How will we ever be convinced that grand unification, or string theory, or some other physics at very high energies, is correct? Two ways in which this could happen are: The structure of the theory is itself so compelling and tightly constrained, and the links to observed particle interactions are sufficiently strong, that the theory is convincing and is accepted as the standard viewpoint. String theory is a candidate for such a theory, but connections to known physics will require much further understanding of the breaking of its many symmetries. The theory predicts new physics beyond the standard model, which is discovered. If the structure of the theory is not very tightly constrained, several such predictions will be necessary for it to become convincing. Grand unification is a candidate for such a theory, but as yet there have been no discoveries beyond the standard model. Supersymmetric grand unified theories do have a constrained gauge structure, and this has led to the successful prediction of the weak mixing angle at the percent level of accuracy While significant, this is hardly convincing. Never-the-less, supersymmetric grand unified theories offer the prospect of many further tests. In this talk I make the case that …

The objective of the workshop was to promote discussions between experts and research managers on developing approaches for assessing the impact of DOE`s basic energy research upon the energy mission, applied research, technology transfer, the economy, and society. The purpose of this impact assessment is to demonstrate results and improve ER research programs in this era when basic research is expected to meet changing national economic and social goals. The questions addressed were: (1) By what criteria and metrics does Energy Research measure performance and evaluate its impact on the DOE mission and society while maintaining an environment that fosters basic research? (2) What combination of evaluation methods best applies to assessing the performance and impact of OBES basic research? The focus will be upon the following methods: Case studies, User surveys, Citation analysis, TRACES approach, Return on DOE investment (ROI)/Econometrics, and Expert panels. (3) What combination of methods and specific rules of thumb can be applied to capture impacts along the spectrum from basic research to products and societal impacts?

Article on signal-transduction pathways controlling light-regulated development in Arabidopsis.

The introduction of a divertor Thomson scattering system in DIII-D has enabled accurate determination of the plasma properties in the divertor region. We identify two plasma regimes; detached and attached. The electron temperature in the detached regime is about 2 eV, much lower than 5 to 10 eV determined earlier. We show that fluid models of the DIII-D scrape-off layer plasma are able to reproduce many of the features of these two plasma regimes, including the boundaries for transition between them. Detailed comparison between the results obtained from the fluid models and experiment suggest the models underestimate the spatial extent of the low temperature region associated the detached plasma mode. We suggest that atomic physics processes at the low electron temperatures reported here may account for this discrepancy.

The central peak in SrTiO{sub 3} was first observed by Riste and his collaborators in 1971. This was one of the key discoveries leading to an understanding of the dynamics of phase transitions. The most recent discovery of two length scales in SrTiO{sub 3} motivated a reinvestigation of the soft phonon and associated central peak by neutron scattering. These recent experiments shed new light on the nature of the central peak. It is now well established to be strongly sample dependent and it originates from defects in bulk crystals.

GROCSE (Gamma-Ray Optical Counterpart Search Experiments) is a system of automated telescopes that search for simultaneous optical activity associated with gamma ray bursts in response to real-time burst notifications provided by the BATSE/BACODINE network. The first generation system, GROCSE 1, is sensitive down to Mv {approximately} 8.5 and requires an average of 12 seconds to obtain the first images of the gamma ray burst error box defined by the BACODINE trigger. The collaboration is now constructing a second generation system which has a 4 second slewing time and can reach Mv {approximately} 14 with a 5 second exposure. GROCSE 2 consists of 4 cameras on a single mount. Each camera views the night sky through a commercial Canon lens (f/1.8, focal length 200 mm) and utilizes a 2K x 2K Loral CCD. Light weight and low noise custom readout electronics were designed and fabricated for these CCDs. The total field of view of the 4 cameras is 17.6 x 17.6 {degree}. GROCSE II will be operated by the end of 1995. In this paper, the authors present an overview of the GROCSE system and the results of measurements with a GROCSE 2 prototype unit.

The Yucca Mountain Site Characterization Project is investigating Yucca Mountain, Nevada, for its suitability as a potential repository for high-level nuclear wastes. United States federal regulation 10CFR60 requires that radioactive nuclides be substantially contained in waste packages for 300 to 1000 years after the emplacement. To meet the regulation, a waste package container should remain intact for several hundreds of years. It has been shown that high humidity increases the corrosion potential of metallic container materials. Relative humidity as a function of water saturation in intact rock is measured. The results of this test can be used to calibrate the relative humidity in the near-field environment predicted by model calculations using thermal-hydrological codes such as VTOUGH. This is a report on the progress of that experiment.

The GROCSE I experiment (Gamma-Ray Optical Counterpart Search Experiment) is a rapid slewing wide field of view optical telescope at Lawrence Livermore National Laboratory which responds to triggers from the BATSE GRB data telemetry stream that have been processed and distributed by the BACODINE network. GROCSE 1 has been in continuous automated operation since January 1994. As of October 1995, sky images for 22 GRB triggers have been recorded, in some cases while the burst was still emitting gamma rays. The preliminary analysis of eight of these events are presented here. No optical counterparts have yet been detected. Limits for optical emission are given.

