An atmospheric corrosion model examines the growth and dissolution of corrosion product layers to arrive at a steady-state thickness and corrosion rate.

Tensile creep-rupture of a commercial gas pressure sintered Si3N4 and a sintered SiC is examined at 1038, 1150, and 1350 C. These 2 ceramics are candidates for nozzles and combustor tiles that are to be retrofitted in land-based gas turbine engines, and there is interest in their high temperature performance over service times {ge} 10,000 h (14 months). For this long lifetime, a static tensile stress of 300 MPa at 1038/1150 C and 125 Mpa at 1350 C cannot be exceeded for Si3N4; for SiC, the corresponding numbers are 300 Mpa at 1038 C, 250 MPa at 1150 C, and 180 MPa at 1350 C. Creep-stress exponents for Si3N4 are 33, 17, and 8 for 1038, 1150, 1350 C; fatigue- stress exponents are equivalent to creep exponents, suggesting that the fatigue mechanism causing fracture is related to the creep mechanism. Little success was obtained in producing failure in SiC after several decades of time through exposure to appropriate tensile stress; if failure did not occur on loading, then the SiC specimens most often did not creep-rupture. Creep-stress exponents for the SiC were determined to be 57, 27, and 11 for 1038, 1150, and 1350 C. For SiC, the fatigue-stress exponents …

The ability to rapidly command multi-robot behavior is crucial for the acceptance and effective utilization of multiple robot control. To achieve this, a modular- multiple robot control solution is being, pursued using the SMART modular control architecture. This paper investigates the development of a new dual-arm kinematics module (DUAL-KLN) which allows multiple robots, previously controlled as separate stand-alone systems, to be controlled as a coordinated multi-robot system. The DUAL-KIN module maps velocity and force information from a center point of interest on a grasped object to the tool centers of each grasping robot. Three-port network equations are used and mapped into the scattering operator domain in a computationally efficient form. Application examples of the DUAL-KLN module in multi-robot coordinated control are given.

The ambient atmosphere between the laser transmitter and the target can affect CO{sub 2} differential absorption lidar (DIAL) measurement sensitivity through a number of different processes. In this work, we will address two of the sources of atmospheric interference with CO{sub 2} DIAL measurements: effects due to beam propagation through atmospheric turbulence and extinction due to absorption by atmospheric gases. Measurements of atmospheric extinction under different atmospheric conditions are presented and compared to a standard atmospheric transmission model (FASCODE). We have also investigated the effects of atmospheric turbulence on system performance. Measurements of the effective beam size after propagation are compared to model predictions using simultaneous measurements of atmospheric turbulence as input to the model. These results are also discussed in the context of the overall effect of beam propagation through atmospheric turbulence on the sensitivity of DIAL measurements.

A lower extremity model has been developed to study occupant injury mechanisms of the major bones and ligamentous soft tissues resulting from vehicle collisions. The model is based on anatomically correct digitized bone surfaces of the pelvis, femur, patella and the tibia. Many muscles, tendons and ligaments were incrementally added to the basic bone model. We have simulated two types of occupant loading that occur in a crash environment using a non-linear large deformation finite element code. The modeling approach assumed that the leg was passive during its response to the excitation, that is, no active muscular contraction and therefore no active change in limb stiffness. The approach recognized that the most important contributions of the muscles to the lower extremity response are their ability to define and modify the impedance of the limb. When nonlinear material behavior in a component of the leg model was deemed important to response, a nonlinear constitutive model was incorporated. The accuracy of these assumptions can be verified only through a review of analysis results and careful comparison with test data. As currently defined, the model meets the objective for which it was created. Much work remains to be done, both from modeling and …

