Epidemic failure detection and consensus for extreme parallelism

DOE PAGES

Katti, Amogh; Di Fatta, Giuseppe; Naughton, Thomas; ...

2017-02-01

Future extreme-scale high-performance computing systems will be required to work under frequent component failures. The MPI Forum s User Level Failure Mitigation proposal has introduced an operation, MPI Comm shrink, to synchronize the alive processes on the list of failed processes, so that applications can continue to execute even in the presence of failures by adopting algorithm-based fault tolerance techniques. This MPI Comm shrink operation requires a failure detection and consensus algorithm. This paper presents three novel failure detection and consensus algorithms using Gossiping. The proposed algorithms were implemented and tested using the Extreme-scale Simulator. The results show that inmore » all algorithms the number of Gossip cycles to achieve global consensus scales logarithmically with system size. The second algorithm also shows better scalability in terms of memory and network bandwidth usage and a perfect synchronization in achieving global consensus. The third approach is a three-phase distributed failure detection and consensus algorithm and provides consistency guarantees even in very large and extreme-scale systems while at the same time being memory and bandwidth efficient.« less

Carbon nanotube transistor based high-frequency electronics

NASA Astrophysics Data System (ADS)

Schroter, Michael

At the nanoscale carbon nanotubes (CNTs) have higher carrier mobility and carrier velocity than most incumbent semiconductors. Thus CNT based field-effect transistors (FETs) are being considered as strong candidates for replacing existing MOSFETs in digital applications. In addition, the predicted high intrinsic transit frequency and the more recent finding of ways to achieve highly linear transfer characteristics have inspired investigations on analog high-frequency (HF) applications. High linearity is extremely valuable for an energy efficient usage of the frequency spectrum, particularly in mobile communications. Compared to digital applications, the much more relaxed constraints for CNT placement and lithography combined with already achieved operating frequencies of at least 10 GHz for fabricated devices make an early entry in the low GHz HF market more feasible than in large-scale digital circuits. Such a market entry would be extremely beneficial for funding the development of production CNTFET based process technology. This talk will provide an overview on the present status and feasibility of HF CNTFET technology will be given from an engineering point of view, including device modeling, experimental results, and existing roadblocks.

Normal-incidence EXtreme-Ultraviolet imaging Spectrometer - NEXUS

NASA Astrophysics Data System (ADS)

Dere, K. P.

2003-05-01

NEXUS is the result of a breakthrough optical design that incorporates new technologies to achieve high optical throughput at high spatial (1 arcsec) and spectral (1-2 km s-1) resolution over a wide field of view in an optimal extreme-ultraviolet spectral band. This achievement was made possible primarily by two technical developments. First, a coating of boron-carbide deposited onto a layer of iridium provided a greatly enhanced reflectivity at EUV wavelengths that would enable NEXUS to observe the Sun over a wide temperature range at high cadence. The reflectivity of these coatings have been measured and demonstrated in the laboratory. The second key development was the use of a variable-line-spaced toroidal grating spectrometer. The spectrometer design allowed the Sun to be imaged at high spatial and spectral resolution along a 1 solar radius-long slit and over a wavelength range from 450 to 800 Å, nearly an entire spectral order. Because the spectrograph provided a magnification of about a factor of 6, only 2 optical elements are required to achieved the desired imaging performance. Throughput was enhanced by the use of only 2 reflections. The could all be accomodated within a total instrument length of 1.5m. We would like to acknowledge support from ONR

Design of a prototype position actuator for the primary mirror segments of the European Extremely Large Telescope

NASA Astrophysics Data System (ADS)

Jiménez, A.; Morante, E.; Viera, T.; Núñez, M.; Reyes, M.

2010-07-01

European Extremely Large Telescope (E-ELT) based in 984 primary mirror segments achieving required optical performance; they must position relatively to adjacent segments with relative nanometer accuracy. CESA designed M1 Position Actuators (PACT) to comply with demanding performance requirements of EELT. Three PACT are located under each segment controlling three out of the plane degrees of freedom (tip, tilt, piston). To achieve a high linear accuracy in long operational displacements, PACT uses two stages in series. First stage based on Voice Coil Actuator (VCA) to achieve high accuracies in very short travel ranges, while second stage based on Brushless DC Motor (BLDC) provides large stroke ranges and allows positioning the first stage closer to the demanded position. A BLDC motor is used achieving a continuous smoothly movement compared to sudden jumps of a stepper. A gear box attached to the motor allows a high reduction of power consumption and provides a great challenge for sizing. PACT space envelope was reduced by means of two flat springs fixed to VCA. Its main characteristic is a low linear axial stiffness. To achieve best performance for PACT, sensors have been included in both stages. A rotary encoder is included in BLDC stage to close position/velocity control loop. An incremental optical encoder measures PACT travel range with relative nanometer accuracy and used to close the position loop of the whole actuator movement. For this purpose, four different optical sensors with different gratings will be evaluated. Control strategy show different internal closed loops that work together to achieve required performance.

van Hove Singularities and Spectral Smearing in High Temperature Superconducting H3S

NASA Astrophysics Data System (ADS)

Quan, Yundi; Pickett, Warren E.

The superconducting phase of hydrogen sulfide at Tc=200 K observed by Drozdov and collaborators at pressures around 200 GPa is simple bcc Im 3 m H3S reopens questions about what is achievable in high Tc. The various ''extremes'' that are involved - pressure, implying extreme reduction of volume, extremely high H phonon energy scale around 1400K, extremely high temperature for a superconductor - necessitate a close look at new issues raised by these characteristics in relation to high Tc. We have applied first principles methods to analyze the H3S electronic structure, particularly the van Hove singularities (vHs) and the effect of sulfur. Focusing on the two closely spaced vHs near the Fermi level that give rise to the impressively sharp peak in the density of states, the implications of strong coupling Migdal-Eliashberg theory are assessed. The electron spectral density smearing due to virtual phonon emission and absorption, as done in earlier days for A15 superconductors, must be included explicitly to obtain accurate theoretical predictions and a correct understanding. Means for increasing Tc in H3S-like materials will be mentioned. NSF DMR Grant 1207622.

Turning a low Q fiber resonator into a high-sensitivity displacement sensor using slow light concepts

NASA Astrophysics Data System (ADS)

Bravo, Mikel; Angulo-Vinuesa, Xabier; Martin-Lopez, Sonia; Lopez-Amo, Manuel; Gonzalez-Herraez, Miguel

2013-05-01

High-Q resonators have been widely used for sensing purposes. High Q factors normally lead to sharp spectral peaks which accordingly provide a strong sensitivity in spectral interrogation methods. In this work we employ a low-Q ring resonator to develop a high sensitivity sub-micrometric resolution displacement sensor. We use the slow-light effects occurring close to the critical coupling regime to achieve high sensitivity in the device. By tuning the losses in the cavity close to the critical coupling, extremely high group delay variations can be achieved, which in turn introduce strong enhancements of the absorption of the structure. We first validate the concept using an Optical Vector Analyzer (OVA) and then we propose a simple functional scheme for achieving a low-cost interrogation of this kind of sensors.

A maximally stable extremal region based scene text localization method

NASA Astrophysics Data System (ADS)

Xiao, Chengqiu; Ji, Lixin; Gao, Chao; Li, Shaomei

2015-07-01

Text localization in natural scene images is an important prerequisite for many content-based image analysis tasks. This paper proposes a novel text localization algorithm. Firstly, a fast pruning algorithm is designed to extract Maximally Stable Extremal Regions (MSER) as basic character candidates. Secondly, these candidates are filtered by using the properties of fitting ellipse and the distribution properties of characters to exclude most non-characters. Finally, a new extremal regions projection merging algorithm is designed to group character candidates into words. Experimental results show that the proposed method has an advantage in speed and achieve relatively high precision and recall rates than the latest published algorithms.

EUNIS; Extreme-Ultraviolet Normal-Incidence Spectrometer

NASA Technical Reports Server (NTRS)

Thomas, Roger J.; Davila, Joseph M.; Fisher, Richard R. (Technical Monitor)

2001-01-01

GSFC is in the process of assembling an Extreme-Ultraviolet Normal Incidence Spectrometer called EUNIS, to be flown as a sounding rocket payload. The instrument builds on the many technical innovations pioneered by our highly successful SERTS experiment, which has now flown a total of ten times, most recently last summer. The new design will have somewhat improved spatial and spectral resolutions, as well as two orders of magnitude greater sensitivity, permitting high signal/noise EUV spectroscopy with a temporal resolution near 1 second for the first time ever. In order to achieve such high time cadence, a novel detector system is being developed, based on Active-Pixel-Sensor electronics, a key component of our design.

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

Katti, Amogh; Di Fatta, Giuseppe; Naughton, Thomas

Future extreme-scale high-performance computing systems will be required to work under frequent component failures. The MPI Forum s User Level Failure Mitigation proposal has introduced an operation, MPI Comm shrink, to synchronize the alive processes on the list of failed processes, so that applications can continue to execute even in the presence of failures by adopting algorithm-based fault tolerance techniques. This MPI Comm shrink operation requires a failure detection and consensus algorithm. This paper presents three novel failure detection and consensus algorithms using Gossiping. The proposed algorithms were implemented and tested using the Extreme-scale Simulator. The results show that inmore » all algorithms the number of Gossip cycles to achieve global consensus scales logarithmically with system size. The second algorithm also shows better scalability in terms of memory and network bandwidth usage and a perfect synchronization in achieving global consensus. The third approach is a three-phase distributed failure detection and consensus algorithm and provides consistency guarantees even in very large and extreme-scale systems while at the same time being memory and bandwidth efficient.« less

Bathed, Strained, Attenuated, Annihilated: Towards Quantum Optomechanics

NASA Astrophysics Data System (ADS)

Pepper, Brian Jeffrey

The field of optomechanics studies tiny devices that can be pushed mechanically by light. It is an extremely promising avenue towards tests of quantum mechanics on a macroscopic scale, by transferring quantum states of light to nano- or micromechanical objects. This dissertation concerns a long term research program to create quantum superpositions of a macroscopic mirror in an optomechanical cavity. This dissertation has two broad thrusts. The first focuses on microfabrication of a new type of device called optomechanical trampoline resonators, consisting of a small mirror on a cross-shaped tensed silicon nitride membrane. Devices have been fabricated with high mechanical and optical quality, including a 300 kHz device with quality factor 480,000, as well as a device of optical finesse 107,000. These devices are well into the sideband-resolved regime and suitable for optical cooling to the quantum ground state. One such device has been optically cooled to approximately 10 phonons. The second major thrust is theoretical. Creating a macroscopic superposition is a challenging problem, requiring optical cooling to the ground state, strong coupling, extremely high optical finesse and extremely low frequency. A realistic assessment of achievable parameters indicates that it is possible to achieve ground state cooling or strong coupling, but not both. This dissertation proposes a new technique using postselection to achieve macroscopic superpositions with only weak coupling. This relaxes some of the required parameters by orders of magnitude. Prospects for observing hypothetical novel decoherence mechanisms are also discussed.

Extreme Terrestrial Environments: Life in Thermal Stress and Hypoxia. A Narrative Review.

PubMed

Burtscher, Martin; Gatterer, Hannes; Burtscher, Johannes; Mairbäurl, Heimo

2018-01-01

Living, working and exercising in extreme terrestrial environments are challenging tasks even for healthy humans of the modern new age. The issue is not just survival in remote environments but rather the achievement of optimal performance in everyday life, occupation, and sports. Various adaptive biological processes can take place to cope with the specific stressors of extreme terrestrial environments like cold, heat, and hypoxia (high altitude). This review provides an overview of the physiological and morphological aspects of adaptive responses in these environmental stressors at the level of organs, tissues, and cells. Furthermore, adjustments existing in native people living in such extreme conditions on the earth as well as acute adaptive responses in newcomers are discussed. These insights into general adaptability of humans are complemented by outcomes of specific acclimatization/acclimation studies adding important information how to cope appropriately with extreme environmental temperatures and hypoxia.

Extreme Terrestrial Environments: Life in Thermal Stress and Hypoxia. A Narrative Review

PubMed Central

Burtscher, Martin; Gatterer, Hannes; Burtscher, Johannes; Mairbäurl, Heimo

2018-01-01

Living, working and exercising in extreme terrestrial environments are challenging tasks even for healthy humans of the modern new age. The issue is not just survival in remote environments but rather the achievement of optimal performance in everyday life, occupation, and sports. Various adaptive biological processes can take place to cope with the specific stressors of extreme terrestrial environments like cold, heat, and hypoxia (high altitude). This review provides an overview of the physiological and morphological aspects of adaptive responses in these environmental stressors at the level of organs, tissues, and cells. Furthermore, adjustments existing in native people living in such extreme conditions on the earth as well as acute adaptive responses in newcomers are discussed. These insights into general adaptability of humans are complemented by outcomes of specific acclimatization/acclimation studies adding important information how to cope appropriately with extreme environmental temperatures and hypoxia. PMID:29867589

Strategies That Challenge: Exploring the Use of Differentiated Assessment to Challenge High-Achieving Students in Large Enrolment Undergraduate Cohorts

ERIC Educational Resources Information Center

Varsavsky, Cristina; Rayner, Gerry

2013-01-01

Academics teaching large and highly diverse classes are familiar with the inevitable effect this has on promulgating teaching and assessment practices to "middle of the distribution", thus ignoring the distribution extremes. Although the literature documents a wide range of strategies for supporting poor-performing students in large…

Innovative diffraction gratings for high-resolution resonant inelastic soft x-ray scattering spectroscopy

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

Voronov, D.L.; Warwick, T.; Gullikson, E. M.

2016-07-27

High-resolution Resonant Inelastic X-ray Scattering (RIXS) requires diffraction gratings with very exacting characteristics. The gratings should provide both very high dispersion and high efficiency which are conflicting requirements and extremely challenging to satisfy in the soft x-ray region for a traditional grazing incidence geometry. To achieve high dispersion one should increase the groove density of a grating; this however results in a diffraction angle beyond the critical angle range and results in drastic efficiency loss. The problem can be solved by use of multilayer coated blazed gratings (MBG). In this work we have investigated the diffraction characteristics of MBGs viamore » numerical simulations and have developed a procedure for optimization of grating design for a multiplexed high resolution imaging spectrometer for RIXS spectroscopy to be built in sector 6 at the Advanced Light Source (ALS). We found that highest diffraction efficiency can be achieved for gratings optimized for 4{sup th} or 5{sup th} order operation. Fabrication of such gratings is an extremely challenging technological problem. We present a first experimental prototype of these gratings and report its performance. High order and high line density gratings have the potential to be a revolutionary new optical element that should have great impact in the area of soft x-ray RIXS.« less

Safe surgical technique for associated acetabular fractures

PubMed Central

2013-01-01

Associated acetabular fractures are challenging injuries to manage. The complex surgical approaches and the technical difficulty in achieving anatomical reduction imply that the learning curve to achieve high-quality care of patients with such challenging injuries is extremely steep. This first article in the Journal’s “Safe Surgical Technique” section presents the standard surgical care, in conjunction with intraoperative tips and tricks, for the safe management of all subgroups of associated acetabular fractures. PMID:23414782

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

Wei, D. T.

Ion beam interference coating (IBIC) is a sputter-deposition process for multiple layers of optical thin films employing a Kaufman gun. It has achieved coatings of extremely low optical loss and high mechanical strength. It has many potential applications for a wide spectral range. This coating process is described in terms of principle, fabrication procedure, and optical measurements. Some discussions follow the history and outlooks of IBIC with emphasis on how to achieve low loss and on the throughput improvements.

Extreme-scale Algorithms and Solver Resilience

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

Dongarra, Jack

A widening gap exists between the peak performance of high-performance computers and the performance achieved by complex applications running on these platforms. Over the next decade, extreme-scale systems will present major new challenges to algorithm development that could amplify this mismatch in such a way that it prevents the productive use of future DOE Leadership computers due to the following; Extreme levels of parallelism due to multicore processors; An increase in system fault rates requiring algorithms to be resilient beyond just checkpoint/restart; Complex memory hierarchies and costly data movement in both energy and performance; Heterogeneous system architectures (mixing CPUs, GPUs,more » etc.); and Conflicting goals of performance, resilience, and power requirements.« less

Exciplex-triplet energy transfer: A new method to achieve extremely efficient organic light-emitting diode with external quantum efficiency over 30% and drive voltage below 3 V

NASA Astrophysics Data System (ADS)

Seo, Satoshi; Shitagaki, Satoko; Ohsawa, Nobuharu; Inoue, Hideko; Suzuki, Kunihiko; Nowatari, Hiromi; Yamazaki, Shunpei

2014-04-01

A novel approach to enhance the power efficiency of an organic light-emitting diode (OLED) by employing energy transfer from an exciplex to a phosphorescent emitter is reported. It was found that excitation energy of an exciplex formed between an electron-transporting material with a π-deficient quinoxaline moiety and a hole-transporting material with aromatic amine structure can be effectively transferred to a phosphorescent iridium complex in an emission layer of a phosphorescent OLED. Moreover, such an exciplex formation increases quantum efficiency and reduces drive voltage. A highly efficient, low-voltage, and long-life OLED based on this energy transfer is also demonstrated. This OLED device exhibited extremely high external quantum efficiency of 31% even without any attempt to enhance light outcoupling and also achieved a low drive voltage of 2.8 V and a long lifetime of approximately 1,000,000 h at a luminance of 1,000 cd/m2.

A COMPARISON OF MASS MEDIA USAGE BY JUNIOR HIGH SCHOOL PUPILS OF EXTREME EDUCATIONAL ACHIEVEMENT AND MENTAL ABILITY.

ERIC Educational Resources Information Center

KINSELLA, PAUL J.

THE MOTION PICTURE, RADIO, AND TELEVISION ACTIVITIES AND INTERESTS OF JUNIOR HIGH SCHOOL STUDENTS WERE ASCERTAINED TO DETERMINE POSSIBILITIES FOR BETTER EDUCATIONAL UTILIZATION OF THESE MEDIA. THIS PROJECT WAS CONDUCTED AS A SUPPLEMENTARY ACTIVITY TO COOPERATIVE RESEARCH PROJECT 367, "A STUDY OF INTERESTS OF CHILDREN AND YOUTH" (ED 002…

Neural manufacturing: a novel concept for processing modeling, monitoring, and control

NASA Astrophysics Data System (ADS)

Fu, Chi Y.; Petrich, Loren; Law, Benjamin

1995-09-01

Semiconductor fabrication lines have become extremely costly, and achieving a good return from such a high capital investment requires efficient utilization of these expensive facilities. It is highly desirable to shorten processing development time, increase fabrication yield, enhance flexibility, improve quality, and minimize downtime. We propose that these ends can be achieved by applying recent advances in the areas of artificial neural networks, fuzzy logic, machine learning, and genetic algorithms. We use the term neural manufacturing to describe such applications. This paper describes our use of artificial neural networks to improve the monitoring and control of semiconductor process.

Health inequities, environmental insecurity and the attainment of the millennium development goals in sub-Saharan Africa: the case study of Zambia.

PubMed

Anyangwe, Stella C E; Mtonga, Chipayeni; Chirwa, Ben

2006-09-01

The United Nations Millennium Development Goals (MDGs) are a series of 8 goals and 18 targets aimed at ending extreme poverty by 2015, and there are 48 quantifiable indicators for monitoring the process. Most of the MDGs are health or health-related goals. Though the MDGs might sound ambitious, it is imperative that the world, and sub-Saharan Africa in particular, wake up to the persistent and unacceptably high rates of extreme poverty that populations live in, and find lasting solutions to age-old problems. Extreme poverty is a cause and consequence of low income, food insecurity and hunger, education and gender inequities, high disease burden, environmental degradation, insecure shelter, and lack of access to safe drinking water and basic sanitation. It is also directly linked to unsound governance and inequitable distribution of public wealth. While many regions in the world will strive to attain the MDGs by 2015, most of the countries in sub-Saharan Africa, with major human development challenges associated with socio-economic disparities, will not. Zambia's MDG progress reports of 2003 and 2005 show that despite laudable political commitment and some advances made towards achieving universal primary education, gender equality, improvement of child health and management of the HIV/AIDS epidemic, it is not likely that Zambia will achieve even half of the goals. Zambia's systems have been weakened by high disease burden and excess mortality, natural and man-made environmental threats and some negative effects of globalization such as huge external debt, low world prices for commodities and the human resource "brain drain", among others. Urgent action must follow political will, and some tried and tested strategies or "quick wins" that have been proven to produce high positive impact in the short term, need to be rapidly embarked upon by Zambia and other countries in sub-Saharan Africa if they are to achieve the Millennium Development Goals.

Achieving polydimethylsiloxane/carbon nanotube (PDMS/CNT) composites with extremely low dielectric loss and adjustable dielectric constant by sandwich structure

NASA Astrophysics Data System (ADS)

Fan, Benhui; Liu, Yu; He, Delong; Bai, Jinbo

2018-01-01

Sandwich-structured composites of polydimethylsiloxane/carbon nanotube (PDMS/CNT) bulk between two neat PDMS thin films with different thicknesses are prepared by the spin-coating method. Taking advantage of CNT's percolation behavior, the composite keeps relatively high dielectric constant (ɛ' = 40) at a low frequency (at 100 Hz). Meanwhile, due to the existence of PDMS isolated out-layers which limits the conductivity of the composite, the composite maintains an extremely low dielectric loss (tan δ = 0.01) (at 100 Hz). Moreover, the same matrix of the out-layer and bulk can achieve excellent interfacial adhesion, and the thickness of the coating layer can be controlled by a multi-cycle way. Then, based on the experimental results, the calculation combining the percolation theory and core-shell model is used to analyze the thickness effect of the coating layer on ɛ'. The obtained relationship between the ɛ' of the composite and the thickness of the coating layer can help to optimize the sandwich structure in order to obtain the adjustable ɛ' and the extremely low tan δ.

A method for Removing Surface Contamination on Ultra-pure Copper Spectrometer Components

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

Hoppe, Eric W.; Seifert, Allen; Aalseth, Craig E.

Spectrometers for the lowest-level radiometric measurements require materials of extreme radiopurity. Measurements of rare nuclear decays, e.g. neutrinoless double-beta decay, can require construction and shielding materials with bulk radiopurity reaching one micro-Becquerel per kilogram or less. When such extreme material purity is achieved, surface contamination, particularly solid daughters in the natural radon decay chains, can become the limiting background. High-purity copper is an important material for ultra-low-background spectrometers and thus is the focus of this work. A method for removing surface contamination at very low levels without attacking the bulk material is described. An assay method using a low-background proportionalmore » counter made of the material under examination is employed, and the resulting preliminary result of achievable surface contamination levels is presented.« less

Expert consensus on facilitators and barriers to return-to-work following surgery for non-traumatic upper extremity conditions: a Delphi study.

PubMed

Peters, S E; Johnston, V; Ross, M; Coppieters, M W

2017-02-01

This Delphi study aimed to reach consensus on important facilitators and barriers for return-to-work following surgery for non-traumatic upper extremity conditions. In Round 1, experts ( n = 42) listed 134 factors, which were appraised in Rounds 2 and 3. Consensus (⩾85% agreement) was achieved for 13 facilitators (high motivation to return-to-work; high self-efficacy for return-to-work and recovery; availability of modified/alternative duties; flexible return-to-work arrangements; positive coping skills; limited heavy work exertion; supportive return-to-work policies; supportive supervisor/management; no catastrophic thinking; no fear avoidance to return-to-work; no fear avoidance to pain/activity; return to meaningful work duties; high job satisfaction) and six barriers (mood disorder diagnosis; pain/symptoms at more than one musculoskeletal site; heavy upper extremity exertions at work; lack of flexible return-to-work arrangements; lack of support from supervisor/management; high level of pain catastrophizing). Future prognostic studies are required to validate these biopsychosocial factors to further improve return-to-work outcomes. V.

Achieving high aspect ratio wrinkles by modifying material network stress.

PubMed

Chen, Yu-Cheng; Wang, Yan; McCarthy, Thomas J; Crosby, Alfred J

2017-06-07

Wrinkle aspect ratio, or the amplitude divided by the wavelength, is hindered by strain localization transitions when an increasing global compressive stress is applied to synthetic material systems. However, many examples from living organisms show extremely high aspect ratios, such as gut villi and flower petals. We use three experimental approaches to demonstrate that these high aspect ratio structures can be achieved by modifying the network stress in the wrinkle substrate. We modify the wrinkle stress and effectively delay the strain localization transition, such as folding, to larger aspect ratios by using a zero-stress initial wavy substrate, creating a secondary network with post-curing, or using chemical stress relaxation materials. A wrinkle aspect ratio as high as 0.85, almost three times higher than common values of synthetic wrinkles, is achieved, and a quantitative framework is presented to provide understanding the different strategies and predictions for future investigations.

Mindful Organizing as a Paradigm to Develop Managers

ERIC Educational Resources Information Center

Gebauer, Annette

2013-01-01

How can managers prepare for extreme but exceptional events and for the challenge of managing complexity and uncertainty in their daily business? Confronted with the challenge of achieving high and reliable performance in risk-prone, fast-paced, and unpredictable environments, managers and management scholars can learn a lot from the organizing…

The Subaru Coronagraphic Extreme AO Project: Progress and Upgrades

NASA Astrophysics Data System (ADS)

Jovanovic, Nemanja; Martinache, F.; Guyon, O.; Clergeon, C.; Garrel, V.

2013-01-01

The Subaru Coronagraphic Extreme AO (SCExAO) instrument consists of a high performance Phase Induced Amplitude Apodisation (PIAA) coronagraph combined with an extreme Adaptive Optics (AO) system operating in the near-infrared (H band). The extreme AO system driven by the 2000 element deformable mirror will allow for Strehl ratios>90% to be achieved in the H-band when it goes closed loop. This makes the SCExAO instrument a powerful platform for high contrast imaging down to angular separations of the order of 1 λ/D. In this paper we report on the recent progress in regards to the development of the instrument, which includes the addition of a visible bench that makes use of the light at shorter wavelengths not currently utilized by SCExAO and closing the loop on the tip/tilt wavefront sensor. We will also discuss two exciting guest instruments which will expand the capabilities of SCExAO over the next few years; namely CHARIS which is a integral field spectrograph as well as VAMPIRES, a visible aperture masking experiment based on polarimetric analysis of circumstellar disks.

Extreme Environment Capable, Modular and Scalable Power Processing Unit for Solar Electric Propulsion

NASA Technical Reports Server (NTRS)

Carr, Gregory A.; Iannello, Christopher J.; Chen, Yuan; Hunter, Don J.; DelCastillo, Linda; Bradley, Arthur T.; Stell, Christopher; Mojarradi, Mohammad M.

2013-01-01

This paper is to present a concept of a modular and scalable High Temperature Boost (HTB) Power Processing Unit (PPU) capable of operating at temperatures beyond the standard military temperature range. The various extreme environments technologies are also described as the fundamental technology path to this concept. The proposed HTB PPU is intended for power processing in the area of space solar electric propulsion, where reduction of in-space mass and volume are desired, and sometimes even critical, to achieve the goals of future space flight missions. The concept of the HTB PPU can also be applied to other extreme environment applications, such as geothermal and petroleum deep-well drilling, where higher temperature operation is required.

Extreme Environment Capable, Modular and Scalable Power Processing Unit for Solar Electric Propulsion

NASA Technical Reports Server (NTRS)

Carr, Gregory A.; Iannello, Christopher J.; Chen, Yuan; Hunter, Don J.; Del Castillo, Linda; Bradley, Arthur T.; Stell, Christopher; Mojarradi, Mohammad M.

2013-01-01

This paper is to present a concept of a modular and scalable High Temperature Boost (HTB) Power Processing Unit (PPU) capable of operating at temperatures beyond the standard military temperature range. The various extreme environments technologies are also described as the fundamental technology path to this concept. The proposed HTB PPU is intended for power processing in the area of space solar electric propulsion, where the reduction of in-space mass and volume are desired, and sometimes even critical, to achieve the goals of future space flight missions. The concept of the HTB PPU can also be applied to other extreme environment applications, such as geothermal and petroleum deep-well drilling, where higher temperature operation is required.

Optimizing pulse shaping and zooming for acceleration to high velocities and fusion neutron production on the Nike laser

NASA Astrophysics Data System (ADS)

Karasik, Max; Weaver, J. L.; Aglitskiy, Y.; Zalesak, S. T.; Velikovich, A. L.; Oh, J.; Obenschain, S. P.; Arikawa, Y.; Watari, T.

2010-11-01

We will present results from follow-on experiments to the record-high velocities of 1000 km/s achieved on Nike [Karasik et al., Phys. Plasmas 17, 056317 (2010) ], in which highly accelerated planar foils of deuterated polystyrene were made to collide with a witness foil to produce extreme shock pressures and result in heating of matter to thermonuclear temperatures. Still higher velocities and higher target densities are required for impact fast ignition. The aim of these experiments is shaping the driving pulse to minimize shock heating of the accelerated target and using the focal zoom capability of Nike to achieve higher densities and velocities. Spectroscopic measurements of electron temperature achieved upon impact will complement the neutron time-of-flight ion temperature measurement. Work is supported by US DOE and Office of Naval Research.

Weaving Whole Cloth: The Nurture of a Highly Intelligent Child. What Is It Like To Live with a Highly Intelligent Child?

ERIC Educational Resources Information Center

Sargeant, Hope

2000-01-01

The parent of an extremely intelligent child discusses what it is like to live with a child who exhibits a different web of cognition, perception, intuition, and mental processing; the necessity of educational acceleration for learning to achieve and develop self-esteem; and the importance of challenging material in learning the satisfaction of…

The Extremes of the Bell Curve: Excellent and Poor School Performance and Risk for Severe Mental Disorders. Maudsley Series

ERIC Educational Resources Information Center

MacCabe, James H.

2010-01-01

It has long been claimed that there is a strong association between high intelligence, or exceptional creativity, and mental illness. In this book, James MacCabe investigates this claim, using evidence from Swedish population data. He finds evidence that children who achieve either exceptionally high, or very low grades at school, are at greater…

Early study on the application of Nexcera ultra low thermal expansion ceramic to space telescopes

NASA Astrophysics Data System (ADS)

Kamiya, Tomohiro; Sugawara, Jun; Mizutani, Tadahito; Yasuda, Susumu; Kitamoto, Kazuya

2017-09-01

Optical mirrors for space telescopes, which require high precision and high thermal stability, have commonly been made of glass materials such as ultra low expansion glass (e.g. ULE®) or extremely low expansion glassceramic (e.g. ZERODUR® or CLEARCERAM®). These materials have been well-known for their reliability due to their long history of achievements in many space applications.

Adiposity and Physical Activity Are Not Related to Academic Achievement in School-Aged Children

PubMed Central

LeBlanc, Monique M.; Martin, Corby K.; Han, Hongmei; Newton, Robert; Sothern, Melinda; Webber, Larry S.; Davis, Allison B.; Williamson, Donald A.

2012-01-01

Objective To investigate the hypotheses that in elementary school students: 1) adiposity and academic achievement are negatively correlated and 2) physical activity and academic achievement are positively correlated. Method Participants were 1963 children in fourth through sixth grades. Adiposity was assessed by calculating body mass index (BMI) percentile and percent body fat and academic achievement with statewide standardized tests in four content areas. Socioeconomic status and age were control variables. A subset of participants (n = 261) wore an accelerometer for three days to provide objective measurement of physical activity. Additionally, the association between weight status and academic achievement was examined by comparing children who could be classified as “extremely obese” and the rest of the sample, as well as comparing children who could be classified as normal weight, overweight, or obese. Extreme obesity was defined as >= 1.2 times the 95th percentile. Results Results indicated that there were no significant associations between adiposity or physical activity and achievement in students. No academic achievement differences were found between children with BMI percentiles within the extreme obesity range and those who did not fall within the extreme obesity classification. Additionally, no academic achievement differences were found for children with BMI percentiles within the normal weight, overweight, or obese ranges. Conclusion These results do not support the hypotheses that increased adiposity is associated with decreased academic achievement or that greater physical activity is related to improved achievement. However, these results are limited by methodological weaknesses, especially the use of cross-sectional data. PMID:22617499

High-efficiency collector design for extreme-ultraviolet and x-ray applications.

PubMed

Zocchi, Fabio E

2006-12-10

A design of a two-reflection mirror for nested grazing-incidence optics is proposed in which maximum overall reflectivity is achieved by making the two grazing-incidence angles equal for each ray. The design is proposed mainly for application to nonimaging collector optics for extreme-ultraviolet microlithography where the radiation emitted from a hot plasma source needs to be collected and focused on the illuminator optics. For completeness, the design of a double- reflection mirror with equal reflection angles is also briefly outlined for the case of an object at infinity for possible use in x-ray applications.

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

Katti, Amogh; Di Fatta, Giuseppe; Naughton III, Thomas J

Future extreme-scale high-performance computing systems will be required to work under frequent component failures. The MPI Forum's User Level Failure Mitigation proposal has introduced an operation, MPI_Comm_shrink, to synchronize the alive processes on the list of failed processes, so that applications can continue to execute even in the presence of failures by adopting algorithm-based fault tolerance techniques. This MPI_Comm_shrink operation requires a fault tolerant failure detection and consensus algorithm. This paper presents and compares two novel failure detection and consensus algorithms. The proposed algorithms are based on Gossip protocols and are inherently fault-tolerant and scalable. The proposed algorithms were implementedmore » and tested using the Extreme-scale Simulator. The results show that in both algorithms the number of Gossip cycles to achieve global consensus scales logarithmically with system size. The second algorithm also shows better scalability in terms of memory and network bandwidth usage and a perfect synchronization in achieving global consensus.« less

A narrow open tubular column for high efficiency liquid chromatographic separation

DOE PAGES

Chen, Huang; Yang, Yu; Qiao, Zhenzhen; ...

2018-01-01

We report a great feature of open tubular liquid chromatography when it is run using an extremely narrow ( e.g. , 2 μm inner diameter) open tubular column: more than 10 million plates per meter can be achieved in less than 10 min and under an elution pressure of ca. 20 bar.

Transition. Practice Perspectives--Highlighting Information on Deaf-Blindness. Number 4

ERIC Educational Resources Information Center

Malloy, Peggy; McGinnity, Betsy

2009-01-01

Finding a job, learning to live independently, and obtaining further education are important goals for all young adults as they leave high school. But achieving these goals is often extremely difficult for students who are deaf-blind. Limited or absent hearing and vision, difficulties with communication, and the frequent presence of additional…

Achievement, Poverty and Privatization in England: Policy and Evidence

ERIC Educational Resources Information Center

Wrigley, Terry

2012-01-01

For many years, England has been the epitome of high-stakes accountability, often playing leapfrog with the USA. It represents an extreme of centralized surveillance, with schools organized as a quasi-market and supervised through a punitive combination of external inspection, the use of test data to name and shame schools, and ultimately closure…

A narrow open tubular column for high efficiency liquid chromatographic separation

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

Chen, Huang; Yang, Yu; Qiao, Zhenzhen

We report a great feature of open tubular liquid chromatography when it is run using an extremely narrow ( e.g. , 2 μm inner diameter) open tubular column: more than 10 million plates per meter can be achieved in less than 10 min and under an elution pressure of ca. 20 bar.

Journeys through the valley of death: multimethod psychological assessment and personality transformation in long-term psychotherapy.

PubMed

Finn, Stephen E

2011-03-01

The Psychodynamic Diagnostic Manual (PDM Task Force, 2006) is based on the assumption that an in-depth understanding of clients' underlying emotional, personality, and interpersonal patterns will facilitate their treatment. In this article I show how such an understanding can be achieved through multimethod psychological assessment, and how useful such information can be in long-term psychotherapy with high-achieving, successful clients who struggle with forming and maintaining intimate relationships. Such treatments are extremely difficult, because when these clients attach to their psychotherapists, many of them temporarily become more symptomatic. I illustrate these points with a detailed account of my long-term therapy with a resilient but highly traumatized young man. Repeated use of the Minnesota Multiphasic Personality Disorder-2 (MMPI-2; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) and Rorschach with my client helped guide us in our work, and also helped create an important therapeutic "opening" into the underlying traumatic material. This and other experiences have convinced me that it is extremely useful for psychologists to have training in both assessment and psychotherapy.

Making structured metals transparency for broadband and wide-incidence-angle electromagnetic waves

NASA Astrophysics Data System (ADS)

Fan, Renhao; Peng, Ruwen; Huang, Xianrong; Wang, Mu

2014-03-01

Very recently, we have demonstrated that one-dimensional metallic gratings can become transparent and completely antireflective for extremely broadband electromagnetic (EM) waves under oblique incidence. However, the oblique-incidence geometry, is inconvenient for the technological applications. To overcome this drawback, here we instead use oblique metal gratings with optimal tilt angles to achieve normal-incidence broadband transparence for EM waves. Further we use two-dimensional periodic metallic cuboids to achieve broadband and broad-angle high transmission and antireflection. By introducing such metallic cuboids arrays into silicon solar cells, we find that high performance of light trapping in the cells can be obtained with a significant enhancement of the ultimate quantum efficiency. The structured metals, which achieve broadband and broad-angle high transmission for EM waves, may have many other potential applications, such as transparent conducting panels, white-beam polarizers, and stealth objects.

Enhancing protein to extremely high content in photosynthetic bacteria during biogas slurry treatment.

PubMed

Yang, Anqi; Zhang, Guangming; Meng, Fan; Lu, Pei; Wang, Xintian; Peng, Meng

2017-12-01

This work proposed a novel approach to achieve an extremely high protein content in photosynthetic bacteria (PSB) using biogas slurry as a culturing medium. The results showed the protein content of PSB could be enhanced strongly to 90% in the biogas slurry, which was much higher than reported microbial protein contents. The slurry was partially purified at the same time. Dark-aerobic was more beneficial than light-anaerobic condition for protein accumulation. High salinity and high ammonia of the biogas slurry were the main causes for protein enhancement. In addition, the biogas slurry provided a good buffer system for PSB to grow. The biosynthesis mechanism of protein in PSB was explored according to theoretical analysis. During biogas slurry treatment, the activities of glutamate synthase and glutamine synthetase were increased by 26.55%, 46.95% respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

SCExAO as a precursor to an ELT exoplanet direct imaging instrument

NASA Astrophysics Data System (ADS)

Jovanovic, Nemanja; Guyon, Olivier; Martinache, Frantz; Clergeon, Christophe; Singh, Garima; Vievard, Sebastien; Kudo, Tomoyuki; Garrel, Vincent; Norris, Barnaby; Tuthill, Peter; Stewart, Paul; Huby, Elsa; Perrin, Guy; Lacour, Sylvestre

2013-12-01

The Subaru Coronagraphic Extreme AO (SCExAO) instrument consists of a high performance Phase Induced Amplitude Apodisation (PIAA) coronagraph combined with an extreme Adaptive Optics (AO) system operating in the near-infrared (H band). The extreme AO system driven by the 2000 element deformable mirror will allow for Strehl ratios>90% to be achieved in the H-band when it goes closed loop. This makes the SCExAO instrument a powerful platform for high contrast imaging down to angular separations of the order of 1 lambda/D and an ideal testbed for exploring coronagraphic techniques for ELTs. In this paper we report on the recent progress in regards to the development of the instrument, which includes the addition of a visible bench that makes use of the light at shorter wavelengths not currently utilized by SCExAO and closing the loop on the tip/tilt wavefront sensor. We will also discuss several exciting guest instruments which will expand the capabilities of SCExAO over the next few years; namely CHARIS which is a integral field spectrograph as well as VAMPIRES, a visible aperture masking experiment based on polarimetric analysis of circumstellar disks. In addition we will elucidate the unique role extreme AO systems will play in enabling high precision radial velocity spectroscopy for the detection of small companions.

Predictive Modeling of Risk Associated with Temperature Extremes over Continental US

NASA Astrophysics Data System (ADS)

Kravtsov, S.; Roebber, P.; Brazauskas, V.

2016-12-01

We build an extremely statistically accurate, essentially bias-free empirical emulator of atmospheric surface temperature and apply it for meteorological risk assessment over the domain of continental US. The resulting prediction scheme achieves an order-of-magnitude or larger gain of numerical efficiency compared with the schemes based on high-resolution dynamical atmospheric models, leading to unprecedented accuracy of the estimated risk distributions. The empirical model construction methodology is based on our earlier work, but is further modified to account for the influence of large-scale, global climate change on regional US weather and climate. The resulting estimates of the time-dependent, spatially extended probability of temperature extremes over the simulation period can be used as a risk management tool by insurance companies and regulatory governmental agencies.

Extreme maternal education and preterm birth: time-to-event analysis of age and nativity-dependent risks.

PubMed

Auger, Nathalie; Abrahamowicz, Michal; Park, Alison L; Wynant, Willy

2013-01-01

Increasing numbers of women achieve extremely high education, but the association with preterm birth (PTB) is poorly understood, especially over the life course. We sought to determine how very high educational attainment is associated with PTB, and to assess differences by maternal age and nativity. Data included singleton live births to mothers aged ≥ 20 years in metropolitan areas of Québec, Canada, from 1995 to 2005 (n = 537,525). Hazard ratios of PTB (<37 gestational weeks) were estimated over the continuous range of education (0-30 years) according to maternal age (20-24, 25-29, 30-34, ≥ 35 years) and nativity in a flexible survival model. The relationship between education and PTB was not linear, but suggested that extremely high education was not as protective against PTB as slightly lower education. Education thresholds that offered maximum protection increased with maternal age, and were lower for Canadian-born (17-21 years of education) than foreign-born (22-25 years of education) mothers. Extremely high education did not confer more protection against PTB than slightly lower education, and associations varied over the life course. The threshold number of years of education most protective against PTB: (1) increased with maternal age, especially for Canadian-born mothers, and (2) was higher for foreign-born mothers. Copyright © 2013 Elsevier Inc. All rights reserved.

Socioeconomic Context and Emotional-Behavioral Achievement Links: Concurrent and Prospective Associations Among Low- and High-Income Youth

PubMed Central

Ansary, Nadia S.; McMahon, Thomas J.; Luthar, Suniya S.

2012-01-01

Temporal associations in the relationship between emotional-behavioral difficulty and academic achievement were explored in 2 samples followed from 6th through 8th grade. The first sample comprised 280 students entering an economically disadvantaged urban middle school and the second comprised 318 students entering an affluent suburban middle school. Among disadvantaged youth, emotional indices were concurrently associated with poorer achievement while prospective associations between substance use and achievement were evident. For privileged adolescents, only a significant concurrent relationship emerged between social anxiety and achievement, although nonsignificant trends in the data suggest other, albeit weak, associations. The findings are discussed in terms of similarities and differences in these temporal associations across 2 samples representing extremes of the socioeconomic continuum. PMID:23129975

GROMACS 4:  Algorithms for Highly Efficient, Load-Balanced, and Scalable Molecular Simulation.

PubMed

Hess, Berk; Kutzner, Carsten; van der Spoel, David; Lindahl, Erik

2008-03-01

Molecular simulation is an extremely useful, but computationally very expensive tool for studies of chemical and biomolecular systems. Here, we present a new implementation of our molecular simulation toolkit GROMACS which now both achieves extremely high performance on single processors from algorithmic optimizations and hand-coded routines and simultaneously scales very well on parallel machines. The code encompasses a minimal-communication domain decomposition algorithm, full dynamic load balancing, a state-of-the-art parallel constraint solver, and efficient virtual site algorithms that allow removal of hydrogen atom degrees of freedom to enable integration time steps up to 5 fs for atomistic simulations also in parallel. To improve the scaling properties of the common particle mesh Ewald electrostatics algorithms, we have in addition used a Multiple-Program, Multiple-Data approach, with separate node domains responsible for direct and reciprocal space interactions. Not only does this combination of algorithms enable extremely long simulations of large systems but also it provides that simulation performance on quite modest numbers of standard cluster nodes.

Phase control of attosecond pulses in a train

NASA Astrophysics Data System (ADS)

Guo, Chen; Harth, Anne; Carlström, Stefanos; Cheng, Yu-Chen; Mikaelsson, Sara; Mårsell, Erik; Heyl, Christoph; Miranda, Miguel; Gisselbrecht, Mathieu; Gaarde, Mette B.; Schafer, Kenneth J.; Mikkelsen, Anders; Mauritsson, Johan; Arnold, Cord L.; L'Huillier, Anne

2018-02-01

Ultrafast processes in matter can be captured and even controlled by using sequences of few-cycle optical pulses, which need to be well characterized, both in amplitude and phase. The same degree of control has not yet been achieved for few-cycle extreme ultraviolet pulses generated by high-order harmonic generation (HHG) in gases, with duration in the attosecond range. Here, we show that by varying the spectral phase and carrier-envelope phase (CEP) of a high-repetition rate laser, using dispersion in glass, we achieve a high degree of control of the relative phase and CEP between consecutive attosecond pulses. The experimental results are supported by a detailed theoretical analysis based upon the semi-classical three-step model for HHG.

Effectiveness of community psychosocial and pharmacological treatments for alcohol use disorder: A national observational cohort study in England.

PubMed

Peacock, Amy; Eastwood, Brian; Jones, Andrew; Millar, Tim; Horgan, Patrick; Knight, Jonathan; Randhawa, Kulvir; White, Martin; Marsden, John

2018-05-01

This was a national English observational cohort study using administrative data to estimate the effectiveness of community pharmacological and psychosocial treatment for alcohol use disorder (AUD). All adults commencing AUD treatment in the community reported to the National Drug Treatment Monitoring System (April 1 2014-March 31 2015; N = 52,499). Past 28-day admission drinking pattern included drinks per drinking day (DDD): 0 ('Abstinent'), 1-15 ('Low-High'), 16-30 ('High-Extreme') and over 30 DDD ('Extreme'). The primary outcome was successful completion of treatment within 12 months of commencement with no re-presentation (SCNR) in the subsequent six months, analysed by multi-level, mixed effects, multivariable logistic regression. The majority reported DDD in the 'Low-High' (n = 17,698, 34%) and 'High-Extreme' (n = 21,383, 41%) range. Smaller proportions were categorised 'Extreme' (n = 7759, 15%) and 'Abstinent' (n = 5661, 11%). Three-fifths (58%) achieved SCNR. Predictors of SCNR were older age, black/minority ethnic group, employment, criminal justice system referral, and longer treatment exposure. Predictors of negative outcome were AUD treatment history, lower socio-economic status, housing problems, and 'Extreme' drinking at admission. In addition to psychosocial interventions, pharmacological interventions and recovery support increased the likelihood of SCNR. Pharmacological treatment was only beneficial for the 'Low-High' groups with recovery support. Over half of all patients admitted for community AUD treatment in England are reported to successfully complete treatment within 12 months and are not re-admitted for further treatment in the following 6 months. Study findings underscore efforts to tailor AUD treatment to the severity of alcohol consumption and using recovery support. Copyright © 2018 Elsevier B.V. All rights reserved.

Broadband dynamic phase matching of high-order harmonic generation by a high-peak-power soliton pump field in a gas-filled hollow photonic-crystal fiber.

PubMed

Serebryannikov, Evgenii E; von der Linde, Dietrich; Zheltikov, Aleksei M

2008-05-01

Hollow-core photonic-crystal fibers are shown to enable dynamically phase-matched high-order harmonic generation by a gigawatt soliton pump field. With a careful design of the waveguide structure and an appropriate choice of input-pulse and gas parameters, a remarkably broadband phase matching can be achieved for a soliton pump field and a large group of optical harmonics in the soft-x-ray-extreme-ultraviolet spectral range.

Inferring the anthropogenic contribution to local temperature extremes

DOE PAGES

Stone, Dáithí A.; Paciorek, Christopher J.; Prabhat, .; ...

2013-03-19

Here, in PNAS, Hansen et al. document an observed planet-wide increase in the frequency of extremely hot months and a decrease in the frequency of extremely cold months, consistent with earlier studies. This analysis is achieved through aggregation of gridded monthly temperature measurements from all over the planet. Such aggregation is advantageous in achieving statistical sampling power; however, it sacrifices regional specificity. Lastly, in that light, we find the conclusion of Hansen et al. that “the extreme summer climate anomalies in Texas in 2011, in Moscow in 2010, and in France in 2003 almost certainly would not have occurred inmore » the absence of global warming” to be unsubstantiated by their analysis.« less

Inferring the anthropogenic contribution to local temperature extremes

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

Stone, Dáithí A.; Paciorek, Christopher J.; Prabhat, .

Here, in PNAS, Hansen et al. document an observed planet-wide increase in the frequency of extremely hot months and a decrease in the frequency of extremely cold months, consistent with earlier studies. This analysis is achieved through aggregation of gridded monthly temperature measurements from all over the planet. Such aggregation is advantageous in achieving statistical sampling power; however, it sacrifices regional specificity. Lastly, in that light, we find the conclusion of Hansen et al. that “the extreme summer climate anomalies in Texas in 2011, in Moscow in 2010, and in France in 2003 almost certainly would not have occurred inmore » the absence of global warming” to be unsubstantiated by their analysis.« less

Rad-Tolerant, Thermally Stable, High-Speed Fiber-Optic Network for Harsh Environments

NASA Technical Reports Server (NTRS)

Leftwich, Matt; Hull, Tony; Leary, Michael; Leftwich, Marcus

2013-01-01

Future NASA destinations will be challenging to get to, have extreme environmental conditions, and may present difficulty in retrieving a spacecraft or its data. Space Photonics is developing a radiation-tolerant (rad-tolerant), high-speed, multi-channel fiber-optic transceiver, associated reconfigurable intelligent node communications architecture, and supporting hardware for intravehicular and ground-based optical networking applications. Data rates approaching 3.2 Gbps per channel will be achieved.

A Cost-Benefit Analysis for Per-Student Expenditures and Academic Achievement

ERIC Educational Resources Information Center

Womack, Sid T.; Roberts, Kerry; Bell, C. David; Womack, Karen

2015-01-01

Cost-benefit correlations have been subject to "selective sampling" in the media. Usually extremes of data from a very few high-funding and low-funding states are cited in the media to construct the case that there is no relationship between economic inputs and academic outputs. This study, using average per-pupil expenditures and ACT…

How Much Hope Is Enough? Levels of Hope and Students' Psychological and School Functioning

ERIC Educational Resources Information Center

Marques, Susana C.; Lopez, Shane J.; Fontaine, Anne Marie; Coimbra, Susana; Mitchell, Joanna

2015-01-01

This study investigated the characteristics of students who report extremely high levels of hope. A sample of 682 students (ages 11-17) completed measures of hope, school engagement, life satisfaction, self-worth, and mental health. Academic achievement was obtained from students' school records. Based on their hope scores, students were divided…

High-efficiency cavity-dumped micro-chip Yb:YAG laser

NASA Astrophysics Data System (ADS)

Nishio, M.; Maruko, A.; Inoue, M.; Takama, M.; Matsubara, S.; Okunishi, H.; Kato, K.; Kyomoto, K.; Yoshida, T.; Shimabayashi, K.; Morioka, M.; Inayoshi, S.; Yamagata, S.; Kawato, S.

2014-09-01

High-efficiency cavity-dumped ytterbium-doped yttrium aluminum garnet (Yb:YAG) laser was developed. Although the high quantum efficiency of ytterbium-doped laser materials is appropriate for high-efficiency laser oscillation, the efficiency is decreased by their quasi-three/four laser natures. High gain operation by high intensity pumping is suitable for high efficiency oscillation on the quasi-three/four lasers without extremely low temperature cooling. In our group, highest efficiency oscillations for continuous wave, nanosecond to picosecond pulse lasers were achieved at room temperature by the high gain operation in which pump intensities were beyond 100 kW/cm2.

Extremely Low Operating Current Resistive Memory Based on Exfoliated 2D Perovskite Single Crystals for Neuromorphic Computing.

PubMed

Tian, He; Zhao, Lianfeng; Wang, Xuefeng; Yeh, Yao-Wen; Yao, Nan; Rand, Barry P; Ren, Tian-Ling

2017-12-26

Extremely low energy consumption neuromorphic computing is required to achieve massively parallel information processing on par with the human brain. To achieve this goal, resistive memories based on materials with ionic transport and extremely low operating current are required. Extremely low operating current allows for low power operation by minimizing the program, erase, and read currents. However, materials currently used in resistive memories, such as defective HfO x , AlO x , TaO x , etc., cannot suppress electronic transport (i.e., leakage current) while allowing good ionic transport. Here, we show that 2D Ruddlesden-Popper phase hybrid lead bromide perovskite single crystals are promising materials for low operating current nanodevice applications because of their mixed electronic and ionic transport and ease of fabrication. Ionic transport in the exfoliated 2D perovskite layer is evident via the migration of bromide ions. Filaments with a diameter of approximately 20 nm are visualized, and resistive memories with extremely low program current down to 10 pA are achieved, a value at least 1 order of magnitude lower than conventional materials. The ionic migration and diffusion as an artificial synapse is realized in the 2D layered perovskites at the pA level, which can enable extremely low energy neuromorphic computing.

Microchannel plate EUV detectors for the Extreme Ultraviolet Explorer

NASA Technical Reports Server (NTRS)

Siegmund, O. H. W.; Malina, R. F.; Coburn, K.; Werthimer, D.

1984-01-01

The design and operating characteristics of the prototype imaging microchannel plate (MCP) detector for the Extreme Ultraviolet Explorer (EUVE) Satellite are discussed. It is shown that this detector has achieved high position resolution performance (greater than 512 x 512 pixels) and has low (less than one percent) image distortion. In addition, the channel plate scheme used has tight pulse height distributions (less than 40 percent FWHM) for UV radiation and displays low (less than 0.2 cnt/sq cm-s) dark background counting rates. Work that has been done on EUV filters in relation to the envisaged filter and photocathode complement is also described.

Charged particle dynamics in multiple colliding electromagnetic waves. Survey of random walk, Lévy flights, limit circles, attractors and structurally determinate patterns

NASA Astrophysics Data System (ADS)

Bulanov, S. V.; Esirkepov, T. Zh.; Koga, J. K.; Bulanov, S. S.; Gong, Z.; Yan, X. Q.; Kando, M.

2017-04-01

The multiple colliding laser pulse concept formulated by Bulanov et al. (Phys. Rev. Lett., vol. 104, 2010b, 220404) is beneficial for achieving an extremely high amplitude of coherent electromagnetic field. Since the topology of electric and magnetic fields of multiple colliding laser pulses oscillating in time is far from trivial and the radiation friction effects are significant in the high field limit, the dynamics of charged particles interacting with the multiple colliding laser pulses demonstrates remarkable features corresponding to random walk trajectories, limit circles, attractors, regular patterns and Lévy flights. Under extremely high intensity conditions the nonlinear dissipation mechanism stabilizes the particle motion resulting in the charged particle trajectory being located within narrow regions and in the occurrence of a new class of regular patterns made by the particle ensembles.

Charged particle dynamics in multiple colliding electromagnetic waves. Survey of random walk, Lévy flights, limit circles, attractors and structurally determinate patterns

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

Bulanov, S. V.; Esirkepov, T. Zh.; Koga, J. K.

The multiple colliding laser pulse concept formulated by Bulanovet al.(Phys. Rev. Lett., vol. 104, 2010b, 220404) is beneficial for achieving an extremely high amplitude of coherent electromagnetic field. Since the topology of electric and magnetic fields of multiple colliding laser pulses oscillating in time is far from trivial and the radiation friction effects are significant in the high field limit, the dynamics of charged particles interacting with the multiple colliding laser pulses demonstrates remarkable features corresponding to random walk trajectories, limit circles, attractors, regular patterns and Lévy flights. Lastly, under extremely high intensity conditions the nonlinear dissipation mechanism stabilizes the particle motionmore » resulting in the charged particle trajectory being located within narrow regions and in the occurrence of a new class of regular patterns made by the particle ensembles.« less

Charged particle dynamics in multiple colliding electromagnetic waves. Survey of random walk, Lévy flights, limit circles, attractors and structurally determinate patterns

DOE PAGES

Bulanov, S. V.; Esirkepov, T. Zh.; Koga, J. K.; ...

2017-03-09

The multiple colliding laser pulse concept formulated by Bulanovet al.(Phys. Rev. Lett., vol. 104, 2010b, 220404) is beneficial for achieving an extremely high amplitude of coherent electromagnetic field. Since the topology of electric and magnetic fields of multiple colliding laser pulses oscillating in time is far from trivial and the radiation friction effects are significant in the high field limit, the dynamics of charged particles interacting with the multiple colliding laser pulses demonstrates remarkable features corresponding to random walk trajectories, limit circles, attractors, regular patterns and Lévy flights. Lastly, under extremely high intensity conditions the nonlinear dissipation mechanism stabilizes the particle motionmore » resulting in the charged particle trajectory being located within narrow regions and in the occurrence of a new class of regular patterns made by the particle ensembles.« less

Beyond Extreme Ultra Violet (BEUV) Radiation from Spherically symmetrical High-Z plasmas

NASA Astrophysics Data System (ADS)

Yoshida, Kensuke; Fujioka, Shinsuke; Higashiguchi, Takeshi; Ugomori, Teruyuki; Tanaka, Nozomi; Kawasaki, Masato; Suzuki, Yuhei; Suzuki, Chihiro; Tomita, Kentaro; Hirose, Ryouichi; Eshima, Takeo; Ohashi, Hayato; Nishikino, Masaharu; Scally, Enda; Nshimura, Hiroaki; Azechi, Hiroshi; O'Sullivan, Gerard

2016-03-01

Photo-lithography is a key technology for volume manufacture of high performance and compact semiconductor devices. Smaller and more complex structures can be fabricated by using shorter wavelength light in the photolithography. One of the most critical issues in development of the next generation photo-lithography is to increase energy conversion efficiency (CE) from laser to shorter wavelength light. Experimental database of beyond extreme ultraviolet (BEUV) radiation was obtained by using spherically symmetrical high-Z plasmas generated with spherically allocated laser beams. Absolute energy and spectra of BEUV light emitted from Tb, Gd, and Mo plasmas were measured with a absolutely calibrated BEUV calorimeter and a transmission grating spectrometer. 1.0 x 1012 W/cm2 is the optimal laser intensity to produced efficient BEUV light source plasmas with Tb and Gd targets. Maximum CE is achieved at 0.8% that is two times higher than the published CEs obtained with planar targets.

Feasibility of High-Repetition, Task-Specific Training for Individuals With Upper-Extremity Paresis

PubMed Central

Waddell, Kimberly J.; Birkenmeier, Rebecca L.; Moore, Jennifer L.; Hornby, T. George

2014-01-01

OBJECTIVE. We investigated the feasibility of delivering an individualized, progressive, high-repetition upper-extremity (UE) task-specific training protocol for people with stroke in the inpatient rehabilitation setting. METHOD. Fifteen patients with UE paresis participated in this study. Task-specific UE training was scheduled for 60 min/day, 4 days/wk, during occupational therapy for the duration of a participant’s inpatient stay. During each session, participants were challenged to complete ≥300 repetitions of various tasks. RESULTS. Participants averaged 289 repetitions/session, spending 47 of 60 min in active training. Participants improved on impairment and activity level outcome measures. CONCLUSION. People with stroke in an inpatient setting can achieve hundreds of repetitions of task-specific training in 1-hr sessions. As expected, all participants improved on functional outcome measures. Future studies are needed to determine whether this high-repetition training program results in better outcomes than current UE interventions. PMID:25005508

Trends in Gender Differences in Academic Achievement from 1960 to 1994: An Analysis of Differences in Mean, Variance, and Extreme Scores.

ERIC Educational Resources Information Center

Nowell, Amy; Hedges, Larry V.

1998-01-01

Uses evidence from seven surveys of the U.S. 12th-grade population and the National Assessment of Educational Progress to show that gender differences in mean and variance in academic achievement are small from 1960 to 1994 but that differences in extreme scores are often substantial. (SLD)

Extremophiles: from abyssal to terrestrial ecosystems and possibly beyond

NASA Astrophysics Data System (ADS)

Canganella, Francesco; Wiegel, Juergen

2011-04-01

The anthropocentric term "extremophile" was introduced more than 30 years ago to describe any organism capable of living and growing under extreme conditions—i.e., particularly hostile to human and to the majority of the known microorganisms as far as temperature, pH, and salinity parameters are concerned. With the further development of studies on microbial ecology and taxonomy, more "extreme" environments were found and more extremophiles were described. Today, many different extremophiles have been isolated from habitats characterized by hydrostatic pressure, aridity, radiations, elevated temperatures, extreme pH values, high salt concentrations, and high solvent/metal concentrations, and it is well documented that these microorganisms are capable of thriving under extreme conditions better than any other organism living on Earth. Extremophiles have also been investigated as far as the search for life in other planets is concerned and even to evaluate the hypothesis that life on Earth came originally from space. Extremophiles are interesting for basic and applied sciences. Particularly fascinating are their structural and physiological features allowing them to stand extremely selective environmental conditions. These properties are often due to specific biomolecules (DNA, lipids, enzymes, osmolites, etc.) that have been studied for years as novel sources for biotechnological applications. In some cases (DNA polymerase, thermostable enzymes), the search was successful and the final application was achieved, but certainly further exploitations are next to come.

Closed Loop, DM Diversity-based, Wavefront Correction Algorithm for High Contrast Imaging Systems

NASA Technical Reports Server (NTRS)

Give'on, Amir; Belikov, Ruslan; Shaklan, Stuart; Kasdin, Jeremy

2007-01-01

High contrast imaging from space relies on coronagraphs to limit diffraction and a wavefront control systems to compensate for imperfections in both the telescope optics and the coronagraph. The extreme contrast required (up to 10(exp -10) for terrestrial planets) puts severe requirements on the wavefront control system, as the achievable contrast is limited by the quality of the wavefront. This paper presents a general closed loop correction algorithm for high contrast imaging coronagraphs by minimizing the energy in a predefined region in the image where terrestrial planets could be found. The estimation part of the algorithm reconstructs the complex field in the image plane using phase diversity caused by the deformable mirror. This method has been shown to achieve faster and better correction than classical speckle nulling.

Performance of Improved High-Order Filter Schemes for Turbulent Flows with Shocks

NASA Technical Reports Server (NTRS)

Kotov, Dmitry Vladimirovich; Yee, Helen M C.

2013-01-01

The performance of the filter scheme with improved dissipation control ? has been demonstrated for different flow types. The scheme with local ? is shown to obtain more accurate results than its counterparts with global or constant ?. At the same time no additional tuning is needed to achieve high accuracy of the method when using the local ? technique. However, further improvement of the method might be needed for even more complex and/or extreme flows.

An Inner-City School Mentor: A Narrative Inquiry of the Life Experiences of "Daddy"

ERIC Educational Resources Information Center

Li, Xin; Lal, Dhyan

2006-01-01

A two-year ethnographic observation of an inner-city high school in Los Angeles, USA, indicated that the principal, who was extremely dedicated to at-risk students and possessed a unique style of mentoring, played a major role in students academic achievement. We--the principal and the researcher who observed the school--inquired about the…

The Effect of Learning Style Awareness, Strategies, and Classroom Type on Grades (Achievement) in High School Algebra II

ERIC Educational Resources Information Center

Adduci, Stacy B.

2017-01-01

Improving the nation's math prowess and preparing the youth to be college or career ready, may need to be solved by a culmination of theories from different perspectives. As the controversial meshing hypothesis contends that teachers should present information according to each students' learning styles; this can be extremely difficult in a…

Robust, nonlinear, high angle-of-attack control design for a supermaneuverable vehicle

NASA Technical Reports Server (NTRS)

Adams, Richard J.

1993-01-01

High angle-of-attack flight control laws are developed for a supermaneuverable fighter aircraft. The methods of dynamic inversion and structured singular value synthesis are combined into an approach which addresses both the nonlinearity and robustness problems of flight at extreme operating conditions. The primary purpose of the dynamic inversion control elements is to linearize the vehicle response across the flight envelope. Structured singular value synthesis is used to design a dynamic controller which provides robust tracking to pilot commands. The resulting control system achieves desired flying qualities and guarantees a large margin of robustness to uncertainties for high angle-of-attack flight conditions. The results of linear simulation and structured singular value stability analysis are presented to demonstrate satisfaction of the design criteria. High fidelity nonlinear simulation results show that the combined dynamics inversion/structured singular value synthesis control law achieves a high level of performance in a realistic environment.

Pseudo-differential CMOS analog front-end circuit for wide-bandwidth optical probe current sensor

NASA Astrophysics Data System (ADS)

Uekura, Takaharu; Oyanagi, Kousuke; Sonehara, Makoto; Sato, Toshiro; Miyaji, Kousuke

2018-04-01

In this paper, we present a pseudo-differential analog front-end (AFE) circuit for a novel optical probe current sensor (OPCS) aimed for high-frequency power electronics. It employs a regulated cascode transimpedance amplifier (RGC-TIA) to achieve a high gain and a large bandwidth without using an extremely high performance operational amplifier. The AFE circuit is designed in a 0.18 µm standard CMOS technology achieving a high transimpedance gain of 120 dB Ω and high cut off frequency of 16 MHz. The measured slew rate is 70 V/µs and the input referred current noise is 1.02 pA/\\sqrt{\\text{Hz}} . The magnetic resolution and bandwidth of OPCS are estimated to be 1.29 mTrms and 16 MHz, respectively; the bandwidth is higher than that of the reported Hall effect current sensor.

Achieving a 100% Renewable Grid: Operating Electric Power Systems with Extremely High Levels of Variable Renewable Energy

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

Kroposki, Benjamin; Johnson, Brian; Zhang, Yingchen

What does it mean to achieve a 100% renewable grid? Several countries already meet or come close to achieving this goal. Iceland, for example, supplies 100% of its electricity needs with either geothermal or hydropower. Other countries that have electric grids with high fractions of renewables based on hydropower include Norway (97%), Costa Rica (93%), Brazil (76%), and Canada (62%). Hydropower plants have been used for decades to create a relatively inexpensive, renewable form of energy, but these systems are limited by natural rainfall and geographic topology. Around the world, most good sites for large hydropower resources have already beenmore » developed. So how do other areas achieve 100% renewable grids? Variable renewable energy (VRE), such as wind and solar photovoltaic (PV) systems, will be a major contributor, and with the reduction in costs for these technologies during the last five years, large-scale deployments are happening around the world.« less

Isolated limb infusion with fotemustine after dacarbazine chemosensitisation for inoperable loco-regional melanoma recurrence.

PubMed

Bonenkamp, J J; Thompson, J F; de Wilt, J H; Doubrovsky, A; de Faria Lima, R; Kam, P C A

2004-12-01

Isolated limb infusion (ILI) is a simple yet effective alternative to conventional isolated limb perfusion for the treatment of advanced melanoma of the extremities. The study group comprised 13 patients with very advanced limb disease who had failed to achieve a satisfactory response to one or more ILIs with melphalan, and in whom amputation was the only other realistic treatment option. The aim of this study was to evaluate the efficacy and toxicity of ILI with fotemustine after systemic chemosensitisation with dacarbazine (DTIC). Complete remission was achieved in four patients and partial remission in eight patients, with a median response duration of 3 months. Limb salvage was achieved in five of 12 assessable patients (42%). Limb toxicity peaked 9 days after ILI; two patients experienced Wieberdink grade IV (severe) toxicity and four patients had grade V toxicity (requiring early amputation). ILI with fotemustine after DTIC chemosensitisation can be successful when gross limb disease has not been controlled by one or more ILIs with melphalan. However, it cannot be recommended as a routine method of treatment for advanced melanoma of the extremities because of the high incidence of severe limb toxicity.

Hot air vulcanization of rubber profiles

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

Gerlach, J.

1995-07-01

Elastomer profiles are deployed in quantity by the automobile industry as seals and wateproofing in coachwork. The high standards demanded by the industry; improvement in weather prediction, noise reduction, restriction of tolerances, together with powerful demand for EPDM force the rubber processing industry into development, particularly of elastomers. Complex proofing systems must also be achieved with extremely complicated profile forms. All too often such profiles have an extremely large surface together with a low cross-section density. They frequently consist of two or three rubber compounds and are steel reinforced. Sometimes they are flocked and coated with a low friction finish.more » Such high-tech seals require an adjustment of the vulcanization method. The consistent trend in the nineties towards lower quantities of elastomer per sealing unit and the dielectric factor, especially with EPDM, has brought an old fashioned vulcanization method once more to the fore, a method developed over the past years to an extremely high standard, namely the hot-air method. This paper describes various vulcanization and curing methods and their relative merits and disadvantages, the Gerlach hot-air concept, the hot air installation concept, and energy saving and efficiency afforded by this technique. 4 figs.« less

Nanoionic devices: Interface nanoarchitechtonics for physical property tuning and enhancement

NASA Astrophysics Data System (ADS)

Tsuchiya, Takashi; Terabe, Kazuya; Yang, Rui; Aono, Masakazu

2016-11-01

Nanoionic devices have been developed to generate novel functions overcoming limitations of conventional materials synthesis and semiconductor technology. Various physical properties can be tuned and enhanced by local ion transport near the solid/solid interface. Two electronic carrier doping methods can be used to achieve extremely high-density electronic carriers: one is electrostatic carrier doping using an electric double layer (EDL); the other is electrochemical carrier doping using a redox reaction. Atomistic restructuring near the solid/solid interface driven by a DC voltage, namely, interface nanoarchitechtonics, has huge potential. For instance, the use of EDL enables high-density carrier doping in potential superconductors, which can hardly accept chemical doping, in order to achieve room-temperature superconductivity. Optical bandgap and photoluminescence can be controlled for various applications including smart windows and biosensors. In situ tuning of magnetic properties is promising for low-power-consumption spintronics. Synaptic plasticity in the human brain is achieved in neuromorphic devices.

