Leaves show a variety of strategies for maximizing CO{sub 2} and light capture. These are more meaningfully explained if they are considered in the context of maximizing capture relative to the utilization of water, nutrients and carbohydrates reserves. There is considerable variation between crops in their efficiency of CO{sub 2} and light capture at the leaf level. Understanding of these mechanisms indicate some ways in which efficiency of resource capture could be level cannot be meaningfully considered without simultaneous understanding of implications at the canopy level. 36 refs., 5 figs., 1 tab.

The linac injector for the Advanced Light Source (ALS) at LBL was recently put into operation. Energy is 50 MeV, frequency 3 GHz. The electron gun delivers up to 6nC in a 3.0-ns bunch at 120 kV. A train of bunches is injected into a 1-Hz booster and accelerated to 1.5 GHz for storage ring injection. A magnetic analysis system is used for optimizing the linac. Measured beam properties from the gun and after acceleration in the linac are described. 9 refs., 3 figs.

A method is described for obtaining monodomain PbTiO{sub 3} single crystals with high electrical resistivity (10{sup 10}{Omega} cm) and low dielectric frequency dispersion. The single crystals of PbTiO{sub 3} were grown by flux solution method. Space charge related defects, which result in the large dielectric frequency dispersion, were eliminated by heat treatments. 90{degrees} domains were removed by applying a unidirectional compressive stress along the <100> crystallographic direction. The monodomain single crystals of PbTiO{sub 3} were identified by cross polarized light optical microscopy and by X-ray diffraction (rocking curve). The anisotropic dielectric constants of these high quality single crystals were measured as a function of temperature. The results differ from the data reported previously in the literature.

An understanding of the chemical composition of such slags under boiler operating conditions and as function of the mineral composition of various coals is the ultimate goal of this program. The experiment involves scanning through the K- or L-shell absorption edge of the element in question. The structure of the absorption edge, consisting of transitions to unoccupied molecular levels, can be compared to those of model compounds for identification. The relative position of the absorption edge can yield information regarding the oxidation state of the element. This portion is the X-ray Absorption Near Edge Structure (XANES) portion of the spectrum. The Extended X-ray Absorption Fine Structure (EXFAS) region, extending from about 60 eV above the absorption edge, represents scattering from neighboring constituents and can be used to determine the coordination number of coordination distance of a specific element from its neighboring atoms. The best source of excitation energy for these experiments is an electron storage ring emitting synchrotron radiation (SR). The National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory is a 2.5 GeV storage ring and emits a continuous spectrum of x rays to an energy of about 30 keV. Beam line X-19A is dedicated to XANES and EXAFS …

The Fermilab Tevatron Muon Experiment has analyzed the hadron showers of events resulting from the scattering of a muon beam (< E{sub {mu}} > = 490 GeV) off H{sub 2}, D{sub 2} and Xenon targets. The topics which will be discussed are: (1) space-time evolution of the hadronization process; (2) leading hadron distributions in the shadowing region; (3) rates and characteristics of 3-jet events. 23 refs.

This paper discusses issues and approaches dealing with conceptualizing, implementing, and maintaining configuration control commensurate with the conduct of operations approach defined by DOE ORDER 5480.19. Specific topics reviewed will include key elements of assessments to determine the status quo such as assessment criteria, assessment personnel, and assessment scope; administrative programs to maintain the status quo such as organizational definition, responsibilities, interfaces, and priorities; oversight to determine control effectiveness via compliance and performance assessment.

The populations of ground electronic state atomic hydrogen and ground electronic state, vibrationally-rotationally excited hydrogen molecules in a negative hydrogen ion source discharge have been measured using vacuum ultraviolet (VUV) laser absorption spectroscopy. Vibrational states up to v=8 and rotational levels as high as J=15 have been measured. The measurements have been made under a range of discharge conditions. The complete vibrational population distribution for v=1-8, J=1 has been obtained. The vibrational distribution appears to be thermalized and does not exhibit a plateau'' at the higher vibrational levels, in contrast to most models of this system. In contrast, the high rotational states are populated suprathermally. These determinations indicate that rotationally excited molecules may play an important role in the production of H{sup minus} in these sources. 5 refs., 5 figs.