The authors investigate the apparent enhancement of target strength in the steady-state Tate model of long-rod penetration. They show that computing the effective area over which the target behaves as a fluid provides an explanation of the effective 1-D target strength measured empirically. Expressing the effective target strength as R{sub t} = a {times} Y{sub t}, they postulate that a = A{sub e}/A{sub p}, where Y{sub t} is the nominal strength; A{sub e} is the effective target fluid cross-sectional area and A{sub p} the projectile cross-sectional area. For the case of a rod and projectile of the same material, they use the Tate model together with the jet model of Birkhoff et al. to show a {approx} 4 is likely. Simultaneously satisfying Newton`s Second Law and the Tate model yields a very general derivation of a = 4. By explicitly including strength terms in both the Tate equation and Newton`s Second Law, an even more general a = f(v,{rho}{sub p},{rho}{sub t},Y{sub p},Y{sub t}) can be derived.

One of the principal tools of industrial ecology is life-cycle assessment which intends to improve overall economic efficiency and to minimize negative environmental impacts of products, processes, and facilities. This paper describes a general methodology for environmentally responsible assessment of these activities; it discusses some of the underlying considerations for this assessment which are accessible by rigorous quantitative analysis; and an overall economic performance metric is proposed which puts both environmental and economic considerations on a common basis. Finally, some considerations involved in this approach is introduced as a guide to environmentally sound design and management.

This paper describes an end-use analysis of the national energy requirements of US residential window technologies. The authors estimate that the current US stock of 19 billion square feet of residential windows is responsible for 1.7 quadrillion BTUs (or quads) per year of energy use--1.3 quads of heating and 0.4 quads of cooling energy--which represents about 2% of total US energy consumption. They show that national energy use due to windows could be reduced by 25% by the year 2010 through accelerated adoption of currently available, advanced window technologies such as low-e and solar control low-e coatings, vinyl and wood frames, and superwindows. The authors evaluate the economics of the technologies regionally, considering both climatic and energy price variations, and find that the technologies would be cost effective for most consumers.

In Dec. 1994, IAEA safeguards were initiated on inventory of Pu- bearing materials, originating from the US nuclear weapons complex, at vault 3 of DOE`s Plutonium Finishing Plant at Hanford. Because of the diversity and heterogeneity of the Pu, plant operators have increasingly used calorimetry for accountability measurements. During the recent commencement of IAEA safeguards at vault 3, destructive (electrochemical titration) methods were used to determine Pu concentrations in subsamples of inventory items with widely ranging chemical purities. The Pu concentrations in the subsamples were determined and contribution of heterogeneity to total variability was identified. Measurement results, gathered by PFP and IAEA laboratories, showed total measurement variability for calorimetry to be comparable with or lower than those of sampling and chemical analyses.

This paper presents a new technique for representing multivalued data sets defined on an integer lattice. It extends the state-of-the-art in volume rendering to include nonhomogeneous volume representations. That is, volume rendering of materials with very fine detail (e.g. translucent granite) within a voxel. Multivariate volume rendering is achieved by introducing controlled amounts of noise within the volume representation. Varying the local amount of noise within the volume is used to represent a separate scalar variable. The technique can also be used in image synthesis to create more realistic clouds and fog.

Unique shock compression experiments have been developed and pursued which provide material equation of state data for dynamic strength, pore crush, shock Hugoniot and adiabatic decompression. Experimental data have been obtained on an aggregate concrete to Hugoniot pressures of 25 GPa. New analytic methods were developed to extract equation-of-state properties from dynamic test data. Unexpected residual strain results are compared with expected thermal expansion and dilatancy properties of concrete.