Risky business: human factors in critical care.

PubMed

Laussen, Peter C; Allan, Catherine K; Larovere, Joan M

2011-07-01

Remarkable achievements have occurred in pediatric cardiac critical care over the past two decades. The specialty has become well defined and extremely resource intense. A great deal of focus has been centered on optimizing patient outcomes, particularly mortality and early morbidity, and this has been achieved through a focused and multidisciplinary approach to management. Delivering high-quality and safe care is our goal, and during the Risky Business symposium and simulation sessions at the Eighth International Conference of the Pediatric Cardiac Intensive Care Society in Miami, December 2010, human factors, systems analysis, team training, and lessons learned from malpractice claims were presented.

Development and Reliability Evaluation of the Movement Rating Instrument for Virtual Reality Video Game Play.

PubMed

Levac, Danielle; Nawrotek, Joanna; Deschenes, Emilie; Giguere, Tia; Serafin, Julie; Bilodeau, Martin; Sveistrup, Heidi

2016-06-01

Virtual reality active video games are increasingly popular physical therapy interventions for children with cerebral palsy. However, physical therapists require educational resources to support decision making about game selection to match individual patient goals. Quantifying the movements elicited during virtual reality active video game play can inform individualized game selection in pediatric rehabilitation. The objectives of this study were to develop and evaluate the feasibility and reliability of the Movement Rating Instrument for Virtual Reality Game Play (MRI-VRGP). Item generation occurred through an iterative process of literature review and sample videotape viewing. The MRI-VRGP includes 25 items quantifying upper extremity, lower extremity, and total body movements. A total of 176 videotaped 90-second game play sessions involving 7 typically developing children and 4 children with cerebral palsy were rated by 3 raters trained in MRI-VRGP use. Children played 8 games on 2 virtual reality and active video game systems. Intraclass correlation coefficients (ICCs) determined intra-rater and interrater reliability. Excellent intrarater reliability was evidenced by ICCs of >0.75 for 17 of the 25 items across the 3 raters. Interrater reliability estimates were less precise. Excellent interrater reliability was achieved for far reach upper extremity movements (ICC=0.92 [for right and ICC=0.90 for left) and for squat (ICC=0.80) and jump items (ICC=0.99), with 9 items achieving ICCs of >0.70, 12 items achieving ICCs of between 0.40 and 0.70, and 4 items achieving poor reliability (close-reach upper extremity-ICC=0.14 for right and ICC=0.07 for left) and single-leg stance (ICC=0.55 for right and ICC=0.27 for left). Poor video quality, differing item interpretations between raters, and difficulty quantifying the high-speed movements involved in game play affected reliability. With item definition clarification and further psychometric property evaluation, the MRI-VRGP could inform the content of educational resources for therapists by ranking games according to frequency and type of elicited body movements.

Development and Reliability Evaluation of the Movement Rating Instrument for Virtual Reality Video Game Play

PubMed Central

Nawrotek, Joanna; Deschenes, Emilie; Giguere, Tia; Serafin, Julie; Bilodeau, Martin; Sveistrup, Heidi

2016-01-01

Background Virtual reality active video games are increasingly popular physical therapy interventions for children with cerebral palsy. However, physical therapists require educational resources to support decision making about game selection to match individual patient goals. Quantifying the movements elicited during virtual reality active video game play can inform individualized game selection in pediatric rehabilitation. Objective The objectives of this study were to develop and evaluate the feasibility and reliability of the Movement Rating Instrument for Virtual Reality Game Play (MRI-VRGP). Methods Item generation occurred through an iterative process of literature review and sample videotape viewing. The MRI-VRGP includes 25 items quantifying upper extremity, lower extremity, and total body movements. A total of 176 videotaped 90-second game play sessions involving 7 typically developing children and 4 children with cerebral palsy were rated by 3 raters trained in MRI-VRGP use. Children played 8 games on 2 virtual reality and active video game systems. Intraclass correlation coefficients (ICCs) determined intra-rater and interrater reliability. Results Excellent intrarater reliability was evidenced by ICCs of >0.75 for 17 of the 25 items across the 3 raters. Interrater reliability estimates were less precise. Excellent interrater reliability was achieved for far reach upper extremity movements (ICC=0.92 [for right and ICC=0.90 for left) and for squat (ICC=0.80) and jump items (ICC=0.99), with 9 items achieving ICCs of >0.70, 12 items achieving ICCs of between 0.40 and 0.70, and 4 items achieving poor reliability (close-reach upper extremity-ICC=0.14 for right and ICC=0.07 for left) and single-leg stance (ICC=0.55 for right and ICC=0.27 for left). Conclusions Poor video quality, differing item interpretations between raters, and difficulty quantifying the high-speed movements involved in game play affected reliability. With item definition clarification and further psychometric property evaluation, the MRI-VRGP could inform the content of educational resources for therapists by ranking games according to frequency and type of elicited body movements. PMID:27251029

Nanoelectromechanical systems: Nanodevice motion at microwave frequencies

NASA Astrophysics Data System (ADS)

Henry Huang, Xue Ming; Zorman, Christian A.; Mehregany, Mehran; Roukes, Michael L.

2003-01-01

It has been almost forgotten that the first computers envisaged by Charles Babbage in the early 1800s were mechanical and not electronic, but the development of high-frequency nanoelectromechanical systems is now promising a range of new applications, including sensitive mechanical charge detectors and mechanical devices for high-frequency signal processing, biological imaging and quantum measurement. Here we describe the construction of nanodevices that will operate with fundamental frequencies in the previously inaccessible microwave range (greater than 1 gigahertz). This achievement represents a significant advance in the quest for extremely high-frequency nanoelectromechanical systems.

Fabrication of highly efficient ZnO nanoscintillators

NASA Astrophysics Data System (ADS)

Procházková, Lenka; Gbur, Tomáš; Čuba, Václav; Jarý, Vítězslav; Nikl, Martin

2015-09-01

Photo-induced synthesis of high-efficiency ultrafast nanoparticle scintillators of ZnO was demonstrated. Controlled doping with Ga(III) and La(III) ions together with the optimized method of ZnO synthesis and subsequent two-step annealing in air and under reducing atmosphere allow to achieve very high intensity of UV exciton luminescence, up to 750% of BGO intensity magnitude. Fabricated nanoparticles feature extremely short sub-nanosecond photoluminescence decay times. Temperature dependence of the photoluminescence spectrum within 8-340 K range was investigated and shows the absence of visible defect-related emission within all temperature intervals.

A Novel Extreme Learning Control Framework of Unmanned Surface Vehicles.

PubMed

Wang, Ning; Sun, Jing-Chao; Er, Meng Joo; Liu, Yan-Cheng

2016-05-01

In this paper, an extreme learning control (ELC) framework using the single-hidden-layer feedforward network (SLFN) with random hidden nodes for tracking an unmanned surface vehicle suffering from unknown dynamics and external disturbances is proposed. By combining tracking errors with derivatives, an error surface and transformed states are defined to encapsulate unknown dynamics and disturbances into a lumped vector field of transformed states. The lumped nonlinearity is further identified accurately by an extreme-learning-machine-based SLFN approximator which does not require a priori system knowledge nor tuning input weights. Only output weights of the SLFN need to be updated by adaptive projection-based laws derived from the Lyapunov approach. Moreover, an error compensator is incorporated to suppress approximation residuals, and thereby contributing to the robustness and global asymptotic stability of the closed-loop ELC system. Simulation studies and comprehensive comparisons demonstrate that the ELC framework achieves high accuracy in both tracking and approximation.

A Neuroscience Approach to Optimizing Brain Resources for Human Performance in Extreme Environments

PubMed Central

Paulus, Martin P.; Potterat, Eric G.; Taylor, Marcus K.; Van Orden, Karl F.; Bauman, James; Momen, Nausheen; Padilla, Genieleah A.; Swain, Judith L.

2009-01-01

Extreme environments requiring optimal cognitive and behavioral performance occur in a wide variety of situations ranging from complex combat operations to elite athletic competitions. Although a large literature characterizes psychological and other aspects of individual differences in performances in extreme environments, virtually nothing is known about the underlying neural basis for these differences. This review summarizes the cognitive, emotional, and behavioral consequences of exposure to extreme environments, discusses predictors of performance, and builds a case for the use of neuroscience approaches to quantify and understand optimal cognitive and behavioral performance. Extreme environments are defined as an external context that exposes individuals to demanding psychological and/or physical conditions, and which may have profound effects on cognitive and behavioral performance. Examples of these types of environments include combat situations, Olympic-level competition, and expeditions in extreme cold, at high altitudes, or in space. Optimal performance is defined as the degree to which individuals achieve a desired outcome when completing goal-oriented tasks. It is hypothesized that individual variability with respect to optimal performance in extreme environments depends on a well “contextualized” internal body state that is associated with an appropriate potential to act. This hypothesis can be translated into an experimental approach that may be useful for quantifying the degree to which individuals are particularly suited to performing optimally in demanding environments. PMID:19447132

Extremely Low Roll-Off and High Efficiency Achieved by Strategic Exciton Management in Organic Light-Emitting Diodes with Simple Ultrathin Emitting Layer Structure.

PubMed

Zhang, Tianmu; Shi, Changsheng; Zhao, Chenyang; Wu, Zhongbin; Chen, Jiangshan; Xie, Zhiyuan; Ma, Dongge

2018-03-07

Phosphorescent organic light-emitting diodes (OLEDs) possess the property of high efficiency but have serious efficiency roll-off at high luminance. Herein, we manufactured high-efficiency phosphorescent OLEDs with extremely low roll-off by effectively locating the ultrathin emitting layer (UEML) away from the high-concentration exciton formation region. The strategic exciton management in this simple UEML architecture greatly suppressed the exciton annihilation due to the expansion of the exciton diffusion region; thus, this efficiency roll-off at high luminance was significantly improved. The resulting green phosphorescent OLEDs exhibited the maximum external quantum efficiency of 25.5%, current efficiency of 98.0 cd A -1 , and power efficiency of 85.4 lm W -1 and still had 25.1%, 94.9 cd A -1 , and 55.5 lm W -1 at 5000 cd m -2 luminance, and retained 24.3%, 92.7 cd A -1 , and 49.3 lm W -1 at 10 000 cd m -2 luminance, respectively. Compared with the usual structures, the improvement demonstrated in this work displays potential value in applications.

Transparent air filter for high-efficiency PM2.5 capture.

PubMed

Liu, Chong; Hsu, Po-Chun; Lee, Hyun-Wook; Ye, Meng; Zheng, Guangyuan; Liu, Nian; Li, Weiyang; Cui, Yi

2015-02-16

Particulate matter (PM) pollution has raised serious concerns for public health. Although outdoor individual protection could be achieved by facial masks, indoor air usually relies on expensive and energy-intensive air-filtering devices. Here, we introduce a transparent air filter for indoor air protection through windows that uses natural passive ventilation to effectively protect the indoor air quality. By controlling the surface chemistry to enable strong PM adhesion and also the microstructure of the air filters to increase the capture possibilities, we achieve transparent, high air flow and highly effective air filters of ~90% transparency with >95.00% removal of PM2.5 under extreme hazardous air-quality conditions (PM2.5 mass concentration >250 μg m(-3)). A field test in Beijing shows that the polyacrylonitrile transparent air filter has the best PM2.5 removal efficiency of 98.69% at high transmittance of ~77% during haze occurrence.

Transparent air filter for high-efficiency PM2.5 capture

NASA Astrophysics Data System (ADS)

Liu, Chong; Hsu, Po-Chun; Lee, Hyun-Wook; Ye, Meng; Zheng, Guangyuan; Liu, Nian; Li, Weiyang; Cui, Yi

2015-02-01

Particulate matter (PM) pollution has raised serious concerns for public health. Although outdoor individual protection could be achieved by facial masks, indoor air usually relies on expensive and energy-intensive air-filtering devices. Here, we introduce a transparent air filter for indoor air protection through windows that uses natural passive ventilation to effectively protect the indoor air quality. By controlling the surface chemistry to enable strong PM adhesion and also the microstructure of the air filters to increase the capture possibilities, we achieve transparent, high air flow and highly effective air filters of ~90% transparency with >95.00% removal of PM2.5 under extreme hazardous air-quality conditions (PM2.5 mass concentration >250 μg m-3). A field test in Beijing shows that the polyacrylonitrile transparent air filter has the best PM2.5 removal efficiency of 98.69% at high transmittance of ~77% during haze occurrence.

Latest performance of ArF immersion scanner NSR-S630D for high-volume manufacturing for 7nm node

NASA Astrophysics Data System (ADS)

Funatsu, Takayuki; Uehara, Yusaku; Hikida, Yujiro; Hayakawa, Akira; Ishiyama, Satoshi; Hirayama, Toru; Kono, Hirotaka; Shirata, Yosuke; Shibazaki, Yuichi

2015-03-01

In order to achieve stable operation in cutting-edge semiconductor manufacturing, Nikon has developed NSR-S630D with extremely accurate overlay while maintaining throughput in various conditions resembling a real production environment. In addition, NSR-S630D has been equipped with enhanced capabilities to maintain long-term overlay stability and user interface improvement all due to our newly developed application software platform. In this paper, we describe the most recent S630D performance in various conditions similar to real productions. In a production environment, superior overlay accuracy with high dose conditions and high throughput are often required; therefore, we have performed several experiments with high dose conditions to demonstrate NSR's thermal aberration capabilities in order to achieve world class overlay performance. Furthermore, we will introduce our new software that enables long term overlay performance.

Wearable, wireless gas sensors using highly stretchable and transparent structures of nanowires and graphene

NASA Astrophysics Data System (ADS)

Park, Jihun; Kim, Joohee; Kim, Kukjoo; Kim, So-Yun; Cheong, Woon Hyung; Park, Kyeongmin; Song, Joo Hyeb; Namgoong, Gyeongho; Kim, Jae Joon; Heo, Jaeyeong; Bien, Franklin; Park, Jang-Ung

2016-05-01

Herein, we report the fabrication of a highly stretchable, transparent gas sensor based on silver nanowire-graphene hybrid nanostructures. Due to its superb mechanical and optical characteristics, the fabricated sensor demonstrates outstanding and stable performances even under extreme mechanical deformation (stable until 20% of strain). The integration of a Bluetooth system or an inductive antenna enables the wireless operation of the sensor. In addition, the mechanical robustness of the materials allows the device to be transferred onto various nonplanar substrates, including a watch, a bicycle light, and the leaves of live plants, thereby achieving next-generation sensing electronics for the `Internet of Things' area.Herein, we report the fabrication of a highly stretchable, transparent gas sensor based on silver nanowire-graphene hybrid nanostructures. Due to its superb mechanical and optical characteristics, the fabricated sensor demonstrates outstanding and stable performances even under extreme mechanical deformation (stable until 20% of strain). The integration of a Bluetooth system or an inductive antenna enables the wireless operation of the sensor. In addition, the mechanical robustness of the materials allows the device to be transferred onto various nonplanar substrates, including a watch, a bicycle light, and the leaves of live plants, thereby achieving next-generation sensing electronics for the `Internet of Things' area. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01468b

Academic Self-Concept, Achievement Goals, and Achievement: Is Their Relation the Same for Academic Achievers and Underachievers?

ERIC Educational Resources Information Center

Preckel, Franzis; Brunner, Martin

2015-01-01

This longitudinal study investigated the contribution of achievement goals and academic self-concept for the prediction of unexpected academic achievement (i.e., achievement that is higher or lower than expected with respect to students' cognitive ability) in general and when comparing groups of extreme over- and underachievers. Our sample…

Water storage equity and safety assurance policy to mitigate potential 'dual-extreme cumulative threats' in agricultural catchments

NASA Astrophysics Data System (ADS)

Pisaniello, John D.; Tingey-Holyoak, Joanne L.

2017-02-01

Farm dams that are not managed properly at the individual level can create water storage equity and safety threats to downstream communities and the environment that aggregate at the catchment level: a potential 'dual-extreme cumulative' problem. The paper provides indicative evidence and develops understanding of this novel phenomenon and associated policy needs within the Australian setting comprising dual hydrologic extremes of floods and droughts, further exacerbated by climate change. This is achieved through comparative case studies involving surveys of both dam owner perceptions and dam management practices in four States representing a complete range of integrated policy approaches from weak to strong. Survey results find most farmers do not believe dam maintenance is important, will undertake spillway blocking and do not plan for emergencies. These results are supported by physical on-site findings of farmers neglecting dams and blocking or under-designing spillways, in turn storing more water than they are entitled and creating unsafe dams at both the individual and cumulative levels. From detailed cross-case comparative assessment against policy context, it emerges that on-farm perceptions and practices form a range of 'acceptability' of dam management that directly reflects policy strength and integration in each setting. The paper advances the international small dams policy, agricultural water management and hydrology literatures, evidencing the need for effective integrated policy to mitigate dual extreme cumulative threats. Importantly, guidance is provided to jurisdictions internationally with high inter-annual rainfall variation on how best to design integrated policy that can achieve both water storage equity and safety in agricultural catchments.

Cognitive Profiles of Mathematical Problem Solving Learning Disability for Different Definitions of Disability

ERIC Educational Resources Information Center

Tolar, Tammy D.; Fuchs, Lynn; Fletcher, Jack M.; Fuchs, Douglas; Hamlett, Carol L.

2016-01-01

Three cohorts of third-grade students (N = 813) were evaluated on achievement, cognitive abilities, and behavioral attention according to contrasting research traditions in defining math learning disability (LD) status: low achievement versus extremely low achievement and IQ-achievement discrepant versus strictly low-achieving LD. We use methods…

HIV-infected patients receiving lopinavir/ritonavir-based antiretroviral therapy achieve high rates of virologic suppression despite adherence rates less than 95%.

PubMed

Shuter, Jonathan; Sarlo, Julie A; Kanmaz, Tina J; Rode, Richard A; Zingman, Barry S

2007-05-01

The observation that extremely high levels of medication adherence are required to achieve complete virologic suppression is based largely on studies of treatment-experienced patients receiving HIV protease inhibitor (PI)-based therapy without ritonavir boosting. This study aims to define the level of adherence needed to achieve virologic suppression in patients receiving boosted PI-based highly active antiretroviral therapy (HAART) with lopinavir/ritonavir. HIV-infected adults receiving a regimen containing lopinavir/ritonavir were recruited into a prospective, observational study of the relation between adherence to lopinavir/ritonavir and virologic outcomes. Adherence was measured using the Medication Event Monitoring System (MEMS; Aardex, Union City, CA). HIV-1 viral load (VL) was measured at week 24. The final study population contained 64 subjects. Eighty percent had AIDS, 97% received lopinavir/ritonavir before enrollment, and most had more than 7 years of HAART experience. Mean adherence overall was 73%. Eighty percent and 59% achieved a VL <400 copies/mL and a VL <75 copies/mL, respectively. Mean adherence was 75% in those achieving a VL <75 copies/mL. High rates of virologic suppression were observed in all adherence quartiles, including the lowest quartile (range of adherence: 23.5%-53.3%). Moderate levels of adherence can lead to virologic suppression in most patients taking lopinavir/ritonavir-based HAART.

Neutron scattering reveals the dynamic basis of protein adaptation to extreme temperature.

PubMed

Tehei, Moeava; Madern, Dominique; Franzetti, Bruno; Zaccai, Giuseppe

2005-12-09

To explore protein adaptation to extremely high temperatures, two parameters related to macromolecular dynamics, the mean square atomic fluctuation and structural resilience, expressed as a mean force constant, were measured by neutron scattering for hyperthermophilic malate dehydrogenase from Methanococcus jannaschii and a mesophilic homologue, lactate dehydrogenase from Oryctolagus cunniculus (rabbit) muscle. The root mean square fluctuations, defining flexibility, were found to be similar for both enzymes (1.5 A) at their optimal activity temperature. Resilience values, defining structural rigidity, are higher by an order of magnitude for the high temperature-adapted protein (0.15 Newtons/meter for O. cunniculus lactate dehydrogenase and 1.5 Newtons/meter for M. jannaschii malate dehydrogenase). Thermoadaptation appears to have been achieved by evolution through selection of appropriate structural rigidity in order to preserve specific protein structure while allowing the conformational flexibility required for activity.

Extremely high frequency electromagnetic irradiation in combination with antibiotics enhances antibacterial effects on Escherichia coli.

PubMed

Torgomyan, Heghine; Tadevosyan, Hasmik; Trchounian, Armen

2011-03-01

Antibacterial effects of the electromagnetic irradiation (EMI) of 51.8 and 53 GHz frequencies with low intensity (the flux capacity of 0.06 mW/cm(2)) and non-thermal action were investigated upon direct irradiation of E. coli K12. Significant decrease in bacterial growth rate and in the number of viable cells, marked change in H(+) and K(+) transport across membrane were shown. Subsequent addition of kanamycin or ceftriaxone (15 or 0.4 μM, respectively) enhanced the effects of irradiation. This was maximally achieved at the frequency of 53 GHz. These all might reveal membrane as probable target for antibacterial effects. Apparently, the action of EMI on bacteria might lead to changed membrane properties and to antibiotic resistance. The results should improve using extremely high frequency EMI in combination with antibiotics in biotechnology, therapeutic practice, and food industry.

Extremely high efficient nanoreactor with Au@ZnO catalyst for photocatalysis

NASA Astrophysics Data System (ADS)

Su, Chung-Yi; Yang, Tung-Han; Gurylev, Vitaly; Huang, Sheng-Hsin; Wu, Jenn-Ming; Perng, Tsong-Pyng

2015-10-01

We fabricated a photocatalytic Au@ZnO@PC (polycarbonate) nanoreactor composed of monolayered Au nanoparticles chemisorbed on conformal ZnO nanochannel arrays within the PC membrane. A commercial PC membrane was used as the template for deposition of a ZnO shell into the pores by atomic layer deposition (ALD). Thioctic acid (TA) with sufficient steric stabilization was used as a molecular linker for functionalization of Au nanoparticles in a diameter of 10 nm. High coverage of Au nanoparticles anchored on the inner wall of ZnO nanochannels greatly improved the photocatalytic activity for degradation of Rhodamine B. The membrane nanoreactor achieved 63% degradation of Rhodamine B within only 26.88 ms of effective reaction time owing to its superior mass transfer efficiency based on Damköhler number analysis. Mass transfer limitation can be eliminated in the present study due to extremely large surface-to-volume ratio of the membrane nanoreactor.

Extreme sensitivity biosensing platform based on hyperbolic metamaterials

NASA Astrophysics Data System (ADS)

Sreekanth, Kandammathe Valiyaveedu; Alapan, Yunus; Elkabbash, Mohamed; Ilker, Efe; Hinczewski, Michael; Gurkan, Umut A.; de Luca, Antonio; Strangi, Giuseppe

2016-06-01

Optical sensor technology offers significant opportunities in the field of medical research and clinical diagnostics, particularly for the detection of small numbers of molecules in highly diluted solutions. Several methods have been developed for this purpose, including label-free plasmonic biosensors based on metamaterials. However, the detection of lower-molecular-weight (<500 Da) biomolecules in highly diluted solutions is still a challenging issue owing to their lower polarizability. In this context, we have developed a miniaturized plasmonic biosensor platform based on a hyperbolic metamaterial that can support highly confined bulk plasmon guided modes over a broad wavelength range from visible to near infrared. By exciting these modes using a grating-coupling technique, we achieved different extreme sensitivity modes with a maximum of 30,000 nm per refractive index unit (RIU) and a record figure of merit (FOM) of 590. We report the ability of the metamaterial platform to detect ultralow-molecular-weight (244 Da) biomolecules at picomolar concentrations using a standard affinity model streptavidin-biotin.

Extremely efficient flexible organic light-emitting diodes with modified graphene anode

NASA Astrophysics Data System (ADS)

Han, Tae-Hee; Lee, Youngbin; Choi, Mi-Ri; Woo, Seong-Hoon; Bae, Sang-Hoon; Hong, Byung Hee; Ahn, Jong-Hyun; Lee, Tae-Woo

2012-02-01

Although graphene films have a strong potential to replace indium tin oxide anodes in organic light-emitting diodes (OLEDs), to date, the luminous efficiency of OLEDs with graphene anodes has been limited by a lack of efficient methods to improve the low work function and reduce the sheet resistance of graphene films to the levels required for electrodes. Here, we fabricate flexible OLEDs by modifying the graphene anode to have a high work function and low sheet resistance, and thus achieve extremely high luminous efficiencies (37.2 lm W-1 in fluorescent OLEDs, 102.7 lm W-1 in phosphorescent OLEDs), which are significantly higher than those of optimized devices with an indium tin oxide anode (24.1 lm W-1 in fluorescent OLEDs, 85.6 lm W-1 in phosphorescent OLEDs). We also fabricate flexible white OLED lighting devices using the graphene anode. These results demonstrate the great potential of graphene anodes for use in a wide variety of high-performance flexible organic optoelectronics.

Minute synthesis of extremely stable gold nanoparticles.

PubMed

Zhou, Min; Wang, Baoxiang; Rozynek, Zbigniew; Xie, Zhaohui; Fossum, Jon Otto; Yu, Xiaofeng; Raaen, Steinar

2009-12-16

We describe a rapid environmentally friendly wet-chemical approach to synthesize extremely stable non-toxic, biocompatible, water-soluble monodispersed gold nanoparticles (AuNPs) in one step at room temperature. The particles have been successfully achieved in just a few minutes by merely adding sodium hydroxide (NaOH) acting as an initiator for the reduction of HAuCl(4) in aqueous solution in the presence of polyvinylpyrrolidone (PVP) without the use of any reducing agent. It is also proved to be highly efficient for the preparation of AuNPs with controllable sizes. The AuNPs show remarkable stability in water media with high concentrations of salt, various buffer solutions and physiological conditions in biotechnology and biomedicine. Moreover, the AuNPs are also non-toxic at high concentration (100 microM). Therefore, it provides great opportunities to use these AuNPs for biotechnology and biomedicine. This new approach also involved several green chemistry concepts, such as the selection of environmentally benign reagents and solvents, without energy consumption, and less reaction time.

Development of High-Resolution Dynamic Dust Source Function - A Case Study with a Strong Dust Storm in a Regional Model

NASA Technical Reports Server (NTRS)

Kim, Dongchul; Chin, Mian; Kemp, Eric M.; Tao, Zhining; Peters-Lidard, Christa D.; Ginoux, Paul

2017-01-01

A high-resolution dynamic dust source has been developed in the NASA Unified-Weather Research and Forecasting (NU-WRF) model to improve the existing coarse static dust source. In the new dust source map, topographic depression is in 1-km resolution and surface bareness is derived using the Normalized Difference Vegetation Index (NDVI) data from Moderate Resolution Imaging Spectroradiometer (MODIS). The new dust source better resolves the complex topographic distribution over the Western United States where its magnitude is higher than the existing, coarser resolution static source. A case study is conducted with an extreme dust storm that occurred in Phoenix, Arizona in 0203 UTC July 6, 2011. The NU-WRF model with the new high-resolution dynamic dust source is able to successfully capture the dust storm, which was not achieved with the old source identification. However the case study also reveals several challenges in reproducing the time evolution of the short-lived, extreme dust storm events.

Development of High-Resolution Dynamic Dust Source Function -A Case Study with a Strong Dust Storm in a Regional Model

PubMed Central

Kim, Dongchul; Chin, Mian; Kemp, Eric M.; Tao, Zhining; Peters-Lidard, Christa D.; Ginoux, Paul

2018-01-01

A high-resolution dynamic dust source has been developed in the NASA Unified-Weather Research and Forecasting (NU-WRF) model to improve the existing coarse static dust source. In the new dust source map, topographic depression is in 1-km resolution and surface bareness is derived using the Normalized Difference Vegetation Index (NDVI) data from Moderate Resolution Imaging Spectroradiometer (MODIS). The new dust source better resolves the complex topographic distribution over the Western United States where its magnitude is higher than the existing, coarser resolution static source. A case study is conducted with an extreme dust storm that occurred in Phoenix, Arizona in 02-03 UTC July 6, 2011. The NU-WRF model with the new high-resolution dynamic dust source is able to successfully capture the dust storm, which was not achieved with the old source identification. However the case study also reveals several challenges in reproducing the time evolution of the short-lived, extreme dust storm events. PMID:29632432

Development of High-Resolution Dynamic Dust Source Function -A Case Study with a Strong Dust Storm in a Regional Model.

PubMed

Kim, Dongchul; Chin, Mian; Kemp, Eric M; Tao, Zhining; Peters-Lidard, Christa D; Ginoux, Paul

2017-06-01

A high-resolution dynamic dust source has been developed in the NASA Unified-Weather Research and Forecasting (NU-WRF) model to improve the existing coarse static dust source. In the new dust source map, topographic depression is in 1-km resolution and surface bareness is derived using the Normalized Difference Vegetation Index (NDVI) data from Moderate Resolution Imaging Spectroradiometer (MODIS). The new dust source better resolves the complex topographic distribution over the Western United States where its magnitude is higher than the existing, coarser resolution static source. A case study is conducted with an extreme dust storm that occurred in Phoenix, Arizona in 02-03 UTC July 6, 2011. The NU-WRF model with the new high-resolution dynamic dust source is able to successfully capture the dust storm, which was not achieved with the old source identification. However the case study also reveals several challenges in reproducing the time evolution of the short-lived, extreme dust storm events.

Design and Control of a Closed-Loop Brushless Torque Activator

DTIC Science & Technology

1990-05-01

AD-A270 760 Technical Report 1244 Design and Control of a Closed-Loop Brushless Torque Activator Michael Dean Levi MIT Artificial Intelligence... Brushless N00014-86-K-0685 Torque Actuator 6. AUTHOR(S) Michael Dean Levin 7. PERFORMING ORGANIZATION NAME(S) AND ADORESS(ES) B. PERFORMING...200 words) This’report explores the design and control issues associated with a brushless actuator capable of achieving extremely high torque

The advantage of a decreasing right-hand superiority: the influence of laterality on a selected musical skill (sight reading achievement).

PubMed

Kopiez, Reinhard; Galley, Niels; Lee, Ji In

2006-01-01

In this study, the unrehearsed performance of music, known as 'sight reading', is used as a model to examine the influence of motoric laterality on highly challenging musical performance skills. As expertise research has shown, differences in this skill can be partially explained by factors such as accumulated practise and an early start to training. However, up until now, neurobiological factors that may influence highly demanding instrumental performance have been widely neglected. In an experiment with 52 piano students at a German university music department, we could show that the most challenging musical skill, sight reading (which is characterized by extreme demands on the performer's real time information processing), is positively correlated with decreasing right-hand superiority of performers. Laterality was measured by the differences between left and right-hand performance in a speed tapping task. SR achievement was measured using an accompanying task paradigm. An overall superiority of 22% for non-right-handed pianists was found. This effect is gender-related and stronger in non-right-handed males (r(24) = -0.49, p<0.05) than in non-right-handed females (r(28) = -0.16, p>0.05). We conclude that non-right-handed motoric laterality is associated with neurobiological advantages required for sight reading, an extremely demanding musical subskill.

Integrating Epitaxial-Like Pb(Zr,Ti)O3 Thin-Film into Silicon for Next-Generation Ferroelectric Field-Effect Transistor

PubMed Central

Park, Jae Hyo; Kim, Hyung Yoon; Jang, Gil Su; Seok, Ki Hwan; Chae, Hee Jae; Lee, Sol Kyu; Kiaee, Zohreh; Joo, Seung Ki

2016-01-01

The development of ferroelectric random-access memory (FeRAM) technology with control of grain boundaries would result in a breakthrough for new nonvolatile memory devices. The excellent piezoelectric and electrical properties of bulk ferroelectrics are degraded when the ferroelectric is processed into thin films because the grain boundaries then form randomly. Controlling the nature of nucleation and growth are the keys to achieving a good crystalline thin-film. However, the sought after high-quality ferroelectric thin-film has so far been thought to be impossible to make, and research has been restricted to atomic-layer deposition which is extremely expensive and has poor reproducibility. Here we demonstrate a novel epitaxial-like growth technique to achieve extremely uniform and large rectangular-shaped grains in thin-film ferroelectrics by dividing the nucleation and growth phases. With this technique, it is possible to achieve 100-μm large uniform grains, even made available on Si, which is large enough to fabricate a field-effect transistor in each grain. The electrical and reliability test results, including endurance and retention test results, were superior to other FeRAMs reported so far and thus the results presented here constitute the first step toward the development of FeRAM using epitaxial-like ferroelectric thin-films. PMID:27005886

Aging without Dementia is Achievable: Current Evidence from Epidemiological Research.

PubMed

Qiu, Chengxuan; Fratiglioni, Laura

2018-01-01

Both the incidence and the prevalence of dementia increase exponentially with increasing age. This raises the question of whether dementia is an inevitable consequence of aging or whether aging without dementia is achievable. In this review article, we sought to summarize the current evidence from epidemiological and neuropathological studies that investigated this topic. Epidemiological studies have shown that dementia could be avoided even at extreme old ages (e.g., centenarians or supercentenarians). Furthermore, clinico-neuropathological studies found that nearly half of centenarians with dementia did not have sufficient brain pathology to explain their cognitive symptoms, while intermediate-to-high Alzheimer pathology was present in around one-third of very old people without dementia or cognitive impairment. This suggests that certain compensatory mechanisms (e.g., cognitive reserve or resilience) may play a role in helping people in extreme old ages escape dementia syndrome. Finally, evidence has been accumulating in recent years indicating that the incidence of dementia has declined in Europe and North America, which supports the view that the risk of dementia in late life is modifiable. Evidence has emerged that intervention strategies that promote general health, maintain vascular health, and increase cognitive reserve are likely to help preserve cognitive function till late life, thus achieving the goal of aging without dementia.

Aging without Dementia is Achievable: Current Evidence from Epidemiological Research

PubMed Central

Qiu, Chengxuan; Fratiglioni, Laura

2018-01-01

Both the incidence and the prevalence of dementia increase exponentially with increasing age. This raises the question of whether dementia is an inevitable consequence of aging or whether aging without dementia is achievable. In this review article, we sought to summarize the current evidence from epidemiological and neuropathological studies that investigated this topic. Epidemiological studies have shown that dementia could be avoided even at extreme old ages (e.g., centenarians or supercentenarians). Furthermore, clinico-neuropathological studies found that nearly half of centenarians with dementia did not have sufficient brain pathology to explain their cognitive symptoms, while intermediate-to-high Alzheimer pathology was present in around one-third of very old people without dementia or cognitive impairment. This suggests that certain compensatory mechanisms (e.g., cognitive reserve or resilience) may play a role in helping people in extreme old ages escape dementia syndrome. Finally, evidence has been accumulating in recent years indicating that the incidence of dementia has declined in Europe and North America, which supports the view that the risk of dementia in late life is modifiable. Evidence has emerged that intervention strategies that promote general health, maintain vascular health, and increase cognitive reserve are likely to help preserve cognitive function till late life, thus achieving the goal of aging without dementia. PMID:29562544

Improved cycling cryopump

DOEpatents

Batzer, T.H.; Call, W.R.

1984-12-04

The present invention is designed to achieve continuous high efficiency cryopumping of a vacuum vessel by improving upon and combining in a novel way the cryopumping in a novel way the cryopumping methods. The invention consists of a continuous operation cryopump, with movable louvres, with a high efficiency pumping apparatus. The pumping apparatus includes three cryogenic tubes. They are constructed of a substance of high thermal conductivity, such as aluminum and their exterior surfaces are cryogenic condensing surfaces. Through their interior liquid or gaseous helium from two reservoirs can be made to flow, alternately promoting extreme cooling or allowing some warming.

Neighborhood Influences on the Academic Achievement of Extremely Low Birth Weight Children

PubMed Central

Borawski, Elaine; Schluchter, Mark; Taylor, H.Gerry; Klein, Nancy; Hack, Maureen

2010-01-01

Objective To examine neighborhood effects on academic achievement of children with extremely low birth weight (ELBW <1000 g) and normal birth weight (NBW) controls. Methods The study included 183 8-year-old children with ELBW born during 1992–1995 and 176 sociodemographically similar NBW controls. Academic achievement was measured via The Woodcock–Johnson III Academic Skills Cluster. Results Children with ELBW had significantly lower achievement scores (89 ± 16 vs. 97 ± 13). A multilevel estimation of predictors of academic achievement revealed that neighborhood poverty was significantly associated with lower achievement (β = −.17; 95% CI −.3, −.05; p < .01). Additional correlates included birth weight status, male sex, and parent ratings of attention deficit hyperactivity disorder symptoms. Family characteristics included maternal education and parent protection. Conclusions Neighborhood characteristics affect academic achievement of both children with ELBW and NBW controls, over and above individual and family influences. Interventions designed to address family and neighborhood factors may potentially improve these outcomes. PMID:19584171

Integrated nanomaterials for extreme thermal management: a perspective for aerospace applications

NASA Astrophysics Data System (ADS)

Barako, Michael T.; Gambin, Vincent; Tice, Jesse

2018-04-01

Nanomaterials will play a disruptive role in next-generation thermal management for high power electronics in aerospace platforms. These high power and high frequency devices have been experiencing a paradigm shift toward designs that favor extreme integration and compaction. The reduction in form factor amplifies the intensity of the thermal loads and imposes extreme requirements on the thermal management architecture for reliable operation. In this perspective, we introduce the opportunities and challenges enabled by rationally integrating nanomaterials along the entire thermal resistance chain, beginning at the high heat flux source up to the system-level heat rejection. Using gallium nitride radio frequency devices as a case study, we employ a combination of viewpoints comprised of original research, academic literature, and industry adoption of emerging nanotechnologies being used to construct advanced thermal management architectures. We consider the benefits and challenges for nanomaterials along the entire thermal pathway from synthetic diamond and on-chip microfluidics at the heat source to vertically-aligned copper nanowires and nanoporous media along the heat rejection pathway. We then propose a vision for a materials-by-design approach to the rational engineering of complex nanostructures to achieve tunable property combinations on demand. These strategies offer a snapshot of the opportunities enabled by the rational design of nanomaterials to mitigate thermal constraints and approach the limits of performance in complex aerospace electronics.

Integrated nanomaterials for extreme thermal management: a perspective for aerospace applications.

PubMed

Barako, Michael T; Gambin, Vincent; Tice, Jesse

2018-04-02

Nanomaterials will play a disruptive role in next-generation thermal management for high power electronics in aerospace platforms. These high power and high frequency devices have been experiencing a paradigm shift toward designs that favor extreme integration and compaction. The reduction in form factor amplifies the intensity of the thermal loads and imposes extreme requirements on the thermal management architecture for reliable operation. In this perspective, we introduce the opportunities and challenges enabled by rationally integrating nanomaterials along the entire thermal resistance chain, beginning at the high heat flux source up to the system-level heat rejection. Using gallium nitride radio frequency devices as a case study, we employ a combination of viewpoints comprised of original research, academic literature, and industry adoption of emerging nanotechnologies being used to construct advanced thermal management architectures. We consider the benefits and challenges for nanomaterials along the entire thermal pathway from synthetic diamond and on-chip microfluidics at the heat source to vertically-aligned copper nanowires and nanoporous media along the heat rejection pathway. We then propose a vision for a materials-by-design approach to the rational engineering of complex nanostructures to achieve tunable property combinations on demand. These strategies offer a snapshot of the opportunities enabled by the rational design of nanomaterials to mitigate thermal constraints and approach the limits of performance in complex aerospace electronics.

Measurement of absolute laser energy absorption by nano-structured targets

NASA Astrophysics Data System (ADS)

Park, Jaebum; Tommasini, R.; London, R.; Bargsten, C.; Hollinger, R.; Capeluto, M. G.; Shlyaptsev, V. N.; Rocca, J. J.

2017-10-01

Nano-structured targets have been reported to allow the realization of extreme plasma conditions using table top lasers, and have gained much interest as a platform to investigate the ultra-high energy density plasmas (>100 MJ/cm3) . One reason for these targets to achieve extreme conditions is increased laser energy absorption (LEA). The absolute LEA by nano-structured targets has been measured for the first time and compared to that by foil targets. The experimental results, including the effects of target parameters on the LEA, will be presented. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52097NA27344, and funded by LDRD (#15-ERD-054).

Levitation Performance of Two Opposed Permanent Magnet Pole-Pair Separated Conical Bearingless Motors

NASA Technical Reports Server (NTRS)

Kascak, Peter; Jansen, Ralph; Dever, Timothy; Nagorny, Aleksandr; Loparo, Kenneth

2013-01-01

In standard motor applications, rotor suspension with traditional mechanical bearings represents the most economical solution. However, in certain high performance applications, rotor suspension without contacting bearings is either required or highly beneficial. Examples include applications requiring very high speed or extreme environment operation, or with limited access for maintenance. This paper expands upon a novel bearingless motor concept, in which two motors with opposing conical air-gaps are used to achieve full five-axis levitation and rotation of the rotor. Force in this motor is created by deliberately leaving the motor s pole-pairs unconnected, which allows the creation of different d-axis flux in each pole pair. This flux imbalance is used to create lateral force. This approach is different than previous bearingless motor designs, which require separate windings for levitation and rotation. This paper examines the predicted and achieved suspension performance of a fully levitated prototype bearingless system.

Pressure profiles of the BRing based on the simulation used in the CSRm

NASA Astrophysics Data System (ADS)

Wang, J. C.; Li, P.; Yang, J. C.; Yuan, Y. J.; Wu, B.; Chai, Z.; Luo, C.; Dong, Z. Q.; Zheng, W. H.; Zhao, H.; Ruan, S.; Wang, G.; Liu, J.; Chen, X.; Wang, K. D.; Qin, Z. M.; Yin, B.

2017-07-01

HIAF-BRing, a new multipurpose accelerator facility of the High Intensity heavy-ion Accelerator Facility project, requires an extremely high vacuum lower than 10-11 mbar to fulfill the requirements of radioactive beam physics and high energy density physics. To achieve the required process pressure, the bench-marked codes of VAKTRAK and Molflow+ are used to simulate the pressure profiles of the BRing system. In order to ensure the accuracy of the implementation of VAKTRAK, the computational results are verified by measured pressure data and compared with a new simulation code BOLIDE on the current synchrotron CSRm. Since the verification of VAKTRAK has been done, the pressure profiles of the BRing are calculated with different parameters such as conductance, out-gassing rates and pumping speeds. According to the computational results, the optimal parameters are selected to achieve the required pressure for the BRing.

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.

Synthesis of ultra-nano-carbon composite materials with extremely high conductivity by plasma post-treatment process of ultrananocrystalline diamond films

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

Yeh, Chien-Jui; Leou, Keh-Chyang; Manoharan, Divinah

2015-08-24

Needle-like diamond grains encased in nano-graphitic layers are an ideal granular structure of diamond films to achieve high conductivity and superior electron field emission (EFE) properties. This paper describes the plasma post-treatment (ppt) of ultrananocrystalline diamond (UNCD) films at low substrate temperature to achieve such a unique granular structure. The CH{sub 4}/N{sub 2} plasma ppt-processed films exhibit high conductivity of σ = 1099 S/cm as well as excellent EFE properties with turn-on field of E{sub 0} = 2.48 V/μm (J{sub e} = 1.0 mA/cm{sup 2} at 6.5 V/μm). The ppt of UNCD film is simple and robust process that is especially useful for device applications.

High-dispersion spectroscopy of extrasolar planets: from CO in hot Jupiters to O2 in exo-Earths.

PubMed

Snellen, Ignas

2014-04-28

Ground-based high-dispersion spectroscopy could reveal molecular oxygen as a biomarker gas in the atmospheres of twin-Earths transiting red dwarf stars within the next 25 years. The required contrasts are only a factor of 3 lower than that already achieved for carbon monoxide in hot Jupiter atmospheres today but will need much larger telescopes because the target stars will be orders of magnitude fainter. If extraterrestrial life is very common and can therefore be found on planets around the most nearby red dwarf stars, it may be detectable via transmission spectroscopy with the next-generation extremely large telescopes. However, it is likely that significantly more collecting area is required for this. This can be achieved through the development of low-cost flux collector technology, which combines a large collecting area with a low but sufficient image quality for high-dispersion spectroscopy of bright stars.

Creating a global sub-daily precipitation dataset

NASA Astrophysics Data System (ADS)

Lewis, Elizabeth; Blenkinsop, Stephen; Fowler, Hayley

2017-04-01

Extremes of precipitation can cause flooding and droughts which can lead to substantial damages to infrastructure and ecosystems and can result in loss of life. It is still uncertain how hydrological extremes will change with global warming as we do not fully understand the processes that cause extreme precipitation under current climate variability. The INTENSE project is using a novel and fully-integrated data-modelling approach to provide a step-change in our understanding of the nature and drivers of global precipitation extremes and change on societally relevant timescales, leading to improved high-resolution climate model representation of extreme rainfall processes. The INTENSE project is in conjunction with the World Climate Research Programme (WCRP)'s Grand Challenge on 'Understanding and Predicting Weather and Climate Extremes' and the Global Water and Energy Exchanges Project (GEWEX) Science questions. The first step towards achieving this is to construct a new global sub-daily precipitation dataset. Data collection is ongoing and already covers North America, Europe, Asia and Australasia. Comprehensive, open source quality control software is being developed to set a new standard for verifying sub-daily precipitation data and a set of global hydroclimatic indices will be produced based upon stakeholder recommendations. This will provide a unique global data resource on sub-daily precipitation whose derived indices, e.g. monthly/annual maxima, will be freely available to the wider scientific community.

Time-resolved compression of a capsule with a cone to high density for fast-ignition laser fusion.

PubMed

Theobald, W; Solodov, A A; Stoeckl, C; Anderson, K S; Beg, F N; Epstein, R; Fiksel, G; Giraldez, E M; Glebov, V Yu; Habara, H; Ivancic, S; Jarrott, L C; Marshall, F J; McKiernan, G; McLean, H S; Mileham, C; Nilson, P M; Patel, P K; Pérez, F; Sangster, T C; Santos, J J; Sawada, H; Shvydky, A; Stephens, R B; Wei, M S

2014-12-12

The advent of high-intensity lasers enables us to recreate and study the behaviour of matter under the extreme densities and pressures that exist in many astrophysical objects. It may also enable us to develop a power source based on laser-driven nuclear fusion. Achieving such conditions usually requires a target that is highly uniform and spherically symmetric. Here we show that it is possible to generate high densities in a so-called fast-ignition target that consists of a thin shell whose spherical symmetry is interrupted by the inclusion of a metal cone. Using picosecond-time-resolved X-ray radiography, we show that we can achieve areal densities in excess of 300 mg cm(-2) with a nanosecond-duration compression pulse--the highest areal density ever reported for a cone-in-shell target. Such densities are high enough to stop MeV electrons, which is necessary for igniting the fuel with a subsequent picosecond pulse focused into the resulting plasma.

Optimization and phase matching of fiber-laser-driven high-order harmonic generation at high repetition rate.

PubMed

Cabasse, Amélie; Machinet, Guillaume; Dubrouil, Antoine; Cormier, Eric; Constant, Eric

2012-11-15

High-repetition-rate sources are very attractive for high-order harmonic generation (HHG). However, due to their pulse characteristics (low energy, long duration), those systems require a tight focusing geometry to achieve the necessary intensity to generate harmonics. In this Letter, we investigate theoretically and experimentally the optimization of HHG in this geometry, to maximize the extreme UV (XUV) photon flux and improve the conversion efficiency. We analyze the influence of atomic gas media (Ar, Kr, or Xe), gas pressure, and interaction geometries (a gas jet and a finite and a semi-infinite gas cell). Numerical simulations allow us to define optimal conditions for HHG in this tight focusing regime and to observe the signature of on-axis phase matching. These conditions are implemented experimentally using a high-repetition-rate Yb-doped fiber laser system. We achieve optimization of emission with a recorded XUV photon flux of 4.5×10(12) photons/s generated in Xe at 100 kHz repetition rate.

Achieving High Performance Perovskite Solar Cells

NASA Astrophysics Data System (ADS)

Yang, Yang

2015-03-01

Recently, metal halide perovskite based solar cell with the characteristics of rather low raw materials cost, great potential for simple process and scalable production, and extreme high power conversion efficiency (PCE), have been highlighted as one of the most competitive technologies for next generation thin film photovoltaic (PV). In UCLA, we have realized an efficient pathway to achieve high performance pervoskite solar cells, where the findings are beneficial to this unique materials/devices system. Our recent progress lies in perovskite film formation, defect passivation, transport materials design, interface engineering with respect to high performance solar cell, as well as the exploration of its applications beyond photovoltaics. These achievements include: 1) development of vapor assisted solution process (VASP) and moisture assisted solution process, which produces perovskite film with improved conformity, high crystallinity, reduced recombination rate, and the resulting high performance; 2) examination of the defects property of perovskite materials, and demonstration of a self-induced passivation approach to reduce carrier recombination; 3) interface engineering based on design of the carrier transport materials and the electrodes, in combination with high quality perovskite film, which delivers 15 ~ 20% PCEs; 4) a novel integration of bulk heterojunction to perovskite solar cell to achieve better light harvest; 5) fabrication of inverted solar cell device with high efficiency and flexibility and 6) exploration the application of perovskite materials to photodetector. Further development in film, device architecture, and interfaces will lead to continuous improved perovskite solar cells and other organic-inorganic hybrid optoelectronics.

Reproducable Paraplegia by Thoracic Aortic Occlusion in a Murine Model of Spinal Cord Ischemia-reperfusion

PubMed Central

Bell, Marshall T.; Reece, T. Brett; Smith, Phillip D.; Mares, Joshua; Weyant, Michael J.; Cleveland, Joseph C.; Freeman, Kirsten A.; Fullerton, David A.; Puskas, Ferenc

2014-01-01

Background Lower extremity paralysis continues to complicate aortic interventions. The lack of understanding of the underlying pathology has hindered advancements to decrease the occurrence this injury. The current model demonstrates reproducible lower extremity paralysis following thoracic aortic occlusion. Methods Adult male C57BL6 mice were anesthetized with isoflurane. Through a cervicosternal incision the aorta was exposed. The descending thoracic aorta and left subclavian arteries were identified without entrance into pleural space. Skeletonization of these arteries was followed by immediate closure (Sham) or occlusion for 4 min (moderate ischemia) or 8 min (prolonged ischemia). The sternotomy and skin were closed and the mouse was transferred to warming bed for recovery.  Following recovery, functional analysis was obtained at 12 hr intervals until 48 hr. Results Mice that underwent sham surgery showed no observable hind limb deficit. Mice subjected to moderate ischemia for 4 min had minimal functional deficit at 12 hr followed by progression to complete paralysis at 48 hr. Mice subjected to prolonged ischemia had an immediate paralysis with no observable hind-limb movement at any point in the postoperative period. There was no observed intraoperative or post operative mortality. Conclusion Reproducible lower extremity paralysis whether immediate or delayed can be achieved in a murine model. Additionally, by using a median sternotomy and careful dissection, high survival rates, and reproducibility can be achieved. PMID:24637534

Reproducable paraplegia by thoracic aortic occlusion in a murine model of spinal cord ischemia-reperfusion.

PubMed

Bell, Marshall T; Reece, T Brett; Smith, Phillip D; Mares, Joshua; Weyant, Michael J; Cleveland, Joseph C; Freeman, Kirsten A; Fullerton, David A; Puskas, Ferenc

2014-03-03

Lower extremity paralysis continues to complicate aortic interventions. The lack of understanding of the underlying pathology has hindered advancements to decrease the occurrence this injury. The current model demonstrates reproducible lower extremity paralysis following thoracic aortic occlusion. Adult male C57BL6 mice were anesthetized with isoflurane. Through a cervicosternal incision the aorta was exposed. The descending thoracic aorta and left subclavian arteries were identified without entrance into pleural space. Skeletonization of these arteries was followed by immediate closure (Sham) or occlusion for 4 min (moderate ischemia) or 8 min (prolonged ischemia). The sternotomy and skin were closed and the mouse was transferred to warming bed for recovery. Following recovery, functional analysis was obtained at 12 hr intervals until 48 hr. Mice that underwent sham surgery showed no observable hind limb deficit. Mice subjected to moderate ischemia for 4 min had minimal functional deficit at 12 hr followed by progression to complete paralysis at 48 hr. Mice subjected to prolonged ischemia had an immediate paralysis with no observable hind-limb movement at any point in the postoperative period. There was no observed intraoperative or post operative mortality. Reproducible lower extremity paralysis whether immediate or delayed can be achieved in a murine model. Additionally, by using a median sternotomy and careful dissection, high survival rates, and reproducibility can be achieved.

Birthweight-discordance and differences in early parenting relate to monozygotic twin differences in behaviour problems and academic achievement at age 7.

PubMed

Asbury, Kathryn; Dunn, Judith F; Plomin, Robert

2006-03-01

This longitudinal monozygotic (MZ) twin differences study explored associations between birthweight and early family environment and teacher-rated behaviour problems and academic achievement at age 7. MZ differences in anxiety, hyperactivity, conduct problems, peer problems and academic achievement correlated significantly with MZ differences in birthweight and early family environment, showing effect sizes of up to 2%. As predicted by earlier research, associations increased at the extremes of discordance, even in a longitudinal, cross-rater design, with effect sizes reaching as high as 12%. As with previous research some of these non-shared environmental (NSE) relationships appeared to operate partly as a function of SES, family chaos and maternal depression. Higher-risk families generally showed stronger negative associations.

Giant topological nontrivial band gaps in chloridized gallium bismuthide.

PubMed

Li, Linyang; Zhang, Xiaoming; Chen, Xin; Zhao, Mingwen

2015-02-11

Quantum spin Hall (QSH) effect is promising for achieving dissipationless transport devices but presently is achieved only at extremely low temperature. Searching for the large-gap QSH insulators with strong spin-orbit coupling (SOC) is the key to increase the operating temperature. We demonstrate theoretically that this can be solved in the chloridized gallium bismuthide (GaBiCl2) monolayer, which has nontrivial gaps of 0.95 eV at the Γ point, and 0.65 eV for bulk, as well as gapless edge states in the nanoribbon structures. The nontrivial gaps due to the band inversion and SOC are robust against external strain. The realization of the GaBiCl2 monolayer will be beneficial for achieving QSH effect and related applications at high temperatures.

Determining the mechanical constitutive properties of metals as a function of strain rate and temperature: A combined experimental and modeling approach

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

I. M. Robertson; A. Beaudoin; J. Lambros

2004-01-05

OAK-135 Development and validation of constitutive models for polycrystalline materials subjected to high strain rate loading over a range of temperatures are needed to predict the response of engineering materials to in-service type conditions (foreign object damage, high-strain rate forging, high-speed sheet forming, deformation behavior during forming, response to extreme conditions, etc.). To account accurately for the complex effects that can occur during extreme and variable loading conditions, requires significant and detailed computational and modeling efforts. These efforts must be closely coupled with precise and targeted experimental measurements that not only verify the predictions of the models, but also providemore » input about the fundamental processes responsible for the macroscopic response. Achieving this coupling between modeling and experimentation is the guiding principle of this program. Specifically, this program seeks to bridge the length scale between discrete dislocation interactions with grain boundaries and continuum models for polycrystalline plasticity. Achieving this goal requires incorporating these complex dislocation-interface interactions into the well-defined behavior of single crystals. Despite the widespread study of metal plasticity, this aspect is not well understood for simple loading conditions, let alone extreme ones. Our experimental approach includes determining the high-strain rate response as a function of strain and temperature with post-mortem characterization of the microstructure, quasi-static testing of pre-deformed material, and direct observation of the dislocation behavior during reloading by using the in situ transmission electron microscope deformation technique. These experiments will provide the basis for development and validation of physically-based constitutive models, which will include dislocation-grain boundary interactions for polycrystalline systems. One aspect of the program will involve the dire ct observation of specific mechanisms of micro-plasticity, as these will indicate the boundary value problem that should be addressed. This focus on the pre-yield region in the quasi-static effort (the elasto-plastic transition) is also a tractable one from an experimental and modeling viewpoint. In addition, our approach will minimize the need to fit model parameters to experimental data to obtain convergence. These are critical steps to reach the primary objective of simulating and modeling material performance under extreme loading conditions. In this annual report, we describe the progress made in the first year of this program.« less

Development of a miniature Stirling cryocooler for LWIR small satellite applications

NASA Astrophysics Data System (ADS)

Kirkconnell, C. S.; Hon, R. C.; Perella, M. D.; Crittenden, T. M.; Ghiaasiaan, S. M.

2017-05-01

The optimum small satellite (SmallSat) cryocooler system must be extremely compact and lightweight, achieved in this paper by operating a linear cryocooler at a frequency of approximately 300 Hz. Operation at this frequency, which is well in excess of the 100-150 Hz reported in recent papers on related efforts, requires an evolution beyond the traditional Oxford-class, flexure-based methods of setting the mechanical resonance. A novel approach that optimizes the electromagnetic design and the mechanical design together to simultaneously achieve the required dynamic and thermodynamic performances is described. Since highly miniaturized pulse tube coolers are fundamentally ill-suited for the sub-80K temperature range of interest because the boundary layer losses inside the pulse tube become dominant at the associated very small pulse tube size, a moving displacer Stirling cryocooler architecture is used. Compact compressor mechanisms developed on a previous program are reused for this design, and they have been adapted to yield an extremely compact Stirling warm end motor mechanism. Supporting thermodynamic and electromagnetic analysis results are reported.

An assessment of the real-time application capabilities of the SIFT computer system

NASA Technical Reports Server (NTRS)

Butler, R. W.

1982-01-01

The real-time capabilities of the SIFT computer system, a highly reliable multicomputer architecture developed to support the flight controls of a relaxed static stability aircraft, are discussed. The SIFT computer system was designed to meet extremely high reliability requirements and to facilitate a formal proof of its correctness. Although SIFT represents a significant achievement in fault-tolerant system research it presents an unusual and restrictive interface to its users. The characteristics of the user interface and its impact on application system design are assessed.

Xenon detector with high energy resolution for gamma-ray line emission registration

NASA Astrophysics Data System (ADS)

Novikov, Alexander S.; Ulin, Sergey E.; Chernysheva, Irina V.; Dmitrenko, Valery V.; Grachev, Victor M.; Petrenko, Denis V.; Shustov, Alexander E.; Uteshev, Ziyaetdin M.; Vlasik, Konstantin F.

2014-09-01

A description of the xenon detector (XD) for gamma-ray line emission registration is presented. The detector provides high energy resolution and is able to operate under extreme environmental conditions (wide temperature range and unfavorable acoustic action). Resistance to acoustic noise as well as improvement in energy resolution has been achieved by means of real-time digital pulse processing. Another important XD feature is the ionization chamber's thin wall with composite housing, which significantly decreases the mass of the device and expands its energy range, especially at low energies.

[Process strategy for ethanol production from lignocellulose feedstock under extremely low water usage and high solids loading conditions].

PubMed

Zhang, Jian; Chu, Deqiang; Yu, Zhanchun; Zhang, Xiaoxi; Deng, Hongbo; Wang, Xiusheng; Zhu, Zhinan; Zhang, Huaiqing; Dai, Gance; Bao, Jie

2010-07-01

The massive water and steam are consumed in the production of cellulose ethanol, which correspondingly results in the significant increase of energy cost, waster water discharge and production cost as well. In this study, the process strategy under extremely low water usage and high solids loading of corn stover was investigated experimentally and computationally. The novel pretreatment technology with zero waste water discharge was developed; in which a unique biodetoxification method using a kerosene fungus strain Amorphotheca resinae ZN1 to degrade the lignocellulose derived inhibitors was applied. With high solids loading of pretreated corn stover, high ethanol titer was achieved in the simultaneous saccharification and fermentation process, and the scale-up principles were studied. Furthermore, the flowsheet simulation of the whole process was carried out with the Aspen plus based physical database, and the integrated process developed was tested in the biorefinery mini-plant. Finally, the core technologies were applied in the cellulose ethanol demonstration plant, which paved a way for the establishment of an energy saving and environment friendly technology of lignocellulose biotransformation with industry application potential.

High Contrast Imaging in the Visible: First Experimental Results at the Large Binocular Telescope

NASA Astrophysics Data System (ADS)

Pedichini, F.; Stangalini, M.; Ambrosino, F.; Puglisi, A.; Pinna, E.; Bailey, V.; Carbonaro, L.; Centrone, M.; Christou, J.; Esposito, S.; Farinato, J.; Fiore, F.; Giallongo, E.; Hill, J. M.; Hinz, P. M.; Sabatini, L.

2017-08-01

In 2014 February, the System for High contrast And coronography from R to K at VISual bands (SHARK-VIS) Forerunner, a high contrast experimental imager operating at visible wavelengths, was installed at the Large Binocular Telescope (LBT). Here we report on the first results obtained by recent on-sky tests. These results show the extremely good performance of the LBT Extreme Adaptive Optics (ExAO) system at visible wavelengths, both in terms of spatial resolution and contrast achieved. Similarly to what was done by Amara & Quanz (2012), we used the SHARK-VIS Forerunner data to quantitatively assess the contrast enhancement. This is done by injecting several different synthetic faint objects in the acquired data and applying the angular differential imaging (ADI) technique. A contrast of the order of 5 × 10-5 is obtained at 630 nm for angular separations from the star larger than 100 mas. These results are discussed in light of the future development of SHARK-VIS and compared to those obtained by other high contrast imagers operating at similar wavelengths.

Beef customer satisfaction: USDA quality grade and marination effects on consumer evaluations of top round steaks.

PubMed

Behrends, J M; Goodson, K J; Koohmaraie, M; Shackelford, S D; Wheeler, T L; Morgan, W W; Reagan, J O; Gwartney, B L; Wise, J W; Savell, J W

2005-03-01

An in-home beef study evaluated consumer ratings of top round steaks (semimembranosus) as influenced by USDA quality grade (top Choice or high Select), city (Chicago or Philadelphia), consumer segment (beef loyalists = heavy consumers of beef; budget rotators = cost-driven and split meat consumption between beef and chicken; and variety rotators = higher incomes and education and split meat consumption among beef, poultry, and other foods), degree of doneness, cooking method, and marination. Consumers evaluated each steak for overall like, tenderness, juiciness, flavor like, and flavor amount using 10-point scales (1 = dislike extremely, not at all tender, not at all juicy, dislike extremely, and none at all to 10 = like extremely, extremely tender, extremely juicy, like extremely, and an extreme amount of flavor, respectively). Quality grade affected several consumer sensory traits, with top Choice receiving higher (P < or = 0.004) tenderness, juiciness, and flavor like scores than high Select. Consumers in Chicago rated steaks cooked "medium and less" higher for overall like, tenderness, juiciness, flavor like, and flavor amount than those in Philadelphia (city x degree of doneness; P < or = 0.020). Steaks braised by customers in Philadelphia received among the highest scores for overall like, tenderness, juiciness, flavor like, and flavor amount compared with any cooking method used by customers in Chicago (cooking method x city; P < or = 0.026). Overall like and flavor amount ratings were least (P < 0.05) for steaks that were marinated and cooked to "medium and less" degree of doneness (marination x degree of doneness; P < or = 0.014). Braised steaks received among the highest values for overall like, tenderness, juiciness, flavor like, and flavor amount when cooked to "medium and less" or "medium well and more" (cooking method x degree of doneness; P < or = 0.008). Correlation and stepwise regression analysis indicated that flavor like was pivotal in customers' satisfaction with top round steaks, and was the sensory trait most highly correlated to overall like, followed by tenderness, flavor amount, and juiciness. Preparation of top round steaks was crucial in consumers' likes and dislikes, and by improving flavor, higher consumer satisfaction may be achieved.

Cyanopyridine Based Bipolar Host Materials for Green Electrophosphorescence with Extremely Low Turn-On Voltages and High Power Efficiencies.

PubMed

Li, Wei; Li, Jiuyan; Liu, Di; Li, Deli; Wang, Fang

2016-08-24

Low driving voltage and high power efficiency are basic requirements when practical applications of organic light emitting diodes (OLEDs) in displays and lighting are considered. Two novel host materials m-PyCNmCP and 3-PyCNmCP incorporating cyanopyridine moiety as electron-transporting unit are developed for use in fac-tris(2-phenylpyridine)iridium(III) (Ir(ppy)3) based green phosphorescent OLEDs (PhOLEDs). Extremely low turn-on voltages of 2.01 and 2.27 V are realized, which are even lower than the theoretical limit of the emitted photon energy (hv)/electron charge (e) (2.37 V) of Ir(ppy)3. High power efficiency of 101.4 lm/W (corresponding to a maximum external quantum efficiency of 18.4%) and 119.3 lm/W (24.7%) are achieved for m-PyCNmCP and 3-PyCNmCP based green PhOLEDs. The excellent EL performance benefits from the ideal parameters of host materials by combining cyano and pyridine to enhance the n-type feature. The energetic favorable alignment of HOMO/LUMO levels of hosts with adjacent layers and the dopant for easy charge injections and direct charge trapping by dopant, their bipolar feature to balance charge transportations, sufficiently high triplet energy and small singlet/triplet energy difference (0.38 and 0.43 eV) combine to be responsible for the extremely low driving voltages and high power efficiencies of the green PhOLEDs.

Neutron Time-of-Flight Diffractometer HIPPO at LANSCE

NASA Astrophysics Data System (ADS)

Vogel, Sven; Williams, Darrick; Zhao, Yusheng; Bennett, Kristin; von Dreele, Bob; Wenk, Hans-Rudolf

2004-03-01

The High-Pressure Preferred Orientation (HIPPO) neutron diffractometer is the first third-generation neutron time-of-flight powder diffractometer to be constructed in the United States. It produces extremely high intensity by virtue of a short (9 m) initial flight path on a high intensity water moderator and 1380 3He detector tubes covering 4.5 m2 of detector area from 10' to 150' in scattering angles. HIPPO was designed and manufactured as a joint effort between LANSCE and University of California with the goals of attaining world-class science and making neutron powder diffractometry an accessible and available tool to the national user community. Over two decades of momentum transfer are available (0.1-30 A-1) to support studies of amorphous solids; magnetic diffraction; small crystalline samples; and samples subjected to extreme environments such as temperature, pressure, or magnetic fields. The exceptionally high data rates of HIPPO also make it useful for time-resolved studies. In addition to the standard ancillary equipment (100-position sample/texture changer, closed-cycle He refrigerator, furnace), HIPPO has unique high-pressure cells capable of achieving pressures of 30 GPA at ambient and high (2000 K) temperature with samples up to 100 mm3 in volume.

Quantitative methods for stochastic high frequency spatio-temporal and non-linear analysis: Assessing health effects of exposure to extreme ambient temperature

NASA Astrophysics Data System (ADS)

Liss, Alexander

Extreme weather events, such as heat waves and cold spells, cause substantial excess mortality and morbidity in the vulnerable elderly population, and cost billions of dollars. The accurate and reliable assessment of adverse effects of extreme weather events on human health is crucial for environmental scientists, economists, and public health officials to ensure proper protection of vulnerable populations and efficient allocation of scarce resources. However, the methodology for the analysis of large national databases is yet to be developed. The overarching objective of this dissertation is to examine the effect of extreme weather on the elderly population of the Conterminous US (ConUS) with respect to seasonality in temperature in different climatic regions by utilizing heterogeneous high frequency and spatio-temporal resolution data. To achieve these goals the author: 1) incorporated dissimilar stochastic high frequency big data streams and distinct data types into the integrated data base for use in analytical and decision support frameworks; 2) created an automated climate regionalization system based on remote sensing and machine learning to define climate regions for the Conterminous US; 3) systematically surveyed the current state of the art and identified existing gaps in the scientific knowledge; 4) assessed the dose-response relationship of exposure to temperature extremes on human health in relatively homogeneous climate regions using different statistical models, such as parametric and non-parametric, contemporaneous and asynchronous, applied to the same data; 5) assessed seasonal peak timing and synchronization delay of the exposure and the disease within the framework of contemporaneous high frequency harmonic time series analysis and modification of the effect by the regional climate; 6) modeled using hyperbolic functional form non-linear properties of the effect of exposure to extreme temperature on human health. The proposed climate regionalization method algorithmically forms eight climatically homogeneous regions for Conterminous US from satellite Remote Sensing inputs. The relative risk of hospitalizations due to extreme ambient temperature varied across climatic regions. Difference in regional hospitalization rates suggests presence of an adaptation effect to a prevailing climate. In various climatic regions the hospitalizations peaked earlier than the peak of exposure. This suggests disproportionally high impact of extreme weather events, such as cold spells or heat waves when they occur early in the season. These findings provide an insight into the use of high frequency disjoint data sets for the assessment of the magnitude, timing, synchronization and non-linear properties of adverse health consequences due to exposure to extreme weather events to the elderly in defined climatic regions. These findings assist in the creation of decision support frameworks targeting preventions and adaptation strategies such as improving infrastructure, providing energy assistance, education and early warning notifications for the vulnerable population. This dissertation offers a number of methodological innovations for the assessment of the high frequency spatio-temporal and non-linear impacts of extreme weather events on human health. These innovations help to ensure an improved protection of the elderly population, aid policy makers in the development of efficient disaster prevention strategies, and facilitate more efficient allocation of scarce resources.

