Role of oxygen functionality on the band structure evolution and conductance of reduced graphene oxide

NASA Astrophysics Data System (ADS)

Roy, Rajarshi; Thapa, Ranjit; Chakrabarty, Soubhik; Jha, Arunava; Midya, Priyanka R.; Kumar, E. Mathan; Chattopadhyay, Kalyan K.

2017-06-01

Here we report, structural and electrical transport properties of reduced graphene oxide as a function of oxygen bonding configuration. We find that mainly epoxy (Csbnd Osbnd C) and carbonyl (Cdbnd O) functional groups remain as major residual components after reduction using three different reducing agents. We calculate the band structure in the presence of epoxy and carbonyl groups and defects. Finally, we calculate the theoretical band mobility and find that it is less for the carbonyl with epoxy system. We correlate the distortion of linear dispersion and opening of bandgap at K-point with conductance for different graphene system in presence of oxygen moieties.

Myocardial deletion of transcription factor CHF1/Hey2 results in altered myocyte action potential and mild conduction system expansion but does not alter conduction system function or promote spontaneous arrhythmias.

PubMed

Hartman, Matthew E; Liu, Yonggang; Zhu, Wei-Zhong; Chien, Wei-Ming; Weldy, Chad S; Fishman, Glenn I; Laflamme, Michael A; Chin, Michael T

2014-07-01

CHF1/Hey2 is a Notch-responsive basic helix-loop-helix transcription factor involved in cardiac development. Common variants in Hey2 are associated with Brugada syndrome. We hypothesized that absence of CHF1/Hey2 would result in abnormal cellular electrical activity, altered cardiac conduction system (CCS) development, and increased arrhythmogenesis. We isolated neonatal CHF/Hey2-knockout (KO) cardiac myocytes and measured action potentials and ion channel subunit gene expression. We also crossed myocardial-specific CHF1/Hey2-KO mice with cardiac conduction system LacZ reporter mice and stained for conduction system tissue. We also performed ambulatory ECG monitoring for arrhythmias and heart rate variability. Neonatal cardiomyocytes from CHF1/Hey2-KO mice demonstrate a 50% reduction in action potential dV/dT, a 50-75% reduction in SCN5A, KCNJ2, and CACNA1C ion channel subunit gene expression, and an increase in delayed afterdepolarizations from 0/min to 12/min. CHF1/Hey2 cKO CCS-lacZ mice have a ∼3-fold increase in amount of CCS tissue. Ambulatory ECG monitoring showed no difference in cardiac conduction, arrhythmias, or heart rate variability. Wild-type cells or animals were used in all experiments. CHF1/Hey2 may contribute to Brugada syndrome by influencing the expression of SCN5A and formation of the cardiac conduction system, but its absence does not cause baseline conduction defects or arrhythmias in the adult mouse.-Hartman, M. E., Liu, Y., Zhu, W.-Z., Chien, W.-M., Weldy, C. S., Fishman, G. I., Laflamme, M. A., Chin, M. T. Myocardial deletion of transcription factor CHF1/Hey2 results in altered myocyte action potential and mild conduction system expansion but does not alter conduction system function or promote spontaneous arrhythmias. © FASEB.

Integrated command, control communication and computation system study

NASA Technical Reports Server (NTRS)

1981-01-01

The study was conducted in three phases: a functional requirements phase; a functional architecture phase; and a design plan phase. The major emphasis was on the functional architecture phase and the approaches used for its functional hierarchy, operations concept, and interfaces.

Material and Structural Design of Novel Binder Systems for High-Energy, High-Power Lithium-Ion Batteries

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

Shi, Ye; Zhou, Xingyi; Yu, Guihua

Developing high-performance battery systems requires the optimization of every battery component, from electrodes and electrolyte to binder systems. However, the conventional strategy to fabricate battery electrodes by casting a mixture of active materials, a nonconductive polymer binder, and a conductive additive onto a metal foil current collector usually leads to electronic or ionic bottlenecks and poor contacts due to the randomly distributed conductive phases. When high-capacity electrode materials are employed, the high stress generated during electrochemical reactions disrupts the mechanical integrity of traditional binder systems, resulting in decreased cycle life of batteries. Thus, it is critical to design novel bindermore » systems that can provide robust, low-resistance, and continuous internal pathways to connect all regions of the electrode. Here in this Account, we review recent progress on material and structural design of novel binder systems. Nonconductive polymers with rich carboxylic groups have been adopted as binders to stabilize ultrahigh-capacity inorganic electrodes that experience large volume or structural change during charge/discharge, due to their strong binding capability to active particles. To enhance the energy density of batteries, different strategies have been adopted to design multifunctional binder systems based on conductive polymers because they can play dual functions of both polymeric binders and conductive additives. We first present that multifunctional binder systems have been designed by tailoring the molecular structures of conductive polymers. Different functional groups are introduced to the polymeric backbone to enable multiple functionalities, allowing separated optimization of the mechanical and swelling properties of the binders without detrimental effect on electronic property. Then, we describe the design of multifunctional binder systems via rationally controlling their nano- and molecular structures, developing the conductive polymer gel binders with 3D framework nanostructures. These gel binders provide multiple functions owing to their structure derived properties. The gel framework facilitates both electronic and ionic transport owing to the continuous pathways for electrons and hierarchical pores for ion diffusion. The polymer coating formed on every particle acts as surface modification and prevents particle aggregation. The mechanically strong and ductile gel framework also sustains long-term stability of electrodes. In addition, the structures and properties of gel binders can be facilely tuned. We further introduce the development of multifunctional binders by hybridizing conductive polymers with other functional materials. Meanwhile mechanistic understanding on the roles that novel binders play in the electrochemical processes of batteries is also reviewed to reveal general design rules for future binder systems. We conclude with perspectives on their future development with novel multifunctionalities involved. Highly efficient binder systems with well-tailored molecular and nanostructures are critical to reach the entire volume of the battery and maximize energy use for high-energy and high-power lithium batteries. We hope this Account promotes further efforts toward synthetic control, fundamental investigation, and application exploration of multifunctional binder materials.« less

Material and Structural Design of Novel Binder Systems for High-Energy, High-Power Lithium-Ion Batteries

DOE PAGES

Shi, Ye; Zhou, Xingyi; Yu, Guihua

2017-10-05

Developing high-performance battery systems requires the optimization of every battery component, from electrodes and electrolyte to binder systems. However, the conventional strategy to fabricate battery electrodes by casting a mixture of active materials, a nonconductive polymer binder, and a conductive additive onto a metal foil current collector usually leads to electronic or ionic bottlenecks and poor contacts due to the randomly distributed conductive phases. When high-capacity electrode materials are employed, the high stress generated during electrochemical reactions disrupts the mechanical integrity of traditional binder systems, resulting in decreased cycle life of batteries. Thus, it is critical to design novel bindermore » systems that can provide robust, low-resistance, and continuous internal pathways to connect all regions of the electrode. Here in this Account, we review recent progress on material and structural design of novel binder systems. Nonconductive polymers with rich carboxylic groups have been adopted as binders to stabilize ultrahigh-capacity inorganic electrodes that experience large volume or structural change during charge/discharge, due to their strong binding capability to active particles. To enhance the energy density of batteries, different strategies have been adopted to design multifunctional binder systems based on conductive polymers because they can play dual functions of both polymeric binders and conductive additives. We first present that multifunctional binder systems have been designed by tailoring the molecular structures of conductive polymers. Different functional groups are introduced to the polymeric backbone to enable multiple functionalities, allowing separated optimization of the mechanical and swelling properties of the binders without detrimental effect on electronic property. Then, we describe the design of multifunctional binder systems via rationally controlling their nano- and molecular structures, developing the conductive polymer gel binders with 3D framework nanostructures. These gel binders provide multiple functions owing to their structure derived properties. The gel framework facilitates both electronic and ionic transport owing to the continuous pathways for electrons and hierarchical pores for ion diffusion. The polymer coating formed on every particle acts as surface modification and prevents particle aggregation. The mechanically strong and ductile gel framework also sustains long-term stability of electrodes. In addition, the structures and properties of gel binders can be facilely tuned. We further introduce the development of multifunctional binders by hybridizing conductive polymers with other functional materials. Meanwhile mechanistic understanding on the roles that novel binders play in the electrochemical processes of batteries is also reviewed to reveal general design rules for future binder systems. We conclude with perspectives on their future development with novel multifunctionalities involved. Highly efficient binder systems with well-tailored molecular and nanostructures are critical to reach the entire volume of the battery and maximize energy use for high-energy and high-power lithium batteries. We hope this Account promotes further efforts toward synthetic control, fundamental investigation, and application exploration of multifunctional binder materials.« less

The Palliative Function of Hostile Sexism among High and Low-Status Chilean Students

PubMed Central

Vargas-Salfate, Salvador

2017-01-01

Previous studies have demonstrated that justifying the social, economic, and political systems is associated with psychological well-being, which has been termed as the palliative function of ideology. However, little research has been conducted on gender stereotypes among children, comparing by socioeconomic status. This study aimed to fill this gap in the system justification literature. We present data from the Chilean version of the International Survey of Children Well-Being (ISCWeB), which was conducted in 2012. We found that the palliative function of gender stereotypes is present among this sample, being qualified by a socioeconomic status by hostile gender stereotype interaction. In other words, the effect on the psychological well-being was observed in low-status, but not in high-status students. These results extend the previous knowledge about the palliative function of the ideology, suggesting why the low-status members of a society actively engage in system justification. PMID:29046657

Printed batteries and conductive patterns in technical textiles

NASA Astrophysics Data System (ADS)

Willert, Andreas; Meuser, Carmen; Baumann, Reinhard R.

2018-05-01

Various applications of functional devices need a tailored and reliable supply of electrical energy. Batteries are electrochemical systems that deliver energy for functional devices and applications. Due to the common use, several rigid types of batteries have been standardized. To fully integrate the battery into a product that is bendable, free in geometry and less than 1 mm thick, printing of power adaptable batteries is a challenging area of research. Therefore, the well-known zinc-manganese system, which is very promising due to its environmental sustainability and its simplicity, has been used to manufacture battery solutions on a new kind of substrate: technical textiles. Another challenge is the deposition of conductive patterns. At present, embroidery with metallic yarn is the only possibility to provide conducting paths on technical textiles, a time-consuming and elaborate process. Screen printed conductive pathways will generate a new momentum in the manufacturing of conductivity on textiles.

Research on modeling and conduction disturbance simulation of secondary power system in a device

NASA Astrophysics Data System (ADS)

Ding, Xu; Yu, Zhi-Yong; Jin, Rui

2017-06-01

To find electromagnetic interference (EMI) and other problems in the secondary power supply system design quickly and effectively, simulations are carried out under the Saber simulation software platform. The DC/DC converter model with complete performance and electromagnetic characteristics is established by combining parametric modeling with Mast language. By using the method of macro modeling, the hall current sensor and power supply filter model are established respectively based on the function, schematic diagram of the components. Also the simulation of the component model and the whole secondary power supply system are carried out. The simulation results show that the proposed model satisfies the functional requirements of the system and has high accuracy. At the same time, due to the ripple characteristics in the DC/DC converter modeling, it can be used as a conducted interference model to simulate the power bus conducted emission CE102 project under the condition that the simulated load is full, which provides a useful reference for the electromagnetic interference suppression of the system.

Excitation model of pacemaker cardiomyocytes of cardiac conduction system

NASA Astrophysics Data System (ADS)

Grigoriev, M.; Babich, L.

2015-11-01

Myocardium includes typical and atypical cardiomyocytes - pacemakers, which form the cardiac conduction system. Excitation from the atrioventricular node in normal conditions is possible only in one direction. Retrograde direction of pulses is impossible. The most important prerequisite for the work of cardiomyocytes is the anatomical integrity of the conduction system. Changes in contractile force of the cardiomyocytes, which appear periodically, are due to two mechanisms of self-regulation - heterometric and homeometric. Graphic course of the excitation pulse propagation along the heart muscle more accurately reveals the understanding of the arrhythmia mechanism. These models have the ability to visualize the essence of excitation dynamics. However, they do not have the proper forecasting function for result estimation. Integrative mathematical model enables further investigation of general laws of the myocardium active behavior, allows for determination of the violation mechanism of electrical and contractile function of cardiomyocytes. Currently, there is no full understanding of the topography of pacemakers and ionic mechanisms. There is a need for the development of direction of mathematical modeling and comparative studies of the electrophysiological arrangement of cells of atrioventricular connection and ventricular conduction system.

Linear functional minimization for inverse modeling

DOE PAGES

Barajas-Solano, David A.; Wohlberg, Brendt Egon; Vesselinov, Velimir Valentinov; ...

2015-06-01

In this paper, we present a novel inverse modeling strategy to estimate spatially distributed parameters of nonlinear models. The maximum a posteriori (MAP) estimators of these parameters are based on a likelihood functional, which contains spatially discrete measurements of the system parameters and spatiotemporally discrete measurements of the transient system states. The piecewise continuity prior for the parameters is expressed via Total Variation (TV) regularization. The MAP estimator is computed by minimizing a nonquadratic objective equipped with the TV operator. We apply this inversion algorithm to estimate hydraulic conductivity of a synthetic confined aquifer from measurements of conductivity and hydraulicmore » head. The synthetic conductivity field is composed of a low-conductivity heterogeneous intrusion into a high-conductivity heterogeneous medium. Our algorithm accurately reconstructs the location, orientation, and extent of the intrusion from the steady-state data only. Finally, addition of transient measurements of hydraulic head improves the parameter estimation, accurately reconstructing the conductivity field in the vicinity of observation locations.« less

Integrated Training System for Air Force On-the-Job Training: Specification Development. Final Technical Paper.

ERIC Educational Resources Information Center

Carson, Stuart B.; And Others.

The Air Force conducted this study for two purposes: (1) to define the system of Air Force On-the-Job Training (OJT); and (2) to prepare a set of functional specifications for an integrated, base-level OJT evaluation and management system with linkages to the Major Commands and Air Staff. The study was conducted in four phases. During the first…

L-Band Digital Aeronautical Communications System Engineering - Concepts of Use, Systems Performance, Requirements, and Architectures

NASA Technical Reports Server (NTRS)

Zelkin, Natalie; Henriksen, Stephen

2010-01-01

This NASA Contractor Report summarizes and documents the work performed to develop concepts of use (ConUse) and high-level system requirements and architecture for the proposed L-band (960 to 1164 MHz) terrestrial en route communications system. This work was completed as a follow-on to the technology assessment conducted by NASA Glenn Research Center and ITT for the Future Communications Study (FCS). ITT assessed air-to-ground (A/G) communications concepts of use and operations presented in relevant NAS-level, international, and NAS-system-level documents to derive the appropriate ConUse relevant to potential A/G communications applications and services for domestic continental airspace. ITT also leveraged prior concepts of use developed during the earlier phases of the FCS. A middle-out functional architecture was adopted by merging the functional system requirements identified in the bottom-up assessment of existing requirements with those derived as a result of the top-down analysis of ConUse and higher level functional requirements. Initial end-to-end system performance requirements were derived to define system capabilities based on the functional requirements and on NAS-SR-1000 and the Operational Performance Assessment conducted as part of the COCR. A high-level notional architecture of the L-DACS supporting A/G communication was derived from the functional architecture and requirements.

Simulation system of arrhythmia using ActiveX control.

PubMed

Takeuchi, Akihiro; Hirose, Minoru; Hamada, Atsushi; Ikeda, Noriaki

2005-07-01

A simulation system for arrhythmias has been developed using Windows-based software technology, ActiveX control. The cardiac module consists of six cells, the sinus, atrium, AV node, ventricle, and ectopic foci. The physiological properties of the cells, the automaticity and conduction delay, were modelled, respectively, by the phase response curve and the excitability recovery curve. Cell functions were implemented in the ActiveX control and incorporated into the cardiac module. The system draws the ECG sequence as a ladder diagram in real time. The system interactively shows diverse arrhythmias for various user settings of the cell function and bidirectional conduction between the cells. Users are able to experiment virtually by setting up a so-called electrophysiological stimulation. This system is useful for learning and for teaching the interaction between the cells and arrhythmias.

Framework Design and Influencing Factor Analysis of a Water Environmental Functional Zone-Based Effluent Trading System.

PubMed

Chen, Lei; Han, Zhaoxing; Li, Shuang; Shen, Zhenyao

2016-10-01

The efficacy of traditional effluent trading systems is questionable due to their neglect of seasonal hydrological variation and the creation of upstream hot spots within a watershed. Besides, few studies have been conducted to distinguish the impacts of each influencing factor on effluent trading systems outputs. In this study, a water environmental functional zone-based effluent trading systems framework was configured and a comprehensive analysis of its influencing factors was conducted. This proposed water environmental functional zone-based effluent trading systems was then applied for the control of chemical oxygen demand in the Beiyun River watershed, Beijing, China. Optimal trading results highlighted the integration of water quality constraints and different hydrological seasons, especially for downstream dischargers. The optimal trading of each discharger, in terms of pollutant reduction load and abatement cost, is greatly influenced by environmental and political factors such as background water quality, the location of river assessment points, and tradable discharge permits. In addition, the initial permit allowance has little influence on the market as a whole but does impact the individual discharger. These results provide information that is critical to understanding the impact of policy design on the functionality of an effluent trading systems.

Framework Design and Influencing Factor Analysis of a Water Environmental Functional Zone-Based Effluent Trading System

NASA Astrophysics Data System (ADS)

Chen, Lei; Han, Zhaoxing; Li, Shuang; Shen, Zhenyao

2016-10-01

The efficacy of traditional effluent trading systems is questionable due to their neglect of seasonal hydrological variation and the creation of upstream hot spots within a watershed. Besides, few studies have been conducted to distinguish the impacts of each influencing factor on effluent trading systems outputs. In this study, a water environmental functional zone-based effluent trading systems framework was configured and a comprehensive analysis of its influencing factors was conducted. This proposed water environmental functional zone-based effluent trading systems was then applied for the control of chemical oxygen demand in the Beiyun River watershed, Beijing, China. Optimal trading results highlighted the integration of water quality constraints and different hydrological seasons, especially for downstream dischargers. The optimal trading of each discharger, in terms of pollutant reduction load and abatement cost, is greatly influenced by environmental and political factors such as background water quality, the location of river assessment points, and tradable discharge permits. In addition, the initial permit allowance has little influence on the market as a whole but does impact the individual discharger. These results provide information that is critical to understanding the impact of policy design on the functionality of an effluent trading systems.

Correlation Function Approach for Estimating Thermal Conductivity in Highly Porous Fibrous Materials

NASA Technical Reports Server (NTRS)

Martinez-Garcia, Jorge; Braginsky, Leonid; Shklover, Valery; Lawson, John W.

2011-01-01

Heat transport in highly porous fiber networks is analyzed via two-point correlation functions. Fibers are assumed to be long and thin to allow a large number of crossing points per fiber. The network is characterized by three parameters: the fiber aspect ratio, the porosity and the anisotropy of the structure. We show that the effective thermal conductivity of the system can be estimated from knowledge of the porosity and the correlation lengths of the correlation functions obtained from a fiber structure image. As an application, the effects of the fiber aspect ratio and the network anisotropy on the thermal conductivity is studied.

Electrical Conductivity of Charged Particle Systems and Zubarev's Nonequilibrium Statistical Operator Method

NASA Astrophysics Data System (ADS)

Röpke, G.

2018-01-01

One of the fundamental problems in physics that are not yet rigorously solved is the statistical mechanics of nonequilibrium processes. An important contribution to describing irreversible behavior starting from reversible Hamiltonian dynamics was given by D. N. Zubarev, who invented the method of the nonequilibrium statistical operator. We discuss this approach, in particular, the extended von Neumann equation, and as an example consider the electrical conductivity of a system of charged particles. We consider the selection of the set of relevant observables. We show the relation between kinetic theory and linear response theory. Using thermodynamic Green's functions, we present a systematic treatment of correlation functions, but the convergence needs investigation. We compare different expressions for the conductivity and list open questions.

On the dielectric conductivity of molecular ionic liquids.

PubMed

Schröder, Christian; Steinhauser, Othmar

2009-09-21

The contribution of the conductivity to the spectrum of the generalized dielectric constant or susceptibility of molecular ionic liquids is analyzed, both in theoretical terms and computationally by means of molecular dynamics simulation of the concrete system 1-ethyl-3-methyl-imidazolium dicyanoamide at 300 K. As a central quantity the simulated current autocorrelation function is modeled by a carefully designed fit function. This not only gives a satisfactory numerical representation but yields the correct conductivity upon integration. In addition the fit function can be Fourier-Laplace transformed analytically. Both, the real and imaginary parts of the transform show expected behavior, in particular, the right limits for zero frequency. This altogether demonstrates that the components of the fit function are of physical relevance.

Optimal Decay of Wannier functions in Chern and Quantum Hall Insulators

NASA Astrophysics Data System (ADS)

Monaco, Domenico; Panati, Gianluca; Pisante, Adriano; Teufel, Stefan

2018-01-01

We investigate the localization properties of independent electrons in a periodic background, possibly including a periodic magnetic field, as e. g. in Chern insulators and in quantum Hall systems. Since, generically, the spectrum of the Hamiltonian is absolutely continuous, localization is characterized by the decay, as {|x| → ∞} , of the composite (magnetic) Wannier functions associated to the Bloch bands below the Fermi energy, which is supposed to be in a spectral gap. We prove the validity of a localization dichotomy in the following sense: either there exist exponentially localized composite Wannier functions, and correspondingly the system is in a trivial topological phase with vanishing Hall conductivity, or the decay of any composite Wannier function is such that the expectation value of the squared position operator, or equivalently of the Marzari-Vanderbilt localization functional, is {+ ∞} . In the latter case, the Bloch bundle is topologically non-trivial, and one expects a non-zero Hall conductivity.

A novel functional electrical stimulation-control system for restoring motor function of post-stroke hemiplegic patients

PubMed Central

Huang, Zonghao; Wang, Zhigong; Lv, Xiaoying; Zhou, Yuxuan; Wang, Haipeng; Zong, Sihao

2014-01-01

Hemiparesis is one of the most common consequences of stroke. Advanced rehabilitation techniques are essential for restoring motor function in hemiplegic patients. Functional electrical stimulation applied to the affected limb based on myoelectric signal from the unaffected limb is a promising therapy for hemiplegia. In this study, we developed a prototype system for evaluating this novel functional electrical stimulation-control strategy. Based on surface electromyography and a vector machine model, a self-administered, multi-movement, force-modulation functional electrical stimulation-prototype system for hemiplegia was implemented. This paper discusses the hardware design, the algorithm of the system, and key points of the self-oscillation-prone system. The experimental results demonstrate the feasibility of the prototype system for further clinical trials, which is being conducted to evaluate the efficacy of the proposed rehabilitation technique. PMID:25657728

Thinking about Digestive System in Early Childhood: A Comparative Study about Biological Knowledge

ERIC Educational Resources Information Center

AHI, Berat

2017-01-01

The current study aims to explore how children explain the concepts of biology and how biological knowledge develops across ages by focusing on the structure and functions of the digestive system. The study was conducted with 60 children. The data were collected through the interviews conducted within a think-aloud protocol. The interview data…

FLBEIA : A simulation model to conduct Bio-Economic evaluation of fisheries management strategies

NASA Astrophysics Data System (ADS)

Garcia, Dorleta; Sánchez, Sonia; Prellezo, Raúl; Urtizberea, Agurtzane; Andrés, Marga

Fishery systems are complex systems that need to be managed in order to ensure a sustainable and efficient exploitation of marine resources. Traditionally, fisheries management has relied on biological models. However, in recent years the focus on mathematical models which incorporate economic and social aspects has increased. Here, we present FLBEIA, a flexible software to conduct bio-economic evaluation of fisheries management strategies. The model is multi-stock, multi-fleet, stochastic and seasonal. The fishery system is described as a sum of processes, which are internally assembled in a predetermined way. There are several functions available to describe the dynamic of each process and new functions can be added to satisfy specific requirements.

Restoring heart function and electrical integrity: closing the circuit

NASA Astrophysics Data System (ADS)

Monteiro, Luís Miguel; Vasques-Nóvoa, Francisco; Ferreira, Lino; Pinto-do-Ó, Perpétua; Nascimento, Diana Santos

2017-04-01

Cardiovascular diseases are the main cause of death in the world and are often associated with the occurrence of arrhythmias due to disruption of myocardial electrical integrity. Pathologies involving dysfunction of the specialized cardiac excitatory/conductive tissue are also common and constitute an added source of morbidity and mortality since current standard therapies withstand a great number of limitations. As electrical integrity is essential for a well-functioning heart, innovative strategies have been bioengineered to improve heart conduction and/or promote myocardial repair, based on: (1) gene and/or cell delivery; or (2) conductive biomaterials as tools for cardiac tissue engineering. Herein we aim to review the state-of-art in the area, while briefly describing the biological principles underlying the heart electrical/conduction system and how this system can be disrupted in heart disease. Suggestions regarding targets for future studies are also presented.

Comparative study of popular objective functions for damping power system oscillations in multimachine system.

PubMed

Islam, Naz Niamul; Hannan, M A; Shareef, Hussain; Mohamed, Azah; Salam, M A

2014-01-01

Power oscillation damping controller is designed in linearized model with heuristic optimization techniques. Selection of the objective function is very crucial for damping controller design by optimization algorithms. In this research, comparative analysis has been carried out to evaluate the effectiveness of popular objective functions used in power system oscillation damping. Two-stage lead-lag damping controller by means of power system stabilizers is optimized using differential search algorithm for different objective functions. Linearized model simulations are performed to compare the dominant mode's performance and then the nonlinear model is continued to evaluate the damping performance over power system oscillations. All the simulations are conducted in two-area four-machine power system to bring a detailed analysis. Investigated results proved that multiobjective D-shaped function is an effective objective function in terms of moving unstable and lightly damped electromechanical modes into stable region. Thus, D-shape function ultimately improves overall system damping and concurrently enhances power system reliability.

Estimation of runoff mitigation by morphologically different cover crop root systems

NASA Astrophysics Data System (ADS)

Yu, Yang; Loiskandl, Willibald; Kaul, Hans-Peter; Himmelbauer, Margarita; Wei, Wei; Chen, Liding; Bodner, Gernot

2016-07-01

Hydrology is a major driver of biogeochemical processes underlying the distinct productivity of different biomes, including agricultural plantations. Understanding factors governing water fluxes in soil is therefore a key target for hydrological management. Our aim was to investigate changes in soil hydraulic conductivity driven by morphologically different root systems of cover crops and their impact on surface runoff. Root systems of twelve cover crop species were characterized and the corresponding hydraulic conductivity was measured by tension infiltrometry. Relations of root traits to Gardner's hydraulic conductivity function were determined and the impact on surface runoff was estimated using HYDRUS 2D. The species differed in both rooting density and root axes thickness, with legumes distinguished by coarser axes. Soil hydraulic conductivity was changed particularly in the plant row where roots are concentrated. Specific root length and median root radius were the best predictors for hydraulic conductivity changes. For an intensive rainfall simulation scenario up to 17% less rainfall was lost by surface runoff in case of the coarsely rooted legumes Melilotus officinalis and Lathyrus sativus, and the densely rooted Linum usitatissimum. Cover crops with coarse root axes and high rooting density enhance soil hydraulic conductivity and effectively reduce surface runoff. An appropriate functional root description can contribute to targeted cover crop selection for efficient runoff mitigation.

Visualization of human heart conduction system by means of fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Venius, Jonas; Bagdonas, Saulius; Žurauskas, Edvardas; Rotomskis, Ricardas

2011-10-01

The conduction system of the heart is a specific muscular tissue, where a heartbeat signal originates and initiates the depolarization of the ventricles. The muscular origin makes it complicated to distinguish the conduction system from the surrounding tissues. A surgical intervention can lead to the accidental harm of the conduction system, which may eventually result in a dangerous obstruction of the heart functionality. Therefore, there is an immense necessity for developing a helpful method to visualize the conduction system during the operation time. The specimens for the spectroscopic studies were taken from nine diverse human hearts. The localization of distinct types of the tissue was preliminary marked by the pathologist and approved histologically after the spectral measurements. Variations in intensity, as well as in shape, were detected in autofluorescence spectra of different heart tissues. The most distinct differences were observed between the heart conduction system and the surrounding tissues under 330 and 380 nm excitation. The spectral region around 460 nm appeared to be the most suitable for an unambiguous differentiation of the human conduction system avoiding the absorption peak of blood. The visualization method, based on the intensity ratios calculated for two excitation wavelengths, was also demonstrated.

Measures of Autonomic Nervous System Regulation

DTIC Science & Technology

2011-04-01

and most often used measures of ANS activation encompass non-invasive tools, which measure cardiac, skin conductance, respiratory , and vascular...regulation, osmotic balance, metabolism, digestion, excretion, and cardiac and respiratory activity. The ANS consists of the sympathetic and...modulate heart rate, as a function of the respiratory cycles. Generally, these two systems should be seen as permanently modulating vital functions to

Experimental optimization of the FireFly 600 photovoltaic off-grid system.

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

Boyson, William Earl; Orozco, Ron; Ralph, Mark E.

2003-10-01

A comprehensive evaluation and experimental optimization of the FireFly{trademark} 600 off-grid photovoltaic system manufactured by Energia Total, Ltd. was conducted at Sandia National Laboratories in May and June of 2001. This evaluation was conducted at the request of the manufacturer and addressed performance of individual system components, overall system functionality and performance, safety concerns, and compliance with applicable codes and standards. A primary goal of the effort was to identify areas for improvement in performance, reliability, and safety. New system test procedures were developed during the effort.

Microscopic theoretical study of frequency dependent dielectric constant of heavy fermion systems

NASA Astrophysics Data System (ADS)

Shadangi, Keshab Chandra; Rout, G. C.

2017-05-01

The dielectric polarization and the dielectric constant plays a vital role in the deciding the properties of the Heavy Fermion Systems. In the present communication we consider the periodic Anderson's Model which consists of conduction electron kinetic energy, localized f-electron kinetic energy and the hybridization between the conduction and localized electrons, besides the Coulomb correlation energy. We calculate dielectric polarization which involves two particle Green's functions which are calculated by using Zubarev's Green's function technique. Using the equations of motion of the fermion electron operators. Finally, the temperature and frequency dependent dielectric constant is calculated from the dielectric polarization function. The charge susceptibility and dielectric constant are computed numerically for different physical parameters like the position (Ef) of the f-electron level with respect to fermi level, the strength of the hybridization (V) between the conduction and localized f-electrons, Coulomb correlation potential temperature and optical phonon wave vector (q). The results will be discussed in a reference to the experimental observations of the dielectric constants.

GW electronic Correlations in Quantum Transport : Renormalization and finite lifetime effects on real systems

NASA Astrophysics Data System (ADS)

Darancet, Pierre; Ferretti, Andrea; Mayou, Didier; Olevano, Valerio

2007-03-01

We present an ab initio approach to electronic transport in nanoscale systems which includes electronic correlations through the GW approximation. With respect to Landauer approaches based on density-functional theory (DFT), we introduce a physical quasiparticle electronic-structure into a non-equilibrium Green's function theory framework. We use an equilibrium non-selfconsistent G^0W^0 self-energy considering both full non-hermiticity and dynamical effects. The method is applied to a real system, a gold mono-atomic chain. With respect to DFT results, the conductance profile is modified and reduced by to the introduction of diffusion and loss-of-coherence effects. The linear response conductance characteristic appear to be in agreement with experimental results.

A Top Level Analysis of Training Management Functions.

ERIC Educational Resources Information Center

Ackerson, Jack

1995-01-01

Discusses how to conduct a top-level analysis of training management functions to identify problems within a training system resulting from rapid growth, the acquisition of new departments, or mergers. The data gathering process and analyses are explained, training management functions and activities are described, and root causes and solutions…

Vacuum distillation/vapor filtration water recovery

NASA Technical Reports Server (NTRS)

Honegger, R. J.; Neveril, R. B.; Remus, G. A.

1974-01-01

The development and evaluation of a vacuum distillation/vapor filtration (VD/VF) water recovery system are considered. As a functional model, the system converts urine and condensates waste water from six men to potable water on a steady-state basis. The system is designed for 180-day operating durations and for function on the ground, on zero-g aircraft, and in orbit. Preparatory tasks are summarized for conducting low gravity tests of a vacuum distillation/vapor filtration system for recovering water from urine.

Cystic Fibrosis and the Nervous System.

PubMed

Reznikov, Leah R

2017-05-01

Cystic fibrosis (CF) is a life-shortening autosomal recessive disorder caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR). CFTR is an anion channel that conducts bicarbonate and chloride across cell membranes. Although defective anion transport across epithelial cells is accepted as the basic defect in CF, many of the features observed in people with CF and organs affected by CF are modulated by the nervous system. This is of interest because CFTR expression has been reported in both the peripheral and central nervous systems, and it is well known that the transport of anions, such as chloride, greatly modulates neuronal excitability. Thus it is predicted that in CF, lack of CFTR in the nervous system affects neuronal function. Consistent with this prediction, several nervous system abnormalities and nervous system disorders have been described in people with CF and in animal models of CF. The goal of this special feature article is to highlight the expression and function of CFTR in the nervous system. Special emphasis is placed on nervous system abnormalities described in people with CF and in animal models of CF. Finally, features of CF that may be modulated by or attributed to faulty nervous system function are discussed. Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Analysis of UAS DAA Surveillance in Fast-Time Simulations without DAA Mitigation

NASA Technical Reports Server (NTRS)

Thipphavong, David P.; Santiago, Confesor; Isaacson, David R.; Lee, Seung Man; Refai, Mohamad Said; Snow, James William

2015-01-01

Realization of the expected proliferation of Unmanned Aircraft System (UAS) operations in the National Airspace System (NAS) depends on the development and validation of performance standards for UAS Detect and Avoid (DAA) Systems. The RTCA Special Committee 228 is charged with leading the development of draft Minimum Operational Performance Standards (MOPS) for UAS DAA Systems. NASA, as a participating member of RTCA SC-228 is committed to supporting the development and validation of draft requirements for DAA surveillance system performance. A recent study conducted using NASA's ACES (Airspace Concept Evaluation System) simulation capability begins to address questions surrounding the development of draft MOPS for DAA surveillance systems. ACES simulations were conducted to study the performance of sensor systems proposed by the SC-228 DAA Surveillance sub-group. Analysis included but was not limited to: 1) number of intruders (both IFR and VFR) detected by all sensors as a function of UAS flight time, 2) number of intruders (both IFR and VFR) detected by radar alone as a function of UAS flight time, and 3) number of VFR intruders detected by all sensors as a function of UAS flight time. The results will be used by SC-228 to inform decisions about the surveillance standards of UAS DAA systems and future requirements development and validation efforts.

Systemic Functional Linguistic Genre Pedagogy ((SFL GP) in a Tertiary EFL Writing Context in Indonesia

ERIC Educational Resources Information Center

Emilia, Emi; Hamied, Fuad Abdul

2015-01-01

This article reports on the results of a study aiming to investigate whether systemic functional linguistic genre pedagogy (SFL GP) can help students develop their writing ability in English and the students' opinions about the teaching program using SFL GP. The study was conducted in one semester with 19 student teachers taking a writing course…

Ablation of selected conducting layers by fiber laser

NASA Astrophysics Data System (ADS)

Pawlak, Ryszard; Tomczyk, Mariusz; Walczak, Maria

2014-08-01

Laser Direct Writing (LDW) are used in the manufacture of electronic circuits, pads, and paths in sub millimeter scale. They can also be used in the sensors systems. Ablative laser writing in a thin functional layer of material deposited on the dielectric substrate is one of the LDW methods. Nowadays functional conductive layers are composed from graphene paint or nanosilver paint, indium tin oxide (ITO), AgHTTM and layers containing carbon nanotubes. Creating conducting structures in transparent layers (ITO, AgHT and carbon nanotubes layers) may have special importance e.g. for flexi electronics. The paper presents research on the fabrication of systems of paths and appropriate pattern systems of paths and selected electronic circuits in AgHTTM and ITO layers deposited on glass and polymer substrates. An influence of parameters of ablative fiber laser treatment in nanosecond regime as well as an influence of scanning mode of laser beam on the pattern fidelity and on electrical parameters of a generated circuit was investigated.

Alterations in HPA-axis and autonomic nervous system functioning in childhood anxiety disorders point to a chronic stress hypothesis.

PubMed

Dieleman, Gwendolyn C; Huizink, Anja C; Tulen, Joke H M; Utens, Elisabeth M W J; Creemers, Hanneke E; van der Ende, Jan; Verhulst, Frank C

2015-01-01

It is of debate whether or not childhood anxiety disorders (AD) can be captured by one taxonomic construct. This study examined whether perceived arousal (PA), autonomic nervous system (ANS) and hypothalamic-pituitary-adrenal (HPA) axis measures can distinguish children with different primary diagnoses of clinical anxiety disorders (AD) from each other, and from a general population reference group (GP). The study sample consisted of 152 AD children (comparing separation anxiety disorder, generalized anxiety disorder, social phobia and specific phobia), aged 8- to 12-years, and 200 same-aged reference children. HPA-axis functioning was measured by a diurnal cortisol profile. ANS functioning was measured by continuous measures of skin conductance level in rest and during a mental arithmetic task and high frequency heart rate variability in rest. PA was assessed by a questionnaire. The AD sample showed lower high frequency heart rate variability during rest, heightened anticipatory PA, higher basal and reactive skin conductance levels and lower basal HPA-axis functioning compared to the GP sample. The existence of three or more clinical disorders, i.e. a high clinical 'load', was associated with lower basal HPA-axis functioning, higher skin conductance level and lower posttest PA. Specific phobia could be discerned from social phobia and separation anxiety disorder on higher skin conductance level. Our findings indicated that children with AD have specific psychophysiological characteristics, which resemble the psychophysiological characteristics of chronic stress. A high clinical 'load' is associated with an altered ANS and HPA-axis functioning. Overall, ANS and HPA-axis functioning relate to AD in general, accept for specific phobia. Copyright © 2014 Elsevier Ltd. All rights reserved.

Electron tunnelling into amorphous germanium and silicon.

NASA Technical Reports Server (NTRS)

Smith, C. W.; Clark, A. H.

1972-01-01

Measurements of tunnel conductance versus bias, capacitance versus bias, and internal photoemission were made in the systems aluminum-oxide-amorphous germanium and aluminium-oxide-amorphous silicon. A function was extracted which expresses the deviation of these systems from the aluminium-oxide-aluminium system.

Development and Testing of a USM High Altitude Balloon

NASA Astrophysics Data System (ADS)

Thaheer, A. S. Mohamed; Ismail, N. A.; Yusoff, S. H. Md.; Nasirudin, M. A.

2018-04-01

This paper discusses on tests conducted on the component and subsystem level during development of the USM High Altitude Balloon (HAB). The tests conducted by selecting initial components then tested individually based on several case studies such as reliability test, camera viewing, power consumption, thermal capability, and parachute performance. Then, the component is integrated into sub-system level for integration and functionality test. The preliminary result is utilized to tune the components and sub-systems and trial launch is conducted where the sample images are recorded and atmospheric data successfully collected.

Systems and methods for selective hydrogen transport and measurement

DOEpatents

Glatzmaier, Gregory C

2013-10-29

Systems and methods for selectively removing hydrogen gas from a hydrogen-containing fluid volume are disclosed. An exemplary system includes a proton exchange membrane (PEM) selectively permeable to hydrogen by exclusively conducting hydrogen ions. The system also includes metal deposited as layers onto opposite sides or faces of the PEM to form a membrane-electrode assembly (MEA), each layer functioning as an electrode so that the MEA functions as an electrochemical cell in which the ionic conductors are hydrogen ions, and the MEA functioning as a hydrogen selective membrane (HSM) when located at the boundary between a hydrogen-containing fluid volume and a second fluid.

Tuning the thermal conductance of molecular junctions with interference effects

NASA Astrophysics Data System (ADS)

Klöckner, J. C.; Cuevas, J. C.; Pauly, F.

2017-12-01

We present an ab initio study of the role of interference effects in the thermal conductance of single-molecule junctions. To be precise, using a first-principles transport method based on density functional theory, we analyze the coherent phonon transport in single-molecule junctions made of several benzene and oligo(phenylene ethynylene) derivatives. We show that the thermal conductance of these junctions can be tuned via the inclusion of substituents, which induces destructive interference effects and results in a decrease of the thermal conductance with respect to the unmodified molecules. In particular, we demonstrate that these interference effects manifest as antiresonances in the phonon transmission, whose energy positions can be tuned by varying the mass of the substituents. Our work provides clear strategies for the heat management in molecular junctions and, more generally, in nanostructured metal-organic hybrid systems, which are important to determine how these systems can function as efficient energy-conversion devices such as thermoelectric generators and refrigerators.

Utilizing an Energy Management System with Distributed Resources to Manage Critical Loads and Reduce Energy Costs

DTIC Science & Technology

2014-09-01

peak shaving, conducting power factor correction, matching critical load to most efficient distributed resource, and islanding a system during...photovoltaic arrays during islanding, and power factor correction, the implementation of the ESS by itself is likely to prove cost prohibitive. The DOD...These functions include peak shaving, conducting power factor correction, matching critical load to most efficient distributed resource, and islanding a

Individual Differences in Adolescents' Sympathetic and Parasympathetic Functioning Moderate Associations between Family Environment and Psychosocial Adjustment

ERIC Educational Resources Information Center

Diamond, Lisa M.; Fagundes, Christopher P.; Cribbet, Matthew R.

2012-01-01

The present study tested whether individual differences in autonomic nervous system functioning interact with environmental risk factors to predict adolescents' psychosocial functioning. The authors assessed skin conductance and respiratory sinus arrhythmia at rest and during laboratory stressors in 110 14-year-olds. Subsequently, adolescents and…

33 CFR 157.12f - Workshop functional test requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... CARRYING OIL IN BULK Design, Equipment, and Installation § 157.12f Workshop functional test requirements. (a) Each oil content meter and each control section of a monitoring system must be subjected to a... protocol must be received with each unit delivered. (b) A functional test conducted on an oil content meter...

33 CFR 157.12f - Workshop functional test requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... CARRYING OIL IN BULK Design, Equipment, and Installation § 157.12f Workshop functional test requirements. (a) Each oil content meter and each control section of a monitoring system must be subjected to a... protocol must be received with each unit delivered. (b) A functional test conducted on an oil content meter...

33 CFR 157.12f - Workshop functional test requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... CARRYING OIL IN BULK Design, Equipment, and Installation § 157.12f Workshop functional test requirements. (a) Each oil content meter and each control section of a monitoring system must be subjected to a... protocol must be received with each unit delivered. (b) A functional test conducted on an oil content meter...

Standardization of the Functional Assessment and Intervention Program (FAIP) with Children Who Have Externalizing Behaviors

ERIC Educational Resources Information Center

Hartwig, Laurie; Heathfield, Lora Tuesday; Jenson, William R.

2004-01-01

The purpose of this study was to develop standardization data for the Functional Assessment Intervention Program (FAIP; University of Utah, Utah State University, & Utah State Office of Education, 1999), a computerized, functional behavioral assessment expert system. Reliability, validity, and utility analyses were conducted with students serving…

75 FR 22846 - Petition for Modification

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-30

... establish the requirements and procedures for filing petitions for modification. II. Petition for... dust covers, weekly inspection and functional testing of the complete deluge-type water spray system...: (1) Weekly inspection and functional tests are conducted of its complete deluge- type water spray...

Conduct problems in youth and the RDoC approach: A developmental, evolutionary-based view.

PubMed

Fonagy, Peter; Luyten, Patrick

2017-09-08

Problems related to aggression in young people are traditionally subsumed under the header of conduct problems, which include conduct disorder and oppositional defiant disorder. Such problems in children and adolescents are an important societal and mental health problem. In this paper we present an evolutionarily informed developmental psychopathology view of conduct problems inspired by the NIMH Research Domain Criteria (RDoC) initiative. We assume that while there are many pathways to conduct problems, chronic or temporary impairments in the domain of social cognition or mentalizing are a common denominator. Specifically, we conceptualize conduct problems as reflecting temporary or chronic difficulties with mentalizing, that is, the capacity to understand the self and others in terms of intentional mental states, leading to a failure to inhibit interpersonal violence through a process of perspective-taking and empathy. These difficulties, in turn, stem from impairments in making use of a normally evolutionarily protected social learning system that functions to facilitate intergenerational knowledge transmission and protect social collaborative processes from impulsive and aggressive action. Temperamental, biological, and social risk factors in different combinations may all contribute to this outcome. This adaptation then interacts with impairments in other domains of functioning, such as in negative and positive valence systems and cognitive systems. This view highlights the importance of a complex interplay among biological, psychological, and environmental factors in understanding the origins of conduct problems. We outline the implications of these views for future research and intervention. Copyright © 2017 Elsevier Ltd. All rights reserved.

Space shuttle propulsion systems on-board checkout and monitoring system development study (extension). Volume 1: Summary and technical results

NASA Technical Reports Server (NTRS)

1972-01-01

An analysis was conducted of the space shuttle propulsion systems to define the onboard checkout and monitoring function. A baseline space shuttle vehicle and mission were used to establish the techniques and approach for defining the requirements. The requirements were analyzed to formulate criteria for implementing the functions of preflight checkout, performance monitoring, fault isolation, emergency detection, display, data storage, postflight evaluation, and maintenance retest.

Intermediate temperature proton conductors for PEM fuel cells based on phosphonic acid as protogenic group: a progress report.

PubMed

Steininger, H; Schuster, M; Kreuer, K D; Kaltbeitzel, A; Bingöl, B; Meyer, W H; Schauff, S; Brunklaus, G; Maier, J; Spiess, H W

2007-04-21

The melting behaviour and transport properties of straight chain alkanes mono- and difunctionalized with phosphonic acid groups have been investigated as a function of their length. The increase of melting temperature and decrease of proton conductivity with increasing chain length is suggested to be the consequence of an increasing ordering of the alkane segments which constrains the free aggregation of the phosphonic acid groups. However, the proton mobility is reduced to a greater extent than the proton diffusion coefficient indicating an increasing cooperativity of proton transport with increasing length of the alkane segment. The results clearly indicate that the "spacer concept", which had been proven successful in the optimization of the proton conductivity of heterocycle based systems, fails in the case of phosphonic acid functionalized polymers. Instead, a very high concentration of phosphonic acid functional groups forming "bulky" hydrogen bonded aggregates is suggested to be essential for obtaining very high proton conductivity. Aggregation is also suggested to reduce condensation reactions generally observed in phosphonic acid containing systems. On the basis of this understanding, the proton conductivities of poly(vinyl phosphonic acid) and poly(meta-phenylene phosphonic acid) are discussed. Though both polymers exhibit a substantial concentration of phosphonic acid groups, aggregation seems to be constrained to such an extent that intrinsic proton conductivity is limited to values below sigma = 10(-3) S cm(-1) at T = 150 degrees C. The results suggest that different immobilization concepts have to be developed in order to minimize the conductivity reduction compared to the very high intrinsic proton conductivity of neat phosphonic acid under quasi dry conditions. In the presence of high water activities, however, (as usually present in PEM fuel cells) the very high ion exchange capacities (IEC) possible for phosphonic acid functionalized ionomers (IEC >10 meq g(-1)) may allow for high proton conductivities in the intermediate temperature range (T approximately 120 -160 degrees C).

Implementation of a combined algorithm designed to increase the reliability of information systems: simulation modeling

NASA Astrophysics Data System (ADS)

Popov, A.; Zolotarev, V.; Bychkov, S.

2016-11-01

This paper examines the results of experimental studies of a previously submitted combined algorithm designed to increase the reliability of information systems. The data that illustrates the organization and conduct of the studies is provided. Within the framework of a comparison of As a part of the study conducted, the comparison of the experimental data of simulation modeling and the data of the functioning of the real information system was made. The hypothesis of the homogeneity of the logical structure of the information systems was formulated, thus enabling to reconfigure the algorithm presented, - more specifically, to transform it into the model for the analysis and prediction of arbitrary information systems. The results presented can be used for further research in this direction. The data of the opportunity to predict the functioning of the information systems can be used for strategic and economic planning. The algorithm can be used as a means for providing information security.

Study of Cs/NF3 adsorption on GaN (0 0 1) surface

NASA Astrophysics Data System (ADS)

Diao, Yu; Liu, Lei; Xia, Sihao; Kong, Yike

2017-03-01

To investigate the optoelectronics properties of Cs/NF3 adsorption on GaN (0 0 1) photocathode surface, different adsorption models of Cs-only, Cs/O, Cs/NF3 adsorption on GaN clean surface were established, respectively. Atomic structures, work function, adsorption energy, E-Mulliken charge distribution, density of states and optical properties of all these adsorption systems were calculated using first principles. Compared with Cs/O co-adsorption, Cs/NF3 co-adsorption show better stability and more decline of work function, which is more beneficial for photoemission efficiency. Besides, surface band structures of Cs/NF3 co-adsorption system exhibit metal properties, implying good conductivity. Meanwhile, near valence band minimum of Cs/NF3 co-adsorption system, more acceptor levels emerges to form a p-type emission surface, which is conductive to the escape of photoelectrons. In addition, imaginary part of dielectric function curve and absorption curve of Cs/NF3 co-adsorption system both move towards lower energy side. This work can direct the optimization of activation process of NEA GaN photocathode.

Using Form and Function Analogy Object Boxes to Teach Human Body Systems

ERIC Educational Resources Information Center

Rule, Audrey C.; Furletti, Charles

2004-01-01

This study compares the use of form and function analogy object boxes to more traditional lecture and worksheet instruction during a 10th-grade unit on human body systems. The study was conducted with two classes (N = 32) of mixed ability students at a high-needs rural high school in central New York State. The study used a pretest/posttest…

Study of space shuttle orbiter system management computer function. Volume 2: Automated performance verification concepts

NASA Technical Reports Server (NTRS)

1975-01-01

The findings are presented of investigations on concepts and techniques in automated performance verification. The investigations were conducted to provide additional insight into the design methodology and to develop a consolidated technology base from which to analyze performance verification design approaches. Other topics discussed include data smoothing, function selection, flow diagrams, data storage, and shuttle hydraulic systems.

Reusable Rocket Engine Advanced Health Management System. Architecture and Technology Evaluation: Summary

NASA Technical Reports Server (NTRS)

Pettit, C. D.; Barkhoudarian, S.; Daumann, A. G., Jr.; Provan, G. M.; ElFattah, Y. M.; Glover, D. E.

1999-01-01

In this study, we proposed an Advanced Health Management System (AHMS) functional architecture and conducted a technology assessment for liquid propellant rocket engine lifecycle health management. The purpose of the AHMS is to improve reusable rocket engine safety and to reduce between-flight maintenance. During the study, past and current reusable rocket engine health management-related projects were reviewed, data structures and health management processes of current rocket engine programs were assessed, and in-depth interviews with rocket engine lifecycle and system experts were conducted. A generic AHMS functional architecture, with primary focus on real-time health monitoring, was developed. Fourteen categories of technology tasks and development needs for implementation of the AHMS were identified, based on the functional architecture and our assessment of current rocket engine programs. Five key technology areas were recommended for immediate development, which (1) would provide immediate benefits to current engine programs, and (2) could be implemented with minimal impact on the current Space Shuttle Main Engine (SSME) and Reusable Launch Vehicle (RLV) engine controllers.

A Systems Engineering Approach to Architecture Development

NASA Technical Reports Server (NTRS)

Di Pietro, David A.

2014-01-01

Architecture development is conducted prior to system concept design when there is a need to determine the best-value mix of systems that works collectively in specific scenarios and time frames to accomplish a set of mission area objectives. While multiple architecture frameworks exist, they often require use of unique taxonomies and data structures. In contrast, this presentation characterizes architecture development using terminology widely understood within the systems engineering community. Using a notional civil space architecture example, it employs a multi-tier framework to describe the enterprise level architecture and illustrates how results of lower tier, mission area architectures integrate into the enterprise architecture. It also presents practices for conducting effective mission area architecture studies, including establishing the trade space, developing functions and metrics, evaluating the ability of potential design solutions to meet the required functions, and expediting study execution through the use of iterative design cycles.

A Systems Engineering Approach to Architecture Development

NASA Technical Reports Server (NTRS)

Di Pietro, David A.

2015-01-01

Architecture development is often conducted prior to system concept design when there is a need to determine the best-value mix of systems that works collectively in specific scenarios and time frames to accomplish a set of mission area objectives. While multiple architecture frameworks exist, they often require use of unique taxonomies and data structures. In contrast, this paper characterizes architecture development using terminology widely understood within the systems engineering community. Using a notional civil space architecture example, it employs a multi-tier framework to describe the enterprise level architecture and illustrates how results of lower tier, mission area architectures integrate into the enterprise architecture. It also presents practices for conducting effective mission area architecture studies, including establishing the trade space, developing functions and metrics, evaluating the ability of potential design solutions to meet the required functions, and expediting study execution through the use of iterative design cycles.

A Systems Engineering Approach to Architecture Development

NASA Technical Reports Server (NTRS)

Di Pietro, David A.

2015-01-01

Architecture development is often conducted prior to system concept design when there is a need to determine the best-value mix of systems that works collectively in specific scenarios and time frames to accomplish a set of mission area objectives. While multiple architecture frameworks exist, they often require use of unique taxonomies and data structures. In contrast, this paper characterizes architecture development using terminology widely understood within the systems engineering community. Using a notional civil space architecture example, it employs a multi-tier framework to describe the enterprise level architecture and illustrates how results of lower tier, mission area architectures integrate into the enterprise architecture. It also presents practices for conducting effective mission area architecture studies, including establishing the trade space, developing functions and metrics, evaluating the ability of potential design solutions to meet the required functions, and expediting study execution through the use of iterative design cycles

Reconstruction of Cell Surface Densities of Ion Pumps, Exchangers, and Channels from mRNA Expression, Conductance Kinetics, Whole-Cell Calcium, and Current-Clamp Voltage Recordings, with an Application to Human Uterine Smooth Muscle Cells

PubMed Central

Atia, Jolene; McCloskey, Conor; Shmygol, Anatoly S.; Rand, David A.; van den Berg, Hugo A.; Blanks, Andrew M.

2016-01-01

Uterine smooth muscle cells remain quiescent throughout most of gestation, only generating spontaneous action potentials immediately prior to, and during, labor. This study presents a method that combines transcriptomics with biophysical recordings to characterise the conductance repertoire of these cells, the ‘conductance repertoire’ being the total complement of ion channels and transporters expressed by an electrically active cell. Transcriptomic analysis provides a set of potential electrogenic entities, of which the conductance repertoire is a subset. Each entity within the conductance repertoire was modeled independently and its gating parameter values were fixed using the available biophysical data. The only remaining free parameters were the surface densities for each entity. We characterise the space of combinations of surface densities (density vectors) consistent with experimentally observed membrane potential and calcium waveforms. This yields insights on the functional redundancy of the system as well as its behavioral versatility. Our approach couples high-throughput transcriptomic data with physiological behaviors in health and disease, and provides a formal method to link genotype to phenotype in excitable systems. We accurately predict current densities and chart functional redundancy. For example, we find that to evoke the observed voltage waveform, the BK channel is functionally redundant whereas hERG is essential. Furthermore, our analysis suggests that activation of calcium-activated chloride conductances by intracellular calcium release is the key factor underlying spontaneous depolarisations. PMID:27105427

Method of measuring thermal conductivity of high performance insulation

NASA Technical Reports Server (NTRS)

Hyde, E. H.; Russell, L. D.

1968-01-01

Method accurately measures the thermal conductivity of high-performance sheet insulation as a discrete function of temperature. It permits measurements to be made at temperature drops of approximately 10 degrees F across the insulation and ensures measurement accuracy by minimizing longitudinal heat losses in the system.

Slower nerve conduction velocity in individuals with functional ankle instability.

PubMed

Simon, J; Docherty, C

2014-08-01

The purpose of this study is to quantify nerve conduction velocity differences in individuals with functional ankle instability compared to a "healthy" population. 38 participants ages 18-30 were recruited from a large university with approximately 43,000 students. 19 subjects (9 men and 10 women; age=21.0±1.4 years; height=172.0±9.3 cm; mass=74.4±1 2.4 kg) with symptoms of functional ankle instability were in the functional ankle instability group. 19 subjects (10 men, 9 women; age=22.0±2.6 years; height=169.8±9.1 cm; mass=69.0±14.8 kg) with "healthy" ankles were in the control group. Nerve conduction velocity was conducted using one trial at 2 different sites: posterior to the fibular head (fibular), and 10 cm superior/posterior of the first site (popliteal). Nerve conduction velocity (m/sec) was assessed using a SierraWave II system (Cadwell Laboratories; Kennewick, WA). A MANCOVA was performed on the two dependent variables (fibular and popliteal). Covariates included surface temperature of the leg, body mass index, and age. The independent variable was group (functional ankle instability and control). The effect of group was significantly related to nerve conduction velocity at the fibular site (F(1, 27) =16.49, p=0.01) and popliteal site (F(1, 27)=4.51, p=0.01), with responses significantly faster for individuals in the control group than the functional ankle instability group. These results indicate that patients with functional ankle instability might have damage to the peroneal nerve which results in slower peroneal nerve conduction velocity. © Georg Thieme Verlag KG Stuttgart · New York.

Clinical neurologic indices of toxicity in animals.

PubMed Central

O'Donoghue, J L

1996-01-01

The fundamental structures and functions of the nervous systems of animals and humans are conserved in many ways across species. These similarities provide a basis for developing common neurologic examinations for a number of species of animals and also provide a basis for developing risk assessments across species for neurologic end points. The neurologic examination requires no expensive equipment and can be conducted in the field or wherever impaired animals are identified. The proper conduct of neurologic examinations in animals assumes that the examiner has a fundamental understanding of the normal structure and function of the nervous system as well as knowledge about the spontaneous disease background of the species being studied. PMID:9182039

DFT-based ab initio MD simulation of the ionic conduction in doped ZrO₂ systems under epitaxial strain.

PubMed

Oka, M; Kamisaka, H; Fukumura, T; Hasegawa, T

2015-11-21

The oxygen ionic conduction in ZrO2 systems under tensile epitaxial strain was investigated by performing ab initio molecular dynamics (MD) calculations based on density functional theory (DFT) to elucidate the essential factors in the colossal ionic conductivity observed in the yttria stabilized ZrO2 (YSZ)/SrTiO3 heterostructure. Three factors were evaluated: lattice strain, oxygen vacancies, and dopants. Phonon calculations based on density functional perturbation theory (DFPT) were used to obtain the most stable structure for nondoped ZrO2 under 7% tensile strain along the a- and b-axes. This structure has the space group Pbcn, which is entirely different from that of cubic ZrO2, suggesting that previous ab initio MD calculations assuming cubic ZrO2 may have overestimated the ionic conductivity due to relaxation from the initial structure to the stable structure (Pbcn). Our MD calculations revealed that the ionic conductivity is enhanced only when tensile strain and oxygen vacancies are incorporated, although the presently obtained diffusion constant is far below the range for the colossal ionic conduction experimentally observed. The enhanced ionic conductivity is due to the combined effects of oxygen sublattice formation induced by strain and deformation of this sublattice by oxygen vacancies.