Quantitative hazard assessments (QHAs) are being used to support the US Department of Energy (DOE) Integrated Safety Process (SS-21), Nuclear Explosive Safety Studies (NESS), and Environmental Safety and Health (ES&H) initiatives. The QHAs are used to identify hazards associated with DOE nuclear explosive operations. In 1994, Los Alamos National Laboratory, Sandia National Laboratory, and the Pantex Plant participated in a joint effort to demonstrate the utility of performing hazard assessments (HAs) concurrently with process design and development efforts. Early identification of high risk operations allow for process modifications before final process design is completed. This demonstration effort, which used an integrated design process (SS-21), resulted in the redesign of the dismantlement process for the B61 center case. The SS-21 program integrates environment, safety, and health (ES&H) and nuclear explosive safety requirements. QHAs are used to identify accidents that have the potential for worker injury or public health or environmental impact. The HA is to evaluate the likelihood of accident sequences that have the potential for worker or public injury or environmental damage; identify safety critical tooling and procedural steps; identify operational safety controls; identify safety-class/significant systems, structures and components; identify dominant accident sequences; demonstrate that the facility Safety Analysis Report …

During the past several years a range of spectroscopies, including fluorescence and elastic-scatter spectroscopy, have been investigated for optically based detection of cancer and other tissue pathologies. Both elastic-scatter and fluorescence signals depend, in part, on scattering and absorption properties of the cells in the tissue. Therefore an understanding of the scattering and absorption properties of cells is a necessary prerequisite for understanding and developing these techniques. Cell suspensions provide a simple model with which to begin studying the absorption and scattering properties of cells. In this study we have made preliminary measurements of the scattering and absorption properties of suspensions of mouse mammary carcinoma cells (EMT6) over a broad wavelength range (380 nm to 800 nm).

Automotive alternators are designed to supply power for automobile engine ignition systems as well as charge the storage battery. This product is used in a large market where consumers are concerned with acoustic noise and vibration that comes from the unit. as well as overall quality and dependability. Alternators and generators in general are used in industries other than automotive, such as transportation and airline industries and in military applications. Their manufacturers are interested in pursuing state-of-the-art methods to achieve higher quality and reduced costs. Preliminary investigations of non-intrusive diagnostic techniques utilizing the inherent voltage signals of alternators have been performed with promising results. These techniques are based on time and frequency domain analyses of specially conditioned signals taken from several alternators under various test conditions. This paper discusses investigations that show correlations of the alternator output voltage to airborne noise production. In addition these signals provide insight into internal magnetic characteristics that relate to design and/or assembly problems.

The disposal of mixed low-level waste has become an issue for the U.S. Department of Energy and the States since the inception of the Federal Facilities Compliance Act in 1992. Fifteen sites, including Sandia National Laboratories (SNL) and Los Alamos National Laboratory (LANL), have been evaluated to estimate their technical capabilities for disposal of this type of waste after it has been subjected to treatment processes. The analyses were designed to quantify the maximum permissible concentrations of radioactive and hazardous constituents in mixed low-level waste that could potentially be disposed of in a facility at one of the fifteen sites and meet regulatory requirements. The evaluations provided several major insights about the disposal of mixed low-level waste. All of the fifteen sites have the technical capability for disposal of some waste. Maximum permissible concentrations for the radioactive component of the waste at and sites such as SNL and LANL are almost exclusively determined by pathways other than through groundwater. In general, for the hazardous component of the waste, travel times through groundwater to a point 100 meters from the disposal facility are on the order of thousands of years. The results of the evaluations will be compared to actual treated …

In this paper we present parallel solvers for large linear systems arising from the finite-element discretization of three-dimensional groundwater flow problems. We have tested our parallel implementations on the Intel Paragon XP/S 150 supercomputer using up to 1024 parallel processors. Our solvers are based on multigrid and Krylov subspace methods. Our goal is to combine powerful algorithms and current generation high performance computers to enhance the capabilities of computer models for groundwater modeling. We demonstrate that multigrid can be a scalable algorithm on distributed memory machines. We demonstrate the effectiveness of parallel multigrid based solvers by solving problems requiring more than 64 million finite-elements in less than a minute. Our results show that multigrid as a stand alone solver works best for problems with smooth coefficients, but for rough coefficients it is best used as a preconditioner for a Krylov method.

