Article describes how in recent years, high entropy alloys (HEAs) have been shown to be promising alternatives to common engineering alloys, depending on their composition and thermomechanical processing. In the present work, Gas Tungsten Arc Welding (GTAW) was used to achieve defect-free joints based on a novel transformation induced plasticity (TRIP) Fe50Mn30Co10Cr10 HEA.

Article describes how decreasing HVAC energy consumption through insulation effectiveness enables low energy use, low carbon emissions, and high thermal comfort in sustainable buildings. In this paper, two PCMs with transition temperature above and below the outdoor temperature incorporated in highly porous flexible polyurethane foam were evaluated using a one-dimensional (1D) foam core panel built in COMSOL Multiphysics®.

This article reports the holographic fabrication of three types of 3D graded photonic super-crystals (GPSCs) through nine beam interferences and their characteristic diffraction patterns.

Article integrating ecophysiological information with the development of new high-resolution climatic layers for Antarctica, to better understand how the distribution of P. steinenii may respond to change over the next century under different IPCC climate change scenarios. The authors conclude that the species has the potential to expand its distribution to include parts of the west and east coasts of the Antarctic Peninsula and even coastal ice-free areas in parts of continental Antarctica. The authors also propose P. steinenii as an effective native sentinel and indicator species of climate change in the Antarctic.

Accepted Manuscript version of an article presenting the design and development of a smart garment called MyWear that continuously monitors and collects physiological data. It can analyze muscle activity, stress levels, and heart rate variations and send all the data to the cloud. With a in-built alert system, it can notify the associated medical officials if necessary. The authors also propose a deep neural network model that classifies heartbeat data into abnormalities with 96.9% accuracy and 97.3% precision.

Article describes a collaborate study between University of North Texas and Toyota Connected focusing on how to structure and manage multiteam systems (MTSs).

Study describes the use of a non-cytotoxic dose of histone deacetylase (HDAC) inhibitors to induce pulmonary carcinoid somatostatin receptor subtype 2 (SSTR2) expression to diagnose pulmonary carcinoids.

We present results from searches for top quark production in p[bar p] collisions at the Tevatron collider based on an integrated luminosity of 7.5 pb[sup [minus]1] obtained during the 1992--1993 ran. The present results are confined to decay modes where both the top and anti-top quarks in the event decay semi-leptonically to the ee and e[mu] channels. A lower limit of 103 (99) GeV/c[sup 2] is obtained at 95% confidence level for the top quark mass from the absence of events consistent with standard model top quark decays with background subtraction (no background subtraction). We do however observe one event in the e[mu] channel which cannot be explained by the known backgrounds. While we make no claim that this event is due to top quark decay, it is not inconsistent with a top quark mass in the range 130--170 GeV/c[sup 2]

Accurate multi-dimensional modeling of detonation waves in solid HE materials is a difficult task. To treat applied problems which contain detonation waves one must consider reacting flow with a wide range of length-scales, non-linear equations of state (EOS), and material interfaces at which the detonation wave interacts with other materials. To be useful numerical models of detonation waves must be accurate, stable, and insensitive to details of the modeling such as the mesh spacing, and mesh aspect ratio for multi-dimensional simulations. Studies we have performed show that numerical simulations of detonation waves can be very sensitive to the form of the artificial viscosity term used. The artificial viscosity term is included in our ALE hydrocode to treat shock discontinuities. We show that a monotonic, second order artificial viscosity model derived from an approximate Riemann solver scheme can strongly damp unphysical oscillations in the detonation wave reaction zone, improving the detonation wave boundary wall interaction. These issues are demonstrated in 2D model simulations presented of the 'Bigplate' test. Results using LX-I 7 explosives are compared with numerical simulation results to demonstrate the affects of the artificial viscosity model.

We are investigating a novel insulator concept that involves the use of alternating layers of conductors and insulators with periods less than 1 mm. These structures perform 1.5 to 4 times better than conventional insulators in long pulse, short pulse, and alternating polarity applications. We survey our ongoing studies investigating the performance under long pulse electron beam, short pulse, and full reversing conditions.

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory is a stadium-sized facility that, when completed in 2008, will contain a 192-beam, 1.8- Megajoule, 500-Terawatt, ultraviolet laser system together with a 10-meter-diameter target chamber and room for 100 diagnostics. NIF is the world's largest and most energetic laser experimental system and will provide a scientific center to study inertial confinement fusion and matter at extreme energy densities and pressures. NIF's energetic laser beams will compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. Other NIF experiments will study physical processes at temperatures approaching 10{sup 8} K and 10{sup 11} bar; conditions that exist naturally only in the interior of stars and planets. NIF has completed the first phases of its laser commissioning program. The first four beams of NIF have generated 106 kilojoules in 23-ns pulses of infrared light and over 16 kJ in 3.5- ns pulses at the third harmonic (351 nm). NIF's target experimental systems are being commissioned and experiments have begun. This paper provides a detailed look the NIF laser systems, laser and optical performance, and results from recent laser commissioning shots. We follow this with …

