Spatial Distribution of Lead Iodide and Local Passivation on Organo-Lead Halide Perovskite.

PubMed

Chen, Sheng; Wen, Xiaoming; Yun, Jae S; Huang, Shujuan; Green, Martin; Jeon, Nam Joong; Yang, Woon Seok; Noh, Jun Hong; Seo, Jangwon; Seok, Sang Il; Ho-Baillie, Anita

2017-02-22

We identify nanoscale spatial distribution of PbI 2 on the (FAPbI 3 ) 0.85 (MAPbBr 3 ) 0.15 perovskite thin film and investigate the local passivation effect using confocal based optical microscopy of steady state and time-resolved photoluminescence (PL). Different from a typical scanning electron microscope (SEM) morphology study, confocal based PL spectroscopy and microscopy allow researchers to map the morphologies of both perovskite and PbI 2 grains simultaneously, by selectively detecting their characteristic fluorescent bands using band-pass filters. In this work, we compare the perovskite samples without and with excess PbI 2 incorporation and unambiguously reveal PbI 2 distribution for the PbI 2 -rich sample. In addition, using the nanoscale time-resolved PL technique we show that the PbI 2 -rich regions exhibit longer lifetime due to suppressed defect trapping, compared to the PbI 2 -poor regions. The measurement on the PbI 2 -rich sample indicates that the passivation effect of PbI 2 in perovskite film is effective, especially in localized regions. Hence, this finding is important for further improvement of the solar cells by considering the strategy of excess PbI 2 incorporation.

Passive monitoring and localization of marine mammals in open ocean environments using widely spaced bottom mounted hydrophones

NASA Astrophysics Data System (ADS)

Jarvis, Susan; Moretti, David; Morrissey, Ronald; Dimarzio, Nancy

2003-10-01

The Marine Mammal Monitoring on Navy Ranges (M3R) project has developed a toolset for passive detection and localization of marine mammals using the existing infrastructure of Navy's undersea ranges. The Office of Naval Research funded the M3R project as part of the Navy's effort to determine the effects of acoustic and other emissions on marine mammals and threatened/endangered species. A necessary first step in this effort is the creation of a baseline of behavior, which requires long-term monitoring of marine mammals. Such monitoring, in turn, requires the ability to detect and localize the animals. This paper will present the passive acoustic monitoring and localization tools developed under M3R. It will also present results of the deployment of the M3R tools at the Atlantic Undersea Test and Evaluation Center (AUTEC), Andros Island, Bahamas from June through November 2003. Finally, it will discuss current work to improve automated species classification.

Methodology for the passive control of orbital inclination and mean local time to meet sun-synchronous orbit requirements

NASA Technical Reports Server (NTRS)

Folta, David; Kraft, Lauri

1992-01-01

The mean local time (MLT) of equatorial crossing of a sun-synchronous Earth-observing spacecraft orbit drifts with inclination; therefore, in order to maintain the MLT, the inclination must be controlled. Inclination may be maintained actively by costly out-of-plane maneuvers or passively by using the perturbing forces due to the sun and moon. This paper examines the passive control approach using the Earth Observing System (EOS) as a basis for the discussion. Applications to Landsat and National Oceanic and Atmospheric Administration (NOAA) spacecraft are presented for comparison. This technique is especially beneficial to spacecraft lacking propulsion systems. The results indicate that passive inclination control appears to be the preferable maintenance method when spacecraft weight restrictions, operational considerations, and scientific requirements apply.

Passivation Behavior of Ultrafine-Grained Pure Copper Fabricated by Accumulative Roll Bonding (ARB) Process

NASA Astrophysics Data System (ADS)

Fattah-alhosseini, Arash; Imantalab, Omid

2016-01-01

In this study, passivation behavior of ultrafine-grained (UFG) pure copper fabricated by ARB process in 0.01 M borax solution has been investigated. Before any electrochemical measurements, evaluation of microstructure was obtained by transmission electron microscopy (TEM). TEM observations revealed that with increasing the number of ARB passes, the grain size of specimens decrease. Also, TEM images showed that UFGs with average size of below 100 nm appeared after 7 passes of ARB. To investigate the passivation behavior of the specimens, electrochemical impedance spectroscopy (EIS) and Mott-Schottky analysis was carried out. For this purpose, three potentials within the passive region were chosen for potentiostatic passive film growth. EIS results showed that both passive film and charge-transfer resistance increases with increasing the number of ARB passes. Moreover, Mott-Schottky analysis revealed that with increasing the number of ARB passes, the acceptor density of the passive films decreased. In conclusion, increasing the number of ARB passes offers better conditions for forming the passive films with higher protection behavior, due to the growth of a much thicker and less defective films.

Improved passive optical network architectures to support local area network emulation and protection

NASA Astrophysics Data System (ADS)

Wong, Elaine; Nadarajah, Nishaanthan; Chae, Chang-Joon; Nirmalathas, Ampalavanapillai; Attygalle, Sanjeewa M.

2006-01-01

We describe two optical layer schemes which simultaneously facilitate local area network emulation and automatic protection switching against distribution fiber breaks in passive optical networks. One scheme employs a narrowband fiber Bragg grating placed close to the star coupler in the feeder fiber of the passive optical network, while the other uses an additional short length distribution fiber from the star coupler to each customer for the redirection of the customer traffic. Both schemes use RF subcarrier multiplexed transmission for intercommunication between customers in conjunction with upstream access to the central office at baseband. Failure detection and automatic protection switching are performed independently by each optical network unit that is located at the customer premises in a distributed manner. The restoration of traffic transported between the central office and an optical network unit in the event of the distribution fiber break is performed by interconnecting adjacent optical network units and carrying out signal transmissions via an independent but interconnected optical network unit. Such a protection mechanism enables multiple adjacent optical network units to be simultaneously protected by a single optical network unit utilizing its maximum available bandwidth. We experimentally verify the feasibility of both schemes with 1.25 Gb/s upstream baseband transmission to the central office and 155 Mb/s local area network data transmission on a RF subcarrier frequency. The experimental results obtained from both schemes are compared, and the power budgets are calculated to analyze the scalability of each scheme.

Dual Electrolytic Plasma Processing for Steel Surface Cleaning and Passivation

NASA Astrophysics Data System (ADS)

Yang, L.; Zhang, P.; Shi, J.; Liang, J.; Tian, W. B.; Zhang, Y. M.; Sun, Z. M.

2017-10-01

To remove the rust on rebars and passivate the fresh surfaces, electrodes reversing electrolytic plasma processing (EPP) was proposed and conducted in a 10 wt.% Na2CO3 aqueous solution. The morphology and the composition of the surface were investigated by SEM and XPS. Experimental results show that the rust on the surface was removed effectively by cathode EPP, and a passive film containing Cr2O3 was achieved by the succeeding anode EPP treatment, by a simple operation of reversing the bias. The corrosion resistance was evaluated in a 3.5 wt.% NaCl aqueous solution using an electrochemical workstation. In comparison, the corrosion resistance was improved by the succeeding anode EPP treatment, which is evidenced by a positive shift of the open-circuit potential, an increase in the electrochemical impedance representing the inner layer by 76.8% and the decrease in the corrosion current density by 49.6%. This is an effective and environment-friendly technique to clean and passivate rebars and similar steel materials.

Real-time image processing for passive mmW imagery

NASA Astrophysics Data System (ADS)

Kozacik, Stephen; Paolini, Aaron; Bonnett, James; Harrity, Charles; Mackrides, Daniel; Dillon, Thomas E.; Martin, Richard D.; Schuetz, Christopher A.; Kelmelis, Eric; Prather, Dennis W.

2015-05-01

The transmission characteristics of millimeter waves (mmWs) make them suitable for many applications in defense and security, from airport preflight scanning to penetrating degraded visual environments such as brownout or heavy fog. While the cold sky provides sufficient illumination for these images to be taken passively in outdoor scenarios, this utility comes at a cost; the diffraction limit of the longer wavelengths involved leads to lower resolution imagery compared to the visible or IR regimes, and the low power levels inherent to passive imagery allow the data to be more easily degraded by noise. Recent techniques leveraging optical upconversion have shown significant promise, but are still subject to fundamental limits in resolution and signal-to-noise ratio. To address these issues we have applied techniques developed for visible and IR imagery to decrease noise and increase resolution in mmW imagery. We have developed these techniques into fieldable software, making use of GPU platforms for real-time operation of computationally complex image processing algorithms. We present data from a passive, 77 GHz, distributed aperture, video-rate imaging platform captured during field tests at full video rate. These videos demonstrate the increase in situational awareness that can be gained through applying computational techniques in real-time without needing changes in detection hardware.

Fluorine incorporation in solution-processed poly-siloxane passivation for highly reliable a-InGaZnO thin-film transistors

NASA Astrophysics Data System (ADS)

Yoshida, Naofumi; Bermundo, Juan Paolo; Ishikawa, Yasuaki; Nonaka, Toshiaki; Taniguchi, Katsuto; Uraoka, Yukiharu

2018-03-01

We investigated a fluorine-containing polysiloxane (Poly-SX) passivation layer fabricated by solution process for amorphous InGaZnO (a-IGZO) thin-film transistors (TFT). This passivation layer greatly improved the stability of the a-IGZO device even after being subjected to positive bias stress (PBS) and negative bias stress (NBS). The mobility (µ) of TFTs passivated by fluorine-containing Poly-SX increased by 31%-56% (10.50-12.54 cm2 V-1 s-1) compared with TFTs passivated by non-fluorinated Poly-SX (8.04 cm2 V-1 s-1). Increasing the amount of fluorine additives led to a higher µ in passivated TFTs. Aside from enhancing the performance, these passivation layers could increase the reliability of a-IGZO TFTs under PBS and NBS with a minimal threshold voltage shift (ΔV th) of up to  +0.2 V and  -0.1 V, respectively. Additionally, all TFTs passivated by the fluorinated passivation materials did not exhibit a hump effect after NBS. We also showed that fluorinated photosensitive Poly-SX, which can be fabricated without any dry etching process, had an effective passivation property. In this report, we demonstrated the photolithography of Poly-SX, and electrical properties of Poly-SX passivated TFTs, and analyzed the state of the a-IGZO layer to show the large potential of Poly-SX as an effective solution-processed passivation material.

Workshop on the Detection, Classification, Localization and Density Estimation of Marine Mammals Using Passive Acoustics - 2015

DTIC Science & Technology

2015-09-30

together the research community working on marine mammal acoustics to discuss detection, classification, localization and density estimation methods...and Density Estimation of Marine Mammals Using Passive Acoustics - 2015 John A. Hildebrand Scripps Institution of Oceanography UCSD La Jolla...dclde LONG-TERM GOALS The goal of this project was to bring together the community of researchers working on methods for detection

Passive Sensor Integration for Vehicle Self-Localization in Urban Traffic Environment †

PubMed Central

Gu, Yanlei; Hsu, Li-Ta; Kamijo, Shunsuke

2015-01-01

This research proposes an accurate vehicular positioning system which can achieve lane-level performance in urban canyons. Multiple passive sensors, which include Global Navigation Satellite System (GNSS) receivers, onboard cameras and inertial sensors, are integrated in the proposed system. As the main source for the localization, the GNSS technique suffers from Non-Line-Of-Sight (NLOS) propagation and multipath effects in urban canyons. This paper proposes to employ a novel GNSS positioning technique in the integration. The employed GNSS technique reduces the multipath and NLOS effects by using the 3D building map. In addition, the inertial sensor can describe the vehicle motion, but has a drift problem as time increases. This paper develops vision-based lane detection, which is firstly used for controlling the drift of the inertial sensor. Moreover, the lane keeping and changing behaviors are extracted from the lane detection function, and further reduce the lateral positioning error in the proposed localization system. We evaluate the integrated localization system in the challenging city urban scenario. The experiments demonstrate the proposed method has sub-meter accuracy with respect to mean positioning error. PMID:26633420

Apparatus and process for passivating an SRF cavity

DOEpatents

Myneni, Ganapati Rao; Wallace, John P

2014-12-02

An apparatus and process for the production of a niobium cavity exhibiting high quality factors at high gradients is provided. The apparatus comprises a first chamber positioned within a second chamber, an RF generator and vacuum pumping systems. The process comprises placing the niobium cavity in a first chamber of the apparatus; thermally treating the cavity by high temperature in the first chamber while maintaining high vacuum in the first and second chambers; and applying a passivating thin film layer to a surface of the cavity in the presence of a gaseous mixture and an RF field. Further a niobium cavity exhibiting high quality factors at high gradients produced by the method of the invention is provided.

Enhanced Passive and Active Processing of Syllables in Musician Children

ERIC Educational Resources Information Center

Chobert, Julie; Marie, Celine; Francois, Clement; Schon, Daniele; Besson, Mireille

2011-01-01

The aim of this study was to examine the influence of musical expertise in 9-year-old children on passive (as reflected by MMN) and active (as reflected by discrimination accuracy) processing of speech sounds. Musician and nonmusician children were presented with a sequence of syllables that included standards and deviants in vowel frequency,…

Effect of Local Vibration and Passive Exercise on the Hormones and Neurotransmitters of Hypothalamic-Pituitary-Adrenal Axis in Hindlimb Unloading Rats

NASA Astrophysics Data System (ADS)

Luan, Huiqin; Huang, Yunfei; Li, Jian; Sun, Lianwen; Fan, Yubo

2018-04-01

Astronauts are severely affected by spaceflight-induced bone loss. Mechanical stimulation through exercise inhibits bone resorption and improves bone formation. Exercise and vibration can prevent the degeneration of the musculoskeletal system in tail-suspended rats, and long-term exercise stress will affect endocrine and immune systems that are prone to fatigue. However, the mechanisms through which exercise and vibration affect the endocrine system remain unknown. This study mainly aimed to investigate the changes in the contents of endocrine axis-related hormones and the effects of local vibration and passive exercise on hypothalamic-pituitary-adrenal (HPA) axis-related hormones in tail-suspended rats. A total of 32 Sprague-Dawley rats were randomly distributed into four groups (n = 8 per group): tail suspension (TS), TS + 35Hz vibration, TS + passive exercise, and control. The rats were placed on a passive exercise and local vibration regimen for 21 days. On day 22 of the experiment, the contents of corticotrophin-releasing hormone, adrenocorticotropic hormone, cortisol, and 5-hydroxytryptamine in the rats were quantified with kits in accordance with the manufacturer's instructions. Histomorphometry was applied to evaluate histological changes in the hypothalamus. Results showed that 35Hz local vibration cannot cause rats to remain in a stressed state and that it might not inhibit the function of the HPA axis. Therefore, we speculate that this local vibration intensity can protect the function of the HPA axis and helps tail-suspended rats to transition from stressed to adaptive state.

Passive sampler for PM10-2.5 aerosol.

PubMed

Leith, David; Sommerlatt, Darrell; Boundy, Maryanne G

2007-03-01

This study investigates the use of a small passive sampler for aerosol particles to determine particulate matter (PM)10-2.5 concentrations in outdoor air. The passive sampler collects particles by gravity, diffusion, and convective diffusion onto a glass coverslip that is then examined with an optical microscope; digital images are processed with free software and the resultant PM10-2.5 concentrations determined. Both the samplers and the analyses are relatively inexpensive. Passive samplers were collocated with Federal Reference Method (FRM) samplers in Chapel Hill, NC; Phoenix, AZ; and Birmingham, AL; for periods from 5 to 15 days. Particles consisted primarily of inorganic dusts at some sites and a mix of industrial and inorganic materials at other sites. Measured concentrations ranged from < 10 microg/m3 to approximately 40 microg/m3. Overall, PM10-2.5 concentrations measured with the passive samplers were within approximately 1 standard deviation of concentrations measured with the FRM samplers. Concentrations determined with passive samplers depend on assumptions about particle density and shape factors and may also depend somewhat on local wind speed and turbulence; accurate values for these parameters may not be known. The degree of agreement between passive and FRM concentrations measured here suggests that passive measurements may not be overly dependent on accurate knowledge of these parameters.

Lexically Specific Knowledge and Individual Differences in Adult Native Speakers' Processing of the English Passive

ERIC Educational Resources Information Center

Street, James A.; Dabrowska, Ewa

2014-01-01

This article provides experimental evidence for the role of lexically specific representations in the processing of passive sentences and considerable education-related differences in comprehension of the passive construction. The experiment measured response time and decision accuracy of participants with high and low academic attainment using an…

Dry etching, surface passivation and capping processes for antimonide based photodetectors

NASA Astrophysics Data System (ADS)

Dutta, Partha; Langer, Jeffery; Bhagwat, Vinay; Juneja, Jasbir

2005-05-01

III-V antimonide based devices suffer from leakage currents. Surface passivation and subsequent capping of the surfaces are absolutely essential for any practical applicability of antimonide based devices. The quest for a suitable surface passivation technology is still on. In this paper, we will present some of the promising recent developments in this area based on dry etching of GaSb based homojunction photodiodes structures followed by various passivation and capping schemes. We have developed a damage-free, universal dry etching recipe based on unique ratios of Cl2/BCl3/CH4/Ar/H2 in ECR plasma. This novel dry plasma process etches all III-V compounds at different rates with minimal damage to the side walls. In GaSb based photodiodes, an order of magnitude lower leakage current, improved ideality factor and higher responsivity has been demonstrated using this recipe compared to widely used Cl2/Ar and wet chemical etch recipes. The dynamic zero bias resistance-area product of the Cl2/BCl3/CH4/Ar/H2 etched diodes (830 Ω cm2) is higher than the Cl2/Ar (300 Ω cm2) and wet etched (330 Ω cm2) diodes. Ammonium sulfide has been known to passivate surfaces of III-V compounds. In GaSb photodiodes, the leakage current density reduces by a factor of 3 upon sulfur passivation using ammonium sulfide. However, device performance degrades over a period of time in the absence of any capping or protective layer. Silicon Nitride has been used as a cap layer by various researchers. We have found that by using silicon nitride caps, the devices exhibit higher leakage than unpassivated devices probably due to plasma damage during SiNx deposition. We have experimented with various polymers for capping material. It has been observed that ammonium sulfide passivation when combined with parylene capping layer (150 Å), devices retain their improved performance for over 4 months.

Antireflection/Passivation Step For Silicon Cell

NASA Technical Reports Server (NTRS)

Crotty, Gerald T.; Kachare, Akaram H.; Daud, Taher

1988-01-01

New process excludes usual silicon oxide passivation. Changes in principal electrical parameters during two kinds of processing suggest antireflection treatment almost as effective as oxide treatment in passivating cells. Does so without disadvantages of SiOx passivation.

Harmonic reduction by using single-tuned passive filter in plastic processing industry

NASA Astrophysics Data System (ADS)

Fahmi, M. I.; Baafai, U.; Hazmi, A.; Nasution, T. H.

2018-02-01

The using of non-linear loads generated by industrial machines may result inconsistent harmonics that do not reach the IEEE 519 - 1992 standards. This study discusses the use of single-tuned passive filters in reducing harmonics in the plastics processing industry. The system modeling using matlab / simulink simulation resulted in total harmonic distortion (THD) of 15.55%, can be reduced to 4.77% harmonics in accordance with IEEE 519 - 1992 standards. From the simulation results also seen that single-tuned passive filter can reduce the harmonics of the current 82.23% harmonic that wants to be reduced and also can reduce other orders harmonics between 7% to 8%.

Fabrication process for polymer PLC platforms with V-grooves for passive alignment

NASA Astrophysics Data System (ADS)

Park, Suntak; Lee, Jong-Moo; Ahn, Joon Tae; Baek, Yong-Soon

2005-12-01

A method for polymer planar lightwave circuit (PLC) devices fabricated on a substrate with V-grooves is developed for passive alignment of an optical fiber to a polymer waveguide. In order to minimize thickness nonuniformity of polymer layers caused by the V-grooves, dry film resist (DFR) is used. The V-grooves are covered with the DFR before the polymer layers are spin-coated on the substrate. The DFR prevents the polymer from being filled in the V-grooves as well as from being spin-coated nonuniformly on the substrate. This process provides a simple and cost-effective fabrication method of polymer PLCs or platforms for passive alignment.

Passivation Behavior of Fe-Based Amorphous Coatings Prepared by High-Velocity Air/Oxygen Fuel Processes

NASA Astrophysics Data System (ADS)

Ma, H. R.; Li, J. W.; Chang, C. T.; Wang, X. M.; Li, R. W.

2017-12-01

Corrosion resistance and passivation behavior of Fe63Cr8Mo3.5Ni5P10B4C4Si2.5 amorphous coatings prepared by the activated combustion high-velocity air fuel (AC-HVAF) and high-velocity oxygen fuel (HVOF) processes have been studied in detail by cyclic potentiodynamic polarization, electrochemical impedance spectroscopy, cathodic polarization and Mott-Schottky approach. The AC-HVAF coating shows higher corrosion resistance than the HVOF coating in 3.5 wt.% NaCl solution, as evidenced by its lower corrosion current density and passive current density. It is found that the superior corrosion resistance of the AC-HVAF coating is attributed to the enhanced formation of a dense passive film with less defective structure, higher pitting resistance and passivity stability, as well as stronger repassivity.

Dynamics of temporally localized states in passively mode-locked semiconductor lasers

NASA Astrophysics Data System (ADS)

Schelte, C.; Javaloyes, J.; Gurevich, S. V.

2018-05-01

We study the emergence and the stability of temporally localized structures in the output of a semiconductor laser passively mode locked by a saturable absorber in the long-cavity regime. For large yet realistic values of the linewidth enhancement factor, we disclose the existence of secondary dynamical instabilities where the pulses develop regular and subsequent irregular temporal oscillations. By a detailed bifurcation analysis we show that additional solution branches that consist of multipulse (molecules) solutions exist. We demonstrate that the various solution curves for the single and multipeak pulses can splice and intersect each other via transcritical bifurcations, leading to a complex web of solutions. Our analysis is based on a generic model of mode locking that consists of a time-delayed dynamical system, but also on a much more numerically efficient, yet approximate, partial differential equation. We compare the results of the bifurcation analysis of both models in order to assess up to which point the two approaches are equivalent. We conclude our analysis by the study of the influence of group velocity dispersion, which is only possible in the framework of the partial differential equation model, and we show that it may have a profound impact on the dynamics of the localized states.

Comparison of the effects of local cryotherapy and passive cross-body stretch on extensibility in subjects with posterior shoulder tightness.

PubMed

Park, Kyue-Nam; Kwon, Oh-Yun; Weon, Jong-Hyuck; Choung, Sung-Dae; Kim, Si-Hyun

2014-01-01

The objective was to compare the immediate effects of local cryotherapy (LC) and passive cross-body stretch on the extensibility of the posterior shoulder muscle in individuals with posterior shoulder tightness. Eighty-seven healthy subjects with a between-shoulder difference in internal rotation (IR) range of motion (ROM) greater than 10° were randomly divided into three groups: LC group, stretching group, and control group (n = 29 in each group). Subjects in the LC group received LC on infraspinatus and posterior deltoid muscles and subjects in the stretching group performed passive cross-body stretch. Stretch sensation was measured at the end range of passive IR and horizontal adduction (HA) using numerical rating scale, and the pressure pain threshold (PPT) at the infraspinatus and posterior deltoid muscles was measured using pressure algometry. Passive and active ROM of IR and HA of the glenohumeral joint were measured using an inclinometer. All measurements were performed at pre-intervention, post- intervention, and 10-min follow-up. Stretch sensation was significantly decreased and PPT was significantly increased in the LC and stretching groups at post-intervention, and these effects were maintained at 10-min follow-up, compared to the control group. Both the LC group and stretching group had a significantly greater increase in passive and active ROM of IR and HA, compared to the control group at post-intervention and 10-min follow-up. However, there were no significant differences in stretch sensation, PPT, or ROM of IR and HA between the LC group and stretching group. LC can be used to decrease the stretch sensation and increase PPT and ROM of IR and HA as much as a stretching exercise. LC could be an alternative method for increasing the restricted ROM of glenohumeral IR and HA for individuals with posterior shoulder tightness, especially for patients and sports players who have severe stretching discomfort. Key PointsLocal cryotherapy (LC) decreased the

Comparison of the Effects of Local Cryotherapy and Passive Cross-Body Stretch on Extensibility in Subjects with Posterior Shoulder Tightness

PubMed Central

Park, Kyue-nam; Kwon, Oh-yun; Weon, Jong-hyuck; Choung, Sung-dae; Kim, Si-hyun

2014-01-01

The objective was to compare the immediate effects of local cryotherapy (LC) and passive cross-body stretch on the extensibility of the posterior shoulder muscle in individuals with posterior shoulder tightness. Eighty-seven healthy subjects with a between-shoulder difference in internal rotation (IR) range of motion (ROM) greater than 10° were randomly divided into three groups: LC group, stretching group, and control group (n = 29 in each group). Subjects in the LC group received LC on infraspinatus and posterior deltoid muscles and subjects in the stretching group performed passive cross-body stretch. Stretch sensation was measured at the end range of passive IR and horizontal adduction (HA) using numerical rating scale, and the pressure pain threshold (PPT) at the infraspinatus and posterior deltoid muscles was measured using pressure algometry. Passive and active ROM of IR and HA of the glenohumeral joint were measured using an inclinometer. All measurements were performed at pre-intervention, post- intervention, and 10-min follow-up. Stretch sensation was significantly decreased and PPT was significantly increased in the LC and stretching groups at post-intervention, and these effects were maintained at 10-min follow-up, compared to the control group. Both the LC group and stretching group had a significantly greater increase in passive and active ROM of IR and HA, compared to the control group at post-intervention and 10-min follow-up. However, there were no significant differences in stretch sensation, PPT, or ROM of IR and HA between the LC group and stretching group. LC can be used to decrease the stretch sensation and increase PPT and ROM of IR and HA as much as a stretching exercise. LC could be an alternative method for increasing the restricted ROM of glenohumeral IR and HA for individuals with posterior shoulder tightness, especially for patients and sports players who have severe stretching discomfort. Key Points Local cryotherapy (LC) decreased

Petrology of exhumed mantle rocks at passive margins: ancient lithosphere and rejuvenation processes

NASA Astrophysics Data System (ADS)

Müntener, Othmar; McCarthy, Anders; Picazo, Suzanne

2014-05-01

Mantle peridotites from ocean-continent transition zones (OCT's) and ultraslow spreading ridges question the commonly held assumption of a simple link between mantle melting and MORB. 'Ancient' and partly refertilized mantle in rifts and ridges illustrates the distribution of the scale of chemical and isotopic upper mantle heterogeneity even on a local scale. Field data and petrology demonstrates that ancient, thermally undisturbed, pyroxenite-veined subcontinental mantle blobs formed parts of the ocean floor next to thinned continental crust. These heterogeneities might comprise an (ancient?) subduction component. Upwelling of partial melts that enter the conductive lithospheric mantle inevitably leads to freezing of the melt and refertilization of the lithosphere and this process might well be at the origin of the difference between magma-poor and volcanic margins. Similar heterogeneity might be created in the oceanic lithosphere, in particular at slow to ultra-slow spreading ridges where the thermal boundary layer (TBM) is thick and may be veined with metasomatic assemblages that might be recycled in subduction zones. In this presentation, we provide a summary of mantle compositions from the European realm to show that inherited mantle signatures from previous orogenies play a key role on the evolution of rift systems and on the chemical diversity of peridotites exposed along passive margins and ultra-slow spreading ridges. Particularly striking is the abundance of plagioclase peridotites in the Alpine ophiolites that are interpreted as recorders of refertilization processes related to thinning and exhumation of mantle lithosphere. Another important result over the last 20 years was the discovery of extremely refractory Nd-isotopic compositions with highly radiogenic 147Sm/144Nd which indicates that partial melting processes and Jurassic magmatism in the Western Thetys are decoupled. Although the isotopic variability might be explained by mantle heterogeneities

Passive Polarimetric Information Processing for Target Classification

NASA Astrophysics Data System (ADS)

Sadjadi, Firooz; Sadjadi, Farzad

Polarimetric sensing is an area of active research in a variety of applications. In particular, the use of polarization diversity has been shown to improve performance in automatic target detection and recognition. Within the diverse scope of polarimetric sensing, the field of passive polarimetric sensing is of particular interest. This chapter presents several new methods for gathering in formation using such passive techniques. One method extracts three-dimensional (3D) information and surface properties using one or more sensors. Another method extracts scene-specific algebraic expressions that remain unchanged under polariza tion transformations (such as along the transmission path to the sensor).

Combining Radiography and Passive Measurements for Radiological Threat Localization in Cargo

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

Miller, Erin A.; White, Timothy A.; Jarman, Kenneth D.

Detecting shielded special nuclear material (SNM) in a cargo container is a difficult problem, since shielding reduces the amount of radiation escaping the container. Radiography provides information that is complementary to that provided by passive gamma-ray detection systems: while not directly sensitive to radiological materials, radiography can reveal highly shielded regions that may mask a passive radiological signal. Combining these measurements has the potential to improve SNM detection, either through improved sensitivity or by providing a solution to the inverse problem to estimate source properties (strength and location). We present a data-fusion method that uses a radiograph to provide anmore » estimate of the radiation-transport environment for gamma rays from potential sources. This approach makes quantitative use of radiographic images without relying on image interpretation, and results in a probabilistic description of likely source locations and strengths. We present results for this method for a modeled test case of a cargo container passing through a plastic-scintillator-based radiation portal monitor and a transmission-radiography system. We find that a radiograph-based inversion scheme allows for localization of a low-noise source placed randomly within the test container to within 40 cm, compared to 70 cm for triangulation alone, while strength estimation accuracy is improved by a factor of six. Improvements are seen in regions of both high and low shielding, but are most pronounced in highly shielded regions. The approach proposed here combines transmission and emission data in a manner that has not been explored in the cargo-screening literature, advancing the ability to accurately describe a hidden source based on currently-available instrumentation.« less

Combining Radiography and Passive Measurements for Radiological Threat Localization in Cargo

NASA Astrophysics Data System (ADS)

Miller, Erin A.; White, Timothy A.; Jarman, Kenneth D.; Kouzes, Richard T.; Kulisek, Jonathan A.; Robinson, Sean M.; Wittman, Richard A.

2015-10-01

Detecting shielded special nuclear material (SNM) in a cargo container is a difficult problem, since shielding reduces the amount of radiation escaping the container. Radiography provides information that is complementary to that provided by passive gamma-ray detection systems: while not directly sensitive to radiological materials, radiography can reveal highly shielded regions that may mask a passive radiological signal. Combining these measurements has the potential to improve SNM detection, either through improved sensitivity or by providing a solution to the inverse problem to estimate source properties (strength and location). We present a data-fusion method that uses a radiograph to provide an estimate of the radiation-transport environment for gamma rays from potential sources. This approach makes quantitative use of radiographic images without relying on image interpretation, and results in a probabilistic description of likely source locations and strengths. We present results for this method for a modeled test case of a cargo container passing through a plastic-scintillator-based radiation portal monitor and a transmission-radiography system. We find that a radiograph-based inversion scheme allows for localization of a low-noise source placed randomly within the test container to within 40 cm, compared to 70 cm for triangulation alone, while strength estimation accuracy is improved by a factor of six. Improvements are seen in regions of both high and low shielding, but are most pronounced in highly shielded regions. The approach proposed here combines transmission and emission data in a manner that has not been explored in the cargo-screening literature, advancing the ability to accurately describe a hidden source based on currently-available instrumentation.

Molecular dynamics study of solid-liquid heat transfer and passive liquid flow

NASA Astrophysics Data System (ADS)

Yesudasan Daisy, Sumith

High heat flux removal is a challenging problem in boilers, electronics cooling, concentrated photovoltaic and other power conversion devices. Heat transfer by phase change is one of the most efficient mechanisms for removing heat from a solid surface. Futuristic electronic devices are expected to generate more than 1000 W/cm2 of heat. Despite the advancements in microscale and nanoscale manufacturing, the maximum passive heat flux removal has been 300 W/cm2 in pool boiling. Such limitations can be overcome by developing nanoscale thin-film evaporation based devices, which however require a better understanding of surface interactions and liquid vapor phase change process. Evaporation based passive flow is an inspiration from the transpiration process that happens in trees. If we can mimic this process and develop heat removal devices, then we can develop efficient cooling devices. The existing passive flow based cooling devices still needs improvement to meet the future demands. To improve the efficiency and capacity of these devices, we need to explore and quantify the passive flow happening at nanoscales. Experimental techniques have not advanced enough to study these fundamental phenomena at the nanoscale, an alternative method is to perform theoretical study at nanoscales. Molecular dynamics (MD) simulation is a widely accepted powerful tool for studying a range of fundamental and engineering problems. MD simulations can be utilized to study the passive flow mechanism and heat transfer due to it. To study passive flow using MD, apart from the conventional methods available in MD, we need to have methods to simulate the heat transfer between solid and liquid, local pressure, surface tension, density, temperature calculation methods, realistic boundary conditions, etc. Heat transfer between solid and fluids has been a challenging area in MD simulations, and has only been minimally explored (especially for a practical fluid like water). Conventionally, an

Improving Passive Time Reversal Underwater Acoustic Communications Using Subarray Processing.

PubMed

He, Chengbing; Jing, Lianyou; Xi, Rui; Li, Qinyuan; Zhang, Qunfei

2017-04-24

Multichannel receivers are usually employed in high-rate underwater acoustic communication to achieve spatial diversity. In the context of multichannel underwater acoustic communications, passive time reversal (TR) combined with a single-channel adaptive decision feedback equalizer (TR-DFE) is a low-complexity solution to achieve both spatial and temporal focusing. In this paper, we present a novel receiver structure to combine passive time reversal with a low-order multichannel adaptive decision feedback equalizer (TR-MC-DFE) to improve the performance of the conventional TR-DFE. First, the proposed method divides the whole received array into several subarrays. Second, we conduct passive time reversal processing in each subarray. Third, the multiple subarray outputs are equalized with a low-order multichannel DFE. We also investigated different channel estimation methods, including least squares (LS), orthogonal matching pursuit (OMP), and improved proportionate normalized least mean squares (IPNLMS). The bit error rate (BER) and output signal-to-noise ratio (SNR) performances of the receiver algorithms are evaluated using simulation and real data collected in a lake experiment. The source-receiver range is 7.4 km, and the data rate with quadrature phase shift keying (QPSK) signal is 8 kbits/s. The uncoded BER of the single input multiple output (SIMO) systems varies between 1 × 10 - 1 and 2 × 10 - 2 for the conventional TR-DFE, and between 1 × 10 - 2 and 1 × 10 - 3 for the proposed TR-MC-DFE when eight hydrophones are utilized. Compared to conventional TR-DFE, the average output SNR of the experimental data is enhanced by 3 dB.

Surface passivation process of compound semiconductor material using UV photosulfidation

DOEpatents

Ashby, Carol I. H.

1995-01-01

A method for passivating compound semiconductor surfaces by photolytically disrupting molecular sulfur vapor with ultraviolet radiation to form reactive sulfur which then reacts with and passivates the surface of compound semiconductors.

Passive perception system for day/night autonomous off-road navigation

NASA Astrophysics Data System (ADS)

Rankin, Arturo L.; Bergh, Charles F.; Goldberg, Steven B.; Bellutta, Paolo; Huertas, Andres; Matthies, Larry H.

2005-05-01

Passive perception of terrain features is a vital requirement for military related unmanned autonomous vehicle operations, especially under electromagnetic signature management conditions. As a member of Team Raptor, the Jet Propulsion Laboratory developed a self-contained passive perception system under the DARPA funded PerceptOR program. An environmentally protected forward-looking sensor head was designed and fabricated in-house to straddle an off-the-shelf pan-tilt unit. The sensor head contained three color cameras for multi-baseline daytime stereo ranging, a pair of cooled mid-wave infrared cameras for nighttime stereo ranging, and supporting electronics to synchronize captured imagery. Narrow-baseline stereo provided improved range data density in cluttered terrain, while wide-baseline stereo provided more accurate ranging for operation at higher speeds in relatively open areas. The passive perception system processed stereo images and outputted over a local area network terrain maps containing elevation, terrain type, and detected hazards. A novel software architecture was designed and implemented to distribute the data processing on a 533MHz quad 7410 PowerPC single board computer under the VxWorks real-time operating system. This architecture, which is general enough to operate on N processors, has been subsequently tested on Pentium-based processors under Windows and Linux, and a Sparc based-processor under Unix. The passive perception system was operated during FY04 PerceptOR program evaluations at Fort A. P. Hill, Virginia, and Yuma Proving Ground, Arizona. This paper discusses the Team Raptor passive perception system hardware and software design, implementation, and performance, and describes a road map to faster and improved passive perception.

Snap Your Fingers! An ERP/sLORETA Study Investigating Implicit Processing of Self- vs. Other-Related Movement Sounds Using the Passive Oddball Paradigm

PubMed Central

Justen, Christoph; Herbert, Cornelia

2016-01-01

So far, neurophysiological studies have investigated implicit and explicit self-related processing particularly for self-related stimuli such as the own face or name. The present study extends previous research to the implicit processing of self-related movement sounds and explores their spatio-temporal dynamics. Event-related potentials (ERPs) were assessed while participants (N = 12 healthy subjects) listened passively to previously recorded self- and other-related finger snapping sounds, presented either as deviants or standards during an oddball paradigm. Passive listening to low (500 Hz) and high (1000 Hz) pure tones served as additional control. For self- vs. other-related finger snapping sounds, analysis of ERPs revealed significant differences in the time windows of the N2a/MMN and P3. An subsequent source localization analysis with standardized low-resolution brain electromagnetic tomography (sLORETA) revealed increased cortical activation in distinct motor areas such as the supplementary motor area (SMA) in the N2a/mismatch negativity (MMN) as well as the P3 time window during processing of self- and other-related finger snapping sounds. In contrast, brain regions associated with self-related processing [e.g., right anterior/posterior cingulate cortex (ACC/PPC)] as well as the right inferior parietal lobule (IPL) showed increased activation particularly during processing of self- vs. other-related finger snapping sounds in the time windows of the N2a/MMN (ACC/PCC) or the P3 (IPL). None of these brain regions showed enhanced activation while listening passively to low (500 Hz) and high (1000 Hz) pure tones. Taken together, the current results indicate (1) a specific role of motor regions such as SMA during auditory processing of movement-related information, regardless of whether this information is self- or other-related, (2) activation of neural sources such as the ACC/PCC and the IPL during implicit processing of self-related movement stimuli, and (3

Systematic Satellite Observations of the Impact of Aerosols from Passive Volcanic Degassing on Local Cloud Properties

NASA Technical Reports Server (NTRS)

Ebmeier, S.K.; Sayer, Andrew M.; Grainger, R. G.; Mather, T. A.; Carboni, E.

2014-01-01

The impact of volcanic emissions, especially from passive degassing and minor explosions, is a source of uncertainty in estimations of aerosol indirect effects. Observations of the impact of volcanic aerosol on clouds contribute to our understanding of both present-day atmospheric properties and of the pre-industrial baseline necessary to assess aerosol radiative forcing. We present systematic measurements over several years at multiple active and inactive volcanic islands in regions of low present-day aerosol burden. The timeaveraged indirect aerosol effects within 200 kilometers downwind of island volcanoes are observed using Moderate Resolution Imaging Spectroradiometer (MODIS, 2002-2013) and Advanced Along-Track Scanning Radiometer (AATSR, 2002- 2008) data. Retrievals of aerosol and cloud properties at Kilauea (Hawaii), Yasur (Vanuatu) and Piton de la Fournaise (la Reunion) are rotated about the volcanic vent to be parallel to wind direction, so that upwind and downwind retrievals can be compared. The emissions from all three volcanoes - including those from passive degassing, Strombolian activity and minor explosions - lead to measurably increased aerosol optical depth downwind of the active vent. Average cloud droplet effective radius is lower downwind of the volcano in all cases, with the peak difference ranging from 2 - 8 micrometers at the different volcanoes in different seasons. Estimations of the difference in Top of Atmosphere upward Short Wave flux upwind and downwind of the active volcanoes from NASA's Clouds and the Earth's Radiant Energy System (CERES) suggest a downwind elevation of between 10 and 45 Watts per square meter at distances of 150 - 400 kilometers from the volcano, with much greater local (less than 80 kilometers) effects. Comparison of these observations with cloud properties at isolated islands without degassing or erupting volcanoes suggests that these patterns are not purely orographic in origin. Our observations of unpolluted

Signal processing in local neuronal circuits based on activity-dependent noise and competition

NASA Astrophysics Data System (ADS)

Volman, Vladislav; Levine, Herbert

2009-09-01

We study the characteristics of weak signal detection by a recurrent neuronal network with plastic synaptic coupling. It is shown that in the presence of an asynchronous component in synaptic transmission, the network acquires selectivity with respect to the frequency of weak periodic stimuli. For nonperiodic frequency-modulated stimuli, the response is quantified by the mutual information between input (signal) and output (network's activity) and is optimized by synaptic depression. Introducing correlations in signal structure resulted in the decrease in input-output mutual information. Our results suggest that in neural systems with plastic connectivity, information is not merely carried passively by the signal; rather, the information content of the signal itself might determine the mode of its processing by a local neuronal circuit.

Improving Passive Time Reversal Underwater Acoustic Communications Using Subarray Processing

PubMed Central

He, Chengbing; Jing, Lianyou; Xi, Rui; Li, Qinyuan; Zhang, Qunfei

2017-01-01

Multichannel receivers are usually employed in high-rate underwater acoustic communication to achieve spatial diversity. In the context of multichannel underwater acoustic communications, passive time reversal (TR) combined with a single-channel adaptive decision feedback equalizer (TR-DFE) is a low-complexity solution to achieve both spatial and temporal focusing. In this paper, we present a novel receiver structure to combine passive time reversal with a low-order multichannel adaptive decision feedback equalizer (TR-MC-DFE) to improve the performance of the conventional TR-DFE. First, the proposed method divides the whole received array into several subarrays. Second, we conduct passive time reversal processing in each subarray. Third, the multiple subarray outputs are equalized with a low-order multichannel DFE. We also investigated different channel estimation methods, including least squares (LS), orthogonal matching pursuit (OMP), and improved proportionate normalized least mean squares (IPNLMS). The bit error rate (BER) and output signal-to-noise ratio (SNR) performances of the receiver algorithms are evaluated using simulation and real data collected in a lake experiment. The source-receiver range is 7.4 km, and the data rate with quadrature phase shift keying (QPSK) signal is 8 kbits/s. The uncoded BER of the single input multiple output (SIMO) systems varies between 1×10−1 and 2×10−2 for the conventional TR-DFE, and between 1×10−2 and 1×10−3 for the proposed TR-MC-DFE when eight hydrophones are utilized. Compared to conventional TR-DFE, the average output SNR of the experimental data is enhanced by 3 dB. PMID:28441763

Processing implicit control: evidence from reading times

PubMed Central

McCourt, Michael; Green, Jeffrey J.; Lau, Ellen; Williams, Alexander

2015-01-01

Sentences such as “The ship was sunk to collect the insurance” exhibit an unusual form of anaphora, implicit control, where neither anaphor nor antecedent is audible. The non-finite reason clause has an understood subject, PRO, that is anaphoric; here it may be understood as naming the agent of the event of the host clause. Yet since the host is a short passive, this agent is realized by no audible dependent. The putative antecedent to PRO is therefore implicit, which it normally cannot be. What sorts of representations subserve the comprehension of this dependency? Here we present four self-paced reading time studies directed at this question. Previous work showed no processing cost for implicit vs. explicit control, and took this to support the view that PRO is linked syntactically to a silent argument in the passive. We challenge this conclusion by reporting that we also find no processing cost for remote implicit control, as in: “The ship was sunk. The reason was to collect the insurance.” Here the dependency crosses two independent sentences, and so cannot, we argue, be mediated by syntax. Our Experiments 1–4 examined the processing of both implicit (short passive) and explicit (active or long passive) control in both local and remote configurations. Experiments 3 and 4 added either “3 days ago” or “just in order” to the local conditions, to control for the distance between the passive and infinitival verbs, and for the predictability of the reason clause, respectively. We replicate the finding that implicit control does not impose an additional processing cost. But critically we show that remote control does not impose a processing cost either. Reading times at the reason clause were never slower when control was remote. In fact they were always faster. Thus, efficient processing of local implicit control cannot show that implicit control is mediated by syntax; nor, in turn, that there is a silent but grammatically active argument in

Passivation process and the mechanism of packing particles in the Fe0/GAC system during the treatment of ABS resin wastewater.

PubMed

Lai, Bo; Zhou, Yuexi; Wang, Juling; Zhang, Yunhong; Chen, Zhiqiang

2014-01-01

This study provides mechanistic insights into the passivation of the packing particles during the treatment of acrylonitrile-butadiene-styrene (ABS) resin wastewater by the Fe0/GAC system. The granular-activated carbon (GAC) and iron chippings (Fe0) were mixed together with a volumetric ratio of 1:1. GAC has a mean particle size of approximately 3-5 mm, a specific surface of 748 m2 g(-1), a total pore volume of 0.48 mL g(-1) and a bulk density of 0.49 g cm(-3). The iron chippings have a compact and non-porous surface morphology. The results show that the packing particles in the Fe0/GAC system would lose their activity because the removal of TOC and PO4(3-) for ABS resin wastewater could not carried out by the Fe0/GAC system after 40 days continuous running. Meanwhile, the availability of O2 and intrinsic reactivity of Fe0 play a key role on the form of passive film with different iron oxidation states. The passive film on the surface of iron chippings was formed by two phases: (a) local corrosion phase (0-20 d) and (b) co-precipitation phase (20-40 d), while that of GAC was mainly formed by the co-precipitation of corrosion products with SO4(2-) and PO4(3-) because SO4(2-) and PO4(3-) would not easily reach the Fe0 surface. Therefore, in order to avoid the occurrence of filler passivation, high concentrations of SO4(2-) and PO4(3-) in wastewater should be removed before the treatment process of the Fe/GAC system.