Possible alternatives to critical elements in coatings for extreme applications

NASA Astrophysics Data System (ADS)

Grilli, Maria Luisa; Valerini, Daniele; Piticescu, Radu Robert; Bellezze, Tiziano; Yilmaz, Mehmet; Rinaldi, Antonio; Cuesta-López, Santiago; Rizzo, Antonella

2018-03-01

Surface functionalisation and protection have been used since a long time for improving specific properties of materials such as lubrication, water repellence, brightness, and for increasing durability of objects and tools. Among the different kinds of surface treatments used to achieve the required properties, the use of coatings is fundamental to guarantee substrate durability in harsh environments. Extreme working conditions of temperature, pressure, irradiation, wear and corrosion occur in several applications, thus very often requiring bulk material protection by means of coatings. In this study, three main classes of coatings used in extreme conditions are considered: i) hard and superhard coatings for application in machining tools, ii) coatings for high temperatures (thermal barrier coatings), and iii) coatings against corrosion. The presence of critical elements in such coatings (Cr, Y, W, Co, etc.) is analysed and the possibility to use CRMs-free substitutes is reviewed. The role of multilayers and nanocomposites in tailoring coating performances is also discussed for thermal barrier and superhard coatings.

Surgical Management of Complex Lower-Extremity Trauma With a Long Hindfoot Fusion Nail: A Case Report.

PubMed

Jain, Nickul S; Lopez, Gregory D; Bederman, S Samuel; Wirth, Garrett A; Scolaro, John A

2016-08-01

High-energy injuries can result in complete or partial loss of the talus. Ipsilateral fractures to the lower limb increase the complexity of surgical management, and treatment is guided by previous case reports of similar injuries. A case of complex lower-extremity trauma with extruded and missing talar body and ipsilateral type IIIB open tibia fracture is presented. Surgical limb reconstruction and salvage was performed successfully with a single orthopaedic implant in a manner not described previously in the literature. The purpose of this case report is to present the novel use of a single orthopaedic implant for treatment of a complex, open traumatic injury. Previous case reports in the literature have described the management of complete or partial talar loss. We describe the novel use of a long hindfoot fusion nail and staged bone grafting to achieve tibiocalcaneal arthrodesis for the treatment of complex lower-extremity trauma. Therapeutic, Level IV: Case study. © 2015 The Author(s).

A Large-Scale Multi-Hop Localization Algorithm Based on Regularized Extreme Learning for Wireless Networks.

PubMed

Zheng, Wei; Yan, Xiaoyong; Zhao, Wei; Qian, Chengshan

2017-12-20

A novel large-scale multi-hop localization algorithm based on regularized extreme learning is proposed in this paper. The large-scale multi-hop localization problem is formulated as a learning problem. Unlike other similar localization algorithms, the proposed algorithm overcomes the shortcoming of the traditional algorithms which are only applicable to an isotropic network, therefore has a strong adaptability to the complex deployment environment. The proposed algorithm is composed of three stages: data acquisition, modeling and location estimation. In data acquisition stage, the training information between nodes of the given network is collected. In modeling stage, the model among the hop-counts and the physical distances between nodes is constructed using regularized extreme learning. In location estimation stage, each node finds its specific location in a distributed manner. Theoretical analysis and several experiments show that the proposed algorithm can adapt to the different topological environments with low computational cost. Furthermore, high accuracy can be achieved by this method without setting complex parameters.

Preferentially Oriented Ag Nanocrystals with Extremely High Activity and Faradaic Efficiency for CO2 Electrochemical Reduction to CO.

PubMed

Peng, Xiong; Karakalos, Stavros G; Mustain, William E

2018-01-17

Selective electrochemical reduction of CO 2 is one of the most important processes to study because of its promise to convert this greenhouse gas to value-added chemicals at low cost. In this work, a simple anodization treatment was devised that first oxidizes Ag to Ag 2 CO 3 , then uses rapid electrochemical reduction to create preferentially oriented nanoparticles (PONs) of metallic Ag (PON-Ag) with high surface area as well as high activity and very high selectivity for the reduction of CO 2 to CO. The PON-Ag catalyst was dominated by (110) and (100) orientation, which allowed PON-Ag to achieve a CO Faradaic efficiency of 96.7% at an operating potential of -0.69 V vs RHE. This performance is not only significantly higher than that of polycrystalline Ag (60% at -0.87 V vs RHE) but also represents one of the best combinations of activity and selectivity achieved to date - all with a very simple, scalable approach to electrode fabrication.

HIGH-SPEED IMAGING AND WAVEFRONT SENSING WITH AN INFRARED AVALANCHE PHOTODIODE ARRAY

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

Baranec, Christoph; Atkinson, Dani; Hall, Donald

2015-08-10

Infrared avalanche photodiode (APD) arrays represent a panacea for many branches of astronomy by enabling extremely low-noise, high-speed, and even photon-counting measurements at near-infrared wavelengths. We recently demonstrated the use of an early engineering-grade infrared APD array that achieves a correlated double sampling read noise of 0.73 e{sup −} in the lab, and a total noise of 2.52 e{sup −} on sky, and supports simultaneous high-speed imaging and tip-tilt wavefront sensing with the Robo-AO visible-light laser adaptive optics (AO) system at the Palomar Observatory 1.5 m telescope. Here we report on the improved image quality simultaneously achieved at visible andmore » infrared wavelengths by using the array as part of an image stabilization control loop with AO-sharpened guide stars. We also discuss a newly enabled survey of nearby late M-dwarf multiplicity, as well as future uses of this technology in other AO and high-contrast imaging applications.« less

Advanced components for spaceborne infrared astronomy

NASA Technical Reports Server (NTRS)

Davidson, A. W.

1984-01-01

The need for improved cryogenic components to be used in future spaceborne infrared astronomy missions was identified. Improved low noise cryogenic amplifiers operated with infrared detectors, and better cryogenic actuators and motors with extremely low power dissipation are needed. The feasibility of achieving technological breakthroughs in both of these areas was studied. An improved silicon junction field effect transistor (JFET) could be developed if: (1) high purity silicon; (2) optimum dopants; and (3) very high doping levels are used. The feasibility of a simple stepper motor equipped with superconducting coils is demonstrated by construction of such a device based on a standard commercial motor. It is found that useful levels of torque at immeasurably low power levels were achieved. It is concluded that with modest development and optimization efforts, significant performance gains is possible for both cryogenic preamplifiers and superconducting motors and actuators.

Outcomes of catheter-directed treatment of lower extremity deep vein thrombosis of patients presenting to a tertiary care hospital.

PubMed

Sundar, Gaurav; Keshava, Shyamkumar N; Moses, Vinu; Chiramel, George K; Ahmed, Munawwar; Mammen, Suraj; Aggarwal, Sunil; Stephen, Edwin

2016-01-01

Lower extremity deep vein thrombosis (DVT) is a common illness with an annual incidence of 1 per 1000 adults. The major long-term complication of DVT is post-thrombotic syndrome (PTS) which occurs in up to 60% of patients within 2 years of an episode of DVT. We aim to evaluate the outcomes of catheter-directed treatment (CDT) for symptomatic acute or subacute lower extremity DVT. A retrospective 12-year study was conducted on the outcomes of CDT on 54 consecutive patients who presented with acute or subacute lower extremity DVT to our hospital. Descriptive summary statistics and the Chi-square test were used to measure the outcomes of CDT. Grade 3 thrombolysis was achieved in 25 (46.3%) patients, grade 2 thrombolysis in 25 (46.3%) patients, and grade 1 thrombolysis in 4 (7.4%) patients. Significant recanalization (grade 2 or 3 thrombolysis) was possible in 50 (92.6%) patients. There was no statistically significant difference in the percentage of significant recanalization that could be achieved between patients who underwent CDT before and after 10 days. There was no significant difference between the thrombolysis achieved between urokinase and r-tPA. PTS was seen in 33% of the patients. Major complications were seen in 5.5% of the patients. CDT is a safe and effective therapeutic technique in patients with acute and subacute lower extremity DVT, if appropriate patient selection is made.

Strong Field-Induced Frequency Conversion of Laser Radiation in Plasma Plumes: Recent Achievements

PubMed Central

Ganeev, R. A.

2013-01-01

New findings in plasma harmonics studies using strong laser fields are reviewed. We discuss recent achievements in the growth of the efficiency of coherent extreme ultraviolet (XUV) radiation sources based on frequency conversion of the ultrashort pulses in the laser-produced plasmas, which allowed for the spectral and structural studies of matter through the high-order harmonic generation (HHG) spectroscopy. These studies showed that plasma HHG can open new opportunities in many unexpected areas of laser-matter interaction. Besides being considered as an alternative method for generation of coherent XUV radiation, it can be used as a powerful tool for various spectroscopic and analytical applications. PMID:23864818

Peripheral neurolymphomatosis with tracheal asphyxia: a case report and literature review.

PubMed

Liu, Zuofeng; Jiang, Tao; Hou, Ni; Jia, Yongqian

2015-08-23

Neurolymphomatosis (NL) is an extremely rare disease and tracheal asphyxia due to NL has not been previously reported. A 54-year-old Chinese woman with a history of diffuse large B-cell lymphoma in her first complete remission developed peripheral neuropathy and tracheal asphyxia. Neurolymphomatosis involving the right brachial plexus and the right vagus nerve was demonstrated by PET/CT, but not by MRI. She underwent urgent tracheotomy and impact chemotherapy using rituximab combined with high dose methotrexate and involved field radiotherapy. She achieved a second complete remission. PET/CT plays valuable role in differentiating NL from other neuropathies in patients with lymphoma. Complete remission can be achieved in NL due to large B-cell lymphoma.

Thermal Optimization of an On-Orbit Long Duration Cryogenic Propellant Depot

NASA Technical Reports Server (NTRS)

Honour, Ryan; Kwas, Robert; O'Neil, Gary; Kutter, Gary

2012-01-01

A Cryogenic Propellant Depot (CPD) operating in Low Earth Orbit (LEO) could provide many near term benefits to NASA's space exploration efforts. These benefits include elongation/extension of spacecraft missions and requirement reduction of launch vehicle up-mass. Some of the challenges include controlling cryogenic propellant evaporation and managing the high costs and long schedules associated with the new development of spacecraft hardware. This paper describes a conceptual CPD design that is thermally optimized to achieve extremely low propellant boil-off rates. The CPD design is based on existing launch vehicle architecture, and its thermal optimization is achieved using current passive thermal control technology. Results from an integrated thermal model are presented showing that this conceptual CPD design can achieve propellant boil-off rates well under 0.05% per day, even when subjected to the LEO thermal environment.

Thermal Optimization and Assessment of a Long Duration Cryogenic Propellant Depot

NASA Technical Reports Server (NTRS)

Honour, Ryan; Kwas, Robert; O'Neil, Gary; Kutter, Bernard

2012-01-01

A Cryogenic Propellant Depot (CPD) operating in Low Earth Orbit (LEO) could provide many near term benefits to NASA space exploration efforts. These benefits include elongation/extension of spacecraft missions and reduction of launch vehicle up-mass requirements. Some of the challenges include controlling cryogenic propellant evaporation and managing the high costs and long schedules associated with new spacecraft hardware development. This paper describes a conceptual CPD design that is thermally optimized to achieve extremely low propellant boil-off rates. The CPD design is based on existing launch vehicle architecture, and its thermal optimization is achieved using current passive thermal control technology. Results from an integrated thermal model are presented showing that this conceptual CPD design can achieve propellant boil-off rates well under 0.05% per day, even when subjected to the LEO thermal environment.

Toward Zero Micro/Macro-Scale Wear Using Periodic Nano-Layered Coatings.

PubMed

Penkov, Oleksiy V; Devizenko, Alexander Yu; Khadem, Mahdi; Zubarev, Evgeniy N; Kondratenko, Valeriy V; Kim, Dae-Eun

2015-08-19

Wear is an important phenomenon that affects the efficiency and life of all moving machines. In this regard, extensive efforts have been devoted to achieve the lowest possible wear in sliding systems. With the advent of novel materials in recent years, technology is moving toward realization of zero wear. Here, we report on the development of new functional coatings comprising periodically stacked nanolayers of amorphous carbon and cobalt that are extremely wear resistant at the micro and macro scale. Because of their unique structure, these coatings simultaneously provide high elasticity and ultrahigh shear strength. As a result, almost zero wear was observed even after one million sliding cycles without any lubrication. The wear rate was reduced by 8-10-fold compared with the best previously reported data on extremely low wear materials.

Novel high-strength biocomposites based on microfibrillated cellulose having nano-order-unit web-like network structure

NASA Astrophysics Data System (ADS)

Nakagaito, A. N.; Yano, H.

2005-01-01

A completely new kind of high-strength composite was manufactured using microfibrillated cellulose (MFC) derived from kraft pulp. Because of the unique structure of nano-order-scale interconnected fibrils and microfibrils greatly expanded in the surface area that characterizes MFC, it was possible to produce composites that exploit the extremely high strength of microfibrils. The Young’s modulus (E) and bending strength (σb) of composites using phenolic resin as binder achieved values up to 19 GPa and 370 MPa, respectively, with a density of 1.45 g/cm2, exhibiting outstanding mechanical properties for a plant-fiber-based composite.

Construction and performance of MEGAs low-mass, high-rate cylindrical MWPCs

NASA Astrophysics Data System (ADS)

Cooper, M. D.; Armijo, V.; Black, J. K.; Bolton, R. D.; Carius, S.; Espinoza, C.; Hart, G.; Hogan, G. E.; Gonzales, A.; Kroupa, M. A.; Mischke, R. E.; Sandoval, J.; Schilling, S.; Sena, J.; Suazo, G.; Whitehouse, D. A.; Wilkinson, C. A.; Stantz, K.; Szymanski, J. J.; Jui, C. C.; Gagliardi, C. A.; Tribble, R. E.; Tu, X.-L.; Fisk, R. J.; Koetke, D. D.; Manweiler, R. W.; Nord, P. M.; Stanislaus, S.; Piilonen, L. E.; Zhang, Y. D.

A design for extremely low mass, high-resolution multiwire proportional chambers (MWPC) was achieved by the MEGA collaboration in its experiment to search for the lepton family number violating decay μ→eγ. To extend the present branching ratio limit by over an order of magnitude, these MWPCs were operated in high particle fluxes. They showed minimal effects of aging, and evidenced spatial and energy resolutions for the orbiting positrons from muon decay which were consistent with our design parameters. The unique features of these chambers, their assembly into the MEGA positron spectrometer, and their performance during the experiment are described in this paper.

A general-purpose computer program for studying ultrasonic beam patterns generated with acoustic lenses

NASA Technical Reports Server (NTRS)

Roberti, Dino; Ludwig, Reinhold; Looft, Fred J.

1988-01-01

A 3-D computer model of a piston radiator with lenses for focusing and defocusing is presented. To achieve high-resolution imaging, the frequency of the transmitted and received ultrasound must be as high as 10 MHz. Current ultrasonic transducers produce an extremely narrow beam at these high frequencies and thus are not appropriate for imaging schemes such as synthetic-aperture focus techniques (SAFT). Consequently, a numerical analysis program has been developed to determine field intensity patterns that are radiated from ultrasonic transducers with lenses. Lens shapes are described and the field intensities are numerically predicted and compared with experimental results.

Operational characteristics of Wedge and Strip image readout systems

NASA Technical Reports Server (NTRS)

Siegmund, O. H. W.; Lampton, M.; Bixler, J.; Bowyer, S.; Malina, R. F.

1986-01-01

Application of the Wedge and Strip readout system in microchannel plate detectors for the Extreme Ultraviolet Explorer and FAUST space astronomy programs is discussed. Anode designs with high resolution (greater than 600 x 600 pixels) in imaging and spectroscopy applications have been developed. Extension of these designs to larger formats (100 mm) with higher resolution (3000 x 3000 pixels) are considered. It is shown that the resolution and imaging are highly stable, and that the flat field performance is essentially limited by photon statistics. Very high speed event response has also been achieved with output pulses having durations of less than 10 nanoseconds.

Extreme Events and Disaster Risk Reduction - a Future Earth KAN initiative

NASA Astrophysics Data System (ADS)

Frank, Dorothea; Reichstein, Markus

2017-04-01

The topic of Extreme Events in the context of global environmental change is both a scientifically challenging and exciting topic, and of very high societal relevance. The Future Earth Cluster initiative E3S organized in 2016 a cross-community/co-design workshop on Extreme Events and Environments from Climate to Society (http://www.e3s-future-earth.eu/index.php/ConferencesEvents/ConferencesAmpEvents). Based on the results, co-design research strategies and established network of the workshop, and previous activities, E3S is thriving to establish the basis for a longer-term research effort under the umbrella of Future Earth. These led to an initiative for a Future Earth Knowledge Action Network on Extreme Events and Disaster Risk Reduction. Example initial key question in this context include: What are meaningful indices to describe and quantify impact-relevant (e.g. climate) extremes? Which system properties yield resistance and resilience to extreme conditions? What are the key interactions between global urbanization processes, extreme events, and social and infrastructure vulnerability and resilience? The long-term goal of this KAN is to contribute to enhancing the resistance, resilience, and adaptive capacity of socio-ecological systems across spatial, temporal and institutional scales, in particular in the light of hazards affected by ongoing environmental change (e.g. climate change, global urbanization and land use/land cover change). This can be achieved by enhanced understanding, prediction, improved and open data and knowledge bases for detection and early warning decision making, and by new insights on natural and societal conditions and governance for resilience and adaptive capacity.

Utilization of Expert Knowledge in a Multi-Objective Hydrologic Model Automatic Calibration Process

NASA Astrophysics Data System (ADS)

Quebbeman, J.; Park, G. H.; Carney, S.; Day, G. N.; Micheletty, P. D.

2016-12-01

Spatially distributed continuous simulation hydrologic models have a large number of parameters for potential adjustment during the calibration process. Traditional manual calibration approaches of such a modeling system is extremely laborious, which has historically motivated the use of automatic calibration procedures. With a large selection of model parameters, achieving high degrees of objective space fitness - measured with typical metrics such as Nash-Sutcliffe, Kling-Gupta, RMSE, etc. - can easily be achieved using a range of evolutionary algorithms. A concern with this approach is the high degree of compensatory calibration, with many similarly performing solutions, and yet grossly varying parameter set solutions. To help alleviate this concern, and mimic manual calibration processes, expert knowledge is proposed for inclusion within the multi-objective functions, which evaluates the parameter decision space. As a result, Pareto solutions are identified with high degrees of fitness, but also create parameter sets that maintain and utilize available expert knowledge resulting in more realistic and consistent solutions. This process was tested using the joint SNOW-17 and Sacramento Soil Moisture Accounting method (SAC-SMA) within the Animas River basin in Colorado. Three different elevation zones, each with a range of parameters, resulted in over 35 model parameters simultaneously calibrated. As a result, high degrees of fitness were achieved, in addition to the development of more realistic and consistent parameter sets such as those typically achieved during manual calibration procedures.

Lower extremity work is associated with club head velocity during the golf swing in experienced golfers.

PubMed

McNally, M P; Yontz, N; Chaudhari, A M

2014-08-01

While the golf swing is a complex whole body movement requiring coordination of all joints to achieve maximum ball velocity, the kinetic contribution of the lower extremities to club head velocity has not been quantified, despite the perception that the legs are a primary source of power during the swing. Mechanical power at the hips, knees, and ankles was estimated during the downswing phase of a full swing with a driver using a passive optical motion capture system and 2 force plates for adult males across a range of age and self-reported skill levels. Total work by the lower extremities was calculated by integrating the powers of all 6 joints over the downswing. Regression analyses showed that total lower extremity work was a strong predictor of club head velocity (R=0.63). Secondary analyses showed different relationships to club head velocity in lead and trail leg lower extremity joints, but none of these were as predictive of club head velocity as the total work performed by the lower extremities. These results provide quantitative evidence that the lower body's kinetic contribution may be an important factor in achieving greater club head velocity, contributing to greater driving distance and overall golf performance. © Georg Thieme Verlag KG Stuttgart · New York.

Definitive Radiotherapy for Ewing Tumors of Extremities and Pelvis: Long-Term Disease Control, Limb Function, and Treatment Toxicity

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

Indelicato, Daniel J.; Keole, Sameer R.; Shahlaee, Amir H.

2008-11-01

Purpose: More than 70% of Ewing tumors occur in the extremities and pelvis. This study identified factors influencing local control and functional outcomes after management with definitive radiotherapy (RT). Patients and Methods: A total of 75 patients with a localized Ewing tumor of the extremity or pelvis were treated with definitive RT at the University of Florida between 1970 and 2006 (lower extremity tumors in 30, pelvic tumors in 26, and upper extremity tumors in 19). RT was performed on a once-daily (40%) or twice-daily (60%) basis. The median dose was 55.2 Gy in 1.8-Gy daily fractions or 55.0 Gymore » in 1.2-Gy twice-daily fractions. The median observed follow-up was 4.7 years. Functional outcome was assessed using the Toronto Extremity Salvage Score. Results: The 10-year actuarial overall survival, cause-specific survival, freedom from relapse, and local control rate was 48%, 48%, 42%, and 71%, respectively. Of the 72 patients, 3 required salvage amputation. Inferior cause-specific survival was associated with larger tumors (81% for tumors <8 cm vs. 39% for tumors {>=}8 cm, p <0.05). No patient characteristics or treatment variables were predictive of local failure. No fractures occurred in patients treated with hyperfractionation or with tumors of the distal extremities. Severe late complications were more frequently associated with use of <8-MV photons and fields encompassing the entire bone or hemipelvis. A significantly better Toronto Extremity Salvage Score was associated with a late-effect biologically effective dose of <91.7 Gy{sub 3}. Conclusions: Limb preservation was effectively achieved through definitive RT. Treating limited field sizes with hyperfractionated high-energy RT could minimize long-term complications and provides superior functional outcomes.« less

Extreme triple asymmetric (ETAS) epitaxial designs for increased efficiency at high powers in 9xx-nm diode lasers

NASA Astrophysics Data System (ADS)

Kaul, T.; Erbert, G.; Maaßdorf, A.; Martin, D.; Crump, P.

2018-02-01

Broad area lasers that are tailored to be most efficient at the highest achievable optical output power are sought by industry to decrease operation costs and improve system performance. Devices using Extreme-Double-ASymmetric (EDAS) epitaxial designs are promising candidates for improved efficiency at high optical output powers due to low series resistance, low optical loss and low carrier leakage. However, EDAS designs leverage ultra-thin p-side waveguides, meaning that the optical mode is shifted into the n-side waveguide, resulting in a low optical confinement in the active region, low gain and hence high threshold current, limiting peak performance. We introduce here explicit design considerations that enable EDAS-based devices to be developed with increased optical confinement in the active layer without changing the p-side layer thicknesses. Specifically, this is realized by introducing a third asymmetric component in the vicinity of the quantum well. We call this approach Extreme-Triple-ASymmetric (ETAS) design. A series of ETAS-based vertical designs were fabricated into broad area lasers that deliver up to 63% power conversion efficiency at 14 W CW optical output power from a 100 μm stripe laser, which corresponds to the operation point of a kW optical output power in a laser bar. The design process, the impact of structural changes on power saturation mechanisms and finally devices with improved performance will be presented.

Ultrahigh-speed phaselocked-loop type clock recovery circuit using a travelling-wave laser diode amplifier as a 50 GHz phase detector

NASA Astrophysics Data System (ADS)

Kawanishi, S.; Takara, H.; Saruwatari, M.; Kitoh, T.

1993-09-01

Successful operation of a phase-locked loop is demonstrated using a traveling-wave laser-diode amplifier as a 50 GHz phase detector. Optical gain modulation in the laser diode amplifier and an all-optical clock multiplication technique using a silica-based guided-wave optical circuit are used to achieve the extremely high-speed operation. Also discussed is the possibility of more than 100 GHz operation.

[A case of paracoccidioidomycosis with severe adrenal insufficiency].

PubMed

Yoshimura, Yukihiro; Tachikawa, Natsuo; Oosawa, Takayuki; Kosuge, Youko; Kamei, Katsuhiko

2012-05-01

Paracoccidioidomycosis (PCM) is the most common systemic fungal disease in central-south America, but is rare in Japan. We experiensed a case of PCM in a patient, who came from Bolivia and presented with mouth pain and reduced dietary intake but no fever. Adrenal insufficiency was diagnosed with extremely high serum adrenocorticotropic hormone (ACTH) and was resolved with hormone supplementation. The PCM was treated with trimethoprim-sulfamethoxazole which was switched to itraconazole and improvement was achieved.

High-volume optical vortex multiplexing and de-multiplexing for free-space optical communication.

PubMed

Wang, Zhongxi; Zhang, N; Yuan, X-C

2011-01-17

We report an approach to the increase of signal channels in free-space optical communication based on composed optical vortices (OVs). In the encoding process, conventional algorithm employed for the generation of collinearly superimposed OVs is combined with a genetic algorithm to achieve high-volume OV multiplexing. At the receiver end, a novel Dammann vortex grating is used to analyze the multihelix beams with a large number of OVs. We experimentally demonstrate a digitized system which is capable of transmitting and receiving 16 OV channels simultaneously. This system is expected to be compatible with a high-speed OV multiplexing technique, with potentials to extremely high-volume information density in OV communication.

Synovitis of the knee following a high-pressure injection injury with hydraulic oil.

PubMed

Noronha, Paulo A; Lomelino, Ronaldo O; Dinoá, Vanessa; Marchiori, Edson

2018-05-17

High-pressure injection injuries occur when equipment capable of achieving high pressure injects its contents into the human body. These injuries are largely occupational and may present as small entrance wounds with very few symptoms. However, they represent a surgical emergency, often requiring amputation. They characteristically involve the upper extremities, but other regions of the body may be injured. We present the case of a 26-year-old man who sustained a high-pressure injection injury with hydraulic oil to the knee and a literature review of this type of accident. To our knowledge, this report is the first to describe such an injury to the knee, with magnetic resonance imaging findings.

Teamwork as an Essential Component of High-Reliability Organizations

PubMed Central

Baker, David P; Day, Rachel; Salas, Eduardo

2006-01-01

Organizations are increasingly becoming dynamic and unstable. This evolution has given rise to greater reliance on teams and increased complexity in terms of team composition, skills required, and degree of risk involved. High-reliability organizations (HROs) are those that exist in such hazardous environments where the consequences of errors are high, but the occurrence of error is extremely low. In this article, we argue that teamwork is an essential component of achieving high reliability particularly in health care organizations. We describe the fundamental characteristics of teams, review strategies in team training, demonstrate the criticality of teamwork in HROs and finally, identify specific challenges the health care community must address to improve teamwork and enhance reliability. PMID:16898980

Extremely frequency-widened terahertz wave generation using Cherenkov-type radiation.

PubMed

Suizu, Koji; Koketsu, Kaoru; Shibuya, Takayuki; Tsutsui, Toshihiro; Akiba, Takuya; Kawase, Kodo

2009-04-13

Terahertz (THz) wave generation based on nonlinear frequency conversion is promising way for realizing a tunable monochromatic bright THz-wave source. Such a development of efficient and wide tunable THz-wave source depends on discovery of novel brilliant nonlinear crystal. Important factors of a nonlinear crystal for THz-wave generation are, 1. High nonlinearity and 2. Good transparency at THz frequency region. Unfortunately, many nonlinear crystals have strong absorption at THz frequency region. The fact limits efficient and wide tunable THz-wave generation. Here, we show that Cherenkov radiation with waveguide structure is an effective strategy for achieving efficient and extremely wide tunable THz-wave source. We fabricated MgO-doped lithium niobate slab waveguide with 3.8 microm of thickness and demonstrated difference frequency generation of THz-wave generation with Cherenkov phase matching. Extremely frequency-widened THz-wave generation, from 0.1 to 7.2 THz, without no structural dips successfully obtained. The tuning frequency range of waveguided Cherenkov radiation source was extremely widened compare to that of injection seeded-Terahertz Parametric Generator. The tuning range obtained in this work for THz-wave generation using lithium niobate crystal was the widest value in our knowledge. The highest THz-wave energy obtained was about 3.2 pJ, and the energy conversion efficiency was about 10(-5) %. The method can be easily applied for many conventional nonlinear crystals, results in realizing simple, reasonable, compact, high efficient and ultra broad band THz-wave sources.

FURTHER EVIDENCE ON THE “COSTS OF PRIVILEGE”: PERFECTIONISM IN HIGH-ACHIEVING YOUTH AT SOCIOECONOMIC EXTREMES

PubMed Central

LYMAN, EMILY L.; LUTHAR, SUNIYA S.

2015-01-01

This study involved two academically-gifted samples of 11th and 12th grade youth at the socioeconomic status (SES) extremes; one from an exclusive private, affluent school, and the other from a magnet school with low-income students. Negative and positive adjustment outcomes were examined in relation to multiple dimensions of perfectionism including perceived parental pressures to be perfect, personal perfectionistic self-presentation, and envy of peers. The low-income students showed some areas of relative vulnerability, but when large group differences were found, it was the affluent youth who were at a disadvantage, with substantially higher substance use and peer envy. Affluent girls seemed particularly vulnerable, with pronounced elevations in perfectionistic tendencies, peer envy, as well as body dissatisfaction. Examination of risk and protective processes showed that relationships with mothers were associated with students’ distress as well as positive adjustment. Additionally, findings showed links between (a) envy of peers and multiple outcomes (among high SES girls in particular), (b) dimensions of perfectionism in relation to internalizing symptoms, and (c) high extrinsic versus intrinsic values in relation to externalizing symptoms. PMID:26345229

Novel MRF fluid for ultra-low roughness optical surfaces

NASA Astrophysics Data System (ADS)

Dumas, Paul; McFee, Charles

2014-08-01

Over the past few years there have been an increasing number of applications calling for ultra-low roughness (ULR) surfaces. A critical demand has been driven by EUV optics, EUV photomasks, X-Ray, and high energy laser applications. Achieving ULR results on complex shapes like aspheres and X-Ray mirrors is extremely challenging with conventional polishing techniques. To achieve both tight figure and roughness specifications, substrates typically undergo iterative global and local polishing processes. Typically the local polishing process corrects the figure or flatness but cannot achieve the required surface roughness, whereas the global polishing process produces the required roughness but degrades the figure. Magnetorheological Finishing (MRF) is a local polishing technique based on a magnetically-sensitive fluid that removes material through a shearing mechanism with minimal normal load, thus removing sub-surface damage. The lowest surface roughness produced by current MRF is close to 3 Å RMS. A new ULR MR fluid uses a nano-based cerium as the abrasive in a proprietary aqueous solution, the combination of which reliably produces under 1.5Å RMS roughness on Fused Silica as measured by atomic force microscopy. In addition to the highly convergent figure correction achieved with MRF, we show results of our novel MR fluid achieving <1.5Å RMS roughness on fused silica and other materials.

The extreme ultraviolet spectroscope for planetary science, EXCEED

NASA Astrophysics Data System (ADS)

Yoshioka, K.; Murakami, G.; Yamazaki, A.; Tsuchiya, F.; Kagitani, M.; Sakanoi, T.; Kimura, T.; Uemizu, K.; Uji, K.; Yoshikawa, I.

2013-09-01

The extreme ultraviolet spectroscope EXtrem ultraviolet spetrosCope for ExosphEric Dynamics (EXCEED) on board the SPRINT-A mission will be launched in the summer of 2013 by the new Japanese solid propulsion rocket Epsilon as its first attempt, and it will orbit around the Earth with an orbital altitude of around 1000 km. EXCEED is dedicated to and optimized for observing the terrestrial planets Mercury, Venus and Mars, as well as Jupiter for several years. The instrument consists of an off axis parabolic entrance mirror, switchable slits with multiple filters and shapes, a toroidal grating, and a photon counting detector, together with a field of view guiding camera. The design goal is to achieve a large effective area but with high spatial and spectral resolution. In this paper, the performance of each optical component will be described as determined from the results of test evaluation of flight models. In addition, the results of the optical calibration of the overall instrument are also shown. As a result, the spectral resolution of EXCEED is found to be 0.3-0.5 nm Full Width at Half Maximum (FWHM) over the entire spectral band (52-148 nm) and the spatial resolution achieve was 10". The evaluated effective area is around 3 cm2. Based on these specifications, the possibility of EXCEED detecting atmospheric ions or atoms around Mercury, Venus, and Mars will be discussed. In addition, we estimate the spectra that might be detected from the Io plasma torus around Jupiter for various hypothetical plasma parameters.

A longitudinal study of ice hockey in boys aged 8--12.

PubMed

MacNab, R B

1979-03-01

A group of fifteen boys (experimental or competitive) were studied over a five year period of competitive ice hockey beginning at age 8. The subjects were members of a team which averaged 66 games per year, ranging from 50 at age 8 to 78 at age 12. In addition, they practiced twice a week with heavy stress on skating and individual puck handling skills. A second group of eleven boys (control or less competitive) were studied from age 10 to 12. The latter subjects played an average of 25 games per year and practiced once a week. All subjects were measured each year on skating and puck control skills, fitness-performance tests, grip strength, physical work capacity as well as height and weight. The results demonstrate learning curves for skating and puck control tests which, while typical in nature, show extremely high levels of achievement. Fitness-Performance, grip strength and physical work capacity levels of the competitive group are extremely high in comparison with data from other countries.

BELM: Bayesian extreme learning machine.

PubMed

Soria-Olivas, Emilio; Gómez-Sanchis, Juan; Martín, José D; Vila-Francés, Joan; Martínez, Marcelino; Magdalena, José R; Serrano, Antonio J

2011-03-01

The theory of extreme learning machine (ELM) has become very popular on the last few years. ELM is a new approach for learning the parameters of the hidden layers of a multilayer neural network (as the multilayer perceptron or the radial basis function neural network). Its main advantage is the lower computational cost, which is especially relevant when dealing with many patterns defined in a high-dimensional space. This brief proposes a bayesian approach to ELM, which presents some advantages over other approaches: it allows the introduction of a priori knowledge; obtains the confidence intervals (CIs) without the need of applying methods that are computationally intensive, e.g., bootstrap; and presents high generalization capabilities. Bayesian ELM is benchmarked against classical ELM in several artificial and real datasets that are widely used for the evaluation of machine learning algorithms. Achieved results show that the proposed approach produces a competitive accuracy with some additional advantages, namely, automatic production of CIs, reduction of probability of model overfitting, and use of a priori knowledge.

Implementation of micro-ball nanodiamond anvils for high-pressure studies above 6 Mbar

PubMed Central

Dubrovinsky, Leonid; Dubrovinskaia, Natalia; Prakapenka, Vitali B; Abakumov, Artem M

2012-01-01

Since invention of the diamond anvil cell technique in the late 1950s for studying materials at extreme conditions, the maximum static pressure generated so far at room temperature was reported to be about 400 GPa. Here we show that use of micro-semi-balls made of nanodiamond as second-stage anvils in conventional diamond anvil cells drastically extends the achievable pressure range in static compression experiments to above 600 GPa. Micro-anvils (10–50 μm in diameter) of superhard nanodiamond (with a grain size below ∼50 nm) were synthesized in a large volume press using a newly developed technique. In our pilot experiments on rhenium and gold we have studied the equation of state of rhenium at pressures up to 640 GPa and demonstrated the feasibility and crucial necessity of the in situ ultra high-pressure measurements for accurate determination of material properties at extreme conditions. PMID:23093199

From tunable core-shell nanoparticles to plasmonic drawbridges: Active control of nanoparticle optical properties

PubMed Central

Byers, Chad P.; Zhang, Hui; Swearer, Dayne F.; Yorulmaz, Mustafa; Hoener, Benjamin S.; Huang, Da; Hoggard, Anneli; Chang, Wei-Shun; Mulvaney, Paul; Ringe, Emilie; Halas, Naomi J.; Nordlander, Peter; Link, Stephan; Landes, Christy F.

2015-01-01

The optical properties of metallic nanoparticles are highly sensitive to interparticle distance, giving rise to dramatic but frequently irreversible color changes. By electrochemical modification of individual nanoparticles and nanoparticle pairs, we induced equally dramatic, yet reversible, changes in their optical properties. We achieved plasmon tuning by oxidation-reduction chemistry of Ag-AgCl shells on the surfaces of both individual and strongly coupled Au nanoparticle pairs, resulting in extreme but reversible changes in scattering line shape. We demonstrated reversible formation of the charge transfer plasmon mode by switching between capacitive and conductive electronic coupling mechanisms. Dynamic single-particle spectroelectrochemistry also gave an insight into the reaction kinetics and evolution of the charge transfer plasmon mode in an electrochemically tunable structure. Our study represents a highly useful approach to the precise tuning of the morphology of narrow interparticle gaps and will be of value for controlling and activating a range of properties such as extreme plasmon modulation, nanoscopic plasmon switching, and subnanometer tunable gap applications. PMID:26665175

Method for high-precision multi-layered thin film deposition for deep and extreme ultraviolet mirrors

DOEpatents

Ruffner, Judith Alison

1999-01-01

A method for coating (flat or non-flat) optical substrates with high-reflectivity multi-layer coatings for use at Deep Ultra-Violet ("DUV") and Extreme Ultra-Violet ("EUV") wavelengths. The method results in a product with minimum feature sizes of less than 0.10-.mu.m for the shortest wavelength (13.4-nm). The present invention employs a computer-based modeling and deposition method to enable lateral and vertical thickness control by scanning the position of the substrate with respect to the sputter target during deposition. The thickness profile of the sputter targets is modeled before deposition and then an appropriate scanning algorithm is implemented to produce any desired, radially-symmetric thickness profile. The present invention offers the ability to predict and achieve a wide range of thickness profiles on flat or figured substrates, i.e., account for 1/R.sup.2 factor in a model, and the ability to predict and accommodate changes in deposition rate as a result of plasma geometry, i.e., over figured substrates.

Extremely high boron tolerance in Puccinellia distans (Jacq.) Parl. related to root boron exclusion and a well-regulated antioxidant system.

PubMed

Hamurcu, Mehmet; Hakki, Erdogan E; Demiral Sert, Tijen; Özdemir, Canan; Minareci, Ersin; Avsaroglu, Zuhal Z; Gezgin, Sait; Ali Kayis, Seyit; Bell, Richard W

Recent studies indicate an extremely high level of tolerance to boron (B) toxicity in Puccinellia distans (Jacq.) Parl. but the mechanistic basis is not known. Puccinellia distans was exposed to B concentrations of up to 1000 mg B L-1 and root B uptake, growth parameters, B and N contents, H2O2 accumulation and ·OH-scavenging activity were measured. Antioxidant enzyme activities including superoxide dismutase (SOD), ascorbate peroxidase, catalase, peroxidase and glutathione reductase, and lipid peroxidation products were determined. B appears to be actively excluded from roots. Excess B supply caused structural deformations in roots and leaves, H2O2 accumulation and simultaneous up-regulation of the antioxidative system, which prevented lipid peroxidation even at the highest B concentrations. Thus, P. distans has an efficient root B-exclusion capability and, in addition, B tolerance in shoots is achieved by a well-regulated antioxidant defense system.

Preliminary study of the reliability of imaging charge coupled devices

NASA Technical Reports Server (NTRS)

Beall, J. R.; Borenstein, M. D.; Homan, R. A.; Johnson, D. L.; Wilson, D. D.; Young, V. F.

1978-01-01

Imaging CCDs are capable of low light level response and high signal-to-noise ratios. In space applications they offer the user the ability to achieve extremely high resolution imaging with minimum circuitry in the photo sensor array. This work relates the CCD121H Fairchild device to the fundamentals of CCDs and the representative technologies. Several failure modes are described, construction is analyzed and test results are reported. In addition, the relationship of the device reliability to packaging principles is analyzed and test data presented. Finally, a test program is defined for more general reliability evaluation of CCDs.

Near-Unity Absorption in van der Waals Semiconductors for Ultrathin Optoelectronics.

PubMed

Jariwala, Deep; Davoyan, Artur R; Tagliabue, Giulia; Sherrott, Michelle C; Wong, Joeson; Atwater, Harry A

2016-09-14

We demonstrate near-unity, broadband absorbing optoelectronic devices using sub-15 nm thick transition metal dichalcogenides (TMDCs) of molybdenum and tungsten as van der Waals semiconductor active layers. Specifically, we report that near-unity light absorption is possible in extremely thin (<15 nm) van der Waals semiconductor structures by coupling to strongly damped optical modes of semiconductor/metal heterostructures. We further fabricate Schottky junction devices using these highly absorbing heterostructures and characterize their optoelectronic performance. Our work addresses one of the key criteria to enable TMDCs as potential candidates to achieve high optoelectronic efficiency.

Ultrafast electron diffraction optimized for studying structural dynamics in thin films and monolayers

PubMed Central

Badali, D. S.; Gengler, R. Y. N.; Miller, R. J. D.

2016-01-01

A compact electron source specifically designed for time-resolved diffraction studies of free-standing thin films and monolayers is presented here. The sensitivity to thin samples is achieved by extending the established technique of ultrafast electron diffraction to the “medium” energy regime (1–10 kV). An extremely compact design, in combination with low bunch charges, allows for high quality diffraction in a lensless geometry. The measured and simulated characteristics of the experimental system reveal sub-picosecond temporal resolution, while demonstrating the ability to produce high quality diffraction patterns from atomically thin samples. PMID:27226978

Sensitivity of Hydrologic Extremes to Spatial Resolution of Meteorological Forcings: A Case Study of the Conterminous United States

NASA Astrophysics Data System (ADS)

Kao, S. C.; Naz, B. S.; Gangrade, S.; Ashfaq, M.; Rastogi, D.

2016-12-01

The magnitude and frequency of hydroclimate extremes are projected to increase in the conterminous United States (CONUS) with significant implications for future water resource planning and flood risk management. Nevertheless, apart from the change of natural environment, the choice of model spatial resolution could also artificially influence the features of simulated extremes. To better understand how the spatial resolution of meteorological forcings may affect hydroclimate projections, we test the runoff sensitivity using the Variable Infiltration Capacity (VIC) model that was calibrated for each CONUS 8-digit hydrologic unit (HUC8) at 1/24° ( 4km) grid resolution. The 1980-2012 gridded Daymet and PRISM meteorological observations are used to conduct the 1/24° resolution control simulation. Comparative simulations are achieved by smoothing the 1/24° forcing into 1/12° and 1/8° resolutions which are then used to drive the VIC model for the CONUS. In addition, we also test how the simulated high and low runoff conditions would react to change in precipitation (±10%) and temperature (+1°C). The results are further analyzed for various types of hydroclimate extremes across different watersheds in the CONUS. This work helps us understand the sensitivity of simulated runoff to different spatial resolutions of climate forcings and also its sensitivity to different watershed sizes and characteristics of extreme events in the future climate conditions.

Controlling Emergent Ferromagnetism at Complex Oxide Interfaces

NASA Astrophysics Data System (ADS)

Grutter, Alexander

The emergence of complex magnetic ground states at ABO3 perovskite heterostructure interfaces is among the most promising routes towards highly tunable nanoscale materials for spintronic device applications. Despite recent progress, isolating and controlling the underlying mechanisms behind these emergent properties remains a highly challenging materials physics problems. In particular, generating and tuning ferromagnetism localized at the interface of two non-ferromagnetic materials is of fundamental and technological interest. An ideal model system in which to study such effects is the CaRuO3/CaMnO3 interface, where the constituent materials are paramagnetic and antiferromagnetic in the bulk, respectively. Due to small fractional charge transfer to the CaMnO3 (0.07 e-/Mn) from the CaRuO3, the interfacial Mn ions are in a canted antiferromagnetic state. The delicate balance between antiferromagnetic superexchange and ferromagnetic double exchange results in a magnetic ground state which is extremely sensitive to perturbations. We exploit this sensitivity to achieve control of the magnetic interface, tipping the balance between ferromagnetic and antiferromagnetic interactions through octahedral connectivity modification. Such connectivity effects are typically tightly confined to interfaces, but by targeting a purely interfacial emergent magnetic system, we achieve drastic alterations to the magnetic ground state. These results demonstrate the extreme sensitivity of the magnetic state to the magnitude of the charge transfer, suggesting the potential for direct electric field control. We achieve such electric field control through direct back gating of a CaRuO3/CaMnO3 bilayer. Thus, the CaRuO3/CaMnO3 system provides new insight into how charge transfer, interfacial symmetry, and electric fields may be used to control ferromagnetism at the atomic scale.

Extreme creep resistance in a microstructurally stable nanocrystalline alloy

NASA Astrophysics Data System (ADS)

Darling, K. A.; Rajagopalan, M.; Komarasamy, M.; Bhatia, M. A.; Hornbuckle, B. C.; Mishra, R. S.; Solanki, K. N.

2016-09-01

Nanocrystalline metals, with a mean grain size of less than 100 nanometres, have greater room-temperature strength than their coarse-grained equivalents, in part owing to a large reduction in grain size. However, this high strength generally comes with substantial losses in other mechanical properties, such as creep resistance, which limits their practical utility; for example, creep rates in nanocrystalline copper are about four orders of magnitude higher than those in typical coarse-grained copper. The degradation of creep resistance in nanocrystalline materials is in part due to an increase in the volume fraction of grain boundaries, which lack long-range crystalline order and lead to processes such as diffusional creep, sliding and rotation. Here we show that nanocrystalline copper-tantalum alloys possess an unprecedented combination of properties: high strength combined with extremely high-temperature creep resistance, while maintaining mechanical and thermal stability. Precursory work on this family of immiscible alloys has previously highlighted their thermo-mechanical stability and strength, which has motivated their study under more extreme conditions, such as creep. We find a steady-state creep rate of less than 10-6 per second—six to eight orders of magnitude lower than most nanocrystalline metals—at various temperatures between 0.5 and 0.64 times the melting temperature of the matrix (1,356 kelvin) under an applied stress ranging from 0.85 per cent to 1.2 per cent of the shear modulus. The unusual combination of properties in our nanocrystalline alloy is achieved via a processing route that creates distinct nanoclusters of atoms that pin grain boundaries within the alloy. This pinning improves the kinetic stability of the grains by increasing the energy barrier for grain-boundary sliding and rotation and by inhibiting grain coarsening, under extremely long-term creep conditions. Our processing approach should enable the development of microstructurally stable structural alloys with high strength and creep resistance for various high-temperature applications, including in the aerospace, naval, civilian infrastructure and energy sectors.

Grain Yield and Water Use Efficiency in Extremely-Late Sown Winter Wheat Cultivars under Two Irrigation Regimes in the North China Plain.

PubMed

Wang, Bin; Zhang, Yinghua; Hao, Baozhen; Xu, Xuexin; Zhao, Zhigan; Wang, Zhimin; Xue, Qingwu

2016-01-01

Wheat production is threatened by water shortages and groundwater over-draft in the North China Plain (NCP). In recent years, winter wheat has been increasingly sown extremely late in early to mid-November after harvesting cotton or pepper. To improve water use efficiency (WUE) and guide the extremely late sowing practices, a 3-year field experiment was conducted under two irrigation regimes (W1, one-irrigation, 75 mm at jointing; W2, two-irrigation, 75 mm at jointing and 75 mm at anthesis) in 3 cultivars differing in spike size (HS4399, small spike; JM22, medium spike; WM8, large spike). Wheat was sown in early to mid-November at a high seeding rate of 800-850 seeds m(-2). Average yields of 7.42 t ha(-1) and WUE of 1.84 kg m(-3) were achieved with an average seasonal evapotranspiration (ET) of 404 mm. Compared with W2, wheat under W1 did not have yield penalty in 2 of 3 years, and had 7.9% lower seasonal ET and 7.5% higher WUE. The higher WUE and stable yield under W1 was associated with higher 1000-grain weight (TGW) and harvest index (HI). Among the 3 cultivars, JM22 had 5.9%-8.9% higher yield and 4.2%-9.3% higher WUE than WM8 and HS4399. The higher yield in JM22 was attributed mainly to higher HI and TGW due to increased post-anthesis biomass and deeper seasonal soil water extraction. In conclusion, one-irrigation with a medium-sized spike cultivar JM22 could be a useful strategy to maintain yield and high WUE in extremely late-sown winter wheat at a high seeding rate in the NCP.

Sequential Nonlinear Learning for Distributed Multiagent Systems via Extreme Learning Machines.

PubMed

Vanli, Nuri Denizcan; Sayin, Muhammed O; Delibalta, Ibrahim; Kozat, Suleyman Serdar

2017-03-01

We study online nonlinear learning over distributed multiagent systems, where each agent employs a single hidden layer feedforward neural network (SLFN) structure to sequentially minimize arbitrary loss functions. In particular, each agent trains its own SLFN using only the data that is revealed to itself. On the other hand, the aim of the multiagent system is to train the SLFN at each agent as well as the optimal centralized batch SLFN that has access to all the data, by exchanging information between neighboring agents. We address this problem by introducing a distributed subgradient-based extreme learning machine algorithm. The proposed algorithm provides guaranteed upper bounds on the performance of the SLFN at each agent and shows that each of these individual SLFNs asymptotically achieves the performance of the optimal centralized batch SLFN. Our performance guarantees explicitly distinguish the effects of data- and network-dependent parameters on the convergence rate of the proposed algorithm. The experimental results illustrate that the proposed algorithm achieves the oracle performance significantly faster than the state-of-the-art methods in the machine learning and signal processing literature. Hence, the proposed method is highly appealing for the applications involving big data.

ZERODUR iso-grid design of a 3m class light weighted mirror blank for the E-ELT M5

NASA Astrophysics Data System (ADS)

Jedamzik, Ralf; Leys, Antoine; Seibert, Volker; Westerhoff, Thomas

2014-07-01

The tip and tilt M5 mirror of the European Extremly Large Telescope (E-ELT) requires a demanding approach in light weighting. The approximately 3 m x 2.5 m elliptical plano mirror is specified to a weight of less than 500 kg with high Eigenfrequencies and low deformation under different inclination angles. In 2011 SCHOTT has presented a study to develop a design for the M5 mirror blank of the ESO E-ELT. The design presented was based on a radial square design to achieve the best compromise between performance and manufacturability. With the fabrication of a prototype section SCHOTT demonstrated its capability to manufacture the demanding features including pockets with 350 mm depth, thin walls and sloped pocket bottoms. Now 3 years later SCHOTT presents an iso-grid based design that is in accordance with the manufacturability progress that has been demonstrated in various ELZM (Extremely Lightweighted ZERODUR Mirrors) publications in the last two years. The achievements on the specified mechanical parameters are compared to the first approach from 2011. In this paper the results are presented and the performance parameters are discussed.

Experimental station for ultrafast extreme ultraviolet spectroscopy for non-equilibrium dynamics in warm dense matter

NASA Astrophysics Data System (ADS)

Lee, Jong-won; Geng, Xiaotao; Jung, Jae Hyung; Cho, Min Sang; Yang, Seong Hyeok; Jo, Jawon; Lee, Chang-lyoul; Cho, Byoung Ick; Kim, Dong-Eon

2018-07-01

Recent interest in highly excited matter generated by intense femtosecond laser pulses has led to experimental methods that directly investigate ultrafast non-equilibrium electronic and structural dynamics. We present a tabletop experimental station for the extreme ultraviolet (EUV) spectroscopy used to trace L-edge dynamics in warm dense aluminum with a temporal resolution of a hundred femtoseconds. The system consists of the EUV probe generation part via a high-order harmonic generation process of femtosecond laser pulses with atomic clusters, a beamline with high-throughput optics and a sample-refreshment system of nano-foils utilizing the full repetition rate of the probe, and a flat-field EUV spectrograph. With the accumulation of an order of a hundred shots, a clear observation of the change in the aluminum L-shell absorption was achieved with a temporal resolution of 90 fs in a 600-fs window. The signature of a non-equilibrium electron distribution over a 10-eV range and its evolution to a 1-eV Fermi distribution are observed. This demonstrates the capability of this apparatus to capture the non-equilibrium electron-hole dynamics in highly excited warm dense matter conditions.

Ultrashort pulse laser machining of metals and alloys

DOEpatents

Perry, Michael D.; Stuart, Brent C.

2003-09-16

The invention consists of a method for high precision machining (cutting, drilling, sculpting) of metals and alloys. By using pulses of a duration in the range of 10 femtoseconds to 100 picoseconds, extremely precise machining can be achieved with essentially no heat or shock affected zone. Because the pulses are so short, there is negligible thermal conduction beyond the region removed resulting in negligible thermal stress or shock to the material beyond approximately 0.1-1 micron (dependent upon the particular material) from the laser machined surface. Due to the short duration, the high intensity (>10.sup.12 W/cm.sup.2) associated with the interaction converts the material directly from the solid-state into an ionized plasma. Hydrodynamic expansion of the plasma eliminates the need for any ancillary techniques to remove material and produces extremely high quality machined surfaces with negligible redeposition either within the kerf or on the surface. Since there is negligible heating beyond the depth of material removed, the composition of the remaining material is unaffected by the laser machining process. This enables high precision machining of alloys and even pure metals with no change in grain structure.

Extreme Light Management in Mesoporous Wood Cellulose Paper for Optoelectronics.

PubMed

Zhu, Hongli; Fang, Zhiqiang; Wang, Zhu; Dai, Jiaqi; Yao, Yonggang; Shen, Fei; Preston, Colin; Wu, Wenxin; Peng, Peng; Jang, Nathaniel; Yu, Qingkai; Yu, Zongfu; Hu, Liangbing

2016-01-26

Wood fibers possess natural unique hierarchical and mesoporous structures that enable a variety of new applications beyond their traditional use. We dramatically modulate the propagation of light through random network of wood fibers. A highly transparent and clear paper with transmittance >90% and haze <1.0% applicable for high-definition displays is achieved. By altering the morphology of the same wood fibers that form the paper, highly transparent and hazy paper targeted for other applications such as solar cell and antiglare coating with transmittance >90% and haze >90% is also achieved. A thorough investigation of the relation between the mesoporous structure and the optical properties in transparent paper was conducted, including full-spectrum optical simulations. We demonstrate commercially competitive multitouch touch screen with clear paper as a replacement for plastic substrates, which shows excellent process compatibility and comparable device performance for commercial applications. Transparent cellulose paper with tunable optical properties is an emerging photonic material that will realize a range of much improved flexible electronics, photonics, and optoelectronics.

Terahertz-driven linear electron acceleration

PubMed Central

Nanni, Emilio A.; Huang, Wenqian R.; Hong, Kyung-Han; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Dwayne Miller, R. J.; Kärtner, Franz X.

2015-01-01

The cost, size and availability of electron accelerators are dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency accelerating structures operate with 30–50 MeV m−1 gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional radio-frequency structures. However, laser-driven wakefield accelerators require intense femtosecond sources and direct laser-driven accelerators suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here we demonstrate linear acceleration of electrons with keV energy gain using optically generated terahertz pulses. Terahertz-driven accelerating structures enable high-gradient electron/proton accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. These ultra-compact terahertz accelerators with extremely short electron bunches hold great potential to have a transformative impact for free electron lasers, linear colliders, ultrafast electron diffraction, X-ray science and medical therapy with X-rays and electron beams. PMID:26439410

Planar heterojunction perovskite solar cells with superior reproducibility

PubMed Central

Jeon, Ye-Jin; Lee, Sehyun; Kang, Rira; Kim, Jueng-Eun; Yeo, Jun-Seok; Lee, Seung-Hoon; Kim, Seok-Soon; Yun, Jin-Mun; Kim, Dong-Yu

2014-01-01

Perovskite solar cells (PeSCs) have been considered one of the competitive next generation power sources. To date, light-to-electric conversion efficiencies have rapidly increased to over 10%, and further improvements are expected. However, the poor device reproducibility of PeSCs ascribed to their inhomogeneously covered film morphology has hindered their practical application. Here, we demonstrate high-performance PeSCs with superior reproducibility by introducing small amounts of N-cyclohexyl-2-pyrrolidone (CHP) as a morphology controller into N,N-dimethylformamide (DMF). As a result, highly homogeneous film morphology, similar to that achieved by vacuum-deposition methods, as well as a high PCE of 10% and an extremely small performance deviation within 0.14% were achieved. This study represents a method for realizing efficient and reproducible planar heterojunction (PHJ) PeSCs through morphology control, taking a major step forward in the low-cost and rapid production of PeSCs by solving one of the biggest problems of PHJ perovskite photovoltaic technology through a facile method. PMID:25377945

Method of achieving the controlled release of thermonuclear energy

DOEpatents

Brueckner, Keith A.

1986-01-01

A method of achieving the controlled release of thermonuclear energy by illuminating a minute, solid density, hollow shell of a mixture of material such as deuterium and tritium with a high intensity, uniformly converging laser wave to effect an extremely rapid build-up of energy in inwardly traveling shock waves to implode the shell creating thermonuclear conditions causing a reaction of deuterons and tritons and a resultant high energy thermonuclear burn. Utilizing the resulting energy as a thermal source and to breed tritium or plutonium. The invention also contemplates a laser source wherein the flux level is increased with time to reduce the initial shock heating of fuel and provide maximum compression after implosion; and, in addition, computations and an equation are provided to enable the selection of a design having a high degree of stability and a dependable fusion performance by establishing a proper relationship between the laser energy input and the size and character of the selected material for the fusion capsule.

Photoexcited Graphene Metasurfaces: Significantly Enhanced and Tunable Magnetic Resonances

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

Fan, Yuancheng; Shen, Nian -Hai; Zhang, Fuli

Artificially constructed metamaterials or metasurfaces with tailored resonant elements provide a revolutionary platform for controlling light at the subwavelength scale. Switchable or frequency-agile meta-devices are highly desirable in achieving more flexible functionalities and have been explored extensively by incorporating various materials, which respond to external stimuli. Graphene, a two-dimensional material showing extraordinary physical properties, has been found very promising for tunable meta-devices. However, the high intrinsic loss of graphene severely obstructs us from achieving high-quality resonance in various graphene metamaterials and metasurfaces, and the loss compensation can be considered as a straightforward strategy to take further advantages of enhanced light–graphenemore » interactions. Here, we demonstrate that the photoexcited graphene, in which the quasi-Fermi energy of graphene changes corresponding to optical pumping, can boost the originally extremely weak magnetic resonance in a graphene split-ring metasurface, showing remarkable modulations in the transmission. In conclusion, our work pioneers the possibilities of optically pumped graphene metasurfaces for significant enhancement of resonances and feasible modulations.« less

Photoexcited Graphene Metasurfaces: Significantly Enhanced and Tunable Magnetic Resonances

DOE PAGES

Fan, Yuancheng; Shen, Nian -Hai; Zhang, Fuli; ...

2018-02-27

Artificially constructed metamaterials or metasurfaces with tailored resonant elements provide a revolutionary platform for controlling light at the subwavelength scale. Switchable or frequency-agile meta-devices are highly desirable in achieving more flexible functionalities and have been explored extensively by incorporating various materials, which respond to external stimuli. Graphene, a two-dimensional material showing extraordinary physical properties, has been found very promising for tunable meta-devices. However, the high intrinsic loss of graphene severely obstructs us from achieving high-quality resonance in various graphene metamaterials and metasurfaces, and the loss compensation can be considered as a straightforward strategy to take further advantages of enhanced light–graphenemore » interactions. Here, we demonstrate that the photoexcited graphene, in which the quasi-Fermi energy of graphene changes corresponding to optical pumping, can boost the originally extremely weak magnetic resonance in a graphene split-ring metasurface, showing remarkable modulations in the transmission. In conclusion, our work pioneers the possibilities of optically pumped graphene metasurfaces for significant enhancement of resonances and feasible modulations.« less

Terahertz-driven linear electron acceleration

DOE PAGES

Nanni, Emilio A.; Huang, Wenqian R.; Hong, Kyung-Han; ...

2015-10-06

The cost, size and availability of electron accelerators are dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency accelerating structures operate with 30–50 MeVm -1 gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional radio-frequency structures. However, laser-driven wakefield accelerators require intense femtosecond sources and direct laser-driven accelerators suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here we demonstrate linear acceleration of electrons with keV energy gain using optically generated terahertz pulses. Terahertz-driven accelerating structures enable high-gradient electron/protonmore » accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. As a result, these ultra-compact terahertz accelerators with extremely short electron bunches hold great potential to have a transformative impact for free electron lasers, linear colliders, ultrafast electron diffraction, X-ray science and medical therapy with X-rays and electron beams.« less

High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extreme Conditions

PubMed Central

Meier, Thomas; Haase, Jürgen

2014-01-01

Nuclear Magnetic Resonance (NMR) is one of the most important techniques for the study of condensed matter systems, their chemical structure, and their electronic properties. The application of high pressure enables one to synthesize new materials, but the response of known materials to high pressure is a very useful tool for studying their electronic structure and developing theories. For example, high-pressure synthesis might be at the origin of life; and understanding the behavior of small molecules under extreme pressure will tell us more about fundamental processes in our universe. It is no wonder that there has always been great interest in having NMR available at high pressures. Unfortunately, the desired pressures are often well into the Giga-Pascal (GPa) range and require special anvil cell devices where only very small, secluded volumes are available. This has restricted the use of NMR almost entirely in the past, and only recently, a new approach to high-sensitivity GPa NMR, which has a resonating micro-coil inside the sample chamber, was put forward. This approach enables us to achieve high sensitivity with experiments that bring the power of NMR to Giga-Pascal pressure condensed matter research. First applications, the detection of a topological electronic transition in ordinary aluminum metal and the closing of the pseudo-gap in high-temperature superconductivity, show the power of such an approach. Meanwhile, the range of achievable pressures was increased tremendously with a new generation of anvil cells (up to 10.1 GPa), that fit standard-bore NMR magnets. This approach might become a new, important tool for the investigation of many condensed matter systems, in chemistry, geochemistry, and in physics, since we can now watch structural changes with the eyes of a very versatile probe. PMID:25350694

High-sensitivity nuclear magnetic resonance at Giga-Pascal pressures: a new tool for probing electronic and chemical properties of condensed matter under extreme conditions.

PubMed

Meier, Thomas; Haase, Jürgen

2014-10-10

Nuclear Magnetic Resonance (NMR) is one of the most important techniques for the study of condensed matter systems, their chemical structure, and their electronic properties. The application of high pressure enables one to synthesize new materials, but the response of known materials to high pressure is a very useful tool for studying their electronic structure and developing theories. For example, high-pressure synthesis might be at the origin of life; and understanding the behavior of small molecules under extreme pressure will tell us more about fundamental processes in our universe. It is no wonder that there has always been great interest in having NMR available at high pressures. Unfortunately, the desired pressures are often well into the Giga-Pascal (GPa) range and require special anvil cell devices where only very small, secluded volumes are available. This has restricted the use of NMR almost entirely in the past, and only recently, a new approach to high-sensitivity GPa NMR, which has a resonating micro-coil inside the sample chamber, was put forward. This approach enables us to achieve high sensitivity with experiments that bring the power of NMR to Giga-Pascal pressure condensed matter research. First applications, the detection of a topological electronic transition in ordinary aluminum metal and the closing of the pseudo-gap in high-temperature superconductivity, show the power of such an approach. Meanwhile, the range of achievable pressures was increased tremendously with a new generation of anvil cells (up to 10.1 GPa), that fit standard-bore NMR magnets. This approach might become a new, important tool for the investigation of many condensed matter systems, in chemistry, geochemistry, and in physics, since we can now watch structural changes with the eyes of a very versatile probe.

Reliability of 3-Dimensional Measures of Single-Leg Drop Landing Across 3 Institutions: Implications for Multicenter Research for Secondary ACL-Injury Prevention.

PubMed

Myer, Gregory D; Bates, Nathaniel A; DiCesare, Christopher A; Barber Foss, Kim D; Thomas, Staci M; Wordeman, Samuel C; Sugimoto, Dai; Roewer, Benjamin D; Medina McKeon, Jennifer M; Di Stasi, Stephanie L; Noehren, Brian W; McNally, Michael; Ford, Kevin R; Kiefer, Adam W; Hewett, Timothy E

2015-05-01

Due to the limitations of single-center studies in achieving appropriate sampling with relatively rare disorders, multicenter collaborations have been proposed to achieve desired sampling levels. However, documented reliability of biomechanical data is necessary for multicenter injury-prevention studies and is currently unavailable. To measure the reliability of 3-dimensional (3D) biomechanical waveforms from kinetic and kinematic variables during a single-leg landing (SLL) performed at 3 separate testing facilities. Multicenter reliability study. 3 laboratories. 25 female junior varsity and varsity high school volleyball players who visited each facility over a 1-mo period. Subjects were instrumented with 43 reflective markers to record 3D motion as they performed SLLs. During the SLL the athlete balanced on 1 leg, dropped down off of a 31-cm-high box, and landed on the same leg. Kinematic and kinetic data from both legs were processed from 2 trials across the 3 laboratories. Coefficients of multiple correlations (CMC) were used to statistically compare each joint angle and moment waveform for the first 500 ms of landing. Average CMC for lower-extremity sagittal-plane motion was excellent between laboratories (hip .98, knee .95, ankle .99). Average CMC for lower-extremity frontal-plane motion was also excellent between laboratories (hip .98, knee .80, ankle .93). Kinetic waveforms were repeatable in each plane of rotation (3-center mean CMC ≥.71), while knee sagittal-plane moments were the most consistent measure across sites (3-center mean CMC ≥.94). CMC waveform comparisons were similar relative to the joint measured to previously published reports of between-sessions reliability of sagittal- and frontal-plane biomechanics performed at a single institution. Continued research is needed to further standardize technology and methods to help ensure that highly reliable results can be achieved with multicenter biomechanical screening models.

Catalytic Chemistry on Oxide Nanostructures

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

Asthagiri, Aravind; Dixon, David A.; Dohnalek, Zdenek

2016-05-29

Metal oxides represent one of the most important and widely employed materials in catalysis. Extreme variability of their chemistry provides a unique opportunity to tune their properties and to utilize them for the design of highly active and selective catalysts. For bulk oxides, this can be achieved by varying their stoichiometry, phase, exposed surface facets, defect, dopant densities and numerous other ways. Further, distinct properties from those of bulk oxides can be attained by restricting the oxide dimensionality and preparing them in the form of ultrathin films and nanoclusters as discussed throughout this book. In this chapter we focus onmore » demonstrating such unique catalytic properties brought by the oxide nanoscaling. In the highlighted studies planar models are carefully designed to achieve minimal dispersion of structural motifs and to attain detailed mechanistic understanding of targeted chemical transformations. Detailed level of morphological and structural characterization necessary to achieve this goal is accomplished by employing both high-resolution imaging via scanning probe methods and ensemble-averaged surface sensitive spectroscopic methods. Three prototypical examples illustrating different properties of nanoscaled oxides in different classes of reactions are selected.« less

Tuning nanoparticle size for enhanced functionality in perovskite thin films deposited by metal organic deposition

DOE PAGES

Miura, Masashi; Maiorov, Boris Alfredo; Sato, Michio; ...

2017-11-17

Because of pressing global environmental challenges, focus has been placed on materials for efficient energy use, and this has triggered the search for nanostructural modification methods to improve performance. Achieving a high density of tunable-sized second-phase nanoparticles while ensuring the matrix remains intact is a long-sought goal. In this paper, we present an effective, scalable method to achieve this goal using metal organic deposition in a perovskite system REBa 2Cu 3O 7 (rare earth (RE)) that enhances the superconducting properties to surpass that of previous achievements. We present two industrially compatible routes to tune the nanoparticle size by controlling diffusionmore » during the nanoparticle formation stage by selecting the second-phase material and modulating the precursor composition spatially. Combining these routes leads to an extremely high density (8 × 10 22 m -3) of small nanoparticles (7 nm) that increase critical currents and reduce detrimental effects of thermal fluctuations at all magnetic field strengths and temperatures. This method can be directly applied to other perovskite materials where nanoparticle addition is beneficial.« less

Tuning nanoparticle size for enhanced functionality in perovskite thin films deposited by metal organic deposition

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

Miura, Masashi; Maiorov, Boris Alfredo; Sato, Michio

Because of pressing global environmental challenges, focus has been placed on materials for efficient energy use, and this has triggered the search for nanostructural modification methods to improve performance. Achieving a high density of tunable-sized second-phase nanoparticles while ensuring the matrix remains intact is a long-sought goal. In this paper, we present an effective, scalable method to achieve this goal using metal organic deposition in a perovskite system REBa 2Cu 3O 7 (rare earth (RE)) that enhances the superconducting properties to surpass that of previous achievements. We present two industrially compatible routes to tune the nanoparticle size by controlling diffusionmore » during the nanoparticle formation stage by selecting the second-phase material and modulating the precursor composition spatially. Combining these routes leads to an extremely high density (8 × 10 22 m -3) of small nanoparticles (7 nm) that increase critical currents and reduce detrimental effects of thermal fluctuations at all magnetic field strengths and temperatures. This method can be directly applied to other perovskite materials where nanoparticle addition is beneficial.« less

Xenon gamma-ray detector for ecological applications

NASA Astrophysics Data System (ADS)

Novikov, Alexander S.; Ulin, Sergey E.; Chernysheva, Irina V.; Dmitrenko, Valery V.; Grachev, Victor M.; Petrenko, Denis V.; Shustov, Alexander E.; Uteshev, Ziyaetdin M.; Vlasik, Konstantin F.

2015-01-01

A description of the xenon detector (XD) for ecological applications is presented. The detector provides high energy resolution and is able to operate under extreme environmental conditions (wide temperature range and unfavorable acoustic action). Resistance to acoustic noise as well as improvement in energy resolution has been achieved by means of real-time digital pulse processing. Another important XD feature is the ionization chamber's thin wall with composite housing, which significantly decreases the mass of the device and expands its energy range, especially at low energies.