Navigation and Positioning System Using High Altitude Platforms Systems (HAPS)

NASA Astrophysics Data System (ADS)

Tsujii, Toshiaki; Harigae, Masatoshi; Harada, Masashi

Recently, some countries have begun conducting feasibility studies and R&D projects on High Altitude Platform Systems (HAPS). Japan has been investigating the use of an airship system that will function as a stratospheric platform for applications such as environmental monitoring, communications and broadcasting. If pseudolites were mounted on the airships, their GPS-like signals would be stable augmentations that would improve the accuracy, availability, and integrity of GPS-based positioning systems. Also, the sufficient number of HAPS can function as a positioning system independent of GPS. In this paper, a system design of the HAPS-based positioning system and its positioning error analyses are described.

Theoretical and Experimental Studies of Functionalized Carbon Nanotubes for Improved Thermal Conductivity

NASA Astrophysics Data System (ADS)

Kerr, Alexander; Burt, Timothy; Mullen, Kieran; Glatzhofer, Daniel; Houck, Matthew; Huang, Paul

The use of carbon nanotubes (CNTs) to improve the thermal conductivity of composite materials is thwarted by their large thermal boundary resistance. We study how to overcome this Kapitza resistance by functionalizing CNTs with mixed molecular chains. Certain configurations of chains improve the transmission of thermal vibrations through our systems by decreasing phonon mismatch between the CNTs and their surrounding matrix. Through the calculation of vibrational normal modes and Green's functions, we develop a variety of computational metrics to compare the thermal conductivity (κ) of our systems. We show how different configurations of attached chains affect the samples' κ values by varying chain identity, chain length, number of chains, and heat driver behavior. We vary the parameters to maximize κ. To validate and optimize these metrics, we perform molecular dynamics simulations for comparison. We also present experimental results of composites enhanced with CNTs and make comparisons to the theory. We observe that some composites are thermally improved with the inclusion of CNTs, while others are scarcely changed, in agreement with theoretical models. This work was supported by NSF Grant DMR-1310407.

NHTSA's heavy duty vehicle brake research program report number 11 : evaluation of stopping performance of trailer antilock brake systems

DOT National Transportation Integrated Search

1997-04-01

In order to better understand the functioning of antilock brake systems on pneumatically braked trailers, a series of tests were conducted to evaluate different ABS control strategies, performance variations among systems supplied by different manufa...

Density of states and extent of wave function: two crucial factors for small polaron hopping conductivity in 1D

NASA Astrophysics Data System (ADS)

Dimakogianni, M.; Simserides, C.; Triberis, G. P.

2013-07-01

We introduce a theoretical model to scrutinize the conductivity of small polarons in 1D disordered systems, focusing on two crucial - as will be demonstrated - factors: the density of states and the spatial extent of the electronic wave function. The investigation is performed for any temperature up to 300 K and under electric field of arbitrary strength up to the polaron dissociation limit. To accomplish this task, we combine analytical work with numerical calculations.

2015 Summer Series - Lee Stone - Brain Function Through the Eyes of the Beholder

NASA Image and Video Library

2015-06-09

The Visuomotor Control Laboratory (VCL) at NASA Ames conducts neuroscience research on the link between eye movements and brain function to provide an efficient and quantitative means of monitoring human perceptual performance. The VCL aims to make dramatic improvements in mission success through analysis, experimentation, and modeling of human performance and human-automation interaction. Dr. Lee Stone elaborates on how this research is conducted and how it contributes to NASA's mission and advances human-centered design and operations of complex aerospace systems.

Improvement of thermal conductivities for silicone nanocomposite via incorporating poly(γ-methacryloxypropyltrimethoxy silane) grafted graphene fillers

NASA Astrophysics Data System (ADS)

Chen, Tian; Liu, Bo

2018-02-01

The proposed grafting polymerization of γ-methacryloxypropyltrimethoxy silane was performed to functionalize graphene, aiming to fabricate functionalized graphene/silicone with excellent thermal conductivities. The surface morphology and element content of poly(γ-methacryloxypropyltrimethoxy silane) grafted reduced graphene oxide (g-RGO) was characterized by Atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS). The usage of g-RGO was benefit for improving the thermal conductivity of silicone (SI). The g-RGO/SI (2 wt% filler) had thermal conductivity of 1.31 W·m-1·K-1 and thermal diffusivity of 1.08 mm2·s-1 (increased by 620% compared to that of SI), which held potential for electronic packaging materials and micro-electro-mechanical systems apparatus.

Magnetic-field-induced mixed-level Kondo effect in two-level systems

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

Wong, Arturo; Ngo, Anh T.; Ulloa, Sergio E.

2016-10-17

We consider a two-orbital impurity system with intra-and interlevel Coulomb repulsion that is coupled to a single conduction channel. This situation can generically occur in multilevel quantum dots or in systems of coupled quantum dots. For finite energy spacing between spin-degenerate orbitals, an in-plane magnetic field drives the system from a local-singlet ground state to a "mixed-level" Kondo regime, where the Zeeman-split levels are degenerate for opposite-spin states. We use the numerical renormalization group approach to fully characterize this mixed-level Kondo state and discuss its properties in terms of the applied Zeeman field, temperature, and system parameters. Under suitable conditions,more » the total spectral function is shown to develop a Fermi-level resonance, so that the linear conductance of the system peaks at a finite Zeeman field while it decreases as a function of temperature. These features, as well as the local moment and entropy contribution of the impurity system, are commensurate with Kondo physics, which can be studied in suitably tuned quantum dot systems.« less

Performance Evaluation of an Oxygen Sensor as a Function of the Samaria Doped Ceria Film Thickness

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

Sanghavi, Rahul P.; Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana V N T

The current demand in the automobile industry is in the control of air-fuel mixture in the combustion engine of automobiles. Oxygen partial pressure can be used as an input parameter for regulating or controlling systems in order to optimize the combustion process. Our goal is to identify and optimize the material system that would potentially function as the active sensing material for such a device that monitors oxygen partial pressure in these systems. We have used thin film samaria doped ceria (SDC) as the sensing material for the sensor operation, exploiting the fact that at high temperatures, oxygen vacancies generatedmore » due to samarium doping act as conducting medium for oxygen ions which hop through the vacancies from one side to the other contributing to an electrical signal. We have recently established that 6 atom % Sm doping in ceria films has optimum conductivity. Based on this observation, we have studied the variation in the overall conductivity of 6 atom % samaria doped ceria thin films as a function of thickness in the range of 50 nm to 300 nm at a fixed bias voltage of 2 volts. A direct proportionality in the increase in the overall conductivity is observed with the increase in sensing film thickness. For a range of oxygen pressure values from 1 mTorr to 100 Torr, a tolerable hysteresis error, good dynamic response and a response time of less than 10 seconds was observed« less

Executive Function Mechanisms of Theory of Mind

ERIC Educational Resources Information Center

Ahmed, Fayeza S.; Miller, L. Stephen

2011-01-01

This study examined the relationship between Executive Function (EF) and Theory of Mind (ToM) using the Delis-Kaplan Executive Function System (D-KEFS) and three tests of ToM (Reading the Mind in the Eyes test (RMET), Strange Stories test, and Faux Pas test). Separate regression analyses were conducted, and EF predictors varied by ToM test. No EF…

Specialized impulse conduction pathway in the alligator heart

PubMed Central

Crossley, Dane A; Conner, Justin; Mohan, Rajiv A; van Duijvenboden, Karel; Postma, Alex V; Gloschat, Christopher R; Elsey, Ruth M; Sedmera, David; Efimov, Igor R

2018-01-01

Mammals and birds have a specialized cardiac atrioventricular conduction system enabling rapid activation of both ventricles. This system may have evolved together with high heart rates to support their endothermic state (warm-bloodedness) and is seemingly lacking in ectothermic vertebrates from which first mammals then birds independently evolved. Here, we studied the conduction system in crocodiles (Alligator mississippiensis), the only ectothermic vertebrates with a full ventricular septum. We identified homologues of mammalian conduction system markers (Tbx3-Tbx5, Scn5a, Gja5, Nppa-Nppb) and show the presence of a functional atrioventricular bundle. The ventricular Purkinje network, however, was absent and slow ventricular conduction relied on trabecular myocardium, as it does in other ectothermic vertebrates. We propose the evolution of the atrioventricular bundle followed full ventricular septum formation prior to the development of high heart rates and endothermy. In contrast, the evolution of the ventricular Purkinje network is strongly associated with high heart rates and endothermy. PMID:29565246

Integration of pyrotechnics into aerospace systems

NASA Technical Reports Server (NTRS)

Bement, Laurence J.; Schimmel, Morry L.

1993-01-01

The application of pyrotechnics to aerospace systems has been resisted because normal engineering methods cannot be used in design and evaluation. Commonly used approaches for energy sources, such as electrical, hydraulic and pneumatic, do not apply to explosive and pyrotechnic devices. This paper introduces the unique characteristics of pyrotechnic devices, describes how functional evaluations can be conducted, and demonstrates an engineering approach for pyrotechnic integration. Logic is presented that allows evaluation of two basic types of pyrotechnic systems to demonstrate functional margin.

Defense Primer: The National Defense Budget Function (050)

DTIC Science & Technology

2017-03-17

in parenthesis). This defense primer addresses the National Defense Budget (050), which is frequently used to explain trends in military spending...but which also includes some activities not conducted by the Department of Defense. What Is the Purpose of the Budget Function System? The budget

76 FR 77840 - Statement of Organization, Functions and Delegations of Authority

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-14

... current liaison functions and grant policy processes within the Office of Federal Assistance Management... processes related to assistance programs; (3) facilitates, plans, directs and coordinates the administration... review of grant applicants' and grantees' accounting systems; (5) conducts ad hoc studies and reviews...

Spin-Controlled Conductivity in a Thiophene-Functionalized Iron-Bis(dicarbollide)

NASA Astrophysics Data System (ADS)

Beach, Benjamin; Sauriol, Dustin; Derosa, Pedro

2016-04-01

The relationship between spin state and conductivity is studied for a thiophene-functionalized iron(III)-bis(dicarbollide) with one or two thiophenes at each end of the cage. Iron has a high ground state spin that can be adjusted by external electromagnetic fields to produce different magnetic states. The hypothesis explored here is that changes in the spin state of these Fe-containing molecules can lead to significant changes in molecular conductivity. Two examples of the possible application of such spin-dependent conductivity are its use as a molecular switch, the basic building block in digital logic, or as a memory bit. The molecules were first optimized using the Becke-3 Lee-Yang-Parr functional (B3LYP) with the 6-31G(d) basis set. A relaxed molecular geometry at each spin state was then placed between gold electrodes to conduct spin-polarized electron transport calculations with the density functional theory/non-equilibrium Green's functions formalism. The revised Perdew-Burke-Ernzerhf solids exchange-correlation functional (PBES) with double zeta polarized basis set was used. The result of these calculations show that the conductivity increases with the spin state. The cage structure is shown to exhibit fully delocalized molecular orbitals (MOs) appropriate for high conductivity and thus, in this system, the conductivity depends on the position of the MOs relative to the Fermi level. Minority spins are responsible for the conductivity of the doublet spin state while majority spins dominate for the quartet and sextet spin states as they are found closer to the Fermi level when they are occupied. Energy calculations predict a difference in energy between the more and the less conductive spin states (sextet and doublet respectively) that is 15-20 times greater than the thermal energy, which would imply stability at room temperature; however, the energy difference is sufficiently small that transitions between spin states can be induced.

Identification of high-level functional/system requirements for future civil transports

NASA Technical Reports Server (NTRS)

Swink, Jay R.; Goins, Richard T.

1992-01-01

In order to accommodate the rapid growth in commercial aviation throughout the remainder of this century, the Federal Aviation Administration (FAA) is faced with a formidable challenge to upgrade and/or modernize the National Airspace System (NAS) without compromising safety or efficiency. A recurring theme in both the Aviation System Capital Investment Plan (CIP), which has replaced the NAS Plan, and the new FAA Plan for Research, Engineering, and Development (RE&D) rely on the application of new technologies and a greater use of automation. Identifying the high-level functional and system impacts of such modernization efforts on future civil transport operational requirements, particularly in terms of cockpit functionality and information transfer, was the primary objective of this project. The FAA planning documents for the NAS of the 2005 era and beyond were surveyed; major aircraft functional capabilities and system components required for such an operating environment were identified. A hierarchical structured analysis of the information processing and flows emanating from such functional/system components were conducted and the results documented in graphical form depicting the relationships between functions and systems.

An antilock molecular braking system.

PubMed

Sun, Wei-Ting; Huang, Shou-Ling; Yao, Hsuan-Hsiao; Chen, I-Chia; Lin, Ying-Chih; Yang, Jye-Shane

2012-08-17

A light-driven molecular brake displaying an antilock function is constructed by introducing a nonradiative photoinduced electron transfer (PET) decay channel to compete with the trans (brake-off) → cis (brake-on) photoisomerization. A fast release of the brake can be achieved by deactivating the PET process through addition of protons. The cycle of irradiation-protonation-irradiation-deprotonation conducts the brake function and mimics the antilock braking system (ABS) of vehicles.

[Biotechnological functional systems].

PubMed

Bokser, O Ia

1999-01-01

Based on the theory of functional systems and a concept of the quantum system of behavior, studies of the quantumsystems were conducted. Their structure, the interaction of biological and technical sections were analyzed. Mathematical, biophysical, and experimental models were designed. The paper shows that biotechnical quantumsystems are involved in the formation of biological feedback. A system with imperative feedback from the programmed and introduced current results of efforts has been developed and put into practice for the self-regulation of muscle tension. Training by using this biological feedback system causes a stable increase in the perception rate of proprioceptive stimulus in examinees (operates, sportsmen, neurological patients).

Technical and Economic Feasibility Study of At-Grade Concrete Slab Track for Urban Rail Transit Systems

DOT National Transportation Integrated Search

1981-08-01

The report presents work conducted to evaluate the technical and economic feasibility of using concrete slab track systems for at-grade transit track. The functions of a rail transit track system are to guide railway vehicles and provide a safe and a...

The medical story. [Skylab program

NASA Technical Reports Server (NTRS)

Johnston, R. S.; Dietlein, L. F.; Michel, E. L.

1974-01-01

An overview of the Skylab medical program is given. All medical subsystems provided in the orbital workshop functioned satisfactorily. Major systems included the food system, the waste management system, and provisions per personal hygiene. A series of lockers in the wardroom was used to stow the inflight medical support system. Cardiovascular counter pressure garments were launched in the orbital workshop for all three crews. Life services experiments were carried out. Two experiments were conducted in the Skylab missions to study the performance of the cardiovascular system during weightless flight and return to earth and the one g environment. A series of experiments was conducted to study mineral balance and the bioassay of body fluids.

Organic/inorganic hybrid synaptic transistors gated by proton conducting methylcellulose films

NASA Astrophysics Data System (ADS)

Wan, Chang Jin; Zhu, Li Qiang; Wan, Xiang; Shi, Yi; Wan, Qing

2016-01-01

The idea of building a brain-inspired cognitive system has been around for several decades. Recently, electric-double-layer transistors gated by ion conducting electrolytes were reported as the promising candidates for synaptic electronics and neuromorphic system. In this letter, indium-zinc-oxide transistors gated by proton conducting methylcellulose electrolyte films were experimentally demonstrated with synaptic plasticity including paired-pulse facilitation and spatiotemporal-correlated dynamic logic. More importantly, a model based on proton-related electric-double-layer modulation and stretched-exponential decay function was proposed, and the theoretical results are in good agreement with the experimentally measured synaptic behaviors.

Organic/inorganic hybrid synaptic transistors gated by proton conducting methylcellulose films

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

Wan, Chang Jin; Wan, Qing, E-mail: wanqing@nju.edu.cn, E-mail: yshi@nju.edu.cn; Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201

The idea of building a brain-inspired cognitive system has been around for several decades. Recently, electric-double-layer transistors gated by ion conducting electrolytes were reported as the promising candidates for synaptic electronics and neuromorphic system. In this letter, indium-zinc-oxide transistors gated by proton conducting methylcellulose electrolyte films were experimentally demonstrated with synaptic plasticity including paired-pulse facilitation and spatiotemporal-correlated dynamic logic. More importantly, a model based on proton-related electric-double-layer modulation and stretched-exponential decay function was proposed, and the theoretical results are in good agreement with the experimentally measured synaptic behaviors.

Computing Legacy Software Behavior to Understand Functionality and Security Properties: An IBM/370 Demonstration

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

Linger, Richard C; Pleszkoch, Mark G; Prowell, Stacy J

Organizations maintaining mainframe legacy software can benefit from code modernization and incorporation of security capabilities to address the current threat environment. Oak Ridge National Laboratory is developing the Hyperion system to compute the behavior of software as a means to gain understanding of software functionality and security properties. Computation of functionality is critical to revealing security attributes, which are in fact specialized functional behaviors of software. Oak Ridge is collaborating with MITRE Corporation to conduct a demonstration project to compute behavior of legacy IBM Assembly Language code for a federal agency. The ultimate goal is to understand functionality and securitymore » vulnerabilities as a basis for code modernization. This paper reports on the first phase, to define functional semantics for IBM Assembly instructions and conduct behavior computation experiments.« less

Effect of asymmetric concentration profile on thermal conductivity in Ge/SiGe superlattices

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

Hahn, Konstanze R., E-mail: konstanze.hahn@dsf.unica.it; Cecchi, Stefano; Colombo, Luciano

2016-05-16

The effect of the chemical composition in Si/Ge-based superlattices on their thermal conductivity has been investigated using molecular dynamics simulations. Simulation cells of Ge/SiGe superlattices have been generated with different concentration profiles such that the Si concentration follows a step-like, a tooth-saw, a Gaussian, and a gamma-type function in direction of the heat flux. The step-like and tooth-saw profiles mimic ideally sharp interfaces, whereas Gaussian and gamma-type profiles are smooth functions imitating atomic diffusion at the interface as obtained experimentally. Symmetry effects have been investigated comparing the symmetric profiles of the step-like and the Gaussian function to the asymmetric profilesmore » of the tooth-saw and the gamma-type function. At longer sample length and similar degree of interdiffusion, the thermal conductivity is found to be lower in asymmetric profiles. Furthermore, it is found that with smooth concentration profiles where atomic diffusion at the interface takes place the thermal conductivity is higher compared to systems with atomically sharp concentration profiles.« less

DEVELOPMENTAL EFFECTS OF DIETARY SOY PHYTOESTROGENS

EPA Science Inventory

The purpose of the project is to conduct a series of experiments to determine whether developmental exposure to dietary phytochemicals that have estrogenic activity will affect central nervous system and reproductive system functions later in life. The basic design is, in additio...

Synthesis, structure, and ionic conductivity of solid solution, Li10+δM1+δP2-δS12 (M = Si, Sn).

PubMed

Hori, Satoshi; Suzuki, Kota; Hirayama, Masaaki; Kato, Yuki; Saito, Toshiya; Yonemura, Masao; Kanno, Ryoji

2014-01-01

Solid solutions of the silicon and tin analogous phases of the superionic conductor Li(10)MP(2)S(12) (M = Si, Sn) were synthesized by a conventional solid-state reaction in an evacuated silica tube at 823 K. The ranges of the solid solutions were determined to be 0.20 < δ < 0.43 and -0.25 < δ < -0.01 in Li(10+δ)M(1+δ)P(2-δ)S(12) (0.525 ≤k≤ 0.60 and 0.67 ≤k≤ 0.75 in Li(4-k)M(1-k)PkS(4)) for the Si and Sn systems, respectively. The ionic conductivity of these systems varied as a function of the changing M ions: the Si and Sn systems showed lower conductivity than the Ge system, Li(10+δ)Ge(1+δ)P(2-δ)S(12). The conductivity change for different elements might be due to the lattice size and lithium content affecting the ionic conduction. The relationship between ionic conduction, structure, and lithium concentration is discussed based on the structural and electrochemical information for the silicon, germanium, and tin systems.

Temperature dependency of the thermal conductivity of porous heat storage media

NASA Astrophysics Data System (ADS)

Hailemariam, Henok; Wuttke, Frank

2018-04-01

Analyzing the variation of thermal conductivity with temperature is vital in the design and assessment of the efficiency of sensible heat storage systems. In this study, the temperature variation of the thermal conductivity of a commercial cement-based porous heat storage material named - Füllbinder L is analyzed in saturated condition in the temperature range between 20 to 70°C (water based storage) with a steady state thermal conductivity and diffusivity meter. A considerable decrease in the thermal conductivity of the saturated sensible heat storage material upon increase in temperature is obtained, resulting in a significant loss of system efficiency and slower loading/un-loading rates, which when unaccounted for can lead to the under-designing of such systems. Furthermore, a new empirical prediction model for the estimation of thermal conductivity of cement-based porous sensible heat storage materials and naturally occurring crystalline rock formations as a function of temperature is proposed. The results of the model prediction are compared with the experimental results with satisfactory results.

Many-Body Spectral Functions from Steady State Density Functional Theory.

PubMed

Jacob, David; Kurth, Stefan

2018-03-14

We propose a scheme to extract the many-body spectral function of an interacting many-electron system from an equilibrium density functional theory (DFT) calculation. To this end we devise an ideal scanning tunneling microscope (STM) setup and employ the recently proposed steady-state DFT formalism (i-DFT) which allows one to calculate the steady current through a nanoscopic region coupled to two biased electrodes. In our setup, one of the electrodes serves as a probe ("STM tip"), which is weakly coupled to the system we want to measure. In the ideal STM limit of vanishing coupling to the tip, the system is restored to quasi-equilibrium and the normalized differential conductance yields the exact equilibrium many-body spectral function. Calculating this quantity from i-DFT, we derive an exact relation expressing the interacting spectral function in terms of the Kohn-Sham one. As illustrative examples, we apply our scheme to calculate the spectral functions of two nontrivial model systems, namely the single Anderson impurity model and the Constant Interaction Model.

Building a reference functional model for EHR systems.

PubMed

Sumita, Yuki; Takata, Mami; Ishitsuka, Keiju; Tominaga, Yasuyuki; Ohe, Kazuhiko

2007-09-01

Our aim was to develop a reference functional model for electric health record systems (RFM). Such a RFM is built from functions using functional descriptive elements (FDEs) and represents the static relationships between them. This paper presents a new format for describing electric health record (EHR) system functions. Questionnaire and field interview survey was conducted in five hospitals in Japan and one in the USA, to collect data on EHR system functions. Based on survey results, a reference functional list (RFL) was created, in which each EHR system function was listed and divided into 13 FDE types. By analyzing the RFL, we built the meta-functional model and the functional model using UML class diagrams. The former defines language for expressing the functional model, while the latter represents functions, FDEs and their static relationships. A total of 385 functions were represented in the RFL. Six patterns were found for the relationships between functions. The meta-functional model was created as a new format for describing functions. Examples of the functional model, which included the six patterns in the relationships between functions and 11 verbs, were created. We present the meta-functional model, which is a new description format for the functional structure and relationships. Although a more detailed description is required to apply the RFM to the semiautomatic generation of functional specification documents, our RFM can visualize functional structures and functional relationships, classify functions using multiple axes and identify the similarities and differences between functions. The RFM will promote not only the standardization of EHR systems, but also communications between system developers and healthcare providers in the EHR system-design processes. 2006 Elsevier Ireland Ltd

Networking the Home and University: How Families Can Be Integrated into Proximate/Distant Computer Systems.

ERIC Educational Resources Information Center

Watson, J. Allen; And Others

1989-01-01

Describes study that was conducted to determine the feasibility of networking home microcomputers with a university mainframe system in order to investigate a new family process research paradigm, as well as the design and function of the microcomputer/mainframe system. Test instrumentation is described and systems' reliability and validity are…

Thermal transport through a spin-phonon interacting junction: A nonequilibrium Green's function method study

NASA Astrophysics Data System (ADS)

Zhang, Zu-Quan; Lü, Jing-Tao

2017-09-01

Using the nonequilibrium Green's function method, we consider heat transport in an insulating ferromagnetic spin chain model with spin-phonon interaction under an external magnetic field. Employing the Holstein-Primakoff transformation to the spin system, we treat the resulted magnon-phonon interaction within the self-consistent Born approximation. We find the magnon-phonon coupling can change qualitatively the magnon thermal conductance in the high-temperature regime. At a spectral mismatched ferromagnetic-normal insulator interface, we also find thermal rectification and negative differential thermal conductance due to the magnon-phonon interaction. We show that these effects can be effectively tuned by the external applied magnetic field, a convenient advantage absent in anharmonic phonon and electron-phonon systems studied before.

Occupational Safety and Health System for Workers Engaged in Emergency Response Operations in the USA.

PubMed

Toyoda, Hiroyuki; Kubo, Tatsuhiko; Mori, Koji

2016-12-03

To study the occupational safety and health systems used for emergency response workers in the USA, we performed interviews with related federal agencies and conducted research on related studies. We visited the Federal Emergency Management Agency (FEMA) and National Institute for Occupational Safety and Health (NIOSH) in the USA and performed interviews with their managers on the agencies' roles in the national emergency response system. We also obtained information prepared for our visit from the USA's Occupational Safety and Health Administration (OSHA). In addition, we conducted research on related studies and information on the website of the agencies. We found that the USA had an established emergency response system based on their National Incident Management System (NIMS). This enabled several organizations to respond to emergencies cooperatively using a National Response Framework (NRF) that clarifies the roles and cooperative functions of each federal agency. The core system in NIMS was the Incident Command System (ICS), within which a Safety Officer was positioned as one of the command staff supporting the commander. All ICS staff were required to complete a training program specific to their position; in addition, the Safety Officer was required to have experience. The All-Hazards model was commonly used in the emergency response system. We found that FEMA coordinated support functions, and OSHA and NIOSH, which had specific functions to protect workers, worked cooperatively under NRF. These agencies employed certified industrial hygienists that play a professional role in safety and health. NIOSH recently executed support activities during disasters and other emergencies. The USA's emergency response system is characterized by functions that protect the lives and health of emergency response workers. Trained and experienced human resources support system effectiveness. The findings provided valuable information that could be used to improve the occupational safety and health function in the Japanese system.

Single molecule conductivity: the role of junction-orbital degeneracy in the artificially high currents predicted by ab initio approaches.

PubMed

Solomon, Gemma C; Reimers, Jeffrey R; Hush, Noel S

2004-10-08

A priori evaluations, using Hartree-Fock self-consistent-field (SCF) theory or density-functional theory (DFT), of the current passing between two electrodes through a single bridging molecule result in predicted conductivities that may be up to one to two orders of magnitude larger than observed ones. We demonstrate that this is, in part, often due to the improper application of the computational methods. Conductivity is shown to arise from tunneling between junction states of the electrodes through the molecule; these states are inherently either quasi two-fold or four-fold degenerate and always comprise the (highest occupied molecular orbital) HOMO band at the Fermi energy of the system. Frequently, in previous cluster based molecular conduction calculations, closed-shell SCF or Kohn-Sham DFT methods have been applied to systems that we demonstrate to be intrinsically open shell in nature. Such calculations are shown to induce artificial HOMO-LUMO (LUMO-lowest unoccupied molecular orbital) band splittings that Landauer-based formalisms for steady-state conduction interpret as arising from extremely rapid through-molecule tunneling at the Fermi energy, hence, overestimating the low-voltage conductivity. It is demonstrated that these shortcomings can be eliminated, dramatically reducing calculated current magnitudes, through the alternate use of electronic-structure calculations based on the spin-restricted open-shell formalism and related multiconfigurational SCF of DFT approaches. Further, we demonstrate that most anomalies arising in DFT implementations arise through the use of hybrid density functionals such as B3LYP. While the enhanced band-gap properties of these functionals have made them the defacto standard in molecular conductivity calculations, we demonstrate that it also makes them particularly susceptible to open-shell anomalies.

14 CFR Appendix E to Part 60 - Qualification Performance Standards for Quality Management Systems for Flight Simulation Training...

Code of Federal Regulations, 2011 CFR

2011-01-01

... conducted more frequently if warranted. End QPS Requirements Begin Information g. An example of a segment..., scheduling and conducting tests or inspections, functional preflight checks) but retain the responsibility... following: (a) A maintenance facility that provides suitable FSTD hardware and software tests and...

14 CFR Appendix E to Part 60 - Qualification Performance Standards for Quality Management Systems for Flight Simulation Training...

Code of Federal Regulations, 2013 CFR

2013-01-01

... conducted more frequently if warranted. End QPS Requirements Begin Information g. An example of a segment..., scheduling and conducting tests or inspections, functional preflight checks) but retain the responsibility... following: (a) A maintenance facility that provides suitable FSTD hardware and software tests and...

Functional and Multifunctional Polymers: Materials for Smart Structures

NASA Technical Reports Server (NTRS)

Arnold, S.; Pratt, L. M.; Li, J.; Wuagaman, M.; Khan, I. M.

1996-01-01

The ultimate goal of the research in smart structures and smart materials is the development of a new generation of products/devices which will perform better than products/devices built from passive materials. There are a few examples of multilayer polymer systems which function as smart structures, e.g. a synthetic muscle which is a multilayer assembly of a poly(ethylene) layer, a gold layer, and a poly(pyrrole) layer immersed in a liquid electrolyte. Oxidation and reductions of the active pyrrole layer causes the assembly to reversibly deflect and mimic biological muscles. The drawback of such a setup is slow response times and the use of a liquid electrolyte. We have developed multifunctional polymers which will eliminate the use of a liquid electrolyte, and also because the functionalities of the polymers are within a few hundred angstroms, an improved response time to changes in the external field should be possible. Such multifunctional polymers may be classified as the futuristic 'smart materials.' These materials are composed of a number of different functionalities which work in a synergistic fashion to function as a device. The device performs on the application of an external field and such multifunctional polymers may be scientifically labeled as 'field responsive polymers.' Our group has undertaken a systematic approach to develop functional and multifunctional polymers capable of functioning as field responsive polymers. Our approach utilizes multicomponent polymer systems (block copolymers and graft copolymers), the strategy involves the preparation of block or graft copolymers where the functionalities are limited to different phases in a microphase separated system. Depending on the weight (or volume) fractions of each of the components, different microstructures are possible. And, because of the intimate contact between the functional components, an increase in the synergism between the functionalities may be observed. In this presentation, three examples of multifunctional polymers developed in our labs will be reported. The first class of multifunctional polymers are the microphase separated mixed (ionic and electronic) conducting or MIEC block copolymers. The second class being developed in our labs are the biocompatible conductive materials and the conductive fluids. The final class may be considered microwave active smart polymers.

Holographic DC conductivity and Onsager relations

NASA Astrophysics Data System (ADS)

Donos, Aristomenis; Gauntlett, Jerome P.; Griffin, Tom; Lohitsiri, Nakarin; Melgar, Luis

2017-07-01

Within holography the DC conductivity can be obtained by solving a system of Stokes equations for an auxiliary fluid living on the black hole horizon. We show that these equations can be derived from a novel variational principle involving a functional that depends on the fluid variables of interest as well as the time reversed quantities. This leads to simple derivation of the Onsager relations for the conductivity. We also obtain the relevant Stokes equations for bulk theories of gravity in four dimensions including a ϑF ∧ F term in the Lagrangian, where ϑ is a function of dynamical scalar fields. We discuss various realisations of the anomalous Hall conductivity that this term induces and also solve the Stokes equations for holographic lattices which break translations in one spatial dimension.

Foundational Report Series: Advanced Distribution Management Systems for Grid Modernization, DMS Industry Survey

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

Singh, Ravindra; Uluski, Robert; Reilly, James T.

The objective of this survey is to benchmark current practices for DMS implementation to serve as a guide for future system implementations. The survey sought information on current plans to implement DMS, DMS functions of interest, implementation challenges, functional benefits achieved, and other relevant information. These survey results were combined (where possible) with results of similar surveys conducted in the previous four years to observe trends over time.

The Black Hull Fleet: Multi-Function Assets for Multi-Mission Duty

DTIC Science & Technology

2011-01-01

also conduct annual training and mock ex- ercises using pre-staged vessel of opportunity skimming system gear, and all crews receive hazardous waste...Valdez oil spill in 1989, the Oil Pollution Act of 1990 mandated that they be outfittedwith an onboard spilled oil recovery system (SORS) comprised of... outriggers , booms, hydraulic skim- ming equipment, and product storage vessels. The“Black Hull” Fleet Multi-function assets for multi-mission duty. by

Synthesis of functionalized indolizidines through Pauson-Khand cycloaddition of 2-allylpyrrolidines.

PubMed

McCormack, Michael P; Waters, Stephen P

2013-02-01

A concise entry to functionalized indolizidine scaffolds through a domino 2-aza-Cope-[3 + 2] dipolar cycloaddition and Pauson-Khand [2 + 2 + 1] cyclization has been accomplished. The process was conducted under mild conditions to afford diverse indolizidine systems as single diastereomers in good overall yields.

Synthesis of Functionalized Indolizidines through Pauson–Khand Cycloaddition of 2-Allylpyrrolidines

PubMed Central

McCormack, Michael P.

2013-01-01

A concise entry to functionalized indolizidine scaffolds through a domino 2-aza-Cope-[3+2] dipolar cycloaddition and Pauson–Khand [2+2+1] cyclization has been accomplished. The process was conducted under mild conditions to afford diverse indolizidine systems as single diastereomers in good overall yields. PMID:23311620

Sympathetic nervous system activity measured by skin conductance quantifies the challenge of walking adaptability tasks after stroke.

PubMed

Clark, David J; Chatterjee, Sudeshna A; McGuirk, Theresa E; Porges, Eric C; Fox, Emily J; Balasubramanian, Chitralakshmi K

2018-02-01

Walking adaptability tasks are challenging for people with motor impairments. The construct of perceived challenge is typically measured by self-report assessments, which are susceptible to subjective measurement error. The development of an objective physiologically-based measure of challenge may help to improve the ability to assess this important aspect of mobility function. The objective of this study to investigate the use of sympathetic nervous system (SNS) activity measured by skin conductance to gauge the physiological stress response to challenging walking adaptability tasks in people post-stroke. Thirty adults with chronic post-stroke hemiparesis performed a battery of seventeen walking adaptability tasks. SNS activity was measured by skin conductance from the palmar surface of each hand. The primary outcome variable was the percent change in skin conductance level (ΔSCL) between the baseline resting and walking phases of each task. Task difficulty was measured by performance speed and by physical therapist scoring of performance. Walking function and balance confidence were measured by preferred walking speed and the Activities-specific Balance Confidence Scale, respectively. There was a statistically significant negative association between ΔSCL and task performance speed and between ΔSCL and clinical score, indicating that tasks with greater SNS activity had slower performance speed and poorer clinical scores. ΔSCL was significantly greater for low functioning participants versus high functioning participants, particularly during the most challenging walking adaptability tasks. This study supports the use of SNS activity measured by skin conductance as a valuable approach for objectively quantifying the perceived challenge of walking adaptability tasks in people post-stroke. Published by Elsevier B.V.

Sympathetic nervous system activity measured by skin conductance quantifies the challenge of walking adaptability tasks after stroke

PubMed Central

Clark, David J.; Chatterjee, Sudeshna A.; McGuirk, Theresa E.; Porges, Eric C.; Fox, Emily J.; Balasubramanian, Chitralakshmi K.

2018-01-01

Background Walking adaptability tasks are challenging for people with motor impairments. The construct of perceived challenge is typically measured by self-report assessments, which are susceptible to subjective measurement error. The development of an objective physiologically-based measure of challenge may help to improve the ability to assess this important aspect of mobility function. The objective of this study to investigate the use of sympathetic nervous system (SNS) activity measured by skin conductance to gauge the physiological stress response to challenging walking adaptability tasks in people post-stroke. Methods Thirty adults with chronic post-stroke hemiparesis performed a battery of seventeen walking adaptability tasks. SNS activity was measured by skin conductance from the palmar surface of each hand. The primary outcome variable was the percent change in skin conductance level (ΔSCL) between the baseline resting and walking phases of each task. Task difficulty was measured by performance speed and by physical therapist grading of performance. Walking function and balance confidence were measured by preferred walking speed and the Activities Specific Balance Confidence Scale, respectively. Results There was a statistically significant negative association between ΔSCL and task performance speed and between ΔSCL and clinical score, indicating that tasks with greater SNS activity had slower performance speed and poorer clinical scores. ΔSCL was significantly greater for low functioning participants versus high functioning participants, particularly during the most challenging walking adaptability tasks. Conclusion This study supports the use of SNS activity measured by skin conductance as a valuable approach for objectively quantifying the perceived challenge of walking adaptability tasks in people post-stroke. PMID:29216598

Coherent radar estimates of high latitude field-aligned currents: the importance of conductance gradients

NASA Astrophysics Data System (ADS)

Kosch, M.; Nielsen, E.

Two bi-static VHF radar systems STARE and SABRE have been employed to estimate ionospheric electric field distributions in the geomagnetic latitude range 61 1 - 69 3 degrees over Scandinavia corresponding to the global Region 2 current system 173 days of data from all four radars have been analysed during the period 1982 to 1986 The average magnetic field-aligned currents have been computed as a function of the Kp and Ae indices using an empirical model of ionospheric Pedersen and Hall conductance taking into account conductance gradients The divergence of horizontal Pedersen currents and Hall conductance gradients have approximately the same importance for generating the Region 2 field-aligned currents Pedersen conductance gradients have a significant modifying effect A case study of field-aligned currents has been performed using the STARE radar system to obtain the instantaneous ionospheric electric field distribution in the vicinity of an auroral arc The instantaneous Hall conductance was estimated from the Scandinavian Magnetometer Array This study clearly shows that even for quiet steady state geomagnetic conditions conductance gradients are important modifiers of magnetic field-aligned currents

Graphene Nanopore Support System for Simultaneous High-Resolution AFM Imaging and Conductance Measurements

PubMed Central

2015-01-01

Accurately defining the nanoporous structure and sensing the ionic flow across nanoscale pores in thin films and membranes has a wide range of applications, including characterization of biological ion channels and receptors, DNA sequencing, molecule separation by nanoparticle films, sensing by block co-polymers films, and catalysis through metal–organic frameworks. Ionic conductance through nanopores is often regulated by their 3D structures, a relationship that can be accurately determined only by their simultaneous measurements. However, defining their structure–function relationships directly by any existing techniques is still not possible. Atomic force microscopy (AFM) can image the structures of these pores at high resolution in an aqueous environment, and electrophysiological techniques can measure ion flow through individual nanoscale pores. Combining these techniques is limited by the lack of nanoscale interfaces. We have designed a graphene-based single-nanopore support (∼5 nm thick with ∼20 nm pore diameter) and have integrated AFM imaging and ionic conductance recording using our newly designed double-chamber recording system to study an overlaid thin film. The functionality of this integrated system is demonstrated by electrical recording (<10 pS conductance) of suspended lipid bilayers spanning a nanopore and simultaneous AFM imaging of the bilayer. PMID:24581087

Steady state conductance in a double quantum dot array: the nonequilibrium equation-of-motion Green function approach.

PubMed

Levy, Tal J; Rabani, Eran

2013-04-28

We study steady state transport through a double quantum dot array using the equation-of-motion approach to the nonequilibrium Green functions formalism. This popular technique relies on uncontrolled approximations to obtain a closure for a hierarchy of equations; however, its accuracy is questioned. We focus on 4 different closures, 2 of which were previously proposed in the context of the single quantum dot system (Anderson impurity model) and were extended to the double quantum dot array, and develop 2 new closures. Results for the differential conductance are compared to those attained by a master equation approach known to be accurate for weak system-leads couplings and high temperatures. While all 4 closures provide an accurate description of the Coulomb blockade and other transport properties in the single quantum dot case, they differ in the case of the double quantum dot array, where only one of the developed closures provides satisfactory results. This is rationalized by comparing the poles of the Green functions to the exact many-particle energy differences for the isolate system. Our analysis provides means to extend the equation-of-motion technique to more elaborate models of large bridge systems with strong electronic interactions.

Alterations of Brain Functional Architecture Associated with Psychopathic Traits in Male Adolescents with Conduct Disorder.

PubMed

Pu, Weidan; Luo, Qiang; Jiang, Yali; Gao, Yidian; Ming, Qingsen; Yao, Shuqiao

2017-09-12

Psychopathic traits of conduct disorder (CD) have a core callous-unemotional (CU) component and an impulsive-antisocial component. Previous task-driven fMRI studies have suggested that psychopathic traits are associated with dysfunction of several brain areas involved in different cognitive functions (e.g., empathy, reward, and response inhibition etc.), but the relationship between psychopathic traits and intrinsic brain functional architecture has not yet been explored in CD. Using a holistic brain-wide functional connectivity analysis, this study delineated the alterations in brain functional networks in patients with conduct disorder. Compared with matched healthy controls, we found decreased anti-synchronization between the fronto-parietal network (FPN) and default mode network (DMN), and increased intra-network synchronization within the frontothalamic-basal ganglia, right frontoparietal, and temporal/limbic/visual networks in CD patients. Correlation analysis showed that the weakened FPN-DMN interaction was associated with CU traits, while the heightened intra-network functional connectivity was related to impulsivity traits in CD patients. Our findings suggest that decoupling of cognitive control (FPN) with social understanding of others (DMN) is associated with the CU traits, and hyper-functions of the reward and motor inhibition systems elevate impulsiveness in CD.

Development of human factors guidelines for advanced traveler information systems and commercial vehicle operations : task analysis of ATIS/CVO functions

DOT National Transportation Integrated Search

1996-11-01

This working paper documents Task E of the present project, Task Analyses for Advanced Traveler Information Systems (ATIS) and Commercial Vehicle Operations (CVO) systems. The goal of Task E is to conduct detailed analyses of the influence of using A...

Developing Environmental Scanning/Forecasting Systems To Augment Community College Planning.

ERIC Educational Resources Information Center

Morrison, James L.; Held, William G.

A description is provided of a conference session that was conducted to explore the structure and function of an environmental scanning/forecasting system that could be used in a community college to facilitate planning. Introductory comments argue that a college that establishes an environmental scanning and forecasting system is able to identify…

Calibration of a texture-based model of a ground-water flow system, western San Joaquin Valley, California

USGS Publications Warehouse

Phillips, Steven P.; Belitz, Kenneth

1991-01-01

The occurrence of selenium in agricultural drain water from the western San Joaquin Valley, California, has focused concern on the semiconfined ground-water flow system, which is underlain by the Corcoran Clay Member of the Tulare Formation. A two-step procedure is used to calibrate a preliminary model of the system for the purpose of determining the steady-state hydraulic properties. Horizontal and vertical hydraulic conductivities are modeled as functions of the percentage of coarse sediment, hydraulic conductivities of coarse-textured (Kcoarse) and fine-textured (Kfine) end members, and averaging methods used to calculate equivalent hydraulic conductivities. The vertical conductivity of the Corcoran (Kcorc) is an additional parameter to be evaluated. In the first step of the calibration procedure, the model is run by systematically varying the following variables: (1) Kcoarse/Kfine, (2) Kcoarse/Kcorc, and (3) choice of averaging methods in the horizontal and vertical directions. Root mean square error and bias values calculated from the model results are functions of these variables. These measures of error provide a means for evaluating model sensitivity and for selecting values of Kcoarse, Kfine, and Kcorc for use in the second step of the calibration procedure. In the second step, recharge rates are evaluated as functions of Kcoarse, Kcorc, and a combination of averaging methods. The associated Kfine values are selected so that the root mean square error is minimized on the basis of the results from the first step. The results of the two-step procedure indicate that the spatial distribution of hydraulic conductivity that best produces the measured hydraulic head distribution is created through the use of arithmetic averaging in the horizontal direction and either geometric or harmonic averaging in the vertical direction. The equivalent hydraulic conductivities resulting from either combination of averaging methods compare favorably to field- and laboratory-based values.

NASA Graduate Student Researchers Program (GSRP)

NASA Technical Reports Server (NTRS)

Freeman, Frederick G.

1998-01-01

The primary area of research that Dr. Prinzel conducted was concerned with the effects of automation on the ability to perform various tasks which simulated those performed in an airplane cockpit. While automation is generally considered to be a positive addition to the cockpit, it also has some negative effects. The primary negative effect is related to the decrease in the number of tasks the pilot needs to perform. Having less to do can actually result in a decreased ability to be aware of and react to ongoing events, some of which may be critical to flight operations. The research was concerned with the ability of adaptive automation using psychophysiological measures, specifically brain waves (i.e. EEG), to control the degree to which tasks are automated as a function of the subject's level of alertness. Dr. Prinzel conducted and participated in the running of a number of experiments that examined adaptive automation in conjunction with the MultiAttribute Task Battery. Since there has been very little research conducted in this area, experiments needed to be conducted which established basic parameters for future research. The experiments that Dr. Prinzel was involved with examined the optimum number and location of electrode sites for recording EEG, the types of tasks which could readily be automated, the number of tasks which could be controlled by the adaptive automation system, and various EEG recording parameters which affect system functioning. A secondary area in which Dr. Prinzel conducted research concerned performance on vigiliance tasks. This research, while not initially directly related to adaptive automation, does have implication for such systems. Vigilance requires long term monitoring which often leads to the kind of negative effects seen when automation is introduced into a work environment. A third area of research in which Dr. Prinzel conducted research was concerned with gender differences in cognitive functioning and how that related to strategies for performing various tasks.

Optical response tuning in nanorod-on-semicontinous film systems: A computational study

NASA Astrophysics Data System (ADS)

Mokkath, Junais Habeeb

2018-01-01

Strongly confined and intense optical fields within the plasmonic metal nanocavities show outstanding potential for a wide range of functionalities in nanophotonics. Using time dependent density functional theory calculations, we investigate the optical response evolution as a function of the gap separation distances in nanorod-on-film systems comprised of a nanorod (NR) made of Al or Na on top of an Al film. Huge optical field modulations emerged in the chemically distinct Na NR - Al film system in comparison to the Al NR - Al film system, indicating the vital role of metals involved. We further study the optical response modifications by placing a conducting molecule in the gap region, finding strong spectral modulations via through-molecule electron tunneling.

An Analysis of Fuel Cell Options for an All-electric Unmanned Aerial Vehicle

NASA Technical Reports Server (NTRS)

Kohout, Lisa L.; Schmitz, Paul C.

2007-01-01

A study was conducted to assess the performance characteristics of both PEM and SOFC-based fuel cell systems for an all-electric high altitude, long endurance Unmanned Aerial Vehicle (UAV). Primary and hybrid systems were considered. Fuel options include methane, hydrogen, and jet fuel. Excel-based models were used to calculate component mass as a function of power level and mission duration. Total system mass and stored volume as a function of mission duration for an aircraft operating at 65 kft altitude were determined and compared.

Theoretical analysis of a dual-probe scanning tunneling microscope setup on graphene.

PubMed

Settnes, Mikkel; Power, Stephen R; Petersen, Dirch H; Jauho, Antti-Pekka

2014-03-07

Experimental advances allow for the inclusion of multiple probes to measure the transport properties of a sample surface. We develop a theory of dual-probe scanning tunneling microscopy using a Green's function formalism, and apply it to graphene. Sampling the local conduction properties at finite length scales yields real space conductance maps which show anisotropy for pristine graphene systems and quantum interference effects in the presence of isolated impurities. Spectral signatures in the Fourier transforms of real space conductance maps include characteristics that can be related to different scattering processes. We compute the conductance maps of graphene systems with different edge geometries or height fluctuations to determine the effects of nonideal graphene samples on dual-probe measurements.

Understanding Nanoscale Thermal Conduction an Mechanical Strength Correlation in High Temperature Ceramics with Improved Thermal Shock Resistance for Aerospace Applications

DTIC Science & Technology

2012-08-08

simulation data is available on this system. Molecular simulation , ab initio simulations , thermal conductivity, biomimetic materials, phase transformation...MOLECULAR SIMULATIONS …………….. 28 §2.2.1 THERMAL CONDUCTION ANALYSES IN SUPERLATTICES AS A FUNCTION OF STRAIN……………………………………………………………. 29 §2.2.2...analyses also focus on Si-Ge interfaces and nanocomposites, as a lot of simulation data is available on this system. In terms of modeling the required

An NLRA Transducer for Dual Use Bone Conduction Audio and Haptic Communication. Summary Report

DTIC Science & Technology

2016-12-30

VIBRANT COMPOSITES INC. 1 A16-019 Phase 1 Summary Report Vibrant Composites Inc. December 30, 2016 I. ABSTRACT A combined transducer capable of bone ...transducer core capable of both precise haptic communication and high fidelity bone conduction audio. The transducer design leverages Micro-Multilayer...head-mounted system. In this Phase I SBIR, Vibrant Composites has delivered functional dual-mode bone conduction and vibrotactile transducer prototypes

Cognitive engineering models in space systems

NASA Technical Reports Server (NTRS)

Mitchell, Christine M.

1993-01-01

NASA space systems, including mission operations on the ground and in space, are complex, dynamic, predominantly automated systems in which the human operator is a supervisory controller. Models of cognitive functions in complex systems are needed to describe human performance and form the theoretical basis of operator workstation design, including displays, controls, and decision aids. Currently, there several candidate modeling methodologies. They include the Rasmussen abstraction/aggregation hierarchy and decision ladder, the goal-means network, the problem behavior graph, and the operator function model. The research conducted under the sponsorship of this grant focuses on the extension of the theoretical structure of the operator function model and its application to NASA Johnson mission operations and space station applications. The initial portion of this research consists of two parts. The first is a series of technical exchanges between NASA Johnson and Georgia Tech researchers. The purpose is to identify candidate applications for the current operator function model; prospects include mission operations and the Data Management System Testbed. The second portion will address extensions of the operator function model to tailor it to the specific needs of Johnson applications. At this point, we have accomplished two things. During a series of conversations with JSC researchers, we have defined the technical goal of the research supported by this grant to be the structural definition of the operator function model and its computer implementation, OFMspert. Both the OFM and OFMspert have matured to the point that they require infrastructure to facilitate use by researchers not involved in the evolution of the tools. The second accomplishment this year was the identification of the Payload Deployment and Retrieval System (PDRS) as a candidate system for the case study. In conjunction with government and contractor personnel in the Human-Computer Interaction Lab, the PDRS was identified as the most accessible system for the demonstration. Pursuant to this a PDRS simulation was obtained from the HCIL and an initial knowledge engineering effort was conducted to understand the operator's tasks in the PDRS application. The preliminary results of the knowledge engineering effort and an initial formulation of an operator function model (OFM) are contained in the appendices.

The medical story. [of Skylab

NASA Technical Reports Server (NTRS)

Johnston, R. S.; Dietlein, L. F.; Michel, E. L.

1975-01-01

The paper discusses the medical program of the Skylab missions. The major medical systems discussed include the food system, the waste-management system, the personal-hygiene system, and the inflight medical support system. The life-sciences experiments conducted on Skylab are reviewed. These dealt with the cardiovascular system, mineral balance and bioassay of fluids, sleep, blood, metabolic activity, vestibular function, and time and motion studies. The medical operations were accomplished with only minor problems.

AC conductivity and Dielectric Study of Chalcogenide Glasses of Se-Te-Ge System

NASA Astrophysics Data System (ADS)

Salman, Fathy

2004-01-01

The ac conductivity and dielectric properties of glassy system SexTe79 - xGe21, with x = 11, 14, 17 at.%, has been studied at temperatures 300 to 450 K and over a wide range of frequencies (50 Hz to 500 kHz). Experimental results indicate that the ac conductivity and the dielectric constants depend on temperature, frequency and Se content. The conductivity as a function of frequency exhibited two components: dc conductivity s dc, and ac conductivity s ac, where s ac ˜ w s. The mechanism of ac conductivity can be reasonably interpreted in terms of the correlated barrier hopping model (CBH). The activation energies are estimated and discussed. The dependence of ac conductivity and dielectric constants on the Se content x can be interpreted as the effect of Se fraction on the positional disorder. The impedance plot at each temperature appeared as a semicircle passes through the origin. Each semicircle is represented by an equivalent circuit of parallel resistance Rb and capacitance Cb.

Combined use of flowmeter and time-drawdown data to estimate hydraulic conductivities in layered aquifer systems

USGS Publications Warehouse

Hanson, R.T.; Nishikawa, T.

1996-01-01

The vertical distribution of hydraulic conductivity in layered aquifer systems commonly is needed for model simulations of ground-water flow and transport. In previous studies, time-drawdown data or flowmeter data were used individually, but not in combination, to estimate hydraulic conductivity. In this study, flowmeter data and time-drawdown data collected from a long-screened production well and nearby monitoring wells are combined to estimate the vertical distribution of hydraulic conductivity in a complex multilayer coastal aquifer system. Flowmeter measurements recorded as a function of depth delineate nonuniform inflow to the wellbore, and this information is used to better discretize the vertical distribution of hydraulic conductivity using analytical and numerical methods. The time-drawdown data complement the flowmeter data by giving insight into the hydraulic response of aquitards when flow rates within the wellbore are below the detection limit of the flowmeter. The combination of these field data allows for the testing of alternative conceptual models of radial flow to the wellbore.

Multiple sensor multifrequency eddy current monitor for solidification and growth

NASA Technical Reports Server (NTRS)

Wallace, John

1990-01-01

A compact cylindrical multisensor eddy current measuring system with integral furnace was develop to monitor II-VI crystal growth to provide interfacial information, solutal segregation, and conductivities of the growth materials. The use of an array of sensors surrounding the furnace element allows one to monitor the volume of interest. Coupling these data with inverse multifrequency analysis allows radial conductivity profiles to be generated at each sensor position. These outputs were incorporated to control the processes within the melt volume. The standard eddy current system functions with materials whose electric conductivities are as low as 2E2 Mhos/m. A need was seen to extend the measurement range to poorly conducting media so the unit was modified to allow measurement of materials conductivities 4 order of magnitude lower and bulk dielectric properties. Typically these included submicron thick films and semiinsulating GaAs. This system was used to monitor complex heat transfer in grey bodies as well as semiconductor and metallic solidification.

Structure and functionality of bromine doped graphite.

PubMed

Hamdan, Rashid; Kemper, A F; Cao, Chao; Cheng, H P

2013-04-28

First-principles calculations are used to study the enhanced in-plane conductivity observed experimentally in Br-doped graphite, and to study the effect of external stress on the structure and functionality of such systems. The model used in the numerical calculations is that of stage two doped graphite. The band structure near the Fermi surface of the doped systems with different bromine concentrations is compared to that of pure graphite, and the charge transfer between carbon and bromine atoms is analyzed to understand the conductivity change along different high symmetry directions. Our calculations show that, for large interlayer separation between doped graphite layers, bromine is stable in the molecular form (Br2). However, with increased compression (decreased layer-layer separation) Br2 molecules tend to dissociate. While in both forms, bromine is an electron acceptor. The charge exchange between the graphite layers and Br atoms is higher than that with Br2 molecules. Electron transfer to the Br atoms increases the number of hole carriers in the graphite sheets, resulting in an increase of conductivity.

Tuning the conductance of H2O@C60 by position of the encapsulated H2O

PubMed Central

Zhu, Chengbo; Wang, Xiaolin

2015-01-01

The change of conductance of single-molecule junction in response to various external stimuli is the fundamental mechanism for the single-molecule electronic devices with multiple functionalities. We propose the concept that the conductance of molecular systems can be tuned from inside. The conductance is varied in C60 with encapsulated H2O, H2O@C60. The transport properties of the H2O@C60-based nanostructure sandwiched between electrodes are studied using first-principles calculations combined with the non-equilibrium Green’s function formalism. Our results show that the conductance of the H2O@C60 is sensitive to the position of the H2O and its dipole direction inside the cage with changes in conductance up to 20%. Our study paves a way for the H2O@C60 molecule to be a new platform for novel molecule-based electronics and sensors. PMID:26643873

Magnetoacoustic tomography with magnetic induction for high-resolution bioimepedance imaging through vector source reconstruction under the static field of MRI magnet.

PubMed

Mariappan, Leo; Hu, Gang; He, Bin

2014-02-01

Magnetoacoustic tomography with magnetic induction (MAT-MI) is an imaging modality to reconstruct the electrical conductivity of biological tissue based on the acoustic measurements of Lorentz force induced tissue vibration. This study presents the feasibility of the authors' new MAT-MI system and vector source imaging algorithm to perform a complete reconstruction of the conductivity distribution of real biological tissues with ultrasound spatial resolution. In the present study, using ultrasound beamformation, imaging point spread functions are designed to reconstruct the induced vector source in the object which is used to estimate the object conductivity distribution. Both numerical studies and phantom experiments are performed to demonstrate the merits of the proposed method. Also, through the numerical simulations, the full width half maximum of the imaging point spread function is calculated to estimate of the spatial resolution. The tissue phantom experiments are performed with a MAT-MI imaging system in the static field of a 9.4 T magnetic resonance imaging magnet. The image reconstruction through vector beamformation in the numerical and experimental studies gives a reliable estimate of the conductivity distribution in the object with a ∼ 1.5 mm spatial resolution corresponding to the imaging system frequency of 500 kHz ultrasound. In addition, the experiment results suggest that MAT-MI under high static magnetic field environment is able to reconstruct images of tissue-mimicking gel phantoms and real tissue samples with reliable conductivity contrast. The results demonstrate that MAT-MI is able to image the electrical conductivity properties of biological tissues with better than 2 mm spatial resolution at 500 kHz, and the imaging with MAT-MI under a high static magnetic field environment is able to provide improved imaging contrast for biological tissue conductivity reconstruction.

The symmetry of single-molecule conduction.

PubMed

Solomon, Gemma C; Gagliardi, Alessio; Pecchia, Alessandro; Frauenheim, Thomas; Di Carlo, Aldo; Reimers, Jeffrey R; Hush, Noel S

2006-11-14

We introduce the conductance point group which defines the symmetry of single-molecule conduction within the nonequilibrium Green's function formalism. It is shown, either rigorously or to within a very good approximation, to correspond to a molecular-conductance point group defined purely in terms of the properties of the conducting molecule. This enables single-molecule conductivity to be described in terms of key qualitative chemical descriptors that are independent of the nature of the molecule-conductor interfaces. We apply this to demonstrate how symmetry controls the conduction through 1,4-benzenedithiol chemisorbed to gold electrodes as an example system, listing also the molecular-conductance point groups for a range of molecules commonly used in molecular electronics research.

High conductance values in π-folded molecular junctions

NASA Astrophysics Data System (ADS)

Carini, Marco; Ruiz, Marta P.; Usabiaga, Imanol; Fernández, José A.; Cocinero, Emilio J.; Melle-Franco, Manuel; Diez-Perez, Ismael; Mateo-Alonso, Aurelio

2017-05-01

Folding processes play a crucial role in the development of function in biomacromolecules. Recreating this feature on synthetic systems would not only allow understanding and reproducing biological functions but also developing new functions. This has inspired the development of conformationally ordered synthetic oligomers known as foldamers. Herein, a new family of foldamers, consisting of an increasing number of anthracene units that adopt a folded sigmoidal conformation by a combination of intramolecular hydrogen bonds and aromatic interactions, is reported. Such folding process opens up an efficient through-space charge transport channel across the interacting anthracene moieties. In fact, single-molecule conductance measurements carried out on this series of foldamers, using the scanning tunnelling microscopy-based break-junction technique, reveal exceptionally high conductance values in the order of 10-1 G0 and a low length decay constant of 0.02 Å-1 that exceed the values observed in molecular junctions that make use of through-space charge transport pathways.

[Functional state of vision system under chronic mercury intoxication].

PubMed

Iablonskaia, D A; Mishchenko, T S; Lakhman, O L; Rukavishnikov, V S; Malyshev, V V

2010-01-01

Examination of chronic mercury intoxication patients in distant (post-contact) period revealed marked vision disorders and inhibited neuro-conductivity--inhibited neuronal structures of retina and optic nerve.