Role of Passive Diffusion, Transporters, and Membrane Trafficking-Mediated Processes in Cellular Drug Transport.

PubMed

Cocucci, E; Kim, J Y; Bai, Y; Pabla, N

2017-01-01

Intracellular drug accumulation is thought to be dictated by two major processes, passive diffusion through the lipid membrane or membrane transporters. The relative role played by these distinct processes remains actively debated. Moreover, the role of membrane-trafficking in drug transport remains underappreciated and unexplored. Here we discuss the distinct processes involved in cellular drug distribution and propose that better experimental models are required to elucidate the differential contributions of various processes in intracellular drug accumulation. © 2016 American Society for Clinical Pharmacology and Therapeutics.

Local structure of scalar flux in turbulent passive scalar mixing

NASA Astrophysics Data System (ADS)

Konduri, Aditya; Donzis, Diego

2012-11-01

Understanding the properties of scalar flux is important in the study of turbulent mixing. Classical theories suggest that it mainly depends on the large scale structures in the flow. Recent studies suggest that the mean scalar flux reaches an asymptotic value at high Peclet numbers, independent of molecular transport properties of the fluid. A large DNS database of isotropic turbulence with passive scalars forced with a mean scalar gradient with resolution up to 40963, is used to explore the structure of scalar flux based on the local topology of the flow. It is found that regions of small velocity gradients, where dissipation and enstrophy are small, constitute the main contribution to scalar flux. On the other hand, regions of very small scalar gradient (and scalar dissipation) become less important to the scalar flux at high Reynolds numbers. The scaling of the scalar flux spectra is also investigated. The k - 7 / 3 scaling proposed by Lumley (1964) is observed at high Reynolds numbers, but collapse is not complete. A spectral bump similar to that in the velocity spectrum is observed close to dissipative scales. A number of features, including the height of the bump, appear to reach an asymptotic value at high Schmidt number.

High-throughput countercurrent microextraction in passive mode.

PubMed

Xie, Tingliang; Xu, Cong

2018-05-15

Although microextraction is much more efficient than conventional macroextraction, its practical application has been limited by low throughputs and difficulties in constructing robust countercurrent microextraction (CCME) systems. In this work, a robust CCME process was established based on a novel passive microextractor with four units without any moving parts. The passive microextractor has internal recirculation and can efficiently mix two immiscible liquids. The hydraulic characteristics as well as the extraction and back-extraction performance of the passive CCME were investigated experimentally. The recovery efficiencies of the passive CCME were 1.43-1.68 times larger than the best values achieved using cocurrent extraction. Furthermore, the total throughput of the passive CCME developed in this work was about one to three orders of magnitude higher than that of other passive CCME systems reported in the literature. Therefore, a robust CCME process with high throughputs has been successfully constructed, which may promote the application of passive CCME in a wide variety of fields.

Adaptive behaviors in multi-agent source localization using passive sensing.

PubMed

Shaukat, Mansoor; Chitre, Mandar

2016-12-01

In this paper, the role of adaptive group cohesion in a cooperative multi-agent source localization problem is investigated. A distributed source localization algorithm is presented for a homogeneous team of simple agents. An agent uses a single sensor to sense the gradient and two sensors to sense its neighbors. The algorithm is a set of individualistic and social behaviors where the individualistic behavior is as simple as an agent keeping its previous heading and is not self-sufficient in localizing the source. Source localization is achieved as an emergent property through agent's adaptive interactions with the neighbors and the environment. Given a single agent is incapable of localizing the source, maintaining team connectivity at all times is crucial. Two simple temporal sampling behaviors, intensity-based-adaptation and connectivity-based-adaptation, ensure an efficient localization strategy with minimal agent breakaways. The agent behaviors are simultaneously optimized using a two phase evolutionary optimization process. The optimized behaviors are estimated with analytical models and the resulting collective behavior is validated against the agent's sensor and actuator noise, strong multi-path interference due to environment variability, initialization distance sensitivity and loss of source signal.

Citric Acid Passivation of Stainless Steel

NASA Technical Reports Server (NTRS)

Yasensky, David; Reali, John; Larson, Chris; Carl, Chad

2009-01-01

Passivation is a process for cleaning and providing corrosion protection for stainless steel. Currently, on Kennedy Space Center (KSC), only parts passivated with nitric acid are acceptable for use. KSC disposes of approximately 125gal of concentrated nitric acid per year, and receives many parts from vendors who must also dispose of used nitric acid. Unfortunately, nitric acid presents health and environmental hazards. As a result, several recent industry studies have examined citric acid as an alternative. Implementing a citric acid-based passivation procedure would improve the health and environmental safety aspects of passivation process. However although there is a lack of published studies that conclusively prove citric acid is a technically sound passivation agent. In 2007, NASA's KSC Materials Advisory Working Group requested the evaluation of citric acid in place of nitric acid for passivation of parts at KSC. United Space Alliance Materials & Processes engineers have developed a three-phase test plan to evaluate citric acid as an alternative to nitric acid on three stainless steels commonly used at KSC: UNS S30400, S41000, and S17400. Phases 1 and 2 will produce an optimized citric acid treatment based on results from atmospheric exposure at NASA's Beach Corrosion Facility. Phase 3 will compare the optimized solution(s) with nitric acid treatments. If the results indicate that citric acid passivates as well or better than nitric acid, NASA intends to approve this method for parts used at the Kennedy Space Center.

High sensitivity broadband 360GHz passive receiver for TeraSCREEN

NASA Astrophysics Data System (ADS)

Wang, Hui; Oldfield, Matthew; Maestrojuán, Itziar; Platt, Duncan; Brewster, Nick; Viegas, Colin; Alderman, Byron; Ellison, Brian N.

2016-05-01

TeraSCREEN is an EU FP7 Security project aimed at developing a combined active, with frequency channel centered at 360 GHz, and passive, with frequency channels centered at 94, 220 and 360 GHz, imaging system for border controls in airport and commercial ferry ports. The system will include automatic threat detection and classification and has been designed with a strong focus on the ethical, legal and practical aspects of operating in these environments and with the potential threats in mind. Furthermore, both the passive and active systems are based on array receivers with the active system consisting of a 16 element MIMO FMCW radar centered at 360 GHz with a bandwidth of 30 GHz utilizing a custom made direct digital synthesizer. The 16 element passive receiver system at 360 GHz uses commercial Gunn diode oscillators at 90 GHz followed by custom made 90 to 180 GHz frequency doublers supplying the local oscillator for 360 GHz sub-harmonic mixers. This paper describes the development of the passive antenna module, local oscillator chain, frequency mixers and detectors used in the passive receiver array of this system. The complete passive receiver chain is characterized in this paper.

Evidence for equivalence of diffusion processes of passive scalar and magnetic fields in anisotropic Navier-Stokes turbulence.

PubMed

Jurčišinová, E; Jurčišin, M

2017-05-01

The influence of the uniaxial small-scale anisotropy on the kinematic magnetohydrodynamic turbulence is investigated by using the field theoretic renormalization group technique in the one-loop approximation of a perturbation theory. The infrared stable fixed point of the renormalization group equations, which drives the scaling properties of the model in the inertial range, is investigated as the function of the anisotropy parameters and it is shown that, at least at the one-loop level of approximation, the diffusion processes of the weak passive magnetic field in the anisotropically driven kinematic magnetohydrodynamic turbulence are completely equivalent to the corresponding diffusion processes of passively advected scalar fields in the anisotropic Navier-Stokes turbulent environments.

Atomic Scale Understanding of Poly-Si/SiO2/c-Si Passivated Contacts: Passivation Degradation Due to Metallization

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

Aguiar, Jeffery A.; Young, David; Lee, Benjamin

2016-11-21

The key attributes for achieving high efficiency crystalline silicon solar cells include class leading developments in the ability to approach the theoretical limits of silicon solar technology (29.4% efficiency). The push for high efficiency devices is further compounded with the clear need for passivation to reduce recombination at the metal contacts. At the same time there is stringent requirement to retain the same material device quality, surface passivation, and performance characteristics following subsequent processing. The development of passivated silicon cell structures that retain active front and rear surface passivation and overall material cell quality is therefore a relevant and activemore » area of development. To address the potential outcomes of metallization on passivated silicon stack, we report on some common microstructural features of degradation due to metallization for a series of silicon device stacks. A fundamental materials understanding of the metallization process on retaining high-efficiency passivated Si devices is therefore gained over these series of results.« less

Investigating the 3-D Subduction Initiation Processes at Transform Faults and Passive Margins

NASA Astrophysics Data System (ADS)

Peng, H.; Leng, W.

2017-12-01

Studying the processes of subduction initiation is a key for understanding the Wilson cycle and improving the theory of plate tectonics. Previous studies investigated subduction initiation with geological synthesis and geodynamic modeling methods, discovering that subduction intends to initiate at the transform faults close to oceanic arcs, and that its evolutionary processes and surface volcanic expressions are controlled by plate strength. However, these studies are mainly conducted with 2-D models, which cannot deal with lateral heterogeneities of crustal thickness and strength along the plate interfaces. Here we extend the 2-D model to a 3-D parallel subduction model with high computational efficiency. With the new model, we study the dynamic controlling factors, morphology evolutionary processes and surface expressions for subduction initiation with lateral heterogeneities of material properties along transform faults and passive margins. We find that lateral lithospheric heterogeneities control the starting point of the subduction initiation along the newly formed trenches and the propagation speed for the trench formation. New subduction tends to firstly initiate at the property changing point along the transform faults or passive margins. Such finds may be applied to explain the formation process of the Izu-Bonin-Mariana (IBM) subduction zone in the western Pacific and the Scotia subduction zone at the south end of the South America. Our results enhance our understanding for the formation of new trenches and help to provide geodynamic modeling explanations for the observed remnant slabs in the upper mantle and the surface volcanic expressions.

Electrochemical and Passive Behaviors of Pure Copper Fabricated by Accumulative Roll-Bonding (ARB) Process

NASA Astrophysics Data System (ADS)

Imantalab, O.; Fattah-alhosseini, A.

2015-07-01

In the present work, electrochemical and passive behaviors of pure copper fabricated by accumulative roll-bonding (ARB) process in 0.01 M borax solution (pH = 9.1) have been studied. Before any electrochemical measurements, evaluation of microstructure was obtained by Vickers microhardness, x-ray diffraction (XRD), and transmission electron microscopy. The results of microhardness tests revealed that microhardness values increased with the increasing number of ARB cycles. Also a sharp increase was seen in microhardness after the first ARB cycle, whereas mediocre additional increases were observed afterward up to the seven cycles. Moreover, XRD patterns showed that the mean crystallite size values decrease with the increasing number of ARB cycles. To investigate the electrochemical and passive behaviors of the samples, the potentiodynamic polarization, Mott-Schottky analysis and electrochemical impedance spectroscopy (EIS) were carried out. Polarization plots revealed that as a result of ARB, the corrosion behavior of the specimens improves compared with the annealed pure copper. Also, the Mott-Schottky analysis and EIS measurements showed that the increasing number of ARB cycles offer better conditions for forming the passive films with higher protection behavior, due to the growth of less-defective films.

Measure Guideline: Passive Vents

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

Berger, David; Neri, Robin

2016-02-05

This document addresses the use of passive vents as a source of outdoor air in multifamily buildings. The challenges associated with implementing passive vents and the factors affecting performance are outlined. A comprehensive design methodology and quantified performance metrics are provided. Two hypothetical design examples are provided to illustrate the process. This document is intended to be useful to designers, decision-makers, and contractors implementing passive ventilation strategies. It is also intended to be a resource for those responsible for setting high-performance building program requirements, especially pertaining to ventilation and outdoor air. To ensure good indoor air quality, a dedicated sourcemore » of outdoor air is an integral part of high-performance buildings. Presently, there is a lack of guidance pertaining to the design and installation of passive vents, resulting in poor system performance. This report details the criteria necessary for designing, constructing, and testing passive vent systems to enable them to provide consistent and reliable levels of ventilation air from outdoors.« less

Deploying Monitoring Trails for Fault Localization in All- Optical Networks and Radio-over-Fiber Passive Optical Networks

NASA Astrophysics Data System (ADS)

Maamoun, Khaled Mohamed

Fault localization is the process of realizing the true source of a failure from a set of collected failure notifications. Isolating failure recovery within the network optical domain is necessary to resolve alarm storm problems. The introduction of the monitoring trail (m-trail) has been proven to deliver better performance by employing monitoring resources in a form of optical trails - a monitoring framework that generalizes all the previously reported counterparts. In this dissertation, the m-trail design is explored and a focus is given to the analysis on using m-trails with established lightpaths to achieve fault localization. This process saves network resources by reducing the number of the m-trails required for fault localization and therefore the number of wavelengths used in the network. A novel approach based on Geographic Midpoint Technique, an adapted version of the Chinese Postman's Problem (CPP) solution and an adapted version of the Traveling Salesman's Problem (TSP) solution algorithms is introduced. The desirable features of network architectures and the enabling of innovative technologies for delivering future millimeter-waveband (mm-WB) Radio-over-Fiber (RoF) systems for wireless services integrated in a Dense Wavelength Division Multiplexing (DWDM) is proposed in this dissertation. For the conceptual illustration, a DWDM RoF system with channel spacing of 12.5 GHz is considered. The mm-WB Radio Frequency (RF) signal is obtained at each Optical Network Unit (ONU) by simultaneously using optical heterodyning photo detection between two optical carriers. The generated RF modulated signal has a frequency of 12.5 GHz. This RoF system is easy, cost-effective, resistant to laser phase noise and also reduces maintenance needs, in principle. A revision of related RoF network proposals and experiments is also included. A number of models for Passive Optical Networks (PON)/ RoF-PON that combine both innovative and existing ideas along with a number of

Tracking marine mammals using passive acoustics

NASA Astrophysics Data System (ADS)

Nosal, Eva-Marie

2007-12-01

It is difficult to study the behavior and physiology of marine mammals or to understand and mitigate human impact on them because much of their lives are spent underwater. Since sound propagates for long distances in the ocean and since many cetaceans are vocal, passive acoustics is a valuable tool for studying and monitoring their behavior. After a brief introduction to and review of passive acoustic tracking methods, this dissertation develops and applies two new methods. Both methods use widely-spaced (tens of kilometers) bottom-mounted hydrophone arrays, as well as propagation models that account for depth-dependent sound speed profiles. The first passive acoustic tracking method relies on arrival times of direct and surface-reflected paths. It is used to track a sperm whale using 5 at the Atlantic Undersea Test and Evaluation Center (AUTEC) and gives position estimates that are accurate to within 10 meters. With such accuracy, the whale's pitch and yaw are estimated by assuming that its main axis (which points from the tail to the rostrum) is parallel to its velocity. Roll is found by fitting the details of the pulses within each sperm whale click to the so-called bent horn model of sperm whale sound production. Finally, given the position and orientation of the whale, its beam pattern is reconstructed and found to be highly directional with an intense forward directed component. Pair-wise spectrogram (PWS) processing is the second passive acoustic tracking method developed in this dissertation. Although it is computationally more intensive, PWS has several advantages over arrival-time tracking methods, especially in shallow water environments, for long duration calls, and for multiple-animal datasets, as is the case for humpback whales on Hawaiian breeding grounds. Results of simulations with realistic noise conditions and environmental mismatch are given and compared to other passive localization techniques. When applied to the AUTEC sperm whale dataset, PWS

Array processing for RFID tag localization exploiting multi-frequency signals

NASA Astrophysics Data System (ADS)

Zhang, Yimin; Li, Xin; Amin, Moeness G.

2009-05-01

RFID is an increasingly valuable business and technology tool for electronically identifying, locating, and tracking products, assets, and personnel. As a result, precise positioning and tracking of RFID tags and readers have received considerable attention from both academic and industrial communities. Finding the position of RFID tags is considered an important task in various real-time locating systems (RTLS). As such, numerous RFID localization products have been developed for various applications. The majority of RFID positioning systems is based on the fusion of pieces of relevant information, such as the range and the direction-of-arrival (DOA). For example, trilateration can determine the tag position by using the range information of the tag estimated from three or more spatially separated reader antennas. Triangulation is another method to locate RFID tags that use the direction-of-arrival (DOA) information estimated at multiple spatially separated locations. The RFID tag positions can also be determined through hybrid techniques that combine the range and DOA information. The focus of this paper to study the design and performance of the localization of passive RFID tags using array processing techniques in a multipath environment, and exploiting multi-frequency CW signals. The latter are used to decorrelate the coherent multipath signals for effective DOA estimation and for the purpose of accurate range estimation. Accordingly, the spatial and frequency dimensionalities are fully utilized for robust and accurate positioning of RFID tags.

Local oscillator induced degradation of medium-term stability in passive atomic frequency standards

NASA Technical Reports Server (NTRS)

Dick, G. John; Prestage, John D.; Greenhall, Charles A.; Maleki, Lute

1990-01-01

As the performance of passive atomic frequency standards improves, a new limitation is encountered due to frequency fluctuations in an ancillary local oscillator (L.O.). The effect is due to time variation in the gain of the feedback which compensates L.O. frequency fluctuations. The high performance promised by new microwave and optical trapped ion standards may be severely compromised by this effect. Researchers present an analysis of this performance limitation for the case of sequentially interrogated standards. The time dependence of the sensitivity of the interrogation process to L.O. frequency fluctuations is evaluated for single-pulse and double-pulse Ramsey RF interrogation and for amplitude modulated pulses. The effect of these various time dependencies on performance of the standard is calculated for an L.O. with frequency fluctuations showing a typical 1/f spectral density. A limiting 1/sq. root gamma dependent deviation of frequency fluctuations is calculated as a function of pulse lengths, dead time, and pulse overlap. Researchers also present conceptual and hardware-oriented solutions to this problem which achieve a much more nearly constant sensitivity to L.O. fluctuations. Solutions involve use of double-pulse interrogation; alternate interrogation of multiple traps so that the dead time of one trap can be covered by operation of the other; and the use of double-pulse interrogation for two traps, so that during the time of the RF pulses, the increasing sensitivity of one trap tends to compensate for the decreasing sensitivity of the other. A solution making use of amplified-modulated pulses is also presented which shows nominally zero time variation.

Skin blood flow and local temperature independently modify sweat rate during passive heat stress in humans.

PubMed

Wingo, Jonathan E; Low, David A; Keller, David M; Brothers, R Matthew; Shibasaki, Manabu; Crandall, Craig G

2010-11-01

Sweat rate (SR) is reduced in locally cooled skin, which may result from decreased temperature and/or parallel reductions in skin blood flow. The purpose of this study was to test the hypotheses that decreased skin blood flow and decreased local temperature each independently attenuate sweating. In protocols I and II, eight subjects rested supine while wearing a water-perfused suit for the control of whole body skin and internal temperatures. While 34°C water perfused the suit, four microdialysis membranes were placed in posterior forearm skin not covered by the suit to manipulate skin blood flow using vasoactive agents. Each site was instrumented for control of local temperature and measurement of local SR (capacitance hygrometry) and skin blood flow (laser-Doppler flowmetry). In protocol I, two sites received norepinephrine to reduce skin blood flow, while two sites received Ringer solution (control). All sites were maintained at 34°C. In protocol II, all sites received 28 mM sodium nitroprusside to equalize skin blood flow between sites before local cooling to 20°C (2 sites) or maintenance at 34°C (2 sites). In both protocols, individuals were then passively heated to increase core temperature ~1°C. Both decreased skin blood flow and decreased local temperature attenuated the slope of the SR to mean body temperature relationship (2.0 ± 1.2 vs. 1.0 ± 0.7 mg·cm(-2)·min(-1)·°C(-1) for the effect of decreased skin blood flow, P = 0.01; 1.2 ± 0.9 vs. 0.07 ± 0.05 mg·cm(-2)·min(-1)·°C(-1) for the effect of decreased local temperature, P = 0.02). Furthermore, local cooling delayed the onset of sweating (mean body temperature of 37.5 ± 0.4 vs. 37.6 ± 0.4°C, P = 0.03). These data demonstrate that local cooling attenuates sweating by independent effects of decreased skin blood flow and decreased local skin temperature.

Most energetic passive states.

PubMed

Perarnau-Llobet, Martí; Hovhannisyan, Karen V; Huber, Marcus; Skrzypczyk, Paul; Tura, Jordi; Acín, Antonio

2015-10-01

Passive states are defined as those states that do not allow for work extraction in a cyclic (unitary) process. Within the set of passive states, thermal states are the most stable ones: they maximize the entropy for a given energy, and similarly they minimize the energy for a given entropy. Here we find the passive states lying in the other extreme, i.e., those that maximize the energy for a given entropy, which we show also minimize the entropy when the energy is fixed. These extremal properties make these states useful to obtain fundamental bounds for the thermodynamics of finite-dimensional quantum systems, which we show in several scenarios.

Passivated niobium cavities

DOEpatents

Myneni, Ganapati Rao [Yorktown, VA; Hjorvarsson, Bjorgvin [Lagga Arby, SE; Ciovati, Gianluigi [Newport News, VA

2006-12-19

A niobium cavity exhibiting high quality factors at high gradients is provided by treating a niobium cavity through a process comprising: 1) removing surface oxides by plasma etching or a similar process; 2) removing hydrogen or other gases absorbed in the bulk niobium by high temperature treatment of the cavity under ultra high vacuum to achieve hydrogen outgassing; and 3) assuring the long term chemical stability of the niobium cavity by applying a passivating layer of a superconducting material having a superconducting transition temperature higher than niobium thereby reducing losses from electron (cooper pair) scattering in the near surface region of the interior of the niobium cavity. According to a preferred embodiment, the passivating layer comprises niobium nitride (NbN) applied by reactive sputtering.

Passive stimulation and behavioral training differentially transform temporal processing in the inferior colliculus and primary auditory cortex

PubMed Central

Beitel, Ralph E.; Schreiner, Christoph E.; Leake, Patricia A.

2016-01-01

In profoundly deaf cats, behavioral training with intracochlear electric stimulation (ICES) can improve temporal processing in the primary auditory cortex (AI). To investigate whether similar effects are manifest in the auditory midbrain, ICES was initiated in neonatally deafened cats either during development after short durations of deafness (8 wk of age) or in adulthood after long durations of deafness (≥3.5 yr). All of these animals received behaviorally meaningless, “passive” ICES. Some animals also received behavioral training with ICES. Two long-deaf cats received no ICES prior to acute electrophysiological recording. After several months of passive ICES and behavioral training, animals were anesthetized, and neuronal responses to pulse trains of increasing rates were recorded in the central (ICC) and external (ICX) nuclei of the inferior colliculus. Neuronal temporal response patterns (repetition rate coding, minimum latencies, response precision) were compared with results from recordings made in the AI of the same animals (Beitel RE, Vollmer M, Raggio MW, Schreiner CE. J Neurophysiol 106: 944–959, 2011; Vollmer M, Beitel RE. J Neurophysiol 106: 2423–2436, 2011). Passive ICES in long-deaf cats remediated severely degraded temporal processing in the ICC and had no effects in the ICX. In contrast to observations in the AI, behaviorally relevant ICES had no effects on temporal processing in the ICC or ICX, with the single exception of shorter latencies in the ICC in short-deaf cats. The results suggest that independent of deafness duration passive stimulation and behavioral training differentially transform temporal processing in auditory midbrain and cortex, and primary auditory cortex emerges as a pivotal site for behaviorally driven neuronal temporal plasticity in the deaf cat. NEW & NOTEWORTHY Behaviorally relevant vs. passive electric stimulation of the auditory nerve differentially affects neuronal temporal processing in the central nucleus of

The structure of turbulent channel flow with passive scalar transport

NASA Technical Reports Server (NTRS)

Guezennec, Y.; Stretch, D.; Kim, J.

1990-01-01

The simulation of turbulent channel flow, with various passive markers, was examined to investigate the local mechanisms of passive scalar transport. We found significant differences between the local transport of heat and momentum, even when the molecular and turbulent Prandtl numbers are of order one. These discrepancies can be attributed to the role of the pressure. We also found that the heat is a poor marker of the vorticity field outside of the near wall region and that scalar transport over significant distances results from the aggregate effect of many turbulent eddies.

The multi-faceted role of allergen exposure to the local airway mucosa.

PubMed

Golebski, K; Röschmann, K I L; Toppila-Salmi, S; Hammad, H; Lambrecht, B N; Renkonen, R; Fokkens, W J; van Drunen, C M

2013-02-01

Airway epithelial cells are the first to encounter aeroallergens and therefore have recently become an interesting target of many studies investigating their involvement in the modulation of allergic inflammatory responses. Disruption of a passive structural barrier composed of epithelial cells by intrinsic proteolytic activity of allergens may facilitate allergen penetration into local tissues and additionally affect chronic and ongoing inflammatory processes in respiratory tissues. Furthermore, the ability of rhinoviruses to disrupt and interfere with epithelial tight junctions may alter the barrier integrity and enable a passive passage of inhaled allergens through the airway epithelium. On the other hand, epithelial cells are no longer considered to act only as a physical barrier toward inhaled allergens, but also to actively contribute to airway inflammation by detecting and responding to environmental factors. Epithelial cells can produce mediators, which may affect the recruitment and activation of more specialized immune cells to the local tissue and also create a microenvironment in which these activated immune cells may function and propagate the inflammatory processes. This review presents the dual role of epithelium acting as a passive and active barrier when encountering an inhaled allergen and how this double role contributes to the start of local immune responses. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

The Effect of Processing Instruction and Dictogloss Tasks on Acquisition of the English Passive Voice

ERIC Educational Resources Information Center

Qin, Jingjing

2008-01-01

This study was intended to compare processing instruction (VanPatten, 1993, 1996, 2000), an input-based focus on form technique, to dictogloss tasks, an output-oriented focus-on-form type of instruction to assess their effects in helping beginning-EFL (English as a Foreign Language) learners acquire the simple English passive voice. Two intact…

Advanced Demonstration of Motion Correction for Ship-to-Ship Passive Inspections

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

Ziock, Klaus-Peter; Boehnen, Chris Bensing; Ernst, Joseph

2013-09-30

Passive radiation detection is a key tool for detecting illicit nuclear materials. In maritime applications it is most effective against small vessels where attenuation is of less concern. Passive imaging provides: discrimination between localized (threat) and distributed (non-threat) sources, removal of background fluctuations due to nearby shorelines and structures, source localization to an individual craft in crowded waters, and background subtracted spectra. Unfortunately, imaging methods cannot be easily applied in ship-to-ship inspections because relative motion of the vessels blurs the results over many pixels, significantly reducing sensitivity. This is particularly true for the smaller water craft where passive inspections aremore » most valuable. In this project we performed tests and improved the performance of an instrument (developed earlier under, “Motion Correction for Ship-to-Ship Passive Inspections”) that uses automated tracking of a target vessel in visible-light images to generate a 3D radiation map of the target vessel from data obtained using a gamma-ray imager.« less

Deep Reactive Ion Etching (DRIE) of High Aspect Ratio SiC Microstructures using a Time-Multiplexed Etch-Passivate Process

NASA Technical Reports Server (NTRS)

Evans, Laura J.; Beheim, Glenn M.

2006-01-01

High aspect ratio silicon carbide (SiC) microstructures are needed for microengines and other harsh environment micro-electro-mechanical systems (MEMS). Previously, deep reactive ion etching (DRIE) of low aspect ratio (AR less than or = 1) deep (greater than 100 micron) trenches in SiC has been reported. However, existing DRIE processes for SiC are not well-suited for definition of high aspect ratio features because such simple etch-only processes provide insufficient control over sidewall roughness and slope. Therefore, we have investigated the use of a time-multiplexed etch-passivate (TMEP) process, which alternates etching with polymer passivation of the etch sidewalls. An optimized TMEP process was used to etch high aspect ratio (AR greater than 5) deep (less than 100 micron) trenches in 6H-SiC. Power MEMS structures (micro turbine blades) in 6H-SiC were also fabricated.

Improved Stability and Performance of Visible Photoelectrochemical Water Splitting on Solution-Processed Organic Semiconductor Thin Films by Ultrathin Metal Oxide Passivation

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

Wang, Lei; Yan, Danhua; Shaffer, David W.

Solution-processable organic semiconductors have potentials as visible photoelectrochemical (PEC) water splitting photoelectrodes due to their tunable small band gap and electronic energy levels, but they are typically limited by poor stability and photocatalytic activity. In this study, we demonstrate the direct visible PEC water oxidation on solution-processed organic semiconductor thin films with improved stability and performance by ultrathin metal oxide passivation layers. N-type fullerene-derivative thin films passivated by sub-2 nm ZnO via atomic layer deposition enabled the visible PEC water oxidation at wavelengths longer than 600 nm in harsh alkaline electrolyte environments with up to 30 μA/cm 2 photocurrents atmore » the thermodynamic water-oxidation equilibrium potential and the photoanode half-lifetime extended to ~1000 s. The systematic investigation reveals the enhanced water oxidation catalytic activity afforded by ZnO passivation and the charge tunneling governing the hole transfer through passivation layers. Further enhanced PEC performances were realized by improving the bottom ohmic contact to the organic semiconductor, achieving ~60 μA/cm 2 water oxidation photocurrent at the equilibrium potential, the highest values reported for organic semiconductor thin films to our knowledge. The improved stability and performance of passivated organic photoelectrodes and discovered design rationales provide useful guidelines for realizing the stable visible solar PEC water splitting based on organic semiconductor thin films.« less

Improved Stability and Performance of Visible Photoelectrochemical Water Splitting on Solution-Processed Organic Semiconductor Thin Films by Ultrathin Metal Oxide Passivation

DOE PAGES

Wang, Lei; Yan, Danhua; Shaffer, David W.; ...

2017-12-27

Solution-processable organic semiconductors have potentials as visible photoelectrochemical (PEC) water splitting photoelectrodes due to their tunable small band gap and electronic energy levels, but they are typically limited by poor stability and photocatalytic activity. In this study, we demonstrate the direct visible PEC water oxidation on solution-processed organic semiconductor thin films with improved stability and performance by ultrathin metal oxide passivation layers. N-type fullerene-derivative thin films passivated by sub-2 nm ZnO via atomic layer deposition enabled the visible PEC water oxidation at wavelengths longer than 600 nm in harsh alkaline electrolyte environments with up to 30 μA/cm 2 photocurrents atmore » the thermodynamic water-oxidation equilibrium potential and the photoanode half-lifetime extended to ~1000 s. The systematic investigation reveals the enhanced water oxidation catalytic activity afforded by ZnO passivation and the charge tunneling governing the hole transfer through passivation layers. Further enhanced PEC performances were realized by improving the bottom ohmic contact to the organic semiconductor, achieving ~60 μA/cm 2 water oxidation photocurrent at the equilibrium potential, the highest values reported for organic semiconductor thin films to our knowledge. The improved stability and performance of passivated organic photoelectrodes and discovered design rationales provide useful guidelines for realizing the stable visible solar PEC water splitting based on organic semiconductor thin films.« less

Comparison of fMRI data from passive listening and active-response story processing tasks in children

PubMed Central

Vannest, Jennifer J.; Karunanayaka, Prasanna R.; Altaye, Mekibib; Schmithorst, Vincent J.; Plante, Elena M.; Eaton, Kenneth J.; Rasmussen, Jerod M.; Holland, Scott K.

2009-01-01

Purpose To use functional MRI methods to visualize a network of auditory and language-processing brain regions associated with processing an aurally-presented story. We compare a passive listening (PL) story paradigm to an active-response (AR) version including on-line performance monitoring and a sparse acquisition technique. Materials/Methods Twenty children (ages 11−13) completed PL and AR story processing tasks. The PL version presented alternating 30-second blocks of stories and tones; the AR version presented story segments, comprehension questions, and 5s tone sequences, with fMRI acquisitions between stimuli. fMRI data was analyzed using a general linear model approach and paired t-test identifying significant group activation. Results Both tasks activated in primary auditory cortex, superior temporal gyrus bilaterally, left inferior frontal gyrus. The AR task demonstrated more extensive activation, including dorsolateral prefrontal cortex and anterior/posterior cingulate cortex. Comparison of effect size in each paradigm showed a larger effect for the AR paradigm in a left inferior frontal ROI. Conclusion Activation patterns for story processing in children are similar in passive listening and active-response tasks. Increases in extent and magnitude of activation in the AR task are likely associated with memory and attention resources engaged across acquisition intervals. PMID:19306445

Is Broca's Area Involved in the Processing of Passive Sentences? An Event-Related fMRI Study

ERIC Educational Resources Information Center

Yokoyama, Satoru; Watanabe, Jobu; Iwata, Kazuki; Ikuta, Naho; Haji, Tomoki; Usui, Nobuo; Taira, Masato; Miyamoto, Tadao; Nakamura, Wataru; Sato, Shigeru; Horie, Kaoru; Kawashima, Ryuta

2007-01-01

We used functional magnetic resonance imaging (fMRI) to investigate whether activation in Broca's area is greater during the processing of passive versus active sentences in the brains of healthy subjects. Twenty Japanese native speakers performed a visual sentence comprehension task in which they were asked to read a visually presented sentence…

Target detection using microwave irradiances from natural sources: A passive, local and global surveillance system

NASA Technical Reports Server (NTRS)

Stacey, J. M.

1984-01-01

Detection of metal objects on or near the Earth's surface was investigated using existing, passive, microwave sensors operating from Earth orbit. The range equations are derived from basic microwave principles and theories and the expressions are given explicitly to estimate the signal to noise ratio for detecting metal targets operating as bistatic scatterers. Actual measurements are made on a range of metal objects observed from orbit using existing passive microwave receiving systems. The details of the measurements and the results are tabulated and discussed. The advantages of a passive microwave sensor as it is applied to surveillance of metal objects as viewed from aerial platforms or from orbit, are examined.

Wetland-based passive treatment systems for gold ore processing effluents containing residual cyanide, metals and nitrogen species.

PubMed

Alvarez, R; Ordóñez, A; Loredo, J; Younger, P L

2013-10-01

Gold extraction operations generate a variety of wastes requiring responsible disposal in compliance with current environmental regulations. During recent decades, increased emphasis has been placed on effluent control and treatment, in order to avoid the threat to the environment posed by toxic constituents. In many modern gold mining and ore processing operations, cyanide species are of most immediate concern. Given that natural degradation processes are known to reduce the toxicity of cyanide over time, trials have been made at laboratory and field scales into the feasibility of using wetland-based passive systems as low-cost and environmentally friendly methods for long-term treatment of leachates from closed gold mine tailing disposal facilities. Laboratory experiments on discrete aerobic and anaerobic treatment units supported the development of design parameters for the construction of a field-scale passive system at a gold mine site in northern Spain. An in situ pilot-scale wetland treatment system was designed, constructed and monitored over a nine-month period. Overall, the results suggest that compost-based constructed wetlands are capable of detoxifying cyanidation effluents, removing about 21.6% of dissolved cyanide and 98% of Cu, as well as nitrite and nitrate. Wetland-based passive systems can therefore be considered as a viable technology for removal of residual concentrations of cyanide from leachates emanating from closed gold mine tailing disposal facilities.

Local and Global Auditory Processing: Behavioral and ERP Evidence

PubMed Central

Sanders, Lisa D.; Poeppel, David

2007-01-01

Differential processing of local and global visual features is well established. Global precedence effects, differences in event-related potentials (ERPs) elicited when attention is focused on local versus global levels, and hemispheric specialization for local and global features all indicate that relative scale of detail is an important distinction in visual processing. Observing analogous differential processing of local and global auditory information would suggest that scale of detail is a general organizational principle of the brain. However, to date the research on auditory local and global processing has primarily focused on music perception or on the perceptual analysis of relatively higher and lower frequencies. The study described here suggests that temporal aspects of auditory stimuli better capture the local-global distinction. By combining short (40 ms) frequency modulated tones in series to create global auditory patterns (500 ms), we independently varied whether pitch increased or decreased over short time spans (local) and longer time spans (global). Accuracy and reaction time measures revealed better performance for global judgments and asymmetric interference that were modulated by amount of pitch change. ERPs recorded while participants listened to identical sounds and indicated the direction of pitch change at the local or global levels provided evidence for differential processing similar to that found in ERP studies employing hierarchical visual stimuli. ERP measures failed to provide evidence for lateralization of local and global auditory perception, but differences in distributions suggest preferential processing in more ventral and dorsal areas respectively. PMID:17113115

Results of a Demonstration Assessment of Passive System Reliability Utilizing the Reliability Method for Passive Systems (RMPS)

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

Bucknor, Matthew; Grabaskas, David; Brunett, Acacia

2015-04-26

Advanced small modular reactor designs include many advantageous design features such as passively driven safety systems that are arguably more reliable and cost effective relative to conventional active systems. Despite their attractiveness, a reliability assessment of passive systems can be difficult using conventional reliability methods due to the nature of passive systems. Simple deviations in boundary conditions can induce functional failures in a passive system, and intermediate or unexpected operating modes can also occur. As part of an ongoing project, Argonne National Laboratory is investigating various methodologies to address passive system reliability. The Reliability Method for Passive Systems (RMPS), amore » systematic approach for examining reliability, is one technique chosen for this analysis. This methodology is combined with the Risk-Informed Safety Margin Characterization (RISMC) approach to assess the reliability of a passive system and the impact of its associated uncertainties. For this demonstration problem, an integrated plant model of an advanced small modular pool-type sodium fast reactor with a passive reactor cavity cooling system is subjected to a station blackout using RELAP5-3D. This paper discusses important aspects of the reliability assessment, including deployment of the methodology, the uncertainty identification and quantification process, and identification of key risk metrics.« less

Hydrogen passivation of polycrystalline silicon thin films

NASA Astrophysics Data System (ADS)

Scheller, L.-P.; Weizman, M.; Simon, P.; Fehr, M.; Nickel, N. H.

2012-09-01

The influence of post-hydrogenation on the electrical and optical properties of solid phase crystallized polycrystalline silicon (poly-Si) was examined. The passivation of grain-boundary defects was measured as a function of the passivation time. The silicon dangling-bond concentration decreases with increasing passivation time due to the formation of Si-H complexes. In addition, large H-stabilized platelet-like clusters are generated. The influence of H on the electrical properties was investigated using temperature dependent conductivity and Hall-effect measurements. For poly-Si on Corning glass, the dark conductivity decreases upon hydrogenation, while it increases when the samples are fabricated on silicon-nitride covered Borofloat glass. Hall-effect measurements reveal that for poly-Si on Corning glass the hole concentration and the mobility decrease upon post-hydrogenation, while a pronounced increase is observed for poly-Si on silicon-nitride covered Borofloat glass. This indicates the formation of localized states in the band gap, which is supported by sub band-gap absorption measurments. The results are discussed in terms of hydrogen-induced defect passivation and generation mechanisms.

Superacid Passivation of Crystalline Silicon Surfaces.

PubMed

Bullock, James; Kiriya, Daisuke; Grant, Nicholas; Azcatl, Angelica; Hettick, Mark; Kho, Teng; Phang, Pheng; Sio, Hang C; Yan, Di; Macdonald, Daniel; Quevedo-Lopez, Manuel A; Wallace, Robert M; Cuevas, Andres; Javey, Ali

2016-09-14

The reduction of parasitic recombination processes commonly occurring within the silicon crystal and at its surfaces is of primary importance in crystalline silicon devices, particularly in photovoltaics. Here we explore a simple, room temperature treatment, involving a nonaqueous solution of the superacid bis(trifluoromethane)sulfonimide, to temporarily deactivate recombination centers at the surface. We show that this treatment leads to a significant enhancement in optoelectronic properties of the silicon wafer, attaining a level of surface passivation in line with state-of-the-art dielectric passivation films. Finally, we demonstrate its advantage as a bulk lifetime and process cleanliness monitor, establishing its compatibility with large area photoluminescence imaging in the process.

Design of an HF-Band RFID System with Multiple Readers and Passive Tags for Indoor Mobile Robot Self-Localization

PubMed Central

Mi, Jian; Takahashi, Yasutake

2016-01-01

Radio frequency identification (RFID) technology has already been explored for efficient self-localization of indoor mobile robots. A mobile robot equipped with RFID readers detects passive RFID tags installed on the floor in order to locate itself. The Monte-Carlo localization (MCL) method enables the localization of a mobile robot equipped with an RFID system with reasonable accuracy, sufficient robustness and low computational cost. The arrangements of RFID readers and tags and the size of antennas are important design parameters for realizing accurate and robust self-localization using a low-cost RFID system. The design of a likelihood model of RFID tag detection is also crucial for the accurate self-localization. This paper presents a novel design and arrangement of RFID readers and tags for indoor mobile robot self-localization. First, by considering small-sized and large-sized antennas of an RFID reader, we show how the design of the likelihood model affects the accuracy of self-localization. We also design a novel likelihood model by taking into consideration the characteristics of the communication range of an RFID system with a large antenna. Second, we propose a novel arrangement of RFID tags with eight RFID readers, which results in the RFID system configuration requiring much fewer readers and tags while retaining reasonable accuracy of self-localization. We verify the performances of MCL-based self-localization realized using the high-frequency (HF)-band RFID system with eight RFID readers and a lower density of RFID tags installed on the floor based on MCL in simulated and real environments. The results of simulations and real environment experiments demonstrate that our proposed low-cost HF-band RFID system realizes accurate and robust self-localization of an indoor mobile robot. PMID:27483279

Design of an HF-Band RFID System with Multiple Readers and Passive Tags for Indoor Mobile Robot Self-Localization.

PubMed

Mi, Jian; Takahashi, Yasutake

2016-07-29

Radio frequency identification (RFID) technology has already been explored for efficient self-localization of indoor mobile robots. A mobile robot equipped with RFID readers detects passive RFID tags installed on the floor in order to locate itself. The Monte-Carlo localization (MCL) method enables the localization of a mobile robot equipped with an RFID system with reasonable accuracy, sufficient robustness and low computational cost. The arrangements of RFID readers and tags and the size of antennas are important design parameters for realizing accurate and robust self-localization using a low-cost RFID system. The design of a likelihood model of RFID tag detection is also crucial for the accurate self-localization. This paper presents a novel design and arrangement of RFID readers and tags for indoor mobile robot self-localization. First, by considering small-sized and large-sized antennas of an RFID reader, we show how the design of the likelihood model affects the accuracy of self-localization. We also design a novel likelihood model by taking into consideration the characteristics of the communication range of an RFID system with a large antenna. Second, we propose a novel arrangement of RFID tags with eight RFID readers, which results in the RFID system configuration requiring much fewer readers and tags while retaining reasonable accuracy of self-localization. We verify the performances of MCL-based self-localization realized using the high-frequency (HF)-band RFID system with eight RFID readers and a lower density of RFID tags installed on the floor based on MCL in simulated and real environments. The results of simulations and real environment experiments demonstrate that our proposed low-cost HF-band RFID system realizes accurate and robust self-localization of an indoor mobile robot.

Broadband continuous wave source localization via pair-wise, cochleagram processing

NASA Astrophysics Data System (ADS)

Nosal, Eva-Marie; Frazer, L. Neil

2005-04-01

A pair-wise processor has been developed for the passive localization of broadband continuous-wave underwater sources. The algorithm uses sparse hydrophone arrays and does not require previous knowledge of the source signature. It is applicable in multiple source situations. A spectrogram/cochleagram version of the algorithm has been developed in order to utilize higher frequencies at longer ranges where signal incoherence, and limited computational resources, preclude the use of full waveforms. Simulations demonstrating the robustness of the algorithm with respect to noise and environmental mismatch will be presented, together with initial results from the analysis of humpback whale song recorded at the Pacific Missile Range Facility off Kauai. [Work supported by MHPCC and ONR.

Design of short-range terahertz wave passive detecting system

NASA Astrophysics Data System (ADS)

Zhang, Chao; Lou, Guowei; Zhu, Li; Qian, Songsong; Li, Ting

2016-09-01

Based on the study of radiation and transmission characteristics on THz waveband, a short-range passive detecting system is designed. The scheme originated from microwave passive detecting system. A prototype was developed following the design of key components including antennas and a harmonic mixer. The system operated at 0.36 THz. A dual-beam Cassegrain antenna was adopted for receiving signals which radiated by object and background. Local oscillator signal was generated by frequency multiplication. Harmonic mixing is adopted for reducing local oscillator signal frequency required by half. Superheterodyne technology is employed for signal acquisition. The system implemented easily. Tests and measurements were taken, which showed that the scheme was feasible and the performance of the prototype system met the design requirements.

New analytical solutions for chemical evolution models: characterizing the population of star-forming and passive galaxies

NASA Astrophysics Data System (ADS)

Spitoni, E.; Vincenzo, F.; Matteucci, F.

2017-03-01

Context. Analytical models of chemical evolution, including inflow and outflow of gas, are important tools for studying how the metal content in galaxies evolves as a function of time. Aims: We present new analytical solutions for the evolution of the gas mass, total mass, and metallicity of a galactic system when a decaying exponential infall rate of gas and galactic winds are assumed. We apply our model to characterize a sample of local star-forming and passive galaxies from the Sloan Digital Sky Survey data, with the aim of reproducing their observed mass-metallicity relation. Methods: We derived how the two populations of star-forming and passive galaxies differ in their particular distribution of ages, formation timescales, infall masses, and mass loading factors. Results: We find that the local passive galaxies are, on average, older and assembled on shorter typical timescales than the local star-forming galaxies; on the other hand, the star-forming galaxies with higher masses generally show older ages and longer typical formation timescales compared than star-forming galaxies with lower masses. The local star-forming galaxies experience stronger galactic winds than the passive galaxy population. Exploring the effect of assuming different initial mass functions in our model, we show that to reproduce the observed mass-metallicity relation, stronger winds are requested if the initial mass function is top-heavy. Finally, our analytical models predict the assumed sample of local galaxies to lie on a tight surface in the 3D space defined by stellar metallicity, star formation rate, and stellar mass, in agreement with the well-known fundamental relation from adopting gas-phase metallicity. Conclusions: By using a new analytical model of chemical evolution, we characterize an ensemble of SDSS galaxies in terms of their infall timescales, infall masses, and mass loading factors. Local passive galaxies are, on average, older and assembled on shorter typical

Global processing takes time: A meta-analysis on local-global visual processing in ASD.