Novel portable press for synchrotron time-resolved 3-D micro-imagining under extreme conditions

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

Philippe, J.; Le Godec, Y., E-mail: yann.legodec@impmc.upmc.fr; Bergame, F.

Here we present the instrumental development to extend the synchrotron X-ray microtomography techniques to in situ studies under static compression (HP) or shear stress or the both conditions at high temperatures (HT). To achieve this, a new rotating tomography Paris-Edinburgh cell (rotoPEc) has been developed. This ultra-compact portable device, easily and successfully adapted to various multi-modal synchrotron experimental set-up at ESRF, SOLEIL and DIAMOND is explained in detail.

Current science requirements and planned implementation for the WFIRST-CGI Integral Field Spectrograph (IFS)

NASA Astrophysics Data System (ADS)

Mandell, Avi M.; Groff, Tyler D.; Gong, Qian; Rizzo, Maxime J.; Lupu, Roxana; Zimmerman, Neil T.; Saxena, Prabal; McElwain, Michael W.

2017-09-01

One of the key science goals of the Coronograph Instrument (CGI) on the WFIRST mission is to spectrally characterize the atmospheres of planets around other stars at extremely high contrast levels. To achieve this goal, the CGI instrument will include a integral field spectrograph (IFS) as one of the two science cameras. We present the current science requirements that pertain to the IFS design, describe how our design implementation flows from these requirements, and outline our current instrument design.

Current Science Requirements and Planned Implementation for the WFIRST-CGI Integral Field Spectrograph (IFS)

NASA Technical Reports Server (NTRS)

Mandell, Avi M.; Groff, Tyler D.; Gong, Qian; Rizzo, Maxime J.; Lupu, Roxana; Zimmerman, Neil T.; Saxena, Prabal; McElwain, Michael W.

2017-01-01

One of the key science goals of the Coronograph Instrument (CGI) on the WFIRST mission is to spectrally characterize the atmospheres of planets around other stars at extremely high contrast levels. To achieve this goal, the CGI Instrument will include a integral field spectrograph (IFS) as one of the two science cameras. We present the current science requirements that pertain to the IFS design, describe how our design implementation flows from these requirements, and outline our current instrument design.

Improved Density Control in the Pegasus Toroidal Experiment using Internal Fueling

NASA Astrophysics Data System (ADS)

Thome, K. E.; Bongard, M. W.; Cole, J. A.; Fonck, R. J.; Redd, A. J.; Winz, G. R.

2012-10-01

Routine density control up to and exceeding the Greenwald limit is critical to key Pegasus operational scenarios, including non-solenoidal startup plasmas created using single-point helicity injection and high β Ohmic plasmas. Confinement scalings suggest it is possible to achieve very high β plasmas in Pegasus by lowering the toroidal field and increasing ne/ng. In the past, Pegasus achieved β ˜ 20% in high recycling Ohmic plasmas without running into any operational boundaries.footnotetext Garstka, G.D. et al., Phys. Plasmas 10, 1705 (2003) However, recent Ohmic experiments have demonstrated that Pegasus currently operates in an extremely low-recycling regime with R < 0.8 and Zeff ˜ 1 using improved vacuum conditioning techniques, such as Ti gettering and cryogenic pumping. Hence, it is difficult to achieve ne/ng> 0.3 with these improved wall conditions. Presently, gas is injected using low-field side (LFS) modified PV-10 valves. To attain high ne/ng operation and coincidentally separate core plasma and local current source fueling two new gas fueling capabilities are under development. A centerstack capillary injection system has been commissioned and is undergoing initial tests. A LFS movable midplane needle gas injection system is currently under design and will reach r/a ˜ 0.25. Initial results from both systems will be presented.

Opto-mechanical design and development of a 460mm diffractive transmissive telescope

NASA Astrophysics Data System (ADS)

Qi, Bo; Wang, Lihua; Cui, Zhangang; Bian, Jiang; Xiang, Sihua; Ma, Haotong; Fan, Bin

2018-01-01

Using lightweight, replicated diffractive optics, we can construct extremely large aperture telescopes in space.The transmissive primary significantly reduces the sensitivities to out of plane motion as compared to reflective systems while reducing the manufacturing time and costs. This paper focuses on the design, fabrication and ground demonstration of a 460mm diffractive transmissive telescope the primary F/# is 6, optical field of view is 0.2° imagine bandwidth is 486nm 656nm.The design method of diffractive optical system was verified, the ability to capture a high-quality image using diffractive telescope collection optics was tested.The results show that the limit resolution is 94lp/mm, the diffractive system has a good imagine performance with broad bandwidths. This technology is particularly promising as a means to achieve extremely large optical primaries from compact, lightweight packages.

Granulation of fine powder

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

Chen, Ching-Fong

A mixture of fine powder including thorium oxide was converted to granulated powder by forming a first-green-body and heat treating the first-green-body at a high temperature to strengthen the first-green-body followed by granulation by crushing or milling the heat-treated first-green-body. The granulated powder was achieved by screening through a combination of sieves to achieve the desired granule size distribution. The granulated powder relies on the thermal bonding to maintain its shape and structure. The granulated powder contains no organic binder and can be stored in a radioactive or other extreme environment. The granulated powder was pressed and sintered to formmore » a dense compact with a higher density and more uniform pore size distribution.« less

Flexible MXene/Carbon Nanotube Composite Paper with High Volumetric Capacitance

DOE PAGES

Zhao, Meng-Qiang; Ren, Chang E.; Ling, Zheng; ...

2014-11-18

Electrochemical capacitors attract attention because of their high power densities and long cycle lives. Moreover, with increasing demand for portable and wearable electronics, recent research has focused primarily on improving the energy density per unit of volume of electrochemical capacitors. But, the volumetric capacitances of carbon-based electrodes is limited at around 60 F cm -3 for commercial devices, and at best in the range of 300 F cm -3 for low-density porous carbons (<0.5–1 g cm -3 ). Although extremely high capacitances of 1000–1500 F cm -3 can be achieved for hydrated ruthenium oxide, RuO 2 , its highmore » cost limits its wide-spread applications.« less

A new high-κ Al2O3 based metal-insulator-metal antifuse

NASA Astrophysics Data System (ADS)

Tian, Min; Zhong, Huicai; Li, Li; Wang, Zhigang

2018-06-01

In this paper, a new metal-insulator-metal (MIM) antifuse was fabricated with the high κ Al2O3 deposited by atomic layer deposition (ALD) as the dielectric. On this high κ antifuse structure, the very low on-state resistance was obtained under certain programming conditions. It is the first time that the antifuse on-state resistance has been found decreasing along with the increase of dielectric film thickness, which is attributed to a large current overshoot during breakdown. For the device with a dielectric thickness of 12 nm, very large overshoot current (∼60 mA) was observed and extremely low on-state resistance (∼10 Ω) was achieved.

Effective Detection of Mycotoxins by a Highly Luminescent Metal–Organic Framework

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

Hu, Zhichao; Lustig, William P.; Zhang, Jingming

In this paper, we designed and synthesized a new luminescent metal–organic framework (LMOF). LMOF-241 is highly porous and emits strong blue light with high efficiency. We demonstrate for the first time that very fast and extremely sensitive optical detection can be achieved, making use of the fluorescence quenching of an LMOF material. The compound is responsive to Aflatoxin B1 at parts per billion level, which makes it the best performing luminescence-based chemical sensor to date. We studied the electronic properties of LMOF-241 and selected mycotoxins, as well as the extent of mycotoxin–LMOF interactions, employing theoretical methods. Finally, possible electron andmore » energy transfer mechanisms are discussed.« less

Effective Detection of Mycotoxins by a Highly Luminescent Metal–Organic Framework

DOE PAGES

Hu, Zhichao; Lustig, William P.; Zhang, Jingming; ...

2015-12-11

In this paper, we designed and synthesized a new luminescent metal–organic framework (LMOF). LMOF-241 is highly porous and emits strong blue light with high efficiency. We demonstrate for the first time that very fast and extremely sensitive optical detection can be achieved, making use of the fluorescence quenching of an LMOF material. The compound is responsive to Aflatoxin B1 at parts per billion level, which makes it the best performing luminescence-based chemical sensor to date. We studied the electronic properties of LMOF-241 and selected mycotoxins, as well as the extent of mycotoxin–LMOF interactions, employing theoretical methods. Finally, possible electron andmore » energy transfer mechanisms are discussed.« less

A High Sensitivity Bio Photosensor for Detecting a Luciferase Bioluminescence

NASA Astrophysics Data System (ADS)

Kameda, Seiji; Moriyama, Yusuke; Noda, Kenichi; Iwata, Atsushi

A high sensitivity CMOS bio photosensor applicable to a bioluminescent assay was developed with a 0.18µm CMOS image sensor (CIS) process. The bio photosensor consisting of a photosensor and a PWM 20bit A/D converter achieved high sensitivity for detecting a extremely low bioluminescence due to a large photodiode area, a long exposure time and the other noise reduction techniques. The bio photosensor chip has a 2×4 sensor array on a 2.45×2.45mm2 die. Experimental results with the bioluminescence showed the chip can detect below 10-5lux luminescence at room temperature and the power consumption is 32µW.

A pulse-compression-ring circuit for high-efficiency electric propulsion.

PubMed

Owens, Thomas L

2008-03-01

A highly efficient, highly reliable pulsed-power system has been developed for use in high power, repetitively pulsed inductive plasma thrusters. The pulsed inductive thruster ejects plasma propellant at a high velocity using a Lorentz force developed through inductive coupling to the plasma. Having greatly increased propellant-utilization efficiency compared to chemical rockets, this type of electric propulsion system may one day propel spacecraft on long-duration deep-space missions. High system reliability and electrical efficiency are extremely important for these extended missions. In the prototype pulsed-power system described here, exceptional reliability is achieved using a pulse-compression circuit driven by both active solid-state switching and passive magnetic switching. High efficiency is achieved using a novel ring architecture that recovers unused energy in a pulse-compression system with minimal circuit loss after each impulse. As an added benefit, voltage reversal is eliminated in the ring topology, resulting in long lifetimes for energy-storage capacitors. System tests were performed using an adjustable inductive load at a voltage level of 3.3 kV, a peak current of 20 kA, and a current switching rate of 15 kA/micros.

Nanomaterials in Extreme Environments: Fundamentals and Applications Rostislav A. Andrievski and Arsen V. Khatchoyan

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

Devanathan, Ram

Nanomaterials in Extreme Environments Rostislav A. Andrievski and Arsen V. Khatchoyan Springer, 2016 106 pages, $99.00 (e-book $69.99) ISBN 978–3-319–25331–2 This slim volume is an extensive review of our current understanding of the response of nanostructured materials to extreme operating conditions, such as high temperature, flux of high energy neutrons, high pressure, mechanical stress, and oxidizing environments. The emphasis is on metallic materials, especially Cu alloys. Graphene-based materials, fullerenes, polymeric materials, nano-glasses and glass-ceramics are not covered by this review. The book has six chapters including an introduction and a brief conclusion. The introduction documents the growth of scientific interestmore » in nanostructured materials and stresses the need to study the behavior of nanomaterials under extreme conditions. This chapter also presents Herbert Gleiter’s classification of nanomaterials into twelve groups based on the shapes of the nanoscale features and chemical composition of the components of the nanostructure. The second chapter deals with the high temperature environment and the thermodynamics and kinetics of grain growth. The authors identify the lack of reliable thermodynamic data as a key limitation in this field. The discussion brings out the interplay of structural relaxation, redistribution of excess free volume, diffusion, and recrystallization in multicomponent nanostructures at elevated temperature. Chapter 3 focuses on the effects of ion and neutron irradiation on the structure and properties of nanomaterials. The authors do a good job of highlighting recent studies on the radiation tolerance of nanocrystalline oxides and rapid grain growth under irradiation. The material addresses both fission and fusion reactor applications. Chapter 4 reviews the effects of severe plastic deformation and cyclic loading on nanostructure formation and phase transformation. This chapter also explores the challenge of achieving high density while retaining nanostructural features during processing under extreme loads and high temperatures. Chapter 5 discusses the effects of corrosion on nanomaterials. The behavior of a variety of alloys and high melting point compounds in liquid media and high temperature oxidizing environments is reviewed. The concluding chapter identifies areas for further research. The book would have benefited from careful copy editing for use of the English language. Moreover, the excessive use of acronyms makes the text difficult to read. Each chapter ends with a section on the application of nanomaterials and a long list of references. The integration of theoretical approaches and simulation results with experimental data offers fresh insights into the behavior of nanomaterials. Overall, this book will serve as useful reference material for researchers interested in nanomaterials driven to extremes. Reviewer: Ram Devanathan is Technical Group Manager of Reactor Materials and Mechanical Design, Pacific Northwest National Laboratory, USA.« less

Simple Motor Control Concept Results High Efficiency at High Velocities

NASA Astrophysics Data System (ADS)

Starin, Scott; Engel, Chris

2013-09-01

The need for high velocity motors in space applications for reaction wheels and detectors has stressed the limits of Brushless Permanent Magnet Motors (BPMM). Due to inherent hysteresis core losses, conventional BPMMs try to balance the need for torque verses hysteresis losses. Cong-less motors have significantly less hysteresis losses but suffer from lower efficiencies. Additionally, the inherent low inductance in cog-less motors result in high ripple currents or high switching frequencies, which lowers overall efficiency and increases performance demands on the control electronics.However, using a somewhat forgotten but fully qualified technology of Isotropic Magnet Motors (IMM), extremely high velocities may be achieved at low power input using conventional drive electronics. This paper will discuss the trade study efforts and empirical test data on a 34,000 RPM IMM.

Modal analysis of the ultrahigh finesse Haroche QED cavity

NASA Astrophysics Data System (ADS)

Marsic, Nicolas; De Gersem, Herbert; Demésy, Guillaume; Nicolet, André; Geuzaine, Christophe

2018-04-01

In this paper, we study a high-order finite element approach to simulate an ultrahigh finesse Fabry–Pérot superconducting open resonator for cavity quantum electrodynamics. Because of its high quality factor, finding a numerically converged value of the damping time requires an extremely high spatial resolution. Therefore, the use of high-order simulation techniques appears appropriate. This paper considers idealized mirrors (no surface roughness and perfect geometry, just to cite a few hypotheses), and shows that under these assumptions, a damping time much higher than what is available in experimental measurements could be achieved. In addition, this work shows that both high-order discretizations of the governing equations and high-order representations of the curved geometry are mandatory for the computation of the damping time of such cavities.

Addressing the mischaracterization of extreme rainfall in regional climate model simulations - A synoptic pattern based bias correction approach

NASA Astrophysics Data System (ADS)

Li, Jingwan; Sharma, Ashish; Evans, Jason; Johnson, Fiona

2018-01-01

Addressing systematic biases in regional climate model simulations of extreme rainfall is a necessary first step before assessing changes in future rainfall extremes. Commonly used bias correction methods are designed to match statistics of the overall simulated rainfall with observations. This assumes that change in the mix of different types of extreme rainfall events (i.e. convective and non-convective) in a warmer climate is of little relevance in the estimation of overall change, an assumption that is not supported by empirical or physical evidence. This study proposes an alternative approach to account for the potential change of alternate rainfall types, characterized here by synoptic weather patterns (SPs) using self-organizing maps classification. The objective of this study is to evaluate the added influence of SPs on the bias correction, which is achieved by comparing the corrected distribution of future extreme rainfall with that using conventional quantile mapping. A comprehensive synthetic experiment is first defined to investigate the conditions under which the additional information of SPs makes a significant difference to the bias correction. Using over 600,000 synthetic cases, statistically significant differences are found to be present in 46% cases. This is followed by a case study over the Sydney region using a high-resolution run of the Weather Research and Forecasting (WRF) regional climate model, which indicates a small change in the proportions of the SPs and a statistically significant change in the extreme rainfall over the region, although the differences between the changes obtained from the two bias correction methods are not statistically significant.

Ultrasound-guided supraclavicular block: outcome of 510 consecutive cases.

PubMed

Perlas, Anahi; Lobo, Giovanni; Lo, Nick; Brull, Richard; Chan, Vincent W S; Karkhanis, Reena

2009-01-01

Supraclavicular brachial plexus block provides consistently effective anesthesia to the upper extremity. However, traditional nerve localization techniques may be associated with a high risk of pneumothorax. In the present study, we report block success and clinical outcome data from 510 consecutive patients who received an ultrasound-guided supraclavicular block for upper extremity surgery. After institutional review board approval, the outcome of 510 consecutive patients who received an ultrasound-guided supraclavicular block for upper extremity surgery was reviewed. Real-time ultrasound guidance was used with a high-frequency linear probe. The neurovascular structures were imaged on short axis, and the needle was inserted using an in-plane technique with either a medial-to-lateral or lateral-to-medial orientation. Five hundred ten ultrasound-guided supraclavicular blocks were performed (50 inpatients, 460 outpatients) by 47 different operators at different levels of training over a 24-month period. Successful surgical anesthesia was achieved in 94.6% of patients after a single attempt; 2.8% required local anesthetic supplementation of a single peripheral nerve territory; and 2.6% received an unplanned general anesthetic. No cases of clinically symptomatic pneumothorax developed. Complications included symptomatic hemidiaphragmatic paresis (1%), Horner syndrome (1%), unintended vascular punctures (0.4%), and transient sensory deficits (0.4%). Ultrasound-guided supraclavicular block is associated with a high rate of successful surgical anesthesia and a low rate of complications and thus may be a safe alternative for both inpatients and outpatients. Severe underlying respiratory disease and coagulopathy should remain a contraindication for this brachial plexus approach.

Performance of the Micropower Voltage Reference ADR3430 Under Extreme Temperatures

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Hammoud, Ahmad

2011-01-01

Electronic systems designed for use in space exploration systems are expected to be exposed to harsh temperatures. For example, operation at cryogenic temperatures is anticipated in space missions such as polar craters of the moon (-223 C), James Webb Space Telescope (-236 C), Mars (-140 C), Europa (-223 C), Titan (-178 C), and other deep space probes away from the sun. Similarly, rovers and landers on the lunar surface, and deep space probes intended for the exploration of Venus are expected to encounter high temperature extremes. Electronics capable of operation under extreme temperatures would not only meet the requirements of future spacebased systems, but would also contribute to enhancing efficiency and improving reliability of these systems through the elimination of the thermal control elements that present electronics need for proper operation under the harsh environment of space. In this work, the performance of a micropower, high accuracy voltage reference was evaluated over a wide temperature range. The Analog Devices ADR3430 chip uses a patented voltage reference architecture to achieve high accuracy, low temperature coefficient, and low noise in a CMOS process [1]. The device combines two voltages of opposite temperature coefficients to create an output voltage that is almost independent of ambient temperature. It is rated for the industrial temperature range of -40 C to +125 C, and is ideal for use in low power precision data acquisition systems and in battery-powered devices. Table 1 shows some of the manufacturer s device specifications.

Extremes of Survival Achieved by the Radiophile Deinococcus Radiodurans: A Model for Microbial Life on Mars

NASA Technical Reports Server (NTRS)

Daly, M.; Sridhar, R.; Richmond, R.

1999-01-01

Deinococcus radiodurans is an extremophile in more than one defined way. First it is extreme in its resistance to freeze drying. Second it is probably uniquely extreme on Earth in its resistance to ionizing radiation. The polyextremophilic capacity of D. radiodurans will be considered. The selection pressures on Mars will then be considered in relation to D. radiodurans in order to support a hypothesis that if microbial life exists on Mars, then it likely includes polyextremophiles.

Uncooled IR imager with 5-mK NEDT

NASA Astrophysics Data System (ADS)

Amantea, Robert; Knoedler, C. M.; Pantuso, Francis P.; Patel, Vipulkumar; Sauer, Donald J.; Tower, John R.

1997-08-01

The bi-material concept for room-temperature infrared imaging has the potential of reaching an NE(Delta) T approaching the theoretical limit because of its high responsivity and low noise. The approach, which is 100% compatible with silicon IC foundry processing, utilizes a novel combination of surface micromachining and conventional integrated circuits to produce a bimaterial thermally sensitive element that controls the position of a capacitive plate coupled to the input of a low noise MOS amplifier. This approach can achieve the high sensitivity, the low weight, and the low cost necessary for equipment such as helmet mounted IR viewers and IR rifle sights. The pixel design has the following benefits: (1) an order of magnitude improvement in NE(Delta) T due to extremely high sensitivity and low noise, (2) low cost due to 100% silicon IC compatibility, (3) high image quality and increased yield due to ability to do offset and sensitivity corrections on the imager, pixel-by-pixel; (4) no cryogenic cooler and no high vacuum processing; and (5) commercial applications such as law enforcement, home security, and transportation safety. Two designs are presented. One is a 50 micrometer pixel using silicon nitride as the thermal isolation element that can achieve 5 mK NE(Delta) T; the other is a 29 micrometer pixel using silicon carbide that provides much higher thermal isolation and can achieve 10 mK NE(Delta) T.

Differential Resonant Ring YIG Tuned Oscillator

NASA Technical Reports Server (NTRS)

Parrott, Ronald A.

2010-01-01

A differential SiGe oscillator circuit uses a resonant ring-oscillator topology in order to electronically tune the oscillator over multi-octave bandwidths. The oscillator s tuning is extremely linear, because the oscillator s frequency depends on the magnetic tuning of a YIG sphere, whose resonant frequency is equal to a fundamental constant times the DC magnetic field. This extremely simple circuit topology uses two coupling loops connecting a differential pair of SiGe bipolar transistors into a feedback configuration using a YIG tuned filter creating a closed-loop ring oscillator. SiGe device technology is used for this oscillator in order to keep the transistor s 1/f noise to an absolute minimum in order to achieve minimum RF phase noise. The single-end resonant ring oscillator currently has an advantage in fewer parts, but when the oscillation frequency is greater than 16 GHz, the package s parasitic behavior couples energy to the sphere and causes holes and poor phase noise performance. This is because the coupling to the YIG is extremely low, so that the oscillator operates at near the unloaded Q. With the differential resonant ring oscillator, the oscillation currents are just in the YIG coupling mechanisms. The phase noise is even better, and the physical size can be reduced to permit monolithic microwave integrated circuit oscillators. This invention is a YIG tuned oscillator circuit making use of a differential topology to simultaneously achieve an extremely broadband electronic tuning range and ultra-low phase noise. As a natural result of its differential circuit topology, all reactive elements, such as tuning stubs, which limit tuning bandwidth by contributing excessive open loop phase shift, have been eliminated. The differential oscillator s open-loop phase shift is associated with completely non-dispersive circuit elements such as the physical angle of the coupling loops, a differential loop crossover, and the high-frequency phase shift of the n-p-n transistors. At the input of the oscillator s feedback loop is a pair of differentially connected n-p-n SiGe transistors that provides extremely high gain, and because they are bulk-effect devices, extremely low 1/f noise (leading to ultralow RF phase noise). The 1/f corner frequency for n-p-n SiGe transistors is approximately 500 Hz. The RF energy from the transistor s collector output is connected directly to the top-coupling loop (the excitation loop) of a single-sphere YIG tuned filter. A uniform magnetic field to bias the YIG must be at a right angle to any vector associated with an RF current in a coupling loop in order for the precession to interact with the RF currents.

Treatment modifications in tumour necrosis factor-α (TNF)-based isolated limb perfusion in patients with advanced extremity soft tissue sarcomas.

PubMed

Deroose, Jan P; Grünhagen, Dirk J; de Wilt, Johannes H W; Eggermont, Alexander M M; Verhoef, Cornelis

2015-02-01

Tumour necrosis factor-α (TNF) and melphalan based isolated limb perfusion (TM-ILP) is an attractive treatment option for advanced extremity soft tissue sarcomas (STS). This study reports on a 20-year single centre experience and discusses the evolution and changes in methodology since the introduction of TNF in ILP. We performed 306 TM-ILPs in 275 patients with extremity STS. All patients were candidates for amputation or mutilating surgery in order to achieve local control. Clinical response evaluation consisted of clinical examination and magnetic resonance imaging. To evaluate the importance of TNF-dose, treatment results of two periods (1991-2003 high dose (3-4 mg) TNF; 2003-2012 reduced dose (1-2mg) TNF) were compared. During the study period, more femoral perfusions were done instead of iliac perfusions. Reduction of TNF dose and reduction of total ILP time did not lead to different clinical response rates (70% and 69% for periods 1 and 2 respectively) or different local recurrence rates, but was associated with less local toxicity (23% and 14% for periods 1 and 2 respectively). Hospital stay was significantly reduced during the study period. There was an improved pathological response in the high dose TNF group without consequences for clinical outcome. TM-ILP remains a very effective treatment modality for limb threatening extremity STS. Moreover, reduction of dose and the growing experience in ILP led to less local toxicity and shorter hospital stay. Copyright © 2014 Elsevier Ltd. All rights reserved.

Functional Supramolecular Polymers*

PubMed Central

Aida, T.; Meijer, E.W.; Stupp, S.I.

2012-01-01

Supramolecular polymers can be random and entangled coils with the mechanical properties of plastics and elastomers, but with great capacity for processability, recycling, and self-healing due to their reversible monomer-to-polymer transitions. At the other extreme, supramolecular polymers can be formed by self-assembly among designed subunits to yield shape-persistent and highly ordered filaments. The use of strong and directional interactions among molecular subunits can achieve not only rich dynamic behavior but also high degrees of internal order that are not known in ordinary polymers. They can resemble, for example, the ordered and dynamic one-dimensional supramolecular assemblies of the cell cytoskeleton, and possess useful biological and electronic functions. PMID:22344437

The space shuttle program from challenge to achievement: Space exploration rolling on tires

NASA Technical Reports Server (NTRS)

Felder, G. L.

1985-01-01

The Space Shuttle Transportation System is the first space program to employ the pneumatic tire as a part of space exploration. For aircraft tires, this program establishes new expectations as to what constitutes acceptable performance within a set of tough environmental and operational conditions. Tire design, stresses the usual low weight, high load, high speed, and excellent air retention features but at extremes well outside industry standards. Tires will continue to be an integral part of the Shuttle's landing phase in the immediate future since they afford a unique combination of directional control, braking traction, flotation and shock absorption not available by other systems.

Wearable, wireless gas sensors using highly stretchable and transparent structures of nanowires and graphene.

PubMed

Park, Jihun; Kim, Joohee; Kim, Kukjoo; Kim, So-Yun; Cheong, Woon Hyung; Park, Kyeongmin; Song, Joo Hyeb; Namgoong, GyeongHo; Kim, Jae Joon; Heo, Jaeyeong; Bien, Franklin; Park, Jang-Ung

2016-05-19

Herein, we report the fabrication of a highly stretchable, transparent gas sensor based on silver nanowire-graphene hybrid nanostructures. Due to its superb mechanical and optical characteristics, the fabricated sensor demonstrates outstanding and stable performances even under extreme mechanical deformation (stable until 20% of strain). The integration of a Bluetooth system or an inductive antenna enables the wireless operation of the sensor. In addition, the mechanical robustness of the materials allows the device to be transferred onto various nonplanar substrates, including a watch, a bicycle light, and the leaves of live plants, thereby achieving next-generation sensing electronics for the 'Internet of Things' area.

Cryogenic, low-noise high electron mobility transistor amplifiers for the Deep Space Network

NASA Technical Reports Server (NTRS)

Bautista, J. J.

1993-01-01

The rapid advances recently achieved by cryogenically cooled high electron mobility transistor (HEMT) low-noise amplifiers (LNA's) in the 1- to 10-GHz range are making them extremely competitive with maser amplifiers. In order to address future spacecraft navigation, telemetry, radar, and radio science needs, the Deep Space Network is investing both maser and HEMT amplifiers for its Ka-band (32-GHz) downlink capability. This article describes the current state cryogenic HEMT LNA development at Ka-band for the DSN. Noise performance results at S-band (2.3 GHz) and X-band (8.5 GHz) for HEMT's and masers are included for completeness.

Generalized extreme gust wind speeds distributions

USGS Publications Warehouse

Cheng, E.; Yeung, C.

2002-01-01

Since summer 1996, the US wind engineers are using the extreme gust (or 3-s gust) as the basic wind speed to quantify the destruction of extreme winds. In order to better understand these destructive wind forces, it is important to know the appropriate representations of these extreme gust wind speeds. Therefore, the purpose of this study is to determine the most suitable extreme value distributions for the annual extreme gust wind speeds recorded in large selected areas. To achieve this objective, we are using the generalized Pareto distribution as the diagnostic tool for determining the types of extreme gust wind speed distributions. The three-parameter generalized extreme value distribution function is, thus, reduced to either Type I Gumbel, Type II Frechet or Type III reverse Weibull distribution function for the annual extreme gust wind speeds recorded at a specific site.With the considerations of the quality and homogeneity of gust wind data collected at more than 750 weather stations throughout the United States, annual extreme gust wind speeds at selected 143 stations in the contiguous United States were used in the study. ?? 2002 Elsevier Science Ltd. All rights reserved.

Optimal ventilatory patterns in periodic breathing.

PubMed

Ghazanshahi, S D; Khoo, M C

1993-01-01

The goal of this study was to determine whether periodic breathing (PB), which is highly prevalent during sleep at high altitudes, imposes physiological penalties on the respiratory system in the absence of any accompanying disease. Using a computer model of respiratory gas exchange, we compared the effects of a variety of PB patterns on the chemical and mechanical costs of breathing to those resulting from regular tidal breathing. Although PB produced considerable fluctuation in arterial blood gas tensions, for the same cycle-averaged ventilation, higher arterial oxygen saturation and lower arterial carbon dioxide levels were achieved. This result can be explained by the fact that the combination of large breaths and apnea in PB leads to a substantial reduction in dead space ventilation. At the same time, the savings in mechanical cost achieved by the respiratory muscles during apnea partially offset the increase during the breathing phase. Consequently, the "pressure cost," a criterion based on mean inspiratory pressure, was elevated only slightly, although the average work rate of breathing increased significantly. We found that, at extreme altitudes, PB patterns with clusters of 2 to 4 large breaths that alternate with apnea produce the highest arterial oxygenation levels and lowest pressure costs. The common occurrence of PB patterns with closely similar features has been reported in sleeping healthy sojourners at extreme altitudes. Taken together, these findings suggest that PB favors a reduction in the oxygen demands of the respiratory muscles and therefore may not be as detrimental as it is generally believed to be.

Impulsive personality and the ability to resist immediate reward: an fMRI study examining interindividual differences in the neural mechanisms underlying self-control.

PubMed

Diekhof, Esther Kristina; Nerenberg, Lesly; Falkai, Peter; Dechent, Peter; Baudewig, Jürgen; Gruber, Oliver

2012-12-01

The ability to resist immediate rewards is crucial for lifetime success and individual well-being. Using functional magnetic resonance imaging, we assessed the association between trait impulsivity and the neural underpinnings of the ability to control immediate reward desiring. Low and high extreme impulsivity groups were compared with regard to their behavioral performance and brain activation in situations, in which they had to forego immediate rewards with varying value to achieve a superordinate long-term goal. We found that highly impulsive (HI) individuals, who successfully compensated for their lack in behavioral self-control, engaged two complementary brain mechanisms when choosing actions in favor of a long-term goal, but at the expense of an immediate reward. First, self-controlled decisions led to a general attenuation of reward-related activation in the nucleus accumbens, which was accompanied by an increased inverse connectivity with the anteroventral prefrontal cortex. Second, HI subjects controlled their desire for increasingly valuable, but suboptimal rewards through a linear reduction of activation in the ventromedial prefrontal cortex (VMPFC). This was achieved by an increased inverse coupling between the VMPFC and the ventral striatum. Importantly, the neural mechanisms observed in the HI group differed from those in extremely controlled individuals, despite similar behavioral performance. Collectively, these results suggest trait-specific neural mechanisms that allow HI individuals to control their desire for immediate reward. Copyright © 2011 Wiley Periodicals, Inc.

High-Pressure Design of Advanced BN-Based Materials.

PubMed

Kurakevych, Oleksandr O; Solozhenko, Vladimir L

2016-10-20

The aim of the present review is to highlight the state of the art in high-pressure design of new advanced materials based on boron nitride. Recent experimental achievements on the governing phase transformation, nanostructuring and chemical synthesis in the systems containing boron nitride at high pressures and high temperatures are presented. All these developments allowed discovering new materials, e.g., ultrahard nanocrystalline cubic boron nitride (nano-cBN) with hardness comparable to diamond, and superhard boron subnitride B 13 N₂. Thermodynamic and kinetic aspects of high-pressure synthesis are described based on the data obtained by in situ and ex situ methods. Mechanical and thermal properties (hardness, thermoelastic equations of state, etc.) are discussed. New synthetic perspectives, combining both soft chemistry and extreme pressure-temperature conditions are considered.

[Multi-temporal scale analysis of impacts of extreme high temperature on net carbon uptake in subtropical coniferous plantation.

PubMed

Zhang, Mi; Wen, Xue Fa; Zhang, Lei Ming; Wang, Hui Min; Guo, Yi Wen; Yu, Gui Rui

2018-02-01

Extreme high temperature is one of important extreme weathers that impact forest ecosystem carbon cycle. In this study, applying CO 2 flux and routine meteorological data measured during 2003-2012, we examined the impacts of extreme high temperature and extreme high temperature event on net carbon uptake of subtropical coniferous plantation in Qianyanzhou. Combining with wavelet analysis, we analyzed environmental controls on net carbon uptake at different temporal scales, when the extreme high temperature and extreme high temperature event happened. The results showed that mean daily cumulative NEE decreased by 51% in the days with daily maximum air temperature range between 35 ℃ and 40 ℃, compared with that in the days with the range between 30 ℃ and 34 ℃. The effects of the extreme high temperature and extreme high temperature event on monthly NEE and annual NEE related to the strength and duration of extreme high tempe-rature event. In 2003, when strong extreme high temperature event happened, the sum of monthly cumulative NEE in July and August was only -11.64 g C·m -2 ·(2 month) -1 . The value decreased by 90%, compared with multi-year average value. At the same time, the relative variation of annual NEE reached -6.7%. In July and August, when the extreme high temperature and extreme high temperature event occurred, air temperature (T a ) and vapor press deficit (VPD) were the dominant controller for the daily variation of NEE. The coherency between NEE T a and NEE VPD was 0.97 and 0.95, respectively. At 8-, 16-, and 32-day periods, T a , VPD, soil water content at 5 cm depth (SWC), and precipitation (P) controlled NEE. The coherency between NEE SWC and NEE P was higher than 0.8 at monthly scale. The results indicated that atmospheric water deficit impacted NEE at short temporal scale, when the extreme high temperature and extreme high temperature event occurred, both of atmospheric water deficit and soil drought stress impacted NEE at long temporal scales in this ecosystem.

Microsurgery within reconstructive surgery of extremities.

PubMed

Pheradze, I; Pheradze, T; Tsilosani, G; Goginashvili, Z; Mosiava, T

2006-05-01

Reconstructive surgery of extremities is an object of a special attention of surgeons. Vessel and nerve damages, deficiency of soft tissue, bone, associated with infection results in a complete loss of extremity function, it also raises a question of amputation. The goal of the study was to improve the role of microsurgery in reconstructive surgery of limbs. We operated on 294 patients with various diseases and damages of extremities: pathology of nerves, vessels, tissue loss. An original method of treatment of large simultaneous functional defects of limbs has been used. Good functional and aesthetic results were obtained. Results of reconstructive operations on extremities might be improved by using of microsurgery methods. Microsurgery is deemed as a method of choice for extremities' reconstructive surgery as far as outcomes achieved through application of microsurgical technique significantly surpass the outcomes obtained through the use of routine surgical methods.

The development and validation of the AMPREDICT model for predicting mobility outcome after dysvascular lower extremity amputation.

PubMed

Czerniecki, Joseph M; Turner, Aaron P; Williams, Rhonda M; Thompson, Mary Lou; Landry, Greg; Hakimi, Kevin; Speckman, Rebecca; Norvell, Daniel C

2017-01-01

The objective of this study was the development of AMPREDICT-Mobility, a tool to predict the probability of independence in either basic or advanced (iBASIC or iADVANCED) mobility 1 year after dysvascular major lower extremity amputation. Two prospective cohort studies during consecutive 4-year periods (2005-2009 and 2010-2014) were conducted at seven medical centers. Multiple demographic and biopsychosocial predictors were collected in the periamputation period among individuals undergoing their first major amputation because of complications of peripheral arterial disease or diabetes. The primary outcomes were iBASIC and iADVANCED mobility, as measured by the Locomotor Capabilities Index. Combined data from both studies were used for model development and internal validation. Backwards stepwise logistic regression was used to develop the final prediction models. The discrimination and calibration of each model were assessed. Internal validity of each model was assessed with bootstrap sampling. Twelve-month follow-up was reached by 157 of 200 (79%) participants. Among these, 54 (34%) did not achieve iBASIC mobility, 103 (66%) achieved at least iBASIC mobility, and 51 (32%) also achieved iADVANCED mobility. Predictive factors associated with reduced odds of achieving iBASIC mobility were increasing age, chronic obstructive pulmonary disease, dialysis, diabetes, prior history of treatment for depression or anxiety, and very poor to fair self-rated health. Those who were white, were married, and had at least a high-school degree had a higher probability of achieving iBASIC mobility. The odds of achieving iBASIC mobility increased with increasing body mass index up to 30 kg/m 2 and decreased with increasing body mass index thereafter. The prediction model of iADVANCED mobility included the same predictors with the exception of diabetes, chronic obstructive pulmonary disease, and education level. Both models showed strong discrimination with C statistics of 0.85 and 0.82, respectively. The mean difference in predicted probabilities for those who did and did not achieve iBASIC and iADVANCED mobility was 33% and 29%, respectively. Tests for calibration and observed vs predicted plots suggested good fit for both models; however, the precision of the estimates of the predicted probabilities was modest. Internal validation through bootstrapping demonstrated some overoptimism of the original model development, with the optimism-adjusted C statistic for iBASIC and iADVANCED mobility being 0.74 and 0.71, respectively, and the discrimination slope 19% and 16%, respectively. AMPREDICT-Mobility is a user-friendly prediction tool that can inform the patient undergoing a dysvascular amputation and the patient's provider about the probability of independence in either basic or advanced mobility at each major lower extremity amputation level. Copyright © 2016 Society for Vascular Surgery. All rights reserved.

Estimation of in-situ bioremediation system cost using a hybrid Extreme Learning Machine (ELM)-particle swarm optimization approach

NASA Astrophysics Data System (ADS)

Yadav, Basant; Ch, Sudheer; Mathur, Shashi; Adamowski, Jan

2016-12-01

In-situ bioremediation is the most common groundwater remediation procedure used for treating organically contaminated sites. A simulation-optimization approach, which incorporates a simulation model for groundwaterflow and transport processes within an optimization program, could help engineers in designing a remediation system that best satisfies management objectives as well as regulatory constraints. In-situ bioremediation is a highly complex, non-linear process and the modelling of such a complex system requires significant computational exertion. Soft computing techniques have a flexible mathematical structure which can generalize complex nonlinear processes. In in-situ bioremediation management, a physically-based model is used for the simulation and the simulated data is utilized by the optimization model to optimize the remediation cost. The recalling of simulator to satisfy the constraints is an extremely tedious and time consuming process and thus there is need for a simulator which can reduce the computational burden. This study presents a simulation-optimization approach to achieve an accurate and cost effective in-situ bioremediation system design for groundwater contaminated with BTEX (Benzene, Toluene, Ethylbenzene, and Xylenes) compounds. In this study, the Extreme Learning Machine (ELM) is used as a proxy simulator to replace BIOPLUME III for the simulation. The selection of ELM is done by a comparative analysis with Artificial Neural Network (ANN) and Support Vector Machine (SVM) as they were successfully used in previous studies of in-situ bioremediation system design. Further, a single-objective optimization problem is solved by a coupled Extreme Learning Machine (ELM)-Particle Swarm Optimization (PSO) technique to achieve the minimum cost for the in-situ bioremediation system design. The results indicate that ELM is a faster and more accurate proxy simulator than ANN and SVM. The total cost obtained by the ELM-PSO approach is held to a minimum while successfully satisfying all the regulatory constraints of the contaminated site.

Superelastic Graphene Aerogel/Poly(3,4-Ethylenedioxythiophene)/MnO2 Composite as Compression-Tolerant Electrode for Electrochemical Capacitors

PubMed Central

Lv, Peng; Wang, Yaru; Ji, Chenglong; Yuan, Jiajiao

2017-01-01

Ultra-compressible electrodes with high electrochemical performance, reversible compressibility and extreme durability are in high demand in compression-tolerant energy storage devices. Herein, an ultra-compressible ternary composite was synthesized by successively electrodepositing poly(3,4-ethylenedioxythiophene) (PEDOT) and MnO2 into the superelastic graphene aerogel (SEGA). In SEGA/PEDOT/MnO2 ternary composite, SEGA provides the compressible backbone and conductive network; MnO2 is mainly responsible for pseudo reactions; the middle PEDOT not only reduces the interface resistance between MnO2 and graphene, but also further reinforces the strength of graphene cellar walls. The synergistic effect of the three components in the ternary composite electrode leads to high electrochemical performances and good compression-tolerant ability. The gravimetric capacitance of the compressible ternary composite electrodes reaches 343 F g−1 and can retain 97% even at 95% compressive strain. And a volumetric capacitance of 147.4 F cm−3 is achieved, which is much higher than that of other graphene-based compressible electrodes. This value of volumetric capacitance can be preserved by 80% after 3500 charge/discharge cycles under various compression strains, indicating an extreme durability.

Development trends in IR detector coolers

NASA Astrophysics Data System (ADS)

Mai, M.; Rühlich, I.; Wiedmann, Th.; Rosenhagen, C.

2009-05-01

For different IR application specific cooler requirements are needed to achieve best performance on system level. Handheld applications require coolers with highest efficiency and lowest weight. For application with continuous operation, i.e. border surveillance or homeland security, a very high MTTF is mandatory. Space applications additionally require extremely high reliability. In other application like fighter aircraft sufficient cooling capacity even at extreme high reject temperatures has to be provided. Meeting all this requirements within one cooler design is technically not feasible. Therefore, different coolers designs like integral rotary, split rotary or split linear are being employed. The use of flexure bearings supporting the driving mechanism has generated a new sub-group for the linear coolers; also, the coolers may either use a motor with moving magnet or with moving coil. AIM has mainly focussed on long life linear cooler technology and therefore developed a series of moving magnet flexure bearing compressors which meets MTTF's exceeding 20,000h (up to 50,000h with a Pulse-Tube coldfinger). These compressors have a full flexure bearing support on both sides of the driving mechanism. Cooler designs are being compared in regard to characteristic figures as described above.

Characterization of extreme ultraviolet laser ablation mass spectrometry for actinide trace analysis and nanoscale isotopic imaging

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

Green, Tyler; Kuznetsov, Ilya; Willingham, David

The purpose of this research was to characterize Extreme Ultraviolet Time-of-Flight (EUV TOF) Laser Ablation Mass Spectrometry for high spatial resolution elemental and isotopic analysis. We compare EUV TOF results with Secondary Ionization Mass Spectrometry (SIMS) to orient the EUV TOF method within the overall field of analytical mass spectrometry. Using the well-characterized NIST 61x glasses, we show that the EUV ionization approach produces relatively few molecular ion interferences in comparison to TOF SIMS. We demonstrate that the ratio of element ion to element oxide ion is adjustable with EUV laser pulse energy and that the EUV TOF instrument hasmore » a sample utilization efficiency of 0.014%. The EUV TOF system also achieves a lateral resolution of 80 nm and we demonstrate this lateral resolution with isotopic imaging of closely spaced particles or uranium isotopic standard materials.« less

Management of Lower Extremity Long-bone Fractures in Spinal Cord Injury Patients.

PubMed

Schulte, Leah M; Scully, Ryan D; Kappa, Jason E

2017-09-01

The AO classification system, used as a guide for modern fracture care and fixation, follows a basic philosophy of care that emphasizes early mobility and return to function. Lower extremity long-bone fractures in patients with spinal cord injury often are pathologic injuries that present unique challenges, to which the AO principles may not be entirely applicable. Optimal treatment achieves healing without affecting the functional level of the patient. These injuries often result from low-energy mechanisms in nonambulatory patients with osteopenic bone and a thin, insensate soft-tissue envelope. The complication rate can be high, and the outcomes can be catastrophic without proper care. Satisfactory results can be obtained through various methods of immobilization. Less frequently, internal fixation is applied. In certain cases, after discussion with the patient, amputation may be suitable. Prevention strategies aim to minimize bone loss and muscle atrophy.

Extremely Stable Polypyrrole Achieved via Molecular Ordering for Highly Flexible Supercapacitors.

PubMed

Huang, Yan; Zhu, Minshen; Pei, Zengxia; Huang, Yang; Geng, Huiyuan; Zhi, Chunyi

2016-01-27

The cycling stability of flexible supercapacitors with conducting polymers as electrodes is limited by the structural breakdown arising from repetitive counterion flow during charging/discharging. Supercapacitors made of facilely electropolymerized polypyrrole (e-PPy) have ultrahigh capacitance retentions of more than 97, 91, and 86% after 15000, 50000, and 100000 charging/discharging cycles, respectively, and can sustain more than 230000 charging/discharging cycles with still approximately half of the initial capacitance retained. To the best of our knowledge, such excellent long-term cycling stability was never reported. The fully controllable electropolymerization shows superiority in molecular ordering, favoring uniform stress distribution and charge transfer. Being left at ambient conditions for even 8 months, e-PPy supercapacitors completely retain the good electrochemical performance. The extremely stable supercapacitors with excellent flexibility and scalability hold considerable promise for the commerical application of flexible and wearable electronics.

System characterization of RiceWrist-S: a forearm-wrist exoskeleton for upper extremity rehabilitation.

PubMed

Pehlivan, Ali Utku; Rose, Chad; O'Malley, Marcia K

2013-06-01

Rehabilitation of the distal joints of the upper extremities is crucial to restore the ability to perform activities of daily living to patients with neurological lesions resulting from stroke or spinal cord injury. Robotic rehabilitation has been identified as a promising new solution, however, much of the existing technology in this field is focused on the more proximal joints of the upper arm. A recently presented device, the RiceWrist-S, focuses on the rehabilitation of the forearm and wrist, and has undergone a few important design changes. This paper first addresses the design improvements achieved in the recent design iteration, and then presents the system characterization of the new device. We show that the RiceWrist-S has capabilities beyond other existing devices, and exhibits favorable system characteristics as a rehabilitation device, in particular torque output, range of motion, closed loop position performance, and high spatial resolution.

Extremely efficient crystallization of HKUST-1 and Keggin-loaded related phases through the epoxide route.

PubMed

Oestreicher, Víctor; Jobbágy, Matías

2017-03-25

Highly crystalline HKUST-1 and COK-16-like phases were obtained based on a mild in situ alkalinization one-pot epoxide driven method. A slurry composed of finely ground trimesic acid, H 3 BTC, dispersed in a CuCl 2 aqueous solution quantitatively developed well crystallized HKUST-1 after the addition of propylene oxide. The use of solid H 3 BTC ensures a low concentration of free linker, favoring crystalline growth over the precipitation of amorphous or metastable impurities. An extreme space-time yield of 2.1 × 10 5 kg m -3 day -1 was reached, with no linker excess and minimum use of solvent. The method was equally efficient in the achievement of pure NENU/COK-16 phases, containing [PW 12 O 40 ] 3- , [PMo 12 O 40 ] 3- and [SiMo 12 O 40 ] 4- polyoxometalates.

High temperature sensing using higher-order-mode rejected sapphire-crystal fiber gratings

NASA Astrophysics Data System (ADS)

Zhan, Chun; Kim, Jae Hun; Lee, Jon; Yin, Stuart; Ruffin, Paul; Luo, Claire

2007-09-01

In this paper, we report the fabrication of higher-order-mode rejected fiber Bragg gratings (FBGs) in sapphire crystal fiber using infrared (IR) femtosecond laser illumination. The grating is tested in high temperature furnace up to 1600 degree Celsius. As sapphire fiber is only available as highly multimode fiber, a scheme to filter out higher order modes in favor for the fundamental mode is theoretically evaluated and experimentally demonstrated. The approach is to use an ultra thin sapphire crystal fiber (60 micron in diameter) to decrease the number of modes. The small diameter fiber also enables bending the fiber to certain radius which is carefully chosen to provide low loss for the fundamental mode LP01 and high loss for the other high-order modes. After bending, less-than-2-nm resonant peak bandwidth is achieved. The grating spectrum is improved, and higher resolution sensing measurement can be achieved. This mode filtering method is very easy to implement. Furthermore, the sapphire fiber is sealed with hi-purity alumina ceramic cement inside a flexible high temperature titanium tube, and the highly flexible titanium tube offers a robust packaging to sapphire fiber. Our high temperature sapphire grating sensor is very promising in extremely high temperature sensing application.

Graphene-Reinforced Aluminum Matrix Composites: A Review of Synthesis Methods and Properties

NASA Astrophysics Data System (ADS)

Chen, Fei; Gupta, Nikhil; Behera, Rakesh K.; Rohatgi, Pradeep K.

2018-06-01

Graphene-reinforced aluminum (Gr-Al) matrix nanocomposites (NCs) have attracted strong interest from both research and industry in high-performance weight-sensitive applications. Due to the vastly different bonding characteristics of the Al matrix (metallic) and graphene (in-plane covalent + inter-plane van der Waals), the graphene phase has a general tendency to agglomerate and phase separate in the metal matrix, which is detrimental for the mechanical and chemical properties of the composite. Thus, synthesis of Gr-Al NCs is extremely challenging. This review summarizes the different methods available to synthesize Gr-Al NCs and the resulting properties achieved in these NCs. Understanding the effect of processing parameters on the realized properties opens up the possibility of tailoring the synthesis methods to achieve the desired properties for a given application.

Pregestational diabetes with extreme insulin resistance: use of U-500 insulin in pregnancy.

PubMed

Zuckerwise, Lisa C; Werner, Erika F; Pettker, Christian M; McMahon-Brown, Erin K; Thung, Stephen F; Han, Christina S

2012-08-01

Increased insulin requirements in pregnancy can hinder attainment of glycemic control in diabetic patients. U-500 insulin is a concentrated form of regular insulin that can be a valuable tool in the treatment of patients with severe insulin resistance. A 24-year-old woman with pregestational diabetes mellitus experienced increasing insulin requirements during pregnancy, peaking at 650 units daily. The frequent, large-volume injections of standard-concentration insulin were poorly tolerated by the patient and resulted in nonadherence. She subsequently achieved glycemic control on thrice-daily U-500 insulin. Pregnancy exacerbates insulin resistance in diabetic patients, and these patients may require high doses of insulin. U-500 insulin is an effective alternative for patients with severe insulin resistance and should be considered for pregnant women with difficulty achieving glycemic control.

LSA silicon material task closed-cycle process development

NASA Technical Reports Server (NTRS)

Roques, R. A.; Wakefield, G. F.; Blocher, J. M., Jr.; Browning, M. F.; Wilson, W.

1979-01-01

The initial effort on feasibility of the closed cycle process was begun with the design of the two major items of untested equipment, the silicon tetrachloride by product converter and the rotary drum reactor for deposition of silicon from trichlorosilane. The design criteria of the initial laboratory equipment included consideration of the reaction chemistry, thermodynamics, and other technical factors. Design and construction of the laboratory equipment was completed. Preliminary silicon tetrachloride conversion experiments confirmed the expected high yield of trichlorosilane, up to 98 percent of theoretical conversion. A preliminary solar-grade polysilicon cost estimate, including capital costs considered extremely conservative, of $6.91/kg supports the potential of this approach to achieve the cost goal. The closed cycle process appears to have a very likely potential to achieve LSA goals.

Implicit Block ACK Scheme for IEEE 802.11 WLANs

PubMed Central

Sthapit, Pranesh; Pyun, Jae-Young

2016-01-01

The throughput of IEEE 802.11 standard is significantly bounded by the associated Medium Access Control (MAC) overhead. Because of the overhead, an upper limit exists for throughput, which is bounded, including situations where data rates are extremely high. Therefore, an overhead reduction is necessary to achieve higher throughput. The IEEE 802.11e amendment introduced the block ACK mechanism, to reduce the number of control messages in MAC. Although the block ACK scheme greatly reduces overhead, further improvements are possible. In this letter, we propose an implicit block ACK method that further reduces the overhead associated with IEEE 802.11e’s block ACK scheme. The mathematical analysis results are presented for both the original protocol and the proposed scheme. A performance improvement of greater than 10% was achieved with the proposed implementation.

Graphene-Reinforced Aluminum Matrix Composites: A Review of Synthesis Methods and Properties

NASA Astrophysics Data System (ADS)

Chen, Fei; Gupta, Nikhil; Behera, Rakesh K.; Rohatgi, Pradeep K.

2018-03-01

Graphene-reinforced aluminum (Gr-Al) matrix nanocomposites (NCs) have attracted strong interest from both research and industry in high-performance weight-sensitive applications. Due to the vastly different bonding characteristics of the Al matrix (metallic) and graphene (in-plane covalent + inter-plane van der Waals), the graphene phase has a general tendency to agglomerate and phase separate in the metal matrix, which is detrimental for the mechanical and chemical properties of the composite. Thus, synthesis of Gr-Al NCs is extremely challenging. This review summarizes the different methods available to synthesize Gr-Al NCs and the resulting properties achieved in these NCs. Understanding the effect of processing parameters on the realized properties opens up the possibility of tailoring the synthesis methods to achieve the desired properties for a given application.

Photonic-Assisted mm-Wave and THz Wireless Transmission towards 100 Gbit/s Data Rate

NASA Astrophysics Data System (ADS)

Freire Hermelo, Maria; Chuenchom, Rattana; Rymanov, Vitaly; Kaiser, Thomas; Sheikh, Fawad; Czylwik, Andreas; Stöhr, Andreas

2017-09-01

This paper presents photonic-assisted 60 GHz mm-wave and 325 GHz system approaches that enable the transmission of spectral-efficient and high data rate signals over fiber and over air. First, we focus on generic channel characteristics within the mm-wave 60 GHz band and at the terahertz (THz) band around 325 GHz. Next, for generating the high data rate baseband signals, we present a technical solution for constructing an extreme bandwidth arbitrary waveform generator (AWG). We then report the development of a novel coherent photonic mixer (CPX) module for direct optic-to-RF conversion of extreme wideband optical signals, with a>5 dB higher conversion gain compared to conventional photodiodes. Finally, we experimentally demonstrate record spectral efficient wireless transmission for both bands. The achieved spectral efficiencies reach 10 bit/s/Hz for the 60 GHz band and 6 bit/s/Hz for the 325 GHz band. The maximum data rate transmitted at THz frequencies in the 325 GHz band is 59 Gbit/s using a 64-QAM-OFDM modulation format and a 10 GHz wide data signal.

Shot-noise-limited optical Faraday polarimetry with enhanced laser noise cancelling

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

Li, Jiaming; Department of Physics, Indiana University Purdue University Indianapolis, Indianapolis, Indiana 46202; Luo, Le, E-mail: leluo@iupui.edu

2014-03-14

We present a shot-noise-limited measurement of optical Faraday rotations with sub-ten-nanoradian angular sensitivity. This extremely high sensitivity is achieved by using electronic laser noise cancelling and phase sensitive detection. Specially, an electronic laser noise canceller with a common mode rejection ratio of over 100 dB was designed and built for enhanced laser noise cancelling. By measuring the Faraday rotation of ambient air, we demonstrate an angular sensitivity of up to 9.0×10{sup −9} rad/√(Hz), which is limited only by the shot-noise of the photocurrent of the detector. To date, this is the highest angular sensitivity ever reported for Faraday polarimeters in the absencemore » of cavity enhancement. The measured Verdet constant of ambient air, 1.93(3)×10{sup −9}rad/(G cm) at 633 nm wavelength, agrees extremely well with the earlier experiments using high finesse optical cavities. Further, we demonstrate the applications of this sensitive technique in materials science by measuring the Faraday effect of an ultrathin iron film.« less

Polarization-selective optical resonance with extremely narrow linewidth in Si dimers array for application in ultra-sensitive refractive sensing

NASA Astrophysics Data System (ADS)

Fu, Dong; Zhang, Zuyin; Li, Jian; Wu, Haoyue; Wang, Wenbo; Wei, Xin

2017-05-01

By exploiting the radiative coupling between the electromagnetic field scattered by individual Si dimer and the collective wave diffracted (Rayleigh Anomalies) in the plane of Si dimers array, optical resonance with extremely narrow linewidth is achieved, accompanied with dramatic enhancement of electric field in the gap of the dimer. We analyze the optical properties of Si dimers array by decomposing it into three fundamental sub-systems. Theoretical investigation employing the coupled dipole approximation is complemented with numerical simulations. The result shows that polarization angle has significant influence on the orientation of the field scattered by individual Si dimer, which determines the efficiency of radiative coupling and further impacts on the electric field enhancement. Moreover, we explore the feasibility of application in refractive sensing. It is shown that the figure of merit value for the proposed system of Si dimers array is as high as 306. The Si dimers array that takes advantage of multiple coupling creates new possibility to implement field-enhanced spectroscopy and refractive sensing with ultra-high sensitivity.

Method for high-precision multi-layered thin film deposition for deep and extreme ultraviolet mirrors

DOEpatents

Ruffner, J.A.

1999-06-15

A method for coating (flat or non-flat) optical substrates with high-reflectivity multi-layer coatings for use at Deep Ultra-Violet (DUV) and Extreme Ultra-Violet (EUV) wavelengths. The method results in a product with minimum feature sizes of less than 0.10 [micro]m for the shortest wavelength (13.4 nm). The present invention employs a computer-based modeling and deposition method to enable lateral and vertical thickness control by scanning the position of the substrate with respect to the sputter target during deposition. The thickness profile of the sputter targets is modeled before deposition and then an appropriate scanning algorithm is implemented to produce any desired, radially-symmetric thickness profile. The present invention offers the ability to predict and achieve a wide range of thickness profiles on flat or figured substrates, i.e., account for 1/R[sup 2] factor in a model, and the ability to predict and accommodate changes in deposition rate as a result of plasma geometry, i.e., over figured substrates. 15 figs.

Cyanobacteria and microalgae: a renewable source of bioactive compounds and other chemicals.

PubMed

Encarnação, Telma; Pais, Alberto A C C; Campos, Maria G; Burrows, Hugh D

2015-01-01

Microalgae and cyanobacteria are rich sources of many valuable compounds, including important bioactive and biotechnologically relevant chemicals. Their enormous biodiversity, and the consequent variability in the respective biochemical composition, make microalgae cultivations a promising resource for many novel chemically and biologically active molecules and compounds of high commercial value such as lipids and dyes. The nature of the chemicals produced can be manipulated by changing the cultivation media and conditions. Algae are extremely versatile because they can be adapted to a variety of cell culture conditions. They do not require arable land, can be cultivated on saline water and wastewaters, and require much less water than plants. They possess an extremely high growth rate making these microorganisms very attractive for use in biofuel production--some species of algae can achieve around 100 times more oil than oil seeds. In addition, microalgae and cyanobacteria can accumulate various biotoxins and can contribute to mitigate greenhouse gases since they produce biomass through carbon dioxide fixation. In this review, we provide an overview of the application of microalgae in the production of bioactive and other chemicals.

Not an Oxymoron: Some X-ray Binary Pulsars with Enormous Spinup Rates Reveal Weak Magnetic Fields

NASA Astrophysics Data System (ADS)

Christodoulou, D. M.; Laycock, S. G. T.; Kazanas, D.

2018-05-01

Three high-mass X-ray binaries have been discovered recently exhibiting enormous spinup rates. Conventional accretion theory predicts extremely high surface dipolar magnetic fields that we believe are unphysical. Instead, we propose quite the opposite scenario: some of these pulsars exhibit weak magnetic fields, so much so that their magnetospheres are crushed by the weight of inflowing matter. The enormous spinup rate is achieved before inflowing matter reaches the pulsar's surface as the penetrating inner disk transfers its excess angular momentum to the receding magnetosphere which, in turn, applies a powerful spinup torque to the pulsar. This mechanism also works in reverse: it spins a pulsar down when the magnetosphere expands beyond corotation and finds itself rotating faster than the accretion disk which then exerts a powerful retarding torque to the magnetic field and to the pulsar itself. The above scenaria cannot be accommodated within the context of neutron-star accretion processes occurring near spin equilibrium, thus they constitute a step toward a new theory of extreme (far from equilibrium) accretion phenomena.

Simultaneous excitation of extremely high-Q-factor trapped and octupolar modes in terahertz metamaterials.

PubMed

Yang, Shengyan; Tang, Chengchun; Liu, Zhe; Wang, Bo; Wang, Chun; Li, Junjie; Wang, Li; Gu, Changzhi

2017-07-10

Achieving high-Q-factor resonances allows dramatic enhancement of performance of many plasmonic devices. However, the excitation of high-Q-factor resonance, especially multiple high-Q-factor resonances, has been a big challenge in traditional metamaterials due to the ohmic and radiation losses. Here, we experimentally demonstrate simultaneous excitation of double extremely sharp resonances in a terahertz metamaterial composed of mirror-symmetric-broken double split ring resonators (MBDSRRs). In a regular mirror-arranged SRR array, only the low-Q-factor dipole resonance can be excited with the external electric field perpendicular to the SRR gap. Breaking the mirror-symmetry of the metamaterial leads to the occurrence of two distinct otherwise inaccessible ultrahigh-Q-factor modes, which consists of one trapped mode in addition to an octupolar mode. By tuning the asymmetry parameter, the Q factor of the trapped mode can be linearly modulated, while the Q factor of the octupolar mode can be tailored exponentially. For specific degree of asymmetry, our simulations revealed a significantly high Q factor (Q>100) for the octupolar mode, which is more than one order of magnitude larger than that of conventional metamaterials. The mirror-symmetry-broken metamaterial offers the advantage of enabling access to two distinct high-Q-factor resonances which could be exploited for ultrasensitive sensors, multiband filters, and slow light devices.

β-Cobalt sulfide nanoparticles decorated graphene composite electrodes for high capacity and power supercapacitors

NASA Astrophysics Data System (ADS)

Qu, Baihua; Chen, Yuejiao; Zhang, Ming; Hu, Lingling; Lei, Danni; Lu, Bingan; Li, Qiuhong; Wang, Yanguo; Chen, Libao; Wang, Taihong

2012-11-01

Electrochemical supercapacitors have drawn much attention because of their high power and reasonably high energy densities. However, their performances still do not reach the demand of energy storage. In this paper β-cobalt sulfide nanoparticles were homogeneously distributed on a highly conductive graphene (CS-G) nanocomposite, which was confirmed by transmission electron microscopy analysis, and exhibit excellent electrochemical performances including extremely high values of specific capacitance (~1535 F g-1) at a current density of 2 A g-1, high-power density (11.98 kW kg-1) at a discharge current density of 40 A g-1 and excellent cyclic stability. The excellent electrochemical performances could be attributed to the graphene nanosheets (GNSs) which could maintain the mechanical integrity. Also the CS-G nanocomposite electrodes have high electrical conductivity. These results indicate that high electronic conductivity of graphene nanocomposite materials is crucial to achieving high power and energy density for supercapacitors.

β-Cobalt sulfide nanoparticles decorated graphene composite electrodes for high capacity and power supercapacitors.

PubMed

Qu, Baihua; Chen, Yuejiao; Zhang, Ming; Hu, Lingling; Lei, Danni; Lu, Bingan; Li, Qiuhong; Wang, Yanguo; Chen, Libao; Wang, Taihong

2012-12-21

Electrochemical supercapacitors have drawn much attention because of their high power and reasonably high energy densities. However, their performances still do not reach the demand of energy storage. In this paper β-cobalt sulfide nanoparticles were homogeneously distributed on a highly conductive graphene (CS-G) nanocomposite, which was confirmed by transmission electron microscopy analysis, and exhibit excellent electrochemical performances including extremely high values of specific capacitance (~1535 F g(-1)) at a current density of 2 A g(-1), high-power density (11.98 kW kg(-1)) at a discharge current density of 40 A g(-1) and excellent cyclic stability. The excellent electrochemical performances could be attributed to the graphene nanosheets (GNSs) which could maintain the mechanical integrity. Also the CS-G nanocomposite electrodes have high electrical conductivity. These results indicate that high electronic conductivity of graphene nanocomposite materials is crucial to achieving high power and energy density for supercapacitors.

Suitability of holographic beam scanning in high resolution applications

NASA Astrophysics Data System (ADS)

Kalita, Ranjan; Goutam Buddha, S. S.; Boruah, Bosanta R.

2018-02-01

The high resolution applications of a laser scanning imaging system very much demand the accurate positioning of the illumination beam. The galvanometer scanner based beam scanning imaging systems, on the other hand, suffer from both short term and long term beam instability issues. Fortunately Computer generated holography based beam scanning offers extremely accurate beam steering, which can be very useful for imaging in high-resolution applications in confocal microscopy. The holographic beam scanning can be achieved by writing a sequence of holograms onto a spatial light modulator and utilizing one of the diffracted orders as the illumination beam. This paper highlights relative advantages of such a holographic beam scanning based confocal system and presents some of preliminary experimental results.

Laser absorption spectroscopy of oxygen confined in highly porous hollow sphere xerogel.

PubMed

Yang, Lin; Somesfalean, Gabriel; He, Sailing

2014-02-10

An Al2O3 xerogel with a distinctive microstructure is studied for the application of laser absorption spectroscopy of oxygen. The xerogel has an exceptionally high porosity (up to 88%) and a large pore size (up to 3.6 µm). Using the method of gas-in-scattering media absorption spectroscopy (GASMAS), a long optical path length (about 3.5m) and high enhancement factor (over 300 times) are achieved as the result of extremely strong multiple-scattering when the light is transmitted through the air-filled, hollow-sphere alumina xerogel. We investigate how the micro-physical feature influences the optical property. As part of the optical sensing system, the material's gas exchange dynamics are also experimentally studied.

A Partnership between English Language Learners and a Team of Rocket Scientists: EPO for the NASA SDO Extreme Ultraviolet Variability Experiment (EVE)

NASA Astrophysics Data System (ADS)

Buhr, S. M.; McCaffrey, M. S.; Eparvier, F.; Murillo, M.

2008-05-01

Recent immigrant high school students were successfully engaged in learning about Sun-Earth connections through a partnership with the NASA Solar Dynamics Observatory Extreme Ultraviolet Variability Experiment (EVE) project. The students were enrolled in a pilot course as part of the Math, Engineering and Science Achievement (MESA) program. The English Language Learner (ELL) students doubled their achievement on a pre- and post- assessment on the content of the course. Students learned scientific content and vocabulary in English with support in Spanish, attended field trips, hosted scientist speakers, built antenna and deployed space weather monitors as part of the Stanford SOLAR project, and gave final presentations in English, showcasing their new computer skills. Teachers who taught the students in other courses noted gains in the students' willingness to use English in class and noted gains in math skills. The course has been broken into modules for use in shorter after-school environments, or for use by EVE scientists who are outside of the Boulder area. Video footage of "The Making of a Satellite", and "All About EVE" is completed for use in the kits. Other EVE EPO includes upcoming professional development for teachers and content workshops for journalists.

Lightweight, compact, and high-performance 3T MR system for imaging the brain and extremities.

PubMed

Foo, Thomas K F; Laskaris, Evangelos; Vermilyea, Mark; Xu, Minfeng; Thompson, Paul; Conte, Gene; Van Epps, Christopher; Immer, Christopher; Lee, Seung-Kyun; Tan, Ek T; Graziani, Dominic; Mathieu, Jean-Baptise; Hardy, Christopher J; Schenck, John F; Fiveland, Eric; Stautner, Wolfgang; Ricci, Justin; Piel, Joseph; Park, Keith; Hua, Yihe; Bai, Ye; Kagan, Alex; Stanley, David; Weavers, Paul T; Gray, Erin; Shu, Yunhong; Frick, Matthew A; Campeau, Norbert G; Trzasko, Joshua; Huston, John; Bernstein, Matt A

2018-03-13

To build and evaluate a small-footprint, lightweight, high-performance 3T MRI scanner for advanced brain imaging with image quality that is equal to or better than conventional whole-body clinical 3T MRI scanners, while achieving substantial reductions in installation costs. A conduction-cooled magnet was developed that uses less than 12 liters of liquid helium in a gas-charged sealed system, and standard NbTi wire, and weighs approximately 2000 kg. A 42-cm inner-diameter gradient coil with asymmetric transverse axes was developed to provide patient access for head and extremity exams, while minimizing magnet-gradient interactions that adversely affect image quality. The gradient coil was designed to achieve simultaneous operation of 80-mT/m peak gradient amplitude at a slew rate of 700 T/m/s on each gradient axis using readily available 1-MVA gradient drivers. In a comparison of anatomical imaging in 16 patients using T 2 -weighted 3D fluid-attenuated inversion recovery (FLAIR) between the compact 3T and whole-body 3T, image quality was assessed as equivalent to or better across several metrics. The ability to fully use a high slew rate of 700 T/m/s simultaneously with 80-mT/m maximum gradient amplitude resulted in improvements in image quality across EPI, DWI, and anatomical imaging of the brain. The compact 3T MRI system has been in continuous operation at the Mayo Clinic since March 2016. To date, over 200 patient studies have been completed, including 96 comparison studies with a clinical 3T whole-body MRI. The increased gradient performance has reliably resulted in consistently improved image quality. © 2018 International Society for Magnetic Resonance in Medicine.