12 CFR 1101.2 - Authority and functions.

Code of Federal Regulations, 2011 CFR

2011-01-01

.... The Council is empowered to prescribe uniform principles, standards, and reporting forms and systems; make recommendations in the interest of uniformity; and conduct examiner schools open to personnel of...

12 CFR 1101.2 - Authority and functions.

Code of Federal Regulations, 2014 CFR

2014-01-01

.... The Council is empowered to prescribe uniform principles, standards, and reporting forms and systems; make recommendations in the interest of uniformity; and conduct examiner schools open to personnel of...

12 CFR 1101.2 - Authority and functions.

Code of Federal Regulations, 2012 CFR

2012-01-01

.... The Council is empowered to prescribe uniform principles, standards, and reporting forms and systems; make recommendations in the interest of uniformity; and conduct examiner schools open to personnel of...

12 CFR 1101.2 - Authority and functions.

Code of Federal Regulations, 2013 CFR

2013-01-01

.... The Council is empowered to prescribe uniform principles, standards, and reporting forms and systems; make recommendations in the interest of uniformity; and conduct examiner schools open to personnel of...

12 CFR 1101.2 - Authority and functions.

Code of Federal Regulations, 2010 CFR

2010-01-01

.... The Council is empowered to prescribe uniform principles, standards, and reporting forms and systems; make recommendations in the interest of uniformity; and conduct examiner schools open to personnel of...

Automated vehicle location, data recording, friction measurement and applicator control for winter road maintenance.

DOT National Transportation Integrated Search

2010-02-01

The first part of this project conducted a detailed evaluation of the ability of a new friction measurement system to : provide an accurate measure of road conditions. A system that records friction coefficient as a function of road : location was de...

17 CFR 200.19a - Director of the Division of Trading and Markets.

Code of Federal Regulations, 2011 CFR

2011-04-01

... COMMISSION ORGANIZATION; CONDUCT AND ETHICS; AND INFORMATION AND REQUESTS Organization and Program Management... responsibilities include oversight of the national market system, the national clearance and settlement system, and... and dealers, transfer agents, and securities information processors. The functions involved in the...

The role of man in flight experiment payload missions. Volume 2: Appendices

NASA Technical Reports Server (NTRS)

Malone, T. B.

1973-01-01

In the study to determine the role of man in Sortie Lab operations, a functional model of a generalized experiment system was developed. The results are presented of a requirements analysis which was conducted to identify performance requirements, information requirements, and interface requirements associated with each function in the model.

East Tennessee State University's "Make a Difference" Project: Using a Team-Based Consultative Model To Conduct Functional Behavioral Assessments.

ERIC Educational Resources Information Center

Vaughn, Kelley; Hales, Cindy; Bush, Marta; Fox, James

1998-01-01

Describes implementation of functional behavioral assessment (FBA) through collaboration between a university (East Tennessee State University) and the local school system. Discusses related issues such as factors in team training, team size, FBA adaptations, and replicability of the FBA team model. (Author/DB)

A Functional Study of "zhi [Chinese character omitted]" in the Chinese Nominal Group

ERIC Educational Resources Information Center

Zhang, Weiwei; Li, Manliang

2017-01-01

Over the past decades, subjects concerned with the Chinese character "zhi [Chinese character omitted]", i.e. grammatical structure, in ancient Chinese language, have been widely explored. This paper conducts a research from a new dimension: the Cardiff Grammar, an integral part of Systemic Functional Linguistics (SFL) which is famous for…

Ab initio electronic transport and thermoelectric properties of solids from full and range-separated hybrid functionals

NASA Astrophysics Data System (ADS)

Sansone, Giuseppe; Ferretti, Andrea; Maschio, Lorenzo

2017-09-01

Within the semiclassical Boltzmann transport theory in the constant relaxation-time approximation, we perform an ab initio study of the transport properties of selected systems, including crystalline solids and nanostructures. A local (Gaussian) basis set is adopted and exploited to analytically evaluate band velocities as well as to access full and range-separated hybrid functionals (such as B3LYP, PBE0, or HSE06) at a moderate computational cost. As a consequence of the analytical derivative, our approach is computationally efficient and does not suffer from problems related to band crossings. We investigate and compare the performance of a variety of hybrid functionals in evaluating Boltzmann conductivity. Demonstrative examples include silicon and aluminum bulk crystals as well as two thermoelectric materials (CoSb3, Bi2Te3). We observe that hybrid functionals other than providing more realistic bandgaps—as expected—lead to larger bandwidths and hence allow for a better estimate of transport properties, also in metallic systems. As a nanostructure prototype, we also investigate conductivity in boron-nitride (BN) substituted graphene, in which nanoribbons (nanoroads) alternate with BN ones.

Dynamic Stiffness Transfer Function of an Electromechanical Actuator Using System Identification

NASA Astrophysics Data System (ADS)

Kim, Sang Hwa; Tahk, Min-Jea

2018-04-01

In the aeroelastic analysis of flight vehicles with electromechanical actuators (EMAs), an accurate prediction of flutter requires dynamic stiffness characteristics of the EMA. The dynamic stiffness transfer function of the EMA with brushless direct current (BLDC) motor can be obtained by conducting complicated mathematical calculations of control algorithms and mechanical/electrical nonlinearities using linearization techniques. Thus, system identification approaches using experimental data, as an alternative, have considerable advantages. However, the test setup for system identification is expensive and complex, and experimental procedures for data collection are time-consuming tasks. To obtain the dynamic stiffness transfer function, this paper proposes a linear system identification method that uses information obtained from a reliable dynamic stiffness model with a control algorithm and nonlinearities. The results of this study show that the system identification procedure is compact, and the transfer function is able to describe the dynamic stiffness characteristics of the EMA. In addition, to verify the validity of the system identification method, the simulation results of the dynamic stiffness transfer function and the dynamic stiffness model were compared with the experimental data for various external loads.

Wireless Network for Measurement of Whole-Body Vibration

PubMed Central

Koenig, Diogo; Chiaramonte, Marilda S.; Balbinot, Alexandre

2008-01-01

This article presents the development of a system integrated to a ZigBee network to measure whole-body vibration. The developed system allows distinguishing human vibrations of almost 400Hz in three axes with acceleration of almost 50g. The tests conducted in the study ensured the correct functioning of the system for the project's purpose. PMID:27879866

Microcomputer-Based Detachment Administrative Management System for the LAMPS (Light Airborne Multi-Purpose System) Community. A Requirements Analysis.

DTIC Science & Technology

1985-09-01

management and recurring reports generation . Included are the results of user interviews which were conducted to determine oossible system functions...9 A. GENERAL ...................... .......... 3 B. RESEARCH OBJECTIVES ............................ I0 C. SCOPE .. D... GENERAL DESCRIPTION (LAMPS) ...................... 9. LPMrOS CRGANIZAT r.N ............................... C. REPCRT>1NG RECLUIRE,’ENTS

Measures of Autonomic Nervous System

DTIC Science & Technology

2011-04-01

activation encompass non-invasive tools, which measure cardiac, skin conductance, respiratory , and vascular activity. Choice of tools is dependent upon...digestion, excretion, and cardiac and respiratory activity. The ANS consists of the sympathetic and parasympathetic divisions and acts through a... respiratory cycles. Generally, these two systems should be seen as permanently modulating vital functions to achieve homeostasis. Since both systems are

Increasing component functionality via multi-process additive manufacturing

NASA Astrophysics Data System (ADS)

Coronel, Jose L.; Fehr, Katherine H.; Kelly, Dominic D.; Espalin, David; Wicker, Ryan B.

2017-05-01

Additively manufactured components, although extensively customizable, are often limited in functionality. Multi-process additive manufacturing (AM) grants the ability to increase the functionality of components via subtractive manufacturing, wire embedding, foil embedding and pick and place. These processes are scalable to include several platforms ranging from desktop to large area printers. The Multi3D System is highlighted, possessing the capability to perform the above mentioned processes, all while transferring a fabricated component with a robotic arm. Work was conducted to fabricate a patent inspired, printed missile seeker. The seeker demonstrated the advantage of multi-process AM via introduction of the pick and place process. Wire embedding was also explored, with the successful interconnect of two layers of embedded wires in different planes. A final demonstration of a printed contour bracket, served to show the reduction of surface roughness on a printed part is 87.5% when subtractive manufacturing is implemented in tandem with AM. Functionality of the components on all the cases was improved. Results included optical components embedded within the printed housing, wires embedded with interconnection, and reduced surface roughness. These results highlight the improved functionality of components through multi-process AM, specifically through work conducted with the Multi3D System.

The Lattice and Thermal Radiation Conductivity of Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Spuckler, Charles M.

2008-01-01

The lattice and radiation conductivity of thermal barrier coatings was evaluated using a laser heat flux approach. A diffusion model has been established to correlate the apparent thermal conductivity of the coating to the lattice and radiation conductivity. The radiation conductivity component can be expressed as a function of temperature and the scattering and absorption properties of the coating material. High temperature scattering and absorption of the coating systems can also be derived based on the testing results using the modeling approach. The model prediction is found to have good agreement with experimental observations.

Design review report for the SY-101 RAPID mitigation system

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

SCHLOSSER, R.L.

1999-05-24

This report documents design reviews conducted of the SY-101 Respond And Pump In Days (RAPID) Mitigation System. As part of the SY-101 Surface-Level-Rise Remediation Project, the SY-101 WID Mitigation System will reduce the potential unacceptable consequences of crust growth in Tank 241-SY-101 (SY-101). Projections of the crust growth rate indicate that the waste level in the tank may reach the juncture of the primary and secondary confinement structures of the tank late in 1999. Because of this time constraint, many design activities are being conducted in parallel and design reviews were conducted for system adequacy as well as design implementationmore » throughout the process. Design implementation, as used in this design review report, is the final component selection (e.g., which circuit breaker, valve, or thermocouple) that meets the approved design requirements, system design, and design and procurement specifications. Design implementation includes the necessary analysis, testing, verification, and qualification to demonstrate compliance with the system design and design requirements. Design implementation is outside the scope of this design review. The design activities performed prior to detailed design implementation (i.e., system mission requirements, functional design requirements, technical criteria, system conceptual design, and where design and build contracts were placed, the procurement specification) have been reviewed and are within the scope of this design review report. Detailed design implementation will be controlled, reviewed, and where appropriate, approved in accordance with Tank Waste Remediation System (TWRS) engineering procedures. Review of detailed design implementation will continue until all components necessary to perform the transfer function are installed and tested.« less

Computing rates of Markov models of voltage-gated ion channels by inverting partial differential equations governing the probability density functions of the conducting and non-conducting states.

PubMed

Tveito, Aslak; Lines, Glenn T; Edwards, Andrew G; McCulloch, Andrew

2016-07-01

Markov models are ubiquitously used to represent the function of single ion channels. However, solving the inverse problem to construct a Markov model of single channel dynamics from bilayer or patch-clamp recordings remains challenging, particularly for channels involving complex gating processes. Methods for solving the inverse problem are generally based on data from voltage clamp measurements. Here, we describe an alternative approach to this problem based on measurements of voltage traces. The voltage traces define probability density functions of the functional states of an ion channel. These probability density functions can also be computed by solving a deterministic system of partial differential equations. The inversion is based on tuning the rates of the Markov models used in the deterministic system of partial differential equations such that the solution mimics the properties of the probability density function gathered from (pseudo) experimental data as well as possible. The optimization is done by defining a cost function to measure the difference between the deterministic solution and the solution based on experimental data. By evoking the properties of this function, it is possible to infer whether the rates of the Markov model are identifiable by our method. We present applications to Markov model well-known from the literature. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Operator Support System Design forthe Operation of RSG-GAS Research Reactor

NASA Astrophysics Data System (ADS)

Santoso, S.; Situmorang, J.; Bakhri, S.; Subekti, M.; Sunaryo, G. R.

2018-02-01

The components of RSG-GAS main control room are facing the problem of material ageing and technology obsolescence as well, and therefore the need for modernization and refurbishment are essential. The modernization in control room can be applied on the operator support system which bears the function in providing information for assisting the operator in conducting diagnosis and actions. The research purpose is to design an operator support system for RSG-GAS control room. The design was developed based on the operator requirement in conducting task operation scenarios and the reactor operation characteristics. These scenarios include power operation, low power operation and shutdown/scram reactor. The operator support system design is presented in a single computer display which contains structure and support system elements e.g. operation procedure, status of safety related components and operational requirements, operation limit condition of parameters, alarm information, and prognosis function. The prototype was developed using LabView software and consisted of components structure and features of the operator support system. Information of each component in the operator support system need to be completed before it can be applied and integrated in the RSG-GAS main control room.

Multi-Dimensional Sensors and Sensing Systems

NASA Technical Reports Server (NTRS)

Stetter, Joseph R. (Inventor); Shirke, Amol G. (Inventor)

2014-01-01

A universal microelectromechanical (MEMS) nano-sensor platform having a substrate and conductive layer deposited in a pattern on the surface to make several devices at the same time, a patterned insulation layer, wherein the insulation layer is configured to expose one or more portions of the conductive layer, and one or more functionalization layers deposited on the exposed portions of the conductive layer to make multiple sensing capability on a single MEMS fabricated device. The functionalization layers are adapted to provide one or more transducer sensor classes selected from the group consisting of: radiant, electrochemical, electronic, mechanical, magnetic, and thermal sensors for chemical and physical variables and producing more than one type of sensor for one or more significant parameters that need to be monitored.

Evaluation of telemedicine centres in Madhya Pradesh, Central India.

PubMed

Bali, Surya; Gupta, Arti; Khan, Asif; Pakhare, Abhijit

2016-04-01

In a developing country such as India, there is substantial inequality in health care distribution. Telemedicine facilities were established in Madhya Pradesh in 2007-2008. The purpose of this study was to evaluate the infrastructure, equipment, manpower, and functional status of Indian Space and Research Organisation (ISRO) telemedicine nodes in Madhya Pradesh. All district hospitals and medical colleges with nodes were visited by a team of three members. The study was conducted from December 2013-January 2014. The team recorded the structural facility situation and physical conditions on a predesigned pro forma. The team also conducted interviews with the nodal officers, data entry operator and other relevant people at these centres. Of the six specialist nodes, four were functional and two were non-functional. Of 10 patient nodes, two nodes were functional, four were semi-functional and four were non-functional. Most of the centres were not working due to a problem with their satellite modem. The overall condition of ISRO run telemedicine centres in Madhya Pradesh was found to be poor. Most of these centres failed to provide telemedicine consultations. We recommend replacing this system with another cost effective system available in the state wide area network (SWAN). We suggest the concept of the virtual out-patient department. © The Author(s) 2015.

Content Management Systems

ERIC Educational Resources Information Center

Wisniewski, Jeff; Stenstrom, Cheryl

2007-01-01

In this article, the authors provide a guide in acquiring content management system. They conducted a vendor survey that covers four areas: (1) general information about the product (including standards supported); (2) administration of the product; (3) functionality; and (4) contact information for readers who want to know more. A list of product…

Advanced single permanent magnet axipolar ironless stator ac motor for electric passenger vehicles

NASA Technical Reports Server (NTRS)

Beauchamp, E. D.; Hadfield, J. R.; Wuertz, K. L.

1983-01-01

A program was conducted to design and develop an advanced-concept motor specifically created for propulsion of electric vehicles with increased range, reduced energy consumption, and reduced life-cycle costs in comparison with conventional systems. The motor developed is a brushless, dc, rare-earth cobalt, permanent magnet, axial air gap inductor machine that uses an ironless stator. Air cooling is inherent provided by the centrifugal-fan action of the rotor poles. An extensive design phase was conducted, which included analysis of the system performance versus the SAE J227a(D) driving cycle. A proof-of-principle model was developed and tested, and a functional model was developed and tested. Full generator-level testing was conducted on the functional model, recording electromagnetic, thermal, aerodynamic, and acoustic noise data. The machine demonstrated 20.3 kW output at 1466 rad/s and 160 dc. The novel ironless stator demonstated the capability to continuously operate at peak current. The projected system performance based on the use of a transistor inverter is 23.6 kW output power at 1466 rad/s and 83.3 percent efficiency. Design areas of concern regarding electric vehicle applications include the inherently high windage loss and rotor inertia.

Cardiac Abnormalities in Primary Hyperoxaluria

PubMed Central

Mookadam, Farouk; Smith, Travis; Jiamsripong, Panupong; Moustafa, Sherif E; Monico, Carla G.; Lieske, John C.; Milliner, Dawn S.

2018-01-01

Background In patients with primary hyperoxaluria (PH), oxalate overproduction can result in recurrent urolithiasis and nephrocalcinosis, which in some cases results in a progressive decline in renal function, oxalate retention, and systemic oxalosis involving bone, retina, arterial media, peripheral nerves, skin, and heart. Oxalosis involving the myocardium or conduction system can potentially lead to heart failure and fatal arrhythmias. Methods and Results A retrospective review of our institution’s database was conducted for all patients with a confirmed diagnosis of PH between 1/1948 and 1/2006 (n=103). Electrocardiogram (ECG) and echocardiography were used to identify cardiac abnormalities. Ninety-three patients fulfilled the inclusion criteria, 58% were male. Mean follow-up was 11.9 (median 8.8) years. In 38 patients who received an ECG or echocardiography, 31 were found to have any cardiac abnormalities. Cardiac findings correlated with decline in renal function. Conclusions Our data suggests that physicians caring for patients with PH should pay close attention to cardiac status, especially if renal function is impaired. PMID:20921818

Flight experience with a fail-operational digital fly-by-wire control system

NASA Technical Reports Server (NTRS)

Brown, S. R.; Szalai, K. J.

1977-01-01

The NASA Dryden Flight Research Center is flight testing a triply redundant digital fly-by-wire (DFBW) control system installed in an F-8 aircraft. The full-time, full-authority system performs three-axis flight control computations, including stability and command augmentation, autopilot functions, failure detection and isolation, and self-test functions. Advanced control law experiments include an active flap mode for ride smoothing and maneuver drag reduction. This paper discusses research being conducted on computer synchronization, fault detection, fault isolation, and recovery from transient faults. The F-8 DFBW system has demonstrated immunity from nuisance fault declarations while quickly identifying truly faulty components.

Mechanical system diagnostics using vibration testing techniques

NASA Technical Reports Server (NTRS)

Mcleod, Catherine D.; Raju, P. K.; Crocker, M. J.

1990-01-01

The 'Cepstrum' technique of vibration-path identification allows the recovery of the transfer function of a system with little knowledge as to its excitation force, by means of a mathematical manipulation of the system output in conjunction with subtraction of part of the output and suitable signal processing. An experimental program has been conducted to evaluate the usefulness of this technique in the cases of simple, cantilever-beam and free-free plate structures as well as in that of a complex mechanical system. On the basis of the transfer functions thus recovered, it was possible to evaluate the shifts in the resonance frequencies of a structure due to the presence of defects.

Advanced flight deck/crew station simulator functional requirements

NASA Technical Reports Server (NTRS)

Wall, R. L.; Tate, J. L.; Moss, M. J.

1980-01-01

This report documents a study of flight deck/crew system research facility requirements for investigating issues involved with developing systems, and procedures for interfacing transport aircraft with air traffic control systems planned for 1985 to 2000. Crew system needs of NASA, the U.S. Air Force, and industry were investigated and reported. A matrix of these is included, as are recommended functional requirements and design criteria for simulation facilities in which to conduct this research. Methods of exploiting the commonality and similarity in facilities are identified, and plans for exploiting this in order to reduce implementation costs and allow efficient transfer of experiments from one facility to another are presented.

[Pathophysiology of heat illness].

PubMed

Aruga, Tohru; Miyake, Yasufumi

2012-06-01

Human core temperature is strictly controlled by mechanism of radiation, conduction, convection, and evaporation from skin surface. Serial hot and humid climate induces dehydration which interferes heat pump-out from the body. Heart dysfunction is the third factor to rise body temperature. Hyperthermia and hypo-perfusion caused by dehydration and heart failure deteriorate specific organ functions, i.e. central nervous system, liver and renal functions and coagulation system. Disseminated intravascular coagulopathy is one of the standard indicators of severity and mortality of heat stroke.

Smart and functional polymer materials for smart and functional microfluidic instruments

NASA Astrophysics Data System (ADS)

Gray, Bonnie L.

2014-04-01

As microfluidic systems evolve from "chip-in-the-lab" to true portable lab-on-a-chip (LoC) or lab-in-a-package (LiP) microinstrumentation, there is a need for increasingly miniaturized sensors, actuators, and integration/interconnect technologies with high levels of functionality and self-direction. Furthermore, as microfluidic instruments are increasingly realized in polymer-based rather than glass- or silicon- based platforms, there is a need to realize these highly functional components in materials that are polymer-compatible. Polymers that are altered to possess basic functionality, and even higher-functioning "smart" polymer materials, may help to realize high-functioning and selfdirecting portable microinstrumentation. Stimuli-responsive hydrogels have been recognized for over a decade as beneficial to the development of smart microfluidics systems and instrumentation. In addition, functional materials such as conductive and magnetic composite polymers are being increasingly employed to push microfluidics systems to greater degrees of functionality, portability, and/or flexibility for wearable/implantable systems. Functional and smart polymer materials can be employed to realize electrodes, electronic routing, heaters, mixers, valves, pumps, sensors, and interconnect structures in polymer-based microfluidic systems. Stimuli for such materials can be located on-chip or in a small package, thus greatly increasing the degree of portability and the potential for mechanical flexibility of such systems. This paper will examine the application of functional polymer materials to the development of high-functioning microfluidics instruments with a goal towards self-direction.

Concurrent Formation of Carbon–Carbon Bonds and Functionalized Graphene by Oxidative Carbon-Hydrogen Coupling Reaction

PubMed Central

Morioku, Kumika; Morimoto, Naoki; Takeuchi, Yasuo; Nishina, Yuta

2016-01-01

Oxidative C–H coupling reactions were conducted using graphene oxide (GO) as an oxidant. GO showed high selectivity compared with commonly used oxidants such as (diacetoxyiodo) benzene and 2,3-dichloro-5,6-dicyano-p-benzoquinone. A mechanistic study revealed that radical species contributed to the reaction. After the oxidative coupling reaction, GO was reduced to form a material that shows electron conductivity and high specific capacitance. Therefore, this system could concurrently achieve two important reactions: C–C bond formation via C–H transformation and production of functionalized graphene. PMID:27181191

Turboelectric Aircraft Drive Key Performance Parameters and Functional Requirements

NASA Technical Reports Server (NTRS)

Jansen, Ralph H.; Brown, Gerald V.; Felder, James L.; Duffy, Kirsten P.

2016-01-01

The purpose of this paper is to propose specific power and efficiency as the key performance parameters for a turboelectric aircraft power system and investigate their impact on the overall aircraft. Key functional requirements are identified that impact the power system design. Breguet range equations for a base aircraft and a turboelectric aircraft are found. The benefits and costs that may result from the turboelectric system are enumerated. A break-even analysis is conducted to find the minimum allowable electric drive specific power and efficiency that can preserve the range, initial weight, operating empty weight, and payload weight of the base aircraft.

Turboelectric Aircraft Drive Key Performance Parameters and Functional Requirements

NASA Technical Reports Server (NTRS)

Jansen, Ralph; Brown, Gerald V.; Felder, James L.; Duffy, Kirsten P.

2015-01-01

The purpose of this presentation is to propose specific power and efficiency as the key performance parameters for a turboelectric aircraft power system and investigate their impact on the overall aircraft. Key functional requirements are identified that impact the power system design. Breguet range equations for a base aircraft and a turboelectric aircraft are found. The benefits and costs that may result from the turboelectric system are enumerated. A break-even analysis is conducted to find the minimum allowable electric drive specific power and efficiency that can preserve the range, initial weight, operating empty weight, and payload weight of the base aircraft.

Turboelectric Aircraft Drive Key Performance Parameters and Functional Requirements

NASA Technical Reports Server (NTRS)

Jansen, Ralph H.; Brown, Gerald V.; Felder, James L.; Duffy, Kirsten P.

2015-01-01

The purpose of this paper is to propose specific power and efficiency as the key performance parameters for a turboelectric aircraft power system and investigate their impact on the overall aircraft. Key functional requirements are identified that impact the power system design. Breguet range equations for a base aircraft and a turboelectric aircraft are found. The benefits and costs that may result from the turboelectric system are enumerated. A break-even analysis is conducted to find the minimum allowable electric drive specific power and efficiency that can preserve the range, initial weight, operating empty weight, and payload weight of the base aircraft.

Thermal Conductivity of Advanced Ceramic Thermal Barrier Coatings Determined by a Steady-state Laser Heat-flux Approach

NASA Technical Reports Server (NTRS)

Zhu, Dong-Ming; Miller, Robert A.

2004-01-01

The development of low conductivity and high temperature capable thermal barrier coatings requires advanced testing techniques that can accurately and effectively evaluate coating thermal conductivity under future high-performance and low-emission engine heat-flux conditions. In this paper, a unique steady-state CO2 laser (wavelength 10.6 microns) heat-flux approach is described for determining the thermal conductivity and conductivity deduced cyclic durability of ceramic thermal and environmental barrier coating systems at very high temperatures (up to 1700 C) under large thermal gradients. The thermal conductivity behavior of advanced thermal and environmental barrier coatings for metallic and Si-based ceramic matrix composite (CMC) component applications has also been investigated using the laser conductivity approach. The relationships between the lattice and radiation conductivities as a function of heat flux and thermal gradient at high temperatures have been examined for the ceramic coating systems. The steady-state laser heat-flux conductivity approach has been demonstrated as a viable means for the development and life prediction of advanced thermal barrier coatings for future turbine engine applications.

High Altitude Long Endurance (HALE) Unmanned Aircraft System (UAS): Pilot Knowledge, Skills and Abilities

NASA Technical Reports Server (NTRS)

2005-01-01

This report summarizes the initial work accomplished by the ACCESS 5 Human System Integration (HSI) team to identify Unmanned Aircraft System (UAS) Pilot Knowledge, Skill and Ability (KSA), Training and Medical requirements. To derive this information the following tasks were accomplished: a) Mission and Function analyses were performed; b) Applicable FARs and FAA Advisory Circulars (ACs) were reviewed; c) Meetings were conducted with NASA and FAA Human Factors personnel; d) Surveys were completed by ACCESS 5 HSI Working group UA Pilots; e) Coordination meetings were conducted with the ACCESS 5 Policy IPT. The results of these efforts were used to develop a summary of the current qualifications. for an individual to function as a Pilot In Command (PIC) for UAs currently flown by UNITE companies, to develop preliminary Pilot KSAs for each phase of flight, and to delineate preliminary Pilot Training and Medical requirements. These results are to be provided to the Policy IPT to support their development of recommendations for UA Pilot Rating Criteria, training and medical qualifications. It is expected that the initially an instrument rated pilot will be required to serve as the PIC. However, as operational experience is gained, and automation is applied to accomplish various system functions, it is expected that pilot rating criteria could be lessened.

Functional requirements for onboard management of space shuttle consumables, volume 1

NASA Technical Reports Server (NTRS)

Graf, P. J.; Herwig, H. A.; Neel, L. W.

1973-01-01

A study was conducted to determine the functional requirements for onboard management of space shuttle consumables. A generalized consumable management concept was developed for application to advanced spacecraft. The subsystems and related consumables selected for inclusion in the consumables management system are: (1) propulsion, (2) power generation, and (3) environmental and life support.

Proceedings from the Workshop on Nanoscience for the Soldier

DTIC Science & Technology

2001-02-09

Affordable, Durable, Flexible Enabled by Active Devices Miniature Ventilation, Cooling & Heating Multi-Functional, Hybrid Power Embedded Micro-Sensors...functional element • Rifle protection, back support & comfort, load bearing stability & interfaces with family of back packs & cooling/ heating system...Integrated physiological & medical sensors – Conductive or Fiber Optic fibers for Data & Power Distribution – Carbon Fiber Heating at wrists

Graphics enhanced computer emulation for improved timing-race and fault tolerance control system analysis. [of Centaur liquid-fuel booster

NASA Technical Reports Server (NTRS)

Szatkowski, G. P.

1983-01-01

A computer simulation system has been developed for the Space Shuttle's advanced Centaur liquid fuel booster rocket, in order to conduct systems safety verification and flight operations training. This simulation utility is designed to analyze functional system behavior by integrating control avionics with mechanical and fluid elements, and is able to emulate any system operation, from simple relay logic to complex VLSI components, with wire-by-wire detail. A novel graphics data entry system offers a pseudo-wire wrap data base that can be easily updated. Visual subsystem operations can be selected and displayed in color on a six-monitor graphics processor. System timing and fault verification analyses are conducted by injecting component fault modes and min/max timing delays, and then observing system operation through a red line monitor.

The Viking Orbiter and its Mariner inheritance

NASA Technical Reports Server (NTRS)

Wolfe, A. E.; Norris, H. W.

1975-01-01

The orbiter system of the Viking spacecraft performs the functions of transporting the lander into orbit around Mars, surveying the proposed landing sites, relaying lander data to earth, and conducting independent scientific observations of Mars. The orbiter system is a semiautomatic, solar-powered, triaxially stabilized platform capable of making trajectory corrections and communicating with earth on S-band. Its instruments for visual imaging, detecting water vapor, and thermal mapping are mounted on a separate two-degree-of-freedom scan platform. Radio science is conducted at three frequencies, using the main S-band system, a separate X-band derived from the S-band, and the UHF one-way link with the lander.

Effect of stocking rate on growing juvenile sunshine bass in an outdoor biofloc production system: study shows potential to intensify production of sunshine bass fingerlings

USDA-ARS?s Scientific Manuscript database

A dose–response study was conducted in an outdoor biofloc system to begin quantifying the stocking rate production function for sunshine bass advanced fingerlings. Results showed the potential of the outdoor biofloc system to intensify production of advanced sunshine bass fingerlings, but feed cons...

Total Integrated Library Information System. Part 2. A Report on the Specific Design Phase: Identification and Evaluation.

ERIC Educational Resources Information Center

Meyer, R. W.; Alexander, George

This study, conducted to determine which automated system would be the most appropriate to replicate or install at Clemson University to support the users of the library, screened 29 library automation systems to determine those most adaptable to Clemson's needs. In-depth comparisons were made with regard to functions available, features, start up…

Theory of tunneling spectroscopy for chiral topological superconductors

NASA Astrophysics Data System (ADS)

Ii, Akihiro; Yamakage, Ai; Yada, Keiji; Sato, Masatoshi; Tanaka, Yukio

2012-11-01

We study the charge conductance of an interface between a normal metal and a superconducting quantum anomalous Hall system, based on the recursive Green's function. The angle-resolved conductance γ(ky,eV) with momentum ky parallel to the interface and bias voltage V shows a rich structure depending on the Chern number N of the system. We find that when the bias voltage is tuned to the energy dispersion of the edge mode, eV=Eedge(ky), the angle-resolved conductance γ(ky,Eedge(ky)) shows a pronounced even-odd effect; the conductance vanishes for N=0 or 2, while it takes the universal value 2e2/h for N=1. In particular, in the N=2 phase, we find that the conductance γ(ky,Eedge(ky)) becomes 0 due to the interference of two degenerate Majorana edge modes, although the corresponding surface spectral weight remains nonzero.

Electronic tunneling through a potential barrier on the surface of a topological insulator

NASA Astrophysics Data System (ADS)

Zhou, Benliang; Zhou, Benhu; Zhou, Guanghui

2016-12-01

We investigate the tunneling transport for electrons on the surface of a topological insulator (TI) through an electrostatic potential barrier. By using the Dirac equation with the continuity conditions for all segments of wave functions at the interfaces between regions inside and outside the barrier, we calculate analytically the transmission probability and conductance for the system. It is demonstrated that, the Klein paradox can also been observed in the system same as in graphene system. Interestingly, the conductance reaches the minimum value when the incident electron energy is equal to the barrier strength. Moreover, with increasing barrier width, the conductance turns up some tunneling oscillation peaks, and larger barrier strength can cause lower conductance, shorter period but larger oscillation amplitude. The oscillation amplitude decreases as the barrier width increases, which is similar as that of the system consisting of the compressive uniaxial strain applied on a TI, but somewhat different from that of graphene system where the oscillation amplitude is a constant. The findings here imply that an electrostatic barrier can greatly influence the electron tunneling transport of the system, and may provide a new way to realize directional filtering of electrons.

Scaling-up health information systems to improve HIV treatment: An assessment of initial patient monitoring systems in Mozambique.

PubMed

Hochgesang, Mindy; Zamudio-Haas, Sophia; Moran, Lissa; Nhampossa, Leopoldo; Packel, Laura; Leslie, Hannah; Richards, Janise; Shade, Starley B

2017-01-01

The rapid scale-up of HIV care and treatment in resource-limited countries requires concurrent, rapid development of health information systems to support quality service delivery. Mozambique, a country with an 11.5% prevalence of HIV, has developed nation-wide patient monitoring systems (PMS) with standardized reporting tools, utilized by all HIV treatment providers in paper or electronic form. Evaluation of the initial implementation of PMS can inform and strengthen future development as the country moves towards a harmonized, sustainable health information system. This assessment was conducted in order to 1) characterize data collection and reporting processes and PMS resources available and 2) provide evidence-based recommendations for harmonization and sustainability of PMS. This baseline assessment of PMS was conducted with eight non-governmental organizations that supported the Ministry of Health to provide 90% of HIV care and treatment in Mozambique. The study team conducted structured and semi-structured surveys at 18 health facilities located in all 11 provinces. Seventy-nine staff were interviewed. Deductive a priori analytic categories guided analysis. Health facilities have implemented paper and electronic monitoring systems with varying success. Where in use, robust electronic PMS facilitate facility-level reporting of required indicators; improve ability to identify patients lost to follow-up; and support facility and patient management. Challenges to implementation of monitoring systems include a lack of national guidelines and norms for patient level HIS, variable system implementation and functionality, and limited human and infrastructure resources to maximize system functionality and information use. This initial assessment supports the need for national guidelines to harmonize, expand, and strengthen HIV-related health information systems. Recommendations may benefit other countries with similar epidemiologic and resource-constrained environments seeking to improve PMS implementation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Electrical conductivity of Icelandic deep geothermal reservoirs: insight from HT-HP laboratory experiments

NASA Astrophysics Data System (ADS)

Nono, Franck; Gibert, Benoit; Loggia, Didier; Parat, Fleurice; Azais, Pierre; Cichy, Sarah

2016-04-01

Although the Icelandic geothermal system has been intensively investigated over the years, targeting increasingly deeper reservoirs (i.e. under supercritical conditions) requires a good knowledge of the behaviour of physical properties of the host rock in order to better interpret large scale geophysical observations. In particular, the interpretation of deep electrical soundings remains controversial as only few studies have investigated the influence of altered minerals and pore fluid properties on electrical properties of rocks at high temperature and pressure. In this study, we investigate the electrical conductivity of drilled samples from different Icelandic geothermal fields at elevated temperature, confining pressure and pore pressure conditions (100°C < T < 600°C, confining pressure up to 100 MPa and pore pressure up to 35 MPa). The investigated rocks are composed of hyaloclastites, dolerites and basalts taken from depths of about 800 m for the hyaloclastites, to almost 2500 m for the dolerites. They display different porosity structures, from vuggy and intra-granular to micro-cracked porosities, and have been hydrothermally alterated in the chlorite to amphibolite facies. Electrical conductivity measurements are first determined at ambient conditions as a function of pore fluid conductivity in order to establish their relationships with lithology and pore space topology, prior to the high pressure and temperature measurements. Cementation factor varies from 1.5 for the dolerites to 2.83 for the basalt, reflecting changes in the shape of the conductive channels. The surface conductivities, measured at very low fluid conductivity, increases with the porosity and is correlated with the cation exchange capacity. At high pressure and temperature, we used the two guard-ring electrodes system. Measurements have been performed in dry and saturated conditions as a function of temperature and pore pressure. The supercritical conditions have been investigated and temperature cycles have been performed systematically. Dry electrical conductivity measurements show for most of the samples irreversible changes when temperatures exceed 500°C. These changes are interpreted as destabilization/dehydration of alteration minerals that could lead to the presence of a conductive fluid phase in the samples. Very low and high salinity (NaCl) electrical conductivity measurements have been performed as a function of temperature. At supercritical conditions, electrical conductivity at low salinity is not pore pressure dependent and surface conduction is preponderant. At saturated conditions, the rock's electrical conductivity increases linearly (as a function of T-1) until 350°C. Above 350°C, the conductivity decreases. All rock types exhibit the same increasing rate. This work was funded by the of the EC project IMAGE (Integrated Methods for Advanced Geothermal Exploration, grant agreement No. 608553).

Operando Multi-modal Synchrotron Investigation for Structural and Chemical Evolution of Cupric Sulfide (CuS) Additive in Li-S battery

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

Sun, Ke; Zhao, Chonghang; Lin, Cheng-Hung

Conductive metal sulfides are promising multi-functional additives for future lithium-sulfur (Li-S) batteries. These can increase the sulfur cathode’s electrical conductivity to improve the battery’s power capability, as well as contribute to the overall cell-discharge capacity. This multi-functional electrode design showed initial promise; however, complicated interactions at the system level are accompanied by some detrimental side effects. The metal sulfide additives with a chemical conversion as the reaction mechanism, e.g., CuS and FeS 2, can increase the theoretical capacity of the Li-S system. However, these additives may cause undesired parasitic reactions, such as the dissolution of the additive in the electrolyte.more » Studying such complex reactions presents a challenge because it requires experimental methods that can track the chemical and structural evolution of the system during an electrochemical process. To address the fundamental mechanisms in these systems, we employed an operando multimodal x-ray characterization approach to study the structural and chemical evolution of the metal sulfide—utilizing powder diffraction and fluorescence imaging to resolve the former and absorption spectroscopy the latter—during lithiation and de-lithiation of a Li-S battery with CuS as the multi-functional cathode additive. The resulting elucidation of the structural and chemical evolution of the system leads to a new description of the reaction mechanism.« less

Operando Multi-modal Synchrotron Investigation for Structural and Chemical Evolution of Cupric Sulfide (CuS) Additive in Li-S battery

DOE PAGES

Sun, Ke; Zhao, Chonghang; Lin, Cheng-Hung; ...

2017-10-11

Conductive metal sulfides are promising multi-functional additives for future lithium-sulfur (Li-S) batteries. These can increase the sulfur cathode’s electrical conductivity to improve the battery’s power capability, as well as contribute to the overall cell-discharge capacity. This multi-functional electrode design showed initial promise; however, complicated interactions at the system level are accompanied by some detrimental side effects. The metal sulfide additives with a chemical conversion as the reaction mechanism, e.g., CuS and FeS 2, can increase the theoretical capacity of the Li-S system. However, these additives may cause undesired parasitic reactions, such as the dissolution of the additive in the electrolyte.more » Studying such complex reactions presents a challenge because it requires experimental methods that can track the chemical and structural evolution of the system during an electrochemical process. To address the fundamental mechanisms in these systems, we employed an operando multimodal x-ray characterization approach to study the structural and chemical evolution of the metal sulfide—utilizing powder diffraction and fluorescence imaging to resolve the former and absorption spectroscopy the latter—during lithiation and de-lithiation of a Li-S battery with CuS as the multi-functional cathode additive. The resulting elucidation of the structural and chemical evolution of the system leads to a new description of the reaction mechanism.« less

Generative mechanistic explanation building in undergraduate molecular and cellular biology

NASA Astrophysics Data System (ADS)

Southard, Katelyn M.; Espindola, Melissa R.; Zaepfel, Samantha D.; Bolger, Molly S.

2017-09-01

When conducting scientific research, experts in molecular and cellular biology (MCB) use specific reasoning strategies to construct mechanistic explanations for the underlying causal features of molecular phenomena. We explored how undergraduate students applied this scientific practice in MCB. Drawing from studies of explanation building among scientists, we created and applied a theoretical framework to explore the strategies students use to construct explanations for 'novel' biological phenomena. Specifically, we explored how students navigated the multi-level nature of complex biological systems using generative mechanistic reasoning. Interviews were conducted with introductory and upper-division biology students at a large public university in the United States. Results of qualitative coding revealed key features of students' explanation building. Students used modular thinking to consider the functional subdivisions of the system, which they 'filled in' to varying degrees with mechanistic elements. They also hypothesised the involvement of mechanistic entities and instantiated abstract schema to adapt their explanations to unfamiliar biological contexts. Finally, we explored the flexible thinking that students used to hypothesise the impact of mutations on multi-leveled biological systems. Results revealed a number of ways that students drew mechanistic connections between molecules, functional modules (sets of molecules with an emergent function), cells, tissues, organisms and populations.

Magneto-conductance fingerprints of purely quantum states in the open quantum dot limit

NASA Astrophysics Data System (ADS)

Mendoza, Michel; Ujevic, Sebastian

2012-06-01

We present quantum magneto-conductance simulations, at the quantum low energy condition, to study the open quantum dot limit. The longitudinal conductance G(E,B) of spinless and non-interacting electrons is mapped as a function of the magnetic field B and the energy E of the electrons. The quantum dot linked to the semi-infinite leads is tuned by quantum point contacts of variable width w. We analyze the transition from a quantum wire to an open quantum dot and then to an effective closed system. The transition, as a function of w, occurs in the following sequence: evolution of quasi-Landau levels to Fano resonances and quasi-bound states between the quasi-Landau levels, followed by the formation of crossings that evolve to anti-crossings inside the quasi-Landau level region. After that, Fano resonances are created between the quasi-Landau states with the final generation of resonant tunneling peaks. By comparing the G(E,B) maps, we identify the closed and open-like limits of the system as a function of the applied magnetic field. These results were used to build quantum openness diagrams G(w,B). Also, these maps allow us to determine the w-limit value from which we can qualitatively relate the closed system properties to the open one. The above analysis can be used to identify single spinless particle effects in experimental measurements of the open quantum dot limit.

Flow and Transport in Highly Heterogeneous Porous Formations: Numerical Experiments Performed Using the Analytic Element Method

NASA Astrophysics Data System (ADS)

Jankovic, I.

2002-05-01

Flow and transport in porous formations are analyzed using numerical simulations. Hydraulic conductivity is treated as a spatial random function characterized by a probability density function and a two-point covariance function. Simulations are performed for a multi-indicator conductivity structure developed by Gedeon Dagan (personal communication). This conductivity structure contains inhomogeneities (inclusions) of elliptical and ellipsoidal geometry that are embedded in a homogeneous background. By varying the distribution of sizes and conductivities of inclusions, any probability density function and two-point covariance may be reproduced. The multi-indicator structure is selected since it yields simple approximate transport solutions (Aldo Fiori, personal communication) and accurate numerical solutions (based on the Analytic Element Method). The dispersion is examined for two conceptual models. Both models are based on the multi-indicator conductivity structure. The first model is designed to examine dispersion in aquifers with continuously varying conductivity. The inclusions in this model cover as much area/volume of the porous formation as possible. The second model is designed for aquifers that contain clay/sand/gravel lenses embedded in otherwise homogeneous background. The dispersion in both aquifer types is simulated numerically. Simulation results are compared to those obtained using simple approximate solutions. In order to infer transport statistics that are representative of an infinite domain using the numerical experiments, the inclusions are placed in a domain that was shaped as a large ellipse (2D) and a large spheroid (3D) that were submerged in an unbounded homogeneous medium. On a large scale, the large body of inclusions behaves like a single large inhomogeneity. The analytic solution for a uniform flow past the single inhomogeneity of such geometry yields uniform velocity inside the domain. The velocity differs from that at infinity and can be used to infer the effective conductivity of the medium. As many as 100,000 inhomogeneities are placed inside the domain for 2D simulations. Simulations in 3D were limited to 50,000 inclusions. A large number of simulations was conducted on a massively parallel supercomputer cluster at the Center for Computational Research, University at Buffalo. Simulations range from mildly heterogeneous formations to highly heterogeneous formations (variance of the logarithm of conductivity equal to 10) and from sparsely populated systems to systems where inhomogeneities cover 95% of the volume. Particles are released and tracked inside the core of constant mean velocity. Following the particle tracking, various medium, flow, and transport statistics are computed. These include: spatial moments of particle positions, probability density function of hydraulic conductivity and each component of velocity, their two-point covariance function in the direction of flow and normal to it, covariance of Lagrangean velocities, and probability density function of travel times to various break-through locations. Following the analytic nature of the flow solution, all the results are presented in dimensionless forms. For example, the dispersion coefficients are made dimensionless with respect to the mean velocity and size of inhomogeneities. Detailed results will be presented and compared to well known first-order results and the results that are based on simple approximate transport solutions of Aldo Fiori.

Department of Defense Status of Year 2000 Efforts. 11th Quarterly Progress Report

DTIC Science & Technology

1999-11-15

Duplicate systems corrected when all Intelligence mission critical systems were folded into the unclassified OSD database to allow for complete tracking in...one database. - 2 Two Intelligence Systems that were scheduled to be terminated or replaced that have been reclassified to non-mission...National Communication System participated in the Federal Sector Group meetings and assessed our role in the functional testing. Industry conducted

Problems in the long-term storage of data obtained from scientific space experiments

NASA Technical Reports Server (NTRS)

Zlotin, G. N.; Khovanskiy, Y. D.

1975-01-01

It is shown that long-term data storage systems can be achieved when the system which organizes and conducts the scientific space experiments is equipped with a specialized subsystem: the information filing system. Its main functions are described along with the necessity of stage-by-stage development and compatibility with the data processing systems. The requirements for long-term data storage media are discussed.

[A study of factors related to activities of daily living (ADL) of the elderly receiving in-home service longitudinal study using functional independence measures].

PubMed

Suzuki, Ikuko; Yanagi, Hisako; Tomura, Shigeo

2007-02-01

We conducted a longitudinal study using Functional Independence Measures to clarify factor related to independence of activities of daily living of elderly receiving in-home service under the long-term care insurance system Fifty-four elderly users of the in-home service of Ibaraki Prefecture assented to participate in this study and were analyzed. A researcher conducted survey at the baseline and after follow-up by visiting the elderly at each home. The evaluation standards used here were the Japanese version of Functional Independence Measure (FIM), Mini-Mental State Examination (MMSE), and Geriatric Depression Scale (GDS-15). The FIM score (mean+/-SD) was decreased 83.6+/-36.4 to 81.7+/-37.4 during the 112+/-22.2 day follow up period. Thirty-nine elderly demonstrated improvement or no change in FIM and 15 had declining scores. To clarify independent factors related to FIM change, we conducted a step-wise multifactor logistic regression analysis, and the results suggested importance for "in-home service availability" and "home care period less than one year". Our study suggested that it is important for maintenance or improvement of ADL in home care elderly to provide sufficient home .care services from the beginning under the long-term care insurance system.

Estrogen-Related Receptor α (ERRα) and ERRγ Are Essential Coordinators of Cardiac Metabolism and Function

PubMed Central

Wang, Ting; McDonald, Caitlin; Petrenko, Nataliya B.; Leblanc, Mathias; Wang, Tao; Giguere, Vincent; Evans, Ronald M.; Patel, Vickas V.

2015-01-01

Almost all cellular functions are powered by a continuous energy supply derived from cellular metabolism. However, it is little understood how cellular energy production is coordinated with diverse energy-consuming cellular functions. Here, using the cardiac muscle system, we demonstrate that nuclear receptors estrogen-related receptor α (ERRα) and ERRγ are essential transcriptional coordinators of cardiac energy production and consumption. On the one hand, ERRα and ERRγ together are vital for intact cardiomyocyte metabolism by directly controlling expression of genes important for mitochondrial functions and dynamics. On the other hand, ERRα and ERRγ influence major cardiomyocyte energy consumption functions through direct transcriptional regulation of key contraction, calcium homeostasis, and conduction genes. Mice lacking both ERRα and cardiac ERRγ develop severe bradycardia, lethal cardiomyopathy, and heart failure featuring metabolic, contractile, and conduction dysfunctions. These results illustrate that the ERR transcriptional pathway is essential to couple cellular energy metabolism with energy consumption processes in order to maintain normal cardiac function. PMID:25624346

A theoretical study for electronic and transport properties of covalent functionalized MoS2 monolayer

NASA Astrophysics Data System (ADS)

Gao, Lijuan; Yang, Zhao-Di; Zhang, Guiling

2017-06-01

The geometries, electronic and electron transport properties of a series of functionalized MoS2 monolayers were investigated using density-functional theory (DFT) and the non-equilibrium Green's function (NEGF) methods. n-Propyl, n-trisilicyl, phenyl, p-nitrophenyl and p-methoxyphenyl are chosen as electron-donating groups. The results show covalent functionalization with electron-donating groups could make a transformation from typical semiconducting to metallic properties for appearance of midgap level across the Fermi level (Ef). The calculations of transport properties for two-probe devices indicate that conductivities of functionalized systems are obviously enhanced relative to pristine MoS2 monolayer. Grafted groups contribute to the major transport path and play an important role in enhancing conductivity. The NDR effect is found. The influence of grafted density is also studied. Larger grafted density leads to wider bandwidth of midgap level, larger current response of I-V curves and larger current difference between peak and valley.

On the probability of violations of Fourier's law for heat flow in small systems observed for short times

NASA Astrophysics Data System (ADS)

Evans, Denis J.; Searles, Debra J.; Williams, Stephen R.

2010-01-01

We study the statistical mechanics of thermal conduction in a classical many-body system that is in contact with two thermal reservoirs maintained at different temperatures. The ratio of the probabilities, that when observed for a finite time, the time averaged heat flux flows in and against the direction required by Fourier's Law for heat flow, is derived from first principles. This result is obtained using the transient fluctuation theorem. We show that the argument of that theorem, namely, the dissipation function is, close to equilibrium, equal to a microscopic expression for the entropy production. We also prove that if transient time correlation functions of smooth zero mean variables decay to zero at long times, the system will relax to a unique nonequilibrium steady state, and for this state, the thermal conductivity must be positive. Our expressions are tested using nonequilibrium molecular dynamics simulations of heat flow between thermostated walls.

Evaluation of Thermal Protection Tile Transmissibility for Ground Vibration Test

NASA Technical Reports Server (NTRS)

Chung, Y. T.; Fowler, Samuel B.; Lo, Wenso; Towner, Robert

2005-01-01

Transmissibility analyses and tests were conducted on a composite panel with thermal protection system foams to evaluate the quality of the measured frequency response functions. Both the analysis and the test results indicate that the vehicle dynamic responses are fully transmitted to the accelerometers mounted on the thermal protection system in the normal direction below a certain frequency. In addition, the in-plane motions of the accelerometer mounted on the top surface of the thermal protection system behave more actively than those on the composite panel due to the geometric offset of the accelerometer from the panel in the test set-up. The transmissibility tests and analyses show that the frequency response functions measured from the accelerometers mounted on the TPS will provide accurate vehicle responses below 120 Hz for frequency and mode shape identification. By confirming that accurate dynamic responses below a given frequency can be obtained, this study increases the confidence needed for conducting the modal testing, model correlation, and model updating for a vehicle installed with TPS. '

PERCEPTUAL SYSTEMS IN READING--THE PREDICTION OF A TEMPORAL EYE-VOICE SPAN CONSTANT. PAPER.

ERIC Educational Resources Information Center

GEYER, JOHN JACOB

A STUDY WAS CONDUCTED TO DELINEATE HOW PERCEPTION OCCURS DURING ORAL READING. FROM AN ANALYSIS OF CLASSICAL AND MODERN RESEARCH, A HEURISTIC MODEL WAS CONSTRUCTED WHICH DELINEATED THE DIRECTLY INTERACTING SYSTEMS POSTULATED AS FUNCTIONING DURING ORAL READING. THE MODEL AS OUTLINED WAS DIFFERENTIATED LOGICALLY INTO THREE MAJOR PROCESSING…

Work-Based Mentor Training for Pennsylvania's School-to-Work System. Final Report.

ERIC Educational Resources Information Center

Walker, Thomas J.; And Others

Three Pennsylvania universities focused on defining the functional role and identifying the training needs of work-based mentors for Pennsylvania's system of school-to-work transition, in order to design a training protocol. Interviews were conducted with 81 experienced employees concerning their view of the mentoring role and the activities that…

Bandgap and pseudohelicity effects over conductance in gapped graphene junctures

NASA Astrophysics Data System (ADS)

Navarro-Giraldo, J. A.; Quimbay, C. J.

2018-07-01

We study the conductance in gapped single-layer graphene junctures as a function of bangap, pseudohelicity and charge carriers density. To do it, we first calculate the transmission coefficients of massive charge carries for p–n and n–p–n junctures of gapped single-layer graphene. Next, we calculate the conductance for these two systems using the Landauer formula. Only for the p–n juncture case and non-zero bandgap values, we find the existence of a contribution to the conductance from pseudohelicity inversion states, which is small compared to the contribution from pseudohelicity conservation states. Also, we find for both type of junctures that there exists a window of charge carriers densities values where the conductance is zero (conductance gap), in such a way that the size of this window depends on the squared of the bandgap. We observe that the existence of a bandgap in the system leads to valley mixing and this fact could be useful for the future design of devices based on single-layer graphene.

Andreev rectifier: A nonlocal conductance signature of topological phase transitions

NASA Astrophysics Data System (ADS)

Rosdahl, T. Ö.; Vuik, A.; Kjaergaard, M.; Akhmerov, A. R.

2018-01-01

The proximity effect in hybrid superconductor-semiconductor structures, crucial for realizing Majorana edge modes, is complicated to control due to its dependence on many unknown microscopic parameters. In addition, defects can spoil the induced superconductivity locally in the proximitized system, which complicates measuring global properties with a local probe. We show how to use the nonlocal conductance between two spatially separated leads to probe three global properties of a proximitized system: the bulk superconducting gap, the induced gap, and the induced coherence length. Unlike local conductance spectroscopy, nonlocal conductance measurements distinguish between nontopological zero-energy modes localized around potential inhomogeneities, and true Majorana edge modes that emerge in the topological phase. In addition, we find that the nonlocal conductance is an odd function of bias at the topological phase transition, acting as a current rectifier in the low-bias limit. More generally, we identify conditions for crossed Andreev reflection to dominate the nonlocal conductance and show how to design a Cooper pair splitter in the open regime.

Mars Exploration Rover Mission: Entry, Descent, and Landing System Validation

NASA Technical Reports Server (NTRS)

Mitcheltree, Robert A.; Lee, Wayne; Steltzner, Adam; SanMartin, Alejanhdro

2004-01-01

System validation for a Mars entry, descent, and landing system is not simply a demonstration that the electrical system functions in the associated environments. The function of this system is its interaction with the atmospheric and surface environment. Thus, in addition to traditional test-bed, hardware-in-the-loop, testing, a validation program that confirms the environmental interaction is required. Unfortunately, it is not possible to conduct a meaningful end-to-end test of a Mars landing system on Earth. The validation plan must be constructed from an interconnected combination of simulation, analysis and test. For the Mars Exploration Rover mission, this combination of activities and the logic of how they combined to the system's validation was explicitly stated, reviewed, and tracked as part of the development plan.

Studies of Cell-Mediated Immunity Against Immune Disorders Using Synthetic Peptides and Rotating Bioreactor System

NASA Technical Reports Server (NTRS)

Sastry, Jagannadha K.

1998-01-01

We conducted a series of experiments using mouse immune-precursor cells, and observed that bioreactor culturing results in the loss of antigen-specific cytotoxic T lymphocyte (CTL) function. The reason for the abrogation of CTL function is microgravity conditions in the bioreactor, but not the antigen per se or its MHC restriction. Similarly, we observed that allostimulation of human PBMC in the bioreactor, but not in the T flask, resulted in the blunting of both allo-CTL function and the NK activity, indicating that the microgravity-associated functional defects are not unique to the mouse system. These results provide further confirmation to the microgravity-associated immune dysfunction, and constitute ground-based confirmatory data for those related to space-travel.

An overview of Japanese CELSS research activities

NASA Technical Reports Server (NTRS)

Nitta, Keiji

1987-01-01

Development of Controlled Ecological Life Support System (CELSS) technology is inevitable for future long duration stays of human beings in space, for lunar base construction and for manned Mars flight programs. CELSS functions can be divided into 2 categories, Environmental Control and Material Recycling. Temperature, humidity, total atmospheric pressure and partial pressure of oxygen and carbon dioxide, necessary for all living things, are to be controlled by the environment control function. This function can be performed by technologies already developed and used as the Environment Control Life Support System (ECLSS) of Space Shuttle and Space Station. As for material recycling, matured technologies have not yet been established for fully satisfying the specific metabolic requirements of each living thing including human beings. Therefore, research activities for establishing CELSS technology should be focused on material recycling technologies using biological systems such as plants and animals and physico-chemical systems, for example, a gas recycling system, a water purifying and recycling system and a waste management system. Japanese research activities were conducted and will be continued accordingly.

Signatures of spin-orbital states of t2g 2 system in optical conductivity: R VO3 (R =Y and La)

NASA Astrophysics Data System (ADS)

Kim, Minjae

2018-04-01

We investigate signatures of the spin and orbital states of R VO3 (R =Y and La) in optical conductivity using density functional theory plus dynamical mean-field theory (DFT+DMFT). From the assignment of multiplet state configurations to optical transitions, the DFT+DMFT reproduces experimental temperature-dependent evolutions of optical conductivity for both YVO3 and LaVO3. We also show that the optical conductivity is a useful quantity to probe the evolution of the orbital state even in the absence of spin order. The result provides a reference to investigate the spin and orbital states of t2g 2 vanadate systems, which is an important issue for both fundamental physics on spin and orbital states and applications of vanadates by means of orbital state control.

Natural Resource Information System. Volume 1: Overall description

NASA Technical Reports Server (NTRS)

1972-01-01

A prototype computer-based Natural Resource Information System was designed which could store, process, and display data of maximum usefulness to land management decision making. The system includes graphic input and display, the use of remote sensing as a data source, and it is useful at multiple management levels. A survey established current decision making processes and functions, information requirements, and data collection and processing procedures. The applications of remote sensing data and processing requirements were established. Processing software was constructed and a data base established using high-altitude imagery and map coverage of selected areas of SE Arizona. Finally a demonstration of system processing functions was conducted utilizing material from the data base.

Numerical aerodynamic simulation facility. Preliminary study extension

NASA Technical Reports Server (NTRS)

1978-01-01

The production of an optimized design of key elements of the candidate facility was the primary objective of this report. This was accomplished by effort in the following tasks: (1) to further develop, optimize and describe the function description of the custom hardware; (2) to delineate trade off areas between performance, reliability, availability, serviceability, and programmability; (3) to develop metrics and models for validation of the candidate systems performance; (4) to conduct a functional simulation of the system design; (5) to perform a reliability analysis of the system design; and (6) to develop the software specifications to include a user level high level programming language, a correspondence between the programming language and instruction set and outline the operation system requirements.

Nerve Conduction Through Dendrites via Proton Hopping.

PubMed

Kier, Lemont B

2017-01-01

In our previous studies of nerve conduction conducted by proton hopping, we have considered the axon, soma, synapse and the nodes of Ranvier. The role of proton hopping described the passage of information through each of these units of a typical nerve system. The synapse projects information from the axon to the dendrite and their associated spines. We have invoked the passage of protons via a hopping mechanism to illustrate the continuum of the impulse through the system, via the soma following the dendrites. This is proposed to be a continuum invoked by the proton hopping method. With the proposal of the activity through the dendrites, via proton hopping, a complete model of the nerve function is invoked. At each step to the way, a water pathway is present and is invoked in the proposed model as the carrier of the message via proton hopping. The importance of the dendrites is evident by the presence of a vast number of spines, each possessing the possibility to carry unique messages through the nervous system. With this model of the role of dendrites, functioning with the presence of proton hopping, a complete model of the nerve system is presented. The validity of this model will be available for further studies and models to assess it's validity. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Organosilicon-Based Electrolytes for Long-Life Lithium Primary Batteries

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

Fenton, Kyle R.; Nagasubramanian, Ganesan; Staiger, Chad L.