PubMed

Van der Hallen, Ruth; Evers, Kris; Brewaeys, Katrien; Van den Noortgate, Wim; Wagemans, Johan

2015-05-01

What does an individual with autism spectrum disorder (ASD) perceive first: the forest or the trees? In spite of 30 years of research and influential theories like the weak central coherence (WCC) theory and the enhanced perceptual functioning (EPF) account, the interplay of local and global visual processing in ASD remains only partly understood. Research findings vary in indicating a local processing bias or a global processing deficit, and often contradict each other. We have applied a formal meta-analytic approach and combined 56 articles that tested about 1,000 ASD participants and used a wide range of stimuli and tasks to investigate local and global visual processing in ASD. Overall, results show no enhanced local visual processing nor a deficit in global visual processing. Detailed analysis reveals a difference in the temporal pattern of the local-global balance, that is, slow global processing in individuals with ASD. Whereas task-dependent interaction effects are obtained, gender, age, and IQ of either participant groups seem to have no direct influence on performance. Based on the overview of the literature, suggestions are made for future research. (c) 2015 APA, all rights reserved).

Joint inversion of active and passive seismic data in Central Java

NASA Astrophysics Data System (ADS)

Wagner, Diana; Koulakov, I.; Rabbel, W.; Luehr, B.-G.; Wittwer, A.; Kopp, H.; Bohm, M.; Asch, G.

2007-08-01

Seismic and volcanic activities in Central Java, Indonesia, the area of interest of this study, are directly or indirectly related to the subduction of the Indo-Australian plate. In the framework of the MERapi AMphibious EXperiments (MERAMEX), a network consisting of about 130 seismographic stations was installed onshore and offshore in Central Java and operated for more than 150 days. In addition, 3-D active seismic experiments were carried out offshore. In this paper, we present the results of processing combined active and passive seismic data, which contain traveltimes from 292 local earthquakes and additional airgun shots along three offshore profiles. The inversion was performed using the updated LOTOS-06 code that allows processing for active and passive source data. The joint inversion of the active and passive data set considerably improves the resolution of the upper crust, especially in the offshore area in comparison to only passive data. The inversion results are verified using a series of synthetic tests. The resulting images show an exceptionally strong low-velocity anomaly (-30 per cent) in the backarc crust northward of the active volcanoes. In the upper mantle beneath the volcanoes, we observe a low-velocity anomaly inclined towards the slab, which probably reflects the paths of fluids and partially melted materials in the mantle wedge. The crust in the forearc appears to be strongly heterogeneous. The onshore part consists of two high-velocity blocks separated by a narrow low-velocity anomaly, which can be interpreted as a weakened contact zone between two rigid crustal bodies. The recent Java Mw = 6.3 earthquake (2006/05/26-UTC) occurred at the lower edge of this zone. Its focal strike slip mechanism is consistent with the orientation of this contact.

An all-silicon passive optical diode.

PubMed

Fan, Li; Wang, Jian; Varghese, Leo T; Shen, Hao; Niu, Ben; Xuan, Yi; Weiner, Andrew M; Qi, Minghao

2012-01-27

A passive optical diode effect would be useful for on-chip optical information processing but has been difficult to achieve. Using a method based on optical nonlinearity, we demonstrate a forward-backward transmission ratio of up to 28 decibels within telecommunication wavelengths. Our device, which uses two silicon rings 5 micrometers in radius, is passive yet maintains optical nonreciprocity for a broad range of input power levels, and it performs equally well even if the backward input power is higher than the forward input. The silicon optical diode is ultracompact and is compatible with current complementary metal-oxide semiconductor processing.

Cost of tobacco-related diseases, including passive smoking, in Hong Kong.

PubMed

McGhee, S M; Ho, L M; Lapsley, H M; Chau, J; Cheung, W L; Ho, S Y; Pow, M; Lam, T H; Hedley, A J

2006-04-01

Costs of tobacco-related disease can be useful evidence to support tobacco control. In Hong Kong we now have locally derived data on the risks of smoking, including passive smoking. To estimate the health-related costs of tobacco from both active and passive smoking. Using local data, we estimated active and passive smoking-attributable mortality, hospital admissions, outpatient, emergency and general practitioner visits for adults and children, use of nursing homes and domestic help, time lost from work due to illness and premature mortality in the productive years. Morbidity risk data were used where possible but otherwise estimates based on mortality risks were used. Utilisation was valued at unit costs or from survey data. Work time lost was valued at the median wage and an additional costing included a value of USD 1.3 million for a life lost. In the Hong Kong population of 6.5 million in 1998, the annual value of direct medical costs, long term care and productivity loss was USD 532 million for active smoking and USD 156 million for passive smoking; passive smoking accounted for 23% of the total costs. Adding the value of attributable lives lost brought the annual cost to USD 9.4 billion. The health costs of tobacco use are high and represent a net loss to society. Passive smoking increases these costs by at least a quarter. This quantification of the costs of tobacco provides strong motivation for legislative action on smoke-free areas in the Asia Pacific Region and elsewhere.

The Effect of Active versus Passive Recovery Periods during High Intensity Intermittent Exercise on Local Tissue Oxygenation in 18 - 30 Year Old Sedentary Men.

PubMed

Kriel, Yuri; Kerhervé, Hugo A; Askew, Christopher D; Solomon, Colin

High intensity interval training (HIIT) has been proposed as a time-efficient format of exercise to reduce the chronic disease burden associated with sedentary behaviour. Changes in oxygen utilisation at the local tissue level during an acute session of HIIT could be the primary stimulus for the health benefits associated with this format of exercise. The recovery periods of HIIT effect the physiological responses that occur during the session. It was hypothesised that in sedentary individuals, local and systemic oxygen utilisation would be higher during HIIT interspersed with active recovery periods, when compared to passive recovery periods. Twelve sedentary males (mean ± SD; age 23 ± 3 yr) completed three conditions on a cycle ergometer: 1) HIIT with passive recovery periods between four bouts (HIITPASS) 2) HIIT with active recovery periods between four bouts (HIITACT) 3) HIITACT with four HIIT bouts replaced with passive periods (REC). Deoxygenated haemoglobin (HHb) in the vastus lateralis (VL) and gastrocnemius (GN) muscles and the pre-frontal cortex (FH), oxygen consumption (VO2), power output and heart rate (HR) were measured continuously during the three conditions. There was a significant increase in HHb at VL during bouts 2 (p = 0.017), 3 (p = 0.035) and 4 (p = 0.035) in HIITACT, compared to HIITPASS. Mean power output was significantly lower in HIITACT, compared to HIITPASS (p < 0.001). There was a significant main effect for site in both HIITPASS (p = 0.029) and HIITACT (p = 0.005). There were no significant differences in VO2 and HR between HIITPASS and HIITACT. The increase in HHb at VL and the lower mean power output during HIITACT could indicate that a higher level of deoxygenation contributes to decreased mechanical power in sedentary participants. The significant differences in HHb between sites indicates the specificity of oxygen utilisation.

Temporal patterning of the potential induced by localized corrosion of iron passivity in acid media. Growth and breakdown of the oxide film described in terms of a point defect model.

PubMed

Sazou, Dimitra; Pavlidou, Maria; Pagitsas, Michael

2009-10-21

This work analyses the nature of temporal patterning of the anodic potential induced by chlorides during polarization of iron under current-controlled conditions in acid solutions. It is shown that potential oscillations emerged as a result of the local chloride attack of a thin oxide layer, which covers the iron surface in its passive state. The mechanism by which both the local oxide breakdown and the subsequent localized active dissolution (pitting) occur is explained by considering a point defect model (PDM) developed to describe the oxide growth and breakdown. According to the PDM, chlorides occupy oxygen vacancies resulting in the inhibition of oxide growth and autocatalytic generation of cation vacancies that destabilize the oxide layer. Simultaneous transformation of the outer surface of the inner oxide layer to non-adherent ferrous chloride or oxo-chloride species leads to a further thinning of the oxide layer and its lifting-on from the iron surface. The process repeats again yielding sustained oscillations of the anodic potential. Analysis of the oscillatory response obtained under current-controlled conditions as a function of either the current or the time allows the suggestion of a set of alternate diagnostic criteria, which might be used to characterize localized corrosion of iron in acid solutions.

Rapid communication: Global-local processing affects recognition of distractor emotional faces.

PubMed

Srinivasan, Narayanan; Gupta, Rashmi

2011-03-01

Recent studies have shown links between happy faces and global, distributed attention as well as sad faces to local, focused attention. Emotions have been shown to affect global-local processing. Given that studies on emotion-cognition interactions have not explored the effect of perceptual processing at different spatial scales on processing stimuli with emotional content, the present study investigated the link between perceptual focus and emotional processing. The study investigated the effects of global-local processing on the recognition of distractor faces with emotional expressions. Participants performed a digit discrimination task with digits at either the global level or the local level presented against a distractor face (happy or sad) as background. The results showed that global processing associated with broad scope of attention facilitates recognition of happy faces, and local processing associated with narrow scope of attention facilitates recognition of sad faces. The novel results of the study provide conclusive evidence for emotion-cognition interactions by demonstrating the effect of perceptual processing on emotional faces. The results along with earlier complementary results on the effect of emotion on global-local processing support a reciprocal relationship between emotional processing and global-local processing. Distractor processing with emotional information also has implications for theories of selective attention.

A simultaneous deep micromachining and surface passivation method suitable for silicon-based devices

NASA Astrophysics Data System (ADS)

Babaei, E.; Gharooni, M.; Mohajerzadeh, S.; Soleimani, E. A.

2018-07-01

Three novel methods for simultaneous micromachining and surface passivation of silicon are reported. A thin passivation layer is achieved using continuous and sequential plasma processes based on SF6, H2 and O2 gases. Reducing the recombination by surface passivation is crucial for the realization of high-performance nanosized optoelectronic devices. The passivation of the surface as an important step, is feasible by plasma processing based on hydrogen pulses in proper time-slots or using a mixture of H2 and O2, and SF6 gases. The passivation layer which is formed in situ during the micromachining process obviates a separate passivation step needed in conventional methods. By adjusting the plasma parameters such as power, duration, and flows of gases, the process can be controlled for the best results and acceptable under-etching at the same time. Moreover, the pseudo-oxide layer which is formed during the micromachining processes will also improve the electrical characteristics of the surface, which can be used as an add-on for micro and nanowire applications. To quantify the effect of surface passivation in our method, ellipsometry, lifetime measurements, x-ray photoelectron spectroscopy, current–voltage and capacitance–voltage measurements and solar cell testing have been employed.

Passive film growth on titanium alloys: physicochemical and biologic considerations.

PubMed

Eliades, T

1997-01-01

The role of reactive oxygen derivatives (hydroxy peroxide, hydroxyl radical, and singlet oxygen) on the precipitation of inorganic and organic complexes onto the surface of titanium implant alloys is discussed in this review. In addition, the effect of possible implication of several biologic entities surrounding the implant on the implant-tissue interface constituents is described. Evidence from relevant studies suggests that local microenvironmental byproducts and factors associated with the inflammatory response resulting from the implant-induced tissue insult may enhance the expressivity of the inherent, clinically important property of titanium to form oxides. Growth of titanium oxide may be explained through several processes derived from biologic, thermodynamic, and electrochemical approaches. The models proposed to interpret this phenomenon are often contradictory, demonstrating inward or outward from the bulk material passive film growth, with increasing or self-limiting levels of oxide formation as a function of time. However, in vivo observations are consistent with aging-induced thickening of the complexes precipitated on the implant material surface. This review attempts to clarify several critical issues pertaining to passive film formation and kinetics on titanium-alloy surfaces.

NASA and ESA Collaboration on Alternative to Nitric Acid Passivation: Parameter Optimization of Citric Acid Passivation for Stainless Steel Alloys

NASA Technical Reports Server (NTRS)

Kessel, Kurt R.

2016-01-01

National Aeronautics and Space Administration (NASA) Headquarters chartered the Technology Evaluation for Environmental Risk Mitigation Principal Center (TEERM) to coordinate agency activities affecting pollution prevention issues identified during system and component acquisition and sustainment processes. The primary objectives of NASA TEERM are to: Reduce or eliminate the use of hazardous materials or hazardous processes at manufacturing, remanufacturing, and sustainment locations. Avoid duplication of effort in actions required to reduce or eliminate hazardous materials through joint center cooperation and technology sharing. Corrosion is an extensive problem that affects the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). The damaging effects of corrosion result in steep costs, asset downtime affecting mission readiness, and safety risks to personnel. Consequently, it is vital to reduce corrosion costs and risks in a sustainable manner. NASA and ESA have numerous structures and equipment that are fabricated from stainless steel. The standard practice for protection of stainless steel is a process called passivation. Passivation is defined by The American Heritage Dictionary of the English Language as to treat or coat (a metal) in order to reduce the chemical reactivity of its surface. Passivation works by forming a shielding outer (metal oxide) layer that reduces the impact of destructive environmental factors such as air or water. Consequently, this process necessitates a final product that is very clean and free of iron and other contaminants. Typical passivation procedures call for the use of nitric acid; however, there are a number of environmental, worker safety, and operational issues associated with its use. Citric acid is an alternative to nitric acid for the passivation of stainless steels. Citric acid offers a variety of benefits including increased safety for personnel, reduced environmental impact, and

Passive electrical monitoring and localization of fluid leakages from wells

NASA Astrophysics Data System (ADS)

Revil, A.; Mao, D.; Haas, A. K.; Karaoulis, M.; Frash, L.

2015-02-01

Electrokinetic phenomena are a class of cross-coupling phenomena involving the relative displacement between the pore water (together with the electrical diffuse layer) with respect to the solid phase of a porous material. We demonstrate that electrical fields of electrokinetic nature can be associated with fluid leakages from wells. These leakages can be remotely monitored and the resulting signals used to localize their causative source distribution both in the laboratory and in field conditions. The first laboratory experiment (Experiment #1) shows how these electrical fields can be recorded at the surface of a cement block during the leakage of a brine from a well. The measurements were performed with a research-grade medical electroencephalograph and were inverted using a genetic algorithm to localize the causative source of electrical current and therefore, localize the leak in the block. Two snapshots of electrical signals were used to show how the leak evolved over time. The second experiment (Experiment #2) was performed to see if we could localize a pulse water injection from a shallow well in field conditions in the case of a heterogeneous subsurface. We used the same equipment as in Experiment #1 and processed the data with a trend removal algorithm, picking the amplitude from 24 receiver channels just after the water injection. The amplitude of the electric signals changed from the background level indicating that a volume of water was indeed flowing inside the well into the surrounding soil and then along the well. We used a least-square inversion algorithm to invert a snapshot of the electrical potential data at the injection time to localize the source of the self-potential signals. The inversion results show positive potential anomalies in the vicinity of the well. For both experiments, forward numerical simulations of the problem using a finite element package were performed in order to assess the underlying physics of the causative source of the

Galaxy And Mass Assembly (GAMA): growing up in a bad neighbourhood - how do low-mass galaxies become passive?

NASA Astrophysics Data System (ADS)

Davies, L. J. M.; Robotham, A. S. G.; Driver, S. P.; Alpaslan, M.; Baldry, I. K.; Bland-Hawthorn, J.; Brough, S.; Brown, M. J. I.; Cluver, M. E.; Holwerda, B. W.; Hopkins, A. M.; Lara-López, M. A.; Mahajan, S.; Moffett, A. J.; Owers, M. S.; Phillipps, S.

2016-02-01

Both theoretical predictions and observations of the very nearby Universe suggest that low-mass galaxies(log10[M*/M⊙] < 9.5) are likely to remain star-forming unless they are affected by their local environment. To test this premise, we compare and contrast the local environment of both passive and star-forming galaxies as a function of stellar mass, using the Galaxy and Mass Assembly survey. We find that passive fractions are higher in both interacting pair and group galaxies than the field at all stellar masses, and that this effect is most apparent in the lowest mass galaxies. We also find that essentially all passive log10[M*/M⊙] < 8.5 galaxies are found in pair/group environments, suggesting that local interactions with a more massive neighbour cause them to cease forming new stars. We find that the effects of immediate environment (local galaxy-galaxy interactions) in forming passive systems increase with decreasing stellar mass, and highlight that this is potentially due to increasing interaction time-scales giving sufficient time for the galaxy to become passive via starvation. We then present a simplistic model to test this premise, and show that given our speculative assumptions, it is consistent with our observed results.

Active nuclear import and passive nuclear export are the primary determinants of TDP-43 localization.

PubMed

Pinarbasi, Emile S; Cağatay, Tolga; Fung, Ho Yee Joyce; Li, Ying C; Chook, Yuh Min; Thomas, Philip J

2018-05-04

ALS (Amyotrophic Lateral Sclerosis) is a neurodegenerative disease characterized by the redistribution of the RNA binding protein TDP-43 in affected neurons: from predominantly nuclear to aggregated in the cytosol. However, the determinants of TDP-43 localization and the cellular insults that promote redistribution are incompletely understood. Here, we show that the putative Nuclear Export Signal (NES) is not required for nuclear egress of TDP-43. Moreover, when the TDP-43 domain which contains the putative NES is fused to a reporter protein, YFP, the presence of the NES is not sufficient to mediate nuclear exclusion of the fusion protein. We find that the previously studied "∆NES" mutant, in which conserved hydrophobic residues are mutated to alanines, disrupts both solubility and splicing function. We further show that nuclear export of TDP-43 is independent of the exportin XPO1. Finally, we provide evidence that nuclear egress of TDP-43 is size dependent; nuclear export of dTomato TDP-43 is significantly impaired compared to Flag TDP-43. Together, these results suggest nuclear export of TDP-43 is predominantly driven by passive diffusion.

Passive sampling for the isotopic fingerprinting of atmospheric mercury

NASA Astrophysics Data System (ADS)

Bergquist, B. A.; MacLagan, D.; Spoznar, N.; Kaplan, R.; Chandan, P.; Stupple, G.; Zimmerman, L.; Wania, F.; Mitchell, C. P. J.; Steffen, A.; Monaci, F.; Derry, L. A.

2017-12-01

Recent studies show that there are variations in the mercury (Hg) isotopic signature of atmospheric Hg, which demonstrates the potential for source tracing and improved understanding of atmospheric cycling of Hg. However, current methods for both measuring atmospheric Hg and collecting enough atmospheric Hg for isotopic analyses require expensive instruments that need power and expertise. Additionally, methods for collecting enough atmospheric Hg for isotopic analysis require pumping air through traps for long periods (weeks and longer). Combining a new passive atmospheric sampler for mercury (Hg) with novel Hg isotopic analyses will allow for the application of stable Hg isotopes to atmospheric studies of Hg. Our group has been testing a new passive sampler for gaseous Hg that relies on the diffusion of Hg through a diffusive barrier and adsorption onto a sulphur-impregnated activated carbon sorbent. The benefit of this passive sampler is that it is low cost, requires no power, and collects gaseous Hg for up to one year with linear, well-defined uptake, which allows for reproducible and accurate measurements of atmospheric gaseous Hg concentrations ( 8% uncertainty). As little as one month of sampling is often adequate to collect sufficient Hg for isotopic analysis at typical background concentrations. Experiments comparing the isotopic Hg signature in activated carbon samples using different approaches (i.e. by passive diffusion, by passive diffusion through diffusive barriers of different thickness, by active pumping) and at different temperatures confirm that the sampling process itself does not impose mass-independent fractionation (MIF). However, sampling does result in a consistent and thus correctable mass-dependent fractionation (MDF) effect. Therefore, the sampler preserves Hg MIF with very high accuracy and precision, which is necessary for atmospheric source tracing, and reasonable MDF can be estimated with some increase in error. In addition to

CVD-Based Valence-Mending Passivation for Crystalline-Si Solar Cells

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

Tao, Meng

2015-03-01

The objective of this project is to investigate a new surface passivation technique, valence-mending passivation, for its applications in crystalline-Si solar cells to achieve significant efficiency improvement and cost reduction. As the enabling technique, the project includes the development of chemical vapor deposition recipes to passivate textured Si(100) and multicrystalline-Si surfaces by sulfur and the characterization of the passivated Si surfaces, including thermal stability, Schottky barrier height, contact resistance and surface recombination. One important application is to replace the Ag finger electrode in Si cells with Al to reduce cost, by ~$0.1/Wp, and allow terawatt-scale deployment of crystalline-Si solar cells.more » These all-Al Si cells require a low-temperature metallization process for the Al electrode, to be compatible with valence-mending passivation and to prevent Al diffusion into n-type Si. Another application is to explore valence-mending passivation of grain boundaries in multicrystalline Si by diffusing sulfur into grain boundaries, to reduce the efficiency gas between monocrystalline-Si solar cells and multicrystalline-Si cells. The major accomplishments of this project include: 1) Demonstration of chemical vapor deposition processes for valence-mending passivation of both monocrystalline Si(100) and multicrystalline Si surfaces. Record Schottky barriers have been demonstrated, with the new record-low barrier of less than 0.08 eV between Al and sulfur-passivated n-type Si(100) and the new record-high barrier of 1.14 eV between Al and sulfur-passivated p-type Si(100). On the textured p-type monocrystalline Si(100) surface, the highest barrier with Al is 0.85 eV by valence-mending passivation. 2) Demonstration of a low-temperature metallization process for Al in crystalline-Si solar cells. The new metallization process is based on electroplating of Al in a room-temperature ionic liquid. The resistivity of the electroplated Al is ~7�

Improvement of bias-stability in amorphous-indium-gallium-zinc-oxide thin-film transistors by using solution-processed Y{sub 2}O{sub 3} passivation

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

An, Sungjin; Mativenga, Mallory; Kim, Youngoo

2014-08-04

We demonstrate back channel improvement of back-channel-etch amorphous-indium-gallium-zinc-oxide (a-IGZO) thin-film transistors by using solution-processed yttrium oxide (Y{sub 2}O{sub 3}) passivation. Two different solvents, which are acetonitrile (35%) + ethylene glycol (65%), solvent A and deionized water, solvent B are investigated for the spin-on process of the Y{sub 2}O{sub 3} passivation—performed after patterning source/drain (S/D) Mo electrodes by a conventional HNO{sub 3}-based wet-etch process. Both solvents yield devices with good performance but those passivated by using solvent B exhibit better light and bias stability. Presence of yttrium at the a-IGZO back interface, where it occupies metal vacancy sites, is confirmed by X-ray photoelectronmore » spectroscopy. The passivation effect of yttrium is more significant when solvent A is used because of the existence of more metal vacancies, given that the alcohol (65% ethylene glycol) in solvent A may dissolve the metal oxide (a-IGZO) through the formation of alkoxides and water.« less

Cross-coherent vector sensor processing for spatially distributed glider networks.

PubMed

Nichols, Brendan; Sabra, Karim G

2015-09-01

Autonomous underwater gliders fitted with vector sensors can be used as a spatially distributed sensor array to passively locate underwater sources. However, to date, the positional accuracy required for robust array processing (especially coherent processing) is not achievable using dead-reckoning while the gliders remain submerged. To obtain such accuracy, the gliders can be temporarily surfaced to allow for global positioning system contact, but the acoustically active sea surface introduces locally additional sensor noise. This letter demonstrates that cross-coherent array processing, which inherently mitigates the effects of local noise, outperforms traditional incoherent processing source localization methods for this spatially distributed vector sensor network.

The Role of Organ of Corti Mass in Passive Cochlear Tuning

PubMed Central

de La Rochefoucauld, Ombeline; Olson, Elizabeth S.

2007-01-01

The mechanism for passive cochlear tuning remains unsettled. Early models considered the organ of Corti complex (OCC) as a succession of spring-mass resonators. Later, traveling wave models showed that passive tuning could arise through the interaction of cochlear fluid mass and OCC stiffness without local resonators. However, including enough OCC mass to produce local resonance enhanced the tuning by slowing and thereby growing the traveling wave as it approached its resonant segment. To decide whether the OCC mass plays a role in tuning, the frequency variation of the wavenumber of the cochlear traveling wave was measured (in vivo, passive cochleae) and compared to theoretical predictions. The experimental wavenumber was found by taking the phase difference of basilar membrane motion between two longitudinally spaced locations and dividing by the distance between them. The theoretical wavenumber was a solution of the dispersion relation of a three-dimensional cochlear model with OCC mass and stiffness as the free parameters. The experimental data were only well fit by a model that included OCC mass. However, as the measurement position moved from a best-frequency place of 40 to 12 kHz, the role of mass was diminished. The notion of local resonance seems to only apply in the very high-frequency region of the cochlea. PMID:17905841

Passive sampling of DDT, DDE and DDD in sediments: accounting for degradation processes with reaction-diffusion modeling.

PubMed

Tcaciuc, A Patricia; Borrelli, Raffaella; Zaninetta, Luciano M; Gschwend, Philip M

2018-01-24

Passive sampling is becoming a widely used tool for assessing freely dissolved concentrations of hydrophobic organic contaminants in environmental media. For certain media and target analytes, the time to reach equilibrium exceeds the deployment time, and in such cases, the loss of performance reference compounds (PRCs), loaded in the sampler before deployment, is one of the common ways used to assess the fractional equilibration of target analytes. The key assumption behind the use of PRCs is that their release is solely diffusion driven. But in this work, we show that PRC transformations in the sediment can have a measurable impact on the PRC releases and even allow estimation of that compound's transformation rate in the environment of interest. We found that in both field and lab incubations, the loss of the 13 C 2,4'-DDT PRC from a polyethylene (PE) passive sampler deployed at the sediment-water interface was accelerated compared to the loss of other PRCs ( 13 C-labeled PCBs, 13 C-labeled DDE and DDD). The DDT PRC loss was also accompanied by accumulation in the PE of its degradation product, 13 C 2,4'-DDD. Using a 1D reaction-diffusion model, we deduced the in situ degradation rates of DDT from the measured PRC loss. The in situ degradation rates increased with depth into the sediment bed (0.14 d -1 at 0-10 cm and 1.4 d -1 at 30-40 cm) and although they could not be independently validated, these rates compared favorably with literature values. This work shows that passive sampling users should be cautious when choosing PRCs, as degradation processes can affect some PRC's releases from the passive sampler. More importantly, this work opens up the opportunity for novel applications of passive samplers, particularly with regard to investigating in situ degradation rates, pathways, and products for both legacy and emerging contaminants. However, further work is needed to confirm that the rates deduced from model fitting of PRC loss are a true reflection of DDT

A passive solar residence using native and recycled materials, Bee Cave, Texas

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

Holder, L.M. III; King, L.H.

The Booth Residence at Bee Cave, Texas is a Passive Solar residence in a hot humid climate and a good example of both passive solar and renewable features. The design, operation, materials, and furnishings give the structure a regional and rustic character. Passive solar strategies employed include solar orientation, solar shading, natural ventilation, induced ventilation, night flushing, direct gain clearstory, high mass floors, daylighting, radiant barrier, and a double ventilated roof system. The project is in contrast to the existing compound which includes three identical buildings each rotated 120 degrees and intended to be energy efficient, but actual operation hasmore » pointed out some deficiencies in the design. Additional features include extensive use of natural, recycled, and materials reused from other buildings. The Boothe Residence is an example of building in harmony with the local climate, the use of locally available materials, craftsman, artists, manpower, and reuse of trim and furnishings.« less

Southern Mariana OBS Experiment and Preliminary Results of Passive-Source Investigations

NASA Astrophysics Data System (ADS)

Le, B. M.; Lin, J.; Yang, T.; Shiyan 3, S. P. O. R.

2017-12-01

The Southern Mariana OBS Experiment (SMOE) was one of the first seismic experiments targeting the deepest part of Earth's surface. During the Phase I experiment in December 2016, an array of OBS instruments were deployed across the Challenger Deep that recorded both active-source and passive-source data. During the Phase II experiment in December 2016-June 2017, passive-source data were recorded. We have retrieved earthquake signals and processed the waveforms from the recorded global, regional and local events, respectively, during the Phase I experiment. Most of the waveforms recorded by the OBS array have fairly good quality with discernible main phases. Rayleigh waves from many earthquakes were analyzed using the frequency-time analysis and their group velocities at different periods were obtained. The dispersion curves from different Rayleigh wave propagating paths would be valuable for inverting the structure of the subducting Pacific and overriding Philippine Sea plates. Furthermore, we applied the ambient noise cross-correlation method and retrieved high-quality coherence surface wave waveforms. With its relatively high frequencies, the surface waves can be used to study the crustal structure of the region. Together with the Phase II data, we expect that this seismic experiment will provide unprecedented constraints on the structure and geodynamic processes of the southern Mariana trench.

Demonstration of Passive Fuel Cell Thermal Management Technology

NASA Technical Reports Server (NTRS)

Burke, Kenneth A.; Jakupca, Ian; Colozza, Anthony; Wynne, Robert; Miller, Michael; Meyer, Al; Smith, William

2012-01-01

The NASA Glenn Research Center is developing advanced passive thermal management technology to reduce the mass and improve the reliability of space fuel cell systems for the NASA Exploration program. The passive thermal management system relies on heat conduction within highly thermally conductive cooling plates to move the heat from the central portion of the cell stack out to the edges of the fuel cell stack. Using the passive approach eliminates the need for a coolant pump and other cooling loop components within the fuel cell system which reduces mass and improves overall system reliability. Previous development demonstrated the performance of suitable highly thermally conductive cooling plates and integrated heat exchanger technology to collect the heat from the cooling plates (Ref. 1). The next step in the development of this passive thermal approach was the demonstration of the control of the heat removal process and the demonstration of the passive thermal control technology in actual fuel cell stacks. Tests were run with a simulated fuel cell stack passive thermal management system outfitted with passive cooling plates, an integrated heat exchanger and two types of cooling flow control valves. The tests were run to demonstrate the controllability of the passive thermal control approach. Finally, successful demonstrations of passive thermal control technology were conducted with fuel cell stacks from two fuel cell stack vendors.

Experimental studies of high-accuracy RFID localization with channel impairments

NASA Astrophysics Data System (ADS)

Pauls, Eric; Zhang, Yimin D.

2015-05-01

Radio frequency identification (RFID) systems present an incredibly cost-effective and easy-to-implement solution to close-range localization. One of the important applications of a passive RFID system is to determine the reader position through multilateration based on the estimated distances between the reader and multiple distributed reference tags obtained from, e.g., the received signal strength indicator (RSSI) readings. In practice, the achievable accuracy of passive RFID reader localization suffers from many factors, such as the distorted RSSI reading due to channel impairments in terms of the susceptibility to reader antenna patterns and multipath propagation. Previous studies have shown that the accuracy of passive RFID localization can be significantly improved by properly modeling and compensating for such channel impairments. The objective of this paper is to report experimental study results that validate the effectiveness of such approaches for high-accuracy RFID localization. We also examine a number of practical issues arising in the underlying problem that limit the accuracy of reader-tag distance measurements and, therefore, the estimated reader localization. These issues include the variations in tag radiation characteristics for similar tags, effects of tag orientations, and reader RSS quantization and measurement errors. As such, this paper reveals valuable insights of the issues and solutions toward achieving high-accuracy passive RFID localization.

Side-wall spacer passivated sub-μm Josephson junction fabrication process

NASA Astrophysics Data System (ADS)

Grönberg, Leif; Kiviranta, Mikko; Vesterinen, Visa; Lehtinen, Janne; Simbierowicz, Slawomir; Luomahaara, Juho; Prunnila, Mika; Hassel, Juha

2017-12-01

We present a structure and a fabrication method for superconducting tunnel junctions down to the dimensions of 200 nm using i-line UV lithography. The key element is a sidewall-passivating spacer structure (SWAPS) which is shaped for smooth crossline contacting and low parasitic capacitance. The SWAPS structure enables formation of junctions with dimensions at or below the lithography-limited linewidth. An additional benefit is avoiding the excessive use of amorphous dielectric materials which is favorable in sub-Kelvin microwave applications often plagued by nonlinear and lossy dielectrics. We apply the structure to niobium trilayer junctions, and provide characterization results yielding evidence on wafer-scale scalability, and critical current density tuning in the range of 0.1-3.0 kA cm-2. We discuss the applicability of the junction process in the context of different applications, such as SQUID magnetometers and Josephson parametric amplifiers.

Improvements to Passive Acoustic Tracking Methods for Marine Mammal Monitoring

DTIC Science & Technology

2016-05-02

individual animals . 15. SUBJECT TERMS Marine mammal; Passive acoustic monitoring ; Localization; Tracking ; Multiple source ; Sparse array 16. SECURITY...al. 2004; Thode 2005; Nosal 2007] to localize animals in situations where straight-line propagation assumptions made by conventional marine mammal...Objective 1: Inveti for sound speed profiles. hydrophone position and hydrophone timing offset in addition to animal position Almost all marine mammal

Improvements to Passive Acoustic Tracking Methods for Marine Mammal Monitoring

DTIC Science & Technology

2016-05-02

separate and associate calls from individual animals . Marine mammal; Passive acoustic monitoring; Localization; Tracking; Multiple source; Sparse array...position and hydrophone timing offset in addition to animal position Almost all marine mammal tracking methods treat animal position as the only unknown...Workshop on Detection, Classification and Localization (DCL) of Marine Mammals). The animals were expected to be relatively close to the surface

Do two and three year old children use an incremental first-NP-as-agent bias to process active transitive and passive sentences?: A permutation analysis

PubMed Central

Chang, Franklin; Rowland, Caroline; Ferguson, Heather; Pine, Julian

2017-01-01

We used eye-tracking to investigate if and when children show an incremental bias to assume that the first noun phrase in a sentence is the agent (first-NP-as-agent bias) while processing the meaning of English active and passive transitive sentences. We also investigated whether children can override this bias to successfully distinguish active from passive sentences, after processing the remainder of the sentence frame. For this second question we used eye-tracking (Study 1) and forced-choice pointing (Study 2). For both studies, we used a paradigm in which participants simultaneously saw two novel actions with reversed agent-patient relations while listening to active and passive sentences. We compared English-speaking 25-month-olds and 41-month-olds in between-subjects sentence structure conditions (Active Transitive Condition vs. Passive Condition). A permutation analysis found that both age groups showed a bias to incrementally map the first noun in a sentence onto an agent role. Regarding the second question, 25-month-olds showed some evidence of distinguishing the two structures in the eye-tracking study. However, the 25-month-olds did not distinguish active from passive sentences in the forced choice pointing task. In contrast, the 41-month-old children did reanalyse their initial first-NP-as-agent bias to the extent that they clearly distinguished between active and passive sentences both in the eye-tracking data and in the pointing task. The results are discussed in relation to the development of syntactic (re)parsing. PMID:29049390

Solution-processed gadolinium doped indium-oxide thin-film transistors with oxide passivation

NASA Astrophysics Data System (ADS)

Lee, Seung-Hun; Kim, Taehun; Lee, Jihun; Avis, Christophe; Jang, Jin

2017-03-01

We studied the effect of Gd doping on the structural properties of solution processed, crystalline In2O3 for thin-film transistor (TFT) application. With increasing Gd in In2O3 up to 20%, the material structure changes into amorphous phase, and the oxygen vacancy concentration decreases from 15.4 to 8.4%, and M-OH bonds from 33.5 to 23.7%. The field-effect mobility for the Gd doped In2O3 TFTs decreases and threshold voltage shifts to the positive voltage with increasing Gd concentration. In addition, the stability of the solution processed TFTs can also be improved by increasing Gd concentration. As a result, the optimum Gd concentration is found to be ˜5% in In2O3 and the 5% Gd doped In2O3 TFTs with the Y2O3 passivation layer exhibit the linear mobility of 9.74 cm2/V s, the threshold voltage of -0.27 V, the subthreshold swing of 79 mV/dec., and excellent bias stability.

Passive solar design strategies: Remodeling guidelines for conserving energy at home

NASA Astrophysics Data System (ADS)

The idea of passive solar is simple, but applying it effectively does require information and attention to the details of design and construction. Some passive solar techniques are modest and low-cost, and require only small changes in remodeler's typical practice. At the other end of the spectrum, some passive solar systems can almost eliminate a house's need for purchased heating (and in some cases, cooling) energy - but probably at a relatively high first cost. In between are a broad range of energy-conserving passive solar techniques. Whether or not they are cost-effective, practical, and attractive enough to offer a market advantage to any individual remodeler depends on very specific factors such as local costs, climate, and market characteristics. Passive Solar Design Strategies: Remodeling Guidelines For Conserving Energy At Home is written to help give remodelers the information they need to make these decisions. Passive Solar Design Strategies is a package in three basic parts: the guidelines contain information about passive solar techniques and how they work, and provides specific examples of systems which will save various percentages of energy; the worksheets offer a simple, fill-in-the-blank method to pre-evaluate the performance of a specific design; and the worked example demonstrates how to complete the worksheets for a typical residence.

Surface Passivation for 3-5 Semiconductor Processing: Stable Gallium Sulphide Films by MOCVD

NASA Technical Reports Server (NTRS)

Macinnes, Andrew N.; Jenkins, Phillip P.; Power, Michael B.; Kang, Soon; Barron, Andrew R.; Hepp, Aloysius F.; Tabib-Azar, Massood

1994-01-01

Gallium sulphide (GaS) has been deposited on GaAs to form stable, insulating, passivating layers. Spectrally resolved photoluminescence and surface recombination velocity measurements indicate that the GaS itself can contribute a significant fraction of the photoluminescence in GaS/GaAs structures. Determination of surface recombination velocity by photoluminescence is therefore difficult. By using C-V analysis of metal-insulator-semiconductor structures, passivation of the GaAs with GaS films is quantified.

Word Order and Linguistic Factors in the Second Language Processing of Spanish Passive Sentences

ERIC Educational Resources Information Center

Lee, James F.

2017-01-01

The present study examines how second language learners (L2) assign the thematic roles of agent/patient in Spanish passive sentences with "ser" (often referred to as the true passive) when it is their initial exposure to this structure. The target sentences were preceded by a contextual sentence. After hearing the two sentences,…

Alternative to Nitric Acid for Passivation of Stainless Steel Alloys

NASA Technical Reports Server (NTRS)

Lewis, Pattie L.; Kolody, Mark; Curran, Jerry

2013-01-01

Corrosion is an extensive problem that affects the Department of Defense (DoD) and National Aeronautics and Space Administration (NASA). The deleterious effects of corrosion result in steep costs, asset downtime affecting mission readiness, and safety risks to personnel. Consequently, it is vital to reduce corrosion costs and risks in a sustainable manner. The DoD and NASA have numerous structures and equipment that are fabricated from stainless steel. The standard practice for protection of stainless steel is a process called passivation. Typical passivation procedures call for the use of nitric acid; however, there are a number of environmental, worker safety, and operational issues associated with its use. Citric acid offers a variety of benefits including increased safety for personnel, reduced environmental impact, and reduced operational cost. DoD and NASA agreed to collaborate to validate citric acid as an acceptable passivating agent for stainless steel. This paper details our investigation of prior work developing the citric acid passivation process, development of the test plan, optimization of the process for specific stainless steel alloys, ongoing and planned testing to elucidate the process' resistance to corrosion in comparison to nitric acid, and preliminary results.

Plants for passive cooling. A preliminary investigation of the use of plants for passive cooling in temperate humid climates

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

Spirn, A W; Santos, A N; Johnson, D A

1981-04-01

The potential of vegetation for cooling small, detached residential and commercial structures in temperate, humid climates is discussed. The results of the research are documented, a critical review of the literature is given, and a brief review of energy transfer processes is presented. A checklist of design objectives for passive cooling, a demonstration of design applications, and a palette of selected plant species suitable for passive cooling are included.

ESAC RFI Survey in the SMOS 1400-1427MHz Passive Band

NASA Astrophysics Data System (ADS)

Castillo-Fraile, Manuel; Uranga, Ekhi

2016-08-01

The SMOS (Soil Moisture and Ocean Salinity) satellite was launched on 2 November 2009, and it is the ESA second Earth Explorer Opportunity mission. After 6 years of successful Operations, the status of the SMOS mission is excellent, and it is providing very reliable acquisition, nominal and NRT data processing, archiving, and dissemination services of Level 1 and Level 2 processed data around the entire Planet. However, SMOS observations are significantly affected by RF interferences in several World areas. In this context, a new RFI detection and monitoring tool has been implemented at ESAC to provide to the national radiofrequency authorities with a proper detection and localization method of the illegal ground emitters in order to ensure the protection of the SMOS 1400- 1427MHz Passive Band for scientific applications.

Upstream vertical cavity surface-emitting lasers for fault monitoring and localization in WDM passive optical networks

NASA Astrophysics Data System (ADS)

Wong, Elaine; Zhao, Xiaoxue; Chang-Hasnain, Connie J.

2008-04-01

As wavelength division multiplexed passive optical networks (WDM-PONs) are expected to be first deployed to transport high capacity services to business customers, real-time knowledge of fiber/device faults and the location of such faults will be a necessity to guarantee reliability. Nonetheless, the added benefit of implementing fault monitoring capability should only incur minimal cost associated with upgrades to the network. In this work, we propose and experimentally demonstrate a fault monitoring and localization scheme based on a highly-sensitive and potentially low-cost monitor in conjunction with vertical cavity surface-emitting lasers (VCSELs). The VCSELs are used as upstream transmitters in the WDM-PON. The proposed scheme benefits from the high reflectivity of the top distributed Bragg reflector (DBR) mirror of optical injection-locked (OIL) VCSELs to reflect monitoring channels back to the central office for monitoring. Characterization of the fault monitor demonstrates high sensitivity, low bandwidth requirements, and potentially low output power. The added advantage of the proposed fault monitoring scheme incurs only a 0.5 dB penalty on the upstream transmissions on the existing infrastructure.

Passive fire building protection system evaluation (case study: millennium ict centre)

NASA Astrophysics Data System (ADS)

Rahman, Vinky; Stephanie

2018-03-01

Passive fire protection system is a system that refers to the building design, both regarding of architecture and structure. This system usually consists of structural protection that protects the structure of the building and prevents the spread of fire and facilitate the evacuation process in case of fire. Millennium ICT Center is the largest electronic shopping center in Medan, Indonesia. As a public building that accommodates the crowd, this building needs a fire protection system by the standards. Therefore, the purpose of this study is to evaluate passive fire protection system of Millennium ICT Center building. The study was conducted to describe the facts of the building as well as direct observation to the research location. The collected data is then processed using the AHP (Analytical Hierarchy Process) method in its weighting process to obtain the reliability value of passive fire protection fire system. The results showed that there are some components of passive fire protection system in the building, but some are still unqualified. The first section in your paper

The Comparative Effects of Processing Instruction and Dictogloss on the Acquisition of the English Passive by Speakers of Turkish

ERIC Educational Resources Information Center

Uludag, Onur; Vanpatten, Bill

2012-01-01

The current study presents the results of an experiment investigating the effects of processing instruction (PI) and dictogloss (DG) on the acquisition of the English passive voice. Sixty speakers of Turkish studying English at university level were assigned to three groups: one receiving PI, the other receiving DG and the third serving as a…

Structures and Intermittency in a Passive Scalar Model

NASA Astrophysics Data System (ADS)

Vergassola, M.; Mazzino, A.

1997-09-01

Perturbative expansions for intermittency scaling exponents in the Kraichnan passive scalar model [Phys. Rev. Lett. 72, 1016 (1994)] are investigated. A one-dimensional compressible model is considered for this purpose. High resolution Monte Carlo simulations using an Ito approach adapted to an advecting velocity field with a very short correlation time are performed and lead to clean scaling behavior for passive scalar structure functions. Perturbative predictions for the scaling exponents around the Gaussian limit of the model are derived as in the Kraichnan model. Their comparison with the simulations indicates that the scale-invariant perturbative scheme correctly captures the inertial range intermittency corrections associated with the intense localized structures observed in the dynamics.

Enhancing Stability of Perovskite Solar Cells to Moisture by the Facile Hydrophobic Passivation.

PubMed

Hwang, Insung; Jeong, Inyoung; Lee, Jinwoo; Ko, Min Jae; Yong, Kijung

2015-08-12

In this study, a novel and facile passivation process for a perovskite solar cell is reported. Poor stability in ambient atmosphere, which is the most critical demerit of a perovskite solar cell, is overcome by a simple passivation process using a hydrophobic polymer layer. Teflon, the hydrophobic polymer, is deposited on the top of a perovskite solar cell by a spin-coating method. With the hydrophobic passivation, the perovskite solar cell shows negligible degradation after a 30 day storage in ambient atmosphere. Suppressed degradation of the perovskite film is proved in various ways: X-ray diffraction, light absorption spectrum, and quartz crystal microbalance. This simple but effective passivation process suggests new kind of approach to enhance stability of perovskite solar cells to moisture.

Global-local processing relates to spatial and verbal processing: implications for sex differences in cognition.

PubMed

Pletzer, Belinda; Scheuringer, Andrea; Scherndl, Thomas

2017-09-05

Sex differences have been reported for a variety of cognitive tasks and related to the use of different cognitive processing styles in men and women. It was recently argued that these processing styles share some characteristics across tasks, i.e. male approaches are oriented towards holistic stimulus aspects and female approaches are oriented towards stimulus details. In that respect, sex-dependent cognitive processing styles share similarities with attentional global-local processing. A direct relationship between cognitive processing and global-local processing has however not been previously established. In the present study, 49 men and 44 women completed a Navon paradigm and a Kimchi Palmer task as well as a navigation task and a verbal fluency task with the goal to relate the global advantage (GA) effect as a measure of global processing to holistic processing styles in both tasks. Indeed participants with larger GA effects displayed more holistic processing during spatial navigation and phonemic fluency. However, the relationship to cognitive processing styles was modulated by the specific condition of the Navon paradigm, as well as the sex of participants. Thus, different types of global-local processing play different roles for cognitive processing in men and women.