Simultaneous Delivery of Multiple Antibacterial Agents from Additively Manufactured Porous Biomaterials to Fully Eradicate Planktonic and Adherent Staphylococcus aureus.

PubMed

Bakhshandeh, S; Gorgin Karaji, Z; Lietaert, K; Fluit, A C; Boel, C H E; Vogely, H C; Vermonden, T; Hennink, W E; Weinans, H; Zadpoor, A A; Amin Yavari, S

2017-08-09

Implant-associated infections are notoriously difficult to treat and may even result in amputation and death. The first few days after surgery are the most critical time to prevent those infections, preferably through full eradication of the micro-organisms entering the body perioperatively. That is particularly important for patients with a compromised immune system such as orthopedic oncology patients, as they are at higher risk for infection and complications. Full eradication of bacteria is, especially in a biofilm, extremely challenging due to the toxicity barrier that prevents delivery of high doses of antibacterial agents. This study aimed to use the potential synergistic effects of multiple antibacterial agents to prevent the use of toxic levels of these agents and achieve full eradication of planktonic and adherent bacteria. Silver ions and vancomycin were therefore simultaneously delivered from additively manufactured highly porous titanium implants with an extremely high surface area incorporating a bactericidal coating made from chitosan and gelatin applied by electrophoretic deposition (EPD). The presence of the chitosan/gelatin (Ch+Gel) coating, Ag, and vancomycin (Vanco) was confirmed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The release of vancomycin and silver ions continued for at least 21 days as measured by inductively coupled plasma (ICP) and UV-spectroscopy. Antibacterial behavior against Staphylococcus aureus, both planktonic and in biofilm, was evaluated for up to 21 days. The Ch+Gel coating showed some bactericidal behavior on its own, while the loaded hydrogels (Ch+Gel+Ag and Ch+Gel+Vanco) achieved full eradication of both planktonic and adherent bacteria without causing significant levels of toxicity. Combining silver and vancomycin improved the release profiles of both agents and revealed a synergistic behavior that further increased the bactericidal effects.

Simultaneous Delivery of Multiple Antibacterial Agents from Additively Manufactured Porous Biomaterials to Fully Eradicate Planktonic and Adherent Staphylococcus aureus

PubMed Central

2017-01-01

Implant-associated infections are notoriously difficult to treat and may even result in amputation and death. The first few days after surgery are the most critical time to prevent those infections, preferably through full eradication of the micro-organisms entering the body perioperatively. That is particularly important for patients with a compromised immune system such as orthopedic oncology patients, as they are at higher risk for infection and complications. Full eradication of bacteria is, especially in a biofilm, extremely challenging due to the toxicity barrier that prevents delivery of high doses of antibacterial agents. This study aimed to use the potential synergistic effects of multiple antibacterial agents to prevent the use of toxic levels of these agents and achieve full eradication of planktonic and adherent bacteria. Silver ions and vancomycin were therefore simultaneously delivered from additively manufactured highly porous titanium implants with an extremely high surface area incorporating a bactericidal coating made from chitosan and gelatin applied by electrophoretic deposition (EPD). The presence of the chitosan/gelatin (Ch+Gel) coating, Ag, and vancomycin (Vanco) was confirmed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The release of vancomycin and silver ions continued for at least 21 days as measured by inductively coupled plasma (ICP) and UV-spectroscopy. Antibacterial behavior against Staphylococcus aureus, both planktonic and in biofilm, was evaluated for up to 21 days. The Ch+Gel coating showed some bactericidal behavior on its own, while the loaded hydrogels (Ch+Gel+Ag and Ch+Gel+Vanco) achieved full eradication of both planktonic and adherent bacteria without causing significant levels of toxicity. Combining silver and vancomycin improved the release profiles of both agents and revealed a synergistic behavior that further increased the bactericidal effects. PMID:28696671

Technology update: Tethered aerostat structural design and material developments

NASA Technical Reports Server (NTRS)

Witherow, R. G.

1975-01-01

Requirements exist for an extremely stable, high performance, all-weather tethered aerostat system. This requirement has been satisfied by a 250,000 cubic foot captive buoyant vehicle as demonstrated by over a year of successful field operations. This achievement required significant advancements in several technology areas including composite materials design, aerostatics and aerodynamics, structural design, electro-mechanical design, vehicle fabrication and mooring operations. This paper specifically addresses the materials and structural design aspects of pressurized buoyant vehicles as related to the general class of Lighter Than Air vehicles.

Tunable Diode Laser Heterodyne Spectrophotometry of Ozone

NASA Technical Reports Server (NTRS)

Fogal, P. F.; McElroy, C. T.; Goldman, A.; Murcray, D. G.

1988-01-01

Tunable diode laser heterodyne spectrophotometry (TDLHS) has been used to make extremely high resolution (less than 0.0005/ cm) solar spectra in the 9.6 micron ozone band. Observations have shown that a signal-to-noise ratio of 95 : 1 (35% of theoretical) for an integration time of 1/8 second can be achieved at a resolution of 0.0005 wavenumbers. The spectral data have been inverted to yield a total column amount of ozone, in good agreement with that. measured at the nearby National Oceanographic and Atmospheric Administration (NOAA) ozone monitoring facility in Boulder, Colorado.

Erosion resistant nozzles for laser plasma extreme ultraviolet (EUV) sources

DOEpatents

Kubiak, Glenn D.; Bernardez, II, Luis J.

2000-01-04

A gas nozzle having an increased resistance to erosion from energetic plasma particles generated by laser plasma sources. By reducing the area of the plasma-facing portion of the nozzle below a critical dimension and fabricating the nozzle from a material that has a high EUV transmission as well as a low sputtering coefficient such as Be, C, or Si, it has been shown that a significant reduction in reflectance loss of nearby optical components can be achieved even after exposing the nozzle to at least 10.sup.7 Xe plasma pulses.

Management of Breast Sarcoma.

PubMed

Hsu, Cary; McCloskey, Susan A; Peddi, Parvin F

2016-10-01

Breast sarcomas are exceptionally rare mesenchymal neoplasms composed of many histologic subtypes. Therapy is guided by principles established in the management of extremity sarcomas. The anatomic site does influence treatment decisions, particularly the surgical management. Surgery should be undertaken with the aim of achieving a widely negative margin. Selected patients can be managed with breast-conserving surgery. Breast reconstruction is increasingly being undertaken for selected patients. Radiation therapy and chemotherapy are used selectively for large, high-grade sarcomas for which there is significant concern for local and distant recurrence. Copyright © 2016 Elsevier Inc. All rights reserved.

A Study to Assess the Achievement Motivation of Higher Secondary Students in Relation to Their Noise Sensitivity

ERIC Educational Resources Information Center

Latha, Prema

2014-01-01

Disturbing sounds are often referred to as noise, and if extreme enough in degree, intensity or frequency, it is referred to as noise pollution. Achievement refers to a change in study behavior in relation to their noise sensitivity and learning in the educational sense by achieving results in changed responses to certain types of stimuli like…

High power pulsed sources based on fiber amplifiers

NASA Astrophysics Data System (ADS)

Canat, Guillaume; Jaouën, Yves; Mollier, Jean-Claude; Bouzinac, Jean-Pierre; Cariou, Jean-Pierre

2017-11-01

Cladding-pumped rare-earth-doped fiber laser technologies are currently among the best sources for high power applications. Theses extremely compact and robust sources appoint them as good candidate for aeronautical and space applications. The double-clad (DC) fiber converts the poor beamquality of high-power large-area pump diodes from the 1st cladding to laser light at another wavelength guided in an active single-mode core. High-power coherent MOPA (Master Oscillator Power Amplifier) sources (several 10W CW or several 100W in pulsed regime) will soon be achieved. Unfortunately it also brings nonlinear effects which quickly impairs output signal distortions. Stimulated Brillouin scattering (SBS) and optical parametric amplification (OPA) have been shown to be strong limitations. Based on amplifier modeling and experiments we discuss the performances of these sources.

Generation of µW level plateau harmonics at high repetition rate.

PubMed

Hädrich, S; Krebs, M; Rothhardt, J; Carstens, H; Demmler, S; Limpert, J; Tünnermann, A

2011-09-26

The process of high harmonic generation allows for coherent transfer of infrared laser light to the extreme ultraviolet spectral range opening a variety of applications. The low conversion efficiency of this process calls for optimization or higher repetition rate intense ultrashort pulse lasers. Here we present state-of-the-art fiber laser systems for the generation of high harmonics up to 1 MHz repetition rate. We perform measurements of the average power with a calibrated spectrometer and achieved µW harmonics between 45 nm and 61 nm (H23-H17) at a repetition rate of 50 kHz. Additionally, we show the potential for few-cycle pulses at high average power and repetition rate that may enable water-window harmonics at unprecedented repetition rate. © 2011 Optical Society of America

Neonatal systemic inflammation and the risk of low scores on measures of reading and mathematics achievement at age 10 years among children born extremely preterm.

PubMed

Leviton, Alan; Dammann, Olaf; Allred, Elizabeth N; Joseph, Robert M; Fichorova, Raina N; O'Shea, T Michael; Kuban, Karl C K

2018-05-01

Difficulties with reading and math occur more commonly among children born extremely preterm than among children born at term. Reasons for this are unclear. We measured the concentrations of 27 inflammatory-related and neurotrophic/angiogenic proteins (angio-neurotrophic proteins) in multiple blood specimens collected a week apart during the first postnatal month from 660 children born before the 28th week of gestation who at age 10 years had an IQ ≥ 70 and a Wechsler Individual Achievement Test 3rd edition (WIAT-III) assessment. We identified four groups of children, those who had a Z-score ≤ -1 on the Word Reading assessment only, on the Numerical Operations assessment only, on both of these assessments, and on neither, which served as the referent group. We then modeled the risk of each learning limitation associated with a top quartile concentration of each protein, and with high and lower concentrations of multiple proteins. The protein profile of low reading scores was confined to the third and fourth postnatal weeks when increased risks were associated with high concentrations of IL-8 and ICAM-1 in the presence of low concentrations of angio-neurotrophic proteins. The profile of low math scores was very similar, except it did not include ICAM-1. In contrast, the profile of low scores on both assessments was present in each of the first four postnatal weeks. The increased risks associated with high concentrations of TNF-α in the first two weeks and of IL-8 and ICAM-1 in the next two weeks were modulated down by high concentrations of angio-neurotrophic proteins. High concentrations of angio-neurotrophic proteins appear to reduce/moderate the risk of each learning limitation associated with systemic inflammation. The three categories of limitations have protein profiles with some similarities, and yet some differences, too. Copyright © 2018 ISDN. Published by Elsevier Ltd. All rights reserved.

Towards a real-time wide area motion imagery system

NASA Astrophysics Data System (ADS)

Young, R. I.; Foulkes, S. B.

2015-10-01

It is becoming increasingly important in both the defence and security domains to conduct persistent wide area surveillance (PWAS) of large populations of targets. Wide Area Motion Imagery (WAMI) is a key technique for achieving this wide area surveillance. The recent development of multi-million pixel sensors has provided sensors with wide field of view replete with sufficient resolution for detection and tracking of objects of interest to be achieved across these extended areas of interest. WAMI sensors simultaneously provide high spatial and temporal resolutions, giving extreme pixel counts over large geographical areas. The high temporal resolution is required to enable effective tracking of targets. The provision of wide area coverage with high frame rates generates data deluge issues; these are especially profound if the sensor is mounted on an airborne platform, with finite data-link bandwidth and processing power that is constrained by size, weight and power (SWAP) limitations. These issues manifest themselves either as bottlenecks in the transmission of the imagery off-board or as latency in the time taken to analyse the data due to limited computational processing power.

Achievement of normally-off AlGaN/GaN high-electron mobility transistor with p-NiOx capping layer by sputtering and post-annealing

NASA Astrophysics Data System (ADS)

Huang, Shyh-Jer; Chou, Cheng-Wei; Su, Yan-Kuin; Lin, Jyun-Hao; Yu, Hsin-Chieh; Chen, De-Long; Ruan, Jian-Long

2017-04-01

In this paper, we present a technique to fabricate normally off GaN-based high-electron mobility transistor (HEMT) by sputtering and post-annealing p-NiOx capping layer. The p-NiOx layer is produced by sputtering at room temperature and post-annealing at 500 °C for 30 min in pure O2 environment to achieve high hole concentration. The Vth shifts from -3 V in the conventional transistor to 0.33 V, and on/off current ratio became 107. The forward and reverse gate breakdown increase from 3.5 V and -78 V to 10 V and -198 V, respectively. The reverse gate leakage current is 10-9 A/mm, and the off-state drain-leakage current is 10-8 A/mm. The Vth hysteresis is extremely small at about 33 mV. We also investigate the mechanism that increases hole concentration of p-NiOx after annealing in oxygen environment resulted from the change of Ni2+ to Ni3+ and the surge of (111)-orientation.

Detection of IL-6 by magnetic nanoparticles grown with the assistance of mid-infrared lighting.

PubMed

Jiang, Xiufeng; Zhang, Ye; Miao, Xiaofei; Li, Zenghui; Bao, Zengtao; Wang, Tong

2013-01-01

Nanomedical systems have attracted considerable attention primarily due to suitability in applications for specific cell selection through biomolecular targeting and rare cell detection enhancement in a diverse, multicellular population. In the present study, magnetic nanoparticles were prepared for use in high accuracy cell sensing. Magnetic nanoparticle growth was assisted by mid-infrared lighting. By this mechanism, a narrow window, estimated to be 2%, was achieved for the dimension distribution of grown nanoparticles. Combined with silicon nanowire (SiNW) transistors, a sensor with ultra high sensitivity for the detection of specific potential low abundance biomarkers has been achieved, which has been specifically used to detect interleukin-6 (IL-6) at extremely low concentrations. A novel biosensor with high sensitivity has been fabricated and utilized in the detection of IL-6 at 75 fM to 50 pM. The system consists of an SiNW transistor and magnetic nanoparticles with even dimension distribution. The novel sensor system is suitable for quantifying IL-6 at low concentrations in protein samples.

Infrared nano-sensor based on doubly splited optomechanical cavity

NASA Astrophysics Data System (ADS)

Zhang, Yeping; Ai, Jie; Xiang, Yanjun; Ma, Liehua; Li, Tao; Ma, Jingfang

2017-10-01

Optomechanical crystal (OMC) cavities are simultaneous have photonic and phononic bandgaps. The strong interaction between high co-localized optical mode and mechanical mode are excellent candidates for precision measurements due to their simplicity, sensitivity and all optical operation. Here, we investigate OMC nanobeam cavities in silicon operating at the near-infrared wavelengths to achieve high optomechanical coupling rate and ultra-small motion mass. Numerical simulation results show that the optical Q-factor reached to 1.2×105 , which possesses an optical mode resonating at the wavelength of 1181 nm and the extremely localized mechanical mode vibrating at 9.2GHz. Moreover, a novel type of doubly splited nanocavity tailored to sensitively measure torques and mass. In the nanomechanical resonator central hollow area suspended low-mass elements (<100fg) are sensitive to environmental stimulate. By changing the split width, an ultra-small effective motion mass of only 4fg with a mechanical frequency as high as 11.9GHz can be achieved, while the coupling rate up to 1.58MHz. Potential applications on these devices include sensing mass, acceleration, displacement, and magnetic probing the quantum properties of nanoscale systems.

Experiments on 1,000 km/s flyer acceleration and collisions

NASA Astrophysics Data System (ADS)

Karasik, Max; Weaver, J. L.; Aglitskiy, Y.; Kehne, D. M.; Zalesak, S. T.; Velikovich, A. L.; Oh, J.; Serlin, V.; Obenschain, S. P.

2012-10-01

We will present results from follow-on experiments to the record-high velocities achieved using the ultra-uniform deep-uv drive of the Nike KrF laser [Karasik et al, Phys. Plasmas 17, 056317 (2010)], in which highly accelerated planar foils of deuterated polystyrene were made to collide with a witness foil to produce ˜1 Gbar shock pressures and result in heating of matter to thermonuclear temperatures. Such velocities may indicate a path to lower minimum energy required for central ignition. Still higher velocities and higher target densities are required for impact fast ignition. New results give velocity of >1,100 km/s achieved through improvements in pulseshaping. Variation of second foil parameters results in significant change in fusion neutron production on impact. In-flight target density is inferred from target heating upon collision via DD neutron time-of-flight ion temperature measurement. Availability of pressures generated by collisions of such highly accelerated flyers may provide an experimental platform for study of matter at extreme conditions. Work is supported by US DOE (NNSA).

Scalable Parallel Density-based Clustering and Applications

NASA Astrophysics Data System (ADS)

Patwary, Mostofa Ali

2014-04-01

Recently, density-based clustering algorithms (DBSCAN and OPTICS) have gotten significant attention of the scientific community due to their unique capability of discovering arbitrary shaped clusters and eliminating noise data. These algorithms have several applications, which require high performance computing, including finding halos and subhalos (clusters) from massive cosmology data in astrophysics, analyzing satellite images, X-ray crystallography, and anomaly detection. However, parallelization of these algorithms are extremely challenging as they exhibit inherent sequential data access order, unbalanced workload resulting in low parallel efficiency. To break the data access sequentiality and to achieve high parallelism, we develop new parallel algorithms, both for DBSCAN and OPTICS, designed using graph algorithmic techniques. For example, our parallel DBSCAN algorithm exploits the similarities between DBSCAN and computing connected components. Using datasets containing up to a billion floating point numbers, we show that our parallel density-based clustering algorithms significantly outperform the existing algorithms, achieving speedups up to 27.5 on 40 cores on shared memory architecture and speedups up to 5,765 using 8,192 cores on distributed memory architecture. In our experiments, we found that while achieving the scalability, our algorithms produce clustering results with comparable quality to the classical algorithms.

Optimisation and validation of a rapid and efficient microemulsion liquid chromatographic (MELC) method for the determination of paracetamol (acetaminophen) content in a suppository formulation.

PubMed

McEvoy, Eamon; Donegan, Sheila; Power, Joe; Altria, Kevin

2007-05-09

A rapid and efficient oil-in-water microemulsion liquid chromatographic method has been optimised and validated for the analysis of paracetamol in a suppository formulation. Excellent linearity, accuracy, precision and assay results were obtained. Lengthy sample pre-treatment/extraction procedures were eliminated due to the solubilising power of the microemulsion and rapid analysis times were achieved. The method was optimised to achieve rapid analysis time and relatively high peak efficiencies. A standard microemulsion composition of 33 g SDS, 66 g butan-1-ol, 8 g n-octane in 1l of 0.05% TFA modified with acetonitrile has been shown to be suitable for the rapid analysis of paracetamol in highly hydrophobic preparations under isocratic conditions. Validated assay results and overall analysis time of the optimised method was compared to British Pharmacopoeia reference methods. Sample preparation and analysis times for the MELC analysis of paracetamol in a suppository were extremely rapid compared to the reference method and similar assay results were achieved. A gradient MELC method using the same microemulsion has been optimised for the resolution of paracetamol and five of its related substances in approximately 7 min.

Anterolateral thigh flap harvested from paralytic lower extremity in a patient with late polio sequel.

PubMed

Valentini, Valentino; Terenzi, Valentina; Cassoni, Andrea; Battisti, Andrea; Della Monaca, Marco; Malavasi, Roberto

2012-01-01

Free flap reconstruction is the treatment of choice after extensive head and neck tumour resection. When treating a patient with a previous disability, such as lower extremity paralysis secondary to poliomyelitis, it is important to offer the best reconstruction whilst preserving healthy extremities. We report the case of a 51-year-old man with a squamous cell carcinoma (SCC) of the right tongue and a left lower extremity paralysis secondary to an acute poliomyelitis during childhood in which reconstruction was successfully achieved with a left anterolateral thigh (ALT) free flap. Copyright © 2011 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Electric-field-induced extremely large change in resistance in graphene ferromagnets

NASA Astrophysics Data System (ADS)

Song, Yu

2018-01-01

A colossal magnetoresistance (˜100×10^3% ) and an extremely large magnetoresistance (˜1×10^6% ) have been previously explored in manganite perovskites and Dirac materials, respectively. However, the requirement of an extremely strong magnetic field (and an extremely low temperature) makes them not applicable for realistic devices. In this work, we propose a device that can generate even larger changes in resistance in a zero-magnetic field and at a high temperature. The device is composed of graphene under two strips of yttrium iron garnet (YIG), where two gate voltages are applied to cancel the heavy charge doping in the YIG-induced half-metallic ferromagnets. By calculations using the Landauer-Büttiker formalism, we demonstrate that, when a proper gate voltage is applied on the free ferromagnet, changes in resistance up to 305×10^6% (16×10^3% ) can be achieved at the liquid helium (nitrogen) temperature and in a zero magnetic field. We attribute such a remarkable effect to a gate-induced full-polarization reversal in the free ferromagnet, which results in a metal-state to insulator-state transition in the device. We also find that the proposed effect can be realized in devices using other magnetic insulators, such as EuO and EuS. Our work should be helpful for developing a realistic switching device that is energy saving and CMOS-technology compatible.

Bioinspired Mechano‐Sensitive Macroporous Ceramic Sponge for Logical Drug and Cell Delivery

PubMed Central

Xu, Changlu; Wei, Zhihao; Gao, Huajian; Bai, Yanjie; Liu, Huiling; Yang, Huilin

2017-01-01

On‐demand, ultrahigh precision delivery of molecules and cells assisted by scaffold is a pivotal theme in the field of controlled release, but it remains extremely challenging for ceramic‐based macroporous scaffolds that are prevalently used in regenerative medicine. Sea sponges (Phylum Porifera), whose bodies possess hierarchical pores or channels and organic/inorganic composite structures, can delicately control water intake/circulation and therefore achieve high precision mass transportation of food, oxygen, and wastes. Inspired by leuconoid sponge, in this study, the authors design and fabricate a biomimetic macroporous ceramic composite sponge (CCS) for high precision logic delivery of molecules and cells regulated by mechanical stimulus. The CCS reveals unique on‐demand AND logic release behaviors in response to dual‐gates of moisture and pressure (or strain) and, more importantly, 1 cm3 volume of CCS achieves unprecedentedly delivery precision of ≈100 ng per cycle for hydrophobic or hydrophilic molecules and ≈1400 cells per cycle for fibroblasts, respectively. PMID:28638781

Proximity Link Design and Performance Options for a Mars Areostationary Relay Satellite

NASA Technical Reports Server (NTRS)

Edwards, Charles D.; Bell, David J.; Biswas, Abhijit; Cheung, Kar-Ming; Lock, Robert E.

2016-01-01

Current and near-term Mars relay telecommunications services are provided by a set of NASA and ESA Mars science orbiters equipped with UHF relay communication payloads employing operationally simple low-gain antennas. These have been extremely successful in supporting a series of landed Mars mission, greatly increasing data return relative to direct-to-Earth lander links. Yet their relay services are fundamentally constrained by the short contact times available from the selected science orbits. Future Mars areostationary orbiters, flying in circular, equatorial, 1- sol orbits, offer the potential for continuous coverage of Mars landers and rovers, radically changing the relay support paradigm. Achieving high rates on the longer slant ranges to areostationary altitude will require steered, high-gain links. Both RF and optical options exist for achieving data rates in excess of 100 Mb/s. Several point designs offer a measure of potential user burden, in terms of mass, volume, power, and pointing requirements for user relay payloads, as a function of desired proximity link performance.

Simple approach to superhydrophobic nanostructured Al for practical antifrosting application based on enhanced self-propelled jumping droplets.

PubMed

Kim, Aeree; Lee, Chan; Kim, Hyungmo; Kim, Joonwon

2015-04-08

Frost formation can cause operational difficulty and efficiency loss for many facilities such as aircraft, wind turbines, and outdoor heat exchangers. Self-propelled jumping by condensate droplets on superhydrophobic surfaces delays frost formation, so many attempts have been made to exploit this phenomenon. However, practical application of this phenomenon is currently unfeasible because many processes to fabricate the superhydrophobic surfaces are inefficient and because self-propelled jumping is difficult to be achieved in a humid and low-temperature environment because superhydrophobicity is degraded in these conditions. Here, we achieved significantly effective anti-icing superhydrophobic aluminum. Its extremely low adhesive properties allow self-propelled jumping under highly supersaturated conditions of high humidity or low surface temperature. As a result, this surface helps retard frost formation at that condition. The aluminum was made superhydrophobic by a simple and cost-effective process that is adaptable to any shape. Therefore, it has promise for use in practical and industrial applications.

Maximising Longwall performance and profitability by the introduction of moving car bunker systems into outbye haulage layouts

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

Barlow, P.M.

1996-12-31

In order to maximize the profitability of Longwall mining operations, outbye materials handling systems should be cost effectively engineered to both fully harmonize with cyclical surges in output and to maintain high levels of availability. With the introduction of new Longwall systems into existing mines, the upgrading of outbye haulage to handle peak production from the Longwall panel can prove to be extremely expensive and is often unnecessary. In addition, despite high levels of investment in new equipment, many mines are still failing to achieve planned gains in Longwall productivity due to persistent downtime on outbye haulage routes. This papermore » details the planning, production and engineering considerations necessary to maximize profitability by the introduction of moving car bunker systems to underground haulage layouts. It also examines case studies of recent installations within the North American coal mining industry and charts the significant success being achieved in improving profitability at these mines.« less

Cellulose nanofiber extraction from grass by a modified kitchen blender

NASA Astrophysics Data System (ADS)

Nakagaito, Antonio Norio; Ikenaga, Koh; Takagi, Hitoshi

2015-03-01

Cellulose nanofibers have been used to reinforce polymers, delivering composites with strength that in some cases can be superior to that of engineering plastics. The extraction of nanofibers from plant fibers can be achieved through specialized equipment that demands high energy input, despite delivering extremely low yields. The high extraction cost confines the use of cellulose nanofibers to the laboratory and not for industrial applications. This study aims to extract nanofibers from grass by using a kitchen blender. Earlier studies have demonstrated that paper sheets made of blender-extracted nanofibers (after 5 min to 10 min of blending) have strengths on par with paper sheets made from commercially available cellulose nanofibers. By optimizing the design of the blender bottle, nanofibrillation can be achieved in shorter treatment times, reducing the energy consumption (in the present case, to half) and the overall extraction cost. The raw materials used can be extended to the residue straw of agricultural crops, as an alternative to the usual pulp fibers obtained from wood.

Nanocrystalline coating design for extreme applications based on the concept of complex adaptive behavior

NASA Astrophysics Data System (ADS)

Fox-Rabinovich, G. S.; Veldhuis, S. C.; Dosbaeva, G. K.; Yamamoto, K.; Kovalev, A. I.; Wainstein, D. L.; Gershman, I. S.; Shuster, L. S.; Beake, B. D.

2008-04-01

The development of effective hard coatings for high performance dry machining, which is associated with high stress/temperatures during friction, is a major challenge. Newly developed synergistically alloyed nanocrystalline adaptive Ti0.2Al0.55Cr0.2Si0.03Y0.02N plasma vapor deposited hard coatings exhibit excellent tool life under conditions of high performance dry machining of hardened steel, especially under severe and extreme cutting conditions. The coating is capable of sustaining cutting speeds as high as 600 m/min. Comprehensive investigation of the microstructure and properties of the coating was performed. The structure of the coating before and after service has been characterized by high resolution transmission electron microscopy. Micromechanical characteristics of the coating have been investigated at elevated temperatures. Oxidation resistance of the coating has been studied by using thermogravimetry within a temperature range of 25-1100 °C in air. The coefficient of friction of the coatings was studied within a temperature range of 25-1200 °C. To determine the causes of excellent tool life and improved wear behavior of the TiAlCrSiYN coatings, its surface structure characteristics after service have been investigated by using x-ray photoelectron spectroscopy and extended energy-loss fine spectroscopy. One of the major features of this coating is the dynamic formation of the protective tribo-oxide films (dissipative structures) on the surface during friction with a sapphire and mullite crystal structure. Aluminum- and silicon-rich tribofilms with dangling bonds form on the surface as well. These tribofilms act in synergy and protect the surface so efficiently that it is able to sustain extreme operating conditions. Moreover, the Ti0.2Al0.55Cr0.2Si0.03Y0.02N coating possesses some features of a complex adaptive behavior because it has a number of improved characteristics (tribological adaptability, ultrafine nanocrystalline structure, hot hardness and plasticity, and oxidation stability) that work synergistically as a whole. Due to the complex adaptive behavior, this coating represents a higher ordered system that has an ability to achieve unattainable wear resistance under strongly intensifying and extreme tribological conditions.

Coupled hydro-meteorological modelling on a HPC platform for high-resolution extreme weather impact study

NASA Astrophysics Data System (ADS)

Zhu, Dehua; Echendu, Shirley; Xuan, Yunqing; Webster, Mike; Cluckie, Ian

2016-11-01

Impact-focused studies of extreme weather require coupling of accurate simulations of weather and climate systems and impact-measuring hydrological models which themselves demand larger computer resources. In this paper, we present a preliminary analysis of a high-performance computing (HPC)-based hydrological modelling approach, which is aimed at utilizing and maximizing HPC power resources, to support the study on extreme weather impact due to climate change. Here, four case studies are presented through implementation on the HPC Wales platform of the UK mesoscale meteorological Unified Model (UM) with high-resolution simulation suite UKV, alongside a Linux-based hydrological model, Hydrological Predictions for the Environment (HYPE). The results of this study suggest that the coupled hydro-meteorological model was still able to capture the major flood peaks, compared with the conventional gauge- or radar-driving forecast, but with the added value of much extended forecast lead time. The high-resolution rainfall estimation produced by the UKV performs similarly to that of radar rainfall products in the first 2-3 days of tested flood events, but the uncertainties particularly increased as the forecast horizon goes beyond 3 days. This study takes a step forward to identify how the online mode approach can be used, where both numerical weather prediction and the hydrological model are executed, either simultaneously or on the same hardware infrastructures, so that more effective interaction and communication can be achieved and maintained between the models. But the concluding comments are that running the entire system on a reasonably powerful HPC platform does not yet allow for real-time simulations, even without the most complex and demanding data simulation part.

The Extreme Ultraviolet spectrometer on bard the Hisaki satellite

NASA Astrophysics Data System (ADS)

Yoshioka, K.; Murakami, G.; Yamazaki, A.; Tsuchiya, F.; Kagitani, M.; Kimura, T.; Yoshikawa, I.

2017-12-01

The extreme ultraviolet spectroscope EXCEED (EXtrem ultraviolet spetrosCope for ExosphEric Dynamics) on board the Hisaki satellite was launched in September 2013 from the Uchinoura space center, Japan. It is orbiting around the Earth with an orbital altitude of around 950-1150 km. This satellite is dedicated to and optimized for observing the atmosphere and magnetosphere of terrestrial planets such as Mercury, Venus, Mars, as well as Jupiter. The instrument consists of an off axis parabolic entrance mirror, switchable slits with multiple filters and shapes, a toroidal grating, and a photon counting detector, together with a field of view guiding camera. The design goal is to achieve a large effective area but with high spatial and spectral resolution. Based on the after-launch calibration, the spectral resolution of EXCEED is found to be 0.3-0.5 nm FWHM (Full Width at Half Maximum) over the entire spectral band, and the spatial resolution is around 17". The evaluated effective area is larger than 1cm2. In this presentation, the basic concept of the instrument design and the observation technique are introduced. The current status of the spacecraft and its future observation plan are also shown.

Ferroelectric thin-film capacitors and piezoelectric switches for mobile communication applications.

PubMed

Klee, Mareike; van Esch, Harry; Keur, Wilco; Kumar, Biju; van Leuken-Peters, Linda; Liu, Jin; Mauczok, Rüdiger; Neumann, Kai; Reimann, Klaus; Renders, Christel; Roest, Aarnoud L; Tiggelman, Mark P J; de Wild, Marco; Wunnicke, Olaf; Zhao, Jing

2009-08-01

Thin-film ferroelectric capacitors have been integrated with resistors and active functions such as ESD protection into small, miniaturized modules, which enable a board space saving of up to 80%. With the optimum materials and processes, integrated capacitors with capacitance densities of up to 100 nF/mm2 for stacked capacitors combined with breakdown voltages of 90 V have been achieved. The integration of these high-density capacitors with extremely high breakdown voltage is a major accomplishment in the world of passive components and has not yet been reported for any other passive integration technology. Furthermore, thin-film tunable capacitors based on barium strontium titanate with high tuning range and high quality factor at 1 GHz have been demonstrated. Finally, piezoelectric thin films for piezoelectric switches with high switching speed have been realized.

Advanced RF and microwave functions based on an integrated optical frequency comb source.

PubMed

Xu, Xingyuan; Wu, Jiayang; Nguyen, Thach G; Shoeiby, Mehrdad; Chu, Sai T; Little, Brent E; Morandotti, Roberto; Mitchell, Arnan; Moss, David J

2018-02-05

We demonstrate advanced transversal radio frequency (RF) and microwave functions based on a Kerr optical comb source generated by an integrated micro-ring resonator. We achieve extremely high performance for an optical true time delay aimed at tunable phased array antenna applications, as well as reconfigurable microwave photonic filters. Our results agree well with theory. We show that our true time delay would yield a phased array antenna with features that include high angular resolution and a wide range of beam steering angles, while the microwave photonic filters feature high Q factors, wideband tunability, and highly reconfigurable filtering shapes. These results show that our approach is a competitive solution to implementing reconfigurable, high performance and potentially low cost RF and microwave signal processing functions for applications including radar and communication systems.

Highly stretchable carbon aerogels.

PubMed

Guo, Fan; Jiang, Yanqiu; Xu, Zhen; Xiao, Youhua; Fang, Bo; Liu, Yingjun; Gao, Weiwei; Zhao, Pei; Wang, Hongtao; Gao, Chao

2018-02-28

Carbon aerogels demonstrate wide applications for their ultralow density, rich porosity, and multifunctionalities. Their compressive elasticity has been achieved by different carbons. However, reversibly high stretchability of neat carbon aerogels is still a great challenge owing to their extremely dilute brittle interconnections and poorly ductile cells. Here we report highly stretchable neat carbon aerogels with a retractable 200% elongation through hierarchical synergistic assembly. The hierarchical buckled structures and synergistic reinforcement between graphene and carbon nanotubes enable a temperature-invariable, recoverable stretching elasticity with small energy dissipation (~0.1, 100% strain) and high fatigue resistance more than 10 6 cycles. The ultralight carbon aerogels with both stretchability and compressibility were designed as strain sensors for logic identification of sophisticated shape conversions. Our methodology paves the way to highly stretchable carbon and neat inorganic materials with extensive applications in aerospace, smart robots, and wearable devices.

Compact 200 kHz HHG source driven by a few-cycle OPCPA

NASA Astrophysics Data System (ADS)

Harth, Anne; Guo, Chen; Cheng, Yu-Chen; Losquin, Arthur; Miranda, Miguel; Mikaelsson, Sara; Heyl, Christoph M.; Prochnow, Oliver; Ahrens, Jan; Morgner, Uwe; L'Huillier, Anne; Arnold, Cord L.

2018-01-01

We present efficient high-order harmonic generation (HHG) based on a high-repetition rate, few-cycle, near infrared (NIR), carrier-envelope phase stable, optical parametric chirped pulse amplifier (OPCPA), emitting 6 fs pulses with 9 μJ pulse energy. In krypton, we reach conversion efficiencies from the NIR to the extreme ultraviolet (XUV) radiation pulse energy on the order of ˜10-6 with less than 3 μJ driving pulse energy. This is achieved by optimizing the OPCPA for a spatially and temporally clean pulse and by a specially designed high-pressure gas target. In the future, the high efficiency of the HHG source will be beneficial for high-repetition rate two-colour (NIR-XUV) pump-probe experiments, where the available pulse energy from the laser has to be distributed economically between pump and probe pulses.

Hierarchical adaptive nanostructured PVD coatings for extreme tribological applications: the quest for nonequilibrium states and emergent behavior.

PubMed

Fox-Rabinovich, German S; Yamamoto, Kenji; Beake, Ben D; Gershman, Iosif S; Kovalev, Anatoly I; Veldhuis, Stephen C; Aguirre, Myriam H; Dosbaeva, Goulnara; Endrino, Jose L

2012-08-01

Adaptive wear-resistant coatings produced by physical vapor deposition (PVD) are a relatively new generation of coatings which are attracting attention in the development of nanostructured materials for extreme tribological applications. An excellent example of such extreme operating conditions is high performance machining of hard-to-cut materials. The adaptive characteristics of such coatings develop fully during interaction with the severe environment. Modern adaptive coatings could be regarded as hierarchical surface-engineered nanostructural materials. They exhibit dynamic hierarchy on two major structural scales: (a) nanoscale surface layers of protective tribofilms generated during friction and (b) an underlying nano/microscaled layer. The tribofilms are responsible for some critical nanoscale effects that strongly impact the wear resistance of adaptive coatings. A new direction in nanomaterial research is discussed: compositional and microstructural optimization of the dynamically regenerating nanoscaled tribofilms on the surface of the adaptive coatings during friction. In this review we demonstrate the correlation between the microstructure, physical, chemical and micromechanical properties of hard coatings in their dynamic interaction (adaptation) with environment and the involvement of complex natural processes associated with self-organization during friction. Major physical, chemical and mechanical characteristics of the adaptive coating, which play a significant role in its operating properties, such as enhanced mass transfer, and the ability of the layer to provide dissipation and accumulation of frictional energy during operation are presented as well. Strategies for adaptive nanostructural coating design that enhance beneficial natural processes are outlined. The coatings exhibit emergent behavior during operation when their improved features work as a whole. In this way, as higher-ordered systems, they achieve multifunctionality and high wear resistance under extreme tribological conditions.

Hierarchical adaptive nanostructured PVD coatings for extreme tribological applications: the quest for nonequilibrium states and emergent behavior

PubMed Central

Fox-Rabinovich, German S; Yamamoto, Kenji; Beake, Ben D; Gershman, Iosif S; Kovalev, Anatoly I; Veldhuis, Stephen C; Aguirre, Myriam H.; Dosbaeva, Goulnara; Endrino, Jose L

2012-01-01

Adaptive wear-resistant coatings produced by physical vapor deposition (PVD) are a relatively new generation of coatings which are attracting attention in the development of nanostructured materials for extreme tribological applications. An excellent example of such extreme operating conditions is high performance machining of hard-to-cut materials. The adaptive characteristics of such coatings develop fully during interaction with the severe environment. Modern adaptive coatings could be regarded as hierarchical surface-engineered nanostructural materials. They exhibit dynamic hierarchy on two major structural scales: (a) nanoscale surface layers of protective tribofilms generated during friction and (b) an underlying nano/microscaled layer. The tribofilms are responsible for some critical nanoscale effects that strongly impact the wear resistance of adaptive coatings. A new direction in nanomaterial research is discussed: compositional and microstructural optimization of the dynamically regenerating nanoscaled tribofilms on the surface of the adaptive coatings during friction. In this review we demonstrate the correlation between the microstructure, physical, chemical and micromechanical properties of hard coatings in their dynamic interaction (adaptation) with environment and the involvement of complex natural processes associated with self-organization during friction. Major physical, chemical and mechanical characteristics of the adaptive coating, which play a significant role in its operating properties, such as enhanced mass transfer, and the ability of the layer to provide dissipation and accumulation of frictional energy during operation are presented as well. Strategies for adaptive nanostructural coating design that enhance beneficial natural processes are outlined. The coatings exhibit emergent behavior during operation when their improved features work as a whole. In this way, as higher-ordered systems, they achieve multifunctionality and high wear resistance under extreme tribological conditions. PMID:27877499

Development of a New Generation of Stable, Tunable, and Catalytically Active Nanoparticles Produced by the Helium Nanodroplet Deposition Method

DOE PAGES

Wu, Qiyuan; Ridge, Claron J.; Zhao, Shen; ...

2016-07-13

Nanoparticles (NPs) are revolutionizing many areas of science and technology, often delivering unprecedented improvements to properties of the conventional materials. However, despite important advances in NPs synthesis and applications, numerous challenges still remain. Development of alternative synthetic method capable of producing very uniform, extremely clean and very stable NPs is urgently needed. If successful, such method can potentially transform several areas of nanoscience, including environmental and energy related catalysis. Here we present the first experimental demonstration of catalytically active NPs synthesis achieved by the helium nanodroplet isolation method. This alternative method of NPs fabrication and deposition produces narrowly distributed, clean,more » and remarkably stable NPs. The fabrication is achieved inside ultra-low temperature, superfluid helium nanodroplets, which can be subsequently deposited onto any substrate. Lastly, this technique is universal enough to be applied to nearly any element, while achieving high deposition rates for single element as well as composite core-shell NPs.« less

Radiofrequency Ablation Followed by Percutaneous Ethanol Ablation Leading to Long-Term Remission of Hyperparathyroidism

PubMed Central

Menon, Arun S.; Nazar, P. K.; Moorthy, Srikanth; Kumar, Harish; Nair, Vasantha; Pavithran, Praveen Valiyaparambil; Bhavani, Nisha; Menon, Vadayath Usha; Abraham, Nithya; Jayakumar, R. Vasukutty

2017-01-01

A 30-year-old male with cerebral palsy and motor impairment presented with right femur fracture. He had gradually worsening mobility and contractures of all extremities for the preceding 5 years. Evaluation showed multiple vertebral and femoral fractures, severe osteoporosis, a large parathyroid adenoma, and parathormone (PTH) exceeding 2500 pg/mL. Because of poor general health and high anesthetic risk, parathyroidectomy was deemed impractical. Ultrasound-guided radiofrequency ablation (RFA) helped achieve 50% size reduction and PTH levels with better control of hypercalcemia. Later, as calcium and PTH remained elevated, percutaneous ethanol ablation was performed with resultant normalization of PTH and substantial symptomatic improvement. Two years later, he still remains normocalcaemic with normal PTH levels. We propose that RFA and percutaneous ethanol ablation be considered as effective short-term options for surgically difficult cases, which could even help achieve long-term remission. Although not previously reported, our case illustrates that both RFA and percutaneous ethanol ablation could be safely performed successively achieving long-term remission. PMID:29264521

How many familial hypercholesterolemia patients are eligible for PCSK9 inhibition?

PubMed

Masana, Luis; Plana, Nuria; Pérez-Calahorra, Sofia; Ibarretxe, Daiana; Lamiquiz-Moneo, Itziar; Pedro-Botet, Juan; Suárez-Tembra, Manuel; Valdivielso, Pedro; Ortega, Emilio; Civeira, Fernando

2017-07-01

Familial hypercholesterolemia (FH) is a high cardiovascular risk condition. Less than 20% of patients achieve the LDL targets. Although PCSK9 inhibitors improve control and reduce cardiovascular events, official recommendations for their use are restrictive. We aim to assess the number of FH patients suitable for PCSK9 inhibition according to the European guidelines. A total of 2685 FH patients, with a minimum follow-up of 6 months, included in the Dyslipidemia Registry of the Spanish Arteriosclerosis Society, were sorted according to the intensity of their lipid-lowering therapy (LLT) and LDL cholesterol levels achieved. The number of patients who met the recommendations for PCSK9 inhibition treatment according to the European Atherosclerosis Society (ESC/EAS), Spanish Arteriosclerosis Society and the European Medicines Agency was calculated. In total, 1573 patients were on high-intensity LLT; 607 were on moderate-intensity statins; 82 were on low-intensity LLT, and 423 were neither on statins nor on ezetimibe in the last visit registered. The mean LDL reduction among those on high-intensity LLT was 54%. Ninety-one percent of patients on high-intensity LLT had an LDL below 5.2 mmol/L, 53% below 3.4 mmol/L, and 23% below 2.6 mmol/L. Only 12% of FH patients with cardiovascular disease achieved 1.8 mmol/L. Despite this, only 17% of patients qualified for PCSK9 inhibition according to ESC/EAS guidelines. For patients with a condition that exposes them to high cardiovascular risk and who have extreme difficulties in achieving LDL targets, wider access to PCSK9 inhibitor therapy is warranted. Copyright © 2017 Elsevier B.V. All rights reserved.

Initial performance results for high-aspect ratio gold MEMS deformable mirrors

NASA Astrophysics Data System (ADS)

Fernández, Bautista; Kubby, Joel

2009-02-01

The fabrication and initial performance results of high-aspect ratio 3-dimensional Micro-Electro-Mechanical System (MEMS) Deformable Mirrors (DM) for Adaptive Optics (AO) will be discussed. The DM systems were fabricated out of gold, and consist of actuators bonded to a continuous face sheet, with different boundary conditions. DM mirror displacements vs. voltage have been measured with a white light interferometer and the corresponding results compared to Finite Element Analysis (FEA) simulations. Interferometer scans of a DM have shown that ~9.4um of stroke can be achieved with low voltage, thus showing that this fabrication process holds promise in the manufacturing of future MEMS DM's for the next generation of extremely large telescopes.

Ultra-efficient all-printed organic photodetectors

NASA Astrophysics Data System (ADS)

Kielar, Marcin; Dhez, Olivier; Hirsch, Lionel

2016-09-01

Organic photodetectors are able to transform plastic into intelligent surfaces making our daily life easier, smarter and more productive. The key element for a sensor is to reduce the dark current density in order to boost the limit of detection. The energetic requirements in order to select materials for ultra-high performance organic photodetectors are presented with the following experimental results: a detectivity of 3.36 × 1013 Jones has been achieved with an extremely low dark current density of 0.32 nA cm-2 and a responsivity as high as 0.34 A W-1. Flexible devices are all made at lowtemperature and with solution-processed materials. Their stability under operation is also presented.

A narrow open tubular column for high efficiency liquid chromatographic separation.

PubMed

Chen, Huang; Yang, Yu; Qiao, Zhenzhen; Xiang, Piliang; Ren, Jiangtao; Meng, Yunzhu; Zhang, Kaiqi; Juan Lu, Joann; Liu, Shaorong

2018-04-30

We report a great feature of open tubular liquid chromatography when it is run using an extremely narrow (e.g., 2 μm inner diameter) open tubular column: more than 10 million plates per meter can be achieved in less than 10 min and under an elution pressure of ca. 20 bar. The column is coated with octadecylsilane and both isocratic and gradient separations are performed. We reveal a focusing effect that may be used to interpret the efficiency enhancement. We also demonstrate the feasibility of using this technique for separating complex peptide samples. This high-resolution and fast separation technique is promising and can lead to a powerful tool for trace sample analysis.

Learning Problems in Kindergarten Students with Extremely Preterm Birth

PubMed Central

Taylor, H. Gerry; Klein, Nancy; Anselmo, Marcia G.; Minich, Nori; Espy, Kimberly A.; Hack, Maureen

2012-01-01

Objective To assess learning problems in extremely preterm children in kindergarten and identify risk factors. Design Cohort study. Setting Children’s hospital. Participants A cohort of extremely preterm children born January 2001 – December 2003 (n=148), defined as <28 weeks gestation and/or <1000 g birth weight, and term-born normal birth weight classmate controls (n=111). Main Interventions The children were enrolled during their first year in kindergarten and assessed on measures of learning progress. Main Outcome Measures Achievement testing, teacher ratings of learning progress, and individual educational assistance. Results The extremely preterm children had lower mean standard scores than controls on tests of spelling (8.52 points, 95% CI: 4.58, 12.46) and applied mathematics (11.02 points, 95% CI: 6.76, 15.28). They also had higher rates of substandard learning progress by teacher report in written language (OR = 4.23, 95% CI: 2.32, 7.73) and mathematics (OR = 7.08, 95% CI: 2.79, 17.95). Group differences on mathematics achievement and in teacher ratings of learning progress were significant even in children without neurosensory deficits or low global cognitive ability. Neonatal risk factors, early childhood neurodevelopmental impairment, and socioeconomic status predicted learning problems in extremely preterm children, yet many of the children with problems were not in a special education program. Conclusion Learning problems in extremely preterm children are evident in kindergarten and are associated with neonatal and early childhood risk factors. The findings support efforts to provide more extensive monitoring and interventions both prior to and during the first year in school. PMID:21893648

Combination of a total free forearm flap and a sensate local flap for preservation of the shoulder girdle in massive, nonreplantable upper extremity injuries.

PubMed

Jakubietz, Rafael G; Jakubietz, Michael G; Kloss, Danni F; Gruenert, Joerg G

2009-02-01

After massive upper extremity injuries, prosthetic use might be complicated by the formation of pressure ulcerations. Especially the coverage with insensate free flaps may predispose the patient for developing chronic ulcerations when using an upper extremity prosthesis. This complication may be reduced when sensate local flaps are used to cover bony prominences. A new operative technique is described. Immediate sensate soft tissue coverage improves prosthetic fitting. Successful manipulation of the prosthesis can be quickly achieved with a decreased risk for pressure ulceration. This challenging procedure helps to achieve durable and sensate coverage of bony prominences. The use of local sensate tissue to cover bony prominences reduces the risk for pressure ulceration when wearing a prosthesis. Areas where prosthetic use causes only low pressure and shearing forces are adequately covered with free flaps. Immediate sensibility of local flaps allows prosthetic fitting and use as soon as wound healing has occurred. Return to work is thus expedited.

Grain Yield and Water Use Efficiency in Extremely-Late Sown Winter Wheat Cultivars under Two Irrigation Regimes in the North China Plain

PubMed Central

Wang, Bin; Zhang, Yinghua; Hao, Baozhen; Xu, Xuexin; Zhao, Zhigan; Wang, Zhimin; Xue, Qingwu

2016-01-01

Wheat production is threatened by water shortages and groundwater over-draft in the North China Plain (NCP). In recent years, winter wheat has been increasingly sown extremely late in early to mid-November after harvesting cotton or pepper. To improve water use efficiency (WUE) and guide the extremely late sowing practices, a 3-year field experiment was conducted under two irrigation regimes (W1, one-irrigation, 75 mm at jointing; W2, two-irrigation, 75 mm at jointing and 75 mm at anthesis) in 3 cultivars differing in spike size (HS4399, small spike; JM22, medium spike; WM8, large spike). Wheat was sown in early to mid-November at a high seeding rate of 800–850 seeds m−2. Average yields of 7.42 t ha−1 and WUE of 1.84 kg m−3 were achieved with an average seasonal evapotranspiration (ET) of 404 mm. Compared with W2, wheat under W1 did not have yield penalty in 2 of 3 years, and had 7.9% lower seasonal ET and 7.5% higher WUE. The higher WUE and stable yield under W1 was associated with higher 1000-grain weight (TGW) and harvest index (HI). Among the 3 cultivars, JM22 had 5.9%–8.9% higher yield and 4.2%–9.3% higher WUE than WM8 and HS4399. The higher yield in JM22 was attributed mainly to higher HI and TGW due to increased post-anthesis biomass and deeper seasonal soil water extraction. In conclusion, one-irrigation with a medium-sized spike cultivar JM22 could be a useful strategy to maintain yield and high WUE in extremely late-sown winter wheat at a high seeding rate in the NCP. PMID:27100187

Extreme drought alters frequency and reproductive success of floaters in Willow Flycatchers

USGS Publications Warehouse

Theimer, Tad; Sogge, Mark K.; Cardinal, Suzanne N.; Durst, Scott L.; Paxton, Eben H.

2018-01-01

Changes in habitat quality, including those caused by extreme events like droughts and floods, could alter costs and benefits of territoriality and thereby the prevalence and reproductive consequences for individuals capable of breeding that do not do so (floaters). We studied floating behavior in a population of Southwestern Willow Flycatchers (Empidonax traillii extimus) in central Arizona during one year of extreme drought, one year of lake inundation, and three years of near average precipitation. In all years, most floaters were second year (SY) males, and most subsequently settled outside of the patch where they were detected in the floating year, suggesting that floaters did not “queue” at high-quality territories in order to achieve higher reproductive success in subsequent years. Instead, cohorts that floated in non-drought years had lower apparent survival and lower reproductive success compared to territorial birds. In the extreme drought year, however, the number of floaters was 1.5 times greater than in all other years combined, more females floated, and apparent survival and mean annual productivity in subsequent years was higher for males that floated in that year than for those that were territorial. Inundation of habitat due to rising reservoir levels did not result in an increase in floaters because many birds nested in inundated areas where trees projected above the water so that the relative amount of available habitat was not reduced to the extent habitat models predicted. Overall, our results indicate that the prevalence and reproductive and demographic consequences of floating can change under extreme climatic events like severe drought.

Toward Generation of High Power Ultrafast White Light Laser Using Femtosecond Terawatt Laser in a Gas-Filled Hollow-Core Fiber

NASA Astrophysics Data System (ADS)

Tawfik, Walid

2015-06-01

In this work, we could experimentally achieved the generation of white-light laser pulses of few-cycle fs pulses using a neon-filled hollow-core fiber. The observed pulses reached 6-fs at at repetition rate of 1 kHz using 2.5 mJ of 31 fs femtosecond pulses. The pulse compressing achieved by the supercontinuum produced in static neon-filled hollow fibers while the dispersion compensation is achieved by five pairs of chirped mirrors. We showed that gas pressure can be used to continuously vary the bandwidth from 350 nm to 900 nm. Furthermore, the applied technique allows for a straightforward tuning of the pulse duration via the gas pressure whilst maintaining near-transform-limited pulses with constant output energy, thereby reducing the complications introduced by chirped pulses. Through measurements of the transmission through the fiber as a function of gas pressure, a high throughput exceeding 60% was achieved. Adaptive pulse compression is achieved by using the spectral phase obtained from a spectral phase interferometry for direct electric field reconstruction (SPIDER) measurement as feedback for a liquid crystal spatial light modulator (SLM). The spectral phase of these supercontinua is found to be extremely stable over several hours. This allowed us to demonstrate successful compression to pulses as short as 5.2 fs with controlled wide spectral bandwidth, which could be used to excite different states in complicated molecules at once.

Experiments in structural dynamics and control using a grid

NASA Technical Reports Server (NTRS)

Montgomery, R. C.

1985-01-01

Future spacecraft are being conceived that are highly flexible and of extreme size. The two features of flexibility and size pose new problems in control system design. Since large scale structures are not testable in ground based facilities, the decision on component placement must be made prior to full-scale tests on the spacecraft. Control law research is directed at solving problems of inadequate modelling knowledge prior to operation required to achieve peak performance. Another crucial problem addressed is accommodating failures in systems with smart components that are physically distributed on highly flexible structures. Parameter adaptive control is a method of promise that provides on-orbit tuning of the control system to improve performance by upgrading the mathematical model of the spacecraft during operation. Two specific questions are answered in this work. They are: What limits does on-line parameter identification with realistic sensors and actuators place on the ultimate achievable performance of a system in the highly flexible environment? Also, how well must the mathematical model used in on-board analytic redundancy be known and what are the reasonable expectations for advanced redundancy management schemes in the highly flexible and distributed component environment?

Tamm-plasmon and surface-plasmon hybrid-mode based refractometry in photonic bandgap structures.

PubMed

Das, Ritwick; Srivastava, Triranjita; Jha, Rajan

2014-02-15

The transverse magnetic (TM) polarized hybrid modes formed as a consequence of coupling between Tamm plasmon polariton (TM-TPP) mode and surface plasmon polariton (SPP) mode exhibit interesting dispersive features for realizing a highly sensitive and accurate surface plasmon resonance (SPR) sensor. We found that the TM-TPP modes, formed at the interface of distributed Bragg reflector and metal, are strongly dispersive as compared to SPP modes at optical frequencies. This causes an appreciably narrow interaction bandwidth between TM-TPP and SPP modes, which leads to highly accurate sensing. In addition, appropriate tailoring of dispersion characteristics of TM-TPP as well as SPP modes could ensure high sensitivity of a novel SPR platform. By suitably designing the Au/TiO₂/SiO₂-based geometry, we propose a TM-TPP/SPP hybrid-mode sensor and achieve a sensitivity ≥900  nm/RIU with high detection accuracy (≥30  μm⁻¹) for analyte refractive indices varying between 1.330 and 1.345 in 600-700 nm wavelength range. The possibility to achieve desired dispersive behavior in any spectral band makes the sensing configuration an extremely attractive candidate to design sensors depending on the availability of optical sources.

Vacuum-Ultraviolet Photovoltaic Detector.

PubMed

Zheng, Wei; Lin, Richeng; Ran, Junxue; Zhang, Zhaojun; Ji, Xu; Huang, Feng

2018-01-23

Over the past two decades, solar- and astrophysicists and material scientists have been researching and developing new-generation semiconductor-based vacuum ultraviolet (VUV) detectors with low power consumption and small size for replacing traditional heavy and high-energy-consuming microchannel-detection systems, to study the formation and evolution of stars. However, the most desirable semiconductor-based VUV photovoltaic detector capable of achieving zero power consumption has not yet been achieved. With high-crystallinity multistep epitaxial grown AlN as a VUV-absorbing layer for photogenerated carriers and p-type graphene (with unexpected VUV transmittance >96%) as a transparent electrode to collect excited holes, we constructed a heterojunction device with photovoltaic detection for VUV light. The device exhibits an encouraging VUV photoresponse, high external quantum efficiency (EQE) and extremely fast tempera response (80 ns, 10 4 -10 6 times faster than that of the currently reported VUV photoconductive devices). This work has provided an idea for developing zero power consumption and integrated VUV photovoltaic detectors with ultrafast and high-sensitivity VUV detection capability, which not only allows future spacecraft to operate with longer service time and lower launching cost but also ensures an ultrafast evolution of interstellar objects.

Advances in Glass Formulations for Hanford High-Aluminum, High-Iron and Enhanced Sulphate Management in HLW Streams - 13000

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

Kruger, Albert A.

2013-07-01

The current estimates and glass formulation efforts have been conservative in terms of achievable waste loadings. These formulations have been specified to ensure that the glasses are homogenous, contain essentially no crystalline phases, are processable in joule-heated, ceramic-lined melters and meet Hanford Tank Waste Treatment and Immobilization Plant (WTP) Contract terms. The WTP's overall mission will require the immobilization of tank waste compositions that are dominated by mixtures of aluminum (Al), chromium (Cr), bismuth (Bi), iron (Fe), phosphorous (P), zirconium (Zr), and sulphur (S) compounds as waste-limiting components. Glass compositions for these waste mixtures have been developed based upon previousmore » experience and current glass property models. Recently, DOE has initiated a testing program to develop and characterize HLW glasses with higher waste loadings and higher throughput efficiencies. Results of this work have demonstrated the feasibility of increases in waste loading from about 25 wt% to 33-50 wt% (based on oxide loading) in the glass depending on the waste stream. In view of the importance of aluminum limited waste streams at Hanford (and also Savannah River), the ability to achieve high waste loadings without adversely impacting melt rates has the potential for enormous cost savings from reductions in canister count and the potential for schedule acceleration. Consequently, the potential return on the investment made in the development of these enhancements is extremely favorable. Glass composition development for one of the latest Hanford HLW projected compositions with sulphate concentrations high enough to limit waste loading have been successfully tested and show tolerance for previously unreported tolerance for sulphate. Though a significant increase in waste loading for high-iron wastes has been achieved, the magnitude of the increase is not as substantial as those achieved for high-aluminum, high-chromium, high-bismuth or sulphur. Waste processing rate increases for high-iron streams as a combined effect of higher waste loadings and higher melt rates resulting from new formulations have been achieved. (author)« less

Advances in Glass Formulations for Hanford High-Alumimum, High-Iron and Enhanced Sulphate Management in HLW Streams - 13000

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

Kruger, Albert A.

2013-01-16

The current estimates and glass formulation efforts have been conservative in terms of achievable waste loadings. These formulations have been specified to ensure that the glasses are homogenous, contain essentially no crystalline phases, are processable in joule-heated, ceramic-lined melters and meet Hanford Tank Waste Treatment and Immobilization Plant (WTP) Contract terms. The WTP?s overall mission will require the immobilization of tank waste compositions that are dominated by mixtures of aluminum (Al), chromium (Cr), bismuth (Bi), iron (Fe), phosphorous (P), zirconium (Zr), and sulphur (S) compounds as waste-limiting components. Glass compositions for these waste mixtures have been developed based upon previousmore » experience and current glass property models. Recently, DOE has initiated a testing program to develop and characterize HLW glasses with higher waste loadings and higher throughput efficiencies. Results of this work have demonstrated the feasibility of increases in waste loading from about 25 wt% to 33-50 wt% (based on oxide loading) in the glass depending on the waste stream. In view of the importance of aluminum limited waste streams at Hanford (and also Savannah River), the ability to achieve high waste loadings without adversely impacting melt rates has the potential for enormous cost savings from reductions in canister count and the potential for schedule acceleration. Consequently, the potential return on the investment made in the development of these enhancements is extremely favorable. Glass composition development for one of the latest Hanford HLW projected compositions with sulphate concentrations high enough to limit waste loading have been successfully tested and show tolerance for previously unreported tolerance for sulphate. Though a significant increase in waste loading for high-iron wastes has been achieved, the magnitude of the increase is not as substantial as those achieved for high-aluminum, high-chromium, high-bismuth or sulphur. Waste processing rate increases for high-iron streams as a combined effect of higher waste loadings and higher melt rates resulting from new formulations have been achieved.« less

Learning to Read Against All Odds: Using Precision Reading to Enhance Literacy in Students with Cognitive Impairments, Extreme Academic Deficits, and Severe Social, Emotional, and Psychiatric Problems

ERIC Educational Resources Information Center

Freeze, Rick; Cook, Paula

2005-01-01

The purpose of this study was to assess the efficacy and practicality of precision reading, a constructive reading intervention, with students with cognitive impairments, extreme academic deficits in reading, and severe social, emotional, and psychiatric problems. As precision reading had shown promise with students with low achievement, learning…

Modeling high-efficiency extreme ultraviolet etched multilayer phase-shift masks

NASA Astrophysics Data System (ADS)

Sherwin, Stuart; Neureuther, Andrew; Naulleau, Patrick

2017-10-01

Achieving high-throughput extreme ultraviolet (EUV) patterning remains a major challenge due to low source power; phase-shift masks can help solve this challenge for dense features near the resolution limit by creating brighter images than traditional absorber masks when illuminated with the same source power. We explore applications of etched multilayer phase-shift masks for EUV lithography, both in the current-generation 0.33 NA and next-generation 0.55 NA systems. We derive analytic formulas for the thin-mask throughput gains, which are 2.42× for lines and spaces and 5.86× for contacts compared with an absorber mask with dipole and quadrupole illumination, respectively. Using rigorous finite-difference time-domain simulations, we quantify variations in these gains by pitch and orientation, finding 87% to 113% of the thin-mask value for lines and spaces and a 91% to 99% for contacts. We introduce an edge placement error metric, which accounts for CD errors, relative feature motion, and telecentricity errors, and use this metric both to optimize mask designs for individual features and to explore which features can be printed on the same mask. Furthermore, we find that although partial coherence shrinks the process window, at an achievable sigma of 0.2 we obtain a depth of focus of 340 nm and an exposure latitude of 39.2%, suggesting that partial coherence will not limit the feasibility of this technology. Finally, we show that many problems such as sensitivity to etch uniformity can be greatly mitigated using a central obscuration in the imaging pupil.

High-Precision Distribution of Highly Stable Optical Pulse Trains with 8.8 × 10−19 instability

PubMed Central

Ning, B.; Zhang, S. Y.; Hou, D.; Wu, J. T.; Li, Z. B.; Zhao, J. Y.

2014-01-01

The high-precision distribution of optical pulse trains via fibre links has had a considerable impact in many fields. In most published work, the accuracy is still fundamentally limited by unavoidable noise sources, such as thermal and shot noise from conventional photodiodes and thermal noise from mixers. Here, we demonstrate a new high-precision timing distribution system that uses a highly precise phase detector to obviously reduce the effect of these limitations. Instead of using photodiodes and microwave mixers, we use several fibre Sagnac-loop-based optical-microwave phase detectors (OM-PDs) to achieve optical-electrical conversion and phase measurements, thereby suppressing the sources of noise and achieving ultra-high accuracy. The results of a distribution experiment using a 10-km fibre link indicate that our system exhibits a residual instability of 2.0 × 10−15 at1 s and8.8 × 10−19 at 40,000 s and an integrated timing jitter as low as 3.8 fs in a bandwidth of 1 Hz to 100 kHz. This low instability and timing jitter make it possible for our system to be used in the distribution of optical-clock signals or in applications that require extremely accurate frequency/time synchronisation. PMID:24870442

The contribution of visual processing to academic achievement in adolescents born extremely preterm or extremely low birth weight.

PubMed

Molloy, Carly S; Di Battista, Ashley M; Anderson, Vicki A; Burnett, Alice; Lee, Katherine J; Roberts, Gehan; Cheong, Jeanie Ly; Anderson, Peter J; Doyle, Lex W

2017-04-01

Children born extremely preterm (EP, <28 weeks) and/or extremely low birth weight (ELBW, <1000 g) have more academic deficiencies than their term-born peers, which may be due to problems with visual processing. The aim of this study is to determine (1) if visual processing is related to poor academic outcomes in EP/ELBW adolescents, and (2) how much of the variance in academic achievement in EP/ELBW adolescents is explained by visual processing ability after controlling for perinatal risk factors and other known contributors to academic performance, particularly attention and working memory. A geographically determined cohort of 228 surviving EP/ELBW adolescents (mean age 17 years) was studied. The relationships between measures of visual processing (visual acuity, binocular stereopsis, eye convergence, and visual perception) and academic achievement were explored within the EP/ELBW group. Analyses were repeated controlling for perinatal and social risk, and measures of attention and working memory. It was found that visual acuity, convergence and visual perception are related to scores for academic achievement on univariable regression analyses. After controlling for potential confounds (perinatal and social risk, working memory and attention), visual acuity, convergence and visual perception remained associated with reading and math computation, but only convergence and visual perception are related to spelling. The additional variance explained by visual processing is up to 6.6% for reading, 2.7% for spelling, and 2.2% for math computation. None of the visual processing variables or visual motor integration are associated with handwriting on multivariable analysis. Working memory is generally a stronger predictor of reading, spelling, and math computation than visual processing. It was concluded that visual processing difficulties are significantly related to academic outcomes in EP/ELBW adolescents; therefore, specific attention should be paid to academic remediation strategies incorporating the management of working memory and visual processing in EP/ELBW children.

Solar thermoelectric generator

DOEpatents

Toberer, Eric S.; Baranowski, Lauryn L.; Warren, Emily L.

2016-05-03

Solar thermoelectric generators (STEGs) are solid state heat engines that generate electricity from concentrated sunlight. A novel detailed balance model for STEGs is provided and applied to both state-of-the-art and idealized materials. STEGs can produce electricity by using sunlight to heat one side of a thermoelectric generator. While concentrated sunlight can be used to achieve extremely high temperatures (and thus improved generator efficiency), the solar absorber also emits a significant amount of black body radiation. This emitted light is the dominant loss mechanism in these generators. In this invention, we propose a solution to this problem that eliminates virtually all of the emitted black body radiation. This enables solar thermoelectric generators to operate at higher efficiency and achieve said efficient with lower levels of optical concentration. The solution is suitable for both single and dual axis solar thermoelectric generators.

Fabrication of Compact Superconducting Lowpass Filters for Ultrasensitive Detectors

NASA Technical Reports Server (NTRS)

Brown, Ari; Chervenak, James; Chuss, David; Mikula, Vilem; Ray, Christopher; Rostem, Karwan; U-Yen, Kongpop; Wassell, Edward; Wollack, Edward

2012-01-01

It is extremely important for current and future far-infrared and sub-millimeter ultrasensitive detectors, which include transition edge sensors (TES) and microwave kinetic inductance detectors, to be adequately filtered from stray electromagnetic radiation in order to achieve their optimal performance. One means of filtering stray radiation is to block leakage associated with electrical connections in the detector environment. Here we discuss a fabrication methodology for realizing non-dissipative planar filters imbedded in the wall of the detector enclosure to limit wave propagation modes up to far-infrared frequencies. Our methodology consists of fabricating a boxed stripline transmission line, in which a superconducting (Nb, Mo, or Al) transmission line is encased in a silicon dioxide dielectric insulator coated with a metallic shell. We report on achieved attenuation and return loss and find that it replicates the simulated data to a high degree.

Well-Defined High Molecular Weight Polystyrene with High Rates and High Livingness Synthesized via Two-Stage RAFT Emulsion Polymerization.

PubMed

Yan, Kun; Gao, Xiang; Luo, Yingwu

2015-07-01

A highly living polymer with over 100 kg mol(-1) molecular weight is very difficult to achieve by controlled radical polymerization since the unavoidable side reactions of irreversible radical termination and radical chain transfer to monomer reaction become significant. It is reported that over 500 kg mol(-1) polystyrene with high livingness and low dispersity could be synthesized by a facile two-stage reversible addition-fragmentation transfer emulsion polymerization. The monomer conversion reaches 90% within 10 h. High livingness of the product is ascribed to the extremely low initiator concentration and the chain transfer constant for monomer unexpectedly much lower than the well-accepted values in the conventional radical polymerization. The two-stage monomer feeding policy much decreases the dispersity of the product. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gender Differences in Mathematical Achievement at the Norwegian Elementary-School Level.