2015-09-01

This report describes advances in electrolytes for lithium primary battery systems. Electrolytes were synthesized that utilize organosilane materials that include anion binding agent functionality. Numerous materials were synthesized and tested in lithium carbon monofluoride battery systems for conductivity, impedance, and capacity. Resulting electrolytes were shown to be completely non-flammable and showed promise as co-solvents for electrolyte systems, due to low dielectric strength.

Study of solid rocket motor for space shuttle booster, volume 2, book 3, appendix A

NASA Technical Reports Server (NTRS)

1972-01-01

A systems requirements analysis for the solid propellant rocket engine to be used with the space shuttle was conducted. The systems analysis was developed to define the physical and functional requirements for the systems and subsystems. The operations analysis was performed to identify the requirements of the various launch operations, mission operations, ground operations, and logistic and flight support concepts.

Structural and Functional Hierarchy in Photosynthetic Energy Conversion—from Molecules to Nanostructures

NASA Astrophysics Data System (ADS)

Szabó, Tibor; Magyar, Melinda; Hajdu, Kata; Dorogi, Márta; Nyerki, Emil; Tóth, Tünde; Lingvay, Mónika; Garab, Győző; Hernádi, Klára; Nagy, László

2015-12-01

Basic principles of structural and functional requirements of photosynthetic energy conversion in hierarchically organized machineries are reviewed. Blueprints of photosynthesis, the energetic basis of virtually all life on Earth, can serve the basis for constructing artificial light energy-converting molecular devices. In photosynthetic organisms, the conversion of light energy into chemical energy takes places in highly organized fine-tunable systems with structural and functional hierarchy. The incident photons are absorbed by light-harvesting complexes, which funnel the excitation energy into reaction centre (RC) protein complexes containing redox-active chlorophyll molecules; the primary charge separations in the RCs are followed by vectorial transport of charges (electrons and protons) in the photosynthetic membrane. RCs possess properties that make their use in solar energy-converting and integrated optoelectronic systems feasible. Therefore, there is a large interest in many laboratories and in the industry toward their use in molecular devices. RCs have been bound to different carrier matrices, with their photophysical and photochemical activities largely retained in the nano-systems and with electronic connection to conducting surfaces. We show examples of RCs bound to carbon-based materials (functionalized and non-functionalized single- and multiwalled carbon nanotubes), transitional metal oxides (ITO) and conducting polymers and porous silicon and characterize their photochemical activities. Recently, we adapted several physical and chemical methods for binding RCs to different nanomaterials. It is generally found that the P+(QAQB)- charge pair, which is formed after single saturating light excitation is stabilized after the attachment of the RCs to the nanostructures, which is followed by slow reorganization of the protein structure. Measuring the electric conductivity in a direct contact mode or in electrochemical cell indicates that there is an electronic interaction between the protein and the inorganic carrier matrices. This can be a basis of sensing element of bio-hybrid device for biosensor and/or optoelectronic applications.

Multifunctional SA-PProDOT Binder for Lithium Ion Batteries.

PubMed

Ling, Min; Qiu, Jingxia; Li, Sheng; Yan, Cheng; Kiefel, Milton J; Liu, Gao; Zhang, Shanqing

2015-07-08

An environmentally benign, highly conductive, and mechanically strong binder system can overcome the dilemma of low conductivity and insufficient mechanical stability of the electrodes to achieve high performance lithium ion batteries (LIBs) at a low cost and in a sustainable way. In this work, the naturally occurring binder sodium alginate (SA) is functionalized with 3,4-propylenedioxythiophene-2,5-dicarboxylic acid (ProDOT) via a one-step esterification reaction in a cyclohexane/dodecyl benzenesulfonic acid (DBSA)/water microemulsion system, resulting in a multifunctional polymer binder, that is, SA-PProDOT. With the synergetic effects of the functional groups (e.g., carboxyl, hydroxyl, and ester groups), the resultant SA-PProDOT polymer not only maintains the outstanding binding capabilities of sodium alginate but also enhances the mechanical integrity and lithium ion diffusion coefficient in the LiFePO4 (LFP) electrode during the operation of the batteries. Because of the conjugated network of the PProDOT and the lithium doping under the battery environment, the SA-PProDOT becomes conductive and matches the conductivity needed for LiFePO4 LIBs. Without the need of conductive additives such as carbon black, the resultant batteries have achieved the theoretical specific capacity of LiFePO4 cathode (ca. 170 mAh/g) at C/10 and ca. 120 mAh/g at 1C for more than 400 cycles.

High-performance space shuttle auxiliary propellant valve system

NASA Technical Reports Server (NTRS)

Smith, G. M.

1973-01-01

Several potential valve closures for the space shuttle auxiliary propulsion system (SS/APS) were investigated analytically and experimentally in a modeling program. The most promising of these were analyzed and experimentally evaluated in a full-size functional valve test fixture of novel design. The engineering investigations conducted for both model and scale evaluations of the SS/APS valve closures and functional valve fixture are described. Preliminary designs, laboratory tests, and overall valve test fixture designs are presented, and a final recommended flightweight SS/APS valve design is presented.

First-principles molecular transport calculation for the benzenedithiolate molecule

NASA Astrophysics Data System (ADS)

Rumetshofer, M.; Dorn, G.; Boeri, L.; Arrigoni, E.; von der Linden, W.

2017-10-01

A first-principles approach based on density functional theory and non-equilibrium Green’s functions is used to study the molecular transport system consisting of benzenedithiolate connected with monoatomic gold and platinum electrodes. Using symmetry arguments we explain why the conductance mechanism is different for gold and platinum electrodes. We present the charge stability diagram for the benzenedithiolate connected with monoatomic platinum electrodes including many-body effects in terms of an extended Hubbard Hamiltonian and discuss how the electrodes and the many-body effects influence the transport properties of the system.

The Intrinsic Electrophysiological Properties of Mammalian Neurons: Insights into Central Nervous System Function

NASA Astrophysics Data System (ADS)

Llinas, Rodolfo R.

1988-12-01

This article reviews the electroresponsive properties of single neurons in the mammalian central nervous system (CNS). In some of these cells the ionic conductances responsible for their excitability also endow them with autorhythmic electrical oscillatory properties. Chemical or electrical synaptic contacts between these neurons often result in network oscillations. In such networks, autorhytmic neurons may act as true oscillators (as pacemakers) or as resonators (responding preferentially to certain firing frequencies). Oscillations and resonance in the CNS are proposed to have diverse functional roles, such as (i) determining global functional states (for example, sleep-wakefulness or attention), (ii) timing in motor coordination, and (iii) specifying connectivity during development. Also, oscillation, especially in the thalamo-cortical circuits, may be related to certain neurological and psychiatric disorders. This review proposes that the autorhythmic electrical properties of central neurons and their connectivity form the basis for an intrinsic functional coordinate system that provides internal context to sensory input.

Doping effects in InN/GaN short-period quantum well structures-Theoretical studies based on density functional methods

NASA Astrophysics Data System (ADS)

Strak, Pawel; Kempisty, Pawel; Sakowski, Konrad; Krukowski, Stanislaw

2014-09-01

Density functional theory studies were conducted to determine an influence of the carrier concentration on the optical and electronic properties of InN/GaN superlattice system. The oscillator strength values, energy gaps and the band profiles were obtained. The band profiles were found to be strongly affected for technically possible heavy n-type doping while for p-type doping the carrier influence, both screening and band shift, is negligible. Blue shift of the transition energy between conduction band minima and valence band maxima was observed for high concentrations of both type carriers.

Strain Modulation of Electronic and Heat Transport Properties of Bilayer Boronitrene

NASA Astrophysics Data System (ADS)

Yang, Ming; Sun, Fang-Yuan; Wang, Rui-Ning; Zhang, Hang; Tang, Da-Wei

2017-10-01

Strain engineering has been proven as an effective approach to modify electronic and thermal properties of materials. Recently, strain effects on two-dimensional materials have become important relevant topics in this field. We performed density functional theory studies on the electronic and heat transport properties of bilayer boronitrene samples under an isotropic strain. We demonstrate that the strain will reduce the band gap width but keep the band gap type robust and direct. The strain will enhance the thermal conductivity of the system because of the increase in specific heat. The thermal conductivity was studied as a function of the phonon mean-free path.

GrDHP: a general utility function representation for dual heuristic dynamic programming.

PubMed

Ni, Zhen; He, Haibo; Zhao, Dongbin; Xu, Xin; Prokhorov, Danil V

2015-03-01

A general utility function representation is proposed to provide the required derivable and adjustable utility function for the dual heuristic dynamic programming (DHP) design. Goal representation DHP (GrDHP) is presented with a goal network being on top of the traditional DHP design. This goal network provides a general mapping between the system states and the derivatives of the utility function. With this proposed architecture, we can obtain the required derivatives of the utility function directly from the goal network. In addition, instead of a fixed predefined utility function in literature, we conduct an online learning process for the goal network so that the derivatives of the utility function can be adaptively tuned over time. We provide the control performance of both the proposed GrDHP and the traditional DHP approaches under the same environment and parameter settings. The statistical simulation results and the snapshot of the system variables are presented to demonstrate the improved learning and controlling performance. We also apply both approaches to a power system example to further demonstrate the control capabilities of the GrDHP approach.

Effects of Zeeman splitting on spin transportation in a three-terminal Rashba ring under a weak magnetic field

NASA Astrophysics Data System (ADS)

Zhai, Li-Xue; Wang, Yan; An, Zhong

2018-05-01

Spin-dependent transport in one-dimensional (1D) three-terminal Rashba rings is investigated under a weak magnetic field, and we focus on the Zeeman splitting (ZS) effect. For this purpose, the interaction between the electron spin and the weak magnetic field has been treated by perturbation theory. ZS removes the spin degeneracy, and breaks both the time reversal symmetry and the spin reversal symmetry of the ring system. Consequently, all conductance zeros are lifted and turned into conductance dips. Aharonov-Bohm (AB) oscillations can be found in both branch conductances and the total conductance as a function of the magnetic field. In a relatively high magnetic field, the decoherence caused by ZS decreases the amplitude of the branch conductance and increases that of the total conductance. The results have been compared with those reported in the published literature, and a reasonable agreement is obtained. The conductance as a function of the Rashba spin-orbit coupling (RSOC) strength has also been investigated. As the RSOC strength increases, the role of ZS becomes weaker and weaker; ZS can even be neglected when B ≤ 0.1 T.

Investigation of the Effect of Mixing Methods and Chemical Treatments on the Conductivity of the CNT/PLA Based Composites

NASA Astrophysics Data System (ADS)

Talwar, Brijpal Singh

The growing popularity of Poly lactic acid (PLA) is mainly due to its biocompatibility, good mechanical properties, and its synthesis from renewable resources. PLA can be compounded with electrically conductive fillers (e.g., carbon nanotubes (CNTs)) to form conductive polymer composites (CPCs). These fillers provide conductive functionality to the composite material by forming percolation paths. Featuring very low weight densities, CPCs have the potential to replace metals in the electronic industry, if they exhibit similar electrical conductivities to that of the metals. The current challenges being faced during the mixing of CNTs in the polymer matrix are: formation of aggregates due to strong van der Waals forces and breakage of CNTs during dispersion. In this study, we compare: (1) two fabrication methods to create CPCs (i.e., solution mixing by sonication and melt extrusion) (2) effect of various CNT functionalization techniques (i.e., acid and plasma treatments) on the conductivity of CPCs and (3) effect of using binding molecules like para-phenylenediamine, that act as bridges in between the CNTs in the CPCs and its effect on the conductivity of CPCs. Such conductive composite materials find widespread technological applications which either require, or could benefit from, the ability to pattern micro-sized features in two-dimensional (2D) and three-dimensional (3D) architectures. Direct-write fabrication technique is used to realise these printed patterns, using the CPC solution as ink. First, the composites comprising of 30% PLA by weight in Dichloromethane (DCM) and CNTs in different concentrations (up to 5wt. %) are fabricated using a two-step sonication method (i.e., dissolving PLA in DCM and then dispersing the CNTs in this polymer solution). Second, CPCs are fabricated using a twin screw micro extruder operating at 180°C. To verify the effects of functionalization of the CNTs on the conductivity of composites, the CNTs are functionalized by three methods: HNO3 acid functionalization, 3:1 ratio HNO 3 + H2SO4 acid (stronger) functionalization and N2 plasma functionalization. To check the effect of amine binding molecules, HNO3 acid functionalized CNTs are treated with a mixture of para-phenylenediamine and aniline in an acidic solution. These chemically treated CNTs are then mixed with PLA to form composites. CPC fibers are drawn using the solvent-cast printing method. These fibers are tested for their electrical conductivity using the two-probe resistivity measurement method. Maximum electrical conductivity was observed in the 5wt. % CNT concentration samples at 3.97 S/m and 25.16 S/m for CPC fibers obtained via the solution blend and the extrusion methods, respectively. In the case of the functionalized CNTs, conductivity measurements show a negative effect of functionalization on the electrical properties of the CPC. While, the amine treated CNT/PLA CPC fibers show better conductivity at 4.2 S/m when compared to the untreated CNT/PLA samples manufactured using the solution mixing method. Finally, one-dimensional (1D) structures like fibres and 2D, 3D structures like single and multi-layer scaffolds were fabricated using the solvent-cast printing technique with the above manufactured CPC solutions in DCM as inks. Such conductive microstructures find their application in the electronic industry and in micro-scale systems such as pollution detection in natural environments, tissue engineering, mechanical sensors and smart devices.

Study of ultrasonic attenuation in f-electron systems in the paramagnetic limit of Coulomb interaction

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

Shadangi, Asit Ku., E-mail: asitshad@iopb.res.in; Rout, G. C., E-mail: gcr@iopb.res.in

2015-05-15

We report here a microscopic model study of ultrasonic attenuation in f-electron systems based on Periodic Anderson Model in which Coulomb interaction is considered within a mean-field approximation for a weak interaction. The Phonon is coupled to the conduction band and f-electrons. The phonon Green's function is calculated by Zubarev's technique of the Green's function method. The temperature dependent ultrasonic attenuation co-efficient is calculated from the imaginary part of the phonon self-energy in the dynamic and long wave length limit. The f-electron occupation number is calculated self-consistently in paramagnetic limit of Coulomb interaction. The effect of the Coulomb interaction onmore » ultrasonic attenuation is studied by varying the phonon coupling parameters to the conduction and f-electrons, hybridization strength, the position of f-level and the Coulomb interaction Strength. Results are discussed on the basis of experimental results.« less

Design, Qualification and Lessons Learned of the Shutter Calibration Mechanism for EnMAP Mission

NASA Astrophysics Data System (ADS)

Schmidt, Tilo; Muller, Silvio; Bergander, Arvid; Zajac, Kai; Seifart, Klaus

2015-09-01

The Shutter Calibration Mechanism (SCM) Assembly is one of three mechanisms which are developed by HTS for the EnMAP instrument in subcontract to OHB System AG Munich. EnMAP is the Environmental Mapping and Analysis Program of the German Space Agency DLR.The binary rotary encoder of the SCM using hall-effect sensors was already presented during ESMATS 2011. This paper summarizes the main functions and design features of the Hardware and focuses on qualification testing which has finished successfully in 2014. Of particular interest is the functional testing of the main drive including the precise hall-effect position sensing system and the test of the fail safe mechanism. In addition to standard test campaign required for QM also a shock emission measurement of the fail safe mechanism activation was conducted.Test conduction and results will be presented with focus on deviations from the expected behaviour, mitigation measures and on lessons learned.

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

Ailavajhala, Mahesh S.; Mitkova, Maria; Gonzalez-Velo, Yago

We explore the radiation induced effects in thin films from the Ge-Se to Ge-Te systems accompanied with silver radiation induced diffusion within these films, emphasizing two distinctive compositional representatives from both systems containing a high concentration of chalcogen or high concentration of Ge. The studies are conducted on blanket chalcogenide films or on device structures containing also a silver source. Data about the electrical conductivity as a function of the radiation dose were collected and discussed based on material characterization analysis. Raman Spectroscopy, X-ray Diffraction Spectroscopy, and Energy Dispersive X-ray Spectroscopy provided us with data about the structure, structural changesmore » occurring as a result of radiation, molecular formations after Ag diffusion into the chalcogenide films, Ag lateral diffusion as a function of radiation and the level of oxidation of the studied films. Analysis of the electrical testing suggests application possibilities of the studied devices for radiation sensing for various conditions.« less

Electronic system for high power load control. [solar arrays

NASA Technical Reports Server (NTRS)

Miller, E. L. (Inventor)

1980-01-01

Parallel current paths are divided into two groups, with control devices in the current paths of one group each having a current limiting resistor, and the control devices in the other group each having no limiting resistor, so that when the control devices of the second group are turned fully on, a short circuit is achieved by the arrangement of parallel current paths. Separate but coordinated control signals are provided to turn on the control devices of the first group and increase their conduction toward saturation as a function of control input, and when fully on, or shortly before, to turn on the control devices of the second group and increase their conduction toward saturation as a function of the control input as that input continues to increase. Electronic means may be used to generate signals. The system may be used for 1-V characteristic measurements of solar arrays as well as for other load control purposes.

Correlation effects in nanoparticle composites: Percolation, packing and tunneling

NASA Astrophysics Data System (ADS)

Mukherjee, Rupam

Percolation is one of the most fundamental and far-reaching physical phenomena, with major implications in a vast variety of fields. The work described in this thesis aims to understand the role of percolation effects in various, seemingly unrelated phenomena, such as the dielectric permittivity of metal-insulator composites, tunneling percolation, and the relationship between percolation and filling factors. Specifically, we investigated 1) the very large enhancement of the dielectric permittivity of a composite metal -- insulator system, RuO2 - CaCu3Ti4O12 (CCTO) near the percolation threshold. For RuO2/CCTO composites, an increase in the real part of the dielectric permittivity (initially about 10 3-104 at 10 kHz) by approximately an order of magnitude is observed in the vicinity of the percolation threshold. 2) In the same system, apart from a classical percolation transition associated with the appearance of a continuous conductance path through RuO2 nanoparticles, at least two additional tunneling percolation transitions are detected. Such behavior is consistent with the recently emerged picture of a quantum conductivity staircase, which predicts several percolation tunneling thresholds in a system with a hierarchy of local tunneling conductance, due to various degrees of proximity of adjacent conducting particles distributed in an insulating matrix. 3) The filling factors of the composites of nanoparticles with different shapes have been studied as a function of volume fraction. Interestingly, like percolation, filling factors also obey critical power law behavior as a function of size ratio of constituent particles.

Video performance for high security applications.

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

Connell, Jack C.; Norman, Bradley C.

2010-06-01

The complexity of physical protection systems has increased to address modern threats to national security and emerging commercial technologies. A key element of modern physical protection systems is the data presented to the human operator used for rapid determination of the cause of an alarm, whether false (e.g., caused by an animal, debris, etc.) or real (e.g., a human adversary). Alarm assessment, the human validation of a sensor alarm, primarily relies on imaging technologies and video systems. Developing measures of effectiveness (MOE) that drive the design or evaluation of a video system or technology becomes a challenge, given the subjectivitymore » of the application (e.g., alarm assessment). Sandia National Laboratories has conducted empirical analysis using field test data and mathematical models such as binomial distribution and Johnson target transfer functions to develop MOEs for video system technologies. Depending on the technology, the task of the security operator and the distance to the target, the Probability of Assessment (PAs) can be determined as a function of a variety of conditions or assumptions. PAs used as an MOE allows the systems engineer to conduct trade studies, make informed design decisions, or evaluate new higher-risk technologies. This paper outlines general video system design trade-offs, discusses ways video can be used to increase system performance and lists MOEs for video systems used in subjective applications such as alarm assessment.« less

Federal Motor Carrier Safety Administration’s advanced system testing utilizing a data acquisition system on the highways (FAST DASH) safety technology evaluation project #3 : novel convex mirrors.

DOT National Transportation Integrated Search

2016-11-01

An independent evaluation of a set of novel prototype mirrors was conducted to determine whether the mirrors perform as well as traditional production mirrors across the basic functions of field of view (FOV), image distortion, and distance estimatio...

Magnetoacoustic tomography with magnetic induction for high-resolution bioimepedance imaging through vector source reconstruction under the static field of MRI magnet

PubMed Central

Mariappan, Leo; Hu, Gang; He, Bin

2014-01-01

Purpose: Magnetoacoustic tomography with magnetic induction (MAT-MI) is an imaging modality to reconstruct the electrical conductivity of biological tissue based on the acoustic measurements of Lorentz force induced tissue vibration. This study presents the feasibility of the authors' new MAT-MI system and vector source imaging algorithm to perform a complete reconstruction of the conductivity distribution of real biological tissues with ultrasound spatial resolution. Methods: In the present study, using ultrasound beamformation, imaging point spread functions are designed to reconstruct the induced vector source in the object which is used to estimate the object conductivity distribution. Both numerical studies and phantom experiments are performed to demonstrate the merits of the proposed method. Also, through the numerical simulations, the full width half maximum of the imaging point spread function is calculated to estimate of the spatial resolution. The tissue phantom experiments are performed with a MAT-MI imaging system in the static field of a 9.4 T magnetic resonance imaging magnet. Results: The image reconstruction through vector beamformation in the numerical and experimental studies gives a reliable estimate of the conductivity distribution in the object with a ∼1.5 mm spatial resolution corresponding to the imaging system frequency of 500 kHz ultrasound. In addition, the experiment results suggest that MAT-MI under high static magnetic field environment is able to reconstruct images of tissue-mimicking gel phantoms and real tissue samples with reliable conductivity contrast. Conclusions: The results demonstrate that MAT-MI is able to image the electrical conductivity properties of biological tissues with better than 2 mm spatial resolution at 500 kHz, and the imaging with MAT-MI under a high static magnetic field environment is able to provide improved imaging contrast for biological tissue conductivity reconstruction. PMID:24506649

Capturing patients' needs in casemix: a systematic literature review on the value of adding functioning information in reimbursement systems.

PubMed

Hopfe, Maren; Stucki, Gerold; Marshall, Ric; Twomey, Conal D; Üstün, T Bedirhan; Prodinger, Birgit

2016-02-03

Contemporary casemix systems for health services need to ensure that payment rates adequately account for actual resource consumption based on patients' needs for services. It has been argued that functioning information, as one important determinant of health service provision and resource use, should be taken into account when developing casemix systems. However, there has to date been little systematic collation of the evidence on the extent to which the addition of functioning information into existing casemix systems adds value to those systems with regard to the predictive power and resource variation explained by the groupings of these systems. Thus, the objective of this research was to examine the value of adding functioning information into casemix systems with respect to the prediction of resource use as measured by costs and length of stay. A systematic literature review was performed. Peer-reviewed studies, published before May 2014 were retrieved from CINAHL, EconLit, Embase, JSTOR, PubMed and Sociological Abstracts using keywords related to functioning ('Functioning', 'Functional status', 'Function*, 'ICF', 'International Classification of Functioning, Disability and Health', 'Activities of Daily Living' or 'ADL') and casemix systems ('Casemix', 'case mix', 'Diagnosis Related Groups', 'Function Related Groups', 'Resource Utilization Groups' or 'AN-SNAP'). In addition, a hand search of reference lists of included articles was conducted. Information about study aims, design, country, setting, methods, outcome variables, study results, and information regarding the authors' discussion of results, study limitations and implications was extracted. Ten included studies provided evidence demonstrating that adding functioning information into casemix systems improves predictive ability and fosters homogeneity in casemix groups with regard to costs and length of stay. Collection and integration of functioning information varied across studies. Results suggest that, in particular, DRG casemix systems can be improved in predicting resource use and capturing outcomes for frail elderly or severely functioning-impaired patients. Further exploration of the value of adding functioning information into casemix systems is one promising approach to improve casemix systems ability to adequately capture the differences in patient's needs for services and to better predict resource use.

Fun cube based brain gym cognitive function assessment system.

PubMed

Zhang, Tao; Lin, Chung-Chih; Yu, Tsang-Chu; Sun, Jing; Hsu, Wen-Chuin; Wong, Alice May-Kuen

2017-05-01

The aim of this study is to design and develop a fun cube (FC) based brain gym (BG) cognitive function assessment system using the wireless sensor network and multimedia technologies. The system comprised (1) interaction devices, FCs and a workstation used as interactive tools for collecting and transferring data to the server, (2) a BG information management system responsible for managing the cognitive games and storing test results, and (3) a feedback system used for conducting the analysis of cognitive functions to assist caregivers in screening high risk groups with mild cognitive impairment. Three kinds of experiments were performed to evaluate the developed FC-based BG cognitive function assessment system. The experimental results showed that the Pearson correlation coefficient between the system's evaluation outcomes and the traditional Montreal Cognitive Assessment scores was 0.83. The average Technology Acceptance Model 2 score was close to six for 31 elderly subjects. Most subjects considered that the brain games are interesting and the FC human-machine interface is easy to learn and operate. The control group and the cognitive impairment group had statistically significant difference with respect to the accuracy of and the time taken for the brain cognitive function assessment games, including Animal Naming, Color Search, Trail Making Test, Change Blindness, and Forward / Backward Digit Span. Copyright © 2017 Elsevier Ltd. All rights reserved.

Design and fabrication of integrated micro/macrostructure for 3D functional gradient systems based on additive manufacturing

NASA Astrophysics Data System (ADS)

Yin, Ming; Xie, Luofeng; Jiang, Weifeng; Yin, Guofu

2018-05-01

Functional gradient systems have important applications in many areas. Although a 2D dielectric structure that serves as the gradient index medium for controlling electromagnetic waves is well established, it may not be suitable for application in 3D case. In this paper, we present a method to realize functional gradient systems with 3D integrated micro/macrostructure. The homogenization of the structure is studied in detail by conducting band diagram analysis. The analysis shows that the effective medium approximation is valid even when periodicity is comparable to wavelength. The condition to ensure the polarization-invariant, isotropic, and frequency-independent property is investigated. The scheme for the design and fabrication of 3D systems requiring spatial material property distribution is presented. By using the vat photopolymerization process, a large overall size of macrostructure at the system level and precise fine features of microstructure at the unit cell level are realized, thus demonstrating considerable scalability of the system for wave manipulation.

Robust approximation-free prescribed performance control for nonlinear systems and its application

NASA Astrophysics Data System (ADS)

Sun, Ruisheng; Na, Jing; Zhu, Bin

2018-02-01

This paper presents a robust prescribed performance control approach and its application to nonlinear tail-controlled missile systems with unknown dynamics and uncertainties. The idea of prescribed performance function (PPF) is incorporated into the control design, such that both the steady-state and transient control performance can be strictly guaranteed. Unlike conventional PPF-based control methods, we further tailor a recently proposed systematic control design procedure (i.e. approximation-free control) using the transformed tracking error dynamics, which provides a proportional-like control action. Hence, the function approximators (e.g. neural networks, fuzzy systems) that are widely used to address the unknown nonlinearities in the nonlinear control designs are not needed. The proposed control design leads to a robust yet simplified function approximation-free control for nonlinear systems. The closed-loop system stability and the control error convergence are all rigorously proved. Finally, comparative simulations are conducted based on nonlinear missile systems to validate the improved response and the robustness of the proposed control method.

Miniature Loop Heat Pipe with Multiple Evaporators for Thermal Control of Small Spacecraft

NASA Technical Reports Server (NTRS)

Ku, Jentung; Ottenstein, Laura; Douglas, Denya; Pauken, Michael; Birur, Gajanana

2005-01-01

This paper presents an advanced miniature heat transport system for thermal control of small spacecraft. The thermal system consists of a loop heat pipe (LHP) with multiple evaporators and multiple deployable radiators for heat transfer, and variable emittance coatings on the radiators for performance enhancement. Thermoelectric coolers are used to control the loop operating temperature. The thermal system combines the functions of variable conductance heat pipes, thermal switches, thermal diodes, and the state-of-the-art LHPs into a single integrated thermal system. It retains all the performance characteristics of state-of-the-art LHPs and offers additional advantages to enhance the functionality, performance, versatility, and reliability of the system. Steady state and transient analytical models have been developed, and scaling criteria have also been established. A breadboard unit has been built for functional testing in laboratory and thermal vacuum environments. Experimental results show excellent performance of the thermal system and correlate very well with theoretical predictions.

A semi-symmetric image encryption scheme based on the function projective synchronization of two hyperchaotic systems

PubMed Central

Li, Jinqing; Qi, Hui; Cong, Ligang; Yang, Huamin

2017-01-01

Both symmetric and asymmetric color image encryption have advantages and disadvantages. In order to combine their advantages and try to overcome their disadvantages, chaos synchronization is used to avoid the key transmission for the proposed semi-symmetric image encryption scheme. Our scheme is a hybrid chaotic encryption algorithm, and it consists of a scrambling stage and a diffusion stage. The control law and the update rule of function projective synchronization between the 3-cell quantum cellular neural networks (QCNN) response system and the 6th-order cellular neural network (CNN) drive system are formulated. Since the function projective synchronization is used to synchronize the response system and drive system, Alice and Bob got the key by two different chaotic systems independently and avoid the key transmission by some extra security links, which prevents security key leakage during the transmission. Both numerical simulations and security analyses such as information entropy analysis, differential attack are conducted to verify the feasibility, security, and efficiency of the proposed scheme. PMID:28910349

Gamma Rhythm Simulations in Alzheimer's Disease

NASA Astrophysics Data System (ADS)

Montgomery, Samuel; Perez, Carlos; Ullah, Ghanim

The different neural rhythms that occur during the sleep-wake cycle regulate the brain's multiple functions. Memory acquisition occurs during fast gamma rhythms during consciousness, while slow oscillations mediate memory consolidation and erasure during sleep. At the neural network level, these rhythms are generated by the finely timed activity within excitatory and inhibitory neurons. In Alzheimer's Disease (AD) the function of inhibitory neurons is compromised due to an increase in amyloid beta (A β) leading to elevated sodium leakage from extracellular space in the hippocampus. Using a Hodgkin-Huxley formalism, heightened sodium leakage current into inhibitory neurons is observed to compromise functionality. Using a simple two neuron system it was observed that as the conductance of the sodium leakage current is increased in inhibitory neurons there is a significant decrease in spiking frequency regarding the membrane potential. This triggers a significant increase in excitatory spiking leading to aberrant network behavior similar to that seen in AD patients. The next step is to extend this model to a larger neuronal system with varying synaptic densities and conductance strengths as well as deterministic and stochastic drives.

Thermoregulation in multiple sclerosis.

PubMed

Davis, Scott L; Wilson, Thad E; White, Andrea T; Frohman, Elliot M

2010-11-01

Multiple sclerosis (MS) is a progressive neurological disorder that disrupts axonal myelin in the central nervous system. Demyelination produces alterations in saltatory conduction, slowed conduction velocity, and a predisposition to conduction block. An estimated 60-80% of MS patients experience temporary worsening of clinical signs and neurological symptoms with heat exposure. Additionally, MS may produce impaired neural control of autonomic and endocrine functions. This review focuses on five main themes regarding the current understanding of thermoregulatory dysfunction in MS: 1) heat sensitivity; 2) central regulation of body temperature; 3) thermoregulatory effector responses; 4) heat-induced fatigue; and 5) countermeasures to improve or maintain function during thermal stress. Heat sensitivity in MS is related to the detrimental effects of increased temperature on action potential propagation in demyelinated axons, resulting in conduction slowing and/or block, which can be quantitatively characterized using precise measurements of ocular movements. MS lesions can also occur in areas of the brain responsible for the control and regulation of body temperature and thermoregulatory effector responses, resulting in impaired neural control of sudomotor pathways or neural-induced changes in eccrine sweat glands, as evidenced by observations of reduced sweating responses in MS patients. Fatigue during thermal stress is common in MS and results in decreased motor function and increased symptomatology likely due to impairments in central conduction. Although not comprehensive, some evidence exists concerning treatments (cooling, precooling, and pharmacological) for the MS patient to preserve function and decrease symptom worsening during heat stress.

Use and Adoption of an Assisted Cognition System to Support Therapies for People with Dementia.

PubMed

Navarro, René F; Rodríguez, Marcela D; Favela, Jesús

2016-01-01

The cognitive deficits in persons with dementia (PwD) can produce significant functional impairment from early stages. Although memory decline is most prominent, impairments in attention, orientation, language, reasoning, and executive functioning are also common. Dementia is also characterized by changes in personality and behavioral functioning that can be very challenging for caregivers and patients. This paper presents results on the use and adoption of an assisted cognition system to support occupational therapy to address psychological and behavioral symptoms of dementia. During 16 weeks, we conducted an in situ evaluation with two caregiver-PwD dyads to assess the adoption and effectiveness of the system to ameliorate challenging behaviors and reducing caregiver burden. Evaluation results indicate that intervention personalization and a touch-based interface encouraged the adoption of the system, helping reduce challenging behaviors in PwD and caregiver burden.

The performance of a piezoelectric-sensor-based SHM system under a combined cryogenic temperature and vibration environment

NASA Astrophysics Data System (ADS)

Qing, Xinlin P.; Beard, Shawn J.; Kumar, Amrita; Sullivan, Kevin; Aguilar, Robert; Merchant, Munir; Taniguchi, Mike

2008-10-01

A series of tests have been conducted to determine the survivability and functionality of a piezoelectric-sensor-based active structural health monitoring (SHM) SMART Tape system under the operating conditions of typical liquid rocket engines such as cryogenic temperature and vibration loads. The performance of different piezoelectric sensors and a low temperature adhesive under cryogenic temperature was first investigated. The active SHM system for liquid rocket engines was exposed to flight vibration and shock environments on a simulated large booster LOX-H2 engine propellant duct conditioned to cryogenic temperatures to evaluate the physical robustness of the built-in sensor network as well as operational survivability and functionality. Test results demonstrated that the developed SMART Tape system can withstand operational levels of vibration and shock energy on a representative rocket engine duct assembly, and is functional under the combined cryogenic temperature and vibration environment.

Thermal Conductivity and Thermal Gradient Cyclic Behavior of Refractory Silicate Coatings on SiC/SiC Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Lee, Kang N.; Miller, Robert A.

2001-01-01

Plasma-sprayed mullite and BSAS coatings have been developed to protect SiC/SiC ceramic matrix composites from high temperature environmental attack. In this study, thermal conductivity and thermal barrier functions of these coating systems are evaluated using a laser high-heat-flux test rig. The effects of water vapor on coating thermal conductivity and durability are studied by using alternating furnace and laser thermal gradient cyclic tests. The influence of laser high thermal-gradient cycling on coating failure modes is also investigated.

Attentional and physiological processing of food images in functional dyspepsia patients: A pilot study.

PubMed

Lee, In-Seon; Preissl, Hubert; Giel, Katrin; Schag, Kathrin; Enck, Paul

2018-01-23

The food-related behavior of functional dyspepsia has been attracting more interest of late. This pilot study aims to provide evidence of the physiological, emotional, and attentional aspects of food processing in functional dyspepsia patients. The study was performed in 15 functional dyspepsia patients and 17 healthy controls after a standard breakfast. We measured autonomic nervous system activity using skin conductance response and heart rate variability, emotional response using facial electromyography, and visual attention using eyetracking during the visual stimuli of food/non-food images. In comparison to healthy controls, functional dyspepsia patients showed a greater craving for food, a decreased intake of food, more dyspeptic symptoms, lower pleasantness rating of food images (particularly of high fat), decreased low frequency/high frequency ratio of heart rate variability, and suppressed total processing time of food images. There were no significant differences of skin conductance response and facial electromyography data between groups. The results suggest that high level cognitive functions rather than autonomic and emotional mechanisms are more liable to function differently in functional dyspepsia patients. Abnormal dietary behavior, reduced subjective rating of pleasantness and visual attention to food should be considered as important pathophysiological characteristics in functional dyspepsia.

Theater Army Medical Management Information System: A MANPRINT evaluation

DTIC Science & Technology

1989-06-01

Management Information System (TAMMIS) and the division level version of the system, TAMMIS-D. TAMMIS/ TAMMIS-D are automated, on-line, interactive, microcomputer systems designed to manage combat medical information but capable of performing peacetime functions as well. The systems were developed to meet the needs of medical commanders by providing timely, accurate, and relevant information on the status of patients, medical units, and medical supplies on the battlefield. The IOT&E was conducted at Fort Lewis, WA in tents erected between two-story barracks

Molecular regulation of urea cycle function by the liver glucocorticoid receptor.

PubMed

Okun, Jürgen G; Conway, Sean; Schmidt, Kathrin V; Schumacher, Jonas; Wang, Xiaoyue; de Guia, Roldan; Zota, Annika; Klement, Johanna; Seibert, Oksana; Peters, Achim; Maida, Adriano; Herzig, Stephan; Rose, Adam J

2015-10-01

One of the major side effects of glucocorticoid (GC) treatment is lean tissue wasting, indicating a prominent role in systemic amino acid metabolism. In order to uncover a novel aspect of GCs and their intracellular-receptor, the glucocorticoid receptor (GR), on metabolic control, we conducted amino acid and acylcarnitine profiling in human and mouse models of GC/GR gain- and loss-of-function. Blood serum and tissue metabolite levels were determined in Human Addison's disease (AD) patients as well as in mouse models of systemic and liver-specific GR loss-of-function (AAV-miR-GR) with or without dexamethasone (DEX) treatments. Body composition and neuromuscular and metabolic function tests were conducted in vivo and ex vivo, the latter using precision cut liver slices. A serum metabolite signature of impaired urea cycle function (i.e. higher [ARG]:[ORN + CIT]) was observed in human (CTRL: 0.45 ± 0.03, AD: 1.29 ± 0.04; p < 0.001) and mouse (AAV-miR-NC: 0.97 ± 0.13, AAV-miR-GR: 2.20 ± 0.19; p < 0.001) GC/GR loss-of-function, with similar patterns also observed in liver. Serum urea levels were consistently affected by GC/GR gain- (∼+32%) and loss (∼-30%) -of-function. Combined liver-specific GR loss-of-function with DEX treatment revealed a tissue-autonomous role for the GR to coordinate an upregulation of liver urea production rate in vivo and ex vivo, and prevent hyperammonaemia and associated neuromuscular dysfunction in vivo. Liver mRNA expression profiling and GR-cistrome mining identified Arginase I (ARG1) a urea cycle gene targeted by the liver GR. The liver GR controls systemic and liver urea cycle function by transcriptional regulation of ARG1 expression.

NASA Glenn 1-by 1-Foot Supersonic Wind Tunnel User Manual

NASA Technical Reports Server (NTRS)

Seablom, Kirk D.; Soeder, Ronald H.; Stark, David E.; Leone, John F. X.; Henry, Michael W.

1999-01-01

This manual describes the NASA Glenn Research Center's 1 - by 1 -Foot Supersonic Wind Tunnel and provides information for customers who wish to conduct experiments in this facility. Tunnel performance envelopes of total pressure, total temperature, and dynamic pressure as a function of test section Mach number are presented. For each Mach number, maps are presented of Reynolds number per foot as a function of the total air temperature at the test section inlet for constant total air pressure at the inlet. General support systems-such as the service air, combustion air, altitude exhaust system, auxiliary bleed system, model hydraulic system, schlieren system, model pressure-sensitive paint, and laser sheet system are discussed. In addition, instrumentation and data processing, acquisition systems are described, pretest meeting formats and schedules are outlined, and customer responsibilities and personnel safety are addressed.

Design Effects and Generalized Variance Functions for the 1990-91 Schools and Staffing Survey (SASS). Volume II. Technical Report.

ERIC Educational Resources Information Center

Salvucci, Sameena; And Others

This technical report provides the results of a study on the calculation and use of generalized variance functions (GVFs) and design effects for the 1990-91 Schools and Staffing Survey (SASS). The SASS is a periodic integrated system of sample surveys conducted by the National Center for Education Statistics (NCES) that produces sampling variances…

The Use of Functional Behavioural Assessment for Students with Challenging Behaviours: Current Patterns and Experience of Australian Practitioners.

ERIC Educational Resources Information Center

O'Neill, Sue; Stephenson, Jennifer

2010-01-01

With the growing adoption of the Positive Behaviour Support (PBS) system state-wide in New South Wales, Australia, it was of interest to determine the readiness of behaviour specialists to conduct Functional Behaviour Assessments (FBA) as part of the third tier of School-wide PBS provision. This article presents the findings from a survey…

Invited review: gravitational biology of the neuromotor systems: a perspective to the next era

NASA Technical Reports Server (NTRS)

Edgerton, V. R.; Roy, R. R.

2000-01-01

Earth's gravity has had a significant impact on the designs of the neuromotor systems that have evolved. Early indications are that gravity also plays a key role in the ontogenesis of some of these design features. The purpose of the present review is not to assess and interpret a body of knowledge in the usual sense of a review but to look ahead, given some of the general concepts that have evolved and observations made to date, which can guide our future approach to gravitational biology. We are now approaching an era in gravitational biology during which well-controlled experiments can be conducted for sustained periods in a microgravity environment. Thus it is now possible to study in greater detail the role of gravity in phylogenesis and ontogenesis. Experiments can range from those conducted on the simplest levels of organization of the components that comprise the neuromotor system to those conducted on the whole organism. Generally, the impact of Earth's gravitational environment on living systems becomes more complex as the level of integration of the biological phenomenon of interest increases. Studies of the effects of gravitational vectors on neuromotor systems have and should continue to provide unique insight into these mechanisms that control and maintain neural control systems designed to function in Earth's gravitational environment. A number of examples are given of how a gravitational biology perspective can lead to a clearer understanding of neuromotor disorders. Furthermore, the technologies developed for spaceflight studies have contributed and should continue to contribute to studies of motor dysfunctions, such as spinal cord injury and stroke. Disorders associated with energy support and delivery systems and how these functions are altered by sedentary life styles at 1 G and by space travel in a microgravity environment are also discussed.

A safety vs efficiency trade-off identified in the hydraulic pathway of grass leaves is decoupled from photosynthesis, stomatal conductance and precipitation.

PubMed

Ocheltree, Troy W; Nippert, Jesse B; Prasad, P V Vara

2016-04-01

A common theme in plant physiological research is the trade-off between stress tolerance and growth; an example of this trade-off at the tissue level is the safety vs efficiency hypothesis, which suggests that plants with the greatest resistance to hydraulic failure should have low maximum hydraulic conductance. Here, we quantified the leaf-level drought tolerance of nine C4 grasses as the leaf water potential at which plants lost 50% (P50 × RR ) of maximum leaf hydraulic conductance (Ksat ), and compared this trait with other leaf-level and whole-plant functions. We found a clear trade-off between Ksat and P50 × RR when Ksat was normalized by leaf area and mass (P = 0.05 and 0.01, respectively). However, no trade-off existed between P50 × RR and gas-exchange rates; rather, there was a positive relationship between P50 × RR and photosynthesis (P = 0.08). P50 × RR was not correlated with species distributions based on precipitation (P = 0.70), but was correlated with temperature during the wettest quarter of the year (P < 0.01). These results suggest a trade-off between safety and efficiency in the hydraulic system of grass leaves, which can be decoupled from other leaf-level functions. The unique physiology of C4 plants and adaptations to pulse-driven systems may provide mechanisms that could decouple hydraulic conductance from other plant functions. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

New ways of looking at sector demand and sector alerts

DOT National Transportation Integrated Search

2011-03-31

This report presents the latest results of research conducted at the Volpe Center on improving air traffic demand predictions and enhancing the Traffic Flow Management System (TFMS) Monitor/Alert function for identifying potential congestion at Natio...

45 CFR 307.10 - Functional requirements for computerized support enforcement systems in operation by October 1...

Code of Federal Regulations, 2011 CFR

2011-10-01

... information such as social security numbers, names, dates of birth, home addresses and mailing addresses... enable the Office to monitor State operations and assess program performance through the audit conducted...

Investigation into the Use of Texturing for Real-Time Computer Animation.

DTIC Science & Technology

1987-12-01

produce a rough polygon surface [7]. Research in the area of real time texturing has also been conducted. Using a specially designed multi-processor system ...Oka, Tsutsui, Ohba, Kurauchi and Tago have introduced real-time manipulation of texture mapped surfaces [8]. Using multi- processors, systems will...a call to the system function defpattern(n,size,mask) short n,size; short *mask, which takes as input an index to a system table of patterns, a

Estimation on the self recovery behavior of low-conductivity layer in landfill final cover by laboratory conductivity tests.

PubMed

Kwon, O; Park, J

2006-11-01

This study examined the application of a Self Recovering Sustainable Layer (SRSL) as a landfill final cover. Low-conductivity layers in landfill covers are known to have problems associated with cracking as a result of the differential settlement or climatic changes. A SRSL is defined as a layer with chemical properties that reduces the increased hydraulic conductivity resulting from cracking by forming low-conductivity precipitates of chemicals contained in the layer. In this study, the formation of precipitates was confirmed using a batch test, spectroscopic analysis and mineralogical speciation tests. The possibility of secondary contamination due to the chemicals used for recovery was evaluated using a leaching test. A laboratory conductivity test was performed on a single layer composed of each chemical as well as on a 2-layer system. The recovery performance of the SRSL was estimated by developing artificial cracks in the specimens and observing the change in hydraulic conductivity as a function of time. In the laboratory conductivity test, the hydraulic conductivity of a 2-layer system as well as those of the individual layers that comprise the 2-layer system was estimated. In addition sodium ash was found to enhance the reduction in conductivity. A significant increase in conductivity was observed after the cracks developed but this was reduced with time, which indicated that the SRSL has a proper recovering performance. In conclusion, a SRSL can be used as a landfill final cover that could maintain low-conductivity even after the serious damages due to settlement.

Using Local Perturbations To Manipulate and Control Pointer States in Quantum Dot Systems

NASA Astrophysics Data System (ADS)

Akis, Richard; Speyer, Gil; Ferry, David; Brunner, Roland

2012-02-01

Recently, scanning gate microscopy (SGM) was used to image scarred wave functions in an open InAs quantum dot[1]. The SGM tip provides a local potential perturbation and imaging is performed by measuring changes in conductance. Scarred wave functions, long associated with quantum chaos, have been shown in open dots to correspond to pointer states[2], eigenstates that survive the decoherence process that occurs via coupling to the environment. Pointer states modulate the conductance, yielding periodic fluctuations and the scars, normally thought unstable, are stabilized by quantum Darwinism [3]. We shall show that, beyond probing, pointer states can be manipulated by local perturbations. Particularly interesting effects occur in coupled quantum dot arrays, where a pointer state localized in one dot can be shifted over into another with a perturbation in a completely different part of the system. These nonlocal effects may perhaps be exploited to give such systems an exotic functionality. [1] A. M. Burke, R. Akis, T. E. Day, Gil Speyer, D. K. Ferry, and B. R. Bennett, Phys. Rev. Lett. 104, 176801 (2010). [2] D. K. Ferry, R. Akis, and J. P. Bird, Phys. Rev. Lett. 104, 176801 (2004). [3] R. Brunner, R. Akis,D. K. Ferry, F. Kuchar,and R. Meisels, Phys. Rev. Lett. 101, 024102 (2008).

Enunciative categories in the description of language functioning of mothers and infants aged 1-4 months.

PubMed

Kruel, Cristina Saling; Rechia, Inaê Costa; Oliveira, Luciéle Dias; Souza, Ana Paula Ramos de

2016-01-01

To present categories which explain the language functioning between infants and their mothers from Benveniste's concept of semiotic system, and verify whether such categories can be described numerically. Four mother-infant dyads were monitored in three stages. The first study consisted of a qualitative analysis of the transcribed video recordings conducted in each stage. We intended to identify the enunciative principles associated with the relationship between the semiotic system of the infant's body and their mother's language, namely, the principles of interpretancy and homology. The other study was conducted by means of a descriptive numerical analysis of the enunciative categories and the infant caregiver scale of behavior, using the ELAN software (EUDICO Linguistic Anotador). Mutuality in mother-infant interactions was observed in most of the scenes analyzed. Productive enunciative categories demonstrated in the infant's demand/mother's interpretation relation was identified in homology and interpretancy. It was also possible to use these categories to describe the mother-infant interactions numerically. In addition, other categories emerged because there are other subtypes of maternal productions not directly related to infant demand. This shows that infants are exposed to language of heterogeneous characteristics. The concept of semiotic system allowed the proposition of language functioning categories identifiable in the mother-infant relationship. Such categories were described numerically.

Effect of Probiotics on Central Nervous System Functions in Animals and Humans: A Systematic Review

PubMed Central

Wang, Huiying; Lee, In-Seon; Braun, Christoph; Enck, Paul

2016-01-01

To systematically review the effects of probiotics on central nervous system function in animals and humans, to summarize effective interventions (species of probiotic, dose, duration), and to analyze the possibility of translating preclinical studies. Literature searches were conducted in Pubmed, Medline, Embase, and the Cochrane Library. Only randomized controlled trials were included. In total, 38 studies were included: 25 in animals and 15 in humans (2 studies were conducted in both). Most studies used Bifidobacterium (eg, B. longum, B. breve, and B. infantis) and Lactobacillus (eg, L. helveticus, and L. rhamnosus), with doses between 109 and 1010 colony-forming units for 2 weeks in animals and 4 weeks in humans. These probiotics showed efficacy in improving psychiatric disorder-related behaviors including anxiety, depression, autism spectrum disorder (ASD), obsessive-compulsive disorder, and memory abilities, including spatial and non-spatial memory. Because many of the basic science studies showed some efficacy of probiotics on central nervous system function, this background may guide and promote further preclinical and clinical studies. Translating animal studies to human studies has obvious limitations but also suggests possibilities. Here, we provide several suggestions for the translation of animal studies. More experimental designs with both behavioral and neuroimaging measures in healthy volunteers and patients are needed in the future. PMID:27413138

Effect of Probiotics on Central Nervous System Functions in Animals and Humans: A Systematic Review.

PubMed

Wang, Huiying; Lee, In-Seon; Braun, Christoph; Enck, Paul

2016-10-30

To systematically review the effects of probiotics on central nervous system function in animals and humans, to summarize effective interventions (species of probiotic, dose, duration), and to analyze the possibility of translating preclinical studies. Literature searches were conducted in Pubmed, Medline, Embase, and the Cochrane Library. Only randomized controlled trials were included. In total, 38 studies were included: 25 in animals and 15 in humans (2 studies were conducted in both). Most studies used Bifidobacterium (eg, B. longum , B. breve , and B. infantis ) and Lactobacillus (eg, L. helveticus , and L. rhamnosus ), with doses between 10⁸ and 10¹⁰ colony-forming units for 2 weeks in animals and 4 weeks in humans. These probiotics showed efficacy in improving psychiatric disorder-related behaviors including anxiety, depression, autism spectrum disorder (ASD), obsessive-compulsive disorder, and memory abilities, including spatial and non-spatial memory. Because many of the basic science studies showed some efficacy of probiotics on central nervous system function, this background may guide and promote further preclinical and clinical studies. Translating animal studies to human studies has obvious limitations but also suggests possibilities. Here, we provide several suggestions for the translation of animal studies. More experimental designs with both behavioral and neuroimaging measures in healthy volunteers and patients are needed in the future.

Theoretical study of the dependence of single impurity Anderson model on various parameters within distributional exact diagonalization method

NASA Astrophysics Data System (ADS)

Syaina, L. P.; Majidi, M. A.

2018-04-01

Single impurity Anderson model describes a system consisting of non-interacting conduction electrons coupled with a localized orbital having strongly interacting electrons at a particular site. This model has been proven successful to explain the phenomenon of metal-insulator transition through Anderson localization. Despite the well-understood behaviors of the model, little has been explored theoretically on how the model properties gradually evolve as functions of hybridization parameter, interaction energy, impurity concentration, and temperature. Here, we propose to do a theoretical study on those aspects of a single impurity Anderson model using the distributional exact diagonalization method. We solve the model Hamiltonian by randomly generating sampling distribution of some conducting electron energy levels with various number of occupying electrons. The resulting eigenvalues and eigenstates are then used to define the local single-particle Green function for each sampled electron energy distribution using Lehmann representation. Later, we extract the corresponding self-energy of each distribution, then average over all the distributions and construct the local Green function of the system to calculate the density of states. We repeat this procedure for various values of those controllable parameters, and discuss our results in connection with the criteria of the occurrence of metal-insulator transition in this system.

Soil Temperature and Moisture Profile (STAMP) System Handbook

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

Cook, David R.

The soil temperature and moisture profile system (STAMP) provides vertical profiles of soil temperature, soil water content (soil-type specific and loam type), plant water availability, soil conductivity, and real dielectric permittivity as a function of depth below the ground surface at half-hourly intervals, and precipitation at one-minute intervals. The profiles are measured directly by in situ probes at all extended facilities of the SGP climate research site. The profiles are derived from measurements of soil energy conductivity. Atmospheric scientists use the data in climate models to determine boundary conditions and to estimate the surface energy flux. The data are alsomore » useful to hydrologists, soil scientists, and agricultural scientists for determining the state of the soil. The STAMP system replaced the SWATS system in early 2016.« less

Bioculture System Validation

NASA Technical Reports Server (NTRS)

Sato, Kevin Y.

2012-01-01

The Bioculture System first flight will be to validate the performance of the hardware and its automated and manual operational capabilities in the space flight environment of the International Space Station. Biology, Engineering, and Operations tests will be conducted in the Bioculture System fully characterize its automated and manual functions to support cell culturing for short and long durations. No hypothesis-driven research will be conducted with biological sample, and the science leads have all provided their concurrence that none of the data they collect will be considered as proprietary and can be free distributed to the science community. The outcome of the validation flight will be to commission the hardware for use by the science community. This presentation will provide non-proprietary details about the Bioculture System and information about the activities for the first flight.

A model study of tunneling conductance spectra of ferromagnetically ordered manganites

NASA Astrophysics Data System (ADS)

Panda, Saswati; Kar, J. K.; Rout, G. C.

2018-02-01

We report here the interplay of ferromagnetism (FM) and charge density wave (CDW) in manganese oxide systems through the study of tunneling conductance spectra. The model Hamiltonian consists of strong Heisenberg coupling in core t2g band electrons within mean-field approximation giving rise to ferromagnetism. Ferromagnetism is induced in the itinerant eg electrons due to Kubo-Ohata type double exchange (DE) interaction among the t2g and eg electrons. The charge ordering (CO) present in the eg band giving rise to CDW interaction is considered as the extra-mechanism to explain the colossal magnetoresistance (CMR) property of manganites. The magnetic and CDW order parameters are calculated using Zubarev's Green's function technique and solved self-consistently and numerically. The eg electron density of states (DOS) calculated from the imaginary part of the Green's function explains the experimentally observed tunneling conductance spectra. The DOS graph exhibits a parabolic gap near the Fermi energy as observed in tunneling conductance spectra experiments.

Vegetation-zonation patterns across a temperate mountain cloud forest ecotone are not explained by variation in hydraulic functioning or water relations.

PubMed

Berry, Z Carter; Johnson, Daniel M; Reinhardt, Keith

2015-09-01

Many studies have demonstrated linkages between the occurrence of fog and ecophysiological functioning in cloud forests, but few have investigated hydraulic functioning as a determining factor that explains sharp changes in vegetation. The objective of this study was to compare the plant water status during cloud-immersed and non-immersed conditions and hydraulic vulnerability in branches and roots of species across a temperate, mountain fog ecotone. Because cloud forests are often dark, cool and very moist, we expected cloud forest species to have less drought-tolerant characteristics (i.e., lower Pe and P50-the pressures required to induce a 12 and 50% loss in hydraulic conductivity, respectively) relative to non-cloud forest species in adjacent (lower elevation) forests. Additionally, due to the ability of cloud forest species to absorb cloud-fog water, we predicted greater improvements in hydraulic functioning during fog in cloud forest species relative to non-cloud forest species. Across the cloud forest ecotone, most species measured were very resistant to losses in conductivity with branch P50 values from -4.5 to -6.0 MPa, hydraulic safety margins (Ψmin - P50) >1.5 MPa and low calculated hydraulic conductivity losses. Roots had greater vulnerabilities, with P50 values ranging from -1.4 to -2.5 MPa, leading to greater predicted losses in conductivity (∼20%). Calculated values suggested strong losses of midday leaf hydraulic conductance in three of the four species, supporting the hydraulic segmentation hypothesis. In both cloud forest and hardwood species, Ψs were greater on foggy days than sunny days, demonstrating the importance of fog periods to plant water balance across fog regimes. Thus, frequent fog did not result in systemic changes in hydraulic functioning or vulnerability to embolism across our temperate cloud forest ecotone. Finally, roots functioned with lower hydraulic conductivity than branches, suggesting that they may serve as more sensitive indicators of hydraulic functioning in these mesic, foggy ecosystems. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Conductive properties of switchable photoluminescence thermosetting systems based on liquid crystals.

PubMed

Tercjak, Agnieszka; Gutierrez, Junkal; Ocando, Connie; Mondragon, Iñaki

2010-03-16

Conductive properties of different thermosetting materials modified with nematic 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) liquid crystal and rutile TiO(2) nanoparticles were successfully studied by means of tunneling atomic force miscroscopy (TUNA). Taking into account the liquid crystal state of the HBC at room temperature, depending on both the HBC content and the presence of TiO(2) nanoparticles, designed materials showed different TUNA currents passed through the sample. The addition of TiO(2) nanoparticles into the systems multiply the detected current if compared to the thermosetting systems without TiO(2) nanoparticles and simultaneously stabilized the current passed through the sample, making the process reversible since the absolute current values were almost the same applying both negative and positive voltage. Moreover, thermosetting systems modified with liquid crystals with and without TiO(2) nanoparticles are photoluminescence switchable materials as a function of temperature gradient during repeatable heating/cooling cycle. Conductive properties of switchable photoluminescence thermosetting systems based on liquid crystals can allow them to find potential application in the field of photoresponsive devices, with a high contrast ratio between transparent and opaque states.

Comparison between moving and stationary transmitter systems in induction logging

NASA Astrophysics Data System (ADS)

Poddar, M.; Caleb Dhanasekaran, P.; Prabhakar Rao, K.

1985-09-01

In a general treatment of the theory of induction logging, an exact integral representation has been obtained for the mutual impedance between a vertical dipole transmitter and a coaxial dipole receiver in a three layered earth. Based on this representation, a computer model has been devised using the traditional Slingram system of induction logging and the comparatively new Turam system, ignoring borehole effects. The model results indicate that due to its much larger response, the Turam system is in general preferable to the Slingram in mineral and groundwater investigations where formation conductivity much less than 1 S/m is generally encountered. However, if the surrounding media are conductive (more than 0.1 S/m), the Turam system suffers from large amplitude attenuation and phase rotation of the primary field caused by the conductive surrounding, and is less useful than the Slingram system which does not so suffer, unless the target bed is shallow. Because it is a more complex function of system parameters than the corresponding Slingram log, a Turam log can be conveniently interpreted only by the modern inverse method using a fast algorithm for the forward solution and a high speed digital computer.

Heat dissipation for microprocessor using multiwalled carbon nanotubes based liquid.

