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in creator/contributor: "Johnson, N."

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Nonlinear Legendre Spectral Finite Elements for Wind Turbine Blade Dynamics: Preprint

This paper presents a numerical implementation and examination of new wind turbine blade finite element model based on Geometrically Exact Beam Theory (GEBT) and a high-order spectral finite element method. The displacement-based GEBT is presented, which includes the coupling effects that exist in composite structures and geometric nonlinearity. Legendre spectral finite elements (LSFEs) are high-order finite elements with nodes located at the Gauss-Legendre-Lobatto points. LSFEs can be an order… more

Date: January 1, 2014

Creator: Wang, Q.; Sprague, M. A.; Jonkman, J. & Johnson, N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

DUAL Gamma-Ray Mission

No Description Available.

Date: June 21, 2013

Creator: Boggs, S.; Wunderer, C.; von Ballmoos, P.; Takahashi, T.; Gehrels, N.; Tueller, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

[sup 3]He neutron detector performance in mixed neutron gamma environments

A test program of the performance of 3He neutron proportional detectors with varying gas pressures, and their response to lligh level gamma-ray exposure in a mixed neutrodgamma environment, ha$ been performed Our intent was to identie the optimal gas pressure to reduce the gamma-ray sensitivity of these detectors. These detectors were manufxtured using materials to minimize their gamma response. Earlier work focused on 3He fill pressures of four atmospheres and above, whereas the present work f… more

Date: January 1, 2002

Creator: Johnson, N. H. (Nathan H.) & Beddingfield, D. H. (David H.)

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A holistic look at minimizing adverse environmental impact under section 316(b) of the clean water act.

No Description Available.

Date: August 14, 2001

Creator: Veil, J. A.; Puder, M. G.; Littleton, D. J. & Johnson, N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

OUT Success Stories: Solar Roofing Shingles

Thin-film photovoltaic (PV) cells are now doubling as rooftop shingles. PV shingles offer many advantages. The energy generated from a building's PV rooftop shingles can provide power both to the building and the utility's power grid.

Date: August 31, 2000

Creator: Johnson, N.

Item Type: Book

Partner: UNT Libraries Government Documents Department

open access

DEVELOPMENT INSIGHTS INTO EVOLVING SYSTEMS: ROLES OF DIVERSITY, NON-SELECTION, SELF-ORGANIZATION, SYMBIOSIS

No Description Available.

Date: February 1, 2000

Creator: Johnson, N. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Symbiotic intelligence: Self-organizing knowledge on distributed networks, driven by human interaction

This work addresses how human societies, and other diverse and distributed systems, solve collective challenges that are not approachable from the level of the individual, and how the Internet will change the way societies and organizations view problem solving. The authors apply the ideas developed in self-organizing systems to understand self-organization in informational systems. The simplest explanation as to why animals (for example, ants, wolves, and humans) are organized into societies i… more

Date: July 1, 1998

Creator: Johnson, N.; Joslyn, C.; Rocha, L.; Smith, S.; Kantor, M. & Rasmussen, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Analecta of structures formed during the 28 June 1992 Landers-Big Bear, California earthquake sequence (including maps of shear zones, belts of shear zones, tectonic ridge, duplex en echelon fault, fault elements, and thrusts in restraining steps)

The June 28, 1992, M{sub s} 7.5 earthquake at Landers, California, which occurred about 10 km north of the community of Yucca Valley, California, produced spectacular ground rupturing more than 80 km in length (Hough and others, 1993). The ground rupturing, which was dominated by right-lateral shearing, extended along at least four distinct faults arranged broadly en echelon. The faults were connected through wide transfer zones by stepovers, consisting of right-lateral fault zones and tension … more

Date: December 31, 1997

Creator: Johnson, A.M.; Johnson, N.A.; Johnson, K.M.; Wei, W.; Fleming, R.W.; Cruikshank, K.M. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Hydrogen as a zero-emission, high-efficiency fuel: Uniqueness, experiments and simulations

The planned use of hydrogen as the energy carrier of the future introduces new challenges and opportunities, especially to the engine design community. Hydrogen is a bio-friendly fuel that can be produced from renewable resources and has no carbon dioxide combustion products; and in a properly designed ICE, almost zero NO{sub x} and hydrocarbon emissions can be achieved. Because of the unique properties of hydrogen combustion - in particular the highly wrinkled nature of the laminar flame front… more