ERIC Educational Resources Information Center

Manger, Terje

1995-01-01

The relationship between gender and mathematical achievement was investigated in 440 female and 480 male Norwegian third graders. Boys had higher test scores, but the effect size was small. Boys performed better in numeracy, mental arithmetic, and measurement problems. Marked gender differences were found at extreme tails of the distribution.…

Modernizing Distribution System Restoration to Achieve Grid Resiliency Against Extreme Weather Events: An Integrated Solution

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

Chen, Chen; Wang, Jianhui; Ton, Dan

Recent severe power outages caused by extreme weather hazards have highlighted the importance and urgency of improving the resilience of the electric power grid. As the distribution grids still remain vulnerable to natural disasters, the power industry has focused on methods of restoring distribution systems after disasters in an effective and quick manner. The current distribution system restoration practice for utilities is mainly based on predetermined priorities and tends to be inefficient and suboptimal, and the lack of situational awareness after the hazard significantly delays the restoration process. As a result, customers may experience an extended blackout, which causes largemore » economic loss. On the other hand, the emerging advanced devices and technologies enabled through grid modernization efforts have the potential to improve the distribution system restoration strategy. However, utilizing these resources to aid the utilities in better distribution system restoration decision-making in response to extreme weather events is a challenging task. Therefore, this paper proposes an integrated solution: a distribution system restoration decision support tool designed by leveraging resources developed for grid modernization. We first review the current distribution restoration practice and discuss why it is inadequate in response to extreme weather events. Then we describe how the grid modernization efforts could benefit distribution system restoration, and we propose an integrated solution in the form of a decision support tool to achieve the goal. The advantages of the solution include improving situational awareness of the system damage status and facilitating survivability for customers. The paper provides a comprehensive review of how the existing methodologies in the literature could be leveraged to achieve the key advantages. The benefits of the developed system restoration decision support tool include the optimal and efficient allocation of repair crews and resources, the expediting of the restoration process, and the reduction of outage durations for customers, in response to severe blackouts due to extreme weather hazards.« less

EUV lithography for 30nm half pitch and beyond: exploring resolution, sensitivity, and LWR tradeoffs

NASA Astrophysics Data System (ADS)

Putna, E. Steve; Younkin, Todd R.; Chandhok, Manish; Frasure, Kent

2009-03-01

The International Technology Roadmap for Semiconductors (ITRS) denotes Extreme Ultraviolet (EUV) lithography as a leading technology option for realizing the 32nm half-pitch node and beyond. Readiness of EUV materials is currently one high risk area according to assessments made at the 2008 EUVL Symposium. The main development issue regarding EUV resist has been how to simultaneously achieve high sensitivity, high resolution, and low line width roughness (LWR). This paper describes the strategy and current status of EUV resist development at Intel Corporation. Data is presented utilizing Intel's Micro-Exposure Tool (MET) examining the feasibility of establishing a resist process that simultaneously exhibits <=30nm half-pitch (HP) L/S resolution at <=10mJ/cm2 with <=4nm LWR.

EUV lithography for 22nm half pitch and beyond: exploring resolution, LWR, and sensitivity tradeoffs

NASA Astrophysics Data System (ADS)

Putna, E. Steve; Younkin, Todd R.; Caudillo, Roman; Chandhok, Manish

2010-04-01

The International Technology Roadmap for Semiconductors (ITRS) denotes Extreme Ultraviolet (EUV) lithography as a leading technology option for realizing the 22nm half pitch node and beyond. Readiness of EUV materials is currently one high risk area according to recent assessments made at the 2009 EUVL Symposium. The main development issue regarding EUV resist has been how to simultaneously achieve high sensitivity, high resolution, and low line width roughness (LWR). This paper describes the strategy and current status of EUV resist development at Intel Corporation. Data collected utilizing Intel's Micro-Exposure Tool (MET) is presented in order to examine the feasibility of establishing a resist process that simultaneously exhibits <=22nm half-pitch (HP) L/S resolution at <= 12.5mJ/cm2 with <= 4nm LWR.

Magnetic field induced strong valley polarization in the three-dimensional topological semimetal LaBi

NASA Astrophysics Data System (ADS)

Kumar, Nitesh; Shekhar, Chandra; Klotz, J.; Wosnitza, J.; Felser, Claudia

2017-10-01

LaBi is a three-dimensional rocksalt-type material with a surprisingly quasi-two-dimensional electronic structure. It exhibits excellent electronic properties such as the existence of nontrivial Dirac cones, extremely large magnetoresistance, and high charge-carrier mobility. The cigar-shaped electron valleys make the charge transport highly anisotropic when the magnetic field is varied from one crystallographic axis to another. We show that the electrons can be polarized effectively in these electron valleys under a rotating magnetic field. We achieved a polarization of 60% at 2 K despite the coexistence of three-dimensional hole pockets. The valley polarization in LaBi is compared to the sister compound LaSb where it is found to be smaller. The performance of LaBi is comparable to the highly efficient bismuth.

Lithium Ion Batteries in Electric Drive Vehicles

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

Pesaran, Ahmad A.

2016-05-16

This research focuses on the technical issues that are critical to the adoption of high-energy-producing lithium Ion batteries. In addition to high energy density / high power density, this publication considers performance requirements that are necessary to assure lithium ion technology as the battery format of choice for electrified vehicles. Presentation of prime topics includes: long calendar life (greater than 10 years); sufficient cycle life; reliable operation under hot and cold temperatures; safe performance under extreme conditions; end-of-life recycling. To achieve aggressive fuel economy standards, carmakers are developing technologies to reduce fuel consumption, including hybridization and electrification. Cost and affordabilitymore » factors will be determined by these relevant technical issues which will provide for the successful implementation of lithium ion batteries for application in future generations of electrified vehicles.« less

Design of compact surface optical coupler based on vertically curved silicon waveguide for high-numerical-aperture single-mode optical fiber

NASA Astrophysics Data System (ADS)

Atsumi, Yuki; Yoshida, Tomoya; Omoda, Emiko; Sakakibara, Youichi

2017-09-01

A surface optical coupler based on a vertically curved Si waveguide was designed for coupling with high-numerical aperture single-mode optical fibers with a mode-field diameter of 5 µm. This coupler has a quite small device size, with a height of approximately 12 µm, achieved by introducing an effective spot-size converter configured with the combination of an extremely short Si exponential-inverse taper and a dome-structured SiO2 lens formed on the coupler top. The designed coupler shows high-efficiency optical coupling, with a loss of 0.8 dB for TE polarized light, as well as broad-band coupling with a 0.5-dB-loss band of 420 nm.

Towards high-resolution laser ionization spectroscopy of the heaviest elements in supersonic gas jet expansion

PubMed Central

Ferrer, R.; Barzakh, A.; Bastin, B.; Beerwerth, R.; Block, M.; Creemers, P.; Grawe, H.; de Groote, R.; Delahaye, P.; Fléchard, X.; Franchoo, S.; Fritzsche, S.; Gaffney, L. P.; Ghys, L.; Gins, W.; Granados, C.; Heinke, R.; Hijazi, L.; Huyse, M.; Kron, T.; Kudryavtsev, Yu.; Laatiaoui, M.; Lecesne, N.; Loiselet, M.; Lutton, F.; Moore, I. D.; Martínez, Y.; Mogilevskiy, E.; Naubereit, P.; Piot, J.; Raeder, S.; Rothe, S.; Savajols, H.; Sels, S.; Sonnenschein, V.; Thomas, J-C; Traykov, E.; Van Beveren, C.; Van den Bergh, P.; Van Duppen, P.; Wendt, K.; Zadvornaya, A.

2017-01-01

Resonant laser ionization and spectroscopy are widely used techniques at radioactive ion beam facilities to produce pure beams of exotic nuclei and measure the shape, size, spin and electromagnetic multipole moments of these nuclei. However, in such measurements it is difficult to combine a high efficiency with a high spectral resolution. Here we demonstrate the on-line application of atomic laser ionization spectroscopy in a supersonic gas jet, a technique suited for high-precision studies of the ground- and isomeric-state properties of nuclei located at the extremes of stability. The technique is characterized in a measurement on actinium isotopes around the N=126 neutron shell closure. A significant improvement in the spectral resolution by more than one order of magnitude is achieved in these experiments without loss in efficiency. PMID:28224987

Preparation of 3D nanoporous copper-supported cuprous oxide for high-performance lithium ion battery anodes.

PubMed

Liu, Dequan; Yang, Zhibo; Wang, Peng; Li, Fei; Wang, Desheng; He, Deyan

2013-03-07

Three-dimensional (3D) nanoporous architectures can provide efficient and rapid pathways for Li-ion and electron transport as well as short solid-state diffusion lengths in lithium ion batteries (LIBs). In this work, 3D nanoporous copper-supported cuprous oxide was successfully fabricated by low-cost selective etching of an electron-beam melted Cu(50)Al(50) alloy and subsequent in situ thermal oxidation. The architecture was used as an anode in lithium ion batteries. In the first cycle, the sample delivered an extremely high lithium storage capacity of about 2.35 mA h cm(-2). A high reversible capacity of 1.45 mA h cm(-2) was achieved after 120 cycles. This work develops a promising approach to building reliable 3D nanostructured electrodes for high-performance lithium ion batteries.

Highly Stereoselective Synthesis of a Compound Collection Based on the Bicyclic Scaffolds of Natural Products.

PubMed

Annamalai, Murali; Hristeva, Stanimira; Bielska, Martyna; Ortega, Raquel; Kumar, Kamal

2017-05-18

Despite the great contribution of natural products in the history of successful drug discovery, there are significant limitations that persuade the pharmaceutical industry to evade natural products in drug discovery research. The extreme scarcity as well as structural complexity of natural products renders their practical synthetic access and further modifications extremely challenging. Although other alternative technologies, particularly combinatorial chemistry, were embraced by the pharmaceutical industry to get quick access to a large number of small molecules with simple frameworks that often lack three-dimensional complexity, hardly any success was achieved in the discovery of lead molecules. To acquire chemotypes beholding structural features of natural products, for instance high sp ³ character, the synthesis of compound collections based on core-scaffolds of natural products presents a promising strategy. Here, we report a natural product inspired synthesis of six different chemotypes and their derivatives for drug discovery research. These bicyclic hetero- and carbocyclic scaffolds are highly novel, rich in sp ³ features and with ideal physicochemical properties to display drug likeness. The functional groups on the scaffolds were exploited further to generate corresponding compound collections. Synthesis of two of these collections exemplified with ca. 350 compounds are each also presented. The whole compound library is being exposed to various biological screenings within the European Lead Factory consortium.

A comprehensive review of the role of zinc in normal prostate function and metabolism; and its implications in prostate cancer☆

PubMed Central

Costello, Leslie C.; Franklin, Renty B.

2016-01-01

The human prostate gland contains extremely high zinc levels; which is due to the specialized zinc-accumulating acinar epithelial of the peripheral zone. These cells evolved for their unique capability to produce and secrete extremely levels of citrate, which is achieved by the high cellular zinc level effects on the cell metabolism. This review highlights the specific functional and metabolic alterations that result from the accumulation of the high zinc levels, especially its effects on mitochondrial citrate metabolism and terminal oxidation. The implications of zinc in the development and progression of prostate cancer are described, which is the most consistent hallmark characteristic of prostate cancer. The requirement for decreased zinc resulting from down regulation of ZIP1 to prevent zinc cytotoxicity in the malignant cells is described as an essential early event in prostate oncogenesis. This provides the basis for the concept that an agent (such as the zinc ionophore, clioquinol) that facilitates zinc uptake and accumulation in ZIP1-deficient prostate tumors cells will markedly inhibit tumor growth. In the current absence of an efficacious chemotherapy for advanced prostate cancer, and for prevention of early development of malignancy; a zinc treatment regimen is a plausible approach that should be pursued. PMID:27132038

Slowing down the speed of light using an electromagnetically-induced-transparency mechanism in a modified reservoir

NASA Astrophysics Data System (ADS)

Liu, Ronggang; Liu, Tong; Wang, Yingying; Li, Yujie; Gai, Bingzheng

2017-11-01

We propose an effective method to achieve extremely slow light by using both the mechanism of electromagnetically induced transparency (EIT) and the localization of a coupled cavity waveguide (CCW). Based on quantum mechanics theory and the dispersion relation of a CCW, we derive a group-velocity formula that reveals both the effects of the EIT and CCW. Results show that ultralow light velocity at the order of several meters per second or even static light, could be obtained feasibly. In comparison with the EIT mechanism in a background of vacuum, this proposed method is more effective and realistic to achieve extremely slow light. And it exhibits potential values in the field of light storage.

Telescience - Concepts and contributions to the Extreme Ultraviolet Explorer mission

NASA Technical Reports Server (NTRS)

Marchant, Will; Dobson, Carl; Chakrabarti, Supriya; Malina, Roger F.

1987-01-01

It is shown how the contradictory goals of low-cost and fast data turnaround characterizing the Extreme Ultraviolet Explorer (EUVE) mission can be achieved via the early use of telescience style transparent tools and simulations. The use of transparent tools reduces the parallel development of capability while ensuring that valuable prelaunch experience is not lost in the operations phase. Efforts made to upgrade the 'EUVE electronics' simulator are described.

Spatio-temporal characteristics of the extreme precipitation by L-moment-based index-flood method in the Yangtze River Delta region, China

NASA Astrophysics Data System (ADS)

Yin, Yixing; Chen, Haishan; Xu, Chong-Yu; Xu, Wucheng; Chen, Changchun; Sun, Shanlei

2016-05-01

The regionalization methods, which "trade space for time" by pooling information from different locations in the frequency analysis, are efficient tools to enhance the reliability of extreme quantile estimates. This paper aims at improving the understanding of the regional frequency of extreme precipitation by using regionalization methods, and providing scientific background and practical assistance in formulating the regional development strategies for water resources management in one of the most developed and flood-prone regions in China, the Yangtze River Delta (YRD) region. To achieve the main goals, L-moment-based index-flood (LMIF) method, one of the most popular regionalization methods, is used in the regional frequency analysis of extreme precipitation with special attention paid to inter-site dependence and its influence on the accuracy of quantile estimates, which has not been considered by most of the studies using LMIF method. Extensive data screening of stationarity, serial dependence, and inter-site dependence was carried out first. The entire YRD region was then categorized into four homogeneous regions through cluster analysis and homogenous analysis. Based on goodness-of-fit statistic and L-moment ratio diagrams, generalized extreme-value (GEV) and generalized normal (GNO) distributions were identified as the best fitted distributions for most of the sub-regions, and estimated quantiles for each region were obtained. Monte Carlo simulation was used to evaluate the accuracy of the quantile estimates taking inter-site dependence into consideration. The results showed that the root-mean-square errors (RMSEs) were bigger and the 90 % error bounds were wider with inter-site dependence than those without inter-site dependence for both the regional growth curve and quantile curve. The spatial patterns of extreme precipitation with a return period of 100 years were finally obtained which indicated that there are two regions with highest precipitation extremes and a large region with low precipitation extremes. However, the regions with low precipitation extremes are the most developed and densely populated regions of the country, and floods will cause great loss of human life and property damage due to the high vulnerability. The study methods and procedure demonstrated in this paper will provide useful reference for frequency analysis of precipitation extremes in large regions, and the findings of the paper will be beneficial in flood control and management in the study area.

Linear-constraint wavefront control for exoplanet coronagraphic imaging systems

NASA Astrophysics Data System (ADS)

Sun, He; Eldorado Riggs, A. J.; Kasdin, N. Jeremy; Vanderbei, Robert J.; Groff, Tyler Dean

2017-01-01

A coronagraph is a leading technology for achieving high-contrast imaging of exoplanets in a space telescope. It uses a system of several masks to modify the diffraction and achieve extremely high contrast in the image plane around target stars. However, coronagraphic imaging systems are very sensitive to optical aberrations, so wavefront correction using deformable mirrors (DMs) is necessary to avoid contrast degradation in the image plane. Electric field conjugation (EFC) and Stroke minimization (SM) are two primary high-contrast wavefront controllers explored in the past decade. EFC minimizes the average contrast in the search areas while regularizing the strength of the control inputs. Stroke minimization calculates the minimum DM commands under the constraint that a target average contrast is achieved. Recently in the High Contrast Imaging Lab at Princeton University (HCIL), a new linear-constraint wavefront controller based on stroke minimization was developed and demonstrated using numerical simulation. Instead of only constraining the average contrast over the entire search area, the new controller constrains the electric field of each single pixel using linear programming, which could led to significant increases in speed of the wavefront correction and also create more uniform dark holes. As a follow-up of this work, another linear-constraint controller modified from EFC is demonstrated theoretically and numerically and the lab verification of the linear-constraint controllers is reported. Based on the simulation and lab results, the pros and cons of linear-constraint controllers are carefully compared with EFC and stroke minimization.

Progress towards extreme attitude testing with Magnetic Suspension and Balance Systems

NASA Technical Reports Server (NTRS)

Britcher, Colin P.; Parker, David H.

1988-01-01

Progress is reported in a research effort aimed towards demonstration of the feasibility of suspension and aerodynamic testing of models at high angles of attack in wind tunnel Magnetic Suspension and Balance Systems. Extensive modifications, described in this paper, have been made to the Southampton University suspension system in order to facilitate this work. They include revision of electromagnet configuration, installation of all-new position sensors and expansion of control system programs. An angle of attack range of 0 to 90 deg is expected for axisymmetric models. To date, suspension up to 80 deg angle of attack has been achieved.

Two phase microstructure for Ag-Ni nanowires

NASA Astrophysics Data System (ADS)

Srivastava, Chandan; Rai, Rajesh Kumar

2013-03-01

In the present study, electrodeposition technique was used to produce Ag-Ni nanowires. Ag-Ni system shows extremely high bulk immiscibility. Nanowire morphology was achieved by employing an anodic alumina membrane having pores of ˜200 nm diameter. Microstructure of as-deposited wire was composed of nano-sized solid solution structured Ag-Ni nanoparticles embedded in a matrix of pure Ag phase. It is proposed that the two phase microstructure resulted from an initial formation of solid solution structured nanoparticles in the alumina template pore followed by nucleation of pure Ag phase over the particles which eventually grew to form the matrix phase.

A fast isogeometric BEM for the three dimensional Laplace- and Helmholtz problems

NASA Astrophysics Data System (ADS)

Dölz, Jürgen; Harbrecht, Helmut; Kurz, Stefan; Schöps, Sebastian; Wolf, Felix

2018-03-01

We present an indirect higher order boundary element method utilising NURBS mappings for exact geometry representation and an interpolation-based fast multipole method for compression and reduction of computational complexity, to counteract the problems arising due to the dense matrices produced by boundary element methods. By solving Laplace and Helmholtz problems via a single layer approach we show, through a series of numerical examples suitable for easy comparison with other numerical schemes, that one can indeed achieve extremely high rates of convergence of the pointwise potential through the utilisation of higher order B-spline-based ansatz functions.

Development and technical implementation of the separation nozzle process for enrichment of uranium-235

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

Becker, E.W.; Bier, W.; Bley, P.

In the separation nozzle process, enrichment is achieved by extremely high centrifugal forces in a curved flow of UF/sub 6/ diluted by a light gas. The first commercial application is in Brasil, where a so-called First Cascade consisting of 24 separation nozzle stages is under construction. In two steps, this installation will be expanded into a 300,000 SWU/a demonstration plant. The development of components for commercial plants is well under way. The paper describes developments and technical implementation of the separation nozzle process. Remarkable progress has been made in the process economy.

Measuring the absolute carrier-envelope phase of many-cycle laser fields

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

Tzallas, P.; Skantzakis, E.; Charalambidis, D.

2010-12-15

The carrier-envelope phase (CEP) of high-peak-power, many-cycle laser fields becomes a crucial parameter when such fields are used, in conjunction with polarization gating techniques, in isolated attosecond (asec) pulse generation. However, its measurement has not been achieved so far. We demonstrate a physical process sensitive to the CEP value of such fields and describe a method for its online shot-to-shot monitoring. This work paves the way for the exploitation of energetic isolated asec pulses in studies of nonlinear extreme ultraviolet (XUV) processes and XUV-pump-XUV-probe experiments with asec resolutions.

Ellipsometric Analysis of Contaminant Layer on Optical Witness Samples from MISSE

NASA Technical Reports Server (NTRS)

Norwood, Joseph K.

2007-01-01

Several optical witness samples included in the Materials for International Space Station Experiment (MISSE) trays have been analyzed with a variable angle spectroscopic ellipsometer or VASE. Witness samples of gold or platinum mirrors are extremely useful as collectors of space-borne contamination, due to the relative inertness of these noble metals in the atomic oxygen-rich environment of LEO. Highly accurate thickness measurements, typically at the sub-nanometer scale, may be achieved with this method, which uses polarized light in a spectral range of 300 to 1300 nanometers at several angles of incidence to the sample surface.

High Step-Up DC—DC Converter for AC Photovoltaic Module with MPPT Control

NASA Astrophysics Data System (ADS)

Sundar, Govindasamy; Karthick, Narashiman; Rama Reddy, Sasi

2014-08-01

This paper presents the high gain step-up BOOST converter which is essential to step up the low output voltage from PV panel to the high voltage according to the requirement of the application. In this paper a high gain BOOST converter with coupled inductor technique is proposed with the MPPT control. Without extreme duty ratios and the numerous turns-ratios of a coupled inductor this converter achieves a high step-up voltage-conversion ratio and the leakage energy of the coupled inductor is efficiently recycled to the load. MPPT control used to extract the maximum power from PV panel by controlling the Duty ratio of the converter. The PV panel, BOOST converter and the MPPT are modeled using Sim Power System blocks in MATLAB/SIMULINK environment. The prototype model of the proposed converter has been implemented with the maximum measured efficiency is up to 95.4% and full-load efficiency is 93.1%.

Effect of Fuel Injection and Mixing Characteristics on Pulse-Combustor Performance at High-Pressure

NASA Technical Reports Server (NTRS)

Yungster, Shaye; Paxson, Daniel E.; Perkins, Hugh D.

2014-01-01

Recent calculations of pulse-combustors operating at high-pressure conditions produced pressure gains significantly lower than those observed experimentally and computationally at atmospheric conditions. The factors limiting the pressure-gain at high-pressure conditions are identified, and the effects of fuel injection and air mixing characteristics on performance are investigated. New pulse-combustor configurations were developed, and the results show that by suitable changes to the combustor geometry, fuel injection scheme and valve dynamics the performance of the pulse-combustor operating at high-pressure conditions can be increased to levels comparable to those observed at atmospheric conditions. In addition, the new configurations can significantly reduce the levels of NOx emissions. One particular configuration resulted in extremely low levels of NO, producing an emission index much less than one, although at a lower pressure-gain. Calculations at representative cruise conditions demonstrated that pulse-combustors can achieve a high level of performance at such conditions.

Freestanding, heat resistant microporous film for use in energy storage devices

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

Pekala, Richard W.; Cherukupalli, Srinivas; Waterhouse, Robert R.

Preferred embodiments of a freestanding, heat resistant microporous polymer film (10) constructed for use in an energy storage device (70, 100) implements one or more of the following approaches to exhibit excellent high temperature mechanical and dimensional stability: incorporation into a porous polyolefin film of sufficiently high loading levels of inorganic or ceramic filler material (16) to maintain porosity (18) and achieve low thermal shrinkage; use of crosslinkable polyethylene to contribute to crosslinking the polymer matrix (14) in a highly inorganic material-filled polyolefin film; and heat treating or annealing of biaxially oriented, highly inorganic material-filled polyolefin film above the meltingmore » point temperature of the polymer matrix to reduce residual stress while maintaining high porosity. The freestanding, heat resistant microporous polymer film embodiments exhibit extremely low resistance, as evidenced by MacMullin numbers of less than 4.5.« less

Fabrication of Highly Stable and Efficient PtCu Alloy Nanoparticles on Highly Porous Carbon for Direct Methanol Fuel Cells.

PubMed

Khan, Inayat Ali; Qian, Yuhong; Badshah, Amin; Zhao, Dan; Nadeem, Muhammad Arif

2016-08-17

Boosting the durability of Pt nanoparticles by controlling the composition and morphology is extremely important for fuel cells commercialization. We deposit the Pt-Cu alloy nanoparticles over high surface area carbon in different metallic molar ratios and optimize the conditions to achieve desired material. The novel bimetallic electro-catalyst {Pt-Cu/PC-950 (15:15%)} offers exceptional electrocatalytic activity when tested for both oxygen reduction reaction and methanol oxidation reactions. A high mass activity of 0.043 mA/μgPt (based on Pt mass) is recorded for ORR. An outstanding longevity of this electro-catalyst is noticed when compared to 20 wt % Pt loaded either on PC-950 or commercial carbon. The high surface area carbon support offers enhanced activity and prevents the nanoparticles from agglomeration, migration, and dissolution as evident by TEM analysis.

High Temperature Near-Field NanoThermoMechanical Rectification

PubMed Central

Elzouka, Mahmoud; Ndao, Sidy

2017-01-01

Limited performance and reliability of electronic devices at extreme temperatures, intensive electromagnetic fields, and radiation found in space exploration missions (i.e., Venus & Jupiter planetary exploration, and heliophysics missions) and earth-based applications requires the development of alternative computing technologies. In the pursuit of alternative technologies, research efforts have looked into developing thermal memory and logic devices that use heat instead of electricity to perform computations. However, most of the proposed technologies operate at room or cryogenic temperatures, due to their dependence on material’s temperature-dependent properties. Here in this research, we show experimentally—for the first time—the use of near-field thermal radiation (NFTR) to achieve thermal rectification at high temperatures, which can be used to build high-temperature thermal diodes for performing logic operations in harsh environments. We achieved rectification through the coupling between NFTR and the size of a micro/nano gap separating two terminals, engineered to be a function of heat flow direction. We fabricated and tested a proof-of-concept NanoThermoMechanical device that has shown a maximum rectification of 10.9% at terminals’ temperatures of 375 and 530 K. Experimentally, we operated the microdevice in temperatures as high as about 600 K, demonstrating this technology’s suitability to operate at high temperatures. PMID:28322324

Diesel Combustion and Emission Using High Boost and High Injection Pressure in a Single Cylinder Engine

NASA Astrophysics Data System (ADS)

Aoyagi, Yuzo; Kunishima, Eiji; Asaumi, Yasuo; Aihara, Yoshiaki; Odaka, Matsuo; Goto, Yuichi

Heavy-duty diesel engines have adopted numerous technologies for clean emissions and low fuel consumption. Some are direct fuel injection combined with high injection pressure and adequate in-cylinder air motion, turbo-intercooler systems, and strong steel pistons. Using these technologies, diesel engines have achieved an extremely low CO2 emission as a prime mover. However, heavy-duty diesel engines with even lower NOx and PM emission levels are anticipated. This study achieved high-boost and lean diesel combustion using a single cylinder engine that provides good engine performance and clean exhaust emission. The experiment was done under conditions of intake air quantity up to five times that of a naturally aspirated (NA) engine and 200MPa injection pressure. The adopted pressure booster is an external supercharger that can control intake air temperature. In this engine, the maximum cylinder pressure was increased and new technologies were adopted, including a monotherm piston for endurance of Pmax =30MPa. Moreover, every engine part is newly designed. As the boost pressure increases, the rate of heat release resembles the injection rate and becomes sharper. The combustion and brake thermal efficiency are improved. This high boost and lean diesel combustion creates little smoke; ISCO and ISTHC without the ISNOx increase. It also yields good thermal efficiency.

High Temperature Near-Field NanoThermoMechanical Rectification

NASA Astrophysics Data System (ADS)

Elzouka, Mahmoud; Ndao, Sidy

2017-03-01

Limited performance and reliability of electronic devices at extreme temperatures, intensive electromagnetic fields, and radiation found in space exploration missions (i.e., Venus & Jupiter planetary exploration, and heliophysics missions) and earth-based applications requires the development of alternative computing technologies. In the pursuit of alternative technologies, research efforts have looked into developing thermal memory and logic devices that use heat instead of electricity to perform computations. However, most of the proposed technologies operate at room or cryogenic temperatures, due to their dependence on material’s temperature-dependent properties. Here in this research, we show experimentally—for the first time—the use of near-field thermal radiation (NFTR) to achieve thermal rectification at high temperatures, which can be used to build high-temperature thermal diodes for performing logic operations in harsh environments. We achieved rectification through the coupling between NFTR and the size of a micro/nano gap separating two terminals, engineered to be a function of heat flow direction. We fabricated and tested a proof-of-concept NanoThermoMechanical device that has shown a maximum rectification of 10.9% at terminals’ temperatures of 375 and 530 K. Experimentally, we operated the microdevice in temperatures as high as about 600 K, demonstrating this technology’s suitability to operate at high temperatures.

Large-scale protein-protein interactions detection by integrating big biosensing data with computational model.

PubMed

You, Zhu-Hong; Li, Shuai; Gao, Xin; Luo, Xin; Ji, Zhen

2014-01-01

Protein-protein interactions are the basis of biological functions, and studying these interactions on a molecular level is of crucial importance for understanding the functionality of a living cell. During the past decade, biosensors have emerged as an important tool for the high-throughput identification of proteins and their interactions. However, the high-throughput experimental methods for identifying PPIs are both time-consuming and expensive. On the other hand, high-throughput PPI data are often associated with high false-positive and high false-negative rates. Targeting at these problems, we propose a method for PPI detection by integrating biosensor-based PPI data with a novel computational model. This method was developed based on the algorithm of extreme learning machine combined with a novel representation of protein sequence descriptor. When performed on the large-scale human protein interaction dataset, the proposed method achieved 84.8% prediction accuracy with 84.08% sensitivity at the specificity of 85.53%. We conducted more extensive experiments to compare the proposed method with the state-of-the-art techniques, support vector machine. The achieved results demonstrate that our approach is very promising for detecting new PPIs, and it can be a helpful supplement for biosensor-based PPI data detection.

The high velocity, high adiabat, ``Bigfoot'' campaign and tests of indirect-drive implosion scaling

NASA Astrophysics Data System (ADS)

Casey, Daniel

2017-10-01

To achieve hotspot ignition, inertial confinement fusion (ICF) implosions must achieve high hotspot internal energy that is inertially confined by a dense shell of DT fuel. To accomplish this, implosions are designed to achieve high peak implosion velocity, good energy coupling between the hotspot and imploding shell, and high areal-density at stagnation. However, experiments have shown that achieving these simultaneously is extremely challenging, partly because of inherent tradeoffs between these three interrelated requirements. The Bigfoot approach is to intentionally trade off high convergence, and therefore areal-density, in favor of high implosion velocity and good coupling between the hotspot and shell. This is done by intentionally colliding the shocks in the DT ice layer. This results in a short laser pulse which improves hohlraum symmetry and predictability while the reduced compression improves hydrodynamic stability. The results of this campaign will be reviewed and include demonstrated low-mode symmetry control at two different hohlraum geometries (5.75 mm and 5.4 mm diameters) and at two different target scales (5.4 mm and 6.0 mm hohlraum diameters) spanning 300-430 TW in laser power and 0.8-1.7 MJ in laser energy. Results of the 10% scaling between these designs for the hohlraum and capsule will be presented. Hydrodynamic instability growth from engineering features like the capsule fill tube are currently thought to be a significant perturbation to the target performance and a major factor in reducing its performance compared to calculations. Evidence supporting this hypothesis as well as plans going forward will be presented. Ongoing experiments are attempting to measure the impact on target performance from increase in target scale, and the preliminary results will also be discussed. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Cold and Hot Extremozymes: Industrial Relevance and Current Trends

PubMed Central

Sarmiento, Felipe; Peralta, Rocío; Blamey, Jenny M.

2015-01-01

The development of enzymes for industrial applications relies heavily on the use of microorganisms. The intrinsic properties of microbial enzymes, e.g., consistency, reproducibility, and high yields along with many others, have pushed their introduction into a wide range of products and industrial processes. Extremophilic microorganisms represent an underutilized and innovative source of novel enzymes. These microorganisms have developed unique mechanisms and molecular means to cope with extreme temperatures, acidic and basic pH, high salinity, high radiation, low water activity, and high metal concentrations among other environmental conditions. Extremophile-derived enzymes, or extremozymes, are able to catalyze chemical reactions under harsh conditions, like those found in industrial processes, which were previously not thought to be conducive for enzymatic activity. Due to their optimal activity and stability under extreme conditions, extremozymes offer new catalytic alternatives for current industrial applications. These extremozymes also represent the cornerstone for the development of environmentally friendly, efficient, and sustainable industrial technologies. Many advances in industrial biocatalysis have been achieved in recent years; however, the potential of biocatalysis through the use of extremozymes is far from being fully realized. In this article, the adaptations and significance of psychrophilic, thermophilic, and hyperthermophilic enzymes, and their applications in selected industrial markets will be reviewed. Also, the current challenges in the development and mass production of extremozymes as well as future prospects and trends for their biotechnological application will be discussed. PMID:26539430

Fabrication of high aspect ratio tungsten nanostructures on ultrathin c-Si membranes for extreme UV applications

NASA Astrophysics Data System (ADS)

Delachat, F.; Le Drogoff, B.; Constancias, C.; Delprat, S.; Gautier, E.; Chaker, M.; Margot, J.

2016-01-01

In this work, we demonstrate a full process for fabricating high aspect ratio diffraction optics for extreme ultraviolet lithography. The transmissive optics consists in nanometer scale tungsten patterns standing on flat, ultrathin (100 nm) and highly transparent (>85% at 13.5 nm) silicon membranes (diameter of 1 mm). These tungsten patterns were achieved using an innovative pseudo-Bosch etching process based on an inductively coupled plasma ignited in a mixture of SF6 and C4F8. Circular ultra-thin Si membranes were fabricated through a state-of-the-art method using direct-bonding with thermal difference. The silicon membranes were sputter-coated with a few hundred nanometers (100-300 nm) of stress-controlled tungsten and a very thin layer of chromium. Nanoscale features were written in a thin resist layer by electron beam lithography and transferred onto tungsten by plasma etching of both the chromium hard mask and the tungsten layer. This etching process results in highly anisotropic tungsten features at room temperature. The homogeneity and the aspect ratio of the advanced pattern transfer on the membranes were characterized with scanning electron microscopy after focus ion beam milling. An aspect ratio of about 6 for 35 nm size pattern is successfully obtained on a 1 mm diameter 100 nm thick Si membrane. The whole fabrication process is fully compatible with standard industrial semiconductor technology.

Conditional probability of rainfall extremes across multiple durations

NASA Astrophysics Data System (ADS)

Le, Phuong Dong; Leonard, Michael; Westra, Seth

2017-04-01

The conditional probability that extreme rainfall will occur at one location given that it is occurring at another location is critical in engineering design and management circumstances including planning of evacuation routes and the sitting of emergency infrastructure. A challenge with this conditional simulation is that in many situations the interest is not so much the conditional distributions of rainfall of the same duration at two locations, but rather the conditional distribution of flooding in two neighbouring catchments, which may be influenced by rainfall of different critical durations. To deal with this challenge, a model that can consider both spatial and duration dependence of extremes is required. The aim of this research is to develop a model that can take account both spatial dependence and duration dependence into the dependence structure of extreme rainfalls. To achieve this aim, this study is a first attempt at combining extreme rainfall for multiple durations within a spatial extreme model framework based on max-stable process theory. Max-stable processes provide a general framework for modelling multivariate extremes with spatial dependence for just a single duration extreme rainfall. To achieve dependence across multiple timescales, this study proposes a new approach that includes addition elements representing duration dependence of extremes to the covariance matrix of max-stable model. To improve the efficiency of calculation, a re-parameterization proposed by Koutsoyiannis et al. (1998) is used to reduce the number of parameters necessary to be estimated. This re-parameterization enables the GEV parameters to be represented as a function of timescale. A stepwise framework has been adopted to achieve the overall aims of this research. Firstly, the re-parameterization is used to define a new set of common parameters for marginal distribution across multiple durations. Secondly, spatial interpolation of the new parameter set is used to estimate marginal parameters across the full spatial domain. Finally, spatial interpolation result is used as initial condition to estimate dependence parameters via a likelihood function of max-stable model for multiple durations. The Hawkesbury-Nepean catchment near Sydney in Australia was selected as case study for this research. This catchment has 25 sub-daily rain gauges with the minimum record length of 24 years over a region of 300 km × 300 km area. The re-parameterization was applied for each station for durations from 1 hour to 24 hours and then is evaluated by comparing with the at-site fitted GEV. The evaluation showed that the average R2 for all station is around 0.80 with the range from 0.26 to 1.0. The output of re-parameterization then was used to construct the spatial surface based on covariates including longitude, latitude, and elevation. The dependence model showed good agreements between empirical extremal coefficient and theoretical extremal coefficient for multiple durations. For the overall model, a leave-one-out cross-validation for all stations showed it works well for 20 out of 25 stations. The potential application of this model framework was illustrated through a conditional map of return period and return level across multiple durations, both of which are important for engineering design and management.

University Students and Sustainability Skills in Occupational Health and Safety Master Degree

ERIC Educational Resources Information Center

Míguez-Álvarez, Carla; Arce, Maria Elena; Souto-Gestal, Antonio

2016-01-01

Education is one of the key instruments to achieving global sustainability. In fact, sustainable development has to be integrated into higher education curricula. One of the difficulties of this challenge is to know if students are able to achieve the basic skills, something that is extremely important in emergency management. Thus, assessment of…

Extreme learning machine based optimal embedding location finder for image steganography

PubMed Central

Aljeroudi, Yazan

2017-01-01

In image steganography, determining the optimum location for embedding the secret message precisely with minimum distortion of the host medium remains a challenging issue. Yet, an effective approach for the selection of the best embedding location with least deformation is far from being achieved. To attain this goal, we propose a novel approach for image steganography with high-performance, where extreme learning machine (ELM) algorithm is modified to create a supervised mathematical model. This ELM is first trained on a part of an image or any host medium before being tested in the regression mode. This allowed us to choose the optimal location for embedding the message with best values of the predicted evaluation metrics. Contrast, homogeneity, and other texture features are used for training on a new metric. Furthermore, the developed ELM is exploited for counter over-fitting while training. The performance of the proposed steganography approach is evaluated by computing the correlation, structural similarity (SSIM) index, fusion matrices, and mean square error (MSE). The modified ELM is found to outperform the existing approaches in terms of imperceptibility. Excellent features of the experimental results demonstrate that the proposed steganographic approach is greatly proficient for preserving the visual information of an image. An improvement in the imperceptibility as much as 28% is achieved compared to the existing state of the art methods. PMID:28196080

Radar HRRP Target Recognition Based on Stacked Autoencoder and Extreme Learning Machine

PubMed Central

Liu, Yongxiang; Huo, Kai; Zhang, Zhongshuai

2018-01-01

A novel radar high-resolution range profile (HRRP) target recognition method based on a stacked autoencoder (SAE) and extreme learning machine (ELM) is presented in this paper. As a key component of deep structure, the SAE does not only learn features by making use of data, it also obtains feature expressions at different levels of data. However, with the deep structure, it is hard to achieve good generalization performance with a fast learning speed. ELM, as a new learning algorithm for single hidden layer feedforward neural networks (SLFNs), has attracted great interest from various fields for its fast learning speed and good generalization performance. However, ELM needs more hidden nodes than conventional tuning-based learning algorithms due to the random set of input weights and hidden biases. In addition, the existing ELM methods cannot utilize the class information of targets well. To solve this problem, a regularized ELM method based on the class information of the target is proposed. In this paper, SAE and the regularized ELM are combined to make full use of their advantages and make up for each of their shortcomings. The effectiveness of the proposed method is demonstrated by experiments with measured radar HRRP data. The experimental results show that the proposed method can achieve good performance in the two aspects of real-time and accuracy, especially when only a few training samples are available. PMID:29320453

Radar HRRP Target Recognition Based on Stacked Autoencoder and Extreme Learning Machine.

PubMed

Zhao, Feixiang; Liu, Yongxiang; Huo, Kai; Zhang, Shuanghui; Zhang, Zhongshuai

2018-01-10

A novel radar high-resolution range profile (HRRP) target recognition method based on a stacked autoencoder (SAE) and extreme learning machine (ELM) is presented in this paper. As a key component of deep structure, the SAE does not only learn features by making use of data, it also obtains feature expressions at different levels of data. However, with the deep structure, it is hard to achieve good generalization performance with a fast learning speed. ELM, as a new learning algorithm for single hidden layer feedforward neural networks (SLFNs), has attracted great interest from various fields for its fast learning speed and good generalization performance. However, ELM needs more hidden nodes than conventional tuning-based learning algorithms due to the random set of input weights and hidden biases. In addition, the existing ELM methods cannot utilize the class information of targets well. To solve this problem, a regularized ELM method based on the class information of the target is proposed. In this paper, SAE and the regularized ELM are combined to make full use of their advantages and make up for each of their shortcomings. The effectiveness of the proposed method is demonstrated by experiments with measured radar HRRP data. The experimental results show that the proposed method can achieve good performance in the two aspects of real-time and accuracy, especially when only a few training samples are available.

A Partnership between English Language Learners and a Team of Rocket Scientists: EPO for the NASA SDO Extreme-Ultraviolet Variability Experiment (EVE)

NASA Astrophysics Data System (ADS)

Buhr, S. M.; Eparvier, F.; McCaffrey, M.; Murillo, M.

2007-12-01

Recent immigrant high school students were successfully engaged in learning about Sun-Earth connections through a partnership with the NASA SDO Extreme-Ultraviolet Variability Experiment (EVE) project. The students were enrolled in a pilot course as part of the Math, Engineering and Science Achievement MESA) program. For many of the students, this was the only science option available to them due to language limitations. The English Language Learner (ELL) students doubled their achievement on a pre- and post-assessment on the content of the course. Students learned scientific content and vocabulary in English with support in Spanish, attended field trips, hosted scientist speakers, built and deployed space weather monitors as part of the Stanford SOLAR project, and gave final presentations in English, showcasing their new computer skills. Teachers who taught the students in other courses noted gains in the students' willingness to use English in class and noted gains in math skills. The MESA-EVE course won recognition as a Colorado MESA Program of Excellence and is being offered again in 2007-08. The course has been broken into modules for use in shorter after-school environments, or for use by EVE scientists who are outside of the Boulder area. Other EVE EPO includes professional development for teachers and content workshops for journalists.

Tensile strength and failure mechanisms of tantalum at extreme strain rates

NASA Astrophysics Data System (ADS)

Hahn, Eric; Fensin, Saryu; Germann, Timothy; Meyers, Marc

Non-equilibrium molecular dynamics simulations are used to probe the tensile response of monocrystalline, bicrystalline, and nanocrystalline tantalum over six orders of magnitude of strain rate. Our analysis of the strain rate dependence of strength is extended to over nine orders of magnitude by bridging the present simulations to recent laser-driven shock experiments. Tensile strength shows a power-law dependence with strain rate over this wide range, with different relationships depending on the initial microstructure and active deformation mechanism. At high strain rates, multiple spall events occur independently and continue to occur until communication occurs by means of relaxation waves. Temperature plays a significant role in the reduction of spall strength as the initial shock required to achieve such large strain rates also contributes to temperature rise, through pressure-volume work as well as visco-plastic heating, which leads to softening and sometimes melting upon release. At ultra-high strain rates, those approaching or exceeding the atomic vibrational frequency, spall strength saturates at the ultimate cohesive strength of the material. UC Research Laboratories Grant (09-LR-06-118456-MEYM); Department of Energy NNSA/SSAP (DE-NA0002080); DOE ASCR Exascale Co-design Center for Materials in Extreme Environments.

Extreme Adaptive Optics for the Thirty Meter Telescope

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

Macintosh, B; al., e

2006-05-02

Direct detection of extrasolar Jovian planets is a major scientific motivation for the construction of future extremely large telescopes such as the Thirty Meter Telescope (TMT). Such detection will require dedicated high-contrast AO systems. Since the properties of Jovian planets and their parent stars vary enormously between different populations, the instrument must be designed to meet specific scientific needs rather than a simple metric such as maximum Strehl ratio. We present a design for such an instrument, the Planet Formation Imager (PFI) for TMT. It has four key science missions. The first is the study of newly-formed planets on 5-10more » AU scales in regions such as Taurus and Ophiucus--this requires very small inner working distances that are only possible with a 30m or larger telescope. The second is a robust census of extrasolar giant planets orbiting mature nearby stars. The third is detailed spectral characterization of the brightest extrasolar planets. The final targets are circumstellar dust disks, including Zodiacal light analogs in the inner parts of other solar systems. To achieve these, PFI combines advanced wavefront sensors, high-order MEMS deformable mirrors, a coronagraph optimized for a finely-segmented primary mirror, and an integral field spectrograph.« less

Dual-energy imaging of bone marrow edema on a dedicated multi-source cone-beam CT system for the extremities

NASA Astrophysics Data System (ADS)

Zbijewski, W.; Sisniega, A.; Stayman, J. W.; Thawait, G.; Packard, N.; Yorkston, J.; Demehri, S.; Fritz, J.; Siewerdsen, J. H.

2015-03-01

Purpose: Arthritis and bone trauma are often accompanied by bone marrow edema (BME). BME is challenging to detect in CT due to the overlaying trabecular structure but can be visualized using dual-energy (DE) techniques to discriminate water and fat. We investigate the feasibility of DE imaging of BME on a dedicated flat-panel detector (FPD) extremities cone-beam CT (CBCT) with a unique x-ray tube with three longitudinally mounted sources. Methods: Simulations involved a digital BME knee phantom imaged with a 60 kVp low-energy beam (LE) and 105 kVp high-energy beam (HE) (+0.25 mm Ag filter). Experiments were also performed on a test-bench with a Varian 4030CB FPD using the same beam energies as the simulation study. A three-source configuration was implemented with x-ray sources distributed along the longitudinal axis and DE CBCT acquisition in which the superior and inferior sources operate at HE (and collect half of the projection angles each) and the central source operates at LE. Three-source DE CBCT was compared to a double-scan, single-source orbit. Experiments were performed with a wrist phantom containing a 50 mg/ml densitometry insert submerged in alcohol (simulating fat) with drilled trabeculae down to ~1 mm to emulate the trabecular matrix. Reconstruction-based three-material decomposition of fat, soft tissue, and bone was performed. Results: For a low-dose scan (36 mAs in the HE and LE data), DE CBCT achieved combined accuracy of ~0.80 for a pattern of BME spherical lesions ranging 2.5 - 10 mm diameter in the knee phantom. The accuracy increased to ~0.90 for a 360 mAs scan. Excellent DE discrimination of the base materials was achieved in the experiments. Approximately 80% of the alcohol (fat) voxels in the trabecular phantom was properly identified both for single and 3-source acquisitions, indicating the ability to detect edemous tissue (water-equivalent plastic in the body of the densitometry insert) from the fat inside the trabecular matrix (emulating normal trabecular bone with significant fraction of yellow marrow). Conclusion: Detection of BME and quantification of water and fat content were achieved in extremities DE CBCT with a longitudinal configuration of sources providing DE imaging in a single gantry rotation. The findings support the development of DE imaging capability for CBCT of the extremities in areas conventionally in the domain of MRI.

Dual-Energy Imaging of Bone Marrow Edema on a Dedicated Multi-Source Cone-Beam CT System for the Extremities

PubMed Central

Zbijewski, W.; Sisniega, A.; Stayman, J. W.; Thawait, G.; Packard, N.; Yorkston, J.; Demehri, S.; Fritz, J.; Siewerdsen, J. H.

2015-01-01

Purpose Arthritis and bone trauma are often accompanied by bone marrow edema (BME). BME is challenging to detect in CT due to the overlaying trabecular structure but can be visualized using dual-energy (DE) techniques to discriminate water and fat. We investigate the feasibility of DE imaging of BME on a dedicated flat-panel detector (FPD) extremities cone-beam CT (CBCT) with a unique x-ray tube with three longitudinally mounted sources. Methods Simulations involved a digital BME knee phantom imaged with a 60 kVp low-energy beam (LE) and 105 kVp high-energy beam (HE) (+0.25 mm Ag filter). Experiments were also performed on a test-bench with a Varian 4030CB FPD using the same beam energies as the simulation study. A three-source configuration was implemented with x-ray sources distributed along the longitudinal axis and DE CBCT acquisition in which the superior and inferior sources operate at HE (and collect half of the projection angles each) and the central source operates at LE. Three-source DE CBCT was compared to a double-scan, single-source orbit. Experiments were performed with a wrist phantom containing a 50 mg/ml densitometry insert submerged in alcohol (simulating fat) with drilled trabeculae down to ~1 mm to emulate the trabecular matrix. Reconstruction-based three-material decomposition of fat, soft tissue, and bone was performed. Results For a low-dose scan (36 mAs in the HE and LE data), DE CBCT achieved combined accuracy of ~0.80 for a pattern of BME spherical lesions ranging 2.5 – 10 mm diameter in the knee phantom. The accuracy increased to ~0.90 for a 360 mAs scan. Excellent DE discrimination of the base materials was achieved in the experiments. Approximately 80% of the alcohol (fat) voxels in the trabecular phantom was properly identified both for single and 3-source acquisitions, indicating the ability to detect edemous tissue (water-equivalent plastic in the body of the densitometry insert) from the fat inside the trabecular matrix (emulating normal trabecular bone with significant fraction of yellow marrow). Conclusion Detection of BME and quantification of water and fat content were achieved in extremities DE CBCT with a longitudinal configuration of sources providing DE imaging in a single gantry rotation. The findings support the development of DE imaging capability for CBCT of the extremities in areas conventionally in the domain of MRI. PMID:26045631

Dual-Energy Imaging of Bone Marrow Edema on a Dedicated Multi-Source Cone-Beam CT System for the Extremities.

PubMed

Zbijewski, W; Sisniega, A; Stayman, J W; Thawait, G; Packard, N; Yorkston, J; Demehri, S; Fritz, J; Siewerdsen, J H

2015-02-21

Arthritis and bone trauma are often accompanied by bone marrow edema (BME). BME is challenging to detect in CT due to the overlaying trabecular structure but can be visualized using dual-energy (DE) techniques to discriminate water and fat. We investigate the feasibility of DE imaging of BME on a dedicated flat-panel detector (FPD) extremities cone-beam CT (CBCT) with a unique x-ray tube with three longitudinally mounted sources. Simulations involved a digital BME knee phantom imaged with a 60 kVp low-energy beam (LE) and 105 kVp high-energy beam (HE) (+0.25 mm Ag filter). Experiments were also performed on a test-bench with a Varian 4030CB FPD using the same beam energies as the simulation study. A three-source configuration was implemented with x-ray sources distributed along the longitudinal axis and DE CBCT acquisition in which the superior and inferior sources operate at HE (and collect half of the projection angles each) and the central source operates at LE. Three-source DE CBCT was compared to a double-scan, single-source orbit. Experiments were performed with a wrist phantom containing a 50 mg/ml densitometry insert submerged in alcohol (simulating fat) with drilled trabeculae down to ~1 mm to emulate the trabecular matrix. Reconstruction-based three-material decomposition of fat, soft tissue, and bone was performed. For a low-dose scan (36 mAs in the HE and LE data), DE CBCT achieved combined accuracy of ~0.80 for a pattern of BME spherical lesions ranging 2.5 - 10 mm diameter in the knee phantom. The accuracy increased to ~0.90 for a 360 mAs scan. Excellent DE discrimination of the base materials was achieved in the experiments. Approximately 80% of the alcohol (fat) voxels in the trabecular phantom was properly identified both for single and 3-source acquisitions, indicating the ability to detect edemous tissue (water-equivalent plastic in the body of the densitometry insert) from the fat inside the trabecular matrix (emulating normal trabecular bone with significant fraction of yellow marrow). Detection of BME and quantification of water and fat content were achieved in extremities DE CBCT with a longitudinal configuration of sources providing DE imaging in a single gantry rotation. The findings support the development of DE imaging capability for CBCT of the extremities in areas conventionally in the domain of MRI.

Durham extremely large telescope adaptive optics simulation platform.

PubMed

Basden, Alastair; Butterley, Timothy; Myers, Richard; Wilson, Richard

2007-03-01

Adaptive optics systems are essential on all large telescopes for which image quality is important. These are complex systems with many design parameters requiring optimization before good performance can be achieved. The simulation of adaptive optics systems is therefore necessary to categorize the expected performance. We describe an adaptive optics simulation platform, developed at Durham University, which can be used to simulate adaptive optics systems on the largest proposed future extremely large telescopes as well as on current systems. This platform is modular, object oriented, and has the benefit of hardware application acceleration that can be used to improve the simulation performance, essential for ensuring that the run time of a given simulation is acceptable. The simulation platform described here can be highly parallelized using parallelization techniques suited for adaptive optics simulation, while still offering the user complete control while the simulation is running. The results from the simulation of a ground layer adaptive optics system are provided as an example to demonstrate the flexibility of this simulation platform.

Fiber Bragg Grating Dilatometry in Extreme Magnetic Field and Cryogenic Conditions

PubMed Central

Corvalán Moya, Carolina; Weickert, Franziska; Zapf, Vivien; Balakirev, Fedor F.; Wartenbe, Mark; Rosa, Priscila F. S.; Betts, Jonathan B.; Crooker, Scott A.; Daou, Ramzy

2017-01-01

In this work, we review single mode SiO2 fiber Bragg grating techniques for dilatometry studies of small single-crystalline samples in the extreme environments of very high, continuous, and pulsed magnetic fields of up to 150 T and at cryogenic temperatures down to <1 K. Distinct millimeter-long materials are measured as part of the technique development, including metallic, insulating, and radioactive compounds. Experimental strategies are discussed for the observation and analysis of the related thermal expansion and magnetostriction of materials, which can achieve a strain sensitivity (ΔL/L) as low as a few parts in one hundred million (≈10−8). The impact of experimental artifacts, such as those originating in the temperature dependence of the fiber’s index of diffraction, light polarization rotation in magnetic fields, and reduced strain transfer from millimeter-long specimens, is analyzed quantitatively using analytic models available in the literature. We compare the experimental results with model predictions in the small-sample limit, and discuss the uncovered discrepancies. PMID:29117137

Fiber Bragg Grating Dilatometry in Extreme Magnetic Field and Cryogenic Conditions.

PubMed

Jaime, Marcelo; Corvalán Moya, Carolina; Weickert, Franziska; Zapf, Vivien; Balakirev, Fedor F; Wartenbe, Mark; Rosa, Priscila F S; Betts, Jonathan B; Rodriguez, George; Crooker, Scott A; Daou, Ramzy

2017-11-08

In this work, we review single mode SiO₂ fiber Bragg grating techniques for dilatometry studies of small single-crystalline samples in the extreme environments of very high, continuous, and pulsed magnetic fields of up to 150 T and at cryogenic temperatures down to <1 K. Distinct millimeter-long materials are measured as part of the technique development, including metallic, insulating, and radioactive compounds. Experimental strategies are discussed for the observation and analysis of the related thermal expansion and magnetostriction of materials, which can achieve a strain sensitivity ( ΔL/L ) as low as a few parts in one hundred million (≈10 -8 ). The impact of experimental artifacts, such as those originating in the temperature dependence of the fiber's index of diffraction, light polarization rotation in magnetic fields, and reduced strain transfer from millimeter-long specimens, is analyzed quantitatively using analytic models available in the literature. We compare the experimental results with model predictions in the small-sample limit, and discuss the uncovered discrepancies.

Hydrogen and its compounds under extreme pressure

NASA Astrophysics Data System (ADS)

Utyuzh, A. N.; Mikheyenkov, A. V.

2017-12-01

In the last two or three years, significant advances in the study of hydrogen and its compounds under extreme conditions (ultrahigh pressures over a wide temperature range) have notably changed the hydrogen phase diagram, provided a break-through in understanding hydrides’ behavior under pressure (as exemplified by the discovery of high-temperature superconductivity in hydrogen sulfide), and, finally, enabled achieving cold metallization of hydrogen. The situation prior to the 2010s is reviewed in brief and more recent work is examined in detail. While the primary focus is on experimental research, mention is also made of the theoretical and numerical work it stimulates. This review presents an extension of the talk by the authors for the scientific session of the Physical Sciences Division of the Russian Academy of Sciences, “Old and new ideas in phase transition physics,” which was held on December 21, 2016 (see Phys. Usp. 60 948-957 (2017); Usp. Fiz. Nauk 187 1021 (2017)). (Editor’s note.)

Fiber Bragg Grating Dilatometry in Extreme Magnetic Field and Cryogenic Conditions

DOE PAGES

Jaime, Marcelo; Corvalán Moya, Carolina; Weickert, Franziska; ...

2017-11-08

In this work, we review single mode SiO 2 fiber Bragg grating techniques for dilatometry studies of small single-crystalline samples in the extreme environments of very high, continuous, and pulsed magnetic fields of up to 150 T and at cryogenic temperatures down to <1 K. Distinct millimeter-long materials are measured as part of the technique development, including metallic, insulating, and radioactive compounds. Experimental strategies are discussed for the observation and analysis of the related thermal expansion and magnetostriction of materials, which can achieve a strain sensitivity (ΔL/L) as low as a few parts in one hundred million (≈10 -8). Themore » impact of experimental artifacts, such as those originating in the temperature dependence of the fiber’s index of diffraction, light polarization rotation in magnetic fields, and reduced strain transfer from millimeter-long specimens, is analyzed quantitatively using analytic models available in the literature. We compare the experimental results with model predictions in the small-sample limit, and discuss the uncovered discrepancies.« less

Heat-shield for Extreme Entry Environment Technology (HEEET) Development Status

NASA Technical Reports Server (NTRS)

Venkatapathy, Ethiraj; Ellerby, Don; Gage, Peter

2016-01-01

The Heat shield for Extreme Entry Environment Technology (HEEET) Project is a NASA STMD and SMD co-funded effort. The goal is to develop and mission infuse a new ablative Thermal Protection System that can withstand extreme entry. It is targeted to support NASA's high priority missions, as defined in the latest decadal survey, to destinations such as Venus and Saturn in-situ robotic science missions. Entry into these planetary atmospheres results in extreme heating. The entry peak heat-flux and associated pressure are estimated to be between one and two orders of magnitude higher than those experienced by Mars Science Laboratory or Lunar return missions. In the recent New Frontiers community announcement NASA has indicated that it is considering providing an increase to the PI managed mission cost (PIMMC) for investigations utilizing the Heat Shield for Extreme Entry Environment Technology (HEEET) and in addition, NASA is considering limiting the risk assessment to only their accommodation on the spacecraft and the mission environment. The HEEET ablative TPS utilizes 3D weaving technology to manufacture a dual layer material architecture. The 3-D weaving allows for flat panels to be woven. The dual layer consists of a top layer designed to withstand the extreme external environment while the inner or insulating layer by design, is designed to achieve low thermal conductivity, and it keeps the heat from conducting towards the structure underneath. Both arc jet testing combined with material properties have been used to develop thermal response models that allows for comparison of performance with heritage carbon phenolic. A 50% mass efficiency is achieved by the dual layer construct compared to carbon phenolic for a broad range of missions both to Saturn and Venus. The 3-D woven flat preforms are molded to achieve the shape as they are compliant and then resin infusion with curing forms a rigid panels. These panels are then bonded on to the aeroshell structure. Gaps exist between the panels and these gaps have to be filled with seams. The seam material then has to be bonded on to adjacent panels and also to the structure. The heat-shield assembly is shown in Figure 1. One of the significant challenges we have overcome recently is the design, development and testing of the seam. HEEET material development and the seam concept development have utilized some of the unique test capabilities available in the US. The various test facilities utilized in thermal testing along with the entry environment for Saturn and Venus missions are shown in Figure 2. The HEEET project is currently in it's 3rd year of a four-year development. Figure 3 illustrates the key accomplishments to-date and the challenges yet to be overcome before the technology is ready for mission infusion. This proposed presentation will cover both progress that has been made in the HEEET project and also the challenges to be overcome that is highlighted in Figure 3. Objective of the HEEET project is to mature the system in time to support the next New Frontiers opportunity and we believe we are well along the way to mission infuse HEEET.

Heatshield for Extreme Entry Environment Technology (HEEET) Development Status

NASA Technical Reports Server (NTRS)

Ellerby, Don; Gage, Peter; Kazemba, Cole; Mahzari, Milad; Nishioka, Owen; Peterson, Keith; Stackpoole, Mairead; Venkatapathy, Ethiraj; Young, Zion; Poteet, Carl;

MDCT in the evaluation of skeletal trauma: principles, protocols, and clinical applications.

PubMed

Geijer, Mats; El-Khoury, Georges Y

2006-10-01

Multidetector computed tomography (MDCT) scanners have made volume imaging possible and are used extensively to study polytrauma patients, especially in the evaluation of the spine and peripheral skeleton. An MDCT scanner coupled with a modern workstation has become an essential diagnostic tool for any emergency department. Familiarity with the basic physical principles of MDCT such as projection data, section collimation, and beam collimation is important to achieve high-quality imaging while keeping unnecessary radiation to a minimum. After a polytrauma MDCT examination, images can be reconstructed to obtain different slice thickness, slice interval, fields of view, or reconstruction kernels. No additional scanning is needed for imaging the thoracolumbar spine or bony pelvis. High-quality multiplanar reformation (MPR) and three-dimensional (3-D) images can be created at the workstation using the volumetric data. However, MDCT is a high-dose examination, and care should be taken to use as low a dose as possible. In the musculoskeletal system, MDCT has long been used for evaluation of spinal and pelvic trauma; however, the frequency of its use in extremity trauma has been low. In the extremities, radiography seems to underestimate the extent and severity of injury, especially in complex areas such as the shoulder, elbow, wrist, knee, and ankle. MDCT in the extremities is helpful in fracture detection, evaluation, characterization, and treatment planning. The MPR images give excellent structural detail, and the 3-D images help in understanding the spatial relations, which is important for fracture classification and for preoperative planning. MDCT is also helpful in the follow-up of postoperative results, even in the presence of hardware. Tendon injuries can also be evaluated with MDCT.

Acoustic perfect absorber based on metasurface with deep sub-wavelength thickness (Conference Presentation)

NASA Astrophysics Data System (ADS)

Assouar, Badreddine; Li, Yong

2016-04-01

The concept of the coiling up space, based on which artificial structures could exhibit extreme acoustic properties, such as high refractive index, double negativity, near-zero index, etc., have been investigated intensively recently due to the fascinating underlying physics and diverse potential applications [1-3]. One of the most important functionality is the ability to shrink bulky structures into deep sub-wavelength scale. It is therefore intuitive to prospect that the concept of coiling up space, if could be extended into the perforated system, will benefit to significantly reduce the total thickness while keeping total absorption. Conventional acoustic absorbers require a structure with a thickness comparable to the working wavelength, resulting major obstacles in real applications in low frequency range. We present a metasurface-based perfect absorber capable of achieving the total absorption of acoustic wave in extremely low frequency region. The metasurface possessing a deep sub-wavelength thickness down to a feature size of ~ lambda/223 is composed of a perforated plate and a coiled coplanar air chamber. Simulations based on fully coupled acoustic with thermodynamic equations and theoretical impedance analysis are utilized to reveal the underlying physics and the acoustic performances, showing an excellent agreement. Our realization should have high impact on amount of applications due to the extremely thin thickness, easy fabrication and high efficiency of the proposed structure. References 1. Z. Liang and J. Li, Phys. Rev. Lett. 108, 114301 (2012). 2. Y. Li, B. Liang, X. Tao, X. F. Zhu, X. Y. Zou, and J. C. Cheng, Appl. Phys. Lett. 101, 233508 (2012). 3. Y. Xie, W. Wang, H. Chen, A. Konneker, B. I. Popa, and S. A. Cummer, Nat. Commun. 5, 5553 (2014).

Ceramic Strain Gages for Use at Temperatures up to 1500 Celsius

NASA Technical Reports Server (NTRS)

Gregory, Otto; Fralick, Gustave (Technical Monitor)

2003-01-01

Indium-tin-oxide (ITO) thin film strain gages were successfully demonstrated at temperatures beyond 1500 C. High temperature static strain tests revealed that the piezoresistive response and electrical stability of the ceramic sensors depended on the thickness of the ITO films comprising the active strain elements. When 2.5 microns-thick ITO films were employed as the active strain elements, the piezoresistive response became unstable at temperatures above 1225 C. In contrast to this, ceramic sensors prepared with 5 microns-thick ITO were stable beyond 1430 C and sensors prepared with 8 microns-thick ITO survived more than 20 hr of operation at 1481 C. Very thick (10 microns) ITo strain gages were extremely stable and responsive at 1528 C. ESCA depth profiles confirmed that an interfacial reaction between the ITO strain gage and alumina substrate was responsible for the high temperature electrical stability observed. Similar improvements in high temperature stability were achieved by doping the active ITO strain elements with aluminum. Several Sic-Sic CMC constant strain beams were instrumented with ITO strain gages and delivered to NASA for testing. Due to the extreme surface roughness of the CMC substrates, new lithography techniques and surface preparation methods were developed. These techniques relied heavily on a combination of Sic and A12O3 cement layers to provide the necessary surface finish for efficient pattern transfer. Micro-contact printing using soft lithography and PDMS stamps was also used to successfully transfer the thin film strain gage patterns to the resist coated CMC substrates. This latter approach has considerable potential for transferring the thin film strain gage patterns to the extremely rough surfaces associated with the CMC's.

[The effects of electromagnetic radiation of extremely high frequency and low intensity on the growth rate of bacteria Escherichia coli and the role of medium pH].

PubMed

Tadevosian, A; Kalantarian, V; Trchunian, A

2007-01-01

It has been shown that coherent electromagnetic irradiation (EMI) of extremely high frequency (45-53 GHz) or millimeter waves (wavelength 5.6-6.7 mm) of low intensity (flux capacity 0.06 mW/cm2) of Escherichia coli K12, grown under anaerobic conditions during the fermentation of sugar (glucose) for 30 min or 1 h, caused a decrease in their growth rate, the maximum inhibitory effect being achieved at a frequency of 51.8 or 53 GHz. This effect depended on medium pH when the maximal action was determined at pH 7.5. In addition, separate 30-min of 1-h irradiation (frequency 51.8 or 53 GHz) of doubly distilled water or some inorganic ions contained in Tris-phosphate buffer where the cells were transferred induced oppositely directed changes in further growth of these bacteria under anaerobic conditions; irradiation of water caused a decrease in the growth rate of bacteria. A significant change in pH of water (0.5-1.5 unit) was induced by a 30-irradiation at a frequency of 49, 50.3, 51.8, or 53 GHz, when the initial pH value was 6.0 or 8.0, but not 7.5. These results indicate the changes in the properties of water and its role in the effects of EMI of extremely high frequency. The marked effect of EMI on bacteria disappeared upon repeated irradiation for 1 h at a frequency of 51.8 or 53 GHz with an interval of 2 hours. This result indicates some compensatory mechanisms in bacteria.

Microfluidic size separation of cells and particles using a swinging bucket centrifuge.

PubMed

Yeo, Joo Chuan; Wang, Zhiping; Lim, Chwee Teck

2015-09-01

Biomolecular separation is crucial for downstream analysis. Separation technique mainly relies on centrifugal sedimentation. However, minuscule sample volume separation and extraction is difficult with conventional centrifuge. Furthermore, conventional centrifuge requires density gradient centrifugation which is laborious and time-consuming. To overcome this challenge, we present a novel size-selective bioparticles separation microfluidic chip on a swinging bucket minifuge. Size separation is achieved using passive pressure driven centrifugal fluid flows coupled with centrifugal force acting on the particles within the microfluidic chip. By adopting centrifugal microfluidics on a swinging bucket rotor, we achieved over 95% efficiency in separating mixed 20 μm and 2 μm colloidal dispersions from its liquid medium. Furthermore, by manipulating the hydrodynamic resistance, we performed size separation of mixed microbeads, achieving size efficiency of up to 90%. To further validate our device utility, we loaded spiked whole blood with MCF-7 cells into our microfluidic device and subjected it to centrifugal force for a mere duration of 10 s, thereby achieving a separation efficiency of over 75%. Overall, our centrifugal microfluidic device enables extremely rapid and label-free enrichment of different sized cells and particles with high efficiency.

Microfluidic size separation of cells and particles using a swinging bucket centrifuge

PubMed Central

Yeo, Joo Chuan; Wang, Zhiping; Lim, Chwee Teck

2015-01-01

Biomolecular separation is crucial for downstream analysis. Separation technique mainly relies on centrifugal sedimentation. However, minuscule sample volume separation and extraction is difficult with conventional centrifuge. Furthermore, conventional centrifuge requires density gradient centrifugation which is laborious and time-consuming. To overcome this challenge, we present a novel size-selective bioparticles separation microfluidic chip on a swinging bucket minifuge. Size separation is achieved using passive pressure driven centrifugal fluid flows coupled with centrifugal force acting on the particles within the microfluidic chip. By adopting centrifugal microfluidics on a swinging bucket rotor, we achieved over 95% efficiency in separating mixed 20 μm and 2 μm colloidal dispersions from its liquid medium. Furthermore, by manipulating the hydrodynamic resistance, we performed size separation of mixed microbeads, achieving size efficiency of up to 90%. To further validate our device utility, we loaded spiked whole blood with MCF-7 cells into our microfluidic device and subjected it to centrifugal force for a mere duration of 10 s, thereby achieving a separation efficiency of over 75%. Overall, our centrifugal microfluidic device enables extremely rapid and label-free enrichment of different sized cells and particles with high efficiency. PMID:26487900

3D graphene nanomaterials for binder-free supercapacitors: scientific design for enhanced performance.

PubMed

He, Shuijian; Chen, Wei

2015-04-28

Because of the excellent intrinsic properties, especially the strong mechanical strength, extraordinarily high surface area and extremely high conductivity, graphene is deemed as a versatile building block for fabricating functional materials for energy production and storage applications. In this article, the recent progress in the assembly of binder-free and self-standing graphene-based materials, as well as their application in supercapacitors are reviewed, including electrical double layer capacitors, pseudocapacitors, and asymmetric supercapacitors. Various fabrication strategies and the influence of structures on the capacitance performance of 3D graphene-based materials are discussed. We finally give concluding remarks and an outlook on the scientific design of binder-free and self-standing graphene materials for achieving better capacitance performance.