Passivation layer breakdown during laser-fired contact formation for photovoltaic devices

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

Raghavan, A.; DebRoy, T.; Palmer, T. A.

2014-07-14

Low resistance laser-fired ohmic contacts (LFCs) can be formed on the backside of Si-based solar cells using microsecond pulses. However, the impact of these longer pulse durations on the dielectric passivation layer is not clear. Retention of the passivation layer during processing is critical to ensure low recombination rates of electron-hole pairs at the rear surface of the device. In this work, advanced characterization tools are used to demonstrate that although the SiO{sub 2} passivation layer melts directly below the laser, it is well preserved outside the immediate LFC region over a wide range of processing parameters. As a result,more » low recombination rates at the passivation layer/wafer interface can be expected despite higher energy densities associated with these pulse durations.« less

Three-Dimensional Numerical Simulation on Passively Excited Flows by Distributed Local Hot Sources Settled at the D" Layer Below Hotspots and/or Large-Scale Cool Masses at Subduction Zones Within the Static Layered Mantle

NASA Astrophysics Data System (ADS)

Eguchi, T.; Matsubara, K.; Ishida, M.

2001-12-01

To unveil dynamic process associated with three-dimensional unsteady mantle convection, we carried out numerical simulation on passively exerted flows by simplified local hot sources just above the CMB and large-scale cool masses beneath smoothed subduction zones. During the study, we used our individual code developed with the finite difference method. The basic three equations are for the continuity, the motion with the Boussinesq (incompressible) approximation, and the (thermal) energy conservation. The viscosity of our model is sensitive to temperature. To get time integration with high precision, we used the Newton method. In detail, the size and thermal energy of the hot or cool sources are not uniform along the latitude, because we could not select uniform local volumes assigned for the sources within the finite difference grids throughout the mantle. Our results, thus, accompany some latitude dependence. First, we treated the case of the hotspots, neglecting the contribution of the subduction zones. The local hot sources below the currently active hotspots were settled as dynamic driving forces included in the initial condition. Before starting the calculation, we assumed that the mantle was statically layered with zero velocity component. The thermal anomalies inserted instantaneously in the initial condition do excite dynamically passive flows. The type of the initial hot sources was not 'plume' but 'thermal.' The simulation results represent that local upwelling flows which were directly excited over the initial heat sources reached the upper mantle by approximately 30 My during the calculation. Each of the direct upwellings above the hotspots has its own dynamic potential to exert concentric down- and up-welling flows, alternately, at large distances. Simultaneously, the direct upwellings interact mutually within the spherical mantle. As an interesting feature, we numerically observed secondary upwellings somewhere in a wide region covering east Eurasia

Assessing the robustness of passive scattering proton therapy with regard to local recurrence in stage III non-small cell lung cancer: a secondary analysis of a phase II trial.

PubMed

Zhu, Zhengfei; Liu, Wei; Gillin, Michael; Gomez, Daniel R; Komaki, Ritsuko; Cox, James D; Mohan, Radhe; Chang, Joe Y

2014-05-06

We assessed the robustness of passive scattering proton therapy (PSPT) plans for patients in a phase II trial of PSPT for stage III non-small cell lung cancer (NSCLC) by using the worst-case scenario method, and compared the worst-case dose distributions with the appearance of locally recurrent lesions. Worst-case dose distributions were generated for each of 9 patients who experienced recurrence after concurrent chemotherapy and PSPT to 74 Gy(RBE) for stage III NSCLC by simulating and incorporating uncertainties associated with set-up, respiration-induced organ motion, and proton range in the planning process. The worst-case CT scans were then fused with the positron emission tomography (PET) scans to locate the recurrence. Although the volumes enclosed by the prescription isodose lines in the worst-case dose distributions were consistently smaller than enclosed volumes in the nominal plans, the target dose coverage was not significantly affected: only one patient had a recurrence outside the prescription isodose lines in the worst-case plan. PSPT is a relatively robust technique. Local recurrence was not associated with target underdosage resulting from estimated uncertainties in 8 of 9 cases.

Quantitative Frequency-Domain Passive Cavitation Imaging

PubMed Central

Haworth, Kevin J.; Bader, Kenneth B.; Rich, Kyle T.; Holland, Christy K.; Mast, T. Douglas

2017-01-01

Passive cavitation detection has been an instrumental technique for measuring cavitation dynamics, elucidating concomitant bioeffects, and guiding ultrasound therapies. Recently, techniques have been developed to create images of cavitation activity to provide investigators with a more complete set of information. These techniques use arrays to record and subsequently beamform received cavitation emissions, rather than processing emissions received on a single-element transducer. In this paper, the methods for performing frequency-domain delay, sum, and integrate passive imaging are outlined. The method can be applied to any passively acquired acoustic scattering or emissions, including cavitation emissions. In order to compare data across different systems, techniques for normalizing Fourier transformed data and converting the data to the acoustic energy received by the array are described. A discussion of hardware requirements and alternative imaging approaches are additionally outlined. Examples are provided in MATLAB. PMID:27992331

Auditory global-local processing: effects of attention and musical experience.

PubMed

Ouimet, Tia; Foster, Nicholas E V; Hyde, Krista L

2012-10-01

In vision, global (whole) features are typically processed before local (detail) features ("global precedence effect"). However, the distinction between global and local processing is less clear in the auditory domain. The aims of the present study were to investigate: (i) the effects of directed versus divided attention, and (ii) the effect musical training on auditory global-local processing in 16 adult musicians and 16 non-musicians. Participants were presented with short nine-tone melodies, each comprised of three triplet sequences (three-tone units). In a "directed attention" task, participants were asked to focus on either the global or local pitch pattern and had to determine if the pitch pattern went up or down. In a "divided attention" task, participants judged whether the target pattern (up or down) was present or absent. Overall, global structure was perceived faster and more accurately than local structure. The global precedence effect was observed regardless of whether attention was directed to a specific level or divided between levels. Musicians performed more accurately than non-musicians overall, but non-musicians showed a more pronounced global advantage. This study provides evidence for an auditory global precedence effect across attention tasks, and for differences in auditory global-local processing associated with musical experience.

Passive Impact Damage Detection of Fiber Glass Composite Panels

DTIC Science & Technology

2013-12-19

PASSIVE IMPACT DAMAGE DETECTION OF FIBER GLASS COMPOSITE PANELS. By BRUNO ZAMORANO-SENDEROS A dissertation...COVERED 04-11-2012 to 10-12-2013 4. TITLE AND SUBTITLE PASSIVE IMPACT DAMAGE DETECTION OF FIBER GLASS COMPOSITE PANELS 5a. CONTRACT NUMBER 5b...process. .................................... 31 Figure 3-8 Sensor attached to the fiber glass fabric

[Investigation on remote measurement of air pollution by a method of infrared passive scanning imaging].

PubMed

Jiao, Yang; Xu, Liang; Gao, Min-Guang; Feng, Ming-Chun; Jin, Ling; Tong, Jing-Jing; Li, Sheng

2012-07-01

Passive remote sensing by Fourier-transform infrared (FTIR) spectrometry allows detection of air pollution. However, for the localization of a leak and a complete assessment of the situation in the case of the release of a hazardous cloud, information about the position and the distribution of a cloud is essential. Therefore, an imaging passive remote sensing system comprising an interferometer, a data acquisition and processing software, scan system, a video system, and a personal computer has been developed. The remote sensing of SF6 was done. The column densities of all directions in which a target compound has been identified may be retrieved by a nonlinear least squares fitting algorithm and algorithm of radiation transfer, and a false color image is displayed. The results were visualized by a video image, overlaid by false color concentration distribution image. The system has a high selectivity, and allows visualization and quantification of pollutant clouds.

Teflon/SiO₂ Bilayer Passivation for Improving the Electrical Reliability of Oxide TFTs Fabricated Using a New Two-Photomask Self-Alignment Process.

PubMed

Fan, Ching-Lin; Shang, Ming-Chi; Li, Bo-Jyun; Lin, Yu-Zuo; Wang, Shea-Jue; Lee, Win-Der; Hung, Bohr-Ran

2015-04-13

This study proposes a two-photomask process for fabricating amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) that exhibit a self-aligned structure. The fabricated TFTs, which lack etching-stop (ES) layers, have undamaged a-IGZO active layers that facilitate superior performance. In addition, we demonstrate a bilayer passivation method that uses a polytetrafluoroethylene (Teflon) and SiO₂ combination layer for improving the electrical reliability of the fabricated TFTs. Teflon was deposited as a buffer layer through thermal evaporation. The Teflon layer exhibited favorable compatibility with the underlying IGZO channel layer and effectively protected the a-IGZO TFTs from plasma damage during SiO₂ deposition, resulting in a negligible initial performance drop in the a-IGZO TFTs. Compared with passivation-free a-IGZO TFTs, passivated TFTs exhibited superior stability even after 168 h of aging under ambient air at 95% relative humidity.

Passive language mapping combining real-time oscillation analysis with cortico-cortical evoked potentials for awake craniotomy.

PubMed

Tamura, Yukie; Ogawa, Hiroshi; Kapeller, Christoph; Prueckl, Robert; Takeuchi, Fumiya; Anei, Ryogo; Ritaccio, Anthony; Guger, Christoph; Kamada, Kyousuke

2016-12-01

OBJECTIVE Electrocortical stimulation (ECS) is the gold standard for functional brain mapping; however, precise functional mapping is still difficult in patients with language deficits. High gamma activity (HGA) between 80 and 140 Hz on electrocorticography is assumed to reflect localized cortical processing, whereas the cortico-cortical evoked potential (CCEP) can reflect bidirectional responses evoked by monophasic pulse stimuli to the language cortices when there is no patient cooperation. The authors propose the use of "passive" mapping by combining HGA mapping and CCEP recording without active tasks during conscious resections of brain tumors. METHODS Five patients, each with an intraaxial tumor in their dominant hemisphere, underwent conscious resection of their lesion with passive mapping. The authors performed functional localization for the receptive language area, using real-time HGA mapping, by listening passively to linguistic sounds. Furthermore, single electrical pulses were delivered to the identified receptive temporal language area to detect CCEPs in the frontal lobe. All mapping results were validated by ECS, and the sensitivity and specificity were evaluated. RESULTS Linguistic HGA mapping quickly identified the language area in the temporal lobe. Electrical stimulation by linguistic HGA mapping to the identified temporal receptive language area evoked CCEPs on the frontal lobe. The combination of linguistic HGA and frontal CCEPs needed no patient cooperation or effort. In this small case series, the sensitivity and specificity were 93.8% and 89%, respectively. CONCLUSIONS The described technique allows for simple and quick functional brain mapping with higher sensitivity and specificity than ECS mapping. The authors believe that this could improve the reliability of functional brain mapping and facilitate rational and objective operations. Passive mapping also sheds light on the underlying physiological mechanisms of language in the human brain.

The effect of sadness on global-local processing.

PubMed

von Mühlenen, Adrian; Bellaera, Lauren; Singh, Amrendra; Srinivasan, Narayanan

2018-05-04

Gable and Harmon-Jones (Psychological Science, 21(2), 211-215, 2010) reported that sadness broadens attention in a global-local letter task. This finding provided the key test for their motivational intensity account, which states that the level of spatial processing is not determined by emotional valence, but by motivational intensity. However, their finding is at odds with several other studies, showing no effect, or even a narrowing effect of sadness on attention. This paper reports two attempts to replicate the broadening effect of sadness on attention. Both experiments used a global-local letter task, but differed in terms of emotion induction: Experiment 1 used the same pictures as Gable and Harmon-Jones, taken from the IAPS dataset; Experiment 2 used a sad video underlaid with sad music. Results showed a sadness-specific global advantage in the error rates, but not in the reaction times. The same null results were also found in a South-Asian sample in both experiments, showing that effects on global/local processing were not influenced by a culturally related processing bias.

A dual-mode hemispherical sparse array for 3D passive acoustic mapping and skull localization within a clinical MRI guided focused ultrasound device

NASA Astrophysics Data System (ADS)

Crake, Calum; Brinker, Spencer T.; Coviello, Christian M.; Livingstone, Margaret S.; McDannold, Nathan J.

2018-03-01

Previous work has demonstrated that passive acoustic imaging may be used alongside MRI for monitoring of focused ultrasound therapy. However, past implementations have generally made use of either linear arrays originally designed for diagnostic imaging or custom narrowband arrays specific to in-house therapeutic transducer designs, neither of which is fully compatible with clinical MR-guided focused ultrasound (MRgFUS) devices. Here we have designed an array which is suitable for use within an FDA-approved MR-guided transcranial focused ultrasound device, within the bore of a 3 Tesla clinical MRI scanner. The array is constructed from 5  ×  0.4 mm piezoceramic disc elements arranged in pseudorandom fashion on a low-profile laser-cut acrylic frame designed to fit between the therapeutic elements of a 230 kHz InSightec ExAblate 4000 transducer. By exploiting thickness and radial resonance modes of the piezo discs the array is capable of both B-mode imaging at 5 MHz for skull localization, as well as passive reception at the second harmonic of the therapy array for detection of cavitation and 3D passive acoustic imaging. In active mode, the array was able to perform B-mode imaging of a human skull, showing the outer skull surface with good qualitative agreement with MR imaging. Extension to 3D showed the array was able to locate the skull within  ±2 mm/2° of reference points derived from MRI, which could potentially allow registration of a patient to the therapy system without the expense of real-time MRI. In passive mode, the array was able to resolve a point source in 3D within a  ±10 mm region about each axis from the focus, detect cavitation (SNR ~ 12 dB) at burst lengths from 10 cycles to continuous wave, and produce 3D acoustic maps in a flow phantom. Finally, the array was used to detect and map cavitation associated with microbubble activity in the brain in nonhuman primates.

"Active" and "Passive" Lava Resurfacing Processes on Io: A Comparative Study of Loki Patera and Prometheus

NASA Technical Reports Server (NTRS)

Davies, A. G.; Matson, D. L.; Leone, G.; Wilson, L.; Keszthelyi, L. P.

2004-01-01

Studies of Galileo Near Infrared Mapping Spectrometer (NIMS) data and ground based data of volcanism at Prometheus and Loki Patera on Io reveal very different mechanisms of lava emplacement at these two volcanoes. Data analyses show that the periodic nature of Loki Patera s volcanism from 1990 to 2001 is strong evidence that Loki s resurfacing over this period resulted from the foundering of a crust on a lava lake. This process is designated passive , as there is no reliance on sub-surface processes: the foundering of the crust is inevitable. Prometheus, on the other hand, displays an episodicity in its activity which we designate active . Like Kilauea, a close analog, Prometheus s effusive volcanism is dominated by pulses of magma through the nearsurface plumbing system. Each system affords views of lava resurfacing processes through modelling.

Systematic Satellite Observations of the Impact of Aerosols from Passive Volcanic Degassing on Local Cloud Properties

NASA Technical Reports Server (NTRS)

Ebmeier, S. K.; Sayer, A. M.; Grainger, R. G.; Mather, T. A.; Carboni, E.

2014-01-01

The impact of volcanic emissions is a significant source of uncertainty in estimations of aerosol indirect radiative forcing, especially with respect to emissions from passive de-gassing and minor explosions. Understanding the impact of volcanic emissions on indirect radiative forcing is important assessing present day atmospheric properties and also to define the pre-industrial baseline to assess anthropogenic perturbations. We present observations of the time-averaged indirect aerosol effect within 200 km downwind of isolated island volcanoes in regions of low present-day aerosol burden using MODIS and AATSR data. Retrievals of aerosol and cloud properties at Kilauea (Hawaii), Yasur (Vanuatu) and Piton de la Fournaise (Reunion) are rotated about the volcanic vent according to wind direction, so that retrievals downwind of the volcano can be averaged to improve signal to noise ratio. The emissions from all three volcanoes, including those from passive degassing, strombolian activity and minor explosions lead to measurably increased aerosol optical depth downwind of the active vent. Average cloud droplet effective radius is lower downwind of the volcano in all cases, with the peak difference in effective radius ranging from 48 microns at the different volcanoes. A comparison of these observations with cloud properties at isolated islands with no significant source of aerosol suggests that these patterns are not purely orographic in origin. This approach sets out a first step for the systematic measurement of the effects of present day low altitude volcanic emissions on cloud properties, and our observations of unpolluted, isolated marine settings may capture processes similar to those in the preindustrial marine atmosphere.

Electrical image of passive mantle upwelling beneath the northern East Pacific Rise.

PubMed

Key, Kerry; Constable, Steven; Liu, Lijun; Pommier, Anne

2013-03-28

Melt generated by mantle upwelling is fundamental to the production of new oceanic crust at mid-ocean ridges, yet the forces controlling this process are debated. Passive-flow models predict symmetric upwelling due to viscous drag from the diverging tectonic plates, but have been challenged by geophysical observations of asymmetric upwelling that suggest anomalous mantle pressure and temperature gradients, and by observations of concentrated upwelling centres consistent with active models where buoyancy forces give rise to focused convective flow. Here we use sea-floor magnetotelluric soundings at the fast-spreading northern East Pacific Rise to image mantle electrical structure to a depth of about 160 kilometres. Our data reveal a symmetric, high-conductivity region at depths of 20-90 kilometres that is consistent with partial melting of passively upwelling mantle. The triangular region of conductive partial melt matches passive-flow predictions, suggesting that melt focusing to the ridge occurs in the porous melting region rather than along the shallower base of the thermal lithosphere. A deeper conductor observed east of the ridge at a depth of more than 100 kilometres is explained by asymmetric upwelling due to viscous coupling across two nearby transform faults. Significant electrical anisotropy occurs only in the shallowest mantle east of the ridge axis, where high vertical conductivity at depths of 10-20 kilometres indicates localized porous conduits. This suggests that a coincident seismic-velocity anomaly is evidence of shallow magma transport channels rather than deeper off-axis upwelling. We interpret the mantle electrical structure as evidence that plate-driven passive upwelling dominates this ridge segment, with dynamic forces being negligible.

LWIR passive perception system for stealthy unmanned ground vehicle night operations

NASA Astrophysics Data System (ADS)

Lee, Daren; Rankin, Arturo; Huertas, Andres; Nash, Jeremy; Ahuja, Gaurav; Matthies, Larry

2016-05-01

Resupplying forward-deployed units in rugged terrain in the presence of hostile forces creates a high threat to manned air and ground vehicles. An autonomous unmanned ground vehicle (UGV) capable of navigating stealthily at night in off-road and on-road terrain could significantly increase the safety and success rate of such resupply missions for warfighters. Passive night-time perception of terrain and obstacle features is a vital requirement for such missions. As part of the ONR 30 Autonomy Team, the Jet Propulsion Laboratory developed a passive, low-cost night-time perception system under the ONR Expeditionary Maneuver Warfare and Combating Terrorism Applied Research program. Using a stereo pair of forward looking LWIR uncooled microbolometer cameras, the perception system generates disparity maps using a local window-based stereo correlator to achieve real-time performance while maintaining low power consumption. To overcome the lower signal-to-noise ratio and spatial resolution of LWIR thermal imaging technologies, a series of pre-filters were applied to the input images to increase the image contrast and stereo correlator enhancements were applied to increase the disparity density. To overcome false positives generated by mixed pixels, noisy disparities from repeated textures, and uncertainty in far range measurements, a series of consistency, multi-resolution, and temporal based post-filters were employed to improve the fidelity of the output range measurements. The stereo processing leverages multi-core processors and runs under the Robot Operating System (ROS). The night-time passive perception system was tested and evaluated on fully autonomous testbed ground vehicles at SPAWAR Systems Center Pacific (SSC Pacific) and Marine Corps Base Camp Pendleton, California. This paper describes the challenges, techniques, and experimental results of developing a passive, low-cost perception system for night-time autonomous navigation.

Passive signal processing for a miniature Fabry-Perot interferometric sensor with a multimode laser-diode source

NASA Astrophysics Data System (ADS)

Ezbiri, A.; Tatam, R. P.

1995-09-01

A passive signal-processing technique for addressing a miniature low-finesse fiber Fabry-Perot interferometric sensor with a multimode laser diode is reported. Two modes of a multimode laser diode separated by 3 nm are used to obtain quadrature outputs from an \\similar 20 - mu m cavity. Wavelength-division demultiplexing combined with digital signal processing is used to recover the measurand-induced phase change. The technique is demonstrated for the measurement of vibration. The signal-to-noise ratio is \\similar 70 dB at 500 Hz for \\similar pi /2 rad displacement of the mirror, which results in a minimum detectable signal of \\similar 200 mu rad H z-1/2 . A quantitative discussion of miscalibration and systematic errors is presented.

Interlanguage Passive Construction

ERIC Educational Resources Information Center

Simargool, Nirada

2008-01-01

Because the appearance of the passive construction varies cross linguistically, differences exist in the interlanguage (IL) passives attempted by learners of English. One such difference is the widely studied IL pseudo passive, as in "*new cars must keep inside" produced by Chinese speakers. The belief that this is a reflection of L1 language…

Submerged passively-safe power plant

DOEpatents

Herring, J. Stephen

1993-01-01

The invention as presented consists of a submerged passively-safe power station including a pressurized water reactor capable of generating at least 600 MW of electricity, encased in a double hull vessel, and provides fresh water by using the spent thermal energy in a multistage flash desalination process.

Passivated aluminum nanohole arrays for label-free biosensing applications.

PubMed

Canalejas-Tejero, Víctor; Herranz, Sonia; Bellingham, Alyssa; Moreno-Bondi, María Cruz; Barrios, Carlos Angulo

2014-01-22

We report the fabrication and performance of a surface plasmon resonance aluminum nanohole array refractometric biosensor. An aluminum surface passivation treatment based on oxygen plasma is developed in order to circumvent the undesired effects of oxidation and corrosion usually found in aluminum-based biosensors. Immersion tests in deionized water and device simulations are used to evaluate the effectiveness of the passivation process. A label-free bioassay based on biotin analysis through biotin-functionalized dextran-lipase conjugates immobilized on the biosensor-passivated surface in aqueous media is performed as a proof of concept to demonstrate the suitability of these nanostructured aluminum films for biosensing.

Submerged passively-safe power plant

DOEpatents

Herring, J.S.

1993-09-21

The invention as presented consists of a submerged passively-safe power station including a pressurized water reactor capable of generating at least 600 MW of electricity, encased in a double hull vessel, and provides fresh water by using the spent thermal energy in a multistage flash desalination process. 8 figures.

Teflon/SiO2 Bilayer Passivation for Improving the Electrical Reliability of Oxide TFTs Fabricated Using a New Two-Photomask Self-Alignment Process

PubMed Central

Fan, Ching-Lin; Shang, Ming-Chi; Li, Bo-Jyun; Lin, Yu-Zuo; Wang, Shea-Jue; Lee, Win-Der; Hung, Bohr-Ran

2015-01-01

This study proposes a two-photomask process for fabricating amorphous indium–gallium–zinc oxide (a-IGZO) thin-film transistors (TFTs) that exhibit a self-aligned structure. The fabricated TFTs, which lack etching-stop (ES) layers, have undamaged a-IGZO active layers that facilitate superior performance. In addition, we demonstrate a bilayer passivation method that uses a polytetrafluoroethylene (Teflon) and SiO2 combination layer for improving the electrical reliability of the fabricated TFTs. Teflon was deposited as a buffer layer through thermal evaporation. The Teflon layer exhibited favorable compatibility with the underlying IGZO channel layer and effectively protected the a-IGZO TFTs from plasma damage during SiO2 deposition, resulting in a negligible initial performance drop in the a-IGZO TFTs. Compared with passivation-free a-IGZO TFTs, passivated TFTs exhibited superior stability even after 168 h of aging under ambient air at 95% relative humidity. PMID:28788026

Low-temperature fabrication of an HfO2 passivation layer for amorphous indium-gallium-zinc oxide thin film transistors using a solution process.

PubMed

Hong, Seonghwan; Park, Sung Pyo; Kim, Yeong-Gyu; Kang, Byung Ha; Na, Jae Won; Kim, Hyun Jae

2017-11-24

We report low-temperature solution processing of hafnium oxide (HfO 2 ) passivation layers for amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). At 150 °C, the hafnium chloride (HfCl 4 ) precursor readily hydrolyzed in deionized (DI) water and transformed into an HfO 2 film. The fabricated HfO 2 passivation layer prevented any interaction between the back surface of an a-IGZO TFT and ambient gas. Moreover, diffused Hf 4+ in the back-channel layer of the a-IGZO TFT reduced the oxygen vacancy, which is the origin of the electrical instability in a-IGZO TFTs. Consequently, the a-IGZO TFT with the HfO 2 passivation layer exhibited improved stability, showing a decrease in the threshold voltage shift from 4.83 to 1.68 V under a positive bias stress test conducted over 10,000 s.

New opportunities for quality enhancing of images captured by passive THz camera

NASA Astrophysics Data System (ADS)

Trofimov, Vyacheslav A.; Trofimov, Vladislav V.

2014-10-01

As it is well-known, the passive THz camera allows seeing concealed object without contact with a person and this camera is non-dangerous for a person. Obviously, efficiency of using the passive THz camera depends on its temperature resolution. This characteristic specifies possibilities of the detection for concealed object: minimal size of the object; maximal distance of the detection; image quality. Computer processing of the THz image may lead to many times improving of the image quality without any additional engineering efforts. Therefore, developing of modern computer code for its application to THz images is urgent problem. Using appropriate new methods one may expect such temperature resolution which will allow to see banknote in pocket of a person without any real contact. Modern algorithms for computer processing of THz images allow also to see object inside the human body using a temperature trace on the human skin. This circumstance enhances essentially opportunity of passive THz camera applications for counterterrorism problems. We demonstrate opportunities, achieved at present time, for the detection both of concealed objects and of clothes components due to using of computer processing of images captured by passive THz cameras, manufactured by various companies. Another important result discussed in the paper consists in observation of both THz radiation emitted by incandescent lamp and image reflected from ceramic floorplate. We consider images produced by THz passive cameras manufactured by Microsemi Corp., and ThruVision Corp., and Capital Normal University (Beijing, China). All algorithms for computer processing of the THz images under consideration in this paper were developed by Russian part of author list. Keywords: THz wave, passive imaging camera, computer processing, security screening, concealed and forbidden objects, reflected image, hand seeing, banknote seeing, ceramic floorplate, incandescent lamp.

Passive drainage and biofiltration of landfill gas: Australian field trial

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

Dever, S.A.; Swarbrick, G.E.; Stuetz, R.M.

2007-07-01

In Australia a significant number of landfill waste disposal sites do not incorporate measures for the collection and treatment of landfill gas. This includes many old/former landfill sites, rural landfill sites, non-putrescible solid waste and inert waste landfill sites, where landfill gas generation is low and it is not commercially viable to extract and beneficially utilize the landfill gas. Previous research has demonstrated that biofiltration has the potential to degrade methane in landfill gas, however, the microbial processes can be affected by many local conditions and factors including moisture content, temperature, nutrient supply, including the availability of oxygen and methane,more » and the movement of gas (oxygen and methane) to/from the micro-organisms. A field scale trial is being undertaken at a landfill site in Sydney, Australia, to investigate passive drainage and biofiltration of landfill gas as a means of managing landfill gas emissions at low to moderate gas generation landfill sites. The design and construction of the trial is described and the experimental results will provide in-depth knowledge on the application of passive gas drainage and landfill gas biofiltration under Sydney (Australian) conditions, including the performance of recycled materials for the management of landfill gas emissions.« less

Front surface passivation of silicon solar cells with antireflection coating

NASA Technical Reports Server (NTRS)

Crotty, G.; Daud, T.; Kachare, R.

1987-01-01

It is demonstrated that the deposition and postdeposition sintering of an antireflection (AR) coating in hydrogen acts to passivate silicon solar cells. Cells with and without an SiO2 passivating layer, coated with a TiO(x)/Al2O3 AR coating, showed comparable enhancements in short-wavelength spectral response and in open-circuit voltage Voc after sintering at 400 C for 5 min in a hydrogen ambient. The improvement in Voc of cells without SiO2 is attributed to front-surface passivation by the AR coating during processing.

Expanded opportunities of THz passive camera for the detection of concealed objects

NASA Astrophysics Data System (ADS)

Trofimov, Vyacheslav A.; Trofimov, Vladislav V.; Kuchik, Igor E.

2013-10-01

Among the security problems, the detection of object implanted into either the human body or animal body is the urgent problem. At the present time the main tool for the detection of such object is X-raying only. However, X-ray is the ionized radiation and therefore can not be used often. Other way for the problem solving is passive THz imaging using. In our opinion, using of the passive THz camera may help to detect the object implanted into the human body under certain conditions. The physical reason of such possibility arises from temperature trace on the human skin as a result of the difference in temperature between object and parts of human body. Modern passive THz cameras have not enough resolution in temperature to see this difference. That is why, we use computer processing to enhance the passive THz camera resolution for this application. After computer processing of images captured by passive THz camera TS4, developed by ThruVision Systems Ltd., we may see the pronounced temperature trace on the human body skin from the water, which is drunk by person, or other food eaten by person. Nevertheless, there are many difficulties on the way of full soution of this problem. We illustrate also an improvement of quality of the image captured by comercially available passive THz cameras using computer processing. In some cases, one can fully supress a noise on the image without loss of its quality. Using computer processing of the THz image of objects concealed on the human body, one may improve it many times. Consequently, the instrumental resolution of such device may be increased without any additional engineering efforts.

Preliminary results of the Source China Sea passive source OBS array experiment

NASA Astrophysics Data System (ADS)

Yang, T.; Liu, C.; Pei, Y.; Xia, S.

2013-12-01

The Scarborough, or Huangyan, Seamount chain in South China Sea (SCS) represents an extreme case of the global mid-ocean ridge system where the magmatism continues for many million years after the cessation of spreading. To understand this unique process, the South China Sea Deep (SCSD) program funded an experiment deploying a passive source OBS array to image the lithospheric structure beneath the extinct ridge. In April 2012, 18 passive source OBSs, including 15 Guralp CMG-40T OBS and 3 I-4C OBS, were deployed around the Huangyan Island for one year. 11 OBSs were successfully recovered this April, and their data are being processed. Here we present some preliminary results from analyses of this dataset, including the general quality of three-component seismograms, characteristics of seafloor ambient noise spectra, determining the OBS orientation from the Rayleigh wave polarization, and the dispersion analysis of Rayleigh waves. We found that, for most stations, seismograms from teleseismic, regional and local events are generally good with the horizontal records being comparable with vertical component. The noise levels in these seafloor stations are much higher than land-based stations, especially in shorter periods, likely suggesting the direct and stronger impact from the tempestuous SCS. Applications of more sophisticated seismic techniques such as surface wave tomography, seismic anisotropy, receiver function and ambient noise cross-correlation are underway. In addition to the low recovery rate, there are other lessons learned from this experiment. For example, at least two stations have detectable timing problems; Airgun shots should have been used to constrain the timings and orientations in both deployment and recovery. It is still challenging and costly to carry out long-term passive source seismic observations in deep sea.

Fully Passive Wireless Acquisition of Neuropotentials

NASA Astrophysics Data System (ADS)

Schwerdt, Helen N.

The ability to monitor electrophysiological signals from the sentient brain is requisite to decipher its enormously complex workings and initiate remedial solutions for the vast amount of neurologically-based disorders. Despite immense advancements in creating a variety of instruments to record signals from the brain, the translation of such neurorecording instrumentation to real clinical domains places heavy demands on their safety and reliability, both of which are not entirely portrayed by presently existing implantable recording solutions. In an attempt to lower these barriers, alternative wireless radar backscattering techniques are proposed to render the technical burdens of the implant chip to entirely passive neurorecording processes that transpire in the absence of formal integrated power sources or powering schemes along with any active circuitry. These radar-like wireless backscattering mechanisms are used to conceive of fully passive neurorecording operations of an implantable microsystem. The fully passive device potentially manifests inherent advantages over current wireless implantable and wired recording systems: negligible heat dissipation to reduce risks of brain tissue damage and minimal circuitry for long term reliability as a chronic implant. Fully passive neurorecording operations are realized via intrinsic nonlinear mixing properties of the varactor diode. These mixing and recording operations are directly activated by wirelessly interrogating the fully passive device with a microwave carrier signal. This fundamental carrier signal, acquired by the implant antenna, mixes through the varactor diode along with the internal targeted neuropotential brain signals to produce higher frequency harmonics containing the targeted neuropotential signals. These harmonics are backscattered wirelessly to the external interrogator that retrieves and recovers the original neuropotential brain signal. The passive approach removes the need for internal power

Novel Approach to Front Contact Passivation for CdTe Photovoltaics

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

Kephart, Jason M.

2018-02-18

The goal of this project was to study the use of sputter-deposited oxide materials for interface passivation of CdTe-based photovoltaics. Several candidate materials were chosen based on their promise in passivating the CdTe and CdSeTe semiconductor interface, chemical and thermal stability to device processing, and ability to be deposited by sputter deposition.

Novel Passivating/Antireflective Coatings for Space Solar Cells

NASA Technical Reports Server (NTRS)

Faur, Mircea; Faur, Maria; Bailey, S. G.; Flood, D. J.; Faur, H. M.; Mateescu, C. G.; Alterovitz, S. A.; Scheiman, D.; Jenkins, P. P.; Brinker, D. J.

2005-01-01

We are developing a novel process to grow passivating/antireflective (AR) coatings for terrestrial and space solar cells. Our approach involves a Room Temperature Wet Chemical Growth (RTWCG) process, which was pioneered, and is under development at SPECMAT, Inc., under a Reimbursable Space Act Agreement with NASA Glenn Research Center. The RTWCG passivating/AR coatings with graded index of refraction are applied in one easy step on finished (bare) cells. The RTWCG coatings grown on planar, textured and porous Si, as well as on poly-Si, CuInSe2, and III-V substrates, show excellent uniformity irrespective of surface topography, crystal orientation, size and shape. In this paper we present some preliminary results of the RTWCG coatings on Si and III-V substrates that show very good potential for use as a passivation/AR coating for space solar cell applications. Compared to coatings grown using conventional techniques, the RTWCG coatings have the potential to reduce reflection losses and improve current collection near the illuminated surface of space solar cells, while reducing the fabrication costs.

Symbol processing in the left angular gyrus: evidence from passive perception of digits.

PubMed

Price, Gavin R; Ansari, Daniel

2011-08-01

Arabic digits are one of the most ubiquitous symbol sets in the world. While there have been many investigations into the neural processing of the semantic information digits represent (e.g. through numerical comparison tasks), little is known about the neural mechanisms which support the processing of digits as visual symbols. To characterise the component neurocognitive mechanisms which underlie numerical cognition, it is essential to understand the processing of digits as a visual category, independent of numerical magnitude processing. The 'Triple Code Model' (Dehaene, 1992; Dehaene and Cohen, 1995) posits an asemantic visual code for processing Arabic digits in the ventral visual stream, yet there is currently little empirical evidence in support of this code. This outstanding question was addressed in the current functional Magnetic Resonance (fMRI) study by contrasting brain responses during the passive viewing of digits versus letters and novel symbols at short (50 ms) and long (500 ms) presentation times. The results of this study reveal increased activation for familiar symbols (digits and letters) relative to unfamiliar symbols (scrambled digits and letters) at long presentation durations in the left dorsal Angular gyrus (dAG). Furthermore, increased activation for Arabic digits was observed in the left ventral Angular gyrus (vAG) in comparison to letters, scrambled digits and scrambled letters at long presentation durations, but no digit specific activation in any region at short presentation durations. These results suggest an absence of a digit specific 'Visual Number Form Area' (VNFA) in the ventral visual cortex, and provide evidence for the role of the left ventral AG during the processing of digits in the absence of any explicit processing demands. We conclude that Arabic digit processing depends specifically on the left AG rather than a ventral visual stream VNFA. Copyright © 2011 Elsevier Inc. All rights reserved.

Folding in and out: passive morphing in flapping wings.

PubMed

Stowers, Amanda K; Lentink, David

2015-03-25

We present a new mechanism for passive wing morphing of flapping wings inspired by bat and bird wing morphology. The mechanism consists of an unactuated hand wing connected to the arm wing with a wrist joint. Flapping motion generates centrifugal accelerations in the hand wing, forcing it to unfold passively. Using a robotic model in hover, we made kinematic measurements of unfolding kinematics as functions of the non-dimensional wingspan fold ratio (2-2.5) and flapping frequency (5-17 Hz) using stereo high-speed cameras. We find that the wings unfold passively within one to two flaps and remain unfolded with only small amplitude oscillations. To better understand the passive dynamics, we constructed a computer model of the unfolding process based on rigid body dynamics, contact models, and aerodynamic correlations. This model predicts the measured passive unfolding within about one flap and shows that unfolding is driven by centrifugal acceleration induced by flapping. The simulations also predict that relative unfolding time only weakly depends on flapping frequency and can be reduced to less than half a wingbeat by increasing flapping amplitude. Subsequent dimensional analysis shows that the time required to unfold passively is of the same order of magnitude as the flapping period. This suggests that centrifugal acceleration can drive passive unfolding within approximately one wingbeat in small and large wings. Finally, we show experimentally that passive unfolding wings can withstand impact with a branch, by first folding and then unfolding passively. This mechanism enables flapping robots to squeeze through clutter without sophisticated control. Passive unfolding also provides a new avenue in morphing wing design that makes future flapping morphing wings possibly more energy efficient and light-weight. Simultaneously these results point to possible inertia driven, and therefore metabolically efficient, control strategies in bats and birds to morph or recover

A photometrically and spectroscopically confirmed population of passive spiral galaxies

NASA Astrophysics Data System (ADS)

Fraser-McKelvie, Amelia; Brown, Michael J. I.; Pimbblet, Kevin A.; Dolley, Tim; Crossett, Jacob P.; Bonne, Nicolas J.

2016-10-01

We have identified a population of passive spiral galaxies from photometry and integral field spectroscopy. We selected z < 0.035 spiral galaxies that have WISE colours consistent with little mid-infrared emission from warm dust. Matched aperture photometry of 51 spiral galaxies in ultraviolet, optical and mid-infrared show these galaxies have colours consistent with passive galaxies. Six galaxies form a spectroscopic pilot study and were observed using the Wide-Field Spectrograph to check for signs of nebular emission from star formation. We see no evidence of substantial nebular emission found in previous red spiral samples. These six galaxies possess absorption-line spectra with 4000 Å breaks consistent with an average luminosity-weighted age of 2.3 Gyr. Our photometric and integral field spectroscopic observations confirm the existence of a population of local passive spiral galaxies, implying that transformation into early-type morphologies is not required for the quenching of star formation.

Global and local processing near the left and right hands

PubMed Central

Langerak, Robin M.; La Mantia, Carina L.; Brown, Liana E.

2013-01-01

Visual targets can be processed more quickly and reliably when a hand is placed near the target. Both unimodal and bimodal representations of hands are largely lateralized to the contralateral hemisphere, and since each hemisphere demonstrates specialized cognitive processing, it is possible that targets appearing near the left hand may be processed differently than targets appearing near the right hand. The purpose of this study was to determine whether visual processing near the left and right hands interacts with hemispheric specialization. We presented hierarchical-letter stimuli (e.g., small characters used as local elements to compose large characters at the global level) near the left or right hands separately and instructed participants to discriminate the presence of target letters (X and O) from non-target letters (T and U) at either the global or local levels as quickly as possible. Targets appeared at either the global or local level of the display, at both levels, or were absent from the display; participants made foot-press responses. When discriminating target presence at the global level, participants responded more quickly to stimuli presented near the left hand than near either the right hand or in the no-hand condition. Hand presence did not influence target discrimination at the local level. Our interpretation is that left-hand presence may help participants discriminate global information, a right hemisphere (RH) process, and that the left hand may influence visual processing in a way that is distinct from the right hand. PMID:24194725

Monitoring and localization of buried plastic natural gas pipes using passive RF tags

NASA Astrophysics Data System (ADS)

Mondal, Saikat; Kumar, Deepak; Ghazali, Mohd. Ifwat; Chahal, Prem; Udpa, Lalita; Deng, Yiming

2018-04-01

A passive harmonic radio frequency (RF) tag on the pipe with added sensing capabilities is proposed in this paper. Radio frequency identification (RFID) based tagging has already emerged as a potential solution for chemical sensing, location detection, animal tagging, etc. Harmonic transponders are already quite popular compared to conventional RFIDs due to their improved signal to noise ratio (SNR). However, the operating frequency, transmitted power and tag efficiency become critical issues for underground RFIDs. In this paper, a comprehensive on-tag sensing, power budget and frequency analyses is performed for buried harmonic tag design. Accurate tracking of infrastructure burial depth is proposed to reduce the probability of failure of underground pipelines. Burial depth is estimated using phase information of received signals at different frequencies calculated using genetic algorithm (GA) based optimization for post processing. Suitable frequency range is determined for a variety of soil with different moisture content for small tag-antenna size. Different types of harmonic tags such as 1) Schottky diode, 2) Non-linear Transmission Line (NLTL) were compared for underground applications. In this study, the power, frequency and tag design have been optimized to achieve small antenna size, minimum signal loss and simple reader circuit for underground detection at up to 5 feet depth in different soil medium and moisture contents.

Method of passivating semiconductor surfaces

DOEpatents

Wanlass, Mark W.

1990-01-01

A method of passivating Group III-V or II-VI semiconductor compound surfaces. The method includes selecting a passivating material having a lattice constant substantially mismatched to the lattice constant of the semiconductor compound. The passivating material is then grown as an ultrathin layer of passivating material on the surface of the Group III-V or II-VI semiconductor compound. The passivating material is grown to a thickness sufficient to maintain a coherent interface between the ultrathin passivating material and the semiconductor compound. In addition, a device formed from such method is also disclosed.

Field intercomparison of ammonia passive samplers: results and lessons learned.

NASA Astrophysics Data System (ADS)

Stephens, Amy; Leeson, Sarah; Jones, Matthew; van Dijk, Netty; Kentisbeer, John; Twigg, Marsailidh; Simmons, Ivan; Braban, Christine; Martin, Nick; Poskitt, Janet; Ferm, Martin; Seitler, Eva; Sacco, Paolo; Gates, Linda; Stolk, Ariën; Stoll, Jean-Marc; Tang, Sim

2017-04-01

Ammonia pollution contributes significantly to eutrophication and acidification of ecosystems with resultant losses of biodiversity and ecosystem changes. Monitoring of ambient ammonia over a wide spatial and long temporal scales is primarily done with low-cost diffusive samplers. Less frequently, surface flux measurements of ammonia can be made using passive samplers at plot scale. This paper will present a field intercomparison conducted within the MetNH3 project to assess the performance of passive samplers for ambient measurements of ammonia. Eight different designs of commercial passive samplers housed in shelters provided by the manufacturer/laboratory were exposed over an 8-week period at the Whim experimental field site in Scotland between August and October 2016. Whim Bog has a facility in place for controlled releases of ammonia (http://www.whimbog.ceh.ac.uk/). Automated conditional release from the line source occurs when the wind direction in the preceding minute is from the northeast (wind sector 180-215°) and wind speed is > 5 m s-1. The passive samplers were exposed at different distances from the release source (16, 32 and 60 m) and also at a background location. Most were exposed for 2 x 4-week long periods and some for 4 x 2-week long periods. At the 32 m position, an active denuder method, the CEH DELTA sampler and a continuous high temporal resolution wet chemistry ammonia instrument (AiRRmonia, Mechatronics, NL.) were also deployed alongside the passive samplers to provide reference measurements of ammonia. Results are presented within the context of the MetNH3 CATFAC controlled laboratory exposure assessments. The results are discussed in terms of typical deployments of passive samplers and quality control. Measurement for policy evidence for both local and regional studies using passive samplers are discussed.

Priming global and local processing of composite faces: revisiting the processing-bias effect on face perception.

PubMed

Gao, Zaifeng; Flevaris, Anastasia V; Robertson, Lynn C; Bentin, Shlomo

2011-07-01

We used the composite-face illusion and Navon stimuli to determine the consequences of priming local or global processing on subsequent face recognition. The composite-face illusion reflects the difficulty of ignoring the task-irrelevant half-face while attending the task-relevant half if the half-faces in the composite are aligned. On each trial, participants first matched two Navon stimuli, attending to either the global or the local level, and then matched the upper halves of two composite faces presented sequentially. Global processing of Navon stimuli increased the sensitivity to incongruence between the upper and the lower halves of the composite face, relative to a baseline in which the composite faces were not primed. Local processing of Navon stimuli did not influence the sensitivity to incongruence. Although incongruence induced a bias toward different responses, this bias was not modulated by priming. We conclude that global processing of Navon stimuli augments holistic processing of the face.

Changing attitudes to infection management in primary care: a controlled trial of active versus passive guideline implementation strategies.

PubMed

Onion, C W; Bartzokas, C A

1998-04-01

When attempting to implement evidence-based medicine, such as through clinical guidelines, we often rely on passive educational tactics, for example didactic lectures and bulletins. These methods involve the recipient in relatively superficial processing of information, and any consequent attitude changes can be expected to be short-lived. However, active methods, such as practice-based discussion, should involve recipients in deep processing, with more enduring attitude changes. In this experiment, the aim was to assess the efficacy of an active strategy at promoting deep processing and its effectiveness, relative to a typical passive method, at changing attitudes between groups of GPs over 12 months across an English Health District. All 191 GPs operating from 69 practices in the Wirral Health District of Northwest England were assigned, with minimization of known confounding variables, to three experimental groups: active, passive and control. The groups were shown to have similar learning styles. The objective of the study was to impart knowledge of best management of infections as captured in a series of locally developed clinical guidelines. The passive group GPs were given a copy of the guidelines and were invited to an hour-long lecture event. The GPs in the deep group were given a copy of the guidelines and were invited to engage in an hour-long discussion about the guideline content at their own premises. The control group received neither the guidelines nor any educational contact regarding them. Three months before and 12 months after the interventions, all GPs were sent a postal questionnaire on their preferred empirical antibiotic for 10 common bacterial infections. The responses were compared in order to ascertain whether increased knowledge of best clinical practice was evident in each group. Seventy-five per cent (144/191) of GPs responded to the pre-intervention questionnaire, 62 % (119/191) post-intervention. Thirty-four per cent (22/64) of GPs

Management of local economic and ecological system of coal processing company

NASA Astrophysics Data System (ADS)

Kiseleva, T. V.; Mikhailov, V. G.; Karasev, V. A.