Knowledge of how water flows through unsaturated, fractured rock is critical for understanding and predicting the performance of a high- level nuclear waste repository. For instance, during gravity driven fracture flow, the distance that water can travel through a fracture network might be controlled by (1) the amount of water available, (2) the fracture aperture, (3) the capillary properties of the matrix, and (4) the saturation of the matrix. We have experimentally investigated fracture flow and fracture-matrix interactions using x- ray radiography to image some of the above factors and processes.

The damage to high-level radioactive-waste containers by pitting corrosion is an important design and performance assessment consideration. It is desirable to calculate the evolution of the pit depth distribution, not just the time required for initial penetration of the containers, so that the area available for advective of diffusive release of radionuclides through the container can be estimated. A phenomenological approach for computing the time evolution of these distributions is presented which combines elements of the deterministic and stochastic aspects of pit growth. The consistency of this approach with the mechanisms believed to control the evolution of the pit depth distribution is discussed. Qualitative comparisons of preliminary model predictions with a variety of experimental data from the literature are shown to be generally favorable. The sensitivity of the simulated distributions to changes in the input parameters is discussed. Finally, the results of the current model are compared to those of existing approaches based on extreme-value statistics, particularly regarding the extrapolation of laboratory data to large exposed surface areas.

We report here on the results of experiments concerning particular bonding processes potentially useful for ultimate miniaturization of microfluidic systems. Direct anodic bonding of continuous thin pyrex glass of 250 {mu}m thickness to silicon substrates gives multiple, large voids in the glass. Etchback of thick glass of 1200 {mu}m thickness bonded to silicon substrates gives thin continuous glass layers of 189 {mu}m thickness without voids over areas of 5 cm {times} 12 cm. Glass was also successfully bonded to glass by thermal bonding at 800{degrees}C over a 5 cm {times} 7 cm area. Anticipated applications include microfabricated DNA sequencing, flow injection analysis, and liquid and gas chromatography microinstruments.

A calculation of the total cross section for top quark production in hadron-hadron collisions is presented based on an all-orders perturbative resummation of initial-state gluon radiative contributions to the basic quantum chromodynamics subprocesses. For p{anti p} collisions at center-of-mass energy {radical}s = 1.8 TeV and a top mass of 175 GeV, the authors obtain {sigma}(t{anti t}) = 5.52 {sub {minus}0.45}{sup +0.07} pb. Cross sections are provided as a function of top mass at CERN LHC energies.

A new drift detector prototype which provides suppression of the lateral diffusion of electrons has been tested as a function of the signal charge up to high charge levels, when electrostatic repulsion is not negligible. The lateral diffusion of the electron cloud has been measured for injected charges up to 2 {center_dot} 10{sup 5} electrons. The maximum number of electrons for which the suppression of the lateral spread is effective is obtained.

A compact filter/mask/window assembly has been designed for undulator beamline commissioning activity at the Advanced Photon Source beamlines. The assembly consists of one 300-{mu}m graphite filter, one 127-{mu}m CVD diamond filter and two 250-{mu}m beryllium windows. A water-cooled Glidcop fixed mask with a 4.5-mm {times} 4.5-mm output optical aperture and a 0.96-mrad {times} 1.6-mrad beam missteering acceptance is a major part in the assembly. The CVD diamond filter which is mounted on the downstream side of the fixed mask is designed to also function as a transmitting x-ray beam position monitor. The sum signal from the latter can be used to monitor the physical condition of the graphite filter and prevent any possible chain reaction damage to the beryllium windows downstream. In this paper, the design concept as well as the detailed structural design of the commissioning window are presented. Further applications of the commissioning window commissioning window components are also discussed.

Closed orbit feedback for the Advanced Photon Source (APS) storage ring employs unified global an local feedback systems for stabilization of particle and photon beams based on digital signal processing (DSP). Hardware and software aspects of the system will be described. In particular, we will discuss global and local orbit feedback algorithms, PID (proportional, integral, and derivative) control algorithm. application of digital signal processing to compensate for vacuum chamber eddy current effects, resolution of the interaction between global and local systems through decoupling, self-correction of the local bump closure error, user interface through the APS control system, and system performance in the frequency and time domains. The system hardware, including the DSPS, is distributed in 20 VNE crates around the ring, and the entire feedback system runs synchronously at 4-kHz sampling frequency in order to achieve a correction bandwidth exceeding 100 Hz. The required data sharing between the global and local feedback systems is facilitated via the use of fiber-optically-networked reflective memories.

We describe the role for the next-generation ``superlasers`` in the study of matter under extremely high energy density conditions, in comparison to previous uses of nuclear explosives for this purpose. As examples, we focus on three important areas of physics that have unresolved issues which must be addressed by experiment: Equations of state, hydrodynamic mixing, and the transport of radiation. We will describe the advantages the large lasers will have in a comprehensive experimental program.