PubMed

Hung Thang, Bui; Trinh, Pham Van; Chuc, Nguyen Van; Khoi, Phan Hong; Minh, Phan Ngoc

2013-01-01

Carbon nanotubes (CNTs) are one of the most valuable materials with high thermal conductivity (2000 W/m · K compared with thermal conductivity of Ag 419 W/m · K). This suggested an approach in applying the CNTs in thermal dissipation system for high power electronic devices, such as computer processor and high brightness light emitting diode (HB-LED). In this work, multiwalled carbon nanotubes (MWCNTs) based liquid was made by COOH functionalized MWCNTs dispersed in distilled water with concentration in the range between 0.2 and 1.2 gram/liter. MWCNT based liquid was used in liquid cooling system to enhance thermal dissipation for computer processor. By using distilled water in liquid cooling system, CPU's temperature decreases by about 10°C compared with using fan cooling system. By using MWCNT liquid with concentration of 1 gram/liter MWCNTs, the CPU's temperature decreases by 7°C compared with using distilled water in cooling system. Theoretically, we also showed that the presence of MWCNTs reduced thermal resistance and increased the thermal conductivity of liquid cooling system. The results have confirmed the advantages of the MWCNTs for thermal dissipation systems for the μ -processor and other high power electronic devices.

Surgical and Technical Modalities for Hearing Restoration in Ear Malformations.

PubMed

Dazert, Stefan; Thomas, Jan Peter; Volkenstein, Stefan

2015-12-01

Malformations of the external and middle ear often go along with an aesthetic and functional handicap. Independent of additional aesthetic procedures, a successful functional hearing restoration leads to a tremendous gain in quality of life for affected patients. The introduction of implantable hearing systems (bone conduction and middle ear devices) offers new therapeutic options in this field. We focus on functional rehabilitation of patients with malformations, either by surgical reconstruction or the use of different implantable hearing devices, depending on the disease itself and the severity of malformation as well as hearing impairment. Patients with an open ear canal and minor malformations are good candidates for surgical hearing restoration of middle ear structures with passive titanium or autologous implants. In cases with complete fibrous or bony atresia of the ear canal, the most promising functional outcome and gain in quality of life can be expected with an active middle ear implant or a bone conduction device combined with a surgical aesthetic rehabilitation in a single or multi-step procedure. Although the surgical procedure for bone conduction devices is straightforward and safe, more sophisticated operations for active middle ear implants (e.g., Vibrant Soundbridge, MED-EL, Innsbruck, Austria) provide an improved speech discrimination in noise and the ability of sound localization compared with bone conduction devices where the stimulation reaches both cochleae. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Interfacing with the nervous system: a review of current bioelectric technologies.

PubMed

Sahyouni, Ronald; Mahmoodi, Amin; Chen, Jefferson W; Chang, David T; Moshtaghi, Omid; Djalilian, Hamid R; Lin, Harrison W

2017-10-23

The aim of this study is to discuss the state of the art with regard to established or promising bioelectric therapies meant to alter or control neurologic function. We present recent reports on bioelectric technologies that interface with the nervous system at three potential sites-(1) the end organ, (2) the peripheral nervous system, and (3) the central nervous system-while exploring practical and clinical considerations. A literature search was executed on PubMed, IEEE, and Web of Science databases. A review of the current literature was conducted to examine functional and histomorphological effects of neuroprosthetic interfaces with a focus on end-organ, peripheral, and central nervous system interfaces. Innovations in bioelectric technologies are providing increasing selectivity in stimulating distinct nerve fiber populations in order to activate discrete muscles. Significant advances in electrode array design focus on increasing selectivity, stability, and functionality of implantable neuroprosthetics. The application of neuroprosthetics to paretic nerves or even directly stimulating or recording from the central nervous system holds great potential in advancing the field of nerve and tissue bioelectric engineering and contributing to clinical care. Although current physiotherapeutic and surgical treatments seek to restore function, structure, or comfort, they bear significant limitations in enabling cosmetic or functional recovery. Instead, the introduction of bioelectric technology may play a role in the restoration of function in patients with neurologic deficits.

The Automated System of the Rhythm Analysis of the Educational Process in a Higher Educational Institution on the Basis of Aprioristic Data

ERIC Educational Resources Information Center

Pelin, Nicolae; Mironov, Vladimir

2008-01-01

In this article the problems of functioning algorithms development for system of the automated analysis of educational process rhythm in a higher educational institution are considered. Using the device of experiment planning for conducting the scientific researches, adapted methodologies, received by authors in the dissertational works at the…

Effects of the Picture Exchange Communication System (PECS) on Maladaptive Behavior in Children with Autism Spectrum Disorders (ASD): A Review of the Literature

ERIC Educational Resources Information Center

Battaglia, Dana; McDonald, Mary E.

2015-01-01

This paper provides an overview of the literature investigating the functional relationship between the use of the Picture Exchange Communication System (PECS) and maladaptive behavior (i.e., aggression, tantrums) in individuals with autism spectrum disorders (ASD). Digital searches were conducted to identify single subject design studies…

Continuous control systems for non-contact ECG

NASA Astrophysics Data System (ADS)

Kodkin, Vladimir L.; Yakovleva, Galina V.; Smirnov, Alexey S.

2017-03-01

South Ural State University is still conducting the research work dedicated to innovations in biomedicine. Development of system for continuous control and diagnosis of the functional state in large groups of people is based on studies of non-contact ECG recording reported by the authors at the SPIE conference in 2016. The next stage of studies has been performed this year.

Evaluation of a voice recognition system for the MOTAS pseudo pilot station function

NASA Technical Reports Server (NTRS)

Houck, J. A.

1982-01-01

The Langley Research Center has undertaken a technology development activity to provide a capability, the mission oriented terminal area simulation (MOTAS), wherein terminal area and aircraft systems studies can be performed. An experiment was conducted to evaluate state-of-the-art voice recognition technology and specifically, the Threshold 600 voice recognition system to serve as an aircraft control input device for the MOTAS pseudo pilot station function. The results of the experiment using ten subjects showed a recognition error of 3.67 percent for a 48-word vocabulary tested against a programmed vocabulary of 103 words. After the ten subjects retrained the Threshold 600 system for the words which were misrecognized or rejected, the recognition error decreased to 1.96 percent. The rejection rates for both cases were less than 0.70 percent. Based on the results of the experiment, voice recognition technology and specifically the Threshold 600 voice recognition system were chosen to fulfill this MOTAS function.

Requirements for Workflow-Based EHR Systems - Results of a Qualitative Study.

PubMed

Schweitzer, Marco; Lasierra, Nelia; Hoerbst, Alexander

2016-01-01

Today's high quality healthcare delivery strongly relies on efficient electronic health records (EHR). These EHR systems or in general healthcare IT-systems are usually developed in a static manner according to a given workflow. Hence, they are not flexible enough to enable access to EHR data and to execute individual actions within a consultation. This paper reports on requirements pointed by experts in the domain of diabetes mellitus to design a system for supporting dynamic workflows to serve personalization within a medical activity. Requirements were collected by means of expert interviews. These interviews completed a conducted triangulation approach, aimed to gather requirements for workflow-based EHR interactions. The data from the interviews was analyzed through a qualitative approach resulting in a set of requirements enhancing EHR functionality from the user's perspective. Requirements were classified according to four different categorizations: (1) process-related requirements, (2) information needs, (3) required functions, (4) non-functional requirements. Workflow related requirements were identified which should be considered when developing and deploying EHR systems.

All printed touchless human-machine interface based on only five functional materials

NASA Astrophysics Data System (ADS)

Scheipl, G.; Zirkl, M.; Sawatdee, A.; Helbig, U.; Krause, M.; Kraker, E.; Andersson Ersman, P.; Nilsson, D.; Platt, D.; Bodö, P.; Bauer, S.; Domann, G.; Mogessie, A.; Hartmann, Paul; Stadlober, B.

2012-02-01

We demonstrate the printing of a complex smart integrated system using only five functional inks: the fluoropolymer P(VDF:TrFE) (Poly(vinylidene fluoride trifluoroethylene) sensor ink, the conductive polymer PEDOT:PSS (poly(3,4 ethylenedioxythiophene):poly(styrene sulfonic acid) ink, a conductive carbon paste, a polymeric electrolyte and SU8 for separation. The result is a touchless human-machine interface, including piezo- and pyroelectric sensor pixels (sensitive to pressure changes and impinging infrared light), transistors for impedance matching and signal conditioning, and an electrochromic display. Applications may not only emerge in human-machine interfaces, but also in transient temperature or pressure sensing used in safety technology, in artificial skins and in disposable sensor labels.

Negative Differential Conductance in Polyporphyrin Oligomers with Nonlinear Backbones.

PubMed

Kuang, Guowen; Chen, Shi Zhang; Yan, Linghao; Chen, Ke Qiu; Shang, Xuesong; Liu, Pei Nian; Lin, Nian

2018-01-17

We study negative differential conductance (NDC) effects in polyporphyrin oligomers with nonlinear backbones. Using a low-temperature scanning tunneling microscope, we selectively controlled the charge transport path in single oligomer wires. We observed robust NDC when charge passed through a T-shape junction, bistable NDC when charge passed through a 90° kink and no NDC when charge passed through a 120° kink. Aided by density functional theory with nonequilibrium Green's functions simulations, we attributed this backbone-dependent NDC to bias-modulated hybridization of the electrode states with the resonant transport molecular orbital. We argue this mechanism is generic in molecular systems, which opens a new route of designing molecular NDC devices.

Crescent evaluation : appendix E : crescent demonstration office : evaluation report

DOT National Transportation Integrated Search

1994-02-01

The purpose of this review was to conduct a limited audit to determine how well the Crescent Demonstration Office functions perform from the user perspective and what enhancements might be considered desirable or required in a long-term, system-wide ...

Integrated 3D bridge-condition visualization (BCV) to facilitate element-based bridge condition rating (EBCR).

DOT National Transportation Integrated Search

2015-11-01

Routine inspection and maintenance records are essential for bridges to function well throughout their intended lifespan. : Although existing bridge management systems are efficient at data storage, it is difficult to conduct comprehensive data : ana...

Temperature measurement and control system for transtibial prostheses: Functional evaluation.

PubMed

Ghoseiri, Kamiar; Zheng, Yong Ping; Leung, Aaron K L; Rahgozar, Mehdi; Aminian, Gholamreza; Lee, Tat Hing; Safari, Mohammad Reza

2018-01-01

The accumulation of heat inside the prosthetic socket increases skin temperature and fosters perspiration, which consequently leads to high tissue stress, friction blister, discomfort, unpleasant odor, and decreased prosthesis suspension and use. In the present study, the prototype of a temperature measurement and control (TM&C) system was designed, fabricated, and functionally evaluated in a phantom model of the transtibial prosthetic socket. The TM&C system was comprised of 12 thermistors divided equally into two groups that arranged internal and external to a prosthetic silicone liner. Its control system was programmed to select the required heating or cooling function of a thermal pump to provide thermal equilibrium based on the amount of temperature difference from a defined set temperature, or the amount of difference between the mean temperature recorded by inside and outside thermistors. A thin layer of aluminum was used for thermal conduction between the thermal pump and different sites around the silicone liner. The results showed functionality of the TM&C system for thermoregulation inside the prosthetic socket. However, enhancing the structure of this TM&C system, increasing its thermal power, and decreasing its weight and cost are main priorities before further development.

iACT - An interactive mHealth monitoring system to enhance psychotherapy for adolescents with sickle cell disease

PubMed Central

Cheng, Chihwen; Brown, R. Clark; Cohen, Lindsey L.; Venugopalan, Janani; Stokes, Todd H.

2016-01-01

Sickle cell disease (SCD) is the most common inherited disease, and SCD symptoms impact functioning and well-being. For example, adolescents with SCD have a higher tendency of psychological problems than the general population. Acceptance and Commitment Therapy (ACT), a cognitive-behavioral therapy, is an effective intervention to promote quality of life and functioning in adolescents with chronic illness. However, traditional visit-based therapy sessions are restrained by challenges, such as limited follow-up, insufficient data collection, low treatment adherence, and delayed intervention. In this paper, we present Instant Acceptance and Commitment Therapy (iACT), a system designed to enhance the quality of pediatric ACT. iACT utilizes text messaging technology, which is the most popular cell phone activity among adolescents, to conduct real-time psychotherapy interventions. The system is built on cloud computing technologies, which provides a convenient and cost-effective monitoring environment. To evaluate iACT, a trial with 60 adolescents with SCD is being conducted in conjunction with the Georgia Institute of Technology, Children’s Healthcare of Atlanta, and Georgia State University. PMID:24110179

iACT--an interactive mHealth monitoring system to enhance psychotherapy for adolescents with sickle cell disease.

PubMed

Cheng, Chihwen; Brown, R Clark; Cohen, Lindsey L; Venugopalan, Janani; Stokes, Todd H; Wang, May D

2013-01-01

Sickle cell disease (SCD) is the most common inherited disease, and SCD symptoms impact functioning and well-being. For example, adolescents with SCD have a higher tendency of psychological problems than the general population. Acceptance and Commitment Therapy (ACT), a cognitive-behavioral therapy, is an effective intervention to promote quality of life and functioning in adolescents with chronic illness. However, traditional visit-based therapy sessions are restrained by challenges, such as limited follow-up, insufficient data collection, low treatment adherence, and delayed intervention. In this paper, we present Instant Acceptance and Commitment Therapy (iACT), a system designed to enhance the quality of pediatric ACT. iACT utilizes text messaging technology, which is the most popular cell phone activity among adolescents, to conduct real-time psychotherapy interventions. The system is built on cloud computing technologies, which provides a convenient and cost-effective monitoring environment. To evaluate iACT, a trial with 60 adolescents with SCD is being conducted in conjunction with the Georgia Institute of Technology, Children's Healthcare of Atlanta, and Georgia State University.

Quantum transport through disordered 1D wires: Conductance via localized and delocalized electrons

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

Gopar, Víctor A.

Coherent electronic transport through disordered systems, like quantum wires, is a topic of fundamental and practical interest. In particular, the exponential localization of electron wave functions-Anderson localization-due to the presence of disorder has been widely studied. In fact, Anderson localization, is not an phenomenon exclusive to electrons but it has been observed in microwave and acoustic experiments, photonic materials, cold atoms, etc. Nowadays, many properties of electronic transport of quantum wires have been successfully described within a scaling approach to Anderson localization. On the other hand, anomalous localization or delocalization is, in relation to the Anderson problem, a less studiedmore » phenomenon. Although one can find signatures of anomalous localization in very different systems in nature. In the problem of electronic transport, a source of delocalization may come from symmetries present in the system and particular disorder configurations, like the so-called Lévy-type disorder. We have developed a theoretical model to describe the statistical properties of transport when electron wave functions are delocalized. In particular, we show that only two physical parameters determine the complete conductance distribution.« less

A Conceptual Project of a Device for Human Wrist Functional Rehabilitation

NASA Astrophysics Data System (ADS)

Lewandowski, B.; Olinski, M.; Wudarczyk, S.; Gronowicz, A.

2016-12-01

In the paper, the problems of devices supporting functional rehabilitation of a human wrist were addressed. A literature review and a description of selected devices together with an indication of their advantages and disadvantages were conducted. The biomechanical structure of a human wrist was analyzed. On this basis and after taking into consideration ranges of motion of the selected joints the concept of a new mechanism was developed. A 3D model of the device was built in the Autodesk Inventor system. For the purpose of simulations another model was developed in the MSC Adams system. Issues of drives and sensors selection, as well as requirements for the control system, were examined.

Using Technology to Facilitate Collaboration in Community-Based Participatory Research (CBPR)

PubMed Central

Jessell, Lauren; Smith, Vivian; Jemal, Alexis; Windsor, Liliane

2017-01-01

This study explores the use of Computer-Supported Collaborative Work (CSCW) technologies, by way of a computer-based system called iCohere. This system was used to facilitate collaboration conducting Community-Based Participatory Research (CBPR). Data was gathered from 13 members of a Community Collaborative Board (CCB). Analysis revealed that iCohere served the following functions: facilitating communication, providing a depository for information and resource sharing, and allowing for remote meeting attendance. Results indicated that while iCohere was useful in performing these functions, less expensive technologies had the potential to achieve similar goals if properly implemented. Implications for future research on CSCW systems and CBPR are discussed. PMID:29056871

Theoretical models for electron conduction in polymer systems—I. Macroscopic calculations of d.c. transient conductivity after pulse irradiation

NASA Astrophysics Data System (ADS)

Bartczak, Witold M.; Kroh, Jerzy

The simulation of the transient d.c. conductivity in a quasi one-dimensional system of charges produced by a pulse of ionizing radiation in a solid sample has been performed. The simulation is based on the macroscopic conductivity equations and can provide physical insight into d.c. conductivity measurements, particularly for the case of transient currents in samples with internal space charge. We consider the system of mobile (negative) and immobile (positive) charges produced by a pulse of ionizing radiation in the sample under a fixed external voltage V0. The presence of space charge results in an electric field which is a function of both the spatial and the time variable: E( z, t). Given the space charge density, the electric field can be calculated from the Poisson equation. However, for an arbitrary space charge distribution, the corresponding equations can only be solved numerically. The two non-trivial cases for which approximate analytical solutions can be provided are: (i) The density of the current carriers n( z, t) is negligible in comparison with the density of immobile space charge N( z). A general analytical solution has been found for this case using Green's functions. The solutions for two cases, viz. the homogeneous distribution of space charge N( z) = N, and the non-homogeneous exponential distribution N( z) = A exp(- Bz), have been separately discussed. (ii) The space charge created in the pulse without any space charge present prior to the irradiation.

Innovative Imagery System for Enhanced Habitability Onboard ISS: Desired Features and Possible Hardware Applications

NASA Technical Reports Server (NTRS)

Whitmore, Mihriban; Baggerman, Susan; Byrne, Vicky

2004-01-01

With the advent of the ISS and the experience of Russian, European, and US crewmembers on Mir, the importance of the psychological element in long duration missions is increasingly recognized. An integrated imagery system or Magic Window System could enhance the habitability, performance, and productivity for long term stays in space. Because this is type of system is a new concept for space, functional and technical requirements need to be determined. As part of a three-year project, the functional and technical requirements for an Imagery System onboard the International Space Station (ISS) have been explored. Valuable information was gathered from a survey completed by participants that had been in analog environments (remote/isolated) such as Antarctica, Aquarius, ISS crewmember debriefs, and crew support meetings to identify key functions desired for an integrated Magic Window System. Exercise and medical care activities were identified as areas that could benefit from such a system. It was determined that for exercise, it was worth exploring the concept of displaying a dynamic screen that changes as the crewmember's speed changes while showing physiological measures in a combined display. In terms of enhancing the interfaces for medical care activities, the Magic Window System could show video clips along side procedures for just-in-time training scenarios through a heads-up display. In addition, the portability, usability, and reliability were stressed as important considerations for an integrated system of technologies or Magic Window System. In addition, a review of state-of-the-art screens and other existing technologies such as tablet PCs and Personal Digital Assistants (PDAs) was conducted and contributed to defining technical requirements and feasibility of systems. Some heuristic evaluations of large displays and PDAs were conducted. Finally, feasibility for implementation onboard ISS has been considered. Currently, specific headset units are undergoing usability testing. The outcome of these activities will be valuable to determine the best candidates for an integrated system that could accommodate different needs depending on task.

Analytical gradients for subsystem density functional theory within the slater-function-based amsterdam density functional program.

PubMed

Schlüns, Danny; Franchini, Mirko; Götz, Andreas W; Neugebauer, Johannes; Jacob, Christoph R; Visscher, Lucas

2017-02-05

We present a new implementation of analytical gradients for subsystem density-functional theory (sDFT) and frozen-density embedding (FDE) into the Amsterdam Density Functional program (ADF). The underlying theory and necessary expressions for the implementation are derived and discussed in detail for various FDE and sDFT setups. The parallel implementation is numerically verified and geometry optimizations with different functional combinations (LDA/TF and PW91/PW91K) are conducted and compared to reference data. Our results confirm that sDFT-LDA/TF yields good equilibrium distances for the systems studied here (mean absolute deviation: 0.09 Å) compared to reference wave-function theory results. However, sDFT-PW91/PW91k quite consistently yields smaller equilibrium distances (mean absolute deviation: 0.23 Å). The flexibility of our new implementation is demonstrated for an HCN-trimer test system, for which several different setups are applied. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Reliability and Probabilistic Risk Assessment - How They Play Together

NASA Technical Reports Server (NTRS)

Safie, Fayssal M.; Stutts, Richard G.; Zhaofeng, Huang

2015-01-01

PRA methodology is one of the probabilistic analysis methods that NASA brought from the nuclear industry to assess the risk of LOM, LOV and LOC for launch vehicles. PRA is a system scenario based risk assessment that uses a combination of fault trees, event trees, event sequence diagrams, and probability and statistical data to analyze the risk of a system, a process, or an activity. It is a process designed to answer three basic questions: What can go wrong? How likely is it? What is the severity of the degradation? Since 1986, NASA, along with industry partners, has conducted a number of PRA studies to predict the overall launch vehicles risks. Planning Research Corporation conducted the first of these studies in 1988. In 1995, Science Applications International Corporation (SAIC) conducted a comprehensive PRA study. In July 1996, NASA conducted a two-year study (October 1996 - September 1998) to develop a model that provided the overall Space Shuttle risk and estimates of risk changes due to proposed Space Shuttle upgrades. After the Columbia accident, NASA conducted a PRA on the Shuttle External Tank (ET) foam. This study was the most focused and extensive risk assessment that NASA has conducted in recent years. It used a dynamic, physics-based, integrated system analysis approach to understand the integrated system risk due to ET foam loss in flight. Most recently, a PRA for Ares I launch vehicle has been performed in support of the Constellation program. Reliability, on the other hand, addresses the loss of functions. In a broader sense, reliability engineering is a discipline that involves the application of engineering principles to the design and processing of products, both hardware and software, for meeting product reliability requirements or goals. It is a very broad design-support discipline. It has important interfaces with many other engineering disciplines. Reliability as a figure of merit (i.e. the metric) is the probability that an item will perform its intended function(s) for a specified mission profile. In general, the reliability metric can be calculated through the analyses using reliability demonstration and reliability prediction methodologies. Reliability analysis is very critical for understanding component failure mechanisms and in identifying reliability critical design and process drivers. The following sections discuss the PRA process and reliability engineering in detail and provide an application where reliability analysis and PRA were jointly used in a complementary manner to support a Space Shuttle flight risk assessment.

Challenges to clinical deployment of upper limb neuroprostheses.

PubMed

Triolo, R; Nathan, R; Handa, Y; Keith, M; Betz, R R; Carroll, S; Kantor, C

1996-04-01

The technology for functional neuromuscular stimulation (FNS) as a means of providing upper limb function to people with tetraplegia has been under development by three clinical research groups for almost two decades. This paper presents the current status of the clinical trials of three FNS systems: a noninvasive system built into a cosmetic forearm splint, a 30-channel percutaneous system, and an 8-channel implantable system. The complexity of FNS systems and the unique characteristics of the individuals to whom they are applied combine to create many clinical and technical challenges that must be addressed before the devices can be deployed. The emerging challenges to widespread clinical introduction of FNS systems for hand and arm function are identified and analyzed. In addition to the demands of designed and conducting the clinical trials to satisfy regulatory requirements, the lack of knowledge, skepticism, and the complacency on the part of potential FNS recipients, as well as of rehabilitation professionals, must be overcome through education and careful consideration of economic and societal factors in the design of clinical systems.

Functional Characterization of Two Novel Human Prostate Cancer Metastasis Related Genes

DTIC Science & Technology

2006-02-01

have been conducted with in vitro-derived genetic materials from both mammalian and nonmammalian systems (27-29), a major leap in functional genomic ...sequences present in one complimentary (31) or genomic (32) DNA library but absent in another. The advent of suppressive hybridization technique...control specimens different from the native tissue for subtractive genomic analysis in some studies has created many inconclusive results. Cell to cell

SOLID SOLUTION EFFECTS ON THE THERMAL PROPERTIES IN THE MgAl2O4-MgGa2O4

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

O'Hara, Kelley; Smith, Jeffrey D; Sander, Todd P.

Solid solution eects on thermal conductivity within the MgO-Al2O3-Ga2O3 system were studied. Samples with systematically varied additions of MgGa2O4 to MgAl2O4 were prepared and the laser ash technique was used to determine thermal diusivity at temperatures between 200C and 1300C. Heat capacity as a function of temperature from room temperature to 800C was also determined using dierential scanning calorimetry. Solid solution in the MgAl2O4-MgGa2O4 system decreases the thermal conductivity up to 1000C. At 200C thermal conductivity decreased 24% with a 5 mol% addition of MgGa2O4 to the system. At 1000C the thermal conductivity decreased 13% with a 5 mol% addition.more » Steady state calculations showed a 12.5% decrease in heat ux with 5 mol% MgGa2O4 considered across a 12 inch thickness.« less

Robot-Assisted Fracture Surgery: Surgical Requirements and System Design.

PubMed

Georgilas, Ioannis; Dagnino, Giulio; Tarassoli, Payam; Atkins, Roger; Dogramadzi, Sanja

2018-03-09

The design of medical devices is a complex and crucial process to ensure patient safety. It has been shown that improperly designed devices lead to errors and associated accidents and costs. A key element for a successful design is incorporating the views of the primary and secondary stakeholders early in the development process. They provide insights into current practice and point out specific issues with the current processes and equipment in use. This work presents how information from a user-study conducted in the early stages of the RAFS (Robot Assisted Fracture Surgery) project informed the subsequent development and testing of the system. The user needs were captured using qualitative methods and converted to operational, functional, and non-functional requirements based on the methods derived from product design and development. This work presents how the requirements inform a new workflow for intra-articular joint fracture reduction using a robotic system. It is also shown how the various elements of the system are developed to explicitly address one or more of the requirements identified, and how intermediate verification tests are conducted to ensure conformity. Finally, a validation test in the form of a cadaveric trial confirms the ability of the designed system to satisfy the aims set by the original research question and the needs of the users.

The Prabhakar or three parameter Mittag-Leffler function: Theory and application

NASA Astrophysics Data System (ADS)

Garra, Roberto; Garrappa, Roberto

2018-03-01

The Prabhakar function (namely, a three parameter Mittag-Leffler function) is investigated. This function plays a fundamental role in the description of the anomalous dielectric properties in disordered materials and heterogeneous systems manifesting simultaneous nonlocality and nonlinearity and, more generally, in models of Havriliak-Negami type. After reviewing some of the main properties of the function, the asymptotic expansion for large arguments is investigated in the whole complex plane and, with major emphasis, along the negative semi-axis. Fractional integral and derivative operators of Prabhakar type are hence considered and some nonlinear heat conduction equations with memory involving Prabhakar derivatives are studied.

Partial regularity of weak solutions to a PDE system with cubic nonlinearity

NASA Astrophysics Data System (ADS)

Liu, Jian-Guo; Xu, Xiangsheng

2018-04-01

In this paper we investigate regularity properties of weak solutions to a PDE system that arises in the study of biological transport networks. The system consists of a possibly singular elliptic equation for the scalar pressure of the underlying biological network coupled to a diffusion equation for the conductance vector of the network. There are several different types of nonlinearities in the system. Of particular mathematical interest is a term that is a polynomial function of solutions and their partial derivatives and this polynomial function has degree three. That is, the system contains a cubic nonlinearity. Only weak solutions to the system have been shown to exist. The regularity theory for the system remains fundamentally incomplete. In particular, it is not known whether or not weak solutions develop singularities. In this paper we obtain a partial regularity theorem, which gives an estimate for the parabolic Hausdorff dimension of the set of possible singular points.

The Lattice and Thermal Radiation Conductivity of Thermal Barrier Coatings: Models and Experiments

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Spuckler, Charles M.

2010-01-01

The lattice and radiation conductivity of ZrO2-Y2O3 thermal barrier coatings was evaluated using a laser heat flux approach. A diffusion model has been established to correlate the coating apparent thermal conductivity to the lattice and radiation conductivity. The radiation conductivity component can be expressed as a function of temperature, coating material scattering, and absorption properties. High temperature scattering and absorption of the coating systems can be also derived based on the testing results using the modeling approach. A comparison has been made for the gray and nongray coating models in the plasma-sprayed thermal barrier coatings. The model prediction is found to have a good agreement with experimental observations.

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

Takaki, Hirokazu; Kobayashi, Kazuaki; Shimono, Masato

We present the thermoelectric properties of TiN/MgO superlattices employing first-principles calculation techniques. The Seebeck coefficients, the electrical conductances, the thermal conductances, and the figure of merit are investigated employing electrical and thermal transport calculations based on density functional theory combined with the nonequilibrium Green's function and nonequilibrium molecular dynamics simulation methods. The TiN/MgO superlattices with a small lattice mismatch at the interfaces are ideal systems to study the way for an enhancement of thermoelectric properties in artificial nanostructures. We find that the interfacial scattering between the two materials in the metal/insulator superlattices causes the electrical conductance to change rapidly, whichmore » enhances the Seebeck coefficient significantly. We show that the figure of merit for the artificial superlattice nanostructures has a much larger value compared with that of the bulk material and changes drastically with the superlattice configurations at the atomistic level.« less

Permittivity and conductivity parameter estimations using full waveform inversion

NASA Astrophysics Data System (ADS)

Serrano, Jheyston O.; Ramirez, Ana B.; Abreo, Sergio A.; Sadler, Brian M.

2018-04-01

Full waveform inversion of Ground Penetrating Radar (GPR) data is a promising strategy to estimate quantitative characteristics of the subsurface such as permittivity and conductivity. In this paper, we propose a methodology that uses Full Waveform Inversion (FWI) in time domain of 2D GPR data to obtain highly resolved images of the permittivity and conductivity parameters of the subsurface. FWI is an iterative method that requires a cost function to measure the misfit between observed and modeled data, a wave propagator to compute the modeled data and an initial velocity model that is updated at each iteration until an acceptable decrease of the cost function is reached. The use of FWI with GPR are expensive computationally because it is based on the computation of the electromagnetic full wave propagation. Also, the commercially available acquisition systems use only one transmitter and one receiver antenna at zero offset, requiring a large number of shots to scan a single line.

Thermal conductivity of graphene and graphite: collective excitations and mean free paths.

PubMed

Fugallo, Giorgia; Cepellotti, Andrea; Paulatto, Lorenzo; Lazzeri, Michele; Marzari, Nicola; Mauri, Francesco

2014-11-12

We characterize the thermal conductivity of graphite, monolayer graphene, graphane, fluorographane, and bilayer graphene, solving exactly the Boltzmann transport equation for phonons, with phonon-phonon collision rates obtained from density functional perturbation theory. For graphite, the results are found to be in excellent agreement with experiments; notably, the thermal conductivity is 1 order of magnitude larger than what found by solving the Boltzmann equation in the single mode approximation, commonly used to describe heat transport. For graphene, we point out that a meaningful value of intrinsic thermal conductivity at room temperature can be obtained only for sample sizes of the order of 1 mm, something not considered previously. This unusual requirement is because collective phonon excitations, and not single phonons, are the main heat carriers in these materials; these excitations are characterized by mean free paths of the order of hundreds of micrometers. As a result, even Fourier's law becomes questionable in typical sample sizes, because its statistical nature makes it applicable only in the thermodynamic limit to systems larger than a few mean free paths. Finally, we discuss the effects of isotopic disorder, strain, and chemical functionalization on thermal performance. Only chemical functionalization is found to play an important role, decreasing the conductivity by a factor of 2 in hydrogenated graphene, and by 1 order of magnitude in fluorogenated graphene.

Electronic nose for detecting multiple targets

NASA Astrophysics Data System (ADS)

Chakraborty, Anirban; Parthasarathi, Ganga; Poddar, Rakesh; Zhao, Weiqiang; Luo, Cheng

2006-05-01

The discovery of high conductivity in doped polyacetylene in 1977 (garnering the 2000 Nobel Prize in Chemistry for the three discovering scientists) has attracted considerable interest in the application of polymers as the semiconducting and conducting materials due to their promising potential to replace silicon and metals in building devices. Previous and current efforts in developing conducting polymer microsystems mainly focus on generating a device of a single function. When multiple micropatterns made of different conducting polymers are produced on the same substrate, many microsystems of multiple functions can be envisioned. For example, analogous to the mammalian olfactory system which includes over 1,000 receptor genes in detecting various odors (e.g., beer, soda etc.), a sensor consisting of multiple distinct conducting polymer sensing elements will be capable of detecting a number of analytes simultaneously. However, existing techniques present significant technical challenges of degradation, low throughput, low resolution, depth of field, and/or residual layer in producing conducting polymer microstructures. To circumvent these challenges, an intermediate-layer lithography method developed in our group is used to generate multiple micropatterns made of different, commonly used conducting polymers, Polypyrrole (PPy), Poly(3,4-ethylenedioxy)thiophene (PEDOT) and Polyaniline (PANI). The generated multiple micropatterns are further used in an "electronic nose" to detect water vapor, glucose, toluene and acetone.

Formulation of detailed consumables management models for the development (preoperational) period of advanced space transportation system: Executive summary

NASA Technical Reports Server (NTRS)

Torian, J. G.

1976-01-01

Formulation of models required for the mission planning and scheduling function and establishment of the relation of those models to prelaunch, onboard, ground support, and postmission functions for the development phase of space transportation systems (STS) was conducted. The preoperational space shuttle is used as the design baseline for the subject model formulations. Analytical models were developed which consist of a mission planning processor with appropriate consumables data base and a method of recognizing potential constraint violations in both the planning and flight operations functions. A flight data file for storage/retrieval of information over an extended period which interfaces with a flight operations processor for monitoring of the actual flights was examined.

14 CFR 1201.200 - General.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 20026. (e) For more detailed description of NASA's organizational structure, see the “U.S. Government..., and structure of the universe, the solar system, and the integrated functioning of the Earth. The...-occupied spacecraft, sounding rockets, balloons, aircraft, and ground-based research to conduct its...

Challenges associated with nerve conduction block using kilohertz electrical stimulation

NASA Astrophysics Data System (ADS)

Patel, Yogi A.; Butera, Robert J.

2018-06-01

Neuromodulation therapies, which electrically stimulate parts of the nervous system, have traditionally attempted to activate neurons or axons to restore function or alleviate disease symptoms. In stark contrast to this approach is inhibiting neural activity to relieve disease symptoms and/or restore homeostasis. One potential approach is kilohertz electrical stimulation (KES) of peripheral nerves—which enables a rapid, reversible, and localized block of conduction. This review highlights the existing scientific and clinical utility of KES and discusses the technical and physiological challenges that must be addressed for successful translation of KES nerve conduction block therapies.

Optical sensor for heat conduction measurement in biological tissue

NASA Astrophysics Data System (ADS)

Gutierrez-Arroyo, A.; Sanchez-Perez, C.; Aleman-Garcia, N.

2013-06-01

This paper presents the design of a heat flux sensor using an optical fiber system to measure heat conduction in biological tissues. This optoelectronic device is based on the photothermal beam deflection of a laser beam travelling in an acrylic slab this deflection is measured with a fiber optic angle sensor. We measure heat conduction in biological samples with high repeatability and sensitivity enough to detect differences in tissues from three chicken organs. This technique could provide important information of vital organ function as well as the detect modifications due to degenerative diseases or physical damage caused by medications or therapies.

Hypersonic Research Vehicle (HRV) real-time flight test support feasibility and requirements study. Part 2: Remote computation support for flight systems functions

NASA Technical Reports Server (NTRS)

Rediess, Herman A.; Hewett, M. D.

1991-01-01

The requirements are assessed for the use of remote computation to support HRV flight testing. First, remote computational requirements were developed to support functions that will eventually be performed onboard operational vehicles of this type. These functions which either cannot be performed onboard in the time frame of initial HRV flight test programs because the technology of airborne computers will not be sufficiently advanced to support the computational loads required, or it is not desirable to perform the functions onboard in the flight test program for other reasons. Second, remote computational support either required or highly desirable to conduct flight testing itself was addressed. The use is proposed of an Automated Flight Management System which is described in conceptual detail. Third, autonomous operations is discussed and finally, unmanned operations.

Combined application of extracorporeal membrane oxygenation and an artificial pacemaker in fulminant myocarditis in a child

PubMed Central

Ye, Sheng; Zhu, Lvchan; Ning, Botao; Zhang, Chenmei

2017-01-01

Fulminant myocarditis is severe and aggressive, but it is self-limited and usually has a favorable prognosis if the patients can survive the acute phase. When drug treatment is not effective, extracorporeal membrane oxygenation technology should be applied to support cardiopulmonary function. Extracorporeal membrane oxygenation can simultaneously support function of the left ventricle, right ventricle, and lungs, and provide stable blood circulation for patients with heart and respiratory failure, which allows sufficient time for the cardiopulmonary system to recover. Fulminant myocarditis affects cardiac systolic function, as well as the function of autorhythmic cells and the conduction system. If severe bradycardia or atrioventricular block appears, a pacemaker needs to be installed. We report a child with fulminant myocarditis who was treated with extracorporeal membrane oxygenation combined with an artificial pacemaker. PMID:28747842

Combined application of extracorporeal membrane oxygenation and an artificial pacemaker in fulminant myocarditis in a child.

PubMed

Ye, Sheng; Zhu, Lvchan; Ning, Botao; Zhang, Chenmei

2017-06-01

Fulminant myocarditis is severe and aggressive, but it is self-limited and usually has a favorable prognosis if the patients can survive the acute phase. When drug treatment is not effective, extracorporeal membrane oxygenation technology should be applied to support cardiopulmonary function. Extracorporeal membrane oxygenation can simultaneously support function of the left ventricle, right ventricle, and lungs, and provide stable blood circulation for patients with heart and respiratory failure, which allows sufficient time for the cardiopulmonary system to recover. Fulminant myocarditis affects cardiac systolic function, as well as the function of autorhythmic cells and the conduction system. If severe bradycardia or atrioventricular block appears, a pacemaker needs to be installed. We report a child with fulminant myocarditis who was treated with extracorporeal membrane oxygenation combined with an artificial pacemaker.

Maneuvering thermal conductivity of magnetic nanofluids by tunable magnetic fields

NASA Astrophysics Data System (ADS)

Patel, Jaykumar; Parekh, Kinnari; Upadhyay, R. V.

2015-06-01

We report an experimental investigation of magnetic field dependent thermal conductivity of a transformer oil base magnetic fluid as a function of volume fractions. In the absence of magnetic field, thermal conductivity increases linearly with an increase in volume fraction, and magnitude of thermal conductivity thus obtained is lower than that predicted by Maxwell's theory. This reveals the presence of clusters/oligomers in the system. On application of magnetic field, it exhibits a non-monotonous increase in thermal conductivity. The results are interpreted using the concept of a two-step homogenization method (which is based on differential effective medium theory). The results show a transformation of particle cluster configuration from long chain like prolate shape to the aggregated drop-like structure with increasing concentration as well as a magnetic field. The aggregated drop-like structure for concentrated system is supported by optical microscopic images. This shape change of clusters reduces thermal conductivity enhancement. Moreover, this structure formation is observed as a dynamic phenomenon, and at 226 mT field, the length of the structure extends with time, becomes maximum, and then reduces. This change results in the increase or decrease of thermal conductivity.

Thermal conductance of two interface materials and their applications in space systems

NASA Technical Reports Server (NTRS)

Scialdone, J. J.; Clatterbuck, C. H.; Wall, J. L.

1992-01-01

Two polymeric materials, the Cho-Therm 1671 elastomer and the CV-2946 conductive RTV silicone, have been evaluated. Tests were conducted in vacuum and in air, for many clamping pressures, power densities, and as a function of time. Results obtained show that the CV-2946 thermal conductance after 24 hour in vacuum is 0.62 W/sq cm C(4W/sq in C) when clamped with an average pressure of about 350 psi. The maximum conductance of Cho-Therm 1671 is 4.3 W/sq in C at the clamping pressure about 200 psi. After 72 h in vacuum, the conductance reaches a steady 3.4 W/sq in C, independent of clamping pressure. It is concluded that the tightly bolted, torqued fixtures do not buckle or distort and provide an optimum thermal conductance. The fixtures simulating an actual spacecraft configuration suffered severe bowing and separating, which caused considerable degradation of conductance values.

Microbial community assembly patterns under incipient conditions in a basaltic soil system

NASA Astrophysics Data System (ADS)

Sengupta, A.; Stegen, J.; Alves Meira Neto, A.; Wang, Y.; Chorover, J.; Troch, P. A. A.; Maier, R. M.

2017-12-01

In sub-surface environments, the biotic components are critically linked to the abiotic processes. However, there is limited understanding of community establishment, functional associations, and community assembly processes of such microbes in sub-surface environments. This study presents the first analysis of microbial signatures in an incipient terrestrial basalt soil system conducted under controlled conditions. A sub-meter scale sampling of a soil mesocosm revealed the contrasting distribution patterns of simple soil parameters such as bulk density and electrical conductivity. Phylogenetic analysis of 16S rRNA gene indicated the presence of a total 40 bacterial and archaeal phyla, with high relative abundance of Actinobacteria on the surface and highest abundance of Proteobacteria throughout the system. Community diversity patterns were inferred to be dependent on depth profile and average water content in the system. Predicted functional gene analysis suggested mixotrophy lifestyles with both autotrophic and heterotrophic metabolisms, likelihood of a unique salt tolerant methanogenic pathway with links to novel Euryarchea, signatures of an incomplete nitrogen cycle, and predicted enzymes of extracellular iron (II) to iron (III) conversion followed by intracellular uptake, transport and regulation. Null modeling revealed microbial community assembly was predominantly governed by variable selection, but the influence of the variable selection did not show systematic spatial structure. The presence of significant heterogeneity in predicted functions and ecologically deterministic shifts in community composition in a homogeneous incipient basalt highlights the complexity exhibited by microorganisms even in the simplest of environmental systems. This presents an opportunity to further develop our understanding of how microbial communities establish, evolve, impact, and respond in sub-surface environments.

Functional Flow and Event-Driven Methods for Predicting System Performance

DTIC Science & Technology

2015-09-01

The thesis process was difficult and at times painful , but the modeling applications were something that I thoroughly enjoyed working through and...21. 2. SAR Mission initiates; SAR Assets conduct search but no objects of interest are found; SAR assets continue to scan but OSC aborts mission...be related to the SAR, so the OSC aborts mission and all Assets RTB. 45 4. SAR Mission initiates; SAR Assets conduct search and find an object of

Conductance of finite systems and scaling in localization theory

NASA Astrophysics Data System (ADS)

Suslov, I. M.

2012-11-01

The conductance of finite systems plays a central role in the scaling theory of localization (Abrahams et al., Phys. Rev. Lett. 42, 673 (1979)). Usually it is defined by the Landauer-type formulas, which remain open the following questions: (a) exclusion of the contact resistance in the many-channel case; (b) correspondence of the Landauer conductance with internal properties of the system; (c) relation with the diffusion coefficient D(ω, q) of an infinite system. The answers to these questions are obtained below in the framework of two approaches: (1) self-consistent theory of localization by Vollhardt and Wölfle, and (2) quantum mechanical analysis based on the shell model. Both approaches lead to the same definition for the conductance of a finite system, closely related to the Thouless definition. In the framework of the self-consistent theory, the relations of finite-size scaling are derived and the Gell-Mann-Low functions β( g) for space dimensions d = 1, 2, 3 are calculated. In contrast to the previous attempt by Vollhardt and Wölfle (1982), the metallic and localized phase are considered from the same standpoint, and the conductance of a finite system has no singularity at the critical point. In the 2D case, the expansion of β( g) in 1/ g coincides with results of the σ-model approach on the two-loop level and depends on the renormalization scheme in higher loops; the use of dimensional regularization for transition to dimension d = 2 + ɛ looks incompatible with the physical essence of the problem. The results are compared with numerical and physical experiments. A situation in higher dimensions and the conditions for observation of the localization law σ(ω) ∝ - iω for conductivity are discussed.

Development of eddy current microscopy for high resolution electrical conductivity imaging using atomic force microscopy.

PubMed

Nalladega, V; Sathish, S; Jata, K V; Blodgett, M P

2008-07-01

We present a high resolution electrical conductivity imaging technique based on the principles of eddy current and atomic force microscopy (AFM). An electromagnetic coil is used to generate eddy currents in an electrically conducting material. The eddy currents generated in the conducting sample are detected and measured with a magnetic tip attached to a flexible cantilever of an AFM. The eddy current generation and its interaction with the magnetic tip cantilever are theoretically modeled using monopole approximation. The model is used to estimate the eddy current force between the magnetic tip and the electrically conducting sample. The theoretical model is also used to choose a magnetic tip-cantilever system with appropriate magnetic field and spring constant to facilitate the design of a high resolution electrical conductivity imaging system. The force between the tip and the sample due to eddy currents is measured as a function of the separation distance and compared to the model in a single crystal copper. Images of electrical conductivity variations in a polycrystalline dual phase titanium alloy (Ti-6Al-4V) sample are obtained by scanning the magnetic tip-cantilever held at a standoff distance from the sample surface. The contrast in the image is explained based on the electrical conductivity and eddy current force between the magnetic tip and the sample. The spatial resolution of the eddy current imaging system is determined by imaging carbon nanofibers in a polymer matrix. The advantages, limitations, and applications of the technique are discussed.

Quality of life of Greek patients with end stage renal disease undergoing haemodialysis.

PubMed

Kastrouni, Maria; Sarantopoulou, Eleni; Aperis, Georgios; Alivanis, Polichronis

2010-09-01

An evaluation of the quality of life of patients with end stage kidney disease undergoing haemodialysis in the Greek population was conducted to understand whether this quality could be improved. Comparisons were made with a similar study conducted in United States in regards to the effects of kidney disease in daily life, burden of kidney disease, work status, cognitive function, quality of social interaction, sexual function, social support, physical functioning, role physical on daily routine, pain, general health perceptions, role emotional, emotional well being, social function and energy/fatigue. Any differences are discussed and analysed. Sexual problems were found to be more prominent in this study, but the emotional status has greater influence in quality of life in the US study. The results were more positive in Greece with respect to dialysis staff encouragement, patient satisfaction, as well as acceptance and the understanding of illness. The results from our study reflect the differences of the health care systems in various countries as well as population-related beliefs and values.

Phonon scattering in nanoscale systems: lowest order expansion of the current and power expressions

NASA Astrophysics Data System (ADS)

Paulsson, Magnus; Frederiksen, Thomas; Brandbyge, Mads

2006-04-01

We use the non-equilibrium Green's function method to describe the effects of phonon scattering on the conductance of nano-scale devices. Useful and accurate approximations are developed that both provide (i) computationally simple formulas for large systems and (ii) simple analytical models. In addition, the simple models can be used to fit experimental data and provide physical parameters.

Real-time system for extracting and monitoring the cerebral functional component during fNIRS measurements

NASA Astrophysics Data System (ADS)

Yamada, Toru; Ohashi, Mitsuo; Umeyama, Shinji

2015-12-01

Functional near-infrared spectroscopy (fNIRS) can non-invasively detect hemodynamic changes associated with cerebral neural activation in human subjects. However, its signal is often affected by changes in the optical characteristics of tissues in the head other than brain. To conduct fNIRS measurements precisely and efficiently, the extraction and realtime monitoring of the cerebral functional component is crucial. We previously developed methods for extracting the cerebral functional component—the multidistance optode arrangement (MD) method and the hemodynamic modality separation (HMS) method. In this study, we implemented these methods in a software used with the fNIRS system OEG- 17APD (Spectratech, Japan), and realized a real-time display of the extracted results. When using this system for human subject experiments, the baselines obtained with the MD and HMS methods were highly stabilized, whereas originally, the fNIRS signal fluctuated significantly when the subject moved. Through a functional experiment with repetitive single-sided hand clasping tasks, the extracted signals showed distinctively higher reproducibility than that obtained in the conventional measurements.

Composing, Analyzing and Validating Software Models

NASA Astrophysics Data System (ADS)

Sheldon, Frederick T.

1998-10-01

This research has been conducted at the Computational Sciences Division of the Information Sciences Directorate at Ames Research Center (Automated Software Engineering Grp). The principle work this summer has been to review and refine the agenda that were carried forward from last summer. Formal specifications provide good support for designing a functionally correct system, however they are weak at incorporating non-functional performance requirements (like reliability). Techniques which utilize stochastic Petri nets (SPNs) are good for evaluating the performance and reliability for a system, but they may be too abstract and cumbersome from the stand point of specifying and evaluating functional behavior. Therefore, one major objective of this research is to provide an integrated approach to assist the user in specifying both functionality (qualitative: mutual exclusion and synchronization) and performance requirements (quantitative: reliability and execution deadlines). In this way, the merits of a powerful modeling technique for performability analysis (using SPNs) can be combined with a well-defined formal specification language. In doing so, we can come closer to providing a formal approach to designing a functionally correct system that meets reliability and performance goals.

Composing, Analyzing and Validating Software Models

NASA Technical Reports Server (NTRS)

Sheldon, Frederick T.

1998-01-01

This research has been conducted at the Computational Sciences Division of the Information Sciences Directorate at Ames Research Center (Automated Software Engineering Grp). The principle work this summer has been to review and refine the agenda that were carried forward from last summer. Formal specifications provide good support for designing a functionally correct system, however they are weak at incorporating non-functional performance requirements (like reliability). Techniques which utilize stochastic Petri nets (SPNs) are good for evaluating the performance and reliability for a system, but they may be too abstract and cumbersome from the stand point of specifying and evaluating functional behavior. Therefore, one major objective of this research is to provide an integrated approach to assist the user in specifying both functionality (qualitative: mutual exclusion and synchronization) and performance requirements (quantitative: reliability and execution deadlines). In this way, the merits of a powerful modeling technique for performability analysis (using SPNs) can be combined with a well-defined formal specification language. In doing so, we can come closer to providing a formal approach to designing a functionally correct system that meets reliability and performance goals.

Program Manager: Journal of the Defense Systems Management College. Volume 19, Number 1, January-February 1990

DTIC Science & Technology

1990-02-01

proposal to the HQ USAF than optimum communication be- While the report indicated that this recommended a long-range, integrated tween the user and the...SRA), conduct of The three functional Working Integrated logistics program plan- tradeoff studies, and development of Groups are separated into the...as well * INTEGRATION as a rapid retargeting capability. V. SYSTEM REQUIREMENTS Working Conditions At the same time, SAC realized that VI. SYSTEM

Comparison between reflectivity statistics at heights of 3 and 6 km and rain rate statistics at ground level

NASA Technical Reports Server (NTRS)

Crane, R. K.

1975-01-01

An experiment was conducted to study the relations between the empirical distribution functions of reflectivity at specified locations above the surface and the corresponding functions at the surface. A bistatic radar system was used to measure continuously the scattering cross section per unit volume at heights of 3 and 6 km. A frequency of 3.7 GHz was used in the tests. It was found that the distribution functions for reflectivity may significantly change with height at heights below the level of the melting layer.

Patterns and determinants of pathways to reach comprehensive emergency obstetric and neonatal care (CEmONC) in South Sudan: qualitative diagrammatic pathway analysis.

PubMed

Elmusharaf, Khalifa; Byrne, Elaine; AbuAgla, Ayat; AbdelRahim, Amal; Manandhar, Mary; Sondorp, Egbert; O'Donovan, Diarmuid

2017-08-29

Maternity referral systems have been under-documented, under-researched, and under-theorised. Responsive emergency referral systems and appropriate transportation are cornerstones in the continuum of care and central to the complex health system. The pathways that women follow to reach Emergency Obstetric and Neonatal Care (EmONC) once a decision has been made to seek care have received relatively little attention. The aim of this research was to identify patterns and determinants of the pathways pregnant women follow from the onset of labour or complications until they reach an appropriate health facility. This study was conducted in Renk County in South Sudan between 2010 and 2012. Data was collected using Critical Incident Technique (CIT) and stakeholder interviews. CIT systematically identified pathways to healthcare during labour, and factors associated with an event of maternal mortality or near miss through a series of in-depth interviews with witnesses or those involved. Face-to-face stakeholder interviews were conducted with 28 purposively identified key informants. Diagrammatic pathway and thematic analysis were conducted using NVIVO 10 software. Once the decision is made to seek emergency obstetric care, the pregnant woman may face a series of complex steps before she reaches an appropriate health facility. Four pathway patterns to CEmONC were identified of which three were associated with high rates of maternal death: late referral, zigzagging referral, and multiple referrals. Women who bypassed nonfunctional Basic EmONC facilities and went directly to CEmONC facilities (the fourth pathway pattern) were most likely to survive. Overall, the competencies of the providers and the functionality of the first point of service determine the pathway to further care. Our findings indicate that outcomes are better where there is no facility available than when the woman accesses a non-functioning facility, and the absence of a healthcare provider is better than the presence of a non-competent provider. Visiting non-functioning or partially functioning healthcare facilities on the way to competent providers places the woman at greater risk of dying. Non-functioning facilities and non-competent providers are likely to contribute to the deaths of women.

Conductive nanogel-interfaced neural microelectrode arrays with electrically controlled in-situ delivery of manganese ions enabling high-resolution MEMRI for synchronous neural tracing with deep brain stimulation.

PubMed

Huang, Wei-Chen; Lo, Yu-Chih; Chu, Chao-Yi; Lai, Hsin-Yi; Chen, You-Yin; Chen, San-Yuan

2017-04-01

Chronic brain stimulation has become a promising physical therapy with increased efficacy and efficiency in the treatment of neurodegenerative diseases. The application of deep brain electrical stimulation (DBS) combined with manganese-enhanced magnetic resonance imaging (MEMRI) provides an unbiased representation of the functional anatomy, which shows the communication between areas of the brain responding to the therapy. However, it is challenging for the current system to provide a real-time high-resolution image because the incorporated MnCl 2 solution through microinjection usually results in image blurring or toxicity due to the uncontrollable diffusion of Mn 2+ . In this study, we developed a new type of conductive nanogel-based neural interface composed of amphiphilic chitosan-modified poly(3,4 -ethylenedioxythiophene) (PMSDT) that can exhibit biomimic structural/mechanical properties and ionic/electrical conductivity comparable to that of Au. More importantly, the PMSDT enables metal-ligand bonding with Mn 2+ ions, so that the system can release Mn 2+ ions rather than MnCl 2 solution directly and precisely controlled by electrical stimulation (ES) to achieve real-time high-resolution MEMRI. With the integration of PMSDT nanogel-based coating in polyimide-based microelectrode arrays, the post-implantation DBS enables frequency-dependent MR imaging in vivo, as well as small focal imaging in response to channel site-specific stimulation on the implant. The MR imaging of the implanted brain treated with 5-min electrical stimulation showed a thalamocortical neuronal pathway after 36 h, confirming the effective activation of a downstream neuronal circuit following DBS. By eliminating the susceptibility to artifact and toxicity, this system, in combination with a MR-compatible implant and a bio-compliant neural interface, provides a harmless and synchronic functional anatomy for DBS. The study demonstrates a model of MEMRI-functionalized DBS based on functional neural interface engineering and controllable delivery technology, which can be utilized in more detailed exploration of the functional anatomy in the treatment of neurodegenerative diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

IDIMS/GEOPAK: Users manual for a geophysical data display and analysis system

NASA Technical Reports Server (NTRS)

Libert, J. M.

1982-01-01

The application of an existing image analysis system to the display and analysis of geophysical data is described, the potential for expanding the capabilities of such a system toward more advanced computer analytic and modeling functions is investigated. The major features of the IDIMS (Interactive Display and Image Manipulation System) and its applicability for image type analysis of geophysical data are described. Development of a basic geophysical data processing system to permit the image representation, coloring, interdisplay and comparison of geophysical data sets using existing IDIMS functions and to provide for the production of hard copies of processed images was described. An instruction manual and documentation for the GEOPAK subsystem was produced. A training course for personnel in the use of the IDIMS/GEOPAK was conducted. The effectiveness of the current IDIMS/GEOPAK system for geophysical data analysis was evaluated.

A new BP Fourier algorithm and its application in English teaching evaluation

NASA Astrophysics Data System (ADS)

Pei, Xuehui; Pei, Guixin

2017-08-01

BP neural network algorithm has wide adaptability and accuracy when used in complicated system evaluation, but its calculation defects such as slow convergence have limited its practical application. The paper tries to speed up the calculation convergence of BP neural network algorithm with Fourier basis functions and presents a new BP Fourier algorithm for complicated system evaluation. First, shortages and working principle of BP algorithm are analyzed for subsequent targeted improvement; Second, the presented BP Fourier algorithm adopts Fourier basis functions to simplify calculation structure, designs new calculation transfer function between input and output layers, and conducts theoretical analysis to prove the efficiency of the presented algorithm; Finally, the presented algorithm is used in evaluating university English teaching and the application results shows that the presented BP Fourier algorithm has better performance in calculation efficiency and evaluation accuracy and can be used in evaluating complicated system practically.

Modeling transport kinetics in clinoptilolite-phosphate rock systems

NASA Technical Reports Server (NTRS)

Allen, E. R.; Ming, D. W.; Hossner, L. R.; Henninger, D. L.

1995-01-01

Nutrient release in clinoptilolite-phosphate rock (Cp-PR) systems occurs through dissolution and cation-exchange reactions. Investigating the kinetics of these reactions expands our understanding of nutrient release processes. Research was conducted to model transport kinetics of nutrient release in Cp-PR systems. The objectives were to identify empirical models that best describe NH4, K, and P release and define diffusion-controlling processes. Materials included a Texas clinoptilolite (Cp) and North Carolina phosphate rock (PR). A continuous-flow thin-disk technique was used. Models evaluated included zero order, first order, second order, parabolic diffusion, simplified Elovich, Elovich, and power function. The power-function, Elovich, and parabolic-diffusion models adequately described NH4, K, and P release. The power-function model was preferred because of its simplicity. Models indicated nutrient release was diffusion controlled. Primary transport processes controlling nutrient release for the time span observed were probably the result of a combination of several interacting transport mechanisms.

Design of Power System Architectures for Small Spacecraft Systems

NASA Technical Reports Server (NTRS)

Momoh, James A.; Subramonian, Rama; Dias, Lakshman G.

1996-01-01

The objective of this research is to perform a trade study on several candidate power system architectures for small spacecrafts to be used in NASA's new millennium program. Three initial candidate architectures have been proposed by NASA and two other candidate architectures have been proposed by Howard University. Howard University is currently conducting the necessary analysis, synthesis, and simulation needed to perform the trade studies and arrive at the optimal power system architecture. Statistical, sensitivity and tolerant studies has been performed on the systems. It is concluded from present studies that certain components such as the series regulators, buck-boost converters and power converters can be minimized while retaining the desired functionality of the overall architecture. This in conjunction with battery scalability studies and system efficiency studies have enabled us to develop more economic architectures. Future studies will include artificial neural networks and fuzzy logic to analyze the performance of the systems. Fault simulation studies and fault diagnosis studies using EMTP and artificial neural networks will also be conducted.

Electric Conductivity in a Beam, Plasma System.

DTIC Science & Technology

1977-09-15

Green ’s function solution to the Boltzmann equation and arrived at a stationary state. However Balescu has accounted for the potential energy of...R. Balescu , Statistical Mechanics of Charged Particles , (In terscience Publishers , New York , 1963) 21. P.M. Morse and H. Feshbach, Methods of

77 FR 5804 - Statement of Organization, Functions, and Delegations of Authority

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-06

... organizations; (5) plans, directs, and conducts epidemiologic and evaluative investigations and interventions to... support to NCCDPHP scientific authors; (9) designs, develops, and coordinates the publication of print and... avenues; (3) designs, coordinates, and funds regional and national surveillance systems and population...