2016-10-01

The management issues of local ecological and economic system of coal processing company - coal processing plant - are considered in the article. The objectives of the research are the identification and the analysis of local ecological and economic system (coal processing company) performance and the proposals for improving the mechanism to support the management decision aimed at improving its environmental safety. The data on the structure of run-of-mine coal processing products are shown. The analysis of main ecological and economic indicators of coal processing enterprises, characterizing the state of its environmental safety, is done. The main result of the study is the development of proposals to improve the efficiency of local enterprise ecological and economic system management, including technical, technological and business measures. The results of the study can be recommended to industrial enterprises to improve their ecological and economic efficiency.

Investigation of passive films on nickel Alloy 690 in lead-containing environments

NASA Astrophysics Data System (ADS)

Peng, B.; Lu, B. T.; Luo, J. L.; Lu, Y. C.; Ma, H. Y.

2008-09-01

Passive films formed on Alloy UNS N06690 were investigated in simulated crevice chemistries. It was found the role of lead in corrosion processes is strongly dependent on the pH value of the testing solutions. At pH 1.5 the effect of lead is narrowly noticeable; while at pH 12.7, lead has a significant influence on the electrochemical performance of alloy UNS N06690. The lead alters the surface morphologies at both pH and account for higher hydroxide content in the surface film at pH 12.7. The lead incorporation hinders the formation of spinel oxides during the passivation in alkaline solution. Nanoindentation tests indicate a significant lead-induced degradation in the mechanical properties of passive films. The passivation degradation is attributed to detrimental effects of lead via interrupting the dehydration process and hindering the formation of protective layers on the alloy surface.

Effects of global and local contexts on chord processing: An ERP study.

PubMed

Zhang, Jingjing; Zhou, Xuefeng; Chang, Ruohan; Yang, Yufang

2018-01-31

In real life, the processing of an incoming event is continuously influenced by prior information at multiple timescales. The present study investigated how harmonic contexts at both local and global levels influence the processing of an incoming chord in an event-related potentials experiment. Chord sequences containing two phrases were presented to musically trained listeners, with the last critical chord either harmonically related or less related to its preceding context at local and/or global levels. ERPs data showed an ERAN-like effect for local context in early time window and a N5-like component for later interaction between the local context and global context. These results suggest that both the local and global contexts influence the processing of an incoming music event, and the local effect happens earlier than the global. Moreover, the interaction between the local context and global context in N5 may suggest that music syntactic integration at local level takes place prior to the integration at global level. Copyright © 2017 Elsevier Ltd. All rights reserved.

Method of passivating semiconductor surfaces

DOEpatents

Wanlass, M.W.

1990-06-19

A method is described for passivating Group III-V or II-VI semiconductor compound surfaces. The method includes selecting a passivating material having a lattice constant substantially mismatched to the lattice constant of the semiconductor compound. The passivating material is then grown as an ultrathin layer of passivating material on the surface of the Group III-V or II-VI semiconductor compound. The passivating material is grown to a thickness sufficient to maintain a coherent interface between the ultrathin passivating material and the semiconductor compound. In addition, a device formed from such method is also disclosed.

Alternative to Nitric Acid Passivation Project Overview

NASA Technical Reports Server (NTRS)

Lewis, Pattie L.

2013-01-01

The standard practice for protection of stainless steel is a process called passivation. This procedure results in the formation of a metal oxide layer to prevent corrosion. Typical passivation procedures call for the use of nitric acid which exhibits excellent corrosion performance; however, there are a number of environmental, worker safety, and operational issues associated with its use. The longtime military specification for the passivation of stainless steel was cancelled in favor of newer specifications which allow for the use of citric acid in place of nitric acid. Citric acid offers a variety of benefits that include increased safety for personnel, reduced environmental impact, and reduced operational costs. There have been few studies, however, to determine whether citric acid is an acceptable alternative for NASA and DoD. This paper details activities to date including development of the joint test plan, on-going and planned testing, and preliminary results.

Passive Education

ERIC Educational Resources Information Center

Bojesen, Emile

2018-01-01

This paper does not present an advocacy of a passive education as opposed to an active education nor does it propose that passive education is in any way 'better' or more important than active education. Through readings of Maurice Blanchot, Jacques Derrida and B.S. Johnson, and gentle critiques of Jacques Rancière and John Dewey, passive…

Signal processing for passive detection and classification of underwater acoustic signals

NASA Astrophysics Data System (ADS)

Chung, Kil Woo

2011-12-01

This dissertation examines signal processing for passive detection, classification and tracking of underwater acoustic signals for improving port security and the security of coastal and offshore operations. First, we consider the problem of passive acoustic detection of a diver in a shallow water environment. A frequency-domain multi-band matched-filter approach to swimmer detection is presented. The idea is to break the frequency contents of the hydrophone signals into multiple narrow frequency bands, followed by time averaged (about half of a second) energy calculation over each band. Then, spectra composed of such energy samples over the chosen frequency bands are correlated to form a decision variable. The frequency bands with highest Signal/Noise ratio are used for detection. The performance of the proposed approach is demonstrated for experimental data collected for a diver in the Hudson River. We also propose a new referenceless frequency-domain multi-band detector which, unlike other reference-based detectors, does not require a diver specific signature. Instead, our detector matches to a general feature of the diver spectrum in the high frequency range: the spectrum is roughly periodic in time and approximately flat when the diver exhales. The performance of the proposed approach is demonstrated by using experimental data collected from the Hudson River. Moreover, we present detection, classification and tracking of small vessel signals. Hydroacoustic sensors can be applied for the detection of noise generated by vessels, and this noise can be used for vessel detection, classification and tracking. This dissertation presents recent improvements aimed at the measurement and separation of ship DEMON (Detection of Envelope Modulation on Noise) acoustic signatures in busy harbor conditions. Ship signature measurements were conducted in the Hudson River and NY Harbor. The DEMON spectra demonstrated much better temporal stability compared with the full ship

Internal passivation of Al-based microchannel devices by electrochemical anodization

NASA Astrophysics Data System (ADS)

Hymel, Paul J.; Guan, D. S.; Mu, Yang; Meng, W. J.; Meng, Andrew C.

2015-02-01

Metal-based microchannel devices have wide-ranging applications. We report here a method to electrochemically anodize the internal surfaces of Al microchannels, with the purpose of forming a uniform and dense anodic aluminum oxide (AAO) layer on microchannel internal surfaces for chemical passivation and corrosion resistance. A pulsed electrolyte flow was utilized to emulate conventional anodization processes while replenishing depleted ionic species within Al microtubes and microchannels. After anodization, the AAO film was sealed in hot water to close the nanopores. Focused ion beam (FIB) sectioning, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) were utilized to characterize the AAO morphology and composition. Potentiodynamic polarization corrosion testing of anodized Al microtube half-sections in a NaCl solution showed an order of magnitude decrease in anodic corrosion current when compared to an unanodized tube. The surface passivation process was repeated for Al-based microchannel heat exchangers. A corrosion testing method based on the anodization process showed higher resistance to ion transport through the anodized specimens than unanodized specimens, thus verifying the internal anodization and sealing process as a viable method for surface passivation of Al microchannel devices.

Perception of shapes targeting local and global processes in autism spectrum disorders.

PubMed

Grinter, Emma J; Maybery, Murray T; Pellicano, Elizabeth; Badcock, Johanna C; Badcock, David R

2010-06-01

Several researchers have found evidence for impaired global processing in the dorsal visual stream in individuals with autism spectrum disorders (ASDs). However, support for a similar pattern of visual processing in the ventral visual stream is less consistent. Critical to resolving the inconsistency is the assessment of local and global form processing ability. Within the visual domain, radial frequency (RF) patterns - shapes formed by sinusoidally varying the radius of a circle to add 'bumps' of a certain number to a circle - can be used to examine local and global form perception. Typically developing children and children with an ASD discriminated between circles and RF patterns that are processed either locally (RF24) or globally (RF3). Children with an ASD required greater shape deformation to identify RF3 shapes compared to typically developing children, consistent with difficulty in global processing in the ventral stream. No group difference was observed for RF24 shapes, suggesting intact local ventral-stream processing. These outcomes support the position that a deficit in global visual processing is present in ASDs, consistent with the notion of Weak Central Coherence.

Potential of bias correction for downscaling passive microwave and soil moisture data

USDA-ARS?s Scientific Manuscript database

Passive microwave satellites such as SMOS (Soil Moisture and Ocean Salinity) or SMAP (Soil Moisture Active Passive) observe brightness temperature (TB) and retrieve soil moisture at a spatial resolution greater than most hydrological processes. Bias correction is proposed as a simple method to disag...

Hydrogenation of passivated contacts

DOEpatents

Nemeth, William; Yuan, Hao-Chih; LaSalvia, Vincenzo; Stradins, Pauls; Page, Matthew R.

2018-03-06

Methods of hydrogenation of passivated contacts using materials having hydrogen impurities are provided. An example method includes applying, to a passivated contact, a layer of a material, the material containing hydrogen impurities. The method further includes subsequently annealing the material and subsequently removing the material from the passivated contact.

The rhetoric and realities of integrating air quality into the local transport planning process in English local authorities.

PubMed

Olowoporoku, Dotun; Hayes, Enda; Longhurst, James; Parkhurst, Graham

2012-06-30

Regardless of its intent and purposes, the first decade of the Local Air Quality Management (LAQM) framework had little or no effect in reducing traffic-related air pollution in the UK. Apart from the impact of increased traffic volumes, the major factor attributed to this failure is that of policy disconnect between the process of diagnosing air pollution and its management, thereby limiting the capability of local authorities to control traffic-related sources of air pollution. Integrating air quality management into the Local Transport Plan (LTP) process therefore presents opportunities for enabling political will, funding and joined-up policy approach to reduce this limitation. However, despite the increased access to resources for air quality measures within the LTP process, there are local institutional, political and funding constraints which reduce the impact of these policy interventions on air quality management. This paper illustrate the policy implementation gaps between central government policy intentions and the local government process by providing evidence of the deprioritisation of air quality management compared to the other shared priorities in the LTP process. We draw conclusions on the policy and practice of integrating air quality management into transport planning. The evidence thereby indicate the need for a policy shift from a solely localised hotspot management approach, in which the LAQM framework operates, to a more holistic management of vehicular emissions within wider spatial administrative areas. Copyright © 2012 Elsevier Ltd. All rights reserved.

On data processing required to derive mobility patterns from passively-generated mobile phone data

PubMed Central

Wang, Feilong; Chen, Cynthia

2018-01-01

Passively-generated mobile phone data is emerging as a potential data source for transportation research and applications. Despite the large amount of studies based on the mobile phone data, only a few have reported the properties of such data, and documented how they have processed the data. In this paper, we describe two types of common mobile phone data: Call Details Record (CDR) data and sightings data, and propose a data processing framework and the associated algorithms to address two key issues associated with the sightings data: locational uncertainty and oscillation. We show the effectiveness of our proposed methods in addressing these two issues compared to the state of art algorithms in the field. We also demonstrate that without proper processing applied to the data, the statistical regularity of human mobility patterns—a key, significant trait identified for human mobility—is over-estimated. We hope this study will stimulate more studies in examining the properties of such data and developing methods to address them. Though not as glamorous as those directly deriving insights on mobility patterns (such as statistical regularity), understanding properties of such data and developing methods to address them is a fundamental research topic on which important insights are derived on mobility patterns. PMID:29398790

Attentional selection of relative SF mediates global versus local processing: evidence from EEG.

PubMed

Flevaris, Anastasia V; Bentin, Shlomo; Robertson, Lynn C

2011-06-13

Previous research on functional hemispheric differences in visual processing has associated global perception with low spatial frequency (LSF) processing biases of the right hemisphere (RH) and local perception with high spatial frequency (HSF) processing biases of the left hemisphere (LH). The Double Filtering by Frequency (DFF) theory expanded this hypothesis by proposing that visual attention selects and is directed to relatively LSFs by the RH and relatively HSFs by the LH, suggesting a direct causal relationship between SF selection and global versus local perception. We tested this idea in the current experiment by comparing activity in the EEG recorded at posterior right and posterior left hemisphere sites while participants' attention was directed to global or local levels of processing after selection of relatively LSFs versus HSFs in a previous stimulus. Hemispheric asymmetry in the alpha band (8-12 Hz) during preparation for global versus local processing was modulated by the selected SF. In contrast, preparatory activity associated with selection of SF was not modulated by the previously attended level (global/local). These results support the DFF theory that top-down attentional selection of SF mediates global and local processing.

Multisensory integration in early vestibular processing in mice: the encoding of passive vs. active motion

PubMed Central

Medrea, Ioana

2013-01-01

The mouse has become an important model system for studying the cellular basis of learning and coding of heading by the vestibular system. Here we recorded from single neurons in the vestibular nuclei to understand how vestibular pathways encode self-motion under natural conditions, during which proprioceptive and motor-related signals as well as vestibular inputs provide feedback about an animal's movement through the world. We recorded neuronal responses in alert behaving mice focusing on a group of neurons, termed vestibular-only cells, that are known to control posture and project to higher-order centers. We found that the majority (70%, n = 21/30) of neurons were bimodal, in that they responded robustly to passive stimulation of proprioceptors as well as passive stimulation of the vestibular system. Additionally, the linear summation of a given neuron's vestibular and neck sensitivities predicted well its responses when both stimuli were applied simultaneously. In contrast, neuronal responses were suppressed when the same motion was actively generated, with the one striking exception that the activity of bimodal neurons similarly and robustly encoded head on body position in all conditions. Our results show that proprioceptive and motor-related signals are combined with vestibular information at the first central stage of vestibular processing in mice. We suggest that these results have important implications for understanding the multisensory integration underlying accurate postural control and the neural representation of directional heading in the head direction cell network of mice. PMID:24089394

Testing the Feasibility of a Passive and Active Case Ascertainment System for Multiple Rare Conditions Simultaneously: The Experience in Three US States

PubMed Central

McDermott, Suzanne; Ruttenber, Margaret; Mann, Joshua; Smith, Michael G; Royer, Julie; Valdez, Rodolfo

2016-01-01

Background Owing to their low prevalence, single rare conditions are difficult to monitor through current state passive and active case ascertainment systems. However, such monitoring is important because, as a group, rare conditions have great impact on the health of affected individuals and the well-being of their caregivers. A viable approach could be to conduct passive and active case ascertainment of several rare conditions simultaneously. This is a report about the feasibility of such an approach. Objective To test the feasibility of a case ascertainment system with passive and active components aimed at monitoring 3 rare conditions simultaneously in 3 states of the United States (Colorado, Kansas, and South Carolina). The 3 conditions are spina bifida, muscular dystrophy, and fragile X syndrome. Methods Teams from each state evaluated the possibility of using current or modified versions of their local passive and active case ascertainment systems and datasets to monitor the 3 conditions. Together, these teams established the case definitions and selected the variables and the abstraction tools for the active case ascertainment approach. After testing the ability of their local passive and active case ascertainment system to capture all 3 conditions, the next steps were to report the number of cases detected actively and passively for each condition, to list the local barriers against the combined passive and active case ascertainment system, and to describe the experiences in trying to overcome these barriers. Results During the test period, the team from South Carolina was able to collect data on all 3 conditions simultaneously for all ages. The Colorado team was also able to collect data on all 3 conditions but, because of age restrictions in its passive and active case ascertainment system, it was able to report few cases of fragile X syndrome. The team from Kansas was able to collect data only on spina bifida. For all states, the implementation of an

Advanced information processing system: Local system services

NASA Technical Reports Server (NTRS)

Burkhardt, Laura; Alger, Linda; Whittredge, Roy; Stasiowski, Peter

1989-01-01

The Advanced Information Processing System (AIPS) is a multi-computer architecture composed of hardware and software building blocks that can be configured to meet a broad range of application requirements. The hardware building blocks are fault-tolerant, general-purpose computers, fault-and damage-tolerant networks (both computer and input/output), and interfaces between the networks and the computers. The software building blocks are the major software functions: local system services, input/output, system services, inter-computer system services, and the system manager. The foundation of the local system services is an operating system with the functions required for a traditional real-time multi-tasking computer, such as task scheduling, inter-task communication, memory management, interrupt handling, and time maintenance. Resting on this foundation are the redundancy management functions necessary in a redundant computer and the status reporting functions required for an operator interface. The functional requirements, functional design and detailed specifications for all the local system services are documented.

Embedded Spherical Localization for Micro Underwater Vehicles Based on Attenuation of Electro-Magnetic Carrier Signals

PubMed Central

Duecker, Daniel-André; Geist, A. René; Hengeler, Michael; Kreuzer, Edwin; Pick, Marc-André; Rausch, Viktor; Solowjow, Eugen

2017-01-01

Self-localization is one of the most challenging problems for deploying micro autonomous underwater vehicles (μAUV) in confined underwater environments. This paper extends a recently-developed self-localization method that is based on the attenuation of electro-magnetic waves, to the μAUV domain. We demonstrate a compact, low-cost architecture that is able to perform all signal processing steps present in the original method. The system is passive with one-way signal transmission and scales to possibly large μAUV fleets. It is based on the spherical localization concept. We present results from static and dynamic position estimation experiments and discuss the tradeoffs of the system. PMID:28445419

Embedded Spherical Localization for Micro Underwater Vehicles Based on Attenuation of Electro-Magnetic Carrier Signals.

PubMed

Duecker, Daniel-André; Geist, A René; Hengeler, Michael; Kreuzer, Edwin; Pick, Marc-André; Rausch, Viktor; Solowjow, Eugen

2017-04-26

Self-localization is one of the most challenging problems for deploying micro autonomous underwater vehicles ( μ AUV) in confined underwater environments. This paper extends a recently-developed self-localization method that is based on the attenuation of electro-magnetic waves, to the μ AUV domain. We demonstrate a compact, low-cost architecture that is able to perform all signal processing steps present in the original method. The system is passive with one-way signal transmission and scales to possibly large μ AUV fleets. It is based on the spherical localization concept. We present results from static and dynamic position estimation experiments and discuss the tradeoffs of the system.

Understanding the synthesis, performance, and passivation of metal oxide photocathodes

NASA Astrophysics Data System (ADS)

Flynn, Cory James

Metal oxides are ubiquitous in semiconductor technologies for their ease of synthesis, chemical stability, and tunable optical/electronic properties. These properties are especially important to fabricating efficient photoelectrodes for solar-energy applications. To counter inherent problems in these materials, new strategies were developed and successfully implemented on the widely-utilized p-type semiconductor, NiO. As the size of semiconductor materials shrink, the surface-to-volume ratio increases and surface defects dominate the performance of the materials. Surface defects can alter the optical and electronic characteristics of materials by changing the Fermi level, charge-carrier mobility, and surface reactivity. We first present a strategy to increase the electrical mobility of mesoporous metal oxide electrode materials by optimizing shape morphology. Transitioning from nanospheres to hexagonal nanoplatelets increased the charge-carrier mobility by one order of magnitude. We then employed this improved material with a new vapor-phase deposition method termed targeted atomic deposition (TAD) to selectively passivate defect sites in semiconductor nanomaterials. We demonstrated the capabilities of this passivation method by applying a TAD of aluminum onto NiO. By exploiting a temperature-dependent deposition process, we selectively passivated the highly reactive sites in NiO: oxygen dangling bonds associated with Ni vacancies. The TAD treatment completely passivated all measurable surface defects, optically bleached the material, and significantly improved all photovoltaic performance metrics in dye-sensitized solar cells. The technique was proven to be generic to numerous forms of NiO. While the implementation of TAD of Al was successful, the process involved pulsing two precursors to passivate the material. Ideally, the TAD process should require only a single precursor and continuous exposure. We utilized a continuous flow of diborane to perform a TAD of B

Exciton localization in solution-processed organolead trihalide perovskites

PubMed Central

He, Haiping; Yu, Qianqian; Li, Hui; Li, Jing; Si, Junjie; Jin, Yizheng; Wang, Nana; Wang, Jianpu; He, Jingwen; Wang, Xinke; Zhang, Yan; Ye, Zhizhen

2016-01-01

Organolead trihalide perovskites have attracted great attention due to the stunning advances in both photovoltaic and light-emitting devices. However, the photophysical properties, especially the recombination dynamics of photogenerated carriers, of this class of materials are controversial. Here we report that under an excitation level close to the working regime of solar cells, the recombination of photogenerated carriers in solution-processed methylammonium–lead–halide films is dominated by excitons weakly localized in band tail states. This scenario is evidenced by experiments of spectral-dependent luminescence decay, excitation density-dependent luminescence and frequency-dependent terahertz photoconductivity. The exciton localization effect is found to be general for several solution-processed hybrid perovskite films prepared by different methods. Our results provide insights into the charge transport and recombination mechanism in perovskite films and help to unravel their potential for high-performance optoelectronic devices. PMID:26996605

Passive coherent location system simulation and evaluation

NASA Astrophysics Data System (ADS)

Slezák, Libor; Kvasnička, Michael; Pelant, Martin; Vávra, Jiř; Plšek, Radek

2006-02-01

Passive Coherent Location (PCL) is going to be important and perspective system of passive location of non cooperative and stealth targets. It works with the sources of irradiation of opportunity. PCL is intended to be a part of mobile Air Command and Control System (ACCS) as a Deployable ACCS Component (DAC). The company ERA works on PCL system parameters verification program by complete PCL simulator development since the year 2003. The Czech DoD takes financial participation on this program. The moving targets scenario, the RCS calculation by method of moment, ground clutter scattering and signal processing method (the bottle neck of the PCL) are available up to now in simulator tool. The digital signal (DSP) processing algorithms are performed both on simulated data and on real data measured at NATO C3 Agency in their Haag experiment. The Institute of Information Theory and Automation of the Academy of Sciences of the Czech Republic takes part on the implementation of the DSP algorithms in FPGA. The paper describes the simulator and signal processing structure and results both on simulated and measured data.

Commentary on "Capturing the Evasive Passive"

ERIC Educational Resources Information Center

Lillo-Martin, Diane; Snyder, William

2009-01-01

Passives has been the focus of much research in language acquisition since the 1970s. It has been clear from this research that young children seldom produce passives spontaneously, particularly "long" or "full" passives with a by-phrase; and they usually perform poorly on experimental tests of the comprehension of passives, especially passives of…

Behavioral and Physiological Findings of Gender Differences in Global-Local Visual Processing

ERIC Educational Resources Information Center

Roalf, David; Lowery, Natasha; Turetsky, Bruce I.

2006-01-01

Hemispheric asymmetries in global-local visual processing are well-established, as are gender differences in cognition. Although hemispheric asymmetry presumably underlies gender differences in cognition, the literature on gender differences in global-local processing is sparse. We employed event related brain potential (ERP) recordings during…

Rasch measurement: the Arm Activity measure (ArmA) passive function sub-scale.

PubMed

Ashford, Stephen; Siegert, Richard J; Alexandrescu, Roxana

2016-01-01

To evaluate the conformity of the Arm Activity measure (ArmA) passive function sub-scale to the Rasch model. A consecutive cohort of patients (n = 92) undergoing rehabilitation, including upper limb rehabilitation and spasticity management, at two specialist rehabilitation units were included. Rasch analysis was used to examine scaling and conformity to the model. Responses were analysed using Rasch unidimensional measurement models (RUMM 2030). The following aspects were considered: overall model and individual item fit statistics and fit residuals, internal reliability, item response threshold ordering, item bias, local dependency and unidimensionality. ArmA contains both active and passive function sub-scales, but in this analysis only the passive function sub-scale was considered. Four of the seven items in the ArmA passive function sub-scale initially had disordered thresholds. These items were rescored to four response options, which resulted in ordered thresholds for all items. Once the items with disordered thresholds had been rescored, item bias was not identified for age, global disability level or diagnosis, but with a small difference in difficulty between males and females for one item of the scale. Local dependency was not observed and the unidimensionality of the sub-scale was supported and good fit to the Rasch model was identified. The person separation index (PSI) was 0.95 indicating that the scale is able to reliably differentiate at least two groups of patients. The ArmA passive function sub-scale was shown in this evaluation to conform to the Rasch model once disordered thresholds had been addressed. Using the logit scores produced by the Rasch model it was possible to convert this back to the original scale range. Implications for Rehabilitation The ArmA passive function sub-scale was shown, in this evaluation, to conform to the Rasch model once disordered thresholds had been addressed and therefore to be a clinically applicable and

Controlling the Local Electronic Properties of Si(553)-Au through Hydrogen Doping

NASA Astrophysics Data System (ADS)

Hogan, C.; Speiser, E.; Chandola, S.; Suchkova, S.; Aulbach, J.; Schäfer, J.; Meyer, S.; Claessen, R.; Esser, N.

2018-04-01

We propose a quantitative and reversible method for tuning the charge localization of Au-stabilized stepped Si surfaces by site-specific hydrogenation. This is demonstrated for Si(553)-Au as a model system by combining density functional theory simulations and reflectance anisotropy spectroscopy experiments. We find that controlled H passivation is a two-step process: step-edge adsorption drives excess charge into the conducting metal chain "reservoir" and renders it insulating, while surplus H recovers metallic behavior. Our approach illustrates a route towards microscopic manipulation of the local surface charge distribution and establishes a reversible switch of site-specific chemical reactivity and magnetic properties on vicinal surfaces.

Surface Passivation in Empirical Tight Binding

NASA Astrophysics Data System (ADS)

He, Yu; Tan, Yaohua; Jiang, Zhengping; Povolotskyi, Michael; Klimeck, Gerhard; Kubis, Tillmann

2016-03-01

Empirical Tight Binding (TB) methods are widely used in atomistic device simulations. Existing TB methods to passivate dangling bonds fall into two categories: 1) Method that explicitly includes passivation atoms is limited to passivation with atoms and small molecules only. 2) Method that implicitly incorporates passivation does not distinguish passivation atom types. This work introduces an implicit passivation method that is applicable to any passivation scenario with appropriate parameters. This method is applied to a Si quantum well and a Si ultra-thin body transistor oxidized with SiO2 in several oxidation configurations. Comparison with ab-initio results and experiments verifies the presented method. Oxidation configurations that severely hamper the transistor performance are identified. It is also shown that the commonly used implicit H atom passivation overestimates the transistor performance.

Strategy for Passivating Char Efficiently at the Pilot Scale

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

Dunning, Timothy C

Fast pyrolysis is a promising pathway for the commercialization of liquid transportation fuels from biomass. Fast pyrolysis is performed at moderate heat (450-600 degrees Celcius) in an oxygen-deficient environment. One of the products of fast pyrolysis is biochar, which is often used as a heat source or as a soil amendment. Biochar is a partially reacted solid that is created in the production of bio-oil during fast pyrolysis. Biochar produced at these conditions contains significant quantities of carbon that adsorb oxygen when exposed to air. Biochar adsorption of oxygen is an exothermic process that may generate sufficient heat for combustionmore » in ambient air. Biochar is also a self-insulating material which compounds the effects of heat generated internally. These factors lead to safety concerns and material handling difficulties. The Thermochemical Process Development Unit at the National Renewable Energy Laboratory operates a pilot plant that may be configured for fast pyrolysis, gasification, and will be introducing catalytic fast pyrolysis capabilities in 2018. The TCPDU designed and installed a system to introduce oxygen to collected biochar systematically for a controlled passivation. Biochar is collected and cooled in an oxygen deficient environment during fast pyrolysis. Oxygen is then introduced to the biochar on a mass flow basis. A sparger imbedded within the biochar sample near the bottom of the bed flows air diluted with nitrogen into the char bed, and excess gasses are removed from the top of the collection drum, above the char bed. Pressure within the collection drum is measured indicating adequate flow through filters. Sample weight is recorded before and after passivation. During passivation, temperature is measured at 18 points within the char bed. Oxygen content and temperature are measured leaving the char bed. Maximum temperature parameters were established to ensure operator safety during biochar passivation. Extensive passivation

Passivation Of High-Temperature Superconductors

NASA Technical Reports Server (NTRS)

Vasquez, Richard P.

1991-01-01

Surfaces of high-temperature superconductors passivated with native iodides, sulfides, or sulfates formed by chemical treatments after superconductors grown. Passivating compounds nearly insoluble in and unreactive with water and protect underlying superconductors from effects of moisture. Layers of cuprous iodide and of barium sulfate grown. Other candidate passivating surface films: iodides and sulfides of bismuth, strontium, and thallium. Other proposed techniques for formation of passivating layers include deposition and gas-phase reaction.

CdCl2 passivation of polycrystalline CdMgTe and CdZnTe absorbers for tandem photovoltaic cells

NASA Astrophysics Data System (ADS)

Swanson, Drew E.; Reich, Carey; Abbas, Ali; Shimpi, Tushar; Liu, Hanxiao; Ponce, Fernando A.; Walls, John M.; Zhang, Yong-Hang; Metzger, Wyatt K.; Sampath, W. S.; Holman, Zachary C.

2018-05-01

As single-junction silicon solar cells approach their theoretical limits, tandems provide the primary path to higher efficiencies. CdTe alloys can be tuned with magnesium (CdMgTe) or zinc (CdZnTe) for ideal tandem pairing with silicon. A II-VI/Si tandem holds the greatest promise for inexpensive, high-efficiency top cells that can be quickly deployed in the market using existing polycrystalline CdTe manufacturing lines combined with mature silicon production lines. Currently, all high efficiency polycrystalline CdTe cells require a chloride-based passivation process to passivate grain boundaries and bulk defects. This research examines the rich chemistry and physics that has historically limited performance when extending Cl treatments to polycrystalline 1.7-eV CdMgTe and CdZnTe absorbers. A combination of transmittance, quantum efficiency, photoluminescence, transmission electron microscopy, and energy-dispersive X-ray spectroscopy clearly reveals that during passivation, Mg segregates and out-diffuses, initially at the grain boundaries but eventually throughout the bulk. CdZnTe exhibits similar Zn segregation behavior; however, the onset and progression is localized to the back of the device. After passivation, CdMgTe and CdZnTe can render a layer that is reduced to predominantly CdTe electro-optical behavior. Contact instabilities caused by inter-diffusion between the layers create additional complications. The results outline critical issues and paths for these materials to be successfully implemented in Si-based tandems and other applications.

CdCl2 Passivation of Polycrystalline CdMgTe and CdZnTe Absorbers for Tandem Photovoltaic Cells

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

Metzger, Wyatt K; Swanson, Drew; Reich, Carey

As single-junction silicon solar cells approach their theoretical limits, tandems provide the primary path to higher efficiencies. CdTe alloys can be tuned with magnesium (CdMgTe) or zinc (CdZnTe) for ideal tandem pairing with silicon. A II-VI/Si tandem holds the greatest promise for inexpensive, high-efficiency top cells that can be quickly deployed in the market using existing polycrystalline CdTe manufacturing lines combined with mature silicon production lines. Currently, all high efficiency polycrystalline CdTe cells require a chloride-based passivation process to passivate grain boundaries and bulk defects. This research examines the rich chemistry and physics that has historically limited performance when extendingmore » Cl treatments to polycrystalline 1.7-eV CdMgTe and CdZnTe absorbers. A combination of transmittance, quantum efficiency, photoluminescence, transmission electron microscopy, and energy-dispersive X-ray spectroscopy clearly reveals that during passivation, Mg segregates and out-diffuses, initially at the grain boundaries but eventually throughout the bulk. CdZnTe exhibits similar Zn segregation behavior; however, the onset and progression is localized to the back of the device. After passivation, CdMgTe and CdZnTe can render a layer that is reduced to predominantly CdTe electro-optical behavior. Contact instabilities caused by inter-diffusion between the layers create additional complications. The results outline critical issues and paths for these materials to be successfully implemented in Si-based tandems and other applications.« less

Passive fetal monitoring sensor

NASA Astrophysics Data System (ADS)

Zuckerwar, Allan J.; Hall, Earl T.; Baker, Donald A.; Bryant, Timothy D.

1992-08-01

An ambulatory, passive sensor for use in a fetal monitoring system is discussed. The invention is comprised of a piezoelectric polymer film, combined with a metallic mounting plate fastened to a belt, and electrically connected to a signal processing unit by means of a shielded cable. The purpose of the sensor is to receive pressure pulses emitted by a fetus inside an expectant mother. Additionally, the monitor will filter out pressure pulses arising from other sources, such as the maternal heart.

Passive fetal monitoring sensor

NASA Astrophysics Data System (ADS)

1990-07-01

The invention is an ambulatory, passive sensor for use in a fetal monitoring system. The invention incorporates piezoelectric polymer film combined with a metallic mounting plate fastened to a belt and electrically connected to a signal processing unit by means of a shielded cable. The purpose of the sensor is to receive pressure pulses emitted from a fetus inside an expectant mother and to provide means for filtering out pressure pulses arising from other sources, such as the maternal heart.

Passive fetal monitoring sensor

NASA Technical Reports Server (NTRS)

Zuckerwar, Allan J. (Inventor); Hall, Earl T. (Inventor); Baker, Donald A. (Inventor); Bryant, Timothy D. (Inventor)

1992-01-01

An ambulatory, passive sensor for use in a fetal monitoring system is discussed. The invention is comprised of a piezoelectric polymer film, combined with a metallic mounting plate fastened to a belt, and electrically connected to a signal processing unit by means of a shielded cable. The purpose of the sensor is to receive pressure pulses emitted by a fetus inside an expectant mother. Additionally, the monitor will filter out pressure pulses arising from other sources, such as the maternal heart.

Visualizing Molecular Diffusion through Passive Permeability Barriers in Cells: Conventional and Novel Approaches

PubMed Central

Lin, Yu-Chun; Phua, Siew Cheng; Lin, Benjamin; Inoue, Takanari

2013-01-01

Diffusion barriers are universal solutions for cells to achieve distinct organizations, compositions, and activities within a limited space. The influence of diffusion barriers on the spatiotemporal dynamics of signaling molecules often determines cellular physiology and functions. Over the years, the passive permeability barriers in various subcellular locales have been characterized using elaborate analytical techniques. In this review, we will summarize the current state of knowledge on the various passive permeability barriers present in mammalian cells. We will conclude with a description of several conventional techniques and one new approach based on chemically-inducible diffusion trap (C-IDT) for probing permeable barriers. PMID:23731778

Techniques for active passivation

DOEpatents

Roscioli, Joseph R.; Herndon, Scott C.; Nelson, Jr., David D.

2016-12-20

In one embodiment, active (continuous or intermittent) passivation may be employed to prevent interaction of sticky molecules with interfaces inside of an instrument (e.g., an infrared absorption spectrometer) and thereby improve response time. A passivation species may be continuously or intermittently applied to an inlet of the instrument while a sample gas stream is being applied. The passivation species may have a highly polar functional group that strongly binds to either water or polar groups of the interfaces, and once bound presents a non-polar group to the gas phase in order to prevent further binding of polar molecules. The instrument may be actively used to detect the sticky molecules while the passivation species is being applied.

Deconfounding the effects of local element spatial heterogeneity and sparsity on processing dominance.

PubMed

Montoro, Pedro R; Luna, Dolores

2009-10-01

Previous studies on the processing of hierarchical patterns (Luna & Montoro, 2008) have shown that altering the spatial relationships between the local elements affected processing dominance by decreasing global advantage. In the present article, the authors examine whether heterogeneity or a sparse distribution of the local elements was the responsible factor for this effect. In Experiments 1 and 2, the distance between the local elements was increased in a similar way, but between-element distance was homogeneous in Experiment 1 and heterogeneous in Experiment 2. In Experiment 3, local elements' size was varied by presenting global patterns composed of similar large or small local elements and of different large and small sizes. The results of the present research showed that, instead of element sparsity, spatial heterogeneity that could change the appearance of the global form as well as the salience of the local elements was the main determiner of impairing global processing.

A novel local anti-colorectal cancer drug delivery system: negative lipidoid nanoparticles with a passive target via a size-dependent pattern

NASA Astrophysics Data System (ADS)

Ding, Weifeng; Wang, Feng; Zhang, Jianfeng; Guo, Yibing; Ju, Shaoqing; Wang, Huimin

2013-09-01

The nontoxic, targeted and effective delivery of nucleic acid drugs remains an important challenge for clinical development. Here, we describe a novel negative lipidoid nanoparticle delivery system, providing entrapment-based transfection agents for local delivery of siRNA to the colorectal cancer focus. The delivery system was synthesized with lipidoid material 98N12-5(1), mPEG2000-C12/C14 glyceride and cholesterol at a desired molar ratio to realize the anionic surface charge of particles, which could alleviate to a larger degree the inflammatory response and immune stimulation of the organism, embodying dramatic biocompatibility. In particular, mPEG2000-C12/C14 glyceride was selected to ameliorate the stability of the delivery system and protection of nucleic acids by extending the tail length of the carbons, crucial also to neutralize the positive charge of 98N12-5(1) to form a resultant anionic particle. In vivo experiments revealed that a particle size of 90 nm perfectly realized a passive target in a size-dependent manner and did not affect the function of the liver and kidneys by a local delivery method, enema. We clarified that the uptake of negative lipidoid nanoparticles internalized through a lipid raft endocytotic pathway with low cytotoxicity, strong biocompatibility and high efficacy. This study suggests that negative lipidoid nanoparticles with enema delivery costitute, uniquely and appropriately, a local anti-colorectal cancer nucleic acid drug delivery platform, and the application of similar modes may be feasible in other therapeutic settings.

A shear localization mechanism for lubricity of amorphous carbon materials

PubMed Central

Ma, Tian-Bao; Wang, Lin-Feng; Hu, Yuan-Zhong; Li, Xin; Wang, Hui

2014-01-01

Amorphous carbon is one of the most lubricious materials known, but the mechanism is not well understood. It is counterintuitive that such a strong covalent solid could exhibit exceptional lubricity. A prevailing view is that lubricity of amorphous carbon results from chemical passivation of dangling bonds on surfaces. Here we show instead that lubricity arises from shear induced strain localization, which, instead of homogeneous deformation, dominates the shearing process. Shear localization is characterized by covalent bond reorientation, phase transformation and structural ordering preferentially in a localized region, namely tribolayer, resulting in shear weakening. We further demonstrate an anomalous pressure induced transition from stick-slip friction to continuous sliding with ultralow friction, due to gradual clustering and layering of graphitic sheets in the tribolayer. The proposed shear localization mechanism sheds light on the mechanism of superlubricity, and would enrich our understanding of lubrication mechanism of a wide variety of amorphous materials. PMID:24412998

Carrier characteristics influence the kinetics of passive drug loading into lipid nanoemulsions.

PubMed

Göke, Katrin; Bunjes, Heike

2018-05-01

Passive loading as a novel screening approach is a material-saving tool for the efficient selection of a suitable colloidal lipid carrier system for poorly water soluble drug candidates. This method comprises incubation of preformed carrier systems with drug powder and subsequent determination of the resulting drug load of the carrier particles after removal of excess drug. For reliable routine use and to obtain meaningful loading results, information on the kinetics of the process is required. Passive loading proceeds via a dissolution-diffusion-based mechanism, where drug surface area and drug water solubility are key parameters for fast passive loading. While the influence of the drug characteristics is mostly understood, the influence of the carrier characteristics remains unknown. The aim of this study was to examine how the lipid nanocarriers' characteristics, i.e. the type of lipid, the lipid content and the particle size, influence the kinetics of passive loading. Fenofibrate was used as model drug and the loading progress was analyzed by UV spectroscopy. The saturation solubility in the nanocarrier particles, i.e. the lipid type, did not influence the passive loading rate constant. Low lipid content in the nanocarrier and a small nanocarrier particle size both increased passive loading speed. Both variations increase the diffusivity of the nanocarrier particles, which is the primary cause for fast loading at these conditions: The quicker the carrier particles diffuse, the higher is the speed of passive loading. The influence of the diffusivity of the lipid nanocarriers and the effect of drug dissolution rate were included in an overall mechanistic model developed for similar processes (A. Balakrishnan, B.D. Rege, G.L. Amidon, J.E. Polli, Surfactant-mediated dissolution: contributions of solubility enhancement and relatively low micelle diffusivity, J. Pharm. Sci. 93 (2004) 2064-2075). The resulting mechanistic model gave a good estimate of the speed of

Large area tunnel oxide passivated rear contact n -type Si solar cells with 21.2% efficiency: Large area tunnel oxide passivated rear contact n -type Si solar cells

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

Tao, Yuguo; Upadhyaya, Vijaykumar; Chen, Chia-Wei

This paper reports on the implementation of carrier-selective tunnel oxide passivated rear contact for high-efficiency screen-printed large area n-type front junction crystalline Si solar cells. It is shown that the tunnel oxide grown in nitric acid at room temperature (25°C) and capped with n+ polysilicon layer provides excellent rear contact passivation with implied open-circuit voltage iVoc of 714mV and saturation current density J0b of 10.3 fA/cm2 for the back surface field region. The durability of this passivation scheme is also investigated for a back-end high temperature process. In combination with an ion-implanted Al2O3-passivated boron emitter and screen-printed front metal grids,more » this passivated rear contact enabled 21.2% efficient front junction Si solar cells on 239 cm2 commercial grade n-type Czochralski wafers.« less

Flow microcapillary plasma mass spectrometry-based investigation of new Al-Cr-Fe complex metallic alloy passivation.

PubMed

Ott, N; Beni, A; Ulrich, A; Ludwig, C; Schmutz, P

2014-03-01

Al-Cr-Fe complex metallic alloys are new intermetallic phases with low surface energy, low friction, and high corrosion resistance down to very low pH values (0-2). Flow microcapillary plasma mass spectrometry under potentiostatic control was used to characterize the dynamic aspect of passivation of an Al-Cr-Fe gamma phase in acidic electrolytes, allowing a better insight on the parameters inducing chemical stability at the oxyhydroxide-solution interface. In sulfuric acid pH 0, low element dissolution rates (in the µg cm(-2) range after 60 min) evidenced the passive state of the Al-Cr-Fe gamma phase with a preferential over-stoichiometric dissolution of Al and Fe cations. Longer air-aging was found to be beneficial for stabilizing the passive film. In chloride-containing electrolytes, ten times higher Al dissolution rates were detected at open-circuit potential (OCP), indicating that the spontaneously formed passive film becomes unstable. However, electrochemical polarization at low passive potentials induces electrical field generated oxide film modification, increasing chemical stability at the oxyhydroxide-solution interface. In the high potential passive region, localized attack is initiated with subsequent active metal dissolution. © 2013 Published by Elsevier B.V.

Passive cavitation imaging with ultrasound arrays

PubMed Central

Salgaonkar, Vasant A.; Datta, Saurabh; Holland, Christy K.; Mast, T. Douglas

2009-01-01

A method is presented for passive imaging of cavitational acoustic emissions using an ultrasound array, with potential application in real-time monitoring of ultrasound ablation. To create such images, microbubble emissions were passively sensed by an imaging array and dynamically focused at multiple depths. In this paper, an analytic expression for a passive image is obtained by solving the Rayleigh–Sommerfield integral, under the Fresnel approximation, and passive images were simulated. A 192-element array was used to create passive images, in real time, from 520-kHz ultrasound scattered by a 1-mm steel wire. Azimuthal positions of this target were accurately estimated from the passive images. Next, stable and inertial cavitation was passively imaged in saline solution sonicated at 520 kHz. Bubble clusters formed in the saline samples were consistently located on both passive images and B-scans. Passive images were also created using broadband emissions from bovine liver sonicated at 2.2 MHz. Agreement was found between the images and source beam shape, indicating an ability to map therapeutic ultrasound beams in situ. The relation between these broadband emissions, sonication amplitude, and exposure conditions are discussed. PMID:20000921

Passive cavitation imaging with ultrasound arrays.

PubMed

Salgaonkar, Vasant A; Datta, Saurabh; Holland, Christy K; Mast, T Douglas

2009-12-01

A method is presented for passive imaging of cavitational acoustic emissions using an ultrasound array, with potential application in real-time monitoring of ultrasound ablation. To create such images, microbubble emissions were passively sensed by an imaging array and dynamically focused at multiple depths. In this paper, an analytic expression for a passive image is obtained by solving the Rayleigh-Sommerfield integral, under the Fresnel approximation, and passive images were simulated. A 192-element array was used to create passive images, in real time, from 520-kHz ultrasound scattered by a 1-mm steel wire. Azimuthal positions of this target were accurately estimated from the passive images. Next, stable and inertial cavitation was passively imaged in saline solution sonicated at 520 kHz. Bubble clusters formed in the saline samples were consistently located on both passive images and B-scans. Passive images were also created using broadband emissions from bovine liver sonicated at 2.2 MHz. Agreement was found between the images and source beam shape, indicating an ability to map therapeutic ultrasound beams in situ. The relation between these broadband emissions, sonication amplitude, and exposure conditions are discussed.

Auditory post-processing in a passive listening task is deficient in Alzheimer's disease.

