Band Structures and Transport Properties of High-Performance Half-Heusler Thermoelectric Materials by First Principles.

PubMed

Fang, Teng; Zhao, Xinbing; Zhu, Tiejun

2018-05-19

Half-Heusler (HH) compounds, with a valence electron count of 8 or 18, have gained popularity as promising high-temperature thermoelectric (TE) materials due to their excellent electrical properties, robust mechanical capabilities, and good high-temperature thermal stability. With the help of first-principles calculations, great progress has been made in half-Heusler thermoelectric materials. In this review, we summarize some representative theoretical work on band structures and transport properties of HH compounds. We introduce how basic band-structure calculations are used to investigate the atomic disorder in n-type M NiSb ( M = Ti, Zr, Hf) compounds and guide the band engineering to enhance TE performance in p-type Fe R Sb ( R = V, Nb) based systems. The calculations on electrical transport properties, especially the scattering time, and lattice thermal conductivities are also demonstrated. The outlook for future research directions of first-principles calculations on HH TE materials is also discussed.

Band Structures and Transport Properties of High-Performance Half-Heusler Thermoelectric Materials by First Principles

PubMed Central

Fang, Teng; Zhao, Xinbing

2018-01-01

Half-Heusler (HH) compounds, with a valence electron count of 8 or 18, have gained popularity as promising high-temperature thermoelectric (TE) materials due to their excellent electrical properties, robust mechanical capabilities, and good high-temperature thermal stability. With the help of first-principles calculations, great progress has been made in half-Heusler thermoelectric materials. In this review, we summarize some representative theoretical work on band structures and transport properties of HH compounds. We introduce how basic band-structure calculations are used to investigate the atomic disorder in n-type MNiSb (M = Ti, Zr, Hf) compounds and guide the band engineering to enhance TE performance in p-type FeRSb (R = V, Nb) based systems. The calculations on electrical transport properties, especially the scattering time, and lattice thermal conductivities are also demonstrated. The outlook for future research directions of first-principles calculations on HH TE materials is also discussed. PMID:29783759

Principles for high-quality, high-value testing.

PubMed

Power, Michael; Fell, Greg; Wright, Michael

2013-02-01

A survey of doctors working in two large NHS hospitals identified over 120 laboratory tests, imaging investigations and investigational procedures that they considered not to be overused. A common suggestion in this survey was that more training was required. And, this prompted the development of a list of core principles for high-quality, high-value testing. The list can be used as a framework for training and as a reference source. The core principles are: (1) Base testing practices on the best available evidence. (2) Apply the evidence on test performance with careful judgement. (3) Test efficiently. (4) Consider the value (and affordability) of a test before requesting it. (5) Be aware of the downsides and drivers of overdiagnosis. (6) Confront uncertainties. (7) Be patient-centred in your approach. (8) Consider ethical issues. (9) Be aware of normal cognitive limitations and biases when testing. (10) Follow the 'knowledge journey' when teaching and learning these core principles.

Whole School Improvement and Restructuring as Prevention and Promotion: Lessons from STEP and the Project on High Performance Learning Communities.

ERIC Educational Resources Information Center

Felner, Robert D.; Favazza, Antoinette; Shim, Minsuk; Brand, Stephen; Gu, Kenneth; Noonan, Nancy

2001-01-01

Describes the School Transitional Environment Project and its successor, the Project on High Performance Learning Communities, that have contributed to building a model for school improvement called the High Performance Learning Communities. The model seeks to build the principles of prevention into whole school change. Presents findings from…

Time–temperature superposition principle applied to a kenaf-fiber/high-density polyethylene composite

Treesearch

Mehdi Tajvidi; Robert H. Falk; John C. Hermanson

2005-01-01

The time–temperature superposition principle was applied to the viscoelastic properties of a kenaf- fiber/high-density polyethylene (HDPE) composite, and its validity was tested. With a composite of 50% kenaf fibers, 48% HDPE, and 2% compatibilizer, frequency scans from a dynamic mechanical analyzer were performed in the range of 0.1–10 Hz at five different...

48 CFR 36.104 - Policy.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Guiding Principles for Federal Leadership in High-Performance and Sustainable Buildings (available at http://www.wbdg.org/pdfs/hpsb_guidance.pdf); (2) Pursue cost-effective, innovative strategies, such as highly...

High-Performance Solid-State Thermionic Energy Conversion Based on 2D van der Waals Heterostructures: A First-Principles Study.

PubMed

Wang, Xiaoming; Zebarjadi, Mona; Esfarjani, Keivan

2018-06-18

Two-dimensional (2D) van der Waals heterostructures (vdWHs) have shown multiple functionalities with great potential in electronics and photovoltaics. Here, we show their potential for solid-state thermionic energy conversion and demonstrate a designing strategy towards high-performance devices. We propose two promising thermionic devices, namely, the p-type Pt-G-WSe 2 -G-Pt and n-type Sc-WSe 2 -MoSe 2 -WSe 2 -Sc. We characterize the thermionic energy conversion performance of the latter using first-principles GW calculations combined with real space Green's function (GF) formalism. The optimal barrier height and high thermal resistance lead to an excellent performance. The proposed device is found to have a room temperature equivalent figure of merit of 1.2 which increases to 3 above 600 K. A high performance with cooling efficiency over 30% of the Carnot efficiency above 450 K is achieved. Our designing and characterization method can be used to pursue other potential thermionic devices based on vdWHs.

Launch vehicle systems design analysis

NASA Technical Reports Server (NTRS)

Ryan, Robert; Verderaime, V.

1993-01-01

Current launch vehicle design emphasis is on low life-cycle cost. This paper applies total quality management (TQM) principles to a conventional systems design analysis process to provide low-cost, high-reliability designs. Suggested TQM techniques include Steward's systems information flow matrix method, quality leverage principle, quality through robustness and function deployment, Pareto's principle, Pugh's selection and enhancement criteria, and other design process procedures. TQM quality performance at least-cost can be realized through competent concurrent engineering teams and brilliance of their technical leadership.

Energy Design Guidelines for High Performance Schools: Temperate and Humid Climates.

ERIC Educational Resources Information Center

Department of Energy, Washington, DC. Office of Energy Efficiency and Renewable Energy.

The U.S. Department of Energy's EnergySmart Schools provides school boards, administrators, and design staff with guidance to help them make informed decisions about energy and environmental issues important to school systems and communities. The design guidelines presented in this document outline high performance principles for the new or…

Energy Design Guidelines for High Performance Schools: Hot and Humid Climates.

ERIC Educational Resources Information Center

National Renewable Energy Lab. (DOE), Golden, CO.

The U.S. Department of Energy's EnergySmart Schools provides school boards, administrators, and design staff with guidance to help them make informed decisions about energy and environmental issues important to school systems and communities. The design guidelines presented in this document outline high performance principles for the new or…

Energy Design Guidelines for High Performance Schools: Cool and Humid Climates.

ERIC Educational Resources Information Center

National Renewable Energy Lab. (DOE), Golden, CO.

The U.S. Department of Energy's EnergySmart Schools provides school boards, administrators, and design staff with guidance to help them make informed decisions about energy and environmental issues important to school systems and communities. The design guidelines presented in this document outline high performance principles for the new or…

Energy Design Guidelines for High Performance Schools: Temperate and Mixed Climates.

ERIC Educational Resources Information Center

National Renewable Energy Lab. (DOE), Golden, CO.

The U.S. Department of Energy's EnergySmart Schools provides school boards, administrators, and design staff with guidance to help them make informed decisions about energy and environmental issues important to school systems and communities. The design guidelines presented in this document outline high performance principles for the new or…

Energy Design Guidelines for High Performance Schools: Cool and Dry Climates.

ERIC Educational Resources Information Center

National Renewable Energy Lab. (DOE), Golden, CO.

The U.S. Department of Energy's EnergySmart Schools provides school boards, administrators, and design staff with guidance to help them make informed decisions about energy and environmental issues important to school systems and communities. The design guidelines presented in this document outline high performance principles for the new or…

Energy Design Guidelines for High Performance Schools: Cold and Humid Climates.

ERIC Educational Resources Information Center

Department of Energy, Washington, DC. Office of Energy Efficiency and Renewable Energy.

The U.S. Department of Energy's EnergySmart Schools provides school boards, administrators, and design staff with guidance to help them make informed decisions about energy and environmental issues important to school systems and communities. The design guidelines presented in this document outline high performance principles for the new or…

Accelerating the discovery of hidden two-dimensional magnets using machine learning and first principle calculations

NASA Astrophysics Data System (ADS)

Miyazato, Itsuki; Tanaka, Yuzuru; Takahashi, Keisuke

2018-02-01

Two-dimensional (2D) magnets are explored in terms of data science and first principle calculations. Machine learning determines four descriptors for predicting the magnetic moments of 2D materials within reported 216 2D materials data. With the trained machine, 254 2D materials are predicted to have high magnetic moments. First principle calculations are performed to evaluate the predicted 254 2D materials where eight undiscovered stable 2D materials with high magnetic moments are revealed. The approach taken in this work indicates that undiscovered materials can be surfaced by utilizing data science and materials data, leading to an innovative way of discovering hidden materials.

Benefits of Carrier-Pocket Anisotropy to Thermoelectric Performance: The Case of p -Type AgBiSe 2

DOE PAGES

Parker, David S.; May, Andrew F.; Singh, David J.

2015-06-05

Here we study theoretically the effects of anisotropy on the thermoelectric performance of p-type AgBiSe 2. We present an apparent realization of the thermoelectric benefits of one-dimensional plate-like carrier pocket anisotropy in the valence band of this material. Based on first principles calculations we find a substantial anisotropy in the electronic structure, likely favorable for thermoelectric performance, in the valence bands of the hexagonal phase of the silver chalcogenide thermoelectric AgBiSe 2, while the conduction bands are more isotropic, and in our experiments do not attain high performance. AgBiSe 2 has already exhibited a ZT value of 1.5 in amore » high-temperature disordered fcc phase, but room-temperature performance has not been demonstrated. We develop a theory for the ability of anisotropy to decouple the density-of-states and conductivity effective masses, pointing out the influence of this effect in the high performance thermoelectrics Bi 2Te 3 and PbTe. From our first principles and Boltzmann transport calculations we find that p-type AgBiSe 2 has substantial promise as a room temperature thermoelectric, and estimate its performance.« less

Using Behavioral Economics to Design Physician Incentives That Deliver High-Value Care.

PubMed

Emanuel, Ezekiel J; Ubel, Peter A; Kessler, Judd B; Meyer, Gregg; Muller, Ralph W; Navathe, Amol S; Patel, Pankaj; Pearl, Robert; Rosenthal, Meredith B; Sacks, Lee; Sen, Aditi P; Sherman, Paul; Volpp, Kevin G

2016-01-19

Behavioral economics provides insights about the development of effective incentives for physicians to deliver high-value care. It suggests that the structure and delivery of incentives can shape behavior, as can thoughtful design of the decision-making environment. This article discusses several principles of behavioral economics, including inertia, loss aversion, choice overload, and relative social ranking. Whereas these principles have been applied to motivate personal health decisions, retirement planning, and savings behavior, they have been largely ignored in the design of physician incentive programs. Applying these principles to physician incentives can improve their effectiveness through better alignment with performance goals. Anecdotal examples of successful incentive programs that apply behavioral economics principles are provided, even as the authors recognize that its application to the design of physician incentives is largely untested, and many outstanding questions exist. Application and rigorous evaluation of infrastructure changes and incentives are needed to design payment systems that incentivize high-quality, cost-conscious care.

Going the Distance: Are There Common Factors in High Performance Distance Learning? Research Report.

ERIC Educational Resources Information Center

Hawksley, Rosemary; Owen, Jane

Common factors among high-performing distance learning (DL) programs were examined through case studies at 9 further education colleges and 2 nonsector organizations in the United Kingdom and a backup survey of a sample of 50 distance learners at 5 of the colleges. The study methodology incorporated numerous principles of process benchmarking. The…

Recent advances in high-performance fluorescent and bioluminescent RNA imaging probes.

PubMed

Xia, Yuqiong; Zhang, Ruili; Wang, Zhongliang; Tian, Jie; Chen, Xiaoyuan

2017-05-22

RNA plays an important role in life processes. Imaging of messenger RNAs (mRNAs) and micro-RNAs (miRNAs) not only allows us to learn the formation and transcription of mRNAs and the biogenesis of miRNAs involved in various life processes, but also helps in detecting cancer. High-performance RNA imaging probes greatly expand our view of life processes and enhance the cancer detection accuracy. In this review, we summarize the state-of-the-art high-performance RNA imaging probes, including exogenous probes that can image RNA sequences with special modification and endogeneous probes that can directly image endogenous RNAs without special treatment. For each probe, we review its structure and imaging principle in detail. Finally, we summarize the application of mRNA and miRNA imaging probes in studying life processes as well as in detecting cancer. By correlating the structures and principles of various probes with their practical uses, we compare different RNA imaging probes and offer guidance for better utilization of the current imaging probes and the future design of higher-performance RNA imaging probes.

The GATE Way to Equity.

ERIC Educational Resources Information Center

Belz, Helene F.

Systematic observations of thousands of high school students in the California Mentally Gifted Minors/Gifted and Talented Education programs identified five principles underlying the development of high level thinking skills in this population: (1) Exceptional performance on any criterion requires mutually reinforcing antecedents, the effects of…

Basic principles for rational design of high-performance nanostructured silicon-based thermoelectric materials.

PubMed

Yang, Chun Cheng; Li, Sean

2011-12-23

Recently, nanostructured silicon-based thermoelectric materials have drawn great attention owing to their excellent thermoelectric performance in the temperature range around 450 °C, which is eminently applicable for concentrated solar thermal technology. In this work, a unified nanothermodynamic model is developed to investigate the predominant factors that determine the lattice thermal conductivity of nanocrystalline, nanoporous, and nanostructured bulk Si. A systematic study shows that the thermoelectric performance of these materials can be substantially enhanced by the following three basic principles: 1) artificial manipulation and optimization of roughness with surface/interface patterning/engineering; 2) grain-size reduction with innovative fabrication techniques in a controllable fashion; and 3) optimization of material parameters, such as bulk solid-vapor transition entropy, bulk vibrational entropy, dimensionality, and porosity, to decrease the lattice thermal conductivity. These principles may be used to rationally design novel nanostructured Si-based thermoelectric materials for renewable energy applications. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Behavioral and biological interactions with small groups in confined microsocieties

NASA Technical Reports Server (NTRS)

Brady, Joseph V.

1986-01-01

Research on small group performance in confined microsocieties was focused upon the development of principles and procedures relevant to the selection and training of space mission personnel, upon the investigation of behavioral programming, preventive monitoring and corrective procedures to enhance space mission performance effectiveness, and upon the evaluation of behavioral and physiological countermeasures to the potentially disruptive effects of unfamiliar and stressful environments. An experimental microsociety environment was designed and developed for continuous residence of human volunteers over extended time periods. Studies were then undertaken to analyze experimentally: (1) conditions that sustain group cohesion and productivity and that prevent social fragmentation and performance deterioration, (2) motivational effects performance requirements, and (3) behavioral and physiological effects resulting from changes in group size and composition. The results show that both individual and group productivity can be enhanced under such conditions by the direct application of contingency management principles to designated high-value tasks. Similarly, group cohesiveness can be promoted and individual social isolation and/or alienation prevented by the application of contingency management principles to social interaction segments of the program.

Jack of all trades masters novel host plants: positive genetic correlations in specialist and generalist insect herbivores expanding their diets to novel hosts

PubMed Central

GARCÍA-ROBLEDO, CARLOS; HORVITZ, CAROL C.

2011-01-01

One explanation for the widespread host specialization of insect herbivores is the “Jack of all trades-master of none” principle, which states that genotypes with high performance on one host will perform poorly on other hosts. This principle predicts that cross-host correlation in performance of genotypes will be negative. In this study we experimentally explored cross-host correlations and performance among families in four species (two generalist and two specialist) of leaf beetles (Cephaloleia spp.) that are currently expanding their diets from native to exotic plants. All four species displayed similar responses in body size, developmental rates and mortality rates to experimentally controlled diets. When raised on novel hosts, body size of larvae, pupae and adults were reduced. Development times were longer and larval mortality was higher on novel hosts. Genotype × host plant interactions were not detected for most traits. All significant cross-host correlations were positive. These results indicate very different ecological and evolutionary dynamics than those predicted by the “Jack of all trades-master of none” principle. PMID:22022877

Subpixelic measurement of large 1D displacements: principle, processing algorithms, performances and software.

PubMed

Guelpa, Valérian; Laurent, Guillaume J; Sandoz, Patrick; Zea, July Galeano; Clévy, Cédric

2014-03-12

This paper presents a visual measurement method able to sense 1D rigid body displacements with very high resolutions, large ranges and high processing rates. Sub-pixelic resolution is obtained thanks to a structured pattern placed on the target. The pattern is made of twin periodic grids with slightly different periods. The periodic frames are suited for Fourier-like phase calculations-leading to high resolution-while the period difference allows the removal of phase ambiguity and thus a high range-to-resolution ratio. The paper presents the measurement principle as well as the processing algorithms (source files are provided as supplementary materials). The theoretical and experimental performances are also discussed. The processing time is around 3 µs for a line of 780 pixels, which means that the measurement rate is mostly limited by the image acquisition frame rate. A 3-σ repeatability of 5 nm is experimentally demonstrated which has to be compared with the 168 µm measurement range.

Subpixelic Measurement of Large 1D Displacements: Principle, Processing Algorithms, Performances and Software

PubMed Central

Guelpa, Valérian; Laurent, Guillaume J.; Sandoz, Patrick; Zea, July Galeano; Clévy, Cédric

2014-01-01

This paper presents a visual measurement method able to sense 1D rigid body displacements with very high resolutions, large ranges and high processing rates. Sub-pixelic resolution is obtained thanks to a structured pattern placed on the target. The pattern is made of twin periodic grids with slightly different periods. The periodic frames are suited for Fourier-like phase calculations—leading to high resolution—while the period difference allows the removal of phase ambiguity and thus a high range-to-resolution ratio. The paper presents the measurement principle as well as the processing algorithms (source files are provided as supplementary materials). The theoretical and experimental performances are also discussed. The processing time is around 3 μs for a line of 780 pixels, which means that the measurement rate is mostly limited by the image acquisition frame rate. A 3-σ repeatability of 5 nm is experimentally demonstrated which has to be compared with the 168 μm measurement range. PMID:24625736

4 CFR 2.4 - Merit system principles.

Code of Federal Regulations, 2011 CFR

2011-01-01

... recognition should be provided for excellence in performance. (4) All employees should maintain high standards... education and training in cases in which such education and training would result in better organizational...

5 CFR 900.603 - Standards for a merit system of personnel administration.

Code of Federal Regulations, 2010 CFR

2010-01-01

... administration. 900.603 Section 900.603 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL... such merit principles as— (a) Recruiting, selecting, and advancing employees on the basis of their... high quality performance. (d) Retaining employees on the basis of the adequacy of their performance...

Assessing the Value of High School Accounting for the College Bound.

ERIC Educational Resources Information Center

Friedlob, George T.; Cosenza, Robert M.

1981-01-01

Reports results of a survey of first-quarter college accounting principles students. It was found that a typically difficult college course may be made easier and student performance improved by giving high school accounting instruction its proper importance in the curriculum of the business-oriented, college-bound high school student. (CT)

VLab: A Science Gateway for Distributed First Principles Calculations in Heterogeneous High Performance Computing Systems

ERIC Educational Resources Information Center

da Silveira, Pedro Rodrigo Castro

2014-01-01

This thesis describes the development and deployment of a cyberinfrastructure for distributed high-throughput computations of materials properties at high pressures and/or temperatures--the Virtual Laboratory for Earth and Planetary Materials--VLab. VLab was developed to leverage the aggregated computational power of grid systems to solve…

High Performance Liquid Chromatography Experiments to Undergraduate Laboratories

ERIC Educational Resources Information Center

Kissinger, Peter T.; And Others

1977-01-01

Reviews the principles of liquid chromatography with electrochemical detection (LCEC), an analytical technique that incorporates the advantages of both liquids chromatography and electrochemistry. Also suggests laboratory experiments using this technique. (MLH)

GPU acceleration of the Locally Selfconsistent Multiple Scattering code for first principles calculation of the ground state and statistical physics of materials

NASA Astrophysics Data System (ADS)

Eisenbach, Markus; Larkin, Jeff; Lutjens, Justin; Rennich, Steven; Rogers, James H.

2017-02-01

The Locally Self-consistent Multiple Scattering (LSMS) code solves the first principles Density Functional theory Kohn-Sham equation for a wide range of materials with a special focus on metals, alloys and metallic nano-structures. It has traditionally exhibited near perfect scalability on massively parallel high performance computer architectures. We present our efforts to exploit GPUs to accelerate the LSMS code to enable first principles calculations of O(100,000) atoms and statistical physics sampling of finite temperature properties. We reimplement the scattering matrix calculation for GPUs with a block matrix inversion algorithm that only uses accelerator memory. Using the Cray XK7 system Titan at the Oak Ridge Leadership Computing Facility we achieve a sustained performance of 14.5PFlop/s and a speedup of 8.6 compared to the CPU only code.

GPU acceleration of the Locally Selfconsistent Multiple Scattering code for first principles calculation of the ground state and statistical physics of materials

DOE PAGES

Eisenbach, Markus; Larkin, Jeff; Lutjens, Justin; ...

2016-07-12

The Locally Self-consistent Multiple Scattering (LSMS) code solves the first principles Density Functional theory Kohn–Sham equation for a wide range of materials with a special focus on metals, alloys and metallic nano-structures. It has traditionally exhibited near perfect scalability on massively parallel high performance computer architectures. In this paper, we present our efforts to exploit GPUs to accelerate the LSMS code to enable first principles calculations of O(100,000) atoms and statistical physics sampling of finite temperature properties. We reimplement the scattering matrix calculation for GPUs with a block matrix inversion algorithm that only uses accelerator memory. Finally, using the Craymore » XK7 system Titan at the Oak Ridge Leadership Computing Facility we achieve a sustained performance of 14.5PFlop/s and a speedup of 8.6 compared to the CPU only code.« less

Performance analysis of a microfluidic mixer based on high gradient magnetic separation principles

NASA Astrophysics Data System (ADS)

Liu, Mengyu; Han, Xiaotao; Cao, Quanliang; Li, Liang

2017-09-01

To achieve a rapid mixing between a water-based ferrofluid and DI water in a microfluidic environment, a magnetically actuated mixing system based on high gradient magnetic separation principles is proposed in this work. The microfluidic system consists of a T-shaped mirochannel and an array of integrated soft-magnetic elements at the sidewall of the channel. With the aid of an external magnetic bias field, these elements are magnetized to produce a magnetic volume force acting on the fluids containing magnetic nanoparticles, and then to induce additional flows for improving the mixing performance. The mixing process is numerically investigated through analyzing the concentration distribution of magnetic nanoparticles using a coupled particle-fluid transport model, and mixing performances under different parametrical conditions are investigated in detail. Numerical results show that a high mixing efficiency around 97.5% can be achieved within 2 s under an inlet flow rate of 1 mm s-1 and a relatively low magnetic bias field of 50 mT. Meanwhile, it has been found that there is an optimum number of magnetic elements used for obtaining the best mixing performance. These results show the potential of the proposed mixing method in lab-on-a-chip system and could be helpful in designing and optimizing system performance.

Making Employee Recognition a Tool for Achieving Improved Performance: Implication for Ghanaian Universities

ERIC Educational Resources Information Center

Amoatemaa, Abena Serwaa; Kyeremeh, Dorcas Darkoah

2016-01-01

Many organisations are increasingly making use of employee recognition to motivate employees to achieve high performance and productivity. Research has shown that effective recognition occurs in organisations that have strong supportive culture, understand the psychology of praising employees for their good work, and apply the principles of…

Lighting Studies for Fuelling Machine Deployed Visual Inspection Tool

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoots, Carl; Griffith, George

2015-04-01

Under subcontract to James Fisher Nuclear, Ltd., INL has been reviewing advanced vision systems for inspection of graphite in high radiation, high temperature, and high pressure environments. INL has performed calculations and proof-of-principle measurements of optics and lighting techniques to be considered for visual inspection of graphite fuel channels in AGR reactors in UK.

On Learning Natural-Science Categories That Violate the Family-Resemblance Principle.

PubMed

Nosofsky, Robert M; Sanders, Craig A; Gerdom, Alex; Douglas, Bruce J; McDaniel, Mark A

2017-01-01

The general view in psychological science is that natural categories obey a coherent, family-resemblance principle. In this investigation, we documented an example of an important exception to this principle: Results of a multidimensional-scaling study of igneous, metamorphic, and sedimentary rocks (Experiment 1) suggested that the structure of these categories is disorganized and dispersed. This finding motivated us to explore what might be the optimal procedures for teaching dispersed categories, a goal that is likely critical to science education in general. Subjects in Experiment 2 learned to classify pictures of rocks into compact or dispersed high-level categories. One group learned the categories through focused high-level training, whereas a second group was required to simultaneously learn classifications at a subtype level. Although high-level training led to enhanced performance when the categories were compact, subtype training was better when the categories were dispersed. We provide an interpretation of the results in terms of an exemplar-memory model of category learning.

Design rules of heteroatom-doped graphene to achieve high performance lithium-sulfur batteries: Both strong anchoring and catalysing based on first principles calculation.

PubMed

Zhang, Lin; Liang, Pei; Shu, Hai B; Man, Xiao L; Du, Xiao Q; Chao, Dong L; Liu, Zu G; Sun, Yu P; Wan, Hou Z; Wang, Hao

2018-06-18

A number of observations have been reported on chemical capture and catalysis of anchoring materials for lithium-sulfur batteries. Here, we propose the design principles for the chemical functioned graphene as an anchor material to realize both strong chemical trapping and catalysis. Through the first principle, the periodic law is calculated from the theory. Seven different co-doping series were investigated, e.g. MN 4 @graphene (M = V, Cr, Mn, Fe, Co, Ni, and Cu). From binding energy, partial density of state, and charge density difference analysis, the FeN 4 and CrN 4 co-doped graphene show good performance for the lithium-sulfur battery from both strong anchoring and catalytic effects. For the most kinds of Li 2 S x (x = 1, 2, 4, 6, 8) absorption, two combinations can be achieved, including S-bonding and Li-bonding. The competition between the MS and the NLi shows the main difference of the co-doped configurations. Moreover, the S-bonding systems have better performance for both moderate chemical trapping and strong catalysis. The binding energies of Li 2 S x and Li decomposed properties considered as the key descriptors for the rational design of lithium-sulfur battery. Lastly, we offer design rules for high performance lithium-sulfur batteries based on the chemical functional graphene materials. Copyright © 2018 Elsevier Inc. All rights reserved.

High Performance Object-Oriented Scientific Programming in Fortran 90

NASA Technical Reports Server (NTRS)

Norton, Charles D.; Decyk, Viktor K.; Szymanski, Boleslaw K.

1997-01-01

We illustrate how Fortran 90 supports object-oriented concepts by example of plasma particle computations on the IBM SP. Our experience shows that Fortran 90 and object-oriented methodology give high performance while providing a bridge from Fortran 77 legacy codes to modern programming principles. All of our object-oriented Fortran 90 codes execute more quickly thatn the equeivalent C++ versions, yet the abstraction modelling capabilities used for scentific programming are comparably powereful.

Massively parallel first-principles simulation of electron dynamics in materials

DOE PAGES

Draeger, Erik W.; Andrade, Xavier; Gunnels, John A.; ...

2017-08-01

Here we present a highly scalable, parallel implementation of first-principles electron dynamics coupled with molecular dynamics (MD). By using optimized kernels, network topology aware communication, and by fully distributing all terms in the time-dependent Kohn–Sham equation, we demonstrate unprecedented time to solution for disordered aluminum systems of 2000 atoms (22,000 electrons) and 5400 atoms (59,400 electrons), with wall clock time as low as 7.5 s per MD time step. Despite a significant amount of non-local communication required in every iteration, we achieved excellent strong scaling and sustained performance on the Sequoia Blue Gene/Q supercomputer at LLNL. We obtained up tomore » 59% of the theoretical sustained peak performance on 16,384 nodes and performance of 8.75 Petaflop/s (43% of theoretical peak) on the full 98,304 node machine (1,572,864 cores). Lastly, scalable explicit electron dynamics allows for the study of phenomena beyond the reach of standard first-principles MD, in particular, materials subject to strong or rapid perturbations, such as pulsed electromagnetic radiation, particle irradiation, or strong electric currents.« less

Massively parallel first-principles simulation of electron dynamics in materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Draeger, Erik W.; Andrade, Xavier; Gunnels, John A.

Here we present a highly scalable, parallel implementation of first-principles electron dynamics coupled with molecular dynamics (MD). By using optimized kernels, network topology aware communication, and by fully distributing all terms in the time-dependent Kohn–Sham equation, we demonstrate unprecedented time to solution for disordered aluminum systems of 2000 atoms (22,000 electrons) and 5400 atoms (59,400 electrons), with wall clock time as low as 7.5 s per MD time step. Despite a significant amount of non-local communication required in every iteration, we achieved excellent strong scaling and sustained performance on the Sequoia Blue Gene/Q supercomputer at LLNL. We obtained up tomore » 59% of the theoretical sustained peak performance on 16,384 nodes and performance of 8.75 Petaflop/s (43% of theoretical peak) on the full 98,304 node machine (1,572,864 cores). Lastly, scalable explicit electron dynamics allows for the study of phenomena beyond the reach of standard first-principles MD, in particular, materials subject to strong or rapid perturbations, such as pulsed electromagnetic radiation, particle irradiation, or strong electric currents.« less

Student error patterns as a function of curriculum design: teaching fractions to remedial high school students and high school students with learning disabilities.

PubMed

Kelly, B; Gersten, R; Carnine, D

1990-01-01

This study evaluated the relative effectiveness of a curriculum that incorporated three empirically derived principles of curriculum design with a basal approach in teaching basic fractions concepts to students with learning disabilities and other low performing students in high school remedial math classes. The components of effective mathematics instruction articulated by Good and Grouws (1979) were implemented in both conditions. Thus, the curriculum design variables were isolated by keeping all other aspects of instruction constant. Results indicated that, although both programs were reasonably successful in teaching the material, the curriculum program utilizing sophisticated principles of curriculum design was significantly more effective. Mean scores on a curriculum-referenced test were 96.5% for that group and 82.3% for the basal group. Secondary analyses of item clusters revealed that areas of weakness in the performance of the basal group could be directly linked to hypothesized flaws in its curriculum design.

Identification of lymphogranuloma venereum-associated Chlamydia trachomatis serovars by fluorescence in situ hybridisation--a proof-of-principle analysis.

PubMed

Frickmann, Hagen; Essig, Andreas; Poppert, Sven

2014-04-01

We describe a proof-of-principle evaluation of a fluorescence in situ hybridisation (FISH) procedure to identify Chlamydia trachomatis serovars L1-L3, the causative agents of lymphogranuloma venereum, in cell cultures based on newly designed DNA probes. Rapid and easy-to-perform FISH could facilitate the diagnosis of lymphogranuloma venereum without nucleic acid amplification or serotyping, but requires broader evaluation studies, for example, in tropical high-endemicity regions. © 2014 John Wiley & Sons Ltd.

Computational fluid mechanics utilizing the variational principle of modeling damping seals

NASA Technical Reports Server (NTRS)

Abernathy, J. M.

1986-01-01

A computational fluid dynamics code for application to traditional incompressible flow problems has been developed. The method is actually a slight compressibility approach which takes advantage of the bulk modulus and finite sound speed of all real fluids. The finite element numerical analog uses a dynamic differencing scheme based, in part, on a variational principle for computational fluid dynamics. The code was developed in order to study the feasibility of damping seals for high speed turbomachinery. Preliminary seal analyses have been performed.

Fulfillment of Similarity Principles for Pulsed Discharges in a Highly Inhomogeneous Field at High Pressures Under Conditions of Runaway Electron Generation

NASA Astrophysics Data System (ADS)

Baksht, E. Kh.; Buranchenko, A. G.; Kozyrev, A. V.; Tarasenko, V. F.

2017-12-01

An analysis of the fulfillment of the similarity law pτ = f(E/p) under conditions of a pulsed discharge triggered in a gas diode with a highly inhomogeneous field at the voltage in the incident wave >100 kV is performed. It is shown that in this case within the pressure range 1-12 atm the deviations from the similarity principles E/p(pτ) and Ubr(pd) are due to the nonconservation of proportions in the gas-filled diode geometry. Using a collector, the beam of runaway electrons is for the first time registered behind the anode foil in nitrogen at the pressure from 5 to 12 atm.

Principles for Health System Capacity Planning: Insights for Healthcare Leaders.

PubMed

Shaw, James; Wong, Ivy; Griffin, Bailey; Robertson, Michael; Bhatia, R Sacha

2017-01-01

Jurisdictions across Canada and around the world face the challenge of planning high-performing and sustainable health systems in response to growing healthcare demands. In this paper, we report on the process of developing principles for health system capacity planning by the Ministry of Health and Long-Term Care in Ontario. Integrating the results of a literature review on health system planning and a symposium with representatives from local health integration networks, we describe the following six principles in detail: (1) develop an aspirational vision, (2) establish clear leadership, (3) commit to stakeholder engagement, (4) engage patients and the public, (5) build analytics infrastructure and (6) revise policy when necessary.

Design considerations for a space-borne ocean surface laser altimeter

NASA Technical Reports Server (NTRS)

Plotkin, H. H.

1972-01-01

Design procedures for using laser ranging systems in spacecraft to reflect ocean surface pulses vertically and measure spacecraft altitude with high precision are examined. Operating principles and performance experience of a prototype system are given.

Development of a model to assess environmental performance, concerning HSE-MS principles.

PubMed

Abbaspour, M; Hosseinzadeh Lotfi, F; Karbassi, A R; Roayaei, E; Nikoomaram, H

2010-06-01

The main objective of the present study was to develop a valid and appropriate model to evaluate companies' efficiency and environmental performance, concerning health, safety, and environmental management system principles. The proposed model overcomes the shortcomings of the previous models developed in this area. This model has been designed on the basis of a mathematical method known as Data Envelopment Analysis (DEA). In order to differentiate high-performing companies from weak ones, one of DEA nonradial models named as enhanced Russell graph efficiency measure has been applied. Since some of the environmental performance indicators cannot be controlled by companies' managers, it was necessary to develop the model in a way that it could be applied when discretionary and/or nondiscretionary factors were involved. The model, then, has been modified on a real case that comprised 12 oil and gas general contractors. The results showed the relative efficiency, inefficiency sources, and the rank of contractors.

A Scanning scheimpflug lidar system developed for urban pollution monitoring

NASA Astrophysics Data System (ADS)

Yang, Yang; Guan, Peng; Mei, Liang

2018-04-01

A scanning Scheimpflug lidar system based on the Scheimpflug principle has been developed by employing a high power multimode 808 nm laser diode and a highly integrated CMOS sensor in Dalian University of Technology, Dalian, Northern China. Atmospheric scanning measurements in urban area were performed for the studies of particle emission sources.

Developments in variational methods for high performance plate and shell elements

NASA Technical Reports Server (NTRS)

Felippa, Carlos A.; Militello, Carmelo

1991-01-01

High performance elements are simple finite elements constructed to deliver engineering accuracy with coarse arbitrary grids. This is part of a series on the variational foundations of high-performance elements, with emphasis on plate and shell elements constructed with the free formulation (FF) and assumed natural strain (ANS) methods. Parameterized variational principles are studied that provide a common foundation for the FF and ANS methods, as well as for a combination of both. From this unified formulation a variant of the ANS formulation, called the assumed natural deviatoric strain (ANDES) formulation, emerges as an important special case. The first ANDES element, a high-performance 9 degrees of freedom triangular Kirchhoff plate bending element, is briefly described to illustrate the use of the new formulation.

First Principles Modeling of the Performance of a Hydrogen-Peroxide-Driven Chem-E-Car

ERIC Educational Resources Information Center

Farhadi, Maryam; Azadi, Pooya; Zarinpanjeh, Nima

2009-01-01

In this study, performance of a hydrogen-peroxide-driven car has been simulated using basic conservation laws and a few numbers of auxiliary equations. A numerical method was implemented to solve sets of highly non-linear ordinary differential equations. Transient pressure and the corresponding traveled distance for three different car weights are…

Principles of Design for High Performing Organizations: An Assessment of the State of the Field of Organizational Design Research

DTIC Science & Technology

1994-03-01

asked whether the planned structure considered (a) all objectives, (b) all functions, (c) all relevant units of analysis such as the plant , the...literature and provides an integrative model of design for high perfor-ming organizations. The model is based on an analysis of current theories of...important midrange theories underlie much of the work on organizational analysis . 0 Systems Approaches. These approaches emphasize the rational, goal

High capacity demonstration of honeycomb panel heat pipes

NASA Technical Reports Server (NTRS)

Tanzer, H. J.

1989-01-01

The feasibility of performance enhancing the sandwich panel heat pipe was investigated for moderate temperature range heat rejection radiators on future-high-power spacecraft. The hardware development program consisted of performance prediction modeling, fabrication, ground test, and data correlation. Using available sandwich panel materials, a series of subscale test panels were augumented with high-capacity sideflow and temperature control variable conductance features, and test evaluated for correlation with performance prediction codes. Using the correlated prediction model, a 50-kW full size radiator was defined using methanol working fluid and closely spaced sideflows. A new concept called the hybrid radiator individually optimizes heat pipe components. A 2.44-m long hybrid test vehicle demonstrated proof-of-principle performance.

The effects of timing of exposure to principles and procedural instruction specificity on learning an electrical troubleshooting skill.

PubMed

Eiriksdottir, Elsa; Catrambone, Richard

2015-12-01

Domain principles provided in task instructions are assumed to help performance as learners can later apply this knowledge when faced with new tasks. The goal of the research was to investigate whether the timing of the exposure to principles-studying the principles before or while completing training tasks-and the specificity in the accompanying step-by-step procedural instructions would influence learning to troubleshoot a simulated electrical circuit. The results of a pilot study suggested that timing of principle exposure and specificity might interact. This was investigated by comparing the performance of 4 groups of participants (n = 24) who received either general or detailed procedural instructions and were either exposed to the principles before or during the training. The results showed that studying the principles before training benefited test task performance when the procedural instructions were detailed but not when they were general. The results also showed that using general procedural instructions benefited test task performance while using detailed procedural instructions benefited training task performance. Overall the results reveal how the learning situation as a whole must be considered when determining the efficacy of instructional materials, and how conditions can be created where principles enhance learning. (c) 2015 APA, all rights reserved).

Design, Development and Application of New, High-Performance Gear Steels

DTIC Science & Technology

2010-02-01

thesis work focused on design principles for advanced carburized bearing steels . He also received a Master of Product Development degree from...Design computational design technology to develop a new class of high-strength, secondary hardening gear steels that are optimized for high-temperature...high contact fatigue resistance, which makes it a candidate for applications such as camshafts and bearings , as well as gear sets. (Printed with

Pressure-induced structural phase transformation and superconducting properties of titanium mononitride

NASA Astrophysics Data System (ADS)

Li, Qian; Guo, Yanan; Zhang, Miao; Ge, Xinlei

2018-03-01

In this work, we have systematically performed the first-principles structure search on titanium mononitride (TiN) within Crystal Structure AnaLYsis by Particle Swarm Optimization (CALYPSO) methodology at high pressures. Here, we have confirmed a phase transition from cubic rock-salt (fcc) phase to CsCl (bcc) phase of TiN at ∼348 GPa. Further simulations reveal that the bcc phase is dynamically stable, and could be synthesized experimentally in principle. The calculated elastic anisotropy decreases with the phase transformation from fcc to bcc structure under high pressures, and the material changes from ductile to brittle simultaneously. Moreover, we found that both structures are superconductive with the superconducting critical temperature of 2-12 K.

Coding conventions and principles for a National Land-Change Modeling Framework

USGS Publications Warehouse

Donato, David I.

2017-07-14

This report establishes specific rules for writing computer source code for use with the National Land-Change Modeling Framework (NLCMF). These specific rules consist of conventions and principles for writing code primarily in the C and C++ programming languages. Collectively, these coding conventions and coding principles create an NLCMF programming style. In addition to detailed naming conventions, this report provides general coding conventions and principles intended to facilitate the development of high-performance software implemented with code that is extensible, flexible, and interoperable. Conventions for developing modular code are explained in general terms and also enabled and demonstrated through the appended templates for C++ base source-code and header files. The NLCMF limited-extern approach to module structure, code inclusion, and cross-module access to data is both explained in the text and then illustrated through the module templates. Advice on the use of global variables is provided.

Task-specific reorganization of the auditory cortex in deaf humans

PubMed Central

Bola, Łukasz; Zimmermann, Maria; Mostowski, Piotr; Jednoróg, Katarzyna; Marchewka, Artur; Rutkowski, Paweł; Szwed, Marcin

2017-01-01

The principles that guide large-scale cortical reorganization remain unclear. In the blind, several visual regions preserve their task specificity; ventral visual areas, for example, become engaged in auditory and tactile object-recognition tasks. It remains open whether task-specific reorganization is unique to the visual cortex or, alternatively, whether this kind of plasticity is a general principle applying to other cortical areas. Auditory areas can become recruited for visual and tactile input in the deaf. Although nonhuman data suggest that this reorganization might be task specific, human evidence has been lacking. Here we enrolled 15 deaf and 15 hearing adults into an functional MRI experiment during which they discriminated between temporally complex sequences of stimuli (rhythms). Both deaf and hearing subjects performed the task visually, in the central visual field. In addition, hearing subjects performed the same task in the auditory modality. We found that the visual task robustly activated the auditory cortex in deaf subjects, peaking in the posterior–lateral part of high-level auditory areas. This activation pattern was strikingly similar to the pattern found in hearing subjects performing the auditory version of the task. Although performing the visual task in deaf subjects induced an increase in functional connectivity between the auditory cortex and the dorsal visual cortex, no such effect was found in hearing subjects. We conclude that in deaf humans the high-level auditory cortex switches its input modality from sound to vision but preserves its task-specific activation pattern independent of input modality. Task-specific reorganization thus might be a general principle that guides cortical plasticity in the brain. PMID:28069964

Task-specific reorganization of the auditory cortex in deaf humans.

PubMed

Bola, Łukasz; Zimmermann, Maria; Mostowski, Piotr; Jednoróg, Katarzyna; Marchewka, Artur; Rutkowski, Paweł; Szwed, Marcin

2017-01-24

The principles that guide large-scale cortical reorganization remain unclear. In the blind, several visual regions preserve their task specificity; ventral visual areas, for example, become engaged in auditory and tactile object-recognition tasks. It remains open whether task-specific reorganization is unique to the visual cortex or, alternatively, whether this kind of plasticity is a general principle applying to other cortical areas. Auditory areas can become recruited for visual and tactile input in the deaf. Although nonhuman data suggest that this reorganization might be task specific, human evidence has been lacking. Here we enrolled 15 deaf and 15 hearing adults into an functional MRI experiment during which they discriminated between temporally complex sequences of stimuli (rhythms). Both deaf and hearing subjects performed the task visually, in the central visual field. In addition, hearing subjects performed the same task in the auditory modality. We found that the visual task robustly activated the auditory cortex in deaf subjects, peaking in the posterior-lateral part of high-level auditory areas. This activation pattern was strikingly similar to the pattern found in hearing subjects performing the auditory version of the task. Although performing the visual task in deaf subjects induced an increase in functional connectivity between the auditory cortex and the dorsal visual cortex, no such effect was found in hearing subjects. We conclude that in deaf humans the high-level auditory cortex switches its input modality from sound to vision but preserves its task-specific activation pattern independent of input modality. Task-specific reorganization thus might be a general principle that guides cortical plasticity in the brain.

Promising thermoelectric properties of phosphorenes.

PubMed

Sevik, Cem; Sevinçli, Hâldun

2016-09-02

Electronic, phononic, and thermoelectric transport properties of single layer black- and blue-phosphorene structures are investigated with first-principles based ballistic electron and phonon transport calculations employing hybrid functionals. The maximum values of room temperature thermoelectric figure of merit, ZT corresponding to armchair and zigzag directions of black-phosphorene, ∼0.5 and ∼0.25, are calculated as rather smaller than those obtained with first-principles based semiclassical Boltzmann transport theory calculations. On the other hand, the maximum value of room temperature ZT of blue-phosphorene is predicted to be substantially high and remarkable values as high as 2.5 are obtained for elevated temperatures. Besides the fact that these figures are obtained at the ballistic limit, our findings mark the strong possibility of high thermoelectric performance of blue-phosphorene in new generation thermoelectric applications.

Effects of the High School Economics Curriculum on Learning in the College Principles Class.

ERIC Educational Resources Information Center

Lopus, Jane S.

1997-01-01

Asserts that most research into the effects of high school economics curriculum upon performance in college level economics courses fails to consider that secondary economics education rarely teaches micro- and macroeconomic concepts. Discovers that any gap in learning between students in economics is narrowed by the first semester in college.…

Controlled-Root Approach To Digital Phase-Locked Loops

NASA Technical Reports Server (NTRS)

Stephens, Scott A.; Thomas, J. Brooks

1995-01-01

Performance tailored more flexibly and directly to satisfy design requirements. Controlled-root approach improved method for analysis and design of digital phase-locked loops (DPLLs). Developed rigorously from first principles for fully digital loops, making DPLL theory and design simpler and more straightforward (particularly for third- or fourth-order DPLL) and controlling performance more accurately in case of high gain.

Does the Relative Strength of Grouping Principles Modulate the Interactions between them?

PubMed

Montoro, Pedro R; Luna, Dolores

2015-06-05

This study examines the influence of the relative strength of grouping principles on interactions between the intrinsic principle of proximity and the extrinsic principle of common region in the process of perceptual organization. Cooperation and competition between intrinsic and extrinsic principles were examined by presenting the principle either alone or conjoined with another principle. The relative grouping strength of the principles operating alone was varied in two different groups of participants so that it was similar for one group and very different for the other group. Results showed that, when principles acting alone had different strengths, the grouping effect of the strongest principle was similar to that of the cooperation condition, and the effect of the weakest principle was similar to that of competing conjoined principles. In contrast, when the strength of principles acting alone was similar, the effect of conjoined cooperating principles was greater than that of either principle acting alone. Moreover, the effect of conjoined competing principles was smaller than that of either principle operating alone. Results show that cooperation and competition between intrinsic and extrinsic principles are modulated by the relative grouping strength of principles acting alone. Furthermore, performance in these conditions could be predicted on the basis of performance in single-principle conditions.

The three keys to quality customer service: opening the doors to exceptional performance.

PubMed

Myers, Pennie; Nance, Don W

2002-01-01

Excellence in customer service requires three things. The first is a commitment to a set of principles. These principles reflect beliefs and assumptions that people are valuable and deserve to be treated with dignity and respect. This commitment is expressed to customers by an adherence to six customer-friendly processes and by personnel who possess a high level of skill in the behaviors that make up customer service. When these three requirements are met, laboratorians not only maintain a competitive edge but also fulfill their mission as health-care professionals.

Proportional-scanning-phase method to suppress the vibrational noise in nonisotope dual-atom-interferometer-based weak-equivalence-principle-test experiments

NASA Astrophysics Data System (ADS)

Chen, Xi; Zhong, Jiaqi; Song, Hongwei; Zhu, Lei; Wang, Jin; Zhan, Mingsheng

2014-08-01

Vibrational noise is one of the most important noises that limits the performance of the nonisotopes atom-interferometers (AIs) -based weak-equivalence-principle (WEP) -test experiment. By analyzing the vibration-induced phases, we find that, although the induced phases are not completely common, their ratio is always a constant at every experimental data point, which is not fully utilized in the traditional elliptic curve-fitting method. From this point, we propose a strategy that can greatly suppress the vibration-induced phase noise by stabilizing the Raman laser frequencies at high precision and controlling the scanning-phase ratio. The noise rejection ratio can be as high as 1015 with arbitrary dual-species AIs. Our method provides a Lissajous curve, and the shape of the curve indicates the breakdown of the weak-equivalence-principle signal. Then we manage to derive an estimator for the differential phase of the Lissajous curve. This strategy could be helpful in extending the candidates of atomic species for high-precision AIs-based WEP-test experiments.

The highly intelligent virtual agents for modeling financial markets

NASA Astrophysics Data System (ADS)

Yang, G.; Chen, Y.; Huang, J. P.

2016-02-01

Researchers have borrowed many theories from statistical physics, like ensemble, Ising model, etc., to study complex adaptive systems through agent-based modeling. However, one fundamental difference between entities (such as spins) in physics and micro-units in complex adaptive systems is that the latter are usually with high intelligence, such as investors in financial markets. Although highly intelligent virtual agents are essential for agent-based modeling to play a full role in the study of complex adaptive systems, how to create such agents is still an open question. Hence, we propose three principles for designing high artificial intelligence in financial markets and then build a specific class of agents called iAgents based on these three principles. Finally, we evaluate the intelligence of iAgents through virtual index trading in two different stock markets. For comparison, we also include three other types of agents in this contest, namely, random traders, agents from the wealth game (modified on the famous minority game), and agents from an upgraded wealth game. As a result, iAgents perform the best, which gives a well support for the three principles. This work offers a general framework for the further development of agent-based modeling for various kinds of complex adaptive systems.

Signal noise ratio analysis and on-orbit performance estimation of a solar occultation Fourier transform spectrometer

NASA Astrophysics Data System (ADS)

Li, Bicen; Xu, Pengmei; Hou, Lizhou; Wang, Caiqin

2017-10-01

Taking the advantages of high spectral resolution, high sensitivity and wide spectral coverage, space borne Fourier transform infrared spectrometer (FTS) plays more and more important role in atmospheric composition sounding. The combination of solar occultation and FTS technique improves the sensitivity of instrument. To achieve both high spectral resolution and high signal to noise ratio (SNR), reasonable allocation and optimization for instrument parameters are the foundation and difficulty. The solar occultation FTS (SOFTS) is a high spectral resolution (0.03 cm-1) FTS operating from 2.4 to 13.3 μm (750-4100cm-1), which will determine the altitude profile information of typical 10-100km for temperature, pressure, and the volume mixing ratios for several dozens of atmospheric compositions. As key performance of SOFTS, SNR is crucially important to high accuracy retrieval of atmospheric composition, which is required to be no less than 100:1 at the radiance of 5800K blackbody. Based on the study of various parameters and its interacting principle, according to interference theory and operation principle of time modulated FTS, a simulation model of FTS SNR has been built, which considers satellite orbit, spectral radiometric features of sun and atmospheric composition, optical system, interferometer and its control system, measurement duration, detector sensitivity, noise of detector and electronic system and so on. According to the testing results of SNR at the illuminating of 1000 blackbody, the on-orbit SNR performance of SOFTS is estimated, which can meet the mission requirement.

Separation and sorting of cells in microsystems using physical principles

NASA Astrophysics Data System (ADS)

Lee, Gi-Hun; Kim, Sung-Hwan; Ahn, Kihoon; Lee, Sang-Hoon; Park, Joong Yull

2016-01-01

In the last decade, microfabrication techniques have been combined with microfluidics and applied to cell biology. Utilizing such new techniques, various cell studies have been performed for the research of stem cells, immune cells, cancer, neurons, etc. Among the various biological applications of microtechnology-based platforms, cell separation technology has been highly regarded in biological and clinical fields for sorting different types of cells, finding circulating tumor cells (CTCs), and blood cell separation, amongst other things. Many cell separation methods have been created using various physical principles. Representatively, these include hydrodynamic, acoustic, dielectrophoretic, magnetic, optical, and filtering methods. In this review, each of these methods will be introduced, and their physical principles and sample applications described. Each physical principle has its own advantages and disadvantages. The engineers who design the systems and the biologists who use them should understand the pros and cons of each method or principle, to broaden the use of microsystems for cell separation. Continuous development of microsystems for cell separation will lead to new opportunities for diagnosing CTCs and cancer metastasis, as well as other elements in the bloodstream.

Matching Judicial Supervision to Clients’ Risk Status in Drug Court

PubMed Central

Marlowe, Douglas B.; Festinger, David S.; Lee, Patricia A.; Dugosh, Karen L.; Benasutti, Kathleen M.

2007-01-01

This article reports outcomes from a program of experimental research evaluating the risk principle in drug courts. Prior studies revealed that participants who were high risk and had (a) antisocial personality disorder or (b) a prior history of drug abuse treatment performed better in drug court when scheduled to attend biweekly judicial status hearings in court. In contrast, participants who were low risk performed equivalently regardless of the court hearings schedule. This study prospectively matches drug court clients to the optimal schedule of court hearings based on an assessment of their risk status and compares outcomes to clients randomly assigned to the standard hearings schedule. Results confirmed that participants who were high risk and matched to biweekly hearings had better during-treatment outcomes than participants assigned to status hearings as usual. These findings provide confirmation of the risk principle in drug courts and yield practical information for enhancing the efficacy and cost-efficiency of drug courts. PMID:18174915

Practices in Adequate Structural Design

NASA Technical Reports Server (NTRS)

Ryan, Robert S.

1989-01-01

Structural design and verification of space vehicles and space systems is a very tricky and awe inspiring business, particularly for manned missions. Failures in the missions with loss of life is devastating personally and nationally. The scope of the problem is driven by high performance requirements which push state-of-the-art technologies, creating high sensitivites to small variations and uncertainties. Insurance of safe, reliable flight dictates the use of sound principles, procedures, analysis, and testing. Many of those principles which were refocused by the Space Shuttle Challenger (51-L) accident on January 26, 1986, and the activities conducted to insure safe shuttle reflights are discussed. The emphasis will be focused on engineering, while recognizing that project and project management are also key to success.

Practices in adequate structural design

NASA Astrophysics Data System (ADS)

Ryan, Robert S.

1989-01-01

Structural design and verification of space vehicles and space systems is a very tricky and awe inspiring business, particularly for manned missions. Failures in the missions with loss of life is devastating personally and nationally. The scope of the problem is driven by high performance requirements which push state-of-the-art technologies, creating high sensitivites to small variations and uncertainties. Insurance of safe, reliable flight dictates the use of sound principles, procedures, analysis, and testing. Many of those principles which were refocused by the Space Shuttle Challenger (51-L) accident on January 26, 1986, and the activities conducted to insure safe shuttle reflights are discussed. The emphasis will be focused on engineering, while recognizing that project and project management are also key to success.

Mechanical Design of Downhole Tractor Based on Two-Way Self-locking Mechanism

NASA Astrophysics Data System (ADS)

Fang, Delei; Shang, Jianzhong; Luo, Zirong; Wu, Guoheng; Liu, Yiying

2018-03-01

Based on the technology of horizontal well tractor, a kind of downhole tractor was developed which can realize Two-Way self-locking function. Aiming at the needs of horizontal well logging to realize the target of small size, high traction and high reliability, the tractor selects unique heart-shaped CAM as the locking mechanism. The motion principle of telescopic downhole tractor, the design of mechanical structure and locking principle of the locking mechanism are all analyzed. The mathematical expressions of traction are obtained by mechanical analysis of parallel support rod in the locking mechanism. The force analysis and contour design of the heart-shaped CAM are performed, which can lay the foundation for the development of tractor prototype.

Scientific Data Services -- A High-Performance I/O System with Array Semantics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Kesheng; Byna, Surendra; Rotem, Doron

2011-09-21

As high-performance computing approaches exascale, the existing I/O system design is having trouble keeping pace in both performance and scalability. We propose to address this challenge by adopting database principles and techniques in parallel I/O systems. First, we propose to adopt an array data model because many scientific applications represent their data in arrays. This strategy follows a cardinal principle from database research, which separates the logical view from the physical layout of data. This high-level data model gives the underlying implementation more freedom to optimize the physical layout and to choose the most effective way of accessing the data.more » For example, knowing that a set of write operations is working on a single multi-dimensional array makes it possible to keep the subarrays in a log structure during the write operations and reassemble them later into another physical layout as resources permit. While maintaining the high-level view, the storage system could compress the user data to reduce the physical storage requirement, collocate data records that are frequently used together, or replicate data to increase availability and fault-tolerance. Additionally, the system could generate secondary data structures such as database indexes and summary statistics. We expect the proposed Scientific Data Services approach to create a “live” storage system that dynamically adjusts to user demands and evolves with the massively parallel storage hardware.« less

Procedural instructions, principles, and examples: how to structure instructions for procedural tasks to enhance performance, learning, and transfer.

PubMed

Eiriksdottir, Elsa; Catrambone, Richard

2011-12-01

The goal of this article is to investigate how instructions can be constructed to enhance performance and learning of procedural tasks. Important determinants of the effectiveness of instructions are type of instructions (procedural information, principles, and examples) and pedagogical goal (initial performance, learning, and transfer). Procedural instructions describe how to complete tasks in a stepwise manner, principles describe rules governing the tasks, and examples demonstrate how instances of the task are carried out. The authors review the research literature associated with each type of instruction to identify factors determining effectiveness for different pedagogical goals. The results suggest a trade-off between usability and learnability. Specific instructions help initial performance, whereas more general instructions, requiring problem solving, help learning and transfer. Learning from instructions takes cognitive effort, and research suggests that learners typically opt for low effort. However, it is possible to meet both goals of good initial performance and learning with methods such as fading and by combining different types of instructions. How instructions are constructed influences their effectiveness for the goals of good initial performance, learning, and transfer, and it is therefore important for researchers and practitioners alike to define the pedagogical goal of instructions. If the goal is good initial performance, then instructions should highly resemble the task at hand (e.g., in the form of detailed procedural instructions and examples), but if the goal is good learning and transfer, then instructions should be more abstract, inducing learners to expend the necessary cognitive effort for learning.

Molecular Design of Performance Proteins With Repetitive Sequences

NASA Astrophysics Data System (ADS)

Vendrely, Charlotte; Ackerschott, Christian; Römer, Lin; Scheibel, Thomas

Most performance proteins responsible for the mechanical stability of cells and organisms reveal highly repetitive sequences. Mimicking such performance proteins is of high interest for the design of nanostructured biomaterials. In this article, flagelliform silk is exemplary introduced to describe a general principle for designing genes of repetitive performance proteins for recombinant expression in Escherichia coli . In the first step, repeating amino acid sequence motifs are reversely transcripted into DNA cassettes, which can in a second step be seamlessly ligated, yielding a designed gene. Recombinant expression thereof leads to proteins mimicking the natural ones. The recombinant proteins can be assembled into nanostructured materials in a controlled manner, allowing their use in several applications.

New bimetallic EMF cell shows promise in direct energy conversion

NASA Technical Reports Server (NTRS)

Hesson, J. C.; Shimotake, H.

1968-01-01

Concentration cell, based upon a thermally regenerative cell principle, produces electrical energy from any large heat source. This experimental bimetallic EMF cell uses a sodium-bismuth alloy cathode and a pure liquid sodium anode. The cell exhibits reliability, corrosion resistance, and high current density performance.

In Praise of Monetary Motivation.

ERIC Educational Resources Information Center

Piamonte, John S.

1979-01-01

Although management has built remuneration policies on the belief that money does not motivate personnel, the author states that the best way to encourage high performance is still money if administered correctly. He discusses behavior theories, incentive/contingency principles, the weaknesses of many merit pay schemes, and factors in employee…

Analysis of Tactical, Decisional and Executional Behaviour according to the Level of Expertise in Squash

PubMed Central

Catalán-Eslava, María; González-Víllora, Sixto; Pastor-Vicedo, Juan C.; Contreras-Jordán, Onofre R.