Recent developments in molecular dynamics furnish new interconnections among three classical fields: particle mechanics, continuum mechanics, and thermodynamics. The resulting links clarify the importance of Lyapunov instability to irreversibility.

The Molten Salt Reactor Experiment (MSRE) is an 8 MW reactor that was operated at Oak Ridge National Laboratory (ORNL) from 1965 through 1969. The reactor used a unique liquid salt fuel, composed of a mixture of LIF, BeF{sub 2}, ZrF{sub 4}, and UF{sub 4}, and operated at temperatures above 600{degrees}C. The primary fuel salt circulation system consisted of the reactor vessel, a single fuel salt pump, and a single primary heat exchanger. Heat was transferred from the fuel salt to a coolant salt circuit in the primary heat exchanger. The coolant salt was similar to the fuel salt, except that it contains only LiF (66%) and BeF, (34%). The coolant salt passed from the primary heat exchanger to an air-cooled radiator and a coolant salt pump, and then returned to the primary heat exchanger. Each of the salt loops was provided with drain tanks, located such that the salt could be drained out of either circuit by gravity. A single drain tank was provided for the non-radioactive coolant salt. Two drain tanks were provided for the fuel salt. Since the fuel salt contained radioactive fuel, fission products, and activation products, and since the reactor was designed such that the …

A feasibility study of a compact high power density target for a spallation neutron source was under-taken. The target arrangement consists primarily of heavy metal, with appropriate cooling passages. A high intensity proton beam of intermediate energy is directed at the target, where it interacts with the heavy metal nuclei. The subsequent spallation reactions produce several neutrons per proton resulting in an intense neutron source. The proton beam is assumed to havean energy of 5 MW, and to be cyclic with a repetition rate of 10Hz and 50Hz. The study was divided into two broad sections. First, an analysis of preliminary target designs was undertaken to ensure the overall feasibility of the concepts involved in the design and eventual construction of such a high power density target. Second, two proposed target designs, based on the first set of analyses, are investigated in more detail. Special care is taken to ensure that the neutron fluxes in the moderator are at the desired level no material compatibility problems exist,and the target is able to operate in a reliable and safe manner. Several target materials, coolant types, and target arrangements are investigated in the first section. The second section concentrates on a single …

Detection of smuggled nuclear materials at transit points requires monitoring unknown samples in large closed packages. This review contends that high-confidence nuclear-material detection requires induced fission as the primary mechanism, with passive radiation screening in a complementary role. With the right equipment, even small quantities of nuclear materials are detectable with a high probability at transit points. The equipment could also be linked synergistically with detectors of other contrabond. For screening postal mail and packages, passive monitors are probably more cost-effective. When a suspicious item is detected, a single active probe could then be used. Until active systems become mass produced, this two-stage screening/interrogation role for active/passive equipment is more economic for cargo at border crossings. For widespread monitoring of nuclear smuggling, it will probably be necessary to develop a system for simultaneously detecting most categories of contraband, including explosives and illicit drugs. With control of nuclear materials at known storage sites being the first line of defense, detection capabilities at international borders could establish a viable second line of defense against smuggling.

This paper provides information on the volume of TRU waste loads requiring treatment, storage, and disposal at DOE facilities for three siting configurations. Input consisted of updated inventory and generation data from. Waste Isolation Pilot plant Transuranic Waste Baseline Inventory report. Results indicate that WIPP`s design capacity is sufficient for the CH TRU waste found throughout the DOE Complex.

A new approach for processing of piecewise-constant signals is proposed. It is based on modeling the observed data as a sum of a random signal and noise. The random signal has a Gibbs distribution, and the noise is Gaussian. A MAP criterion in derived for joint estimation of the number of signal levels and reconstruction of signal. The criterion comprises of three terms, one corresponding to the likelihood of the data and two to penalties. One penalty term penalizes for unnecessary transitions, and the other, for unnecessary levels. The method has been tested on synthesized data and applied to single ion channel recording.