Date: November 1, 1997

Creator: Johnson, N. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Numerical modeling of hydrogen-fueled internal combustion engines

Date: December 31, 1996

Creator: Johnson, N. L. & Amsden, A. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Computer modeling in the design and evaluation of electric and hybrid vehicles

This demonstration project uses modern simulation techniques to illustrate the important technologies and design variables that an auto-designer would consider in production a high efficiency, low emissions vehicle. Simulation and modeling techniques use the idea of capturing the relationships between real components of the systems with mathematical equations. These equations are then solved on a computer to simulate the behavior or performance of the system under various conditions. In the cur… more

Date: August 16, 1996

Creator: Aceves, S. M.; Smith, J. R. & Johnson, N. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Numerical modeling of hydrogen-fueled internal combustion engines

Major progress was achieved in the last year in advancing the modeling capabilities of hydrogen-fueled engines, both in support of the multi-laboratory project with SNL and LLNL to develop a high-efficiency, low emission powerplant and to provide the engine design tools to industry and research laboratories for hydrogen-fueled engines and stationary power generators. The culmination of efforts on many fronts was the excellent comparison of the experimental data from the Onan engine, operated by… more

Date: July 1, 1996

Creator: Johnson, N. L.; Amsden, A. A. & Butler, T. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The legacy and future of CFD at Los Alamos

The early history is presented of the prolific development of CFD methods in the Fluid Dynamics Group (T-3) at Los Alamos National Laboratory in the years from 1958 to the late 1960`s. Many of the currently used numerical methods--PIC, MAC, vorticity-stream-function, ICE, ALE methods and the {kappa}-{var_epsilon} method for turbulence--originated during this time. The rest of the paper summarizes the current research in T-3 for CFD, turbulence and solids modeling. The research areas include rea… more

Date: June 1, 1996

Creator: Johnson, N. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Research on the stability, electronic properties, and structure of a-Si:H and its alloys. Final subcontract report, 1 June 1991--31 May 1994

The authors research has focused on defect metastability and a-Si:C:H alloys. A new aspect of the metastability is the growing interest in the defect recovery process. They have continued to explore the role of hydrogen in the metastability and other properties of a-Si:H. This has led them to perform first principles calculations of Si-H bonding configurations. Another new feature of the metastability work is the study of the effects in hydrogenated poly-silicon. They have grown and studied the… more

Date: July 1, 1995

Creator: Jackson, W.B.; Johnson, N.; Nickel, N.; Schumm, G.; Street, R.A.; Thompson, R. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Progress toward an optimized hydrogen series hybrid engine

The design considerations and computational fluid dynamics (CFD) modeling of a high efficiency, low emissions, hydrogen-fueled engine for use as the prime mover of a series hybrid automobile is described. The series hybrid automobile uses the engine to generate electrical energy via a lightweight generator, the electrical energy is stored in a power peaking device (like a flywheel or ultracapacitor) and used as required to meet the tractive drive requirements (plus accessory loads) through an e… more

Date: June 1, 1995

Creator: Smith, J. R.; Aceves, S. M.; Johnson, N. L. & Amsden, A. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Hydrogen program combustion research: Three dimensional computational modeling

We have significantly increased our computational modeling capability by the addition of a vertical valve model in KIVA-3, code used internationally for engine design. In this report the implementation and application of the valve model is described. The model is shown to reproduce the experimentally verified intake flow problem examined by Hessel. Furthermore, the sensitivity and performance of the model is examined for the geometry and conditions of the hydrogen-fueled Onan engine in developm… more

Date: May 1, 1995

Creator: Johnson, N. L.; Amsden, A. A. & Butler, T. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Three-dimensional computer modeling of hydrogen injection and combustion

The hydrodynamics of hydrogen gas injection into a fixed-volume combustion chamber is analyzed and simulated using KIVA-3, a three-dimensional, reactive flow computer code. Comparisons of the simulation results are made to data obtained at the Combustion Research Facility at Sandia National Laboratory-California (SNL-CA). Simulation of the gas injection problem is found to be of comparable difficulty as the liquid fuel injection in diesel engines. The primary challenge is the large change of le… more

Date: February 1, 1995

Creator: Johnson, N. L.; Amsden, A. A.; Naber, J. D. & Siebers, D. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Research on the stability, electronic properties, and structure of a-Si:H and its alloys. Annual subcontract report, 1 June 1992--31 May 1993