2018-01-01

Abstract The objective of this study was to analyse the differences in tactical principles, decision-making and execution of the return shot and drop shot of squash players at different levels of proficiency. The sample was composed of 80 players, divided into four levels of expertise (first national category, second national category, autonomous regional level and provincial level). The Squash Performance Evaluation Tool was used for recording the level of decision-making and execution. The results revealed that reading of the context of the game improved as the level of the player’s expertise of both the return shot and the drop shot increased. The correlation between correct decision-making and better quality execution for both the return shot and the drop shot in squash also improved with the player’s level of expertise. According to these results, improvements in situational tactical principles and the application of tactical principles, correct decision-making and high-quality execution are essential to develop the athletic performance level among squash players. PMID:29599875

Beyond Moore’s technologies: operation principles of a superconductor alternative

PubMed Central

Klenov, Nikolay V; Bakurskiy, Sergey V; Kupriyanov, Mikhail Yu; Gudkov, Alexander L; Sidorenko, Anatoli S

2017-01-01

The predictions of Moore’s law are considered by experts to be valid until 2020 giving rise to “post-Moore’s” technologies afterwards. Energy efficiency is one of the major challenges in high-performance computing that should be answered. Superconductor digital technology is a promising post-Moore’s alternative for the development of supercomputers. In this paper, we consider operation principles of an energy-efficient superconductor logic and memory circuits with a short retrospective review of their evolution. We analyze their shortcomings in respect to computer circuits design. Possible ways of further research are outlined. PMID:29354341

First-principles Electronic Structure Calculations for Scintillation Phosphor Nuclear Detector Materials

NASA Astrophysics Data System (ADS)

Canning, Andrew

2013-03-01

Inorganic scintillation phosphors (scintillators) are extensively employed as radiation detector materials in many fields of applied and fundamental research such as medical imaging, high energy physics, astrophysics, oil exploration and nuclear materials detection for homeland security and other applications. The ideal scintillator for gamma ray detection must have exceptional performance in terms of stopping power, luminosity, proportionality, speed, and cost. Recently, trivalent lanthanide dopants such as Ce and Eu have received greater attention for fast and bright scintillators as the optical 5d to 4f transition is relatively fast. However, crystal growth and production costs remain challenging for these new materials so there is still a need for new higher performing scintillators that meet the needs of the different application areas. First principles calculations can provide a useful insight into the chemical and electronic properties of such materials and hence can aid in the search for better new scintillators. In the past there has been little first-principles work done on scintillator materials in part because it means modeling f electrons in lanthanides as well as complex excited state and scattering processes. In this talk I will give an overview of the scintillation process and show how first-principles calculations can be applied to such systems to gain a better understanding of the physics involved. I will also present work on a high-throughput first principles approach to select new scintillator materials for fabrication as well as present more detailed calculations to study trapping process etc. that can limit their brightness. This work in collaboration with experimental groups has lead to the discovery of some new bright scintillators. Work supported by the U.S. Department of Homeland Security and carried out under U.S. Department of Energy Contract no. DE-AC02-05CH11231 at Lawrence Berkeley National Laboratory.

Research on Shore-Ship Photonic Link Performance for Two- Frequency-Band Signals

NASA Astrophysics Data System (ADS)

Zuo, Yanqin; Cong, Bo

2016-02-01

Ka and Ku bands links for shore-ship communications suffer limited bandwidth and high loss. In this paper, photonics-based links are proposed and modeled. The principle of phase modulation (PM) is elaborated and analyzed. It is showed that PM can effectively suppress high-order inter-modulation distortion (IMD), reduce the insert loss and improve the reliability of the system.

High Performance Computing Modeling Advances Accelerator Science for High-Energy Physics

DOE PAGES

Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

2014-07-28

The development and optimization of particle accelerators are essential for advancing our understanding of the properties of matter, energy, space, and time. Particle accelerators are complex devices whose behavior involves many physical effects on multiple scales. Therefore, advanced computational tools utilizing high-performance computing are essential for accurately modeling them. In the past decade, the US Department of Energy's SciDAC program has produced accelerator-modeling tools that have been employed to tackle some of the most difficult accelerator science problems. The authors discuss the Synergia framework and its applications to high-intensity particle accelerator physics. Synergia is an accelerator simulation package capable ofmore » handling the entire spectrum of beam dynamics simulations. Our authors present Synergia's design principles and its performance on HPC platforms.« less

A novel simultaneous streak and framing camera without principle errors

NASA Astrophysics Data System (ADS)

Jingzhen, L.; Fengshan, S.; Ningwen, L.; Xiangdong, G.; Bin, H.; Qingyang, W.; Hongyi, C.; Yi, C.; Xiaowei, L.

2018-02-01

A novel simultaneous streak and framing camera with continuous access, the perfect information of which is far more important for the exact interpretation and precise evaluation of many detonation events and shockwave phenomena, has been developed. The camera with the maximum imaging frequency of 2 × 106 fps and the maximum scanning velocity of 16.3 mm/μs has fine imaging properties which are the eigen resolution of over 40 lp/mm in the temporal direction and over 60 lp/mm in the spatial direction and the framing frequency principle error of zero for framing record, and the maximum time resolving power of 8 ns and the scanning velocity nonuniformity of 0.136%~-0.277% for streak record. The test data have verified the performance of the camera quantitatively. This camera, simultaneously gained frames and streak with parallax-free and identical time base, is characterized by the plane optical system at oblique incidence different from space system, the innovative camera obscura without principle errors, and the high velocity motor driven beryllium-like rotating mirror, made of high strength aluminum alloy with cellular lateral structure. Experiments demonstrate that the camera is very useful and reliable to take high quality pictures of the detonation events.

Fundamental Tactical Principles of Soccer: A Comparison of Different Age Groups

PubMed Central

Guilherme, José; Rechenchosky, Leandro; da Costa, Luciane Cristina Arantes; Rinadi, Wilson

2017-01-01

Abstract The fundamental tactical principles of the game of soccer represent a set of action rules that guide behaviours related to the management of game space. The aim of this study was to compare the performance of fundamental offensive and defensive tactical principles among youth soccer players from 12 to 17 years old. The sample consisted of 3689 tactical actions performed by 48 soccer players in three age categories: under 13 (U-13), under 15 (U-15), and under 17 (U-17). Tactical performance was measured using the System of Tactical Assessment in Soccer (FUT-SAT). The Kruskal Wallis, Mann-Whitney U, Friedman, Wilcoxon, and Cohen’s Kappa tests were used in the study analysis. The results showed that the principles of “offensive coverage” (p = 0.01) and “concentration” (p = 0.04) were performed more frequently by the U-17 players than the U-13 players. The tactical principles “width and length” (p < 0.05) and “defensive unit” (p < 0.05) were executed more frequently by younger soccer players. It can be concluded that the frequency with which fundamental tactical principles are performed varies between the gaming categories, which implies that there is valuation of defensive security and a progressive increase in “offensive coverage” caused by increased confidence and security in offensive actions. PMID:28828091

Fundamental Tactical Principles of Soccer: A Comparison of Different Age Groups.

PubMed

Borges, Paulo Henrique; Guilherme, José; Rechenchosky, Leandro; da Costa, Luciane Cristina Arantes; Rinadi, Wilson

2017-09-01

The fundamental tactical principles of the game of soccer represent a set of action rules that guide behaviours related to the management of game space. The aim of this study was to compare the performance of fundamental offensive and defensive tactical principles among youth soccer players from 12 to 17 years old. The sample consisted of 3689 tactical actions performed by 48 soccer players in three age categories: under 13 (U-13), under 15 (U-15), and under 17 (U-17). Tactical performance was measured using the System of Tactical Assessment in Soccer (FUT-SAT). The Kruskal Wallis, Mann-Whitney U, Friedman, Wilcoxon, and Cohen's Kappa tests were used in the study analysis. The results showed that the principles of "offensive coverage" (p = 0.01) and "concentration" (p = 0.04) were performed more frequently by the U-17 players than the U-13 players. The tactical principles "width and length" (p < 0.05) and "defensive unit" (p < 0.05) were executed more frequently by younger soccer players. It can be concluded that the frequency with which fundamental tactical principles are performed varies between the gaming categories, which implies that there is valuation of defensive security and a progressive increase in "offensive coverage" caused by increased confidence and security in offensive actions.

Modified Universal Design Survey: Enhancing Operability of Launch Vehicle Ground Crew Worksites

NASA Technical Reports Server (NTRS)

Blume, Jennifer L.

2010-01-01

Operability is a driving requirement for next generation space launch vehicles. Launch site ground operations include numerous operator tasks to prepare the vehicle for launch or to perform preflight maintenance. Ensuring that components requiring operator interaction at the launch site are designed for optimal human use is a high priority for operability. To promote operability, a Design Quality Evaluation Survey based on Universal Design framework was developed to support Human Factors Engineering (HFE) evaluation for NASA s launch vehicles. Universal Design per se is not a priority for launch vehicle processing however; applying principles of Universal Design will increase the probability of an error free and efficient design which promotes operability. The Design Quality Evaluation Survey incorporates and tailors the seven Universal Design Principles and adds new measures for Safety and Efficiency. Adapting an approach proven to measure Universal Design Performance in Product, each principle is associated with multiple performance measures which are rated with the degree to which the statement is true. The Design Quality Evaluation Survey was employed for several launch vehicle ground processing worksite analyses. The tool was found to be most useful for comparative judgments as opposed to an assessment of a single design option. It provided a useful piece of additional data when assessing possible operator interfaces or worksites for operability.

Still Warm but Getting Colder: Changing Ethnic Identity of Post-Soviet Jewry

ERIC Educational Resources Information Center

Nosenko-Stein, Elena

2014-01-01

For many centuries, "being a Jew" was equivalent to "performing the ceremonial laws of Judaism." Thus, ethnic and confessional principles coincided and reinforced the cultural identity of Jewry as an entity. Strong self-identification and in-group solidarity supported the high "ethnic temperature" of this group. The…

The effects of display-control I/O, compatibility, and integrality on dual-task performance and subjective workload

NASA Technical Reports Server (NTRS)

Tsang, Pamela S.; Hart, Sandra G.; Vidulich, Michael A.

1987-01-01

The utility of speech technology was evaluated in terms of three dual task principles: resource competition between the time shared tasks, stimulus central processing response compatibility, and task integrality. Empirical support for these principles was reviewed. Two studies investigating the interactive effects of the three principles were described. Objective performance and subjective workload ratings for both single and dual tasks were examined. It was found that the single task measures were not necessarily good predictors for the dual task measures. It was shown that all three principles played an important role in determining an optimal task configuration. This was reflected in both the performance measures and the subjective measures. Therefore, consideration of all three principles is required to insure proper use of speech technology in a complex environment.

Application and research of artificial water mist on photoelectric interference

NASA Astrophysics Data System (ADS)

He, Yuejun; Ren, Baolin

2018-04-01

Water mist is a new type of photoelectric interfering material. It can exert a strong interference and shielding effect on infrared light, laser and radar wave through scattering, reflection, refraction and absorption. Based on this, this paper illustrates the application of an artificial high pressure water mist technology in infrared interference system. First, the operating principle of the infrared interference system is introduced. Next, the design principle of self-excited rotary vortex nozzle, the key part of the system, is elaborated. Then, the calculation of the main control parameters of the system is clarified. In the end, the paper verifies interference and shielding effect of the system by experiment. Experiment shows that the interference system can significantly reduce infrared signature of the target, featuring excellent infrared interference performance and high practical value.

Using spatial principles to optimize distributed computing for enabling the physical science discoveries

PubMed Central

Yang, Chaowei; Wu, Huayi; Huang, Qunying; Li, Zhenlong; Li, Jing

2011-01-01

Contemporary physical science studies rely on the effective analyses of geographically dispersed spatial data and simulations of physical phenomena. Single computers and generic high-end computing are not sufficient to process the data for complex physical science analysis and simulations, which can be successfully supported only through distributed computing, best optimized through the application of spatial principles. Spatial computing, the computing aspect of a spatial cyberinfrastructure, refers to a computing paradigm that utilizes spatial principles to optimize distributed computers to catalyze advancements in the physical sciences. Spatial principles govern the interactions between scientific parameters across space and time by providing the spatial connections and constraints to drive the progression of the phenomena. Therefore, spatial computing studies could better position us to leverage spatial principles in simulating physical phenomena and, by extension, advance the physical sciences. Using geospatial science as an example, this paper illustrates through three research examples how spatial computing could (i) enable data intensive science with efficient data/services search, access, and utilization, (ii) facilitate physical science studies with enabling high-performance computing capabilities, and (iii) empower scientists with multidimensional visualization tools to understand observations and simulations. The research examples demonstrate that spatial computing is of critical importance to design computing methods to catalyze physical science studies with better data access, phenomena simulation, and analytical visualization. We envision that spatial computing will become a core technology that drives fundamental physical science advancements in the 21st century. PMID:21444779

Using spatial principles to optimize distributed computing for enabling the physical science discoveries.

PubMed

Yang, Chaowei; Wu, Huayi; Huang, Qunying; Li, Zhenlong; Li, Jing

2011-04-05

Contemporary physical science studies rely on the effective analyses of geographically dispersed spatial data and simulations of physical phenomena. Single computers and generic high-end computing are not sufficient to process the data for complex physical science analysis and simulations, which can be successfully supported only through distributed computing, best optimized through the application of spatial principles. Spatial computing, the computing aspect of a spatial cyberinfrastructure, refers to a computing paradigm that utilizes spatial principles to optimize distributed computers to catalyze advancements in the physical sciences. Spatial principles govern the interactions between scientific parameters across space and time by providing the spatial connections and constraints to drive the progression of the phenomena. Therefore, spatial computing studies could better position us to leverage spatial principles in simulating physical phenomena and, by extension, advance the physical sciences. Using geospatial science as an example, this paper illustrates through three research examples how spatial computing could (i) enable data intensive science with efficient data/services search, access, and utilization, (ii) facilitate physical science studies with enabling high-performance computing capabilities, and (iii) empower scientists with multidimensional visualization tools to understand observations and simulations. The research examples demonstrate that spatial computing is of critical importance to design computing methods to catalyze physical science studies with better data access, phenomena simulation, and analytical visualization. We envision that spatial computing will become a core technology that drives fundamental physical science advancements in the 21st century.

Accelerated Discovery of High-Refractive-Index Polymers Using First-Principles Modeling, Virtual High-Throughput Screening, and Data Mining

NASA Astrophysics Data System (ADS)

Afzal, Mohammad Atif Faiz; Cheng, Chong; Hachmann, Johannes

Organic materials with refractive index (RI) values higher than 1.7 have attracted considerable interest in recent years due to the tremendous potential for their application in optical, optometric, and optoelectronic devices, and thus for shaping technological innovation in numerous related areas. Our work is concerned with creating predictive models for the optical properties of organic polymers, which will guide our experimentalist partners and allow them to target the most promising candidates. The RI model is developed based on a synergistic combination of first-principles electronic structure theory and machine learning techniques. The RI values predicted for common polymers using this model are in very good agreement with the experimental values. We also benchmark different DFT approximations along with various basis sets for their predictive performance in this model. We demonstrate that this combination of first-principles and data modeling is both successful and highly economical in determining the RI values of a wide range of organic polymers. To accelerate the development process, we cast this modeling approach into the high-throughput screening, materials informatics, and rational design framework that is developed in the group. This framework is a powerful tool and has shown to be highly promising for rapidly identifying polymer candidates with exceptional RI values as well as discovering design rules for advanced materials.

Simultaneous Dual Species Matter Wave Interferometry

NASA Astrophysics Data System (ADS)

Schlippert, Dennis; Albers, Henning; Richardson, Logan; Meiners, Christian; Hartwig, Jonas; Ertmer, Wolfgang; Rasel, Ernst

2014-05-01

We report on the first realization of a simultaneous 39K-87Rb-dual species matter wave interferometer measuring gravitational acceleration with the aim to test Einstein's Equivalence Principle (EEP). Compared to classical tests such as torsion pendulum experiments and Lunar Laser Ranging, chemical elements suitable for performing matter wave interferometry can provide complementary information. We show the performance of our apparatus and discuss current limitations and future improvements towards highly sensitive matter wave tests of EEP.

Organizing principles and management climate in high-performing municipal elderly care.

PubMed

Kajonius, Petri; Kazemi, Ali; Tengblad, Stefan

2016-01-01

Purpose - Previous research has shown that user-oriented care predicts older persons' satisfaction with care. What is yet to be researched is how senior management facilitates the implementation of user-oriented care. The purpose of this study is to investigate the organizing principles and management climate characterizing successful elderly care. Design/methodology/approach - The department in one highly ranked municipality was selected and compared with a more average municipality. On-site in-depth semi-structured interviews with department managers and participatory observations at managers' meetings were conducted in both municipalities. Findings - Results revealed three key principles for successful elderly care: organizing care from the viewpoint of the older person; recruiting and training competent and autonomous employees; instilling a vision for the mission that guides operations at all levels in the organization. Furthermore, using climate theory to interpret the empirical material, in the highly successful municipality the management climate was characterized by affective support and cognitive autonomy, in contrast to a more instrumental work climate primarily focusing on organizational structure and doing the right things characterizing the more average municipality. Originality/value - The authors suggest that guiding organizing principles are intertwined with management climate and that there are multiple perspectives that must be considered by the management, that is, the views of the older persons, the co-workers and the mission. These results can guide future care quality developments, and increase the understanding of the importance of organizational climate at the senior management level.

Resolving phase stability in the Ti-O binary with first-principles statistical mechanics methods

NASA Astrophysics Data System (ADS)

Gunda, N. S. Harsha; Puchala, Brian; Van der Ven, Anton

2018-03-01

The Ti-O system consists of a multitude of stable and metastable oxides that are used in wide ranging applications. In this work we investigate phase stability in the Ti-O binary from first principles. We perform a systematic search for ground state structures as a function of oxygen concentration by considering oxygen-vacancy and/or titanium-vacancy orderings over four parent crystal structures: (i) hcp Ti, (ii) ω -Ti, (iii) rocksalt, and (iv) hcp oxygen containing interstitial titanium. We explore phase stability at finite temperature using cluster expansion Hamiltonians and Monte Carlo simulations. The calculations predict a high oxygen solubility in hcp Ti and the stability of suboxide phases that undergo order-disorder transitions upon heating. Vacancy ordered rocksalt phases are also predicted at low temperature that disorder to form an extended solid solution at high temperatures. Predicted stable and metastable phase diagrams are qualitatively consistent with experimental observations, however, important discrepancies are revealed between first-principles density functional theory predictions of phase stability and the current understanding of phase stability in this system.

Setup and evaluation of a sensor tilting system for dimensional micro- and nanometrology

NASA Astrophysics Data System (ADS)

Schuler, Alexander; Weckenmann, Albert; Hausotte, Tino

2014-06-01

Sensors in micro- and nanometrology show their limits if the measurement objects and surfaces feature high aspect ratios, high curvature and steep surface angles. Their measurable surface angle is limited and an excess leads to measurement deviation and not detectable surface points. We demonstrate a principle to adapt the sensor's working angle during the measurement keeping the sensor in its optimal working angle. After the simulation of the principle, a hardware prototype was realized. It is based on a rotary kinematic chain with two rotary degrees of freedom, which extends the measurable surface angle to ±90° and is combined with a nanopositioning and nanomeasuring machine. By applying a calibration procedure with a quasi-tactile 3D sensor based on electrical near-field interaction the systematic position deviation of the kinematic chain is reduced. The paper shows for the first time the completed setup and integration of the prototype, the performance results of the calibration, the measurements with the prototype and the tilting principle, and finishes with the interpretation and feedback of the practical results.

Analysis of superconducting electromagnetic finite elements based on a magnetic vector potential variational principle

NASA Technical Reports Server (NTRS)

Schuler, James J.; Felippa, Carlos A.

1991-01-01

Electromagnetic finite elements are extended based on a variational principle that uses the electromagnetic four potential as primary variable. The variational principle is extended to include the ability to predict a nonlinear current distribution within a conductor. The extension of this theory is first done on a normal conductor and tested on two different problems. In both problems, the geometry remains the same, but the material properties are different. The geometry is that of a 1-D infinite wire. The first problem is merely a linear control case used to validate the new theory. The second problem is made up of linear conductors with varying conductivities. Both problems perform well and predict current densities that are accurate to within a few ten thousandths of a percent of the exact values. The fourth potential is then removed, leaving only the magnetic vector potential, and the variational principle is further extended to predict magnetic potentials, magnetic fields, the number of charge carriers, and the current densities within a superconductor. The new element produces good results for the mean magnetic field, the vector potential, and the number of superconducting charge carriers despite a relatively high system condition number. The element did not perform well in predicting the current density. Numerical problems inherent to this formulation are explored and possible remedies to produce better current predicting finite elements are presented.

First-principles simulation on Seebeck coefficient in silicon nanowires

NASA Astrophysics Data System (ADS)

Nakamura, Koichi

2017-06-01

The Seebeck coefficients of silicon nanowires (SiNWs) were simulated on the basis of first-principles calculation using various atomistic structure models. The electronic band structures of fully hydrogen-terminated SiNW models give the correct image of quantum mechanical confinement from bulk silicon to SiNW for each axial direction, and the change in the density of states by dimensional reduction to SiNW enhances the thermoelectric performance in terms of the Seebeck coefficient, compared with those of bulk silicon and silicon nanosheets. The uniaxial tensile strain for the SiNW models does not strongly affect the Seebeck coefficient even for the SiNW system with giant piezoresistivity. In contrast, dangling bonds on a wire wall sharply reduce the Seebeck coefficient of SiNW and totally degrade thermoelectric performance from the viewpoint of the power factor. The exclusion of dangling bonds is a key element for the design and application of high-performance thermoelectric nanowires of semiconducting materials.

Blind Channel Equalization with Colored Source Based on Constrained Optimization Methods

NASA Astrophysics Data System (ADS)

Wang, Yunhua; DeBrunner, Linda; DeBrunner, Victor; Zhou, Dayong

2008-12-01

Tsatsanis and Xu have applied the constrained minimum output variance (CMOV) principle to directly blind equalize a linear channel—a technique that has proven effective with white inputs. It is generally assumed in the literature that their CMOV method can also effectively equalize a linear channel with a colored source. In this paper, we prove that colored inputs will cause the equalizer to incorrectly converge due to inadequate constraints. We also introduce a new blind channel equalizer algorithm that is based on the CMOV principle, but with a different constraint that will correctly handle colored sources. Our proposed algorithm works for channels with either white or colored inputs and performs equivalently to the trained minimum mean-square error (MMSE) equalizer under high SNR. Thus, our proposed algorithm may be regarded as an extension of the CMOV algorithm proposed by Tsatsanis and Xu. We also introduce several methods to improve the performance of our introduced algorithm in the low SNR condition. Simulation results show the superior performance of our proposed methods.

Applying lessons from commercial aviation safety and operations to resuscitation.

PubMed

Ornato, Joseph P; Peberdy, Mary Ann

2014-02-01

Both commercial aviation and resuscitation are complex activities in which team members must respond to unexpected emergencies in a consistent, high quality manner. Lives are at stake in both activities and the two disciplines have similar leadership structures, standard setting processes, training methods, and operational tools. Commercial aviation crews operate with remarkable consistency and safety, while resuscitation team performance and outcomes are highly variable. This commentary provides the perspective of two physician-pilots showing how commercial aviation training, operations, and safety principles can be adapted to resuscitation team training and performance. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Measurement of optical to electrical and electrical to optical delays with ps-level uncertainty.

PubMed

Peek, H Z; Pinkert, T J; Jansweijer, P P M; Koelemeij, J C J

2018-05-28

We present a new measurement principle to determine the absolute time delay of a waveform from an optical reference plane to an electrical reference plane and vice versa. We demonstrate a method based on this principle with 2 ps uncertainty. This method can be used to perform accurate time delay determinations of optical transceivers used in fiber-optic time-dissemination equipment. As a result the time scales in optical and electrical domain can be related to each other with the same uncertainty. We expect this method will be a new breakthrough in high-accuracy time transfer and absolute calibration of time-transfer equipment.

Three Principles of Perception for Instructional Interface Design.

ERIC Educational Resources Information Center

Lohr, Linda L.

2000-01-01

Discusses graphical user interfaces used for instructional purposes in educational environments, which promote learning goals, and in support environments, which promote performance goals. Explains three key principles of perception and gives guidelines for their use, including the figure/ground principle, the hierarchy principle, and the gestalt…

TRIZ theory in NEA photocathode preparation system

NASA Astrophysics Data System (ADS)

Qiao, Jianliang; Huang, Dayong; Li, Xiangjiang; Gao, Youtang

2016-09-01

The solutions to the engineering problems were provided according to the innovation principle based on the theory of TRIZ. The ultra high vacuum test and evaluation system for the preparation of negative electron affinity (NEA) photocathode has the characteristics of complex structure and powerful functions. Segmentation principle, advance function principle, curved surface principle, dynamic characteristics principle and nested principle adopted by the design of ultra high vacuum test and evaluation system for cathode preparation were analyzed. The applications of the physical contradiction and the substance-field analysis method of the theory of TRIZ in the cathode preparation ultra high vacuum test and evaluation system were discussed.

Airborne ultrasound applied to anthropometry--physical and technical principles.

PubMed

Lindström, K; Mauritzson, L; Benoni, G; Willner, S

1983-01-01

Airborne ultrasound has been utilized for remote measurement of distance, direction, size, form, volume and velocity. General anthropometrical measurements are performed with a newly constructed real-time linear array scanner. To make full use of the method, we expect a rapid development of high-frequency ultrasound transducers for use in air.

Architectural Principles and Experimentation of Distributed High Performance Virtual Clusters

ERIC Educational Resources Information Center

Younge, Andrew J.

2016-01-01

With the advent of virtualization and Infrastructure-as-a-Service (IaaS), the broader scientific computing community is considering the use of clouds for their scientific computing needs. This is due to the relative scalability, ease of use, advanced user environment customization abilities, and the many novel computing paradigms available for…

Rethinking edTPA: The Use of InTASC Principles and Standards

ERIC Educational Resources Information Center

Kuo, Nai-Cheng

2018-01-01

The Interstate Teacher Assessment and Support Consortium (InTASC) Model Core Teaching Standards and Learning Progressions for Teachers 1.0, developed by the Council of Chief State School Officers (CCSSO, 2013) in the United States, provide a set of expectations for essential knowledge, critical disposition, and performance needed for high-quality…

Improving Service Quality: Achieving High Performance in the Public and Private Sectors.

ERIC Educational Resources Information Center

Milakovich, Michael E.

Quality-improvement principles are a sound means to respond to customer needs. However, when various quality and productivity theories and methods are applied, it is very difficult to consistently deliver quality results, especially in quasi-monopolistic, non-competitive, and regulated environments. This book focuses on quality-improvement methods…

Matching Judicial Supervision to Clients' Risk Status in Drug Court

ERIC Educational Resources Information Center

Marlowe, Douglas B.; Festinger, David S.; Lee, Patricia A.; Dugosh, Karen L.; Benasutti, Kathleen M.

2006-01-01

This article reports outcomes from a program of experimental research evaluating the risk principle in drug courts. Prior studies revealed that participants who were high risk and had (a) antisocial personality disorder or (b) a prior history of drug abuse treatment performed better in drug court when scheduled to attend biweekly judicial status…

Analysis of Investigational Drugs in Biological Fluids - Method Development and Routine Assay

DTIC Science & Technology

1994-08-14

Principles of Internal Medicine, Tenth edition. Edited by Petersdorf, R.G.; Adams , R.P.; Braunwald, E.; Isselbacher K.J.; Martin, J.B.; and Wilson, J.D...artelinic acid in blood plasma by high-performance liquid chromatography. 1. Chromatogr., 1989, 495, 167-77. 60Lin ET, Benet LZ, Upton RA, Levai F

Finding One's Voice: The Pacesetter Model for More Equitable Assessment.

ERIC Educational Resources Information Center

Badger, Elizabeth

1996-01-01

Describes the College Board's Pacesetter Program, high school courses developed using principles of ongoing performance testing and portfolios, standards, and curriculum. The model is illustrated in a description of the Voices of Modern Culture language arts course. Argues that this assessment process has systemic validity and is more relevant to…

Feasibility of introducing ferromagnetic materials to onboard bulk high-Tc superconductors to enhance the performance of present maglev systems

NASA Astrophysics Data System (ADS)

Deng, Zigang; Wang, Jiasu; Zheng, Jun; Zhang, Ya; Wang, Suyu

2013-02-01

Performance improvement is a long-term research task for the promotion of practical application of promising high-temperature superconducting (HTS) magnetic levitation (maglev) vehicle technologies. We studied the feasibility to enhance the performance of present HTS Maglev systems by introducing ferromagnetic materials to onboard bulk superconductors. The principle here is to make use of the high magnetic permeability of ferromagnetic materials to alter the flux distribution of the permanent magnet guideway for the enhancement of magnetic field density at the position of the bulk superconductors. Ferromagnetic iron plates were added to the upper surface of bulk superconductors and their geometric and positioning effects on the maglev performance were investigated experimentally. Results show that the guidance performance (stability) was enhanced greatly for a particular setup when compared to the present maglev system which is helpful in the application where large guidance forces are needed such as maglev tracks with high degrees of curves.

Photochemistry on soft-glass hollow-core photonic crystal fibre

NASA Astrophysics Data System (ADS)

Cubillas, Ana M.; Jiang, Xin; Euser, Tijmen G.; Taccardi, Nicola; Etzold, Bastian J. M.; Wasserscheid, Peter; Russell, Philip St. J.

2014-05-01

Hollow-core photonic crystal fibre (HC-PCF) offers strong light confinement and long interaction lengths in an optofluidic channel. These unique advantages have motivated its recent use as a highly efficient and versatile microreactor for liquid-phase photochemistry and catalysis. In this work, we use a soft-glass HC-PCF to carry out photochemical experiments in a high-index solvent such as toluene. The high-intensity and strong confinement in the fibre is demonstrated to enhance the performance of a proof-of-principle photolysis reaction.

Principles for the formation of an effective concept of multifunctional high-rise construction investment projects

NASA Astrophysics Data System (ADS)

Beliakov, Sergei

2018-03-01

Investment projects of high-rise construction have a number of features that determine specific risks and additional opportunities that require analysis and accounting in the formation of an effective project concept. The most significant features of high-rise construction include long construction time, complexity of technical and technological solutions, complexity of decisions on the organization of construction and operation, high cost of construction and operation, complexity in determining the ratio of areas designed to accommodate different functional areas, when organizing and coordinating the operation of the facility, with internal zoning. Taking into account the specificity of high-rise construction, among the factors determining the effectiveness of projects, it is advisable to consider as key factors: organizational, technological and investment factors. Within the framework of the article, the author singled out key particular functions for each group of factors under consideration, and also developed a system of principles for the formation of an effective concept of multifunctional high-rise construction investment projects, including the principle of logistic efficiency, the principle of optimal functional zoning, the principle of efficiency of equipment use, the principle of optimizing technological processes, the principle maximization of income, the principle of fund management, the principle of risk management . The model of formation of an effective concept of investment projects of multifunctional high-rise construction developed by the author can contribute to the development of methodological tools in the field of managing the implementation of high-rise construction projects, taking into account their specificity in the current economic conditions.

Yesterday's Extraordinary Research Yields Today's Ordinary Principles

ERIC Educational Resources Information Center

Thomas, Mary Norris

2005-01-01

Ordinary performance improvement tips, techniques, and principles that are taken for granted today have their roots in extraordinary research. Today, the learning principle that states that things that occur together tend to be recalled together is widely accepted, and this principle of association as an instructional technique is often used. How…

Principles of project management

NASA Technical Reports Server (NTRS)

1982-01-01

The basic principles of project management as practiced by NASA management personnel are presented. These principles are given as ground rules and guidelines to be used in the performance of research, development, construction or operational assignments.

Petascale supercomputing to accelerate the design of high-temperature alloys

DOE PAGES

Shin, Dongwon; Lee, Sangkeun; Shyam, Amit; ...

2017-10-25

Recent progress in high-performance computing and data informatics has opened up numerous opportunities to aid the design of advanced materials. Herein, we demonstrate a computational workflow that includes rapid population of high-fidelity materials datasets via petascale computing and subsequent analyses with modern data science techniques. We use a first-principles approach based on density functional theory to derive the segregation energies of 34 microalloying elements at the coherent and semi-coherent interfaces between the aluminium matrix and the θ'-Al 2Cu precipitate, which requires several hundred supercell calculations. We also perform extensive correlation analyses to identify materials descriptors that affect the segregation behaviourmore » of solutes at the interfaces. Finally, we show an example of leveraging machine learning techniques to predict segregation energies without performing computationally expensive physics-based simulations. As a result, the approach demonstrated in the present work can be applied to any high-temperature alloy system for which key materials data can be obtained using high-performance computing.« less

Petascale supercomputing to accelerate the design of high-temperature alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Dongwon; Lee, Sangkeun; Shyam, Amit

Recent progress in high-performance computing and data informatics has opened up numerous opportunities to aid the design of advanced materials. Herein, we demonstrate a computational workflow that includes rapid population of high-fidelity materials datasets via petascale computing and subsequent analyses with modern data science techniques. We use a first-principles approach based on density functional theory to derive the segregation energies of 34 microalloying elements at the coherent and semi-coherent interfaces between the aluminium matrix and the θ'-Al 2Cu precipitate, which requires several hundred supercell calculations. We also perform extensive correlation analyses to identify materials descriptors that affect the segregation behaviourmore » of solutes at the interfaces. Finally, we show an example of leveraging machine learning techniques to predict segregation energies without performing computationally expensive physics-based simulations. As a result, the approach demonstrated in the present work can be applied to any high-temperature alloy system for which key materials data can be obtained using high-performance computing.« less

Petascale supercomputing to accelerate the design of high-temperature alloys

NASA Astrophysics Data System (ADS)

Shin, Dongwon; Lee, Sangkeun; Shyam, Amit; Haynes, J. Allen

2017-12-01

Recent progress in high-performance computing and data informatics has opened up numerous opportunities to aid the design of advanced materials. Herein, we demonstrate a computational workflow that includes rapid population of high-fidelity materials datasets via petascale computing and subsequent analyses with modern data science techniques. We use a first-principles approach based on density functional theory to derive the segregation energies of 34 microalloying elements at the coherent and semi-coherent interfaces between the aluminium matrix and the θ‧-Al2Cu precipitate, which requires several hundred supercell calculations. We also perform extensive correlation analyses to identify materials descriptors that affect the segregation behaviour of solutes at the interfaces. Finally, we show an example of leveraging machine learning techniques to predict segregation energies without performing computationally expensive physics-based simulations. The approach demonstrated in the present work can be applied to any high-temperature alloy system for which key materials data can be obtained using high-performance computing.

Progress in performance enhancement methods for capacitive silicon resonators

NASA Astrophysics Data System (ADS)

Van Toan, Nguyen; Ono, Takahito

2017-11-01

In this paper, we review the progress in recent studies on the performance enhancement methods for capacitive silicon resonators. We provide information on various fabrication technologies and design considerations that can be employed to improve the performance of capacitive silicon resonators, including low motional resistance, small insertion loss, and high quality factor (Q). This paper contains an overview of device structures and working principles, fabrication technologies consisting of hermetic packaging, deep reactive-ion etching and neutral beam etching, and design considerations including mechanically coupled, movable electrode structures and piezoresistive heat engines.

Small spacecraft power and thermal subsystems

NASA Technical Reports Server (NTRS)

Eakman, D.; Lambeck, R.; Mackowski, M.; Slifer, L., Jr.

1994-01-01

This white paper provides a general guide to the conceptual design of satellite power and thermal control subsystems with special emphasis on the unique design aspects associated with small satellites. The operating principles of these technologies are explained and performance characteristics of current and projected components are provided. A tutorial is presented on the design process for both power and thermal subsystems, with emphasis on unique issues relevant to small satellites. The ability of existing technology to meet future performance requirements is discussed. Conclusions and observations are presented that stress cost-effective, high-performance design solutions.

Unconventional Hamilton-type variational principle in phase space and symplectic algorithm

NASA Astrophysics Data System (ADS)

Luo, En; Huang, Weijiang; Zhang, Hexin

2003-06-01

By a novel approach proposed by Luo, the unconventional Hamilton-type variational principle in phase space for elastodynamics of multidegree-of-freedom system is established in this paper. It not only can fully characterize the initial-value problem of this dynamic, but also has a natural symplectic structure. Based on this variational principle, a symplectic algorithm which is called a symplectic time-subdomain method is proposed. A non-difference scheme is constructed by applying Lagrange interpolation polynomial to the time subdomain. Furthermore, it is also proved that the presented symplectic algorithm is an unconditionally stable one. From the results of the two numerical examples of different types, it can be seen that the accuracy and the computational efficiency of the new method excel obviously those of widely used Wilson-θ and Newmark-β methods. Therefore, this new algorithm is a highly efficient one with better computational performance.

A survey of parametrized variational principles and applications to computational mechanics

NASA Technical Reports Server (NTRS)

Felippa, Carlos A.

1993-01-01

This survey paper describes recent developments in the area of parametrized variational principles (PVP's) and selected applications to finite-element computational mechanics. A PVP is a variational principle containing free parameters that have no effect on the Euler-Lagrange equations. The theory of single-field PVP's based on gauge functions (also known as null Lagrangians) is a subset of the inverse problem of variational calculus that has limited value. On the other hand, multifield PVP's are more interesting from theoretical and practical standpoints. Following a tutorial introduction, the paper describes the recent construction of multifield PVP's in several areas of elasticity and electromagnetics. It then discusses three applications to finite-element computational mechanics: the derivation of high-performance finite elements, the development of element-level error indicators, and the constructions of finite element templates. The paper concludes with an overview of open research areas.

21 CFR 814.39 - PMA supplements.

Code of Federal Regulations, 2014 CFR

2014-04-01

... sterilization procedures. (5) Changes in packaging. (6) Changes in the performance or design specifications, circuits, components, ingredients, principle of operation, or physical layout of the device. (7) Extension... the performance or design specifications, circuits, components, ingredients, principles of operation...

GPU Acceleration of the Locally Selfconsistent Multiple Scattering Code for First Principles Calculation of the Ground State and Statistical Physics of Materials

NASA Astrophysics Data System (ADS)

Eisenbach, Markus

The Locally Self-consistent Multiple Scattering (LSMS) code solves the first principles Density Functional theory Kohn-Sham equation for a wide range of materials with a special focus on metals, alloys and metallic nano-structures. It has traditionally exhibited near perfect scalability on massively parallel high performance computer architectures. We present our efforts to exploit GPUs to accelerate the LSMS code to enable first principles calculations of O(100,000) atoms and statistical physics sampling of finite temperature properties. Using the Cray XK7 system Titan at the Oak Ridge Leadership Computing Facility we achieve a sustained performance of 14.5PFlop/s and a speedup of 8.6 compared to the CPU only code. This work has been sponsored by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Material Sciences and Engineering Division and by the Office of Advanced Scientific Computing. This work used resources of the Oak Ridge Leadership Computing Facility, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725.

High-performance multi-channel fiber-based absolute distance measuring interferometer system

NASA Astrophysics Data System (ADS)

Deck, Leslie L.

2009-08-01

I describe the principle of operation and performance of a fiber-based absolute distance measuring interferometer system with 60 independent simultaneous channels. The system was designed for demanding applications requiring passive, electrically immune sensors with an extremely long MTTF. In addition to providing better than 0.3nm measurement repeatability at 5KHz for all channels, the system demonstrated absolute distance uncertainty of less than 5nm over a 500 micron measurement range.

Pressure induced structural phase transition of OsB 2: First-principles calculations

NASA Astrophysics Data System (ADS)

Ren, Fengzhu; Wang, Yuanxu; Lo, V. C.

2010-04-01

Orthorhombic OsB 2 was synthesized at 1000 °C and its compressibility was measured by using the high-pressure X-ray diffraction in a Diacell diamond anvil cell from ambient pressure to 32 GPa [R.W. Cumberland, et al. (2005)]. First-principles calculations were performed to study the possibility of the phase transition of OsB 2. An analysis of the calculated enthalpy shows that orthorhombic OsB 2 can transfer to the hexagonal phase at 10.8 GPa. The calculated results with the quasi-harmonic approximation indicate that this phase transition pressure is little affected by the thermal effect. The calculated phonon band structure shows that the hexagonal P 6 3/ mmc structure (high-pressure phase) is stable for OsB 2. We expect the phase transition can be further confirmed by the experimental work.

New classes of piezoelectrics, ferroelectrics, and antiferroelectrics by first-principles high-throughput materials design

NASA Astrophysics Data System (ADS)

Bennett, Joseph

2013-03-01

Functional materials, such as piezoelectrics, ferroelectrics, and antiferroelectrics, exhibit large changes with applied fields and stresses. This behavior enables their incorporation into a wide variety of devices in technological fields such as energy conversion/storage and information processing/storage. Discovery of functional materials with improved performance or even new types of responses is thus not only a scientific challenge, but can have major impacts on society. In this talk I will review our efforts to uncover new families of functional materials using a combined crystallographic database/high-throughput first-principles approach. I will describe our work on the design and discovery of thousands of new functional materials, specifically the LiAlSi family as piezoelectrics, the LiGaGe family as ferroelectrics, and the MgSrSi family as antiferroelectrics.

Large-scale optimization-based non-negative computational framework for diffusion equations: Parallel implementation and performance studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Justin; Karra, Satish; Nakshatrala, Kalyana B.

It is well-known that the standard Galerkin formulation, which is often the formulation of choice under the finite element method for solving self-adjoint diffusion equations, does not meet maximum principles and the non-negative constraint for anisotropic diffusion equations. Recently, optimization-based methodologies that satisfy maximum principles and the non-negative constraint for steady-state and transient diffusion-type equations have been proposed. To date, these methodologies have been tested only on small-scale academic problems. The purpose of this paper is to systematically study the performance of the non-negative methodology in the context of high performance computing (HPC). PETSc and TAO libraries are, respectively, usedmore » for the parallel environment and optimization solvers. For large-scale problems, it is important for computational scientists to understand the computational performance of current algorithms available in these scientific libraries. The numerical experiments are conducted on the state-of-the-art HPC systems, and a single-core performance model is used to better characterize the efficiency of the solvers. Furthermore, our studies indicate that the proposed non-negative computational framework for diffusion-type equations exhibits excellent strong scaling for real-world large-scale problems.« less

Practical Approaches to Quality Improvement for Radiologists.

PubMed

Kelly, Aine Marie; Cronin, Paul

2015-10-01

Continuous quality improvement is a fundamental attribute of high-performing health care systems. Quality improvement is an essential component of health care, with the current emphasis on adding value. It is also a regulatory requirement, with reimbursements increasingly being linked to practice performance metrics. Practice quality improvement efforts must be demonstrated for credentialing purposes and for certification of radiologists in practice. Continuous quality improvement must occur for radiologists to remain competitive in an increasingly diverse health care market. This review provides an introduction to the main approaches available to undertake practice quality improvement, which will be useful for busy radiologists. Quality improvement plays multiple roles in radiology services, including ensuring and improving patient safety, providing a framework for implementing and improving processes to increase efficiency and reduce waste, analyzing and depicting performance data, monitoring performance and implementing change, enabling personnel assessment and development through continued education, and optimizing customer service and patient outcomes. The quality improvement approaches and underlying principles overlap, which is not surprising given that they all align with good patient care. The application of these principles to radiology practices not only benefits patients but also enhances practice performance through promotion of teamwork and achievement of goals. © RSNA, 2015.

Large-scale optimization-based non-negative computational framework for diffusion equations: Parallel implementation and performance studies

DOE PAGES

Chang, Justin; Karra, Satish; Nakshatrala, Kalyana B.

2016-07-26

It is well-known that the standard Galerkin formulation, which is often the formulation of choice under the finite element method for solving self-adjoint diffusion equations, does not meet maximum principles and the non-negative constraint for anisotropic diffusion equations. Recently, optimization-based methodologies that satisfy maximum principles and the non-negative constraint for steady-state and transient diffusion-type equations have been proposed. To date, these methodologies have been tested only on small-scale academic problems. The purpose of this paper is to systematically study the performance of the non-negative methodology in the context of high performance computing (HPC). PETSc and TAO libraries are, respectively, usedmore » for the parallel environment and optimization solvers. For large-scale problems, it is important for computational scientists to understand the computational performance of current algorithms available in these scientific libraries. The numerical experiments are conducted on the state-of-the-art HPC systems, and a single-core performance model is used to better characterize the efficiency of the solvers. Furthermore, our studies indicate that the proposed non-negative computational framework for diffusion-type equations exhibits excellent strong scaling for real-world large-scale problems.« less

Transfer and retrieval of optical coherence to strain-compensated quantum dots using a heterodyne photon-echo technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Kazumasa; Ishi-Hayase, Junko; Akahane, Kouichi

2013-12-04

We performed the proof-of-principle demonstration of photon-echo quantum memory using strain-compensated InAs quantum dot ensemble in the telecommunication wavelength range. We succeeded in transfer and retrieval of relative phase of a time-bin pulse with a high fidelity. Our demonstration suggests the possibility of realizing ultrabroadband, high time-bandwidth products, multi-mode quantum memory which is operable at telecommunication wavelength.

Adaptation of Combustion Principles to Aircraft Propulsion. Volume I; Basic Considerations in the Combustion of Hydrocarbon Fuels with Air

NASA Technical Reports Server (NTRS)

Barnett, Henry C (Editor); Hibbard, Robert R (Editor)

1955-01-01

The report summarizes source material on combustion for flight-propulsion engineers. First, several chapters review fundamental processes such as fuel-air mixture preparation, gas flow and mixing, flammability and ignition, flame propagation in both homogenous and heterogenous media, flame stabilization, combustion oscillations, and smoke and carbon formation. The practical significance and the relation of these processes to theory are presented. A second series of chapters describes the observed performance and design problems of engine combustors of the principal types. An attempt is made to interpret performance in terms of the fundamental processes and theories previously reviewed. Third, the design of high-speed combustion systems is discussed. Combustor design principles that can be established from basic considerations and from experience with actual combustors are described. Finally, future requirements for aircraft engine combustion systems are examined.

Organization of feed-forward loop motifs reveals architectural principles in natural and engineered networks.

PubMed

Gorochowski, Thomas E; Grierson, Claire S; di Bernardo, Mario

2018-03-01

Network motifs are significantly overrepresented subgraphs that have been proposed as building blocks for natural and engineered networks. Detailed functional analysis has been performed for many types of motif in isolation, but less is known about how motifs work together to perform complex tasks. To address this issue, we measure the aggregation of network motifs via methods that extract precisely how these structures are connected. Applying this approach to a broad spectrum of networked systems and focusing on the widespread feed-forward loop motif, we uncover striking differences in motif organization. The types of connection are often highly constrained, differ between domains, and clearly capture architectural principles. We show how this information can be used to effectively predict functionally important nodes in the metabolic network of Escherichia coli . Our findings have implications for understanding how networked systems are constructed from motif parts and elucidate constraints that guide their evolution.

Chemical principles underpinning the performance of the metal-organic framework HKUST-1.

PubMed

Hendon, Christopher H; Walsh, Aron

2015-07-15

A common feature of multi-functional metal-organic frameworks is a metal dimer in the form of a paddlewheel, as found in the structure of Cu 3 ( btc ) 2 (HKUST-1). The HKUST-1 framework demonstrates exceptional gas storage, sensing and separation, catalytic activity and, in recent studies, unprecedented ionic and electrical conductivity. These results are a promising step towards the real-world application of metal-organic materials. In this perspective, we discuss progress in the understanding of the electronic, magnetic and physical properties of HKUST-1, representative of the larger family of Cu···Cu containing metal-organic frameworks. We highlight the chemical interactions that give rise to its favourable properties, and which make this material well suited to a range of technological applications. From this analysis, we postulate key design principles for tailoring novel high-performance hybrid frameworks.

Chemical principles underpinning the performance of the metal–organic framework HKUST-1

PubMed Central

Hendon, Christopher H.

2015-01-01

A common feature of multi-functional metal–organic frameworks is a metal dimer in the form of a paddlewheel, as found in the structure of Cu3(btc)2 (HKUST-1). The HKUST-1 framework demonstrates exceptional gas storage, sensing and separation, catalytic activity and, in recent studies, unprecedented ionic and electrical conductivity. These results are a promising step towards the real-world application of metal–organic materials. In this perspective, we discuss progress in the understanding of the electronic, magnetic and physical properties of HKUST-1, representative of the larger family of Cu···Cu containing metal–organic frameworks. We highlight the chemical interactions that give rise to its favourable properties, and which make this material well suited to a range of technological applications. From this analysis, we postulate key design principles for tailoring novel high-performance hybrid frameworks. PMID:28706713

Increasing the efficiency of photon collection in LArTPCs: the ARAPUCA light trap

NASA Astrophysics Data System (ADS)

Cancelo, G.; Cavanna, F.; Escobar, C. O.; Kemp, E.; Machado, A. A.; Para, A.; Segreto, E.; Totani, D.; Warner, D.

2018-03-01

The Liquid Argon Time Projection Chambers (LArTPCs) are a choice for the next generation of large neutrino detectors due to their optimal performance in particle tracking and calorimetry. The detection of Argon scintillation light plays a crucial role in the event reconstruction as well as the time reference for non-beam physics such as supernovae neutrino detection and baryon number violation studies. In this contribution, we present the current R&D work on the ARAPUCA (Argon R&D Advanced Program at UNICAMP), a light trap device to enhance Ar scintillation light collection and thus the overall performance of LArTPCs. The ARAPUCA working principle is based on a suitable combination of dichroic filters and wavelength shifters to achieve a high efficiency in light collection. We discuss the operational principles, the last results of laboratory tests and the application of the ARAPUCA as the alternative photon detection system in the protoDUNE detector.

Organization of feed-forward loop motifs reveals architectural principles in natural and engineered networks

PubMed Central

Grierson, Claire S.

2018-01-01

Network motifs are significantly overrepresented subgraphs that have been proposed as building blocks for natural and engineered networks. Detailed functional analysis has been performed for many types of motif in isolation, but less is known about how motifs work together to perform complex tasks. To address this issue, we measure the aggregation of network motifs via methods that extract precisely how these structures are connected. Applying this approach to a broad spectrum of networked systems and focusing on the widespread feed-forward loop motif, we uncover striking differences in motif organization. The types of connection are often highly constrained, differ between domains, and clearly capture architectural principles. We show how this information can be used to effectively predict functionally important nodes in the metabolic network of Escherichia coli. Our findings have implications for understanding how networked systems are constructed from motif parts and elucidate constraints that guide their evolution. PMID:29670941

Hierarchical Coupling of First-Principles Molecular Dynamics with Advanced Sampling Methods.

PubMed

Sevgen, Emre; Giberti, Federico; Sidky, Hythem; Whitmer, Jonathan K; Galli, Giulia; Gygi, Francois; de Pablo, Juan J

2018-05-14

We present a seamless coupling of a suite of codes designed to perform advanced sampling simulations, with a first-principles molecular dynamics (MD) engine. As an illustrative example, we discuss results for the free energy and potential surfaces of the alanine dipeptide obtained using both local and hybrid density functionals (DFT), and we compare them with those of a widely used classical force field, Amber99sb. In our calculations, the efficiency of first-principles MD using hybrid functionals is augmented by hierarchical sampling, where hybrid free energy calculations are initiated using estimates obtained with local functionals. We find that the free energy surfaces obtained from classical and first-principles calculations differ. Compared to DFT results, the classical force field overestimates the internal energy contribution of high free energy states, and it underestimates the entropic contribution along the entire free energy profile. Using the string method, we illustrate how these differences lead to different transition pathways connecting the metastable minima of the alanine dipeptide. In larger peptides, those differences would lead to qualitatively different results for the equilibrium structure and conformation of these molecules.

Discovering Psychological Principles by Mining Naturally Occurring Data Sets.

PubMed

Goldstone, Robert L; Lupyan, Gary

2016-07-01

The very expertise with which psychologists wield their tools for achieving laboratory control may have had the unwelcome effect of blinding psychologists to the possibilities of discovering principles of behavior without conducting experiments. When creatively interrogated, a diverse range of large, real-world data sets provides powerful diagnostic tools for revealing principles of human judgment, perception, categorization, decision-making, language use, inference, problem solving, and representation. Examples of these data sets include patterns of website links, dictionaries, logs of group interactions, collections of images and image tags, text corpora, history of financial transactions, trends in twitter tag usage and propagation, patents, consumer product sales, performance in high-stakes sporting events, dialect maps, and scientific citations. The goal of this issue is to present some exemplary case studies of mining naturally existing data sets to reveal important principles and phenomena in cognitive science, and to discuss some of the underlying issues involved with conducting traditional experiments, analyses of naturally occurring data, computational modeling, and the synthesis of all three methods. Copyright © 2016 Cognitive Science Society, Inc.

Ab initio prediction of fast non-equilibrium transport of nascent polarons in SrI 2: a key to high-performance scintillation [First-principles study of hole polaron formation and migration in strontium iodide

DOE PAGES

Zhou, Fei; Sadigh, Babak; Aberg, Daniel; ...

2016-08-12

The excellent light yield proportionality of europium-doped strontium iodide (SrI 2:Eu) has resulted in state-of-the-art γ-ray detectors with remarkably high-energy resolution, far exceeding that of most halide compounds. In this class of materials, the formation of self-trapped hole polarons is very common. However, polaron formation is usually expected to limit carrier mobilities and has been associated with poor scintillator light-yield proportionality and resolution. Here using a recently developed first-principles method, we perform an unprecedented study of polaron transport in SrI 2, both for equilibrium polarons, as well as nascent polarons immediately following a self-trapping event. We propose a rationale formore » the unexpected high-energy resolution of SrI 2. We identify nine stable hole polaron configurations, which consist of dimerised iodine pairs with polaron-binding energies of up to 0.5 eV. They are connected by a complex potential energy landscape that comprises 66 unique nearest-neighbour migration paths. Ab initio molecular dynamics simulations reveal that a large fraction of polarons is born into configurations that migrate practically barrier free at room temperature. Consequently, carriers created during γ-irradiation can quickly diffuse away reducing the chance for nonlinear recombination, the primary culprit for non-proportionality and resolution reduction. We conclude that the flat, albeit complex, landscape for polaron migration in SrI 2 is a key for understanding its outstanding performance. This insight provides important guidance not only for the future development of high-performance scintillators but also of other materials, for which large polaron mobilities are crucial such as batteries and solid-state ionic conductors.« less

First principles calculations of La2O3/GaAs interface properties under biaxial strain and hydrostatic pressure

NASA Astrophysics Data System (ADS)

Shi, Li-Bin; Li, Ming-Biao; Xiu, Xiao-Ming; Liu, Xu-Yang; Zhang, Kai-Cheng; Li, Chun-Ran; Dong, Hai-Kuan

2017-04-01

La2O3 is a potential dielectric material with high permittivity (high-κ) for metal-oxide-semiconductor (MOS) devices. However, band offsets and oxide defects should still be concerned. Smaller band offsets and carrier traps increase leakage current, and degenerate performance of the devices. In this paper, the interface behaviors of La2O3/GaAs under biaxial strain and hydrostatic pressure are investigated, which is performed by first principles calculations based on density functional theory (DFT). Strain engineering is attempted to improve performance of the metal/La2O3/GaAs devices. First of all, we creatively realize band alignment of La2O3/GaAs interface under biaxial strain and hydrostatic pressure. The proper biaxial tensile strain can effectively increase valence band offsets (VBO) and conduction band offsets (CBO), which can be used to suppress leakage current. However, the VBO will decrease with the increase of hydrostatic pressure, indicating that performance of the devices is degenerated. Then, a direct tunneling leakage current model is used to investigate current and voltage characteristics of the metal/La2O3/GaAs. The impact of biaxial strain and hydrostatic pressure on leakage current is discussed. At last, formation energies and transition levels of oxygen interstitial (Oi) and oxygen vacancy (VO) in La2O3 are assessed. We investigate how they will affect performance of the devices.

Class Attendance and Performance in Principles of Economics

ERIC Educational Resources Information Center

Cohn, Elchanan; Johnson, Eric

2006-01-01

A sample of 347 students, enrolled in principles of economics classes during the period 1997-2001, is used to examine the relation between class attendance and student performance on examinations. Among the questions examined are: Is attendance related to performance, with and without controls for other factors? Do only substantial levels of…

Emergent features and perceptual objects: re-examining fundamental principles in analogical display design.

PubMed

Holt, Jerred; Bennett, Kevin B; Flach, John M

2015-01-01

Two sets of design principles for analogical visual displays, based on the concepts of emergent features and perceptual objects, are described. An interpretation of previous empirical findings for three displays (bar graph, polar graphic, alphanumeric) is provided from both perspectives. A fourth display (configural coordinate) was designed using principles of ecological interface design (i.e. direct perception). An experiment was conducted to evaluate performance (accuracy and latency of state identification) with these four displays. Numerous significant effects were obtained and a clear rank ordering of performance emerged (from best to worst): configural coordinate, bar graph, alphanumeric and polar graphic. These findings are consistent with principles of design based on emergent features; they are inconsistent with principles based on perceptual objects. Some limitations of the configural coordinate display are discussed and a redesign is provided. Practitioner Summary: Principles of ecological interface design, which emphasise the quality of very specific mappings between domain, display and observer constraints, are described; these principles are applicable to the design of all analogical graphical displays.

Dataflow computing approach in high-speed digital simulation

NASA Technical Reports Server (NTRS)

Ercegovac, M. D.; Karplus, W. J.

1984-01-01

New computational tools and methodologies for the digital simulation of continuous systems were explored. Programmability, and cost effective performance in multiprocessor organizations for real time simulation was investigated. Approach is based on functional style languages and data flow computing principles, which allow for the natural representation of parallelism in algorithms and provides a suitable basis for the design of cost effective high performance distributed systems. The objectives of this research are to: (1) perform comparative evaluation of several existing data flow languages and develop an experimental data flow language suitable for real time simulation using multiprocessor systems; (2) investigate the main issues that arise in the architecture and organization of data flow multiprocessors for real time simulation; and (3) develop and apply performance evaluation models in typical applications.

What Are the Principles That Guide Behaviors in the Operating Room?: Creating a Framework to Define and Measure Performance.

PubMed

Madani, Amin; Vassiliou, Melina C; Watanabe, Yusuke; Al-Halabi, Becher; Al-Rowais, Mohammed S; Deckelbaum, Dan L; Fried, Gerald M; Feldman, Liane S

2017-02-01

To identify the core principles that guide expert intraoperative behaviors and to use these principles to develop a universal framework that defines intraoperative performance. Surgical outcomes are associated with intraoperative cognitive skills. Yet, our understanding of factors that control intraoperative judgment and decision-making are limited. As a result, current methods for training and measuring performance are somewhat subjective-more task rather than procedure-oriented-and usually not standardized. They thus provide minimal insight into complex cognitive processes that are fundamental to patient safety. Cognitive task analyses for 6 diverse surgical procedures were performed using semistructured interviews and field observations to describe the thoughts, behaviors, and actions that characterize and guide expert performance. Verbal data were transcribed, supplemented with content from published literature, coded, thematically analyzed using grounded-theory by 4 independent reviewers, and synthesized into a list of items. A conceptual framework was developed based on 42 semistructured interviews lasting 45 to 120 minutes, 5 expert panels and 51 field observations involving 35 experts, and 135 sources from the literature. Five domains of intraoperative performance were identified: psychomotor skills, declarative knowledge, advanced cognitive skills, interpersonal skills, and personal resourcefulness. Within the advanced cognitive skills domain, 21 themes were perceived to guide the behaviors of surgeons: 18 for surgical planning and error prevention, and 3 for error/injury recognition, rescue, and recovery. The application of these thought patterns was highly case-specific and variable amongst subspecialties, environments, and individuals. This study provides a comprehensive definition of intraoperative expertise, with greater insight into the complex cognitive processes that seem to underlie optimal performance. This framework provides trainees and other nonexperts with the necessary information to use in deliberate practice and the creation of effective thought habits that characterize expert performance. It may help to identify gaps in performance, and to isolate root causes of surgical errors with the ultimate goal of improving patient safety.