Building an Online Learning Community

ERIC Educational Resources Information Center

Chen, Yu-Chein

2004-01-01

The Internet was not invented for education at beginning (Pett Grabinger, 1995), but it has influenced educational systems considerably, especially by providing another way for distance learning. This powerful communication function is superior to any other educational media. Students can conduct their own self-directed learning without…

Redefining plant functional types for forests based on plant traits

NASA Astrophysics Data System (ADS)

Wei, L.; Xu, C.; Christoffersen, B. O.; McDowell, N. G.; Zhou, H.

2016-12-01

Our ability to predict forest mortality is limited by the simple plant functional types (PFTs) in current generations of Earth System models (ESMs). For example, forests were formerly separated into PFTs only based on leaf form and phenology across different regions (arctic, temperate, and tropic areas) in the Community Earth System Model (CESM). This definition of PFTs ignored the large variation in vulnerability of species to drought and shade tolerance within each PFT. We redefined the PFTs for global forests based on plant traits including phenology, wood density, leaf mass per area, xylem-specific conductivity, and xylem pressure at 50% loss of conductivity. Species with similar survival strategies were grouped into the same PFT. New PFTs highlighted variation in vulnerability and physiological adaptation to drought and shade. New PFTs were better clustered than old ones in the two-dimensional plane of the first two principle components in a principle component analysis. We expect that the new PFTs will strengthen ESMs' ability on predicting drought-induced mortality in the future.

Expert Assessment of Conditions for Accredited Quality Management System Functioning in Testing Laboratories

NASA Astrophysics Data System (ADS)

Mytych, Joanna; Ligarski, Mariusz J.

2018-03-01

The quality management systems compliant with the ISO 9001:2009 have been thoroughly researched and described in detail in the world literature. The accredited management systems used in the testing laboratories and compliant with the ISO/IEC 17025:2005 have been mainly described in terms of the system design and implementation. They have also been investigated from the analytical point of view. Unfortunately, a low number of studies concerned the management system functioning in the accredited testing laboratories. The aim of following study was to assess the management system functioning in the accredited testing laboratories in Poland. On 8 October 2015, 1,213 accredited testing laboratories were present in Poland. They investigated various scientific areas and substances/objects. There are more and more such laboratories that have various problems and different long-term experience when it comes to the implementation, maintenance and improvement of the management systems. The article describes the results of the conducted expert assessment (survey) carried out to examine the conditions for the functioning of a management system in an accredited laboratory. It also focuses on the characteristics of the accredited research laboratories in Poland. The authors discuss the selection of the external and internal conditions that may affect the accredited management system. They show how the experts assessing the selected conditions were chosen. The survey results are also presented.

Computer simulation of thermal conductivity in vulcanized polyisoprene at variable strain and temperature

NASA Astrophysics Data System (ADS)

Engelmann, Sven; Meyer, Jan; Hentschke, Reinhard

2017-08-01

We study the thermal conductivity tensor in an atomistic model of vulcanized cis-1,4-polyisoprene (PI) rubber via molecular dynamics simulations. Our polymer force field is based on V. A. Harmandaris et al. [J. Chem. Phys. 116, 436 (2002), 10.1063/1.1416872], whereas the polymerization algorithm follows the description in J. Hager et al. [Macromolecules 48, 9039 (2015), 10.1021/acs.macromol.5b01864]. The polymer chains are chemically cross linked via sulfur bridges of adjustable cross-link density. A volume-conserving uniaxial strain of up to 200% is applied to the systems. The widely used GROMACS simulation package is adapted to allow using the Green-Kubo approach to calculate the thermal conductivity tensor components. Our analysis of the heat flux autocorrelation functions leads to the conclusion that the thermal conductivity in PI is governed by short-lived phonon modes at low wave numbers due to deformation of the monomers along the polymer backbone. Applying uniaxial strain causes increased orientation of monomers along the strain direction, which enhances the attendant thermal conductivity component. We find an exponential increase of the conductivity in stretch direction in terms of an attendant orientation order parameter. This is accompanied by a simultaneous decline of thermal conductivity in the orthogonal directions. Increase of the cross-link density only has a weak effect on thermal conductivity in the unstrained system, even at high cross-link density. In the strained system we do observed a rising thermal conductivity in the limit of high stress. This increase is attributed to enhanced coupling between chains rather than to their orientation.

Electrical Transport Properties of Liquid Al-Cu Alloys

NASA Astrophysics Data System (ADS)

Thakore, B. Y.; Khambholja, S. G.; Suthar, P. H.; Jani, A. R.

2010-06-01

Electrical transport properties viz. electrical resistivity, thermoelectric power and thermal conductivity of liquid Al-Cu alloys as a function of Cu concentration have been studied in the present paper. Ashcroft empty core model potential has been used to incorporate the ion-electron interaction. To incorporate the exchange and correlation effects, five different forms of local field correction functions viz. Hartree, Taylor, Ichimaru et al., Farid et al. and Sarkar et al. have been used. The transport properties of binary system have been studied using Faber-Ziman formulation combined with Ashcroft-Langreth (AL) partial structure factor. The computed values of electrical resistivity are compared with experimental data and for low Cu concentration, good agreement has been observed. Further, thermoelectric power and thermal conductivity have also been predicted.

Cross-plane thermal conductivity of (Ti,W)N/(Al,Sc)N metal/semiconductor superlattices

NASA Astrophysics Data System (ADS)

Saha, Bivas; Koh, Yee Rui; Comparan, Jonathan; Sadasivam, Sridhar; Schroeder, Jeremy L.; Garbrecht, Magnus; Mohammed, Amr; Birch, Jens; Fisher, Timothy; Shakouri, Ali; Sands, Timothy D.

2016-01-01

Reduction of cross-plane thermal conductivity and understanding of the mechanisms of heat transport in nanostructured metal/semiconductor superlattices are crucial for their potential applications in thermoelectric and thermionic energy conversion devices, thermal management systems, and thermal barrier coatings. We have developed epitaxial (Ti,W)N/(Al,Sc)N metal/semiconductor superlattices with periodicity ranging from 1 nm to 240 nm that show significantly lower thermal conductivity compared to the parent TiN/(Al,Sc)N superlattice system. The (Ti,W)N/(Al,Sc)N superlattices grow with [001] orientation on the MgO(001) substrates with well-defined coherent layers and are nominally single crystalline with low densities of extended defects. Cross-plane thermal conductivity (measured by time-domain thermoreflectance) decreases with an increase in the superlattice interface density in a manner that is consistent with incoherent phonon boundary scattering. Thermal conductivity values saturate at 1.7 W m-1K-1 for short superlattice periods possibly due to a delicate balance between long-wavelength coherent phonon modes and incoherent phonon scattering from heavy tungsten atomic sites and superlattice interfaces. First-principles density functional perturbation theory based calculations are performed to model the vibrational spectrum of the individual component materials, and transport models are used to explain the interface thermal conductance across the (Ti,W)N/(Al,Sc)N interfaces as a function of periodicity. The long-wavelength coherent phonon modes are expected to play a dominant role in the thermal transport properties of the short-period superlattices. Our analysis of the thermal transport properties of (Ti,W)N/(Al,Sc)N metal/semiconductor superlattices addresses fundamental questions about heat transport in multilayer materials.

A methodology for commonality analysis, with applications to selected space station systems

NASA Technical Reports Server (NTRS)

Thomas, Lawrence Dale

1989-01-01

The application of commonality in a system represents an attempt to reduce costs by reducing the number of unique components. A formal method for conducting commonality analysis has not been established. In this dissertation, commonality analysis is characterized as a partitioning problem. The cost impacts of commonality are quantified in an objective function, and the solution is that partition which minimizes this objective function. Clustering techniques are used to approximate a solution, and sufficient conditions are developed which can be used to verify the optimality of the solution. This method for commonality analysis is general in scope. It may be applied to the various types of commonality analysis required in the conceptual, preliminary, and detail design phases of the system development cycle.

Pharmaceutical composition and drug effect of synthetic Bacopa monnieri L. health promoting agent from the perspective of resistance fatigue.

PubMed

Chen, Zhidan; Yan, Yanqin

2017-09-01

Bacopa monnieri has effect on the nervous system, digestive system and blood circulation systems. In this paper, the authors conducted pharmacological analysis on Bacopa monniera and its innovative pharmaceutical preparation of promote motor function. The extract of the drug has some effect on relieving the fatigue and providing the movement function. By analyzing the composition and efficacy of Chinese herbal extracts, it can be seen that these drugs have obvious effect on improving immunity. Experimental results show that the agent can increase the liver glycogen energy reserves, reduce Bla and BUN levels, balance and energy metabolism of muscle cells in the environment, it plays a positive role to improve the exercise capacity and exercise fatigue.

Some system considerations in configuring a digital flight control - navigation system

NASA Technical Reports Server (NTRS)

Boone, J. H.; Flynn, G. R.

1976-01-01

A trade study was conducted with the objective of providing a technical guideline for selection of the most appropriate computer technology for the automatic flight control system of a civil subsonic jet transport. The trade study considers aspects of using either an analog, incremental type special purpose computer or a general purpose computer to perform critical autopilot computation functions. It also considers aspects of integration of noncritical autopilot and autothrottle modes into the computer performing the critical autoland functions, as compared to the federation of the noncritical modes into either a separate computer or with a R-Nav computer. The study is accomplished by establishing the relative advantages and/or risks associated with each of the computer configurations.

Study to define low voltage and low temperature operating limits of the Pioneer 10/11 Meteoroid Detection Equipment (MDE) system

NASA Technical Reports Server (NTRS)

Parker, C. D.

1975-01-01

The Pioneer 10/11 meteoroid detection equipment (MDE) pressure cells were tested at liquid nitrogen (LN2) and liquid helium (LHe) temperatures with the excitation voltage controlled as a parameter. The cells failed by firing because of pressurizing gas condensation as the temperature was lowered from LN2 to LHe temperature and when raised from LHe temperature. A study was conducted to determine cell pressure as a function of temperature, and cell failure was estimated as a function of temperature and excitation voltage. The electronic system was also studied, and a profile of primary spacecraft voltage (nominally 28 Vdc) and temperature corresponding to electronic system failure was determined experimentally.

HSI top-down requirements analysis for ship manpower reduction

NASA Astrophysics Data System (ADS)

Malone, Thomas B.; Bost, J. R.

2000-11-01

U.S. Navy ship acquisition programs such as DD 21 and CVNX are increasingly relying on top down requirements analysis (TDRA) to define and assess design approaches for workload and manpower reduction, and for ensuring required levels of human performance, reliability, safety, and quality of life at sea. The human systems integration (HSI) approach to TDRA begins with a function analysis which identifies the functions derived from the requirements in the Operational Requirements Document (ORD). The function analysis serves as the function baseline for the ship, and also supports the definition of RDT&E and Total Ownership Cost requirements. A mission analysis is then conducted to identify mission scenarios, again based on requirements in the ORD, and the Design Reference Mission (DRM). This is followed by a mission/function analysis which establishes the function requirements to successfully perform the ship's missions. Function requirements of major importance for HSI are information, performance, decision, and support requirements associated with each function. An allocation of functions defines the roles of humans and automation in performing the functions associated with a mission. Alternate design concepts, based on function allocation strategies, are then described, and task networks associated with the concepts are developed. Task network simulations are conducted to assess workloads and human performance capabilities associated with alternate concepts. An assessment of the affordability and risk associated with alternate concepts is performed, and manning estimates are developed for feasible design concepts.

Evaluation of high temperature superconductive thermal bridges for space borne cryogenic detectors

NASA Technical Reports Server (NTRS)

Scott, Elaine P.

1996-01-01

Infrared sensor satellites are used to monitor the conditions in the earth's upper atmosphere. In these systems, the electronic links connecting the cryogenically cooled infrared detectors to the significantly warmer amplification electronics act as thermal bridges and, consequently, the mission lifetimes of the satellites are limited due to cryogenic evaporation. High-temperature superconductor (HTS) materials have been proposed by researchers at the National Aeronautics and Space Administration Langley's Research Center (NASA-LaRC) as an alternative to the currently used manganin wires for electrical connection. The potential for using HTS films as thermal bridges has provided the motivation for the design and the analysis of a spaceflight experiment to evaluate the performance of this superconductive technology in the space environment. The initial efforts were focused on the preliminary design of the experimental system which allows for the quantitative comparison of superconductive leads with manganin leads, and on the thermal conduction modeling of the proposed system. Most of the HTS materials were indicated to be potential replacements for the manganin wires. In the continuation of this multi-year research, the objectives of this study were to evaluate the sources of heat transfer on the thermal bridges that have been neglected in the preliminary conductive model and then to develop a methodology for the estimation of the thermal conductivities of the HTS thermal bridges in space. The Joule heating created by the electrical current through the manganin wires was incorporated as a volumetric heat source into the manganin conductive model. The radiative heat source on the HTS thermal bridges was determined by performing a separate radiant interchange analysis within a high-T(sub c) superconductor housing area. Both heat sources indicated no significant contribution on the cryogenic heat load, which validates the results obtained in the preliminary conduction model. A methodology was presented for the estimation of the thermal conductivities of the individual HTS thermal bridge materials and the effective thermal conductivities of the composite HTS thermal bridges as functions of temperature. This methodology included a sensitivity analysis and the demonstration of the estimation procedure using simulated data with added random errors. The thermal conductivities could not be estimated as functions of temperature; thus the effective thermal conductivities of the HTS thermal bridges were analyzed as constants.

A Comparison of Peak Electric Fields and GICs in the Pacific Northwest Using 1-D and 3-D Conductivity

NASA Astrophysics Data System (ADS)

Gannon, J. L.; Birchfield, A. B.; Shetye, K. S.; Overbye, T. J.

2017-11-01

Geomagnetically induced currents (GICs) are a result of the changing magnetic fields during a geomagnetic disturbance interacting with the deep conductivity structures of the Earth. When assessing GIC hazard, it is a common practice to use layer-cake or one-dimensional conductivity models to approximate deep Earth conductivity. In this paper, we calculate the electric field and estimate GICs induced in the long lines of a realistic system model of the Pacific Northwest, using the traditional 1-D models, as well as 3-D models represented by Earthscope's Electromagnetic transfer functions. The results show that the peak electric field during a given event has considerable variation across the analysis region in the Pacific Northwest, but the 1-D physiographic approximations may accurately represent the average response of an area, although corrections are needed. Rotations caused by real deep Earth conductivity structures greatly affect the direction of the induced electric field. This effect may be just as, or more, important than peak intensity when estimating GICs induced in long bulk power system lines.

Conductance spectra of asymmetric ferromagnet/ferromagnet/ferromagnet junctions

NASA Astrophysics Data System (ADS)

Pasanai, K.

2017-01-01

A theory of tunneling spectroscopy of ferromagnet/ferromagnet/ferromagnet junctions was studied. We applied a delta-functional approximation for the interface scattering properties under a one-dimensional system of a free electron approach. The reflection and transmission probabilities were calculated in the ballistic regime, and the conductance spectra were then calculated using the Landauer formulation. The magnetization directions were set to be either parallel (P) or anti-parallel (AP) alignments, for comparison. We found that the conductance spectra was suppressed when increasing the interfacial scattering at the interfaces. Moreover, the electron could exhibit direct transmission when the thickness was rather thin. Thus, there was no oscillation in this case. However, in the case of a thick layer the conductance spectra oscillated, and this oscillation was most prominent when the middle layer thickness increased. In the case of direct transmission, the conductance spectra of P and AP systems were definitely suppressed with increased exchange energy of the middle ferromagnet. This also refers to an increase in the magnetoresistance of the junction. In the case of oscillatory behavior, the positions of the resonance peaks were changed as the exchange energy was changed.

An Efficient numerical method to calculate the conductivity tensor for disordered topological matter

NASA Astrophysics Data System (ADS)

Garcia, Jose H.; Covaci, Lucian; Rappoport, Tatiana G.

2015-03-01

We propose a new efficient numerical approach to calculate the conductivity tensor in solids. We use a real-space implementation of the Kubo formalism where both diagonal and off-diagonal conductivities are treated in the same footing. We adopt a formulation of the Kubo theory that is known as Bastin formula and expand the Green's functions involved in terms of Chebyshev polynomials using the kernel polynomial method. Within this method, all the computational effort is on the calculation of the expansion coefficients. It also has the advantage of obtaining both conductivities in a single calculation step and for various values of temperature and chemical potential, capturing the topology of the band-structure. Our numerical technique is very general and is suitable for the calculation of transport properties of disordered systems. We analyze how the method's accuracy varies with the number of moments used in the expansion and illustrate our approach by calculating the transverse conductivity of different topological systems. T.G.R, J.H.G and L.C. acknowledge Brazilian agencies CNPq, FAPERJ and INCT de Nanoestruturas de Carbono, Flemish Science Foundation for financial support.

Phonon scattering mechanisms dictating the thermal conductivity of lead zirconate titanate (PbZr 1- xTi xO 3) thin films across the compositional phase diagram

DOE PAGES

Foley, Brian M.; Paisley, Elizabeth A.; DiAntonio, Christopher; ...

2017-05-23

This paper represents a thorough investigation of the thermal conductivity (κ) in both thin film and bulk PbZr 1–xTi xO 3 (PZT) across the compositional phase diagram. Given the technological importance of PZT as a superb piezoelectric and ferroelectric material in devices and systems impacting a wide array of industries, this research serves to fill the gap in knowledge regarding the thermal properties. The thermal conductivities of both thin film and bulk PZT are found to vary by a considerable margin as a function of composition x. Additionally, we observe a discontinuity in κ in the vicinity of the morphotropicmore » phase boundary (MPB, x = 0.48) where there is a 20%–25% decrease in κ in our thin film data, similar to that found in literature data for bulk PZT. The comparison between bulk and thin film materials highlights the sensitivity of κ to size effects such as film thickness and grain size even in disordered alloy/solid-solution materials. A model for the thermal conductivity of PZT as a function of composition (κ(x)) is presented, which enables the application of the virtual crystal approximation for alloy-type material systems with very different crystals structures, resulting in differing temperature trends for κ. We show that in the case of crystalline solid-solutions where the thermal conductivity of one of the parent materials exhibits glass-like temperature trends the compositional dependence of thermal conductivity is relatively constant for most values of x. Finally, this is in stark contrast with the typical trends of thermal conductivity with x in alloys, where the thermal conductivity increases dramatically as the composition of the alloy or solid-solution approaches that of a pure parent materials (i.e., as x = 0 or 1).« less

Phonon scattering mechanisms dictating the thermal conductivity of lead zirconate titanate (PbZr 1- xTi xO 3) thin films across the compositional phase diagram

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

Foley, Brian M.; Paisley, Elizabeth A.; DiAntonio, Christopher

This paper represents a thorough investigation of the thermal conductivity (κ) in both thin film and bulk PbZr 1–xTi xO 3 (PZT) across the compositional phase diagram. Given the technological importance of PZT as a superb piezoelectric and ferroelectric material in devices and systems impacting a wide array of industries, this research serves to fill the gap in knowledge regarding the thermal properties. The thermal conductivities of both thin film and bulk PZT are found to vary by a considerable margin as a function of composition x. Additionally, we observe a discontinuity in κ in the vicinity of the morphotropicmore » phase boundary (MPB, x = 0.48) where there is a 20%–25% decrease in κ in our thin film data, similar to that found in literature data for bulk PZT. The comparison between bulk and thin film materials highlights the sensitivity of κ to size effects such as film thickness and grain size even in disordered alloy/solid-solution materials. A model for the thermal conductivity of PZT as a function of composition (κ(x)) is presented, which enables the application of the virtual crystal approximation for alloy-type material systems with very different crystals structures, resulting in differing temperature trends for κ. We show that in the case of crystalline solid-solutions where the thermal conductivity of one of the parent materials exhibits glass-like temperature trends the compositional dependence of thermal conductivity is relatively constant for most values of x. Finally, this is in stark contrast with the typical trends of thermal conductivity with x in alloys, where the thermal conductivity increases dramatically as the composition of the alloy or solid-solution approaches that of a pure parent materials (i.e., as x = 0 or 1).« less

Strong anisotropic optical conductivity in two-dimensional puckered structures: The role of the Rashba effect

NASA Astrophysics Data System (ADS)

Saberi-Pouya, S.; Vazifehshenas, T.; Salavati-fard, T.; Farmanbar, M.; Peeters, F. M.

2017-08-01

We calculate the optical conductivity of an anisotropic two-dimensional system with Rashba spin-flip excitation within the Kubo formalism. We show that the anisotropic Rashba effect caused by an external field significantly changes the magnitude of the spin splitting. Furthermore, we obtain an analytical expression for the longitudinal optical conductivity associated with interband transitions as a function of the frequency for arbitrary polarization angle. We find that the diagonal components of the optical conductivity tensor are direction dependent and the optical absorption spectrum exhibits a strongly anisotropic absorption window. The height and width of this absorption window are very sensitive to the anisotropy of the system. While the height of absorption peak increases with increasing effective mass anisotropy ratio, the peak intensity is larger when the light polarization is along the armchair direction. Moreover, the absorption peak width becomes broader as the density-of-states mass or Rashba interaction is enhanced. These features in the optical absorption spectrum can be used to determine parameters relevant for spintronics.

The effect of driven electron-phonon coupling on the electronic conductance of a polar nanowire

NASA Astrophysics Data System (ADS)

Mardaani, Mohammad; Rabani, Hassan; Esmaili, Esmat; Shariati, Ashrafalsadat

2015-08-01

A semi-classical model is proposed to explore the effect of electron-phonon coupling on the coherent electronic transport of a polar chain which is confined between two rigid leads in the presence of an external electric field. To this end, we construct the model by means of Green's function technique within the nearest neighbor tight-binding and harmonic approximations. For a time-periodic electric field, the atomic displacements from the equilibrium positions are obtained precisely. The result is then used to compute the electronic transport properties of the chain within the Peierls-type model. The numerical results indicate that the conductance of the system shows interesting behavior in some special frequencies. For each special frequency, there is an electronic quasi-state in which the scattering of electrons by vibrating atoms reaches maximum. The system electronic conductance decreases dramatically at the strong electron-phonon couplings and low electron energies. In the presence of damping forces, the electron-phonon interaction has a less significant effect on the conductance.

Green's function solution to heat transfer of a transparent gas through a tube

NASA Technical Reports Server (NTRS)

Frankel, J. I.

1989-01-01

A heat transfer analysis of a transparent gas flowing through a circular tube of finite thickness is presented. This study includes the effects of wall conduction, internal radiative exchange, and convective heat transfer. The natural mathematical formulation produces a nonlinear, integrodifferential equation governing the wall temperature and an ordinary differential equation describing the gas temperature. This investigation proposes to convert the original system of equations into an equivalent system of integral equations. The Green's function method permits the conversion of an integrodifferential equation into a pure integral equation. The proposed integral formulation and subsequent computational procedure are shown to be stable and accurate.

Toward a systems-level analysis of infection biology: a new method for conducting genetic screens in human cells.

PubMed

Stanley, Sarah A; Hung, Deborah T

2009-12-16

Loss-of-function genetic screens have facilitated great strides in our understanding of the biology of model organisms but have not been possible in diploid human cells. A recent report by Brummelkamp's group in Science describes the use of insertional mutagenesis to generate loss-of-function alleles in a largely haploid human cell line and demonstrates the versatility of this method in screens designed to investigate the host/pathogen interaction. This approach has strengths that are complementary to existing strategies and will facilitate progress toward a systems-level understanding of infectious disease and ultimately the development of new therapeutics.

A DBMS-based medical teleconferencing system.

PubMed

Chun, J; Kim, H; Lee, S; Choi, J; Cho, H

2001-01-01

This article presents the design of a medical teleconferencing system that is integrated with a multimedia patient database and incorporates easy-to-use tools and functions to effectively support collaborative work between physicians in remote locations. The design provides a virtual workspace that allows physicians to collectively view various kinds of patient data. By integrating the teleconferencing function into this workspace, physicians are able to conduct conferences using the same interface and have real-time access to the database during conference sessions. The authors have implemented a prototype based on this design. The prototype uses a high-speed network test bed and a manually created substitute for the integrated patient database.

A DBMS-based Medical Teleconferencing System

PubMed Central

Chun, Jonghoon; Kim, Hanjoon; Lee, Sang-goo; Choi, Jinwook; Cho, Hanik

2001-01-01

This article presents the design of a medical teleconferencing system that is integrated with a multimedia patient database and incorporates easy-to-use tools and functions to effectively support collaborative work between physicians in remote locations. The design provides a virtual workspace that allows physicians to collectively view various kinds of patient data. By integrating the teleconferencing function into this workspace, physicians are able to conduct conferences using the same interface and have real-time access to the database during conference sessions. The authors have implemented a prototype based on this design. The prototype uses a high-speed network test bed and a manually created substitute for the integrated patient database. PMID:11522766

Patient Health Record Systems Scope and Functionalities: Literature Review and Future Directions

PubMed Central

2017-01-01

Background A new generation of user-centric information systems is emerging in health care as patient health record (PHR) systems. These systems create a platform supporting the new vision of health services that empowers patients and enables patient-provider communication, with the goal of improving health outcomes and reducing costs. This evolution has generated new sets of data and capabilities, providing opportunities and challenges at the user, system, and industry levels. Objective The objective of our study was to assess PHR data types and functionalities through a review of the literature to inform the health care informatics community, and to provide recommendations for PHR design, research, and practice. Methods We conducted a review of the literature to assess PHR data types and functionalities. We searched PubMed, Embase, and MEDLINE databases from 1966 to 2015 for studies of PHRs, resulting in 1822 articles, from which we selected a total of 106 articles for a detailed review of PHR data content. Results We present several key findings related to the scope and functionalities in PHR systems. We also present a functional taxonomy and chronological analysis of PHR data types and functionalities, to improve understanding and provide insights for future directions. Functional taxonomy analysis of the extracted data revealed the presence of new PHR data sources such as tracking devices and data types such as time-series data. Chronological data analysis showed an evolution of PHR system functionalities over time, from simple data access to data modification and, more recently, automated assessment, prediction, and recommendation. Conclusions Efforts are needed to improve (1) PHR data quality through patient-centered user interface design and standardized patient-generated data guidelines, (2) data integrity through consolidation of various types and sources, (3) PHR functionality through application of new data analytics methods, and (4) metrics to evaluate clinical outcomes associated with automated PHR system use, and costs associated with PHR data storage and analytics. PMID:29141839

Self-Assembled Polymeric Ionic Liquid-Functionalized Cellulose Nano-crystals: Constructing 3D Ion-conducting Channels Within Ionic Liquid-based Composite Polymer Electrolytes.

PubMed

Shi, Qing Xuan; Xia, Qing; Xiang, Xiao; Ye, Yun Sheng; Peng, Hai Yan; Xue, Zhi Gang; Xie, Xiao Lin; Mai, Yiu-Wing

2017-09-04

Composite polymeric and ionic liquid (IL) electrolytes are some of the most promising electrolyte systems for safer battery technology. Although much effort has been directed towards enhancing the transport properties of polymer electrolytes (PEs) through nanoscopic modification by incorporating nano-fillers, it is still difficult to construct ideal ion conducting networks. Here, a novel class of three-dimensional self-assembled polymeric ionic liquid (PIL)-functionalized cellulose nano-crystals (CNC) confining ILs in surface-grafted PIL polymer chains, able to form colloidal crystal polymer electrolytes (CCPE), is reported. The high-strength CNC nano-fibers, decorated with PIL polymer chains, can spontaneously form three-dimensional interpenetrating nano-network scaffolds capable of supporting electrolytes with continuously connected ion conducting networks with IL being concentrated in conducting domains. These new CCPE have exceptional ionic conductivities, low activation energies (close to bulk IL electrolyte with dissolved Li salt), high Li + transport numbers, low interface resistances and improved interface compatibilities. Furthermore, the CCPE displays good electrochemical properties and a good battery performance. This approach offers a route to leak-free, non-flammable and high ionic conductivity solid-state PE in energy conversion devices. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

About the specialized myocardial conducting tissue.

PubMed

de Micheli Serra, Alfredo; Iturralde Torres, Pedro; Aranda Fraustro, Alberto

2013-01-01

The chronological succession of discoveries on the location and structure of the atrio-ventricular conducting system are described. The starting point of this system is located in the sinus atrial node, identified by the English scientists A. Keith and M. W. Flack in 1907. The atrioventricular conducting system was pointed out by the Swiss physician Wilhelm His Jr. in 1893. The atrioventricular node (AV) was first identified by the Japanese pathologist Sumao Tawara and his German professor Ludwig Aschoff in 1906. Likewise the structure and routes of the three internodal bundles are described. These bundles include: Bachmann's bundle (1916) connecting the right with the left atrium and the AV node; the middle Wenckebach's bundle (1910) and the posterior or Thörel's bundle (1910), extending from the region of the sinus atrial node towards the posterior margin of the AV node. Lastly, the ventricular left and right conduction systems are detailed. These include the main trunk and their peripheral subdivisions with respective networks. Regarding the controversial existence of the left middle subdivision, it can exist in animal and human hearts. Nevertheless, an intermediate left septal network of specialized fibers seems to act as a functional equivalent of this subdivision. Copyright © 2012 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

Fingerprints of transverse and longitudinal coupling between induced open quantum dots in the longitudinal magnetoconductance through antidot lattices

NASA Astrophysics Data System (ADS)

Ujevic, Sebastian; Mendoza, Michel

2010-07-01

We propose numerical simulations of longitudinal magnetoconductance through a finite antidot lattice located inside an open quantum dot with a magnetic field applied perpendicular to the plane. The system is connected to reservoirs using quantum point contacts. We discuss the relationship between the longitudinal magnetoconductance and the generation of transversal couplings between the induced open quantum dots in the system. The system presents longitudinal magnetoconductance maps with crossovers (between transversal bands) and closings (longitudinal decoupling) of fundamental quantum states related to the open quantum dots induced by the antidot lattice. A relationship is observed between the distribution of antidots and the formed conductance bands, allowing a systematic follow up of the bands as a function of the applied magnetic field and quantum point-contact width. We observed a high conductance intensity [between n and (n+1) quantum of conductance, n=1,2,… ] in the regions of crossover and closing of states. This suggests transversal couplings between the induced open quantum dots of the system that can be modulated by varying both the antidots potential and the quantum point-contact width. A new continuous channel (not expected) is induced by the variation in the contact width and generate Fano resonances in the conductance. These resonances can be manipulated by the applied magnetic field.

Nominal Group as Qualifier to "Someone"

ERIC Educational Resources Information Center

Sujatna, Eva Tuckyta Sari; Wahyuni, Sri

2017-01-01

The paper titled "Nominal Group as Qualifier to 'Someone'" investigated types of qualifiers which are embedded to the head "someone" in a nominal group. This research was conducted in the light of Systemic Functional Linguistics analysis. The data was analyzed, classified then described using descriptive qualitative method.…

Anomalous length dependence of conductance of aromatic nanoribbons with amine anchoring groups

NASA Astrophysics Data System (ADS)

Bilić, Ante; Sanvito, Stefano

2012-09-01

Two sets of aromatic nanoribbons, based around a common hexagonal scaffolding, with single and dual terminal amine groups have been considered as potential molecular wires in a junction formed by gold leads. Charge transport through the two-terminal device has been modeled using density functional theory (with and without self-interaction correction) and the nonequilibrium Green's function method. The effects of wire length, multiple terminal contacts, and pathways across the junction have been investigated. For nanoribbons with the oligopyrene motif and conventional single amine terminal groups, an increase in the wire length causes an exponential drop in the conductance. In contrast, for the nanoribbons with the oligoperylene motif and dual amine anchoring groups the predicted conductance rises with the wire length over the whole range of investigated lengths. Only when the effects of self-interaction correction are taken into account, the conductance of the oligoperylene ribbons exhibits saturation for longer members of the series. The oligoperylene nanoribbons, with dual amine groups at both terminals, show the potential to fully harness the highly conjugated system of π molecular orbitals across the junction.

Neural Systems Approaches to Understanding Major Depressive Disorder: An Intrinsic Functional Organization Perspective

PubMed Central

Hamilton, J. Paul; Chen, Michael C.; Gotlib, Ian H.

2012-01-01

Recent research detailing the intrinsic functional organization of the brain provides a unique and useful framework to gain a better understanding of the neural bases of Major Depressive Disorder (MDD). In this review, we first present a brief history of neuroimaging research that has increased our understanding of the functional macro-architecture of the brain. From this macro-architectural perspective, we examine the extant body of functional neuroimaging research assessing MDD with a specific emphasis on the contributions of default-mode, executive, and salience networks in this debilitating disorder. Next, we describe recent investigations conducted in our laboratory in which we explicitly adopt a neural-systems perspective in examining the relations among these networks in MDD. Finally, we offer directions for future research that we believe will facilitate the development of more detailed and integrative models of neural dysfunction in depression. PMID:23477309

Modulation of human sinus node function by systemic hypoxia

NASA Technical Reports Server (NTRS)

Eckberg, D. L.; Bastow, H., III; Scruby, A. E.

1982-01-01

The present study was conducted to determine whether bradycardia develops during systemic hypoxia in supine conscious human volunteers when respiratory frequency and tidal volume are maintained at constant levels. The obtained results suggest that mild hypoxia provokes cardioacceleration in humans, independent of changes of ventilation or baroreflex responsiveness. The earliest cardioacceleration is more prominent in the inspiratory than in the expiratory phase of respiration, and occurs with very small reductions of arterial oxygen saturation. Moderate systemic hypoxia dampens fluctuations of heart rate during the respiratory cycle.

A Summary of NASA Architecture Studies Utilizing Fission Surface Power Technology

NASA Technical Reports Server (NTRS)

Mason, Lee S.; Poston, David I.

2011-01-01

Beginning with the Exploration Systems Architecture Study in 2005, NASA has conducted various mission architecture studies to evaluate implementation options for the U.S. Space Policy. Several of the studies examined the use of Fission Surface Power (FSP) systems for human missions to the lunar and Martian surface. This paper summarizes the FSP concepts developed under four different NASA-sponsored architecture studies: Lunar Architecture Team, Mars Architecture Team, Lunar Surface Systems/Constellation Architecture Team, and International Architecture Working Group-Power Function Team.

The ZOG Technology Demonstration Project: A System Evaluation of USS CARL VINSON (CVN 70)

DTIC Science & Technology

1984-12-01

part of a larger project involving development of a wide range of computer technologies, including artifcial intelligence and a long-range computer...shipboard manage- ment, aircraft management, expert systems, menu selection, man- machine interface, artificial intelligence , automation; shipboard It AWM...functions, planning, evaluation, training, hierarchical data bases The objective of this project was to conduct an evaluation of ZOG, a general purpose

A study of structural properties of gene network graphs for mathematical modeling of integrated mosaic gene networks.

PubMed

Petrovskaya, Olga V; Petrovskiy, Evgeny D; Lavrik, Inna N; Ivanisenko, Vladimir A

2017-04-01

Gene network modeling is one of the widely used approaches in systems biology. It allows for the study of complex genetic systems function, including so-called mosaic gene networks, which consist of functionally interacting subnetworks. We conducted a study of a mosaic gene networks modeling method based on integration of models of gene subnetworks by linear control functionals. An automatic modeling of 10,000 synthetic mosaic gene regulatory networks was carried out using computer experiments on gene knockdowns/knockouts. Structural analysis of graphs of generated mosaic gene regulatory networks has revealed that the most important factor for building accurate integrated mathematical models, among those analyzed in the study, is data on expression of genes corresponding to the vertices with high properties of centrality.

Modelling nanoscale objects in order to conduct an empirical research into their properties as part of an engineering system designed

NASA Astrophysics Data System (ADS)

Makarov, M.; Shchanikov, S.; Trantina, N.

2017-01-01

We have conducted a research into the major, in terms of their future application, properties of nanoscale objects, based on modelling these objects as free-standing physical elements beyond the structure of an engineering system designed for their integration as well as a part of a system that operates under the influence of the external environment. For the empirical research suggested within the scope of this work, we have chosen a nanoscale electronic element intended to be used while designing information processing systems with the parallel architecture - a memristor. The target function of the research was to provide the maximum fault-tolerance index of a memristor-based system when affected by all possible impacts of the internal destabilizing factors and external environment. The research results have enabled us to receive and classify all the factors predetermining the fault-tolerance index of the hardware implementation of a computing system based on the nanoscale electronic element base.

Fourier heat conduction as a strong kinetic effect in one-dimensional hard-core gases

NASA Astrophysics Data System (ADS)

Zhao, Hanqing; Wang, Wen-ge

2018-01-01

For a one-dimensional (1D) momentum conserving system, intensive studies have shown that generally its heat current autocorrelation function (HCAF) tends to decay in a power-law manner and results in the breakdown of the Fourier heat conduction law in the thermodynamic limit. This has been recognized to be a dominant hydrodynamic effect. Here we show that, instead, the kinetic effect can be dominant in some cases and leads to the Fourier law for finite-size systems. Usually the HCAF undergoes a fast decaying kinetic stage followed by a long slowly decaying hydrodynamic tail. In a finite range of the system size, we find that whether the system follows the Fourier law depends on whether the kinetic stage dominates. Our Rapid Communication is illustrated by the 1D hard-core gas models with which the HCAF is derived analytically and verified numerically by molecular dynamics simulations.

A flight test of laminar flow control leading-edge systems

NASA Technical Reports Server (NTRS)

Fischer, M. C.; Wright, A. S., Jr.; Wagner, R. D.

1983-01-01

NASA's program for development of a laminar flow technology base for application to commercial transports has made significant progress since its inception in 1976. Current efforts are focused on development of practical reliable systems for the leading-edge region where the most difficult problems in applying laminar flow exist. Practical solutions to these problems will remove many concerns about the ultimate practicality of laminar flow. To address these issues, two contractors performed studies, conducted development tests, and designed and fabricated fully functional leading-edge test articles for installation on the NASA JetStar aircraft. Systems evaluation and performance testing will be conducted to thoroughly evaluate all system capabilities and characteristics. A simulated airline service flight test program will be performed to obtain the operational sensitivity, maintenance, and reliability data needed to establish that practical solutions exist for the difficult leading-edge area of a future commercial transport employing laminar flow control.

Management of data from clinical trials using the ArchiMed system.

PubMed

Duftschmid, Georg; Gall, Walter; Eigenbauer, Ernst; Dorda, Wolfgang

2002-06-01

Clinical trials constitute a key source of medical research and are therefore conducted on a regular basis at university hospitals. The professional execution of trials requires, among other things, a repertoire of tools that support efficient data management. Tasks that are essential for efficient data management in clinical trials include the following: the design of the trial database, the design of electronic case report forms, recruiting patients, collection of data, and statistical analysis. The present article reports the manner in which these tasks are supported by the ArchiMed system at the University of Vienna and Graz Medical Schools. ArchiMed is customized for clinical end users, allowing them to autonomously manage their clinical trials without having to consult computer experts. An evaluation of the ArchiMed system in 12 trials recently conducted at the University of Vienna Medical School shows that the individual system functions can be usefully applied for data management in clinical trials.

Microscale Symmetrical Electroporator Array as a Versatile Molecular Delivery System

NASA Astrophysics Data System (ADS)

Ouyang, Mengxing; Hill, Winfield; Lee, Jung Hyun; Hur, Soojung Claire

2017-03-01

Successful developments of new therapeutic strategies often rely on the ability to deliver exogenous molecules into cytosol. We have developed a versatile on-chip vortex-assisted electroporation system, engineered to conduct sequential intracellular delivery of multiple molecules into various cell types at low voltage in a dosage-controlled manner. Micro-patterned planar electrodes permit substantial reduction in operational voltages and seamless integration with an existing microfluidic technology. Equipped with real-time process visualization functionality, the system enables on-chip optimization of electroporation parameters for cells with varying properties. Moreover, the system’s dosage control and multi-molecular delivery capabilities facilitate intracellular delivery of various molecules as a single agent or in combination and its utility in biological research has been demonstrated by conducting RNA interference assays. We envision the system to be a powerful tool, aiding a wide range of applications, requiring single-cell level co-administrations of multiple molecules with controlled dosages.

Characterizing fiber-reinforced composite structures using AC-impedance spectroscopy (AC-IS)

NASA Astrophysics Data System (ADS)

Woo, Leta Y.

Property enhancement in composites depends largely on the reinforcement. For fiber-reinforced composites, the distribution of fibers is crucial in determining the electrical and mechanical performance. Image analysis methods for characterization can be time-consuming and/or destructive. This work explores the capability of AC-impedance spectroscopy (AC-IS), an electrical measurement technique, to serve as a rapid, non-destructive tool for characterizing composite microstructure. The composite requirements include a filler that is electrically conducting or semi-conducting with higher conductivity than the matrix, and a high-impedance interface or coating between the filler and the matrix. To establish an AC-IS characterization method, cement-matrix composites with steel reinforcement were employed as both a technologically important and a model system to investigate how fibers affect the electrical response. Beginning with spherical particulates and then fibers, composites were examined using composite theory and an "intrinsic conductivity" approach. The intrinsic conductivity approach applies to composites with low volume fractions of fibers (i.e., in the dilute regime) and relates how the composite conductivity varies relative to the matrix as a function of volume fraction. A universal equivalent circuit model was created to understand the AC-IS response of composites based on the geometry and volume fraction of the filler. Deviation from predicted behavior was assessed using a developed f-function, which quantifies how fibers contribute to the overall electrical response of the composite. Using the f-function, an AC-IS method for investigating fiber dispersion was established to characterize alignment, settling/segregation, and aggregation. Alignment was investigated using measurements made in three directions. A point-probe technique characterized settling and/or large-scale inhomogeneous mixing in samples. Aggregation was quantified using a "dispersion factor" that compared theoretical with measured values and served as an upper limit for how well the fibers were dispersed. The AC-IS method was then extended to two different cement-matrix composite systems, low resistivity fresh-paste cement composites (confirmed by time domain reflectometry) and high resistivity cement composites, both of which required additional analysis to apply the AC-IS characterization method.

Chronic hypertension increases aortic endothelial hydraulic conductivity by upregulating endothelial aquaporin-1 expression.

PubMed

Toussaint, Jimmy; Raval, Chirag Bharavi; Nguyen, Tieuvi; Fadaifard, Hadi; Joshi, Shripad; Wolberg, George; Quarfordt, Steven; Jan, Kung-Ming; Rumschitzki, David S

2017-11-01

Numerous studies have examined the role of aquaporins in osmotic water transport in various systems, but virtually none have focused on the role of aquaporin in hydrostatically driven water transport involving mammalian cells save for our laboratory's recent study of aortic endothelial cells. Here, we investigated aquaporin-1 expression and function in the aortic endothelium in two high-renin rat models of hypertension, the spontaneously hypertensive genetically altered Wistar-Kyoto rat variant and Sprague-Dawley rats made hypertensive by two-kidney, one-clip Goldblatt surgery. We measured aquaporin-1 expression in aortic endothelial cells from whole rat aortas by quantitative immunohistochemistry and function by measuring the pressure-driven hydraulic conductivities of excised rat aortas with both intact and denuded endothelia on the same vessel. We used them to calculate the effective intimal hydraulic conductivity, which is a combination of endothelial and subendothelial components. We observed well-correlated enhancements in aquaporin-1 expression and function in both hypertensive rat models as well as in aortas from normotensive rats whose expression was upregulated by 2 h of forskolin treatment. Upregulated aquaporin-1 expression and function may be a response to hypertension that critically determines conduit artery vessel wall viability and long-term susceptibility to atherosclerosis. NEW & NOTEWORTHY The aortic endothelia of two high-renin hypertensive rat models express greater than two times the aquaporin-1 and, at low pressures, have greater than two times the endothelial hydraulic conductivity of normotensive rats. Data are consistent with theory predicting that higher endothelial aquaporin-1 expression raises the critical pressure for subendothelial intima compression and for artery wall hydraulic conductivity to drop. Copyright © 2017 the American Physiological Society.

A minimum cost tolerance allocation method for rocket engines and robust rocket engine design

NASA Technical Reports Server (NTRS)

Gerth, Richard J.

1993-01-01

Rocket engine design follows three phases: systems design, parameter design, and tolerance design. Systems design and parameter design are most effectively conducted in a concurrent engineering (CE) environment that utilize methods such as Quality Function Deployment and Taguchi methods. However, tolerance allocation remains an art driven by experience, handbooks, and rules of thumb. It was desirable to develop and optimization approach to tolerancing. The case study engine was the STME gas generator cycle. The design of the major components had been completed and the functional relationship between the component tolerances and system performance had been computed using the Generic Power Balance model. The system performance nominals (thrust, MR, and Isp) and tolerances were already specified, as were an initial set of component tolerances. However, the question was whether there existed an optimal combination of tolerances that would result in the minimum cost without any degradation in system performance.

Critical interactions between the Global Fund-supported HIV programs and the health system in Ghana.

PubMed

Atun, Rifat; Pothapregada, Sai Kumar; Kwansah, Janet; Degbotse, D; Lazarus, Jeffrey V

2011-08-01

The support of global health initiatives in recipient countries has been vigorously debated. Critics are concerned that disease-specific programs may be creating vertical and parallel service delivery structures that to some extent undermine health systems. This case study of Ghana aimed to explore how the Global Fund-supported HIV program interacts with the health system there and to map the extent and nature of integration of the national disease program across 6 key health systems functions. Qualitative interviews of national stakeholders were conducted to understand the perceptions of the strengths and weaknesses of the relationship between Global Fund-supported activities and the health system and to identify positive synergies and unintended consequences of integration. Ghana has a well-functioning sector-wide approach to financing its health system, with a strong emphasis on integrated care delivery. Ghana has benefited from US $175 million of approved Global Fund support to address the HIV epidemic, accounting for almost 85% of the National AIDS Control Program budget. Investments in infrastructure, human resources, and commodities have enabled HIV interventions to increase exponentially. Global Fund-supported activities have been well integrated into key health system functions to strengthen them, especially financing, planning, service delivery, and demand generation. Yet, with governance and monitoring and evaluation functions, parallel structures to national systems have emerged, leading to inefficiencies. This case study demonstrates that interactions and integration are highly varied across different health system functions, and strong government leadership has facilitated the integration of Global Fund-supported activities within national programs.

Model identification of stomatognathic muscle system activity during mastication

PubMed Central

Kijak, Edward; Margielewicz, Jerzy; Lietz-Kijak, Danuta; Wilemska-Kucharzewska, Katarzyna; Kucharzewski, Marek; Śliwiński, Zbigniew

2017-01-01

The present study aimed to determine the numeric projection of the function of the mandible and muscle system during mastication. An experimental study was conducted on a healthy 47 year-old subject. On clinical examination no functional disorders were observed. To evaluate the activity of mastication during muscle functioning, bread cubes and hazelnuts were selected (2 cm2 and 1.2/1.3 cm in diameter, respectively) for condyloid processing. An assessment of the activity of mastication during muscle functioning was determined on the basis of numeric calculations conducted with a novel software programme, Kinematics 3D, designed specifically for this study. The efficacy of the model was verified by ensuring the experimentally recorded trajectories were concordant with those calculated numerically. Experimental measurements of the characteristic points of the mandible trajectory were recorded six times. Using the configuration coordinates that were calculated, the dominant componential harmonics of the amplitude-frequency spectrum were identified. The average value of the dominant frequency during mastication of the bread cubes was ~1.16±0.06 Hz, whereas in the case of the hazelnut, this value was nearly two-fold higher at 1.84±0.07 Hz. The most asymmetrical action during mastication was demonstrated to be carried out by the lateral pterygoid muscles, provided that their functioning was not influenced by food consistency. The consistency of the food products had a decisive impact on the frequency of mastication and the number of cycles necessary to grind the food. Model tests on the function of the masticatory organ serve as effective tools since they provide qualitative and quantitative novel information on the functioning of the human masticatory organ. PMID:28123482

The thermal conductivity of mixed fuel U xPu 1-xO 2: molecular dynamics simulations

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

Liu, Xiang-Yang; Cooper, Michael William Donald; Stanek, Christopher Richard

2015-10-16

Mixed oxides (MOX), in the context of nuclear fuels, are a mixture of the oxides of heavy actinide elements such as uranium, plutonium and thorium. The interest in the UO 2-PuO 2 system arises from the fact that these oxides are used both in fast breeder reactors (FBRs) as well as in pressurized water reactors (PWRs). The thermal conductivity of UO 2 fuel is an important material property that affects fuel performance since it is the key parameter determining the temperature distribution in the fuel, thus governing, e.g., dimensional changes due to thermal expansion, fission gas release rates, etc. Formore » this reason it is important to understand the thermal conductivity of MOX fuel and how it differs from UO 2. Here, molecular dynamics (MD) simulations are carried out to determine quantitatively, the effect of mixing on the thermal conductivity of U xPu 1-xO 2, as a function of PuO 2 concentrations, for a range of temperatures, 300 – 1500 K. The results will be used to develop enhanced continuum thermal conductivity models for MARMOT and BISON by INL. These models express the thermal conductivity as a function of microstructure state-variables, thus enabling thermal conductivity models with closer connection to the physical state of the fuel.« less

Intense conductivity suppression by edge defects in zigzag MoS2 and WSe2 nanoribbons: a density functional based tight-binding study.

PubMed

Silva, F W N; Costa, A L M T; Liu, Lei; Barros, E B

2016-11-04

The effects of edge vacancies on the electron transport properties of zigzag MoS2/WSe2 nanoribbons are studied using a density functional theory (DFT)-based tight-binding model with a sp(3)d(5) basis set for the electronic structure calculation and applying the Landauer-Büttiker approach for the electronic transport. Our results show that the presence of a single edge vacancy, with a missing MoS2/WSe2 triplet, is enough to suppress the conductance of the system by almost one half for most energies around the Fermi level. Furthermore, the presence of other single defects along the same edge has little effect on the overall conductance, indicating that the conductance of that particular edge has been strongly suppressed by the first defect. The presence of another defect on the opposite edge further suppresses the quantum conductance, independently of the relative position between the two defects in opposite edges. The introduction of other defects cause the suppression to be energy dependent, leading to conductance peaks which depend on the geometry of the edges. The strong conductance dependence on the presence of edge defects is corroborated by DFT calculations using SIESTA, which show that the electronic bands near the Fermi energy are strongly localized at the edge.

Gear Mesh Loss-of-Lubrication Experiments and Analytical Simulation

NASA Technical Reports Server (NTRS)

Handschuh, Robert F.; Polly, Joseph; Morales, Wilfredo

2011-01-01

An experimental program to determine the loss-of-lubrication (LOL) characteristics of spur gears in an aerospace simulation test facility has been completed. Tests were conducted using two different emergency lubricant types: (1) an oil mist system (two different misted lubricants) and (2) a grease injection system (two different grease types). Tests were conducted using a NASA Glenn test facility normally used for conducting contact fatigue. Tests were run at rotational speeds up to 10000 rpm using two different gear designs and two different gear materials. For the tests conducted using an air-oil misting system, a minimum lubricant injection rate was determined to permit the gear mesh to operate without failure for at least 1 hr. The tests allowed an elevated steady state temperature to be established. A basic 2-D heat transfer simulation has been developed to investigate temperatures of a simulated gear as a function of frictional behavior. The friction (heat generation source) between the meshing surfaces is related to the position in the meshing cycle, the load applied, and the amount of lubricant in the contact. Experimental conditions will be compared to those from the 2-D simulation.

Repulsion-based model for contact angle saturation in electrowetting

PubMed Central

2015-01-01

We introduce a new model for contact angle saturation phenomenon in electrowetting on dielectric systems. This new model attributes contact angle saturation to repulsion between trapped charges on the cap and base surfaces of the droplet in the vicinity of the three-phase contact line, which prevents these surfaces from converging during contact angle reduction. This repulsion-based saturation is similar to repulsion between charges accumulated on the surfaces of conducting droplets which causes the well known Coulombic fission and Taylor cone formation phenomena. In our model, both the droplet and dielectric coating were treated as lossy dielectric media (i.e., having finite electrical conductivities and permittivities) contrary to the more common assumption of a perfectly conducting droplet and perfectly insulating dielectric. We used theoretical analysis and numerical simulations to find actual charge distribution on droplet surface, calculate repulsion energy, and minimize energy of the total system as a function of droplet contact angle. Resulting saturation curves were in good agreement with previously reported experimental results. We used this proposed model to predict effect of changing liquid properties, such as electrical conductivity, and system parameters, such as thickness of the dielectric layer, on the saturation angle, which also matched experimental results. PMID:25759748

Repulsion-based model for contact angle saturation in electrowetting.

PubMed

Ali, Hassan Abdelmoumen Abdellah; Mohamed, Hany Ahmed; Abdelgawad, Mohamed

2015-01-01

We introduce a new model for contact angle saturation phenomenon in electrowetting on dielectric systems. This new model attributes contact angle saturation to repulsion between trapped charges on the cap and base surfaces of the droplet in the vicinity of the three-phase contact line, which prevents these surfaces from converging during contact angle reduction. This repulsion-based saturation is similar to repulsion between charges accumulated on the surfaces of conducting droplets which causes the well known Coulombic fission and Taylor cone formation phenomena. In our model, both the droplet and dielectric coating were treated as lossy dielectric media (i.e., having finite electrical conductivities and permittivities) contrary to the more common assumption of a perfectly conducting droplet and perfectly insulating dielectric. We used theoretical analysis and numerical simulations to find actual charge distribution on droplet surface, calculate repulsion energy, and minimize energy of the total system as a function of droplet contact angle. Resulting saturation curves were in good agreement with previously reported experimental results. We used this proposed model to predict effect of changing liquid properties, such as electrical conductivity, and system parameters, such as thickness of the dielectric layer, on the saturation angle, which also matched experimental results.

Graded Positive Feedback in Elasmobranch Ampullae of Lorenzini

NASA Astrophysics Data System (ADS)

Kalmijn, Ad. J.

2003-05-01

The acute electrical sensitivity of marine sharks and rays is the greatest known in the Animal Kingdom. I investigate the possibility that the underlying biophysical principles are the very same as those encountered in the central nervous system of animal and man. The elasmobranch ampullae of Lorenzini detect the weak electric fields originating from the oceanic environment, whereas the nerve cells of the brain detect the electric fields arising, well, from the central nervous system. In responding to electrical signals, the cell membranes of excitable cells behave in different regions of the cell as negative or positive conductors. The negative and positive conductances in series, loaded by the cell's electrolytic environment, constitute a positive feedback circuit. The result may be of an all-or-none nature, as in peripheral nerve conduction, or of a graded nature, as in central processing. In this respect, the operation of the elasmobranch ampullae of Lorenzini is more akin to the graded, integrative processes of higher brain centers than to the conduction of nerve action potentials. Hence, the positive-feedback ampullary circuit promises to help elucidate the functioning of the central nervous system as profoundly as the squid giant axon has served to reveal the process of nervous conduction.

Transport properties of lithium- lead-vanadium-telluride glass and glass ceramics

NASA Astrophysics Data System (ADS)

Sathish, M.; Eraiah, B.

2014-04-01

Glasses with the chemical composition 35Li2O-(45-x)V2O5-20PbO-xTeO2 (where x = 2.5, 5, 7.5, 10, 15 mol %) have prepared by conventional melt quenching method. The electrical conductivity of Li+ ion conducting lead vanadium telluride glass samples has been carried out both as a function of temperature and frequency in the temperature range 503K-563K and over frequencies 40 Hz to 10 MHz. The electronic conduction has been observed in the present systems. When these samples annealed around 400°C for 2hour become the glass ceramic, which also shows increase tendency of conductivity. SEM confines glass and glass ceramic nature of the prepared samples.

Results from the Operational Testing of the Eaton Smart Grid Capable Electric Vehicle Supply Equipment

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

Bennett, Brion

2014-10-01

The Idaho National Laboratory conducted testing and analysis of the Eaton smart grid capable electric vehicle supply equipment (EVSE), which was a deliverable from Eaton for the U.S. Department of Energy FOA-554. The Idaho National Laboratory has extensive knowledge and experience in testing advanced conductive and wireless charging systems though INL’s support of the U.S. Department of Energy’s Advanced Vehicle Testing Activity. This document details the findings from the EVSE operational testing conducted at the Idaho National Laboratory on the Eaton smart grid capable EVSE. The testing conducted on the EVSE included energy efficiency testing, SAE J1772 functionality testing, abnormalmore » conditions testing, and charging of a plug-in vehicle.« less

Results from Operational Testing of the Siemens Smart Grid-Capable Electric Vehicle Supply Equipment

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

Bennett, Brion

2015-05-01

The Idaho National Laboratory conducted testing and analysis of the Siemens smart grid capable electric vehicle supply equipment (EVSE), which was a deliverable from Siemens for the U.S. Department of Energy FOA-554. The Idaho National Laboratory has extensive knowledge and experience in testing advanced conductive and wireless charging systems though INL’s support of the U.S. Department of Energy’s Advanced Vehicle Testing Activity. This document details the findings from the EVSE operational testing conducted at the Idaho National Laboratory on the Siemens smart grid capable EVSE. The testing conducted on the EVSE included energy efficiency testing, SAE J1772 functionality testing, abnormalmore » conditions testing, and charging of a plug-in vehicle.« less

Key Tasks of Science in Improving Effectiveness of Hard Coal Production in Poland

NASA Astrophysics Data System (ADS)

Dubiński, Józef; Prusek, Stanisław; Turek, Marian

2017-09-01

The article presents an array of specific issues regarding the employed technology and operational efficiency of mining activities, which could and should become the subject of conducted scientific research. Given the circumstances of strong market competition and increasing requirements concerning environmental conditions, both in terms of conducted mining activities and produced coal quality parameters, it is imperative to develop and implement innovative solutions regarding the employed production technology, the safety of work conducted under the conditions of increasing natural hazards, as well as the mining enterprise management systems that enable its effective functioning. The article content pertains to the last group of issues in the most detailed way, particularly in terms of the possibility for rational conducted operation cost reduction.

Polyvagal Theory and Developmental Psychopathology: Emotion Dysregulation and Conduct Problems from Preschool to Adolescence

PubMed Central

Beauchaine, Theodore P.; Gatzke-Kopp, Lisa; Mead, Hilary K.

2007-01-01

In science, theories lend coherence to vast amounts of descriptive information. However, current diagnostic approaches in psychopathology are primarily atheoretical, emphasizing description over etiological mechanisms. We describe the importance of Polyvagal Theory toward understanding the etiology of emotion dysregulation, a hallmark of psychopathology. When combined with theories of social reinforcement and motivation, Polyvagal Theory specifies etiological mechanisms through which distinct patterns of psychopathology emerge. In this paper, we summarize three studies evaluating autonomic nervous system functioning in children with conduct problems, ages 4-18. At all age ranges, these children exhibit attenuated sympathetic nervous system responses to reward, suggesting deficiencies in approach motivation. By middle school, this reward insensitivity is met with inadequate vagal modulation of cardiac output, suggesting additional deficiencies in emotion regulation. We propose a biosocial developmental model of conduct problems in which inherited impulsivity is amplified through social reinforcement of emotional lability. Implications for early intervention are discussed. PMID:17045726

Polyvagal Theory and developmental psychopathology: emotion dysregulation and conduct problems from preschool to adolescence.