3D graphene nanomaterials for binder-free supercapacitors: scientific design for enhanced performance

NASA Astrophysics Data System (ADS)

He, Shuijian; Chen, Wei

2015-04-01

Because of the excellent intrinsic properties, especially the strong mechanical strength, extraordinarily high surface area and extremely high conductivity, graphene is deemed as a versatile building block for fabricating functional materials for energy production and storage applications. In this article, the recent progress in the assembly of binder-free and self-standing graphene-based materials, as well as their application in supercapacitors are reviewed, including electrical double layer capacitors, pseudocapacitors, and asymmetric supercapacitors. Various fabrication strategies and the influence of structures on the capacitance performance of 3D graphene-based materials are discussed. We finally give concluding remarks and an outlook on the scientific design of binder-free and self-standing graphene materials for achieving better capacitance performance.

Combustor materials requirements and status of ceramic matrix composites

NASA Technical Reports Server (NTRS)

Hecht, Ralph J.; Johnson, Andrew M.

1992-01-01

The HSCT combustor will be required to operate with either extremely rich or lean fuel/air ratios to reduce NO(x) emission. NASA High Speed Research (HSR) sponsored programs at Pratt & Whitney (P&W) and GE Aircraft Engines (GEAE) have been studying rich and lean burn combustor design approaches which are capable of achieving the aggressive HSCT NO(x) emission goals. In both of the combustor design approaches under study, high temperature (2400-3000 F) materials are necessary to meet the HSCT emission goals of 3-8 gm/kg. Currently available materials will not meet the projected requirements for the HSCT combustor. The development of new materials is an enabling technology for the successful introduction to service of the HSCT.

High temperature x-ray micro-tomography

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

MacDowell, Alastair A., E-mail: aamacdowell@lbl.gov; Barnard, Harold; Parkinson, Dilworth Y.

2016-07-27

There is increasing demand for 3D micro-scale time-resolved imaging of samples in realistic - and in many cases extreme environments. The data is used to understand material response, validate and refine computational models which, in turn, can be used to reduce development time for new materials and processes. Here we present the results of high temperature experiments carried out at the x-ray micro-tomography beamline 8.3.2 at the Advanced Light Source. The themes involve material failure and processing at temperatures up to 1750°C. The experimental configurations required to achieve the requisite conditions for imaging are described, with examples of ceramic matrixmore » composites, spacecraft ablative heat shields and nuclear reactor core Gilsocarbon graphite.« less

[Determination of process variable pH in solid-state fermentation by FT-NIR spectroscopy and extreme learning machine (ELM)].

PubMed

Liu, Guo-hai; Jiang, Hui; Xiao, Xia-hong; Zhang, Dong-juan; Mei, Cong-li; Ding, Yu-han

2012-04-01

Fourier transform near-infrared (FT-NIR) spectroscopy was attempted to determine pH, which is one of the key process parameters in solid-state fermentation of crop straws. First, near infrared spectra of 140 solid-state fermented product samples were obtained by near infrared spectroscopy system in the wavelength range of 10 000-4 000 cm(-1), and then the reference measurement results of pH were achieved by pH meter. Thereafter, the extreme learning machine (ELM) was employed to calibrate model. In the calibration model, the optimal number of PCs and the optimal number of hidden-layer nodes of ELM network were determined by the cross-validation. Experimental results showed that the optimal ELM model was achieved with 1040-1 topology construction as follows: R(p) = 0.961 8 and RMSEP = 0.104 4 in the prediction set. The research achievement could provide technological basis for the on-line measurement of the process parameters in solid-state fermentation.

Climate Change: A New Metric to Measure Changes in the Frequency of Extreme Temperatures using Record Data

NASA Technical Reports Server (NTRS)

Munasinghe, L.; Jun, T.; Rind, D. H.

2012-01-01

Consensus on global warming is the result of multiple and varying lines of evidence, and one key ramification is the increase in frequency of extreme climate events including record high temperatures. Here we develop a metric- called "record equivalent draws" (RED)-based on record high (low) temperature observations, and show that changes in RED approximate changes in the likelihood of extreme high (low) temperatures. Since we also show that this metric is independent of the specifics of the underlying temperature distributions, RED estimates can be aggregated across different climates to provide a genuinely global assessment of climate change. Using data on monthly average temperatures across the global landmass we find that the frequency of extreme high temperatures increased 10-fold between the first three decades of the last century (1900-1929) and the most recent decade (1999-2008). A more disaggregated analysis shows that the increase in frequency of extreme high temperatures is greater in the tropics than in higher latitudes, a pattern that is not indicated by changes in mean temperature. Our RED estimates also suggest concurrent increases in the frequency of both extreme high and extreme low temperatures during 2002-2008, a period when we observe a plateauing of global mean temperature. Using daily extreme temperature observations, we find that the frequency of extreme high temperatures is greater in the daily minimum temperature time-series compared to the daily maximum temperature time-series. There is no such observable difference in the frequency of extreme low temperatures between the daily minimum and daily maximum.

Treatment of Extreme Tuberculous Kyphosis Using Spinal Osteotomy and Halo-Pelvic Traction: A Case Report.

PubMed

Yu, Bin; Zhu, Ke; Zhao, Deng; Wang, Fei; Liang, Yijian

2016-02-01

A case report of treatment of extreme tuberculous kyphosis using spinal osteotomy and halopelvic traction. The aim of this study was to describe the process and outcome of treatment of a case with extreme tuberculous kyphosis using spine osteotomy and halo-pelvic traction. Spinal tuberculosis causes destruction, deformity, and paraplegia. Long-standing kyphosis may progress with growth in children, and produces respiratory insufficiency, and neurologic deficit. Surgery may help to prevent or reverse the neurological deterioration, while improving pulmonary function in cases with significant spinal deformity. Review of records and radiographs. A 24-year-old female with tuberculous angular kyphosis presented with bilateral lower extremities paresis and dyspnea. The vertebral bodies from T3 to T9 were severely destructed, with a Cobb's angle of 180°on radiographs. The total duration of distraction using halopelvic apparatus kept 10 months. During the duration of traction, the patient underwent a posterior release surgery because flexibility of the kyphosis was not sufficient. Pedicle subtraction osteotomy and pedicle screw fixation were performed to achieve final correction when the Cobb's angle decreased to about 80°. After the whole treatment of halopelvic traction and spine ostetomy, the patient's height increased nearly 30 cm, whereas the angular kyphosis was corrected to a Cobb's angle of 30°. The patient had no complication and neurological deterioration during the treatment. Correction angle and good sagittal balance were well maintained in the duration of 2 years' follow-up. The halo-pelvic apparatus produces high corrective forces applied over a long period, and it provides a slow and safe correction of deformity. In cases of extreme kyphotic deformity, halopelvic traction is an appropriate technique, while avoiding many serious complications from a rapid, one-stage correction. N/A.

Measurement Properties of the Lower Extremity Functional Scale: A Systematic Review.

PubMed

Mehta, Saurabh P; Fulton, Allison; Quach, Cedric; Thistle, Megan; Toledo, Cesar; Evans, Neil A

2016-03-01

Systematic review of measurement properties. Many primary studies have examined the measurement properties, such as reliability, validity, and sensitivity to change, of the Lower Extremity Functional Scale (LEFS) in different clinical populations. A systematic review summarizing these properties for the LEFS may provide an important resource. To locate and synthesize evidence on the measurement properties of the LEFS and to discuss the clinical implications of the evidence. A literature search was conducted in 4 databases (PubMed, MEDLINE, Embase, and CINAHL), using predefined search terms. Two reviewers performed a critical appraisal of the included studies using a standardized assessment form. A total of 27 studies were included in the review, of which 18 achieved a very good to excellent methodological quality level. The LEFS scores demonstrated excellent test-retest reliability (intraclass correlation coefficients ranging between 0.85 and 0.99) and demonstrated the expected relationships with measures assessing similar constructs (Pearson correlation coefficient values of greater than 0.7). The responsiveness of the LEFS scores was excellent, as suggested by consistently high effect sizes (greater than 0.8) in patients with different lower extremity conditions. Minimal detectable change at the 90% confidence level (MDC90) for the LEFS scores varied between 8.1 and 15.3 across different reassessment intervals in a wide range of patient populations. The pooled estimate of the MDC90 was 6 points and the minimal clinically important difference was 9 points in patients with lower extremity musculoskeletal conditions, which are indicative of true change and clinically meaningful change, respectively. The results of this review support the reliability, validity, and responsiveness of the LEFS scores for assessing functional impairment in a wide array of patient groups with lower extremity musculoskeletal conditions.

A High Performance Block Eigensolver for Nuclear Configuration Interaction Calculations

DOE PAGES

Aktulga, Hasan Metin; Afibuzzaman, Md.; Williams, Samuel; ...

2017-06-01

As on-node parallelism increases and the performance gap between the processor and the memory system widens, achieving high performance in large-scale scientific applications requires an architecture-aware design of algorithms and solvers. We focus on the eigenvalue problem arising in nuclear Configuration Interaction (CI) calculations, where a few extreme eigenpairs of a sparse symmetric matrix are needed. Here, we consider a block iterative eigensolver whose main computational kernels are the multiplication of a sparse matrix with multiple vectors (SpMM), and tall-skinny matrix operations. We then present techniques to significantly improve the SpMM and the transpose operation SpMM T by using themore » compressed sparse blocks (CSB) format. We achieve 3-4× speedup on the requisite operations over good implementations with the commonly used compressed sparse row (CSR) format. We develop a performance model that allows us to correctly estimate the performance of our SpMM kernel implementations, and we identify cache bandwidth as a potential performance bottleneck beyond DRAM. We also analyze and optimize the performance of LOBPCG kernels (inner product and linear combinations on multiple vectors) and show up to 15× speedup over using high performance BLAS libraries for these operations. The resulting high performance LOBPCG solver achieves 1.4× to 1.8× speedup over the existing Lanczos solver on a series of CI computations on high-end multicore architectures (Intel Xeons). We also analyze the performance of our techniques on an Intel Xeon Phi Knights Corner (KNC) processor.« less

Progress in extremely high brightness LED-based light sources

NASA Astrophysics Data System (ADS)

Hoelen, Christoph; Antonis, Piet; de Boer, Dick; Koole, Rolf; Kadijk, Simon; Li, Yun; Vanbroekhoven, Vincent; Van De Voorde, Patrick

2017-09-01

Although the maximum brightness of LEDs has been increasing continuously during the past decade, their luminance is still far from what is required for multiple applications that still rely on the high brightness of discharge lamps. In particular for high brightness applications with limited étendue, e.g. front projection, only very modest luminance values in the beam can be achieved with LEDs compared to systems based on discharge lamps or lasers. With dedicated architectures, phosphor-converted green LEDs for projection may achieve luminance values up to 200-300 Mnit. In this paper we report on the progress made in the development of light engines based on an elongated luminescent concentrator pumped by blue LEDs. This concept has recently been introduced to the market as ColorSpark High Lumen Density LED technology. These sources outperform the maximum brightness of LEDs by multiple factors. In LED front projection, green LEDs are the main limiting factor. With our green modules, we now have achieved peak luminance values of 2 Gnit, enabling LED-based projection systems with over 4000 ANSI lm. Extension of this concept to yellow and red light sources is presented. The light source efficiency has been increased considerably, reaching 45-60 lm/W for green under practical application conditions. The module architecture, beam shaping, and performance characteristics are reviewed, as well as system aspects. The performance increase, spectral range extensions, beam-shaping flexibility, and cost reductions realized with the new module architecture enable a breakthrough in LED-based projection systems and in a wide variety of other high brightness applications.

A High Performance Block Eigensolver for Nuclear Configuration Interaction Calculations

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

Aktulga, Hasan Metin; Afibuzzaman, Md.; Williams, Samuel

As on-node parallelism increases and the performance gap between the processor and the memory system widens, achieving high performance in large-scale scientific applications requires an architecture-aware design of algorithms and solvers. We focus on the eigenvalue problem arising in nuclear Configuration Interaction (CI) calculations, where a few extreme eigenpairs of a sparse symmetric matrix are needed. Here, we consider a block iterative eigensolver whose main computational kernels are the multiplication of a sparse matrix with multiple vectors (SpMM), and tall-skinny matrix operations. We then present techniques to significantly improve the SpMM and the transpose operation SpMM T by using themore » compressed sparse blocks (CSB) format. We achieve 3-4× speedup on the requisite operations over good implementations with the commonly used compressed sparse row (CSR) format. We develop a performance model that allows us to correctly estimate the performance of our SpMM kernel implementations, and we identify cache bandwidth as a potential performance bottleneck beyond DRAM. We also analyze and optimize the performance of LOBPCG kernels (inner product and linear combinations on multiple vectors) and show up to 15× speedup over using high performance BLAS libraries for these operations. The resulting high performance LOBPCG solver achieves 1.4× to 1.8× speedup over the existing Lanczos solver on a series of CI computations on high-end multicore architectures (Intel Xeons). We also analyze the performance of our techniques on an Intel Xeon Phi Knights Corner (KNC) processor.« less

High-speed uncooled MWIR hostile fire indication sensor

NASA Astrophysics Data System (ADS)

Zhang, L.; Pantuso, F. P.; Jin, G.; Mazurenko, A.; Erdtmann, M.; Radhakrishnan, S.; Salerno, J.

2011-06-01

Hostile fire indication (HFI) systems require high-resolution sensor operation at extremely high speeds to capture hostile fire events, including rocket-propelled grenades, anti-aircraft artillery, heavy machine guns, anti-tank guided missiles and small arms. HFI must also be conducted in a waveband with large available signal and low background clutter, in particular the mid-wavelength infrared (MWIR). The shortcoming of current HFI sensors in the MWIR is the bandwidth of the sensor is not sufficient to achieve the required frame rate at the high sensor resolution. Furthermore, current HFI sensors require cryogenic cooling that contributes to size, weight, and power (SWAP) in aircraft-mounted applications where these factors are at a premium. Based on its uncooled photomechanical infrared imaging technology, Agiltron has developed a low-SWAP, high-speed MWIR HFI sensor that breaks the bandwidth bottleneck typical of current infrared sensors. This accomplishment is made possible by using a commercial-off-the-shelf, high-performance visible imager as the readout integrated circuit and physically separating this visible imager from the MWIR-optimized photomechanical sensor chip. With this approach, we have achieved high-resolution operation of our MWIR HFI sensor at 1000 fps, which is unprecedented for an uncooled infrared sensor. We have field tested our MWIR HFI sensor for detecting all hostile fire events mentioned above at several test ranges under a wide range of environmental conditions. The field testing results will be presented.

Poverty eradication in a carbon constrained world.

PubMed

Hubacek, Klaus; Baiocchi, Giovanni; Feng, Kuishuang; Patwardhan, Anand

2017-10-24

The UN Framework Convention on Climate Change aims to keep warming below 2 °C while recognizing developing countries' right to eradicate extreme poverty. Poverty eradication is also the first of the Sustainable Development Goals. This paper investigates potential consequences for climate targets of achieving poverty eradication. We find that eradicating extreme poverty, i.e., moving people to an income above $1.9 purchasing power parity (PPP) a day, does not jeopardize the climate target even in the absence of climate policies and with current technologies. On the other hand, bringing everybody to a still modest expenditure level of at least $2.97 PPP would have long-term consequences on achieving emission targets. Compared to the reference mitigation pathway, eradicating extreme poverty increases the effort by 2.8% whereas bringing everybody to at least $2.97 PPP would increase the required mitigation rate by 27%. Given that the top 10% global income earners are responsible for 36% of the current carbon footprint of households; the discourse should address income distribution and the carbon intensity of lifestyles.

Focal overlap gating in velocity map imaging to achieve high signal-to-noise ratio in photo-ion pump-probe experiments

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

Shivaram, Niranjan; Champenois, Elio G.; Cryan, James P.

We demonstrate a technique in velocity map imaging (VMI) that allows spatial gating of the laser focal overlap region in time resolved pump-probe experiments. This significantly enhances signal-to-noise ratio by eliminating background signal arising outside the region of spatial overlap of pump and probe beams. This enhancement is achieved by tilting the laser beams with respect to the surface of the VMI electrodes which creates a gradient in flight time for particles born at different points along the beam. By suitably pulsing our microchannel plate detector, we can select particles born only where the laser beams overlap. Furthermore, this spatialmore » gating in velocity map imaging can benefit nearly all photo-ion pump-probe VMI experiments especially when extreme-ultraviolet light or X-rays are involved which produce large background signals on their own.« less

Flash Joule heating for ductilization of metallic glasses

NASA Astrophysics Data System (ADS)

Okulov, I. V.; Soldatov, I. V.; Sarmanova, M. F.; Kaban, I.; Gemming, T.; Edström, K.; Eckert, J.

2015-07-01

Metallic glasses (MGs) inherit their amorphous structure from the liquid state, which predetermines their ability to withstand high loads approaching the theoretical limit. However, the absence of slip systems makes them very sensitive to the type of loading and extremely brittle in tension. The latter can be improved by precipitation of ductile crystals, which suppress a catastrophic propagation of shear bands in a glassy matrix. Here we report a novel approach to obtain MG-matrix composites with tensile ductility by flash Joule heating applied to Cu47.5Zr47.5Al5 (at.%) metallic glass. This homogeneous, volumetric and controllable rapid heat treatment allows achieving uniformly distributed metastable B2 CuZr crystals in the glassy matrix. It results in a significant tensile strain of 6.8+/-0.5%. Moreover, optimized adjustment of the heat-treatment conditions enables tuning of microstructure to achieve desired mechanical properties.

Explosively driven hypervelocity launcher: Second-stage augmentation techniques

NASA Technical Reports Server (NTRS)

Baum, D. W.

1973-01-01

The results are described of a continuing study aimed at developing a two-stage explosively driven hypervelocity launcher capable of achieving projectile velocities between 15 and 20 km/sec. The testing and evaluation of a new cylindrical impact technique for collapsing the barrel of two-stage launcher are reported. Previous two-stage launchers have been limited in ultimate performance by incomplete barrel collapse behind the projectile. The cylindrical impact technique explosively collapses a steel tube concentric with and surrounding the barrel of the launcher. The impact of the tube on the barrel produces extremely high stresses which cause the barrel to collapse. The collapse rate can be adjusted by appropriate variation of the explosive charge and tubing parameters. Launcher experiments demonstrated that the technique did achieve complete barrel collapse and form a second-stage piston. However, jetting occurred in the barrel collapse process and was responsible for severe projectile damage.

Isotropic Huygens dipoles and multipoles with colloidal particles

NASA Astrophysics Data System (ADS)

Dezert, Romain; Richetti, Philippe; Baron, Alexandre

2017-11-01

Huygens sources are elements that scatter light in the forward direction as used in the Huygens-Fresnel principle. They have remained fictitious until recently when experimental systems have been fabricated. In this Rapid Communication, we propose isotropic meta-atoms that act as Huygens sources. Using clusters of plasmonic or dielectric colloidal particles, Huygens dipoles that resonate at visible frequencies can be achieved with scattering cross sections as high as five times the geometric cross section of the particle surpassing anything achievable with a hypothetical simple spherical particle. Examples are given that predict extremely broadband scattering in the forward direction over a 1000 nm wavelength range at optical frequencies. These systems are important to the fields of nanoantennas, metamaterials, and wave physics in general as well as any application that requires local control over the radiation properties of a system as in solar cells or biosensing.

Compressed air-assisted solvent extraction (CASX) for metal removal.

PubMed

Li, Chi-Wang; Chen, Yi-Ming; Hsiao, Shin-Tien

2008-03-01

A novel process, compressed air-assisted solvent extraction (CASX), was developed to generate micro-sized solvent-coated air bubbles (MSAB) for metal extraction. Through pressurization of solvent with compressed air followed by releasing air-oversaturated solvent into metal-containing wastewater, MSAB were generated instantaneously. The enormous surface area of MSAB makes extraction process extremely fast and achieves very high aqueous/solvent weight ratio (A/S ratio). CASX process completely removed Cr(VI) from acidic electroplating wastewater under A/S ratio of 115 and extraction time of less than 10s. When synthetic wastewater containing Cd(II) of 50mgl(-1) was treated, A/S ratios of higher than 714 and 1190 could be achieved using solvent with extractant/diluent weight ratio of 1:1 and 5:1, respectively. Also, MSAB have very different physical properties, such as size and density, compared to the emulsified solvent droplets, making separation and recovery of solvent from treated effluent very easy.

A review on ductile mode cutting of brittle materials

NASA Astrophysics Data System (ADS)

Antwi, Elijah Kwabena; Liu, Kui; Wang, Hao

2018-06-01

Brittle materials have been widely employed for industrial applications due to their excellent mechanical, optical, physical and chemical properties. But obtaining smooth and damage-free surface on brittle materials by traditional machining methods like grinding, lapping and polishing is very costly and extremely time consuming. Ductile mode cutting is a very promising way to achieve high quality and crack-free surfaces of brittle materials. Thus the study of ductile mode cutting of brittle materials has been attracting more and more efforts. This paper provides an overview of ductile mode cutting of brittle materials including ductile nature and plasticity of brittle materials, cutting mechanism, cutting characteristics, molecular dynamic simulation, critical undeformed chip thickness, brittle-ductile transition, subsurface damage, as well as a detailed discussion of ductile mode cutting enhancement. It is believed that ductile mode cutting of brittle materials could be achieved when both crack-free and no subsurface damage are obtained simultaneously.

[Nursing motivation leadership].

PubMed

Chen, Ia-Ling; Hung, Chich-Hsiu

2007-02-01

The concept of "patients treated as guests" is emphasized in today's medical service and patient-center nursing care. However, with rapid changes in health insurance and hospital accreditation systems as well as increasing consumer awareness, the nurse manager must both efficiently relieve the working pressure of nurses and motivate them. However, it would be an extreme challenge for nurse managers to build a team in which each member works in a self-fulfilling work environment and achieves a high quality of care. This article presents several theories and techniques that relate to motivation strategies. These strategies can serve as a guide and a reference for nurse managers to inspire teamwork and raise morale. It can be expected that increasing nurse satisfaction, performance, and care quality will decrease turnover and desertion rates. Hopefully, this article will assist nurse managers to become better leaders and to achieve success in providing efficient services and good of nursing care quality.

Repeatability and reproducibility of intracellular molar concentration assessed by synchrotron-based x-ray fluorescence microscopy

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

Merolle, L., E-mail: lucia.merolle@elettra.eu; Gianoncelli, A.; Malucelli, E., E-mail: emil.malucelli@unibo.it

2016-01-28

Elemental analysis of biological sample can give information about content and distribution of elements essential for human life or trace elements whose absence is the cause of abnormal biological function or development. However, biological systems contain an ensemble of cells with heterogeneous chemistry and elemental content; therefore, accurate characterization of samples with high cellular heterogeneity may only be achieved by analyzing single cells. Powerful methods in molecular biology are abundant, among them X-Ray microscopy based on synchrotron light source has gaining increasing attention thanks to its extremely sensitivity. However, reproducibility and repeatability of these measurements is one of the majormore » obstacles in achieving a statistical significance in single cells population analysis. In this study, we compared the elemental content of human colon adenocarcinoma cells obtained by three distinct accesses to synchrotron radiation light.« less

Vacuum deposition of iridium on large astronomical mirrors for use in the far UV

NASA Technical Reports Server (NTRS)

Herzig, H.; Spencer, R. S.

1982-01-01

An iridium coating has been deposited by electron-beam evaporation on a 0.91-m mirror which serves as the telescope primary of a sounding rocket instrument for far-UV spectrometry. The evaporation was carried out by applying 8 kV at 400 mA to the electron gun. Zone refined Ir of 99.99% purity was used, and the electron beam was electromagnetically swept over the surface of the evaporant. Under these conditions, deposition rates of 0.55 A/sec were achieved. The reflectance distribution achieved at a wavelength of 584 A was extremely uniform; the mean reflectance was 21.2% with a standard deviation of only 0.3%. This represents a substantial improvement over Al + MgF2 and Al + LiF coatings for applications involving multiple reflections and weak signals, as might be expected in a high-resolution spectrograph studying distant celestial objects.

Focal overlap gating in velocity map imaging to achieve high signal-to-noise ratio in photo-ion pump-probe experiments

DOE PAGES

Shivaram, Niranjan; Champenois, Elio G.; Cryan, James P.; ...

2016-12-19

We demonstrate a technique in velocity map imaging (VMI) that allows spatial gating of the laser focal overlap region in time resolved pump-probe experiments. This significantly enhances signal-to-noise ratio by eliminating background signal arising outside the region of spatial overlap of pump and probe beams. This enhancement is achieved by tilting the laser beams with respect to the surface of the VMI electrodes which creates a gradient in flight time for particles born at different points along the beam. By suitably pulsing our microchannel plate detector, we can select particles born only where the laser beams overlap. Furthermore, this spatialmore » gating in velocity map imaging can benefit nearly all photo-ion pump-probe VMI experiments especially when extreme-ultraviolet light or X-rays are involved which produce large background signals on their own.« less

Methane Leaks from Natural Gas Systems Follow Extreme Distributions.

PubMed

Brandt, Adam R; Heath, Garvin A; Cooley, Daniel

2016-11-15

Future energy systems may rely on natural gas as a low-cost fuel to support variable renewable power. However, leaking natural gas causes climate damage because methane (CH 4 ) has a high global warming potential. In this study, we use extreme-value theory to explore the distribution of natural gas leak sizes. By analyzing ∼15 000 measurements from 18 prior studies, we show that all available natural gas leakage data sets are statistically heavy-tailed, and that gas leaks are more extremely distributed than other natural and social phenomena. A unifying result is that the largest 5% of leaks typically contribute over 50% of the total leakage volume. While prior studies used log-normal model distributions, we show that log-normal functions poorly represent tail behavior. Our results suggest that published uncertainty ranges of CH 4 emissions are too narrow, and that larger sample sizes are required in future studies to achieve targeted confidence intervals. Additionally, we find that cross-study aggregation of data sets to increase sample size is not recommended due to apparent deviation between sampled populations. Understanding the nature of leak distributions can improve emission estimates, better illustrate their uncertainty, allow prioritization of source categories, and improve sampling design. Also, these data can be used for more effective design of leak detection technologies.

Multiclass Classification for the Differential Diagnosis on the ADHD Subtypes Using Recursive Feature Elimination and Hierarchical Extreme Learning Machine: Structural MRI Study

PubMed Central

Qureshi, Muhammad Naveed Iqbal; Min, Beomjun; Jo, Hang Joon; Lee, Boreom

2016-01-01

The classification of neuroimaging data for the diagnosis of certain brain diseases is one of the main research goals of the neuroscience and clinical communities. In this study, we performed multiclass classification using a hierarchical extreme learning machine (H-ELM) classifier. We compared the performance of this classifier with that of a support vector machine (SVM) and basic extreme learning machine (ELM) for cortical MRI data from attention deficit/hyperactivity disorder (ADHD) patients. We used 159 structural MRI images of children from the publicly available ADHD-200 MRI dataset. The data consisted of three types, namely, typically developing (TDC), ADHD-inattentive (ADHD-I), and ADHD-combined (ADHD-C). We carried out feature selection by using standard SVM-based recursive feature elimination (RFE-SVM) that enabled us to achieve good classification accuracy (60.78%). In this study, we found the RFE-SVM feature selection approach in combination with H-ELM to effectively enable the acquisition of high multiclass classification accuracy rates for structural neuroimaging data. In addition, we found that the most important features for classification were the surface area of the superior frontal lobe, and the cortical thickness, volume, and mean surface area of the whole cortex. PMID:27500640

So Small, So Loud: Extremely High Sound Pressure Level from a Pygmy Aquatic Insect (Corixidae, Micronectinae)

PubMed Central

Sueur, Jérôme; Mackie, David; Windmill, James F. C.

2011-01-01

To communicate at long range, animals have to produce intense but intelligible signals. This task might be difficult to achieve due to mechanical constraints, in particular relating to body size. Whilst the acoustic behaviour of large marine and terrestrial animals has been thoroughly studied, very little is known about the sound produced by small arthropods living in freshwater habitats. Here we analyse for the first time the calling song produced by the male of a small insect, the water boatman Micronecta scholtzi. The song is made of three distinct parts differing in their temporal and amplitude parameters, but not in their frequency content. Sound is produced at 78.9 (63.6–82.2) SPL rms re 2.10−5 Pa with a peak at 99.2 (85.7–104.6) SPL re 2.10−5 Pa estimated at a distance of one metre. This energy output is significant considering the small size of the insect. When scaled to body length and compared to 227 other acoustic species, the acoustic energy produced by M. scholtzi appears as an extreme value, outperforming marine and terrestrial mammal vocalisations. Such an extreme display may be interpreted as an exaggerated secondary sexual trait resulting from a runaway sexual selection without predation pressure. PMID:21698252

So small, so loud: extremely high sound pressure level from a pygmy aquatic insect (Corixidae, Micronectinae).

PubMed

Sueur, Jérôme; Mackie, David; Windmill, James F C

2011-01-01

To communicate at long range, animals have to produce intense but intelligible signals. This task might be difficult to achieve due to mechanical constraints, in particular relating to body size. Whilst the acoustic behaviour of large marine and terrestrial animals has been thoroughly studied, very little is known about the sound produced by small arthropods living in freshwater habitats. Here we analyse for the first time the calling song produced by the male of a small insect, the water boatman Micronecta scholtzi. The song is made of three distinct parts differing in their temporal and amplitude parameters, but not in their frequency content. Sound is produced at 78.9 (63.6-82.2) SPL rms re 2.10(-5) Pa with a peak at 99.2 (85.7-104.6) SPL re 2.10(-5) Pa estimated at a distance of one metre. This energy output is significant considering the small size of the insect. When scaled to body length and compared to 227 other acoustic species, the acoustic energy produced by M. scholtzi appears as an extreme value, outperforming marine and terrestrial mammal vocalisations. Such an extreme display may be interpreted as an exaggerated secondary sexual trait resulting from a runaway sexual selection without predation pressure.

Extreme Toughening of Soft Materials with Liquid Metal.

PubMed

Kazem, Navid; Bartlett, Michael D; Majidi, Carmel

2018-05-01

Soft and tough materials are critical for engineering applications in medical devices, stretchable and wearable electronics, and soft robotics. Toughness in synthetic materials is mostly accomplished by increasing energy dissipation near the crack tip with various energy dissipation techniques. However, bio-materials exhibit extreme toughness by combining multi-scale energy dissipation with the ability to deflect and blunt an advancing crack tip. Here, we demonstrate a synthetic materials architecture that also exhibits multi-modal toughening, whereby embedding a suspension of micron sized and highly deformable liquid metal (LM) droplets inside a soft elastomer, the fracture energy dramatically increases by up to 50x (from 250 ± 50 J m -2 to 11,900 ± 2600 J m -2 ) over an unfilled polymer. For some LM-embedded elastomer (LMEE) compositions, the toughness is measured to be 33,500 ± 4300 J m -2 , which far exceeds the highest value previously reported for a soft elastic material. This extreme toughening is achieved by (i) increasing energy dissipation, (ii) adaptive crack movement, and (iii) effective elimination of the crack tip. Such properties arise from the deformability of the LM inclusions during loading, providing a new mechanism to not only prevent crack initiation, but also resist the propagation of existing tears for ultra tough, soft materials. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Methane Leaks from Natural Gas Systems Follow Extreme Distributions

DOE PAGES

Brandt, Adam R.; Heath, Garvin A.; Cooley, Daniel

2016-10-14

Future energy systems may rely on natural gas as a low-cost fuel to support variable renewable power. However, leaking natural gas causes climate damage because methane (CH 4) has a high global warming potential. In this study, we use extreme-value theory to explore the distribution of natural gas leak sizes. By analyzing ~15,000 measurements from 18 prior studies, we show that all available natural gas leakage datasets are statistically heavy-tailed, and that gas leaks are more extremely distributed than other natural and social phenomena. A unifying result is that the largest 5% of leaks typically contribute over 50% of themore » total leakage volume. While prior studies used lognormal model distributions, we show that lognormal functions poorly represent tail behavior. Our results suggest that published uncertainty ranges of CH 4 emissions are too narrow, and that larger sample sizes are required in future studies to achieve targeted confidence intervals. Additionally, we find that cross-study aggregation of datasets to increase sample size is not recommended due to apparent deviation between sampled populations. Finally, understanding the nature of leak distributions can improve emission estimates, better illustrate their uncertainty, allow prioritization of source categories, and improve sampling design. Also, these data can be used for more effective design of leak detection technologies.« less

Picometer stable scan mechanism for gravitational wave detection in space: LISA PAAM

NASA Astrophysics Data System (ADS)

Pijnenburg, J. A. C. M.; Rijnveld, N.

2017-11-01

Detection and observation of gravitational waves requires extreme stability in the frequency range 0.03 mHz to 1 Hz. The Laser Interferometer Space Antenna (LISA) mission will attain this by creating a giant interferometer in space, based on free floating proof masses in three spacecrafts. Due to orbit evolution and time delay in the interferometer arms, the direction of transmitted light changes. To solve this problem, a picometer stable Point-Ahead Angle Mechanism (PAAM) was designed, realized and successfully tested. The PAAM concept is based on a rotatable mirror. The critical requirements are the contribution to the optical path length (less than 1.4 pm / rt Hz) and the angular jitter (less than 8 nrad / rt Hz). Extreme dimensional stability is achieved by manufacturing a monolithical Haberland hinge mechanism out of Ti6Al4V, through high precision wire erosion. Extreme thermal stability is realized by placing the thermal center on the surface of the mirror. Because of piezo actuator noise and leakage, the PAAM has to be controlled in closed-loop. To meet the requirements in the low frequencies, an active target capacitance-to-digital converter is used. Interferometric measurements with a triangular resonant cavity in vacuum proved that the PAAM meets the requirements.

Methane Leaks from Natural Gas Systems Follow Extreme Distributions

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

Brandt, Adam R.; Heath, Garvin A.; Cooley, Daniel

Future energy systems may rely on natural gas as a low-cost fuel to support variable renewable power. However, leaking natural gas causes climate damage because methane (CH 4) has a high global warming potential. In this study, we use extreme-value theory to explore the distribution of natural gas leak sizes. By analyzing ~15,000 measurements from 18 prior studies, we show that all available natural gas leakage datasets are statistically heavy-tailed, and that gas leaks are more extremely distributed than other natural and social phenomena. A unifying result is that the largest 5% of leaks typically contribute over 50% of themore » total leakage volume. While prior studies used lognormal model distributions, we show that lognormal functions poorly represent tail behavior. Our results suggest that published uncertainty ranges of CH 4 emissions are too narrow, and that larger sample sizes are required in future studies to achieve targeted confidence intervals. Additionally, we find that cross-study aggregation of datasets to increase sample size is not recommended due to apparent deviation between sampled populations. Finally, understanding the nature of leak distributions can improve emission estimates, better illustrate their uncertainty, allow prioritization of source categories, and improve sampling design. Also, these data can be used for more effective design of leak detection technologies.« less

Performance Study of the First 2D Prototype of Vertically Integrated Pattern Recognition Associative Memory (VIPRAM)

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

Deptuch, Gregory; Hoff, James; Jindariani, Sergo

Extremely fast pattern recognition capabilities are necessary to find and fit billions of tracks at the hardware trigger level produced every second anticipated at high luminosity LHC (HL-LHC) running conditions. Associative Memory (AM) based approaches for fast pattern recognition have been proposed as a potential solution to the tracking trigger. However, at the HL-LHC, there is much less time available and speed performance must be improved over previous systems while maintaining a comparable number of patterns. The Vertically Integrated Pattern Recognition Associative Memory (VIPRAM) Project aims to achieve the target pattern density and performance goal using 3DIC technology. The firstmore » step taken in the VIPRAM work was the development of a 2D prototype (protoVIPRAM00) in which the associative memory building blocks were designed to be compatible with the 3D integration. In this paper, we present the results from extensive performance studies of the protoVIPRAM00 chip in both realistic HL-LHC and extreme conditions. Results indicate that the chip operates at the design frequency of 100 MHz with perfect correctness in realistic conditions and conclude that the building blocks are ready for 3D stacking. We also present performance boundary characterization of the chip under extreme conditions.« less

Deep-Learning Technique To Convert a Crude Piezoresistive Carbon Nanotube-Ecoflex Composite Sheet into a Smart, Portable, Disposable, and Extremely Flexible Keypad.

PubMed

Lee, Jin-Woong; Chung, Jiyong; Cho, Min-Young; Timilsina, Suman; Sohn, Keemin; Kim, Ji Sik; Sohn, Kee-Sun

2018-06-20

An extremely simple bulk sheet made of a piezoresistive carbon nanotube (CNT)-Ecoflex composite can act as a smart keypad that is portable, disposable, and flexible enough to be carried crushed inside the pocket of a pair of trousers. Both a rigid-button-imbedded, rollable (or foldable) pad and a patterned flexible pad have been introduced for use as portable keyboards. Herein, we suggest a bare, bulk, macroscale piezoresistive sheet as a replacement for these complex devices that are achievable only through high-cost fabrication processes such as patterning-based coating, printing, deposition, and mounting. A deep-learning technique based on deep neural networks (DNN) enables this extremely simple bulk sheet to play the role of a smart keypad without the use of complicated fabrication processes. To develop this keypad, instantaneous electrical resistance change was recorded at several locations on the edge of the sheet along with the exact information on the touch position and pressure for a huge number of random touches. The recorded data were used for training a DNN model that could eventually act as a brain for a simple sheet-type keypad. This simple sheet-type keypad worked perfectly and outperformed all of the existing portable keypads in terms of functionality, flexibility, disposability, and cost.

Multiclass Classification for the Differential Diagnosis on the ADHD Subtypes Using Recursive Feature Elimination and Hierarchical Extreme Learning Machine: Structural MRI Study.

PubMed

Qureshi, Muhammad Naveed Iqbal; Min, Beomjun; Jo, Hang Joon; Lee, Boreom

2016-01-01

The classification of neuroimaging data for the diagnosis of certain brain diseases is one of the main research goals of the neuroscience and clinical communities. In this study, we performed multiclass classification using a hierarchical extreme learning machine (H-ELM) classifier. We compared the performance of this classifier with that of a support vector machine (SVM) and basic extreme learning machine (ELM) for cortical MRI data from attention deficit/hyperactivity disorder (ADHD) patients. We used 159 structural MRI images of children from the publicly available ADHD-200 MRI dataset. The data consisted of three types, namely, typically developing (TDC), ADHD-inattentive (ADHD-I), and ADHD-combined (ADHD-C). We carried out feature selection by using standard SVM-based recursive feature elimination (RFE-SVM) that enabled us to achieve good classification accuracy (60.78%). In this study, we found the RFE-SVM feature selection approach in combination with H-ELM to effectively enable the acquisition of high multiclass classification accuracy rates for structural neuroimaging data. In addition, we found that the most important features for classification were the surface area of the superior frontal lobe, and the cortical thickness, volume, and mean surface area of the whole cortex.

Gastric B-cell mucosa associated lymphoid tissue lymphoma: a clinicopathological study in 56 patients.

PubMed Central

Castrillo, J M; Montalban, C; Obeso, G; Piris, M A; Rivas, M C

1992-01-01

Clinico-pathological features of 56 patients with primary gastric lymphoma were evaluated retrospectively. All cases were regraded according to a classification of Isaacson et al into high grade and low grade B-cell mucosa associated lymphoid tissue lymphoma. A third group of mixed grade was recognised in 11 patients with low grade who also had occasional areas of high grade. Low grade and mixed grade patients had a 100% actuarial survival at 156 months, which was significantly better (p < 0.01) than that of 52% for patients with high grade disease. Different treatment methods--surgery, chemotherapy, or a combination of both--did not significantly affect survival. Low grade tumours occurred mainly in men with a history of several years, and who presented with non-specific gastric symptoms without remarkable exploratory or laboratory findings: most patients were in stage IE-IIE and achieved remission and cure. High grade can have a shorter history, systemic symptoms, abnormal exploratory and laboratory findings, gastric tumour masses, stage IV disease, and a worse outcome. The only significant prognostic factors for survival were the type of lymphoma and stage IV disease. These findings support the Isaacson classification system which separates two extreme groups of gastric lymphomas with different morphology, behaviour, and outcome. The presence of limited areas of high grade in a specimen showing low grade does not change the outcome but suggests that primary gastric lymphoma forms a continuum between these extreme types. PMID:1446850

Assessing present and future climate changes in Siberia and their regional socioeconomic consequences using a web-based big data geoprocessing platform

NASA Astrophysics Data System (ADS)

Alexeev, V. A.; Gordov, E. P.

2016-12-01

Recently initiated collaborative research project is presented. Its main objective is to develop high spatial and temporal resolution datasets for studying the ongoing and future climate changes in Siberia, caused by global and regional processes in the atmosphere and the ocean. This goal will be achieved by using a set of regional and global climate models for the analysis of the mechanisms of climate change and quantitative assessment of changes in key climate variables, including analysis of extreme weather and climate events and their dynamics, evaluation of the frequency, amplitude and the risks caused by the extreme events in the region. The main practical application of the project is to provide experts, stakeholders and the public with quantitative information about the future climate change in Siberia obtained on the base of a computational web- geoinformation platform. The thematic platform will be developed in order to facilitate processing and analysis of high resolution georeferenced datasets that will be delivered and made available to scientific community, policymakes and other end users as a result of the project. Software packages will be developed to implement calculation of various climatological indicators in order to characterize and diagnose climate change and its dynamics, as well as to archive results in digital form of electronic maps (GIS layers). By achieving these goals the project will provide science based tools necessary for developing mitigation measures for adapting to climate change and reducing negative impact on the population and infrastructure of the region. Financial support of the computational web- geoinformation platform prototype development by the RF Ministry of Education and Science under Agreement 14.613.21.0037 (RFMEFI61315X0037) is acknowledged.

Pyramiding genes and alleles for improving energy cane biomass yield

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

Ming, Ray; Nagai, Chifumi; Yu, Qingyi

The overall goal of this project is to identify genes and gene interaction networks contributed to the extreme segregants with 30 folds biomass yield difference in sugarcane F2 populations. Towards achieving this goal, yield trials of 108 F2 extreme segregants from S. officinarum LA Purple and S. robustum MOL5829 (LM population) were carried out in two locations in three years. A yield trial of the second F2 population from S. officinarum LA Purple and S. spontaneum US56-14-4 (LU population) was installed in the summer of 2014 and the first set of yield component data was collected. For genotyping, transcriptomes frommore » leaves and stalks of 70 extreme segregants of the LM F2 population and 119 individuals of the LU F2 populations were sequenced. The genomes of 91 F1 individuals from the LM populations are being sequenced to construct ultra-high density genetic maps for each of the two parents for both assisting the LA Purple genome assembling and for testing a hypothesis of female restitution. The genomes of 110 F2 individuals from single F1 in the LU population, a different set from the 119 F2 individuals used for transcriptome sequencing, are being sequenced for mapping genes and QTLs affecting biomass yield and for testing a hypothesis of female restitution. Gene expression analysis between extreme segregants of high and low biomass yield showed up-regulation of cellulose synthase, cellulose, and xylan synthase in high biomass yield segregants among 3,274 genes differentially expressed between the two extremes. Our transcriptome results revealed not only the increment of cell wall biosynthesis pathway is essential, but the rapid turnover of certain cell wall polymers as well as carbohydrate partitioning are also important for recycling and energy conservation during rapid cell growth in high biomass sugarcane. Seventeen differentially expressed genes in auxin, one in ethylene and one in gibberellin related signaling and biosynthesis pathways were identified, which could potentially regulate biomass yield. Differentially expressed genes, PIF3 and EIL5, involved in gibberellin and ethylene pathway could play an important role in biomass accumulation. Differential gene expression analysis was also carried out on the LU population. High-biomass yield was mainly determined by assimilation of carbon in source tissues. The high-level expression of fermentative genes in the low-biomass group was likely induced by their low-energy status. The haploid (tetraploid) genome of S. spontanium AP85-441 was sequenced with chromosome level assembly and allele defined annotation. This reference genome along with the upcoming S. officinarum genome will allow us to identify genes and alleles contributed to biomass yield.« less

On the Path to SunShot - The Role of Advancements in Solar Photovoltaic Efficiency, Reliability, and Costs

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

Woodhouse, Michael; Jones-Albertus, Rebecca; Feldman, David

2016-05-01

Although tremendous progress has been made in reducing the cost of PV systems, additional LCOE reductions of 40%–50% between 2015 and 2020 will be required to reach the SunShot Initiative’s targets (see Woodhouse et al. 2016). Understanding the tradeoffs between installed prices and other PV system characteristics—such as module efficiency, module degradation rate, and system lifetime—are vital. For example, with 29%-efficient modules and high reliability (a 50-year lifetime and a 0.2%/year module degradation rate), a residential PV system could achieve the SunShot LCOE goal with modules priced at almost $1.20/W. But change the lifetime to 10 years and the degradationmore » rate to 2%/year, and the system would need those very high-efficiency modules at zero cost to achieve the same LCOE. Although these examples are extreme, they serve to illustrate the wide range of technological combinations that could help drive PV toward the LCOE goals. SunShot’s PV roadmaps illustrate specific potential pathways to the target cost reductions.« less

A non-volatile organic electrochemical device as a low-voltage artificial synapse for neuromorphic computing

DOE PAGES

van de Burgt, Yoeri; Lubberman, Ewout; Fuller, Elliot J.; ...

2017-02-20

The brain is capable of massively parallel information processing while consuming only ~1- 100 fJ per synaptic event. Inspired by the efficiency of the brain, CMOS-based neural architectures and memristors are being developed for pattern recognition and machine learning. However, the volatility, design complexity and high supply voltages for CMOS architectures, and the stochastic and energy-costly switching of memristors complicate the path to achieve the interconnectivity, information density, and energy efficiency of the brain using either approach. Here we describe an electrochemical neuromorphic organic device (ENODe) operating with a fundamentally different mechanism from existing memristors. ENODe switches at low energymore » (<10 pJ for 10 3 μm 2 devices) and voltage, displays >500 distinct, non-volatile conductance states within a ~1 V range, and achieves high classification accuracy when implemented in neural network simulations. Plastic ENODEs are also fabricated on flexible substrates enabling the integration of neuromorphic functionality in stretchable electronic systems. Mechanical flexibility makes ENODes compatible with 3D architectures, opening a path towards extreme interconnectivity comparable to the human brain.« less

Laissez-Faire : Fully Asymmetric Backscatter Communication

PubMed Central

Hu, Pan; Zhang, Pengyu; Ganesan, Deepak

2016-01-01

Backscatter provides dual-benefits of energy harvesting and low-power communication, making it attractive to a broad class of wireless sensors. But the design of a protocol that enables extremely power-efficient radios for harvesting-based sensors as well as high-rate data transfer for data-rich sensors presents a conundrum. In this paper, we present a new fully asymmetric backscatter communication protocol where nodes blindly transmit data as and when they sense. This model enables fully flexible node designs, from extraordinarily power-efficient backscatter radios that consume barely a few micro-watts to high-throughput radios that can stream at hundreds of Kbps while consuming a paltry tens of micro-watts. The challenge, however, lies in decoding concurrent streams at the reader, which we achieve using a novel combination of time-domain separation of interleaved signal edges, and phase-domain separation of colliding transmissions. We provide an implementation of our protocol, LF-Backscatter, and show that it can achieve an order of magnitude or more improvement in throughput, latency and power over state-of-art alternatives. PMID:28286885

A non-volatile organic electrochemical device as a low-voltage artificial synapse for neuromorphic computing

NASA Astrophysics Data System (ADS)

van de Burgt, Yoeri; Lubberman, Ewout; Fuller, Elliot J.; Keene, Scott T.; Faria, Grégorio C.; Agarwal, Sapan; Marinella, Matthew J.; Alec Talin, A.; Salleo, Alberto

2017-04-01

The brain is capable of massively parallel information processing while consuming only ~1-100 fJ per synaptic event. Inspired by the efficiency of the brain, CMOS-based neural architectures and memristors are being developed for pattern recognition and machine learning. However, the volatility, design complexity and high supply voltages for CMOS architectures, and the stochastic and energy-costly switching of memristors complicate the path to achieve the interconnectivity, information density, and energy efficiency of the brain using either approach. Here we describe an electrochemical neuromorphic organic device (ENODe) operating with a fundamentally different mechanism from existing memristors. ENODe switches at low voltage and energy (<10 pJ for 103 μm2 devices), displays >500 distinct, non-volatile conductance states within a ~1 V range, and achieves high classification accuracy when implemented in neural network simulations. Plastic ENODes are also fabricated on flexible substrates enabling the integration of neuromorphic functionality in stretchable electronic systems. Mechanical flexibility makes ENODes compatible with three-dimensional architectures, opening a path towards extreme interconnectivity comparable to the human brain.

A non-volatile organic electrochemical device as a low-voltage artificial synapse for neuromorphic computing.

PubMed

van de Burgt, Yoeri; Lubberman, Ewout; Fuller, Elliot J; Keene, Scott T; Faria, Grégorio C; Agarwal, Sapan; Marinella, Matthew J; Alec Talin, A; Salleo, Alberto

2017-04-01

The brain is capable of massively parallel information processing while consuming only ∼1-100 fJ per synaptic event. Inspired by the efficiency of the brain, CMOS-based neural architectures and memristors are being developed for pattern recognition and machine learning. However, the volatility, design complexity and high supply voltages for CMOS architectures, and the stochastic and energy-costly switching of memristors complicate the path to achieve the interconnectivity, information density, and energy efficiency of the brain using either approach. Here we describe an electrochemical neuromorphic organic device (ENODe) operating with a fundamentally different mechanism from existing memristors. ENODe switches at low voltage and energy (<10 pJ for 10 3  μm 2 devices), displays >500 distinct, non-volatile conductance states within a ∼1 V range, and achieves high classification accuracy when implemented in neural network simulations. Plastic ENODes are also fabricated on flexible substrates enabling the integration of neuromorphic functionality in stretchable electronic systems. Mechanical flexibility makes ENODes compatible with three-dimensional architectures, opening a path towards extreme interconnectivity comparable to the human brain.

GaN-on-silicon high-electron-mobility transistor technology with ultra-low leakage up to 3000 V using local substrate removal and AlN ultra-wide bandgap

NASA Astrophysics Data System (ADS)

Dogmus, Ezgi; Zegaoui, Malek; Medjdoub, Farid

2018-03-01

We report on extremely low off-state leakage current in AlGaN/GaN-on-silicon metal–insulator–semiconductor high-electron-mobility transistors (MISHEMTs) up to a high blocking voltage. Remarkably low off-state gate and drain leakage currents below 1 µA/mm up to 3 kV have been achieved owing to the use of a thick in situ SiN gate dielectric under the gate, and a local Si substrate removal technique combined with a cost effective 15-µm-thick AlN dielectric layer followed by a Cu deposition. This result establishes a manufacturable state-of-the-art high-voltage GaN-on-silicon power transistors while maintaining a low specific on-resistance of approximately 10 mΩ·cm2.

Low-pressure hydrocracking of coal-derived Fischer-Tropsch waxes to diesel

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

Dieter Leckel

2007-06-15

Coal-derived low-temperature Fischer-Tropsch (LTFT) wax was hydrocracked at pressures of 3.5-7.0 MPa using silica-alumina-supported sulfided NiW/NiMo and an unsulfided noble metal catalyst, modified with MoO{sub 3}. A low-pressure operation at 3.5 MPa produced a highly isomerized diesel, having low cloud points (from -12 to -28{sup o}C) combined with high cetane numbers (69-73). These properties together with the extremely low sulfur ({lt}5 ppm) and aromatic ({lt}0.5%) contents place coal/liquid (CTL) derived distillates as highly valuable blending components to achieve Eurograde diesel specifications. The upgrading of coal-based LTFT waxes through hydrocracking to high-quality diesel fuel blend components in combination with commercial-feasible coal-integratedmore » gasification combined cycle (coal-IGCC) CO{sub 2} capture and storage schemes should make CTL technology more attractive. 28 refs., 7 figs., 8 tabs.« less

The promise and challenge of high-throughput sequencing of the antibody repertoire

PubMed Central

Georgiou, George; Ippolito, Gregory C; Beausang, John; Busse, Christian E; Wardemann, Hedda; Quake, Stephen R

2014-01-01

Efforts to determine the antibody repertoire encoded by B cells in the blood or lymphoid organs using high-throughput DNA sequencing technologies have been advancing at an extremely rapid pace and are transforming our understanding of humoral immune responses. Information gained from high-throughput DNA sequencing of immunoglobulin genes (Ig-seq) can be applied to detect B-cell malignancies with high sensitivity, to discover antibodies specific for antigens of interest, to guide vaccine development and to understand autoimmunity. Rapid progress in the development of experimental protocols and informatics analysis tools is helping to reduce sequencing artifacts, to achieve more precise quantification of clonal diversity and to extract the most pertinent biological information. That said, broader application of Ig-seq, especially in clinical settings, will require the development of a standardized experimental design framework that will enable the sharing and meta-analysis of sequencing data generated by different laboratories. PMID:24441474

A two-stage enzymatic process for synthesis of extremely pure high oleic glycerol monooleate.

PubMed

Zhu, Qisi; Li, Tie; Wang, Yonghua; Yang, Bo; Ma, Yongjun

2011-02-08

This paper presents a research interest concentrating on aims to establish a feasible industrial process for enzymatic production of highly pure glycerol monooleate (GMO). The synthesis of high oleic glycerol monooleate by enzymatic glycerolysis of high oleic sunflower oil, using Novozyme 435 as the biocatalyst, in a binary solvent mixture of tert-butanol and tert-pentanol (80/20, v/v), at a lab scale has been studied. A yield of 75.31% monoacylglycerol has been achieved at the first stage. A yield of 93.3% GMO was finally reached after further purification at the second stage. To evaluate the possibility of the process for industrialization, production of GMO was performed at a pilot-plant scale under the correspondingly adjusted conditions. A yield of 68.17% and 93.4% of GMO was obtained, respectively, at the end of the three stages. Copyright © 2010 Elsevier Inc. All rights reserved.

High average power, highly brilliant laser-produced plasma source for soft X-ray spectroscopy.

PubMed

Mantouvalou, Ioanna; Witte, Katharina; Grötzsch, Daniel; Neitzel, Michael; Günther, Sabrina; Baumann, Jonas; Jung, Robert; Stiel, Holger; Kanngiesser, Birgit; Sandner, Wolfgang

2015-03-01

In this work, a novel laser-produced plasma source is presented which delivers pulsed broadband soft X-radiation in the range between 100 and 1200 eV. The source was designed in view of long operating hours, high stability, and cost effectiveness. It relies on a rotating and translating metal target and achieves high stability through an on-line monitoring device using a four quadrant extreme ultraviolet diode in a pinhole camera arrangement. The source can be operated with three different laser pulse durations and various target materials and is equipped with two beamlines for simultaneous experiments. Characterization measurements are presented with special emphasis on the source position and emission stability of the source. As a first application, a near edge X-ray absorption fine structure measurement on a thin polyimide foil shows the potential of the source for soft X-ray spectroscopy.

National Aerospace Plane Engine Seals: High Temperature Seal Performance Evaluation

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.

1991-01-01

The key to the successful development of the single stage to orbit National Aerospace Plane (NASP) is the successful development of combined cycle ramjet/scramjet engines that can propel the vehicle to 17,000 mph to reach low Earth orbit. To achieve engine performance over this speed range, movable engine panels are used to tailor engine flow that require low leakage, high temperature seals around their perimeter. NASA-Lewis is developing a family of new high temperature seals to form effective barriers against leakage of extremely hot (greater than 2000 F), high pressure (up to 100 psi) flow path gases containing hydrogen and oxygen. Preventing backside leakage of these explosive gas mixtures is paramount in preventing the potential loss of the engine or the entire vehicle. Seal technology development accomplishments are described in the three main areas of concept development, test, and evaluation and analytical development.

Environmental applications of single collector high resolution ICP-MS.

PubMed

Krachler, Michael

2007-08-01

The number of environmental applications of single collector high resolution ICP-MS (HR-ICP-MS) has increased rapidly in recent years. There are many factors that contribute to make HR-ICP-MS a very powerful tool in environmental analysis. They include the extremely low detection limits achievable, tremendously high sensitivity, the ability to separate ICP-MS signals of the analyte from spectral interferences, enabling the reliable determination of many trace elements, and the reasonable precision of isotope ratio measurements. These assets are improved even further using high efficiency sample introduction systems. Therefore, external factors such as the stability of laboratory blanks are frequently the limiting factor in HR-ICP-MS analysis rather than the detection power. This review aims to highlight the most recent applications of HR-ICP-MS in this sector, focusing on matrices and applications where the superior capabilities of the instrumental technique are most useful and often ultimately required.

EUV spectroscopy of highly charged high Z ions in the Large Helical Device plasmas

NASA Astrophysics Data System (ADS)

Suzuki, C.; Koike, F.; Murakami, I.; Tamura, N.; Sudo, S.; Sakaue, H. A.; Nakamura, N.; Morita, S.; Goto, M.; Kato, D.; Nakano, T.; Higashiguchi, T.; Harte, C. S.; OʼSullivan, G.

2014-11-01

We present recent results on the extreme ultraviolet (EUV) spectroscopy of highly charged high Z ions in plasmas produced in the Large Helical Device (LHD) at the National Institute for Fusion Science. Tungsten, bismuth and lanthanide elements have recently been studied in the LHD in terms of their importance in fusion research and EUV light source development. In relatively low temperature plasmas, quasicontinuum emissions from open 4d or 4f subshell ions are predominant in the EUV region, while the spectra tend to be dominated by discrete lines from open 4s or 4p subshell ions in higher temperature plasmas. Comparative analyses using theoretical calculations and charge-separated spectra observed in an electron beam ion trap have been performed to achieve better agreement with the spectra measured in the LHD. As a result, databases on Z dependence of EUV spectra in plasmas have been widely extended.

Multiscale Simulations of ALD in Cross Flow Reactors

DOE PAGES

Yanguas-Gil, Angel; Libera, Joseph A.; Elam, Jeffrey W.

2014-08-13

In this study, we have developed a multiscale simulation code that allows us to study the impact of surface chemistry on the coating of large area substrates with high surface area/high aspect-ratio features. Our code, based on open-source libraries, takes advantage of the ALD surface chemistry to achieve an extremely efficient two-way coupling between reactor and feature length scales, and it can provide simulated quartz crystal microbalance and mass spectrometry data at any point of the reactor. By combining experimental surface characterization with simple analysis of growth profiles in a tubular cross flow reactor, we are able to extract amore » minimal set of reactions to effectively model the surface chemistry, including the presence of spurious CVD, to evaluate the impact of surface chemistry on the coating of large, high surface area substrates.« less

Alkaline batteries for hybrid and electric vehicles

NASA Astrophysics Data System (ADS)

Haschka, F.; Warthmann, W.; Benczúr-Ürmössy, G.

Forced by the USABC PNGV Program and the EZEV regulation in California, the development of hybrid vehicles become more strong. Hybrids offer flexible and unrestricted mobility, as well as pollution-free driving mode in the city. To achieve these requirements, high-power storage systems are demanded fulfilled by alkaline batteries (e.g., nickel/cadmium, nickel/metal hydride). DAUG has developed nickel/cadmium- and nickel/metal hydride cells in Fibre Technology of different performance types (up to 700 W/kg peak power) and proved in electric vehicles of different projects. A special bipolar cell design will meet even extreme high power requirements with more than 1000 W/kg peak power. The cells make use of the Recom design ensuring high power charge ability at low internal gas pressure. The paper presents laboratory test results of cells and batteries.

Anticancer drug-based multifunctional nanogels through self-assembly of dextran-curcumin conjugates toward cancer theranostics.

PubMed

Nagahama, Koji; Sano, Yoshinori; Kumano, Takayuki

2015-06-15

Curcumin (CCM) has been received much attention in cancer theranostics because CCM exhibits both anticancer activity and strong fluorescence available for bio-imaging. However, CCM has never been utilized in clinical mainly due to its extremely low water solubility and its low cellular uptake into cancer cells. We fabricated novel CCM-based biodegradable nanoparticles through self-assembly of amphiphilic dextran-CCM conjugates. Significantly high CCM loading contents in the nanoparticles and the high water solubility were achieved. Importantly, the dextran-CCMs nanoparticles were effectively delivered into HeLa cells and exhibited strong fluorescence available for live-cell imaging, although the nanoparticles were not delivered into normal cells. Thus, the dextran-CCMs nanoparticles could be a promising for creation of novel CCM-based cancer theranostics with high efficacy. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cognitive Profiles of Mathematical Problem Solving Learning Disability for Different Definitions of Disability

PubMed Central

Tolar, Tammy D.; Fuchs, Lynn; Fletcher, Jack M.; Fuchs, Douglas; Hamlett, Carol L.

2014-01-01

Three cohorts of third-grade students (N = 813) were evaluated on achievement, cognitive abilities, and behavioral attention according to contrasting research traditions in defining math learning disability (LD) status: low achievement versus extremely low achievement and IQ-achievement discrepant versus strictly low-achieving LD. We use methods from these two traditions to form math problem solving LD groups. To evaluate group differences, we used MANOVA-based profile and canonical analyses to control for relations among the outcomes and regression to control for group definition variables. Results suggest that basic arithmetic is the key distinguishing characteristic that separates low-achieving problem solvers (including LD, regardless of definition) from typically achieving students. Word problem solving is the key distinguishing characteristic that separates IQ-achievement-discrepant from strictly low-achieving LD students, favoring the IQ-achievement-discrepant students. PMID:24939971

ZnCr2S4: Highly effective photocatalyst converting nitrate into N2 without over-reduction under both UV and pure visible light

NASA Astrophysics Data System (ADS)

Yue, Mufei; Wang, Rong; Cheng, Nana; Cong, Rihong; Gao, Wenliang; Yang, Tao

2016-08-01

We propose several superiorities of applying some particular metal sulfides to the photocatalytic nitrate reduction in aqueous solution, including the high density of photogenerated excitons, high N2 selectivity (without over-reduction to ammonia). Indeed, ZnCr2S4 behaved as a highly efficient photocatalyst, and with the assistance of 1 wt% cocatalysts (RuOx, Ag, Au, Pd, or Pt), the efficiency was greatly improved. The simultaneous loading of Pt and Pd led to a synergistic effect. It offered the highest nitrate conversion rate of ~45 mg N/h together with the N2 selectivity of ~89%. Such a high activity remained steady after 5 cycles. The optimal apparent quantum yield at 380 nm was 15.46%. More importantly, with the assistance of the surface plasma resonance effect of Au, the visible light activity achieved 1.352 mg N/h under full arc Xe-lamp, and 0.452 mg N/h under pure visible light (λ > 400 nm). Comparing to the previous achievements in photocatalytic nitrate removal, our work on ZnCr2S4 eliminates the over-reduction problem, and possesses an extremely high and steady activity under UV-light, as well as a decent conversion rate under pure visible light.

ZnCr2S4: Highly effective photocatalyst converting nitrate into N2 without over-reduction under both UV and pure visible light.

PubMed

Yue, Mufei; Wang, Rong; Cheng, Nana; Cong, Rihong; Gao, Wenliang; Yang, Tao

2016-08-03

We propose several superiorities of applying some particular metal sulfides to the photocatalytic nitrate reduction in aqueous solution, including the high density of photogenerated excitons, high N2 selectivity (without over-reduction to ammonia). Indeed, ZnCr2S4 behaved as a highly efficient photocatalyst, and with the assistance of 1 wt% cocatalysts (RuOx, Ag, Au, Pd, or Pt), the efficiency was greatly improved. The simultaneous loading of Pt and Pd led to a synergistic effect. It offered the highest nitrate conversion rate of ~45 mg N/h together with the N2 selectivity of ~89%. Such a high activity remained steady after 5 cycles. The optimal apparent quantum yield at 380 nm was 15.46%. More importantly, with the assistance of the surface plasma resonance effect of Au, the visible light activity achieved 1.352 mg N/h under full arc Xe-lamp, and 0.452 mg N/h under pure visible light (λ > 400 nm). Comparing to the previous achievements in photocatalytic nitrate removal, our work on ZnCr2S4 eliminates the over-reduction problem, and possesses an extremely high and steady activity under UV-light, as well as a decent conversion rate under pure visible light.

Towards coherent combining of X-band high power microwaves: phase-locked long pulse radiations by a relativistic triaxial klystron amplifier

PubMed Central

Ju, Jinchuan; Zhang, Jun; Qi, Zumin; Yang, Jianhua; Shu, Ting; Zhang, Jiande; Zhong, Huihuang

2016-01-01

The radio-frequency breakdown due to ultrahigh electric field strength essentially limits power handling capability of an individual high power microwave (HPM) generator, and this issue becomes more challenging for high frequency bands. Coherent power combining therefore provides an alternative approach to achieve an equivalent peak power of the order of ∼100 GW, which consequently provides opportunities to explore microwave related physics at extremes. The triaxial klystron amplifier (TKA) is a promising candidate for coherent power combing in high frequency bands owing to its intrinsic merit of high power capacity, nevertheless phase-locked long pulse radiation from TKA has not yet been obtained experimentally as the coaxial structure of TKA can easily lead to self-excitation of parasitic modes. In this paper, we present investigations into an X-band TKA capable of producing 1.1 GW HPMs with pulse duration of about 103 ns at the frequency of 9.375 GHz in experiment. Furthermore, the shot-to-shot fluctuation standard deviation of the phase shifts between the input and output microwaves is demonstrated to be less than 10°. The reported achievements open up prospects for accomplishing coherent power combining of X-band HPMs in the near future, and might also excite new development interests concerning high frequency TKAs. PMID:27481661

Towards coherent combining of X-band high power microwaves: phase-locked long pulse radiations by a relativistic triaxial klystron amplifier.

PubMed

Ju, Jinchuan; Zhang, Jun; Qi, Zumin; Yang, Jianhua; Shu, Ting; Zhang, Jiande; Zhong, Huihuang

2016-08-02

The radio-frequency breakdown due to ultrahigh electric field strength essentially limits power handling capability of an individual high power microwave (HPM) generator, and this issue becomes more challenging for high frequency bands. Coherent power combining therefore provides an alternative approach to achieve an equivalent peak power of the order of ∼100 GW, which consequently provides opportunities to explore microwave related physics at extremes. The triaxial klystron amplifier (TKA) is a promising candidate for coherent power combing in high frequency bands owing to its intrinsic merit of high power capacity, nevertheless phase-locked long pulse radiation from TKA has not yet been obtained experimentally as the coaxial structure of TKA can easily lead to self-excitation of parasitic modes. In this paper, we present investigations into an X-band TKA capable of producing 1.1 GW HPMs with pulse duration of about 103 ns at the frequency of 9.375 GHz in experiment. Furthermore, the shot-to-shot fluctuation standard deviation of the phase shifts between the input and output microwaves is demonstrated to be less than 10°. The reported achievements open up prospects for accomplishing coherent power combining of X-band HPMs in the near future, and might also excite new development interests concerning high frequency TKAs.

Association of extremely high levels of high-density lipoprotein cholesterol with cardiovascular mortality in a pooled analysis of 9 cohort studies including 43,407 individuals: The EPOCH-JAPAN study.

PubMed

Hirata, Aya; Sugiyama, Daisuke; Watanabe, Makoto; Tamakoshi, Akiko; Iso, Hiroyasu; Kotani, Kazuhiko; Kiyama, Masahiko; Yamada, Michiko; Ishikawa, Shizukiyo; Murakami, Yoshitaka; Miura, Katsuyuki; Ueshima, Hirotsugu; Okamura, Tomonori

2018-02-08

The effect of very high or extremely high levels of high-density lipoprotein cholesterol (HDL-C) on cardiovascular disease (CVD) is not well described. Although a few recent studies have reported the adverse effects of extremely high levels of HDL-C on CVD events, these did not show a statistically significant association between extremely high levels of HDL-C and cause-specific CVD mortality. In addition, Asian populations have not been studied. We examine the impact of extremely high levels of HDL-C on cause-specific CVD mortality using pooled data of Japanese cohort studies. We performed a large-scale pooled analysis of 9 Japanese cohorts including 43,407 participants aged 40-89 years, dividing the participants into 5 groups by HDL-C levels, including extremely high levels of HDL-C ≥2.33 mmol/L (≥90 mg/dL). We estimated the adjusted hazard ratio of each HDL-C category for all-cause death and cause-specific deaths compared with HDL-C 1.04-1.55 mmol/L (40-59 mg/dL) using a cohort-stratified Cox proportional hazards model. During a 12.1-year follow-up, 4995 all-cause deaths and 1280 deaths due to overall CVD were identified. Extremely high levels of HDL-C were significantly associated with increased risk of atherosclerotic CVD mortality (hazard ratio = 2.37, 95% confidence interval: 1.37-4.09 for total) and increased risk for coronary heart disease and ischemic stroke. In addition, the risk for extremely high HDL-C was more evident among current drinkers. We showed extremely high levels of HDL-C had an adverse effect on atherosclerotic CVD mortality in a pooled analysis of Japanese cohorts. Copyright © 2018 National Lipid Association. Published by Elsevier Inc. All rights reserved.

The use of lasers for achieving extreme conditions of matter, and fusion

NASA Astrophysics Data System (ADS)

Roberts, P. D.