PubMed

Bender, Stephan; Bluschke, Annet; Dippel, Gabriel; Rupp, André; Weisbrod, Matthias; Thomas, Christine

2014-01-01

To investigate whether automatic auditory post-processing is deficient in patients with Alzheimer's disease and is related to sensory gating. Event-related potentials were recorded during a passive listening task to examine the automatic transient storage of auditory information (short click pairs). Patients with Alzheimer's disease were compared to a healthy age-matched control group. A young healthy control group was included to assess effects of physiological aging. A bilateral frontal negativity in combination with deep temporal positivity occurring 500 ms after stimulus offset was reduced in patients with Alzheimer's disease, but was unaffected by physiological aging. Its amplitude correlated with short-term memory capacity, but was independent of sensory gating in healthy elderly controls. Source analysis revealed a dipole pair in the anterior temporal lobes. Results suggest that auditory post-processing is deficient in Alzheimer's disease, but is not typically related to sensory gating. The deficit could neither be explained by physiological aging nor by problems in earlier stages of auditory perception. Correlations with short-term memory capacity and executive control tasks suggested an association with memory encoding and/or overall cognitive control deficits. An auditory late negative wave could represent a marker of auditory working memory encoding deficits in Alzheimer's disease. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

The combined effects of action observation and passive proprioceptive training on adaptive motor learning.

PubMed

Lei, Yuming; Bao, Shancheng; Wang, Jinsung

2016-09-07

Sensorimotor adaptation can be induced by action observation, and also by passive training. Here, we investigated the effect of a protocol that combined action observation and passive training on visuomotor adaptation, by comparing it with the effect of action observation or passive training alone. Subjects were divided into five conditions during the training session: (1) action observation, in which the subjects watched a video of a model who adapted to a novel visuomotor rotation; (2) proprioceptive training, in which the subject's arm was moved passively to target locations that were associated with desired trajectories; (3) combined training, in which the subjects watched the video of a model during a half of the session and experienced passive movements during the other half; (4) active training, in which the subjects adapted actively to the rotation; and (5) a control condition, in which the subjects did not perform any task. Following that session, all subjects adapted to the same visuomotor rotation. Results showed that the subjects in the combined training condition adapted to the rotation significantly better than those in the observation or proprioceptive training condition, although their performance was not as good as that of those who adapted actively. These findings suggest that although a protocol that combines action observation and passive training consists of all the processes involved in active training (error detection and correction, effector-specific and proprioceptively based reaching movements), these processes in that protocol may work differently as compared to a protocol in which the same processes are engaged actively. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Neuronal correlates of a virtual-reality-based passive sensory P300 network.

PubMed

Chen, Chun-Chuan; Syue, Kai-Syun; Li, Kai-Chiun; Yeh, Shih-Ching

2014-01-01

P300, a positive event-related potential (ERP) evoked at around 300 ms after stimulus, can be elicited using an active or passive oddball paradigm. Active P300 requires a person's intentional response, whereas passive P300 does not require an intentional response. Passive P300 has been used in incommunicative patients for consciousness detection and brain computer interface. Active and passive P300 differ in amplitude, but not in latency or scalp distribution. However, no study has addressed the mechanism underlying the production of passive P300. In particular, it remains unclear whether the passive P300 shares an identical active P300 generating network architecture when no response is required. This study aims to explore the hierarchical network of passive sensory P300 production using dynamic causal modelling (DCM) for ERP and a novel virtual reality (VR)-based passive oddball paradigm. Moreover, we investigated the causal relationship of this passive P300 network and the changes in connection strength to address the possible functional roles. A classical ERP analysis was performed to verify that the proposed VR-based game can reliably elicit passive P300. The DCM results suggested that the passive and active P300 share the same parietal-frontal neural network for attentional control and, underlying the passive network, the feed-forward modulation is stronger than the feed-back one. The functional role of this forward modulation may indicate the delivery of sensory information, automatic detection of differences, and stimulus-driven attentional processes involved in performing this passive task. To our best knowledge, this is the first study to address the passive P300 network. The results of this study may provide a reference for future clinical studies on addressing the network alternations under pathological states of incommunicative patients. However, caution is required when comparing patients' analytic results with this study. For example, the task

Neuronal Correlates of a Virtual-Reality-Based Passive Sensory P300 Network

PubMed Central

Chen, Chun-Chuan; Syue, Kai-Syun; Li, Kai-Chiun; Yeh, Shih-Ching

2014-01-01

P300, a positive event-related potential (ERP) evoked at around 300 ms after stimulus, can be elicited using an active or passive oddball paradigm. Active P300 requires a person’s intentional response, whereas passive P300 does not require an intentional response. Passive P300 has been used in incommunicative patients for consciousness detection and brain computer interface. Active and passive P300 differ in amplitude, but not in latency or scalp distribution. However, no study has addressed the mechanism underlying the production of passive P300. In particular, it remains unclear whether the passive P300 shares an identical active P300 generating network architecture when no response is required. This study aims to explore the hierarchical network of passive sensory P300 production using dynamic causal modelling (DCM) for ERP and a novel virtual reality (VR)-based passive oddball paradigm. Moreover, we investigated the causal relationship of this passive P300 network and the changes in connection strength to address the possible functional roles. A classical ERP analysis was performed to verify that the proposed VR-based game can reliably elicit passive P300. The DCM results suggested that the passive and active P300 share the same parietal-frontal neural network for attentional control and, underlying the passive network, the feed-forward modulation is stronger than the feed-back one. The functional role of this forward modulation may indicate the delivery of sensory information, automatic detection of differences, and stimulus-driven attentional processes involved in performing this passive task. To our best knowledge, this is the first study to address the passive P300 network. The results of this study may provide a reference for future clinical studies on addressing the network alternations under pathological states of incommunicative patients. However, caution is required when comparing patients’ analytic results with this study. For example, the task

Comparison of fMRI data from passive listening and active-response story processing tasks in children.

PubMed

Vannest, Jennifer J; Karunanayaka, Prasanna R; Altaye, Mekibib; Schmithorst, Vincent J; Plante, Elena M; Eaton, Kenneth J; Rasmussen, Jerod M; Holland, Scott K

2009-04-01

To use functional MRI (fMRI) methods to visualize a network of auditory and language-processing brain regions associated with processing an aurally-presented story. We compare a passive listening (PL) story paradigm to an active-response (AR) version including online performance monitoring and a sparse acquisition technique. Twenty children (ages 11-13 years) completed PL and AR story processing tasks. The PL version presented alternating 30-second blocks of stories and tones; the AR version presented story segments, comprehension questions, and 5-second tone sequences, with fMRI acquisitions between stimuli. fMRI data was analyzed using a general linear model approach and paired t-test identifying significant group activation. Both tasks showed activation in the primary auditory cortex, superior temporal gyrus bilaterally, and left inferior frontal gyrus (IFG). The AR task demonstrated more extensive activation, including the dorsolateral prefrontal cortex and anterior/posterior cingulate cortex. Comparison of effect size in each paradigm showed a larger effect for the AR paradigm in a left inferior frontal region-of-interest (ROI). Activation patterns for story processing in children are similar in PL and AR tasks. Increases in extent and magnitude of activation in the AR task are likely associated with memory and attention resources engaged across acquisition intervals.

Mesoscale Elucidation of Surface Passivation in the Li-Sulfur Battery Cathode.

PubMed

Liu, Zhixiao; Mukherjee, Partha P

2017-02-15

The cathode surface passivation caused by Li 2 S precipitation adversely affects the performance of lithium-sulfur (Li-S) batteries. Li 2 S precipitation is a complicated mesoscale process involving adsorption, desorption and diffusion kinetics, which are affected profoundly by the reactant concentration and operating temperature. In this work, a mesoscale interfacial model is presented to study the growth of Li 2 S film on carbon cathode surface. Li 2 S film growth experiences nucleation, isolated Li 2 S island growth and island coalescence. The slow adsorption rate at small S 2- concentration inhibits the formation of nucleation seeds and the lateral growth of Li 2 S islands, which deters surface passivation. An appropriate operating temperature, especially in the medium-to-high temperature range, can also defer surface passivation. Fewer Li 2 S nucleation seeds form in such an operating temperature range, thereby facilitating heterogeneous growth and potentially inhibiting the lateral growth of the Li 2 S film, which may ultimately result in reduced surface passivation. The high specific surface area of the cathode microstructure is expected to mitigate the surface passivation.

Tropospheric Passive Remote Sensing

NASA Technical Reports Server (NTRS)

Keafer, L. S., Jr. (Editor)

1982-01-01

The long term role of airborne/spaceborne passive remote sensing systems for tropospheric air quality research and the identification of technology advances required to improve the performance of passive remote sensing systems were discussed.

RF performances of inductors integrated on localized p+-type porous silicon regions

PubMed Central

2012-01-01

To study the influence of localized porous silicon regions on radiofrequency performances of passive devices, inductors were integrated on localized porous silicon regions, full porous silicon sheet, bulk silicon and glass substrates. In this work, a novel strong, resistant fluoropolymer mask is introduced to localize the porous silicon on the silicon wafer. Then, the quality factors and resonant frequencies obtained with the different substrates are presented. A first comparison is done between the performances of inductors integrated on same-thickness localized and full porous silicon sheet layers. The effect of the silicon regions in the decrease of performances of localized porous silicon is discussed. Then, the study shows that the localized porous silicon substrate significantly reduces losses in comparison with high-resistivity silicon or highly doped silicon bulks. These results are promising for the integration of both passive and active devices on the same silicon/porous silicon hybrid substrate. PMID:23009746

Low temperature cured poly-siloxane passivation for highly reliable a-InGaZnO thin-film transistors

NASA Astrophysics Data System (ADS)

Yoshida, Naofumi; Bermundo, Juan Paolo; Ishikawa, Yasuaki; Nonaka, Toshiaki; Taniguchi, Katsuto; Uraoka, Yukiharu

2018-05-01

Low temperature processable passivation materials are necessary to fabricate highly reliable amorphous InGaZnO (a-IGZO) thin-film transistors (TFT) on organic substrates for flexible device applications. We investigated 3 types of poly-siloxane (Poly-SX) passivation layers fabricated by a solution process and cured at low temperatures (180 °C) for a-IGZO TFTs. This passivation layer greatly improves the stability of the a-IGZO device even after being subjected to positive (PBS) and negative bias stress (NBS). The field effect mobility (μ) of MePhQ504010 passivated on the TFT reached 8.34 cm2/Vs and had a small threshold voltage shift of 0.9 V after PBS, -0.8 V after NBS without the hump phenomenon. Furthermore, we analyzed the hydrogen and hydroxide states in the a-IGZO layer by secondary ion mass spectrometry and X-ray photoelectron spectroscopy to determine the cause of excellent electrical properties despite the curing performed at a low temperature. These results show the potential of the solution processed Poly-SX passivation layer for flexible devices.

Evaluating the Relationship between Equilibrium Passive ...

EPA Pesticide Factsheets

This review evaluates passive sampler uptake of hydrophobic organic contaminants (HOCs) as it relates to organism bioaccumulation in the water column and interstitial water. Fifty-five studies were found where both passive samplers and organism bioaccumulation were used to measured water quality. Of these investigations, 19 provided direct comparisons relating passive sampler concentrations and organism bioaccumulation. Passive sampling polymers included in the review were: low density polyethylene (LDPE); polyoxymethylene (POM); and polydimethylsiloxane (PDMS), and organisms ranged from polychaetes and oligochaetes to bivalves, aquatic insects, and gastropods. Log-linear regressions correlating bioaccumulation (CL) and passive sampler concentration (CPS) were used to assess the strength of observed relationships. In general, the passive sampler concentrations resulted in statistically-significant, logarithmic, predictive relationships, most of which were within one to two orders of magnitude of measured bioaccumulation. Overall, bioaccumulation values were greater than passive sampler concentrations. A mean ratio of CL to CPS was 10.8 ± 18.4 (n = 609) for available data. Given that all studies presented resulted in a strong CL versus CPS relationship suggests that using passive sampling as a surrogate for organism bioaccumulation is viable when biomonitoring organisms are not available. Passive sampling based measurements can provide useful information for ma

Cost-effective parallel optical interconnection module based on fully passive-alignment process

NASA Astrophysics Data System (ADS)

Son, Dong Hoon; Heo, Young Soon; Park, Hyoung-Jun; Kang, Hyun Seo; Kim, Sung Chang

2017-11-01

In optical interconnection technology, high-speed and large data transitions with low error rate and cost reduction are key issues for the upcoming 8K media era. The researchers present notable types of optical manufacturing structures of a four-channel parallel optical module by fully passive alignment, which are able to reduce manufacturing time and cost. Each of the components, such as vertical-cavity surface laser/positive-intrinsic negative-photodiode array, microlens array, fiber array, and receiver (RX)/transmitter (TX) integrated circuit, is integrated successfully using flip-chip bonding, die bonding, and passive alignment with a microscope. Clear eye diagrams are obtained by 25.78-Gb/s (for TX) and 25.7-Gb/s (for RX) nonreturn-to-zero signals of pseudorandom binary sequence with a pattern length of 231 to 1. The measured responsivity and minimum sensitivity of the RX are about 0.5 A/W and ≤-6.5 dBm at a bit error rate (BER) of 10-12, respectively. The optical power margin at a BER of 10-12 is 7.5 dB, and cross talk by the adjacent channel is ≤1 dB.

Local Ownership of Education Policies at the Crossroads between the Active Participation and the Passive Compliance to International Goals

ERIC Educational Resources Information Center

Imaniriho, Dan

2015-01-01

Over the past three decades, perceptions about the role of local population in policy development process have deeply changed. This change is related to the idea promoted by international institutions that the development actions cannot succeed without a strong local ownership and a broad approach that guarantee active participation of local…

Fault identification and localization for Ethernet Passive Optical Network using L-band ASE source and various types of fiber Bragg grating

NASA Astrophysics Data System (ADS)

Naim, Nani Fadzlina; Bakar, A. Ashrif A.; Ab-Rahman, Mohammad Syuhaimi

2018-01-01

This paper presents a centralized and fault localization technique for Ethernet Passive Optical Access Network. This technique employs L-band Amplified Spontaneous Emission (ASE) as the monitoring source and various fiber Bragg Gratings (FBGs) as the fiber's identifier. An FBG with a unique combination of Bragg wavelength, reflectivity and bandwidth is inserted at each distribution fiber. The FBG reflection spectrum will be analyzed using an optical spectrum analyzer (OSA) to monitor the condition of the distribution fiber. Various FBGs reflection spectra is employed to optimize the limited bandwidth of monitoring source, thus allows more fibers to be monitored. Basically, one Bragg wavelength is shared by two distinct FBGs with different reflectivity and bandwidth. The experimental result shows that the system is capable to monitor up to 32 customers with OSNR value of ∼1.2 dB and monitoring power received of -24 dBm. This centralized and simple monitoring technique demonstrates a low power, cost efficient and low bandwidth requirement system.

[A cross sectional study of passive smoking of non-smoking women and analysis of influence factors on women passive smoking].

PubMed

Han, Jing-Xiu; Ma, Ling; Zhang, Hong-Wei; Liu, Xi; Zheng, Su-hua; Gan, De-kun; Fang, Jun

2006-09-01

To fund out the state of passive smoking of non-smoking women and search for measures of controlling women passive smoking. 3500 non-smoking women in Beijing, Shanghai, Chengdu city were interviewed. Analyses were performed by chi2 test Fisher test and ANOVA test. 92.7% passive smoking women exposure to ETS at home, 40.8% at workplace. 38.9% exposed to ETS from birthday, and 42.3% from 18 - 30 age. The average exposure time of passive smoking is (1.17 +/- 1.10) hours per day. The proportion of passive-smoking time over 2 hours at home is higher than work place. In passive-smoking group, the proportion of 30 - 50 age group, secondary education, married, merchant/service, principal of units, and manufacture/transport workers were higher than non-smoking group. 97.5% think that passive smoking is harmful to health, and the proportion of thinking passive smoking has severe harm to health in non-passive-smoking group is higher than passive-smoking group. 70.0% open windows when someone smokes around her, but only 16.9% ask the smokers do not smoke around her forwardly. Suppose that someone were smoking around yourself, the consciousness of avoiding passive smoking forwardly in non-passive-smoking group is stronger than passive-smoking group. 95.1% believe the content of smoking-harm propagandized by medium. The main places of controlling passive smoking are the home and the department, commerce, service, and manufacture/ transport workplace. The rate of passive smoking was influenced by the consciousness of the serious level of harms by passive smoking. Propagandizing the serious harm of passive smoking by medium and strengthening the consciousness of avoiding passive smoking were one of feasible measures to lower the rate of smoking and passive smoking.

Multiple mechanisms quench passive spiral galaxies

NASA Astrophysics Data System (ADS)

Fraser-McKelvie, Amelia; Brown, Michael J. I.; Pimbblet, Kevin; Dolley, Tim; Bonne, Nicolas J.

2018-02-01

We examine the properties of a sample of 35 nearby passive spiral galaxies in order to determine their dominant quenching mechanism(s). All five low-mass (M⋆ < 1 × 1010 M⊙) passive spiral galaxies are located in the rich Virgo cluster. This is in contrast to low-mass spiral galaxies with star formation, which inhabit a range of environments. We postulate that cluster-scale gas stripping and heating mechanisms operating only in rich clusters are required to quench low-mass passive spirals, and ram-pressure stripping and strangulation are obvious candidates. For higher mass passive spirals, while trends are present, the story is less clear. The passive spiral bar fraction is high: 74 ± 15 per cent, compared with 36 ± 5 per cent for a mass, redshift and T-type matched comparison sample of star-forming spiral galaxies. The high mass passive spirals occur mostly, but not exclusively, in groups, and can be central or satellite galaxies. The passive spiral group fraction of 74 ± 15 per cent is similar to that of the comparison sample of star-forming galaxies at 61 ± 7 per cent. We find evidence for both quenching via internal structure and environment in our passive spiral sample, though some galaxies have evidence of neither. From this, we conclude no one mechanism is responsible for quenching star formation in passive spiral galaxies - rather, a mixture of mechanisms is required to produce the passive spiral distribution we see today.

Matched Field Processing Based on Least Squares with a Small Aperture Hydrophone Array.

PubMed

Wang, Qi; Wang, Yingmin; Zhu, Guolei

2016-12-30

The receiver hydrophone array is the signal front-end and plays an important role in matched field processing, which usually covers the whole water column from the sea surface to the bottom. Such a large aperture array is very difficult to realize. To solve this problem, an approach called matched field processing based on least squares with a small aperture hydrophone array is proposed, which decomposes the received acoustic fields into depth function matrix and amplitudes of the normal modes at the beginning. Then all the mode amplitudes are estimated using the least squares in the sense of minimum norm, and the amplitudes estimated are used to recalculate the received acoustic fields of the small aperture array, which means the recalculated ones contain more environmental information. In the end, lots of numerical experiments with three small aperture arrays are processed in the classical shallow water, and the performance of matched field passive localization is evaluated. The results show that the proposed method can make the recalculated fields contain more acoustic information of the source, and the performance of matched field passive localization with small aperture array is improved, so the proposed algorithm is proved to be effective.

Matched Field Processing Based on Least Squares with a Small Aperture Hydrophone Array

PubMed Central

Wang, Qi; Wang, Yingmin; Zhu, Guolei

2016-01-01

The receiver hydrophone array is the signal front-end and plays an important role in matched field processing, which usually covers the whole water column from the sea surface to the bottom. Such a large aperture array is very difficult to realize. To solve this problem, an approach called matched field processing based on least squares with a small aperture hydrophone array is proposed, which decomposes the received acoustic fields into depth function matrix and amplitudes of the normal modes at the beginning. Then all the mode amplitudes are estimated using the least squares in the sense of minimum norm, and the amplitudes estimated are used to recalculate the received acoustic fields of the small aperture array, which means the recalculated ones contain more environmental information. In the end, lots of numerical experiments with three small aperture arrays are processed in the classical shallow water, and the performance of matched field passive localization is evaluated. The results show that the proposed method can make the recalculated fields contain more acoustic information of the source, and the performance of matched field passive localization with small aperture array is improved, so the proposed algorithm is proved to be effective. PMID:28042828

Chinese Passives: Transformational or Lexical?

ERIC Educational Resources Information Center

Zhang, Jiuwu; Wen, Xiaohong

Analysis of Chinese passive constructions indicates two types. The first is a verbal or syntactic passive because it is derived through a transformational rule. The second is a lexical passive that has certain properties in common with the predicate adjectives in both Chinese and English and is derived through the semantic function and in lexical…

Evidence Integration in Natural Acoustic Textures during Active and Passive Listening

PubMed Central

Rupp, Andre; Celikel, Tansu

2018-01-01

Abstract Many natural sounds can be well described on a statistical level, for example, wind, rain, or applause. Even though the spectro-temporal profile of these acoustic textures is highly dynamic, changes in their statistics are indicative of relevant changes in the environment. Here, we investigated the neural representation of change detection in natural textures in humans, and specifically addressed whether active task engagement is required for the neural representation of this change in statistics. Subjects listened to natural textures whose spectro-temporal statistics were modified at variable times by a variable amount. Subjects were instructed to either report the detection of changes (active) or to passively listen to the stimuli. A subset of passive subjects had performed the active task before (passive-aware vs passive-naive). Psychophysically, longer exposure to pre-change statistics was correlated with faster reaction times and better discrimination performance. EEG recordings revealed that the build-up rate and size of parieto-occipital (PO) potentials reflected change size and change time. Reduced effects were observed in the passive conditions. While P2 responses were comparable across conditions, slope and height of PO potentials scaled with task involvement. Neural source localization identified a parietal source as the main contributor of change-specific potentials, in addition to more limited contributions from auditory and frontal sources. In summary, the detection of statistical changes in natural acoustic textures is predominantly reflected in parietal locations both on the skull and source level. The scaling in magnitude across different levels of task involvement suggests a context-dependent degree of evidence integration. PMID:29662943

Evidence Integration in Natural Acoustic Textures during Active and Passive Listening.

PubMed

Górska, Urszula; Rupp, Andre; Boubenec, Yves; Celikel, Tansu; Englitz, Bernhard

2018-01-01

Many natural sounds can be well described on a statistical level, for example, wind, rain, or applause. Even though the spectro-temporal profile of these acoustic textures is highly dynamic, changes in their statistics are indicative of relevant changes in the environment. Here, we investigated the neural representation of change detection in natural textures in humans, and specifically addressed whether active task engagement is required for the neural representation of this change in statistics. Subjects listened to natural textures whose spectro-temporal statistics were modified at variable times by a variable amount. Subjects were instructed to either report the detection of changes (active) or to passively listen to the stimuli. A subset of passive subjects had performed the active task before (passive-aware vs passive-naive). Psychophysically, longer exposure to pre-change statistics was correlated with faster reaction times and better discrimination performance. EEG recordings revealed that the build-up rate and size of parieto-occipital (PO) potentials reflected change size and change time. Reduced effects were observed in the passive conditions. While P2 responses were comparable across conditions, slope and height of PO potentials scaled with task involvement. Neural source localization identified a parietal source as the main contributor of change-specific potentials, in addition to more limited contributions from auditory and frontal sources. In summary, the detection of statistical changes in natural acoustic textures is predominantly reflected in parietal locations both on the skull and source level. The scaling in magnitude across different levels of task involvement suggests a context-dependent degree of evidence integration.

Germanium detector passivated with hydrogenated amorphous germanium

DOEpatents

Hansen, William L.; Haller, Eugene E.

1986-01-01

Passivation of predominantly crystalline semiconductor devices (12) is provided for by a surface coating (21) of sputtered hydrogenated amorphous semiconductor material. Passivation of a radiation detector germanium diode, for example, is realized by sputtering a coating (21) of amorphous germanium onto the etched and quenched diode surface (11) in a low pressure atmosphere of hydrogen and argon. Unlike prior germanium diode semiconductor devices (12), which must be maintained in vacuum at cryogenic temperatures to avoid deterioration, a diode processed in the described manner may be stored in air at room temperature or otherwise exposed to a variety of environmental conditions. The coating (21) compensates for pre-existing undesirable surface states as well as protecting the semiconductor device (12) against future impregnation with impurities.

Thick-Filament Strain and Interfilament Spacing in Passive Muscle: Effect of Titin-Based Passive Tension

PubMed Central

Irving, Thomas; Wu, Yiming; Bekyarova, Tanya; Farman, Gerrie P.; Fukuda, Norio; Granzier, Henk

2011-01-01

We studied the effect of titin-based passive tension on sarcomere structure by simultaneously measuring passive tension and low-angle x-ray diffraction patterns on passive fiber bundles from rabbit skinned psoas muscle. We used a stretch-hold-release protocol with measurement of x-ray diffraction patterns at various passive tension levels during the hold phase before and after passive stress relaxation. Measurements were performed in relaxing solution without and with dextran T-500 to compress the lattice toward physiological levels. The myofilament lattice spacing was measured in the A-band (d1,0) and Z-disk (dZ) regions of the sarcomere. The axial spacing of the thick-filament backbone was determined from the sixth myosin meridional reflection (M6) and the equilibrium positions of myosin heads from the fourth myosin layer line peak position and the I1,1/I1,0 intensity ratio. Total passive tension was measured during the x-ray experiments, and a differential extraction technique was used to determine the relations between collagen- and titin-based passive tension and sarcomere length. Within the employed range of sarcomere lengths (∼2.2–3.4 μm), titin accounted for >80% of passive tension. X-ray results indicate that titin compresses both the A-band and Z-disk lattice spacing with viscoelastic behavior when fibers are swollen after skinning, and elastic behavior when the lattice is reduced with dextran. Titin also increases the axial thick-filament spacing, M6, in an elastic manner in both the presence and absence of dextran. No changes were detected in either I1,1/I1,0 or the position of peaks on the fourth myosin layer line during passive stress relaxation. Passive tension and M6 measurements were converted to thick-filament compliance, yielding a value of ∼85 m/N, which is several-fold larger than the thick-filament compliance determined by others during the tetanic tension plateau of activated intact muscle. This difference can be explained by the fact

Global/local processing style: Explaining the relationship between trait anxiety and binge eating.

PubMed

Becker, Kendra R; Plessow, Franziska; Coniglio, Kathryn A; Tabri, Nassim; Franko, Debra L; Zayas, Lazaro V; Germine, Laura; Thomas, Jennifer J; Eddy, Kamryn T

2017-11-01

Anxiety is a risk factor for disordered eating, but the mechanisms by which anxiety promotes disordered eating are poorly understood. One possibility is local versus global cognitive processing style, defined as a relative tendency to attend to details at the expense of the "big picture." Anxiety may narrow attention, in turn, enhancing local and/or compromising global processing. We examined relationships between global/local processing style, anxiety, and disordered eating behaviors in a transdiagnostic outpatient clinical sample. We hypothesized that local (vs. global) processing bias would mediate the relationship between anxiety and disordered eating behaviors. Ninety-three participants completed the eating disorder examination-questionnaire (EDE-Q), State-Trait Anxiety Inventory (STAI)-trait subscale, and the Navon task (a test of processing style in which large letters are composed of smaller letters both congruent and incongruent with the large letter). The sample was predominantly female (95%) with a mean age of 27.4 years (SD = 12.1 years). Binge eating, but not fasting, purging, or excessive exercise, was correlated with lower levels of global processing style. There was a significant indirect effect between anxiety and binge eating via reduced global level global/local processing. In individuals with disordered eating, being more generally anxious may encourage a detailed-oriented bias, preventing individuals from maintaining the bigger picture and making them more likely to engage in maladaptive behaviors (e.g., binge eating). © 2017 Wiley Periodicals, Inc.

Global/local processing style: Explaining the relationship between trait anxiety and binge eating

PubMed Central

Becker, Kendra R.; Plessow, Franziska; Coniglio, Kathryn A.; Tabri, Nassim; Franko, Debra L; Zayas, Lazaro V.; Germine, Laura; Thomas, Jennifer J.; Eddy, Kamryn T.

2018-01-01

Objective Anxiety is a risk factor for disordered eating, but the mechanisms by which anxiety promotes disordered eating are poorly understood. One possibility is local versus global cognitive processing style, defined as a relative tendency to attend to details at the expense of the “big picture.” Anxiety may narrow attention, in turn, enhancing local and/or compromising global processing. We examined relationships between global/local processing style, anxiety, and disordered eating behaviors in a transdiagnostic outpatient clinical sample. We hypothesized that local (vs. global) processing bias would mediate the relationship between anxiety and disordered eating behaviors. Method Ninety-three participants completed the eating disorder examination—questionnaire (EDE-Q), State-Trait Anxiety Inventory (STAI)—trait subscale, and the Navon task (a test of processing style in which large letters are composed of smaller letters both congruent and incongruent with the large letter). The sample was predominantly female (95%) with a mean age of 27.4 years (SD = 12.1 years). Results Binge eating, but not fasting, purging, or excessive exercise, was correlated with lower levels of global processing style. There was a significant indirect effect between anxiety and binge eating via reduced global level global/local processing. Discussion In individuals with disordered eating, being more generally anxious may encourage a detailed-oriented bias, preventing individuals from maintaining the bigger picture and making them more likely to engage in maladaptive behaviors (e.g., binge eating). PMID:28963792

Localization in covariance matrices of coupled heterogenous Ornstein-Uhlenbeck processes

NASA Astrophysics Data System (ADS)

Barucca, Paolo

2014-12-01

We define a random-matrix ensemble given by the infinite-time covariance matrices of Ornstein-Uhlenbeck processes at different temperatures coupled by a Gaussian symmetric matrix. The spectral properties of this ensemble are shown to be in qualitative agreement with some stylized facts of financial markets. Through the presented model formulas are given for the analysis of heterogeneous time series. Furthermore evidence for a localization transition in eigenvectors related to small and large eigenvalues in cross-correlations analysis of this model is found, and a simple explanation of localization phenomena in financial time series is provided. Finally we identify both in our model and in real financial data an inverted-bell effect in correlation between localized components and their local temperature: high- and low-temperature components are the most localized ones.

Behavior of flavonols and carotenoids of minimally processed kale leaves during storage in passive modified atmosphere packaging.

PubMed

Kobori, C N; Huber, L S; Sarantópoulos, C I G L; Rodriguez-Amaya, D B

2011-03-01

Minimally processed kale leaves were packed in passive modified atmosphere and stored at 3 conditions: 1 °C in the dark and 11 °C with or without light exposure. The products were evaluated during storage in terms of headspace gas composition, sensory attributes, flavonol, and carotenoid contents. The sensory quality decreased slightly during 17 d at 1 °C in the dark. At 11 °C, the vegetable shelf life was predicted to be 6 d in the dark and 3 d with light. Quercetin and kaempferol were stable during storage for 15 d at 1 °C in the absence of light. At 11 °C in the dark, quercetin was stable during 10 d, increasing slightly on the 8th day. Kaempferol decreased up to the 5th day but increased on the 8th day, decreasing again on the 10th day. After 5 d at 11 °C under light, the flavonol levels were significantly higher than those of the initial values. Neoxanthin and violaxanthin did not change significantly after 15 d at 1 °C in the dark. Lutein and β-carotene, however, decreased 7.1% and 11.3%, respectively. At 11 °C in the dark, neoxanthin, violaxanthin, lutein, and β-carotene decreased 16.1%, 13.2%, 24.1%, and 23.7% after 10 d, respectively. At 11 °C under light, neoxanthin and lutein had a slight increase while violaxanthin and β-carotene decreased 23.1% and 16.5% after 5 d. Practical Application:  Passive modified atmosphere packaging together with refrigeration can extend the shelf life of minimally processed kale, retaining the health-promoting compounds, flavonols and carotenoids. Quercetin, kaempferol, neoxanthin, and violaxanthin are stable and lutein and β-carotene slightly reduced.

Visualizing molecular diffusion through passive permeability barriers in cells: conventional and novel approaches.

PubMed

Lin, Yu-Chun; Phua, Siew Cheng; Lin, Benjamin; Inoue, Takanari

2013-08-01

Diffusion barriers are universal solutions for cells to achieve distinct organizations, compositions, and activities within a limited space. The influence of diffusion barriers on the spatiotemporal dynamics of signaling molecules often determines cellular physiology and functions. Over the years, the passive permeability barriers in various subcellular locales have been characterized using elaborate analytical techniques. In this review, we will summarize the current state of knowledge on the various passive permeability barriers present in mammalian cells. We will conclude with a description of several conventional techniques and one new approach based on chemically inducible diffusion trap (CIDT) for probing permeable barriers. Copyright © 2013 Elsevier Ltd. All rights reserved.

Simultaneous 3D tracking of passive tracers and microtubule bundles in an active gel

NASA Astrophysics Data System (ADS)

Fan, Yi; Breuer, Kenneth S.; Fluids Team

Kinesin-driven microtubule bundles generate a spontaneous flow in unconfined geometries. They exhibit properties of active matter, including the emergence of collective motion, reduction of apparent viscosity and consumption of local energy. Here we present results from 3D tracking of passive tracers (using Airy rings and 3D scanning) synchronized with 3D measurement of the microtubule bundles motion. This technique is applied to measure viscosity variation and collective flow in a confined geometry with particular attention paid to the self-pumping system recently reported by Wu et al. (2016). Results show that the viscosity in an equilibrium microtubule network is around half that of the isotropic unbundled microtubule solution. Cross-correlations of the active microtubule network and passive tracers define a neighborhood around microtubule bundles in which passive tracers are effectively transported. MRSEC NSF.

26 CFR 1.1398-1 - Treatment of passive activity losses and passive activity credits in individuals' title 11 cases.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 11 2010-04-01 2010-04-01 true Treatment of passive activity losses and passive... to Individuals' Title 11 Cases § 1.1398-1 Treatment of passive activity losses and passive activity... and rules of general application. For purposes of this section— (1) Passive activity and former...

Directional, passive liquid transport: the Texas horned lizard as a model for a biomimetic ‘liquid diode’

PubMed Central

Comanns, Philipp; Buchberger, Gerda; Buchsbaum, Andreas; Baumgartner, Richard; Kogler, Alexander; Bauer, Siegfried; Baumgartner, Werner

2015-01-01

Moisture-harvesting lizards such as the Texas horned lizard (Iguanidae: Phrynosoma cornutum) live in arid regions. Special skin adaptations enable them to access water sources such as moist sand and dew: their skin is capable of collecting and transporting water directionally by means of a capillary system between the scales. This fluid transport is passive, i.e. requires no external energy, and directs water preferentially towards the lizard's snout. We show that this phenomenon is based on geometric principles, namely on a periodic pattern of interconnected half-open capillary channels that narrow and widen. Following a biomimetic approach, we used these principles to develop a technical prototype design. Building upon the Young–Laplace equation, we derived a theoretical model for the local behaviour of the liquid in such capillaries. We present a global model for the penetration velocity validated by experimental data. Artificial surfaces designed in accordance with this model prevent liquid flow in one direction while sustaining it in the other. Such passive directional liquid transport could lead to process improvements and reduction of resources in many technical applications. PMID:26202685

Cultural Variations in Global versus Local Processing: A Developmental Perspective

ERIC Educational Resources Information Center

Oishi, Shigehiro; Jaswal, Vikram K.; Lillard, Angeline S.; Mizokawa, Ai; Hitokoto, Hidefumi; Tsutsui, Yoshiro

2014-01-01

We conducted 3 studies to explore cultural differences in global versus local processing and their developmental trajectories. In Study 1 ("N" = 363), we found that Japanese college students were less globally oriented in their processing than American or Argentine participants. We replicated this effect in Study 2 ("N" =…

Postural vascular response in human skin: passive and active reactions to alteration of transmural pressure.

PubMed

Jepsen, H; Gaehtgens, P

1993-09-01

Laser-Doppler (LD) fluxmetry was performed in the palmar finger skin of healthy subjects to study the mechanisms contributing to the postural vascular response. Local transmural pressure in the skin blood vessels of the region studied was altered for 1 min in two experimental series either by passive movement of the arm to different vertical hand positions relative to heart level or by application of external pressure (-120-180 mmHg) to the finger. Heart and respiratory rate, arterial blood pressure, and LD flux in the contralateral finger (kept at heart level) were measured. The measurements suggest a compound reaction of local (myogenic) and systemic (neurogenic) mechanisms: the local regulatory component appears as a graded active vascular response elicited by passive vessel distension or compression. A systemic component, associated with a single deep inspiration, is frequently observed during the actual movement of the arm. In addition, prolonged holding of the test hand in a given vertical position also elicits a delayed vascular response in the control hand at heart level, which may be generated by volume receptors in the intrathoracic low-pressure system.

[Does the Fragmented Images Test measure locally oriented visual processing in autism spectrum disorders?].

PubMed

Scheurich, Armin; Fellgiebel, Andreas; Müller, Mattias J; Poustka, Fritz; Bölte, Sven

2010-03-01

The cognitive phenotype of autism spectrum disorders (ASD) is characterized among other things by local processing (weak central coherence). It was examined whether a test that measures identification of fragmented pictures (FBT) is able to seize this preference for local processing. The FBT performance of 15 patients with ASD, 16 with depression, 16 with schizophrenia and of 16 control subjects was compared. In addition, two tests well known to be sensitive to local processing were assessed, namely the Embedded Figures Test (EFT) and the Block Design Test (BDT). ASD patients demonstrated a preference for local processing. Difficulties in global processing, or more specifically in gestalt perception (FBT), were accompanied by good performance on the EFT and BDT as expected. Controlling for age and nonverbal intelligence (ANCOVA) reduced differences to trends. However, the calculation of difference scores (i.e., subtraction of FBT from EFT performance) resulted in significant differences between ASD and control groups even after controlling for of age and intelligence. The FBT is a suitable exploratory test of local visual processing in ASD. In particular, a difference criterion can be generated (FBT vs. EFT) that discriminates between ASD and clinical as well as healthy control groups.

Direct metallization local Al-back surface field for high efficiency screen printed crystalline silicon solar cells.

PubMed

Lee, Jonghwan; Park, Cheolmin; Dao, Vinh Ai; Lee, Youn-Jung; Ryu, Kyungyul; Choi, Gyuho; Kim, Bonggi; Ju, Minkyu; Jeong, Chaehwan; Yi, Junsin

2013-11-01

In this paper, we present a detailed study on the local back contact (LBC) formation of rear-surface-passivated silicon solar cells, where both the LBC opening and metallization are realized by one-step alloying of a dot of fine pattern screen-printed aluminum paste with the silicon substrate. Based on energy dispersive spectrometer (EDS) and scanning electron microscopy (SEM) characterizations, we suggest that the aluminum distribution and the silicon concentration determine the local-back-surface-field (Al-p+) layer thickness, resistivity of the Al-p+ and hence the quality of the Al-p+ formation. The highest penetration of silicon concentration of 78.17% in aluminum resulted in the formation of a 5 microm-deep Al-p+ layer, and the minimum LBC resistivity of 0.92 x 10-6 omega cm2. The degradation of the rear-surface passivation due to high temperature of the LBC formation process can be fully recovered by forming gas annealing (FGA) at temperature and hydrogen content of 450 degrees C and 15%, respectively. The application of the optimized LBC of rear-surface-passivated by a dot of fine pattern screen(-) printed aluminum paste resulted in efficiency of up to 19.98% for the p-type czochralski (CZ) silicon wafers with 10.24 cm2 cell size at 649 mV open circuit voltage. By FGA for rear-surface passivation recovery, efficiencies up to 20.35% with a V(OC) of 662 mV, FF of 82%, and J(SC) of 37.5 mA/cm2 were demonstrated.

Confocal imaging to quantify passive transport across biomimetic lipid membranes.

PubMed

Li, Su; Hu, Peichi; Malmstadt, Noah

2010-09-15

The ability of a molecule to pass through the plasma membrane without the aid of any active cellular mechanisms is central to that molecule's pharmaceutical characteristics. Passive transport has been understood in the context of Overton's rule, which states that more lipophilic molecules cross membrane lipid bilayers more readily. Existing techniques for measuring passive transport lack reproducibility and are hampered by the presence of an unstirred layer (USL) that dominates transport across the bilayer. This report describes assays based on spinning-disk confocal microscopy (SDCM) of giant unilamellar vesicles (GUVs) that allow for the detailed investigation of passive transport processes and mechanisms. This approach allows the concentration field to be directly observed, allowing membrane permeability to be determined easily from the transient concentration profile data. A series of molecules of increasing hydrophilicity was constructed, and the transport of these molecules into GUVs was observed. The observed permeability trend is consistent with Overton's rule. However, the values measured depart from the simple partition-diffusion proportionality model of passive transport. This technique is easy to implement and has great promise as an approach to measure membrane transport. It is optimally suited to precise quantitative measurements of the dependence of passive transport on membrane properties.

On the Vertical Distribution of Local and Remote Sources of Water for Precipitation

NASA Technical Reports Server (NTRS)

Bosilovich, Michael G.

2001-01-01

The vertical distribution of local and remote sources of water for precipitation and total column water over the United States are evaluated in a general circulation model simulation. The Goddard Earth Observing System (GEOS) general circulation model (GCM) includes passive constituent tracers to determine the geographical sources of the water in the column. Results show that the local percentage of precipitable water and local percentage of precipitation can be very different. The transport of water vapor from remote oceanic sources at mid and upper levels is important to the total water in the column over the central United States, while the access of locally evaporated water in convective precipitation processes is important to the local precipitation ratio. This result resembles the conceptual formulation of the convective parameterization. However, the formulations of simple models of precipitation recycling include the assumption that the ratio of the local water in the column is equal to the ratio of the local precipitation. The present results demonstrate the uncertainty in that assumption, as locally evaporated water is more concentrated near the surface.

Deep-Reaching Hydrodynamic Flow Confinement: Micrometer-Scale Liquid Localization for Open Substrates With Topographical Variations.

PubMed

Oskooei, Ali; Kaigala, Govind V

2017-06-01

We present a method for nonintrusive localization and reagent delivery on immersed biological samples with topographical variation on the order of hundreds of micrometers. Our technique, which we refer to as the deep-reaching hydrodynamic flow confinement (DR-HFC), is simple and passive: it relies on a deep-reaching hydrodynamic confinement delivered through a simple microfluidic probe design to perform localized microscale alterations on substrates as deep as 600 μm. Designed to scan centimeter-scale areas of biological substrates, our method passively prevents sample intrusion by maintaining a large gap between the probe and the substrate. The gap prevents collision of the probe and the substrate and reduces the shear stress experienced by the sample. We present two probe designs: linear and annular DR-HFC. Both designs comprise a reagent-injection aperture and aspiration apertures that serve to confine the reagent. We identify the design parameters affecting reagent localization and depth by DR-HFC and study their individual influence on the operation of DR-HFC numerically. Using DR-HFC, we demonstrate localized binding of antihuman immunoglobulin G (IgG) onto an activated substrate at various depths from 50 to 600 μm. DR-HFC provides a readily implementable approach for noninvasive processing of biological samples applicable to the next generation of diagnostic and bioanalytical devices.

Human motion tracking by temporal-spatial local gaussian process experts.

PubMed

Zhao, Xu; Fu, Yun; Liu, Yuncai

2011-04-01

Human pose estimation via motion tracking systems can be considered as a regression problem within a discriminative framework. It is always a challenging task to model the mapping from observation space to state space because of the high-dimensional characteristic in the multimodal conditional distribution. In order to build the mapping, existing techniques usually involve a large set of training samples in the learning process which are limited in their capability to deal with multimodality. We propose, in this work, a novel online sparse Gaussian Process (GP) regression model to recover 3-D human motion in monocular videos. Particularly, we investigate the fact that for a given test input, its output is mainly determined by the training samples potentially residing in its local neighborhood and defined in the unified input-output space. This leads to a local mixture GP experts system composed of different local GP experts, each of which dominates a mapping behavior with the specific covariance function adapting to a local region. To handle the multimodality, we combine both temporal and spatial information therefore to obtain two categories of local experts. The temporal and spatial experts are integrated into a seamless hybrid system, which is automatically self-initialized and robust for visual tracking of nonlinear human motion. Learning and inference are extremely efficient as all the local experts are defined online within very small neighborhoods. Extensive experiments on two real-world databases, HumanEva and PEAR, demonstrate the effectiveness of our proposed model, which significantly improve the performance of existing models.

Process optimization of joining by upset bulging with local heating

NASA Astrophysics Data System (ADS)

Rusch, Michael; Almohallami, Amer; Sviridov, Alexander; Bonk, Christian; Behrens, Bernd-Arno; Bambach, Markus

2017-10-01

Joining by upset bulging is a mechanical joining method where axial load is applied to a tube to form two revolving bulges, which clamp the parts to be joined and create a force and form fit. It can be used to join tubes with other structures such as sheets, plates, tubes or profiles of the same or different materials. Other processes such as welding are often limited in joining multi-material assemblies or high-strength materials. With joining by upset bulging at room temperature, the main drawback is the possible initiation of damage (cracks) in the inner buckling zone because of high local stresses and strains. In this paper, a method to avoid the formation of cracks is introduced. Before forming the bulge the tube is locally heated by an induction coil. For the construction steel (E235+N) a maximum temperature of 700 °C was used to avoid phase transformation. For the numerical study of the process the mechanical properties of the tube material were examined at different temperatures and strain rates to determine its flow curves. A parametrical FE model was developed to simulate the bulging process with local heating. Experiments with local heating were executed and metallographic studies of the bulging area were conducted. While specimens heated to 500 °C showed small cracks left, damage-free flanges could be created at 600 and 700 °C. Static testing of damage-free bulges showed improvements in tensile strength and torsion strength compared to bulges formed at room-temperature, while bending and compression behavior remained nearly unchanged. In cyclic testing the locally heated specimens underwent about 3.7 times as many cycles before failure as the specimens formed at room temperature.

Ensuring Effective Curriculum Approval Processes: A Guide for Local Senates

ERIC Educational Resources Information Center

Academic Senate for California Community Colleges, 2016

2016-01-01

Curriculum is the heart of the mission of every college. College curriculum approval processes have been established to ensure that rigorous, high quality curriculum is offered that meets the needs of students. While some concerns may exist regarding the effectiveness and efficiency of local curriculum processes, all participants in the process…

A field evaluation of a SO 2 passive sampler in tropical industrial and urban air

NASA Astrophysics Data System (ADS)

Cruz, Lícia P. S.; Campos, Vânia P.; Silva, Adriana M. C.; Tavares, Tania M.