In order to address the interactive and evolutionary nature of the cloud-radiation interaction, we have coupled to a Large Eddy Simulation (LES) model the sophisticated multi-dimensional radiative transfer (MDRT) scheme of Evans (Spherical Harmonics Discrete Ordinate Method; 1998). Because of computational expense, we are at this time only able to run 2D experiments. Preliminary runs consider only the broadband longwave component, in large part because IR cloud top cooling is the significant forcing mechanism for marine stratocumulus. Little difference is noted in the evolution of unbroken stratocumulus between three-hour runs using MDRT and independent pixel approximation (IPA) for 2D domains of 50 km in the horizontal and 1.5 km in the vertical. Local heating rates differ slightly near undulating regions of cloud top, and a slight bias in mean heating rate from 1 to 3 h is present, yet the differences are never strong enough to result in a pronounced evolutionary bias in typical boundary layer metrics (e.g. inversion height, vertical velocity variance, TKE). Longer integration times may eventually produce a physical response to the bias in radiative cooling rates. A low-CCN case, designed to produce significant drizzle and induce cloud breakup does show subtle differences between MDRT and IPA. …

With the first four of its eventual 192 beams now executing shots and generating more than 100 kilojoules of laser energy at its primary wavelength of 1.06 {micro}m, the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is already the world's largest and most energetic laser. The optical system performance requirements that are in place for NIF are derived from the goals of the missions it is designed to serve. These missions include inertial confinement fusion (ICF) research and the study of matter at extreme energy densities and pressures. These mission requirements have led to a design strategy for achieving high quality focusable energy and power from the laser and to specifications on optics that are important for an ICF laser. The design of NIF utilizes a multipass architecture with a single large amplifier type that provides high gain, high extraction efficiency and high packing density. We have taken a systems engineering approach to the practical implementation of this design that specifies the wavefront parameters of individual optics in order to achieve the desired cumulative performance of the laser beamline. This presentation provides a detailed look at the causes and effects of performance degradation in large laser systems …

Lawrence Livermore National Laboratory has designed and constructed a test stand to improve the voltage regulation in our Flash X-Ray (FXR) accelerator cell. The goal is to create a more mono-energetic electron beam that will create an x-ray source with a smaller spot size. Studying the interaction of the beam and pulse-power system with the accelerator cell will improve the design of high-current accelerators at Livermore and elsewhere. On the test stand, a standard FXR cell is driven by a flexible pulse-power system and the beam current is simulated with a switched center conductor. The test stand is fully instrumented with high-speed digitizers to document the effect of impedance mismatches when the cell is operated under various full-voltage conditions. A time-domain reflectometry technique was also developed to characterize the beam and cell interactions by measuring the impedance of the accelerator and pulse-power component. Computer models are being developed in parallel with the testing program to validate the measurements and evaluate different design changes. Both 3D transient electromagnetic and circuit models are being used.

Experiments to study beam dynamics for Relativistic Klystrons (RK) are being performed with a 1-MeV, 600-A induction accelerator beam. The RK is a RF Power source based on induction accelerator technology and conventional resonant output structures. Capable of generating 100's of MW/m at frequencies up to K-band, the RK has been proposed as a driver for a future linear collider in one version of a Two-Beam Accelerator. A critical feasibility issue remaining to be demonstrated is suppression of the transverse instability of the drive beam. This kiloampere beam must transit about a hundred resonance output structures and many hundreds of induction accelerator cavities for the RK to achieve competitive efficiency and cost with respect to other proposed power sources. The RK's strong focusing used to contain the beam in the small aperture resonant structures, repetitive geometry, and reacceleration allow the resonant output structures to be spaced at a betatron phase advance of 360{sup o}. This phase advance (or any integral multiple of 180{sup o}) is beneficial in linear accelerators as the instability growth changes from exponential to linear. In our experiment the beam is contained in a solenoidal focusing channel, RF cavities are spaced every 60 cm, and growth in …

Density-functional electronic-structure calculations for PuCoGa{sub 5} are performed to address the possibility of magnetic interactions in this high-temperature superconductor. Within an itinerant 5f-electron picture, cohesion and crystallographic parameters compares favorably with experiment, whereas only when spin and orbital interactions are accounted for the calculated electronic density of states agrees with photoemission spectra. This fact suggests that spin and orbital correlations are important for a correct description of the PuCoGa{sub 5} electronic structure and may play a role in an unconventional mechanism for superconductivity.

Triggered, multi-channel, surface discharges or surface flashover switching have been investigated as a low inductance, low pulse rate switch for conducting large currents. This paper discusses the investigation of UV (355 nm) laser triggered, single channel, low inductance, ns closure and sub-ns jitter switches for applications in switching high dielectric constant, compact pulse forming lines into accelerator loads. The experimental arrangement for evaluating the switch performance and for measuring the high field dielectric constant of the pulse forming lines is presented. Experimental results of delay and jitter measurements versus optical energy on the flashover surface and dc electric field charge.

Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH2) or ambient-temperature compressed hydrogen (CH2). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Required future tests are described that will prove that no technical barriers exist to the safe use of aluminum-fiber vessels at cryogenic temperatures. Future activities also include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for obtaining certification for insulated pressure vessels.

Use of a large-area liquid lithium surface as a first wall has significantly improved the plasma performance in the Current Drive Experiment-Upgrade (CDX-U) at the Princeton Plasma Physics Laboratory. Previous CDX-U experiments with a partially-covered toroidal lithium limiter tray have shown a decrease in impurities and the recycling of hydrogenic species. Improvements in loading techniques have permitted nearly full coverage of the tray surface with liquid lithium. Under these conditions, there was a large drop in the loop voltage needed to sustain the plasma current. The data are consistent with simulations that indicate more stable plasmas having broader current profiles, higher temperatures, and lowered impurities with liquid lithium walls. As further evidence for reduced recycling with a liquid lithium limiter, the gas puffing had to be increased by up to a factor of eight for the same plasma density achieved with an empty toroidal tray limiter.

The maximum vacuum insulator surface dielectric strength determines the acceleration electric field gradient possible in a short pulse accelerator. Previous work has indicated that higher electric field strengths along the insulator-vacuum interface might be obtained as the pulse duration is decreased. In this work, a 250 kV, single ns wide impulse source was applied to small diameter, segmented insulators samples in a vacuum to evaluate the multi-layer surface dielectric strength of the sample construction. Resonances in the low inductance test geometry were used to obtain unipolar, pulsed electric fields in excess of 100 MV/m on the insulator surface. The sample construction, experimental arrangement and experimental results are presented for the initial data in this work. Modeling of the multi-layer structure is discussed and methods of improving insulator surface dielectric strength in a vacuum are proposed.

The conceptual design of an Radioisotope Thermoelectric Generator (RTG) Facility Transportation System which is part of the overall RTG Transportation System has been completed and is described in detail. The Facility Transportation System serves to provide locomotion, cooling, shock protection and data acquisition for the RTG package during loading and unloading sequences. The RTG Facility Transportation System consists of a Transporter Subsystem, a Package Cooling Subsystem, and a Shock Limiting Transit Device Subsystem. The Transporter Subsystem is a uniquely designed welded steel cart combined with a pneumatically-driven hand tug for locomotion. The Package Cooling Subsystem provides five kilowatts of active liquid cooling via an on-board refrigeration system. The Shock limiting Transit Device Subsystem consists of a consumable honeycomb transit frame which provides shock protection for the 3855 kg (8500 LB) RTG package. These subsystems have been combined into an integrated system which will facilitate the unloading and loading of the RTG , of the Transport Trailer as well as meet ALARA radiation Package into and out exposure guidelines.

We present results from searches for top quark production in p{bar p} collisions at the Tevatron collider based on an integrated luminosity of 7.5 pb{sup {minus}1} obtained during the 1992--1993 ran. The present results are confined to decay modes where both the top and anti-top quarks in the event decay semi-leptonically to the ee and e{mu} channels. A lower limit of 103 (99) GeV/c{sup 2} is obtained at 95% confidence level for the top quark mass from the absence of events consistent with standard model top quark decays with background subtraction (no background subtraction). We do however observe one event in the e{mu} channel which cannot be explained by the known backgrounds. While we make no claim that this event is due to top quark decay, it is not inconsistent with a top quark mass in the range 130--170 GeV/c{sup 2}

This paper presents scaling results based on simulations with the CALE hydrodynamics code of aluminum projectile impacts on typical aluminum Whipple shields at speeds of 6 to 14 km/s. The objective was to determine the extent of projectile and target material melting. The approach was to perform a matrix of computer simulations varying the impact speed from 6 to 14 km/s and varying the areal density of the shield from 5 percent to 80 percent of the centerline areal density of the projectile. The projectile radius was fixed at 9.5 mm (mass = 1.27 grams). The melt state of the projectile material and the shield material was assessed after release of the initial shock. The post-release specific energy in the projectile and in the shield was compared with the enthalpy of incipient melt and the enthalpy of complete melt provided in the Hultgren Tables. Material with specific energy greater than the enthalpy of complete melt was assumed to be fully melted; material with specific energy greater than the enthalpy of incipient melt but less than that of complete melt was assumed to be partially solid and partially melted mixed phase material with no strength; and material with specific energy less …

During the next two years, the Fermilab Tavatron is expected to deliver approximately 100pb{sup {minus}1} of integrated luminosity. We describe improvements to the CDF detector since the 1988--89 collider run and discuss the prospects for the discovery of the top quark during the 1992--93 collider runs.