Interest in the mechanisms of interaction and the biological effects of static magnetic fields has increased significantly during the past two decades as a result of the growing number of applications of these fields in research, industry and medicine. A major stimulus for research on the bioeffects of static magnetic fields has been the effort to develop new technologies for energy production and storage that utilize intense magnetic fields (e.g., thermonuclear fusion reactors and superconducting magnet energy storage devices). Interest in the possible biological interactions and health effects of static magnetic fields has also been increased as a result of recent developments in magnetic levitation as a mode of public transportation. In addition, the rapid emergence of magnetic resonance imaging as a new clinical diagnostic procedure has, in recent years, provided a strong rationale for defining the possible biological effects of magnetic fields with high flux densities. In this review, the principal interaction mechanisms of static magnetic fields will be described, and a summary will be given of the present state of knowledge of the biological, environmental, and human health effects of these fields.

The effect of Au on the reliability of 0.65 mm pitch surface mount solder joints between plastic quad flat packs and Cu-Ni-Au FR-4 printed circuit boards was investigated. Cu-Ni-Au is a desirable printed circuit board finish for multi-chip modules or printed circuit boards that would otherwise require a selective Au finish, for example for edge connectors or wire bondable parts. However, Au is known to embrittle solder when it is present in sufficiently high concentrations, creating a concern that solder joint fatigue life in service will also be adversely affected. This paper reports the results of mechanical shock, mechanical vibration and thermal cycling testing of fine pitch solder joints containing varying amounts of Au. Tests were performed on as-soldered joints and on joints that had been heat-treated to evolve the microstructure toward equilibrium. The tests were designed to accelerate in-service conditions in a typical industrial environment. Under these conditions, the Au concentrations tested did not promote solder joint failures. Microstructural characterization of the distribution and morphology of the Au-, Ni-, and Cu-Sn intermetallics in the joint before and after accelerated testing was also performed. On the basis of these observations it is recommended that the Au concentration in solder joints …

Triplets composed of superconducting quadrupoles have been built and installed as the final focusing element for the high-energy positron and electron beams of the SLAC Linear Collider. Special features include independent alignment to 100-micron tolerance inside a common cryostat; non-magnetic materials to allow operation inside the detector's solenoid field; a continuous-flow helium-only system using 50-meter-long flexible transfer lines; and complete operation of the system before installation. The mechanical design and cryogenic operation experience are presented.

In Karkow, Poland almost half of the energy used for heating is supplied by local, solid-fuel-fired boilerhouses and home stoves. These facilities are referred to as the low emission sources'' and are primary contributors of particulates and hydrocarbon air pollution in the city and secondary contributors of sulfur dioxide and carbon monoxide. The Support of Eastern European Democracy Act of 1989 directed the US Department of Energy to undertake an equipment assessment project aimed at developing the capability within Poland to manufacture or modify industrial-scale combustion equipment to utilize fossil fuels cleanly. The Project is being conducted in a manner that can be generalized to all of Poland and uito the rest of Eastern Europe. The project plan includes three phases which have been developed around five specific subprojects. In Phase 1, technical and economic assessments will be made of pollution reduction options for the five subprojects. Phase 2 plans call for public meetings in the US and Poland for companies interested in forming joint ventures. Information will be available in these meetings to enable companies to identify markets and select potential partners that meet with their capabilities and interests. In Phase 3, DOE will issue a solicitation for Polish/American …

VISAR (Velocity Interferometer System for Any Reflector) is commonly used for measuring flyer-plate velocities up to 6 km/s. Flyer plates can travel as much as 1 mm, which is large compared to usual depth-of-focus requirements for VISARs. Flyer plates are explosively driven, or driven by some other very energetic means; as such, they must be tested in a chamber, which will contain the explosion. Routing the laser beam to the chamber and the signal beam to the VISAR can be done safely and easily in multi-mode optical fibers. We have optimized a fiber-coupled VISAR system for measuring flyer-plate velocities. This system given constant signal levels over the full travel of the flyer plate. Furthermore, the signal-collection efficiency is maximized, which allows use of a moderately sized laser. We also have optimized the VISAR cavity so it does not limit the system efficiency while giving a velocity sensitivity of about 1 km/s per fringe. 5 refs.