Generalizing Landauer's principle

NASA Astrophysics Data System (ADS)

Maroney, O. J. E.

2009-03-01

In a recent paper [Stud. Hist. Philos. Mod. Phys. 36, 355 (2005)] it is argued that to properly understand the thermodynamics of Landauer’s principle it is necessary to extend the concept of logical operations to include indeterministic operations. Here we examine the thermodynamics of such operations in more detail, extending the work of Landauer to include indeterministic operations and to include logical states with variable entropies, temperatures, and mean energies. We derive the most general statement of Landauer’s principle and prove its universality, extending considerably the validity of previous proofs. This confirms conjectures made that all logical operations may, in principle, be performed in a thermodynamically reversible fashion, although logically irreversible operations would require special, practically rather difficult, conditions to do so. We demonstrate a physical process that can perform any computation without work requirements or heat exchange with the environment. Many widespread statements of Landauer’s principle are shown to be special cases of our generalized principle.

Designing Schools That Work: Organizing Resources Strategically for Student Success

ERIC Educational Resources Information Center

Miles, Karen Hawley; Ferris, Kristen

2015-01-01

This publication outlines the fundamental principles and process of Strategic School Design. Through more than a decade of research and practice in the area of school resource use, we have found that high-performing schools are responding to the changing context in education by using people, time, technology, and money in ways that look…

Strategies for Meeting High Standards: Quality Management and the Baldrige Criteria in Education. Lessons from the States.

ERIC Educational Resources Information Center

Barth, John; Burk, Zona Sharp; Serfass, Richard; Harms, Barbara Ann; Houlihan, G. Thomas; Anderson, Gerald; Farley, Raymond P.; Rigsby, Ken; O'Rourke, John

This document, one of a series of reports, focuses on the adoption of principles of quality management, originally developed by W. Edwards Deming, and the Baldrige Criteria for use in education. These processes and tools for systemic organizational management, when comprehensively applied, produce performance excellence and continuous improvement.…

High Performance Education Fails in Sustainability?--A Reflection on Finnish Primary Teacher Education

ERIC Educational Resources Information Center

Wolff, Lili-Ann; Sjöblom, Pia; Hofman-Bergholm, Maria; Palmberg, Irmeli

2017-01-01

Sustainability is internationally often emphasized as an essential aim of higher education, but more as a principle than on the practical level. This is also obvious in the academic education of primary teachers in Finland. Therefore, it is a great challenge for Finnish teachers to include sustainability in their teaching and everyday life in…

Robust Evaluation Matrix: Towards a More Principled Offline Exploration of Instructional Policies

ERIC Educational Resources Information Center

Doroudi, Shayan; Aleven, Vincent; Brunskill, Emma

2017-01-01

The gold standard for identifying more effective pedagogical approaches is to perform an experiment. Unfortunately, frequently a hypothesized alternate way of teaching does not yield an improved effect. Given the expense and logistics of each experiment, and the enormous space of potential ways to improve teaching, it would be highly preferable if…

Dynamic compression of water to 700 GPa: single- and double shock experiments on Sandia's Z machine, first principles simulations, and structure of water planets

NASA Astrophysics Data System (ADS)

Mattsson, Thomas R.

2011-11-01

Significant progress has over the last few years been made in high energy density physics (HEDP) by executing high-precision multi-Mbar experiments and performing first-principles simulations for elements ranging from carbon [1] to xenon [2]. The properties of water under HEDP conditions are of particular importance in planetary science due to the existence of ice-giants like Neptune and Uranus. Modeling the two planets, as well as water-rich exoplanets, requires knowing the equation of state (EOS), the pressure as a function of density and temperature, of water with high accuracy. Although extensive density functional theory (DFT) simulations have been performed for water under planetary conditions [3] experimental validation has been lacking. Accessing thermodynamic states along planetary isentropes in dynamic compression experiments is challenging because the principal Hugoniot follows a significantly different path in the phase diagram. In this talk, we present experimental data for dynamic compression of water up to 700 GPa, including in a regime of the phase-diagram intersected by the Neptune isentrope and water-rich models for the exoplanet GJ436b. The data was obtained on the Z-accelerator at Sandia National Laboratories by performing magnetically accelerated flyer plate impact experiments measuring both the shock and re-shock in the sample. The high accuracy makes it possible for the data to be used for detailed model validation: the results validate first principles based thermodynamics as a reliable foundation for planetary modeling and confirm the fine effect of including nuclear quantum effects on the shock pressure. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract No. DE-AC04-94AL85000. [4pt] [1] M.D. Knudson, D.H. Dolan, and M.P. Desjarlais, SCIENCE 322, 1822 (2008).[0pt] [2] S. Root, et al., Phys. Rev. Lett. 105, 085501 (2010).[0pt] [3] M. French, et al., Phys. Rev. B 79, 054107 (2009).

The balance principle in scientific research.

PubMed

Hu, Liang-ping; Bao, Xiao-lei; Wang, Qi

2012-05-01

The principles of balance, randomization, control and repetition, which are closely related, constitute the four principles of scientific research. The balance principle is the kernel of the four principles which runs through the other three. However, in scientific research, the balance principle is always overlooked. If the balance principle is not well performed, the research conclusion is easy to be denied, which may lead to the failure of the whole research. Therefore, it is essential to have a good command of the balance principle in scientific research. This article stresses the definition and function of the balance principle, the strategies and detailed measures to improve balance in scientific research, and the analysis of the common mistakes involving the use of the balance principle in scientific research.

Enroute flight planning: The design of cooperative planning systems

NASA Technical Reports Server (NTRS)

Smith, Philip J.; Layton, Chuck; Mccoy, Elaine

1990-01-01

Design concepts and principles to guide in the building of cooperative problem solving systems are being developed and evaluated. In particular, the design of cooperative systems for enroute flight planning is being studied. The investigation involves a three stage process, modeling human performance in existing environments, building cognitive artifacts, and studying the performance of people working in collaboration with these artifacts. The most significant design concepts and principles identified thus far are the principle focus.

OpenCluster: A Flexible Distributed Computing Framework for Astronomical Data Processing

NASA Astrophysics Data System (ADS)

Wei, Shoulin; Wang, Feng; Deng, Hui; Liu, Cuiyin; Dai, Wei; Liang, Bo; Mei, Ying; Shi, Congming; Liu, Yingbo; Wu, Jingping

2017-02-01

The volume of data generated by modern astronomical telescopes is extremely large and rapidly growing. However, current high-performance data processing architectures/frameworks are not well suited for astronomers because of their limitations and programming difficulties. In this paper, we therefore present OpenCluster, an open-source distributed computing framework to support rapidly developing high-performance processing pipelines of astronomical big data. We first detail the OpenCluster design principles and implementations and present the APIs facilitated by the framework. We then demonstrate a case in which OpenCluster is used to resolve complex data processing problems for developing a pipeline for the Mingantu Ultrawide Spectral Radioheliograph. Finally, we present our OpenCluster performance evaluation. Overall, OpenCluster provides not only high fault tolerance and simple programming interfaces, but also a flexible means of scaling up the number of interacting entities. OpenCluster thereby provides an easily integrated distributed computing framework for quickly developing a high-performance data processing system of astronomical telescopes and for significantly reducing software development expenses.

The Cardiovascular Physiology of Sports and Exercise.

PubMed

Opondo, Mildred A; Sarma, Satyam; Levine, Benjamin D

2015-07-01

Athletes represent the extremes of human performance. Many of their remarkable abilities stem from a cardiovascular system that has adapted to meet the metabolic needs of exercising muscle. A large and compliant heart is a hallmark feature of athletes who engage in highly aerobic events. Despite high fitness levels, athletes may present with symptoms that limit performance. Understanding and dissecting these limitations requires a strong background in sports science and the factors that determine sports capabilities. This article reviews the basic principles of exercise physiology, cardiovascular adaptations unique to the "athlete's heart," and the utility of exercise testing in athletes. Copyright © 2015 Elsevier Inc. All rights reserved.

Novel optical gyroscope: proof of principle demonstration and future scope

PubMed Central

Srivastava, Shailesh; Rao D. S., Shreesha; Nandakumar, Hari

2016-01-01

We report the first proof-of-principle demonstration of the resonant optical gyroscope with reflector that we have recently proposed. The device is very different from traditional optical gyroscopes since it uses the inherent coupling between the clockwise and counterclockwise propagating waves to sense the rotation. Our demonstration confirms our theoretical analysis and simulations. We also demonstrate a novel method of biasing the gyroscope using orthogonal polarization states. The simplicity of the structure and the readout method, the theoretically predicted high sensitivities (better than 0.001 deg/hr), and the possibility of further performance enhancement using a related laser based active device, all have immense potential for attracting fresh research and technological initiatives. PMID:27694987

Mechanism-Based Design for High-Temperature, High-Performance Composites. Book 2

DTIC Science & Technology

1997-09-01

Sei. Eng. 1994, A188, 107 2 Lu, T.J. and Hutchinson, J.W. /. Am. Ceram. Soc. 1995,78, 261 3 Carlsson, L.A., Gillespie, J.W. and Pipes , R.B. J. Compos...Douglas Technologies Inc. (MDTI). It has potential commercial applications in jet engine exhaust ducts, leading edges, nose cones, and other hot...measured using the Archimedes principle in deionized water. Specimens were ground, polished, and ther- mally etched to reveal grain boundaries

Exploiting Anti-T-shaped Graphene Architecture to Form Low Tortuosity, Sieve-like Interfaces for High-Performance Anodes for Li-Based Cells

PubMed Central

2017-01-01

Graphitic carbon anodes have long been used in Li ion batteries due to their combination of attractive properties, such as low cost, high gravimetric energy density, and good rate capability. However, one significant challenge is controlling, and optimizing, the nature and formation of the solid electrolyte interphase (SEI). Here it is demonstrated that carbon coating via chemical vapor deposition (CVD) facilitates high electrochemical performance of carbon anodes. We examine and characterize the substrate/vertical graphene interface (multilayer graphene nanowalls coated onto carbon paper via plasma enhanced CVD), revealing that these low-tortuosity and high-selection graphene nanowalls act as fast Li ion transport channels. Moreover, we determine that the hitherto neglected parallel layer acts as a protective surface at the interface, enhancing the anode performance. In summary, these findings not only clarify the synergistic role of the parallel functional interface when combined with vertical graphene nanowalls but also have facilitated the development of design principles for future high rate, high performance batteries. PMID:29392179

Guidelines for application of fluorescent lamps in high-performance avionic backlight systems

NASA Astrophysics Data System (ADS)

Syroid, Daniel D.

1997-07-01

Fluorescent lamps have proven to be well suited for use in high performance avionic backlight systems as demonstrated by numerous production applications for both commercial and military cockpit displays. Cockpit display applications include: Boeing 777, new 737s, F-15, F-16, F-18, F-22, C- 130, Navy P3, NASA Space Shuttle and many others. Fluorescent lamp based backlights provide high luminance, high lumen efficiency, precision chromaticity and long life for avionic active matrix liquid crystal display applications. Lamps have been produced in many sizes and shapes. Lamp diameters range from 2.6 mm to over 20 mm and lengths for the larger diameter lamps range to over one meter. Highly convoluted serpentine lamp configurations are common as are both hot and cold cathode electrode designs. This paper will review fluorescent lamp operating principles, discuss typical requirements for avionic grade lamps, compare avionic and laptop backlight designs and provide guidelines for the proper application of lamps and performance choices that must be made to attain optimum system performance considering high luminance output, system efficiency, dimming range and cost.

High-Resolution “Fleezers”: Dual-Trap Optical Tweezers Combined with Single-Molecule Fluorescence Detection

PubMed Central

Whitley, Kevin D.; Comstock, Matthew J.; Chemla, Yann R.

2017-01-01

Recent advances in optical tweezers have greatly expanded their measurement capabilities. A new generation of hybrid instrument that combines nanomechanical manipulation with fluorescence detection—fluorescence optical tweezers, or “fleezers”—is providing a powerful approach to study complex macromolecular dynamics. Here, we describe a combined high-resolution optical trap/confocal fluorescence microscope that can simultaneously detect sub-nanometer displacements, sub-piconewton forces, and single-molecule fluorescence signals. The primary technical challenge to these hybrid instruments is how to combine both measurement modalities without sacrificing the sensitivity of either one. We present general design principles to overcome this challenge and provide detailed, step-by-step instructions to implement them in the construction and alignment of the instrument. Lastly, we present a set of protocols to perform a simple, proof-of-principle experiment that highlights the instrument capabilities. PMID:27844430

A study of the high-precision displacement laser probe

NASA Astrophysics Data System (ADS)

Fan, Yuming; Zhang, Guoxiong

2006-06-01

On the basis of the measuring principle of the dynamic active optical confocal probe based on time difference measurement that has a reference path, a dynamic active optical confocal probe based on time difference measurement but has no reference path is developed. In this paper, the working principle of this optical confocal probe is dissertated. A large-scale integrated measuring system is designed to simplify the structure of the probe and to enhance the stability of the probe. Single-chip microcomputer system with a high-speed ADC is selected in the measurement and control system of the probe. At the end of the paper, experiments on the performance of the optical confocal probe based on time difference measurement with no reference path are carried out. Experiment results show that the probe has a measuring resolution of 0.05μm, a measuring range of 0.2mm and a linearity of 0.4μm.

New Research on MEMS Acoustic Vector Sensors Used in Pipeline Ground Markers

PubMed Central

Song, Xiaopeng; Jian, Zeming; Zhang, Guojun; Liu, Mengran; Guo, Nan; Zhang, Wendong

2015-01-01

According to the demands of current pipeline detection systems, the above-ground marker (AGM) system based on sound detection principle has been a major development trend in pipeline technology. A novel MEMS acoustic vector sensor for AGM systems which has advantages of high sensitivity, high signal-to-noise ratio (SNR), and good low frequency performance has been put forward. Firstly, it is presented that the frequency of the detected sound signal is concentrated in a lower frequency range, and the sound attenuation is relatively low in soil. Secondly, the MEMS acoustic vector sensor structure and basic principles are introduced. Finally, experimental tests are conducted and the results show that in the range of 0°∼90°, when r = 5 m, the proposed MEMS acoustic vector sensor can effectively detect sound signals in soil. The measurement errors of all angles are less than 5°. PMID:25609046

Student Performance in Undergraduate Economics Courses

ERIC Educational Resources Information Center

Mumford, Kevin J.; Ohland, Matthew W.

2011-01-01

Using undergraduate student records from six large public universities from 1990 to 2003, the authors analyze the characteristics and performance of students by major in two economics courses: Principles of Microeconomics and Intermediate Microeconomics. This article documents important differences across students by major in the principles course…

Next level of board accountability in health care quality.

PubMed

Pronovost, Peter J; Armstrong, C Michael; Demski, Renee; Peterson, Ronald R; Rothman, Paul B

2018-03-19

Purpose The purpose of this paper is to offer six principles that health system leaders can apply to establish a governance and management system for the quality of care and patient safety. Design/methodology/approach Leaders of a large academic health system set a goal of high reliability and formed a quality board committee in 2011 to oversee quality and patient safety everywhere care was delivered. Leaders of the health system and every entity, including inpatient hospitals, home care companies, and ambulatory services staff the committee. The committee works with the management for each entity to set and achieve quality goals. Through this work, the six principles emerged to address management structures and processes. Findings The principles are: ensure there is oversight for quality everywhere care is delivered under the health system; create a framework to organize and report the work; identify care areas where quality is ambiguous or underdeveloped (i.e. islands of quality) and work to ensure there is reporting and accountability for quality measures; create a consolidated quality statement similar to a financial statement; ensure the integrity of the data used to measure and report quality and safety performance; and transparently report performance and create an explicit accountability model. Originality/value This governance and management system for quality and safety functions similar to a finance system, with quality performance documented and reported, data integrity monitored, and accountability for performance from board to bedside. To the authors' knowledge, this is the first description of how a board has taken this type of systematic approach to oversee the quality of care.

Design and research on discharge performance for aluminum-air battery

NASA Astrophysics Data System (ADS)

Liu, Zu; Zhao, Junhong; Cai, Yanping; Xu, Bin

2017-01-01

As a kind of clean energy, the research of aluminum air battery is carried out because aluminum-air battery has advantages of high specific energy, silence and low infrared. Based on the research on operating principle of aluminum-air battery, a novel aluminum-air battery system was designed composed of aluminum-air cell and the circulation system of electrolyte. A system model is established to analyze the polarization curve, the constant current discharge performance and effect of electrolyte concentration on the performance of monomer. The experimental results show that the new energy aluminum-air battery has good discharge performance, which lays a foundation for its application.

High-efficiency non-blocking phosphorescent organic light emitting diode with ultrathin emission layer

NASA Astrophysics Data System (ADS)

Qiu, Jacky; Helander, Michael G.; Wang, Zhibin; Chang, Yi-Lu; Lu, ZhengHong

2012-09-01

Non-blocking Phosphorescent Organic Light Emitting Diode (NB-PHOLED) is a highly simplified device structure that has achieved record high device performance on chlorinated ITO[1], flexible substrates[2], also with Pt based phosphorescent dopants[3] and NB-PHOLED has significantly reduced efficiency roll-off[4]. The principle novel features of NB-PHOLED is the absence of blocking layer in the OLED stack, as well as the absence of organic hole injection layer, this allows for reduction of carrier accumulation in between organic layers and result in higher efficiencies.

Local electronic effects and irradiation resistance in high-entropy alloys

DOE PAGES

Egami, Takeshi; Stocks, George Malcolm; Nicholson, Don; ...

2015-08-14

High-entropy alloys are multicomponent solid solutions in which various elements with different chemistries and sizes occupy the same crystallographic lattice sites. Thus, none of the atoms perfectly fit the lattice site, giving rise to considerable local lattice distortions and atomic-level stresses. These characteristics can be beneficial for performance under both radiation and in a high-temperature environment, making them attractive candidates as nuclear materials. We discuss electronic origin of the atomic-level stresses based upon first-principles calculations using a density functional theory approach.

High Q-factor metasurfaces based on miniaturized asymmetric single split resonators

NASA Astrophysics Data System (ADS)

Al-Naib, Ibraheem A. I.; Jansen, Christian; Koch, Martin

2009-04-01

We introduce asymmetric single split rectangular resonators as bandstop metasurfaces, which exhibit very high Q-factors in combination with low passband losses and a small electrical footprint. The effect of the degree of asymmetry on the frequency response is thoroughly studied. Furthermore, complementary structures, which feature a bandpass behavior, were derived by applying Babinet's principle and investigated with regards to their transmission characteristics. In future, asymmetric single split rectangular resonators could provide efficient unit cells for frequency selective surface devices, such as thin-film sensors or high performance filters.

Enhanced photocatalytic performance of KNbO3(100)/reduced graphene oxide nanocomposites investigated using first-principles calculations: RGO reductivity effect

NASA Astrophysics Data System (ADS)

Zhang, Pan; Shen, Yanqing; Wu, Wenjing; Li, Jun; Zhou, Zhongxiang

2018-03-01

Although a number of various reduced graphene oxide (RGO)-based nanomaterials with enhanced photocatalytic performance have recently been characterized, the effect of RGO reductivity on their performance is still not clear. Herein, KNbO3(100) surface modification with three RGO sheets of different reductivity is investigated using first-principles calculations, revealing that increasing RGO reductivity enhances the photocatalytic performance of KNbO3(100)/RGO nanocomposites. In contrast to CeO2/RGO nanocomposites, the O atoms of RGO inhibit the photoactivity of KNbO3/RGO nanocomposites by restraining the effect of inducing a red shift of the corresponding photocatalytic absorption spectra by C 2p states. Increased RGO reductivity extends its absorption edge to the visible light region of the optical absorption and also promotes charge transfer from the KNbO3(100) surface to RGO sheets, in contrast to the behavior observed for g-C3N4/RGO composites. Overall, this work provides a reasonable explanation of controversial experimental results obtained previously, paving the way to the development of highly efficient RGO-based photocatalysts and promoting further photocatalytic applications of KNbO3/RGO nanocomposites.

How "moral" are the principles of biomedical ethics?--a cross-domain evaluation of the common morality hypothesis.

PubMed

Christen, Markus; Ineichen, Christian; Tanner, Carmen

2014-06-17

The principles of biomedical ethics - autonomy, non-maleficence, beneficence, and justice - are of paradigmatic importance for framing ethical problems in medicine and for teaching ethics to medical students and professionals. In order to underline this significance, Tom L. Beauchamp and James F. Childress base the principles in the common morality, i.e. they claim that the principles represent basic moral values shared by all persons committed to morality and are thus grounded in human moral psychology. We empirically investigated the relationship of the principles to other moral and non-moral values that provide orientations in medicine. By way of comparison, we performed a similar analysis for the business & finance domain. We evaluated the perceived degree of "morality" of 14 values relevant to medicine (n1 = 317, students and professionals) and 14 values relevant to business & finance (n2 = 247, students and professionals). Ratings were made along four dimensions intended to characterize different aspects of morality. We found that compared to other values, the principles-related values received lower ratings across several dimensions that characterize morality. By interpreting our finding using a clustering and a network analysis approach, we suggest that the principles can be understood as "bridge values" that are connected both to moral and non-moral aspects of ethical dilemmas in medicine. We also found that the social domain (medicine vs. business & finance) influences the degree of perceived morality of values. Our results are in conflict with the common morality hypothesis of Beauchamp and Childress, which would imply domain-independent high morality ratings of the principles. Our findings support the suggestions by other scholars that the principles of biomedical ethics serve primarily as instruments in deliberated justifications, but lack grounding in a universal "common morality". We propose that the specific manner in which the principles are taught and discussed in medicine - namely by referring to conflicts requiring a balancing of principles - may partly explain why the degree of perceived "morality" of the principles is lower compared to other moral values.

How “moral” are the principles of biomedical ethics? – a cross-domain evaluation of the common morality hypothesis

PubMed Central

2014-01-01

Background The principles of biomedical ethics – autonomy, non-maleficence, beneficence, and justice – are of paradigmatic importance for framing ethical problems in medicine and for teaching ethics to medical students and professionals. In order to underline this significance, Tom L. Beauchamp and James F. Childress base the principles in the common morality, i.e. they claim that the principles represent basic moral values shared by all persons committed to morality and are thus grounded in human moral psychology. We empirically investigated the relationship of the principles to other moral and non-moral values that provide orientations in medicine. By way of comparison, we performed a similar analysis for the business & finance domain. Methods We evaluated the perceived degree of “morality” of 14 values relevant to medicine (n1 = 317, students and professionals) and 14 values relevant to business & finance (n2 = 247, students and professionals). Ratings were made along four dimensions intended to characterize different aspects of morality. Results We found that compared to other values, the principles-related values received lower ratings across several dimensions that characterize morality. By interpreting our finding using a clustering and a network analysis approach, we suggest that the principles can be understood as “bridge values” that are connected both to moral and non-moral aspects of ethical dilemmas in medicine. We also found that the social domain (medicine vs. business & finance) influences the degree of perceived morality of values. Conclusions Our results are in conflict with the common morality hypothesis of Beauchamp and Childress, which would imply domain-independent high morality ratings of the principles. Our findings support the suggestions by other scholars that the principles of biomedical ethics serve primarily as instruments in deliberated justifications, but lack grounding in a universal “common morality”. We propose that the specific manner in which the principles are taught and discussed in medicine – namely by referring to conflicts requiring a balancing of principles – may partly explain why the degree of perceived “morality” of the principles is lower compared to other moral values. PMID:24938295

The influence and analysis of natural crosswind on cooling characteristics of the high level water collecting natural draft wet cooling tower

NASA Astrophysics Data System (ADS)

Ma, Libin; Ren, Jianxing

2018-01-01

Large capacity and super large capacity thermal power is becoming the main force of energy and power industry in our country. The performance of cooling tower is related to the water temperature of circulating water, which has an important influence on the efficiency of power plant. The natural draft counter flow wet cooling tower is the most widely used cooling tower type at present, and the high cooling tower is a new cooling tower based on the natural ventilation counter flow wet cooling tower. In this paper, for high cooling tower, the application background of high cooling tower is briefly explained, and then the structure principle of conventional cooling tower and high cooling tower are introduced, and the difference between them is simply compared. Then, the influence of crosswind on cooling performance of high cooling tower under different wind speeds is introduced in detail. Through analysis and research, wind speed, wind cooling had little impact on the performance of high cooling tower; wind velocity, wind will destroy the tower inside and outside air flow, reducing the cooling performance of high cooling tower; Wind speed, high cooling performance of cooling tower has increased, but still lower than the wind speed.

Improving Schools through Collaboration: A Mixed Methods Study of School-to-School Partnerships in the Primary Sector

ERIC Educational Resources Information Center

Muijs, Daniel

2015-01-01

The principle of schools collaborating to improve is one that has seen growing interest in recent years, and there is emerging evidence that in particular collaboration between high and lower performing schools can be an effective school improvement method. However, this evidence relates primarily to secondary schools, and little research has been…

Getting down to Dollars and Cents: What Do School Districts Spend to Deliver Student-Centered Learning?

ERIC Educational Resources Information Center

Miller, Lawrence J.; Gross, Betheny; Ouijdani, Monica

2012-01-01

In the era of No Child Left Behind and Race to the Top, school districts are under increasing pressure from policymakers to hold all students to high performance standards. In response, a growing number of schools are embracing the principles of student-centered learning (SCL). SCL is a contemporary approach that combines progressive and…

Simple-Minded Accountability Measures Create Failing Schools in Disadvantaged Contexts: A Case Study of a Swedish Junior High School

ERIC Educational Resources Information Center

Allodi, Mara Westling

2013-01-01

The principles of new public management -- market mechanisms, accountability and standards -- have been applied in the education system. These methods are supposed to increase efficiency, but there is also a risk of negative consequences from the services provided if the measures of performance target a reduced range of goals, ignore relevant…

Towards the Solution of Abysmal Performance in Mathematics in Junior High Schools: Comparing the Pedagogical Potential of Two Designed Interventions

ERIC Educational Resources Information Center

Sarfo, Frederick Kwaku; Eshun, Grace; Elen, Jan; Adentwi, Kobina Impraim

2014-01-01

Introduction: In this study, the effectiveness of two different interventions was investigated. The effects of a concrete abstract intervention and a regular method of teaching intervention were compared. Both interventions were designed in line with the specifications of classical principles of instructional design for learning mathematics in the…

Replacing critical rare earth materials in high energy density magnets

NASA Astrophysics Data System (ADS)

McCallum, R. William

2012-02-01

High energy density permanent magnets are crucial to the design of internal permanent magnet motors (IPM) for hybride and electric vehicles and direct drive wind generators. Current motor designs use rare earth permanent magnets which easily meet the performance goals, however, the rising concerns over cost and foreign control of the current supply of rare earth resources has motivated a search for non-rare earth based permanent magnets alloys with performance metrics which allow the design of permanent magnet motors and generators without rare earth magnets. This talk will discuss the state of non-rare-earth permanent magnets and efforts to both improve the current materials and find new materials. These efforts combine first principles calculations and meso-scale magnetic modeling with advance characterization and synthesis techniques in order to advance the state of the art in non rare earth permanent magnets. The use of genetic algorithms in first principle structural calculations, combinatorial synthesis in the experimental search for materials, atom probe microscopy to characterize grain boundaries on the atomic level, and other state of the art techniques will be discussed. In addition the possibility of replacing critical rare earth elements with the most abundant rare earth Ce will be discussed.

Towards Testing General Relativity with a dual species interferometer

NASA Astrophysics Data System (ADS)

Schlippert, Dennis; Hartwig, Jonas; Tiarks, Daniel; Velte, Ulrich; Ganske, Sven; Ertmer, Wolfgang; Rasel, Ernst M.

2012-06-01

We report on our work directed towards a dual species matter-wave interferometer for performing a differential measurement of the acceleration of free falling ^87Rb and ^39K atoms to test Einstein's equivalence principle (universality of free fall). Based on minimal Standard Model Extension calculations this combination of test masses is more sensitive to composition based equivalence principle violating effects than, e.g. ^85Rb-^87Rb. During free fall, a Mach-Zehnder type interferometry sequence employing stimulated Raman transitions is applied synchronously for both species, achieving high common noise rejection. With an expected single shot resolution of 5x10-8g the apparatus will allow for studying systematics at the 10-9g level after 100 s integration time. Post-correction methods for high vibrational noise environments are investigated. To assure well defined starting conditions the two species will be trapped in an optical dipole trap. The properties of this trap at 2 μm allow for fast and efficient laser cooling, use of evaporative and sympathetic cooling techniques is possible. We will show the enviromental noise limited performance of the single species Rb gravimeter and the progress of the implementation of the K gravimeter.

Research on simulation system with the wide range and high-precision laser energy characteristics

NASA Astrophysics Data System (ADS)

Dong, Ke-yan; Lou, Yan; He, Jing-yi; Tong, Shou-feng; Jiang, Hui-lin

2012-10-01

The Hardware-in-the-loop(HWIL) simulation test is one of the important parts for the development and performance testing of semi-active laser-guided weapons. In order to obtain accurate results, the confidence level of the target environment should be provided for a high-seeker during the HWIL simulation test of semi-active laser-guided weapons, and one of the important simulation parameters is the laser energy characteristic. In this paper, based on the semi-active laser-guided weapon guidance principles, an important parameter of simulation of confidence which affects energy characteristics in performance test of HWIL simulation was analyzed. According to the principle of receiving the same energy by using HWIL simulation and in practical application, HWIL energy characteristics simulation systems with the crystal absorption structure was designed. And on this basis, the problems of optimal design of the optical system were also analyzed. The measured results show that the dynamic attenuation range of the system energy is greater than 50dB, the dynamic attenuation stability is less than 5%, and the maximum energy changing rate driven by the servo motor is greater than 20dB/s.

Laser based in-situ and standoff detection of chemical warfare agents and explosives

NASA Astrophysics Data System (ADS)

Patel, C. Kumar N.

2009-09-01

Laser based detection of gaseous, liquid and solid residues and trace amounts has been developed ever since lasers were invented. However, the lack of availability of reasonably high power tunable lasers in the spectral regions where the relevant targets can be interrogated as well as appropriate techniques for high sensitivity, high selectivity detection has hampered the practical exploitation of techniques for the detection of targets important for homeland security and defense applications. Furthermore, emphasis has been on selectivity without particular attention being paid to the impact of interfering species on the quality of detection. Having high sensitivity is necessary but not a sufficient condition. High sensitivity assures a high probability of detection of the target species. However, it is only recently that the sensor community has come to recognize that any measure of probability of detection must be associated with a probability of false alarm, if it is to have any value as a measure of performance. This is especially true when one attempts to compare performance characteristics of different sensors based on different physical principles. In this paper, I will provide a methodology for characterizing the performance of sensors utilizing optical absorption measurement techniques. However, the underlying principles are equally application to all other sensors. While most of the current progress in high sensitivity, high selectivity detection of CWAs, TICs and explosives involve identifying and quantifying the target species in-situ, there is an urgent need for standoff detection of explosives from safe distances. I will describe our results on CO2 and quantum cascade laser (QCL) based photoacoustic sensors for the detection of CWAs, TICs and explosives as well the very new results on stand-off detection of explosives at distances up to 150 meters. The latter results are critically important for assuring safety of military personnel in battlefield environment, especially from improvised explosive devices (IEDs), and of civilian personnel from terrorist attacks in metropolitan areas.

Harnessing the concurrent reaction dynamics in active Si and Ge to achieve high performance lithium-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Qiaobao; Chen, Huixin; Luo, Langli

Advanced composite electrodes containing multiple active components are often used in lithium-ion batteries for practical applications. The performance of such heterogeneous composite electrodes can in principle be enhanced by tailoring the concurrent reaction dynamics in multiple active components for promoting their collective beneficial effects. However, the potential of this design principle has remained uncharted to date. Here we develop a composite anode of Cu/Si/Ge nanowire arrays, where each nanowire consists of a core of Cu segments and a Si/Ge bilayer shell. This unique electrode architecture exhibited a markedly improved electrochemical performance over the reference Cu/Si systems, demonstrating a stable capacitymore » retention (81% after 3000 cycles at 2C) and doubled specific capacity at a rate of 16C (1C = 2 A g1). By using in situ transmission electron microscopy and electrochemical testing, we unravel a novel reaction mechanism of dynamic co-lithiation/co-delithiation in the active Si and Ge bilayer, which is shown to effectively alleviate the electrochemically induced mechanical degradation and thus greatly enhance the long-cycle stability of the electrode. Our findings offer insights into a rational design of high-performance lithium-ion batteries via exploiting the concurrent reaction dynamics in the multiple active components of composite electrodes.A composite anode of Cu/Si/Ge nanowire arrays grown on a porous Ni foam enables the outstanding capacity, rate capability and cycle stability of Li-ion batteries.« less

Approximate similarity principle for a full-scale STOVL ejector

NASA Astrophysics Data System (ADS)

Barankiewicz, Wendy S.; Perusek, Gail P.; Ibrahim, Mounir B.

1994-03-01

Full-scale ejector experiments are expensive and difficult to implement at engine exhaust temperatures. For this reason the utility of using similarity principles, in particular the Munk and prim principle for isentropic flow, was explored. Static performance test data for a full-scale thrust augmenting ejector were analyzed for primary flow temperature up to 1560 R. At different primary temperatures, exit pressure contours were compared for similarity. A nondimensional flow parameter is then used to eliminate primary nozzle temperature dependence and verify similarity between the hot and cold flow experiments. Under the assumption that an appropriate similarity principle can be established, properly chosen performance parameters were found to be similar for both flow and cold flow model tests.

Can We Train Machine Learning Methods to Outperform the High-dimensional Propensity Score Algorithm?

PubMed

Karim, Mohammad Ehsanul; Pang, Menglan; Platt, Robert W

2018-03-01

The use of retrospective health care claims datasets is frequently criticized for the lack of complete information on potential confounders. Utilizing patient's health status-related information from claims datasets as surrogates or proxies for mismeasured and unobserved confounders, the high-dimensional propensity score algorithm enables us to reduce bias. Using a previously published cohort study of postmyocardial infarction statin use (1998-2012), we compare the performance of the algorithm with a number of popular machine learning approaches for confounder selection in high-dimensional covariate spaces: random forest, least absolute shrinkage and selection operator, and elastic net. Our results suggest that, when the data analysis is done with epidemiologic principles in mind, machine learning methods perform as well as the high-dimensional propensity score algorithm. Using a plasmode framework that mimicked the empirical data, we also showed that a hybrid of machine learning and high-dimensional propensity score algorithms generally perform slightly better than both in terms of mean squared error, when a bias-based analysis is used.

Using Crickets to Introduce Neurophysiology to Early Undergraduate Students

PubMed Central

Dagda, Ruben K.; Thalhauser, Rachael M.; Dagda, Raul; Marzullo, Timothy C.; Gage, Gregory J.

2013-01-01

Anatomy and physiology instructors often face the daunting task of teaching the principles of neurophysiology as part of a laboratory course with very limited resources. Teaching neurophysiology can be a difficult undertaking as sophisticated electrophysiology and data acquisition equipment is often financially out-of-reach for two-year institutions, and for many preparations, instructors need to be highly skilled in electrophysiology techniques when teaching hands-on laboratories. In the absence of appropriate laboratory tools, many undergraduate students have difficulty understanding concepts related to neurophysiology. The cricket can serve as a reliable invertebrate model to teach the basic concepts of neurophysiology in the educational laboratory. In this manuscript, we describe a series of hands-on, demonstrative, technologically simple, and affordable laboratory activities that will help undergraduate students gain an understanding of the principles of neurophysiology. By using the cerci ganglion and leg preparation, students can quantify extracellular neural activity in response to sensory stimulation, understand the principles of rate coding and somatotopy, perform electrical microstimulation to understand the threshold of sensory stimulation, and do pharmacological manipulation of neuronal activity. We describe the utility of these laboratory activities, provide a convenient protocol for quantifying extracellular recordings, and discuss feedback provided by undergraduate students with regards to the quality of the educational experience after performing the lab activities. PMID:24319394

High-Performance Java Codes for Computational Fluid Dynamics

NASA Technical Reports Server (NTRS)

Riley, Christopher; Chatterjee, Siddhartha; Biswas, Rupak; Biegel, Bryan (Technical Monitor)

2001-01-01

The computational science community is reluctant to write large-scale computationally -intensive applications in Java due to concerns over Java's poor performance, despite the claimed software engineering advantages of its object-oriented features. Naive Java implementations of numerical algorithms can perform poorly compared to corresponding Fortran or C implementations. To achieve high performance, Java applications must be designed with good performance as a primary goal. This paper presents the object-oriented design and implementation of two real-world applications from the field of Computational Fluid Dynamics (CFD): a finite-volume fluid flow solver (LAURA, from NASA Langley Research Center), and an unstructured mesh adaptation algorithm (2D_TAG, from NASA Ames Research Center). This work builds on our previous experience with the design of high-performance numerical libraries in Java. We examine the performance of the applications using the currently available Java infrastructure and show that the Java version of the flow solver LAURA performs almost within a factor of 2 of the original procedural version. Our Java version of the mesh adaptation algorithm 2D_TAG performs within a factor of 1.5 of its original procedural version on certain platforms. Our results demonstrate that object-oriented software design principles are not necessarily inimical to high performance.

GUIDING PRINCIPLES FOR GOOD PRACTICES IN HOSPITAL-BASED HEALTH TECHNOLOGY ASSESSMENT UNITS.

PubMed

Sampietro-Colom, Laura; Lach, Krzysztof; Pasternack, Iris; Wasserfallen, Jean-Blaise; Cicchetti, Americo; Marchetti, Marco; Kidholm, Kristian; Arentz-Hansen, Helene; Rosenmöller, Magdalene; Wild, Claudia; Kahveci, Rabia; Ulst, Margus

2015-01-01

Health technology assessment (HTA) carried out for policy decision making has well-established principles unlike hospital-based HTA (HB-HTA), which differs from the former in the context characteristics and ways of operation. This study proposes principles for good practices in HB-HTA units. A framework for good practice criteria was built inspired by the EFQM excellence business model and information from six literature reviews, 107 face-to-face interviews, forty case studies, large-scale survey, focus group, Delphi survey, as well as local and international validation. In total, 385 people from twenty countries have participated in defining the principles for good practices in HB-HTA units. Fifteen guiding principles for good practices in HB-HTA units are grouped in four dimensions. Dimension 1 deals with principles of the assessment process aimed at providing contextualized information for hospital decision makers. Dimension 2 describes leadership, strategy and partnerships of HB-HTA units which govern and facilitate the assessment process. Dimension 3 focuses on adequate resources that ensure the operation of HB-HTA units. Dimension 4 deals with measuring the short- and long-term impact of the overall performance of HB-HTA units. Finally, nine core guiding principles were selected as essential requirements for HB-HTA units based on the expertise of the HB-HTA units participating in the project. Guiding principles for good practices set up a benchmark for HB-HTA because they represent the ideal performance of HB-HTA units; nevertheless, when performing HTA at hospital level, context also matters; therefore, they should be adapted to ensure their applicability in the local context.

The Impact on Student Achievement Following Professional Development on the Principles of Formative Assessment

ERIC Educational Resources Information Center

DeNome, Evonne C.

2015-01-01

This quantitative study reviews the impact on student achievement following professional development on the principles of formative assessment. The study compared mathematics and reading performance data from student populations with teachers who received training in formative assessment to performance data from student populations with teachers…

Combining first-principles and data modeling for the accurate prediction of the refractive index of organic polymers

NASA Astrophysics Data System (ADS)

Afzal, Mohammad Atif Faiz; Cheng, Chong; Hachmann, Johannes

2018-06-01

Organic materials with a high index of refraction (RI) are attracting considerable interest due to their potential application in optic and optoelectronic devices. However, most of these applications require an RI value of 1.7 or larger, while typical carbon-based polymers only exhibit values in the range of 1.3-1.5. This paper introduces an efficient computational protocol for the accurate prediction of RI values in polymers to facilitate in silico studies that can guide the discovery and design of next-generation high-RI materials. Our protocol is based on the Lorentz-Lorenz equation and is parametrized by the polarizability and number density values of a given candidate compound. In the proposed scheme, we compute the former using first-principles electronic structure theory and the latter using an approximation based on van der Waals volumes. The critical parameter in the number density approximation is the packing fraction of the bulk polymer, for which we have devised a machine learning model. We demonstrate the performance of the proposed RI protocol by testing its predictions against the experimentally known RI values of 112 optical polymers. Our approach to combine first-principles and data modeling emerges as both a successful and a highly economical path to determining the RI values for a wide range of organic polymers.

Origin of Outstanding Stability in the Lithium Solid Electrolyte Materials: Insights from Thermodynamic Analyses Based on First-Principles Calculations

DOE PAGES

Zhu, Yizhou; He, Xingfeng; Mo, Yifei

2015-10-06

First-principles calculations were performed to investigate the electrochemical stability of lithium solid electrolyte materials in all-solid-state Li-ion batteries. The common solid electrolytes were found to have a limited electrochemical window. Our results suggest that the outstanding stability of the solid electrolyte materials is not thermodynamically intrinsic but is originated from kinetic stabilizations. The sluggish kinetics of the decomposition reactions cause a high overpotential leading to a nominally wide electrochemical window observed in many experiments. The decomposition products, similar to the solid-electrolyte-interphases, mitigate the extreme chemical potential from the electrodes and protect the solid electrolyte from further decompositions. With the aidmore » of the first-principles calculations, we revealed the passivation mechanism of these decomposition interphases and quantified the extensions of the electrochemical window from the interphases. We also found that the artificial coating layers applied at the solid electrolyte and electrode interfaces have a similar effect of passivating the solid electrolyte. Our newly gained understanding provided general principles for developing solid electrolyte materials with enhanced stability and for engineering interfaces in all-solid-state Li-ion batteries.« less

Quality control of the paracetamol drug by chemometrics and imaging spectroscopy in the near infrared region

NASA Astrophysics Data System (ADS)

Baptistao, Mariana; Rocha, Werickson Fortunato de Carvalho; Poppi, Ronei Jesus

2011-09-01

In this work, it was used imaging spectroscopy and chemometric tools for the development and analysis of paracetamol and excipients in pharmaceutical formulations. It was also built concentration maps to study the distribution of the drug in the tablets surface. Multivariate models based on PLS regression were developed for paracetamol and excipients concentrations prediction. For the construction of the models it was used 31 samples in the tablet form containing the active principle in a concentration range of 30.0-90.0% (w/w) and errors below to 5% were obtained for validation samples. Finally, the study of the distribution in the drug was performed through the distribution maps of concentration of active principle and excipients. The analysis of maps showed the complementarity between the active principle and excipients in the tablets. The region with a high concentration of a constituent must have, necessarily, absence or low concentration of the other one. Thus, an alternative method for the paracetamol drug quality monitoring is presented.

Natural Treatment Systems as Sustainable Ecotechnologies for the Developing Countries

PubMed Central

Mahmood, Qaisar; Pervez, Arshid; Zeb, Bibi Saima; Zaffar, Habiba; Yaqoob, Hajra; Waseem, Muhammad; Zahidullah

2013-01-01

The purpose of natural treatment systems is the re-establishment of disturbed ecosystems and their sustainability for benefits to human and nature. The working of natural treatment systems on ecological principles and their sustainability in terms of low cost, low energy consumption, and low mechanical technology is highly desirable. The current review presents pros and cons of the natural treatment systems, their performance, and recent developments to use them in the treatment of various types of wastewaters. Fast population growth and economic pressure in some developing countries compel the implementation of principles of natural treatment to protect natural environment. The employment of these principles for waste treatment not only helps in environmental cleanup but also conserves biological communities. The systems particularly suit developing countries of the world. We reviewed information on constructed wetlands, vermicomposting, role of mangroves, land treatment systems, soil-aquifer treatment, and finally aquatic systems for waste treatment. Economic cost and energy requirements to operate various kinds of natural treatment systems were also reviewed. PMID:23878819

High-performance DIRC detector for the future Electron Ion Collider experiment

NASA Astrophysics Data System (ADS)

Kalicy, G.; Allison, L.; Cao, T.; Dzhygadlo, R.; Hartlove, T.; Horn, T.; Hyde, C.; Ilieva, Y.; Nadel-Turonski, P.; Park, K.; Peters, K.; Schwarz, C.; Schwiening, J.; Stevens, J.; Xi, W.; Zorn, C.

2018-04-01

Excellent particle identification (PID) is an essential requirement for a future Electron-Ion Collider (EIC) detector. Identification of the hadrons in the final state is critical to study how different quark flavors contribute to nucleon properties. A detector based on the Detection of Internally Reflected Cherenkov light (DIRC) principle, with a radial size of only a few cm, is a perfect solution for those requirements. The R&D process performed by the EIC PID consortium (eRD14) is focused on designing a high-performance DIRC that would extend the momentum coverage well beyond the state-of-the-art, allowing 3 standard deviations or more separation of π/K up to 6 GeV/c, e/π up to 1.8 GeV/c, and p/K up to 10 GeV/c. A key component to reach such a performance is a special 3-layer compound lens. This article describes the status of the High-Performance DIRC R&D for the EIC detector, with a focus on the detailed Monte Carlo simulation results and performance tests of the 3-layer lens.

Theoretical analysis and concept demonstration of a novel MOEMS accelerometer based on Raman—Nath diffraction

NASA Astrophysics Data System (ADS)

Zuwei, Zhang; Zhiyu, Wen; Jing, Hu

2012-04-01

The design and simulation of a novel microoptoelectromechanical system (MOEMS) accelerometer based on Raman—Nath diffraction are presented. The device is planned to be fabricated by microelectromechanical system technology and has a different sensing principle than the other reported MOEMS accelerometers. The fundamental theories and principles of the device are discussed in detail, a 3D finite element simulation of the flexural plate wave delay line oscillator is provided, and the operation frequency around 40 MHz is calculated. Finally, a lecture experiment is performed to demonstrate the feasibility of the device. This novel accelerometer is proposed to have the advantages of high sensitivity and anti-radiation, and has great potential for various applications.

The Physics of a Gymnastics Flight Element

NASA Astrophysics Data System (ADS)

Contakos, Jonas; Carlton, Les G.; Thompson, Bruce; Suddaby, Rick

2009-09-01

From its inception, performance in the sport of gymnastics has relied on the laws of physics to create movement patterns and static postures that appear almost impossible. In general, gymnastics is physics in motion and can provide an ideal framework for studying basic human modeling techniques and physical principles. Using low-end technology and basic principles of physics, we analyzed a high-end gymnastics skill competed in by both men and women. The comprehensive goal of the examination is to scientifically understand how a skill of this magnitude is actually physically possible and what must a gymnast do to successfully complete the skill. The examination is divided into three sections, each of which is comprehensive enough to be a separate assignment or small group project.

AB INITIO STUDY OF PHONON DISPERSION AND ELASTIC PROPERTIES OF L12 INTERMETALLICS Ti3Al AND Y3Al

NASA Astrophysics Data System (ADS)

Arikan, N.; Ersen, M.; Ocak, H. Y.; Iyigör, A.; Candan, A.; UǦUR, Ş.; UǦUR, G.; Khenata, R.; Varshney, D.

2013-12-01

In this paper, the structural, elastic and phonon properties of Ti3Al and Y3Al in L12(Cu3Al) phase are studied by performing first-principles calculations within the generalized gradient approximation. The calculated lattice constants, static bulk moduli, first-order pressure derivative of bulk moduli and elastic constants for both compounds are reported. The phonon dispersion curves along several high-symmetry lines at the Brillouin zone, together with the corresponding phonon density of states, are determined using the first-principles linear-response approach of the density functional perturbation theory. Temperature variations of specific heat in the range of 0-500 K are obtained using the quasi-harmonic model.

31 CFR 29.321 - General principle.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false General principle. 29.321 Section 29.321 Money and Finance: Treasury Office of the Secretary of the Treasury FEDERAL BENEFIT PAYMENTS UNDER....321 General principle. Any service performed after June 30, 1997, may never be credited toward Federal...

CEP's Eleven Principles of Effective Character Education

ERIC Educational Resources Information Center

Lickona, Tom; Schaps, Eric; Lewis, Catherine

2007-01-01

There is no single script for effective character education, but there are some important basic principles. This document presents eleven principles that schools and other groups can use to plan a character education effort and to evaluate available character education programs: (1) Promotes core ethical values and supportive performance values as…

Solving Accounting Problems: Differences between Accounting Experts and Novices.

ERIC Educational Resources Information Center

Marshall, P. Douglas

2002-01-01

Performance of 90 accounting experts (faculty and practitioners) and 60 novices (senior accounting majors) was compared. Experts applied more accounting principles to solving problems. There were no differences in types of principles applied and no correlation between (1) principles applied and number of breadth comments or (2) importance placed…

The Transfer of Abstract Principles Governing Complex Adaptive Systems

ERIC Educational Resources Information Center

Goldstone, Robert L.; Sakamoto, Yasuaki

2003-01-01

Four experiments explored participants' understanding of the abstract principles governing computer simulations of complex adaptive systems. Experiments 1, 2, and 3 showed better transfer of abstract principles across simulations that were relatively dissimilar, and that this effect was due to participants who performed relatively poorly on the…

CF60 Concrete Composition Design and Application on Fudiankou Xijiang Super Large Bridge

NASA Astrophysics Data System (ADS)

Qiu, Yi Mei; Wen, Sen Yuan; Chen, Jun Xiang

2018-06-01

Guangxi Wuzhou City Ring Road Fudiankou Xijiang super large bridge CF60 concrete is a new multi-phase composite high-performance concrete, this paper for the Fudiankou Xijiang bridge structure and characteristics of the project, in accordance with the principle of local materials and technical specification requirements, combined with the site conditions of CF60 engineering high performance concrete component materials, proportion and the technical performance, quantify the main physical and mechanical performance index. Analysis main influencing factors of the technical indicators, reasonable adjustment of concrete mix design parameters, and the use of technical means of admixture and multi-function composite admixture of concrete, obtain the optimal proportion of good work, process, mechanical properties stability and durability of engineering properties, recommend and verification of concrete mix; to explore the CF60 high performance concrete Soil in the Fudiankou Xijiang bridge application technology, detection and tracking the quality of concrete construction, concrete structure during the construction of the key technology and control points is proposed, evaluation of CF60 high performance concrete in the actual engineering application effect and benefit to ensure engineering quality of bridge structure and service life, and super long span bridge engineering construction to provide basis and reference.

Increasing the efficiency of photon collection in LArTPCs: the ARAPUCA light trap

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cancelo, G.; Cavanna, F.; Escobar, C. O.

The Liquid Argon Time Projection Chambers (LArTPCs) are a choice for the next generation of large neutrino detectors due to their optimal performance in particle tracking and calorimetry. The detection of Argon scintillation light plays a crucial role in the event reconstruction as well as the time reference for non-beam physics such as supernovae neutrino detection and baryon number violation studies. Here in this contribution, we present the current R&D work on the ARAPUCA (Argon R&D Advanced Program at UNICAMP), a light trap device to enhance Ar scintillation light collection and thus the overall performance of LArTPCs. The ARAPUCA workingmore » principle is based on a suitable combination of dichroic filters and wavelength shifters to achieve a high efficiency in light collection. We discuss the operational principles, the last results of laboratory tests and the application of the ARAPUCA as the alternative photon detection system in the protoDUNE detector.« less

Increasing the efficiency of photon collection in LArTPCs: the ARAPUCA light trap

DOE PAGES

Cancelo, G.; Cavanna, F.; Escobar, C. O.; ...

2018-03-26

The Liquid Argon Time Projection Chambers (LArTPCs) are a choice for the next generation of large neutrino detectors due to their optimal performance in particle tracking and calorimetry. The detection of Argon scintillation light plays a crucial role in the event reconstruction as well as the time reference for non-beam physics such as supernovae neutrino detection and baryon number violation studies. Here in this contribution, we present the current R&D work on the ARAPUCA (Argon R&D Advanced Program at UNICAMP), a light trap device to enhance Ar scintillation light collection and thus the overall performance of LArTPCs. The ARAPUCA workingmore » principle is based on a suitable combination of dichroic filters and wavelength shifters to achieve a high efficiency in light collection. We discuss the operational principles, the last results of laboratory tests and the application of the ARAPUCA as the alternative photon detection system in the protoDUNE detector.« less

Electrostatically Levitated Ring-Shaped Rotational-Gyro/Accelerometer

NASA Astrophysics Data System (ADS)

Murakoshi, Takao; Endo, Yasuo; Fukatsu, Keisuke; Nakamura, Sigeru; Esashi, Masayoshi

2003-04-01

This paper reports an electrostatically levitated inertia measurement system which is based on the principle of a rotational gyro. The device has several advantages: the levitation of the rotor in a vacuum eliminates mechanical friction resulting in high sensitivity; the position control for the levitation allows accelerations to be sensed in the tri-axis; and the fabrication of the device by a micromachining technique has the cost advantages afforded by miniaturization. Latest measurements yield a noise floor of the gyro and that of the accelerometer as low as 0.15 deg/h1/2 and 30 μG/Hz1/2, respectively. This performance is achieved by a new sensor design. To further improve of the previous device, a ring-shaped structure is designed and fabricated by deep reactive ion etching using inductively coupled plasma. The rotor levitation is performed with capacitive detection and electrostatic actuation. Multiaxis closed-loop control is realized by differential capacitance sensing and frequency multiplying. The rotation of the micro gyro is based on the principle of a planar variable capacitance motor.

The power of disruptive technological innovation: Transcatheter aortic valve implantation.

PubMed

Berlin, David B; Davidson, Michael J; Schoen, Frederick J

2015-11-01

We sought to evaluate the principles of disruptive innovation, defined as technology innovation that fundamentally shifts performance and utility metrics, as applied to transcatheter aortic valve implantation (TAVI). In particular, we considered implantation procedure, device design, cost, and patient population. Generally cheaper and lower performing, classical disruptive innovations are first commercialized in insignificant markets, promise lower margins, and often parasitize existing usage, representing unattractive investments for established market participants. However, despite presently high unit cost, TAVI is less invasive, treats a "new," generally high risk, patient population, and is generally done by a multidisciplinary integrated heart team. Moreover, at least in the short-term TAVI has not been lower-performing than open surgical aortic valve replacement in high-risk patients. We conclude that TAVI extends the paradigm of disruptive innovation and represents an attractive commercial opportunity space. Moreover, should the long-term performance and durability of TAVI approach that of conventional prostheses, TAVI will be an increasingly attractive commercial opportunity. © 2014 Wiley Periodicals, Inc.

MEMS actuators and sensors: observations on their performance and selection for purpose

NASA Astrophysics Data System (ADS)

Bell, D. J.; Lu, T. J.; Fleck, N. A.; Spearing, S. M.

2005-07-01

This paper presents an exercise in comparing the performance of microelectromechanical systems (MEMS) actuators and sensors as a function of operating principle. Data have been obtained from the literature for the mechanical performance characteristics of actuators, force sensors and displacement sensors. On-chip and off-chip actuators and sensors are each sub-grouped into families, classes and members according to their principle of operation. The performance of MEMS sharing common operating principles is compared with each other and with equivalent macroscopic devices. The data are used to construct performance maps showing the capability of existing actuators and sensors in terms of maximum force and displacement capability, resolution and frequency. These can also be used as a preliminary design tool, as shown in a case study on the design of an on-chip tensile test machine for materials in thin-film form.

Impact of Formulas, Language and Instruction on Student Performance on Cost-Volume-Profit Problems

ERIC Educational Resources Information Center

Johnson, Benny G.; Sargent, Carol Springer

2014-01-01

This study investigated how three factors impacted performance on cost-volume-profit homework problems: language, formula use, and instruction. Students enrolled in Introduction to Financial Accounting (the first principles of accounting course) and Managerial Accounting (the second principles of accounting course) from eight different US colleges…

The Relative Performance of Female and Male Students in Accounting Principles Classes.

ERIC Educational Resources Information Center

Bouillon, Marvin L.; Doran, B. Michael

1992-01-01

The performance of female and male students in Accounting Principles (AP) I and II was compared by using multiple regression techniques to assess the incremental explanatory effects of gender. Males significantly outperformed females in AP I, contradicting earlier studies. Similar gender of instructor and student was insignificant. (JOW)

Improving stability and curving passing performance for railway vehicles with a variable stiffness MRF rubber joint

NASA Astrophysics Data System (ADS)

Harris, B. J.; Sun, S. S.; Li, W. H.

2017-03-01

With the growing need for effective intercity transport, the need for more advanced rail vehicle technology has never been greater. The conflicting primary longitudinal suspension requirements of high speed stability and curving performance limit the development of rail vehicle technology. This paper presents a novel magnetorheological fluid based joint with variable stiffness characteristics for the purpose of overcoming this parameter conflict. Firstly, the joint design and working principle is developed. Following this, a prototype is tested by MTS to characterize its variable stiffness properties under a range of conditions. Lastly, the performance of the proposed MRF rubber joint with regard to improving train stability and curving performance is numerically evaluated.

Accurate prediction of the refractive index of polymers using first principles and data modeling

NASA Astrophysics Data System (ADS)

Afzal, Mohammad Atif Faiz; Cheng, Chong; Hachmann, Johannes

Organic polymers with a high refractive index (RI) have recently attracted considerable interest due to their potential application in optical and optoelectronic devices. The ability to tailor the molecular structure of polymers is the key to increasing the accessible RI values. Our work concerns the creation of predictive in silico models for the optical properties of organic polymers, the screening of large-scale candidate libraries, and the mining of the resulting data to extract the underlying design principles that govern their performance. This work was set up to guide our experimentalist partners and allow them to target the most promising candidates. Our model is based on the Lorentz-Lorenz equation and thus includes the polarizability and number density values for each candidate. For the former, we performed a detailed benchmark study of different density functionals, basis sets, and the extrapolation scheme towards the polymer limit. For the number density we devised an exceedingly efficient machine learning approach to correlate the polymer structure and the packing fraction in the bulk material. We validated the proposed RI model against the experimentally known RI values of 112 polymers. We could show that the proposed combination of physical and data modeling is both successful and highly economical to characterize a wide range of organic polymers, which is a prerequisite for virtual high-throughput screening.

NiTi-Enabled Composite Design for Exceptional Performances

DOE PAGES

Shao, Yang; Guo, Fangmin; Ren, Yang; ...

