This article is about how the reaction of N20 with O is a key step in consumption of nitrous oxide in thermal processes. In the present work ,the authors re-examined a wide range of experiments relevant for the N2O+O reaction through kinetic modeling, paying attention to the impact of artifacts such as impurities and surface reactions.

Article describes how connecting organic building blocks by covalent bonds to design porous crystalline networks has led to covalent organic frameworks (COFs), consequently transferring the flexibility of dynamic linkages from discrete architectures to extended structures. Authors state that this review article highlights the fundamental of COFs, including designing principles, coupling reactions, topologies, structural diversity, synthetic strategies, characterization, growth mechanism, and activation aspects of COFs.

Article discusses how, in the era of intelligent applications, Mobile Edge Computing (MEC) is emerging as a promising technology that provides abundant resources for mobile devices. The authors of the article introduce a novel Device-to-Device (D2D)-assisted system to address this challenge.

Article states that the development of efficient heterogeneous catalysts with multiselectivity (e.g., enantio- and chemoselectivity) has long been sought after but with limited progress being made so far. To achieve enantio- and chemoselectivity in a heterogeneous system, as inspired by enzymes, the authors illustrate herein an approach of creating an enzyme-mimic region (EMR) within the nanospace of a metal–organic framework (MOF) as exemplified in the context of incorporating a chiral frustrated Lewis pair (CFLP) into a MOF with a tailored pore environment.

Article examining the influence of six goal orientations on physical activity (PA) and physical fitness (PF) in high school students in China using the latest 3 × 2 achievement goal model. Results show fostering self- and other-approach-oriented environments with developmentally appropriate content in physical education may have implications for enhancing high school students’ PA and PF.

Article focusing on West Nile Virus (WNV), a mosquito borne pathogen, as a case study for spatial data visualization of environmental characteristics of a vector’s habitat alongside human demographic composition for understanding potential public health risks of infectious disease.

Article identifying novel epigenetic regulators for tfpia and exploiting this information to discover a drug that enhances tfpia mRNA levels and prolongation of TTO. This discovery provides the basis for testing whether UNC6852 could be used as an antithrombotic drug.

Large aperture, beryllium substrate-based mirrors have been used to focus high intensity pulsed laser beams. Finished surfaces have high reflectivity, low wavefront distortion, and high laser damage thresholds. This paper describes the development of a series of metallic coatings, surface finishing techniques, and dielectric overcoatings to meet specified performance requirements. Beryllium substrates were coated with copper, diamond-machined to within 5 micro-inches to final contour, nickel plated, and abrasively figured to final contour. Bond strengths for several bonding processes are presented. Dielectric overcoatings were deposited on finished multimetallic substrates to increase both reflectivity and the damage thresholds. Coatings were deposited using both high and low temperature processes which induce varying stresses in the finished coating substrate system. Data are presented to show the evolution of wavefront distortion, reflectivity, and damage thresholds throughout the many steps involved in fabrication.

The geometry and size of the superconducting coils for the Mirror Fusion Test Facility (MFTF) proposed by Lawrence Livermore Laboratory (LLL) impose certain constraints on the Nb-Ti superconductor. The most promising fabrication process is a wrap-around technique in which a superconducting core is ''wrapped'' in stabilizing copper that contains built-in cooling channels. Insulation between pancake coils and turns is provided by perforated sheets and buttons of epoxy-impregnated fiberglass. Preliminary heat-transfer tests conducted on short samples of single conductor and on a nine-conductor bundle are reported and related to the heat generated in ''normal'' conductors. Investigation of joining techniques, necessary because of the length of conductor needed for the MFTF magnet (about 21 km per coil), show that cold-welded butt joints best meet all requirements. In a test coil now being built, approximately 2 km of prototype MFTF conductor will provide a self-field of about 4 T. Supplementary coils will boost the field to about 6.7 T. The test coils will be used to study cryostatic stability, the propagation and recovery of normal zones, and diagnostic techniques.

A quasilinear model for the evolution of the 2XIIB mirror experiment is presented and shown to reproduce the time evolution of the experiment. From quasilinear theory it follows that the energy lifetime is the Spitzer electron drag time for T/sub e/ approximately less than 0.1T/sub i/. By computing the stability boundary of the DCLC mode, with warm plasma stabilization, the electron temperature is predicted as a function of radial scale length. In addition, the effect of finite length corrections to the Alfven cyclotron mode is assessed.

A theoretical model of afterburning in explosions created by turbulent mixing of the detonation products from fuel-rich charges with air is described. It contains three key elements: (i) a thermodynamic-equilibrium description of the fluids (fuel, air, and products), (ii) a multi-component gas-dynamic treatment of the flow field, and (iii) a sub-grid model of molecular processes of mixing, combustion and equilibration.