Passive samplers have been widely used for over 30 years in the measurement of personal exposure to vapours and gases in the workplace. These samplers have just recently been applied in the monitoring of ambient air, which presents concentrations that are normally much smaller than those found in occupational environments. The locally constructed passive sampler was based on gas molecular diffusion through static air layer. The design used minimizes particle interference and turbulent diffusion. After exposure, the SO 2 trapped in impregnated filters with Na 2CO 3 was extracted by means of an ultrasonic bath, for 15 min, using 1.0×10 -2 mol L -1 H 2O 2. It was determined as SO 4-2 by ion chromatography. The performance of the passive sampler was evaluated at different exposure periods, being applied in industrial and urban areas. Method precision as relative standard deviation for three simultaneously applied passive samplers was within 10%. Passive sampling, when compared to active monitoring methods under real conditions, used in urban and industrial areas, showed an overall accuracy of 15%. A statistical comparison with an active method was performed to demonstrate the validity of the passive method. Sampler capacity varied between 98 and 421 μg SO 2 m -3 for exposure periods of one month and one week, respectively, which allows its use in highly polluted areas.

Enhanced Local Processing of Dynamic Visual Information in Autism: Evidence from Speed Discrimination

ERIC Educational Resources Information Center

Chen, Y.; Norton, D. J.; McBain, R.; Gold, J.; Frazier, J. A.; Coyle, J. T.

2012-01-01

An important issue for understanding visual perception in autism concerns whether individuals with this neurodevelopmental disorder possess an advantage in processing local visual information, and if so, what is the nature of this advantage. Perception of movement speed is a visual process that relies on computation of local spatiotemporal signals…

In-situ electrochemical-AFM study of localized corrosion of AlxCoCrFeNi high-entropy alloys in chloride solution

NASA Astrophysics Data System (ADS)

Shi, Yunzhu; Collins, Liam; Balke, Nina; Liaw, Peter K.; Yang, Bin

2018-05-01

In-situ electrochemical (EC)-AFM is employed to investigate the localized corrosion of the AlxCoCrFeNi high-entropy alloys (HEAs). Surface topography changes on the micro/sub-micro scale are monitored at different applied anodizing potentials in a 3.5 wt% NaCl solution. The microstructural evolutions with the increased Al content in the alloys are characterized by SEM, TEM, EDS and EBSD. The results show that by increasing the Al content, the microstructure changes from single solid-solution to multi-phases, leading to the segregations of elements. Due to the microstructural variations in the AlxCoCrFeNi HEAs, localized corrosion processes in different ways after the breakdown of the passive film, which changes from pitting to phase boundary corrosion. The XPS results indicate that an increased Al content in the alloys/phases corresponds to a decreased corrosion resistance of the surface passive film.

Evaluating the Relationship between Equilibrium Passive ...

EPA Pesticide Factsheets

This Critcal Review evaluates passive sampler uptake of hydrophobic organic contaminants (HOCs) in water column and interstitial water exposures as a surrogate for organism bioaccumulation. Fifty-seven studies were found where both passive sampler uptake and organism bioaccumulation were measured and 19 of these investigations provided direct comparisons relating passive sampler uptake and organism bioaccumulation. Polymers compared included low-density polyethylene (LDPE), polyoxymethylene (POM), and polydimethylsiloxane (PDMS), and organisms ranged from polychaetes and oligochaetes to bivalves, aquatic insects, and gastropods. Regression equations correlating bioaccumulation (CL) and passive sampler uptake (CPS) were used to assess the strength of observed relationships. Passive sampling based concentrations resulted in log–log predictive relationships, most of which were within one to 2 orders of magnitude of measured bioaccumulation. Mean coefficients of determination (r2) for LDPE, PDMS, and POM were 0.68, 0.76, and 0.58, respectively. For the available raw, untransformed data, the mean ratio of CL and CPS was 10.8 ± 18.4 (n = 609). Using passive sampling as a surrogate for organism bioaccumulation is viable when biomonitoring organisms are not available. Passive sampling based estimates of bioaccumulation provide useful information for making informed decisions about the bioavailability of HOCs. This review evaluates passive sampler uptake of hydrophobi

Passive and semi-active heave compensator: Project design methodology and control strategies.

PubMed

Cuellar Sanchez, William Humberto; Linhares, Tássio Melo; Neto, André Benine; Fortaleza, Eugênio Libório Feitosa

2017-01-01

Heave compensator is a system that mitigates transmission of heave movement from vessels to the equipment in the vessel. In drilling industry, a heave compensator enables drilling in offshore environments. Heave compensator attenuates movement transmitted from the vessel to the drill string and drill bit ensuring security and efficiency of the offshore drilling process. Common types of heave compensators are passive, active and semi-active compensators. This article presents 4 main points. First, a bulk modulus analysis obtains a simple condition to determine if the bulk modulus can be neglected in the design of hydropneumatic passive heave compensator. Second, the methodology to design passive heave compensators with the desired frequency response. Third, four control methodologies for semi-active heave compensator are tested and compared numerically. Lastly, we show experimental results obtained from a prototype with the methodology developed to design passive heave compensator.

Interior design for passive solar homes

NASA Astrophysics Data System (ADS)

Breen, J. C.

1981-07-01

The increasing emphasis on refinement of passive solar systems brought recognition to interior design as an integral part of passive solar architecture. Interior design can be used as a finetuning tool minimizing many of the problems associated with passive solar energy use in residential buildings. In addition, treatment of interior space in solar model homes may be a prime factor in determining sales success. A new style of interior design is evolving in response to changes in building from incorporating passive solar design features. The psychology behind passive solar architecture is reflected in interiors, and selection of interior components increasingly depends on the functional suitably of various interior elements.

Mesoscale Elucidation of Surface Passivation in the Li–Sulfur Battery Cathode

DOE PAGES

Liu, Zhixiao; Mukherjee, Partha P.

2017-01-23

We report the cathode surface passivation caused by Li 2S precipitation adversely affects the performance of lithium-sulfur (Li-S) batteries. Li 2S precipitation is a complicated mesoscale process involving adsorption, desorption and diffusion kinetics, which are affected profoundly by the reactant concentration and operating temperature. In this work, a mesoscale interfacial model is presented to study the growth of Li 2S film on carbon cathode surface. Li 2S film growth experiences nucleation, isolated Li 2S island growth and island coalescence. The slow adsorption rate at small S 2- concentration inhibits the formation of nucleation seeds and the lateral growth of Limore » 2S islands, which deters surface passivation. An appropriate operating temperature, especially in the medium-to-high temperature range, can also defer surface passivation. Fewer Li 2S nucleation seeds form in such an operating temperature range, which facilitates heterogeneous growth and thereby inhibits the lateral growth of the Li 2S film, which may also result in reduced surface passivation. Finally, the high specific surface area of the cathode microstructure is expected to mitigate the surface passivation.« less

Atypical Local Interference Affects Global Processing in Children with Neurofibromatosis Type 1.

PubMed

Payne, Jonathan M; Porter, Melanie A; Bzishvili, Samantha; North, Kathryn N

2017-05-01

To examine hierarchical visuospatial processing in children with neurofibromatosis type 1 (NF1), a single gene disorder associated with visuospatial impairments, attention deficits, and executive dysfunction. We used a modified Navon paradigm consisting of a large "global" shape composed of smaller "local" shapes that were either congruent (same) or incongruent (different) to the global shape. Participants were instructed to name either the global or local shape within a block. Reaction times, interference ratios, and error rates of children with NF1 (n=30) and typically developing controls (n=24) were compared. Typically developing participants demonstrated the expected global processing bias evidenced by a vulnerability to global interference when naming local stimuli without a cost of congruence when naming global stimuli. NF1 participants, however, experienced significant interference from the unattended level when naming both local and global levels of the stimuli. Findings suggest that children with NF1 do not demonstrate the typical human bias of processing visual information from a global perspective. (JINS, 2017, 23, 446-450).

Proceedings of the technical exchange meeting on passive radon monnitoring

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

Duray, J.R.; Langner, H. Jr.; Martz, D.E.

1987-09-01

The purpose of the meeting was to bring together a number of scientists active in the development and use of passive radon monitoring instrumentation, primarily activated charcoal detectors and alpha track detectors. Many of those present expressed a desire to receive copies of the viewgraphs and other materials presented. Most have supplied extended abstracts or complete reports. These materials are reproduced here as a Technical Measurements Center Report for the benefit of those attending the meeting and for others interested in passive radon monitoring. Individual papers were processed separately for the data base.

Cultural variations in global versus local processing: a developmental perspective.

PubMed

Oishi, Shigehiro; Jaswal, Vikram K; Lillard, Angeline S; Mizokawa, Ai; Hitokoto, Hidefumi; Tsutsui, Yoshiro

2014-12-01

We conducted 3 studies to explore cultural differences in global versus local processing and their developmental trajectories. In Study 1 (N = 363), we found that Japanese college students were less globally oriented in their processing than American or Argentine participants. We replicated this effect in Study 2 (N = 1,843) using a nationally representative sample of Japanese and American adults ages 20 to 69, and found further that adults in both cultures became more globally oriented with age. In Study 3 (N = 133), we investigated the developmental course of the cultural difference using Japanese and American children, and found it was evident by 4 years of age. Cultural variations in global versus local processing emerge by early childhood, and remain throughout adulthood. At the same time, both Japanese and Americans become increasingly global processors with age. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Comprehensive analytical model for locally contacted rear surface passivated solar cells

NASA Astrophysics Data System (ADS)

Wolf, Andreas; Biro, Daniel; Nekarda, Jan; Stumpp, Stefan; Kimmerle, Achim; Mack, Sebastian; Preu, Ralf

2010-12-01

For optimum performance of solar cells featuring a locally contacted rear surface, the metallization fraction as well as the size and distribution of the local contacts are crucial, since Ohmic and recombination losses have to be balanced. In this work we present a set of equations which enable to calculate this trade off without the need of numerical simulations. Our model combines established analytical and empirical equations to predict the energy conversion efficiency of a locally contacted device. For experimental verification, we fabricate devices from float zone silicon wafers of different resistivity using the laser fired contact technology for forming the local rear contacts. The detailed characterization of test structures enables the determination of important physical parameters, such as the surface recombination velocity at the contacted area and the spreading resistance of the contacts. Our analytical model reproduces the experimental results very well and correctly predicts the optimum contact spacing without the use of free fitting parameters. We use our model to estimate the optimum bulk resistivity for locally contacted devices fabricated from conventional Czochralski-grown silicon material. These calculations use literature values for the stable minority carrier lifetime to account for the bulk recombination caused by the formation of boron-oxygen complexes under carrier injection.

Local Conjecturing Process in the Solving of Pattern Generalization Problem

ERIC Educational Resources Information Center

Sutarto; Nusantara, Toto; Subanji; Sisworo

2016-01-01

This aim of this study is to describe the process of local conjecturing in generalizing patterns based on Action, Process, Object, Schema (APOS) theory. The subjects were 16 grade 8 students from a junior high school. Data collection used Pattern Generalization Problem (PGP) and interviews. In the first stage, students completed PGP; in the second…

Closing the energy gap through passive energy expenditure

USDA-ARS?s Scientific Manuscript database

Development of obesity is a gradual process occurring when daily energy intake persistently exceeds energy expenditure (EE). Typical daily weight gain is attributed to an energy gap or excess of stored energy of 15 to 50 kcal/day. Sedentary jobs likely promote weight gain. Standing may be a passive ...

Enhancement and Passive Acoustic Mapping of Cavitation from Fluorescently Tagged Magnetic Resonance-Visible Magnetic Microbubbles In Vivo.

PubMed

Crake, Calum; Owen, Joshua; Smart, Sean; Coviello, Christian; Coussios, Constantin-C; Carlisle, Robert; Stride, Eleanor

2016-12-01

Previous work has indicated the potential of magnetically functionalized microbubbles to localize and enhance cavitation activity under focused ultrasound exposure in vitro. The aim of this study was to investigate magnetic targeting of microbubbles for promotion of cavitation in vivo. Fluorescently labelled magnetic microbubbles were administered intravenously in a murine xenograft model. Cavitation was induced using a 0.5-MHz focused ultrasound transducer at peak negative focal pressures of 1.2-2.0 MPa and monitored in real-time using B-mode imaging and passive acoustic mapping. Magnetic targeting was found to increase the amplitude of the cavitation signal by approximately 50% compared with untargeted bubbles. Post-exposure magnetic resonance imaging indicated deposition of magnetic nanoparticles in tumours. Magnetic targeting was similarly associated with increased fluorescence intensity in the tumours after the experiments. These results suggest that magnetic targeting could potentially be used to improve delivery of cavitation-mediated therapy and that passive acoustic mapping could be used for real-time monitoring of this process. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Passive Seismic for Hydrocarbon Indicator : Between Expectation and Reality

NASA Astrophysics Data System (ADS)

Pandito, Riky H. B.

2018-03-01

In between 5 – 10 years, in our country, passive seismic method became more popular to finding hydrocarbon. Low price, nondestructive acquisition and easy to mobilization is the best reason for choose the method. But in the other part, some people are pessimistically to deal with the result. Instrument specification, data condition and processing methods is several points which influence characteristic and interpretation passive seismic result. In 2010 one prospect in East Java Basin has been measurement constist of 112 objective points and several calibration points. Data measurement results indicate a positive response. Furthermore, in 2013 exploration drliing conducted on the prospect. Drill steam test showes 22 MMCFD in objective zone, upper – late oligocene. In 2015, remeasurement taken in objective area and show consistent responses with previous measurement. Passive seismic is unique method, sometimes will have difference results on dry, gas and oil area, in field production and also temporary suspend area with hidrocarbon content.

Passive and active floating torque during swimming.

PubMed

Kjendlie, Per-Ludvik; Stallman, Robert Keig; Stray-Gundersen, James

2004-10-01

The purpose of this study was to examine the effect of passive underwater torque on active body angle with the horizontal during front crawl swimming and to assess the effect of body size on passive torque and active body angle. Additionally, the effects of passive torque, body angle and hydrostatic lift on maximal sprinting performance were addressed. Ten boys [aged 11.7 (0.8) years] and 12 male adult [aged 21.4 (3.7) years] swimmers volunteered to participate. Their body angle with the horizontal was measured at maximal velocity, and at two submaximal velocities using an underwater video camera system. Passive torque and hydrostatic lift were measured during an underwater weighing procedure, and the center of mass and center of volume were determined. The results showed that passive torque correlated significantly with the body angle at a velocity 63% of v(max) ( alpha(63) r=-0.57), and that size-normalized passive torque correlated significantly with the alpha(63) and alpha(77) (77% of v(max)) with r=-0.59 and r=-0.54 respectively. Hydrostatic lift correlated with alpha(63) with r=-0.45. The negative correlation coefficients are suggested to be due to the adults having learned to overcome passive torque when swimming at submaximal velocities by correcting their body angle. It is concluded that at higher velocities the passive torque and hydrostatic lift do not influence body angle during swimming. At a velocity of 63% of v(max), hydrostatic lift and passive torque influences body angle. Passive torque and size-normalized passive torque increases with body size. When corrected for body size, hydrostatic lift and passive torque did not influence the maximal sprinting velocity.

Visual Search in ASD: Instructed Versus Spontaneous Local and Global Processing.

PubMed

Van der Hallen, Ruth; Evers, Kris; Boets, Bart; Steyaert, Jean; Noens, Ilse; Wagemans, Johan

2016-09-01

Visual search has been used extensively to investigate differences in mid-level visual processing between individuals with ASD and TD individuals. The current study employed two visual search paradigms with Gaborized stimuli to assess the impact of task distractors (Experiment 1) and task instruction (Experiment 2) on local-global visual processing in ASD versus TD children. Experiment 1 revealed both groups to be equally sensitive to the absence or presence of a distractor, regardless of the type of target or type of distractor. Experiment 2 revealed a differential effect of task instruction for ASD compared to TD, regardless of the type of target. Taken together, these results stress the importance of task factors in the study of local-global visual processing in ASD.

The link between exercise and titin passive stiffness.

PubMed

Lalande, Sophie; Mueller, Patrick J; Chung, Charles S

2017-09-01

What is the topic of this review? This review focuses on how in vivo and molecular measurements of cardiac passive stiffness can predict exercise tolerance and how exercise training can reduce cardiac passive stiffness. What advances does it highlight? This review highlights advances in understanding the relationship between molecular (titin-based) and in vivo (left ventricular) passive stiffness, how passive stiffness modifies exercise tolerance, and how exercise training may be therapeutic for cardiac diseases with increased passive stiffness. Exercise can help alleviate the negative effects of cardiovascular disease and cardiovascular co-morbidities associated with sedentary behaviour; this may be especially true in diseases that are associated with increased left ventricular passive stiffness. In this review, we discuss the inverse relationship between exercise tolerance and cardiac passive stiffness. Passive stiffness is the physical property of cardiac muscle to produce a resistive force when stretched, which, in vivo, is measured using the left ventricular end diastolic pressure-volume relationship or is estimated using echocardiography. The giant elastic protein titin is the major contributor to passive stiffness at physiological muscle (sarcomere) lengths. Passive stiffness can be modified by altering titin isoform size or by post-translational modifications. In both human and animal models, increased left ventricular passive stiffness is associated with reduced exercise tolerance due to impaired diastolic filling, suggesting that increased passive stiffness predicts reduced exercise tolerance. At the same time, exercise training itself may induce both short- and long-term changes in titin-based passive stiffness, suggesting that exercise may be a treatment for diseases associated with increased passive stiffness. Direct modification of passive stiffness to improve exercise tolerance is a potential therapeutic approach. Titin passive stiffness itself may

Directional, passive liquid transport: the Texas horned lizard as a model for a biomimetic 'liquid diode'.

PubMed

Comanns, Philipp; Buchberger, Gerda; Buchsbaum, Andreas; Baumgartner, Richard; Kogler, Alexander; Bauer, Siegfried; Baumgartner, Werner

2015-08-06

Moisture-harvesting lizards such as the Texas horned lizard (Iguanidae: Phrynosoma cornutum) live in arid regions. Special skin adaptations enable them to access water sources such as moist sand and dew: their skin is capable of collecting and transporting water directionally by means of a capillary system between the scales. This fluid transport is passive, i.e. requires no external energy, and directs water preferentially towards the lizard's snout. We show that this phenomenon is based on geometric principles, namely on a periodic pattern of interconnected half-open capillary channels that narrow and widen. Following a biomimetic approach, we used these principles to develop a technical prototype design. Building upon the Young-Laplace equation, we derived a theoretical model for the local behaviour of the liquid in such capillaries. We present a global model for the penetration velocity validated by experimental data. Artificial surfaces designed in accordance with this model prevent liquid flow in one direction while sustaining it in the other. Such passive directional liquid transport could lead to process improvements and reduction of resources in many technical applications. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Role of bond adaptability in the passivation of colloidal quantum dot solids.

PubMed

Thon, Susanna M; Ip, Alexander H; Voznyy, Oleksandr; Levina, Larissa; Kemp, Kyle W; Carey, Graham H; Masala, Silvia; Sargent, Edward H

2013-09-24

Colloidal quantum dot (CQD) solids are attractive materials for photovoltaic devices due to their low-cost solution-phase processing, high absorption cross sections, and their band gap tunability via the quantum size effect. Recent advances in CQD solar cell performance have relied on new surface passivation strategies. Specifically, cadmium cation passivation of surface chalcogen sites in PbS CQDs has been shown to contribute to lowered trap state densities and improved photovoltaic performance. Here we deploy a generalized solution-phase passivation strategy as a means to improving CQD surface management. We connect the effects of the choice of metal cation on solution-phase surface passivation, film-phase trap density of states, minority carrier mobility, and photovoltaic power conversion efficiency. We show that trap passivation and midgap density of states determine photovoltaic device performance and are strongly influenced by the choice of metal cation. Supported by density functional theory simulations, we propose a model for the role of cations, a picture wherein metals offering the shallowest electron affinities and the greatest adaptability in surface bonding configurations eliminate both deep and shallow traps effectively even in submonolayer amounts. This work illustrates the importance of materials choice in designing a flexible passivation strategy for optimum CQD device performance.

Thermal-hydraulic modeling needs for passive reactors

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

Kelly, J.M.

1997-07-01

The U.S. Nuclear Regulatory Commission has received an application for design certification from the Westinghouse Electric Corporation for an Advanced Light Water Reactor design known as the AP600. As part of the design certification process, the USNRC uses its thermal-hydraulic system analysis codes to independently audit the vendor calculations. The focus of this effort has been the small break LOCA transients that rely upon the passive safety features of the design to depressurize the primary system sufficiently so that gravity driven injection can provide a stable source for long term cooling. Of course, large break LOCAs have also been considered,more » but as the involved phenomena do not appear to be appreciably different from those of current plants, they were not discussed in this paper. Although the SBLOCA scenario does not appear to threaten core coolability - indeed, heatup is not even expected to occur - there have been concerns as to the performance of the passive safety systems. For example, the passive systems drive flows with small heads, consequently requiring more precision in the analysis compared to active systems methods for passive plants as compared to current plants with active systems. For the analysis of SBLOCAs and operating transients, the USNRC uses the RELAP5 thermal-hydraulic system analysis code. To assure the applicability of RELAP5 to the analysis of these transients for the AP600 design, a four year long program of code development and assessment has been undertaken.« less

Passive and semi-active heave compensator: Project design methodology and control strategies

PubMed Central

Cuellar Sanchez, William Humberto; Neto, André Benine; Fortaleza, Eugênio Libório Feitosa

2017-01-01

Heave compensator is a system that mitigates transmission of heave movement from vessels to the equipment in the vessel. In drilling industry, a heave compensator enables drilling in offshore environments. Heave compensator attenuates movement transmitted from the vessel to the drill string and drill bit ensuring security and efficiency of the offshore drilling process. Common types of heave compensators are passive, active and semi-active compensators. This article presents 4 main points. First, a bulk modulus analysis obtains a simple condition to determine if the bulk modulus can be neglected in the design of hydropneumatic passive heave compensator. Second, the methodology to design passive heave compensators with the desired frequency response. Third, four control methodologies for semi-active heave compensator are tested and compared numerically. Lastly, we show experimental results obtained from a prototype with the methodology developed to design passive heave compensator. PMID:28813494

The passive-aggressive organization.

PubMed

Kaplan, Robert S; Norton, David P

2005-10-01

Passive-aggressive organizations are friendly places to work: People are congenial, conflict is rare, and consensus is easy to reach. But, at the end of the day, even the best proposals fail to gain traction, and a company can go nowhere so imperturbably that it's easy to pretend everything is fine. Such companies are not necessarily saddled with mulishly passive-aggressive employees. Rather, they are filled with mostly well-intentioned people who are the victirms of flawed processes and policies. Commonly, a growing company's halfhearted or poorly thought-out attempts to decentralize give rise to multiple layers of managers, whose authority for making decisions becomes increasingly unclear. Some managers, as a result, hang back, while others won't own up to the calls they've made, inviting colleagues to second-guess or overturn the decisions. In such organizations, information does not circulate freely, and that makes it difficult for workers to understand the impact of their actions on company performance and for managers to correctly appraise employees' value to the organization. A failure to accurately match incentives to performance stifles initiative, and people do just enough to get by. Breaking free from this pattern is hard; a long history of seeing corporate initiatives ignored and then fade away tends to make people cynical. Often it's best to bring in an outsider to signal that this time things will be different. He or she will need to address every obstacle all at once: clarify decision rights; see to it that decisions stick; and reward people for sharing information and adding value, not for successfully negotiating corporate politics. If those steps are not taken, it's only a matter of time before the diseased elements of a passive-aggressive organization overwhelm the remaining healthy ones and drive the company into financial distress.

Process Dependence of H Passivation and Doping in H-implanted ZnO

DTIC Science & Technology

2013-01-04

Columbus, OH 43210, USA 2 Semiconductor Research Center, Wright State University, Dayton, OH 45432, USA 3 Sensors Directorate, Air Force Research...electrical properties. (Some figures may appear in colour only in the online journal) 1. Introduction The wide band gap semiconductor ZnO (Eg ≈ 3.4 eV) is a...theoretical studies predicted that H is likely to passivate zinc vacancy (VZn) and substitutional lithium on zinc site (LiZn) defects by forming neutral XZn–H

AMISS - Active and passive MIcrowaves for Security and Subsurface imaging

NASA Astrophysics Data System (ADS)

Soldovieri, Francesco; Slob, Evert; Turk, Ahmet Serdar; Crocco, Lorenzo; Catapano, Ilaria; Di Matteo, Francesca

2013-04-01

The FP7-IRSES project AMISS - Active and passive MIcrowaves for Security and Subsurface imaging is based on a well-combined network among research institutions of EU, Associate and Third Countries (National Research Council of Italy - Italy, Technische Universiteit Delft - The Netherlands, Yildiz Technical University - Turkey, Bauman Moscow State Technical University - Russia, Usikov Institute for Radio-physics and Electronics and State Research Centre of Superconductive Radioelectronics "Iceberg" - Ukraine and University of Sao Paulo - Brazil) with the aims of achieving scientific advances in the framework of microwave and millimeter imaging systems and techniques for security and safety social issues. In particular, the involved partners are leaders in the scientific areas of passive and active imaging and are sharing their complementary knowledge to address two main research lines. The first one regards the design, characterization and performance evaluation of new passive and active microwave devices, sensors and measurement set-ups able to mitigate clutter and increase information content. The second line faces the requirements to make State-of-the-Art processing tools compliant with the instrumentations developed in the first line, suitable to work in electromagnetically complex scenarios and able to exploit the unexplored possibilities offered by new instrumentations. The main goals of the project are: 1) Development/improvement and characterization of new sensors and systems for active and passive microwave imaging; 2) Set up, analysis and validation of state of art/novel data processing approach for GPR in critical infrastructure and subsurface imaging; 3) Integration of state of art and novel imaging hardware and characterization approaches to tackle realistic situations in security, safety and subsurface prospecting applications; 4) Development and feasibility study of bio-radar technology (system and data processing) for vital signs detection and

Local active information storage as a tool to understand distributed neural information processing

PubMed Central

Wibral, Michael; Lizier, Joseph T.; Vögler, Sebastian; Priesemann, Viola; Galuske, Ralf

2013-01-01

Every act of information processing can in principle be decomposed into the component operations of information storage, transfer, and modification. Yet, while this is easily done for today's digital computers, the application of these concepts to neural information processing was hampered by the lack of proper mathematical definitions of these operations on information. Recently, definitions were given for the dynamics of these information processing operations on a local scale in space and time in a distributed system, and the specific concept of local active information storage was successfully applied to the analysis and optimization of artificial neural systems. However, no attempt to measure the space-time dynamics of local active information storage in neural data has been made to date. Here we measure local active information storage on a local scale in time and space in voltage sensitive dye imaging data from area 18 of the cat. We show that storage reflects neural properties such as stimulus preferences and surprise upon unexpected stimulus change, and in area 18 reflects the abstract concept of an ongoing stimulus despite the locally random nature of this stimulus. We suggest that LAIS will be a useful quantity to test theories of cortical function, such as predictive coding. PMID:24501593

Passive Sensors for Long Duration Internet of Things Networks.

PubMed

Pereira, Felisberto; Correia, Ricardo; Carvalho, Nuno Borges

2017-10-03

In this work, three different concepts are used to develop a fully passive sensor that is capable of measuring different types of data. The sensor was supplied by Wireless Power Transmission (WPT). Communication between the sensor and reader is established by a backscatter, and to ensure minimum energy consumption, low power techniques are used. In a simplistic way, the process starts by the transmission of two different waves by the reader to the sensor, one of which is used in power transmission and the other of which is used to communicate. Once the sensor is powered, the monitoring process starts. From the monitoring state, results from after processing are used to modulate the incoming wave, which is the information that is sent back from the reader to the tag. This new combination of technologies enables the possibility of using sensors without any cables or batteries to operate 340 cm from the reader. The developed prototype measures acceleration and temperature. However, it is scalable. This system enables a new generation of passive Internet of Things (IoT) devices.

Passive Sensors for Long Duration Internet of Things Networks

PubMed Central

Correia, Ricardo; Carvalho, Nuno Borges

2017-01-01

In this work, three different concepts are used to develop a fully passive sensor that is capable of measuring different types of data. The sensor was supplied by Wireless Power Transmission (WPT). Communication between the sensor and reader is established by a backscatter, and to ensure minimum energy consumption, low power techniques are used. In a simplistic way, the process starts by the transmission of two different waves by the reader to the sensor, one of which is used in power transmission and the other of which is used to communicate. Once the sensor is powered, the monitoring process starts. From the monitoring state, results from after processing are used to modulate the incoming wave, which is the information that is sent back from the reader to the tag. This new combination of technologies enables the possibility of using sensors without any cables or batteries to operate 340 cm from the reader. The developed prototype measures acceleration and temperature. However, it is scalable. This system enables a new generation of passive Internet of Things (IoT) devices. PMID:28972554

Improvement of passive THz camera images

NASA Astrophysics Data System (ADS)

Kowalski, Marcin; Piszczek, Marek; Palka, Norbert; Szustakowski, Mieczyslaw

2012-10-01

Terahertz technology is one of emerging technologies that has a potential to change our life. There are a lot of attractive applications in fields like security, astronomy, biology and medicine. Until recent years, terahertz (THz) waves were an undiscovered, or most importantly, an unexploited area of electromagnetic spectrum. The reasons of this fact were difficulties in generation and detection of THz waves. Recent advances in hardware technology have started to open up the field to new applications such as THz imaging. The THz waves can penetrate through various materials. However, automated processing of THz images can be challenging. The THz frequency band is specially suited for clothes penetration because this radiation does not point any harmful ionizing effects thus it is safe for human beings. Strong technology development in this band have sparked with few interesting devices. Even if the development of THz cameras is an emerging topic, commercially available passive cameras still offer images of poor quality mainly because of its low resolution and low detectors sensitivity. Therefore, THz image processing is very challenging and urgent topic. Digital THz image processing is a really promising and cost-effective way for demanding security and defense applications. In the article we demonstrate the results of image quality enhancement and image fusion of images captured by a commercially available passive THz camera by means of various combined methods. Our research is focused on dangerous objects detection - guns, knives and bombs hidden under some popular types of clothing.

Passivity-based Robust Control of Aerospace Systems

NASA Technical Reports Server (NTRS)

Kelkar, Atul G.; Joshi, Suresh M. (Technical Monitor)

2000-01-01

This report provides a brief summary of the research work performed over the duration of the cooperative research agreement between NASA Langley Research Center and Kansas State University. The cooperative agreement which was originally for the duration the three years was extended by another year through no-cost extension in order to accomplish the goals of the project. The main objective of the research was to develop passivity-based robust control methodology for passive and non-passive aerospace systems. The focus of the first-year's research was limited to the investigation of passivity-based methods for the robust control of Linear Time-Invariant (LTI) single-input single-output (SISO), open-loop stable, minimum-phase non-passive systems. The second year's focus was mainly on extending the passivity-based methodology to a larger class of non-passive LTI systems which includes unstable and nonminimum phase SISO systems. For LTI non-passive systems, five different passification. methods were developed. The primary effort during the years three and four was on the development of passification methodology for MIMO systems, development of methods for checking robustness of passification, and developing synthesis techniques for passifying compensators. For passive LTI systems optimal synthesis procedure was also developed for the design of constant-gain positive real controllers. For nonlinear passive systems, numerical optimization-based technique was developed for the synthesis of constant as well as time-varying gain positive-real controllers. The passivity-based control design methodology developed during the duration of this project was demonstrated by its application to various benchmark examples. These example systems included longitudinal model of an F-18 High Alpha Research Vehicle (HARV) for pitch axis control, NASA's supersonic transport wind tunnel model, ACC benchmark model, 1-D acoustic duct model, piezo-actuated flexible link model, and NASA

The right inferior frontal gyrus processes nested non-local dependencies in music.

PubMed

Cheung, Vincent K M; Meyer, Lars; Friederici, Angela D; Koelsch, Stefan

2018-02-28

Complex auditory sequences known as music have often been described as hierarchically structured. This permits the existence of non-local dependencies, which relate elements of a sequence beyond their temporal sequential order. Previous studies in music have reported differential activity in the inferior frontal gyrus (IFG) when comparing regular and irregular chord-transitions based on theories in Western tonal harmony. However, it is unclear if the observed activity reflects the interpretation of hierarchical structure as the effects are confounded by local irregularity. Using functional magnetic resonance imaging (fMRI), we found that violations to non-local dependencies in nested sequences of three-tone musical motifs in musicians elicited increased activity in the right IFG. This is in contrast to similar studies in language which typically report the left IFG in processing grammatical syntax. Effects of increasing auditory working demands are moreover reflected by distributed activity in frontal and parietal regions. Our study therefore demonstrates the role of the right IFG in processing non-local dependencies in music, and suggests that hierarchical processing in different cognitive domains relies on similar mechanisms that are subserved by domain-selective neuronal subpopulations.

Face Context Influences Local Part Processing: An ERP Study.

PubMed

Zhang, Hong; Sun, Yaoru; Zhao, Lun

2017-09-01

Perception of face parts on the basis of features is thought to be different from perception of whole faces, which is more based on configural information. Face context is also suggested to play an important role in face processing. To investigate how face context influences the early-stage perception of facial local parts, we used an oddball paradigm that tested perceptual stages of face processing rather than recognition. We recorded the event-related potentials (ERPs) elicited by whole faces and face parts presented in four conditions (upright-normal, upright-thatcherised, inverted-normal and inverted-thatcherised), as well as the ERPs elicited by non-face objects (whole houses and house parts) with corresponding conditions. The results showed that face context significantly affected the N170 with increased amplitudes and earlier peak latency for upright normal faces. Removing face context delayed the P1 latency but did not affect the P1 amplitude prominently for both upright and inverted normal faces. Across all conditions, neither the N170 nor the P1 was modulated by house context. The significant changes on the N170 and P1 components revealed that face context influences local part processing at the early stage of face processing and this context effect might be specific for face perception. We further suggested that perceptions of whole faces and face parts are functionally distinguished.

Enhanced Passive Cooling for Waterless-Power Production Technologies

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

Rodriguez, Salvador B.

2016-06-14

Recent advances in the literature and at SNL indicate the strong potential for passive, specialized surfaces to significantly enhance power production output. Our exploratory computational and experimental research indicates that fractal and swirl surfaces can help enable waterless-power production by increasing the amount of heat transfer and turbulence, when compared with conventional surfaces. Small modular reactors, advanced reactors, and non-nuclear plants (e.g., solar and coal) are ideally suited for sCO2 coolant loops. The sCO2 loop converts the thermal heat into electricity, while the specialized surfaces passively and securely reject the waste process heat in an environmentally benign manner. The resultant,more » integrated energy systems are highly suitable for small grids, rural areas, and arid regions.« less

Kinect Posture Reconstruction Based on a Local Mixture of Gaussian Process Models.

PubMed

Liu, Zhiguang; Zhou, Liuyang; Leung, Howard; Shum, Hubert P H

2016-11-01

Depth sensor based 3D human motion estimation hardware such as Kinect has made interactive applications more popular recently. However, it is still challenging to accurately recognize postures from a single depth camera due to the inherently noisy data derived from depth images and self-occluding action performed by the user. In this paper, we propose a new real-time probabilistic framework to enhance the accuracy of live captured postures that belong to one of the action classes in the database. We adopt the Gaussian Process model as a prior to leverage the position data obtained from Kinect and marker-based motion capture system. We also incorporate a temporal consistency term into the optimization framework to constrain the velocity variations between successive frames. To ensure that the reconstructed posture resembles the accurate parts of the observed posture, we embed a set of joint reliability measurements into the optimization framework. A major drawback of Gaussian Process is its cubic learning complexity when dealing with a large database due to the inverse of a covariance matrix. To solve the problem, we propose a new method based on a local mixture of Gaussian Processes, in which Gaussian Processes are defined in local regions of the state space. Due to the significantly decreased sample size in each local Gaussian Process, the learning time is greatly reduced. At the same time, the prediction speed is enhanced as the weighted mean prediction for a given sample is determined by the nearby local models only. Our system also allows incrementally updating a specific local Gaussian Process in real time, which enhances the likelihood of adapting to run-time postures that are different from those in the database. Experimental results demonstrate that our system can generate high quality postures even under severe self-occlusion situations, which is beneficial for real-time applications such as motion-based gaming and sport training.

Citric Acid Alternative to Nitric Acid Passivation

NASA Technical Reports Server (NTRS)

Lewis, Pattie L. (Compiler)

2013-01-01

The Ground Systems Development and Operations GSDO) Program at NASA John F. Kennedy Space Center (KSC) has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described as the launch support and infrastructure modernization program in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of the GSDO Program, the purpose of this project is to demonstratevalidate citric acid as a passivation agent for stainless steel. Successful completion of this project will result in citric acid being qualified for use as an environmentally preferable alternative to nitric acid for passivation of stainless steel alloys in NASA and DoD applications.

An enhanced surface passivation effect in InGaN/GaN disk-in-nanowire light emitting diodes for mitigating Shockley-Read-Hall recombination.

PubMed

Zhao, Chao; Ng, Tien Khee; Prabaswara, Aditya; Conroy, Michele; Jahangir, Shafat; Frost, Thomas; O'Connell, John; Holmes, Justin D; Parbrook, Peter J; Bhattacharya, Pallab; Ooi, Boon S

2015-10-28

We present a detailed study of the effects of dangling bond passivation and the comparison of different sulfide passivation processes on the properties of InGaN/GaN quantum-disk (Qdisk)-in-nanowire based light emitting diodes (NW-LEDs). Our results demonstrated the first organic sulfide passivation process for nitride nanowires (NWs). The results from Raman spectroscopy, photoluminescence (PL) measurements, and X-ray photoelectron spectroscopy (XPS) showed that octadecylthiol (ODT) effectively passivated the surface states, and altered the surface dynamic charge, and thereby recovered the band-edge emission. The effectiveness of the process with passivation duration was also studied. Moreover, we also compared the electro-optical performance of NW-LEDs emitting at green wavelength before and after ODT passivation. We have shown that the Shockley-Read-Hall (SRH) non-radiative recombination of NW-LEDs can be greatly reduced after passivation by ODT, which led to a much faster increasing trend of quantum efficiency and higher peak efficiency. Our results highlighted the possibility of employing this technique to further design and produce high performance NW-LEDs and NW-lasers.

Evaluating the Relationship between Equilibrium Passive ...

EPA Pesticide Factsheets

Objectives. This review evaluates passive sampler uptake of hydrophobic organic contaminants (HOCs) in water column and interstitial water exposures as a surrogate for organism bioaccumulation. Approach/Activities. Fifty-five studies were found where both passive sampler uptake and organism bioaccumulation were measured and 19 of these investigations provided direct comparisons relating passive sampler uptake and organism bioaccumulation. Polymers compared included low density polyethylene (LDPE), polyoxymethylene (POM), and polydimethylsiloxane (PDMS), and organisms ranged from polychaetes and oligochaetes to bivalves, aquatic insects, and gastropods. Regression equations correlating bioaccumulation (CL) and passive sampler uptake (CPS) were used to assess the strength of observed relationships. Results/Lessons Learned. Passive sampling based concentrations resulted in strong logarithmic regression relationships, most of which were within one to two orders of magnitude of measured bioaccumulation. Mean coefficients of determination (r2) for LDPE, PDMS and POM were 0.68, 0.76 and 0.58, respectively. For the available raw data, the mean ratio of CL and CPS was 10.8 ± 18.4 (n = 609). Passive sampler uptake and bioaccumulation were not found to be identical (i.e., CPS ≠ CL) but the logarithmic-based relationships between these values were consistently linear and predictive. This review concludes that in many applications passive sampling may serve as a

Evaluating the Relationship between Equilibrium Passive ...

EPA Pesticide Factsheets

This review evaluates passive sampler uptake of hydrophobic organic contaminants (HOCs) in water column and interstitial water exposures as a surrogate for organism bioaccumulation. Fifty-four studies were found where both passive sampler uptake and organism bioaccumulation were measured and 19 of these investigations provided direct comparisons relating passive sampler uptake and organism bioaccumulation. Polymers compared included low density polyethylene (LDPE), polyoxymethylene (POM), and polydimethylsiloxane (PDMS), and organisms ranged from polychaetes and oligochaetes to bivalves, aquatic insects, and gastropods. Regression equations correlating bioaccumulation (CL) and passive sampler uptake (CPS) were used to assess the strength of observed relationships. Passive sampling based concentrations resulted in logarithmic predictive relationships, most of which were within one to two orders of magnitude of measured bioaccumulation. Mean coefficients of determination (r2) for LDPE, PDMS and POM were 0.68, 0.76 and 0.58, respectively. For the available raw data, the mean ratio of CL and CPS was 10.8 ± 18.4 (n = 609). This review concludes that in many applications passive sampling may serve as a reliable surrogate for biomonitoring organisms when biomonitoring organisms are not available. When applied properly, passive sampling based estimates of bioaccumulation provide useful information for making informed decisions about the bioavailability of HOCs

WiFi-Based Real-Time Calibration-Free Passive Human Motion Detection.

PubMed

Gong, Liangyi; Yang, Wu; Man, Dapeng; Dong, Guozhong; Yu, Miao; Lv, Jiguang

2015-12-21

With the rapid development of WLAN technology, wireless device-free passive human detection becomes a newly-developing technique and holds more potential to worldwide and ubiquitous smart applications. Recently, indoor fine-grained device-free passive human motion detection based on the PHY layer information is rapidly developed. Previous wireless device-free passive human detection systems either rely on deploying specialized systems with dense transmitter-receiver links or elaborate off-line training process, which blocks rapid deployment and weakens system robustness. In the paper, we explore to research a novel fine-grained real-time calibration-free device-free passive human motion via physical layer information, which is independent of indoor scenarios and needs no prior-calibration and normal profile. We investigate sensitivities of amplitude and phase to human motion, and discover that phase feature is more sensitive to human motion, especially to slow human motion. Aiming at lightweight and robust device-free passive human motion detection, we develop two novel and practical schemes: short-term averaged variance ratio (SVR) and long-term averaged variance ratio (LVR). We realize system design with commercial WiFi devices and evaluate it in typical multipath-rich indoor scenarios. As demonstrated in the experiments, our approach can achieve a high detection rate and low false positive rate.

Passivity of the bars manufactured using current technologies: laser-sintering, casting, and milling

NASA Astrophysics Data System (ADS)

Popescu, Diana; Popescu, Sabin; Pop, Daniel; Jivanescu, Anca; Todea, Carmen

2014-01-01

Implant overdentures are often selected as therapeutic options for the treatment of edentulous mandibles. "Passive-fit" between the mesostructures and the implants plays an important role in the longevity of the implant-prosthetic assembly in the oral cavity. "Mis-fit" can cause mechanical or biological complications. The purpose of this test was to investigate the passive adaptation of the bars manufactured through different technologies, and in this respect two bars (short and long) were fabricated by each process: laser-sintering, milling, casting. The tensions induced by tightening the connection screw between the bars and the underlying implants were recorded using strain gauges and used as measuring and comparing tool in testing the bars' "passivity". The results of the test showed that the milled bars had the best "passive-fit", followed by laser-sintered bars, while cast bars had the lowest adaptation level.

Evolution of passive continental margins and initiation of subduction zones

NASA Astrophysics Data System (ADS)

Cloetingh, S. A. P. L.; Wortel, M. J. R.; Vlaar, N. J.

1982-05-01

Although the initiation of subduction is a key element in plate tectonic schemes for evolution of lithospheric plates, the underlying mechanisms are not well understood. Plate rupture is an important aspect of the process of creating a new subduction zone, as stresses of the order of kilobars are required to fracture oceanic lithosphere1. Therefore initiation of subduction could take place preferentially at pre-existing weakness zones or in regions where the lithosphere is prestressed. As such, transform faults2,3 and passive margins4,5 where the lithosphere is downflexed under the influence of sediment loading have been suggested. From a model study of passive margin evolution we found that ageing of passive margins alone does not make them more suitable sites for initiation of subduction. However, extensive sediment loading on young lithosphere might be an effective mechanism for closure of small ocean basins.

Revealing Nanoscale Passivation and Corrosion Mechanisms of Reactive Battery Materials in Gas Environments.

PubMed

Li, Yuzhang; Li, Yanbin; Sun, Yongming; Butz, Benjamin; Yan, Kai; Koh, Ai Leen; Zhao, Jie; Pei, Allen; Cui, Yi

2017-08-09

Lithium (Li) metal is a high-capacity anode material (3860 mAh g -1 ) that can enable high-energy batteries for electric vehicles and grid-storage applications. However, Li metal is highly reactive and repeatedly consumed when exposed to liquid electrolyte (during battery operation) or the ambient environment (throughout battery manufacturing). Studying these corrosion reactions on the nanoscale is especially difficult due to the high chemical reactivity of both Li metal and its surface corrosion films. Here, we directly generate pure Li metal inside an environmental transmission electron microscope (TEM), revealing the nanoscale passivation and corrosion process of Li metal in oxygen (O 2 ), nitrogen (N 2 ), and water vapor (H 2 O). We find that while dry O 2 and N 2 (99.9999 vol %) form uniform passivation layers on Li, trace water vapor (∼1 mol %) disrupts this passivation and forms a porous film on Li metal that allows gas to penetrate and continuously react with Li. To exploit the self-passivating behavior of Li in dry conditions, we introduce a simple dry-N 2 pretreatment of Li metal to form a protective layer of Li nitride prior to battery assembly. The fast ionic conductivity and stable interface of Li nitride results in improved battery performance with dendrite-free cycling and low voltage hysteresis. Our work reveals the detailed process of Li metal passivation/corrosion and demonstrates how this mechanistic insight can guide engineering solutions for Li metal batteries.