2017-03-08

In an effort to further develop shape memory alloys (SMAs) for functional applications, much focus has been given in recent years to design and create innovative forms of SMAs, such as functionally graded SMAs, architecture SMAs, and SMA-based metallic composites. Here, we reports on the progress in creating NiTi-based composites of exceptional properties stimulated by the recent discovery of the principle of lattice strain matching between the SMA matrix and superelastic nanoinclusions embedded in the matrix. And based on this principle, different SMA–metal composites have been designed to achieve extraordinary shape memory performances, such as complete pseudoelastic behavior at asmore » low as 77 K and stress plateau as high as 1600 MPa, and exceptional mechanical properties, such as tensile strength as high as 2000 MPa and Young’s modulus as low as 28 GPa. Details are given for a NiTi–W micro-fiber composite prepared by melt infiltration, hot pressing, forging, and cold rolling. Furthermore, the composite contained 63% in volume of W micro-fibers of ~0.6 μm thickness. In situ synchrotron X-ray diffraction revealed that the NiTi matrix underwent martensite transformation during tensile deformation while the W micro-fiber deformed elastically with a maximum strain of 0.83% in the loading direction, implying a W fiber stress of 3280 MPa. The composite showed a maximum high tensile strength of 2300 MPa.« less

A theoretical prediction of super high-performance thermoelectric materials based on MoS2/WS2 hybrid nanoribbons

NASA Astrophysics Data System (ADS)

Zhang, Zhongwei; Xie, Yuee; Peng, Qing; Chen, Yuanping

2016-02-01

Modern society is hungry for electrical power. To improve the efficiency of energy harvesting from heat, extensive efforts seek high-performance thermoelectric materials that possess large differences between electronic and thermal conductance. Here we report a super high-performance material of consisting of MoS2/WS2 hybrid nanoribbons discovered from a theoretical investigation using nonequilibrium Green’s function methods combined with first-principles calculations and molecular dynamics simulations. The hybrid nanoribbons show higher efficiency of energy conversion than the MoS2 and WS2 nanoribbons due to the fact that the MoS2/WS2 interface reduces lattice thermal conductivity more than the electron transport. By tuning the number of the MoS2/WS2 interfaces, a figure of merit ZT as high as 5.5 is achieved at a temperature of 600 K. Our results imply that the MoS2/WS2 hybrid nanoribbons have promising applications in thermal energy harvesting.

A theoretical prediction of super high-performance thermoelectric materials based on MoS2/WS2 hybrid nanoribbons

PubMed Central

Zhang, Zhongwei; Xie, Yuee; Peng, Qing; Chen, Yuanping

2016-01-01

Modern society is hungry for electrical power. To improve the efficiency of energy harvesting from heat, extensive efforts seek high-performance thermoelectric materials that possess large differences between electronic and thermal conductance. Here we report a super high-performance material of consisting of MoS2/WS2 hybrid nanoribbons discovered from a theoretical investigation using nonequilibrium Green’s function methods combined with first-principles calculations and molecular dynamics simulations. The hybrid nanoribbons show higher efficiency of energy conversion than the MoS2 and WS2 nanoribbons due to the fact that the MoS2/WS2 interface reduces lattice thermal conductivity more than the electron transport. By tuning the number of the MoS2/WS2 interfaces, a figure of merit ZT as high as 5.5 is achieved at a temperature of 600 K. Our results imply that the MoS2/WS2 hybrid nanoribbons have promising applications in thermal energy harvesting. PMID:26884123

A Model to Measure Bombardier/Navigator Performance during Radar Navigation in Device 2F114, A-6E Weapon System Trainer.

DTIC Science & Technology

1981-03-01

systems, sub- systems, equipment, weapons, tactics, missions, etc. Concepts and Principles - Fundamental truths, ideas, opinions and thoughts formed from...verification, etc. Grasping the meaning of concepts and principles , i.e., understanding the basic principles of infrared and radar detection. Understanding...concepts, principles , procedures, etc.). Analysis A demonstration of a learned process of breaking down material (i.e., data, other information) into

Design of high reliability organizations in health care.

PubMed

Carroll, J S; Rudolph, J W

2006-12-01

To improve safety performance, many healthcare organizations have sought to emulate high reliability organizations from industries such as nuclear power, chemical processing, and military operations. We outline high reliability design principles for healthcare organizations including both the formal structures and the informal practices that complement those structures. A stage model of organizational structures and practices, moving from local autonomy to formal controls to open inquiry to deep self-understanding, is used to illustrate typical challenges and design possibilities at each stage. We suggest how organizations can use the concepts and examples presented to increase their capacity to self-design for safety and reliability.

Caustic Singularities Of High-Gain, Dual-Shaped Reflectors

NASA Technical Reports Server (NTRS)

Galindo, Victor; Veruttipong, Thavath W.; Imbriale, William A.; Rengarajan, Sambiam

1991-01-01

Report presents study of some sources of error in analysis, by geometric theory of diffraction (GTD), of performance of high-gain, dual-shaped antenna reflector. Study probes into underlying analytic causes of singularity, with view toward devising and testing practical methods to avoid problems caused by singularity. Hybrid physical optics (PO) approach used to study near-field spillover or noise-temperature characteristics of high-gain relector antenna efficiently and accurately. Report illustrates this approach and underlying principles by presenting numerical results, for both offset and symmetrical reflector systems, computed by GTD, PO, and PO/GO methods.

Dynamic frequency-domain interferometer for absolute distance measurements with high resolution

NASA Astrophysics Data System (ADS)

Weng, Jidong; Liu, Shenggang; Ma, Heli; Tao, Tianjiong; Wang, Xiang; Liu, Cangli; Tan, Hua

2014-11-01

A unique dynamic frequency-domain interferometer for absolute distance measurement has been developed recently. This paper presents the working principle of the new interferometric system, which uses a photonic crystal fiber to transmit the wide-spectrum light beams and a high-speed streak camera or frame camera to record the interference stripes. Preliminary measurements of harmonic vibrations of a speaker, driven by a radio, and the changes in the tip clearance of a rotating gear wheel show that this new type of interferometer has the ability to perform absolute distance measurements both with high time- and distance-resolution.

The Gestalt Principle of Similarity Benefits Visual Working Memory

PubMed Central

Peterson, Dwight J.; Berryhill, Marian E.

2013-01-01

Visual working memory (VWM) is essential for many cognitive processes yet it is notably limited in capacity. Visual perception processing is facilitated by Gestalt principles of grouping, such as connectedness, similarity, and proximity. This introduces the question: do these perceptual benefits extend to VWM? If so, can this be an approach to enhance VWM function by optimizing the processing of information? Previous findings demonstrate that several Gestalt principles (connectedness, common region, and spatial proximity) do facilitate VWM performance in change detection tasks (Woodman, Vecera, & Luck, 2003; Xu, 2002a, 2006; Xu & Chun, 2007; Jiang, Olson & Chun, 2000). One prevalent Gestalt principle, similarity, has not been examined with regard to facilitating VWM. Here, we investigated whether grouping by similarity benefits VWM. Experiment 1 established the basic finding that VWM performance could benefit from grouping. Experiment 2 replicated and extended this finding by showing that similarity was only effective when the similar stimuli were proximal. In short, the VWM performance benefit derived from similarity was constrained by spatial proximity such that similar items need to be near each other. Thus, the Gestalt principle of similarity benefits visual perception, but it can provide benefits to VWM as well. PMID:23702981

The Gestalt principle of similarity benefits visual working memory.

PubMed

Peterson, Dwight J; Berryhill, Marian E

2013-12-01

Visual working memory (VWM) is essential for many cognitive processes, yet it is notably limited in capacity. Visual perception processing is facilitated by Gestalt principles of grouping, such as connectedness, similarity, and proximity. This introduces the question, do these perceptual benefits extend to VWM? If so, can this be an approach to enhance VWM function by optimizing the processing of information? Previous findings have demonstrated that several Gestalt principles (connectedness, common region, and spatial proximity) do facilitate VWM performance in change detection tasks (Jiang, Olson, & Chun, 2000; Woodman, Vecera, & Luck, 2003; Xu, 2002, 2006; Xu & Chun, 2007). However, one prevalent Gestalt principle, similarity, has not been examined with regard to facilitating VWM. Here, we investigated whether grouping by similarity benefits VWM. Experiment 1 established the basic finding that VWM performance could benefit from grouping. Experiment 2 replicated and extended this finding by showing that similarity was only effective when the similar stimuli were proximal. In short, the VWM performance benefit derived from similarity was constrained by spatial proximity, such that similar items need to be near each other. Thus, the Gestalt principle of similarity benefits visual perception, but it can provide benefits to VWM as well.

Deploying Team Science Principles to Optimize Interdisciplinary Lung Cancer Care Delivery: Avoiding the Long and Winding Road to Optimal Care.

PubMed

Osarogiagbon, Raymond U; Rodriguez, Hector P; Hicks, Danielle; Signore, Raymond S; Roark, Kristi; Kedia, Satish K; Ward, Kenneth D; Lathan, Christopher; Santarella, Scott; Gould, Michael K; Krasna, Mark J

2016-11-01

The complexity of lung cancer care mandates interaction between clinicians with different skill sets and practice cultures in the routine delivery of care. Using team science principles and a case-based approach, we exemplify the need for the development of real care teams for patients with lung cancer to foster coordination among the multiple specialists and staff engaged in routine care delivery. Achieving coordinated lung cancer care is a high-priority public health challenge because of the volume of patients, lethality of disease, and well-described disparities in quality and outcomes of care. Coordinating mechanisms need to be cultivated among different types of specialist physicians and care teams, with differing technical expertise and practice cultures, who have traditionally functioned more as coactively working groups than as real teams. Coordinating mechanisms, including shared mental models, high-quality communication, mutual trust, and mutual performance monitoring, highlight the challenge of achieving well-coordinated care and illustrate how team science principles can be used to improve quality and outcomes of lung cancer care. To develop the evidence base to support coordinated lung cancer care, research comparing the effectiveness of a diverse range of multidisciplinary care team approaches and interorganizational coordinating mechanisms should be promoted.

Principles Underpinning Graded Assessment in VET: A Critique of Prevailing Perceptions

ERIC Educational Resources Information Center

Gillis, Shelley; Griffin, Patrick

2005-01-01

To help achieve national consistency of assessment and reporting in the Australian Vocational Education and Training sector, there is a need to develop a set of national principles for graded performance assessment. This paper challenges a number of prevailing principles from both a theoretical and assessment perspective, namely that grades must…

Sources of Funding and Academic Performance in Economics Principles Courses

ERIC Educational Resources Information Center

Faulk, Dagney; Srinivasan, Arun K.; Bingham, Jon

2012-01-01

The authors examine two factors that may affect student achievement in economics principles courses: working for pay and the primary source of funds (employer tuition reimbursement, loans, scholarships, financial aid, self-financing, parental transfers, other) used to pay for college for a sample of students in economics principles classes at a…

Re-Visiting the Competence/Performance Debate in the Acquisition of the Counting Principles

ERIC Educational Resources Information Center

Le Corre, Mathieu; Van de Walle, Gretchen; Brannon, Elizabeth M.; Carey, Susan.

2006-01-01

Advocates of the ''continuity hypothesis'' have argued that innate non-verbal counting principles guide the acquisition of the verbal count list (Gelman & Gallistel, 1978). Some studies have supported this hypothesis, but others have suggested that the counting principles must be constructed anew by each child. Defenders of the continuity…

Fibrous hybrid of graphene and sulfur nanocrystals for high-performance lithium-sulfur batteries.

PubMed

Zhou, Guangmin; Yin, Li-Chang; Wang, Da-Wei; Li, Lu; Pei, Songfeng; Gentle, Ian Ross; Li, Feng; Cheng, Hui-Ming

2013-06-25

Graphene-sulfur (G-S) hybrid materials with sulfur nanocrystals anchored on interconnected fibrous graphene are obtained by a facile one-pot strategy using a sulfur/carbon disulfide/alcohol mixed solution. The reduction of graphene oxide and the formation/binding of sulfur nanocrystals were integrated. The G-S hybrids exhibit a highly porous network structure constructed by fibrous graphene, many electrically conducting pathways, and easily tunable sulfur content, which can be cut and pressed into pellets to be directly used as lithium-sulfur battery cathodes without using a metal current-collector, binder, and conductive additive. The porous network and sulfur nanocrystals enable rapid ion transport and short Li(+) diffusion distance, the interconnected fibrous graphene provides highly conductive electron transport pathways, and the oxygen-containing (mainly hydroxyl/epoxide) groups show strong binding with polysulfides, preventing their dissolution into the electrolyte based on first-principles calculations. As a result, the G-S hybrids show a high capacity, an excellent high-rate performance, and a long life over 100 cycles. These results demonstrate the great potential of this unique hybrid structure as cathodes for high-performance lithium-sulfur batteries.

Chemical intuition for high thermoelectric performance in monolayer black phosphorus, α-arsenene and aW-antimonene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peng, Bo; Zhang, Hao; Shao, Hezhu

Identifying materials with intrinsically high thermoelectric performance remains a challenge even with the aid of a high-throughput search. Here, using a chemically intuitive approach based on the bond-orbital theory, three anisotropic 2D group-V materials (monolayer black phosphorus, α-arsenene, and aW-antimonene) are identified as candidates for high thermoelectric energy conversion efficiency. Concepts, such as bond length, bond angle, and bond strength, are used to explain the trends in their electronic properties, such as the band gap and the effective mass. Our first principles calculations confirm that high carrier mobilities and large Seebeck coefficients can be obtained at the same time inmore » these materials, due to complex Fermi surfaces originating from the anisotropic structures. An intuitive understanding of how the bonding character affects phonon transport is also provided with emphasis on the importance of bonding strength and bond anharmonicity. High thermoelectric performance is observed in these materials. In conclusion, our approach provides a powerful tool to identify new thermoelectric materials and evaluate their transport properties.« less

Chemical intuition for high thermoelectric performance in monolayer black phosphorus, α-arsenene and aW-antimonene

DOE PAGES

Peng, Bo; Zhang, Hao; Shao, Hezhu; ...

2017-11-21

Identifying materials with intrinsically high thermoelectric performance remains a challenge even with the aid of a high-throughput search. Here, using a chemically intuitive approach based on the bond-orbital theory, three anisotropic 2D group-V materials (monolayer black phosphorus, α-arsenene, and aW-antimonene) are identified as candidates for high thermoelectric energy conversion efficiency. Concepts, such as bond length, bond angle, and bond strength, are used to explain the trends in their electronic properties, such as the band gap and the effective mass. Our first principles calculations confirm that high carrier mobilities and large Seebeck coefficients can be obtained at the same time inmore » these materials, due to complex Fermi surfaces originating from the anisotropic structures. An intuitive understanding of how the bonding character affects phonon transport is also provided with emphasis on the importance of bonding strength and bond anharmonicity. High thermoelectric performance is observed in these materials. In conclusion, our approach provides a powerful tool to identify new thermoelectric materials and evaluate their transport properties.« less

Development and preliminary evidence for the validity of an instrument assessing implementation of human-factors principles in medication-related decision-support systems—I-MeDeSA

PubMed Central

Zachariah, Marianne; Seidling, Hanna M; Neri, Pamela M; Cresswell, Kathrin M; Duke, Jon; Bloomrosen, Meryl; Volk, Lynn A; Bates, David W

2011-01-01

Background Medication-related decision support can reduce the frequency of preventable adverse drug events. However, the design of current medication alerts often results in alert fatigue and high over-ride rates, thus reducing any potential benefits. Methods The authors previously reviewed human-factors principles for relevance to medication-related decision support alerts. In this study, instrument items were developed for assessing the appropriate implementation of these human-factors principles in drug–drug interaction (DDI) alerts. User feedback regarding nine electronic medical records was considered during the development process. Content validity, construct validity through correlation analysis, and inter-rater reliability were assessed. Results The final version of the instrument included 26 items associated with nine human-factors principles. Content validation on three systems resulted in the addition of one principle (Corrective Actions) to the instrument and the elimination of eight items. Additionally, the wording of eight items was altered. Correlation analysis suggests a direct relationship between system age and performance of DDI alerts (p=0.0016). Inter-rater reliability indicated substantial agreement between raters (κ=0.764). Conclusion The authors developed and gathered preliminary evidence for the validity of an instrument that measures the appropriate use of human-factors principles in the design and display of DDI alerts. Designers of DDI alerts may use the instrument to improve usability and increase user acceptance of medication alerts, and organizations selecting an electronic medical record may find the instrument helpful in meeting their clinicians' usability needs. PMID:21946241

Assessing climate change-robustness of protected area management plans-The case of Germany.

PubMed

Geyer, Juliane; Kreft, Stefan; Jeltsch, Florian; Ibisch, Pierre L

2017-01-01

Protected areas are arguably the most important instrument of biodiversity conservation. To keep them fit under climate change, their management needs to be adapted to address related direct and indirect changes. In our study we focus on the adaptation of conservation management planning, evaluating management plans of 60 protected areas throughout Germany with regard to their climate change-robustness. First, climate change-robust conservation management was defined using 11 principles and 44 criteria, which followed an approach similar to sustainability standards. We then evaluated the performance of individual management plans concerning the climate change-robustness framework. We found that climate change-robustness of protected areas hardly exceeded 50 percent of the potential performance, with most plans ranking in the lower quarter. Most Natura 2000 protected areas, established under conservation legislation of the European Union, belong to the sites with especially poor performance, with lower values in smaller areas. In general, the individual principles showed very different rates of accordance with our principles, but similarly low intensity. Principles with generally higher performance values included holistic knowledge management, public accountability and acceptance as well as systemic and strategic coherence. Deficiencies were connected to dealing with the future and uncertainty. Lastly, we recommended the presented principles and criteria as essential guideposts that can be used as a checklist for working towards more climate change-robust planning.

Assessing climate change-robustness of protected area management plans—The case of Germany

PubMed Central

Geyer, Juliane; Kreft, Stefan; Jeltsch, Florian; Ibisch, Pierre L.

2017-01-01

Protected areas are arguably the most important instrument of biodiversity conservation. To keep them fit under climate change, their management needs to be adapted to address related direct and indirect changes. In our study we focus on the adaptation of conservation management planning, evaluating management plans of 60 protected areas throughout Germany with regard to their climate change-robustness. First, climate change-robust conservation management was defined using 11 principles and 44 criteria, which followed an approach similar to sustainability standards. We then evaluated the performance of individual management plans concerning the climate change-robustness framework. We found that climate change-robustness of protected areas hardly exceeded 50 percent of the potential performance, with most plans ranking in the lower quarter. Most Natura 2000 protected areas, established under conservation legislation of the European Union, belong to the sites with especially poor performance, with lower values in smaller areas. In general, the individual principles showed very different rates of accordance with our principles, but similarly low intensity. Principles with generally higher performance values included holistic knowledge management, public accountability and acceptance as well as systemic and strategic coherence. Deficiencies were connected to dealing with the future and uncertainty. Lastly, we recommended the presented principles and criteria as essential guideposts that can be used as a checklist for working towards more climate change-robust planning. PMID:28982187

An Empirical Investigation of Clicker Technology in Financial Accounting Principles

ERIC Educational Resources Information Center

Marshall, Leisa L.; Varnon, Anthony W.

2012-01-01

The effects of clicker-use and active learning classroom activities on student performance in financial accounting principles were examined. A repeated measure design was used to compare performance on four exams between a clicker group and a non-clicker group, after controlling for GPA and age. A matched-pairs t-test was used to compare the…

Student Outcomes in Economics Principles: Online vs. Face-to-Face Delivery

ERIC Educational Resources Information Center

Birkeland, Kathryn; Weinandt, Mandie; Carr, David L.

2015-01-01

This study looks at the performance of students in an online and face-to-face section of economic principles with the same instructor. After controlling for the bias of students selecting the online section and observable characteristics, we did not find any statistical difference in the exam performance of students across delivery modes of the…

A Quantitative Evaluation of the Flipped Classroom in a Large Lecture Principles of Economics Course

ERIC Educational Resources Information Center

Balaban, Rita A.; Gilleskie, Donna B.; Tran, Uyen

2016-01-01

This research provides evidence that the flipped classroom instructional format increases student final exam performance, relative to the traditional instructional format, in a large lecture principles of economics course. The authors find that the flipped classroom directly improves performance by 0.2 to 0.7 standardized deviations, depending on…

An Online Premium? Characteristics and Performance of Online versus Face-to-Face Students in Principles of Microeconomics

ERIC Educational Resources Information Center

Dendir, Seife

2016-01-01

The author uses data from two Principles of Microeconomics courses to examine differences in characteristics and performance of online versus face-to-face students. The analysis indicates that even in a traditional institution, the two delivery modes may be serving students with distinctly different backgrounds and characteristics. In terms of…

Relationships between Learning Styles and Academic Achievement and Brain Hemispheric Dominance and Academic Performance in Business and Accounting Courses.

ERIC Educational Resources Information Center

Carthey, Joseph H.

A study determined if relationships exist between learning styles and academic achievement and brain hemispheric dominance and academic performance in the courses of principles of management, business law, intermediate accounting, and principles of economics. All second-year accounting students (64 students) at Northeast Iowa Community College…

Progress of OLED devices with high efficiency at high luminance

NASA Astrophysics Data System (ADS)

Nguyen, Carmen; Ingram, Grayson; Lu, Zhenghong

2014-03-01

Organic light emitting diodes (OLEDs) have progressed significantly over the last two decades. For years, OLEDs have been promoted as the next generation technology for flat panel displays and solid-state lighting due to their potential for high energy efficiency and dynamic range of colors. Although high efficiency can readily be obtained at low brightness levels, a significant decline at high brightness is commonly observed. In this report, we will review various strategies for achieving highly efficient phosphorescent OLED devices at high luminance. Specifically, we will provide details regarding the performance and general working principles behind each strategy. We will conclude by looking at how some of these strategies can be combined to produce high efficiency white OLEDs at high brightness.

Teaching Principles of Economics Without Lectures

ERIC Educational Resources Information Center

McConnell, Campbell R.; Lamphear, Charles

1969-01-01

Presents important evidence thatstudents taking principles of economics with lectures, and those taking the course on a lectureless basis performed equally well on an intensive battery of objective examinations." (Editor)

Exploring long-wave infrared transmitting materials with AxBy form: First-principles gene-like studies.

PubMed

Du, Jia-Ren; Chen, Nian-Ke; Li, Xian-Bin; Xie, Sheng-Yi; Tian, Wei Quan; Wang, Xian-Yin; Tu, Hai-Ling; Sun, Hong-Bo

2016-02-23

Long-wave infrared (8-12 μm) transmitting materials play critical roles in space science and electronic science. However, the paradox between their mechanical strength and infrared transmitting performance seriously prohibits their applications in harsh external environment. From the experimental view, searching a good window material compatible with both properties is a vast trail-and-error engineering project, which is not readily achieved efficiently. In this work, we propose a very simple and efficient method to explore potential infrared window materials with suitable mechanical property by first-principles gene-like searching. Two hundred and fifty-three potential materials are evaluated to find their bulk modulus (for mechanical performance) and phonon vibrational frequency (for optical performance). Seven new potential candidates are selected, namely TiSe, TiS, MgS, CdF2, HgF2, CdO, and SrO. Especially, the performances of TiS and CdF2 can be comparable to that of the most popular commercial ZnS at high temperature. Finally, we propose possible ranges of infrared transmission for halogen, chalcogen and nitrogen compounds respectively to guide further exploration. The present strategy to explore IR window materials can significantly speed up the new development progress. The same idea can be used for other material rapid searching towards special functions and applications.

SEALDH-II-An Autonomous, Holistically Controlled, First Principles TDLAS Hygrometer for Field and Airborne Applications: Design-Setup-Accuracy/Stability Stress Test.

PubMed

Buchholz, Bernhard; Kallweit, Sören; Ebert, Volker

2016-12-30

Instrument operation in harsh environments often significantly impacts the trust level of measurement data. While commercial instrument manufacturers clearly define the deployment conditions to achieve trustworthy data in typical standard applications, it is frequently unavoidable in scientific field applications to operate instruments outside these commercial standard application specifications. Scientific instrumentation, however, is employing cutting-edge technology and often highly optimized but also lacks long-term field tests to assess the field vs. laboratory performance. Recently, we developed the Selective Extractive Laser Diode Hygrometer (SEALDH-II), which addresses field and especially airborne applications as well as metrological laboratory validations. SEALDH-II targets reducing deviations between airborne hygrometers (currently up to 20% between the most advanced hygrometers) with a new holistic, internal control and validation concept, which guarantees the transfer of the laboratory performance into a field scenario by capturing more than 80 instrument internal "housekeeping" data to nearly perfectly control SEALDH-II's health status. SEALDH-II uses a calibration-free, first principles based, direct Tuneable Diode Laser Absorption Spectroscopy (dTDLAS) approach, to cover the entire atmospheric humidity measurement range from about 3 to 40,000 ppmv with a calculated maximum uncertainty of 4.3% ± 3 ppmv. This is achieved not only by innovations in internal instrument monitoring and design, but also by active control algorithms such as a high resolution spectral stabilization. This paper describes the setup, working principles, and instrument stabilization, as well as its precision validation and long-term stress tests in an environmental chamber over an environmental temperature and humidity range of ΔT = 50 K and ΔRH = 80% RH, respectively.

SEALDH-II—An Autonomous, Holistically Controlled, First Principles TDLAS Hygrometer for Field and Airborne Applications: Design–Setup–Accuracy/Stability Stress Test

PubMed Central

Buchholz, Bernhard; Kallweit, Sören; Ebert, Volker

2016-01-01

Instrument operation in harsh environments often significantly impacts the trust level of measurement data. While commercial instrument manufacturers clearly define the deployment conditions to achieve trustworthy data in typical standard applications, it is frequently unavoidable in scientific field applications to operate instruments outside these commercial standard application specifications. Scientific instrumentation, however, is employing cutting-edge technology and often highly optimized but also lacks long-term field tests to assess the field vs. laboratory performance. Recently, we developed the Selective Extractive Laser Diode Hygrometer (SEALDH-II), which addresses field and especially airborne applications as well as metrological laboratory validations. SEALDH-II targets reducing deviations between airborne hygrometers (currently up to 20% between the most advanced hygrometers) with a new holistic, internal control and validation concept, which guarantees the transfer of the laboratory performance into a field scenario by capturing more than 80 instrument internal “housekeeping” data to nearly perfectly control SEALDH-II’s health status. SEALDH-II uses a calibration-free, first principles based, direct Tuneable Diode Laser Absorption Spectroscopy (dTDLAS) approach, to cover the entire atmospheric humidity measurement range from about 3 to 40,000 ppmv with a calculated maximum uncertainty of 4.3% ± 3 ppmv. This is achieved not only by innovations in internal instrument monitoring and design, but also by active control algorithms such as a high resolution spectral stabilization. This paper describes the setup, working principles, and instrument stabilization, as well as its precision validation and long-term stress tests in an environmental chamber over an environmental temperature and humidity range of ΔT = 50 K and ΔRH = 80% RH, respectively. PMID:28042844

High-Performance First-Principles Molecular Dynamics for Predictive Theory and Modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gygi, Francois; Galli, Giulia; Schwegler, Eric

This project focused on developing high-performance software tools for First-Principles Molecular Dynamics (FPMD) simulations, and applying them in investigations of materials relevant to energy conversion processes. FPMD is an atomistic simulation method that combines a quantum-mechanical description of electronic structure with the statistical description provided by molecular dynamics (MD) simulations. This reliance on fundamental principles allows FPMD simulations to provide a consistent description of structural, dynamical and electronic properties of a material. This is particularly useful in systems for which reliable empirical models are lacking. FPMD simulations are increasingly used as a predictive tool for applications such as batteries, solarmore » energy conversion, light-emitting devices, electro-chemical energy conversion devices and other materials. During the course of the project, several new features were developed and added to the open-source Qbox FPMD code. The code was further optimized for scalable operation of large-scale, Leadership-Class DOE computers. When combined with Many-Body Perturbation Theory (MBPT) calculations, this infrastructure was used to investigate structural and electronic properties of liquid water, ice, aqueous solutions, nanoparticles and solid-liquid interfaces. Computing both ionic trajectories and electronic structure in a consistent manner enabled the simulation of several spectroscopic properties, such as Raman spectra, infrared spectra, and sum-frequency generation spectra. The accuracy of the approximations used allowed for direct comparisons of results with experimental data such as optical spectra, X-ray and neutron diffraction spectra. The software infrastructure developed in this project, as applied to various investigations of solids, liquids and interfaces, demonstrates that FPMD simulations can provide a detailed, atomic-scale picture of structural, vibrational and electronic properties of complex systems relevant to energy conversion devices.« less

Design and Test Research on Cutting Blade of Corn Harvester Based on Bionic Principle.

PubMed

Tian, Kunpeng; Li, Xianwang; Zhang, Bin; Chen, Qiaomin; Shen, Cheng; Huang, Jicheng

2017-01-01

Existing corn harvester cutting blades have problems associated with large cutting resistance, high energy consumption, and poor cut quality. Using bionics principles, a bionic blade was designed by extracting the cutting tooth profile curve of the B. horsfieldi palate. Using a double-blade cutting device testing system, a single stalk cutting performance contrast test for corn stalks obtained at harvest time was carried out. Results show that bionic blades have superior performance, demonstrated by strong cutting ability and good cut quality. Using statistical analysis of two groups of cutting test data, the average cutting force and cutting energy of bionic blades and ordinary blades were obtained as 480.24 N and 551.31 N and 3.91 J and 4.38 J, respectively. Average maximum cutting force and cutting energy consumption for the bionic blade were reduced by 12.89% and 10.73%, respectively. Variance analysis showed that both blade types had a significant effect on maximum cutting energy and cutting energy required to cut a corn stalk. This demonstrates that bionic blades have better cutting force and energy consumption reduction performance than ordinary blades.

Solutions for Failing High Schools: Converging Visions and Promising Models.

ERIC Educational Resources Information Center

Legters, Nettie; Balfanz, Robert; McPartland, James

Promising solutions to the failings of traditional comprehensive high schools were reviewed to identify basic principles and strategies for improving high schools nationwide. Selected research studies, policy documents, and promising high school programs were reviewed. The review revealed the following principles for helping high schools better…

First-principles design of nanostructured hybrid photovoltaics based on layered transition metal phosphates

DOE PAGES

Lentz, Levi C.; Kolpak, Alexie M.

2017-04-28

The performance of bulk organic and hybrid organic-inorganic heterojunction photovoltaics is often limited by high carrier recombination arising from strongly bound excitons and low carrier mobility. Structuring materials to minimize the length scales required for exciton separation and carrier collection is therefore a promising approach for improving efficiency. In this work, first-principles computations are employed to design and characterize a new class of photovoltaic materials composed of layered transition metal phosphates (TMPs) covalently bound to organic absorber molecules to form nanostructured superlattices. Using a combination of transition metal substitution and organic functionalization, the electronic structure of these materials is systematicallymore » tuned to design a new hybrid photovoltaic material predicted to exhibit very low recombination due to the presence of a local electric field and spatially isolated, high mobility, two-dimensional electron and hole conducting channels. Furthermore, this material is predicted to have a large open-circuit voltage of 1.7 V. Here, this work suggests that hybrid TMPs constitute an interesting class of materials for further investigation in the search for achieving high efficiency, high power, and low cost photo Zirconium phosphate was chosen, in part, due to previous experiment voltaics.« less

First-principles design of nanostructured hybrid photovoltaics based on layered transition metal phosphates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lentz, Levi C.; Kolpak, Alexie M.

The performance of bulk organic and hybrid organic-inorganic heterojunction photovoltaics is often limited by high carrier recombination arising from strongly bound excitons and low carrier mobility. Structuring materials to minimize the length scales required for exciton separation and carrier collection is therefore a promising approach for improving efficiency. In this work, first-principles computations are employed to design and characterize a new class of photovoltaic materials composed of layered transition metal phosphates (TMPs) covalently bound to organic absorber molecules to form nanostructured superlattices. Using a combination of transition metal substitution and organic functionalization, the electronic structure of these materials is systematicallymore » tuned to design a new hybrid photovoltaic material predicted to exhibit very low recombination due to the presence of a local electric field and spatially isolated, high mobility, two-dimensional electron and hole conducting channels. Furthermore, this material is predicted to have a large open-circuit voltage of 1.7 V. Here, this work suggests that hybrid TMPs constitute an interesting class of materials for further investigation in the search for achieving high efficiency, high power, and low cost photo Zirconium phosphate was chosen, in part, due to previous experiment voltaics.« less

The punctum fixum-punctum mobile model: a neuromuscular principle for efficient movement generation?

PubMed

von Laßberg, Christoph; Rapp, Walter

2015-01-01

According to the "punctum fixum-punctum mobile model" that was introduced in prior studies, for generation of the most effective intentional acceleration of a body part the intersegmental neuromuscular onset succession has to spread successively from the rotation axis (punctum fixum) toward the body part that shall be accelerated (punctum mobile). The aim of the present study was to investigate whether this principle is, indeed, fundamental for any kind of efficient rotational accelerations in general, independent of the kind of movements, type of rotational axis, the current body position, or movement direction. Neuromuscular onset succession was captured by surface electromyography of relevant muscles of the anterior and posterior muscle chain in 16 high-level gymnasts during intentional accelerating movement phases while performing 18 different gymnastics elements (in various body positions to forward and backward, performed on high bar, parallel bars, rings and trampoline), as well as during non-sport specific pivot movements around the longitudinal axis. The succession patterns to generate the acceleration phases during these movements were described and statistically evaluated based on the onset time difference between the muscles of the corresponding muscle chain. In all the analyzed movement phases, the results clearly support the hypothesized succession pattern from punctum fixum to punctum mobile. This principle was further underlined by the finding that the succession patterns do change their direction running through the body when the rotational axis (punctum fixum) has been changed (e.g., high bar or rings [hands] vs. floor or trampoline [feet]). The findings improve our understanding of intersegmental neuromuscular coordination patterns to generate intentional movements most efficiently. This could help to develop more specific methods to facilitate such patterns in particular contexts, thus allowing for shorter motor learning procedures of context-specific key movement sequences in different disciplines of sports, as well as during non-sport specific movements.

The Punctum Fixum-Punctum Mobile Model: A Neuromuscular Principle for Efficient Movement Generation?

PubMed Central

von Laßberg, Christoph; Rapp, Walter

2015-01-01

According to the “punctum fixum–punctum mobile model” that was introduced in prior studies, for generation of the most effective intentional acceleration of a body part the intersegmental neuromuscular onset succession has to spread successively from the rotation axis (punctum fixum) toward the body part that shall be accelerated (punctum mobile). The aim of the present study was to investigate whether this principle is, indeed, fundamental for any kind of efficient rotational accelerations in general, independent of the kind of movements, type of rotational axis, the current body position, or movement direction. Neuromuscular onset succession was captured by surface electromyography of relevant muscles of the anterior and posterior muscle chain in 16 high-level gymnasts during intentional accelerating movement phases while performing 18 different gymnastics elements (in various body positions to forward and backward, performed on high bar, parallel bars, rings and trampoline), as well as during non-sport specific pivot movements around the longitudinal axis. The succession patterns to generate the acceleration phases during these movements were described and statistically evaluated based on the onset time difference between the muscles of the corresponding muscle chain. In all the analyzed movement phases, the results clearly support the hypothesized succession pattern from punctum fixum to punctum mobile. This principle was further underlined by the finding that the succession patterns do change their direction running through the body when the rotational axis (punctum fixum) has been changed (e.g., high bar or rings [hands] vs. floor or trampoline [feet]). The findings improve our understanding of intersegmental neuromuscular coordination patterns to generate intentional movements most efficiently. This could help to develop more specific methods to facilitate such patterns in particular contexts, thus allowing for shorter motor learning procedures of context-specific key movement sequences in different disciplines of sports, as well as during non-sport specific movements. PMID:25822498

A novel nano-photonics biosensor concept for rapid molecular diagnostics

NASA Astrophysics Data System (ADS)

Klunder, Dion J. W.; van Herpen, Maarten M. J. W.; Kolesnychenko, Aleksey; Hornix, Eefje; Kahya, Nicoletta; de Boer, Ruth; Stapert, Henk

2008-04-01

We present a novel nano-photonics biosensor concept that offers an ultra-high surface specificity and excellent suppression of background signals due to the sample fluid on top of the biosensor. In our contribution, we will briefly discuss the operation principle and fabrication of the biosensor, followed by a more detailed discussion on the experimentally determined performance parameters. Recent results on detection of fluorescently labeled molecules in a highly fluorescent background will be shown, and we will give an outlook on real-time detection of bio-molecules such as proteins and nucleic acids.

RF Manipulation and Detection of Protons in the High Performance Antiproton Trap (HiPAT)

NASA Technical Reports Server (NTRS)

Martin, James J.; Lewis, Raymond A.; Pearson, J. Boise; Sims, W. Herb; Chakrabarti, Suman; Fant, Wallace E.; McDonald, Stan

2003-01-01

The significant energy density of matter-antimatter annihilation is attractive to the designers of future space propulsion systems, with the potential to offer a highly compact source of power. Many propulsion concepts exist that could take advantage of matter-antimatter reactions, and current antiproton production rates are sufficient to support basic proof-of-principle evaluation of technology associated with antimatter-derived propulsion. One enabling technology for such experiments is portable storage of low energy antiprotons, allowing antiprotons to be trapped, stored, and transported for use at an experimental facility.

The ultra high resolution XUV spectroheliograph: An attached payload for the Space Station Freedom

NASA Technical Reports Server (NTRS)

Walker, Arthur B. C., Jr.; Hoover, Richard B.; Barbee, Troy W., Jr.; Tandberg-Hanssen, Einar; Timothy, J. Gethyn; Lindblom, Joakim F.

1990-01-01

The principle goal of the ultra high resolution XUV spectroheliograph (UHRXS) is to improve the ability to identify and understand the fundamental physical processes that shape the structure and dynamics of the solar chromosphere and corona. The ability of the UHRXS imaging telescope and spectrographs to resolve fine scale structures over a broad wavelength (and hence temperature) range is critical to this mission. The scientific objectives and instrumental capabilities of the UHRXS investigation are reviewed before proceeding to a discussion of the expected performance of the UHRXS observatory.

Capacitively-coupled inductive sensors for measurements of pulsed currents and pulsed magnetic fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ekdahl, C.A.

In experiments involving pulsed high magnetic fields the appearance of the full induced voltage at the output terminals of large-area inductive sensors such as diamagnetic loops and Rogowski belts imposes severe requirements on the insulation near the output. Capacitive detection of the inductive-sensor output voltage provides an ideal geometry for high-voltage insulation, and also accomplishes the necessary voltage division. An inductive-shunt current monitor was designed to utilize the capacitive-detection principle. The contruction of this device and its performance are described in this paper.

Electronic structure and thermoelectric performance of Zintl compound Sr{sub 3}GaSb{sub 3}: A first-principles study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng Shi, Qing; Li Yan, Yu; Xu Wang, Yuan, E-mail: wangyx@henu.edu.cn

2014-01-06

By using first-principles method and Boltzmann theory, we simulated the thermoelectric transport properties of p-type and n-type Sr{sub 3}GaSb{sub 3}. It is found that the thermoelectric figure-of merit (ZT) of n-type Sr{sub 3}GaSb{sub 3} is probably better than that of p-type, mainly due to its large band degeneracy. Moreover, a high ZT value of 1.74 at 850 K can be achieved for n-type Sr{sub 3}GaSb{sub 3} along the yy direction, corresponding to the carrier concentration 3.5 × 10{sup 20} e cm{sup −3}. We propose that the high ZT value of experimentally synthesized p-type Sr{sub 3}GaSb{sub 3} is originated from appearing of the larger numbermore » of band valley on the top of valence bands.« less

[The principle and application of the single-molecule real-time sequencing technology].

PubMed

Yanhu, Liu; Lu, Wang; Li, Yu

2015-03-01

Last decade witnessed the explosive development of the third-generation sequencing strategy, including single-molecule real-time sequencing (SMRT), true single-molecule sequencing (tSMSTM) and the single-molecule nanopore DNA sequencing. In this review, we summarize the principle, performance and application of the SMRT sequencing technology. Compared with the traditional Sanger method and the next-generation sequencing (NGS) technologies, the SMRT approach has several advantages, including long read length, high speed, PCR-free and the capability of direct detection of epigenetic modifications. However, the disadvantage of its low accuracy, most of which resulted from insertions and deletions, is also notable. So, the raw sequence data need to be corrected before assembly. Up to now, the SMRT is a good fit for applications in the de novo genomic sequencing and the high-quality assemblies of small genomes. In the future, it is expected to play an important role in epigenetics, transcriptomic sequencing, and assemblies of large genomes.

Defense Innovation Unit Experimental (DIUX): Innovative or Excessive

DTIC Science & Technology

2017-04-06

DIUx, and the short history of DIUx. Innovation principles from authors Vijay Govindarajan, Michael Docherty, and Clayton Christensen are then...innovation principles such as performance engine & innovative team, collective / open innovation, and disruptive technology and its implications – is...various innovation principles drawing primarily from work by authors Vijay Govindarajan and Chris Trimble, Michael Docherty, and Clayton Christenson

RF MEMS microswitches design and characterization

NASA Astrophysics Data System (ADS)

Lafontan, Xavier; Dufaza, Christian; Robert, Michel; Perez, Guy; Pressecq, Francis

2000-08-01

This paper presents the work performed in MUMPs on RF MEMS micro-switch. Concepts, design and characterization of switches are studied. The study particularly focuses on the electrical resistance characterization and modelization. The switches developed uses two different principle: overflowed gold and hinged beam. The realized contacts exhibited high on resistance (~20(Omega) ) due to nanoscopics asperities of contacts and insulating interfacial films. Results of a typical contact cleaning method are also presented.

Clinical ophthalmic ultrasound improvements

NASA Technical Reports Server (NTRS)

Garrison, J. B.; Piro, P. A.

1981-01-01

The use of digital synthetic aperture techniques to obtain high resolution ultrasound images of eye and orbit was proposed. The parameters of the switched array configuration to reduce data collection time to a few milliseconds to avoid eye motion problems in the eye itself were established. An assessment of the effects of eye motion on the performance of the system was obtained. The principles of synthetic techniques are discussed. Likely applications are considered.

Predictions of Crystal Structures from First Principles

DTIC Science & Technology

2007-06-01

RDX crystal in hoped that the problem could be resolved by the molecular dynamics simulations . The fully ab initio development of density functional... Molecular Dynamics Simulations of RDX i.e., without any use of experimental results (except that Crystal the geometry of monomers was derived from X-ray...applied in molecular dynamics simulations of the RDX system, due to its size, is intractable by any high-level ab crystal. We performed isothermal

First-principles study of hole polaron formation and migration in SrI2

NASA Astrophysics Data System (ADS)

Zhou, Fei; Sadigh, Babak; Aberg, Daniel

2015-03-01

We investigate the formation of self-trapped holes (STH) in the high performance scintillator material SrI2 using a recently developed first principles method, polaron self-interaction correction (pSIC). pSIC removes the significant spurious self-interaction of localized polaron states. It is capable of accurately reproduce the configurational energy landscape of polaronic states from optimized hybrid functionals at the computational cost of the local density approximation. We searched for and identified all symmetrically distinct STH states localized on neighboring I-I dimers, i.e. Vk centers, and found non-trivial relation between the STH formation energies and dimer separation. All possible polaron hopping paths of the type IAIB -->IBIC are investigated systematically with pSIC and the elastic band method, and paths with low migration barrier energy of about 0.2 eV were identified, suggesting high mobility in SrI2. We expect that the present approach can be applied to study polaron formation and migration in other materials. Support from the National Nuclear Security Administration Office of Nonproliferation Research and Development (NA-22) is acknowledged. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore N We acknowledge funding from the NA-22 agency.

First principles Study on Transparent High-Tc Superconductivity in hole-doped Delafossite CuAlO2

NASA Astrophysics Data System (ADS)

Nakanishi, Akitaka; Katayama-Yoshida, Hiroshi

2012-02-01

The CuAlO2 is the transparent p-type conductor without any intentional doping. Transparent superdoncutivity and high thermoelectric power are suggested in p-type CuAlO2 [1]. Katayama-Yoshida et al. proposed that it may cause a strong electron-phonon interaction and a superconductivity. But, the calculation of superconducting critical temperature Tc is not performed. We performed the first principles calculation about the Tc of hole-doped CuAlO2 by shifting the Fermi level rigidly. In lightly hole-doped CuAlO2, the Fermi level is located at Cu and O anti-bonding band. The electrons of this band strongly interact with the A1L1 phonon mode because the direction of O-Cu-O dumbbell is parallel to the oscillation direction of the A1L1 phonon mode. As a result, Tc of lightly hole-doped CuAlO2 is about 50 K. We also discuss the materials design to enhance the Tc based on the charge-excitation-induced negative effective U system.[4pt] [1] H. Katayama-Yoshida, T. Koyanagi, H. Funashima, H. Harima, A. Yanase: Solid State Communication 126 (2003) 135. [0pt] [2] A. Nakanishi and H. Katayama-Yoshida: Solid State Communication, in printing. (arXiv:1107.2477v3

Principle of the electrically induced Transient Current Technique

NASA Astrophysics Data System (ADS)

Bronuzzi, J.; Moll, M.; Bouvet, D.; Mapelli, A.; Sallese, J. M.

2018-05-01

In the field of detector development for High Energy Physics, the so-called Transient Current Technique (TCT) is used to characterize the electric field profile and the charge trapping inside silicon radiation detectors where particles or photons create electron-hole pairs in the bulk of a semiconductor device, as PiN diodes. In the standard approach, the TCT signal originates from the free carriers generated close to the surface of a silicon detector, by short pulses of light or by alpha particles. This work proposes a new principle of charge injection by means of lateral PN junctions implemented in one of the detector electrodes, called the electrical TCT (el-TCT). This technique is fully compatible with CMOS technology and therefore opens new perspectives for assessment of radiation detectors performances.

Structure-induced asymmetry between counterpropagating modes and the reciprocity principle in whistle-geometry ring lasers

NASA Astrophysics Data System (ADS)

Osiński, Marek; Kalagara, Hemashilpa; Lee, Hosuk; Smolyakov, Gennady A.

2017-08-01

Greatly enhanced high-speed modulation performance has been recently predicted in numerical calculations for a novel injection-locking scheme involving a distributed Bragg reflector master laser monolithically integrated with a unidirectional whistle-geometry semiconductor microring laser. Operation of these devices relies on the assumption of large difference between modal losses experienced by counterpropagating modes. In this work, we confirm the unidirectionality of the whistle-geometry configuration through rigorous three-dimensional finite-difference timedomain (FDTD) simulation by showing a strong asymmetry in photon lifetimes between the two counterpropagating modes. We also show that similar asymmetry occurs in three-port couplers, whose structure resembles the coupling section of whistle-geometry lasers. We explain why these results do not violate the Helmholtz reciprocity principle.

Advanced characterization of lithium battery materials with positrons

NASA Astrophysics Data System (ADS)

Barbiellini, Bernardo; Kuriplach, Jan

2017-01-01

Cathode materials are crucial to improved battery performance, in part because there are not yet materials that can maintain high power and stable cycling with a capacity comparable to that of anode materials. Our parameter-free, gradient-corrected model for electron-positron correlations predicts that spectroscopies based on positron annihilation can be deployed to study the effect of lithium intercalation in the oxide matrix of the cathode. The positron characteristics in oxides can be reliably computed using methods based on first-principles. Thus, we can enable a fundamental characterization of lithium battery materials involving positron annihilation spectroscopy and first-principles calculations. The detailed information one can extract from positron experiments could be useful for understanding and optimizing both battery materials and bi-functional catalysts for oxygen reduction and evolution.

Ultrasmooth Perovskite Film via Mixed Anti-Solvent Strategy with Improved Efficiency.

PubMed

Yu, Yu; Yang, Songwang; Lei, Lei; Cao, Qipeng; Shao, Jun; Zhang, Sheng; Liu, Yan

2017-02-01

Most antisolvents employed in previous research were miscible with perovskite precursor solution. They always led to fast formation of perovskite even if the intermediate stage existed, which was not beneficial to obtain high quality perovskite films and made the formation process less controllable. In this work, a novel ethyl ether/n-hexane mixed antisolvent (MAS) was used to achieve high nucleation density and slow down the formation process of perovskite, producing films with improved orientation of grains and ultrasmooth surfaces. These high quality films exhibited efficient charge transport at the interface of perovskite/hole transport material and perovskite solar cells based on these films showed greatly improved performance with the best power conversion efficiency of 17.08%. This work also proposed a selection principle of MAS and showed that solvent engineering by designing the mixed antisolvent system can lead to the fabrication of high-performance perovskite solar cells.

Gaseous Electron Multiplier (GEM) Detectors

NASA Astrophysics Data System (ADS)

Gnanvo, Kondo

2017-09-01

Gaseous detectors have played a pivotal role as tracking devices in the field of particle physics experiments for the last fifty years. Recent advances in photolithography and micro processing techniques have enabled the transition from Multi Wire Proportional Chambers (MWPCs) and Drift Chambers to a new family of gaseous detectors refer to as Micro Pattern Gaseous Detectors (MPGDs). MPGDs combine the basic gas amplification principle with micro-structure printed circuits to provide detectors with excellent spatial and time resolution, high rate capability, low material budget and high radiation tolerance. Gas Electron Multiplier (GEMs) is a well-established MPGD technology invented by F. Sauli at CERN in 1997 and deployed various high energy physics (HEP) and nuclear NP experiment for tracking systems of current and future NP experiments. GEM detector combines an exceptional high rate capability (1 MHz / mm2) and robustness against harsh radiation environment with excellent position and timing resolution performances. Recent breakthroughs over the past decade have allowed the possibility for large area GEMs, making them cost effective and high-performance detector candidates to play pivotal role in current and future particle physics experiments. After a brief introduction of the basic principle of GEM technology, I will give a brief overview of the GEM detectors used in particle physics experiments over the past decades and especially in the NP community at Thomas Jefferson National Laboratory (JLab) and Brookhaven National Laboratory (BNL). I will follow by a review of state of the art of the new GEM development for the next generation of colliders such as Electron Ion Collider (EIC) or High Luminosity LHC and future Nuclear Physics experiments. I will conclude with a presentation of the CERN-based RD51 collaboration established in 2008 and its major achievements regarding technological developments and applications of MPGDs.

A homemade high-resolution orthogonal-injection time-of-flight mass spectrometer with a heated capillary inlet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo Changjuan; Huang Zhengxu; Gao Wei

2008-01-15

We describe a homemade high-resolution orthogonal-injection time-of-flight (O-TOF) mass spectrometer combing a heated capillary inlet. The O-TOF uses a heated capillary tube combined with a radio-frequency only quadrupole (rf-only quadrupole) as an interface to help the ion transmission from the atmospheric pressure to the low-pressure regions. The principle, configuration of the O-TOF, and the performance of the instrument are introduced in this paper. With electrospray ion source, the performances of the mass resolution, the sensitivity, the mass range, and the mass accuracy are described. We also include our results obtained by coupling atmospheric pressure matrix-assisted laser deporption ionization with thismore » instrument.« less

High-performance computing with quantum processing units

DOE PAGES

Britt, Keith A.; Oak Ridge National Lab.; Humble, Travis S.; ...

2017-03-01

The prospects of quantum computing have driven efforts to realize fully functional quantum processing units (QPUs). Recent success in developing proof-of-principle QPUs has prompted the question of how to integrate these emerging processors into modern high-performance computing (HPC) systems. We examine how QPUs can be integrated into current and future HPC system architectures by accounting for func- tional and physical design requirements. We identify two integration pathways that are differentiated by infrastructure constraints on the QPU and the use cases expected for the HPC system. This includes a tight integration that assumes infrastructure bottlenecks can be overcome as well asmore » a loose integration that as- sumes they cannot. We find that the performance of both approaches is likely to depend on the quantum interconnect that serves to entangle multiple QPUs. As a result, we also identify several challenges in assessing QPU performance for HPC, and we consider new metrics that capture the interplay between system architecture and the quantum parallelism underlying computational performance.« less

High-performance computing with quantum processing units

DOE Office of Scientific and Technical Information (OSTI.GOV)

Britt, Keith A.; Oak Ridge National Lab.; Humble, Travis S.

The prospects of quantum computing have driven efforts to realize fully functional quantum processing units (QPUs). Recent success in developing proof-of-principle QPUs has prompted the question of how to integrate these emerging processors into modern high-performance computing (HPC) systems. We examine how QPUs can be integrated into current and future HPC system architectures by accounting for func- tional and physical design requirements. We identify two integration pathways that are differentiated by infrastructure constraints on the QPU and the use cases expected for the HPC system. This includes a tight integration that assumes infrastructure bottlenecks can be overcome as well asmore » a loose integration that as- sumes they cannot. We find that the performance of both approaches is likely to depend on the quantum interconnect that serves to entangle multiple QPUs. As a result, we also identify several challenges in assessing QPU performance for HPC, and we consider new metrics that capture the interplay between system architecture and the quantum parallelism underlying computational performance.« less

Numerical investigation of design and operation parameters on CHI spheromak performance

NASA Astrophysics Data System (ADS)

O'Bryan, J. B.; Romero-Talamás, C. R.; Woodruff, S.

2017-10-01

Nonlinear, numerical computation with the NIMROD code is used to explore magnetic self-organization in spheromaks formed with coaxial helicity injection, particularly with regard to how externally controllable parameters affect the resulting spheromak performance. The overall goal of our study is to inform the design and operational parameters of a future proof-of-principle spheromak experiment. Our calculations start from vacuum magnetic fields and model multiple distinct phases of evolution. Results indicate that modest changes to the design and operation of past experiments, e.g. SSPX [E.B. Hooper et al. PPCF 2012], could have significantly improved the plasma-current injector coupling efficiency and performance, particularly with respect to peak temperature and lifetime. While we frequently characterize performance relative to SSPX, our conclusions extrapolate to fundamentally different experimental designs. We also explore adiabatic magnetic compression of spheromaks, which may allow for a small-scale, high-performance and high-yield pulsed neutron source. This work is supported by DAPRA under Grant No. N66001-14-1-4044.

In Search of Design Principles for Developing Digital Learning and Performance Support for a Student Design Task

ERIC Educational Resources Information Center

Bollen, Lars; van der Meij, Hans; Leemkuil, Henny; McKenney, Susan

2015-01-01

A digital learning and performance support environment for university student design tasks was developed. This paper describes on the design rationale, process, and the usage results to arrive at a core set of design principles for the construction of such an environment. We present a collection of organizational, technical, and course-related…

Did recent world record marathon runners employ optimal pacing strategies?

PubMed

Angus, Simon D

2014-01-01

We apply statistical analysis of high frequency (1 km) split data for the most recent two world-record marathon runs: Run 1 (2:03:59, 28 September 2008) and Run 2 (2:03:38, 25 September 2011). Based on studies in the endurance cycling literature, we develop two principles to approximate 'optimal' pacing in the field marathon. By utilising GPS and weather data, we test, and then de-trend, for each athlete's field response to gradient and headwind on course, recovering standardised proxies for power-based pacing traces. The resultant traces were analysed to ascertain if either runner followed optimal pacing principles; and characterise any deviations from optimality. Whereas gradient was insignificant, headwind was a significant factor in running speed variability for both runners, with Runner 2 targeting the (optimal) parallel variation principle, whilst Runner 1 did not. After adjusting for these responses, neither runner followed the (optimal) 'even' power pacing principle, with Runner 2's macro-pacing strategy fitting a sinusoidal oscillator with exponentially expanding envelope whilst Runner 1 followed a U-shaped, quadratic form. The study suggests that: (a) better pacing strategy could provide elite marathon runners with an economical pathway to significant performance improvements at world-record level; and (b) the data and analysis herein is consistent with a complex-adaptive model of power regulation.

A review on ab initio studies of static, transport, and optical properties of polystyrene under extreme conditions for inertial confinement fusion applications

NASA Astrophysics Data System (ADS)

Hu, S. X.; Collins, L. A.; Boehly, T. R.; Ding, Y. H.; Radha, P. B.; Goncharov, V. N.; Karasiev, V. V.; Collins, G. W.; Regan, S. P.; Campbell, E. M.

2018-05-01

Polystyrene (CH), commonly known as "plastic," has been one of the widely used ablator materials for capsule designs in inertial confinement fusion (ICF). Knowing its precise properties under high-energy-density conditions is crucial to understanding and designing ICF implosions through radiation-hydrodynamic simulations. For this purpose, systematic ab initio studies on the static, transport, and optical properties of CH, in a wide range of density and temperature conditions (ρ = 0.1 to 100 g/cm3 and T = 103 to 4 × 106 K), have been conducted using quantum molecular dynamics (QMD) simulations based on the density functional theory. We have built several wide-ranging, self-consistent material-properties tables for CH, such as the first-principles equation of state, the QMD-based thermal conductivity (κQMD) and ionization, and the first-principles opacity table. This paper is devoted to providing a review on (1) what results were obtained from these systematic ab initio studies; (2) how these self-consistent results were compared with both traditional plasma-physics models and available experiments; and (3) how these first-principles-based properties of polystyrene affect the predictions of ICF target performance, through both 1-D and 2-D radiation-hydrodynamic simulations. In the warm dense regime, our ab initio results, which can significantly differ from predictions of traditional plasma-physics models, compared favorably with experiments. When incorporated into hydrocodes for ICF simulations, these first-principles material properties of CH have produced significant differences over traditional models in predicting 1-D/2-D target performance of ICF implosions on OMEGA and direct-drive-ignition designs for the National Ignition Facility. Finally, we will discuss the implications of these studies on the current small-margin ICF target designs using a CH ablator.

Bi-directional series-parallel elastic actuator and overlap of the actuation layers.

PubMed

Furnémont, Raphaël; Mathijssen, Glenn; Verstraten, Tom; Lefeber, Dirk; Vanderborght, Bram

2016-01-27

Several robotics applications require high torque-to-weight ratio and energy efficient actuators. Progress in that direction was made by introducing compliant elements into the actuation. A large variety of actuators were developed such as series elastic actuators (SEAs), variable stiffness actuators and parallel elastic actuators (PEAs). SEAs can reduce the peak power while PEAs can reduce the torque requirement on the motor. Nonetheless, these actuators still cannot meet performances close to humans. To combine both advantages, the series parallel elastic actuator (SPEA) was developed. The principle is inspired from biological muscles. Muscles are composed of motor units, placed in parallel, which are variably recruited as the required effort increases. This biological principle is exploited in the SPEA, where springs (layers), placed in parallel, can be recruited one by one. This recruitment is performed by an intermittent mechanism. This paper presents the development of a SPEA using the MACCEPA principle with a self-closing mechanism. This actuator can deliver a bi-directional output torque, variable stiffness and reduced friction. The load on the motor can also be reduced, leading to a lower power consumption. The variable recruitment of the parallel springs can also be tuned in order to further decrease the consumption of the actuator for a given task. First, an explanation of the concept and a brief description of the prior work done will be given. Next, the design and the model of one of the layers will be presented. The working principle of the full actuator will then be given. At the end of this paper, experiments showing the electric consumption of the actuator will display the advantage of the SPEA over an equivalent stiff actuator.

[History of ureteropelvic junction obstruction repair (pyeloplasty). From Trendelenburg (1886) to the present].