The National Nuclear Security Administration's (NNSA) Highly Enriched Uranium (HEU) Transparency Implementation Program (TIP) monitors and provides assurance that Russian weapons-grade HEU is processed into low enriched uranium (LEU) under the transparency provisions of the 1993 United States (U.S.)-Russian HEU Purchase Agreement. Meeting the Agreement's transparency provisions is not just a program requirement; it is a legal requirement. The HEU Purchase Agreement requires transparency measures to be established to provide assurance that the nonproliferation objectives of the Agreement are met. The Transparency concept has evolved into a viable program that consists of complimentary elements that provide necessary assurances. The key elements include: (1) monitoring by technical experts; (2) independent measurements of enrichment and flow; (3) nuclear material accountability documents from Russian plants; and (4) comparison of transparency data with declared processing data. In the interest of protecting sensitive information, the monitoring is neither full time nor invasive. Thus, an element of trust is required regarding declared operations that are not observed. U.S. transparency monitoring data and independent instrument measurements are compared with plant accountability records and other declared processing data to provide assurance that the nonproliferation objectives of the 1993 Agreement are being met. Similarly, Russian monitoring of U. S. …

The end of the Cold War allows a comprehensive assessment of the nature and extent of the residual contamination derivative from the atomic defense and nuclear power enterprise in the former Soviet Union. The size of the problem is considerable; some 6.3 x 10{sup 7} TBq (6.4 x 10{sup 8} m{sup 3}) of radioactive waste from the Soviet Union weapons and power complex was produced throughout all stages of the nuclear fuel cycle. The resulting contamination occurs at sites throughout the former Soviet Union where nuclear fuels were mined, milled, enriched, fabricated, and used in defense and power reactors. In addition, liquid radioactive wastes from nuclear reprocessing have been discharged to lakes, rivers, reservoirs and other surface impoundments; military and civilian naval reactor effluents were released to sea as well as stabilized on land. Finally, nuclear testing residuals from atmospheric and underground nuclear tests at the Semipalatinsk and Novaya Zemlya test sites and peaceful nuclear tests conducted throughout the area of the former Soviet Union pose risks to human health and the environment. Through a program of international scientific exchange, cooperative approaches to address these threats provide former Soviet scientists with expertise and technologies developed in the United States, Europe, …

The monitoring of nuclear explosions on a global basis requires accurate event locations. As an example, a typical size used for an on-site inspection search area is 1,000 square kilometers or approximately 17 km accuracy, assuming a circular area. This level of accuracy is a significant challenge for small events that are recorded using a sparse regional network. In such cases, the travel time of seismic energy is strongly affected by crustal and upper mantle heterogeneity and large biases can result. This can lead to large systematic errors in location and, more importantly, to invalid error bounds associated with location estimates. Calibration data and methods are being developed and integrated to correct for these biases. Our research over the last few years has shown that one of the most effective approaches to generate path corrections is the hybrid technique that combine both regionalized models with three-dimensional empirical travel-time corrections. We implement a rigorous and comprehensive uncertainty framework for these hybrid approaches. Qualitative and quantitative validations are presented in the form of single component consistency checks, sensitivity analysis, robustness measures, outlier testing along with end-to-end testing of confidence measures. We focus on screening and validating both empirical and model based calibrations …

Understanding numerical errors in long calculations is a very subtle science and is critical to understanding the reliability of the final answer. We will carefully examine the accumulation of numerical errors over time and discuss how these can lead to reliability estimates. The primary focus will be on a newly uncovered understanding of mode resolution which is at the heart of all numerical computations.

Nucleation-growth kinetic expressions are derived for thermal decomposition of HMX from a variety of types of data, including mass loss for isothermal and constant rate heating in an open pan, and heat flow for isothermal and constant rate heating in open and closed pans. Conditions are identified in which thermal runaway is small to nonexistent, which typically means temperatures less than 255 C and heating rates less than 1 C/min. Activation energies are typically in the 140 to 150 kJ/mol regime for open pan experiments and about 160 kJ/mol for sealed pan experiments. The reaction clearly displays more than one process, and most likely three processes, which are most clearly evident in open pan experiments. The reaction is accelerated for closed pan experiments, and one global reaction appears to fit the data well.

LLNL identification research is focused on the problem of correctly discriminating small-magnitude explosions from a background of earthquakes, mining tremors, and other events. The goal is to reduce the variance within the population of each type of event, while increasing the separation between the explosions and the other event types. We address this problem for both broad categories of seismic waves: body waves and surface waves. First, we map out the effects of propagation and source size in advance so that they can be accounted for and removed from observed events. This can dramatically reduce the population variance. Second, we try to optimize the measurement process to improve the separation between population types. For body waves we focus on the identification power of the short-period regional phases Pn, Pg, Sn and Lg, which can often be detected down to very small magnitudes. Many studies have shown that particular ratios of these phases, such as 6-to 8-Hz Pn/Lg, can effectively discriminate between closely located explosions and earthquakes. To extend this discrimination power over broad areas, we use our revised Magnitude and Distance Amplitude Correction (MDAC2) procedure. This joint source and path model fits the observed spectra and removes magnitude and distance …