The effectiveness of water sprays in absorbing HF releases was recently demonstrated in extended laboratory and field tests. In this paper, computer simulations are presented of the Hawk, Nevada Test Site, series of field tests. The model used, HFSPRAY, is a Eulerean/Lagrangian model which simulates the momentum, mass and energy interactions between a water spray and a turbulent plume of HF in air; the model can predict the flow velocities, temperature, water vapor, and HF concentration fields in two-dimensional large- geometries for spraying in any direction, (i.e., down-flow, inclined-down-flow, up-flow, and co-current horizontal flow). The model was validated against recent data on spraying of water on large releases of HF. 17 refs., 11 figs., 4 tabs.

A jet-cell based vertex chamber has been built for the D{O} experiment at Fermilab and operated in a test beam there. Low drift velocity and diffusion properties were achieved using CO{sub 2}(95%)-ethane(5%) at atmospheric pressure. The drift velocity is found to be consistent with (9.74+8.68( E -1.25)) {mu}m/nsec where E is the electric field strength in (kV/cm < E z 1.6 kV/cm.) An intrinsic spatial resolution of 60 {mu}m or better for drift distances greater than 2 mm is measured. The track pair efficiency is estimated to be better than 90% for separations greater than 630 {mu}m. 8 refs., 6 figs., 1 tab.

My first encounter with a quality assurance auditor is reminiscent of an old Dodge commercial. You remember The old sheriff, masked in mirrored sunglasses, paunch hanging over his gun belt, prophesying, You're in a heap o' trouble boy '' Well, my auditor could have been kin to the sheriff; they had the same posture, attitude, and mirrored sunglasses. Plus, my auditor wore a black leather vest and sported a Buffalo Bill'' goatee. While certainly memorable, both gentlemen were far from pleasant. I'm fairly certain that the compliance auditor of old deserved this perceived association with his law enforcement counterpart. Both believed in enforcing the letter of the law, or their interpretations of it. Neither seemed capable of exercising interpretive powers, but instead relied on winning through intimidation, possibly with an eye toward claiming some version of a monthly Quota Award. Is the auditor of today any better perceived Because this first encounter of the worst kind'' made a lasting impression on me, I have dedicated considerable time and effort trying to avoid being perceived as another sheriff when I conduct audits. In my auditing career, I am determined to capitalize on each opportunity to turn negative situations, as experienced by …

The Advanced Light Source (ALS), now under construction at Lawrence Berkeley Laboratory, is a third-generation synchrotron radiation source designed to produce extremely bright photon beams in the UV and soft X-ray regions. The lattice magnets to be installed in the two rings, a 1--1.9 GeV storage ring, and a 1.5 GeV booster synchrotron, have been magnetically measured to ascertain their excitation curves and field uniformity. In this paper the analysis of these data is discussed, and results for measured magnets are given. 5 refs., 2 figs., 7 tabs.

It is hardly necessary to emphasize the importance that an accurate prediction of the parameters of critical flow plays in a number of industries, notably in nuclear reactor safety calculations and in metering. In spite of its importance, the literature of the subject still contains erroneous statements. Many of them result from an unjustified belief in the generality of certain conclusions drawn in the elementary study of one-dimensional isentropic flow of a perfect gas with constant specific heats through a convergent-divergent (de Laval) nozzle. This lecture will present a complete and consistent theory of such flows, applicable to any fluid (single- or multiphase) and any channel shape. The study is restricted to the one-dimensional approximation, and, although only adiabatic conditions are discussed, the formalism can be extended to arbitrary conditions at the boundary of the channel. A scrutiny of some of the latest critical reviews of the state of the art of modelling thermal-hydraulic phenomena, especially in the context of LWR safety analysis, reveals the persistence of some misconceptions concerning the nature of the flow and of the relation between the preferred mathematical model and its discretized equivalent. It has recently become clear that the ensemble of trajectories in phase …

Development of automated test equipment for an advanced telemetry system requires continuous monitoring of PCM data while exercising telemetry inputs. This requirements leads to a large amount of data that needs to be stored and later analyzed. For example, a data stream of 4 Mbits/s and a test time of thirty minutes would yield 900 Mbytes of raw data. With this raw data, information needs to be stored to correlate the raw data to the test stimulus. This leads to a total of 1.8 Gb of data to be stored and analyzed. There is no method to analyze this amount of data in a reasonable time. A data compression method is needed to reduce the amount of data collected to a reasonable amount. The solution to the problem was data reduction. Data reduction was accomplished by real time limit checking, time stamping, and smart software. Limit checking was accomplished by an eight state finite state machine and four compression algorithms. Time stamping was needed to correlate stimulus to the appropriate output for data reconstruction. The software was written in the C programming language with a DOS extender used to allow it to run in extended mode. A 94--98% compression in …