The commissioning of the 7-GeV Advanced Photon Source (APS) storage ring began in early 1995. Characterization of the stored particle beam properties involved time-resolved transverse and longitudinal profile measurements using optical synchrotron radiation (OSR) monitors. Early results include the observation of the beam on a single turn, measurements of the transverse beam sizes after damping using a 100 {mu}s integration time ({sigma}{sub x} {approximately} 150 {plus_minus} 25 {mu}m, {sigma}{sub {gamma}} {approximately} 65 {plus_minus} 25 {mu}m, depending on vertical coupling), and measurement of the bunch length ({sigma}{sub {tau}} {approximately} 25 to 55 ps, depending on the charge per bunch). The results are consistent with specifications and predictions based on the 8.2 nm-rad natural emittance, the calculated lattice parameters, and vertical coupling less than 10%. The novel, single-element focusing mirror for the photon transport line and the dual-sweep streak camera techniques which allow turn-by-turn measurements will also be presented. The latter measurements are believed to be the first of their kind on a storage ring in the USA.

Performance measurement and analysis of the Advanced Photon Source (APS) beam position monitor (BPM) electronics are reported. The results indicate a BPM resolution of 0.16 {mu}m{center_dot}mA/{radical}Hz in terms of the single-bunch current and BPM bandwidth. For the miniature insertion device (ID) BPM, the result was 0.1 {mu}m{center_dot}mA/{radical}Hz. The improvement is due to the 3.6 times higher position sensitivity (in the vertical plane), which is partially canceled by the lower button signal by a factor of 2.3. The minimum single-bunch current required was roughly 0.03 mA. The long-term drift of the BPM electronics independent of the actual beam motion was measured at 2 {mu}m/hr, which settled after approximately 1.5 hours. This drift can be attributed mainly to the temperature effect. Implications of the BPM resolution limit on the global and local orbit feedback systems for the APS storage ring will also be discussed.

We have developed a novel dispersion-reduction technique using subcarrier multiplexing (SCM) which permits the transmission of multiple 2.5 Gbit/s data channels over hundreds of kilometers of conventional fiber-optic cable with negligible dispersion. Using a lithium niobate external modulator having a modulation bandwidth of 20 GHz, we are able to multiplex several high-speed data channels at a single wavelength. At the receiving end, we demultiplex the data and detect each channel using a 2-GHz bandwidth optical detector. All of the hardware in our system consists of off-the-shelf components and can be integrated to reduce the overall cost. We demonstrated our dispersion-reduction technique in a recent field trial by transmitting two 2.5 Gbit/s data channels over 90 km of commercially-installed single-mode fiber, followed by 210 km of spooled fiber. For comparison, we substituted the 300 km of fiber with equivalent optical attenuation. We also ran computer simulations to evaluate link behavior. Technical details and field trial results will be presented.

A new methodology for the modeling of unsteady, nonpremixed, axisymmetric reacting flow in industrial furnaces is presented. The method is an extension of previous work by the authors to complex geometries, multistep kinetics mechanisms, and realistic properties, especially thermochemical data. The walls of the furnace are represented as an embedded boundary in a uniform, rectangular grid. The grid then consists of uniform rectangular cells except at the furnace wall where irregular (mixed) cells may be present. We use finite volume differencing techniques for the convective, viscous, and radiative heat transport terms in the mixed cells, while a finite element-based technique is used to solve the elliptic equation arising from the low-Mach number formulation. Results from the simulation of an experimental natural gas-fired furnace are shown.

Because of the reduction in the nation`s stockpile of weapon systems a large amount of tritium is being returned to the Savannah River Site in Aiken, SC. Due to the increased quantity of tritium returning to SRS, the SRS Tritium Facility was tasked to determine the most cost effective means to safely store the tritium gas in a short period of time. This paper presents results of the risk assessment developed to evaluate the safe storage of tritium at SRS, and highlights the structural design of the HIVES used as the cost-effective short term NPH mitigation solution.

A consistent theme in spacecraft telemetry system design is the desire to obtain maximum bandwidth utilization given a fixed transmission capability (usually due to cost/weight criteria). Extensions to basic packetization telemetry architectures are discussed which can facilitate a reduction in the amount of actual data telemetered, without loss of data quality. Central to the extensions are the establishment of an ``intelligent`` telemetry process, which can evaluate pending data to be telemetered, and act to compress, discard, or re-formulate data before actual transmission to ground stations.

Article discussing sodium and potassium currents of type I spiral ganglion cells from rat.

The NORAPS model has been used to simulate the motion of Hurricane Erin over Florida. A triplynested grid was used to capture the meteorological features which span from regional to local scales with the highest resolution nest centered at the Kennedy Space Center area. The simulated storm track agreed remarkably well with the observed path of the hurricane. There was also good qualitative agreement between the computed surface precipitation pattern and observations based on radar signatures. Although the validity of the Kuo- type cumulus parameterization scheme used in the model was marginal and even questionable on the finest resolution (4 km) nest, the simulated results were nevertheless qualitatively reasonable. The results generated by NORAPS from the simulation of such a numerical challenging meteorological event were very encouraging. Our next step is to use the meteorological information from the model to provide wind fields for dispersion model simulations of potential atmospheric releases.