The National Ignition Facility (NIF) is an inertial confinement fusion project being built at Lawrence Livermore National Laboratory (LLNL) for the Department of Energy (DOE). The project is comprised of two buildings and the high technology equipment. The NIF houses 192 separate laser beams that generate approximately two megajoules of energy and 500 terawatts of power. The laser beams travel through a large optical system that contains over 7,500 large-aperture optical components (40 cm by 40 cm) and approximately 30,000 small-aperture optical components (less than 20 cm diameter). The NIF laser will be enclosed in a building that is approximately 200 meters in length (l) by 100 meters in width (w) by 15 meters in height (h) scheduled for completion by the end of 2002. A 0.5 mm target will be positioned inside a 10 meter sphere in the Target Building which measures approximately 35 meters (l) by 90 meters (w) by 30 meters (h). To achieve optimum laser operation the optics will require precision positioning and alignment. As a result, the mechanical components that support the optics require accurate positioning. State-of-the-art surveying, measuring techniques, and uncertainty and error analyses are being used to measure the control network and mechanical …

The technique of using a nsec pulse to preform and ionize the plasma followed by a psec pulse to heat the plasma has enabled low-Z nickel-like ions to achieve saturated output when driven by small lasers with less than ten joules of energy. We model experiments done using the COMET laser at LLNL and the P 102 laser at Limeil to produce Ni-like Pd and Ag lasers. The COMET experiments use a 2 J, 600 ps prepulse followed 700 psec later by a 6 J, 6 psec drive pulse in a 1.6 cm long line focus. The P102 experiments used a somewhat larger energy and were able to use different combinations of frequency doubled light for both the prepulse and short pulse drive. The LASNEX code is used to calculate the hydrodynamic evolution of the plasma and provide the temperatures and densities to the CRETIN code, which then does the kinetics calculations to determine the gain. The temporal and spatial evolution of the plasmas are studied both with and without radiation transport included to understand the role of the self photopumping process on the gain of the Ni-like 4f {yields} 4d laser lines as well as the gain of the …

This paper describes experimental results and numerical simulations of jet penetration into granite from an aluminum lined shaped charge. Several penetration versus standoff experiments were conducted into an in-situ granite formation located in the Climax Ridge region of the Nevada Test Site. Simulations of the jet penetration were modeled with a two dimensional arbitrary lagrange eulerian hydrocode. The effects of variations in the granite flow stress, porosity, and EOS have been evaluated. The work described in this paper is a continuation of our studies on jet penetration and modeling into high strength concrete.

We use regional waveform data from the Nevada Test Site (NTS) to investigate phenomenological relationships between recorded amplitude and explosion yield as well as test regional depth estimation procedures. Our goal is to better understand the performance of seismic observables in other regions of monitoring interest, especially at small magnitudes (m{sub b}<<4.5). Some of the topics we are studying include: stable yield estimation, depth estimation, and M{sub g}:m{sub b} performance. We use Lawrence Livermore National Laboratory's NTS explosion database, which consists of several hundred events ranging from {approx}200 to {approx}1500-m depth and yields ranging from a few tenths of a kiloton to the megaton range. In addition to the broadband explosion data, we have a large dataset of well-located earthquakes on the test site with depths ranging from 2 to 17 km and magnitudes ranging between M{sub w}1.5 and 5.7. For yield estimation the relation between teleseismic body wave magnitude (mb) and nuclear explosion yield has been studied extensively over the past several decades for a number of test sites for large (>1 kt) explosions. In this paper we will look at broadband coda, P{sub g,} and L{sub g} from over 260 nuclear explosions to study yield estimation capability by …

None

High-power copper vapor lasers (CVLs) have been under development at Lawrence Livermore National Laboratory (LLNL) for more than 15 years in support of the DOE`s Program in Laser Isotope Separation. The technology is now quite mature, having met many of its goals in system architecture, power, reliability, and maintainability. Over the past several years we have begun an effort to utilize this technology in other industrial applications, such as metals processing, and have found a number of unique processes. In this paper we describe briefly the general characteristics of the CVL, our recent progress in developing the laser as an industrial tool, and our progress in using the laser in precision drilling and cutting.

This paper shows an analysis of the applicability of an adsorption system for electric vehicle (EV) air conditioning. Adsorption systems are designed and optimized to provide the required cooling for four combinations of vehicle characteristics and driving cycles. The resulting adsorption systems are compared with vapor compression air conditioners that can satisfy the cooling load. The objective function is the overall system weight, which includes the cooling system weight and the weight of the battery necessary to provide energy for air conditioner operation. The system with the minimum overall weight is considered to be the best. The results show the optimum values of all the variables, as well as temperatures and amounts adsorbed, for the adsorption and desorption processes. The results indicate that, for the conditions analyzed in this paper, vapor compression air conditioners are superior to adsorption systems, not only because they are lighter, but also because they have a higher COP and are more compact.