This document discusses thermal performance envelopes which are used to specify steady-state design requirements for the systems of the Modular High Temperature Gas-Cooled Reactor to maximize plant performance reliability with optimized design. The thermal performance envelopes are constructed around the expected operating point accounting for uncertainties in actual plant as-built parameters and plant operation. The components are then designed to perform successfully at all points within the envelope. As a result, plant reliability is maximized by accounting for component thermal performance variation in the design. The design is optimized by providing a means to determine required margins in a disciplined and visible fashion.

We are literally surrounded by radiofrequency (RFR) and microwave radiation, from both natural and man-made sources. The identification and control of man-made sources of RFR has become a high priority of radiation safety professionals in recent years. For the purposes of this paper, we will consider RFR to cover the frequencies from 3 kHz to 300 MHz, and microwaves from 300 MHz to 300 GHz, and will use the term RFR interchangeably to describe both. Electromagnetic radiation and field below 3 kHz is considered Extremely Low Frequency (ELF) and will not be discussed in this paper. Unlike x- and gamma radiation, RFR is non-ionizing. The energy of any RFR photon is insufficient to produce ionizations in matter. The measurement and control of RFR hazards is therefore fundamentally different from ionizing radiation. The purpose of this paper is to acquaint the reader with the fundamental issues involved in measuring and safely using RFR fields. 23 refs.

Significant progress has been made toward solving the century-old problem of chromatic aberrations in diffractive optics. Our approach exploits modern materials and microfabrication technology and is very different from the purely diffractive strategy,'' which is commonly employed and which results in multiple diffractive elements separated by a finite distance. We have developed a Fresnel zone plate lens comprised of a serial stack of patterned minus-filters which allows broadband radiation to be focused (or imaged) without longitudinal or transverse chromatic aberrations. 7 refs., 4 figs.

This paper summarizes a system integration approach to residential heating, cooling, and ventilation, embodied in a tight building envelope with precooling and dehumidification of forced ventilation air, and with ducts in the conditioned space.

A customary approach to auditing and reporting deficiencies is to keep a running list of those that are found, evaluate the severity of each, and based on the evidence, document findings or observations or concerns in an audit report. The report is issued and the auditee is normally requested to address root cause'' as part of their corrective action. This paper describes a root problems'' approach to documenting audit findings that is designed not only to put the QA auditor in a more favorable light, but to more effectively enable the auditee to identify root cause and meaningful corrective action. The positive results of this approach are considerable. You will have fewer findings but those you do have will be substantial. You will cite requirements that sound reasonable and make arguments difficult. If some of the supporting deficiencies (examples) prove to be incorrect, you will still have ample support for the original finding. You will be seen as reasonable individual who can help lead the auditee towards identification of root cause without taking away part of the responsibility. You even have a fair chance of fostering a sense of commitment to quality improvement on the auditee's part. This in itself, …

Characterization of ceramic matrix composites (continuous and whisker-type) by nondestructive evaluation (NDE) methods and an understanding of fracture behavior, together with correlation of fracture and NDE data, may provide insight into the prediction of component performance and the development of process technology. Knowledge of the degradation extent of fiber tows or monofilament degradation after processing, extent of open porosity before densification, and filament/fiber alignments before and after processing are also examples of important variables to be measured. Work in this program has emphasized continuous fiber ceramic matrix composites (CFCCs) that use chemical vapor infiltration (CVI)-infiltrated SiC/SiC materials, primarily those made of Nicalon satin or plain weave with 16 {times} 16 tows/in. in 2-D layups. All studied samples were provided by Oak Ridge National Laboratory and were made using 100 layers per inch. CVI specimens with 0/30/60, 0/90, and 0/45 were examined by 3-D X-ray microtomography to characterize in-plane fiber orientations. Current information suggests that for Nicalon-type fiber architecture, a {plus minus}2--1/2{degrees} misalignment may not affect mechanical properties. Thus the near-term goal has been to establish a detection capability for angular orientation. By using 512 {times} 512 images from 3-D X-ray CT data with pixel sizes of < 140 {mu}m and …