PubMed

Poulakis, V; Witzsch, U; Schultheiss, D; Rathert, P; Becht, E

2004-12-01

The first reconstructive procedure for ureteropelvic junction (UPJ) obstruction was performed by Trendelenburg in 1886. The important milestones in the reconstruction of UPJ are discussed and all available historical papers and reports since 1886 are reviewed. Kuster published the first successful dismembered pyeloplasty 5 years later, but his technique was prone to strictures. In 1892, the application of the Heineke-Mickulicz principle by Fenger resulted in bulking and kinking with obstruction. Plication of the renal pelvis, first introduced by Israel in 1896, was modified by Kelly in 1906. After the principle of the Finney pyloroplasty, von Lichtenberg designed his pyeloplasty in 1921, best suited to cases of high implantation of the ureter. Foley modified flap techniques, first introduced by Schwyzer in 1923 after the application of the Durante pyloroplasty principle, successfully to Y-V pyeloplasty in 1937. Culp and de-Weerd introduced the spiral flap in 1951. Scardino and Prince reported about the vertical flap in 1953. Patel published the extra-long spiral flap technique in 1982. In order to decrease the likelihood of stricture, Nesbit, in 1949, modified Kuster's procedure by utilizing an elliptic anastomosis. In the same year, Anderson and Hynes, published their technique. With the advent of endourology, several minimally invasive procedures were applied: antegrade or retrograde endopyelotomy, balloon dilation, and laparoscopic pyeloplasty. The concept of full-thickness incision of the narrow segment followed by prolonged stenting was first described in 1903 by Albarran and was popularized by Davis in 1943. Several basic principles must be applied in order to ensure successful repair: the resultant anastomosis should be widely patent, performed in a watertight fashion without tension. Endopyelotomy represents an alternative to open surgery.

Physics-based approach to chemical source localization using mobile robotic swarms

NASA Astrophysics Data System (ADS)

Zarzhitsky, Dimitri

2008-07-01

Recently, distributed computation has assumed a dominant role in the fields of artificial intelligence and robotics. To improve system performance, engineers are combining multiple cooperating robots into cohesive collectives called swarms. This thesis illustrates the application of basic principles of physicomimetics, or physics-based design, to swarm robotic systems. Such principles include decentralized control, short-range sensing and low power consumption. We show how the application of these principles to robotic swarms results in highly scalable, robust, and adaptive multi-robot systems. The emergence of these valuable properties can be predicted with the help of well-developed theoretical methods. In this research effort, we have designed and constructed a distributed physicomimetics system for locating sources of airborne chemical plumes. This task, called chemical plume tracing (CPT), is receiving a great deal of attention due to persistent homeland security threats. For this thesis, we have created a novel CPT algorithm called fluxotaxis that is based on theoretical principles of fluid dynamics. Analytically, we show that fluxotaxis combines the essence, as well as the strengths, of the two most popular biologically-inspired CPT methods-- chemotaxis and anemotaxis. The chemotaxis strategy consists of navigating in the direction of the chemical density gradient within the plume, while the anemotaxis approach is based on an upwind traversal of the chemical cloud. Rigorous and extensive experimental evaluations have been performed in simulated chemical plume environments. Using a suite of performance metrics that capture the salient aspects of swarm-specific behavior, we have been able to evaluate and compare the three CPT algorithms. We demonstrate the improved performance of our fluxotaxis approach over both chemotaxis and anemotaxis in these realistic simulation environments, which include obstacles. To test our understanding of CPT on actual hardware, we have implemented chemotaxis on three laboratory-scale robots. Chemotaxis requires only chemical sensors; eventually, when small-scale anemometers capable of reliably detecting low air velocities become available, we plan to implement anemotaxis and fluxotaxis on the robots as well. Our chemotaxis robots use the physicomimetics control algorithm to arrange the team of vehicles into a triangular formation, which then traces an ethanol vapor plume to its source emitter. In agreement with our theoretical predictions, the swarm implementation shows a consistent gain in CPT performance as compared to a single-robot solution.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faizal, Mir, E-mail: f2mir@uwaterloo.ca; Majumder, Barun, E-mail: barunbasanta@iitgn.ac.in

In this paper, we will incorporate the generalized uncertainty principle into field theories with Lifshitz scaling. We will first construct both bosonic and fermionic theories with Lifshitz scaling based on generalized uncertainty principle. After that we will incorporate the generalized uncertainty principle into a non-abelian gauge theory with Lifshitz scaling. We will observe that even though the action for this theory is non-local, it is invariant under local gauge transformations. We will also perform the stochastic quantization of this Lifshitz fermionic theory based generalized uncertainty principle.

Simulation-based crisis resource management training for pediatric critical care medicine: a review for instructors.

PubMed

Cheng, Adam; Donoghue, Aaron; Gilfoyle, Elaine; Eppich, Walter

2012-03-01

To review the essential elements of crisis resource management and provide a resource for instructors by describing how to use simulation-based training to teach crisis resource management principles in pediatric acute care contexts. A MEDLINE-based literature source. OUTLINE OF REVIEW: This review is divided into three main sections: Background, Principles of Crisis Resource Management, and Tools and Resources. The background section provides the brief history and definition of crisis resource management. The next section describes all the essential elements of crisis resource management, including leadership and followership, communication, teamwork, resource use, and situational awareness. This is followed by a review of evidence supporting the use of simulation-based crisis resource management training in health care. The last section provides the resources necessary to develop crisis resource management training using a simulation-based approach. This includes a description of how to design pediatric simulation scenarios, how to effectively debrief, and a list of potential assessment tools that instructors can use to evaluate crisis resource management performance during simulation-based training. Crisis resource management principles form the foundation for efficient team functioning and subsequent error reduction in high-stakes environments such as acute care pediatrics. Effective instructor training is required for those programs wishing to teach these principles using simulation-based learning. Dissemination and integration of these principles into pediatric critical care practice has the potential for a tremendous impact on patient safety and outcomes.

78 FR 44627 - HOME Investment Partnerships Program: Improving Performance and Accountability; Updating Property...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-24

... (Faith-Based Activities) to reflect the amendments made by Executive Order 13559 (Fundamental Principles... several important values and principles of community development. First, the HOME program's flexibility is...

Use of an approximate similarity principle for the thermal scaling of a full-scale thrust augmenting ejector

NASA Technical Reports Server (NTRS)

Barankiewicz, Wendy S.; Perusek, Gail P.; Ibrahim, Mounir B.

1992-01-01

Full temperature ejector model simulations are expensive, and difficult to implement experimentally. If an approximate similarity principle could be established, properly chosen performance parameters should be similar for both hot and cold flow tests if the initial Mach number and total pressures of the flow field are held constant. Existing ejector data is used to explore the utility of one particular similarity principle; the Munk and Prim similarity principle for isentropic flows. Static performance test data for a full-scale thrust augmenting ejector are analyzed for primary flow temperatures up to 1560 R. At different primary temperatures, exit pressure contours are compared for similarity. A nondimensional flow parameter is then used to eliminate primary nozzle temperature dependence and verify similarity between the hot and cold flow experiments.

Use of an approximate similarity principle for the thermal scaling of a full-scale thrust augmenting ejector

NASA Technical Reports Server (NTRS)

Barankiewicz, Wendy; Perusek, Gail P.; Ibrahim, Mounir

1992-01-01

Full temperature ejector model simulations are expensive, and difficult to implement experimentally. If an approximate similarity principle could be established, properly chosen performance parameters should be similar for both hot and cold flow tests if the initial Mach number and total pressures of the flow field are held constant. Existing ejector data is used to explore the utility of one particular similarity principle; the Munk and Prim similarity principle for isentropic flows. Static performance test data for a full-scale thrust augmenting ejector are analyzed for primary flow temperatures up to 1560 R. At different primary temperatures, exit pressure contours are compared for similarity. A nondimensional flow paramenter is then used to eliminate primary nozzle temperature dependence and verify similarity between the hot and cold flow experiments.

Using a Simple Neural Network to Delineate Some Principles of Distributed Economic Choice.

PubMed

Balasubramani, Pragathi P; Moreno-Bote, Rubén; Hayden, Benjamin Y

2018-01-01

The brain uses a mixture of distributed and modular organization to perform computations and generate appropriate actions. While the principles under which the brain might perform computations using modular systems have been more amenable to modeling, the principles by which the brain might make choices using distributed principles have not been explored. Our goal in this perspective is to delineate some of those distributed principles using a neural network method and use its results as a lens through which to reconsider some previously published neurophysiological data. To allow for direct comparison with our own data, we trained the neural network to perform binary risky choices. We find that value correlates are ubiquitous and are always accompanied by non-value information, including spatial information (i.e., no pure value signals). Evaluation, comparison, and selection were not distinct processes; indeed, value signals even in the earliest stages contributed directly, albeit weakly, to action selection. There was no place, other than at the level of action selection, at which dimensions were fully integrated. No units were specialized for specific offers; rather, all units encoded the values of both offers in an anti-correlated format, thus contributing to comparison. Individual network layers corresponded to stages in a continuous rotation from input to output space rather than to functionally distinct modules. While our network is likely to not be a direct reflection of brain processes, we propose that these principles should serve as hypotheses to be tested and evaluated for future studies.

Using a Simple Neural Network to Delineate Some Principles of Distributed Economic Choice

PubMed Central

Balasubramani, Pragathi P.; Moreno-Bote, Rubén; Hayden, Benjamin Y.

2018-01-01

The brain uses a mixture of distributed and modular organization to perform computations and generate appropriate actions. While the principles under which the brain might perform computations using modular systems have been more amenable to modeling, the principles by which the brain might make choices using distributed principles have not been explored. Our goal in this perspective is to delineate some of those distributed principles using a neural network method and use its results as a lens through which to reconsider some previously published neurophysiological data. To allow for direct comparison with our own data, we trained the neural network to perform binary risky choices. We find that value correlates are ubiquitous and are always accompanied by non-value information, including spatial information (i.e., no pure value signals). Evaluation, comparison, and selection were not distinct processes; indeed, value signals even in the earliest stages contributed directly, albeit weakly, to action selection. There was no place, other than at the level of action selection, at which dimensions were fully integrated. No units were specialized for specific offers; rather, all units encoded the values of both offers in an anti-correlated format, thus contributing to comparison. Individual network layers corresponded to stages in a continuous rotation from input to output space rather than to functionally distinct modules. While our network is likely to not be a direct reflection of brain processes, we propose that these principles should serve as hypotheses to be tested and evaluated for future studies. PMID:29643773

Objective Diagnosis of Cervical Cancer by Tissue Protein Profile Analysis

NASA Astrophysics Data System (ADS)

Patil, Ajeetkumar; Bhat, Sujatha; Rai, Lavanya; Kartha, V. B.; Chidangil, Santhosh

2011-07-01

Protein profiles of homogenized normal cervical tissue samples from hysterectomy subjects and cancerous cervical tissues from biopsy samples collected from patients with different stages of cervical cancer were recorded using High Performance Liquid Chromatography coupled with Laser Induced Fluorescence (HPLC-LIF). The Protein profiles were subjected to Principle Component Analysis to derive statistically significant parameters. Diagnosis of sample types were carried out by matching three parameters—scores of factors, squared residuals, and Mahalanobis Distance. ROC and Youden's Index curves for calibration standards were used for objective estimation of the optimum threshold for decision making and performance.

Model Error Budgets

NASA Technical Reports Server (NTRS)

Briggs, Hugh C.

2008-01-01

An error budget is a commonly used tool in design of complex aerospace systems. It represents system performance requirements in terms of allowable errors and flows these down through a hierarchical structure to lower assemblies and components. The requirements may simply be 'allocated' based upon heuristics or experience, or they may be designed through use of physics-based models. This paper presents a basis for developing an error budget for models of the system, as opposed to the system itself. The need for model error budgets arises when system models are a principle design agent as is increasingly more common for poorly testable high performance space systems.

Standing wave performance test of IDT-SAW transducer prepared by silk-screen printing

NASA Astrophysics Data System (ADS)

Wang, Ziping; Jiang, Zhengxuan; Chen, Liangbin; Li, Yefei; Li, Meixia; Wang, Shaohan

2018-05-01

With the advantages of high performance and low loss, interdigital surface acoustic wave (IDT-SAW) transducers are widely used in the fields of nondestructive testing, communication and broadcasting. The production, performance and application of surface acoustic wave (SAW) actuators has become a research hotspot. Based on the basic principle of SAW, an IDT-SAW transducer is designed and fabricated using silk-screen printing in this work. The experiment results show that in terms of SAW performance, the fabricated IDT-SAW transducer can generate standing wave fields comparable to those generated using traditional fabrication methods. The resonant frequency response of the IDT-SAW transducer and SAW attenuation coefficient were obtained by experiments. It has provided a method to test the transducer sensing performance by using fabricated IDT-SAW transducer.

Review of cell performance in anion exchange membrane fuel cells

NASA Astrophysics Data System (ADS)

Dekel, Dario R.

2018-01-01

Anion exchange membrane fuel cells (AEMFCs) have recently received increasing attention since in principle they allow for the use of non-precious metal catalysts, which dramatically reduces the cost per kilowatt of power in fuel cell devices. Until not long ago, the main barrier in the development of AEMFCs was the availability of highly conductive anion exchange membranes (AEMs); however, improvements on this front in the past decade show that newly developed AEMs have already reached high levels of conductivity, leading to satisfactory cell performance. In recent years, a growing number of research studies have reported AEMFC performance results. In the last three years, new records in performance were achieved. Most of the literature reporting cell performance is based on hydrogen-AEMFCs, although an increasing number of studies have also reported the use of fuels others than hydrogen - such as alcohols, non-alcohol C-based fuels, as well as N-based fuels. This article reviews the cell performance and performance stability achieved in AEMFCs through the years since the first reports in the early 2000s.

26 CFR 4.954-2 - Foreign personal holding company income; taxable years beginning after December 31, 1986.

Code of Federal Regulations, 2010 CFR

2010-04-01

...)(3). Except as otherwise provided under this paragraph (b)(3), the principles of section 367(a) and..., the determination of the country in which services are performed shall be made under the principles of... gross income derived by the payor) under the principles of § 1.861-8. (ix) Location of debt instruments...

Structures and magnetic properties of Co-Zr-B magnets studied by first-principles calculations

DOE PAGES

Zhao, Xin; Ke, Liqin; Nguyen, Manh Cuong; ...

2015-06-23

The structures and magnetic properties of Co-Zr-B alloys near the composition of Co 5Zr with B at. % ≤6% were studied using adaptive genetic algorithm and first-principles calculations. The energy and magnetic moment contour maps as a function of chemical composition were constructed for the Co-Zr-B magnet alloys through extensive structure searches and calculations. We found that Co-Zr-B system exhibits the same structure motif as the “Co 11Zr 2” polymorphs, and such motif plays a key role in achieving strong magnetic anisotropy. Boron atoms were found to be able to substitute cobalt atoms or occupy the “interruption” sites. First-principles calculationsmore » showed that the magnetocrystalline anisotropy energies of the boron-doped alloys are close to that of the high-temperature rhombohedral Co 5Zr phase and larger than that of the low-temperature Co 5.25Zr phase. As a result, our calculations provide useful guidelines for further experimental optimization of the magnetic performances of these alloys.« less

First-Principles Prediction of Thermodynamically Stable Two-Dimensional Electrides

DOE PAGES

Ming, Wenmei; Yoon, Mina; Univ. of Tennessee, Knoxville, TN; ...

2016-10-21

Two-dimensional (2D) electrides, emerging as a new type of layered material whose electrons are confined in interlayer spaces instead of at atomic proximities, are receiving interest for their high performance in various (opto)electronics and catalytic applications. Experimentally, however, 2D electrides have been only found in a couple of layered nitrides and carbides. We report new thermodynamically stable alkaline-earth based 2D electrides by using a first-principles global structure optimization method, phonon spectrum analysis, and molecular dynamics simulation. The method was applied to binary compounds consisting of alkaline-earth elements as cations and group VA, VIA, or VIIA nonmetal elements as anions. Wemore » also revealed that the stability of a layered 2D electride structure is closely related to the cation/anion size ratio; stable 2D electrides possess a sufficiently large cation/anion size ratio to minimize electrostatic energy among cations, anions, and anionic electrons. This work demonstrates a new avenue to the discovery of thermodynamically stable 2D electrides beyond experimental material databases and provides new insight into the principles of electride design.« less

Design And Demonstration Of Band-limited Hybrid Coronagraph Masks For Space Imaging And Spectroscopy Of Exoplanetary Systems

NASA Astrophysics Data System (ADS)

Trauger, John T.; Moody, D. C.

2010-05-01

Among the leading architectures for the imaging and spectroscopy of nearby exoplanetary systems is the space coronagraph, which provides in principle very high (10 billion to one) suppression of diffracted and scattered starlight at very small separations (a few tenths of arcseconds) from the star. The concept of a band-limited Lyot coronagraph, introduced by Kuchner and Traub (2002), provides the theoretical basis for mathematically perfect starlight suppression. In practice, the optical characteristics of available materials and practical aspects of the fabrication processes impose limitations on contrast and spectral bandwidths that are achievable in the real world. Nevertheless, the band-limited Lyot coronagraph approach has produced the best laboratory validated performance among known types of internal coronagraph for contrast and spectral bandwidth, and alone it has demonstrated high-contrast imaging performance at levels required for exoplanet exploration. We report the design and fabrication of hybrid focal-plane masks for Lyot coronagraphy, composed of thickness-profiled metallic and dielectric thin films, vacuum deposited on a glass substrate. These masks are in principle band-limited in both the real and imaginary parts of the complex amplitude characteristics. Together with a deformable mirror for control of wavefront phase, these masks have the potential for contrast performance better than 10-9 at inner working angles of 3 lambda/D or better over spectral bandwidths of 20% or more, and with throughput efficiencies up to 60%. We report recent laboratory demonstrations of high contrast with nickel-dielectric masks, including the demonstration of 2x10-9 contrast with a 3 lambda/D inner working angle over 20% spectral bandwidths.

Design of a prototype tri-electrode ion-chamber for megavoltage X-ray imaging

NASA Astrophysics Data System (ADS)

Samant, Sanjiv S.; Gopal, Arun; Jain, Jinesh; Xia, Junyi; DiBianca, Frank A.

2007-04-01

High-energy (megavoltage) X-ray imaging is widely used in industry (e.g., aerospace, construction, material sciences) as well as in health care (radiation therapy). One of the fundamental problems with megavoltage imaging is poor contrast and spatial resolution in the detected images due to the dominance of Compton scattering at megavoltage X-ray energies. Therefore, although megavoltage X-rays can be used to image highly attenuating objects that cannot be imaged at kilovoltage energies, the former does not provide the high image quality that is associated with the latter. A high contrast and spatial resolution detector for high-energy X-ray fields called the kinestatic charge detector (KCD) is presented here. The KCD is a tri-electrode ion-chamber based on highly pressurized noble gas. The KCD operates in conjunction with a strip-collimated X-ray beam (for high scatter rejection) to scan across the imaging field. Its thick detector design and unique operating principle provides enhanced charge signal integration for high quality imaging (quantum efficiency ˜50%) despite the unfavorable implications of high-energy X-ray interactions on image quality. The proposed design for a large-field prototype KCD includes a cylindrical pressure chamber along with 576 signal-collecting electrodes capable of resolving at 2 mm -1. The collecting electrodes are routed out of the chamber through the flat end-cap, thereby optimizing the mechanical strength of the chamber. This article highlights the simplified design of the chamber using minimal components for simple assembly. In addition, fundamental imaging measurements and estimates of ion recombination that were performed on a proof-of-principle test chamber are presented. The imaging performance of the prototype KCD was found to be an order-of-magnitude greater than commercial phosphor screen based flat-panel systems, demonstrating the potential for high-quality megavoltage imaging for a variety of industrial applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duro, Francisco Rodrigo; Blas, Javier Garcia; Isaila, Florin

The increasing volume of scientific data and the limited scalability and performance of storage systems are currently presenting a significant limitation for the productivity of the scientific workflows running on both high-performance computing (HPC) and cloud platforms. Clearly needed is better integration of storage systems and workflow engines to address this problem. This paper presents and evaluates a novel solution that leverages codesign principles for integrating Hercules—an in-memory data store—with a workflow management system. We consider four main aspects: workflow representation, task scheduling, task placement, and task termination. As a result, the experimental evaluation on both cloud and HPC systemsmore » demonstrates significant performance and scalability improvements over existing state-of-the-art approaches.« less

Design of high reliability organizations in health care

PubMed Central

Carroll, J S; Rudolph, J W

2006-01-01

To improve safety performance, many healthcare organizations have sought to emulate high reliability organizations from industries such as nuclear power, chemical processing, and military operations. We outline high reliability design principles for healthcare organizations including both the formal structures and the informal practices that complement those structures. A stage model of organizational structures and practices, moving from local autonomy to formal controls to open inquiry to deep self‐understanding, is used to illustrate typical challenges and design possibilities at each stage. We suggest how organizations can use the concepts and examples presented to increase their capacity to self‐design for safety and reliability. PMID:17142607

High-Performance Schools: Affordable Green Design for K-12 Schools; Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plympton, P.; Brown, J.; Stevens, K.

2004-08-01

Schools in the United States spend $7.8 billion on energy each year-more than the cost of computers and textbooks combined, according to a 2003 report from the National Center for Education Statistics. The U.S. Department of Energy (DOE) estimates that these high utility bills could be reduced as much as 25% if schools adopt readily available high performance design principles and technologies. Accordingly, hundreds of K-12 schools across the country have made a commitment to improve the learning and teaching environment of schools while saving money and energy and protecting the environment. DOE and its public- and private-sector partners havemore » developed Energy Design Guidelines for High Performance Schools, customized for nine climate zones in U.S. states and territories. These design guidelines provide information for school decision makers and design professionals on the advantages of energy efficiency and renewable energy designs and technologies. With such features as natural day lighting, efficient electric lights, water conservation, and renewable energy, schools in all types of climates are proving that school buildings, and the students and teachers who occupy them, are indeed high performers. This paper describes high performance schools from each of the nine climate zones associated with the Energy Design Guidelines. The nine case studies focus on the high performance design strategies implemented in each school, as well as the cost savings and benefits realized by students, faculty, the community, and the environment.« less

A biopolymer-like metal enabled hybrid material with exceptional mechanical prowess

DOE PAGES

Zhang, Junsong; Cui, Lishan; Jiang, Daqiang; ...

2015-02-10

In this study, the design principles for naturally occurring biological materials have inspired us to develop next-generation engineering materials with remarkable performance. Nacre, commonly referred to as nature's armor, is renowned for its unusual combination of strength and toughness. Nature's wisdom in nacre resides in its elaborate structural design and the judicious placement of a unique organic biopolymer with intelligent deformation features. However, up to now, it is still a challenge to transcribe the biopolymer's deformation attributes into a stronger substitute in the design of new materials. In this study, we propose a new design strategy that employs shape memorymore » alloy to transcribe the "J-curve'' mechanical response and uniform molecular/atomic level deformation of the organic biopolymer in the design of high-performance hybrid materials. This design strategy is verified in a TiNi-Ti 3Sn model material system. The model material demonstrates an exceptional combination of mechanical properties that are superior to other high-performance metal-based lamellar composites known to date. Our design strategy creates new opportunities for the development of high-performance bio-inspired materials.« less

A biopolymer-like metal enabled hybrid material with exceptional mechanical prowess

PubMed Central

Zhang, Junsong; Cui, Lishan; Jiang, Daqiang; Liu, Yinong; Hao, Shijie; Ren, Yang; Han, Xiaodong; Liu, Zhenyang; Wang, Yunzhi; Yu, Cun; Huan, Yong; Zhao, Xinqing; Zheng, Yanjun; Xu, Huibin; Ren, Xiaobing; Li, Xiaodong

2015-01-01

The design principles for naturally occurring biological materials have inspired us to develop next-generation engineering materials with remarkable performance. Nacre, commonly referred to as nature's armor, is renowned for its unusual combination of strength and toughness. Nature's wisdom in nacre resides in its elaborate structural design and the judicious placement of a unique organic biopolymer with intelligent deformation features. However, up to now, it is still a challenge to transcribe the biopolymer's deformation attributes into a stronger substitute in the design of new materials. In this study, we propose a new design strategy that employs shape memory alloy to transcribe the “J-curve” mechanical response and uniform molecular/atomic level deformation of the organic biopolymer in the design of high-performance hybrid materials. This design strategy is verified in a TiNi-Ti3Sn model material system. The model material demonstrates an exceptional combination of mechanical properties that are superior to other high-performance metal-based lamellar composites known to date. Our design strategy creates new opportunities for the development of high-performance bio-inspired materials. PMID:25665501

A biopolymer-like metal enabled hybrid material with exceptional mechanical prowess.

PubMed

Zhang, Junsong; Cui, Lishan; Jiang, Daqiang; Liu, Yinong; Hao, Shijie; Ren, Yang; Han, Xiaodong; Liu, Zhenyang; Wang, Yunzhi; Yu, Cun; Huan, Yong; Zhao, Xinqing; Zheng, Yanjun; Xu, Huibin; Ren, Xiaobing; Li, Xiaodong

2015-02-10

The design principles for naturally occurring biological materials have inspired us to develop next-generation engineering materials with remarkable performance. Nacre, commonly referred to as nature's armor, is renowned for its unusual combination of strength and toughness. Nature's wisdom in nacre resides in its elaborate structural design and the judicious placement of a unique organic biopolymer with intelligent deformation features. However, up to now, it is still a challenge to transcribe the biopolymer's deformation attributes into a stronger substitute in the design of new materials. In this study, we propose a new design strategy that employs shape memory alloy to transcribe the "J-curve" mechanical response and uniform molecular/atomic level deformation of the organic biopolymer in the design of high-performance hybrid materials. This design strategy is verified in a TiNi-Ti3Sn model material system. The model material demonstrates an exceptional combination of mechanical properties that are superior to other high-performance metal-based lamellar composites known to date. Our design strategy creates new opportunities for the development of high-performance bio-inspired materials.

High-Power Vehicle-Towed TEM for Small Ordnance Detection at Depth

DTIC Science & Technology

2014-02-01

Operations,100A Donner Dr,Oak Ridge,TN, 37830 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10...T. Jeffrey Gamey Battelle, 100A Donner Dr., Oak Ridge, TN 37830 (865) 599-0820 gameytj@battelle.org Geophysicist – Principle Investigator...William Doll Battelle, 100A Donner Dr., Oak Ridge, TN 37830 (865) 599-6165 dollw@battelle.org Geophysicist – modeling assessment, data collection, data

High Mobility Driver Performance Analysis

DTIC Science & Technology

1981-06-01

Adjusted Residuals 25 Table 13. Trials kAll Trials Including Civilian Drivers) During which Critical Incidents Occurred (Or Did Not Occur) 26 Table 14...0.05 (Winer, 1971 )3. At, the close of training an error score had been selected from amons alternative formulations as reasonably representative of...USNPA, Aug 1968. Winer, B. J. Statistical Principles in Experimental Design. Second (2d) edition. McGraw-Hill, New York, 1971 . 35 IN hi a. I i d A-14

Adaptive Voting Algorithms for the Reliable Dissemination of Data in Fault-Prone Distributed Environments

DTIC Science & Technology

2008-01-01

on Op. Sys. Principles, ACM SIGOPS, Brighton , UK , October. Pollack, S. and McQuay, W.K. (2005) ‘Joint battlespace infosphere applications using...the voting protocols for good performance while meeting the reliability requirements of data delivery in a high assurance setting. Two metric quantify...the effectiveness of voting protocols: Data Transfer Efficiency (DTE) and Time-to-Complete (TTC) data delivery . DTE captures the network bandwidth

The Restricted Isometry Property for Time-Frequency Structured Random Matrices

DTIC Science & Technology

2011-06-16

tests illustrating the use of Ψg for compressive sensing are presented in [41]. They illustrate that empirically Ψg performs very similarly to a...E.J., J., Tao, T., Romberg , J.: Robust uncertainty principles: exact signal reconstruction from highly incomplete frequency information. IEEE Trans...Inform. Theory 52(2), 489–509 (2006) [12] Candès, E.J., Romberg , J., Tao, T.: Stable signal recovery from incomplete and inaccurate mea- surements. Comm

64 x 64 thresholding photodetector array for optical pattern recognition

NASA Astrophysics Data System (ADS)

Langenbacher, Harry; Chao, Tien-Hsin; Shaw, Timothy; Yu, Jeffrey W.

1993-10-01

A high performance 32 X 32 peak detector array is introduced. This detector consists of a 32 X 32 array of thresholding photo-transistor cells, manufactured with a standard MOSIS digital 2-micron CMOS process. A built-in thresholding function that is able to perform 1024 thresholding operations in parallel strongly distinguishes this chip from available CCD detectors. This high speed detector offers responses from one to 10 milliseconds that is much higher than the commercially available CCD detectors operating at a TV frame rate. The parallel multiple peaks thresholding detection capability makes it particularly suitable for optical correlator and optoelectronically implemented neural networks. The principle of operation, circuit design and the performance characteristics are described. Experimental demonstration of correlation peak detection is also provided. Recently, we have also designed and built an advanced version of a 64 X 64 thresholding photodetector array chip. Experimental investigation of using this chip for pattern recognition is ongoing.

Energy conversion and storage program

NASA Astrophysics Data System (ADS)

Cairns, E. J.

1992-03-01

The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in: (1) production of new synthetic fuels; (2) development of high-performance rechargeable batteries and fuel cells; (3) development of advanced thermochemical processes for energy conversion; (4) characterization of complex chemical processes; and (5) application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis. Electrochemistry research aims to develop advanced power systems for electric vehicle and stationary energy storage applications. Topics include identification of new electrochemical couples for advanced rechargeable batteries, improvements in battery and fuel-cell materials, and the establishment of engineering principles applicable to electrochemical energy storage and conversion. Chemical Applications research includes topics such as separations, catalysis, fuels, and chemical analyses. Included in this program area are projects to develop improved, energy-efficient methods for processing waste streams from synfuel plants and coal gasifiers. Other research projects seek to identify and characterize the constituents of liquid fuel-system streams and to devise energy-efficient means for their separation. Materials Applications research includes the evaluation of the properties of advanced materials, as well as the development of novel preparation techniques. For example, the use of advanced techniques, such as sputtering and laser ablation, are being used to produce high-temperature superconducting films.

Performance evaluation of a piezoactuator-based single-stage valve system subjected to high temperature

NASA Astrophysics Data System (ADS)

Jeon, Juncheol; Han, Chulhee; Chung, Jye Ung; Choi, Seung-Bok

2015-01-01

In this paper, a novel single-stage valve system activated by a piezostack actuator is proposed and experimentally evaluated at both room temperature (20 °C) and high temperature (100 °C) conditions. A hinge-lever displacement amplifier is adopted in the valve system to magnify the displacement generated from the piezostack actuator. After explaining the operating principle of the proposed piezostack-driven single-stage valve system, the geometric dimensions and mechanical properties of the valve components are discussed in details. An experimental apparatus is then manufactured to evaluate the performances of the valve system such as flow rate. The experimental apparatus consists of a heat chamber, which can regulate the temperature of the valve system and oil, pneumatic-hydraulic cylinders, a hydraulic circuit, a pneumatic circuit, electronic devices, an interface card, and a high voltage amplifier. The pneumatic-hydraulic cylinder transforms the pneumatic pressure into hydraulic pressure. The performances of the valve system regarding spool response, pressure drop, and flow rate are evaluated and presented. In addition, the performance of the valve system under high temperature condition is compared with that under room temperature condition. The experimental results are plotted in both frequency and time domains.

Virtual data

NASA Astrophysics Data System (ADS)

Bjorklund, E.

1994-12-01

In the 1970s, when computers were memory limited, operating system designers created the concept of "virtual memory", which gave users the ability to address more memory than physically existed. In the 1990s, many large control systems have the potential of becoming data limited. We propose that many of the principles behind virtual memory systems (working sets, locality, caching and clustering) can also be applied to data-limited systems, creating, in effect, "virtual data systems". At the Los Alamos National Laboratory's Clinton P. Anderson Meson Physics Facility (LAMPF), we have applied these principles to a moderately sized (10 000 data points) data acquisition and control system. To test the principles, we measured the system's performance during tune-up, production, and maintenance periods. In this paper, we present a general discussion of the principles of a virtual data system along with some discussion of our own implementation and the results of our performance measurements.

Optimal design of high damping force engine mount featuring MR valve structure with both annular and radial flow paths

NASA Astrophysics Data System (ADS)

Nguyen, Q. H.; Choi, S. B.; Lee, Y. S.; Han, M. S.

2013-11-01

This paper focuses on the optimal design of a compact and high damping force engine mount featuring magnetorheological fluid (MRF). In the mount, a MR valve structure with both annular and radial flows is employed to generate a high damping force. First, the configuration and working principle of the proposed MR mount is introduced. The MRF flows in the mount are then analyzed and the governing equations of the MR mount are derived based on the Bingham plastic behavior of the MRF. An optimal design of the MR mount is then performed to find the optimal structure of the MR valve to generate a maximum damping force with certain design constraints. In addition, the gap size of MRF ducts is empirically chosen considering the ‘lockup’ problem of the mount at high frequency. Performance of the optimized MR mount is then evaluated based on finite element analysis and discussions on performance results of the optimized MR mount are given. The effectiveness of the proposed MR engine mount is demonstrated via computer simulation by presenting damping force and power consumption.

Earth Science Principles Pertinent to the General Education Programs in Junior High Schools

ERIC Educational Resources Information Center

Henson, Kenneth Tyrone

1970-01-01

Presents the procedures, and findings of a study designed to identify principles in astronomy, geology, meterology, oceanography and physical geography pertinent to general education programs in junior high schools. (LC)

Low Sound Velocity Contributing to the High Thermoelectric Performance of Ag8SnSe6.

PubMed

Li, Wen; Lin, Siqi; Ge, Binghui; Yang, Jiong; Zhang, Wenqing; Pei, Yanzhong

2016-11-01

Conventional strategies for advancing thermoelectrics by minimizing the lattice thermal conductivity focus on phonon scattering for a short mean free path. Here, a design of slow phonon propagation as an effective approach for high-performance thermoelectrics is shown. Taking Ag 8 SnSe 6 as an example, which shows one of the lowest sound velocities among known thermoelectric semiconductors, the lattice thermal conductivity is found to be as low as 0.2 W m -1 K -1 in the entire temperature range. As a result, a peak thermoelectric figure of merit zT > 1.2 and an average zT as high as ≈0.8 are achieved in Nb-doped materials, without relying on a high thermoelectric power factor. This work demonstrates not only a guiding principle of low sound velocity for minimal lattice thermal conductivity and therefore high zT , but also argyrodite compounds as promising thermoelectric materials with weak chemical bonds and heavy constituent elements.

Transport properties of high-performance all-Heusler Co2CrSi/Cu2CrAl/Co2CrSi giant magnetoresistance device

NASA Astrophysics Data System (ADS)

Bai, Z. Q.; Lu, Y. H.; Shen, L.; Ko, V.; Han, G. C.; Feng, Y. P.

2012-05-01

Transport properties of giant magnetoresistance (MR) junction consisting of trilayer Co2CrSi/Cu2CrAl/Co2CrSi Heusler alloys (L21) are studied using first-principles approach based on density functional theory and the non-equilibrium Green's function method. Highly conductive channels are found in almost the entire k-plane when the magnetizations of the electrodes are parallel, while they are completely blocked in the antiparallel configuration, which leads to a high magnetoresistance ratio (the pessimistic MR ratio is nearly 100%). Furthermore, the calculated I-V curve shows that the device behaves as a good spin valve with a considerable disparity in currents under the parallel and antiparallel magnetic configurations of the electrodes. The Co2CrSi/Cu2CrAl/Co2CrSi junction could be useful for high-performance all-metallic current-perpendicular-to-plane giant magnetoresistance reading head for the next generation high density magnetic storage.

Decoupling analysis of a novel bearingless flux-switching permanent magnet motor

NASA Astrophysics Data System (ADS)

Zhao, Chenyin; Zhu, Huangqiu; Qin, Yuemei

2017-05-01

In this paper, a novel 12/10 stator/rotor pole bearingless flux-switching permanent magnet (BFSPM) motor is proposed to overcome the drawbacks of rotor permanent magnet type bearingless motors. The basic motor configuration, including motor configuration and winding configuration, is introduced firstly. Then, based on the principle of reverse direction magnetization for symmetrical rotor teeth, the radial suspension forces generation principle is analyzed in detail. Finally, decoupling performances between suspension force windings and torque windings are investigated. The results show that the proposed BFSPM not only ensures the merits of high torque output capability compared with conventional 12/10 stator/rotor pole FSPM motor, but also achieves stable radial suspension forces which have little mutual effect with torque. The validity of the proposed structure has been verified by finite element analysis (FEA).

First-principles prediction of solar radiation shielding performance for transparent windows of GdB{sub 6}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Lihua, E-mail: xiaolihua@git.edu.cn; School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083; Guizhou Special Functional Materials 2011 Collaborative Innovation Center, Guizhou Institute of Technology, Guiyang 550003

2016-04-28

The structural, electronic, magnetic, and optical properties of GdB{sub 6} are studied using the first-principles calculations. Calculated values for magnetic and optical properties and lattice constant are found to be consistent with previously reported experimental results. The calculated results show that GdB{sub 6} is a perfect near-infrared absorption/reflectance material that could serve as a solar radiation shielding material for windows with high visible light transmittance, similar to LaB{sub 6}, which is assigned to its plasma oscillation and a collective oscillation (volume plasmon) of carrier electrons. It was found that the magnetic 4f electrons of Gd are not relevant to themore » important optical properties of GdB{sub 6}. These theoretical studies serve as a reference for future studies.« less

Multielectron-Transfer-based Rechargeable Energy Storage of Two-Dimensional Coordination Frameworks with Non-Innocent Ligands.

PubMed

Wada, Keisuke; Sakaushi, Ken; Sasaki, Sono; Nishihara, Hiroshi

2018-04-19

The metallically conductive bis(diimino)nickel framework (NiDI), an emerging class of metal-organic framework (MOF) analogues consisting of two-dimensional (2D) coordination networks, was found to have an energy storage principle that uses both cation and anion insertion. This principle gives high energy led by a multielectron transfer reaction: Its specific capacity is one of the highest among MOF-based cathode materials in rechargeable energy storage devices, with stable cycling performance up to 300 cycles. This mechanism was studied by a wide spectrum of electrochemical techniques combined with density-functional calculations. This work shows that a rationally designed material system of conductive 2D coordination networks can be promising electrode materials for many types of energy devices. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Human factors and ergonomics for primary care.

PubMed

Bowie, Paul; Jeffcott, Shelly

2016-03-01

In the second paper of this series, we provide a brief overview of the scientific discipline of human factors and ergonomics (HFE). Traditionally the HFE focus in healthcare has been in acute hospital settings which are perceived to exhibit characteristics more similar to other high-risk industries already applying related principles and methods. This paper argues that primary care is an area which could benefit extensively from an HFE approach, specifically in improving the performance and well-being of people and organisations. To this end, we define the purpose of HFE, outline its three specialist sub-domains (physical, cognitive and organisational HFE) and provide examples of guiding HFE principles and practices. Additionally, we describe HFE issues of significance to primary care education, improvement and research and outline early plans for building capacity and capability in this setting.

Research on Darrieus-type hydraulic turbine for extra-low head hydropower utilization

NASA Astrophysics Data System (ADS)

Furukawa, A.; Watanabe, S.; Okuma, K.

2012-11-01

A Darrieus-type turbine has been investigated for extra-low head hydropower utilization. In the present paper, authors'research on Darrieus-type hydraulic turbine is briefly reviewed. The working principle of Darrieus turbine is explained with advantage of its simple structure, at first. Then the fluid-dynamic difference between rotating and linear motions of a blade in a uniform flow is clarified with guiding principle of high performance design of Darrieus turbine. Cavitation problem is also described. Next, effects of duct-casing, consisting of an intake, runner section and draft tube, are discussed and a simplified structure of Darrieus turbine is shown by installing the inlet nozzle. Finally, in the practical use, an adjustment of inlet nozzle section by lowering the inlet nozzle height is proposed when flow rate is varied temporally and seasonally.

Design of axisymmetrical tailored concentrators for LED light source applications

NASA Astrophysics Data System (ADS)

Van Giel, Bart; Meuret, Youri; Thienpont, Hugo

2006-04-01

In our contribution we present a solution to an important question in the design of a LED-based illumination engine for projection systems: the collimation of the LED light. We tested the principle in the modification of a common device in non-imaging optics, the compound Parabolic Concentrator. This CPC-like achieves a collection of 72% (ideal reflective coating presumed). This CPC-like was tailored by numerically solving an differential equation. This approach has some serious drawbacks. For a compact collection device with high collimation, an other approach is required. A more elegant design strategy will rely fully on geometrical principles. The result of our work is a compound collection lens that achieves a collection efficiency of 87%, assuming an ideal reflective coating and neglecting Fresnel losses. We study the performance of this device in detail. Further enhancements are suggested.

First principles calculations of optical properties of the armchair SiC nanoribbons with O, F and H termination

NASA Astrophysics Data System (ADS)

Lu, Dao-Bang; Song, Yu-Ling

2018-03-01

Based on density functional theory, we perform first-principles investigations to study the optical properties of the O-, F- and H-terminated SiC nanoribbons with armchair edges (ASiCNRs). By irradiating with an external electromagnetic field, we calculate the dielectric function, reflection spectra, energy loss coefficient and the real part of the conductance. It is demonstrated that the optical constants are sensitive to the low-energy range, different terminal atoms do not make much difference in the shape of the curves of the optical constants for the same-width ASiCNR, and the optical constants of wider nanoribbons usually have higher peaks than that of the narrower ones in low energy range. We hope that our study helps in experimental technology of fabricating high-quality SiC-based nanoscale photoelectric device.

Antitumor properties and modulation of antioxidant enzymes' activity by Aloe vera leaf active principles isolated via supercritical carbon dioxide extraction.

PubMed

El-Shemy, H A; Aboul-Soud, M A M; Nassr-Allah, A A; Aboul-Enein, K M; Kabash, A; Yagi, A

2010-01-01

The aim of this study was to evaluate the potential anticancer properties and modulatory effect of selected Aloe vera (A. vera) active principles on antioxidant enzyme activities. Thus, three anthraquinones (Namely: aloesin, aloe-emodin and barbaloin) were extracted from A. vera leaves by supercritical fluid extraction and subsequently purified by high performance liquid chromatography. Additionally, the N-terminal octapeptide derived from verectin, a biologically active 14 kDa glycoprotein present in A. vera, was also tested. In vivo, active principles exhibited significant prolongation of the life span of tumor-transplanted animals in the following order: barbaloin> octapeptide> aloesin > aloe-emodin. A. vera active principles exhibited significant inhibition on Ehrlich ascite carcinoma cell (EACC) number, when compared to positive control group, in the following order: barbaloin> aloe-emodin > octapeptide > aloesin. Moreover, in trypan blue cell viability assay, active principles showed a significant concentration-dependent cytotoxicity against acute myeloid leukemia (AML) and acute lymphocytes leukemia (ALL) cancerous cells. Furthermore, in MTT cell viability test, aloe-emodin was found to be active against two human colon cancer cell lines (i.e. DLD-1 and HT2), with IC(50) values of 8.94 and 10.78 microM, respectively. Treatments of human AML leukemic cells with active principles (100 microg ml(-1)) resulted in varying intensities of internucleosomal DNA fragmentation, hallmark of cells undergoing apoptosis, in the following order: aloe-emodin> aloesin> barbaloin> octapeptide. Intererstingly, treatment of EACC tumors with active principles resulted in a significant elevation activity of key antioxidant enzymes (SOD, GST, tGPx, and LDH). Our data suggest that the tested A. vera compounds may exert their chemo-preventive effect through modulating antioxidant and detoxification enzyme activity levels, as they are one of the indicators of tumorigenesis. These findings are discussed in the light of the potential of A. vera plant extracts for developing efficient, specific and non-toxic anticancer drugs that are affordable for developing countries.

A review of electrolyte materials and compositions for electrochemical supercapacitors.

PubMed

Zhong, Cheng; Deng, Yida; Hu, Wenbin; Qiao, Jinli; Zhang, Lei; Zhang, Jiujun

2015-11-07

Electrolytes have been identified as some of the most influential components in the performance of electrochemical supercapacitors (ESs), which include: electrical double-layer capacitors, pseudocapacitors and hybrid supercapacitors. This paper reviews recent progress in the research and development of ES electrolytes. The electrolytes are classified into several categories, including: aqueous, organic, ionic liquids, solid-state or quasi-solid-state, as well as redox-active electrolytes. Effects of electrolyte properties on ES performance are discussed in detail. The principles and methods of designing and optimizing electrolytes for ES performance and application are highlighted through a comprehensive analysis of the literature. Interaction among the electrolytes, electro-active materials and inactive components (current collectors, binders, and separators) is discussed. The challenges in producing high-performing electrolytes are analyzed. Several possible research directions to overcome these challenges are proposed for future efforts, with the main aim of improving ESs' energy density without sacrificing existing advantages (e.g., a high power density and a long cycle-life) (507 references).

Simulation and performance analysis of a novel high-accuracy sheathless microfluidic impedance cytometer with coplanar electrode layout.

PubMed

Caselli, Federica; Bisegna, Paolo

2017-10-01

The performance of a novel microfluidic impedance cytometer (MIC) with coplanar configuration is investigated in silico. The main feature of the device is the ability to provide accurate particle-sizing despite the well-known measurement sensitivity to particle trajectory. The working principle of the device is presented and validated by means of an original virtual laboratory providing close-to-experimental synthetic data streams. It is shown that a metric correlating with particle trajectory can be extracted from the signal traces and used to compensate the trajectory-induced error in the estimated particle size, thus reaching high-accuracy. An analysis of relevant parameters of the experimental setup is also presented. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Physical interpretation and application of principles of ultrasonic nondestructive evaluation of high-performance materials

NASA Technical Reports Server (NTRS)

Miller, James G.

1990-01-01

An ultrasonic measurement system employed in the experimental interrogation of the anisotropic properties (through the measurement of the elastic stiffness constants) of the uniaxial graphite-epoxy composites is presented. The continuing effort for the development of improved visualization techniques for physical parameters is discussed. The background is set for the understanding and visualization of the relationship between the phase and energy/group velocity for propagation in high-performance anisotropic materials by investigating the general requirements imposed by the classical wave equation. The consequences are considered when the physical parameters of the anisotropic material are inserted into the classical wave equation by a linear elastic model. The relationship is described between the phase velocity and the energy/group velocity three dimensional surfaces through graphical techniques.

SINGLE-STAGE SPACESHIPS SHOULD BE OUR GOAL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hunter, M.W. Jr.

1963-02-01

The ultimate vehicle for manned space travel within the solar system was considered to be the high-performance single-stage spaceship---a vehicle that could travel from earth to points in space and back time after time. If the performance of single-stage rockets can be made high enough, one can begin to think of reusing equipment exactly as in transport airplane practice. The prospects for a practical gaseous fission rocket have brightened with the recent invention of a new family of systems that operates on a basically different principle. The propellant is heated by radiation from the fission plasma, rather than by directmore » intermixing. Several such systems were suggested. Safety factors were considered to make operation of a spaceship propelled by a gaseous-fission engine safe. (C.E.S.)« less

[Bioactive saponins and glycosides. XIII. Horse chestnut. (3): Quantitative analysis of escins Ia, Ib, IIa, and IIb by means of high performance liquid chromatography].

PubMed

Yoshikawa, M; Murakami, T; Otuki, K; Yamahara, J; Matsuda, H

1999-01-01

As a part of our studies on the characterization of bioactive saponin constituents of horse chestnut trees, a quantitative method using high performance liquid chromatography (HPLC) has been developed for four principle saponin constituents, such as escins Ia, Ib, IIa, and IIb, isolated from the seeds of European horse chestnut trees (Aesculus hippocastanum L., Hippocastanaceae). As an application of this HPLC method, we examined the contents and compositions of these escins in the seeds of Japanese horse chestnut trees (A. turbinata BLUME) and in several commercial materials named as "beta-escin". Additionally, the distribution of escins in the Japanese horse chestnut trees was examined, and escins were found to be contained only in the seeds.

Low-cost synchronization of high-speed audio and video recordings in bio-acoustic experiments.

PubMed

Laurijssen, Dennis; Verreycken, Erik; Geipel, Inga; Daems, Walter; Peremans, Herbert; Steckel, Jan

2018-02-27

In this paper, we present a method for synchronizing high-speed audio and video recordings of bio-acoustic experiments. By embedding a random signal into the recorded video and audio data, robust synchronization of a diverse set of sensor streams can be performed without the need to keep detailed records. The synchronization can be performed using recording devices without dedicated synchronization inputs. We demonstrate the efficacy of the approach in two sets of experiments: behavioral experiments on different species of echolocating bats and the recordings of field crickets. We present the general operating principle of the synchronization method, discuss its synchronization strength and provide insights into how to construct such a device using off-the-shelf components. © 2018. Published by The Company of Biologists Ltd.

First-principles study of mixed eldfellite compounds Nax(Fe1/2M1/2) (SO4)2 (x=0-2, M = Mn, Co, Ni): A new family of high electrode potential cathodes for the sodium-ion battery

NASA Astrophysics Data System (ADS)

Ri, Gum-Chol; Choe, Song-Hyok; Yu, Chol-Jun

2018-02-01

Natural abundance of sodium and its similar behavior to lithium triggered recent extensive studies of cost-effective sodium-ion batteries (SIBs) for large-scale energy storage systems. A challenge is to develop electrode materials with a high electrode potential, specific capacity and a good rate capability. In this work we propose mixed eldfellite compounds Nax(Fe1/2M1/2) (SO4)2 (x = 0-2, M = Mn, Co, Ni) as a new family of high electrode potential cathodes of SIBs and present their material properties predicted by first-principles calculations. The structural optimizations show that these materials have significantly small volume expansion rates below 5% upon Na insertion/desertion with negative Na binding energies. Through the electronic structure calculations, we find band insulating properties and hole (and/or electron) polaron hoping as a possible mechanism for the charge transfer. Especially we confirm the high electrode voltages over 4 V with reasonably high specific capacities. We also investigate the sodium ion mobility by estimating plausible diffusion pathways and calculating the corresponding activation barriers, demonstrating the reasonably fast migrations of sodium ions during the operation. Our calculation results indicate that these mixed eldfellite compounds can be suitable materials for high performance SIB cathodes.

The role of language in mathematical development: evidence from children with specific language impairments.

PubMed

Donlan, Chris; Cowan, Richard; Newton, Elizabeth J; Lloyd, Delyth

2007-04-01

A sample (n=48) of eight-year-olds with specific language impairments is compared with age-matched (n=55) and language matched controls (n=55) on a range of tasks designed to test the interdependence of language and mathematical development. Performance across tasks varies substantially in the SLI group, showing profound deficits in production of the count word sequence and basic calculation and significant deficits in understanding of the place-value principle in Hindu-Arabic notation. Only in understanding of arithmetic principles does SLI performance approximate that of age-matched-controls, indicating that principled understanding can develop even where number sequence production and other aspects of number processing are severely compromised.

The utility of ultra-high performance supercritical fluid chromatography-tandem mass spectrometry (UHPSFC-MS/MS) for clinically relevant steroid analysis.

PubMed

Storbeck, Karl-Heinz; Gilligan, Lorna; Jenkinson, Carl; Baranowski, Elizabeth S; Quanson, Jonathan L; Arlt, Wiebke; Taylor, Angela E

2018-05-15

Liquid chromatography tandem mass spectrometry (LC-MS/MS) assays are considered the reference standard for serum steroid hormone analyses, while full urinary steroid profiles are only achievable by gas chromatography (GC-MS). Both LC-MS/MS and GC-MS have well documented strengths and limitations. Recently, commercial ultra-high performance supercritical fluid chromatography-tandem mass spectrometry (UHPSFC-MS/MS) systems have been developed. These systems combine the resolution of GC with the high-throughput capabilities of UHPLC. Uptake of this new technology into research and clinical labs has been slow, possibly due to the perceived increase in complexity. Here we therefore present fundamental principles of UHPSFC-MS/MS and the likely applications for this technology in the clinical research setting, while commenting on potential hurdles based on our experience to date. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Micro-Spec: A High Performance Compact Spectrometer for Submillimeter Astronomy

NASA Technical Reports Server (NTRS)

Hsieh, Wen-Ting; Moseley, Harvey; Stevenson, Thomas; Brown, Ari; Patel, Amil; U-Yen, Kongpop; Ehsan, Negar; Caltado, Giuseppe; Wollock, Edward

2012-01-01

We describe the micro-Spec, an extremely compact high performance spectrometer for the submillimeter and millimeter spectral ranges. We have designed a fully integrated submillimeter spectrometer based on superconducting microstrip technology and fabricated its critical elements. Using low loss transmission lines, we can produce a fully integrated high resolution submillimeter spectrometer on a single four inch Si wafer. A resolution of 500 can readily be achieved with standard fabrication tolerance, higher with phase trimming. All functions of the spectrometer are integrated - light is coupled to the micro strip circuit with a planar antenna, the spectra discrimination is achieved using a synthetic grating, orders are separated using a built-in planar filter, and the light is detected using photon counting Microwave Kinetic Inductance Detectors (MKID). We will discus the design principle of the instrument, describe its technical advantages, and report the progress on the development of the instrument.

Mu-Spec: A High Performance Compact Spectrometer for Submillimeter Astronomy

NASA Technical Reports Server (NTRS)

Hsieh, Wen-Ting; Moseley, Harvey; Stevenson, Thomas; Brown, Ari; Patel, Amil; U-yen, Kongpop; Ehsan, Negar; Cataldo, Giuseppe; Wollack, Ed

2012-01-01

We describe the Mu-Spec, an extremely compact high performance spectrometer for the submillimeter and millimeter spectral ranges. We have designed a fully integrated submillimeter spectrometer based on superconducting microstrip technology and fabricated its critical elements. Using low loss transmission lines, we can produce a fully integrated high resolution submillimeter spectrometer on a single four inch Si wafer. A resolution of 500 can readily be achieved with standard fabrication tolerance, higher with phase trimming. All functions of the spectrometer are integrated - light is coupled to the microstrip circuit with a planar antenna, the spectra discrimination is achieved using a synthetic grating, orders are separated using a built-in planar filter, and the light is detected using photon counting Microwave Kinetic Inductance Detectors (MKID). We will discus the design principle of the instrument, describe its technical advantages, and report the progress on the development of the instrument.

High-speed low-complexity video coding with EDiCTius: a DCT coding proposal for JPEG XS

NASA Astrophysics Data System (ADS)

Richter, Thomas; Fößel, Siegfried; Keinert, Joachim; Scherl, Christian

2017-09-01

In its 71th meeting, the JPEG committee issued a call for low complexity, high speed image coding, designed to address the needs of low-cost video-over-ip applications. As an answer to this call, Fraunhofer IIS and the Computing Center of the University of Stuttgart jointly developed an embedded DCT image codec requiring only minimal resources while maximizing throughput on FPGA and GPU implementations. Objective and subjective tests performed for the 73rd meeting confirmed its excellent performance and suitability for its purpose, and it was selected as one of the two key contributions for the development of a joined test model. In this paper, its authors describe the design principles of the codec, provide a high-level overview of the encoder and decoder chain and provide evaluation results on the test corpus selected by the JPEG committee.

Atomic and close-to-atomic scale manufacturing—A trend in manufacturing development

NASA Astrophysics Data System (ADS)

Fang, Fengzhou

2016-12-01

Manufacturing is the foundation of a nation's economy. It is the primary industry to promote economic and social development. To accelerate and upgrade China's manufacturing sector from "precision manufacturing" to "high-performance and high-quality manufacturing", a new breakthrough should be found in terms of achieving a "leap-frog development". Unlike conventional manufacturing, the fundamental theory of "Manufacturing 3.0" is beyond the scope of conventional theory; rather, it is based on new principles and theories at the atomic and/or closeto- atomic scale. Obtaining a dominant role at the international level is a strategic move for China's progress.

Water/alcohol soluble conjugated polymers as highly efficient electron transporting/injection layer in optoelectronic devices.

PubMed

Huang, Fei; Wu, Hongbin; Cao, Yong

2010-07-01

Water/alcohol soluble conjugated polymers (WSCPs) can be processed from water or other polar solvents, which offer good opportunities to avoid interfacial mixing upon fabrication of multilayer polymer optoelectronic devices by solution processing, and can dramatically improve charge injection from high work-function metal cathode resulting in greatly enhancement of the device performance. In this critical review, the authors provide a brief review of recent developments in this field, including the materials design, functional principles, and their unique applications as interface modification layer in solution-processable multilayer optoelectronic devices (135 references).

Coefficient of performance of Stirling refrigerators

NASA Astrophysics Data System (ADS)

E Mungan, Carl

2017-09-01

Stirling coolers transfer heat in or out of the working fluid during all four stages of their operation, and their coefficient of performance depends on whether the non-isothermal heat exchanges are performed reversibly or irreversibly. Both of these possibilities can in principle be arranged. Notably, if the working fluid is an ideal gas, the input of energy in the form of heat during one isochoric step is equal in magnitude to the output during the other isochoric step in the cycle. The theoretical performance of the fridge can then attain the reversible Carnot limit if a regenerator is used, which is a high heat capacity material through which the gas flows. Various Stirling refrigerator configurations are analysed in this article at a level of presentation suitable for an introductory undergraduate thermodynamics course.

A New Set of Forces

DTIC Science & Technology

2012-12-01

correcting forces is the free market itself. Unfortunately, macroeconomic principles do not always prove useful at the microeconomic level...model for this discussion are not relevant, but the underlying principle of the model is—forces can be self-correcting. Any im- balance in one...Performance-based acqui- sition appears to be one of those principles that looks good on paper and has proved quite successful in private industry but has had

An Evaluation of the Cognitive and Affective Performance of an Integrated Set of CAI Materials in the Principles of Macroeconomics. Studies in Economic Education, No. 4.

ERIC Educational Resources Information Center

Daellenbach, Lawrence A.; And Others

The purpose of this study was to determine the effect of computer assisted instruction (CAI) on the cognitive and affective development of college students enrolled in a principles of macroeconomics course. The hypotheses of the experiment were stated as follows: In relation to the traditional principles course, the experimental treatment will…

Human error identification for laparoscopic surgery: Development of a motion economy perspective.

PubMed

Al-Hakim, Latif; Sevdalis, Nick; Maiping, Tanaphon; Watanachote, Damrongpan; Sengupta, Shomik; Dissaranan, Charuspong

2015-09-01

This study postulates that traditional human error identification techniques fail to consider motion economy principles and, accordingly, their applicability in operating theatres may be limited. This study addresses this gap in the literature with a dual aim. First, it identifies the principles of motion economy that suit the operative environment and second, it develops a new error mode taxonomy for human error identification techniques which recognises motion economy deficiencies affecting the performance of surgeons and predisposing them to errors. A total of 30 principles of motion economy were developed and categorised into five areas. A hierarchical task analysis was used to break down main tasks of a urological laparoscopic surgery (hand-assisted laparoscopic nephrectomy) to their elements and the new taxonomy was used to identify errors and their root causes resulting from violation of motion economy principles. The approach was prospectively tested in 12 observed laparoscopic surgeries performed by 5 experienced surgeons. A total of 86 errors were identified and linked to the motion economy deficiencies. Results indicate the developed methodology is promising. Our methodology allows error prevention in surgery and the developed set of motion economy principles could be useful for training surgeons on motion economy principles. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Aesthetic coatings for concrete bridge components

NASA Astrophysics Data System (ADS)

Kriha, Brent R.