PubMed

Beauchaine, Theodore P; Gatzke-Kopp, Lisa; Mead, Hilary K

2007-02-01

In science, theories lend coherence to vast amounts of descriptive information. However, current diagnostic approaches in psychopathology are primarily atheoretical, emphasizing description over etiological mechanisms. We describe the importance of Polyvagal Theory toward understanding the etiology of emotion dysregulation, a hallmark of psychopathology. When combined with theories of social reinforcement and motivation, Polyvagal Theory specifies etiological mechanisms through which distinct patterns of psychopathology emerge. In this paper, we summarize three studies evaluating autonomic nervous system functioning in children with conduct problems, ages 4-18. At all age ranges, these children exhibit attenuated sympathetic nervous system responses to reward, suggesting deficiencies in approach motivation. By middle school, this reward insensitivity is met with inadequate vagal modulation of cardiac output, suggesting additional deficiencies in emotion regulation. We propose a biosocial developmental model of conduct problems in which inherited impulsivity is amplified through social reinforcement of emotional lability. Implications for early intervention are discussed.

Challenges and opportunities of integration of community based Management of Acute Malnutrition into the government health system in Bangladesh: a qualitative study.

PubMed

Ireen, Santhia; Raihan, Mohammad Jyoti; Choudhury, Nuzhat; Islam, M Munirul; Hossain, Md Iqbal; Islam, Ziaul; Rahman, S M Mustafizur; Ahmed, Tahmeed

2018-04-10

Severe acute malnutrition (SAM) in children is the most serious form of malnutrition and is associated with very high rates of morbidity and mortality. For sustainable SAM management, United Nations recommends integration of community based management of acute malnutrition (CMAM) into the health system. The objective of the study was to assess the preparedness of the health system to implement CMAM in Bangladesh. The assessment was undertaken during January to May 2014 by conducting document review, key informant interviews, and direct observation. A total of 38 key informant interviews were conducted among government policy makers and program managers (n = 4), nutrition experts (n = 2), health and nutrition implementing partners (n = 2), development partner (n = 1), government health system staff (n = 5), government front line field workers (n = 22), and community members (n = 2). The assessment was based on: workforce, service delivery, financing, governance, information system, medical supplies, and the broad socio-political context. The government of Bangladesh has developed inpatient and outpatient guidelines for the management of SAM. There are cadres of community health workers of government and non-government actors who can be adequately trained to conduct CMAM. Inpatient management of SAM is available in 288 facilities across the country. However, only 2.7% doctors and 3.3% auxiliary staff are trained on facility based management of SAM. In functional facilities, uninterrupted supply of medicines and therapeutic diet are not available. There is resistance and disagreement among nutrition stakeholders regarding import or local production of ready-to-use therapeutic food (RUTF). Nutrition coordination is fragile and there is no functional supra-ministerial coordination platform for multi-sectoral and multi-stakeholder nutrition. There is an enabling environment for CMAM intervention in Bangladesh although health system strengthening is needed considering the barriers that have been identified. Training of facility based health staff, government community workers, and ensuring uninterrupted supply of medicines and logistics to the functional facilities should be the immediate priorities. Availability of ready-to-use therapeutic food (RUTF) is a critical component of CMAM and government should promote in-country production of RUTF for effective integration of CMAM into the health system in Bangladesh.

Application of low-power, high-rate PCM telemetry in a helicopter instrumentation system

NASA Technical Reports Server (NTRS)

Thomas, Mitchel E.; Diamond, John K.

1987-01-01

The use of low-power, high-rate pulse code modulation (PCM) in a helicopter instrumentation system is examined. A Helicopter Instrumentation and Recording System (HIARS) was developed to obtain main rotor blade measurements and fuselage performance measurements. The HIARS consists of a low-power PCM telemeter, a digital PCM system, an optical rotor position sensor, and a PCM decommutation unit; the components and functions of these subsystems are described. Flight tests were conducted to evaluate the ability of the HIARS to measure aircraft parameters. The test data reveal that the PCM telemetry is applicable to helicopter instrumentation systems.

40 CFR 94.1004 - Maintenance, repair, adjustment, and recordkeeping.

Code of Federal Regulations, 2010 CFR

2010-07-01

... alteration before the emission-control system is restored to proper functioning. The provisions of paragraph... be signed by the executive with responsibility for marine activities of the owner. If the vessel is... executive(s) may authorize a captain or other primary operator to conduct this review and submit the...

Effective Score Reporting of Non-Norm-Referenced Assessment.

ERIC Educational Resources Information Center

Haenn, Joseph F.; And Others

The Maryland State Department of Education issued a request for proposals to develop a score reporting system for the Maryland Functional Testing Program. RMC Research Corporation conducted a literature review of extant literature and developed a national survey of non-norm-referenced test score reporting practices. This comprehensive analysis of…

U.S. Northern Command > About USNORTHCOM > Doing Business with USNORTHCOM

Science.gov Websites

Central Contractor Registration (CCR) http://www.ccr.gov Vendors should register in the U.S. federal government's Central Contractor Registration (CCR). A Data Universal Numbering System (DUNS®) number, provided planning and conducting contracting and contractor management functions in support of joint operations

Beyond Synthesis: Re-Presenting Heterogeneous Research Literature

ERIC Educational Resources Information Center

Sylvester, Allan; Tate, Mary; Johnstone, David

2013-01-01

This article examines the nature, role and function of the literature review in academic discourse. Researchers in information systems (IS) are often advised to espouse a neutral viewpoint and adapt the goal of synthesising previous literature when conducting a literature review. However, since research literature in many areas of IS is diverse…

Polymer-mediated tunneling transport between carbon nanotubes in nanocomposites.

PubMed

Derosa, Pedro A; Michalak, Tyler

2014-05-01

Electron transport in nanocomposites has attracted a good deal of attention for some time now; furthermore, the ability to control its characteristics is a necessary step in the design of multifunctional materials. When conductive nanostructures (for example carbon nanotubes) are inserted in a non-conductive matrix, electron transport below the percolation threshold is dominated by tunneling and thus the conductive characteristics of the composite depends heavily on the characteristics of the tunneling currents between nanoinserts. A parameter-free approach to study tunneling transport between carbon nanotubes across a polymer matrix is presented. The calculation is done with a combination of Density Functional Theory and Green functions (an approach heavily used in molecular electronics) which is shown here to be effective in this non-resonant transport condition. The results show that the method can effectively capture the effect of a dielectric layer in tunneling transport. The current is found to exponentially decrease with the size of the gap for both vacuum and polymer, and that the polymer layer lowers the tunneling barrier enhancing tunneling conduction. For a polyacrylonitrile matrix, a four-fold decrease in the tunneling constant, compared to tunneling in vacuum, is observed, a result that is consistent with available information. The method is very versatile as any DFT functional (or any other quantum mechanics method) can be used and thus the most accurate method for each particular system can be chosen. Furthermore as more methods become available, the calculations can be revised and improved. This approach can be used to design functional materials for fine-tunning the tunneling transport, for instance, the effect of modifying the nanoinsert-matrix interface (for example, by adding functional groups to carbon nanotubes) can be captured and the comparative performance of each interface predicted by simulation.

Experimental and theoretical analysis of nanofluids based on high temperature-heat transfer fluid with enhanced thermal properties

NASA Astrophysics Data System (ADS)

Navas, Javier; Sánchez-Coronilla, Antonio; Martín, Elisa I.; Gómez-Villarejo, Roberto; Teruel, Miriam; Gallardo, Juan Jesús; Aguilar, Teresa; Alcántara, Rodrigo; Fernández-Lorenzo, Concha; Martín-Calleja, Joaquín

2017-04-01

In this work, nanofluids were prepared using commercial Cu nanoparticles and a commercial high temperature-heat transfer Fluid (eutectic mixture of diphenyl oxide and biphenyl) as the base fluid, which is used in concentrating solar power (CSP) plants. Different properties such as density, viscosity, heat capacity and thermal conductivity were characterized. Nanofluids showed enhanced heat transfer efficiency. In detail, the incorporation of Cu nanoparticles led to an increase of the heat capacity up to 14%. Also, thermal conductivity was increased up to 13%. Finally, the performance of the nanofluids prepared increased up to 11% according to the Dittus-Boelter correlation. On the other hand, equilibrium molecular dynamics simulation was used to model the experimental nanofluid system studied. Thermodynamic properties such as heat capacity and thermal conductivity were calculated and the results were compared with experimental data. The analysis of the radial function distributions (RDFs) and the inspection of the spatial distribution functions (SDFs) indicate the important role that plays the metal-oxygen interaction in the system. Dynamic properties such as the diffusion coefficients of base fluid and nanofluid were computed according to Einstein relation by computing the mean square displacement (MSD). Supplementary online material is available in electronic form at http://www.epjap.org

Volcanic geothermal system in the Main Ethiopian Rift: insights from 3D MT finite-element inversion and other exploration methods

NASA Astrophysics Data System (ADS)

Samrock, F.; Grayver, A.; Eysteinsson, H.; Saar, M. O.

2017-12-01

In search for geothermal resources, especially in exploration for high-enthalpy systems found in regions with active volcanism, the magnetotelluric (MT) method has proven to be an efficient tool. Electrical conductivity of the subsurface, imaged by MT, is used for detecting layers of electrically highly conductive clays which form around the surrounding strata of hot circulating fluids and for delineating magmatic heat sources such as zones with partial melting. We present a case study using a novel 3-D inverse solver, based on adaptive local mesh refinement techniques, applied to decoupled forward and inverse mesh parameterizations. The flexible meshing allows accurate representation of surface topography, while keeping computational costs at a reasonable level. The MT data set we analyze was measured at 112 sites, covering an area of 18 by 11 km at a geothermal prospect in the Main Ethiopian Rift. For inverse modelling, we tested a series of different settings to ensure that the recovered structures are supported by the data. Specifically, we tested different starting models, regularization functionals, sets of transfer functions, with and without inclusion of topography. Several robust subsurface structures were revealed. These are prominent features of a high-enthalpy geothermal system: A highly conductive shallow clay cap occurs in an area with high fumarolic activity, and is underlain by a more resistive zone, which is commonly interpreted as a propylitic reservoir and is the main geothermal target for drilling. An interesting discovery is the existence of a channel-like conductor connecting the geothermal field at the surface with an off-rift conductive zone, whose existence was proposed earlier as being related to an off-rift volcanic belt along the western shoulder of the Main Ethiopian Rift. The electrical conductivity model is interpreted together with results from other geoscientific studies and outcomes from satellite remote sensing techniques.

The Electronic Thermal Conductivity of Graphene.

PubMed

Kim, Tae Yun; Park, Cheol-Hwan; Marzari, Nicola

2016-04-13

Graphene, as a semimetal with the largest known thermal conductivity, is an ideal system to study the interplay between electronic and lattice contributions to thermal transport. While the total electrical and thermal conductivity have been extensively investigated, a detailed first-principles study of its electronic thermal conductivity is still missing. Here, we first characterize the electron-phonon intrinsic contribution to the electronic thermal resistivity of graphene as a function of doping using electronic and phonon dispersions and electron-phonon couplings calculated from first-principles at the level of density-functional theory and many-body perturbation theory (GW). Then, we include extrinsic electron-impurity scattering using low-temperature experimental estimates. Under these conditions, we find that the in-plane electronic thermal conductivity κe of doped graphene is ∼300 W/mK at room temperature, independently of doping. This result is much larger than expected and comparable to the total thermal conductivity of typical metals, contributing ∼10% to the total thermal conductivity of bulk graphene. Notably, in samples whose physical or domain sizes are of the order of few micrometers or smaller, the relative contribution coming from the electronic thermal conductivity is more important than in the bulk limit, because lattice thermal conductivity is much more sensitive to sample or grain size at these scales. Last, when electron-impurity scattering effects are included we find that the electronic thermal conductivity is reduced by 30 to 70%. We also find that the Wiedemann-Franz law is broadly satisfied at low and high temperatures but with the largest deviations of 20-50% around room temperature.

Progressive alterations of central nervous system structure and function are caused by charged particle radiation

NASA Astrophysics Data System (ADS)

Nelson, G. A.; Cns Nscor Team

A new NASA-sponsored program project (NSCOR) has been organized to conduct the first comprehensive investigation of the response of a mammalian brain structure (mouse hippocampus) to charged-particle radiation. The NSCOR collaboration has three main goals. The first goal is to quantify the time- and dose-dependent changes in cellular composition and architecture. By using stereology on preserved brains, subsets of cells (neurons, glia, endothelia and stem cells) will be quantified out to 2 years after irradiation with accelerated protons and iron ions. To further characterize changes in vasculature architecture a polymer infusion technique will be used to produce a three-dimensional vasculature cast that then will be mapped by x-ray tomography to determine topological changes, and microscopic infarcts associated with amyloid protein deposits. The 2nd goal is to quantify hippocampal function(s). The primary measurement of function will be extracellular electrical recordings from hippocampal ``brain slices'' that reflect underlying functions such as connectivity, action potential generation & conduction, and neurotransmitter formation, secretion, and uptake. Individual nerve membrane properties will be assessed by ``patch clamp'' recordings. Two non-invasive methods will evaluate brain function and the evolution of changes with time. Electroencephalograms will map macroscopic spontaneous electrical activity while two state-of-the-art MRI magnetization sequences will visualize and quantify local oxygen utilization and white matter fiber tracts structural integrity. To quantify the brains' overall performance under stress, animals will receive a systemic shock mediated by the immune system in the form of a reaction to lipopolysaccharide. A second strategy will employ the APP23 transgenic mouse that develops the pathological changes associated with Alzheimer's disease. Measurements of irradiated mice will determine whether radiation exposure affects the latency and severity of the disease-associated pathological changes. The third goal is to quantify molecular markers that underly cellular and system changes. The team will quantify the frequency and structural spectrum of mutations in hippocampal samples using the E. coli β -galactosidase gene present in a transgenic mouse's tissues. Finally, by using transcription profiling hybridization, the status of a set of 96 genes involved in cytokine signaling during inflammation will be assessed.

Robust Functionalization of Large Microelectrode Arrays by Using Pulsed Potentiostatic Deposition

PubMed Central

Rothe, Joerg; Frey, Olivier; Madangopal, Rajtarun; Rickus, Jenna; Hierlemann, Andreas

2016-01-01

Surface modification of microelectrodes is a central step in the development of microsensors and microsensor arrays. Here, we present an electrodeposition scheme based on voltage pulses. Key features of this method are uniformity in the deposited electrode coatings, flexibility in the overall deposition area, i.e., the sizes and number of the electrodes to be coated, and precise control of the surface texture. Deposition and characterization of four different materials are demonstrated, including layers of high-surface-area platinum, gold, conducting polymer poly(ethylenedioxythiophene), also known as PEDOT, and the non-conducting polymer poly(phenylenediamine), also known as PPD. The depositions were conducted using a fully integrated complementary metal-oxide-semiconductor (CMOS) chip with an array of 1024 microelectrodes. The pulsed potentiostatic deposition scheme is particularly suitable for functionalization of individual electrodes or electrode subsets of large integrated microelectrode arrays: the required deposition waveforms are readily available in an integrated system, the same deposition parameters can be used to functionalize the surface of either single electrodes or large arrays of thousands of electrodes, and the deposition method proved to be robust and reproducible for all materials tested. PMID:28025569

Heat Transfer Performance of Functionalized Graphene Nanoplatelet Aqueous Nanofluids

PubMed Central

Agromayor, Roberto; Cabaleiro, David; Pardinas, Angel A.; Vallejo, Javier P.; Fernandez-Seara, Jose; Lugo, Luis

2016-01-01

The low thermal conductivity of fluids used in many industrial applications is one of the primary limitations in the development of more efficient heat transfer systems. A promising solution to this problem is the suspension of nanoparticles with high thermal conductivities in a base fluid. These suspensions, known as nanofluids, have great potential for enhancing heat transfer. The heat transfer enhancement of sulfonic acid-functionalized graphene nanoplatelet water-based nanofluids is addressed in this work. A new experimental setup was designed for this purpose. Convection coefficients, pressure drops, and thermophysical properties of various nanofluids at different concentrations were measured for several operational conditions and the results are compared with those of pure water. Enhancements in thermal conductivity and in convection heat transfer coefficient reach 12% (1 wt %) and 32% (0.5 wt %), respectively. New correlations capable of predicting the Nusselt number and the friction factor of this kind of nanofluid as a function of other dimensionless quantities are developed. In addition, thermal performance factors are obtained from the experimental convection coefficient and pressure drop data in order to assess the convenience of replacing the base fluid with designed nanofluids. PMID:28773578

Computer-assisted identification and volumetric quantification of dynamic contrast enhancement in brain MRI: an interactive system

NASA Astrophysics Data System (ADS)

Wu, Shandong; Avgeropoulos, Nicholas G.; Rippe, David J.

2013-03-01

We present a dedicated segmentation system for tumor identification and volumetric quantification in dynamic contrast brain magnetic resonance (MR) scans. Our goal is to offer a practically useful tool at the end of clinicians in order to boost volumetric tumor assessment. The system is designed to work in an interactive mode such that maximizes the integration of computing capacity and clinical intelligence. We demonstrate the main functions of the system in terms of its functional flow and conduct preliminary validation using a representative pilot dataset. The system is inexpensive, user-friendly, easy to deploy and integrate with picture archiving and communication systems (PACS), and possible to be open-source, which enable it to potentially serve as a useful assistant for radiologists and oncologists. It is anticipated that in the future the system can be integrated into clinical workflow so that become routine available to help clinicians make more objective interpretations of treatment interventions and natural history of disease to best advocate patient needs.

Development status of regenerable solid amine CO2 control systems

NASA Technical Reports Server (NTRS)

Colling, A. K., Jr.; Nalette, T. A.; Cusick, R. J.; Reysa, R. P.

1985-01-01

The development history of solid amine/water desorbed (SAWD) CO2 control systems is reviewed. The design of the preprototype SAWD I CO2 system on the basis of a three-man metabolic load at the 3.8 mm Hg ambient CO2 level, and the functions of the CO2 removal, CO2 storage/delivery, controller, and life test laboratory support packages are described. The development of a full-scale multiple canister SAWD II preprototype system, which is capable of conducting the CO2 removal/concentration function in a closed-loop atmosphere revitalization system during zero-gravity operation, is examined. The operation of the SAWD II system, including the absorption and desorption cycles, is analyzed. A reduction in the thermal mass of the canister and the system's energy transfer technique result in efficient energy use. The polyether foam, nylon felt, nickel foam, spring retained, and metal bellows bed tests performed to determine the design of the zero-gravity canister are studied; metal bellows are selected for the canister's configuration.

Analysing the Stewardship Function in Botswana’s Health System: Reflecting on the Past, Looking to the Future

PubMed Central

Seitio-Kgokgwe, Onalenna; Gauld, Robin DC; Hill, Philip C.; Barnett, Pauline

2016-01-01

Background: In many parts of the world, ongoing deficiencies in health systems compromise the delivery of health interventions. The World Health Organization (WHO) identified four functions that health systems need to perform to achieve their goals: Efforts to strengthen health systems focus on the way these functions are carried out. While a number of studies on health systems functions have been conducted, the stewardship function has received limited attention. In this article, we evaluate the extent to which the Botswana Ministry of Health (MoH) undertook its stewardship role. Methods: We used the WHO Health Systems Performance Assessment Frame (HSPAF) to guide analysis of the stewardship function of the Botswana’s MoH focusing on formulation of national health policies, exerting influence through health regulation, and coalition building. Data were abstracted from published and unpublished documents. We interviewed 54 key informants comprising staff of the MoH (N = 40) and stakeholder organizations (N = 14). Data from documents was analyzed through content analysis. Interviews were transcribed and analyzed through thematic analysis. Results: A lack of capacity for health policy development was identified. Significant policy gaps existed in some areas. Challenges were reported in policy implementation. While the MoH made efforts in developing various statutes that regulated different aspects of the health system, some gaps existed in the regulatory framework. Poor enforcement of legislation was a challenge. Although the MoH had a high number of stakeholders, the mechanisms for stakeholder engagement in the planning processes were weak. Conclusion: Problems in the exercise of the stewardship function posed challenges in ensuring accountability and limited the health system’s ability to benefit from its stakeholders. Ongoing efforts to establish a District Health System under control of the MoH, attempts to improve service delivery at a national level and political will to strengthen public-private engagement mechanisms are some of the prospects that can improve the MoH’s stewardship function. PMID:28005550

An analysis of electrical conductivity model in saturated porous media

NASA Astrophysics Data System (ADS)

Cai, J.; Wei, W.; Qin, X.; Hu, X.

2017-12-01

Electrical conductivity of saturated porous media has numerous applications in many fields. In recent years, the number of theoretical methods to model electrical conductivity of complex porous media has dramatically increased. Nevertheless, the process of modeling the spatial conductivity distributed function continues to present challenges when these models used in reservoirs, particularly in porous media with strongly heterogeneous pore-space distributions. Many experiments show a more complex distribution of electrical conductivity data than the predictions derived from the experiential model. Studies have observed anomalously-high electrical conductivity of some low-porosity (tight) formations compared to more- porous reservoir rocks, which indicates current flow in porous media is complex and difficult to predict. Moreover, the change of electrical conductivity depends not only on the pore volume fraction but also on several geometric properties of the more extensive pore network, including pore interconnection and tortuosity. In our understanding of electrical conductivity models in porous media, we study the applicability of several well-known methods/theories to electrical characteristics of porous rocks as a function of pore volume, tortuosity and interconnection, to estimate electrical conductivity based on the micro-geometrical properties of rocks. We analyze the state of the art of scientific knowledge and practice for modeling porous structural systems, with the purpose of identifying current limitations and defining a blueprint for future modeling advances. We compare conceptual descriptions of electrical current flow processes in pore space considering several distinct modeling approaches. Approaches to obtaining more reasonable electrical conductivity models are discussed. Experiments suggest more complex relationships between electrical conductivity and porosity than experiential models, particularly in low-porosity formations. However, the available theoretical models combined with simulations do provide insight to how microscale physics affects macroscale electrical conductivity in porous media.

Thermodynamics of pairing in mesoscopic systems

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

Sumaryada, Tony; Volya, Alexander

Using numerical and analytical methods implemented for different models, we conduct a systematic study of the thermodynamic properties of pairing correlations in mesoscopic nuclear systems. Various quantities are calculated and analyzed using the exact solution of pairing. An in-depth comparison of canonical, grand canonical, and microcanonical ensembles is conducted. The nature of the pairing phase transition in a small system is of a particular interest. We discuss the onset of discontinuity in the thermodynamic variables, fluctuations, and evolution of zeros of the canonical and grand canonical partition functions in the complex plane. The behavior of the invariant correlational entropy ismore » also studied in the transitional region of interest. The change in the character of the phase transition due to the presence of a magnetic field is discussed along with studies of superconducting thermodynamics.« less

Video requirements for remote medical diagnosis

NASA Technical Reports Server (NTRS)

Davis, J. G.

1974-01-01

Minimal television system requirements for medical telediagnosis were studied. The experiment was conducted with the aid of a simulated telemedicine system. The first step involved making high quality videotape recordings of actual medical examinations conducted by a skilled nurse under the direction of a physician watching on closed circuit television. These recordings formed the baseline for the study. Next, these videotape recordings were electronically degraded to simulate television systems of less than broadcast quality. Finally, the baseline and degraded video recordings were shown (via a statistically randomized procedure) to a large number of physicians who attempted to reach a correct medical diagnosis and to visually recognize key physical signs for each patient. By careful scoring and analysis of the results of these viewings, the pictorial and diagnostic limitations as a function of technical video characteristics were to be defined.

Real time polymer nanocomposites-based physical nanosensors: theory and modeling.

PubMed

Bellucci, Stefano; Shunin, Yuri; Gopeyenko, Victor; Lobanova-Shunina, Tamara; Burlutskaya, Nataly; Zhukovskii, Yuri

2017-09-01

Functionalized carbon nanotubes and graphene nanoribbons nanostructures, serving as the basis for the creation of physical pressure and temperature nanosensors, are considered as tools for ecological monitoring and medical applications. Fragments of nanocarbon inclusions with different morphologies, presenting a disordered system, are regarded as models for nanocomposite materials based on carbon nanoсluster suspension in dielectric polymer environments (e.g., epoxy resins). We have formulated the approach of conductivity calculations for carbon-based polymer nanocomposites using the effective media cluster approach, disordered systems theory and conductivity mechanisms analysis, and obtained the calibration dependences. Providing a proper description of electric responses in nanosensoring systems, we demonstrate the implementation of advanced simulation models suitable for real time control nanosystems. We also consider the prospects and prototypes of the proposed physical nanosensor models providing the comparisons with experimental calibration dependences.

Real time polymer nanocomposites-based physical nanosensors: theory and modeling

NASA Astrophysics Data System (ADS)

Bellucci, Stefano; Shunin, Yuri; Gopeyenko, Victor; Lobanova-Shunina, Tamara; Burlutskaya, Nataly; Zhukovskii, Yuri

2017-09-01

Functionalized carbon nanotubes and graphene nanoribbons nanostructures, serving as the basis for the creation of physical pressure and temperature nanosensors, are considered as tools for ecological monitoring and medical applications. Fragments of nanocarbon inclusions with different morphologies, presenting a disordered system, are regarded as models for nanocomposite materials based on carbon nanoсluster suspension in dielectric polymer environments (e.g., epoxy resins). We have formulated the approach of conductivity calculations for carbon-based polymer nanocomposites using the effective media cluster approach, disordered systems theory and conductivity mechanisms analysis, and obtained the calibration dependences. Providing a proper description of electric responses in nanosensoring systems, we demonstrate the implementation of advanced simulation models suitable for real time control nanosystems. We also consider the prospects and prototypes of the proposed physical nanosensor models providing the comparisons with experimental calibration dependences.

Information technology systems in public sector health facilities in developing countries: the case of South Africa

PubMed Central

2013-01-01

Background The public healthcare sector in developing countries faces many challenges including weak healthcare systems and under-resourced facilities that deliver poor outcomes relative to total healthcare expenditure. Global references demonstrate that information technology has the ability to assist in this regard through the automation of processes, thus reducing the inefficiencies of manually driven processes and lowering transaction costs. This study examines the impact of hospital information systems implementation on service delivery, user adoption and organisational culture within two hospital settings in South Africa. Methods Ninety-four interviews with doctors, nurses and hospital administrators were conducted in two public sector tertiary healthcare facilities (in two provinces) to record end-user perceptions. Structured questionnaires were used to conduct the interviews with both qualitative and quantitative information. Results Noteworthy differences were observed among the three sample groups of doctors, nurses and administrators as well as between our two hospital groups. The impact of automation in terms of cost and strategic value in public sector hospitals is shown to have yielded positive outcomes with regard to patient experience, hospital staff workflow enhancements, and overall morale in the workplace. Conclusion The research provides insight into the reasons for investing in system automation, the associated outcomes, and organisational factors that impact the successful adoption of IT systems. In addition, it finds that sustainable success in these initiatives is as much a function of the technology as it is of the change management function that must accompany the system implementation. PMID:23347433

Information technology systems in public sector health facilities in developing countries: the case of South Africa.

PubMed

Cline, Gregory B; Luiz, John M

2013-01-24

The public healthcare sector in developing countries faces many challenges including weak healthcare systems and under-resourced facilities that deliver poor outcomes relative to total healthcare expenditure. Global references demonstrate that information technology has the ability to assist in this regard through the automation of processes, thus reducing the inefficiencies of manually driven processes and lowering transaction costs. This study examines the impact of hospital information systems implementation on service delivery, user adoption and organisational culture within two hospital settings in South Africa. Ninety-four interviews with doctors, nurses and hospital administrators were conducted in two public sector tertiary healthcare facilities (in two provinces) to record end-user perceptions. Structured questionnaires were used to conduct the interviews with both qualitative and quantitative information. Noteworthy differences were observed among the three sample groups of doctors, nurses and administrators as well as between our two hospital groups. The impact of automation in terms of cost and strategic value in public sector hospitals is shown to have yielded positive outcomes with regard to patient experience, hospital staff workflow enhancements, and overall morale in the workplace. The research provides insight into the reasons for investing in system automation, the associated outcomes, and organisational factors that impact the successful adoption of IT systems. In addition, it finds that sustainable success in these initiatives is as much a function of the technology as it is of the change management function that must accompany the system implementation.

High temperature insulation materials for reradiative thermal protection systems

NASA Technical Reports Server (NTRS)

Hughes, T. A.

1972-01-01

Results are presented of a two year program to evaluate packaged thermal insulations for use under a metallic radiative TPS of a shuttle orbiter vehicle. Evaluations demonstrated their survival for up to 100 mission reuse cycles under shuttle acoustic and thermal loads with peak temperatures of 1000 F, 1800 F, 2000 F, 2200 F and 2500 F. The specimens were composed of low density refractory fiber felts, packaged in thin gage metal foils. In addition, studies were conducted on the venting requirements of the packages, salt spray resistance of the metal foils, and the thermal conductivity of many of the insulations as a function of temperature and ambient air pressure. Data is also presented on the radiant energy transport through insulations, and back-scattering coefficients were experimentally determined as a function of source temperature.

Constitutional rho-kinase regulates atrioventricular nodal conduction and ventricular repolarization of the canine heart.

PubMed

Sugiyama, Atsushi; Takahara, Akira; Yatomi, Yutaka; Satoh, Yoshioki; Nakamura, Yuji; Hashimoto, Keitaro

2003-06-01

Given the limited information, physiological roles of Rho-kinase in the cardiac conduction system and ventricular repolarization process were assessed in comparison with those in the coronary vascular tone. A specific Rho-kinase inhibitor Y-27632 was administered to the nutrient coronary artery of the canine isolated, blood-perfused atrioventricular node preparation under the monitoring of the ventricular monophasic action potentials. Administration of Y-27632 moderately suppressed the atrioventricular nodal conduction, slightly but significantly accelerated the repolarization process, and potently increased the coronary blood flow, whereas it hardly affected the intraventricular conduction. The estimated concentrations of Y-27632 causing the currently observed effects were enough to inhibit Rho-kinase. These results suggest that constitutional Rho-kinase functions to moderately facilitate the atrioventricular nodal conduction, slightly delay ventricular repolarization process, and significantly increase the coronary vascular tone.

Vitamin D metabolism, sex hormones, and male reproductive function.

PubMed

Blomberg Jensen, Martin

2012-08-01

The spectrum of vitamin D (VD)-mediated effects has expanded in recent years, and VD is now recognized as a versatile signaling molecule rather than being solely a regulator of bone health and calcium homeostasis. One of the recently identified target areas of VD is male reproductive function. The VD receptor (VDR) and the VD metabolizing enzyme expression studies documented the presence of this system in the testes, mature spermatozoa, and ejaculatory tract, suggesting that both systemic and local VD metabolism may influence male reproductive function. However, it is still debated which cell is the main VD target in the testis and to what extent VD is important for sex hormone production and function of spermatozoa. This review summarizes descriptive studies on testicular VD metabolism and spatial distribution of VDR and the VD metabolizing enzymes in the mammalian testes and discusses mechanistic and association studies conducted in animals and humans. The reviewed evidence suggests some effects of VD on estrogen and testosterone biosynthesis and implicates involvement of both systemic and local VD metabolism in the regulation of male fertility potential.

Current limiting remote power control module

NASA Technical Reports Server (NTRS)

Hopkins, Douglas C.

1990-01-01

The power source for the Space Station Freedom will be fully utilized nearly all of the time. As such, any loads on the system will need to operate within expected limits. Should any load draw an inordinate amount of power, the bus voltage for the system may sag and disrupt the operation of other loads. To protect the bus and loads some type of power interface between the bus and each load must be provided. This interface is most crucial when load faults occur. A possible system configuration is presented. The proposed interface is the Current Limiting Remote Power Controller (CL-RPC). Such an interface should provide the following power functions: limit overloading and resulting undervoltage; prevent catastrophic failure and still provide for redundancy management within the load; minimize cable heating; and provide accurate current measurement. A functional block diagram of the power processing stage of a CL-RPC is included. There are four functions that drive the circuit design: rate control of current; current sensing; the variable conductance switch (VCS) technology; and the algorithm used for current limiting. Each function is discussed separately.

Existence and energy decay of a nonuniform Timoshenko system with second sound

NASA Astrophysics Data System (ADS)

Hamadouche, Taklit; Messaoudi, Salim A.

2018-02-01

In this paper, we consider a linear thermoelastic Timoshenko system with variable physical parameters, where the heat conduction is given by Cattaneo's law and the coupling is via the displacement equation. We discuss the well-posedness and the regularity of solution using the semigroup theory. Moreover, we establish the exponential decay result provided that the stability function χ r(x)=0. Otherwise, we show that the solution decays polynomially.

Common Aperture Techniques for Imaging Electro-Optical Sensors (CATIES).

DTIC Science & Technology

1980-02-01

milliradians ) at the 5.33:1 zoom point. The zoom optics contain five elements with two moveable air -spaced doublets for accomplishing the zoom function...included in the electrical and optical design but due to funding limitations, system safety requirements during the testing phase and lack of long-term...determined during the system testing phase to be conducted by the Air Force. Limited electronic signal processing (split screen and video mix) was

HOPE information system review

NASA Astrophysics Data System (ADS)

Suzuki, Yoshiaki; Nishiyama, Kenji; Ono, Shuuji; Fukuda, Kouin

1992-08-01

An overview of the review conducted on H-2 Orbiting Plane (HOPE) is presented. A prototype model was constructed by inputting various technical information proposed by related laboratories. Especially operation flow which enables understanding of correlation between various analysis items, judgement criteria, technical data, and interfaces with others was constructed. Technical information data base and retrieval systems were studied. A Macintosh personal computer was selected for information shaping because of its excellent function, performance, operability, and software completeness.

ISSA/TSS power preliminary design

NASA Technical Reports Server (NTRS)

Main, John A.

1996-01-01

A projected power shortfall during the initial utilization flights of the International Space Station Alpha (ISSA) has prompted an inquiry into the use of the Tethered Satellite System (TSS) to provide station power. The preliminary design of the combined ISSA/TSS system is currently underway in the Preliminary Design Office at the Marshall Space Flight Center. This document focuses on the justification for using a tether system on space station, the physical principles behind such a system, and how it might be operated to best utilize its capabilities. The basic components of a simple DC generator are a magnet of some type and a conductive wire. Moving the wire through the magnetic field causes forces to be applied to the electric charges in the conductor, and thus current is induced to flow. This simple concept is the idea behind generating power with space-borne tether systems. The function of the magnet is performed by the earth's magnetic field, and orbiting a conductive tether about the earth effectively moves the tether through the field.

Test and control computer user's guide for a digital beam former test system

NASA Technical Reports Server (NTRS)

Alexovich, Robert E.; Mallasch, Paul G.

1992-01-01

A Digital Beam Former Test System was developed to determine the effects of noise, interferers and distortions, and digital implementations of beam forming as applied to the Tracking and Data Relay Satellite 2 (TDRS 2) architectures. The investigation of digital beam forming with application to TDRS 2 architectures, as described in TDRS 2 advanced concept design studies, was conducted by the NASA/Lewis Research Center for NASA/Goddard Space Flight Center. A Test and Control Computer (TCC) was used as the main controlling element of the digital Beam Former Test System. The Test and Control Computer User's Guide for a Digital Beam Former Test System provides an organized description of the Digital Beam Former Test System commands. It is written for users who wish to conduct tests of the Digital Beam forming Test processor using the TCC. The document describes the function, use, and syntax of the TCC commands available to the user while summarizing and demonstrating the use of the commands wtihin DOS batch files.

The Next Step in Deployment of Computer Based Procedures For Field Workers: Insights And Results From Field Evaluations at Nuclear Power Plants

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

Oxstrand, Johanna; Le Blanc, Katya L.; Bly, Aaron

The paper-based procedures currently used for nearly all activities in the commercial nuclear power industry have a long history of ensuring safe operation of the plants. However, there is potential to greatly increase efficiency and safety by improving how the human operator interacts with the procedures. One way to achieve these improvements is through the use of computer-based procedures (CBPs). A CBP system offers a vast variety of improvements, such as context driven job aids, integrated human performance tools (e.g., placekeeping, correct component verification, etc.), and dynamic step presentation. The latter means that the CBP system could only display relevantmore » steps based on operating mode, plant status, and the task at hand. A dynamic presentation of the procedure (also known as context-sensitive procedures) will guide the operator down the path of relevant steps based on the current conditions. This feature will reduce the operator’s workload and inherently reduce the risk of incorrectly marking a step as not applicable and the risk of incorrectly performing a step that should be marked as not applicable. The research team at the Idaho National Laboratory has developed a prototype CBP system for field workers, which has been evaluated from a human factors and usability perspective in four laboratory studies. Based on the results from each study revisions were made to the CBP system. However, a crucial step to get the end users' (e.g., auxiliary operators, maintenance technicians, etc.) acceptance is to put the system in their hands and let them use it as a part of their everyday work activities. In the spring 2014 the first field evaluation of the INL CBP system was conducted at a nuclear power plant. Auxiliary operators conduct a functional test of one out of three backup air compressors each week. During the field evaluation activity, one auxiliary operator conducted the test with the paper-based procedure while a second auxiliary operator followed along with the computer-based procedure. After each conducted functional test the operators were asked a series of questions designed to provide feedback on the feasibility to use a CBP system in the plant and the general user experience of the CBP system. This paper will describe the field evaluation and its results in detail. For example, the result shows that the context driven job aids and the incorporated human performance tools are much liked by the auxiliary operators. The paper will describe and present initial findings from a second field evaluation conducted at second nuclear utility. For this field evaluation a preventive maintenance work order for the HVAC system was used. In addition, there will be a description of the method and objective of two field evaluations planned to be conducted late 2014 or early 2015.« less

Production of functional human insulin-like growth factor binding proteins (IGFBPs) using recombinant expression in HEK293 cells.

PubMed

Wanscher, Anne Sofie Molsted; Williamson, Michael; Ebersole, Tasja Wainani; Streicher, Werner; Wikström, Mats; Cazzamali, Giuseppe

2015-04-01

Insulin-like growth factor binding proteins (IGFBPs) display many functions in humans including regulation of the insulin-like growth factor (IGF) signaling pathway. The various roles of human IGFBPs make them attractive protein candidates in drug discovery. Structural and functional knowledge on human proteins with therapeutic relevance is needed to design and process the next generation of protein therapeutics. In order to conduct structural and functional investigations large quantities of recombinant proteins are needed. However, finding a suitable recombinant production system for proteins such as full-length human IGFBPs, still remains a challenge. Here we present a mammalian HEK293 expression method suitable for over-expression of secretory full-length human IGFBP-1 to -7. Protein purification of full-length human IGFBP-1, -2, -3 and -5 was conducted using a two-step chromatography procedure and the final protein yields were between 1 and 12mg protein per liter culture media. The recombinant IGFBPs contained PTMs and exhibited high-affinity interactions with their natural ligands IGF-1 and IGF-2. Copyright © 2014 Elsevier Inc. All rights reserved.

Role of insulin signaling impairment, adiponectin and dyslipidemia in peripheral and central neuropathy in mice.

PubMed

Anderson, Nicholas J; King, Matthew R; Delbruck, Lina; Jolivalt, Corinne G

2014-06-01

One of the tissues or organs affected by diabetes is the nervous system, predominantly the peripheral system (peripheral polyneuropathy and/or painful peripheral neuropathy) but also the central system with impaired learning, memory and mental flexibility. The aim of this study was to test the hypothesis that the pre-diabetic or diabetic condition caused by a high-fat diet (HFD) can damage both the peripheral and central nervous systems. Groups of C57BL6 and Swiss Webster mice were fed a diet containing 60% fat for 8 months and compared to control and streptozotocin (STZ)-induced diabetic groups that were fed a standard diet containing 10% fat. Aspects of peripheral nerve function (conduction velocity, thermal sensitivity) and central nervous system function (learning ability, memory) were measured at assorted times during the study. Both strains of mice on HFD developed impaired glucose tolerance, indicative of insulin resistance, but only the C57BL6 mice showed statistically significant hyperglycemia. STZ-diabetic C57BL6 mice developed learning deficits in the Barnes maze after 8 weeks of diabetes, whereas neither C57BL6 nor Swiss Webster mice fed a HFD showed signs of defects at that time point. By 6 months on HFD, Swiss Webster mice developed learning and memory deficits in the Barnes maze test, whereas their peripheral nervous system remained normal. In contrast, C57BL6 mice fed the HFD developed peripheral nerve dysfunction, as indicated by nerve conduction slowing and thermal hyperalgesia, but showed normal learning and memory functions. Our data indicate that STZ-induced diabetes or a HFD can damage both peripheral and central nervous systems, but learning deficits develop more rapidly in insulin-deficient than in insulin-resistant conditions and only in Swiss Webster mice. In addition to insulin impairment, dyslipidemia or adiponectinemia might determine the neuropathy phenotype. © 2014. Published by The Company of Biologists Ltd.

Phylogenetic analysis of proteins associated in the four major energy metabolism systems: photosynthesis, aerobic respiration, denitrification, and sulfur respiration.

PubMed

Tomiki, Takeshi; Saitou, Naruya

2004-08-01

The four electron transfer energy metabolism systems, photosynthesis, aerobic respiration, denitrification, and sulfur respiration, are thought to be evolutionarily related because of the similarity of electron transfer patterns and the existence of some homologous proteins. How these systems have evolved is elusive. We therefore conducted a comprehensive homology search using PSI-BLAST, and phylogenetic analyses were conducted for the three homologous groups (groups 1-3) based on multiple alignments of domains defined in the Pfam database. There are five electron transfer types important for catalytic reaction in group 1, and many proteins bind molybdenum. Deletions of two domains led to loss of the function of binding molybdenum and ferredoxin, and these deletions seem to be critical for the electron transfer pattern changes in group 1. Two types of electron transfer were found in group 2, and all its member proteins bind siroheme and ferredoxin. Insertion of the pyridine nucleotide disulfide oxidoreductase domain seemed to be the critical point for the electron transfer pattern change in this group. The proteins belonging to group 3 are all flavin enzymes, and they bind flavin adenine dinucleotide (FAD) or flavin mononucleotide (FMN). Types of electron transfer in this group are divergent, but there are two common characteristics. NAD(P)H works as an electron donor or acceptor, and FAD or FMN transfers electrons from/to NAD(P)H. Electron transfer functions might be added to these common characteristics by the addition of functional domains through the evolution of group 3 proteins. Based on the phylogenetic analyses in this study and previous studies, we inferred the phylogeny of the energy metabolism systems as follows: photosynthesis (and possibly aerobic respiration) and the sulfur/nitrogen assimilation system first diverged, then the sulfur/nitrogen dissimilation system was produced from the latter system.

Comparison of two data acquisition and processing systems of Moller polarimeter in Hall A of Jefferson Lab

DOE PAGES

Vereshchaka, Vadym V.; Glamazdin, Oleksandr V.; Pomatsalyuk, Roman I.

2014-07-01

Two data acquisition and processing systems are used simultaneously to measure electron beam polarization by Moller polarimeter in Hall A of Jefferson Lab (Newport News, VA, USA). The old system (since 1997) is fully functional, but is not repairable in case of malfunction (system modules arenot manufactured anymore). The new system (since 2010) based on flash-ADC is more accurate, but currently requires more detailed adjustment and further improvement. Description and specifications of two data acquisition and processing systems have been given. The results of polarization measurements during experiments conducted in Hall A from 2010 to 2012 are compared.

Electrodynamic tethers for energy conversion

NASA Technical Reports Server (NTRS)

Nobles, W.

1986-01-01

Conductive tethers have been proposed as a new method for converting orbital mechanical energy into electrical power for use on-board a satellite (generator mode) or conversely (motor mode) as a method of providing electric propulsion using electrical energy from the satellite. The operating characteristics of such systems are functionally dependent on orbit altitude and inclination. Effects of these relationships are examined to determine acceptable regions of application. To identify system design considerations, a specific set of system performance goals and requirements are selected. The case selected is for a 25 kW auxiliary power system for use on Space Station. Appropriate system design considerations are developed, and the resulting system is described.

Experimental investigation of alternative transmission functions: Quantitative evidence for the importance of nonlinear transmission dynamics in host-parasite systems.

PubMed

Orlofske, Sarah A; Flaxman, Samuel M; Joseph, Maxwell B; Fenton, Andy; Melbourne, Brett A; Johnson, Pieter T J

2018-05-01

Understanding pathogen transmission is crucial for predicting and managing disease. Nonetheless, experimental comparisons of alternative functional forms of transmission remain rare, and those experiments that are conducted are often not designed to test the full range of possible forms. To differentiate among 10 candidate transmission functions, we used a novel experimental design in which we independently varied four factors-duration of exposure, numbers of parasites, numbers of hosts and parasite density-in laboratory infection experiments. We used interactions between amphibian hosts and trematode parasites as a model system and all candidate models incorporated parasite depletion. An additional manipulation involving anaesthesia addressed the effects of host behaviour on transmission form. Across all experiments, nonlinear transmission forms involving either a power law or a negative binomial function were the best-fitting models and consistently outperformed the linear density-dependent and density-independent functions. By testing previously published data for two other host-macroparasite systems, we also found support for the same nonlinear transmission forms. Although manipulations of parasite density are common in transmission studies, the comprehensive set of variables tested in our experiments revealed that variation in density alone was least likely to differentiate among competing transmission functions. Across host-pathogen systems, nonlinear functions may often more accurately represent transmission dynamics and thus provide more realistic predictions for infection. © 2017 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

The key actors maintaining elders in functional autonomy in Bobo-Dioulasso (Burkina Faso)

PubMed Central

2014-01-01

Background Globally, a significant increase in functional disability among the elderly is expected in the near future. It is therefore vital to begin considering how Sub-Saharan Africa countries can best start building or strengthening the care and support system for that target population. Study objectives are: 1) identify the key actors of the social system who maintain elders in functional autonomy at home in Bobo-Dioulasso (Burkina Faso) and 2) to describe the functional status of older people living at home. Methods We conducted a longitudinal descriptive study among the elderly aged 60 and above (351). Their functional status was evaluated using the Functional Autonomy Measurement System (SMAF). Data analysis was done using the statistical software package STATA (SE11). Results In Bobo-Dioulasso, 68% of seniors have good functional capacity or a slight incapacity and 32% have moderate to severe incapacities. Older people die before (3%) or during (14%) moderate to severe disabilities. This would mean that the quality of medical and/or social care is not good for maintaining functional autonomy of older people with moderate to severe disabilities. Two main groups of people contribute to maintain elders in functional autonomy: the elderly themselves and their family. Community, private or public structures for maintaining elders in functional autonomy are non-existent. The social system for maintaining elders in functional autonomy is incomplete and failing. In case of functional handicap at home, the elders die. But stakeholders are not conscious of this situation; they believe that this system is good for maintaining elders in functional autonomy. Conclusion It is likely that the absence of formal care and support structure likely shortens the lifespan of severely disabled older people. Stakeholders have not yet looked at this possibility. The stakeholders should seriously think about: 1) how to establish the third level of actors who can fulfill the needs to maintain elders in functional autonomy that are not satisfied by others (family members or the older individuals themselves), and 2) how to reinforce the role of each actor and the collaboration between the different groups of people of this system. PMID:24997509

Better Resolved Low Frequency Dispersions by the Apt Use of Kramers-Kronig Relations, Differential Operators, and All-In-1 Modeling

PubMed Central

van Turnhout, J.

2016-01-01

The dielectric spectra of colloidal systems often contain a typical low frequency dispersion, which usually remains unnoticed, because of the presence of strong conduction losses. The KK relations offer a means for converting ε′ into ε″ data. This allows us to calculate conduction free ε″ spectra in which the l.f. dispersion will show up undisturbed. This interconversion can be done on line with a moving frame of logarithmically spaced ε′ data. The coefficients of the conversion frames were obtained by kernel matching and by using symbolic differential operators. Logarithmic derivatives and differences of ε′ and ε″ provide another option for conduction free data analysis. These difference-based functions actually derived from approximations to the distribution function, have the additional advantage of improving the resolution power of dielectric studies. A high resolution is important because of the rich relaxation structure of colloidal suspensions. The development of all-in-1 modeling facilitates the conduction free and high resolution data analysis. This mathematical tool allows the apart-together fitting of multiple data and multiple model functions. It proved also useful to go around the KK conversion altogether. This was achieved by the combined approximating ε′ and ε″ data with a complex rational fractional power function. The all-in-1 minimization turned out to be also highly useful for the dielectric modeling of a suspension with the complex dipolar coefficient. It guarantees a secure correction for the electrode polarization, so that the modeling with the help of the differences ε′ and ε″ can zoom in on the genuine colloidal relaxations. PMID:27242997

Determination of hydraulic conductivity in three dimensions and its relation to dispersivity: Chapter D in Ground-water contamination by crude oil at the Bemidji, Minnesota, research site; US Geological Survey Toxic Waste--ground-water contamination study

USGS Publications Warehouse

1984-01-01

Recent investigations suggest that dispersion in aquifers is scale dependent and a function of the heterogeneity of aquifer materials. Theoretical stochastic studies indicate that determining hydraulic-conductivity variability in three dimensions is important in analyzing the dispersion process. Even though field methods are available to approximate hydraulic conductivity in three dimensions, the methods are not generally used because of high cost of field equipment and because measurement and analysis techniques are cumbersome and time consuming. The hypothesis of this study is that field-determined values of dispersivity are scale dependent and that they may be described as a function of hydraulic conductivity in three dimensions. The objectives of the study at the Bemidji research site are to (1) determine hydraulic conductivity of the porous media in three dimensions, (2) determine field values of dispersivity and its scale dependence on hydraulic conductivity, and (3) develop and apply a computerized data-collection, storage, and analysis system for field use in comprehensive determination of hydraulic conductivity and dispersivity. Plans for this investigation involve a variety of methods of analysis. Hydraulic conductivity will be determined separately in the horizontal and vertical planes of the hydraulic-conductivity ellipsoid. Field values of dispersivity will be determined by single-well and doublet-well injection or withdrawal tests with tracers. A computerized data-collection, storage, and analysis system to measure pressure, flow rate, tracer concentrations, and temperature will be designed for field testing. Real-time computer programs will be used to analyze field data. The initial methods of analysis will be utilized to meet the objectives of the study. Preliminary field data indicate the aquifer underlying the Bemidji site is vertically heterogeneous, cross-bedded outwash. Preliminary analysis of the flow field around a hypothetical doublet-well tracer test indicates that the location of the wells can affect the field value of dispersivity. Preliminary analysis also indicates that different values of dispersivity may result from anisotropic conditions in tests in which observation wells are located at equal radial distances from either the injection or withdrawal well.

Functioning in Women with Cervical Cancer in Brazil: the Perspective of Experts.

PubMed

Castaneda, Luciana; Bergmann, Anke; Castro, Shamyr; Koifman, Rosalina

2018-05-09

 The objective of this study was to identify the perspective of the specialists about functioning in women with cervical cancer (CC).  A study was conducted with specialists using the Delphi methodology. The specialist contacts were found in oncology organizations and associations, as well as in a referral hospital in the treatment of CC. The questions that the experts answered covered the biopsychosocial domains of the International Classification of Functioning, Disability and Health (ICF).  Twenty-five specialists participated in the study. The experts' responses generated 485 significant concepts. The categories that presented the highest frequencies of reporting by the specialists were health services, systems and policies; structure of the reproductive system; health professionals and sexual function.  Regarding the perception of the specialists, this study concluded that 24 categories of ICF are the most relevant in the context of functioning in women with CC. The results suggest that the biopsychosocial perspective was incorporated in the experts' perceptions about the functioning phenomenon in women with CC in Brazil. Thieme Revinter Publicações Ltda Rio de Janeiro, Brazil.

Video game training and the reward system.

PubMed

Lorenz, Robert C; Gleich, Tobias; Gallinat, Jürgen; Kühn, Simone

2015-01-01

Video games contain elaborate reinforcement and reward schedules that have the potential to maximize motivation. Neuroimaging studies suggest that video games might have an influence on the reward system. However, it is not clear whether reward-related properties represent a precondition, which biases an individual toward playing video games, or if these changes are the result of playing video games. Therefore, we conducted a longitudinal study to explore reward-related functional predictors in relation to video gaming experience as well as functional changes in the brain in response to video game training. Fifty healthy participants were randomly assigned to a video game training (TG) or control group (CG). Before and after training/control period, functional magnetic resonance imaging (fMRI) was conducted using a non-video game related reward task. At pretest, both groups showed strongest activation in ventral striatum (VS) during reward anticipation. At posttest, the TG showed very similar VS activity compared to pretest. In the CG, the VS activity was significantly attenuated. This longitudinal study revealed that video game training may preserve reward responsiveness in the VS in a retest situation over time. We suggest that video games are able to keep striatal responses to reward flexible, a mechanism which might be of critical value for applications such as therapeutic cognitive training.

Video game training and the reward system

PubMed Central

Lorenz, Robert C.; Gleich, Tobias; Gallinat, Jürgen; Kühn, Simone

2015-01-01

Video games contain elaborate reinforcement and reward schedules that have the potential to maximize motivation. Neuroimaging studies suggest that video games might have an influence on the reward system. However, it is not clear whether reward-related properties represent a precondition, which biases an individual toward playing video games, or if these changes are the result of playing video games. Therefore, we conducted a longitudinal study to explore reward-related functional predictors in relation to video gaming experience as well as functional changes in the brain in response to video game training. Fifty healthy participants were randomly assigned to a video game training (TG) or control group (CG). Before and after training/control period, functional magnetic resonance imaging (fMRI) was conducted using a non-video game related reward task. At pretest, both groups showed strongest activation in ventral striatum (VS) during reward anticipation. At posttest, the TG showed very similar VS activity compared to pretest. In the CG, the VS activity was significantly attenuated. This longitudinal study revealed that video game training may preserve reward responsiveness in the VS in a retest situation over time. We suggest that video games are able to keep striatal responses to reward flexible, a mechanism which might be of critical value for applications such as therapeutic cognitive training. PMID:25698962

History of cardiac anatomy: a comprehensive review from the Egyptians to today.

PubMed

Loukas, Marios; Youssef, Pamela; Gielecki, Jerzy; Walocha, Jerzy; Natsis, Kostantinos; Tubbs, R Shane

2016-04-01

The nature, function, and anatomy of the heart have been extensively studied since 3500 B.C. Greek and Egyptian science developed a basic understanding of the heart, although this was primarily related to religious beliefs. During the Hippocratic era, Hippocrates and his colleagues developed a more scientific and less religious understanding of the cardiovascular system. The post-Hippocratic era was characterized by more advanced descriptions of the location, structure, and function of the heart. The Alexandrian, Roman, Medieval Islamic, and European eras included turning points in the history of cardiac anatomy. Subsequently, after the structure and function of the heart were established, its connection with the lungs was investigated. Description of the pulmonary circulation was followed by the discovery of the conductive system and innervation of the heart. © 2016 Wiley Periodicals, Inc.

Variants of Transient Receptor Potential Melastatin Member 4 in Childhood Atrioventricular Block.

PubMed

Syam, Ninda; Chatel, Stéphanie; Ozhathil, Lijo Cherian; Sottas, Valentin; Rougier, Jean-Sébastien; Baruteau, Alban; Baron, Estelle; Amarouch, Mohamed-Yassine; Daumy, Xavier; Probst, Vincent; Schott, Jean-Jacques; Abriel, Hugues

2016-05-20

Transient receptor potential melastatin member 4 (TRPM4) is a nonselective cation channel. TRPM4 mutations have been linked to cardiac conduction disease and Brugada syndrome. The mechanisms underlying TRPM4-dependent conduction slowing are not fully understood. The aim of this study was to characterize TRPM4 genetic variants found in patients with congenital or childhood atrioventricular block. Ninety-one patients with congenital or childhood atrioventricular block were screened for candidate genes. Five rare TRPM4 genetic variants were identified and investigated. The variants were expressed heterologously in HEK293 cells. Two of the variants, A432T and A432T/G582S, showed decreased expression of the protein at the cell membrane; inversely, the G582S variant showed increased expression. Further functional characterization of these variants using whole-cell patch-clamp configuration showed a loss of function and a gain of function, respectively. We hypothesized that the observed decrease in expression was caused by a folding and trafficking defect. This was supported by the observation that incubation of these variants at lower temperature partially rescued their expression and function. Previous studies have suggested that altered SUMOylation of TRPM4 may cause a gain of function; however, we did not find any evidence that supports SUMOylation as being directly involved for the gain-of-function variant. This study underpins the role of TRPM4 in the cardiac conduction system. The loss-of-function variants A432T/G582S found in 2 unrelated patients with atrioventricular block are most likely caused by misfolding-dependent altered trafficking. The ability to rescue this variant with lower temperature may provide a novel use of pharmacological chaperones in treatment strategies. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Time course and predictors of median nerve conduction after carpal tunnel release.

PubMed

Rotman, Mitchell B; Enkvetchakul, Bobby V; Megerian, J Thomas; Gozani, Shai N

2004-05-01

To identify predictors of outcome and of electrophysiologic recovery in patients with carpal tunnel syndrome (CTS) treated by endoscopic carpal tunnel release using a nerve conduction testing system (NC-Stat; NEUROMetrix, Inc, Waltham, MA). Validity of the automated nerve conduction testing system was shown by comparing presurgical distal motor latencies (DMLs) against a reference obtained by referral to an electromyography laboratory. The DML was evaluated in 48 patients with CTS. Measurements were obtained within 1 hour of surgery and at 2 weeks, 6 weeks, 3 months, and 6 months after carpal tunnel release. Presurgical and postsurgical DMLs were then compared and correlated with variables and possible predictors of outcome including age, body mass index, gender, and presurgical DMLs. The automated nerve conduction testing system DMLs matched those of reference electromyography/nerve conduction study values with high correlation. Sensitivity of the automated nerve conduction testing system when compared with a standardized CTS case definition was 89%, with a specificity of 95%. A significant correlation was found between the DML before release and the DML 1 hour after release. Moreover, maximal postsurgical DML improvement was highly dependent on the presurgical DML, with no improvement shown for the <4-ms group, mild improvement for the 4-to-6-ms group, and maximal improvement in the >6-ms group. Among the clinical variables of age, gender, and body mass index only age was mildly predictive of postrelease DML changes at 6 months. No other correlations between clinical variables and postsurgical DMLs were significant. In addition the predictive value of age was lost when combined with the presurgical DML in a multivariate analysis. Postsurgical changes in the median nerve DML were highly dependent on the prerelease latency. The sensitivity and specificity of a nerve conduction monitoring system in detecting and aiding in the diagnosis of CTS is useful in the long-term management of patients with CTS and can aid in determining the level of improvement in median nerve function after endoscopic carpal tunnel release.

A systemic integrative framework to describe comprehensively a swine health system, Flanders as an example.

PubMed

Rojo-Gimeno, Cristina; Dewulf, Jeroen; Maes, Dominiek; Wauters, Erwin

2018-06-01

A well-functioning swine health system is crucial to ensure a sustainable pig production. Yet, little attention has been paid to understand it. The objective of this study was to unravel the complexity of a swine health system by using a systems-thinking approach for the case of Flanders (Northern part of Belgium). To that end, qualitative interviews were held with 33 relevant stakeholders. A hybrid thematic analysis was conducted which consisted of two phases. First, an inductive thematic analysis was conducted and second, the resulting themes were classified into the building blocks of a systemic framework. This framework combined a structural and a functional analysis that allowed to identify the key actors and their functions. Additionally, a transformational analysis was performed to evaluate how structures and the entire swine health system enable or disable functions. Findings revealed that the Flemish swine health system presents several merits such as the synchronization of policies and sector's agreements to reduce the antimicrobial use in the pig sector and the presence of a rich network of universities and research institutes that contribute to the education of health professionals. Nevertheless, several systemic failures were observed at different levels such as the lack of a good professional body representing the swine veterinarians, the tradition that veterinary advice is provided for 'free' by feed mill companies, and the shortage of reliable farm productivity data. Both latter failures may hinder swine practitioners to provide integrative advice. While few veterinarians are remunerated per hour or per visit by farmers, the most common business model used by veterinarians is largely based on the sale of medicines. Thus, veterinarians encounter often a conflict of interest when advising on preventive vaccinations and, in turn, farmers distrust their advice. On a positive note, alternatives to the traditional business model were suggested by both veterinarians and farmers which may indicate that there is intention to change; however, the broader institutional and socio-cultural environment does not enable this evolution. The results of this study can aid policy makers to anticipate the effects of proposed interventions and regulations so that they can be fine-tuned before they are enforced. Copyright © 2018 Elsevier B.V. All rights reserved.