2012-05-01

Since the early'70s AWE has focussed on indirect drive as a means of accessing high energy density regimes. We give a brief historical perspective of this work and the rationale for the construction of the ORION laser. This laser is currently in commissioning and is scheduled to commence experiments in 2012. The ORION laser is configured to provide long pulses (~ 1ns) with a high degree of pulse shape flexibility, together with synchronised short pulse (~1ps) irradiation. The paper describes how this combination should enable pressures in excess of 1 Gb and temperatures of greater than 500 eV to be achieved. The ability to access and diagnose such conditions has applications in many fields; examples are given in planetary science, astrophysics and inertial fusion energy. For these applications we first describe the approach to measuring equation of state and opacity properties in the high energy density regime. Such properties are then incorporated into integrated computer simulation codes and validated against laser experiments, some of which have been conducted recently at the OMEGA laser at the University of Rochester. The paper concludes with a discussion of inertial fusion energy and the new high energy density regimes that this would access, if successful.

Future changes in precipitation patterns and extremes: a model-based approach

NASA Astrophysics Data System (ADS)

Mitsakis, Evangelos; Stamos, Iraklis; Anastassiadou, Kalliopi; Kammerer, Harald; Kaundinya, Ingo; Kohl, Bernhard; Kapsomenakis, John; Zerefos, Christos; Aifadopoulou, Georfia

2016-04-01

In recent decades, the Earth has experienced abrupt climate changes, including changes of mean precipitation heights as well as precipitation extremes. It is very likely that the abrupt climate changes which are result of the increase of the greenhouse gases (GHG) concentration (IPCC 2007) will continue with an accelerate magnitude in the coming decades. The modern tool used to project the future climate change is General Circulation Models (GCMs). Due to computational resources limitations, the horizontal resolution of present day GCMs is quite low, usually in the order of hundreds of kilometers. In such a crude resolution many local aspects of the climate are unable to be represented. In addition, the topographical input is equally crude, thus excluding important local features of the topographic forcing. For these reasons downscaling methods have been developed, which input the GCM results producing high resolution localized climate information. Dynamical downscaling is achieved using Regional Climate Models (RCMs) that increase the resolution of the GCMs to even less than 10 km. In that direction, future changes in the mean precipitation as well as precipitation extremes due to the anthropogenic climate change over the area of Greece are examined for various emission scenarios in the framework of this paper (e.g. RCP 8.5, SRES A1B, etc.). Regarding Greece, future changes are based on daily precipitation data from 18 Region Climate Models simulations (6 for RCP 8.5 and 12 for SRES A1B). The changes in precipitation extremes are defined by calculating the changes of nine extreme precipitation indices which are divided in three categories: percentile (R75p, R95p, R99p), absolute threshold (Rmax, R10, R20, R50, RX5day) and duration (CDD) indices, as defined by the Expert Team on Climate Change Detection and Indices (ETCCDI). Taking into account all the results that are discussed explicitly in the following sections we conclude that the mean precipitation as well as the number of moderate rainy days is projected to decrease over Greece especially in the end of 21th century. Nevertheless the frequency as well as the strength of individual extremely high precipitation events will be increased over the largest part of Greece.

Single-Walled Carbon Nanotube Film Supported Nanofiltration Membrane with a Nearly 10 nm Thick Polyamide Selective Layer for High-Flux and High-Rejection Desalination.

PubMed

Zhu, Yuzhang; Xie, Wei; Gao, Shoujian; Zhang, Feng; Zhang, Wenbin; Liu, Zhaoyang; Jin, Jian

2016-09-01

Fabricating nanofiltration (NF) membranes with high permeating flux and simultaneous high rejection rate for desalination is rather significant and highly desired. A new avenue is reported in this work to design NF membrane by using polydopamine wrapped single-walled carbon nanotube (PD/SWCNTs) ultrathin film as support layer instead of the use of traditional polymer-based underlying layers. Thanks to the high porosity, smooth surface, and more importantly optimal hydrophilic surface of PD/SWCNTs film, a defect-free polyamide selective layer for NF membrane with thickness of as thin as 12 nm is achieved. The obtained NF membrane exhibits an extremely high performance with a permeating flux of 32 L m -2 h -1 bar -1 and a rejection rate of 95.9% to divalent ions. This value is two to five times higher than the traditional NF membranes with similar rejection rate. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly stable, extremely high-temperature, nonvolatile memory based on resistance switching in polycrystalline Pt nanogaps

PubMed Central

Suga, Hiroshi; Suzuki, Hiroya; Shinomura, Yuma; Kashiwabara, Shota; Tsukagoshi, Kazuhito; Shimizu, Tetsuo; Naitoh, Yasuhisa

2016-01-01

Highly stable, nonvolatile, high-temperature memory based on resistance switching was realized using a polycrystalline platinum (Pt) nanogap. The operating temperature of the memory can be drastically increased by the presence of a sharp-edged Pt crystal facet in the nanogap. A short distance between the facet edges maintains the nanogap shape at high temperature, and the sharp shape of the nanogap densifies the electric field to maintain a stable current flow due to field migration. Even at 873 K, which is a significantly higher temperature than feasible for conventional semiconductor memory, the nonvolatility of the proposed memory allows stable ON and OFF currents, with fluctuations of less than or equal to 10%, to be maintained for longer than eight hours. An advantage of this nanogap scheme for high-temperature memory is its secure operation achieved through the assembly and disassembly of a Pt needle in a high electric field. PMID:27725705

Extreme sub-threshold swing in tunnelling relays

NASA Astrophysics Data System (ADS)

AbdelGhany, M.; Szkopek, T.

2014-01-01

We propose and analyze the theory of the tunnelling relay, a nanoscale active device in which tunnelling current is modulated by electromechanical actuation of a suspended membrane above a fixed electrode. The tunnelling current is modulated exponentially with vacuum gap length, permitting an extreme sub-threshold swing of ˜10 mV/decade breaking the thermionic limit. The predicted performance suggests that a significant reduction in dynamic energy consumption over conventional field effect transistors is physically achievable.

Present status and future prospect of coated conductor development and its application in Japan

NASA Astrophysics Data System (ADS)

Shiohara, Y.; Yoshizumi, M.; Izumi, T.; Yamada, Y.

2008-03-01

The current national project on coated conductors using Y-system superconductors has been carried out over the project period (FY2003-FY2007). In this paper, the current status and the future prospect of this project are reviewed. The high performance tape development group, consisting of Fujikura and SRL-NCCC, has worked on the tape by PLD-REBCO superconducting layers on PLD-CeO2/IBAD-GZO buffered substrates. A high product of Ic and L, higher than 112 166 A m, was achieved in a 368 m-304.8 A GdBCO tape whose Ic value is mostly above 350 A/cm in width. The performance under magnetic field was also improved up to 42 A at 3 T in a GdBCO short film with doping of ZrO2. 61 m long GdBCO tape with ZrO2 doping showed a high Ic value of 220 A at self field and 30 A at 3 T. On the other hand, another group focusing on low production cost has worked on TFA-MOD and MOCVD processes. The extremely high Ic value of 735 A/cm-w was obtained in TFA-MOD films on PLD-CeO2/IBAD-GZO/Hastelloy substrate due to the effect of Ba-poor nominal composition. In efforts towards long tape production by the SWCC group, a 200 m long tape with a high Ic value of 200 A/cm-w was obtained using a batch-type furnace. The Ic × L value of this tape was 40 000 A m, which is the highest value in the world obtained by the TFA-MOD process. Based on the above achievements in coated conductor process development, two new additional goals were set in the project. One is the development of extremely low cost tape and the other is the development of the basic technologies for making electric power devices of cables, transformers, motors, current-limiters and cryocoolers. Some of the new investigations have already revealed marvellous results, such as a 15 kW motor, low AC loss coils, low AC loss cables, etc.

Application of RFID technology-upper extremity rehabilitation training.

PubMed

Chen, Chih-Chen; Chen, Yu-Luen; Chen, Shih-Ching

2016-01-01

[Purpose] Upper extremity rehabilitation after an injury is very important. This study proposes radio frequency identification (RFID) technology to improve and enhance the effectiveness of the upper extremity rehabilitation. [Subjects and Methods] People use their upper extremities to conduct daily activities. When recovering from injuries, many patients neglect the importance of rehabilitation, which results in degraded function. This study recorded the training process using the traditional rehabilitation hand gliding cart with a RFID reader, RFID tags in the panel, and a servo host computer. [Results] Clinical evidence, time taken to achieve a full score, counts of missing the specified spots, and Brunnstrom stage of aided recovery, the proximal part of the upper extremity show that the RFID-based upper extremity training significantly and reduce negative impacts of the disability in daily life and activities. [Conclusion] This study combined a hand-gliding cart with an RFID reader, and when patients moved the cart, the movement could be observed via the activated RFID tags. The training data was collected and quantified for a better understanding of the recovery status of the patients. Each of the participating patients made progress as expected.

Current status and future prospects of Japanese national project on coated conductor development and its applications

NASA Astrophysics Data System (ADS)

Shiohara, Y.; Yoshizumi, M.; Izumi, T.; Yamada, Y.

2008-09-01

Four years of the current five-year national project since 2003 for development of coated conductors using Y-system superconductors have passed and lots of remarkable results have been achieved. In this paper, the current status and the future prospect of this project are reviewed. The current national project comprises several groups of national laboratories, universities and private companies. The group of high performance tape development, consisting of Fujikura and SRL-NCCC, has worked on the tape by PLD-REBCO superconducting tapes on the PLD-CeO 2/IBAD-GZO buffered substrates. The high product of Ic and L equal to 112,166 A m was achieved in the 368 m-304.8 A GdBCO tape whose Ic value is mostly above 350 A/cm-w. The performance under the magnetic fields was also improved up to 42 A at 3 T in a GdBCO short film with doping of ZrO 2. About 61 m long GdBCO tape with ZrO 2 doping showed a high Ic value of 220 A at self field and 30 A at 3 T. On the other hand, the other group focusing on the low production cost has worked on processes of TFA-MOD and MOCVD, etc. The extremely high Ic value of 735 A/cm-w was attained in the TFA-MOD films on PLD-CeO 2/IBAD-GZO/Hastelloy C276 substrate by means of using the effect of Ba-poor nominal composition. In the efforts for long tape production, 200 m long tapes with high Ic values of 200 A/cm-w and 205 A/cm-w were obtained by MOD-YBCO/PLD-CeO 2/IBAD-GZO/Hastelloy C276 and PLD-HoBCO on buffered NiW substrate, respectively. The Ic × L value of the MOD-derived tape was 40,000 A m, which is the highest value in the world by the MOD process. Based on the above achievements on the coated conductor process development, two new additional goals were set in the project. One is the development for the extremely low cost tape and another is the development of the basic technologies for making the electric power devices including cables, transformers, motors, current-limiters and cryocoolers. Some of the new themes already revealed the marvellous results such as 15 kW motor, low AC loss coils, low AC loss cables, etc.

Can pair-instability supernova models match the observations of superluminous supernovae?

NASA Astrophysics Data System (ADS)

Kozyreva, Alexandra; Blinnikov, S.

2015-12-01

An increasing number of so-called superluminous supernovae (SLSNe) are discovered. It is believed that at least some of them with slowly fading light curves originate in stellar explosions induced by the pair instability mechanism. Recent stellar evolution models naturally predict pair instability supernovae (PISNe) from very massive stars at wide range of metallicities (up to Z = 0.006, Yusof et al.). In the scope of this study, we analyse whether PISN models can match the observational properties of SLSNe with various light-curve shapes. Specifically, we explore the influence of different degrees of macroscopic chemical mixing in PISN explosive products on the resulting observational properties. We artificially apply mixing to the 250 M⊙ PISN evolutionary model from Kozyreva et al. and explore its supernova evolution with the one-dimensional radiation hydrodynamics code STELLA. The greatest success in matching SLSN observations is achieved in the case of an extreme macroscopic mixing, where all radioactive material is ejected into the hydrogen-helium outer layer. Such an extreme macroscopic redistribution of chemicals produces events with faster light curves with high photospheric temperatures and high photospheric velocities. These properties fit a wider range of SLSNe than non-mixed PISN model. Our mixed models match the light curves, colour temperature, and photospheric velocity evolution of two well-observed SLSNe PTF12dam and LSQ12dlf. However, these models' extreme chemical redistribution may be hard to realize in massive PISNe. Therefore, alternative models such as the magnetar mechanism or wind-interaction may still to be favourable to interpret rapidly rising SLSNe.

Modeling Spatial Dependence of Rainfall Extremes Across Multiple Durations

NASA Astrophysics Data System (ADS)

Le, Phuong Dong; Leonard, Michael; Westra, Seth

2018-03-01

Determining the probability of a flood event in a catchment given that another flood has occurred in a nearby catchment is useful in the design of infrastructure such as road networks that have multiple river crossings. These conditional flood probabilities can be estimated by calculating conditional probabilities of extreme rainfall and then transforming rainfall to runoff through a hydrologic model. Each catchment's hydrological response times are unlikely to be the same, so in order to estimate these conditional probabilities one must consider the dependence of extreme rainfall both across space and across critical storm durations. To represent these types of dependence, this study proposes a new approach for combining extreme rainfall across different durations within a spatial extreme value model using max-stable process theory. This is achieved in a stepwise manner. The first step defines a set of common parameters for the marginal distributions across multiple durations. The parameters are then spatially interpolated to develop a spatial field. Storm-level dependence is represented through the max-stable process for rainfall extremes across different durations. The dependence model shows a reasonable fit between the observed pairwise extremal coefficients and the theoretical pairwise extremal coefficient function across all durations. The study demonstrates how the approach can be applied to develop conditional maps of the return period and return level across different durations.

Preservation of REE and Fe isotopes in altered stromatolites and the paleo-environmental record

NASA Astrophysics Data System (ADS)

Nies, S. M.; Shapiro, R. S.; Lalonde, S.

2015-12-01

Geochemical proxies are increasingly being used to unravel ancient ecosystems and environmental perturbations back to the earliest rock record on Earth. Along with more traditional fossils (stromatolites) and other biosignatures (e.g., lipids), the geochemical record is used specifically to evaluate biogenecity and to understand oxygenation of the atmosphere and ocean in the Archean and Paleoproterozoic. However, the effects of diagenesis, metamorphism, and other modes of secondary alteration are still poorly constrained, particularly as technological advances allow us to expand farther across the periodic table. Our study focused on the robustness and preservation of rare earth element (REE) and Fe isotope compositions of two stromatolitic units that have undergone contact and regional metamorphism. 18 samples were collected from cores, open pit mines, and field locations in Minnesota and Ontario from silicified iron formation (Biwabik-Gunflint formations). The samples were carefully constrained to one of two meter-scale stromatolitic units. Metamorphic grade ranged from essentially unmetamorphosed through prehnite-pumpellyite up to amphibolite (fayalite+hypersthene). Samples were also collected that represented deep secondary weathering, likely related to Cretaceous climatic extremes. Polished samples were first analyzed by electron microprobe and selected samples were further analyzed via laser ablation HR-ICP-MS to constrain trace element (n=13) and Fe isotopic variations (n=8). Preliminary results indicate that transition metal concentrations are surprisingly resilient to high-temperature metamorphic recrystallization. REE concentrations were analyzed in individual iron oxide grains, with full resolution (La to Lu) achieved for some samples and partial resolution (La to Nd) achieved for all samples. Core samples exhibited a relatively stable positive Ce anomaly occurring from low to extremely high alteration. Outcrop and mine samples indicate a shift from a negative Ce anomaly in less altered samples, to a positive Ce anomaly in highly altered samples. Collectively, our results imply that caution is warranted when making paleo-environmental inferences from samples with significantly different alteration histories.

Co-immobilization of multiple enzymes by metal coordinated nucleotide hydrogel nanofibers: improved stability and an enzyme cascade for glucose detection

NASA Astrophysics Data System (ADS)

Liang, Hao; Jiang, Shuhui; Yuan, Qipeng; Li, Guofeng; Wang, Feng; Zhang, Zijie; Liu, Juewen

2016-03-01

Preserving enzyme activity and promoting synergistic activity via co-localization of multiple enzymes are key topics in bionanotechnology, materials science, and analytical chemistry. This study reports a facile method for co-immobilizing multiple enzymes in metal coordinated hydrogel nanofibers. Specifically, four types of protein enzymes, including glucose oxidase, Candida rugosa lipase, α-amylase, and horseradish peroxidase, were respectively encapsulated in a gel nanofiber made of Zn2+ and adenosine monophosphate (AMP) with a simple mixing step. Most enzymes achieved quantitative loading and retained full activity. At the same time, the entrapped enzymes were more stable against temperature variation (by 7.5 °C), protease attack, extreme pH (by 2-fold), and organic solvents. After storing for 15 days, the entrapped enzyme still retained 70% activity while the free enzyme nearly completely lost its activity. Compared to nanoparticles formed with AMP and lanthanide ions, the nanofiber gels allowed much higher enzyme activity. Finally, a highly sensitive and selective biosensor for glucose was prepared using the gel nanofiber to co-immobilize glucose oxidase and horseradish peroxidase for an enzyme cascade system. A detection limit of 0.3 μM glucose with excellent selectivity was achieved. This work indicates that metal coordinated materials using nucleotides are highly useful for interfacing with biomolecules.Preserving enzyme activity and promoting synergistic activity via co-localization of multiple enzymes are key topics in bionanotechnology, materials science, and analytical chemistry. This study reports a facile method for co-immobilizing multiple enzymes in metal coordinated hydrogel nanofibers. Specifically, four types of protein enzymes, including glucose oxidase, Candida rugosa lipase, α-amylase, and horseradish peroxidase, were respectively encapsulated in a gel nanofiber made of Zn2+ and adenosine monophosphate (AMP) with a simple mixing step. Most enzymes achieved quantitative loading and retained full activity. At the same time, the entrapped enzymes were more stable against temperature variation (by 7.5 °C), protease attack, extreme pH (by 2-fold), and organic solvents. After storing for 15 days, the entrapped enzyme still retained 70% activity while the free enzyme nearly completely lost its activity. Compared to nanoparticles formed with AMP and lanthanide ions, the nanofiber gels allowed much higher enzyme activity. Finally, a highly sensitive and selective biosensor for glucose was prepared using the gel nanofiber to co-immobilize glucose oxidase and horseradish peroxidase for an enzyme cascade system. A detection limit of 0.3 μM glucose with excellent selectivity was achieved. This work indicates that metal coordinated materials using nucleotides are highly useful for interfacing with biomolecules. Electronic supplementary information (ESI) available: Additional methods, IR and XRD spectroscopy, enzyme loading capacity, enzyme kinetic parameters, and enzyme stability data. See DOI: 10.1039/c5nr08734a

In situ polymerized superhydrophobic and superoleophilic nanofibrous membranes for gravity driven oil-water separation

NASA Astrophysics Data System (ADS)

Tang, Xiaomin; Si, Yang; Ge, Jianlong; Ding, Bin; Liu, Lifang; Zheng, Gang; Luo, Wenjing; Yu, Jianyong

2013-11-01

Creating an efficient, cost-effective method that can provide simple, practical and high-throughput separation of oil-water mixtures has proved extremely challenging. This work responds to these challenges by designing, fabricating and evaluating a novel fluorinated polybenzoxazine (F-PBZ) modified nanofibrous membrane optimized to achieve gravity driven oil-water separation. The membrane design is then realized by a facile combination of electrospun poly(m-phenylene isophthalamide) (PMIA) nanofibers and an in situ polymerized F-PBZ functional layer incorporating SiO2 nanoparticles (SiO2 NPs). By employing the F-PBZ/SiO2 NP modification, the pristine hydrophilic PMIA nanofibrous membranes are endowed with promising superhydrophobicity with a water contact angle of 161° and superoleophilicity with an oil contact angle of 0°. This new membrane shows high thermal stability (350 °C) and good repellency to hot water (80 °C), and achieves an excellent mechanical strength of 40.8 MPa. Furthermore, the as-prepared membranes exhibited fast and efficient separation of oil-water mixtures by a solely gravity driven process, which makes them good candidates for industrial oil-polluted water treatments and oil spill cleanup, and also provided new insights into the design and development of functional nanofibrous membranes through F-PBZ modification.Creating an efficient, cost-effective method that can provide simple, practical and high-throughput separation of oil-water mixtures has proved extremely challenging. This work responds to these challenges by designing, fabricating and evaluating a novel fluorinated polybenzoxazine (F-PBZ) modified nanofibrous membrane optimized to achieve gravity driven oil-water separation. The membrane design is then realized by a facile combination of electrospun poly(m-phenylene isophthalamide) (PMIA) nanofibers and an in situ polymerized F-PBZ functional layer incorporating SiO2 nanoparticles (SiO2 NPs). By employing the F-PBZ/SiO2 NP modification, the pristine hydrophilic PMIA nanofibrous membranes are endowed with promising superhydrophobicity with a water contact angle of 161° and superoleophilicity with an oil contact angle of 0°. This new membrane shows high thermal stability (350 °C) and good repellency to hot water (80 °C), and achieves an excellent mechanical strength of 40.8 MPa. Furthermore, the as-prepared membranes exhibited fast and efficient separation of oil-water mixtures by a solely gravity driven process, which makes them good candidates for industrial oil-polluted water treatments and oil spill cleanup, and also provided new insights into the design and development of functional nanofibrous membranes through F-PBZ modification. Electronic supplementary information (ESI) available: Detailed synthesis and structural confirmation of BAF-oda, OCA results, Raman spectrum and Movies S1 and S2. See DOI: 10.1039/c3nr03937d

A Synoptic Weather Typing Approach and Its application to Assess Climate Change Impacts on Extreme Weather Events at Local Scale in South-Central Canada

NASA Astrophysics Data System (ADS)

Shouquan Cheng, Chad; Li, Qian; Li, Guilong

2010-05-01

The synoptic weather typing approach has become popular in evaluating the impacts of climate change on a variety of environmental problems. One of the reasons is its ability to categorize a complex set of meteorological variables as a coherent index, which can facilitate analyses of local climate change impacts. The weather typing method has been successfully applied in Environment Canada for several research projects to analyze climatic change impacts on a number of extreme weather events, such as freezing rain, heavy rainfall, high-/low-flow events, air pollution, and human health. These studies comprise of three major parts: (1) historical simulation modeling to verify the extreme weather events, (2) statistical downscaling to provide station-scale future hourly/daily climate data, and (3) projections of changes in frequency and intensity of future extreme weather events in this century. To achieve these goals, in addition to synoptic weather typing, the modeling conceptualizations in meteorology and hydrology and a number of linear/nonlinear regression techniques were applied. Furthermore, a formal model result verification process has been built into each of the three parts of the projects. The results of the verification, based on historical observations of the outcome variables predicted by the models, showed very good agreement. The modeled results from these projects found that the frequency and intensity of future extreme weather events are projected to significantly increase under a changing climate in this century. This talk will introduce these research projects and outline the modeling exercise and result verification process. The major findings on future projections from the studies will be summarized in the presentation as well. One of the major conclusions from the studies is that the procedures (including synoptic weather typing) used in the studies are useful for climate change impact analysis on future extreme weather events. The implication of the significant increases in frequency and intensity of future extreme weather events would be useful to be considered when revising engineering infrastructure design standards and developing adaptation strategies and policies.

The CHARIS High-Contrast Integral-Field Spectrograph

NASA Technical Reports Server (NTRS)

Groff, Tyler D.; Chilcote, Jeffrey; Brandt, Timothy; Kasdin, N. Jeremy; Galvin, Michael; Loomis, Craig; Rizzo, Maxime; Knapp, Gillian; Guyon, Olivier; Jovanovic, Nemanja;

Achieving Extreme Utilization of Excitons by an Efficient Sandwich-Type Emissive Layer Architecture for Reduced Efficiency Roll-Off and Improved Operational Stability in Organic Light-Emitting Diodes.

PubMed

Wu, Zhongbin; Sun, Ning; Zhu, Liping; Sun, Hengda; Wang, Jiaxiu; Yang, Dezhi; Qiao, Xianfeng; Chen, Jiangshan; Alshehri, Saad M; Ahamad, Tansir; Ma, Dongge

2016-02-10

It has been demonstrated that the efficiency roll-off is generally caused by the accumulation of excitons or charge carriers, which is intimately related to the emissive layer (EML) architecture in organic light-emitting diodes (OLEDs). In this article, an efficient sandwich-type EML structure with a mixed-host EML sandwiched between two single-host EMLs was designed to eliminate this accumulation, thus simultaneously achieving high efficiency, low efficiency roll-off and good operational stability in the resulting OLEDs. The devices show excellent electroluminescence performances, realizing a maximum external quantum efficiency (EQE) of 24.6% with a maximum power efficiency of 105.6 lm W(-1) and a maximum current efficiency of 93.5 cd A(-1). At the high brightness of 5,000 cd m(-2), they still remain as high as 23.3%, 71.1 lm W(-1), and 88.3 cd A(-1), respectively. And, the device lifetime is up to 2000 h at initial luminance of 1000 cd m(-2), which is significantly higher than that of compared devices with conventional EML structures. The improvement mechanism is systematically studied by the dependence of the exciton distribution in EML and the exciton quenching processes. It can be seen that the utilization of the efficient sandwich-type EML broadens the recombination zone width, thus greatly reducing the exciton quenching and increasing the probability of the exciton recombination. It is believed that the design concept provides a new avenue for us to achieve high-performance OLEDs.

Extreme Faint Flux Imaging with an EMCCD

NASA Astrophysics Data System (ADS)

Daigle, Olivier; Carignan, Claude; Gach, Jean-Luc; Guillaume, Christian; Lessard, Simon; Fortin, Charles-Anthony; Blais-Ouellette, Sébastien

2009-08-01

An EMCCD camera, designed from the ground up for extreme faint flux imaging, is presented. CCCP, the CCD Controller for Counting Photons, has been integrated with a CCD97 EMCCD from e2v technologies into a scientific camera at the Laboratoire d’Astrophysique Expérimentale (LAE), Université de Montréal. This new camera achieves subelectron readout noise and very low clock-induced charge (CIC) levels, which are mandatory for extreme faint flux imaging. It has been characterized in laboratory and used on the Observatoire du Mont Mégantic 1.6 m telescope. The performance of the camera is discussed and experimental data with the first scientific data are presented.

High thermal conductivity in soft elastomers with elongated liquid metal inclusions.

PubMed

Bartlett, Michael D; Kazem, Navid; Powell-Palm, Matthew J; Huang, Xiaonan; Sun, Wenhuan; Malen, Jonathan A; Majidi, Carmel

2017-02-28

Soft dielectric materials typically exhibit poor heat transfer properties due to the dynamics of phonon transport, which constrain thermal conductivity ( k ) to decrease monotonically with decreasing elastic modulus ( E ). This thermal-mechanical trade-off is limiting for wearable computing, soft robotics, and other emerging applications that require materials with both high thermal conductivity and low mechanical stiffness. Here, we overcome this constraint with an electrically insulating composite that exhibits an unprecedented combination of metal-like thermal conductivity, an elastic compliance similar to soft biological tissue (Young's modulus < 100 kPa), and the capability to undergo extreme deformations (>600% strain). By incorporating liquid metal (LM) microdroplets into a soft elastomer, we achieve a ∼25× increase in thermal conductivity (4.7 ± 0.2 W⋅m -1 ⋅K -1 ) over the base polymer (0.20 ± 0.01 W⋅m -1 ·K -1 ) under stress-free conditions and a ∼50× increase (9.8 ± 0.8 W⋅m -1 ·K -1 ) when strained. This exceptional combination of thermal and mechanical properties is enabled by a unique thermal-mechanical coupling that exploits the deformability of the LM inclusions to create thermally conductive pathways in situ. Moreover, these materials offer possibilities for passive heat exchange in stretchable electronics and bioinspired robotics, which we demonstrate through the rapid heat dissipation of an elastomer-mounted extreme high-power LED lamp and a swimming soft robot.

Dynamic fracture of tantalum under extreme tensile stress.

PubMed

Albertazzi, Bruno; Ozaki, Norimasa; Zhakhovsky, Vasily; Faenov, Anatoly; Habara, Hideaki; Harmand, Marion; Hartley, Nicholas; Ilnitsky, Denis; Inogamov, Nail; Inubushi, Yuichi; Ishikawa, Tetsuya; Katayama, Tetsuo; Koyama, Takahisa; Koenig, Michel; Krygier, Andrew; Matsuoka, Takeshi; Matsuyama, Satoshi; McBride, Emma; Migdal, Kirill Petrovich; Morard, Guillaume; Ohashi, Haruhiko; Okuchi, Takuo; Pikuz, Tatiana; Purevjav, Narangoo; Sakata, Osami; Sano, Yasuhisa; Sato, Tomoko; Sekine, Toshimori; Seto, Yusuke; Takahashi, Kenjiro; Tanaka, Kazuo; Tange, Yoshinori; Togashi, Tadashi; Tono, Kensuke; Umeda, Yuhei; Vinci, Tommaso; Yabashi, Makina; Yabuuchi, Toshinori; Yamauchi, Kazuto; Yumoto, Hirokatsu; Kodama, Ryosuke

2017-06-01

The understanding of fracture phenomena of a material at extremely high strain rates is a key issue for a wide variety of scientific research ranging from applied science and technological developments to fundamental science such as laser-matter interaction and geology. Despite its interest, its study relies on a fine multiscale description, in between the atomic scale and macroscopic processes, so far only achievable by large-scale atomic simulations. Direct ultrafast real-time monitoring of dynamic fracture (spallation) at the atomic lattice scale with picosecond time resolution was beyond the reach of experimental techniques. We show that the coupling between a high-power optical laser pump pulse and a femtosecond x-ray probe pulse generated by an x-ray free electron laser allows detection of the lattice dynamics in a tantalum foil at an ultrahigh strain rate of [Formula: see text] ~2 × 10 8 to 3.5 × 10 8 s -1 . A maximal density drop of 8 to 10%, associated with the onset of spallation at a spall strength of ~17 GPa, was directly measured using x-ray diffraction. The experimental results of density evolution agree well with large-scale atomistic simulations of shock wave propagation and fracture of the sample. Our experimental technique opens a new pathway to the investigation of ultrahigh strain-rate phenomena in materials at the atomic scale, including high-speed crack dynamics and stress-induced solid-solid phase transitions.

Dynamic fracture of tantalum under extreme tensile stress

PubMed Central

Albertazzi, Bruno; Ozaki, Norimasa; Zhakhovsky, Vasily; Faenov, Anatoly; Habara, Hideaki; Harmand, Marion; Hartley, Nicholas; Ilnitsky, Denis; Inogamov, Nail; Inubushi, Yuichi; Ishikawa, Tetsuya; Katayama, Tetsuo; Koyama, Takahisa; Koenig, Michel; Krygier, Andrew; Matsuoka, Takeshi; Matsuyama, Satoshi; McBride, Emma; Migdal, Kirill Petrovich; Morard, Guillaume; Ohashi, Haruhiko; Okuchi, Takuo; Pikuz, Tatiana; Purevjav, Narangoo; Sakata, Osami; Sano, Yasuhisa; Sato, Tomoko; Sekine, Toshimori; Seto, Yusuke; Takahashi, Kenjiro; Tanaka, Kazuo; Tange, Yoshinori; Togashi, Tadashi; Tono, Kensuke; Umeda, Yuhei; Vinci, Tommaso; Yabashi, Makina; Yabuuchi, Toshinori; Yamauchi, Kazuto; Yumoto, Hirokatsu; Kodama, Ryosuke

2017-01-01

The understanding of fracture phenomena of a material at extremely high strain rates is a key issue for a wide variety of scientific research ranging from applied science and technological developments to fundamental science such as laser-matter interaction and geology. Despite its interest, its study relies on a fine multiscale description, in between the atomic scale and macroscopic processes, so far only achievable by large-scale atomic simulations. Direct ultrafast real-time monitoring of dynamic fracture (spallation) at the atomic lattice scale with picosecond time resolution was beyond the reach of experimental techniques. We show that the coupling between a high-power optical laser pump pulse and a femtosecond x-ray probe pulse generated by an x-ray free electron laser allows detection of the lattice dynamics in a tantalum foil at an ultrahigh strain rate of ε. ~2 × 108 to 3.5 × 108 s−1. A maximal density drop of 8 to 10%, associated with the onset of spallation at a spall strength of ~17 GPa, was directly measured using x-ray diffraction. The experimental results of density evolution agree well with large-scale atomistic simulations of shock wave propagation and fracture of the sample. Our experimental technique opens a new pathway to the investigation of ultrahigh strain-rate phenomena in materials at the atomic scale, including high-speed crack dynamics and stress-induced solid-solid phase transitions. PMID:28630909

Low-loss adiabatically-tapered high-contrast gratings for slow-wave modulators on SOI

NASA Astrophysics Data System (ADS)

Sciancalepore, Corrado; Hassan, Karim; Ferrotti, Thomas; Harduin, Julie; Duprez, Hélène; Menezo, Sylvie; Ben Bakir, Badhise

2015-02-01

In this communication, we report about the design, fabrication, and testing of Silicon-based photonic integrated circuits (Si-PICs) including low-loss flat-band slow-light high-contrast-gratings (HCGs) waveguides at 1.31 μm. The light slowdown is achieved in 300-nm-thick silicon-on-insulator (SOI) rib waveguides by patterning adiabatically-tapered highcontrast gratings, capable of providing slow-light propagation with extremely low optical losses, back-scattering, and Fabry-Pérot noise. In detail, the one-dimensional (1-D) grating architecture is capable to provide band-edge group indices ng ~ 25, characterized by overall propagation losses equivalent to those of the index-like propagation regime (~ 1-2 dB/cm). Such photonic band-edge slow-light regime at low propagation losses is made possible by the adiabatic apodization of such 1-D HCGs, thus resulting in a win-win approach where light slow-down regime is reached without additional optical losses penalty. As well as that, a tailored apodization optimized via genetic algorithms allows the flattening of slow-light regime over the wavelength window of interest, therefore suiting well needs for group index stability for modulation purposes and non-linear effects generation. In conclusion, such architectures provide key features suitable for power-efficient high-speed modulators in silicon as well as an extremely low-loss building block for non-linear optics (NLO) which is now available in the Si photonics toolbox.

Significant Stability Enhancement in High-Efficiency Polymer:Fullerene Bulk Heterojunction Solar Cells by Blocking Ultraviolet Photons from Solar Light.

PubMed

Jeong, Jaehoon; Seo, Jooyeok; Nam, Sungho; Han, Hyemi; Kim, Hwajeong; Anthopoulos, Thomas D; Bradley, Donal D C; Kim, Youngkyoo

2016-04-01

Achievement of extremely high stability for inverted-type polymer:fullerene solar cells is reported, which have bulk heterojunction (BHJ) layers consisting of poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene-alt-3-fluorothieno[3,4-b]thiophene-2-carboxylate] (PTB7-Th) and [6,6]-phenyl-C71-butyric acid methyl ester (PC 71 BM), by employing UV-cut filter (UCF) that is mounted on the front of glass substrates. The UCF can block most of UV photons below 403 nm at the expense of ≈20% reduction in the total intensity of solar light. Results show that the PTB7-Th:PC 71 BM solar cell with UCF exhibits extremely slow decay in power conversion efficiency (PCE) but a rapidly decayed PCE is measured for the device without UCF. The poor device stability without UCF is ascribed to the oxidative degradation of constituent materials in the BHJ layers, which give rise to the formation of PC 71 BM aggregates, as measured with high resolution and scanning transmission electron microscopy and X-ray photoelectron spectroscopy. The device stability cannot be improved by simply inserting poly(ethylene imine) (PEI) interfacial layer without UCF, whereas the lifetime of the PEI-inserted PTB7-Th:PC 71 BM solar cells is significantly enhanced when UCF is attached.

X-Ray Polarimetry with GEMS

NASA Technical Reports Server (NTRS)

Strohmayer, Tod

2011-01-01

The polarization properties of cosmic X-ray sources are still largely unexplored. The Gravity and Extreme Magnetism SMEX (GEMS) will carry out the first sensitive X-ray polarization survey of a wide range of sources including; accreting compact objects (black holes and neutron stars), AGN, supernova remnants, magnetars and rotation-powered pulsars. GEMS employs grazing-incidence foil mirrors and novel time-projection chamber (TPC) polarimeters leveraging the photoelectric effect to achieve high polarization sensitivity in the 2 - 10 keV band. I will provide an update of the project status, illustrate the expected performance with several science examples, and provide a brief overview of the data analysis challenges

Computer aided flexible envelope designs

NASA Technical Reports Server (NTRS)

Resch, R. D.

1975-01-01

Computer aided design methods are presented for the design and construction of strong, lightweight structures which require complex and precise geometric definition. The first, flexible structures, is a unique system of modeling folded plate structures and space frames. It is possible to continuously vary the geometry of a space frame to produce large, clear spans with curvature. The second method deals with developable surfaces, where both folding and bending are explored with the observed constraint of available building materials, and what minimal distortion result in maximum design capability. Alternative inexpensive fabrication techniques are being developed to achieve computer defined enclosures which are extremely lightweight and mathematically highly precise.

[Treatment of hereditary angioedema].

PubMed

Qian, X

1990-06-01

Hereditary angioedema is a rare familial disease caused by the defect of complement C1esterase inhibitor (C1-INH). It is characterized by recurrent acute edema of the extremities, the face, the respiratory tract and the gastrointestinal tract. Acute laryngeal edema usually produces laryngeal obstruction. Two cases have been treated since 1986, one of them had been admitted for forty-five times because of recurrent acute laryngeal edema. Investigations showed two families with a high incidence of this disease. Laboratory examination showed a remarkable decrease of C1-INH and C4. Tracheotomy is indicated in patients with laryngeal edema. Great success was achieved in two patients treated with danazol.

High performance rotational vibration isolator

NASA Astrophysics Data System (ADS)

Sunderland, Andrew; Blair, David G.; Ju, Li; Golden, Howard; Torres, Francis; Chen, Xu; Lockwood, Ray; Wolfgram, Peter

2013-10-01

We present a new rotational vibration isolator with an extremely low resonant frequency of 0.055 ± 0.002 Hz. The isolator consists of two concentric spheres separated by a layer of water and joined by very soft silicone springs. The isolator reduces rotation noise at all frequencies above its resonance which is very important for airborne mineral detection. We show that more than 40 dB of isolation is achieved in a helicopter survey for rotations at frequencies between 2 Hz and 20 Hz. Issues affecting performance such as translation to rotation coupling and temperature are discussed. The isolator contains almost no metal, making it particularly suitable for electromagnetic sensors.

High performance rotational vibration isolator.

PubMed

Sunderland, Andrew; Blair, David G; Ju, Li; Golden, Howard; Torres, Francis; Chen, Xu; Lockwood, Ray; Wolfgram, Peter

2013-10-01

We present a new rotational vibration isolator with an extremely low resonant frequency of 0.055 ± 0.002 Hz. The isolator consists of two concentric spheres separated by a layer of water and joined by very soft silicone springs. The isolator reduces rotation noise at all frequencies above its resonance which is very important for airborne mineral detection. We show that more than 40 dB of isolation is achieved in a helicopter survey for rotations at frequencies between 2 Hz and 20 Hz. Issues affecting performance such as translation to rotation coupling and temperature are discussed. The isolator contains almost no metal, making it particularly suitable for electromagnetic sensors.

A study of enhancing critical current densities (J(sub c)) and critical temperature (T(sub c)) of high-temperature superconductors

NASA Technical Reports Server (NTRS)

Vlasse, Marcus

1992-01-01

The development of pure phase 123 and Bi-based 2223 superconductors has been optimized. The pre-heat processing appears to be a very important parameter in achieving optimal physical properties. The synthesis of pure phases in the Bi-based system involves effects due to oxygen partial pressure, time, and temperature. Orientation/melt-sintering effects include the extreme c-axis orientation of Yttrium 123 and Bismuth 2223, 2212, and 2201 phases. This orientation is conductive to increasing critical currents. A procedure was established to substitute Sr for Ba in Y-123 single crystals.

Notes on the uwainat oil rim development, Maydan Mahzam and Bul Hanine Fields, offshore Qatar

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

Hamam, K.A.

As a result of reservoir simulation studies of the Uwainat reservoirs (Maydan Mahzam and Bul Hanine Fields), drilling to the Uwainat oil rim target became very ''tight'' with a very limited vertical tolerance. To achieve drilling to the tight target requires a precise position of the well at the top of the Lower Arab IV reservoir (a reliable marker) and an accurate isochore of the Lower Arab IV - Uwainat. The discussion shows that the level of accuracy needed in determining both the actual subsea well position and in constructing the depth contours of the reservoirs is extremely high.

Efficient entanglement distribution over 200 kilometers.

PubMed

Dynes, J F; Takesue, H; Yuan, Z L; Sharpe, A W; Harada, K; Honjo, T; Kamada, H; Tadanaga, O; Nishida, Y; Asobe, M; Shields, A J

2009-07-06

Here we report the first demonstration of entanglement distribution over a record distance of 200 km which is of sufficient fidelity to realize secure communication. In contrast to previous entanglement distribution schemes, we use detection elements based on practical avalanche photodiodes (APDs) operating in a self-differencing mode. These APDs are low-cost, compact and easy to operate requiring only electrical cooling to achieve high single photon detection efficiency. The self-differencing APDs in combination with a reliable parametric down-conversion source demonstrate that entanglement distribution over ultra-long distances has become both possible and practical. Consequently the outlook is extremely promising for real world entanglement-based communication between distantly separated parties.

CO2 laser oscillators for laser radar applications

NASA Technical Reports Server (NTRS)

Freed, C.

1990-01-01

This paper reviews the spectral purity, frequency stability, and long-term stabilization of newly developed CO2 isotope lasers. Extremely high spectral purity, and short-term stability of less than 1.5 x 10 to the -13th have been achieved. A brief description on using CO2 isotope lasers as secondary frequency standards and in optical radar is given. The design and output characteristics of a single frequency, TEM00q mode, variable pulse width, hybrid TE CO2 laser system is also described. The frequency chirp in the output has been measured and almost completely eliminated by means of a novel technique.

Tapered-fiber-based refractive index sensor at an air/solution interface.

PubMed

Lu, Ping; Harris, Jeremie; Wang, Xiaozhen; Lin, Ganbin; Chen, Liang; Bao, Xiaoyi

2012-10-20

An approach to achieve refractive index sensing at an air and aqueous glycerol solution interface is proposed using a tapered-fiber-based microfiber Mach-Zehnder interferometer (MFMZI). Compared to a surrounding uniform medium of air or solutions, the spectral interference visibility of the MFMZI at the air/solution interface is significantly reduced due to a weak coupling between the fundamental cladding mode and high-order asymmetric cladding modes, which are extremely sensitive to the external refractive index. The MFMZI is experimentally demonstrated as an evanescent wave refractive index sensor to measure concentrations of glycerol solutions by monitoring average power attenuation of the tapered fiber.

Re{sup 3+} : YAG laser ceramics: synthesis, optical properties and laser characteristics

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

Bagayev, S N; Vatnik, S M; Vedin, I A

2015-05-31

Highly transparent yttrium aluminium garnet ceramics doped with holmium or ytterbium or neodymium are synthesised. The ceramics were made of a mixture of nanopowders synthesised by laser ablation. The structural and spectral characteristics of ceramics are studied. In the samples with holmium Ho{sup 3+} and neodymium Nd{sup 3+} ions, lasing was achieved with a slope efficiency of 40% and 35.3%, respectively; the maximum laser power exceeded 4 W. The internal absorption and scattering losses for 1% Nd : YAG ceramics are estimated to be 1.6 × 10{sup -2} cm{sup -1}. (extreme light fields and their applications)

Global issues and opportunities for optimized retinoblastoma care.

PubMed

Gallie, Brenda L; Zhao, Junyang; Vandezande, Kirk; White, Abigail; Chan, Helen S L

2007-12-01

The RB1 gene is important in all human cancers. Studies of human retinoblastoma point to a rare retinal cell with extreme dependency on RB1 for initiation but not progression to full malignancy. In developed countries, genetic testing within affected families can predict children at high risk of retinoblastoma before birth; chemotherapy with local therapy often saves eyes and vision; and mortality is 4%. In less developed countries where 92% of children with retinoblastoma are born, mortality reaches 90%. Global collaboration is building for the dramatic change in mortality that awareness, simple expertise and therapies could achieve in less developed countries. Copyright 2007 Wiley-Liss, Inc.

Quadrant anode image sensor

NASA Technical Reports Server (NTRS)

Lampton, M.; Malina, R. F.

1976-01-01

A position-sensitive event-counting electronic readout system for microchannel plates (MCPs) is described that offers the advantages of high spatial resolution and fast time resolution. The technique relies upon a four-quadrant electron-collecting anode located behind the output face of the microchannel plate, so that the electron cloud from each detected event is partly intercepted by each of the four quadrants. The relative amounts of charge collected by each quadrant depend on event position, permitting each event to be localized with two ratio circuits. A prototype quadrant anode system for ion, electron, and extreme ultraviolet imaging is described. The spatial resolution achieved, about 10 microns, allows individual MCP channels to be distinguished.

Future changes in hydro-climatic extremes in the Upper Indus, Ganges, and Brahmaputra River basins

PubMed Central

Lutz, Arthur F.; Nepal, Santosh; Khanal, Sonu; Pradhananga, Saurav; Shrestha, Arun B.; Immerzeel, Walter W.

2017-01-01

Future hydrological extremes, such as floods and droughts, may pose serious threats for the livelihoods in the upstream domains of the Indus, Ganges, Brahmaputra. For this reason, the impacts of climate change on future hydrological extremes is investigated in these river basins. We use a fully-distributed cryospheric-hydrological model to simulate current and future hydrological fluxes and force the model with an ensemble of 8 downscaled General Circulation Models (GCMs) that are selected from the RCP4.5 and RCP8.5 scenarios. The model is calibrated on observed daily discharge and geodetic mass balances. The climate forcing and the outputs of the hydrological model are used to evaluate future changes in climatic extremes, and hydrological extremes by focusing on high and low flows. The outcomes show an increase in the magnitude of climatic means and extremes towards the end of the 21st century where climatic extremes tend to increase stronger than climatic means. Future mean discharge and high flow conditions will very likely increase. These increases might mainly be the result of increasing precipitation extremes. To some extent temperature extremes might also contribute to increasing discharge extremes, although this is highly dependent on magnitude of change in temperature extremes. Low flow conditions may occur less frequently, although the uncertainties in low flow projections can be high. The results of this study may contribute to improved understanding on the implications of climate change for the occurrence of future hydrological extremes in the Hindu Kush–Himalayan region. PMID:29287098

Probabilistic forecasting of extreme weather events based on extreme value theory

NASA Astrophysics Data System (ADS)

Van De Vyver, Hans; Van Schaeybroeck, Bert

2016-04-01

Extreme events in weather and climate such as high wind gusts, heavy precipitation or extreme temperatures are commonly associated with high impacts on both environment and society. Forecasting extreme weather events is difficult, and very high-resolution models are needed to describe explicitly extreme weather phenomena. A prediction system for such events should therefore preferably be probabilistic in nature. Probabilistic forecasts and state estimations are nowadays common in the numerical weather prediction community. In this work, we develop a new probabilistic framework based on extreme value theory that aims to provide early warnings up to several days in advance. We consider the combined events when an observation variable Y (for instance wind speed) exceeds a high threshold y and its corresponding deterministic forecasts X also exceeds a high forecast threshold y. More specifically two problems are addressed:} We consider pairs (X,Y) of extreme events where X represents a deterministic forecast, and Y the observation variable (for instance wind speed). More specifically two problems are addressed: Given a high forecast X=x_0, what is the probability that Y>y? In other words: provide inference on the conditional probability: [ Pr{Y>y|X=x_0}. ] Given a probabilistic model for Problem 1, what is the impact on the verification analysis of extreme events. These problems can be solved with bivariate extremes (Coles, 2001), and the verification analysis in (Ferro, 2007). We apply the Ramos and Ledford (2009) parametric model for bivariate tail estimation of the pair (X,Y). The model accommodates different types of extremal dependence and asymmetry within a parsimonious representation. Results are presented using the ensemble reforecast system of the European Centre of Weather Forecasts (Hagedorn, 2008). Coles, S. (2001) An Introduction to Statistical modelling of Extreme Values. Springer-Verlag.Ferro, C.A.T. (2007) A probability model for verifying deterministic forecasts of extreme events. Wea. Forecasting {22}, 1089-1100.Hagedorn, R. (2008) Using the ECMWF reforecast dataset to calibrate EPS forecasts. ECMWF Newsletter, {117}, 8-13.Ramos, A., Ledford, A. (2009) A new class of models for bivariate joint tails. J.R. Statist. Soc. B {71}, 219-241.

Carbon Nanotube Bundle Array Cold Cathodes for THz Vacuum Tube Sources

NASA Astrophysics Data System (ADS)

Manohara, Harish M.; Toda, Risaku; Lin, Robert H.; Liao, Anna; Bronikowski, Michael J.; Siegel, Peter H.

2009-12-01

We present high performance cold cathodes composed of arrays of carbon nanotube bundles that routinely produce > 15 A/cm2 at applied fields of 5 to 8 V/µm without any beam focusing. They have exhibited robust operation in poor vacuums of 10-6 to 10-4 Torr- a typically achievable range inside hermetically sealed microcavities. A new double-SOI process was developed to monolithically integrate a gate and additional beam tailoring electrodes. The ability to design the electrodes for specific requirements makes carbon nanotube field emission sources extremely flexible. The lifetime of these cathodes is found to be affected by two effects: a gradual decay of emission due to anode sputtering, and catastrophic failure because of dislodging of CNT bundles at high fields ( > 10 V/µm).

Crew collaboration in space: a naturalistic decision-making perspective

NASA Technical Reports Server (NTRS)

Orasanu, Judith

2005-01-01

Successful long-duration space missions will depend on the ability of crewmembers to respond promptly and effectively to unanticipated problems that arise under highly stressful conditions. Naturalistic decision making (NDM) exploits the knowledge and experience of decision makers in meaningful work domains, especially complex sociotechnical systems, including aviation and space. Decision making in these ambiguous, dynamic, high-risk environments is a complex task that involves defining the nature of the problem and crafting a response to achieve one's goals. Goal conflicts, time pressures, and uncertain outcomes may further complicate the process. This paper reviews theory and research pertaining to the NDM model and traces some of the implications for space crews and other groups that perform meaningful work in extreme environments. It concludes with specific recommendations for preparing exploration crews to use NDM effectively.

The development and production of thermo-mechanically forged tool steel spur gears

NASA Technical Reports Server (NTRS)

Bamberger, E. N.

1973-01-01

A development program to establish the feasibility and applicability of high energy rate forging procedures to tool steel spur gears was performed. Included in the study were relatively standard forging procedures as well as a thermo-mechanical process termed ausforming. The subject gear configuration utilized was essentially a standard spur gear having 28 teeth, a pitch diameter of 3.5 inches and a diametral pitch of 8. Initially it had been planned to use a high contact ratio gear design, however, a comprehensive evaluation indicated that severe forging problems would be encountered as a result of the extremely small teeth required by this type of design. The forging studies were successful in achieving gear blanks having integrally formed teeth using both standard and thermo-mechanical forging procedures.

Laser based imaging of time depending microscopic scenes with strong light emission

NASA Astrophysics Data System (ADS)

Hahlweg, Cornelius; Wilhelm, Eugen; Rothe, Hendrik

2011-10-01

Investigating volume scatterometry methods based on short range LIDAR devices for non-static objects we achieved interesting results aside the intended micro-LIDAR: the high speed camera recording of the illuminated scene of an exploding wire -intended for Doppler LIDAR tests - delivered a very effective method of observing details of objects with extremely strong light emission. As a side effect a schlieren movie is gathered without any special effort. The fact that microscopic features of short time processes with high emission and material flow might be imaged without endangering valuable equipment makes this technique at least as interesting as the intended one. So we decided to present our results - including latest video and photo material - instead of a more theoretical paper on our progress concerning the primary goal.

Passive shimming of the fringe field of a superconducting magnet for ultra-low field hyperpolarized noble gas MRI.

PubMed

Parra-Robles, Juan; Cross, Albert R; Santyr, Giles E

2005-05-01

Hyperpolarized noble gases (HNGs) provide exciting possibilities for MR imaging at ultra-low magnetic field strengths (<0.15 T) due to the extremely high polarizations available from optical pumping. The fringe field of many superconductive magnets used in clinical MR imaging can provide a stable magnetic field for this purpose. In addition to offering the benefit of HNG MR imaging alongside conventional high field proton MRI, this approach offers the other useful advantage of providing different field strengths at different distances from the magnet. However, the extremely strong field gradients associated with the fringe field present a major challenge for imaging since impractically high active shim currents would be required to achieve the necessary homogeneity. In this work, a simple passive shimming method based on the placement of a small number of ferromagnetic pieces is proposed to reduce the fringe field inhomogeneities to a level that can be corrected using standard active shims. The method explicitly takes into account the strong variations of the field over the volume of the ferromagnetic pieces used to shim. The method is used to obtain spectra in the fringe field of a high-field (1.89 T) superconducting magnet from hyperpolarized 129Xe gas samples at two different ultra-low field strengths (8.5 and 17 mT). The linewidths of spectra measured from imaging phantoms (30 Hz) indicate a homogeneity sufficient for MRI of the rat lung.

Phosphorescent cyclometalated complexes for efficient blue organic light-emitting diodes

PubMed Central

Suzuri, Yoshiyuki; Oshiyama, Tomohiro; Ito, Hiroto; Hiyama, Kunihisa; Kita, Hiroshi

2014-01-01

Phosphorescent emitters are extremely important for efficient organic light-emitting diodes (OLEDs), which attract significant attention. Phosphorescent emitters, which have a high phosphorescence quantum yield at room temperature, typically contain a heavy metal such as iridium and have been reported to emit blue, green and red light. In particular, the blue cyclometalated complexes with high efficiency and high stability are being developed. In this review, we focus on blue cyclometalated complexes. Recent progress of computational analysis necessary to design a cyclometalated complex is introduced. The prediction of the radiative transition is indispensable to get an emissive cyclometalated complex. We summarize four methods to control phosphorescence peak of the cyclometalated complex: (i) substituent effect on ligands, (ii) effects of ancillary ligands on heteroleptic complexes, (iii) design of the ligand skeleton, and (iv) selection of the central metal. It is considered that novel ligand skeletons would be important to achieve both a high efficiency and long lifetime in the blue OLEDs. Moreover, the combination of an emitter and a host is important as well as the emitter itself. According to the dependences on the combination of an emitter and a host, the control of exciton density of the triplet is necessary to achieve both a high efficiency and a long lifetime, because the annihilations of the triplet state cause exciton quenching and material deterioration. PMID:27877712

Phosphorescent cyclometalated complexes for efficient blue organic light-emitting diodes

NASA Astrophysics Data System (ADS)

Suzuri, Yoshiyuki; Oshiyama, Tomohiro; Ito, Hiroto; Hiyama, Kunihisa; Kita, Hiroshi

2014-10-01

Phosphorescent emitters are extremely important for efficient organic light-emitting diodes (OLEDs), which attract significant attention. Phosphorescent emitters, which have a high phosphorescence quantum yield at room temperature, typically contain a heavy metal such as iridium and have been reported to emit blue, green and red light. In particular, the blue cyclometalated complexes with high efficiency and high stability are being developed. In this review, we focus on blue cyclometalated complexes. Recent progress of computational analysis necessary to design a cyclometalated complex is introduced. The prediction of the radiative transition is indispensable to get an emissive cyclometalated complex. We summarize four methods to control phosphorescence peak of the cyclometalated complex: (i) substituent effect on ligands, (ii) effects of ancillary ligands on heteroleptic complexes, (iii) design of the ligand skeleton, and (iv) selection of the central metal. It is considered that novel ligand skeletons would be important to achieve both a high efficiency and long lifetime in the blue OLEDs. Moreover, the combination of an emitter and a host is important as well as the emitter itself. According to the dependences on the combination of an emitter and a host, the control of exciton density of the triplet is necessary to achieve both a high efficiency and a long lifetime, because the annihilations of the triplet state cause exciton quenching and material deterioration.

Review of space radiation interaction with ZERODUR

NASA Astrophysics Data System (ADS)

Carré, Antoine; Westerhoff, Thomas; Hull, Tony; Doyle, D.

2017-09-01

ZERODUR has been and is still being successfully used as mirror substrates for a large number of space missions. Improvements in CNC machining at SCHOTT allow to achieve extremely light weighted substrates incorporating very thin ribs and face sheets. This paper is reviewing data published on the interaction of space radiation with ZERODUR. Additionally, this paper reports on considerations and experiments which are needed to confidently apply an updated model on ZERODUR behavior under space radiation for extremely light weighted ZERODUR substrates.

Challenges and Ideas to Achieve Wireless 100 Gb/s Transmission: An Overview of Challenges and Solutions within the German Research Foundation (DFG) Special Priority Program SPP1655

NASA Astrophysics Data System (ADS)

Kraemer, Rolf

2017-09-01

Wireless communications is one of the fastest growing technology fields, driving numerous other innovations in electronics. One challenging research area within the wireless field is to achieve much higher transmission rates. First products with up to 3 Gb/s are in the market. In the coming years we predict this speed growing quickly up to and beyond 100 Gb/s. Today it is an open question how we can realize a wireless system at this speed. If we intend to use such systems in a mobile environment, we can only afford to spend approximately 1-10 pW/b for the end-to-end communication. This includes RF-transmission and all processing and protocol steps. The SPP1655 of the DFG was set up to investigate new paradigms for achieving the 100 Gb/s wireless transmission goal. Within 11 coordinated projects researchers from all over Germany are addressing several relevant issues ranging from the antennas and RF-Frontend, baseband-processing and error correction to protocol processing. A number of limitations of current approaches have to be investigated and new algorithms must be found in order to achieve the intended goal. One of the big challenges is finding the correct balance between analog and digital signal processing to achieve an extremely high performance at very low energy consumption. Another challenge is to find a good balance between bandwidth and bandwidth efficiency to achieve the 100 Gbps goal. Finally, protocol processing will need new approaches to decouple the central processor of a computer from the high-end input/output operations. Within this editorial we will address the main challenges and briefly outline the approaches of the running projects. The rest of this special issue will be devoted to more detailed descriptions and achievements of the individual projects of SPP1655.

Endoscopic and laparoscopic treatment of gastroesophageal reflux.

PubMed

Watson, David I; Immanuel, Arul

2010-04-01

Gastroesophageal reflux is extremely common in Western countries. For selected patients, there is an established role for the surgical treatment of reflux, and possibly an emerging role for endoscopic antireflux procedures. Randomized trials have compared medical versus surgical management, laparoscopic versus open surgery and partial versus total fundoplications. However, the evidence base for endoscopic procedures is limited to some small sham-controlled studies, and cohort studies with short-term follow-up. Laparoscopic fundoplication has been shown to be an effective antireflux operation. It facilitates quicker convalescence and is associated with fewer complications, but has a similar longer term outcome compared with open antireflux surgery. In most randomized trials, antireflux surgery achieves at least as good control of reflux as medical therapy, and these studies support a wider application of surgery for the treatment of moderate-to-severe reflux. Laparoscopic partial fundoplication is an effective surgical procedure with fewer side effects, and it may achieve high rates of patient satisfaction at late follow-up. Many of the early endoscopic antireflux procedures have failed to achieve effective reflux control, and they have been withdrawn from the market. Newer procedures have the potential to fashion a surgical fundoplication. However, at present there is insufficient evidence to establish the safety and efficacy of endoscopic procedures for the treatment of gastroesophageal reflux, and no endoscopic procedure has achieved equivalent reflux control to that achieved by surgical fundoplication.

Progress towards the Millennium Development Goals in a community of extreme poverty: local vs. national disparities in Peru.

PubMed

Gyorkos, Theresa W; Joseph, Serene A; Casapía, Martin

2009-06-01

Standard indicators are being used worldwide to track progress towards achieving the Millennium Development Goals (MDGs). These are usually at country level and do not accurately reflect within-country variability of progress towards the targets. This may lead to lack of attention and under-resourcing of the most vulnerable populations. Therefore, the objective of this study was to compare selected standard MDG indicators at country level and community level in Peru. As MDG indicators we selected: (i) moderate to severe and severe underweight in children under 5 years old; (ii) immunization against measles in 1-year olds; (iii) births attended by skilled health professionals and (iv) youth unemployment. Country-level data for Peru were obtained from United Nations published sources. Community-level data were obtained from a household survey conducted in 2005-2006 in Belén, a community of extreme poverty in the Amazon region. Belén indicators were consistently less favourable than country-level indicators, and indicators even differed between zones of high and low socioeconomic status within Belén itself. Compared to MDG indicators at the national level in Peru, the population of Belén experiences intra-country regional disparities in important health and social outcomes. Improving the coverage and quality of interventions and services in this community is essential. Other vulnerable populations in Peru should also be identified and targeted so that they can benefit from, and ultimately contribute to, progress in achieving the MDGs.

Sympathetic blocks for the treatment of complex regional pain syndrome: A case series.

PubMed

Gungor, Semih; Aiyer, Rohit; Baykoca, Buse

2018-05-01

To present the successful treatment of complex regional pain syndrome type -1 utilizing sympathetic blocks. Severe pain interfering with activities of daily living and temporary disability secondary to complex regional pain syndrome. Complex regional pain syndrome type-1 with involvement of lower extremity (2 patients), and upper extremity (1 patient). We report the management of 3 patients with diagnosis of complex regional pain syndrome type-1 by early institution of sympathetic blocks for diagnostic and therapeutic purposes. All 3 patients were able to tolerate physical therapy only after adequate pain relief had been achieved with institution of sympathetic blocks. All 3 patients responded very favorably to sympathetic blocks with dramatic reversal of pathology. All patients reported almost complete resolution of pain, symptoms, and signs within 6 months duration after diagnosis of complex regional pain syndrome. All 3 patients were able to wean their pain medications and achieve normal activities of daily living without any significant limitations. All patients were able to return to full-time employment. Treatment options are limited and there is lack of high quality research regarding the efficacy of sympathetic blocks in the treatment of complex regional pain syndrome. As presented in this case series, sympathetic blocks maybe very effective in the treatment of complex regional pain syndrome in a subset of patients. Thus, early institution of sympathetic blocks should be considered in complex regional pain syndrome prior to physical therapy and consideration of more invasive pain management interventions.

Extreme Fire Severity Patterns in Topographic, Convective and Wind-Driven Historical Wildfires of Mediterranean Pine Forests

PubMed Central

Lecina-Diaz, Judit; Alvarez, Albert; Retana, Javier

2014-01-01

Crown fires associated with extreme fire severity are extremely difficult to control. We have assessed fire severity using differenced Normalized Burn Ratio (dNBR) from Landsat imagery in 15 historical wildfires of Pinus halepensis Mill. We have considered a wide range of innovative topographic, fuel and fire behavior variables with the purposes of (1) determining the variables that influence fire severity patterns among fires (considering the 15 wildfires together) and (2) ascertaining whether different variables affect extreme fire severity within the three fire types (topographic, convective and wind-driven fires). The among-fires analysis showed that fires in less arid climates and with steeper slopes had more extreme severity. In less arid conditions there was more crown fuel accumulation and closer forest structures, promoting high vertical and horizontal fuel continuity and extreme fire severity. The analyses carried out for each fire separately (within fires) showed more extreme fire severity in areas in northern aspects, with steeper slopes, with high crown biomass and in climates with more water availability. In northern aspects solar radiation was lower and fuels had less water limitation to growth which, combined with steeper slopes, produced more extreme severity. In topographic fires there was more extreme severity in northern aspects with steeper slopes and in areas with more water availability and high crown biomass; in convection-dominated fires there was also more extreme fire severity in northern aspects with high biomass; while in wind-driven fires there was only a slight interaction between biomass and water availability. This latter pattern could be related to the fact that wind-driven fires spread with high wind speed, which could have minimized the effect of other variables. In the future, and as a consequence of climate change, new zones with high crown biomass accumulated in non-common drought areas will be available to burn as extreme severity wildfires. PMID:24465492

Extreme fire severity patterns in topographic, convective and wind-driven historical wildfires of Mediterranean pine forests.

PubMed

Lecina-Diaz, Judit; Alvarez, Albert; Retana, Javier

2014-01-01

Crown fires associated with extreme fire severity are extremely difficult to control. We have assessed fire severity using differenced Normalized Burn Ratio (dNBR) from Landsat imagery in 15 historical wildfires of Pinus halepensis Mill. We have considered a wide range of innovative topographic, fuel and fire behavior variables with the purposes of (1) determining the variables that influence fire severity patterns among fires (considering the 15 wildfires together) and (2) ascertaining whether different variables affect extreme fire severity within the three fire types (topographic, convective and wind-driven fires). The among-fires analysis showed that fires in less arid climates and with steeper slopes had more extreme severity. In less arid conditions there was more crown fuel accumulation and closer forest structures, promoting high vertical and horizontal fuel continuity and extreme fire severity. The analyses carried out for each fire separately (within fires) showed more extreme fire severity in areas in northern aspects, with steeper slopes, with high crown biomass and in climates with more water availability. In northern aspects solar radiation was lower and fuels had less water limitation to growth which, combined with steeper slopes, produced more extreme severity. In topographic fires there was more extreme severity in northern aspects with steeper slopes and in areas with more water availability and high crown biomass; in convection-dominated fires there was also more extreme fire severity in northern aspects with high biomass; while in wind-driven fires there was only a slight interaction between biomass and water availability. This latter pattern could be related to the fact that wind-driven fires spread with high wind speed, which could have minimized the effect of other variables. In the future, and as a consequence of climate change, new zones with high crown biomass accumulated in non-common drought areas will be available to burn as extreme severity wildfires.

Quantifying the relationship between extreme air pollution events and extreme weather events

NASA Astrophysics Data System (ADS)

Zhang, Henian; Wang, Yuhang; Park, Tae-Won; Deng, Yi

2017-05-01

Extreme weather events can strongly affect surface air quality, which has become a major environmental factor to affect human health. Here, we examined the relationship between extreme ozone and PM2.5 (particular matter with an aerodynamic diameter less than 2.5 μm) events and the representative meteorological parameters such as daily maximum temperature (Tmax), minimum relative humidity (RHmin), and minimum wind speed (Vmin), using the location-specific 95th or 5th percentile threshold derived from historical reanalysis data (30 years for ozone and 10 years for PM2.5). We found that ozone and PM2.5 extremes were decreasing over the years, reflecting EPA's tightened standards and effort on reducing the corresponding precursor's emissions. Annual ozone and PM2.5 extreme days were highly correlated with Tmax and RHmin, especially in the eastern U.S. They were positively (negatively) correlated with Vmin in urban (rural and suburban) stations. The overlapping ratios of ozone extreme days with Tmax were fairly constant, about 32%, and tended to be high in fall and low in winter. Ozone extreme days were most sensitive to Tmax, then RHmin, and least sensitive to Vmin. The majority of ozone extremes occurred when Tmax was between 300 K and 320 K, RHmin was less than 40%, and Vmin was less than 3 m/s. The number of annual extreme PM2.5 days was highly positively correlated with the extreme RHmin/Tmax days, with correlation coefficient between PM2.5/RHmin highest in urban and suburban regions and the correlation coefficient between PM2.5/Tmax highest in rural area. Tmax has more impact on PM2.5 extreme over the eastern U.S. Extreme PM2.5 days were more likely to occur at low RH conditions in the central and southeastern U.S., especially during spring time, and at high RH conditions in the northern U.S. and the Great Plains. Most extreme PM2.5 events occurred when Tmax was between 300 K and 320 K and RHmin was between 10% and 50%. Extreme PM2.5 days usually occurred when Vmin was under 2 m/s. However, during spring season in the Southeast and fall season in Northwest, high winds were found to accompany extreme PM2.5 days, likely reflecting the impact of fire emissions.

A comprehensive scoring system to evaluate patient-centred risk factors regarding lower extremity amputation.

PubMed

Miller, M S; Newgent, E W; O'Connell, S M; Broadus, C

2017-10-01

Care of the patient with a presumed life- or limb-threatening lower extremity wound poses many challenges. The mindset regarding potential outcomes of such conditions is mostly driven by the experiences and expertise of those providing the care. This mindset generally appears as two primary actions presented to the afflicted patient: attempted resolution of the problem via medical, surgical or combination treatment, with the hope of low recurrence risk, or exacerbation and amputation-amputations at a level sufficient to, at least in the mind of the surgeon, eliminate the problem. Achieving the former outcome is dependent on a number of factors associated with both patient and caregiver. If healing is achieved, the secondary goal of prevention of recurrence may be no less arduous, with failure most likely resulting in amputation. Clearly, these considerations appear to be based more on the health professionals perception, of the patient's physical and medical status rather than on patient-centred considerations. This article will review considerations and recommendations for lower extremity amputation, and the short- and long-term implications. Based on our research, there is clear need for a set of criteria against which to weigh not just the medical issues, but also definitive patient-centred issues when considering a lower extremity amputation. We offer a set of patient-centred, easily verified and recognised criteria that we believe addresses this need. The goal of the Miller-Newgent Amputation Scale (MENACE) is to provide a decision base from which to consider and evaluate all factors in determining the need for a lower extremity amputation. This involves identification of patient-centred issues, which are likely to produce satisfactory short- and long-term physical and quality-of-life outcomes if the amputation does proceed.