This thesis evaluated the durability and aesthetic performance of coating systems for utilization in concrete bridge applications. The principle objectives of this thesis were: 1) Identify aesthetic coating systems appropriate for concrete bridge applications; 2) Evaluate the performance of the selected systems through a laboratory testing regimen; 3) Develop guidelines for coating selection, surface preparation, and application. A series of site visits to various bridges throughout the State of Wisconsin provided insight into the performance of common coating systems and allowed problematic structural details to be identified. To aid in the selection of appropriate coating systems, questionnaires were distributed to coating manufacturers, bridge contractors, and various DOT offices to identify high performing coating systems and best practices for surface preparation and application. These efforts supplemented a literature review investigating recent publications related to formulation, selection, surface preparation, application, and performance evaluation of coating materials.

Origin of high thermoelectric performance of FeNb1−xZr/HfxSb1−ySny alloys: A first-principles study

PubMed Central

Zhang, Xiwen; Wang, Yuanxu; Yan, Yuli; Wang, Chao; Zhang, Guangbiao; Cheng, Zhenxiang; Ren, Fengzhu; Deng, Hao; Zhang, Jihua

2016-01-01

The previous experimental work showed that Hf- or Zr-doping has remarkably improved the thermoelectric performance of FeNbSb. Here, the first-principles method was used to explore the possible reason for such phenomenon. The substitution of X (Zr/Hf) atoms at Nb sites increases effective hole-pockets, total density of states near the Fermi level (EF), and hole mobility to largely enhance electrical conductivity. It is mainly due to the shifting the EF to lower energy and the nearest Fe atoms around X atoms supplying more d-states to hybrid with X d-states at the vicinity of the EF. Moreover, we find that the X atoms indirectly affect the charge distribution around Nb atoms via their nearest Fe atoms, resulting in the reduced energy difference in the valence band edge, contributing to enhanced Seebeck coefficients. In addition, the further Bader charge analysis shows that the reason of more holes by Hf-doping than Zr in the experiment is most likely derived from Hf atoms losing less electrons and the stronger hybridization between Hf atoms and their nearest Fe atoms. Furthermore, we predict that Hf/Sn co-doping may be an effective strategy to further optimize the thermoelectric performance of half-Heusler (HH) compounds. PMID:27604826

Technological processes of grating light valve as diffractive spatial light modulator in laser phototypesetting system

NASA Astrophysics Data System (ADS)

Zhang, Wei; Geng, Yu; Hou, Changlun; Yang, Guoguang; Bai, Jian

2008-11-01

Grating Light Valve (GLV) is a kind of optics device based on Micro-Opto-Electro-Mechanical System (MOEMS) technology, utilizing diffraction principle to switch, attenuate and modulate light. In this paper, traditional GLV device's structure and its working principle are illuminated, and a kind of modified GLV structure is presented, with details introduction of the fabrication technology. The GLV structure includes single crystal silicon substrate, silicon dioxide isolating layer, aluminum layer of fixed ribbons and silicon nitride of movable ribbons. In the fabrication, lots of techniques are adopted, such as low-pressure chemical vapor deposition (LPCVD), photolithography, etching and evaporation. During the fabrication processes, Photolithography is a fundamental and fatal technology, which determines etching result and GLV quality. Some methods are proposed through repeated experiments, to improve etching result greatly and guide the practical application. This kind of GLV device can be made both small and inexpensively, and has been tested to show proper range of actuation under DC bias, with good performance. The GLV device also has merits such as low cost, simple technology, high fill ratio and low driving voltage. It can properly be well used and match the demands of high light power needed in laser phototypesetting system, as a high-speed, high-resolution light modulator.

Projection lenses for high-resolution ablation with excimer lasers: high-performance, wide-field and high-UV laser power

NASA Astrophysics Data System (ADS)

Schlichting, Johannes; Winkler, Kerstin; Koerner, Lienhard; Schletterer, Thomas; Burghardt, Berthold; Kahlert, Hans-Juergen

2000-10-01

The productive and accurate ablation of microstructures demands the precise imaging of a mask pattern onto the substrate under work. The job can be done with high performance wide field lenses as a key component of ablation equipment. The image field has dimensions of 20 to 30 mm. Typical dimensions and accuracy of the microstructures are in the order of some microns. On the other hand, the working depth of focus (DOF) has to be in the order of some 10 microns to be successful on drilling through 20 to 50 μm substrates. All these features have to be reached under the conditions of high power laser UV light. Some design principles for such systems are applied, such as optimum number of elements, minimum tolerance sensitivity, material restrictions for the lens elements as well as mechanical parts (mounting), restrictions of possible power densities on lens surfaces (including ghosts), matched quality for the manufactures system. The special applications require appropriate performance criteria for theoretical calculation and measurements, which allow to conclude the performance of the application. The base is wave front calculation and measurement (using Shack- Hartmann sensor) in UV. Derived criteria are calculated and compared with application results.

Selective vulnerability of Rich Club brain regions is an organizational principle of structural connectivity loss in Huntington’s disease

PubMed Central

Seunarine, Kiran K.; Razi, Adeel; Cole, James H.; Gregory, Sarah; Durr, Alexandra; Roos, Raymund A. C.; Stout, Julie C.; Landwehrmeyer, Bernhard; Scahill, Rachael I.; Clark, Chris A.; Rees, Geraint

2015-01-01

Huntington’s disease can be predicted many years before symptom onset, and thus makes an ideal model for studying the earliest mechanisms of neurodegeneration. Diffuse patterns of structural connectivity loss occur in the basal ganglia and cortex early in the disease. However, the organizational principles that underlie these changes are unclear. By understanding such principles we can gain insight into the link between the cellular pathology caused by mutant huntingtin and its downstream effect at the macroscopic level. The ‘rich club’ is a pattern of organization established in healthy human brains, where specific hub ‘rich club’ brain regions are more highly connected to each other than other brain regions. We hypothesized that selective loss of rich club connectivity might represent an organizing principle underlying the distributed pattern of structural connectivity loss seen in Huntington’s disease. To test this hypothesis we performed diffusion tractography and graph theoretical analysis in a pseudo-longitudinal study of 50 premanifest and 38 manifest Huntington’s disease participants compared with 47 healthy controls. Consistent with our hypothesis we found that structural connectivity loss selectively affected rich club brain regions in premanifest and manifest Huntington’s disease participants compared with controls. We found progressive network changes across controls, premanifest Huntington’s disease and manifest Huntington’s disease characterized by increased network segregation in the premanifest stage and loss of network integration in manifest disease. These regional and whole brain network differences were highly correlated with cognitive and motor deficits suggesting they have pathophysiological relevance. We also observed greater reductions in the connectivity of brain regions that have higher network traffic and lower clustering of neighbouring regions. This provides a potential mechanism that results in a characteristic pattern of structural connectivity loss targeting highly connected brain regions with high network traffic and low clustering of neighbouring regions. Our findings highlight the role of the rich club as a substrate for the structural connectivity loss seen in Huntington’s disease and have broader implications for understanding the connection between molecular and systems level pathology in neurodegenerative disease. PMID:26384928

Selective vulnerability of Rich Club brain regions is an organizational principle of structural connectivity loss in Huntington's disease.

PubMed

McColgan, Peter; Seunarine, Kiran K; Razi, Adeel; Cole, James H; Gregory, Sarah; Durr, Alexandra; Roos, Raymund A C; Stout, Julie C; Landwehrmeyer, Bernhard; Scahill, Rachael I; Clark, Chris A; Rees, Geraint; Tabrizi, Sarah J

2015-11-01

Huntington's disease can be predicted many years before symptom onset, and thus makes an ideal model for studying the earliest mechanisms of neurodegeneration. Diffuse patterns of structural connectivity loss occur in the basal ganglia and cortex early in the disease. However, the organizational principles that underlie these changes are unclear. By understanding such principles we can gain insight into the link between the cellular pathology caused by mutant huntingtin and its downstream effect at the macroscopic level. The 'rich club' is a pattern of organization established in healthy human brains, where specific hub 'rich club' brain regions are more highly connected to each other than other brain regions. We hypothesized that selective loss of rich club connectivity might represent an organizing principle underlying the distributed pattern of structural connectivity loss seen in Huntington's disease. To test this hypothesis we performed diffusion tractography and graph theoretical analysis in a pseudo-longitudinal study of 50 premanifest and 38 manifest Huntington's disease participants compared with 47 healthy controls. Consistent with our hypothesis we found that structural connectivity loss selectively affected rich club brain regions in premanifest and manifest Huntington's disease participants compared with controls. We found progressive network changes across controls, premanifest Huntington's disease and manifest Huntington's disease characterized by increased network segregation in the premanifest stage and loss of network integration in manifest disease. These regional and whole brain network differences were highly correlated with cognitive and motor deficits suggesting they have pathophysiological relevance. We also observed greater reductions in the connectivity of brain regions that have higher network traffic and lower clustering of neighbouring regions. This provides a potential mechanism that results in a characteristic pattern of structural connectivity loss targeting highly connected brain regions with high network traffic and low clustering of neighbouring regions. Our findings highlight the role of the rich club as a substrate for the structural connectivity loss seen in Huntington's disease and have broader implications for understanding the connection between molecular and systems level pathology in neurodegenerative disease. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain.

Some Practical Universal Noiseless Coding Techniques

NASA Technical Reports Server (NTRS)

Rice, Robert F.

1994-01-01

Report discusses noiseless data-compression-coding algorithms, performance characteristics and practical consideration in implementation of algorithms in coding modules composed of very-large-scale integrated circuits. Report also has value as tutorial document on data-compression-coding concepts. Coding techniques and concepts in question "universal" in sense that, in principle, applicable to streams of data from variety of sources. However, discussion oriented toward compression of high-rate data generated by spaceborne sensors for lower-rate transmission back to earth.

Principles and Application of Magnetic Rubber Testing for Crack Detection in High-Strength Steel Components: II. Residual-Field Inspection

DTIC Science & Technology

2014-12-01

and low Hmax. In this way, the flux density in the material for the specimen with intermediate k (k = 36.4) magnetised using Hmax = 250 Oe... aerospace components for surface-breaking fatigue cracks. In the residual-field variant of MRT, inspections are performed following the application...packages which can adequately predict the fields produced in practical residual-field MRT. Finally, central- conductor MRT, for which there are fewer

Probing buried layers by photoelectron spectromicroscopy with hard x-ray excitation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiemann, C.; Patt, M.; Cramm, S.

We report about a proof-of-principle experiment which explores the perspectives of performing hard x-ray photoemission spectromicroscopy with high lateral resolution. Our results obtained with an energy-filtered photoemission microscope at the PETRA III storage ring facility using hard x-ray excitation up to 6.5 keV photon energy demonstrate that it is possible to obtain selected-area x-ray photoemission spectra from regions less than 500 nm in diameter.

Interface design principles for high-performance organic semiconductor devices

DOE PAGES

Nie, Wanyi; Gupta, Gautam; Crone, Brian K.; ...

2015-03-23

Organic solar cells (OSCs) are a promising cost-effective candidate in next generation photovoltaic technology. However, a critical bottleneck for OSCs is the electron/hole recombination loss through charge transfer state at the interface, which greatly limits the power conversion efficiency. W. Nie, A. Mohite, and co-workers demonstrate a simple strategy of suppressing the recombination rate by inserting a spacer layer at the donor-acceptor interface, resulting in a dramatic increase in power conversion efficiency.

Magic Numbers in Small Iron Clusters: A First-Principles Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Eunja; Mohrland, Andrew B.; Weck, Philippe F.

2014-10-03

We perform ab initio spin-polarized density functional calculations of Fen aggregates with n ≤ 17 atoms to reveal the origin of the observed magic numbers, which indicate particularly high stability of clusters with 7, 13 and 15 atoms. Our results clarify the controversy regarding the ground state geometry of clusters such as Fe5and indicate that magnetism plays an important role in determining the stability and magic numbers in small iron clusters.

Self-aligned photolithography for the fabrication of fully transparent high-voltage devices

NASA Astrophysics Data System (ADS)

Zhang, Yonghui; Mei, Zengxia; Huo, Wenxing; Wang, Tao; Liang, Huili; Du, Xiaolong

2018-05-01

High-voltage devices, working in the range of hundreds of volts, are indispensable elements in the driving or readout circuits for various kinds of displays, integrated microelectromechanical systems and x-ray imaging sensors. However, the device performances are found hardly uniform or repeatable due to the misalignment issue, which are extremely common for offset drain high-voltage devices. To resolve this issue, this article reports a set of self-aligned photolithography technology for the fabrication of high-voltage devices. High-performance fully-transparent high-voltage thin film transistors, diodes and logic inverters are successfully fabricated with this technology. Unlike other self-aligned routes, opaque masks are introduced on the backside of the transparent substrate to facilitate proximity exposure method. The photolithography process is simulated and analyzed with technology computer aided design simulation to explain the working principle of the proximity exposure method. The substrate thickness is found to be vital for the implementation of this technology based on both simulation and experimental results. The electrical performance of high-voltage devices is dependent on the offset length, which can be delicately modulated by changing the exposure dose. The presented self-aligned photolithography technology is proved to be feasible in high-voltage circuits, demonstrating its huge potential in practical industrial applications.

Multiflash X ray with Image Detanglement for Single Image Isolation

DTIC Science & Technology

2017-08-31

known and separated into individual images. A proof-of- principle study was performed using 4 X-ray flashes and copper masks with sub-millimeter holes...Popular Science article.2 For decades, that basic concept dominated the color television market . Those were the days when a large color television...proof-of- principle study was performed using 4 X-ray flashes and copper masks with sub-millimeter holes that allowed development of the required image

Structural and electronic phase transitions of ThS 2 from first-principles calculations

DOE PAGES

Guo, Yongliang; Wang, Changying; Qiu, Wujie; ...

2016-10-07

Performed a systematic study using first-principles methods of the pressure-induced structural and electronic phase transitions in ThS 2, which may play an important role in the next generation nuclear energy fuel technology.

Management of Instructional Development: A Matter of Principles.

ERIC Educational Resources Information Center

Patterson, Amos C.; Gilger, Rebecca L.

1979-01-01

Examines how instructional development processes can be successfully managed. Principles of management are offered for setting precise goals; acceptance of these goals; and maximizing self-concept through formal rewards that are goal oriented, through performance evaluation, and through change analysis. (RAO)

Performance-based planning and programming guidebook.

DOT National Transportation Integrated Search

2013-09-01

"Performance-based planning and programming (PBPP) refers to the application of performance management principles within the planning and programming processes of transportation agencies to achieve desired performance outcomes for the multimodal tran...

Advanced Li-Ion Hybrid Supercapacitors Based on 3D Graphene-Foam Composites.

PubMed

Liu, Wenwen; Li, Jingde; Feng, Kun; Sy, Abel; Liu, Yangshuai; Lim, Lucas; Lui, Gregory; Tjandra, Ricky; Rasenthiram, Lathankan; Chiu, Gordon; Yu, Aiping

2016-10-05

Li-ion hybrid supercapacitors (LIHSs) have recently attracted increasing attention as a new and promising energy storage device. However, it is still a great challenge to construct novel LIHSs with high-performance due to the majority of battery-type anodes retaining the sluggish kinetics of Li-ion storage and most capacitor-type cathodes with low specific capacitance. To solve this problem, 3D graphene-wrapped MoO 3 nanobelt foam with the unique porous network structure has been designed and prepared as anode material, which delivers high capacity, improved rate performance, and enhanced cycle stability. First-principles calculation reveals that the combination of graphene dramatically reduces the diffusion energy barrier of Li + adsorbed on the surface of MoO 3 nanobelt, thus improving its electrochemical performance. Furthermore, 3D graphene-wrapped polyaniline nanotube foam derived carbon is employed as a new type of capacitor-type cathode, demonstrating high specific capacitance, good rate performance, and long cycle stability. Benefiting from these two graphene foam-enhanced materials, the constructed LIHSs show a wide operating voltage range (3.8 V), a long stable cycle life (90% capacity retention after 3000 cycles), a high energy density (128.3 Wh·kg -1 ), and a high power density (13.5 kW·kg -1 ). These encouraging performances indicate that the obtained LIHSs may have promising prospect as next-generation energy-storage devices.

The Four-Quadrant Phase-Mask Coronagraph. I. Principle

NASA Astrophysics Data System (ADS)

Rouan, D.; Riaud, P.; Boccaletti, A.; Clénet, Y.; Labeyrie, A.

2000-11-01

We describe a new type of coronagraph, based on the principle of a phase mask as proposed by Roddier and Roddier a few years ago but using an original mask design found by one of us (D. R.), a four-quadrant binary phase mask (0, π) covering the full field of view at the focal plane. The mutually destructive interferences of the coherent light from the main source produce a very efficient nulling. The computed rejection rate of this coronagraph appears to be very high since, when perfectly aligned and phase-error free, it could in principle reduce the total amount of light from the bright source by a factor of 108, corresponding to a gain of 20 mag in brightness at the location of the first Airy ring, relative to the Airy peak. In the real world the gain is of course reduced by a strong factor, but nulling is still performing quite well, provided that the perturbation of the phase, for instance, due to the Earth's atmosphere, is efficiently corrected by adaptive optics. We show from simulations that a detection at a contrast of 10 mag between a star and a faint companion is achievable in excellent conditions, while 8 mag appears routinely feasible. This coronagraph appears less sensitive to atmospheric turbulence and has a larger dynamic range than other recently proposed nulling techniques: the phase-mask coronagraph (by Roddier and Roddier) or the Achromatic Interfero-Coronagraph (by Gay and Rabbia). We present the principle of the four-quadrant coronagraph and results of a first series of simulations. We compare those results with theoretical performances of other devices. We briefly analyze the different limitations in space or ground-based observations, as well as the issue of manufacturing the device. We also discuss several ways to improve the detection of a faint companion around a bright object. We conclude that, with respect to previous techniques, an instrument equipped with this coronagraph should have better performance and even enable the imaging of extrasolar giant planets at a young stage, when coupled with additional cleaning techniques.

Capturing multidimensionality in stroke aphasia: mapping principal behavioural components to neural structures

PubMed Central

Butler, Rebecca A.

2014-01-01

Stroke aphasia is a multidimensional disorder in which patient profiles reflect variation along multiple behavioural continua. We present a novel approach to separating the principal aspects of chronic aphasic performance and isolating their neural bases. Principal components analysis was used to extract core factors underlying performance of 31 participants with chronic stroke aphasia on a large, detailed battery of behavioural assessments. The rotated principle components analysis revealed three key factors, which we labelled as phonology, semantic and executive/cognition on the basis of the common elements in the tests that loaded most strongly on each component. The phonology factor explained the most variance, followed by the semantic factor and then the executive-cognition factor. The use of principle components analysis rendered participants’ scores on these three factors orthogonal and therefore ideal for use as simultaneous continuous predictors in a voxel-based correlational methodology analysis of high resolution structural scans. Phonological processing ability was uniquely related to left posterior perisylvian regions including Heschl’s gyrus, posterior middle and superior temporal gyri and superior temporal sulcus, as well as the white matter underlying the posterior superior temporal gyrus. The semantic factor was uniquely related to left anterior middle temporal gyrus and the underlying temporal stem. The executive-cognition factor was not correlated selectively with the structural integrity of any particular region, as might be expected in light of the widely-distributed and multi-functional nature of the regions that support executive functions. The identified phonological and semantic areas align well with those highlighted by other methodologies such as functional neuroimaging and neurostimulation. The use of principle components analysis allowed us to characterize the neural bases of participants’ behavioural performance more robustly and selectively than the use of raw assessment scores or diagnostic classifications because principle components analysis extracts statistically unique, orthogonal behavioural components of interest. As such, in addition to improving our understanding of lesion–symptom mapping in stroke aphasia, the same approach could be used to clarify brain–behaviour relationships in other neurological disorders. PMID:25348632

Pump-probe Kelvin-probe force microscopy: Principle of operation and resolution limits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murawski, J.; Graupner, T.; Milde, P., E-mail: peter.milde@tu-dresden.de

Knowledge on surface potential dynamics is crucial for understanding the performance of modern-type nanoscale devices. We describe an electrical pump-probe approach in Kelvin-probe force microscopy that enables a quantitative measurement of dynamic surface potentials at nanosecond-time and nanometer-length scales. Also, we investigate the performance of pump-probe Kelvin-probe force microscopy with respect to the relevant experimental parameters. We exemplify a measurement on an organic field effect transistor that verifies the undisturbed functionality of our pump-probe approach in terms of simultaneous and quantitative mapping of topographic and electronic information at a high lateral and temporal resolution.

Robust Fixed-Structure Controller Synthesis

NASA Technical Reports Server (NTRS)

Corrado, Joseph R.; Haddad, Wassim M.; Gupta, Kajal (Technical Monitor)

2000-01-01

The ability to develop an integrated control system design methodology for robust high performance controllers satisfying multiple design criteria and real world hardware constraints constitutes a challenging task. The increasingly stringent performance specifications required for controlling such systems necessitates a trade-off between controller complexity and robustness. The principle challenge of the minimal complexity robust control design is to arrive at a tractable control design formulation in spite of the extreme complexity of such systems. Hence, design of minimal complexitY robust controllers for systems in the face of modeling errors has been a major preoccupation of system and control theorists and practitioners for the past several decades.

Perovskite solar cells: from materials to devices.

PubMed

Jung, Hyun Suk; Park, Nam-Gyu

2015-01-07

Perovskite solar cells based on organometal halide light absorbers have been considered a promising photovoltaic technology due to their superb power conversion efficiency (PCE) along with very low material costs. Since the first report on a long-term durable solid-state perovskite solar cell with a PCE of 9.7% in 2012, a PCE as high as 19.3% was demonstrated in 2014, and a certified PCE of 17.9% was shown in 2014. Such a high photovoltaic performance is attributed to optically high absorption characteristics and balanced charge transport properties with long diffusion lengths. Nevertheless, there are lots of puzzles to unravel the basis for such high photovoltaic performances. The working principle of perovskite solar cells has not been well established by far, which is the most important thing for understanding perovksite solar cells. In this review, basic fundamentals of perovskite materials including opto-electronic and dielectric properties are described to give a better understanding and insight into high-performing perovskite solar cells. In addition, various fabrication techniques and device structures are described toward the further improvement of perovskite solar cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultra-high-Q phononic resonators on-chip at cryogenic temperatures

NASA Astrophysics Data System (ADS)

Kharel, Prashanta; Chu, Yiwen; Power, Michael; Renninger, William H.; Schoelkopf, Robert J.; Rakich, Peter T.

2018-06-01

Long-lived, high-frequency phonons are valuable for applications ranging from optomechanics to emerging quantum systems. For scientific as well as technological impact, we seek high-performance oscillators that offer a path toward chip-scale integration. Confocal bulk acoustic wave resonators have demonstrated an immense potential to support long-lived phonon modes in crystalline media at cryogenic temperatures. So far, these devices have been macroscopic with cm-scale dimensions. However, as we push these oscillators to high frequencies, we have an opportunity to radically reduce the footprint as a basis for classical and emerging quantum technologies. In this paper, we present novel design principles and simple microfabrication techniques to create high performance chip-scale confocal bulk acoustic wave resonators in a wide array of crystalline materials. We tailor the acoustic modes of such resonators to efficiently couple to light, permitting us to perform a non-invasive laser-based phonon spectroscopy. Using this technique, we demonstrate an acoustic Q-factor of 2.8 × 107 (6.5 × 106) for chip-scale resonators operating at 12.7 GHz (37.8 GHz) in crystalline z-cut quartz (x-cut silicon) at cryogenic temperatures.

10 CFR 433.6 - Sustainable principles for siting, design and construction. [Reserved

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 3 2013-01-01 2013-01-01 false Sustainable principles for siting, design and construction... FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH-RISE RESIDENTIAL BUILDINGS § 433.6 Sustainable principles for siting, design and construction. [Reserved] ...

10 CFR 433.6 - Sustainable principles for siting, design and construction. [Reserved

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 3 2012-01-01 2012-01-01 false Sustainable principles for siting, design and construction... FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH-RISE RESIDENTIAL BUILDINGS § 433.6 Sustainable principles for siting, design and construction. [Reserved] ...

10 CFR 433.6 - Sustainable principles for siting, design and construction. [Reserved

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 3 2014-01-01 2014-01-01 false Sustainable principles for siting, design and construction... FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH-RISE RESIDENTIAL BUILDINGS § 433.6 Sustainable principles for siting, design and construction. [Reserved] ...

A first-principles study of hydrogen storage capacity based on Li-Na-decorated silicene.

PubMed

Sheng, Zhe; Wu, Shujing; Dai, Xianying; Zhao, Tianlong; Hao, Yue

2018-05-23

Surface decoration with alkali metal adatoms has been predicted to be promising for silicene to obtain high hydrogen storage capacity. Herein, we performed a detailed study of the hydrogen storage properties of Li and Na co-decorated silicene (Li-Na-decorated silicene) based on first-principles calculations using van der Waals correction. The hydrogen adsorption behaviors, including the adsorption order, the maximum capacity, and the corresponding mechanism were analyzed in detail. Our calculations show that up to three hydrogen molecules can firmly bind to each Li atom and six for each Na atom, respectively. The hydrogen storage capacity is estimated to be as high as 6.65 wt% with a desirable average adsorption energy of 0.29 eV/H2. It is confirmed that both the charge-induced electrostatic interaction and the orbital hybridizations play a great role in hydrogen storage. Our results may enhance our fundamental understanding of the hydrogen storage mechanism, which is of great importance for the practical application of Li-Na-decorated silicene in hydrogen storage.

Unique Reactivity of Transition Metal Atoms Embedded in Graphene to CO, NO, O₂ and O Adsorption: A First-Principles Investigation.

PubMed

Chu, Minmin; Liu, Xin; Sui, Yanhui; Luo, Jie; Meng, Changgong

2015-10-27

Taking the adsorption of CO, NO, O₂ and O as probes, we investigated the electronic structure of transition metal atoms (TM, TM = Fe, Co, Ni, Cu and Zn) embedded in graphene by first-principles-based calculations. We showed that these TM atoms can be effectively stabilized on monovacancy defects on graphene by forming plausible interactions with the C atoms associated with dangling bonds. These interactions not only give rise to high energy barriers for the diffusion and aggregation of the embedded TM atoms to withstand the interference of reaction environments, but also shift the energy levels of TM-d states and regulate the reactivity of the embedded TM atoms. The adsorption of CO, NO, O₂ and O correlates well with the weight averaged energy level of TM-d states, showing the crucial role of interfacial TM-C interactions on manipulating the reactivity of embedded TM atoms. These findings pave the way for the developments of effective monodispersed atomic TM composites with high stability and desired performance for gas sensing and catalytic applications.

Assessment of GPS Multifrequency Signal Characteristics During Periods of Ionospheric Scintillations from an Anomaly Crest Location

NASA Astrophysics Data System (ADS)

Goswami, S.; Paul, K. S.; Paul, A.

2017-09-01

Multifrequency GPS transmissions have provided the opportunity for testing the applicability of the principle of frequency diversity for scintillation mitigation. Published results addressing this issue with quantified estimates are not available in literature, at least from the anomaly crest location of the Indian longitude sector. Multifrequency scattering within the same L band is often the attributed cause behind simultaneous decorrelated signal fluctuations. The present paper aims to provide proportion of time during scintillation patches that decorrelations are found across GPS L1, L2, and L5 frequencies associated with high S4, corresponding high values of scattering coefficients, and large receiver position deviations thereby seriously compromising the performance of satellite-based navigation system. Results from the anomaly crest station at Calcutta indicate maximum 40% of scintillation time during February-April 2014 and 33% during August-October 2014 that the signals are decorrelated. It is important to note that it is only during these time intervals that the principle of frequency diversity could be applied for scintillation mitigation.

A molecular design principle of lyotropic liquid-crystalline conjugated polymers with directed alignment capability for plastic electronics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Bong-Gi; Jeong, Eun Jeong; Chung, Jong Won

Conjugated polymers with a one-dimensional p-orbital overlap exhibit optoelectronic anisotropy. Their unique anisotropic properties can be fully realized in device applications only when the conjugated chains are aligned. Here, we report a molecular design principle of conjugated polymers to achieve concentration-regulated chain planarization, self-assembly, liquid-crystal-like good mobility and non-interdigitated side chains. As a consequence of these intra- and intermolecular attributes, chain alignment along an applied flow field occurs. This liquid-crystalline conjugated polymer was realized by incorporating intramolecular sulphur–fluorine interactions and bulky side chains linked to a tetrahedral carbon having a large form factor. By optimizing the polymer concentration and themore » flow field, we could achieve a high dichroic ratio of 16.67 in emission from conducting conjugated polymer films. Two-dimensional grazing-incidence X-ray diffraction was performed to analyse a well-defined conjugated polymer alignment. Thin-film transistors built on highly aligned conjugated polymer films showed more than three orders of magnitude faster carrier mobility along the conjugated polymer alignment direction than the perpendicular direction.« less

Challenges and Perspectives for NASICON-Type Electrode Materials for Advanced Sodium-Ion Batteries.

PubMed

Chen, Shuangqiang; Wu, Chao; Shen, Laifa; Zhu, Changbao; Huang, Yuanye; Xi, Kai; Maier, Joachim; Yu, Yan

2017-12-01

Sodium-ion batteries (SIBs) have attracted increasing attention in the past decades, because of high overall abundance of precursors, their even geographical distribution, and low cost. Apart from inherent thermodynamic disadvantages, SIBs have to overcome multiple kinetic problems, such as fast capacity decay, low rate capacities and low Coulombic efficiencies. A special case is sodium super ion conductor (NASICON)-based electrode materials as they exhibit - besides pronounced structural stability - exceptionally high ion conductivity, rendering them most promising for sodium storage. Owing to the limiting, comparatively low electronic conductivity, nano-structuring is a prerequisite for achieving satisfactory rate-capability. In this review, we analyze advantages and disadvantages of NASICON-type electrode materials and highlight electrode structure design principles for obtaining the desired electrochemical performance. Moreover, we give an overview of recent approaches to enhance electrical conductivity and structural stability of cathode and anode materials based on NASICON structure. We believe that this review provides a pertinent insight into relevant design principles and inspires further research in this respect. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

First-principles calculation of electronic and optical properties of graphene like ZnO (G-ZnO)

NASA Astrophysics Data System (ADS)

Farooq, Rabia; Mahmood, Tariq; Anwar, Abdul Waheed; Abbasi, Ghadah Niaz

2016-02-01

Semiconductor metal oxides are favorable for their exotic properties like wide band gap, transparency, enhanced charge mobility, and strong luminescence at room temperature. These properties have put metal oxides under limelight, especially ZnO has earned a renowned position in emanate industry for transparent electrodes, electronics, super-capacitors, photo-voltaic cells, gas-sensors, and many more. ZnO is not only environmental friendly but also a highly stable and cheap photo catalytic source naturally available in high abundance. First principles calculation is performed to study optoelectronic properties of ZnO. Geometry optimization of graphene like ZnO (G-ZnO) is preformed using generalized gradient approximation along with hybrid functional (GGA-PBE and GGA-PBE + U) to calculate various structural and electronic parameters of G-ZnO. Employing Hubbard (U) parameter improved band gap and c/a ratio calculation as 1.245 eV and 1.613 respectively; also dielectric constant is calculated as 4.58 (U = 15 eV) which is in accordance with the available experimental data.

Simultaneous Clostridial fermentation, lipase-catalyzed esterification, and ester extraction to enrich diesel with butyl butyrate.

PubMed

van den Berg, Corjan; Heeres, Arjan S; van der Wielen, Luuk A M; Straathof, Adrie J J

2013-01-01

The recovery of 1-butanol from fermentation broth is energy-intensive since typical concentrations in fermentation broth are below 20 g L(-1). To prevent butanol inhibition and high downstream processing costs, we aimed at producing butyl esters instead of 1-butanol. It is shown that it is possible to perform simultaneously clostridial fermentation, esterification of the formed butanol to butyl butyrate, and extraction of this ester by hexadecane. The very high partition coefficient of butyl butyrate pulls the esterification towards the product side even at fermentation pH and relatively low butanol concentrations. The hexadecane extractant is a model diesel compound and is nontoxic to the cells. If butyl butyrate enriched diesel can directly be used as car fuel, no product recovery is required. A proof-of-principle experiment for the one-pot bio-ester production from glucose led to 5 g L(-1) butyl butyrate in the hexadecane phase. The principle may be extended to a wide range of esters, especially to longer chain ones. Copyright © 2012 Wiley Periodicals, Inc.

The prediction of crystal structure by merging knowledge methods with first principles quantum mechanics

NASA Astrophysics Data System (ADS)

Ceder, Gerbrand

2007-03-01

The prediction of structure is a key problem in computational materials science that forms the platform on which rational materials design can be performed. Finding structure by traditional optimization methods on quantum mechanical energy models is not possible due to the complexity and high dimensionality of the coordinate space. An unusual, but efficient solution to this problem can be obtained by merging ideas from heuristic and ab initio methods: In the same way that scientist build empirical rules by observation of experimental trends, we have developed machine learning approaches that extract knowledge from a large set of experimental information and a database of over 15,000 first principles computations, and used these to rapidly direct accurate quantum mechanical techniques to the lowest energy crystal structure of a material. Knowledge is captured in a Bayesian probability network that relates the probability to find a particular crystal structure at a given composition to structure and energy information at other compositions. We show that this approach is highly efficient in finding the ground states of binary metallic alloys and can be easily generalized to more complex systems.

Design for the Maintainer: Projecting Maintenance Performance from Design Characteristics.

DTIC Science & Technology

1981-07-01

of Kahneman and Tversky (Tversky & Kahneman, 1974; Kahneman & Tversky, 1979). They have observed some general principles to which human decision...makers tend to adhere. The first of these is the "representativeness heuristicw . According to this principle , the question, ’will event A be generated by...process B?", will be decided affirmatively to the extent that the event A resembles process B. According to this principle , if failure in a computer

Acquisition of the novel name-nameless category (N3C) principle by young children who have Down syndrome.

PubMed

Mervis, C B; Bertrand, J

1995-11-01

Acquisition of the novel name-nameless category (N3C) principle by 22 children with Down syndrome between the ages of 2.42 and 3.33 years was examined to investigate the generalizability of a new approach to early lexical development: the developmental lexical principles framework. Results indicated that, as predicted, the N3C principle (operationally defined as the ability to fast map a new word to a [basic level] category), is not available at the start of lexical acquisition. The predicted link between ability to use the N3C principle and ability to perform exhaustive categorization of objects was supported. Children who used the principle had significantly larger productive vocabularies than did those who did not and, according to maternal report, had begun to acquire new words rapidly.

A low-cost photonic biosensor built on a polymer platform

NASA Astrophysics Data System (ADS)

Wang, Linghua; Kodeck, Valérie; Van Vlierberghe, Sandra; Ren, Jun; Teng, Jie; Han, Xiuyou; Jian, Xigao; Baets, Roel; Morthier, Geert; Zhao, Mingshan

2011-12-01

Planar integrated optical biosensors are becoming more and more important as they facilitate label-free and real time monitoring biosensing with high sensitivity. In this paper, the systematic research on one kind of optical biosensor, based on a resonant principle in a polymer ring resonator, will be presented. Reduced footprint and high sensitivity are advantages of this kind of biosensor. Rather than expensive CMOS fabrication, the device with high performance is fabricated through a simple UV based soft imprint technique utilizing self-developed low loss polymer material. The measurement results for the bulk sensing of a NaCl solution and the surface sensing of a minimal amount of avidin molecules in a buffered solution will be presented.

Fresh Slice Self-Seeding and Fresh Slice Harmonic Lasing at LCLS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amann, J.W.

We present results from the successful demonstration of fresh slice self-seeding at the Linac Coherent Light Source (LCLS).* The performance is compared with SASE and regular self-seeding at photon energy of 5.5 keV, resulting in a relative average brightness increase of a factor of 12 and a factor of 2 respectively. Following this proof-of-principle we discuss the forthcoming plans to use the same technique** for fresh slice harmonic lasing in an upcoming experiment. The demonstration of fresh slice harmonic lasing provides an attractive solution for future XFELs aiming to achieve high efficiency, high brightness X-ray pulses at high photon energiesmore » (>12 keV).***« less

The new high field photoexcitation muon spectrometer at the ISIS pulsed neutron and muon source

NASA Astrophysics Data System (ADS)

Yokoyama, K.; Lord, J. S.; Murahari, P.; Wang, K.; Dunstan, D. J.; Waller, S. P.; McPhail, D. J.; Hillier, A. D.; Henson, J.; Harper, M. R.; Heathcote, P.; Drew, A. J.

2016-12-01

A high power pulsed laser system has been installed on the high magnetic field muon spectrometer (HiFi) at the International Science Information Service pulsed neutron and muon source, situated at the STFC Rutherford Appleton Laboratory in the UK. The upgrade enables one to perform light-pump muon-probe experiments under a high magnetic field, which opens new applications of muon spin spectroscopy. In this report we give an overview of the principle of the HiFi laser system and describe the newly developed techniques and devices that enable precisely controlled photoexcitation of samples in the muon instrument. A demonstration experiment illustrates the potential of this unique combination of the photoexcited system and avoided level crossing technique.

The new high field photoexcitation muon spectrometer at the ISIS pulsed neutron and muon source.

PubMed

Yokoyama, K; Lord, J S; Murahari, P; Wang, K; Dunstan, D J; Waller, S P; McPhail, D J; Hillier, A D; Henson, J; Harper, M R; Heathcote, P; Drew, A J

2016-12-01

A high power pulsed laser system has been installed on the high magnetic field muon spectrometer (HiFi) at the International Science Information Service pulsed neutron and muon source, situated at the STFC Rutherford Appleton Laboratory in the UK. The upgrade enables one to perform light-pump muon-probe experiments under a high magnetic field, which opens new applications of muon spin spectroscopy. In this report we give an overview of the principle of the HiFi laser system and describe the newly developed techniques and devices that enable precisely controlled photoexcitation of samples in the muon instrument. A demonstration experiment illustrates the potential of this unique combination of the photoexcited system and avoided level crossing technique.

48 CFR 31.701 - Purpose.

Code of Federal Regulations, 2010 CFR

2010-10-01

... REQUIREMENTS CONTRACT COST PRINCIPLES AND PROCEDURES Contracts With Nonprofit Organizations 31.701 Purpose. This subpart provides the principles for determining the cost applicable to work performed by nonprofit... purposes, of which no part of the net earnings inure to the benefit of any private shareholder or...

37 CFR 385.11 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... a musical work; or (4) Performs the functions of marketing and authorizing the distribution of a... definition of “Service revenue,” and subject to U.S. Generally Accepted Accounting Principles, service... Accepted Accounting Principles, and including for the avoidance of doubt barter or nonmonetary...

48 CFR 852.211-70 - Service data manuals.

Code of Federal Regulations, 2011 CFR

2011-10-01

... applicable, flow charts and narrative descriptions of software shall be provided. If programming is either...) Section IV, Principles of Operation. This section shall describe in narrative form the principles of... the recommended frequency of performance shall be included for visual inspection, cleaning...

Principles of robotics: regulating robots in the real world

NASA Astrophysics Data System (ADS)

Boden, Margaret; Bryson, Joanna; Caldwell, Darwin; Dautenhahn, Kerstin; Edwards, Lilian; Kember, Sarah; Newman, Paul; Parry, Vivienne; Pegman, Geoff; Rodden, Tom; Sorrell, Tom; Wallis, Mick; Whitby, Blay; Winfield, Alan

2017-04-01

This paper proposes a set of five ethical principles, together with seven high-level messages, as a basis for responsible robotics. The Principles of Robotics were drafted in 2010 and published online in 2011. Since then the principles have influenced, and continue to influence, a number of initiatives in robot ethics but have not, to date, been formally published. This paper remedies that omission.

Comparisons of auction mechanisms in a multiple unit setting: A consideration for restructuring electric power markets

NASA Astrophysics Data System (ADS)

Bernard, John Charles

The objective of this study was to compare the performance of five single sided auctions that could be used in restructured electric power markets across different market sizes in a multiple unit setting. Auction selection would profoundly influence an industry over $200 billion in size in the United States, and the consequences of implementing an inappropriate mechanism would be great. Experimental methods were selected to analyze the auctions. Two rounds of experiments were conducted, the first testing the sealed offer last accepted offer (LAO) and first rejected offer (FRO), and the clock English (ENG) and sealed offer English (SOE) in markets of sizes two and six. The FRO, SOE, and ENG used the same pricing rule. Second round testing was on the LAO, FRO, and the nonuniform price multiple unit Vickrey (MUV) in markets of sizes two, four, and six. Experiments lasted 23 and 75 periods for rounds 1 and 2 respectively. Analysis of variance and contrast analysis were used to examine the data. The four performance measures used were price, efficiency, profits per unit, and supply revelation. Five basic principles were also assessed: no sales at losses, all low cost capacity should be offered and sold, no high cost capacity should sell, and the market should clear. It was expected group size and auction type would affect performance. For all performance measures, group size was a significant variable, with smaller groups showing poorer performance. Auction type was significant only for the efficiency performance measure, where clock auctions outperformed the others. Clock auctions also proved superior for the first four principles. The FRO performed poorly in almost all situations, and should not be a preferred mechanism in any market. The ENG was highly efficient, but expensive for the buyer. The SOE appeared superior to the FRO and ENG. The clock improves efficiency over the FRO while less information kept prices under the ENG. The MUV was superior in revealing costs, but performed less well in other categories. While concerns existed for all the mechanisms investigated, the commonly proposed LAO was the best option for restructured electric power markets.

Low Sound Velocity Contributing to the High Thermoelectric Performance of Ag8SnSe6

PubMed Central

Li, Wen; Lin, Siqi; Ge, Binghui; Yang, Jiong; Zhang, Wenqing

2016-01-01

Conventional strategies for advancing thermoelectrics by minimizing the lattice thermal conductivity focus on phonon scattering for a short mean free path. Here, a design of slow phonon propagation as an effective approach for high‐performance thermoelectrics is shown. Taking Ag8SnSe6 as an example, which shows one of the lowest sound velocities among known thermoelectric semiconductors, the lattice thermal conductivity is found to be as low as 0.2 W m−1 K−1 in the entire temperature range. As a result, a peak thermoelectric figure of merit zT > 1.2 and an average zT as high as ≈0.8 are achieved in Nb‐doped materials, without relying on a high thermoelectric power factor. This work demonstrates not only a guiding principle of low sound velocity for minimal lattice thermal conductivity and therefore high zT, but also argyrodite compounds as promising thermoelectric materials with weak chemical bonds and heavy constituent elements. PMID:27980995

Neural network controller development and implementation for spark ignition engines with high EGR levels.

PubMed

Vance, Jonathan Blake; Singh, Atmika; Kaul, Brian C; Jagannathan, Sarangapani; Drallmeier, James A

2007-07-01

Past research has shown substantial reductions in the oxides of nitrogen (NOx) concentrations by using 10%-25% exhaust gas recirculation (EGR) in spark ignition (SI) engines (see Dudek and Sain, 1989). However, under high EGR levels, the engine exhibits strong cyclic dispersion in heat release which may lead to instability and unsatisfactory performance preventing commercial engines to operate with high EGR levels. A neural network (NN)-based output feedback controller is developed to reduce cyclic variation in the heat release under high levels of EGR even when the engine dynamics are unknown by using fuel as the control input. A separate control loop was designed for controlling EGR levels. The stability analysis of the closed-loop system is given and the boundedness of the control input is demonstrated by relaxing separation principle, persistency of excitation condition, certainty equivalence principle, and linear in the unknown parameter assumptions. Online training is used for the adaptive NN and no offline training phase is needed. This online learning feature and model-free approach is used to demonstrate the applicability of the controller on a different engine with minimal effort. Simulation results demonstrate that the cyclic dispersion is reduced significantly using the proposed controller when implemented on an engine model that has been validated experimentally. For a single cylinder research engine fitted with a modern four-valve head (Ricardo engine), experimental results at 15% EGR indicate that cyclic dispersion was reduced 33% by the controller, an improvement of fuel efficiency by 2%, and a 90% drop in NOx from stoichiometric operation without EGR was observed. Moreover, unburned hydrocarbons (uHC) drop by 6% due to NN control as compared to the uncontrolled scenario due to the drop in cyclic dispersion. Similar performance was observed with the controller on a different engine.

Proof-of-principle demonstration of Nb3Sn superconducting radiofrequency cavities for high Q0 applications

NASA Astrophysics Data System (ADS)

Posen, S.; Liepe, M.; Hall, D. L.

2015-02-01

Many future particle accelerators require hundreds of superconducting radiofrequency (SRF) cavities operating with high duty factor. The large dynamic heat load of the cavities causes the cryogenic plant to make up a significant part of the overall cost of the facility. This contribution can be reduced by replacing standard niobium cavities with ones coated with a low-dissipation superconductor such as Nb3Sn. In this paper, we present results for single cell cavities coated with Nb3Sn at Cornell. Five coatings were carried out, showing that at 4.2 K, high Q0 out to medium fields was reproducible, resulting in an average quench field of 14 MV/m and an average 4.2 K Q0 at quench of 8 × 109. In each case, the peak surface magnetic field at quench was well above Hc1, showing that it is not a limiting field in these cavities. The coating with the best performance had a quench field of 17 MV/m, exceeding gradient requirements for state-of-the-art high duty factor SRF accelerators. It is also shown that—taking into account the thermodynamic efficiency of the cryogenic plant—the 4.2 K Q0 values obtained meet the AC power consumption requirements of state-of-the-art high duty factor accelerators, making this a proof-of-principle demonstration for Nb3Sn cavities in future applications.

Environmental Quality Assessment of Built Areas with High Vacancy

NASA Astrophysics Data System (ADS)

Jiang, Y.; Yuan, Y.; Neale, A. C.

2015-12-01

Around the world, many urban areas are challenged by vacant and abandoned residential and business property. High vacancy areas have often been associated with increasing public safety problems and declining property values and subsequent tax base. High vacancy can lead to visible signs of city decline and significant barriers to the revitalization of cities. Addressing the problem of vacancy requires knowledge of vacancy patterns and their possible contributing factors. In this study, we evaluated the ten year (2005-2015) urban environmental changes for some high vacancy areas. Social and economic variables derived from U.S. census data such as non-white population, employment rate, housing price, and environmental variables derived from National Land Cover Data such as land cover and impervious area, were used as the basis for analysis. Correlation analysis and principle components analysis were performed at the Census Block Group level. Three components were identified and interpreted as economic status, urbanness, and greenness. A synthetic Urban Environmental Quality (UEQ) index was developed by integrating the three principle components according to their weights. Comparisons of the UEQ indices between the 2005 and 2015 in the increasingly high vacancy area provided useful information for investigating the possible associations between social, economic, and environmental factors, and the vacancy status. This study could provide useful information for understanding the complex issues leading to vacancy and facilitating future rehabilitation of vacant urban area.

A Missile-Borne Angular Velocity Sensor Based on Triaxial Electromagnetic Induction Coils

PubMed Central

Li, Jian; Wu, Dan; Han, Yan

2016-01-01

Aiming to solve the problem of the limited measuring range for angular motion parameters of high-speed rotating projectiles in the field of guidance and control, a self-adaptive measurement method for angular motion parameters based on the electromagnetic induction principle is proposed. First, a framework with type bent “I-shape” is used to design triaxial coils in a mutually orthogonal way. Under the condition of high rotational speed of a projectile, the induction signal of the projectile moving across a geomagnetic field is acquired by using coils. Second, the frequency of the pulse signal is adjusted self-adaptively. Angular velocity and angular displacement are calculated in the form of periodic pulse counting and pulse accumulation, respectively. Finally, on the basis of that principle prototype of the sensor is researched and developed, performance of measuring angular motion parameters are tested on the sensor by semi-physical and physical simulation experiments, respectively. Experimental results demonstrate that the sensor has a wide measuring range of angular velocity from 1 rps to 100 rps with a measurement error of less than 0.3%, and the angular displacement measurement error is lower than 0.2°. The proposed method satisfies measurement requirements for high-speed rotating projectiles with an extremely high dynamic range of rotational speed and high precision, and has definite value to engineering applications in the fields of attitude determination and geomagnetic navigation. PMID:27706039

A Missile-Borne Angular Velocity Sensor Based on Triaxial Electromagnetic Induction Coils.

PubMed

Li, Jian; Wu, Dan; Han, Yan

2016-09-30

Aiming to solve the problem of the limited measuring range for angular motion parameters of high-speed rotating projectiles in the field of guidance and control, a self-adaptive measurement method for angular motion parameters based on the electromagnetic induction principle is proposed. First, a framework with type bent "I-shape" is used to design triaxial coils in a mutually orthogonal way. Under the condition of high rotational speed of a projectile, the induction signal of the projectile moving across a geomagnetic field is acquired by using coils. Second, the frequency of the pulse signal is adjusted self-adaptively. Angular velocity and angular displacement are calculated in the form of periodic pulse counting and pulse accumulation, respectively. Finally, on the basis of that principle prototype of the sensor is researched and developed, performance of measuring angular motion parameters are tested on the sensor by semi-physical and physical simulation experiments, respectively. Experimental results demonstrate that the sensor has a wide measuring range of angular velocity from 1 rps to 100 rps with a measurement error of less than 0.3%, and the angular displacement measurement error is lower than 0.2°. The proposed method satisfies measurement requirements for high-speed rotating projectiles with an extremely high dynamic range of rotational speed and high precision, and has definite value to engineering applications in the fields of attitude determination and geomagnetic navigation.

Accounting Principles 30G. Interim Guide.

ERIC Educational Resources Information Center

Manitoba Dept. of Education and Training, Winnipeg.

This curriculum guide was developed for a senior-level introductory accounting course for students in high schools in Manitoba. The course introduces Canadian accounting principles and practices; it applies Generally Accepted Accounting Principles (GAAP) to introductory financial accounting. The guide includes the following components: (1) an…

High potential thermoelectric figure of merit in ternary La 3Cu 3X 4 (X = P, As, Sb and Bi) compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pandey, Tribhuwan; Parker, David S.

Here, we investigate the thermoelectric properties of the relatively unexplored rare-earth ternary compounds La 3Cu 3X 4 (X= Bi, Sb, As, and P) using first principles electronic structure and Boltzmann transport calculations. These compounds, of which the La 3Cu 3Sb 4 and La 3Cu 3Bi 4 compounds have previously been synthesized, are all predicted to semiconductors and present a wide range of band gaps varying from 0.23 eV (for the Bi compound) to 0.87 eV (for the P compound). We further find a mixture of light and heavy bands, which results in a high thermoelectric power factor. In addition wemore » find that at high temperatures of 1000 K these compounds exhibit lattice thermal conductivity less than 1 W/m-K. The combination of low thermal conductivity and good transport properties results in a predicted ZT as high as ~1.5 for both La 3Cu 3P 4 and La 3Cu 3As 4, under high p-type doping. This predicted high performance makes these compounds promising candidates for high performance thermoelectric performance and thus merits further experimental investigation.« less

High potential thermoelectric figure of merit in ternary La 3Cu 3X 4 (X = P, As, Sb and Bi) compounds

DOE PAGES

Pandey, Tribhuwan; Parker, David S.

2017-10-27

Here, we investigate the thermoelectric properties of the relatively unexplored rare-earth ternary compounds La 3Cu 3X 4 (X= Bi, Sb, As, and P) using first principles electronic structure and Boltzmann transport calculations. These compounds, of which the La 3Cu 3Sb 4 and La 3Cu 3Bi 4 compounds have previously been synthesized, are all predicted to semiconductors and present a wide range of band gaps varying from 0.23 eV (for the Bi compound) to 0.87 eV (for the P compound). We further find a mixture of light and heavy bands, which results in a high thermoelectric power factor. In addition wemore » find that at high temperatures of 1000 K these compounds exhibit lattice thermal conductivity less than 1 W/m-K. The combination of low thermal conductivity and good transport properties results in a predicted ZT as high as ~1.5 for both La 3Cu 3P 4 and La 3Cu 3As 4, under high p-type doping. This predicted high performance makes these compounds promising candidates for high performance thermoelectric performance and thus merits further experimental investigation.« less

Teaching the EPR Paradox at High School?

ERIC Educational Resources Information Center

Pospiech, Gesche

1999-01-01

Argues the importance of students at university and in the final years of high school gaining an appreciation of the principles of quantum mechanics. Presents the EPR gedanken experiment (thought experiment) as a method of teaching the principles of quantum mechanics. (Author/CCM)

No scanning depth imaging system based on TOF

NASA Astrophysics Data System (ADS)

Sun, Rongchun; Piao, Yan; Wang, Yu; Liu, Shuo

2016-03-01

To quickly obtain a 3D model of real world objects, multi-point ranging is very important. However, the traditional measuring method usually adopts the principle of point by point or line by line measurement, which is too slow and of poor efficiency. In the paper, a no scanning depth imaging system based on TOF (time of flight) was proposed. The system is composed of light source circuit, special infrared image sensor module, processor and controller of image data, data cache circuit, communication circuit, and so on. According to the working principle of the TOF measurement, image sequence was collected by the high-speed CMOS sensor, and the distance information was obtained by identifying phase difference, and the amplitude image was also calculated. Experiments were conducted and the experimental results show that the depth imaging system can achieve no scanning depth imaging function with good performance.

Fully achromatic nulling interferometer (FANI) for high SNR exoplanet characterization

NASA Astrophysics Data System (ADS)

Hénault, François

2015-09-01

Space-borne nulling interferometers have long been considered as the best option for searching and characterizing extrasolar planets located in the habitable zone of their parent stars. Solutions for achieving deep starlight extinction are now numerous and well demonstrated. However they essentially aim at realizing an achromatic central null in order to extinguish the star. In this communication is described a major improvement of the technique, where the achromatization process is extended to the entire fringe pattern. Therefore higher Signal-to-noise ratios (SNR) and appreciable simplification of the detection system should result. The basic principle of this Fully achromatic nulling interferometer (FANI) consists in inserting dispersive elements along the arms of the interferometer. Herein this principle is explained and illustrated by a preliminary optical system design. The typical achievable performance and limitations are discussed and some initial tolerance requirements are also provided.

Mazda's new V-6 gasoline engine and its innovative induction system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hatamura, K.; Morishita, K.; Asanomi, K.

1987-01-01

Mazda succeeded in the development of a new V-type 6-cylinder engine series comprising 2-liter JF naturally aspirated and turbocharged units and also a 3-liter JE naturally aspirated unit. This engine is 60-degree-banked and has 18 valves: two intake valves and one exhaust valve per cylinder. Various techniques, such as High Rigidity Cylinder Block and HLA, are adopted to upgrade quietness and smoothness. The Dynamic Charge Effects system, a combination of inertia and resonance charge effects, is modeled on the principle of two-degree-of-freedom system. The application of this principle helped develop the Induction system that is compatible with the three enginemore » types. The turbocharger adopted on the JF engine is of a twin scroll type to considerably improve power response quality and increase torque at low speed. Triple Port Induction Control System is used to help improve fuel economy and running performance.« less

Measuring Pressure Volume Loops in the Mouse.

PubMed

Townsend, DeWayne

2016-05-02

Understanding the causes and progression of heart disease presents a significant challenge to the biomedical community. The genetic flexibility of the mouse provides great potential to explore cardiac function at the molecular level. The mouse's small size does present some challenges in regards to performing detailed cardiac phenotyping. Miniaturization and other advancements in technology have made many methods of cardiac assessment possible in the mouse. Of these, the simultaneous collection of pressure and volume data provides a detailed picture of cardiac function that is not available through any other modality. Here a detailed procedure for the collection of pressure-volume loop data is described. Included is a discussion of the principles underlying the measurements and the potential sources of error. Anesthetic management and surgical approaches are discussed in great detail as they are both critical to obtaining high quality hemodynamic measurements. The principles of hemodynamic protocol development and relevant aspects of data analysis are also addressed.

Framing tobacco control efforts within an ethical context

PubMed Central

Fox, B

2005-01-01

Public health efforts to promote tobacco control are not performed within a vacuum. They are subject to interpretation and misinterpretation by consumers and policymakers based largely upon the initial framing of the issues. This paper notes how the tobacco industry has established a particular frame that it is the protector of individual rights and that the public health community is trying to eliminate those rights. This paper then shows how the public health community uses metaphors that may unintentionally support this framing and suggests that by reframing public health efforts in accordance with core ethical principles, the public health community can create more positive messages. A public health ethical framework is proposed to examine how the application of the principles can influence the tobacco control movement. Through the increased use of ethics in tobacco control, the public health community may be better positioned to claim the high road as the protector of the public's interests. PMID:16046701

A study of navigation in virtual space

NASA Technical Reports Server (NTRS)

Darken, Rudy; Sibert, John L.; Shumaker, Randy

1994-01-01

In the physical world, man has developed efficient methods for navigation and orientation. These methods are dependent on the high-fidelity stimuli presented by the environment. When placed in a virtual world which cannot offer stimuli of the same quality due to computing constraints and immature technology, tasks requiring the maintenance of position and orientation knowledge become laborious. In this paper, we present a representative set of techniques based on principles of navigation derived from real world analogs including human and avian navigation behavior and cartography. A preliminary classification of virtual worlds is presented based on the size of the world, the density of objects in the world, and the level of activity taking place in the world. We also summarize an informal study we performed to determine how the tools influenced the subjects' navigation strategies and behavior. We conclude that principles extracted from real world navigation aids such as maps can be seen to apply in virtual environments.

Entanglement-Based Machine Learning on a Quantum Computer

NASA Astrophysics Data System (ADS)

Cai, X.-D.; Wu, D.; Su, Z.-E.; Chen, M.-C.; Wang, X.-L.; Li, Li; Liu, N.-L.; Lu, C.-Y.; Pan, J.-W.

2015-03-01

Machine learning, a branch of artificial intelligence, learns from previous experience to optimize performance, which is ubiquitous in various fields such as computer sciences, financial analysis, robotics, and bioinformatics. A challenge is that machine learning with the rapidly growing "big data" could become intractable for classical computers. Recently, quantum machine learning algorithms [Lloyd, Mohseni, and Rebentrost, arXiv.1307.0411] were proposed which could offer an exponential speedup over classical algorithms. Here, we report the first experimental entanglement-based classification of two-, four-, and eight-dimensional vectors to different clusters using a small-scale photonic quantum computer, which are then used to implement supervised and unsupervised machine learning. The results demonstrate the working principle of using quantum computers to manipulate and classify high-dimensional vectors, the core mathematical routine in machine learning. The method can, in principle, be scaled to larger numbers of qubits, and may provide a new route to accelerate machine learning.

Nanoelectronics: Opportunities for future space applications

NASA Technical Reports Server (NTRS)

Frazier, Gary

1995-01-01

Further improvements in the performance of integrated electronics will eventually halt due to practical fundamental limits on our ability to downsize transistors and interconnect wiring. Avoiding these limits requires a revolutionary approach to switching device technology and computing architecture. Nanoelectronics, the technology of exploiting physics on the nanometer scale for computation and communication, attempts to avoid conventional limits by developing new approaches to switching, circuitry, and system integration. This presentation overviews the basic principles that operate on the nanometer scale that can be assembled into practical devices and circuits. Quantum resonant tunneling (RT) is used as the center-piece of the overview since RT devices already operate at high temperature (120 degrees C) and can be scaled, in principle, to a few nanometers in semiconductors. Near- and long-term applications of GaAs and silicon quantum devices are suggested for signal and information processing, memory, optoelectronics, and radio frequency (RF) communication.

Quantifying the biases in metagenome mining for realistic assessment of microbial ecology of naturally fermented foods.