NASA System Safety Handbook. Volume 2: System Safety Concepts, Guidelines, and Implementation Examples

NASA Technical Reports Server (NTRS)

Dezfuli, Homayoon; Benjamin, Allan; Everett, Christopher; Feather, Martin; Rutledge, Peter; Sen, Dev; Youngblood, Robert

2015-01-01

This is the second of two volumes that collectively comprise the NASA System Safety Handbook. Volume 1 (NASASP-210-580) was prepared for the purpose of presenting the overall framework for System Safety and for providing the general concepts needed to implement the framework. Volume 2 provides guidance for implementing these concepts as an integral part of systems engineering and risk management. This guidance addresses the following functional areas: 1.The development of objectives that collectively define adequate safety for a system, and the safety requirements derived from these objectives that are levied on the system. 2.The conduct of system safety activities, performed to meet the safety requirements, with specific emphasis on the conduct of integrated safety analysis (ISA) as a fundamental means by which systems engineering and risk management decisions are risk-informed. 3.The development of a risk-informed safety case (RISC) at major milestone reviews to argue that the systems safety objectives are satisfied (and therefore that the system is adequately safe). 4.The evaluation of the RISC (including supporting evidence) using a defined set of evaluation criteria, to assess the veracity of the claims made therein in order to support risk acceptance decisions.

Pressure Mapping Mat for Tele-Home Care Applications

PubMed Central

Saenz-Cogollo, Jose Francisco; Pau, Massimiliano; Fraboni, Beatrice; Bonfiglio, Annalisa

2016-01-01

In this paper we present the development of a mat-like pressure mapping system based on a single layer textile sensor and intended to be used in home environments for monitoring the physical condition of persons with limited mobility. The sensor is fabricated by embroidering silver-coated yarns on a light cotton fabric and creating pressure-sensitive resistive elements by stamping the conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) at the crossing points of conductive stitches. A battery-operated mat prototype was developed and includes the scanning circuitry and a wireless communication module. A functional description of the system is presented together with a preliminary experimental evaluation of the mat prototype in the extraction of plantar pressure parameters. PMID:26978369

Defining the functions of public health governance.

PubMed

Carlson, Valeria; Chilton, Marita J; Corso, Liza C; Beitsch, Leslie M

2015-04-01

We conducted a literature review in 2011 to determine if accepted governance functions continue to reflect the role of public health governing entities. Reviewing literature and other source documents, as well as consulting with practitioners, resulted in an iterative process that identified 6 functions of public health governance and established definitions for each of these: policy development; resource stewardship; continuous improvement; partner engagement; legal authority; and oversight of a health department. These functions provided context for the role of governing entities in public health practice and aligned well with existing public health accreditation standards. Public health systems research can build from this work in future explorations of the contributions of governance to health department performance.

Defining the Functions of Public Health Governance

PubMed Central

Chilton, Marita J.; Corso, Liza C.; Beitsch, Leslie M.

2015-01-01

We conducted a literature review in 2011 to determine if accepted governance functions continue to reflect the role of public health governing entities. Reviewing literature and other source documents, as well as consulting with practitioners, resulted in an iterative process that identified 6 functions of public health governance and established definitions for each of these: policy development; resource stewardship; continuous improvement; partner engagement; legal authority; and oversight of a health department. These functions provided context for the role of governing entities in public health practice and aligned well with existing public health accreditation standards. Public health systems research can build from this work in future explorations of the contributions of governance to health department performance. PMID:25689187

A consensus-based gold standard for the evaluation of mass casualty triage systems.

PubMed

Lerner, E Brooke; McKee, Courtney H; Cady, Charles E; Cone, David C; Colella, M Riccardo; Cooper, Arthur; Coule, Phillip L; Lairet, Julio R; Liu, J Marc; Pirrallo, Ronald G; Sasser, Scott M; Schwartz, Richard; Shepherd, Greene; Swienton, Raymond E

2015-01-01

Accuracy and effectiveness analyses of mass casualty triage systems are limited because there are no gold standard definitions for each of the triage categories. Until there is agreement on which patients should be identified by each triage category, it will be impossible to calculate sensitivity and specificity or to compare accuracy between triage systems. To develop a consensus-based, functional gold standard definition for each mass casualty triage category. National experts were recruited through the lead investigators' contacts and their suggested contacts. Key informant interviews were conducted to develop a list of potential criteria for defining each triage category. Panelists were interviewed in order of their availability until redundancy of themes was achieved. Panelists were blinded to each other's responses during the interviews. A modified Delphi survey was developed with the potential criteria identified during the interview and delivered to all recruited experts. In the early rounds, panelists could add, remove, or modify criteria. In the final rounds edits were made to the criteria until at least 80% agreement was achieved. Thirteen national and local experts were recruited to participate in the project. Six interviews were conducted. Three rounds of voting were performed, with 12 panelists participating in the first round, 12 in the second round, and 13 in the third round. After the first two rounds, the criteria were modified according to respondent suggestions. In the final round, over 90% agreement was achieved for all but one criterion. A single e-mail vote was conducted on edits to the final criterion and consensus was achieved. A consensus-based, functional gold standard definition for each mass casualty triage category was developed. These gold standard definitions can be used to evaluate the accuracy of mass casualty triage systems after an actual incident, during training, or for research.

Utilization of artificial intelligence techniques for the Space Station power system

NASA Technical Reports Server (NTRS)

Evatt, Thomas C.; Gholdston, Edward W.

1988-01-01

Due to the complexity of the Space Station Electrical Power System (EPS) as currently envisioned, artificial intelligence/expert system techniques are being investigated to automate operations, maintenance, and diagnostic functions. A study was conducted to investigate this technology as it applies to failure detection, isolation, and reconfiguration (FDIR) and health monitoring of power system components and of the total system. Control system utilization of expert systems for load scheduling and shedding operations was also researched. A discussion of the utilization of artificial intelligence/expert systems for Initial Operating Capability (IOC) for the Space Station effort is presented along with future plans at Rocketdyne for the utilization of this technology for enhanced Space Station power capability.

Web-based applications for building, managing and analysing kinetic models of biological systems.

PubMed

Lee, Dong-Yup; Saha, Rajib; Yusufi, Faraaz Noor Khan; Park, Wonjun; Karimi, Iftekhar A

2009-01-01

Mathematical modelling and computational analysis play an essential role in improving our capability to elucidate the functions and characteristics of complex biological systems such as metabolic, regulatory and cell signalling pathways. The modelling and concomitant simulation render it possible to predict the cellular behaviour of systems under various genetically and/or environmentally perturbed conditions. This motivates systems biologists/bioengineers/bioinformaticians to develop new tools and applications, allowing non-experts to easily conduct such modelling and analysis. However, among a multitude of systems biology tools developed to date, only a handful of projects have adopted a web-based approach to kinetic modelling. In this report, we evaluate the capabilities and characteristics of current web-based tools in systems biology and identify desirable features, limitations and bottlenecks for further improvements in terms of usability and functionality. A short discussion on software architecture issues involved in web-based applications and the approaches taken by existing tools is included for those interested in developing their own simulation applications.

Enhancing Leadership and Governance Competencies to Strengthen Health Systems in Nigeria: Assessment of Organizational Human Resources Development

PubMed Central

Uneke, Chigozie J.; Ezeoha, Abel E.; Ndukwe, Chinwendu D.; Oyibo, Patrick G.; Onwe, Fri Day

2012-01-01

The lack of effective leadership and governance in the health sector has remained a major challenge in Nigeria and contributes to the failure of health systems and poor development of human resources. In this cross-sectional intervention study, leadership and governance competencies of policy makers were enhanced through a training workshop, and an assessment was conducted of organizational activities designed to promote evidence-informed leadership and governance to improve human resources for health (HRH). The training workshop increased the understanding of policy makers with regard to leadership and governance factors that ensure the functionality of health systems and improve human resources development, including policy guidance, intelligence and oversight, collaboration and coalition building, regulation, system design and accountability. Findings indicated that systems for human resources development exist in all participants' organizations, but the functionality of these systems was suboptimal. More systematic and standardized processes are required to improve competencies of leadership and governance for better human resources development in low-income settings. PMID:23372582

Autonomous biological system-an unique method of conducting long duration space flight experiments for pharmaceutical and gravitational biology research

NASA Astrophysics Data System (ADS)

Anderson, G. A.; MacCallum, T. K.; Poynter, J. E.; Klaus, D., Dr.

1998-01-01

Paragon Space Development Corporation (SDC) has developed an Autonomous Biological System (ABS) that can be flown in space to provide for long term growth and breeding of aquatic plants, animals, microbes and algae. The system functions autonomously and in isolation from the spacecraft life support systems and with no mandatory crew time required for function or observation. The ABS can also be used for long term plant and animal life support and breeding on a free flyer space craft. The ABS units are a research tool for both pharmaceutical and basic space biological sciences. Development flights in May of 1996 and September, 1996 through January, 1997 were largely successful, showing both that the hardware and life systems are performing with beneficial results, though some surprises were still found. The two space flights, plus the current flight now on Mir, are expected to result in both a scientific and commercially usable system for breeding and propagation of animals and plants in space.

History of POIC Capabilities and Limitations to Conduct International Space Station Payload Operations

NASA Technical Reports Server (NTRS)

Grimaldi, Rebecca; Horvath, Tim; Morris, Denise; Willis, Emily; Stacy, Lamar; Shell, Mike; Faust, Mark; Norwood, Jason

2011-01-01

Payload science operations on the International Space Station (ISS) have been conducted continuously twenty-four hours per day, 365 days a year beginning February, 2001 and continuing through present day. The Payload Operations Integration Center (POIC), located at the Marshall Space Flight Center in Huntsville, Alabama, has been a leader in integrating and managing NASA distributed payload operations. The ability to conduct science operations is a delicate balance of crew time, onboard vehicle resources, hardware up-mass to the vehicle, and ground based flight control team manpower. Over the span of the last ten years, the POIC flight control team size, function, and structure has been modified several times commensurate with the capabilities and limitations of the ISS program. As the ISS vehicle has been expanded and its systems changed throughout the assembly process, the resources available to conduct science and research have also changed. Likewise, as ISS program financial resources have demanded more efficiency from organizations across the program, utilization organizations have also had to adjust their functionality and structure to adapt accordingly. The POIC has responded to these often difficult challenges by adapting our team concept to maximize science research return within the utilization allocations and vehicle limitations that existed at the time. In some cases, the ISS and systems limitations became the limiting factor in conducting science. In other cases, the POIC structure and flight control team size were the limiting factors, so other constraints had to be put into place to assure successful science operations within the capabilities of the POIC. This paper will present the POIC flight control team organizational changes responding to significant events of the ISS and Shuttle programs.

Theoretical and experimental studies on wide-band-gap p-type conductive BaCuSeF and related compounds

NASA Astrophysics Data System (ADS)

Sakakima, Hiroshi; Nishitani, Mikihiko; Yamamoto, Koichi; Wada, Takahiro

2015-08-01

BaCuSeF and related compounds, MCuQF (M = Ba, Sr; Q = Se, S), are known to show p-type conduction. The formation energies of the Cu vacancy ΔH[VCu] in a MCuQF system were computed by first-principles calculation with a generalized gradient approximation (GGA) of the Perdew-Burke-Ernzerhof (PBE) functional as an electron exchange and correlation functional. The density of states (DOS) of BaCuSeF was calculated with the hybrid functional of Heyd-Scuseria-Ernzerhof (HSE) 06. ΔH[VCu] was found to be very small under both the Cu- and Q-rich conditions, which probably contributes to p-type conduction. The electronic structure of BaCuSeF was studied by X-ray photoelectron spectroscopy (XPS) with UV photoelectron yield spectroscopy (UVPYS) and photoemission yield spectroscopy (PYS). The determined depth of the top of the valence band relative to the vacuum level was about 4.9 eV. This value is desirable for applications in compound semiconductor thin-film tandem solar cells since the absorbers of polycrystalline thin-film solar cells, such as CdTe and Cu(In,Ga)Se2, are p-type semiconductors. The DOS of BaCuSeF calculated with the HSE06 functional was almost consistent with the XPS spectrum.

The trigger system for the external target experiment in the HIRFL cooling storage ring

NASA Astrophysics Data System (ADS)

Li, Min; Zhao, Lei; Liu, Jin-Xin; Lu, Yi-Ming; Liu, Shu-Bin; An, Qi

2016-08-01

A trigger system was designed for the external target experiment in the Cooling Storage Ring (CSR) of the Heavy Ion Research Facility in Lanzhou (HIRFL). Considering that different detectors are scattered over a large area, the trigger system is designed based on a master-slave structure and fiber-based serial data transmission technique. The trigger logic is organized in hierarchies, and flexible reconfiguration of the trigger function is achieved based on command register access or overall field-programmable gate array (FPGA) logic on-line reconfiguration controlled by remote computers. We also conducted tests to confirm the function of the trigger electronics, and the results indicate that this trigger system works well. Supported by the National Natural Science Foundation of China (11079003), the Knowledge Innovation Program of the Chinese Academy of Sciences (KJCX2-YW-N27), and the CAS Center for Excellence in Particle Physics (CCEPP).

Distributed Adaptive Fuzzy Control for Nonlinear Multiagent Systems Via Sliding Mode Observers.

PubMed

Shen, Qikun; Shi, Peng; Shi, Yan

2016-12-01

In this paper, the problem of distributed adaptive fuzzy control is investigated for high-order uncertain nonlinear multiagent systems on directed graph with a fixed topology. It is assumed that only the outputs of each follower and its neighbors are available in the design of its distributed controllers. Equivalent output injection sliding mode observers are proposed for each follower to estimate the states of itself and its neighbors, and an observer-based distributed adaptive controller is designed for each follower to guarantee that it asymptotically synchronizes to a leader with tracking errors being semi-globally uniform ultimate bounded, in which fuzzy logic systems are utilized to approximate unknown functions. Based on algebraic graph theory and Lyapunov function approach, using Filippov-framework, the closed-loop system stability analysis is conducted. Finally, numerical simulations are provided to illustrate the effectiveness and potential of the developed design techniques.

Orbit transfer rocket engine integrated control and health monitoring system technology readiness assessment

NASA Technical Reports Server (NTRS)

Bickford, R. L.; Collamore, F. N.; Gage, M. L.; Morgan, D. B.; Thomas, E. R.

1992-01-01

The objectives of this task were to: (1) estimate the technology readiness of an integrated control and health monitoring (ICHM) system for the Aerojet 7500 lbF Orbit Transfer Vehicle engine preliminary design assuming space based operations; and (2) estimate the remaining cost to advance this technology to a NASA defined 'readiness level 6' by 1996 wherein the technology has been demonstrated with a system validation model in a simulated environment. The work was accomplished through the conduct of four subtasks. In subtask 1 the minimally required functions for the control and monitoring system was specified. The elements required to perform these functions were specified in Subtask 2. In Subtask 3, the technology readiness level of each element was assessed. Finally, in Subtask 4, the development cost and schedule requirements were estimated for bringing each element to 'readiness level 6'.

Warming and Elevated CO2 Interact to Drive Rapid Shifts in Marine Community Production.

PubMed

Sorte, Cascade J B; Bracken, Matthew E S

2015-01-01

Predicting the outcome of future climate change requires an understanding of how alterations in multiple environmental factors manifest in natural communities and affect ecosystem functioning. We conducted an in situ, fully factorial field manipulation of CO2 and temperature on a rocky shoreline in southeastern Alaska, USA. Warming strongly impacted functioning of tide pool systems within one month, with the rate of net community production (NCP) more than doubling in warmed pools under ambient CO2 levels relative to initial NCP values. However, in pools with added CO2, NCP was unaffected by warming. Productivity responses paralleled changes in the carbon-to-nitrogen ratio of a red alga, the most abundant primary producer species in the system, highlighting the direct link between physiology and ecosystem functioning. These observed changes in algal physiology and community productivity in response to our manipulations indicate the potential for natural systems to shift rapidly in response to changing climatic conditions and for multiple environmental factors to act antagonistically.

Warming and Elevated CO2 Interact to Drive Rapid Shifts in Marine Community Production

PubMed Central

Sorte, Cascade J. B.; Bracken, Matthew E. S.

2015-01-01

Predicting the outcome of future climate change requires an understanding of how alterations in multiple environmental factors manifest in natural communities and affect ecosystem functioning. We conducted an in situ, fully factorial field manipulation of CO2 and temperature on a rocky shoreline in southeastern Alaska, USA. Warming strongly impacted functioning of tide pool systems within one month, with the rate of net community production (NCP) more than doubling in warmed pools under ambient CO2 levels relative to initial NCP values. However, in pools with added CO2, NCP was unaffected by warming. Productivity responses paralleled changes in the carbon-to-nitrogen ratio of a red alga, the most abundant primary producer species in the system, highlighting the direct link between physiology and ecosystem functioning. These observed changes in algal physiology and community productivity in response to our manipulations indicate the potential for natural systems to shift rapidly in response to changing climatic conditions and for multiple environmental factors to act antagonistically. PMID:26714167

Extended use of electronic health records by primary care physicians: Does the electronic health record artefact matter?

PubMed

Raymond, Louis; Paré, Guy; Marchand, Marie

2017-04-01

The deployment of electronic health record systems is deemed to play a decisive role in the transformations currently being implemented in primary care medical practices. This study aims to characterize electronic health record systems from the perspective of family physicians. To achieve this goal, we conducted a survey of physicians practising in private clinics located in Quebec, Canada. We used valid responses from 331 respondents who were found to be representative of the larger population. Data provided by the physicians using the top three electronic health record software products were analysed in order to obtain statistically adequate sub-sample sizes. Significant differences were observed among the three products with regard to their functional capability. The extent to which each of the electronic health record functionalities are used by physicians also varied significantly. Our results confirm that the electronic health record artefact 'does matter', its clinical functionalities explaining why certain physicians make more extended use of their system than others.

Modeling our understanding of the His-Purkinje system.

PubMed

Vigmond, Edward J; Stuyvers, Bruno D

2016-01-01

The His-Purkinje System (HPS) is responsible for the rapid electric conduction in the ventricles. It relays electrical impulses from the atrioventricular node to the muscle cells and, thus, coordinates the contraction of ventricles in order to ensure proper cardiac pump function. The HPS has been implicated in the genesis of ventricular tachycardia and fibrillation as a source of ectopic beats, as well as forming distinct portions of reentry circuitry. Despite its importance, it remains much less well characterized, structurally and functionally, than the myocardium. Notably, important differences exist with regard to cell structure and electrophysiology, including ion channels, intracellular calcium handling, and gap junctions. Very few computational models address the HPS, and the majority of organ level modeling studies omit it. This review will provide an overview of our current knowledge of structure and function (including electrophysiology) of the HPS. We will review the most recent advances in modeling of the system from the single cell to the organ level, with considerations for relevant interspecies distinctions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Application of SNMP on CATV

NASA Astrophysics Data System (ADS)

Huang, Hong-bin; Liu, Wei-ping; Chen, Shun-er; Zheng, Liming

2005-02-01

A new type of CATV network management system developed by universal MCU, which supports SNMP, is proposed in this paper. From the point of view in both hardware and software, the function and method of every modules inside the system, which include communications in the physical layer, protocol process, data process, and etc, are analyzed. In our design, the management system takes IP MAN as data transmission channel and every controlled object in the management structure has a SNMP agent. In the SNMP agent developed, there are four function modules, including physical layer communication module, protocol process module, internal data process module and MIB management module. In the paper, the structure and function of every module are designed and demonstrated while the related hardware circuit, software flow as well as the experimental results are tested. Furthermore, by introducing RTOS into the software programming, the universal MCU procedure can conducts such multi-thread management as fast Ethernet controller driving, TCP/IP process, serial port signal monitoring and so on, which greatly improves efficiency of CPU.

The one step fermionic ladder

NASA Astrophysics Data System (ADS)

Das, Joy Prakash; Setlur, Girish S.

2017-10-01

The one step fermionic ladder refers to two parallel Luttinger Liquids (poles of the ladder) placed such that there is a finite probability of electrons hopping between the two poles at a pair of opposing points along each of the poles. The many-body Green function for such a system is calculated in presence of forward scattering interactions using the powerful non-chiral bosonization technique (NCBT). This technique is based on a non-standard harmonic analysis of the rapidly varying parts of the density fields appropriate for the study of strongly inhomogeneous ladder systems. The closed analytical expression for the correlation function obtained from NCBT is nothing but the series involving the RPA (Random Phase Approximation) diagrams in powers of the forward scattering coupling strength resummed to include only the most singular terms with the source of inhomogeneities treated exactly. Finally the correlation functions are used to study physical phenomena such as Friedel oscillations and the conductance of such systems with the potential difference applied across various ends.

Sensitivity of Space Launch System Buffet Forcing Functions to Buffet Mitigation Options

NASA Technical Reports Server (NTRS)

Piatak, David J.; Sekula, Martin K.; Rausch, Russ D.

2016-01-01

Time-varying buffet forcing functions arise from unsteady aerodynamic pressures and are one of many load environments, which contribute to the overall loading condition of a launch vehicle during ascent through the atmosphere. The buffet environment is typically highest at transonic conditions and can excite the vehicle dynamic modes of vibration. The vehicle response to these buffet forcing functions may cause high structural bending moments and vibratory environments, which can exceed the capabilities of the structure, or of vehicle components such as payloads and avionics. Vehicle configurations, protuberances, payload fairings, and large changes in stage diameter can trigger undesirable buffet environments. The Space Launch System (SLS) multi-body configuration and its structural dynamic characteristics presented challenges to the load cycle design process with respect to buffet-induced loads and responses. An initial wind-tunnel test of a 3-percent scale SLS rigid buffet model was conducted in 2012 and revealed high buffet environments behind the booster forward attachment protuberance, which contributed to reduced vehicle structural margins. Six buffet mitigation options were explored to alleviate the high buffet environments including modified booster nose cones and fences/strakes on the booster and core. These studies led to a second buffet test program that was conducted in 2014 to assess the ability of the buffet mitigation options to reduce buffet environments on the vehicle. This paper will present comparisons of buffet forcing functions from each of the buffet mitigation options tested, with a focus on sectional forcing function rms levels within regions of the vehicle prone to high buffet environments.

Configuration management issues and objectives for a real-time research flight test support facility

NASA Technical Reports Server (NTRS)

Yergensen, Stephen; Rhea, Donald C.

1988-01-01

An account is given of configuration management activities for the Western Aeronautical Test Range (WATR) at NASA-Ames, whose primary function is the conduct of aeronautical research flight testing through real-time processing and display, tracking, and communications systems. The processing of WATR configuration change requests for specific research flight test projects must be conducted in such a way as to refrain from compromising the reliability of WATR support to all project users. Configuration management's scope ranges from mission planning to operations monitoring and performance trend analysis.

Determination of Optimal Heat-Storage Thickness of Layer for “Smart Wall” by Methods of Nonlinear Heat Conduction Equations for Phase-transition Materials

NASA Astrophysics Data System (ADS)

Pospelova, I.

2017-11-01

The article suggests an original way of keeping heat load and its compensation for a microclimate system by proposing the “Smart Wall”. The construction consists of specially combined composite materials including phase-transition materials. The method for determination of the layer thickness is proposed for a certain accumulation time. Varying the thickness and composition of the layer it is possible to achieve a low amount of the thermal conductivity coefficient and to obtain various functional characteristics of fences.

A spectral method determination of the first critical Rayleigh number for a low-Prandtl number crystal melt in a cylindrical container

NASA Technical Reports Server (NTRS)

Dietz, C. M., Jr.; Diplas, P.

1993-01-01

The onset of laminar axisymmetric Rayleigh-Benard convection is investigated for a low-Prandtl number liquid metal in a cylindrical container. All surfaces are considered to be solid and no-slip. Two separate cases are examined for the thermal boundary conditions at the side wall, one with conducting and the other with insulated surface. The governing Boussinesq system is first perturbed and then simplified by introducing a Stokes stream function. Subsequently, a Chebyshev Galerkin spectral model is employed to reduce the simplified system to a system of first-order nonlinear ordinary differential equations. A local stability analysis determines the two values of the first critical Rayleigh number, Ra(sub cl), for the insulated and conducting side walls. As expected, the conducting Ra(sub cl) value of 2882.5 obtained from the present approach exceeded the corresponding insulated Ra(sub cl) value of 2331.6. For the insulated case, an earlier study using a different numerical approach suggests that Ra(sub cl) = 2261.9, while an experimental study measured Ra(sub cl) = 2700.

Cancer systems biology in the genome sequencing era: part 1, dissecting and modeling of tumor clones and their networks.

PubMed

Wang, Edwin; Zou, Jinfeng; Zaman, Naif; Beitel, Lenore K; Trifiro, Mark; Paliouras, Miltiadis

2013-08-01

Recent tumor genome sequencing confirmed that one tumor often consists of multiple cell subpopulations (clones) which bear different, but related, genetic profiles such as mutation and copy number variation profiles. Thus far, one tumor has been viewed as a whole entity in cancer functional studies. With the advances of genome sequencing and computational analysis, we are able to quantify and computationally dissect clones from tumors, and then conduct clone-based analysis. Emerging technologies such as single-cell genome sequencing and RNA-Seq could profile tumor clones. Thus, we should reconsider how to conduct cancer systems biology studies in the genome sequencing era. We will outline new directions for conducting cancer systems biology by considering that genome sequencing technology can be used for dissecting, quantifying and genetically characterizing clones from tumors. Topics discussed in Part 1 of this review include computationally quantifying of tumor subpopulations; clone-based network modeling, cancer hallmark-based networks and their high-order rewiring principles and the principles of cell survival networks of fast-growing clones. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Sensorimotor System Measurement Techniques

PubMed Central

Riemann, Bryan L.; Myers, Joseph B.; Lephart, Scott M.

2002-01-01

Objective: To provide an overview of currently available sensorimotor assessment techniques. Data Sources: We drew information from an extensive review of the scientific literature conducted in the areas of proprioception, neuromuscular control, and motor control measurement. Literature searches were conducted using MEDLINE for the years 1965 to 1999 with the key words proprioception, somatosensory evoked potentials, nerve conduction testing, electromyography, muscle dynamometry, isometric, isokinetic, kinetic, kinematic, posture, equilibrium, balance, stiffness, neuromuscular, sensorimotor, and measurement. Additional sources were collected using the reference lists of identified articles. Data Synthesis: Sensorimotor measurement techniques are discussed with reference to the underlying physiologic mechanisms, influential factors and locations of the variable within the system, clinical research questions, limitations of the measurement technique, and directions for future research. Conclusions/Recommendations: The complex interactions and relationships among the individual components of the sensorimotor system make measuring and analyzing specific characteristics and functions difficult. Additionally, the specific assessment techniques used to measure a variable can influence attained results. Optimizing the application of sensorimotor research to clinical settings can, therefore, be best accomplished through the use of common nomenclature to describe underlying physiologic mechanisms and specific measurement techniques. PMID:16558672

Identification of visual evoked response parameters sensitive to pilot mental state

NASA Technical Reports Server (NTRS)

Zacharias, G. L.

1988-01-01

Systems analysis techniques were developed and demonstrated for modeling the electroencephalographic (EEG) steady state visual evoked response (ssVER), for use in EEG data compression and as an indicator of mental workload. The study focused on steady state frequency domain stimulation and response analysis, implemented with a sum-of-sines (SOS) stimulus generator and an off-line describing function response analyzer. Three major tasks were conducted: (1) VER related systems identification material was reviewed; (2) Software for experiment control and data analysis was developed and implemented; and (3) ssVER identification and modeling was demonstrated, via a mental loading experiment. It was found that a systems approach to ssVER functional modeling can serve as the basis for eventual development of a mental workload indicator. The review showed how transient visual evoked response (tVER) and ssVER research are related at the functional level, the software development showed how systems techniques can be used for ssVER characterization, and the pilot experiment showed how a simple model can be used to capture the basic dynamic response of the ssVER, under varying loads.

Optimality and Conductivity for Water Flow: From Landscapes, to Unsaturated Soils, to Plant Leaves

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

Liu, H.H.

2012-02-23

Optimality principles have been widely used in many areas. Based on an optimality principle that any flow field will tend toward a minimum in the energy dissipation rate, this work shows that there exists a unified form of conductivity relationship for three different flow systems: landscapes, unsaturated soils and plant leaves. The conductivity, the ratio of water flux to energy gradient, is a power function of water flux although the power value is system dependent. This relationship indicates that to minimize energy dissipation rate for a whole system, water flow has a small resistance (or a large conductivity) at amore » location of large water flux. Empirical evidence supports validity of the relationship for landscape and unsaturated soils (under gravity dominated conditions). Numerical simulation results also show that the relationship can capture the key features of hydraulic structure for a plant leaf, although more studies are needed to further confirm its validity. Especially, it is of interest that according to this relationship, hydraulic conductivity for gravity-dominated unsaturated flow, unlike that defined in the classic theories, depends on not only capillary pressure (or saturation), but also the water flux. Use of the optimality principle allows for determining useful results that are applicable to a broad range of areas involving highly non-linear processes and may not be possible to obtain from classic theories describing water flow processes.« less

The MPC&A Questionnaire

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

Powell, Danny H; Elwood Jr, Robert H

The questionnaire is the instrument used for recording performance data on the nuclear material protection, control, and accountability (MPC&A) system at a nuclear facility. The performance information provides a basis for evaluating the effectiveness of the MPC&A system. The goal for the questionnaire is to provide an accurate representation of the performance of the MPC&A system as it currently exists in the facility. Performance grades for all basic MPC&A functions should realistically reflect the actual level of performance at the time the survey is conducted. The questionnaire was developed after testing and benchmarking the material control and accountability (MC&A) systemmore » effectiveness tool (MSET) in the United States. The benchmarking exercise at the Idaho National Laboratory (INL) proved extremely valuable for improving the content and quality of the early versions of the questionnaire. Members of the INL benchmark team identified many areas of the questionnaire where questions should be clarified and areas where additional questions should be incorporated. The questionnaire addresses all elements of the MC&A system. Specific parts pertain to the foundation for the facility's overall MPC&A system, and other parts pertain to the specific functions of the operational MPC&A system. The questionnaire includes performance metrics for each of the basic functions or tasks performed in the operational MPC&A system. All of those basic functions or tasks are represented as basic events in the MPC&A fault tree. Performance metrics are to be used during completion of the questionnaire to report what is actually being done in relation to what should be done in the performance of MPC&A functions.« less

Survey of on-road image projection with pixel light systems

NASA Astrophysics Data System (ADS)

Rizvi, Sadiq; Knöchelmann, Marvin; Ley, Peer-Phillip; Lachmayer, Roland

2017-12-01

HID, LED and laser-based high resolution automotive headlamps, as of late known as `pixel light systems', are at the forefront of the developing technologies paving the way for autonomous driving. In addition to light distribution capabilities that outperform Adaptive Front Lighting and Matrix Beam systems, pixel light systems provide the possibility of image projection directly onto the street. The underlying objective is to improve the driving experience, in any given scenario, in terms of safety, comfort and interaction for all road users. The focus of this work is to conduct a short survey on this state-of-the-art image projection functionality. A holistic research regarding the image projection functionality can be divided into three major categories: scenario selection, technological development and evaluation design. Consequently, the work presented in this paper is divided into three short studies. Section 1 provides a brief introduction to pixel light systems and a justification for the approach adopted for this study. Section 2 deals with the selection of scenarios (and driving maneuvers) where image projection can play a critical role. Section 3 discusses high power LED and LED array based prototypes that are currently under development. Section 4 demonstrates results from an experiment conducted to evaluate the illuminance of an image space projected using a pixel light system prototype developed at the Institute of Product Development (IPeG). Findings from this work can help to identify and advance future research work relating to: further development of pixel light systems, scenario planning, examination of optimal light sources, behavioral response studies etc.

Telecommunication service markets through the year 2000 in relation to millimeter wave satellite systems

NASA Technical Reports Server (NTRS)

Stevenson, S. M.

1979-01-01

NASA is currently conducting a series of millimeter wave satellite system market studies to develop 30/20 GHz satellite system concepts that have commercial potential. Four contractual efforts were undertaken: two parallel and independent system studies and two parallel and independent market studies. The marketing efforts are focused on forecasting the total domestic demand for long haul telecommunications services for the 1980-2000 period. Work completed to date and reported in this paper include projections of: geographical distribution of traffic; traffic volume as a function of urban area size; and user identification and forecasted demand.

In-situ Subaqueous Capping of Mercury-Contaminated Sediments in a Fresh-Water Aquatic System, Part I-Bench-Scale Microcosm Study to Assess Methylmercury Production

EPA Science Inventory

Bench-scale microcosm experiments were designed to provide a better understanding of the potential for Hg methylation in sediments from an aquatic environment. Experiments were conducted to examine the function of sulfate concentration, lactate concentration, the presence/absenc...

Applying Item Response Theory Modeling in Educational Research

ERIC Educational Resources Information Center

Le, Dai-Trang

2013-01-01

In an effort to understand how school boards in America's K-12 school system function, a research collaboration was undertaken among four agencies: the National School Boards Association, the Thomas B. Fordham Institute, the Iowa Association of School Boards, and the Wallace Foundation. These groups joined effort to conduct research on school…

Uncertainty Quantification using Epi-Splines and Soft Information

DTIC Science & Technology

2012-06-01

use of the Kullback - Leibler divergence measure. The Kullback - Leibler ...to illustrate the application of soft information related to the Kullback - Leibler (KL) divergence discussed in Chapter 2. The idea behind apply- ing... information for the estimation of system performance density functions in order to quantify uncertainty. We conduct empirical testing of

Materials management: stretching the "household" budget.

PubMed

Carpe, R H; Carroll, P E

1987-11-01

As CFOs assume responsibility for the materials management function because of the potential to maximize cash flow, achieve economies of scale, decrease costs, and streamline operations, they look for guidelines to evaluate performance. Conducting a systems operations audit can aid in assessing that performance. CFOs can determine whether materials management processes are working "smarter, nor harder."

An Investigation of Possible Correlations Between Individual Pilot Performance and Neurological Functions.

DTIC Science & Technology

1977-05-23

ed these findings with tests on peptic ulcer patients.1’ In 1949, Sau l , using a psychoanalytic approach in searching for correlates of personality...this area : PILOT PERFOR MANCE ANA L YSIS 1) With respect to the system developed and used for this study, research should be conducted to determine

Quasi one-dimensional band dispersion and surface metallization in long-range ordered polymeric wires

DOE PAGES

Vasseur, Guillaume; Fagot-Revurat, Yannick; Sicot, Muriel; ...

2016-01-04

We study the electronic structure of an ordered array of poly(para-phenylene) chains produced by surface-catalyzed dehalogenative polymerization of 1,4-dibromobenzene on copper (110). The quantization of unoccupied molecular states is measured as a function of oligomer length by scanning tunnelling spectroscopy, with Fermi level crossings observed for chains longer than ten phenyl rings. Angle-resolved photoelectron spectroscopy reveals a quasi-one-dimensional valence band as well as a direct gap of 1.15 eV, as the conduction band is partially filled through adsorption on the surface. Tight-binding modelling and ab initio density functional theory calculations lead to a full description of the organic band-structure, includingmore » the k-dispersion, the gap size and electron charge transfer mechanisms, highlighting a strong substrate-molecule interaction that drives the system into a metallic behaviour. In summary, we have fully characterized the band structure of a carbon-based conducting wire. This model system may be considered as a fingerprint of -conjugation of surface organic frameworks.« less

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

Ünal, Hatice; Mete, Ersen, E-mail: emete@balikesir.edu.tr; Gunceler, Deniz

The adsorption of two different organic molecules cyanidin glucoside (C{sub 21}O{sub 11}H{sub 20}) and TA-St-CA on anatase (101) and (001) nanowires has been investigated using the standard and the range separated hybrid density functional theory calculations. The electronic structures and optical spectra of resulting dye–nanowire combined systems show distinct features for these types of photochromophores. The lowest unoccupied molecular orbital of the natural dye cyanidin glucoside is located below the conduction band of the semiconductor while, in the case of TA-St-CA, it resonates with the states inside the conduction band. The wide-bandgap anatase nanowires can be functionalized for solar cellsmore » through electron-hole generation and subsequent charge injection by these dye sensitizers. The intermolecular charge transfer character of Donor-π-Acceptor type dye TA-St-CA is substantially modified by its adsorption on TiO{sub 2} surfaces. Cyanidin glucoside exhibits relatively stronger anchoring on the nanowires through its hydroxyl groups. The atomic structures of dye–nanowire systems re-optimized with the inclusion of nonlinear solvation effects showed that the binding strengths of both dyes remain moderate even in ionic solutions.« less

Long-Term Evolution Electromagnetic Fields Exposure Modulates the Resting State EEG on Alpha and Beta Bands.

PubMed

Yang, Lei; Chen, Qinghua; Lv, Bin; Wu, Tongning

2017-05-01

Long-term evolution (LTE) wireless telecommunication systems are widely used globally, which has raised a concern that exposure to electromagnetic fields (EMF) emitted from LTE devices can change human neural function. To date, few studies have been conducted on the effect of exposure to LTE EMF. Here, we evaluated the changes in electroencephalogram (EEG) due to LTE EMF exposure. An LTE EMF exposure system with a stable power emission, which was equivalent to the maximum emission from an LTE mobile phone, was used to radiate the subjects. Numerical simulations were conducted to ensure that the specific absorption rate in the subject's head was below the safety limits. Exposure to LTE EMF reduced the spectral power and the interhemispheric coherence in the alpha and beta bands of the frontal and temporal brain regions. No significant change was observed in the spectral power and the inter-hemispheric coherence in different timeslots during and after the exposure. These findings also corroborated those of our previous study using functional magnetic resonant imaging.

Family dynamics during the grieving process: a systematic literature review.

PubMed

Delalibera, Mayra; Presa, Joana; Coelho, Alexandra; Barbosa, António; Franco, Maria Helena Pereira

2015-04-01

The loss of a loved one can affect family dynamics by changing the family system and creating the need for family members to reorganize. Good family functioning, which is characterized by open communication, expression of feelings and thoughts and cohesion among family members, facilitates adaptive adjustment to the loss. This study conducted a systematic review of the literature on family dynamics during the grieving process. A search was conducted in the EBSCO, Web of Knowledge and Bireme databases for scientific articles published from January 1980 to June 2013. Of the 389 articles found, only 15 met all the inclusion criteria. The selected studies provided evidence that dysfunctional families exhibit more psychopathological symptoms, more psychosocial morbidity, poorer social functioning, greater difficulty accessing community resources, lower functional capacity at work, and a more complicated grieving process. Family conflicts were also emphasized as contributing to the development of a complicated grieving process, while cohesion, expression of affection and good communication in families are believed to mitigate grief symptoms.

Organization and evolution of parieto-frontal processing streams in macaque monkeys and humans.

PubMed

Caminiti, Roberto; Innocenti, Giorgio M; Battaglia-Mayer, Alexandra

2015-09-01

The functional organization of the parieto-frontal system is crucial for understanding cognitive-motor behavior and provides the basis for interpreting the consequences of parietal lesions in humans from a neurobiological perspective. The parieto-frontal connectivity defines some main information streams that, rather than being devoted to restricted functions, underlie a rich behavioral repertoire. Surprisingly, from macaque to humans, evolution has added only a few, new functional streams, increasing however their complexity and encoding power. In fact, the characterization of the conduction times of parietal and frontal areas to different target structures has recently opened a new window on cortical dynamics, suggesting that evolution has amplified the probability of dynamic interactions between the nodes of the network, thanks to communication patterns based on temporally-dispersed conduction delays. This might allow the representation of sensory-motor signals within multiple neural assemblies and reference frames, as to optimize sensory-motor remapping within an action space characterized by different and more complex demands across evolution. Copyright © 2015 Elsevier Ltd. All rights reserved.

Low temperature growth and electrical characterization of insulators for GaAs MISFETS

NASA Technical Reports Server (NTRS)

Borrego, J. M.; Ghandhi, S. K.

1981-01-01

Progress in the low temperature growth of oxides and layers on GaAs and the detailed electrical characterization of these oxides is reported. A plasma anodization system was designed, assembled, and put into operation. A measurement system was assembled for determining capacitance and conductance as a function of gate voltage for frequencies in the range from 1 Hz to 1 MHz. Initial measurements were carried out in Si-SiO2 capacitors in order to test the system and in GaAs MIS capacitors abricated using liquid anodization.

Workload-Adaptive Human Interface to Aid Robust Decision Making in Human-System Interface. Year 1 Report

DTIC Science & Technology

2014-04-30

performance is to create a computational system to mimic human game-play patterns. The objective of this study is to see to what extent we can...estimates as a function of task load. We conducted a pair of studies towards’ this end. In a first study , described in detail in Appendix D...could inform a system as to the relative workload of a user. In a second study , described in detail in Appendix E, participants were exposed to a 40

High thermal conductivity in electrostatically engineered amorphous polymers

PubMed Central

Shanker, Apoorv; Li, Chen; Kim, Gun-Ho; Gidley, David; Pipe, Kevin P.; Kim, Jinsang

2017-01-01

High thermal conductivity is critical for many applications of polymers (for example, packaging of light-emitting diodes), in which heat must be dissipated efficiently to maintain the functionality and reliability of a system. Whereas uniaxially extended chain morphology has been shown to significantly enhance thermal conductivity in individual polymer chains and fibers, bulk polymers with coiled and entangled chains have low thermal conductivities (0.1 to 0.4 W m−1 K−1). We demonstrate that systematic ionization of a weak anionic polyelectrolyte, polyacrylic acid (PAA), resulting in extended and stiffened polymer chains with superior packing, can significantly enhance its thermal conductivity. Cross-plane thermal conductivity in spin-cast amorphous films steadily grows with PAA degree of ionization, reaching up to ~1.2 W m−1 K−1, which is on par with that of glass and about six times higher than that of most amorphous polymers, suggesting a new unexplored molecular engineering strategy to achieve high thermal conductivities in amorphous bulk polymers. PMID:28782022

Conductance fluctuations in high mobility monolayer graphene: Nonergodicity, lack of determinism and chaotic behavior

PubMed Central

da Cunha, C. R.; Mineharu, M.; Matsunaga, M.; Matsumoto, N.; Chuang, C.; Ochiai, Y.; Kim, G.-H.; Watanabe, K.; Taniguchi, T.; Ferry, D. K.; Aoki, N.

2016-01-01

We have fabricated a high mobility device, composed of a monolayer graphene flake sandwiched between two sheets of hexagonal boron nitride. Conductance fluctuations as functions of a back gate voltage and magnetic field were obtained to check for ergodicity. Non-linear dynamics concepts were used to study the nature of these fluctuations. The distribution of eigenvalues was estimated from the conductance fluctuations with Gaussian kernels and it indicates that the carrier motion is chaotic at low temperatures. We argue that a two-phase dynamical fluid model best describes the transport in this system and can be used to explain the violation of the so-called ergodic hypothesis found in graphene. PMID:27609184

Conductance fluctuations in high mobility monolayer graphene: Nonergodicity, lack of determinism and chaotic behavior.

PubMed

da Cunha, C R; Mineharu, M; Matsunaga, M; Matsumoto, N; Chuang, C; Ochiai, Y; Kim, G-H; Watanabe, K; Taniguchi, T; Ferry, D K; Aoki, N

2016-09-09

We have fabricated a high mobility device, composed of a monolayer graphene flake sandwiched between two sheets of hexagonal boron nitride. Conductance fluctuations as functions of a back gate voltage and magnetic field were obtained to check for ergodicity. Non-linear dynamics concepts were used to study the nature of these fluctuations. The distribution of eigenvalues was estimated from the conductance fluctuations with Gaussian kernels and it indicates that the carrier motion is chaotic at low temperatures. We argue that a two-phase dynamical fluid model best describes the transport in this system and can be used to explain the violation of the so-called ergodic hypothesis found in graphene.

Decoding leaf hydraulics with a spatially explicit model: principles of venation architecture and implications for its evolution.

PubMed

McKown, Athena D; Cochard, Hervé; Sack, Lawren

2010-04-01

Leaf venation architecture is tremendously diverse across plant species. Understanding the hydraulic functions of given venation traits can clarify the organization of the vascular system and its adaptation to environment. Using a spatially explicit model (the program K_leaf), we subjected realistic simulated leaves to modifications and calculated the impacts on xylem and leaf hydraulic conductance (K(x) and K(leaf), respectively), important traits in determining photosynthesis and growth. We tested the sensitivity of leaves to altered vein order conductivities (1) in the absence or (2) presence of hierarchical vein architecture, (3) to major vein tapering, and (4) to modification of vein densities (length/leaf area). The K(x) and K(leaf) increased with individual vein order conductivities and densities; for hierarchical venation systems, the greatest impact was from increases in vein conductivity for lower vein orders and increases in density for higher vein orders. Individual vein order conductivities were colimiting of K(x) and K(leaf), as were their densities, but the effects of vein conductivities and densities were orthogonal. Both vein hierarchy and vein tapering increased K(x) relative to xylem construction cost. These results highlight the important consequences of venation traits for the economics, ecology, and evolution of plant transport capacity.

Generation of conductivity through transfer charge properties, for polyesters and polyamides with characteristic functional groups

NASA Astrophysics Data System (ADS)

Gonzalez, Carmen; Tagle, Luis Hernan; Terraza, Claudio A.; Barriga, Andres; Cabrera, A. L.; Volkmann, Ulrich G.

2011-03-01

Electro-optic properties of σ -conjugated polymers, as polysilylene; are associated with electron conjugation in the silicon atom, which allows a significant delocalization of electrons along of the chain. Thus, the conductivity is intimately connected to the mobility of charge carriers, which in turn depends on the structure and morphology of the system. We report the characterization of polyesters (PEFs) and polyamides (PAFs). Film thicknesses were obtained by ellipsometry. The vibration frequencies of the groups were determined by FT-IR and corroborated by Raman spectroscopy. Structural information was obtained from X-Ray diffraction (XRD). The structural and surface morphology were studied by scanning electron microscope (SEM). Electrical conductivity of the polymers was measured before and after exposure to iodine vapor, for films of different thicknesses. Morphological differentiation was studied by energy dispersive microscopy (EDX), showing a regular distribution of iodine within the polymer. Preliminary conductivity measurements showed adverse effects when oxidation of the polymer films is induced These effects are related to a certain grade of disorder within the system

Mechanisms underlying the cardiac pacemaker: the role of SK4 calcium-activated potassium channels

PubMed Central

Weisbrod, David; Khun, Shiraz Haron; Bueno, Hanna; Peretz, Asher; Attali, Bernard

2016-01-01

The proper expression and function of the cardiac pacemaker is a critical feature of heart physiology. The sinoatrial node (SAN) in human right atrium generates an electrical stimulation approximately 70 times per minute, which propagates from a conductive network to the myocardium leading to chamber contractions during the systoles. Although the SAN and other nodal conductive structures were identified more than a century ago, the mechanisms involved in the generation of cardiac automaticity remain highly debated. In this short review, we survey the current data related to the development of the human cardiac conduction system and the various mechanisms that have been proposed to underlie the pacemaker activity. We also present the human embryonic stem cell-derived cardiomyocyte system, which is used as a model for studying the pacemaker. Finally, we describe our latest characterization of the previously unrecognized role of the SK4 Ca2+-activated K+ channel conductance in pacemaker cells. By exquisitely balancing the inward currents during the diastolic depolarization, the SK4 channels appear to play a crucial role in human cardiac automaticity. PMID:26725737

Mechanisms underlying the cardiac pacemaker: the role of SK4 calcium-activated potassium channels.

PubMed

Weisbrod, David; Khun, Shiraz Haron; Bueno, Hanna; Peretz, Asher; Attali, Bernard

2016-01-01

The proper expression and function of the cardiac pacemaker is a critical feature of heart physiology. The sinoatrial node (SAN) in human right atrium generates an electrical stimulation approximately 70 times per minute, which propagates from a conductive network to the myocardium leading to chamber contractions during the systoles. Although the SAN and other nodal conductive structures were identified more than a century ago, the mechanisms involved in the generation of cardiac automaticity remain highly debated. In this short review, we survey the current data related to the development of the human cardiac conduction system and the various mechanisms that have been proposed to underlie the pacemaker activity. We also present the human embryonic stem cell-derived cardiomyocyte system, which is used as a model for studying the pacemaker. Finally, we describe our latest characterization of the previously unrecognized role of the SK4 Ca(2+)-activated K(+) channel conductance in pacemaker cells. By exquisitely balancing the inward currents during the diastolic depolarization, the SK4 channels appear to play a crucial role in human cardiac automaticity.

The Development and Testing of a Statewide Multilevel Curriculum Management System for Georgia Vocational Education Programs. Curriculum Management Handbook for Vocational Administrators in Comprehensive High Schools, Post-Secondary Area Vocational-Technical Schools and Community College Vocational Programs.

ERIC Educational Resources Information Center

Scott, Paul; Moye, Mike

Developed to assist the building-level administrator in implementing a curriculum management system, this handbook considers two of five duties the vocational administrator must perform to meet the obligations of curriculum management: (1) performing curriculum management functions for the vocational program and (2) implementing and conducting an…

Boosting electrical conductivity in a gel-derived material by nanostructuring with trace carbon nanotubes

NASA Astrophysics Data System (ADS)

Canevet, David; Pérez Del Pino, Angel; Amabilino, David B.; Sallé, Marc

2011-07-01

An organogelator with two distinct π-functional units is able to incorporate carbon nanotubes into its mesh of fibres in the gel state. The morphology of the material derived from this nanocomposite after evaporation of the solvent is a complex mesh of fibres which is clearly different from the pure gelator. This feature indicates a role of the nanotubes in assisting the formation of a fibre structure in the gel thanks to their interaction with the pyrene units in the organogelator. The nanocomposite conducts electricity once the p-type gelator is doped with iodine vapour. The change in morphology caused by the carbon material increases the conductivity of the material compared with the purely organic conducting system. It is remarkable that this improvement in the physical property is caused by an extremely small proportion of the carbon material (only present at a ratio of 0.1% w/w). The practically unique properties of TTF unit allow measurements with both doped and undoped materials with conducting atomic force microscopy which have demonstrated that the carbon nanotubes are not directly responsible for the increased conductivity.An organogelator with two distinct π-functional units is able to incorporate carbon nanotubes into its mesh of fibres in the gel state. The morphology of the material derived from this nanocomposite after evaporation of the solvent is a complex mesh of fibres which is clearly different from the pure gelator. This feature indicates a role of the nanotubes in assisting the formation of a fibre structure in the gel thanks to their interaction with the pyrene units in the organogelator. The nanocomposite conducts electricity once the p-type gelator is doped with iodine vapour. The change in morphology caused by the carbon material increases the conductivity of the material compared with the purely organic conducting system. It is remarkable that this improvement in the physical property is caused by an extremely small proportion of the carbon material (only present at a ratio of 0.1% w/w). The practically unique properties of TTF unit allow measurements with both doped and undoped materials with conducting atomic force microscopy which have demonstrated that the carbon nanotubes are not directly responsible for the increased conductivity. Electronic supplementary information (ESI) available: Details concerning the preparation of 1-SWCNTs composite. See DOI: 10.1039/c1nr10235d

Figure of merit studies of beam power concepts for advanced space exploration

NASA Technical Reports Server (NTRS)

Miller, Gabriel; Kadiramangalam, Murali N.

1990-01-01

Surface to surface, millimeter wavelength beam power systems for power transmission on the lunar base were investigated. Qualitative/quantitative analyses and technology assessment of 35, 110 and 140 GHz beam power systems were conducted. System characteristics including mass, stowage volume, cost and efficiency as a function of range and power level were calculated. A simple figure of merit analysis indicates that the 35 GHz system would be the preferred choice for lunar base applications, followed closely by the 110 GHz system. System parameters of a 35 GHz beam power system appropriate for power transmission on a recent lunar base concept studied by NASA-Johnson and the necessary deployment sequence are suggested.

A system identification technique based on the random decrement signatures. Part 1: Theory and simulation

NASA Technical Reports Server (NTRS)

Bedewi, Nabih E.; Yang, Jackson C. S.

1987-01-01

Identification of the system parameters of a randomly excited structure may be treated using a variety of statistical techniques. Of all these techniques, the Random Decrement is unique in that it provides the homogeneous component of the system response. Using this quality, a system identification technique was developed based on a least-squares fit of the signatures to estimate the mass, damping, and stiffness matrices of a linear randomly excited system. The mathematics of the technique is presented in addition to the results of computer simulations conducted to demonstrate the prediction of the response of the system and the random forcing function initially introduced to excite the system.

Spacecraft systems engineering: An introduction to the process at GSFC

NASA Technical Reports Server (NTRS)

Fragomeni, Tony; Ryschkewitsch, Michael G.

1993-01-01

The main objective in systems engineering is to devise a coherent total system design capable of achieving the stated requirements. Requirements should be rigid. However, they should be continuously challenged, rechallenged and/or validated. The systems engineer must specify every requirement in order to design, document, implement and conduct the mission. Each and every requirement must be logically considered, traceable and evaluated through various analysis and trade studies in a total systems design. Margins must be determined to be realistic as well as adequate. The systems engineer must also continuously close the loop and verify system performance against the requirements. The fundamental role of the systems engineer, however, is to engineer, not manage. Yet, in large, complex missions, where more than one systems engineer is required, someone needs to manage the systems engineers, and we call them 'systems managers.' Systems engineering management is an overview function which plans, guides, monitors and controls the technical execution of a project as implemented by the systems engineers. As the project moves on through Phases A and B into Phase C/D, the systems engineering tasks become a small portion of the total effort. The systems management role increases since discipline subsystem engineers are conducting analyses and reviewing test data for final review and acceptance by the systems managers.

A digital computer simulation and study of a direct-energy-transfer power-conditioning system

NASA Technical Reports Server (NTRS)

Burns, W. W., III; Owen, H. A., Jr.; Wilson, T. G.; Rodriguez, G. E.; Paulkovich, J.

1975-01-01

An investigation of the behavior of the power-conditioning system as a whole is a necessity to ensure the integrity of the aggregate system in the case of space applications. An approach for conducting such an investigation is considered. A description is given of the application of a general digital analog simulator program to the study of an aggregate power-conditioning system which is being developed for use on the International Ultraviolet Explorer spacecraft. The function of the direct energy transfer system studied involves a coupling of a solar array through a main distribution bus to the spacecraft electrical loads.

Model-OA wind turbine generator - Failure modes and effects analysis

NASA Technical Reports Server (NTRS)

Klein, William E.; Lali, Vincent R.

1990-01-01

The results failure modes and effects analysis (FMEA) conducted for wind-turbine generators are presented. The FMEA was performed for the functional modes of each system, subsystem, or component. The single-point failures were eliminated for most of the systems. The blade system was the only exception. The qualitative probability of a blade separating was estimated at level D-remote. Many changes were made to the hardware as a result of this analysis. The most significant change was the addition of the safety system. Operational experience and need to improve machine availability have resulted in subsequent changes to the various systems, which are also reflected in this FMEA.

Model 0A wind turbine generator FMEA

NASA Technical Reports Server (NTRS)

Klein, William E.; Lalli, Vincent R.

1989-01-01

The results of Failure Modes and Effects Analysis (FMEA) conducted for the Wind Turbine Generators are presented. The FMEA was performed for the functional modes of each system, subsystem, or component. The single-point failures were eliminated for most of the systems. The blade system was the only exception. The qualitative probability of a blade separating was estimated at level D-remote. Many changes were made to the hardware as a result of this analysis. The most significant change was the addition of the safety system. Operational experience and need to improve machine availability have resulted in subsequent changes to the various systems which are also reflected in this FMEA.

Human System Integration: Regulatory Analysis

NASA Technical Reports Server (NTRS)

2005-01-01

This document was intended as an input to the Access 5 Policy Integrated Product team. Using a Human System Integration (HIS) perspective, a regulatory analyses of the FARS (specifically Part 91), the Airman s Information Manual (AIM) and the FAA Controllers Handbook (7110.65) was conducted as part of a front-end approach needed to derive HSI requirements for Unmanned Aircraft Systems (UAS) operations in the National Airspace System above FL430. The review of the above aviation reference materials yielded eighty-four functions determined to be necessary or highly desirable for flight within the Air Traffic Management System. They include categories for Flight, Communications, Navigation, Surveillance, and Hazard Avoidance.

Overview of the Space Launch System Transonic Buffet Environment Test Program

NASA Technical Reports Server (NTRS)

Piatak, David J.; Sekula, Martin K.; Rausch, Russ D.; Florance, James R.; Ivanco, Thomas G.

2015-01-01

Fluctuating aerodynamic loads are a significant concern for the structural design of a launch vehicle, particularly while traversing the transonic flight environment. At these trajectory conditions, unsteady aerodynamic pressures can excite the vehicle dynamic modes of vibration and result in high structural bending moments and vibratory environments. To ensure that vehicle structural components and subsystems possess adequate strength, stress, and fatigue margins in the presence of buffet and other environments, buffet forcing functions are required to conduct the coupled load analysis of the launch vehicle. The accepted method to obtain these buffet forcing functions is to perform wind-tunnel testing of a rigid model that is heavily instrumented with unsteady pressure transducers designed to measure the buffet environment within the desired frequency range. Two wind-tunnel tests of a 3 percent scale rigid buffet model have been conducted at the Langley Research Center Transonic Dynamics Tunnel (TDT) as part of the Space Launch System (SLS) buffet test program. The SLS buffet models have been instrumented with as many as 472 unsteady pressure transducers to resolve the buffet forcing functions of this multi-body configuration through integration of the individual pressure time histories. This paper will discuss test program development, instrumentation, data acquisition, test implementation, data analysis techniques, and several methods explored to mitigate high buffet environment encountered during the test program. Preliminary buffet environments will be presented and compared using normalized sectional buffet forcing function root-meansquared levels along the vehicle centerline.

Effect of Eutectic Concentration on Conductivity in PEO:LiX Based Solid Polymer Electrolytes

NASA Astrophysics Data System (ADS)

Zhan, Pengfei; Ganapatibhotla, Lalitha; Maranas, Janna

Polyethylene oxide (PEO) and lithium salt based solid polymer electrolytes (SPEs) have been widely proposed as a substitution for the liquid electrolyte in Li-ion batteries. As salt concentration varies, these systems demonstrate rich phase behavior. Conductivity as a function of salt concentration has been measured for decades and various concentration dependences have been observed. A PEO:LiX mixture can have one or two conductivity maximums, while some mixtures with salt of high ionic strength will have higher conductivity as the salt concentration decrease. The factors that affect the conductivity are specific for each sample. The universal factor that affects conductivity is still not clear. In this work, we measured the conductivity of a series of PEO:LiX mixtures and statistical analysis shows conductivity is affected by the concentration difference from the eutectic concentration (Δc). The correlation with Δc is stronger than the correlation with glass transition temperature. We believe that at the eutectic concentration, during the solidification process, unique structures can form which aid conduction. Currently at Dow Chemical.