This report describes work focusing on the defect and transport properties of a-Si:H with particular emphasis on defect metastability. Light-induced defects remain the major impediment to higher stabilized solar cell efficiencies. The many years of research have shown that this is a difficult problem to solve, and we take the view that a solution can be found only with a deep understanding of the mechanism; this has been our main goal. The metastability is closely related to the intrinsic defec… more

Date: February 1, 1994

Creator: Jackson, W. B.; Johnson, N. & Nickel, N.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Equilibrium ignition for ICF capsules

There are two fundamentally different approaches to igniting DT fuel in an ICF capsule which can be described as equilibrium and hot spot ignition. In both cases, a capsule which can be thought of as a pusher containing the DT fuel is imploded until the fuel reaches ignition conditions. In comparing high-gain ICF targets using cryogenic DT for a pusher with equilibrium ignition targets using high-Z pushers which contain the radiation. The authors point to the intrinsic advantages of the latter.… more

Date: December 31, 1993

Creator: Lackner, K. S.; Colgate, S. A.; Johnson, N. L.; Kirkpatrick, R. C.; Menikoff, R. & Petschek, A. G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Nonlocal models in continuum mechanics

The recent appearance of nonlocal methods is examined in the light of traditional continuum mechanics. A comparison of nonlocal approaches in the fields of solid and fluid mechanics reveals that no consistent definition of a nonlocal theory has been used. We suggest a definition based on the violation of the principle of local action in continuum mechanics. From the consideration of the implications of a nonlocal theory based on this definition, we conclude that constitutive relations with nonl… more

Date: September 1, 1993

Creator: Johnson, N. L. & Phan-Thien, N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

High spin states in neutron rich nuclei from spontaneous fission

One fragment-{gamma}-{gamma} and three {gamma}-{gamma} coincidence measurements of the prompt {gamma}-rays from the fragments produced in the spontaneous fission (SF) of {sup 252}Cf and very recently of {sup 242}Pu were carried out with a 20 Ge detector ball at HHIRF. With our high statistics, {gamma}-{gamma}-{gamma} coincidences where the two gates are on transitions in the two partner fragments were extracted. Comparing the {sup 252}Cf and {sup 242}Pu data allowed unique placements of many tr… more

Date: December 31, 1992

Creator: Butler-Moore, K.; Zhu, S.; Zhao, X.; Hamilton, J. H.; Ramayya, A. V.; Lu, Q. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Research on the stability, electronic properties, and structure of a-Si:H and its alloys

Objective is to obtain a comprehensive understanding of structure and electronic properties of a-Si:H as they apply to solar cells. First observations were of light enhancement and field suppression of H diffusion in a-Si:H. Theoretical studies were made of hydrogen density of states distribution and its relation to defect metastability. Reduced density of light induced defect is observed in a-Si:H deposited in a remote hydrogen plasma reactor at 400 C. Kinetics of metastable defect creation us… more

Date: December 1, 1992

Creator: Street, R. A.; Jackson, W. B.; Johnson, N.; Nebel, C.; Hack, M.; Santos, P. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Further comments about B-physics in pp interactions

We summarize discussions concerning the study of B-physics at the SSC. Different approaches are considered. The first one corresponds to the collider experiments detecting charged particles with pseudo-rapidity of {vert_bar}{eta}{vert_bar}{le} 2.4 whereas the second method considers the detection of B-mesons in the forward/backward directions. The utilization of external or gas-jet targets are also briefly discussed.

Date: June 1, 1992

Creator: Botlo, M.; Coupal, D.: Dorenbosch, J.; Siegrist, J.; Wang, E.; Fridman, A.; Shapiro, S. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

The role of cellular and molecular studies in evaluation of health effects from combined radiation and chemical exposures

Additive models are currently used to predict risks following exposure to multiple agents or complex mixtures. Use of these models is questioned because different methods are used to derive risks for chemical and physical agents depending on the database used. Risks for the induction of cancer from radiation are based on large sets of human data, while standards are set for most chemical carcinogens using information derived from animal studies. However, it is not, from a scientific point of vi… more

Date: June 1, 1992

Creator: Brooks, A. L.; Gilbert, E. S.; Kitchin, R. M. & Johnson, N. F.

Item Type: Article

Partner: UNT Libraries Government Documents Department