PubMed

Keisam, Santosh; Romi, Wahengbam; Ahmed, Giasuddin; Jeyaram, Kumaraswamy

2016-09-27

Cultivation-independent investigation of microbial ecology is biased by the DNA extraction methods used. We aimed to quantify those biases by comparative analysis of the metagenome mined from four diverse naturally fermented foods (bamboo shoot, milk, fish, soybean) using eight different DNA extraction methods with different cell lysis principles. Our findings revealed that the enzymatic lysis yielded higher eubacterial and yeast metagenomic DNA from the food matrices compared to the widely used chemical and mechanical lysis principles. Further analysis of the bacterial community structure by Illumina MiSeq amplicon sequencing revealed a high recovery of lactic acid bacteria by the enzymatic lysis in all food types. However, Bacillaceae, Acetobacteraceae, Clostridiaceae and Proteobacteria were more abundantly recovered when mechanical and chemical lysis principles were applied. The biases generated due to the differential recovery of operational taxonomic units (OTUs) by different DNA extraction methods including DNA and PCR amplicons mix from different methods have been quantitatively demonstrated here. The different methods shared only 29.9-52.0% of the total OTUs recovered. Although similar comparative research has been performed on other ecological niches, this is the first in-depth investigation of quantifying the biases in metagenome mining from naturally fermented foods.

Wide-Band Circularly Polarized ReflectarrayUsing Graphene-Based Pancharatnam-Berry Phase Unit-Cells for Terahertz Communication.

PubMed

Deng, Li; Zhang, Yuanyuan; Zhu, Jianfeng; Zhang, Chen

2018-06-05

A wide-band and high gain circularly polarized (CP) graphene-based reflectarray operating in the THz regime is proposed and theoretically investigated in this paper. The proposed reflectarray consists of a THz CP source and several graphene-based unit-cells. Taking advantages of the Pancharatnam Berry (PB) phase principle, the graphene-based unit-cell is capable of realizing a tunable phase range of 360° in a wide-band (1.4⁻1.7 THz) by unit-cell rotating, overcoming the restriction of intrinsic narrow-band resonance in graphene. Therefore, this graphene-based unit-cell exhibits superior bandwidth and phase tunability to its previous counterparts. To demonstrate this, a wide-band (1.4⁻1.7 THz) focusing metasurface based on the proposed unit-cell that exhibits excellent focusing effect was designed. Then, according to the reversibility of the optical path, a CP reflectarray was realized by placing a wide-band CP THz source at the focal point of the metasurface. Numerical simulation demonstrates that this reflectarray can achieve a stable high gain up to 15 dBic and an axial ratio around 2.1 dB over the 1.4⁻1.7 THz band. The good radiation performance of the proposed CP reflectarray, as demonstrated, underlines its suitability for the THz communication applications. Moreover, the design principle of this graphene-based reflectarray with a full 360° phase range tunable unit-cells provides a new pathway to design high-performance CP reflectarray in the THz regime.

Applying principles from safety science to improve child protection.

PubMed

Cull, Michael J; Rzepnicki, Tina L; O'Day, Kathryn; Epstein, Richard A

2013-01-01

Child Protective Services Agencies (CPSAs) share many characteristics with other organizations operating in high-risk, high-profile industries. Over the past 50 years, industries as diverse as aviation, nuclear power, and healthcare have applied principles from safety science to improve practice. The current paper describes the rationale, characteristics, and challenges of applying concepts from the safety culture literature to CPSAs. Preliminary efforts to apply key principles aimed at improving child safety and well-being in two states are also presented.

Improving Student Awareness and Performance.

ERIC Educational Resources Information Center

Brown, Dale; Bateman, David N.

1978-01-01

Through the student activities of the Profession and Career Package (PAC), general principles taught in an introductory business course, "Principles of Management," are made relevant to students' future career plans. The development of the PAC approach, its objectives, and student reaction to this method are discussed. (JMD)

Academic Success Through Quality-Managed Course Design.

ERIC Educational Resources Information Center

Reese, Andy C.; Mobley, Mary F.

1996-01-01

Principles of quality management, focusing on defect prevention rather than correction, were applied to the design of a graduate biomedicine course in immunology. The principles require clearly stated course mission and objectives, numerous intermediate steps to achieving objectives, immediate feedback on student performance, and immediate…

Application and Implications of Agent Technology for Librarians.

ERIC Educational Resources Information Center

Nardi, Bonnie A.; O'Day, Vicki L.

1998-01-01

Examines intelligent software agents, presents nine design principles aimed specifically at the technology perspective (to personalize task performance and general principles), and discusses what librarians can do that software agents (agents defined as activity-aware software programs) cannot do. Describes an information ecology that integrates…

Typewriting Methodology 1977: Eight Basic Principles for Good Results

ERIC Educational Resources Information Center

Winger, Fred E.

1977-01-01

The eight basic principles of teaching methodology discussed are as follows: Stress position and technique, stress skill building, stress the pretest/practice/posttest method, stress action research, stress true production skills, stress good proofreading skills, stress performance goals, and stress individualized instruction. (TA)

Delegation: A Competency of Superior Performers?

DTIC Science & Technology

1982-12-01

subordinate, distribution of power and responsibility. Henri Fayol does no better with this subject in his classic fourteen principles of management . He...Structure and Behavior, Litterer, Joseph A., Wiley and Sons, Inc., New York, 1963. 4. Fayol, Henri, "General Principles of Management ", from Classics

Guiding principles of subcutaneous immunotherapy for allergic rhinitis in Japan.

PubMed

Okamoto, Yoshitaka; Ohta, Nobuo; Okano, Mitsuhiro; Kamijo, Atsushi; Gotoh, Minoru; Suzuki, Motohiko; Takeno, Sachio; Terada, Tetsuya; Hanazawa, Toyoyuki; Horiguchi, Shigetoshi; Honda, Kohei; Matsune, Shoji; Yamada, Takechiyo; Yuta, Atsushi; Nakayama, Takeo; Fujieda, Shigeharu

2014-02-01

In anticipation of the development of guidelines for antigen-specific subcutaneous immunotherapy (SCIT), we present recommendations that can serve as guiding principles based on a review of the scientific literature. Clinical questions (CQs) concerning SCIT were prepared. Literature searches for publications between January 1990 and February 2011 were performed in PubMed, the Cochrane Library, and Japana Centra Revuo Medicina Web version 4. Qualified studies were analyzed and the results were evaluated, consolidated, and codified. We present answers for 13 CQs on the indications, methods, effectiveness and mechanisms of SCIT, with evidence-based recommendations. The guiding principles are intended to be applied to children (≤15 years old) and adults (≥16 years old) with allergic rhinitis (AR). These principles can be used by otorhinolaryngologists for diagnosis of AR, evaluation of severity and rhinoscopic findings, performance of antigen challenge tests, and management of systemic anaphylactic reactions associated with SCIT. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

A Lemon Cell Battery for High-Power Applications

ERIC Educational Resources Information Center

Muske, Kenneth R.; Nigh, Christopher W.; Weinstein, Randy D.

2007-01-01

The use of lemon cell battery to run an electric DC motor is demonstrated for chemistry students. This demonstration aids the students in understanding principles behind the design and construction of the lemon cell battery and principles governing the electric DC motor and other basic principles.

Other ways of measuring `Big G'

NASA Astrophysics Data System (ADS)

Rothleitner, Christian

2016-03-01

In 1798, the British scientist Henry Cavendish performed the first laboratory experiment to determine the gravitational force between two massive bodies. From his result, Newton's gravitational constant, G, was calculated. Cavendish's measurement principle was the torsion balance invented by John Michell some 15 years before. During the following two centuries, more than 300 new measurements followed. Although technology - and physics - developed rapidly during this time, surprisingly, most experiments were still based on the same principle. In fact, the most accurate determination of G to date is a measurement based on the torsion balance principle. Despite the fact that G was one of the first fundamental physical constants ever measured, and despite the huge number of experiments performed on it to this day, its CODATA recommended value still has the highest standard measurement uncertainty when compared to other fundamental physical constants. Even more serious is the fact that even measurements based on the same principle often do not overlap within their attributed standard uncertainties. It must be assumed that various experiments are subject to one or more unknown biases. In this talk I will present some alternative experimental setups to the torsion balance which have been performed or proposed to measure G. Although their estimated uncertainties are often higher than most torsion balance experiments, revisiting such ideas is worthwhile. Advances in technology could offer solutions to problems which were previously insurmountable, these solutions could result in lower measurement uncertainties. New measurement principles could also help to uncover hidden systematic effects.

Tin sulfides and tin selenides at ambient and high pressure conditions

NASA Astrophysics Data System (ADS)

Nguyen Cong, Kien; Gonzalez, Joseph; Steele, Brad; Oleynik, Ivan

The application of high pressure promotes unusual chemical bonding in condensed phase resulting in the synthesis of novel materials, which may be recoverable in metastable states at ambient conditions. First-principles evolutionary crystal structure search is performed to explore novel tin sulfide (SnxSy) and tin selenide (SnxSy) crystals with the goal to discover novel photovoltaic and thermoelectric materials. Variable stoichiometry searches at various pressures are performed and the phase diagrams are constructed in the range of pressures 0-100 GPa, which include both the thermodynamically stable and lowest enthalpy metastable structures. Several new structures are identified and their dynamical stability is investigated. To help experimental synthesis of these novel compounds, Raman spectra and XRD patterns are also calculated. These new materials are also investigated to identify those with promising photovoltaic and thermoelectric properties.

Technologies and problems of reengineering of the business processes of company

NASA Astrophysics Data System (ADS)

Silka, Dmitriy

2017-10-01

Management of the combination of business processes is a modern approach in the field of business management. Together with a lot of management approaches business processes allow us to identify all the resultant actions. Article reveals the modern view on the essence of business processes as well as the general approaches of their allocation. Principles of construction and business process re-engineering are proposed. Recommendations on how to perform re-engineering under high cyclic dynamics of business activity are provided.

First Principles Modeling of Structure and Transport in Solid Polymer Electrolytes, Ionic Liquids, and Methanol/Water Mixtures

DTIC Science & Technology

2016-02-10

potential in making high- performance solid state lithium ion batteries [1,2]. Among them, the polyethylene oxide-alkali salts systems PEO6:XPF6 (X = H...electrolytes for magnesium batteries incorporating chloro- or iodo- ionic liquids. Much of this work was done in collaboration with the experimental group...magnesium batteries incorporating chloro- or iodo- ionic liquids. Much of this work was done in collaboration with the experimental group of Prof. Vito Di

High-throughput screening of metal-porphyrin-like graphenes for selective capture of carbon dioxide

PubMed Central

Bae, Hyeonhu; Park, Minwoo; Jang, Byungryul; Kang, Yura; Park, Jinwoo; Lee, Hosik; Chung, Haegeun; Chung, ChiHye; Hong, Suklyun; Kwon, Yongkyung; Yakobson, Boris I.; Lee, Hoonkyung

2016-01-01

Nanostructured materials, such as zeolites and metal-organic frameworks, have been considered to capture CO2. However, their application has been limited largely because they exhibit poor selectivity for flue gases and low capture capacity under low pressures. We perform a high-throughput screening for selective CO2 capture from flue gases by using first principles thermodynamics. We find that elements with empty d orbitals selectively attract CO2 from gaseous mixtures under low CO2 pressures (~10−3 bar) at 300 K and release it at ~450 K. CO2 binding to elements involves hybridization of the metal d orbitals with the CO2 π orbitals and CO2-transition metal complexes were observed in experiments. This result allows us to perform high-throughput screening to discover novel promising CO2 capture materials with empty d orbitals (e.g., Sc– or V–porphyrin-like graphene) and predict their capture performance under various conditions. Moreover, these findings provide physical insights into selective CO2 capture and open a new path to explore CO2 capture materials. PMID:26902156

High-throughput screening of metal-porphyrin-like graphenes for selective capture of carbon dioxide.

PubMed

Bae, Hyeonhu; Park, Minwoo; Jang, Byungryul; Kang, Yura; Park, Jinwoo; Lee, Hosik; Chung, Haegeun; Chung, ChiHye; Hong, Suklyun; Kwon, Yongkyung; Yakobson, Boris I; Lee, Hoonkyung

2016-02-23

Nanostructured materials, such as zeolites and metal-organic frameworks, have been considered to capture CO2. However, their application has been limited largely because they exhibit poor selectivity for flue gases and low capture capacity under low pressures. We perform a high-throughput screening for selective CO2 capture from flue gases by using first principles thermodynamics. We find that elements with empty d orbitals selectively attract CO2 from gaseous mixtures under low CO2 pressures (~10(-3) bar) at 300 K and release it at ~450 K. CO2 binding to elements involves hybridization of the metal d orbitals with the CO2 π orbitals and CO2-transition metal complexes were observed in experiments. This result allows us to perform high-throughput screening to discover novel promising CO2 capture materials with empty d orbitals (e.g., Sc- or V-porphyrin-like graphene) and predict their capture performance under various conditions. Moreover, these findings provide physical insights into selective CO2 capture and open a new path to explore CO2 capture materials.

High-throughput screening of metal-porphyrin-like graphenes for selective capture of carbon dioxide

NASA Astrophysics Data System (ADS)

Bae, Hyeonhu; Park, Minwoo; Jang, Byungryul; Kang, Yura; Park, Jinwoo; Lee, Hosik; Chung, Haegeun; Chung, Chihye; Hong, Suklyun; Kwon, Yongkyung; Yakobson, Boris I.; Lee, Hoonkyung

2016-02-01

Nanostructured materials, such as zeolites and metal-organic frameworks, have been considered to capture CO2. However, their application has been limited largely because they exhibit poor selectivity for flue gases and low capture capacity under low pressures. We perform a high-throughput screening for selective CO2 capture from flue gases by using first principles thermodynamics. We find that elements with empty d orbitals selectively attract CO2 from gaseous mixtures under low CO2 pressures (~10-3 bar) at 300 K and release it at ~450 K. CO2 binding to elements involves hybridization of the metal d orbitals with the CO2 π orbitals and CO2-transition metal complexes were observed in experiments. This result allows us to perform high-throughput screening to discover novel promising CO2 capture materials with empty d orbitals (e.g., Sc- or V-porphyrin-like graphene) and predict their capture performance under various conditions. Moreover, these findings provide physical insights into selective CO2 capture and open a new path to explore CO2 capture materials.

Enhanced scintillation of Ba3In(B3O6)3 based on nitrogen doping

NASA Astrophysics Data System (ADS)

Wang, Z. X.; Pei, H.; Tao, X. M.; Cai, G. M.; Mao, R. H.; Jin, Z. P.

2018-02-01

Scintillating materials, as a class of luminescent materials, are highly demanded for practical use in the high-energy detection. However, the applications are often hampered by their low light yield (LY) or long decay time for many traditional scintillators. In this work, upon nitrogen anion doping, scintillation performance in layered borate Ba3In(B3O6)3 (BIB) has been excellently enhanced with high XEL intensity of ～3 times as large as that of commercial Bi4Ge3O12 (BGO) and ultra-fast fluorescent decay time of ～1.25 ns. To shed light on origins of the intrinsic violet-blue emission, we measured the in-situ vacuum ultraviolet excited (VUV) emission spectra of N-BIB ceramic. Combined with experiments and first principles calculations, the band-gap reduction and donor-acceptor density increasing by nitrogen (N) doping is responsible for the enhancement of scintillation performance for N-doped Ba3In(B3O6)3. Moreover, nitrogen anion doping rather than conventional cation doping is found to be also applicable to other intrinsic luminescent materials for enhancing performance.

Carbon Nanotube Self-Gating Diode and Application in Integrated Circuits.

PubMed

Si, Jia; Liu, Lijun; Wang, Fanglin; Zhang, Zhiyong; Peng, Lian-Mao

2016-07-26

A nano self-gating diode (SGD) based on nanoscale semiconducting material is proposed, simulated, and realized on semiconducting carbon nanotubes (CNTs) through a doping-free fabrication process. The relationships between the performance and material/structural parameters of the SGD are explored through numerical simulation and verified by experiment results. Based on these results, performance optimization strategy is outlined, and high performance CNT SGDs are fabricated and demonstrated to surpass other published CNT diodes. In particular the CNT SGD exhibits high rectifier factor of up to 1.4 × 10(6) while retains large on-state current. Benefiting from high yield and stability, CNT SGDs are used for constructing logic and analog integrated circuits. Two kinds of basic digital gates (AND and OR) have been realized on chip through using CNT SGDs and on-chip Ti wire resistances, and a full wave rectifier circuit has been demonstrated through using two CNT SGDs. Although demonstrated here using CNT SGDs, this device structure may in principle be implemented using other semiconducting nanomaterials, to provide ideas and building blocks for electronic applications based on nanoscale materials.

Control performances of a piezoactuator direct drive valve system at high temperatures with thermal insulation

NASA Astrophysics Data System (ADS)

Han, Yung-Min; Han, Chulhee; Kim, Wan Ho; Seong, Ho Yong; Choi, Seung-Bok

2016-09-01

This technical note presents control performances of a piezoactuator direct drive valve (PDDV) operated at high temperature environment. After briefly discussing operating principle and mechanical dimensions of the proposed PDDV, an appropriate size of the PDDV is manufactured. As a first step, the temperature effect on the valve performance is experimentally investigated by measuring the spool displacement at various temperatures. Subsequently, the PDDV is thermally insulated using aerogel and installed in a large-size heat chamber in which the pneumatic-hydraulic cylinders and sensors are equipped. A proportional-integral-derivative feedback controller is then designed and implemented to control the spool displacement of the valve system. In this work, the spool displacement is chosen as a control variable since it is directly related to the flow rate of the valve system. Three different sinusoidal displacements with different frequencies of 1, 10 and 50 Hz are used as reference spool displacement and tracking controls are undertaken up to 150 °C. It is shown that the proposed PDDV with the thermal insulation can provide favorable control responses without significant tracking errors at high temperatures.

What are the effects of sleep deprivation and fatigue in surgical practice?

PubMed

Sugden, Colin; Athanasiou, Thanos; Darzi, Ara

2012-01-01

Sleep deprivation and fatigue have long been linked with accidents in high-risk industries and serious errors in the medical profession, but their effects on surgical performance are less well understood. This article outlines the important functions that human sleep serves and describes the neurobehavioral effects of wakefulness extension and mental fatigue that are relevant to surgical performance, including attentional failure, risk taking, and decision-making bias. Methods used to explore the effects of sleep deprivation and fatigue on surgical performance, from laboratory studies to outcomes data, are discussed; the findings are summarized; and important deficiencies in the literature are highlighted. Future strategies to mitigate performance decline, such as novel assessment tools and countermeasures with proven efficacy, are presented, and their deployment is discussed in the context of key ethical principles. Copyright © 2012 Elsevier Inc. All rights reserved.

Prediction of the High Thermoelectric Performance of Pnictogen Dichalcogenide Layered Compounds with Quasi-One-Dimensional Gapped Dirac-like Band Dispersion

NASA Astrophysics Data System (ADS)

Ochi, Masayuki; Usui, Hidetomo; Kuroki, Kazuhiko

2017-12-01

Thermoelectric power generation has been recognized as one of the most important technologies, and high-performance thermoelectric materials have long been pursued. However, because of the large number of candidate materials, this quest is extremely challenging, and it has become clear that a firm theoretical concept from the viewpoint of band-structure engineering is needed. We theoretically demonstrate that pnictogen dichalcogenide layered compounds, which originally attracted attention as a family of superconductors and have recently been investigated as thermoelectric materials, can exhibit very high thermoelectric performance with elemental substitution. Specifically, we clarify a promising guiding principle for material design and find that LaOAsSe2, a material that has yet to be synthesized, has a power factor that is 6 times as large as that of the known compound LaOBiS2 and can exhibit a very large Z T under some plausible assumptions. This large enhancement of the thermoelectric performance originates from the quasi-one-dimensional gapped Dirac-like band dispersion, which is realized by the square-lattice network. We offer one ideal limit of the band structure for thermoelectric materials. Because our target materials have high controllability of constituent elements and feasibility of carrier doping, experimental studies along this line are eagerly awaited.

[The surgeon and deontology].

PubMed

Sucila, Antanas

2002-01-01

The aim of study is to recall surgeons deontological principles and errors. The article demonstrates some specific deontological errors, performed by surgeon on patients and his colleagues; points out painful sequela of these errors as well. CONCLUSION. The surgeon should take in account deontological principles rigorously in routine daily practice.

Hospital employs TQM principles to rework its evaluation system.

PubMed

Burda, D

1992-02-24

One Kansas hospital has taken the traditional employee evaluation process--with all its performance criteria, point systems and rankings--and turned it on its head. The new system employs total quality management principles and promotes personal development, education and teamwork. And everyone gets the same raise.

Advances in first-principles calculations of thermodynamic properties of planetary materials (Invited)

NASA Astrophysics Data System (ADS)

Wilson, H. F.

2013-12-01

First-principles atomistic simulation is a vital tool for understanding the properties of materials at the high-pressure high-temperature conditions prevalent in giant planet interiors, but properties such as solubility and phase boundaries are dependent on entropy, a quantity not directly accessible in simulation. Determining entropic properties from atomistic simulations is a difficult problem typically requiring a time-consuming integration over molecular dynamics trajectories. Here I will describe recent advances in first-principles thermodynamic calculations which substantially increase the simplicity and efficiency of thermodynamic integration and make entropic properties more readily accessible. I will also describe the use of first-principles thermodynamic calculations for understanding problems including core solubility in gas giants and superionic phase changes in ice giants, as well as future prospects for combining first-principles thermodynamics with planetary-scale models to help us understand the origin and consequences of compositional inhomogeneity in giant planet interiors.

International Conference on the Mechanical Technology of Inertial Devices, University of Newcastle-upon-Tyne, England, Apr. 7-9, 1987, Proceedings

NASA Astrophysics Data System (ADS)

Various papers on the mechanical technology of inertial devices are presented. The topics addressed include: development of a directional gyroscope for remotely piloted vehicles and similar applications; a two-degree-of-freedom gyroscope with frictionless inner and outer gimbal pickoffs; oscillogyro design, manufacture, and performance; development of miniature two-axis rate gyroscope; mechanical design aspects of the electrostatically suspended gyroscope; role of gas-lubricated bearings in current and future sensors; development of a new microporous retainer material for precision ball bearings; design study for a high-stability, large-centrifuge test bed; evaluation of a two-axis rate gyro; operating principles of a two-axis angular rate transducer; and nutation frequency analysis. Also considered are: triaxial laser gyro; mechanical design considerations for a ring laser gyro dither mechanism; environmental considerations in the design of fiberoptic gyroscopes; manufacturing aspects of some critical high-precision mechanical components of inertial devices; dynamics and control of a gyroscopic force measurement system; high precision and high performance motion systems; use of multiple acceleration references to obtain high precision centrifuge data at low cost; gyro testing and evaluation at the Communications Research Centre; review of the mechanical design and development of a high-performance accelerometer; and silicon microengineering for accelerometers.

Patterns of anterior and posterior muscle chain interactions during high performance long-hang elements in gymnastics.

PubMed

von Laßberg, Christoph; Rapp, Walter; Krug, Jürgen

2014-06-01

In a prior study with high level gymnasts we could demonstrate that the neuromuscular activation pattern during the "whip-like" leg acceleration phases (LAP) in accelerating movement sequences on high bar, primarily runs in a consecutive succession from the bar (punctum fixum) to the legs (punctum mobile). The current study presents how the neuromuscular activation is represented during movement sequences that immediately follow the LAP by the antagonist muscle chain to generate an effective transfer of momentum for performing specific elements, based on the energy generated by the preceding LAP. Thirteen high level gymnasts were assessed by surface electromyography during high performance elements on high bar and parallel bars. The results show that the neuromuscular succession runs primarily from punctum mobile towards punctum fixum for generating the transfer of momentum. Additionally, further principles of neuromuscular interactions between the anterior and posterior muscle chain during such movement sequences are presented. The findings complement the understanding of neuromuscular activation patterns during rotational movements around fixed axes and will help to form the basis of more direct and better teaching methods regarding earlier optimization and facilitation of the motor learning process concerning fundamental movement requirements. Copyright © 2014 Elsevier Ltd. All rights reserved.

A 3D Bioprinted Model for the Study of Premalignant Breast Disease

DTIC Science & Technology

2017-05-01

these glands and performed proof-of-principle 3D printing . We have printed simple ductal structures (tubes) and seeded breast epithelial cells. The...performed proof-of-principle 3D printing . We have printed simple ductal structures (tubes) and seeded breast epithelial cells. The next year we will...All of the PN17 reconstruction data from the 5 completed strains has also been sent to the University of Pittsburg for 3D printing . A summary of the

PubMed on Tap: discovering design principles for online information delivery to handheld computers.

PubMed

Hauser, Susan E; Demner-Fushman, Dina; Ford, Glenn; Thoma, George R

2004-01-01

Online access to biomedical information from handheld computers will be a valuable adjunct to other popular medical applications if information delivery systems are designed with handheld computers in mind. The goal of this project is to discover design principles to facilitate practitioners' access to online medical information at the point-of-care. A prototype system was developed to serve as a testbed for this research. Using the testbed, an initial evaluation has yielded several user interface design principles. Continued research is expected to discover additional user interface design principles as well as guidelines for results organization and system performance

High-Efficiency Photovoltaic System Using Partially-Connected DC-DC Converter

NASA Astrophysics Data System (ADS)

Uno, Masatoshi; Kukita, Akio; Tanaka, Koji

Power conversion electronics for photovoltaic (PV) systems are desired to operate as efficiently as possible to exploit the power generated by PV modules. This paper proposes a novel PV system in which a dc-dc converter is partially connected to series-connected PV modules. The proposed system achieves high power-conversion efficiency by reducing the passing power and input/output voltages of the converter. The theoretical operating principle was experimentally validated. Resultant efficiency performances of the proposed and conventional systems demonstrated that the proposed system was more efficient in terms of power conversion though the identical converter was used for the both systems.

Overview of the JET results in support to ITER

NASA Astrophysics Data System (ADS)

Litaudon, X.; Abduallev, S.; Abhangi, M.; Abreu, P.; Afzal, M.; Aggarwal, K. M.; Ahlgren, T.; Ahn, J. H.; Aho-Mantila, L.; Aiba, N.; Airila, M.; Albanese, R.; Aldred, V.; Alegre, D.; Alessi, E.; Aleynikov, P.; Alfier, A.; Alkseev, A.; Allinson, M.; Alper, B.; Alves, E.; Ambrosino, G.; Ambrosino, R.; Amicucci, L.; Amosov, V.; Andersson Sundén, E.; Angelone, M.; Anghel, M.; Angioni, C.; Appel, L.; Appelbee, C.; Arena, P.; Ariola, M.; Arnichand, H.; Arshad, S.; Ash, A.; Ashikawa, N.; Aslanyan, V.; Asunta, O.; Auriemma, F.; Austin, Y.; Avotina, L.; Axton, M. D.; Ayres, C.; Bacharis, M.; Baciero, A.; Baião, D.; Bailey, S.; Baker, A.; Balboa, I.; Balden, M.; Balshaw, N.; Bament, R.; Banks, J. W.; Baranov, Y. F.; Barnard, M. A.; Barnes, D.; Barnes, M.; Barnsley, R.; Baron Wiechec, A.; Barrera Orte, L.; Baruzzo, M.; Basiuk, V.; Bassan, M.; Bastow, R.; Batista, A.; Batistoni, P.; Baughan, R.; Bauvir, B.; Baylor, L.; Bazylev, B.; Beal, J.; Beaumont, P. S.; Beckers, M.; Beckett, B.; Becoulet, A.; Bekris, N.; Beldishevski, M.; Bell, K.; Belli, F.; Bellinger, M.; Belonohy, É.; Ben Ayed, N.; Benterman, N. A.; Bergsåker, H.; Bernardo, J.; Bernert, M.; Berry, M.; Bertalot, L.; Besliu, C.; Beurskens, M.; Bieg, B.; Bielecki, J.; Biewer, T.; Bigi, M.; Bílková, P.; Binda, F.; Bisoffi, A.; Bizarro, J. P. S.; Björkas, C.; Blackburn, J.; Blackman, K.; Blackman, T. R.; Blanchard, P.; Blatchford, P.; Bobkov, V.; Boboc, A.; Bodnár, G.; Bogar, O.; Bolshakova, I.; Bolzonella, T.; Bonanomi, N.; Bonelli, F.; Boom, J.; Booth, J.; Borba, D.; Borodin, D.; Borodkina, I.; Botrugno, A.; Bottereau, C.; Boulting, P.; Bourdelle, C.; Bowden, M.; Bower, C.; Bowman, C.; Boyce, T.; Boyd, C.; Boyer, H. J.; Bradshaw, J. M. A.; Braic, V.; Bravanec, R.; Breizman, B.; Bremond, S.; Brennan, P. D.; Breton, S.; Brett, A.; Brezinsek, S.; Bright, M. D. J.; Brix, M.; Broeckx, W.; Brombin, M.; Brosławski, A.; Brown, D. P. D.; Brown, M.; Bruno, E.; Bucalossi, J.; Buch, J.; Buchanan, J.; Buckley, M. A.; Budny, R.; Bufferand, H.; Bulman, M.; Bulmer, N.; Bunting, P.; Buratti, P.; Burckhart, A.; Buscarino, A.; Busse, A.; Butler, N. K.; Bykov, I.; Byrne, J.; Cahyna, P.; Calabrò, G.; Calvo, I.; Camenen, Y.; Camp, P.; Campling, D. C.; Cane, J.; Cannas, B.; Capel, A. J.; Card, P. J.; Cardinali, A.; Carman, P.; Carr, M.; Carralero, D.; Carraro, L.; Carvalho, B. B.; Carvalho, I.; Carvalho, P.; Casson, F. J.; Castaldo, C.; Catarino, N.; Caumont, J.; Causa, F.; Cavazzana, R.; Cave-Ayland, K.; Cavinato, M.; Cecconello, M.; Ceccuzzi, S.; Cecil, E.; Cenedese, A.; Cesario, R.; Challis, C. D.; Chandler, M.; Chandra, D.; Chang, C. S.; Chankin, A.; Chapman, I. T.; Chapman, S. C.; Chernyshova, M.; Chitarin, G.; Ciraolo, G.; Ciric, D.; Citrin, J.; Clairet, F.; Clark, E.; Clark, M.; Clarkson, R.; Clatworthy, D.; Clements, C.; Cleverly, M.; Coad, J. P.; Coates, P. A.; Cobalt, A.; Coccorese, V.; Cocilovo, V.; Coda, S.; Coelho, R.; Coenen, J. W.; Coffey, I.; Colas, L.; Collins, S.; Conka, D.; Conroy, S.; Conway, N.; Coombs, D.; Cooper, D.; Cooper, S. R.; Corradino, C.; Corre, Y.; Corrigan, G.; Cortes, S.; Coster, D.; Couchman, A. S.; Cox, M. P.; Craciunescu, T.; Cramp, S.; Craven, R.; Crisanti, F.; Croci, G.; Croft, D.; Crombé, K.; Crowe, R.; Cruz, N.; Cseh, G.; Cufar, A.; Cullen, A.; Curuia, M.; Czarnecka, A.; Dabirikhah, H.; Dalgliesh, P.; Dalley, S.; Dankowski, J.; Darrow, D.; Davies, O.; Davis, W.; Day, C.; Day, I. E.; De Bock, M.; de Castro, A.; de la Cal, E.; de la Luna, E.; De Masi, G.; de Pablos, J. L.; De Temmerman, G.; De Tommasi, G.; de Vries, P.; Deakin, K.; Deane, J.; Degli Agostini, F.; Dejarnac, R.; Delabie, E.; den Harder, N.; Dendy, R. O.; Denis, J.; Denner, P.; Devaux, S.; Devynck, P.; Di Maio, F.; Di Siena, A.; Di Troia, C.; Dinca, P.; D'Inca, R.; Ding, B.; Dittmar, T.; Doerk, H.; Doerner, R. P.; Donné, T.; Dorling, S. E.; Dormido-Canto, S.; Doswon, S.; Douai, D.; Doyle, P. T.; Drenik, A.; Drewelow, P.; Drews, P.; Duckworth, Ph.; Dumont, R.; Dumortier, P.; Dunai, D.; Dunne, M.; Ďuran, I.; Durodié, F.; Dutta, P.; Duval, B. P.; Dux, R.; Dylst, K.; Dzysiuk, N.; Edappala, P. V.; Edmond, J.; Edwards, A. M.; Edwards, J.; Eich, Th.; Ekedahl, A.; El-Jorf, R.; Elsmore, C. G.; Enachescu, M.; Ericsson, G.; Eriksson, F.; Eriksson, J.; Eriksson, L. G.; Esposito, B.; Esquembri, S.; Esser, H. G.; Esteve, D.; Evans, B.; Evans, G. E.; Evison, G.; Ewart, G. D.; Fagan, D.; Faitsch, M.; Falie, D.; Fanni, A.; Fasoli, A.; Faustin, J. M.; Fawlk, N.; Fazendeiro, L.; Fedorczak, N.; Felton, R. C.; Fenton, K.; Fernades, A.; Fernandes, H.; Ferreira, J.; Fessey, J. A.; Février, O.; Ficker, O.; Field, A.; Fietz, S.; Figueiredo, A.; Figueiredo, J.; Fil, A.; Finburg, P.; Firdaouss, M.; Fischer, U.; Fittill, L.; Fitzgerald, M.; Flammini, D.; Flanagan, J.; Fleming, C.; Flinders, K.; Fonnesu, N.; Fontdecaba, J. M.; Formisano, A.; Forsythe, L.; Fortuna, L.; Fortuna-Zalesna, E.; Fortune, M.; Foster, S.; Franke, T.; Franklin, T.; Frasca, M.; Frassinetti, L.; Freisinger, M.; Fresa, R.; Frigione, D.; Fuchs, V.; Fuller, D.; Futatani, S.; Fyvie, J.; Gál, K.; Galassi, D.; Gałązka, K.; Galdon-Quiroga, J.; Gallagher, J.; Gallart, D.; Galvão, R.; Gao, X.; Gao, Y.; Garcia, J.; Garcia-Carrasco, A.; García-Muñoz, M.; Gardarein, J.-L.; Garzotti, L.; Gaudio, P.; Gauthier, E.; Gear, D. F.; Gee, S. J.; Geiger, B.; Gelfusa, M.; Gerasimov, S.; Gervasini, G.; Gethins, M.; Ghani, Z.; Ghate, M.; Gherendi, M.; Giacalone, J. C.; Giacomelli, L.; Gibson, C. S.; Giegerich, T.; Gil, C.; Gil, L.; Gilligan, S.; Gin, D.; Giovannozzi, E.; Girardo, J. B.; Giroud, C.; Giruzzi, G.; Glöggler, S.; Godwin, J.; Goff, J.; Gohil, P.; Goloborod'ko, V.; Gomes, R.; Gonçalves, B.; Goniche, M.; Goodliffe, M.; Goodyear, A.; Gorini, G.; Gosk, M.; Goulding, R.; Goussarov, A.; Gowland, R.; Graham, B.; Graham, M. E.; Graves, J. P.; Grazier, N.; Grazier, P.; Green, N. R.; Greuner, H.; Grierson, B.; Griph, F. S.; Grisolia, C.; Grist, D.; Groth, M.; Grove, R.; Grundy, C. N.; Grzonka, J.; Guard, D.; Guérard, C.; Guillemaut, C.; Guirlet, R.; Gurl, C.; Utoh, H. H.; Hackett, L. J.; Hacquin, S.; Hagar, A.; Hager, R.; Hakola, A.; Halitovs, M.; Hall, S. J.; Hallworth Cook, S. P.; Hamlyn-Harris, C.; Hammond, K.; Harrington, C.; Harrison, J.; Harting, D.; Hasenbeck, F.; Hatano, Y.; Hatch, D. R.; Haupt, T. D. V.; Hawes, J.; Hawkes, N. C.; Hawkins, J.; Hawkins, P.; Haydon, P. W.; Hayter, N.; Hazel, S.; Heesterman, P. J. L.; Heinola, K.; Hellesen, C.; Hellsten, T.; Helou, W.; Hemming, O. N.; Hender, T. C.; Henderson, M.; Henderson, S. S.; Henriques, R.; Hepple, D.; Hermon, G.; Hertout, P.; Hidalgo, C.; Highcock, E. G.; Hill, M.; Hillairet, J.; Hillesheim, J.; Hillis, D.; Hizanidis, K.; Hjalmarsson, A.; Hobirk, J.; Hodille, E.; Hogben, C. H. A.; Hogeweij, G. M. D.; Hollingsworth, A.; Hollis, S.; Homfray, D. A.; Horáček, J.; Hornung, G.; Horton, A. R.; Horton, L. D.; Horvath, L.; Hotchin, S. P.; Hough, M. R.; Howarth, P. J.; Hubbard, A.; Huber, A.; Huber, V.; Huddleston, T. M.; Hughes, M.; Huijsmans, G. T. A.; Hunter, C. L.; Huynh, P.; Hynes, A. M.; Iglesias, D.; Imazawa, N.; Imbeaux, F.; Imríšek, M.; Incelli, M.; Innocente, P.; Irishkin, M.; Ivanova-Stanik, I.; Jachmich, S.; Jacobsen, A. S.; Jacquet, P.; Jansons, J.; Jardin, A.; Järvinen, A.; Jaulmes, F.; Jednoróg, S.; Jenkins, I.; Jeong, C.; Jepu, I.; Joffrin, E.; Johnson, R.; Johnson, T.; Johnston, Jane; Joita, L.; Jones, G.; Jones, T. T. C.; Hoshino, K. K.; Kallenbach, A.; Kamiya, K.; Kaniewski, J.; Kantor, A.; Kappatou, A.; Karhunen, J.; Karkinsky, D.; Karnowska, I.; Kaufman, M.; Kaveney, G.; Kazakov, Y.; Kazantzidis, V.; Keeling, D. L.; Keenan, T.; Keep, J.; Kempenaars, M.; Kennedy, C.; Kenny, D.; Kent, J.; Kent, O. N.; Khilkevich, E.; Kim, H. T.; Kim, H. S.; Kinch, A.; king, C.; King, D.; King, R. F.; Kinna, D. J.; Kiptily, V.; Kirk, A.; Kirov, K.; Kirschner, A.; Kizane, G.; Klepper, C.; Klix, A.; Knight, P.; Knipe, S. J.; Knott, S.; Kobuchi, T.; Köchl, F.; Kocsis, G.; Kodeli, I.; Kogan, L.; Kogut, D.; Koivuranta, S.; Kominis, Y.; Köppen, M.; Kos, B.; Koskela, T.; Koslowski, H. R.; Koubiti, M.; Kovari, M.; Kowalska-Strzęciwilk, E.; Krasilnikov, A.; Krasilnikov, V.; Krawczyk, N.; Kresina, M.; Krieger, K.; Krivska, A.; Kruezi, U.; Książek, I.; Kukushkin, A.; Kundu, A.; Kurki-Suonio, T.; Kwak, S.; Kwiatkowski, R.; Kwon, O. J.; Laguardia, L.; Lahtinen, A.; Laing, A.; Lam, N.; Lambertz, H. T.; Lane, C.; Lang, P. T.; Lanthaler, S.; Lapins, J.; Lasa, A.; Last, J. R.; Łaszyńska, E.; Lawless, R.; Lawson, A.; Lawson, K. D.; Lazaros, A.; Lazzaro, E.; Leddy, J.; Lee, S.; Lefebvre, X.; Leggate, H. J.; Lehmann, J.; Lehnen, M.; Leichtle, D.; Leichuer, P.; Leipold, F.; Lengar, I.; Lennholm, M.; Lerche, E.; Lescinskis, A.; Lesnoj, S.; Letellier, E.; Leyland, M.; Leysen, W.; Li, L.; Liang, Y.; Likonen, J.; Linke, J.; Linsmeier, Ch.; Lipschultz, B.; Liu, G.; Liu, Y.; Lo Schiavo, V. P.; Loarer, T.; Loarte, A.; Lobel, R. C.; Lomanowski, B.; Lomas, P. J.; Lönnroth, J.; López, J. M.; López-Razola, J.; Lorenzini, R.; Losada, U.; Lovell, J. J.; Loving, A. B.; Lowry, C.; Luce, T.; Lucock, R. M. A.; Lukin, A.; Luna, C.; Lungaroni, M.; Lungu, C. P.; Lungu, M.; Lunniss, A.; Lupelli, I.; Lyssoivan, A.; Macdonald, N.; Macheta, P.; Maczewa, K.; Magesh, B.; Maget, P.; Maggi, C.; Maier, H.; Mailloux, J.; Makkonen, T.; Makwana, R.; Malaquias, A.; Malizia, A.; Manas, P.; Manning, A.; Manso, M. E.; Mantica, P.; Mantsinen, M.; Manzanares, A.; Maquet, Ph.; Marandet, Y.; Marcenko, N.; Marchetto, C.; Marchuk, O.; Marinelli, M.; Marinucci, M.; Markovič, T.; Marocco, D.; Marot, L.; Marren, C. A.; Marshal, R.; Martin, A.; Martin, Y.; Martín de Aguilera, A.; Martínez, F. J.; Martín-Solís, J. R.; Martynova, Y.; Maruyama, S.; Masiello, A.; Maslov, M.; Matejcik, S.; Mattei, M.; Matthews, G. F.; Maviglia, F.; Mayer, M.; Mayoral, M. L.; May-Smith, T.; Mazon, D.; Mazzotta, C.; McAdams, R.; McCarthy, P. J.; McClements, K. G.; McCormack, O.; McCullen, P. A.; McDonald, D.; McIntosh, S.; McKean, R.; McKehon, J.; Meadows, R. C.; Meakins, A.; Medina, F.; Medland, M.; Medley, S.; Meigh, S.; Meigs, A. G.; Meisl, G.; Meitner, S.; Meneses, L.; Menmuir, S.; Mergia, K.; Merrigan, I. R.; Mertens, Ph.; Meshchaninov, S.; Messiaen, A.; Meyer, H.; Mianowski, S.; Michling, R.; Middleton-Gear, D.; Miettunen, J.; Militello, F.; Militello-Asp, E.; Miloshevsky, G.; Mink, F.; Minucci, S.; Miyoshi, Y.; Mlynář, J.; Molina, D.; Monakhov, I.; Moneti, M.; Mooney, R.; Moradi, S.; Mordijck, S.; Moreira, L.; Moreno, R.; Moro, F.; Morris, A. W.; Morris, J.; Moser, L.; Mosher, S.; Moulton, D.; Murari, A.; Muraro, A.; Murphy, S.; Asakura, N. N.; Na, Y. S.; Nabais, F.; Naish, R.; Nakano, T.; Nardon, E.; Naulin, V.; Nave, M. F. F.; Nedzelski, I.; Nemtsev, G.; Nespoli, F.; Neto, A.; Neu, R.; Neverov, V. S.; Newman, M.; Nicholls, K. J.; Nicolas, T.; Nielsen, A. H.; Nielsen, P.; Nilsson, E.; Nishijima, D.; Noble, C.; Nocente, M.; Nodwell, D.; Nordlund, K.; Nordman, H.; Nouailletas, R.; Nunes, I.; Oberkofler, M.; Odupitan, T.; Ogawa, M. T.; O'Gorman, T.; Okabayashi, M.; Olney, R.; Omolayo, O.; O'Mullane, M.; Ongena, J.; Orsitto, F.; Orszagh, J.; Oswuigwe, B. I.; Otin, R.; Owen, A.; Paccagnella, R.; Pace, N.; Pacella, D.; Packer, L. W.; Page, A.; Pajuste, E.; Palazzo, S.; Pamela, S.; Panja, S.; Papp, P.; Paprok, R.; Parail, V.; Park, M.; Parra Diaz, F.; Parsons, M.; Pasqualotto, R.; Patel, A.; Pathak, S.; Paton, D.; Patten, H.; Pau, A.; Pawelec, E.; Soldan, C. Paz; Peackoc, A.; Pearson, I. J.; Pehkonen, S.-P.; Peluso, E.; Penot, C.; Pereira, A.; Pereira, R.; Pereira Puglia, P. P.; Perez von Thun, C.; Peruzzo, S.; Peschanyi, S.; Peterka, M.; Petersson, P.; Petravich, G.; Petre, A.; Petrella, N.; Petržilka, V.; Peysson, Y.; Pfefferlé, D.; Philipps, V.; Pillon, M.; Pintsuk, G.; Piovesan, P.; Pires dos Reis, A.; Piron, L.; Pironti, A.; Pisano, F.; Pitts, R.; Pizzo, F.; Plyusnin, V.; Pomaro, N.; Pompilian, O. G.; Pool, P. J.; Popovichev, S.; Porfiri, M. T.; Porosnicu, C.; Porton, M.; Possnert, G.; Potzel, S.; Powell, T.; Pozzi, J.; Prajapati, V.; Prakash, R.; Prestopino, G.; Price, D.; Price, M.; Price, R.; Prior, P.; Proudfoot, R.; Pucella, G.; Puglia, P.; Puiatti, M. E.; Pulley, D.; Purahoo, K.; Pütterich, Th.; Rachlew, E.; Rack, M.; Ragona, R.; Rainford, M. S. J.; Rakha, A.; Ramogida, G.; Ranjan, S.; Rapson, C. J.; Rasmussen, J. J.; Rathod, K.; Rattá, G.; Ratynskaia, S.; Ravera, G.; Rayner, C.; Rebai, M.; Reece, D.; Reed, A.; Réfy, D.; Regan, B.; Regaña, J.; Reich, M.; Reid, N.; Reimold, F.; Reinhart, M.; Reinke, M.; Reiser, D.; Rendell, D.; Reux, C.; Reyes Cortes, S. D. A.; Reynolds, S.; Riccardo, V.; Richardson, N.; Riddle, K.; Rigamonti, D.; Rimini, F. G.; Risner, J.; Riva, M.; Roach, C.; Robins, R. J.; Robinson, S. A.; Robinson, T.; Robson, D. W.; Roccella, R.; Rodionov, R.; Rodrigues, P.; Rodriguez, J.; Rohde, V.; Romanelli, F.; Romanelli, M.; Romanelli, S.; Romazanov, J.; Rowe, S.; Rubel, M.; Rubinacci, G.; Rubino, G.; Ruchko, L.; Ruiz, M.; Ruset, C.; Rzadkiewicz, J.; Saarelma, S.; Sabot, R.; Safi, E.; Sagar, P.; Saibene, G.; Saint-Laurent, F.; Salewski, M.; Salmi, A.; Salmon, R.; Salzedas, F.; Samaddar, D.; Samm, U.; Sandiford, D.; Santa, P.; Santala, M. I. K.; Santos, B.; Santucci, A.; Sartori, F.; Sartori, R.; Sauter, O.; Scannell, R.; Schlummer, T.; Schmid, K.; Schmidt, V.; Schmuck, S.; Schneider, M.; Schöpf, K.; Schwörer, D.; Scott, S. D.; Sergienko, G.; Sertoli, M.; Shabbir, A.; Sharapov, S. E.; Shaw, A.; Shaw, R.; Sheikh, H.; Shepherd, A.; Shevelev, A.; Shumack, A.; Sias, G.; Sibbald, M.; Sieglin, B.; Silburn, S.; Silva, A.; Silva, C.; Simmons, P. A.; Simpson, J.; Simpson-Hutchinson, J.; Sinha, A.; Sipilä, S. K.; Sips, A. C. C.; Sirén, P.; Sirinelli, A.; Sjöstrand, H.; Skiba, M.; Skilton, R.; Slabkowska, K.; Slade, B.; Smith, N.; Smith, P. G.; Smith, R.; Smith, T. J.; Smithies, M.; Snoj, L.; Soare, S.; Solano, E. R.; Somers, A.; Sommariva, C.; Sonato, P.; Sopplesa, A.; Sousa, J.; Sozzi, C.; Spagnolo, S.; Spelzini, T.; Spineanu, F.; Stables, G.; Stamatelatos, I.; Stamp, M. F.; Staniec, P.; Stankūnas, G.; Stan-Sion, C.; Stead, M. J.; Stefanikova, E.; Stepanov, I.; Stephen, A. V.; Stephen, M.; Stevens, A.; Stevens, B. D.; Strachan, J.; Strand, P.; Strauss, H. R.; Ström, P.; Stubbs, G.; Studholme, W.; Subba, F.; Summers, H. P.; Svensson, J.; Świderski, Ł.; Szabolics, T.; Szawlowski, M.; Szepesi, G.; Suzuki, T. T.; Tál, B.; Tala, T.; Talbot, A. R.; Talebzadeh, S.; Taliercio, C.; Tamain, P.; Tame, C.; Tang, W.; Tardocchi, M.; Taroni, L.; Taylor, D.; Taylor, K. A.; Tegnered, D.; Telesca, G.; Teplova, N.; Terranova, D.; Testa, D.; Tholerus, E.; Thomas, J.; Thomas, J. D.; Thomas, P.; Thompson, A.; Thompson, C.-A.; Thompson, V. K.; Thorne, L.; Thornton, A.; Thrysøe, A. S.; Tigwell, P. A.; Tipton, N.; Tiseanu, I.; Tojo, H.; Tokitani, M.; Tolias, P.; Tomeš, M.; Tonner, P.; Towndrow, M.; Trimble, P.; Tripsky, M.; Tsalas, M.; Tsavalas, P.; Tskhakaya jun, D.; Turner, I.; Turner, M. M.; Turnyanskiy, M.; Tvalashvili, G.; Tyrrell, S. G. J.; Uccello, A.; Ul-Abidin, Z.; Uljanovs, J.; Ulyatt, D.; Urano, H.; Uytdenhouwen, I.; Vadgama, A. P.; Valcarcel, D.; Valentinuzzi, M.; Valisa, M.; Vallejos Olivares, P.; Valovic, M.; Van De Mortel, M.; Van Eester, D.; Van Renterghem, W.; van Rooij, G. J.; Varje, J.; Varoutis, S.; Vartanian, S.; Vasava, K.; Vasilopoulou, T.; Vega, J.; Verdoolaege, G.; Verhoeven, R.; Verona, C.; Verona Rinati, G.; Veshchev, E.; Vianello, N.; Vicente, J.; Viezzer, E.; Villari, S.; Villone, F.; Vincenzi, P.; Vinyar, I.; Viola, B.; Vitins, A.; Vizvary, Z.; Vlad, M.; Voitsekhovitch, I.; Vondráček, P.; Vora, N.; Vu, T.; Pires de Sa, W. W.; Wakeling, B.; Waldon, C. W. F.; Walkden, N.; Walker, M.; Walker, R.; Walsh, M.; Wang, E.; Wang, N.; Warder, S.; Warren, R. J.; Waterhouse, J.; Watkins, N. W.; Watts, C.; Wauters, T.; Weckmann, A.; Weiland, J.; Weisen, H.; Weiszflog, M.; Wellstood, C.; West, A. T.; Wheatley, M. R.; Whetham, S.; Whitehead, A. M.; Whitehead, B. D.; Widdowson, A. M.; Wiesen, S.; Wilkinson, J.; Williams, J.; Williams, M.; Wilson, A. R.; Wilson, D. J.; Wilson, H. R.; Wilson, J.; Wischmeier, M.; Withenshaw, G.; Withycombe, A.; Witts, D. M.; Wood, D.; Wood, R.; Woodley, C.; Wray, S.; Wright, J.; Wright, J. C.; Wu, J.; Wukitch, S.; Wynn, A.; Xu, T.; Yadikin, D.; Yanling, W.; Yao, L.; Yavorskij, V.; Yoo, M. G.; Young, C.; Young, D.; Young, I. D.; Young, R.; Zacks, J.; Zagorski, R.; Zaitsev, F. S.; Zanino, R.; Zarins, A.; Zastrow, K. D.; Zerbini, M.; Zhang, W.; Zhou, Y.; Zilli, E.; Zoita, V.; Zoletnik, S.; Zychor, I.; JET Contributors

2017-10-01

The 2014-2016 JET results are reviewed in the light of their significance for optimising the ITER research plan for the active and non-active operation. More than 60 h of plasma operation with ITER first wall materials successfully took place since its installation in 2011. New multi-machine scaling of the type I-ELM divertor energy flux density to ITER is supported by first principle modelling. ITER relevant disruption experiments and first principle modelling are reported with a set of three disruption mitigation valves mimicking the ITER setup. Insights of the L-H power threshold in Deuterium and Hydrogen are given, stressing the importance of the magnetic configurations and the recent measurements of fine-scale structures in the edge radial electric. Dimensionless scans of the core and pedestal confinement provide new information to elucidate the importance of the first wall material on the fusion performance. H-mode plasmas at ITER triangularity (H  =  1 at β N ~ 1.8 and n/n GW ~ 0.6) have been sustained at 2 MA during 5 s. The ITER neutronics codes have been validated on high performance experiments. Prospects for the coming D-T campaign and 14 MeV neutron calibration strategy are reviewed.

A first-principle calculation of the XANES spectrum of Cu2+ in water

NASA Astrophysics Data System (ADS)

La Penna, G.; Minicozzi, V.; Morante, S.; Rossi, G. C.; Stellato, F.

2015-09-01

The progress in high performance computing we are witnessing today offers the possibility of accurate electron density calculations of systems in realistic physico-chemical conditions. In this paper, we present a strategy aimed at performing a first-principle computation of the low energy part of the X-ray Absorption Spectroscopy (XAS) spectrum based on the density functional theory calculation of the electronic potential. To test its effectiveness, we apply the method to the computation of the X-ray absorption near edge structure part of the XAS spectrum in the paradigmatic, but simple case of Cu2+ in water. In order to keep into account the effect of the metal site structure fluctuations in determining the experimental signal, the theoretical spectrum is evaluated as the average over the computed spectra of a statistically significant number of simulated metal site configurations. The comparison of experimental data with theoretical calculations suggests that Cu2+ lives preferentially in a square-pyramidal geometry. The remarkable success of this approach in the interpretation of XAS data makes us optimistic about the possibility of extending the computational strategy we have outlined to the more interesting case of molecules of biological relevance bound to transition metal ions.

A Novel Gas Sensor Transducer Based on Phthalocyanine Heterojunction Devices

PubMed Central

Muzikante, Inta; Parra, Vicente; Dobulans, Rorijs; Fonavs, Egils; Latvels, Janis; Bouvet, Marcel

2007-01-01

Experimental data concerning the changes in the current-voltage (I-V) performances of a molecular material-based heterojunction consisting of hexadecafluorinated nickel phthalocyanine (Ni(F16Pc)) and nickel phthalocyanine (NiPc), (Au|Ni(F16Pc)|NiPc|Al) are introduced as an unprecedented principle of transduction for gas sensing performances. The respective n- and p-type doped-insulator behaviors of the respective materials are supported, owing to the observed changes in surface potential (using the Kelvin probe method) after submission to electron donor (ammonia) and electron acceptor gases (ozone). On the other hand, the bilayer device exhibits strong variations in the built-in potential of the junction and in its rectification ratio. Moreover, large increases occur in forward and reverse currents in presence of ammonia vapors. These make possible a multimodal principle of detection controlled by a combined effect between the heterojunction and the NiPc|Al contact. Indeed, this metal/organic junction plays a critical role regarding the steady asymmetry of the I-V profiles during the device's doping even using high ammonia concentrations. This approach offers a more sophisticated alternative to the classically studied, but at times rather operation-limited, resistive gas sensors. PMID:28903274

Laser vision seam tracking system based on image processing and continuous convolution operator tracker

NASA Astrophysics Data System (ADS)

Zou, Yanbiao; Chen, Tao

2018-06-01

To address the problem of low welding precision caused by the poor real-time tracking performance of common welding robots, a novel seam tracking system with excellent real-time tracking performance and high accuracy is designed based on the morphological image processing method and continuous convolution operator tracker (CCOT) object tracking algorithm. The system consists of a six-axis welding robot, a line laser sensor, and an industrial computer. This work also studies the measurement principle involved in the designed system. Through the CCOT algorithm, the weld feature points are determined in real time from the noise image during the welding process, and the 3D coordinate values of these points are obtained according to the measurement principle to control the movement of the robot and the torch in real time. Experimental results show that the sensor has a frequency of 50 Hz. The welding torch runs smoothly with a strong arc light and splash interference. Tracking error can reach ±0.2 mm, and the minimal distance between the laser stripe and the welding molten pool can reach 15 mm, which can significantly fulfill actual welding requirements.

Self-optimizing, highly surface-active layered metal dichalcogenide catalysts for hydrogen evolution

NASA Astrophysics Data System (ADS)

Liu, Yuanyue; Wu, Jingjie; Hackenberg, Ken P.; Zhang, Jing; Wang, Y. Morris; Yang, Yingchao; Keyshar, Kunttal; Gu, Jing; Ogitsu, Tadashi; Vajtai, Robert; Lou, Jun; Ajayan, Pulickel M.; Wood, Brandon C.; Yakobson, Boris I.

2017-09-01

Low-cost, layered transition-metal dichalcogenides (MX2) based on molybdenum and tungsten have attracted substantial interest as alternative catalysts for the hydrogen evolution reaction (HER). These materials have high intrinsic per-site HER activity; however, a significant challenge is the limited density of active sites, which are concentrated at the layer edges. Here we unravel electronic factors underlying catalytic activity on MX2 surfaces, and leverage the understanding to report group-5 MX2 (H-TaS2 and H-NbS2) electrocatalysts whose performance instead mainly derives from highly active basal-plane sites, as suggested by our first-principles calculations and performance comparisons with edge-active counterparts. Beyond high catalytic activity, they are found to exhibit an unusual ability to optimize their morphology for enhanced charge transfer and accessibility of active sites as the HER proceeds, offering a practical advantage for scalable processing. The catalysts reach 10 mA cm-2 current density at an overpotential of ˜50-60 mV with a loading of 10-55 μg cm-2, surpassing other reported MX2 candidates without any performance-enhancing additives.

Tunnel Field-Effect Transistors in 2-D Transition Metal Dichalcogenide Materials

NASA Astrophysics Data System (ADS)

Ilatikhameneh, Hesameddin; Tan, Yaohua; Novakovic, Bozidar; Klimeck, Gerhard; Rahman, Rajib; Appenzeller, Joerg

2015-12-01

In this work, the performance of Tunnel Field-Effect Transistors (TFETs) based on two-dimensional Transition Metal Dichalcogenide (TMD) materials is investigated by atomistic quantum transport simulations. One of the major challenges of TFETs is their low ON-currents. 2D material based TFETs can have tight gate control and high electric fields at the tunnel junction, and can in principle generate high ON-currents along with a sub-threshold swing smaller than 60 mV/dec. Our simulations reveal that high performance TMD TFETs, not only require good gate control, but also rely on the choice of the right channel material with optimum band gap, effective mass and source/drain doping level. Unlike previous works, a full band atomistic tight binding method is used self-consistently with 3D Poisson equation to simulate ballistic quantum transport in these devices. The effect of the choice of TMD material on the performance of the device and its transfer characteristics are discussed. Moreover, the criteria for high ON-currents are explained with a simple analytic model, showing the related fundamental factors. Finally, the subthreshold swing and energy-delay of these TFETs are compared with conventional CMOS devices.

Integrating pharmacology topics in high school biology and chemistry classes improves performance

NASA Astrophysics Data System (ADS)

Schwartz-Bloom, Rochelle D.; Halpin, Myra J.

2003-11-01

Although numerous programs have been developed for Grade Kindergarten through 12 science education, evaluation has been difficult owing to the inherent problems conducting controlled experiments in the typical classroom. Using a rigorous experimental design, we developed and tested a novel program containing a series of pharmacology modules (e.g., drug abuse) to help high school students learn basic principles in biology and chemistry. High school biology and chemistry teachers were recruited for the study and they attended a 1-week workshop to learn how to integrate pharmacology into their teaching. Working with university pharmacology faculty, they also developed classroom activities. The following year, teachers field-tested the pharmacology modules in their classrooms. Students in classrooms using the pharmacology topics scored significantly higher on a multiple choice test of basic biology and chemistry concepts compared with controls. Very large effect sizes (up to 1.27 standard deviations) were obtained when teachers used as many as four modules. In addition, biology students increased performance on chemistry questions and chemistry students increased performance on biology questions. Substantial gains in achievement may be made when high school students are taught science using topics that are interesting and relevant to their own lives.

LL13-MatModelRadDetect-PD2Jf Final Report: Materials Modeling for High-Performance Radiation Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lordi, Vincenzo

The aims of this project are to enable rational materials design for select high-payoff challenges in radiation detection materials by using state-of-the-art predictive atomistic modeling techniques. Three specific high-impact challenges are addressed: (i) design and optimization of electrical contact stacks for TlBr detectors to stabilize temporal response at room-temperature; (ii) identification of chemical design principles of host glass materials for large-volume, low-cost, highperformance glass scintillators; and (iii) determination of the electrical impacts of dislocation networks in Cd 1-xZn xTe (CZT) that limit its performance and usable single-crystal volume. The specific goals are to establish design and process strategies to achievemore » improved materials for high performance detectors. Each of the major tasks is discussed below in three sections, which include the goals for the task and a summary of the major results, followed by a listing of publications that contain the full details, including details of the methodologies used. The appendix lists 12 conference presentations given for this project, including 1 invited talk and 1 invited poster.« less

The effect of high pressure torsion on structural refinement and mechanical properties of an austenitic stainless steel.

PubMed

Krawczynska, Agnieszka Teresa; Lewandowska, Malgorzata; Pippan, Reinhard; Kurzydlowski, Krzysztof Jan

2013-05-01

In the present study, the high pressure torsion (HPT) was used to refine the grain structure down to the nanometer scale in an austenitic stainless steel. The principles of HPT lay on torsional deformation under simultaneous high pressure of the specimen, which results in substantial reduction in the grain size. Disks of the 316LVM austenitic stainless steel of 10 mm in diameter were subjected to equivalent strains epsilon of 32 at RT and 450 degrees C under the pressure of 4 GPa. Furthermore, two-stage HPT processes, i.e., deformation at room temperature followed by deformation at 450 degrees C, were performed. The resulting microstructures were investigated in TEM observations. The mechanical properties were measured in terms of the microhardness and in tensile tests. HPT performed at two-stage conditions (firstly at RT next at 450 degrees C) gives similar values of microhardness to the ones obtained after deforming only at 450 degrees C but performed to higher values of the overall equivalent strain epsilon. The effect of high pressure torsion on structural refinement and mechanical properties of an austenitic stainless steel was evaluated.

Extreme ultraviolet interferometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldberg, Kenneth A.

EUV lithography is a promising and viable candidate for circuit fabrication with 0.1-micron critical dimension and smaller. In order to achieve diffraction-limited performance, all-reflective multilayer-coated lithographic imaging systems operating near 13-nm wavelength and 0.1 NA have system wavefront tolerances of 0.27 nm, or 0.02 waves RMS. Owing to the highly-sensitive resonant reflective properties of multilayer mirrors and extraordinarily tight tolerances set forth for their fabrication, EUV optical systems require at-wavelength EUV interferometry for final alignment and qualification. This dissertation discusses the development and successful implementation of high-accuracy EUV interferometric techniques. Proof-of-principle experiments with a prototype EUV point-diffraction interferometer for themore » measurement of Fresnel zoneplate lenses first demonstrated sub-wavelength EUV interferometric capability. These experiments spurred the development of the superior phase-shifting point-diffraction interferometer (PS/PDI), which has been implemented for the testing of an all-reflective lithographic-quality EUV optical system. Both systems rely on pinhole diffraction to produce spherical reference wavefronts in a common-path geometry. Extensive experiments demonstrate EUV wavefront-measuring precision beyond 0.02 waves RMS. EUV imaging experiments provide verification of the high-accuracy of the point-diffraction principle, and demonstrate the utility of the measurements in successfully predicting imaging performance. Complementary to the experimental research, several areas of theoretical investigation related to the novel PS/PDI system are presented. First-principles electromagnetic field simulations of pinhole diffraction are conducted to ascertain the upper limits of measurement accuracy and to guide selection of the pinhole diameter. Investigations of the relative merits of different PS/PDI configurations accompany a general study of the most significant sources of systematic measurement errors. To overcome a variety of experimental difficulties, several new methods in interferogram analysis and phase-retrieval were developed: the Fourier-Transform Method of Phase-Shift Determination, which uses Fourier-domain analysis to improve the accuracy of phase-shifting interferometry; the Fourier-Transform Guided Unwrap Method, which was developed to overcome difficulties associated with a high density of mid-spatial-frequency blemishes and which uses a low-spatial-frequency approximation to the measured wavefront to guide the phase unwrapping in the presence of noise; and, finally, an expedient method of Gram-Schmidt orthogonalization which facilitates polynomial basis transformations in wave-front surface fitting procedures.« less

Anthelmintic activity of a standardized extract from the rhizomes of Acorus calamus Linn. (Acoraceae) against experimentally induced cestodiasis in rats

PubMed Central

Nath, Purobi; Yadav, Arun K

2016-01-01

Background: The rhizomes of a herb Acorus calamus Linn. (Acoraceae) have been widely used as a traditional medicine to cure intestinal-helminthic infections in India and South Africa. Aim: This study was undertaken to investigate the in vivo anthelmintic activity of a standardized methanolic extract obtained from the rhizomes A. calamus in a rodent model. Materials and Methods: A methanolic extract obtained from rhizomes of A. calamus was characterized for active principle using nuclear magnetic resonance 1H NMR, 13C NMR, mass and infrared spectroscopy. The amount of active principle in rhizome isolated active fraction of plant was assayed using high-performance liquid chromatography (HPLC). Later, the standardized rhizome extract of plant and its active principle were tested for in vivo anthelmintic efficacy against experimentally induced Hymenolepis diminuta, a zoonotic cestode, infections in rats. Results: The study revealed that b-asarone is the active principle of plant. The HPLC analysis of local variety of A. calamus revealed that active fraction contains 83.54% (w/w) of b-asarone. The in vivo study revealed that treatment of H. diminuta infected rats by a single 800 mg/kg dose of rhizome extract for 5 days results into 62.30% reduction in eggs per gram of feces counts and 83.25% reduction in worm counts of animals. These findings compared well with the efficacy of a reference drug, praziquantel. The active principle b-asarone showed slightly better anthelmintic effects than crude extract. In acute toxicity assay, a single oral 2000 mg/kg dose of extract did not reveal any signs of toxicity or mortality in mice, and the LD50 of the extract was noted to be >2000 mg/kg. Conclusion: Taken together, the results of this study indicate that rhizomes of A. calamus bear significant dose-dependent effects against intestinal helminths. Further, the Indian variety of A. calamus contains high b-asarone content. Therefore, there exists a great potential to develop some suitable anthelmintic herbal products from this plant. PMID:27757269

Enhancing light-harvesting power with coherent vibrational interactions: A quantum heat engine picture

NASA Astrophysics Data System (ADS)

Killoran, N.; Huelga, S. F.; Plenio, M. B.

2015-10-01

Recent evidence suggests that quantum effects may have functional importance in biological light-harvesting systems. Along with delocalized electronic excitations, it is now suspected that quantum coherent interactions with certain near-resonant vibrations may contribute to light-harvesting performance. However, the actual quantum advantage offered by such coherent vibrational interactions has not yet been established. We investigate a quantum design principle, whereby coherent exchange of single energy quanta between electronic and vibrational degrees of freedom can enhance a light-harvesting system's power above what is possible by thermal mechanisms alone. We present a prototype quantum heat engine which cleanly illustrates this quantum design principle and quantifies its quantum advantage using thermodynamic measures of performance. We also demonstrate the principle's relevance in parameter regimes connected to natural light-harvesting structures.

High-Performance and Traditional Multicrystalline Silicon: Comparing Gettering Responses and Lifetime-Limiting Defects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castellanos, Sergio; Ekstrom, Kai E.; Autruffe, Antoine

2016-05-01

In recent years, high-performance multicrystalline silicon (HPMC-Si) has emerged as an attractive alternative to traditional ingot-based multicrystalline silicon (mc-Si), with a similar cost structure but improved cell performance. Herein, we evaluate the gettering response of traditional mc-Si and HPMC-Si. Microanalytical techniques demonstrate that HPMC-Si and mc-Si share similar lifetime-limiting defect types but have different relative concentrations and distributions. HPMC-Si shows a substantial lifetime improvement after P-gettering compared with mc-Si, chiefly because of lower area fraction of dislocation-rich clusters. In both materials, the dislocation clusters and grain boundaries were associated with relatively higher interstitial iron point-defect concentrations after diffusion, which ismore » suggestive of dissolving metal-impurity precipitates. The relatively fewer dislocation clusters in HPMC-Si are shown to exhibit similar characteristics to those found in mc-Si. Given similar governing principles, a proxy to determine relative recombination activity of dislocation clusters developed for mc-Si is successfully transferred to HPMC-Si.« less

Individual differences in children's understanding of inversion and arithmetical skill.

PubMed

Gilmore, Camilla K; Bryant, Peter

2006-06-01

Background and aims. In order to develop arithmetic expertise, children must understand arithmetic principles, such as the inverse relationship between addition and subtraction, in addition to learning calculation skills. We report two experiments that investigate children's understanding of the principle of inversion and the relationship between their conceptual understanding and arithmetical skills. A group of 127 children from primary schools took part in the study. The children were from 2 age groups (6-7 and 8-9 years). Children's accuracy on inverse and control problems in a variety of presentation formats and in canonical and non-canonical forms was measured. Tests of general arithmetic ability were also administered. Children consistently performed better on inverse than control problems, which indicates that they could make use of the inverse principle. Presentation format affected performance: picture presentation allowed children to apply their conceptual understanding flexibly regardless of the problem type, while word problems restricted their ability to use their conceptual knowledge. Cluster analyses revealed three subgroups with different profiles of conceptual understanding and arithmetical skill. Children in the 'high ability' and 'low ability' groups showed conceptual understanding that was in-line with their arithmetical skill, whilst a 3rd group of children had more advanced conceptual understanding than arithmetical skill. The three subgroups may represent different points along a single developmental path or distinct developmental paths. The discovery of the existence of the three groups has important consequences for education. It demonstrates the importance of considering the pattern of individual children's conceptual understanding and problem-solving skills.

Evolutionary mechanics: new engineering principles for the emergence of flexibility in a dynamic and uncertain world.

PubMed

Whitacre, James M; Rohlfshagen, Philipp; Bender, Axel; Yao, Xin

2012-09-01

Engineered systems are designed to deftly operate under predetermined conditions yet are notoriously fragile when unexpected perturbations arise. In contrast, biological systems operate in a highly flexible manner; learn quickly adequate responses to novel conditions, and evolve new routines and traits to remain competitive under persistent environmental change. A recent theory on the origins of biological flexibility has proposed that degeneracy-the existence of multi-functional components with partially overlapping functions-is a primary determinant of the robustness and adaptability found in evolved systems. While degeneracy's contribution to biological flexibility is well documented, there has been little investigation of degeneracy design principles for achieving flexibility in systems engineering. Actually, the conditions that can lead to degeneracy are routinely eliminated in engineering design. With the planning of transportation vehicle fleets taken as a case study, this article reports evidence that degeneracy improves the robustness and adaptability of a simulated fleet towards unpredicted changes in task requirements without incurring costs to fleet efficiency. We find that degeneracy supports faster rates of design adaptation and ultimately leads to better fleet designs. In investigating the limitations of degeneracy as a design principle, we consider decision-making difficulties that arise from degeneracy's influence on fleet complexity. While global decision-making becomes more challenging, we also find degeneracy accommodates rapid distributed decision-making leading to (near-optimal) robust system performance. Given the range of conditions where favorable short-term and long-term performance outcomes are observed, we propose that degeneracy may fundamentally alter the propensity for adaptation and is useful within different engineering and planning contexts.

Development of high performance refractory fibers with enhanced insulating properties and longer service lifetimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, P.C.; DePoorter, G.L.; Munoz, D.R.

1991-02-01

We have initiated a three phase investigation of the development of high performance refractory fibers with enhanced insulating properties and longer usable lifetimes. This report presents the results of the first phase of the study, performed from Aug. 1989 through Feb. 1991, which shows that significant energy saving are possible through the use of high temperature insulating fibers that better retain their efficient insulating properties during the service lifetime of the fibers. The remaining phases of this program include the pilot scale development and then full scale production feasibility development and evaluation of enhanced high temperature refractory insulting fibers. Thismore » first proof of principle phase of the program presents a summary of the current use patterns of refractory fibers, a laboratory evaluation of the high temperature performance characteristics of selected typical refractory fibers and an analysis of the potential energy savings through the use of enhanced refractory fibers. The current use patterns of refractory fibers span a wide range of industries and high temperature furnaces within those industries. The majority of high temperature fiber applications are in furnaces operating between 2000 and 26000{degrees}F. The fibers used in furnaces operating within this range provide attractive thermal resistance and low thermal storage at reasonable cost. A series of heat treatment studies performed for this phase of the program has shown that the refractory fibers, as initially manufactured, have attractive thermal conductivities for high temperature applications but the fibers go through rapid devitrification and subsequent crystal growth upon high temperature exposure. Development of improved fibers, maintaining the favorable characteristics of the existing as-manufactured fibers, could save between 1 and 4% of the energy consumed in high temperature furnaces using refractory fibers.« less

Using High-Dimensional Image Models to Perform Highly Undetectable Steganography

NASA Astrophysics Data System (ADS)

Pevný, Tomáš; Filler, Tomáš; Bas, Patrick

This paper presents a complete methodology for designing practical and highly-undetectable stegosystems for real digital media. The main design principle is to minimize a suitably-defined distortion by means of efficient coding algorithm. The distortion is defined as a weighted difference of extended state-of-the-art feature vectors already used in steganalysis. This allows us to "preserve" the model used by steganalyst and thus be undetectable even for large payloads. This framework can be efficiently implemented even when the dimensionality of the feature set used by the embedder is larger than 107. The high dimensional model is necessary to avoid known security weaknesses. Although high-dimensional models might be problem in steganalysis, we explain, why they are acceptable in steganography. As an example, we introduce HUGO, a new embedding algorithm for spatial-domain digital images and we contrast its performance with LSB matching. On the BOWS2 image database and in contrast with LSB matching, HUGO allows the embedder to hide 7× longer message with the same level of security level.

Fundamentals of Diesel Engines.

ERIC Educational Resources Information Center

Marine Corps Inst., Washington, DC.

This student guide, one of a series of correspondence training courses designed to improve the job performance of members of the Marine Corps, deals with the fundamentals of diesel engine mechanics. Addressed in the three individual units of the course are the following topics: basic principles of diesel mechanics; principles, mechanics, and…

Do Graphs Promote Learning in Principles of Economics?

ERIC Educational Resources Information Center

Cohn, Elchanan; Cohn, Sharon; Balch, Donald C.; Bradley, James, Jr.

2001-01-01

Tests the effects on student performance when using graphs as part of a University of South Carolina (Columbia) principles of economics lecture. Finds in 1995 that students in the lecture with graphs had significantly lower gain scores than those in the no-graphs lecture. Finds no significant difference in 1997. (RLH)

Experimental evaluation of a flexible I/O architecture for accelerating workflow engines in ultrascale environments

DOE PAGES

Duro, Francisco Rodrigo; Blas, Javier Garcia; Isaila, Florin; ...

2016-10-06

The increasing volume of scientific data and the limited scalability and performance of storage systems are currently presenting a significant limitation for the productivity of the scientific workflows running on both high-performance computing (HPC) and cloud platforms. Clearly needed is better integration of storage systems and workflow engines to address this problem. This paper presents and evaluates a novel solution that leverages codesign principles for integrating Hercules—an in-memory data store—with a workflow management system. We consider four main aspects: workflow representation, task scheduling, task placement, and task termination. As a result, the experimental evaluation on both cloud and HPC systemsmore » demonstrates significant performance and scalability improvements over existing state-of-the-art approaches.« less

[Risk management in anesthesia and critical care medicine].

PubMed

Eisold, C; Heller, A R

2017-03-01

Throughout its history, anesthesia and critical care medicine has experienced vast improvements to increase patient safety. Consequently, anesthesia has never been performed on such a high level as it is being performed today. As a result, we do not always fully perceive the risks involved in our daily activity. A survey performed in Swiss hospitals identified a total of 169 hot spots which endanger patient safety. It turned out that there is a complex variety of possible errors that can only be tackled through consistent implementation of a safety culture. The key elements to reduce complications are continuing staff education, algorithms and standard operating procedures (SOP), working according to the principles of crisis resource management (CRM) and last but not least the continuous work-up of mistakes identified by critical incident reporting systems.

Wuhan Ionospheric Oblique Backscattering Sounding System and Its Applications—A Review

PubMed Central

Shi, Shuzhu; Yang, Guobin; Jiang, Chunhua; Zhang, Yuannong; Zhao, Zhengyu

2017-01-01

For decades, high-frequency (HF) radar has played an important role in sensing the Earth’s environment. Advances in radar technology are providing opportunities to significantly improve the performance of HF radar, and to introduce more applications. This paper presents a low-power, small-size, and multifunctional HF radar developed by the Ionospheric Laboratory of Wuhan University, referred to as the Wuhan Ionospheric Oblique Backscattering Sounding System (WIOBSS). Progress in the development of this radar is described in detail, including the basic principles of operation, the system configuration, the sounding waveforms, and the signal and data processing methods. Furthermore, its various remote sensing applications are briefly reviewed to show the good performance of this radar. Finally, some suggested solutions are given for further improvement of its performance. PMID:28629157

Configural displays can improve nutrition-related. decisions: an application of the proximity compatibility principle.

PubMed

Marino, Christopher J; Mahan, Robert R

2005-01-01

The nutrition label format currently used by consumers to make dietary-related decisions presents significant information-processing demands for integration-based decisions; however, those demands were not considered as primary factors when the format was adopted. Labels designed in accordance with known principles of cognitive psychology might enhance the kind of decision making that food labeling was intended to facilitate. Three experiments were designed on the basis of the proximity compatibility principle (PCP) to investigate the relationship between nutrition label format and decision making; the experiments involved two types of integration decisions and one type of filtering decision. Based on the PCP, decision performance was measured to test the overall hypothesis that matched task-display tandems would result in better decision performance than would mismatched tandems. In each experiment, a statistically significant increase in mean decision performance was found when the display design was cognitively matched to the demands of the task. Combined, the results from all three experiments support the general hypothesis that task-display matching is a design principle that may enhance the utility of nutrition labeling in nutrition-related decision making. Actual or potential applications of this research include developing robust display solutions that aid in less effortful assimilation of nutrition-related information for consumers.

The precautionary principle in environmental science.

PubMed Central

Kriebel, D; Tickner, J; Epstein, P; Lemons, J; Levins, R; Loechler, E L; Quinn, M; Rudel, R; Schettler, T; Stoto, M

2001-01-01

Environmental scientists play a key role in society's responses to environmental problems, and many of the studies they perform are intended ultimately to affect policy. The precautionary principle, proposed as a new guideline in environmental decision making, has four central components: taking preventive action in the face of uncertainty; shifting the burden of proof to the proponents of an activity; exploring a wide range of alternatives to possibly harmful actions; and increasing public participation in decision making. In this paper we examine the implications of the precautionary principle for environmental scientists, whose work often involves studying highly complex, poorly understood systems, while at the same time facing conflicting pressures from those who seek to balance economic growth and environmental protection. In this complicated and contested terrain, it is useful to examine the methodologies of science and to consider ways that, without compromising integrity and objectivity, research can be more or less helpful to those who would act with precaution. We argue that a shift to more precautionary policies creates opportunities and challenges for scientists to think differently about the ways they conduct studies and communicate results. There is a complicated feedback relation between the discoveries of science and the setting of policy. While maintaining their objectivity and focus on understanding the world, environmental scientists should be aware of the policy uses of their work and of their social responsibility to do science that protects human health and the environment. The precautionary principle highlights this tight, challenging linkage between science and policy. PMID:11673114

Dose Control System in the Optima XE Single Wafer High Energy Ion Implanter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Satoh, Shu; Yoon, Jongyoon; David, Jonathan

2011-01-07

Photoresist outgassing can significantly compromise accurate dosimetry of high energy implants. High energy implant even at a modest beam current produces high beam powers which create significantly worse outgassing than low and medium energy implants and the outgassing continues throughout the implant due to the low dose in typical high energy implant recipes. In the previous generation of high energy implanters, dose correction by monitoring of process chamber pressure during photoresist outgassing has been used. However, as applications diversify and requirements change, the need arises for a more versatile photoresist correction system to match the versatility of a single wafermore » high energy ion implanter. We have successfully developed a new dosimetry system for the Optima XE single wafer high energy ion implanter which does not require any form of compensation due to the implant conditions. This paper describes the principles and performance of this new dose system.« less

Optimal Design of Dialyzers.

PubMed

Mineshima, Michio

2017-01-01

Several types of synthetic dialysis membranes, including polysulfone, polyethersulfone, and polyester polymer alloy membranes, have asymmetrical structures. Dialyzers with these membranes show higher water and solute transport performance because the actual membrane thickness, which is related to the water and solute transfer resistance, is quite small compared with that in membranes with a homogeneous structure. The performance of a dialyzer depends not only on membrane permeability to water and solutes, but also on flow conditions of the blood and dialysate, which are determined during dialyzer fabrication. Many types of high-flux dialyzers with high-performance membranes have a high internal filtration/backfiltration (IF/BF) flow rate. In the enhanced IF/BF dialyzer, membrane fouling occurs more readily than with the conventional dialyzer because of the high local transmembrane pressure needed to enhance the IF/BF flow rate. To select the optimal enhanced IF/BF dialyzer for individual patients, we need to balance the disadvantage of membrane fouling with the advantage of increased convective transport. Key Messages: The following principles should guide dialyzer development in the near term. (1) Dialyzers should show high performance for the removal of low-molecular-weight proteins related to certain complications under conditions of low albumin and amino acid loss. (2) Dialyzers with biocompatible membranes are required to prevent severe adverse reactions, even though the causal relationship between these reactions and some complications remains to be clarified. © 2017 S. Karger AG, Basel.

An Optoelectronic Equivalent Narrowband Filter for High Resolution Optical Spectrum Analysis

PubMed Central

Feng, Kunpeng; Cui, Jiwen; Dang, Hong; Wu, Weidong; Sun, Xun; Jiang, Xuelin; Tan, Jiubin

2017-01-01

To achieve a narrow bandwidth optical filter with a wide swept range for new generation optical spectrum analysis (OSA) of high performance optical sensors, an optoelectronic equivalent narrowband filter (OENF) was investigated and a swept optical filter with bandwidth of several MHz and sweep range of several tens of nanometers was built using electric filters and a sweep laser as local oscillator (LO). The principle of OENF is introduced and analysis of the OENF system is presented. Two electric filters are optimized to be RBW filters for high and medium spectral resolution applications. Both simulations and experiments are conducted to verify the OENF principle and the results show that the power uncertainty is less than 1.2% and the spectral resolution can reach 6 MHz. Then, a real-time wavelength calibration system consisting of a HCN gas cell and Fabry–Pérot etalon is proposed to guarantee a wavelength accuracy of ±0.4 pm in the C-band and to reduce the influence of phase noise and nonlinear velocity of the LO sweep. Finally, OSA experiments on actual spectra of various optical sensors are conducted using the OENF system. These experimental results indicate that OENF system has an excellent capacity for the analysis of fine spectrum structures. PMID:28208624

High sensitivity test of the Pauli Exclusion Principle for electrons with X-ray spectroscopy (VIP2)

NASA Astrophysics Data System (ADS)

Marton, Johann; VIP2 Collaboration

2015-10-01

The Pauli Exclusion Principle (PEP) is one of the most fundamental rules in physics and it has various important consequences ranging from atomic and subatomic systems to the stability of matter and stellar objects like neutron stars. Due to many observations This rule must be valid to an extremely high degree and consequently no violations were found so far. On the other hand a simple explanation of PEP is still missing. Many experimental investigations based on different assumptions were performed to search for a tiny PEP violation in various systems. The experiment VIP2 at the Gran Sasso underground laboratory (LNGS of INFN) is designed to test the PEP for electrons with high sensitivity by searching for forbidden X-ray transitions in copper atoms. This experiment aims to improve the PEP violation limit obtained with our preceding experiment VIP by orders of magnitude. The experimental method, comparison of the VIP result with different PEP searches and the present status of the VIP2 experiment will be presented. We acknowledge the support from the: HadronPhysics FP6 (506078), HadronPhysics2 FP7 (227431), HadronPhysics3 (283286) projects, EU COST Action 1006 (Fundamental Problems in Quantum Physics) and the Austrian Science Fund (FWF).

An Optoelectronic Equivalent Narrowband Filter for High Resolution Optical Spectrum Analysis.

PubMed

Feng, Kunpeng; Cui, Jiwen; Dang, Hong; Wu, Weidong; Sun, Xun; Jiang, Xuelin; Tan, Jiubin

2017-02-10

To achieve a narrow bandwidth optical filter with a wide swept range for new generation optical spectrum analysis (OSA) of high performance optical sensors, an optoelectronic equivalent narrowband filter (OENF) was investigated and a swept optical filter with bandwidth of several MHz and sweep range of several tens of nanometers was built using electric filters and a sweep laser as local oscillator (LO). The principle of OENF is introduced and analysis of the OENF system is presented. Two electric filters are optimized to be RBW filters for high and medium spectral resolution applications. Both simulations and experiments are conducted to verify the OENF principle and the results show that the power uncertainty is less than 1.2% and the spectral resolution can reach 6 MHz. Then, a real-time wavelength calibration system consisting of a HCN gas cell and Fabry-Pérot etalon is proposed to guarantee a wavelength accuracy of ±0.4 pm in the C-band and to reduce the influence of phase noise and nonlinear velocity of the LO sweep. Finally, OSA experiments on actual spectra of various optical sensors are conducted using the OENF system. These experimental results indicate that OENF system has an excellent capacity for the analysis of fine spectrum structures.

Going beyond a First Reader: A Machine Learning Methodology for Optimizing Cost and Performance in Breast Ultrasound Diagnosis.

PubMed

Venkatesh, Santosh S; Levenback, Benjamin J; Sultan, Laith R; Bouzghar, Ghizlane; Sehgal, Chandra M

2015-12-01

The goal of this study was to devise a machine learning methodology as a viable low-cost alternative to a second reader to help augment physicians' interpretations of breast ultrasound images in differentiating benign and malignant masses. Two independent feature sets consisting of visual features based on a radiologist's interpretation of images and computer-extracted features when used as first and second readers and combined by adaptive boosting (AdaBoost) and a pruning classifier resulted in a very high level of diagnostic performance (area under the receiver operating characteristic curve = 0.98) at a cost of pruning a fraction (20%) of the cases for further evaluation by independent methods. AdaBoost also improved the diagnostic performance of the individual human observers and increased the agreement between their analyses. Pairing AdaBoost with selective pruning is a principled methodology for achieving high diagnostic performance without the added cost of an additional reader for differentiating solid breast masses by ultrasound. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

A multilevel perspective on faultlines: Differentiating the effects between group- and organizational-level faultlines.

PubMed

Bezrukova, Katerina; Spell, Chester S; Caldwell, David; Burger, Jerry M

2016-01-01

Integrating the literature on faultlines, conflict, and pay, we drew on the basic principles of multilevel theory and differentiated between group- and organizational-level faultlines to introduce a novel multilevel perspective on faultlines. Using multisource, multilevel data on 30 Major League Baseball (MLB) teams, we found that group-level faultlines were negatively associated with group performance, and that internally focused conflict exacerbated but externally focused conflict mitigated this effect. Organizational-level faultlines were negatively related to organizational performance, and were most harmful in organizations with high levels of compensation. Implications for groups and teams in the sports/entertainment and other industries are discussed. (c) 2016 APA, all rights reserved).

Principles and performance of tapered fiber lasers: from uniform to flared geometry.

PubMed

Kerttula, Juho; Filippov, Valery; Chamorovskii, Yuri; Ustimchik, Vasily; Golant, Konstantin; Okhotnikov, Oleg G

2012-10-10

We have studied the recently demonstrated concept of fiber lasers based on active tapered double-clad fiber (T-DCF) in copropagating and counterpropagating configurations, both theoretically and experimentally, and compared the performance to fiber lasers based on conventional cylindrical fibers in end-pumped configurations. Specific properties of T-DCFs were considered theoretically using a rate-equation model developed for tapered fibers, and a detailed comparative study was carried out experimentally. Furthermore, we have studied mode coupling effects in long adiabatic tapers due to coiling and local bending. The results allow us to conclude that, with proper fiber design, the T-DCF technology offers a high-potential alternative for bright, cost-effective fiber devices.

Biomimetics: determining engineering opportunities from nature

NASA Astrophysics Data System (ADS)

Fish, Frank E.

2009-08-01

The biomimetic approach seeks to incorporate designs based on biological organisms into engineered technologies. Biomimetics can be used to engineer machines that emulate the performance of organisms, particularly in instances where the organism's performance exceeds current mechanical technology or provides new directions to solve existing problems. For biologists, an adaptationist program has allowed for the identification of novel features of organisms based on engineering principles; whereas for engineers, identification of such novel features is necessary to exploit them for biomimetic development. Adaptations (leading edge tubercles to passively modify flow and high efficiency oscillatory propulsive systems) from marine animals demonstrate potential utility in the development of biomimetic products. Nature retains a store of untouched knowledge, which would be beneficial in advancing technology.

Screening approach by ultra-high performance liquid chromatography-tandem mass spectrometry for the blood quantification of thirty-four toxic principles of plant origin. Application to forensic toxicology.

PubMed

Carlier, Jérémy; Guitton, Jérôme; Romeuf, Ludovic; Bévalot, Fabien; Boyer, Baptiste; Fanton, Laurent; Gaillard, Yvan

2015-01-15

Plant poisonings have left their mark on history and still cause many deaths, whether intentional or accidental. The means to show toxicological evidence of such poisonings should be implemented with great care. This article presents a technique for measuring thirty-nine toxic principles of plant origin in the blood, covering a large amount of toxins from local or exotic plants: α-lobeline, α-solanine, aconitine, ajmaline, atropine, brucine, cephalomannine, colchicine, convallatoxin, cymarine, cytisine, digitoxin, digoxin, emetine, gelsemine, ibogaine, jervine, kavain, lanatoside C, lupanine, mitragynine, neriifolin, oleandrin, ouabain, paclitaxel, physostigmine, pilocarpine, podophyllotoxin, proscillaridin A, reserpine, retrorsine, ricinine, scopolamine, senecionine, sparteine, strophanthidin, strychnine, veratridine and yohimbine. Analysis was carried out using an original ultra-high performance liquid chromatography separation coupled with tandem mass spectrometry detection. Extraction was a standard solid phase extraction performed on Oasis(®) HLB cartridge. Thirty-four of the thirty-nine compounds were put through a validation procedure. The assay was linear in the calibration curve range from 0.5 or 5 μg/L to 1000 μg/L according to the compounds. The method is sensitive (LOD from 0.1 to 1.6 μg/L). The within-day precision of the assay was less than 22.5% at the LLOQ, and the between-day precision was less than 21.5% for 10 μg/L for all the compounds included. The assay accuracy was in the range of 87.4 to 119.8% for the LLOQ. The extraction recovery and matrix effect ranged from 30 to 106% and from -30 to 14%, respectively. It has proven useful and effective in several difficult forensic cases. Copyright © 2014 Elsevier B.V. All rights reserved.

Implementation of a patient safety program at a tertiary health system: A longitudinal analysis of interventions and serious safety events.

PubMed

Cropper, Douglas P; Harb, Nidal H; Said, Patricia A; Lemke, Jon H; Shammas, Nicolas W

2018-04-01

We hypothesize that implementation of a safety program based on high reliability organization principles will reduce serious safety events (SSE). The safety program focused on 7 essential elements: (a) safety rounding, (b) safety oversight teams, (c) safety huddles, (d) safety coaches, (e) good catches/safety heroes, (f) safety education, and (g) red rule. An educational curriculum was implemented focusing on changing high-risk behaviors and implementing critical safety policies. All unusual occurrences were captured in the Midas system and investigated by risk specialists, the safety officer, and the chief medical officer. A multidepartmental committee evaluated these events, and a root cause analysis (RCA) was performed. Events were tabulated and serious safety event (SSE) recorded and plotted over time. Safety success stories (SSSs) were also evaluated over time. A steady drop in SSEs was seen over 9 years. Also a rise in SSSs was evident, reflecting on staff engagement in the program. The parallel change in SSEs, SSSs, and the implementation of various safety interventions highly suggest that the program was successful in achieving its goals. A safety program based on high-reliability organization principles and made a core value of the institution can have a significant positive impact on reducing SSEs. © 2018 American Society for Healthcare Risk Management of the American Hospital Association.

Space Weather, Geomagnetic Disturbances and Impact on the High-Voltage Transmission Systems

NASA Technical Reports Server (NTRS)

Pullkkinen, A.

2011-01-01

Geomagnetically induced currents (GIC) affecting the performance of high-voltage power transmission systems are one of the most significant hazards space weather poses on the operability of critical US infrastructure. The severity of the threat was emphasized, for example, in two recent reports: the National Research Council (NRC) report "Severe Space Weather Events--Understanding Societal and Economic Impacts: A Workshop Report" and the North American Electric Reliability Corporation (NERC) report "HighImpact, Low-Frequency Event Risk to the North American Bulk Power System." The NRC and NERC reports demonstrated the important national security dimension of space weather and GIC and called for comprehensive actions to forecast and mitigate the hazard. In this paper we will give a brief overview of space weather storms and accompanying geomagnetic storm events that lead to GIC. We will also review the fundamental principles of how GIC can impact the power transmission systems. Space weather has been a subject of great scientific advances that have changed the wonder of the past to a quantitative field of physics with true predictive power of today. NASA's Solar Shield system aimed at forecasting of GIC in the North American high-voltage power transmission system can be considered as one of the ultimate fruits of those advances. We will review the fundamental principles of the Solar Shield system and provide our view of the way forward in the science of GIC.

First principles study on electrochemical and chemical stability of solid electrolyte–electrode interfaces in all-solid-state Li-ion batteries

DOE PAGES

Zhu, Yizhou; He, Xingfeng; Mo, Yifei

2015-12-11

All-solid-state Li-ion batteries based on ceramic solid electrolyte materials are a promising next-generation energy storage technology with high energy density and enhanced cycle life. The poor interfacial conductance is one of the key limitations in enabling all-solid-state Li-ion batteries. However, the origin of this poor conductance has not been understood, and there is limited knowledge about the solid electrolyte–electrode interfaces in all-solid-state Li-ion batteries. In this paper, we performed first principles calculations to evaluate the thermodynamics of the interfaces between solid electrolyte and electrode materials and to identify the chemical and electrochemical stabilities of these interfaces. Our computation results revealmore » that many solid electrolyte–electrode interfaces have limited chemical and electrochemical stability, and that the formation of interphase layers is thermodynamically favorable at these interfaces. These formed interphase layers with different properties significantly affect the electrochemical performance of all-solid-state Li-ion batteries. The mechanisms of applying interfacial coating layers to stabilize the interface and to reduce interfacial resistance are illustrated by our computation. This study demonstrates a computational scheme to evaluate the chemical and electrochemical stability of heterogeneous solid interfaces. Finally, the enhanced understanding of the interfacial phenomena provides the strategies of interface engineering to improve performances of all-solid-state Li-ion batteries.« less

Fourier domain mode locking at 1050 nm for ultra-high-speed optical coherence tomography of the human retina at 236,000 axial scans per second.

PubMed

Huber, R; Adler, D C; Srinivasan, V J; Fujimoto, J G

2007-07-15

A Fourier domain mode-locked (FDML) laser at 1050 nm for ultra-high-speed optical coherence tomography (OCT) imaging of the human retina is demonstrated. Achievable performance, physical limitations, design rules, and scaling principles for FDML operation and component choice in this wavelength range are discussed. The fiber-based FDML laser operates at a sweep rate of 236 kHz over a 63 nm tuning range, with 7 mW average output power. Ultra-high-speed retinal imaging is demonstrated at 236,000 axial scans per second. This represents a speed improvement of approximately10x over typical high-speed OCT systems, paving the way for densely sampled volumetric data sets and new imaging protocols.

Principles of appendage design in robots and animals determining terradynamic performance on flowable ground.

PubMed

Qian, Feifei; Zhang, Tingnan; Korff, Wyatt; Umbanhowar, Paul B; Full, Robert J; Goldman, Daniel I

2015-10-08

Natural substrates like sand, soil, leaf litter and snow vary widely in penetration resistance. To search for principles of appendage design in robots and animals that permit high performance on such flowable ground, we developed a ground control technique by which the penetration resistance of a dry granular substrate could be widely and rapidly varied. The approach was embodied in a device consisting of an air fluidized bed trackway in which a gentle upward flow of air through the granular material resulted in a decreased penetration resistance. As the volumetric air flow, Q, increased to the fluidization transition, the penetration resistance decreased to zero. Using a bio-inspired hexapedal robot as a physical model, we systematically studied how locomotor performance (average forward speed, v(x)) varied with ground penetration resistance and robot leg frequency. Average robot speed decreased with increasing Q, and decreased more rapidly for increasing leg frequency, ω. A universal scaling model revealed that the leg penetration ratio (foot pressure relative to penetration force per unit area per depth and leg length) determined v(x) for all ground penetration resistances and robot leg frequencies. To extend our result to include continuous variation of locomotor foot pressure, we used a resistive force theory based terradynamic approach to perform numerical simulations. The terradynamic model successfully predicted locomotor performance for low resistance granular states. Despite variation in morphology and gait, the performance of running lizards, geckos and crabs on flowable ground was also influenced by the leg penetration ratio. In summary, appendage designs which reduce foot pressure can passively maintain minimal leg penetration ratio as the ground weakens, and consequently permits maintenance of effective locomotion over a range of terradynamically challenging surfaces.

Children's selective trust decisions: rational competence and limiting performance factors.

PubMed

Hermes, Jonas; Behne, Tanya; Bich, Anna Elisa; Thielert, Christa; Rakoczy, Hannes

2018-03-01

Recent research has amply documented that even preschoolers learn selectively from others, preferring, for example, reliable over unreliable and competent over incompetent models. It remains unclear, however, what the cognitive foundations of such selective learning are, in particular, whether it builds on rational inferences or on less sophisticated processes. The current study, therefore, was designed to test directly the possibility that children are in principle capable of selective learning based on rational inference, yet revert to simpler strategies such as global impression formation under certain circumstances. Preschoolers (N = 75) were shown pairs of models that either differed in their degree of competence within one domain (strong vs. weak or knowledgeable vs. ignorant) or were both highly competent, but in different domains (e.g., strong vs. knowledgeable model). In the test trials, children chose between the models for strength- or knowledge-related tasks. The results suggest that, in fact, children are capable of rational inference-based selective trust: when both models were highly competent, children preferred the model with the competence most predictive and relevant for a given task. However, when choosing between two models that differed in competence on one dimension, children reverted to halo-style wide generalizations and preferred the competent models for both relevant and irrelevant tasks. These findings suggest that the rational strategies for selective learning, that children master in principle, can get masked by various performance factors. © 2017 John Wiley & Sons Ltd.

High-Energy-Density-Physics Studies for Inertial Confinement Fusion Applications

NASA Astrophysics Data System (ADS)

Hu, S. X.

2017-10-01

Accurate knowledge of the static, transport, and optical properties of high-energy-density (HED) plasmas is essential for reliably designing and understanding inertial confinement fusion (ICF) implosions. In the warm-dense-matter regime routinely accessed by low-adiabat ICF implosions, many-body strong-coupling and quantum electron degeneracy effects play an important role in determining plasma properties. The past several years have witnessed intense efforts to assess the importance of the microphysics of ICF targets, both theoretically and experimentally. On the theory side, first-principles methods based on quantum mechanics have been applied to investigate the properties of warm, dense plasmas. Specifically, self-consistent investigations have recently been performed on the equation of state, thermal conductivity, and opacity of a variety of ICF ablators such as polystyrene (CH), beryllium, carbon, and silicon over a wide range of densities and temperatures. In this talk, we will focus on the most-recent progress on these ab initio HED physics studies, which generally result in favorable comparisons with experiments. Upon incorporation into hydrocodes for ICF simulations, these first-principles ablator-plasma properties have produced significant differences over traditional models in predicting 1-D target performance of ICF implosions on OMEGA and direct-drive-ignition designs for the National Ignition Facility. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944. *In collaboration with L. A. Collins, T. R. Boehly, G. W. Collins, J. D. Kress, and V. N. Goncharov.

Clinical management of renal cell carcinoma with venous tumor thrombus.

PubMed

Agochukwu, Nnenaya; Shuch, Brian

2014-06-01

Venous invasion is common in advanced renal cell carcinoma (RCC) due to the unique biology of this cancer. The presence of a tumor thrombus often makes clinical management challenging. In this review, we detail specific preoperative, perioperative, and surgical strategies involving the care of the complex kidney cancer patient with venous tumor involvement. We performed a comprehensive review of selected peer-reviewed publications regarding RCC tumor thrombus biology, medical and surgical management techniques, and immediate and long-term outcomes. The perioperative management may require special imaging techniques, preoperative testing, very recent imaging, and consultation with other surgical services. There are various approaches to these patients as the clinical presentation, stage of disease, primary tumor size, level of thrombus, degree of venous occlusion, presence of bland thrombus, and primary tumor laterality influence management. Select patients with metastatic disease can do well with cytoreductive nephrectomy and thrombectomy. Those with localized disease have a high risk of recurrence; however, some patients can exhibit durable survival with surgery alone. The evolving surgical and medical treatments are discussed. Even when these surgeries are performed in high volume centers, significant perioperative complications are common and greater complications are seen with higher thrombus extent. If surgery is attempted, it is important for urologic oncologists to follow strict attention to specific surgical principles. These general principles include complete vascular control, avoidance of thrombus embolization, close hemodynamic monitoring, and institutional resources for caval resection/replacement and venous bypass if necessary.

A novel gene network inference algorithm using predictive minimum description length approach.

PubMed

Chaitankar, Vijender; Ghosh, Preetam; Perkins, Edward J; Gong, Ping; Deng, Youping; Zhang, Chaoyang

2010-05-28

Reverse engineering of gene regulatory networks using information theory models has received much attention due to its simplicity, low computational cost, and capability of inferring large networks. One of the major problems with information theory models is to determine the threshold which defines the regulatory relationships between genes. The minimum description length (MDL) principle has been implemented to overcome this problem. The description length of the MDL principle is the sum of model length and data encoding length. A user-specified fine tuning parameter is used as control mechanism between model and data encoding, but it is difficult to find the optimal parameter. In this work, we proposed a new inference algorithm which incorporated mutual information (MI), conditional mutual information (CMI) and predictive minimum description length (PMDL) principle to infer gene regulatory networks from DNA microarray data. In this algorithm, the information theoretic quantities MI and CMI determine the regulatory relationships between genes and the PMDL principle method attempts to determine the best MI threshold without the need of a user-specified fine tuning parameter. The performance of the proposed algorithm was evaluated using both synthetic time series data sets and a biological time series data set for the yeast Saccharomyces cerevisiae. The benchmark quantities precision and recall were used as performance measures. The results show that the proposed algorithm produced less false edges and significantly improved the precision, as compared to the existing algorithm. For further analysis the performance of the algorithms was observed over different sizes of data. We have proposed a new algorithm that implements the PMDL principle for inferring gene regulatory networks from time series DNA microarray data that eliminates the need of a fine tuning parameter. The evaluation results obtained from both synthetic and actual biological data sets show that the PMDL principle is effective in determining the MI threshold and the developed algorithm improves precision of gene regulatory network inference. Based on the sensitivity analysis of all tested cases, an optimal CMI threshold value has been identified. Finally it was observed that the performance of the algorithms saturates at a certain threshold of data size.

Effective application of optical sensing technology for sustainable liquid level sensing and rainfall measurement

NASA Astrophysics Data System (ADS)

Afzal, Muhammad Hassan Bin

2015-05-01

Rainfall measurement is performed on regular basis to facilitate effectively the weather stations and local inhabitants. Different types of rain gauges are available with different measuring principle for rainfall measurement. In this research work, a novel optical rain sensor is designed, which precisely calculate the rainfall level according to rainfall intensity. This proposed optical rain sensor model introduced in this paper, which is basically designed for remote sensing of rainfall and it designated as R-ORMS (Remote Optical Rainfall Measurement sensor). This sensor is combination of some improved method of tipping bucket rain gauge and most of the optical hydreon rain sensor's principle. This optical sensor can detect the starting time and ending time of rain, rain intensity and rainfall level. An infrared beam from Light Emitting Diode (LED) through powerful convex lens can accurately determines the diameter of each rain drops by total internal reflection principle. Calculations of these accumulative results determine the rain intensity and rainfall level. Accurate rainfall level is determined by internal optical LED based sensor which is embedded in bucket wall. This internal sensor is also following the total internal reflection (TIR) principle and the Fresnel's law. This is an entirely novel design of optical sensing principle based rain sensor and also suitable for remote sensing rainfall level. The performance of this proposed sensor has been comprehensively compared with other sensors with similar attributes and it showed better and sustainable result. Future related works have been proposed at the end of this paper, to provide improved and enhanced performance of proposed novel rain sensor.

Using Cartoons to Transfer Knowledge Concerning the Principles of Work Disability Prevention Among Stakeholders.

PubMed

Labrecque, Marie-Elise; Coutu, Marie-France; Durand, Marie-José; Fassier, Jean-Baptiste; Loisel, Patrick

2016-06-01

Purpose This study assesses how well two cartoons transfer knowledge of principles of work disability prevention among stakeholders, according to their level of experience. We also document stakeholders' perceptions of the usefulness of the cartoons. Method We performed a descriptive study. Two groups of stakeholders were recruited: (1) experienced (working for more than 2 years in work disability), (2) non-experienced (in training). A self-administered questionnaire with open-ended questions documented stakeholders' understanding of each cartoon box and their perception of the possible usefulness of the cartoons. We transformed qualitative responses into quantitative responses for descriptive purposes. We performed independent t tests to compare the groups' level of understanding, and content analysis for the perception of usefulness. Results Overall, 149 stakeholders (50 experienced and 99 non-experienced) participated and identified 79.4 and 61.4 % of all principles presented in each of the two cartoons respectively. Experienced stakeholders identified more principles compared to non-experienced stakeholders (p = 0.007). Both cartoons were perceived to be useful for knowledge transfer. Conclusions Principles were generally well identified in the cartoons by all participants. Cartoons can be used as an effective tool among stakeholders to achieve a common understanding in order to coordinate their actions.

Sensitive Nonenzymatic Electrochemical Glucose Detection Based on Hollow Porous NiO

NASA Astrophysics Data System (ADS)

He, Gege; Tian, Liangliang; Cai, Yanhua; Wu, Shenping; Su, Yongyao; Yan, Hengqing; Pu, Wanrong; Zhang, Jinkun; Li, Lu

2018-01-01

Transition metal oxides (TMOs) have attracted extensive research attentions as promising electrocatalytic materials. Despite low cost and high stability, the electrocatalytic activity of TMOs still cannot satisfy the requirements of applications. Inspired by kinetics, the design of hollow porous structure is considered as a promising strategy to achieve superior electrocatalytic performance. In this work, cubic NiO hollow porous architecture (NiO HPA) was constructed through coordinating etching and precipitating (CEP) principle followed by post calcination. Being employed to detect glucose, NiO HPA electrode exhibits outstanding electrocatalytic activity in terms of high sensitivity (1323 μA mM-1 cm-2) and low detection limit (0.32 μM). The excellent electrocatalytic activity can be ascribed to large specific surface area (SSA), ordered diffusion channels, and accelerated electron transfer rate derived from the unique hollow porous features. The results demonstrate that the NiO HPA could have practical applications in the design of nonenzymatic glucose sensors. The construction of hollow porous architecture provides an effective nanoengineering strategy for high-performance electrocatalysts.

Correlation between defect transition levels and thermoelectric operational temperature of doped CrSi2

NASA Astrophysics Data System (ADS)

Singh, Abhishek; Pandey, Tribhuwan

2014-03-01

The performance of a thermoelectric material is quantified by figure of merit ZT. The challenge in achieving high ZT value requires simultaneously high thermopower, high electrical conductivity and low thermal conductivity at optimal carrier concentration. So far doping is the most versatile approach used for modifying thermoelectric properties. Previous studies have shown that doping can significantly improve the thermoelectric performance, however the tuning the operating temperature of a thermoelectric device is a main issue. Using first principles density functional theory, we report for CrSi2, a linear relationship between thermodynamic charge state transition levels of defects and temperature at which thermopower peaks. We show for doped CrSi2 that the peak of thermopower occurs at the temperature Tm, which corresponds to the position of defect transition level. Therefore, by modifying the defect transition level, a thermoelectric material with a given operational temperature can be designed. The authors thankfully acknowledge support from ADA under NpMASS.

Novel Rubidium Poly-Nitrogen Energetic Materials

NASA Astrophysics Data System (ADS)

Huff, Ashley; Steele, Brad; Oleynik, Ivan

High-nitrogen content compounds are being actively explored with the goal of discovering new high-energy density materials with performance surpassing the conventional energetic materials such as HMX or RDX. Although pure polynitrogen compounds such as cg-N are predicted to deliver 10-fold increase in detonation pressure and detonation velocity of 30 km/s, their synthesis and recovery at ambient conditions is problematic. Doping polynitrogens with other elements is a viable route to promote metastability while reducing synthesis pressure. In this work, rubidium poly-nitrides are being investigated as candidates for high energy density materials. Using first principles evolutionary structure search methods performed at varying stoichiometries and several pressures ranging from 0 to 100 GPa, several new polynitrogen compounds have been discovered. The phase diagrams containing thermodynamically stable and lowest metastable phases are calculated and the dynamical stability of the promising materials is investigated at various pressures. Raman spectra and XRD patterns are also calculated to provide experimentally relevant information useful for identification of these compounds during their synthesis.

First-Principles Materials Design of High-Performing Bulk Photovoltaics with the Li Nb O 3 Structure

DOE PAGES

Young, Steve M.; Zheng, Fan; Rappe, Andrew M.

2015-11-18

Here, the bulk photovoltaic effect is a long-known but poorly understood phenomenon. Recently, however, the multiferroic bismuth ferrite has been observed to produce strong photovoltaic response to visible light, suggesting that the effect has been underexploited as well. Here we present three polar oxides in the LiNbOmore » $$_3$$ structure that we predict to have band gaps in the 1-2 eV range and very high bulk photovoltaic response: PbNiO$$_3$$, Mg$$_{1/2}$$Zn$$_{1/2}$$PbO$$_3$$, and LiBiO$$_3$$. All three have band gaps determined by cations with $$d^{10}s^0$$ electronic configurations, leading to conduction bands composed of cation $s$-orbitals and O $p$-orbitals. This both dramatically lowers the band gap and increases the bulk photovoltaic response by as much as an order of magnitude over previous materials, demonstrating the potential for high-performing bulk photovoltaics.« less

Refined Zigzag Theory for Homogeneous, Laminated Composite, and Sandwich Plates: A Homogeneous Limit Methodology for Zigzag Function Selection

NASA Technical Reports Server (NTRS)

Tessler, Alexander; DiSciuva, Marco; Gherlone, marco

2010-01-01

The Refined Zigzag Theory (RZT) for homogeneous, laminated composite, and sandwich plates is presented from a multi-scale formalism starting with the inplane displacement field expressed as a superposition of coarse and fine contributions. The coarse kinematic field is that of first-order shear-deformation theory, whereas the fine kinematic field has a piecewise-linear zigzag distribution through the thickness. The condition of limiting homogeneity of transverse-shear properties is proposed and yields four distinct sets of zigzag functions. By examining elastostatic solutions for highly heterogeneous sandwich plates, the best-performing zigzag functions are identified. The RZT predictive capabilities to model homogeneous and highly heterogeneous sandwich plates are critically assessed, demonstrating its superior efficiency, accuracy ; and a wide range of applicability. The present theory, which is derived from the virtual work principle, is well-suited for developing computationally efficient CO-continuous finite elements, and is thus appropriate for the analysis and design of high-performance load-bearing aerospace structures.

Ultrathin and Ion-Selective Janus Membranes for High-Performance Osmotic Energy Conversion.

PubMed

Zhang, Zhen; Sui, Xin; Li, Pei; Xie, Ganhua; Kong, Xiang-Yu; Xiao, Kai; Gao, Longcheng; Wen, Liping; Jiang, Lei

2017-07-05

The osmotic energy existing in fluids is recognized as a promising "blue" energy source that can help solve the global issues of energy shortage and environmental pollution. Recently, nanofluidic channels have shown great potential for capturing this worldwide energy because of their novel transport properties contributed by nanoconfinement. However, with respect to membrane-scale porous systems, high resistance and undesirable ion selectivity remain bottlenecks, impeding their applications. The development of thinner, low-resistance membranes, meanwhile promoting their ion selectivity, is a necessity. Here, we engineered ultrathin and ion-selective Janus membranes prepared via the phase separation of two block copolymers, which enable osmotic energy conversion with power densities of approximately 2.04 W/m 2 by mixing natural seawater and river water. Both experiments and continuum simulation help us to understand the mechanism for how membrane thickness and channel structure dominate the ion transport process and overall device performance, which can serve as a general guiding principle for the future design of nanochannel membranes for high-energy concentration cells.

Durable polydopamine-coated porous sulfur core-shell cathode for high performance lithium-sulfur batteries

NASA Astrophysics Data System (ADS)

Deng, Yuanfu; Xu, Hui; Bai, Zhaowen; Huang, Baoling; Su, Jingyang; Chen, Guohua

2015-12-01

Lithium-sulfur batteries show fascinating potential for advanced energy system due to their high specific capacity, low-cost, and environmental benignity. However, their wide applications have been plagued by low coulombic efficiency, fast capacity fading and poor rate performance. Herein, a facile method for preparation of S@PDA (PDA = polydopamine) composites with core-shell structure and good electrochemical performance as well as the First-Principles calculations on the interactions of PDA and polysulfides are reported. Taking the advantages of the core-shell structure with porous sulfur core, the high mechanical flexibility of PDA for accommodating the volumetric variation during the discharge/charge processes, the good lithium ion conductivity and the strong chemical interactions between the nitrogen/oxygen atoms with lone electron pair and lithium polysulfides for alleviating their dissolution, the S@PDA composites exhibit high discharge capacities at different current densities (1048 and 869 mAh g-1 at 0.2 and 0.8 A g-1, respectively) and excellent capacity retention capability. A capacity decay as low as 0.021% per cycle and an average coulombic efficiency of 98.5% is observed over a long-term cycling of 890 cycles at 0.8 A g-1. The S@PDA electrode has great potential as a low-cost cathode in high energy Li-S batteries.

Spaceborne receivers: Basic principles

NASA Technical Reports Server (NTRS)

Stacey, J. M.

1984-01-01

The underlying principles of operation of microwave receivers for space observations of planetary surfaces were examined. The design philosophy of the receiver as it is applied to operate functionally as an efficient receiving system, the principle of operation of the key components of the receiver, and the important differences among receiver types are explained. The operating performance and the sensitivity expectations for both the modulated and total power receiver configurations are outlined. The expressions are derived from first principles and are developed through the important intermediate stages to form practicle and easily applied equations. The transfer of thermodynamic energy from point to point within the receiver is illustrated. The language of microwave receivers is applied statistics.

Wireless and chip-less passive radiation sensors for high dose monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Debourg, E.; Aubert, H.; Pons, P.

The safety of nuclear infrastructures may involve the monitoring of many parameters in harsh environments (high radiation level, high temperature, high pressure,..). If technological solutions exist for transducers part in such environments, the electronic part used in reader is not appropriate and still a challenging task. Well-known solutions to remove the electronic part from the harsh environment consist of connecting the transducer and the reader by long electrical wires or performing ex situ remote sensing. However wires may practically be difficult to implement while ex situ measurements are not compatible with on line monitoring. Wireless and passive sensors working inmore » harsh environments could be an appropriate solution for the remote sensing of critical parameters. Passive sensors without electronics in the sensing unit are available (e.g., SAW sensors) but they suffer from short reading range (typically lower than 10 meters). In order to overcome this range limitation a new class of electromagnetic transducers was developed in the mid-2000's. The operating principle is based on the modification of the properties of high-frequency (>> 1 GHz) passive electromagnetic devices by the quantity to be measured. Based on this principle a wide range of sensing properties can be addressed and a large number of materials can be chosen. Moreover the use of high frequency allows reducing the size of the sensor elements (antenna, transducer) and enhancing the immunity to multi-path. Several principles of RF transducers have been already validated by LAAS-CNRS (e;g; pressure, temperature, stress) as well as radar-based solution for the wireless long-range sensors interrogation. The sensor dosimeter exploit here the known property of Hydrogen-Pressure Dosimeters (HPD) for which the polymer material dehydrogenates under nuclear irradiation. The transducer principle is described. The irradiation will generate the out-gazing (hydrogen) of the polymer inside a micro-chamber. The resulting overpressure leads to the deflection of a silicon membrane which modifies the resonant frequency of the RF resonator. Tests structures have been designed in order to quantify the HDPE out-gazing inside a micro-cavity by measuring the deflection of a boss silicon membrane with a mechanical profiler. A specific set up using interferometry method has been also developed to evaluate the pressure generated inside the micro-cavity. The procedure consists in applying a pressure that pushes the membrane to recover a flat membrane. This condition is monitored thanks to the extinction of the Newton rings. Irradiations have been performed up to 30 kGy using 6 MeV focused e-beam providing by electron accelerator. Membrane deflection and generated pressure around 0.2 μm/mg{sub HDPE}/kGy and 70 mbar/mg{sub HDPE}/kGy has been obtained for a 70 μm thick membrane. In order to characterize the hermetic sealing of the micro-chamber under hydrogen over-pressure, membrane deflection after irradiation has been recorded during 50 days. The variations of membrane deflection are randomly distributed and generally lower than ±5%, showing a good hermeticity during this period. (authors)« less

Quality Management in U.S. High Schools: Evidence from the Field.

ERIC Educational Resources Information Center

Detert, James R.; Bauerly Kopel, Michelle E.; Mauriel, John J.; Jenni, Roger W.

2000-01-01

Reports on a longitudinal study examining implementation of a Quality Management reform based on Deming's seven principles. Interview and survey data from a national sample of purposefully chosen high schools show limited results as to teachers' effective use and institutionalization of TQM principles. The principal's role is critical. (Contains…

Do High School Chemistry Examinations Inhibit Deeper Level Understanding of Dynamic Reversible Chemical Reactions?

ERIC Educational Resources Information Center

Wheeldon, R.; Atkinson, R.; Dawes, A.; Levinson, R.

2012-01-01

Background and purpose: Chemistry examinations can favour the deployment of algorithmic procedures like Le Chatelier's Principle (LCP) rather than reasoning using chemical principles. This study investigated the explanatory resources which high school students use to answer equilibrium problems and whether the marks given for examination answers…