10.6% Certified Colloidal Quantum Dot Solar Cells via Solvent-Polarity-Engineered Halide Passivation.

PubMed

Lan, Xinzheng; Voznyy, Oleksandr; García de Arquer, F Pelayo; Liu, Mengxia; Xu, Jixian; Proppe, Andrew H; Walters, Grant; Fan, Fengjia; Tan, Hairen; Liu, Min; Yang, Zhenyu; Hoogland, Sjoerd; Sargent, Edward H

2016-07-13

Colloidal quantum dot (CQD) solar cells are solution-processed photovoltaics with broad spectral absorption tunability. Major advances in their efficiency have been made via improved CQD surface passivation and device architectures with enhanced charge carrier collection. Herein, we demonstrate a new strategy to improve further the passivation of CQDs starting from the solution phase. A cosolvent system is employed to tune the solvent polarity in order to achieve the solvation of methylammonium iodide (MAI) and the dispersion of hydrophobic PbS CQDs simultaneously in a homogeneous phase, otherwise not achieved in a single solvent. This process enables MAI to access the CQDs to confer improved passivation. This, in turn, allows for efficient charge extraction from a thicker photoactive layer device, leading to a certified solar cell power conversion efficiency of 10.6%, a new certified record in CQD photovoltaics.

Electrochemical de-alloying in two dimensions: role of the local atomic environment

NASA Astrophysics Data System (ADS)

Damian, A.; Maroun, F.; Allongue, P.

2016-07-01

We investigate by in situ scanning tunnelling microscopy (STM) the potential dependence of the electrochemical dealloying of NiPd monoatomic layers electrodeposited on Au(111). The dealloying process is achieved by Ni selective dissolution and was studied as a function of NiPd composition: for an alloy with a Ni content >=70%, quasi-complete Ni dissolution is achieved at a potential of -0.9 VMSE whereas for a Ni content <70%, Ni dissolution at the same potential drastically slows down after the removal of small amounts of Ni. The alloy morphology at this ``passivation state'' is characterized by the presence of holes in the alloy monolayer with evidence for the Pd enrichment at the hole edges. These findings are confirmed by Monte Carlo simulations. Further Ni dissolution at passivation was achieved by applying more positive potentials which depend on the alloy composition. These results allowed us to determine the correlation between the Ni dissolution onset potential and the local Pd content.

Study of surface passivation as a function of InP closed-ampoule solar cell fabrication processing variables

NASA Technical Reports Server (NTRS)

Faur, Mircea; Faur, Maria; Jenkins, Phillip; Goradia, Manju; Goradia, Chandra; Bailey, Sheila; Weinberg, Irving; Jayne, Douglas

1990-01-01

The effects of various surface preparation procedures, including chemical treatment and anodic or chemical oxidation, closed-ampoule diffusion conditions, and post-diffusion surface preparation and annealing conditions, on the passivating properties of InP have been investigated in order to optimize the fabrication procedures of n(+)p InP solar cells made by closed-ampoule diffusion of sulfur into p-type InP. The InP substrates used were p-type Cd-doped to a level of 1.7 x 10 to the 16th/cu cm, Zn-doped to levels of 2.2 x 10 to the 16th and 1.2 x 10 to the 18th/cu cm, and n-type S-doped to 4.4 x 10 to the 18th/cu cm. The passivating properties have been evaluated from photoluminescence (PL) and conductance-voltage (G-V) data. Good agreement was found between the level of surface passivation and the composition of different surface layers as revealed by X-ray photoelectron spectroscopy (XPS) analysis.

Electromigration-induced plastic deformation in passivated metal lines

NASA Astrophysics Data System (ADS)

Valek, B. C.; Bravman, J. C.; Tamura, N.; MacDowell, A. A.; Celestre, R. S.; Padmore, H. A.; Spolenak, R.; Brown, W. L.; Batterman, B. W.; Patel, J. R.

2002-11-01

We have used scanning white beam x-ray microdiffraction to study microstructural evolution during an in situ electromigration experiment on a passivated Al(Cu) test line. The data show plastic deformation and grain rotations occurring under the influence of electromigration, seen as broadening, movement, and splitting of reflections diffracted from individual metal grains. We believe this deformation is due to localized shear stresses that arise due to the inhomogeneous transfer of metal along the line. Deviatoric stress measurements show changes in the components of stress within the line, including relaxation of stress when current is removed.

Surface Defect Passivation and Reaction of c-Si in H2S.

PubMed

Liu, Hsiang-Yu; Das, Ujjwal K; Birkmire, Robert W

2017-12-26

A unique passivation process of Si surface dangling bonds through reaction with hydrogen sulfide (H 2 S) is demonstrated in this paper. A high-level passivation quality with an effective minority carrier lifetime (τ eff ) of >2000 μs corresponding to a surface recombination velocity of <3 cm/s is achieved at a temperature range of 550-650 °C. X-ray photoelectron spectroscopy (XPS) confirmed the bonding states of Si and S and provides insights into the reaction pathway of Si with H 2 S and other impurity elements both during and after the reaction. Quantitative analysis of XPS spectra showed that the τ eff increases with an increase in the surface S content up to ∼3.5% and stabilizes thereafter, indicative of surface passivation by monolayer coverage of S on the Si surface. However, S passivation of the Si surface is highly unstable because of thermodynamically favorable reaction with atmospheric H 2 O and O 2 . This instability can be eliminated by capping the S-passivated Si surface with a protective thin film such as low-temperature-deposited amorphous silicon nitride.

Deciphering the influence of the thermal processes on the early passive margins formation

NASA Astrophysics Data System (ADS)

Bousquet, Romain; Nalpas, Thierry; Ballard, Jean-François; Ringenbach, Jean-Claude; Chelalou, Roman; Clerc, Camille

2015-04-01

Many large-scale dynamic processes, from continental rifting to plate subduction, are intimately linked to metamorphic reactions. This close relation between geodynamic processes and metamorphic reactions is, in spite of appearances, yet poorly understood. For example, during extension processes, rocks will be exposed to important temperature, pressures and stress changes. Meanwhile less attention has been paid to other important aspects of the metamorphic processes. When reacting rocks expand and contract, density and volume changes will set up in the surrounding material. While several tectonic models are proposed to explain the formation of extensive basins and passive margins ( simple shear detachment mantle exhumation .... ) a single thermal model (McKenzie , 1978), as a dogma, is used to understanding and modeling the formation and evolution of sedimentary basins . This model is based on the assumption that the extension is only by pure shear and it is instantaneous. Under this approach, the sedimentary deposits occur in two stages. i) A short step , 1 to 10 Ma , controlled by tectonics. ii) A longer step , at least 50 Ma as a result of the thermal evolution of the lithosphere.
However, most stratigraphic data indicate that less thermal model can account for documented vertical movements. The study of the thermal evolution , coupled with other tectonic models , and its consequences have never been studied in detail , although the differences may be significant and it is clear that the petrological changes associated with changes in temperature conditions , influence changes reliefs.
In addition, it seems that the relationship between basin formation and thermal evolution is not always the same:
- Sometimes the temperature rise above 50 to 100 Ma tectonic extension. In the Alps, a significant rise in geothermal gradient Permo -Triassic followed by a "cold" extension , leading to the opening of the Ligurian- Piedmont ocean, from the Middle Jurassic .�

Continental-shelf Scale Passive Ocean AcousticWaveguide Remote Sensing of Marine Mammals and other Submerged Objects including Detection, Localization, and Classification

NASA Astrophysics Data System (ADS)

Wang, Delin

In this thesis, we develop the basics of the Passive Ocean Acoustic Waveguide Remote Sensing (POAWRS) technique for the instantaneous continental-shelf scale detection, localization and species classification of marine mammal vocalizations. POAWRS uses a large-aperture, densely sampled coherent hydrophone array system with orders of magnitude higher array gain to enhance signal-to-noise ratios (SNR) by coherent beamforming, enabling detection of underwater acoustic signals either two orders of magnitude more distant in range or lower in SNR than a single hydrophone. The ability to employ coherent spatial processing of signals with the POAWRS technology significantly improves areal coverage, enabling detection of oceanic sound sources over instantaneous wide areas spanning 100 km or more in diameter. The POAWRS approach was applied to analyze marine mammal vocalizations from diverse species received on a 160-element Office Naval Research Five Octave Research Array (ONR-FORA) deployed during their feeding season in Fall 2006 in the Gulf of Maine. The species-dependent temporal-spatial distribution of marine mammal vocalizations and correlation to the prey fish distributions have been determined. Furthermore, the probability of detection regions, source level distributions and pulse compression gains of the vocalization signals from diverse marine mammal species have been estimated. We also develop an approach for enhancing the angular resolution and improving bearing estimates of acoustic signals received on a coherent hydrophone array with multiple-nested uniformly-spaced subapertures, such as the ONR-FORA, by nonuniform array beamforming. Finally we develop a low-cost non-oil-filled towable prototype hydrophone array that consists of eight hydrophone elements with real-time data acquisition and 100 m tow cable. The approach demonstrated here will be applied in the development of a full 160 element POAWRS-type low-cost coherent hydrophone array system in the future.

The Development of Advanced Passive Acoustic Monitoring Systems Using microMARS Technology

DTIC Science & Technology

2015-09-30

localization that will be available in a number of configurations for deep and shallow water environments alike. OBJECTIVES The project has two...through two test series, first targeting the GPS synchronized shallow water and then the self-synchronized deep water configurations. The project will...main objectives: 1. Development of all the components of a compact passive acoustic monitoring system suitable both for shallow water moored

Passive Sensor Materials Based on Liquid Crystals

DTIC Science & Technology

2011-03-12

REPORT Passive Sensor Materials based on Liquid Crystals 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: Research supported by this grant entitled “Passive...Sensor Materials Based on Liquid Crystals” revolved around an investigation of liquid crystalline materials for use in passive sensors for chemical... based on Liquid Crystals Report Title ABSTRACT Research supported by this grant entitled “Passive Sensor Materials Based on Liquid Crystals” revolved

Passive Imaging in Nondiffuse Acoustic Wavefields

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

Mulargia, Francesco; Castellaro, Silvia

2008-05-30

A main property of diffuse acoustic wavefields is that, taken any two points, each of them can be seen as the source of waves and the other as the recording station. This property is shown to follow simply from array azimuthal selectivity and Huygens principle in a locally isotropic wavefield. Without time reversal, this property holds approximately also in anisotropic azimuthally uniform wavefields, implying much looser constraints for undistorted passive imaging than those required by a diffuse field. A notable example is the seismic noise field, which is generally nondiffuse, but is found to be compatible with a finite aperturemore » anisotropic uniform wavefield. The theoretical predictions were confirmed by an experiment on seismic noise in the mainland of Venice, Italy.« less

Potential Application of a Thermoelectric Generator in Passive Cooling System of Nuclear Power Plants

NASA Astrophysics Data System (ADS)

Wang, Dongqing; Liu, Yu; Jiang, Jin; Pang, Wei; Lau, Woon Ming; Mei, Jun

2017-05-01

In the design of nuclear power plants, various natural circulation passive cooling systems are considered to remove residual heat from the reactor core in the event of a power loss and maintain the plant's safety. These passive systems rely on gravity differences of fluids, resulting from density differentials, rather than using an external power-driven system. Unfortunately, a major drawback of such systems is their weak driving force, which can negatively impact safety. In such systems, there is a temperature difference between the heat source and the heat sink, which potentially offers a natural platform for thermoelectric generator (TEG) applications. While a previous study designed and analyzed a TEG-based passive core cooling system, this paper considers TEG applications in other passive cooling systems of nuclear power plants, after which the concept of a TEG-based passive cooling system is proposed. In such a system, electricity is produced using the system's temperature differences through the TEG, and this electricity is used to further enhance the cooling process.

Spatio-temporal dynamics of processing non-symbolic number: An ERP source localization study

PubMed Central

Hyde, Daniel C.; Spelke, Elizabeth S.

2013-01-01

Coordinated studies with adults, infants, and nonhuman animals provide evidence for two distinct systems of non-verbal number representation. The ‘parallel individuation’ system selects and retains information about 1–3 individual entities and the ‘numerical magnitude’ system establishes representations of the approximate cardinal value of a group. Recent ERP work has demonstrated that these systems reliably evoke functionally and temporally distinct patterns of brain response that correspond to established behavioral signatures. However, relatively little is known about the neural generators of these ERP signatures. To address this question, we targeted known ERP signatures of these systems, by contrasting processing of small versus large non-symbolic numbers, and used a source localization algorithm (LORETA) to identify their cortical origins. Early processing of small numbers, showing the signature effects of parallel individuation on the N1 (∼150 ms), was localized primarily to extrastriate visual regions. In contrast, qualitatively and temporally distinct processing of large numbers, showing the signatures of approximate number representation on the mid-latency P2p (∼200–250 ms), was localized primarily to right intraparietal regions. In comparison, mid-latency small number processing was localized to the right temporal-parietal junction and left-lateralized intraparietal regions. These results add spatial information to the emerging ERP literature documenting the process by which we represent number. Furthermore, these results substantiate recent claims that early attentional processes determine whether a collection of objects will be represented through parallel individuation or as an approximate numerical magnitude by providing evidence that downstream processing diverges to distinct cortical regions. PMID:21830257

Spatiotemporal dynamics of processing nonsymbolic number: an event-related potential source localization study.

PubMed

Hyde, Daniel C; Spelke, Elizabeth S

2012-09-01

Coordinated studies with adults, infants, and nonhuman animals provide evidence for two distinct systems of nonverbal number representation. The "parallel individuation" (PI) system selects and retains information about one to three individual entities and the "numerical magnitude" system establishes representations of the approximate cardinal value of a group. Recent event-related potential (ERP) work has demonstrated that these systems reliably evoke functionally and temporally distinct patterns of brain response that correspond to established behavioral signatures. However, relatively little is known about the neural generators of these ERP signatures. To address this question, we targeted known ERP signatures of these systems, by contrasting processing of small versus large nonsymbolic numbers, and used a source localization algorithm (LORETA) to identify their cortical origins. Early processing of small numbers, showing the signature effects of PI on the N1 (∼150 ms), was localized primarily to extrastriate visual regions. In contrast, qualitatively and temporally distinct processing of large numbers, showing the signatures of approximate number representation on the mid-latency P2p (∼200-250 ms), was localized primarily to right intraparietal regions. In comparison, mid-latency small number processing was localized to the right temporal-parietal junction and left-lateralized intraparietal regions. These results add spatial information to the emerging ERP literature documenting the process by which we represent number. Furthermore, these results substantiate recent claims that early attentional processes determine whether a collection of objects will be represented through PI or as an approximate numerical magnitude by providing evidence that downstream processing diverges to distinct cortical regions. Copyright © 2011 Wiley Periodicals, Inc.

Global/local processing of hierarchical visual stimuli in a conflict-choice task by capuchin monkeys (Sapajus spp.).

PubMed

Truppa, Valentina; Carducci, Paola; De Simone, Diego Antonio; Bisazza, Angelo; De Lillo, Carlo

2017-03-01

In the last two decades, comparative research has addressed the issue of how the global and local levels of structure of visual stimuli are processed by different species, using Navon-type hierarchical figures, i.e. smaller local elements that form larger global configurations. Determining whether or not the variety of procedures adopted to test different species with hierarchical figures are equivalent is of crucial importance to ensure comparability of results. Among non-human species, global/local processing has been extensively studied in tufted capuchin monkeys using matching-to-sample tasks with hierarchical patterns. Local dominance has emerged consistently in these New World primates. In the present study, we assessed capuchins' processing of hierarchical stimuli with a method frequently adopted in studies of global/local processing in non-primate species: the conflict-choice task. Different from the matching-to-sample procedure, this task involved processing local and global information retained in long-term memory. Capuchins were trained to discriminate between consistent hierarchical stimuli (similar global and local shape) and then tested with inconsistent hierarchical stimuli (different global and local shapes). We found that capuchins preferred the hierarchical stimuli featuring the correct local elements rather than those with the correct global configuration. This finding confirms that capuchins' local dominance, typically observed using matching-to-sample procedures, is also expressed as a local preference in the conflict-choice task. Our study adds to the growing body of comparative studies on visual grouping functions by demonstrating that the methods most frequently used in the literature on global/local processing produce analogous results irrespective of extent of the involvement of memory processes.

The Measurement Process in Local Quantum Physics and the EPR Paradox

NASA Astrophysics Data System (ADS)

Doplicher, Sergio

2018-01-01

We describe in a qualitative way a possible picture of the Measurement Process in Quantum Mechanics, which takes into account the finite and non zero time duration T of the interaction between the observed system and the microscopic part of the measurement apparatus; the finite space size R of that apparatus; and the fact that the macroscopic part of the measurement apparatus, having the role of amplifying the effect of that interaction to a macroscopic scale, is composed by a very large but finite number N of particles. The Schrödinger evolution of the composed system can be expected to deform into the conventional picture of the measurement, as an instantaneous action turning a pure state into a mixture, only in the limit {N → ∞, T → 0, R → ∞}. Our main point is to discuss this picture for the measurement of local observables in Quantum Field Theory, where the dynamics of the theory and the measurement itself are described by the same time evolution complying with the Principle of Locality. We comment on the Einstein Podolski Rosen thought experiment, reformulated here only in terms of local observables (rather than global ones, as one particle or polarization observables).The local picture of the measurement process helps to make it clear that there is no conflict with the Principle of Locality.

Screen printed passive components for flexible power electronics

NASA Astrophysics Data System (ADS)

Ostfeld, Aminy E.; Deckman, Igal; Gaikwad, Abhinav M.; Lochner, Claire M.; Arias, Ana C.

2015-10-01

Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive components—inductors, capacitors, and resistors—perform functions such as filtering, short-term energy storage, and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates, and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application.

Screen printed passive components for flexible power electronics

PubMed Central

Ostfeld, Aminy E.; Deckman, Igal; Gaikwad, Abhinav M.; Lochner, Claire M.; Arias, Ana C.

2015-01-01

Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive components—inductors, capacitors, and resistors—perform functions such as filtering, short-term energy storage, and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates, and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application. PMID:26514331

Screen printed passive components for flexible power electronics.

PubMed

Ostfeld, Aminy E; Deckman, Igal; Gaikwad, Abhinav M; Lochner, Claire M; Arias, Ana C

2015-10-30

Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive components-inductors, capacitors, and resistors-perform functions such as filtering, short-term energy storage, and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates, and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application.

Visuomotor learning by passive motor experience

PubMed Central

Sakamoto, Takashi; Kondo, Toshiyuki

2015-01-01

Humans can adapt to unfamiliar dynamic and/or kinematic transformations through the active motor experience. Recent studies of neurorehabilitation using robots or brain-computer interface (BCI) technology suggest that passive motor experience would play a measurable role in motor recovery, however our knowledge of passive motor learning is limited. To clarify the effects of passive motor experience on human motor learning, we performed arm reaching experiments guided by a robotic manipulandum. The results showed that the passive motor experience had an anterograde transfer effect on the subsequent motor execution, whereas no retrograde interference was confirmed in the ABA paradigm experiment. This suggests that the passive experience of the error between visual and proprioceptive sensations leads to the limited but actual compensation of behavior, although it is fragile and cannot be consolidated as a persistent motor memory. PMID:26029091

Crustal geometry of the northeastern Gulf of Aden passive margin: localization of the deformation inferred from receiver function analysis

NASA Astrophysics Data System (ADS)

Tiberi, C.; Leroy, S.; d'Acremont, E.; Bellahsen, N.; Ebinger, C.; Al-Lazki, A.; Pointu, A.

2007-03-01

Here we use receiver function analysis to retrieve crustal thickness and crustal composition along the 35-My-old passive margin of the eastern Gulf of Aden. Our aims are to use results from the 3-D seismic array to map crustal stretching across and along the Aden margin in southern Oman. The array recorded local and teleseismic events between 2003 March and 2004 March. Seventy-eight events were used in our joint inversions for Vp/Vs ratio and depth. The major results are: (1) Crustal thickness decreases from the uplifted rift flank of the margin towards the Sheba mid-ocean ridge. We found a crustal thickness of about 35 km beneath the northern rift flank. This value decreases sharply to 26 km beneath the post-rift subsidence zone on the Salalah coastal plain. This 10 km of crustal thinning occurs across a horizontal distance of less than 30 km showing a localization of the crustal thinning below the first known rifted block of the margin. (2) A second rift margin transect located about 50 km to the east shows no thinning from the coast to 50 km onshore. The lack of crustal thickness variation indicates that the maximum crustal stretching could be restricted to offshore regions. (3) The along-strike variations in crustal structure demonstrate the scale and longevity of the regular along-axis rift segmentation. (4) Extension is still observed north of the rifted domain, 70 km onshore from the coast, making the width of margin larger than first expected from geology. (5) The crust has a felsic to normal composition with a probably strong effect of the sedimentary layer on the Vp/Vs ratio (comprised between 1.67 and 1.91).

Frequency and time resolved measurements at rotating ring-disk electrodes for studying localized corrosion

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

Huet, F.; Keddam, M.; Takenouti, H.

1993-07-01

By conferring frequency and time resolution on the rotating rink-disk electrode technique, original information can be obtained on the mechanism of corrosion processes involving the formation of intermediate, passive, or corrosion product layers. The methodology that allows the measurement of the actual flux of chemical species generated by a localized corrosion site is described which takes into account the usual parameters of the RRDE and the location of the active spot on the disk surface. Application to pitting corrosion of iron by Cl[sup [minus

Damage localization by statistical evaluation of signal-processed mode shapes

NASA Astrophysics Data System (ADS)

Ulriksen, M. D.; Damkilde, L.

2015-07-01

Due to their inherent, ability to provide structural information on a local level, mode shapes and t.lieir derivatives are utilized extensively for structural damage identification. Typically, more or less advanced mathematical methods are implemented to identify damage-induced discontinuities in the spatial mode shape signals, hereby potentially facilitating damage detection and/or localization. However, by being based on distinguishing damage-induced discontinuities from other signal irregularities, an intrinsic deficiency in these methods is the high sensitivity towards measurement, noise. The present, article introduces a damage localization method which, compared to the conventional mode shape-based methods, has greatly enhanced robustness towards measurement, noise. The method is based on signal processing of spatial mode shapes by means of continuous wavelet, transformation (CWT) and subsequent, application of a generalized discrete Teager-Kaiser energy operator (GDTKEO) to identify damage-induced mode shape discontinuities. In order to evaluate whether the identified discontinuities are in fact, damage-induced, outlier analysis of principal components of the signal-processed mode shapes is conducted on the basis of T2-statistics. The proposed method is demonstrated in the context, of analytical work with a free-vibrating Euler-Bernoulli beam under noisy conditions.

Local Composite Quantile Regression Smoothing for Harris Recurrent Markov Processes

PubMed Central

Li, Degui; Li, Runze

2016-01-01

In this paper, we study the local polynomial composite quantile regression (CQR) smoothing method for the nonlinear and nonparametric models under the Harris recurrent Markov chain framework. The local polynomial CQR regression method is a robust alternative to the widely-used local polynomial method, and has been well studied in stationary time series. In this paper, we relax the stationarity restriction on the model, and allow that the regressors are generated by a general Harris recurrent Markov process which includes both the stationary (positive recurrent) and nonstationary (null recurrent) cases. Under some mild conditions, we establish the asymptotic theory for the proposed local polynomial CQR estimator of the mean regression function, and show that the convergence rate for the estimator in nonstationary case is slower than that in stationary case. Furthermore, a weighted type local polynomial CQR estimator is provided to improve the estimation efficiency, and a data-driven bandwidth selection is introduced to choose the optimal bandwidth involved in the nonparametric estimators. Finally, we give some numerical studies to examine the finite sample performance of the developed methodology and theory. PMID:27667894

Climate-Specific Passive Building Standards

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

Wright, Graham S.; Klingenberg, Katrin

2015-07-29

In 2012, the U.S. Department of Energy (DOE) recognized the value of performance-based passive building standards when it joined with Passive House Institute US (PHIUS) to promote DOE’s Challenge Home program in tandem with the PHIUS+ Certification program. Since then, the number of passive building projects that have been certified under the partnership has grown exponentially because of some synergy. Passive building represents a well-developed approach to arrive at the envelope basis for zero energy and energy-positive projects by employing performance-based criteria and maximizing cost-effective savings from conservation before implementing renewable energy technologies. The Challenge Home program evolved into themore » Zero Energy Ready Home (ZERH) program in a move toward 1) attaining zero energy and 2) including active renewable energy generation such as photovoltaics (PV)—toward the zero energy goal.« less

Impairment in local and global processing and set-shifting in body dysmorphic disorder

PubMed Central

Kerwin, Lauren; Hovav, Sarit; Helleman, Gerhard; Feusner, Jamie D.

2014-01-01

Body dysmorphic disorder (BDD) is characterized by distressing and often debilitating preoccupations with misperceived defects in appearance. Research suggests that aberrant visual processing may contribute to these misperceptions. This study used two tasks to probe global and local visual processing as well as set shifting in individuals with BDD. Eighteen unmedicated individuals with BDD and 17 non-clinical controls completed two global-local tasks. The embedded figures task requires participants to determine which of three complex figures contained a simpler figure embedded within it. The Navon task utilizes incongruent stimuli comprised of a large letter (global level) made up of smaller letters (local level). The outcome measures were response time and accuracy rate. On the embedded figures task, BDD individuals were slower and less accurate than controls. On the Navon task, BDD individuals processed both global and local stimuli slower and less accurately than controls, and there was a further decrement in performance when shifting attention between the different levels of stimuli. Worse insight correlated with poorer performance on both tasks. Taken together, these results suggest abnormal global and local processing for non-appearance related stimuli among BDD individuals, in addition to evidence of poor set-shifting abilities. Moreover, these abnormalities appear to relate to the important clinical variable of poor insight. Further research is needed to explore these abnormalities and elucidate their possible role in the development and/or persistence of BDD symptoms. PMID:24972487

Local and global processing of music in high-functioning persons with autism: beyond central coherence?

PubMed

Mottron, L; Peretz, I; Ménard, E

2000-11-01

A multi-modal abnormality in the integration of parts and whole has been proposed to account for a bias toward local stimuli in individuals with autism (Frith, 1989; Mottron & Belleville, 1993). In the current experiment, we examined the utility of hierarchical models in characterising musical information processing in autistic individuals. Participants were 13 high-functioning individuals with autism and 13 individuals of normal intelligence matched on chronological age, nonverbal IQ, and laterality, and without musical experience. The task consisted of same-different judgements of pairs of melodies. Differential local and global processing was assessed by manipulating the level, local or global, at which modifications occurred. No deficit was found in the two measures of global processing. In contrast, the clinical group performed better than the comparison group in the detection of change in nontransposed, contour-preserved melodies that tap local processing. These findings confirm the existence of a "local bias" in music perception in individuals with autism, but challenge the notion that it is accounted for by a deficit in global music processing. The present study suggests that enhanced processing of elementary physical properties of incoming stimuli, as found previously in the visual modality, may also exist in the auditory modality.

Low-Temperature Process for Atomic Layer Chemical Vapor Deposition of an Al2O3 Passivation Layer for Organic Photovoltaic Cells.

PubMed

Kim, Hoonbae; Lee, Jihye; Sohn, Sunyoung; Jung, Donggeun

2016-05-01

Flexible organic photovoltaic (OPV) cells have drawn extensive attention due to their light weight, cost efficiency, portability, and so on. However, OPV cells degrade quickly due to organic damage by water vapor or oxygen penetration when the devices are driven in the atmosphere without a passivation layer. In order to prevent damage due to water vapor or oxygen permeation into the devices, passivation layers have been introduced through methods such as sputtering, plasma enhanced chemical vapor deposition, and atomic layer chemical vapor deposition (ALCVD). In this work, the structural and chemical properties of Al2O3 films, deposited via ALCVD at relatively low temperatures of 109 degrees C, 200 degrees C, and 300 degrees C, are analyzed. In our experiment, trimethylaluminum (TMA) and H2O were used as precursors for Al2O3 film deposition via ALCVD. All of the Al2O3 films showed very smooth, featureless surfaces without notable defects. However, we found that the plastic flexible substrate of an OPV device passivated with 300 degrees C deposition temperature was partially bended and melted, indicating that passivation layers for OPV cells on plastic flexible substrates need to be formed at temperatures lower than 300 degrees C. The OPV cells on plastic flexible substrates were passivated by the Al2O3 film deposited at the temperature of 109 degrees C. Thereafter, the photovoltaic properties of passivated OPV cells were investigated as a function of exposure time under the atmosphere.

Method for Biochar Passivation Using Low Percent Oxygen

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

Smith, Kristin; Dupuis, Dan; Wilcox, Esther

2016-06-06

The thermochemical process development unit may be configured for pyrolysis or gasification. The pyrolysis unit operations include: feed transport system; entrained flow reactor; solids removal and collection; and liquid scrubbing, collection, and filtration. Char accumulates in the collection drums at a rate of ~1.5 kg/hr and must be passivated before it is stored or transported.

Highly reliable photosensitive organic-inorganic hybrid passivation layers for a-InGaZnO thin-film transistors

NASA Astrophysics Data System (ADS)

Bermundo, Juan Paolo; Ishikawa, Yasuaki; Yamazaki, Haruka; Nonaka, Toshiaki; Fujii, Mami N.; Uraoka, Yukiharu

2015-07-01

We report the fabrication of a photosensitive hybrid passivation material on amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) that greatly enhance its stability and improve its electrical characteristics. The hybrid passivation based on polysilsesquioxane is transparent and fabricated using a simple solution process. Because the passivation is photosensitive, dry etching was never performed during TFT fabrication. TFTs passivated with this material had a small threshold voltage shift of 0.5 V during positive bias stress, 0.5 V during negative bias stress, and -2.5 V during negative bias illumination stress. Furthermore, TFTs passivated by this layer were stable after being subjected to high relative humidity stress — confirming the superb barrier ability of the passivation. Analysis of secondary ion mass spectrometry showed that a large amount of hydrogen, carbon, and fluorine can be found in the channel region. We show that both hydrogen and fluorine reduced oxygen vacancies and that fluorine stabilized weak oxygen and hydroxide bonds. These results demonstrate the large potential of photosensitive hybrid passivation layers as effective passivation materials.

Real-time computer treatment of THz passive device images with the high image quality

NASA Astrophysics Data System (ADS)

Trofimov, Vyacheslav A.; Trofimov, Vladislav V.

2012-06-01

We demonstrate real-time computer code improving significantly the quality of images captured by the passive THz imaging system. The code is not only designed for a THz passive device: it can be applied to any kind of such devices and active THz imaging systems as well. We applied our code for computer processing of images captured by four passive THz imaging devices manufactured by different companies. It should be stressed that computer processing of images produced by different companies requires using the different spatial filters usually. The performance of current version of the computer code is greater than one image per second for a THz image having more than 5000 pixels and 24 bit number representation. Processing of THz single image produces about 20 images simultaneously corresponding to various spatial filters. The computer code allows increasing the number of pixels for processed images without noticeable reduction of image quality. The performance of the computer code can be increased many times using parallel algorithms for processing the image. We develop original spatial filters which allow one to see objects with sizes less than 2 cm. The imagery is produced by passive THz imaging devices which captured the images of objects hidden under opaque clothes. For images with high noise we develop an approach which results in suppression of the noise after using the computer processing and we obtain the good quality image. With the aim of illustrating the efficiency of the developed approach we demonstrate the detection of the liquid explosive, ordinary explosive, knife, pistol, metal plate, CD, ceramics, chocolate and other objects hidden under opaque clothes. The results demonstrate the high efficiency of our approach for the detection of hidden objects and they are a very promising solution for the security problem.

Passive control of rotorcraft high-speed impulsive noise

NASA Astrophysics Data System (ADS)

Szulc, O.; Doerffer, P.; Tejero, F.

2016-10-01

A strong, normal shock wave, terminating a local supersonic area located at the tip of a helicopter blade, not only limits the aerodynamic performance, but also constitutes an origin of the High-Speed Impulsive (HSI) noise. The application of a passive control device (a shallow cavity covered by a perforated plate) just beneath the interaction region weakens the compression level, thus reducing the main source of the HSI noise. The numerical investigation based on the URANS approach and Bohning/Doerffer (BD) transpiration law (SPARC code) confirms a large potential of the new method. Two exemplary implementations, adapted to model helicopter rotors tested at NASA Ames facility in transonic conditions: Caradonna-Tung (lifting, transonic hover) and Caradonna-Laub-Tung (non-lifting, high-speed forward flight), demonstrate the possible gains in terms of the reduction of acoustic pressure fluctuations in the near-field of the blade tip. The CFD results are validated against the experimental data obtained for the reference configurations (no control), while the analysis of the passive control arrangement is based on a purely numerical research. The normal shock wave is effectively eliminated by the wall ventilation exerting a positive impact on the generated level of the HSI noise.

A Passive System Reliability Analysis for a Station Blackout

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

Brunett, Acacia; Bucknor, Matthew; Grabaskas, David

2015-05-03

The latest iterations of advanced reactor designs have included increased reliance on passive safety systems to maintain plant integrity during unplanned sequences. While these systems are advantageous in reducing the reliance on human intervention and availability of power, the phenomenological foundations on which these systems are built require a novel approach to a reliability assessment. Passive systems possess the unique ability to fail functionally without failing physically, a result of their explicit dependency on existing boundary conditions that drive their operating mode and capacity. Argonne National Laboratory is performing ongoing analyses that demonstrate various methodologies for the characterization of passivemore » system reliability within a probabilistic framework. Two reliability analysis techniques are utilized in this work. The first approach, the Reliability Method for Passive Systems, provides a mechanistic technique employing deterministic models and conventional static event trees. The second approach, a simulation-based technique, utilizes discrete dynamic event trees to treat time- dependent phenomena during scenario evolution. For this demonstration analysis, both reliability assessment techniques are used to analyze an extended station blackout in a pool-type sodium fast reactor (SFR) coupled with a reactor cavity cooling system (RCCS). This work demonstrates the entire process of a passive system reliability analysis, including identification of important parameters and failure metrics, treatment of uncertainties and analysis of results.« less

Local infiltration of rabies immunoglobulins without systemic intramuscular administration: An alternative cost effective approach for passive immunization against rabies

PubMed Central

Bharti, Omesh Kumar; Madhusudana, Shampur Narayan; Gaunta, Pyare Lal; Belludi, Ashwin Yajaman

2016-01-01

ABSTRACT Presently the dose of rabies immunoglobulin (RIG) which is an integral part of rabies post exposure prophylaxis (PEP) is calculated based on body weight though the recommendation is to infiltrate the wound(s). This practice demands large quantities of RIG which may be unaffordable to many patients. In this background, we conducted this study to know if the quantity and cost of RIG can be reduced by restricting passive immunization to local infiltration alone and avoiding systemic intramuscular administration based on the available scientific evidence. Two hundred and sixty nine category III patients bitten by suspect or confirmed rabid dogs/animals were infiltrated with equine rabies immunoglobulin (ERIGs) in and around the wound. The quantity of ERIG used was proportionate to the size and number of wounds irrespective of their body weight. They were followed with a regular course of rabies vaccination by intra-dermal route. As against 363 vials of RIGs required for all these cases as per current recommendation based on body weight, they required only 42 vials of 5ml RIG. Minimum dose of RIGs given was 0.25 ml and maximum dose given was 8 ml. On an average 1.26 ml of RIGs was required per patient that costs Rs. 150 ($3). All the patients were followed for 9 months and they were healthy and normal at the end of observation period. With local infiltration, that required small quantities of RIG, the RIGs could be made available to all patients in times of short supply in the market. A total of 30 (11%) serum samples of patients were tested for rabies virus neutralizing antibodies by the rapid fluorescent focus inhibition test (RFFIT) and all showed antibody titers >0.5 IU/mL by day 14. In no case the dose was higher than that required based on body weight and no immunosuppression resulted. To conclude, this pilot study shows that local infiltration of RIG need to be considered in times of non-availability in the market or unaffordability by poor patients

Statistical validation and an empirical model of hydrogen production enhancement found by utilizing passive flow disturbance in the steam-reformation process

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

Erickson, Paul A.; Liao, Chang-hsien

2007-11-15

A passive flow disturbance has been proven to enhance the conversion of fuel in a methanol-steam reformer. This study presents a statistical validation of the experiment based on a standard 2{sup k} factorial experiment design and the resulting empirical model of the enhanced hydrogen producing process. A factorial experiment design was used to statistically analyze the effects and interactions of various input factors in the experiment. Three input factors, including the number of flow disturbers, catalyst size, and reactant flow rate were investigated for their effects on the fuel conversion in the steam-reformation process. Based on the experimental results, anmore » empirical model was developed and further evaluated with an uncertainty analysis and interior point data. (author)« less

Subwavelength atom localization via coherent manipulation of the Raman gain process

NASA Astrophysics Data System (ADS)

Qamar, Sajid; Mehmood, Asad; Qamar, Shahid

2009-03-01

We present a simple scheme of atom localization in a subwavelength domain via manipulation of Raman gain process. We consider a four-level system with a pump and a weak probe field. In addition, we apply a coherent field to control the gain process. The system is similar to the one used by Agarwal and Dasgupta [Phys. Rev. A 70, 023802 (2004)] for the superluminal pulse propagation through Raman gain medium. For atom localization, we consider both pump and control fields to be the standing-wave fields of the cavity. We show that a much precise position of an atom passing through the standing-wave fields can be determined by measuring the gain spectrum of the probe field.

Separating active and passive influences on stomatal control of transpiration.

PubMed

McAdam, Scott A M; Brodribb, Timothy J

2014-04-01

Motivated by studies suggesting that the stomata of ferns and lycophytes do not conform to the standard active abscisic acid (ABA) -mediated stomatal control model, we examined stomatal behavior in a conifer species (Metasequoia glyptostroboides) that is phylogenetically midway between the fern and angiosperm clades. Similar to ferns, daytime stomatal closure in response to moderate water stress seemed to be a passive hydraulic process in M. glyptostroboides immediately alleviated by rehydrating excised shoots. Only after prolonged exposure to more extreme water stress did active ABA-mediated stomatal closure become important, because foliar ABA production was triggered after leaf turgor loss. The influence of foliar ABA on stomatal conductance and stomatal aperture was highly predictable and additive with the passive hydraulic influence. M. glyptostroboides thus occupies a stomatal behavior type intermediate between the passively controlled ferns and the characteristic ABA-dependent stomatal closure described in angiosperm herbs. These results highlight the importance of considering phylogeny as a major determinant of stomatal behavior.

Gaussian process regression for sensor networks under localization uncertainty

USGS Publications Warehouse

Jadaliha, M.; Xu, Yunfei; Choi, Jongeun; Johnson, N.S.; Li, Weiming

2013-01-01

In this paper, we formulate Gaussian process regression with observations under the localization uncertainty due to the resource-constrained sensor networks. In our formulation, effects of observations, measurement noise, localization uncertainty, and prior distributions are all correctly incorporated in the posterior predictive statistics. The analytically intractable posterior predictive statistics are proposed to be approximated by two techniques, viz., Monte Carlo sampling and Laplace's method. Such approximation techniques have been carefully tailored to our problems and their approximation error and complexity are analyzed. Simulation study demonstrates that the proposed approaches perform much better than approaches without considering the localization uncertainty properly. Finally, we have applied the proposed approaches on the experimentally collected real data from a dye concentration field over a section of a river and a temperature field of an outdoor swimming pool to provide proof of concept tests and evaluate the proposed schemes in real situations. In both simulation and experimental results, the proposed methods outperform the quick-and-dirty solutions often used in practice.

Passive magnetic bearing configurations

DOEpatents

Post, Richard F [Walnut Creek, CA

2011-01-25

A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

Lipid-Based Passivation in Nanofluidics

PubMed Central

2012-01-01

Stretching DNA in nanochannels is a useful tool for direct, visual studies of genomic DNA at the single molecule level. To facilitate the study of the interaction of linear DNA with proteins in nanochannels, we have implemented a highly effective passivation scheme based on lipid bilayers. We demonstrate virtually complete long-term passivation of nanochannel surfaces to a range of relevant reagents, including streptavidin-coated quantum dots, RecA proteins, and RecA–DNA complexes. We show that the performance of the lipid bilayer is significantly better than that of standard bovine serum albumin-based passivation. Finally, we show how the passivated devices allow us to monitor single DNA cleavage events during enzymatic degradation by DNase I. We expect that our approach will open up for detailed, systematic studies of a wide range of protein–DNA interactions with high spatial and temporal resolution. PMID:22432814

On the single sweep processing of auditory brainstem responses: click vs. chirp stimulations and active vs. passive electrodes.

PubMed

Corona-Strauss, Farah I; Delb, Wolfgang; Bloching, Marc; Strauss, Daniel J

2008-01-01

We have recently shown that click evoked auditory brainstem responses (ABRs) single sweeps can efficiently be processed by a hybrid novelty detection system. This approach allowed for the objective detection of hearing thresholds in a fraction of time of conventional schemes, making it appropriate for the efficient implementation of newborn hearing screening procedures. It is the objective of this study to evaluate whether this approach might further be improved by different stimulation paradigms and electrode settings. In particular, we evaluate chirp stimulations which compensate the basilar-membrane dispersion and active electrodes which are less sensitive to movements. This is the first study which is directed to a single sweep processing of chirp evoked ABRs. By concentrating on transparent features and a minimum number of adjustable parameters, we present an objective comparison of click vs.chirp stimulations and active vs. passive electrodes in the ultrafast ABR detection. We show that chirp evoked brainstem responses and active electrodes might improve the single sweeps analysis of ABRs.Consequently, we conclude that a single sweep processing of ABRs for the objective determination of hearing thresholds can further be improved by the use of optimized chirp stimulations and active electrodes.

Quality of Life and Toxicity From Passively Scattered and Spot-Scanning Proton Beam Therapy for Localized Prostate Cancer

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

Pugh, Thomas J.; Munsell, Mark F.; Choi, Seungtaek

Purpose: To report quality of life (QOL)/toxicity in men treated with proton beam therapy for localized prostate cancer and to compare outcomes between passively scattered proton therapy (PSPT) and spot-scanning proton therapy (SSPT). Methods and Materials: Men with localized prostate cancer enrolled on a prospective QOL protocol with a minimum of 2 years' follow-up were reviewed. Comparative groups were defined by technique (PSPT vs SSPT). Patients completed Expanded Prostate Cancer Index Composite questionnaires at baseline and every 3-6 months after proton beam therapy. Clinically meaningful differences in QOL were defined as ≥0.5 × baseline standard deviation. The cumulative incidence ofmore » modified Radiation Therapy Oncology Group grade ≥2 gastrointestinal (GI) or genitourinary (GU) toxicity and argon plasma coagulation were determined by the Kaplan-Meier method. Results: A total of 226 men received PSPT, and 65 received SSPT. Both PSPT and SSPT resulted in statistically significant changes in sexual, urinary, and bowel Expanded Prostate Cancer Index Composite summary scores. Only bowel summary, function, and bother resulted in clinically meaningful decrements beyond treatment completion. The decrement in bowel QOL persisted through 24-month follow-up. Cumulative grade ≥2 GU and GI toxicity at 24 months were 13.4% and 9.6%, respectively. There was 1 grade 3 GI toxicity (PSPT group) and no other grade ≥3 GI or GU toxicity. Argon plasma coagulation application was infrequent (PSPT 4.4% vs SSPT 1.5%; P=.21). No statistically significant differences were appreciated between PSPT and SSPT regarding toxicity or QOL. Conclusion: Both PSPT and SSPT confer low rates of grade ≥2 GI or GU toxicity, with preservation of meaningful sexual and urinary QOL at 24 months. A modest, yet clinically meaningful, decrement in bowel QOL was seen throughout follow-up. No toxicity or QOL differences between PSPT and SSPT were identified. Long-term comparative results

Effectiveness of passivation techniques on hydrogen desorption in a tritium environment

NASA Astrophysics Data System (ADS)

Woodall, Steven Michael

2009-11-01

Tritium is a radioactive isotope of hydrogen. It is used as a fuel in fusion reactors, a booster material in nuclear weapons and as a light source in commercial applications. When tritium is used in fusion reactors, and especially when used in the manufacture of nuclear weapons, purity is critical. For U.S. Department of Energy use, tritium is recycled by Savannah River Site in South Carolina and is processed to a minimum purity of 99.5%. For use elsewhere in the country, it must be shipped and stored, while maintaining the highest purity possible. As an isotope of hydrogen it exchanges easily with the most common isotope of hydrogen, protium. Stainless steel bottles are used to transport and store tritium. Protium, present in air, becomes associated in and on the surface of stainless steel during and after the manufacture of the steel. When filled, the tritium within the bottle exchanges with the protium in and on the surface of the stainless steel, slowly contaminating the pure tritium with protium. The stainless steel is therefore passivated to minimize the protium outgrowth of the bottles into the pure tritium. This research is to determine how effective different passivation techniques are in minimizing the contamination of tritium with protium. Additionally, this research will attempt to determine a relationship between surface chemistry of passivated steels and protium contamination of tritium. The conclusions of this research found that passivated bottles by two companies which routinely provide passivated materials to the US Department of Energy provide low levels of protium outgrowth into pure tritium. A bottle passivated with a material to prevent excessive corrosion in a highly corrosive environment, and a clean and polished bottle provided outgrowth rates roughly twice those of the passivated bottles above. Beyond generally high levels of chromium, oxygen, iron and nickel in the passivated bottles, there did not appear to be a strong correlation

Non-chromate Passivation for LHE ZnNi

DTIC Science & Technology

2017-03-01

control of coatings and processes. Development of an alternative methodology that is simple, repeatable, non -destructive, and capable of scanning across...FINAL REPORT Non -chromate Passivation for LHE ZnNi SERDP Project WP-2527 JANUARY 2017 Matt O’Keefe Missouri S&T...valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES COVERED (From

Technical - Economic Research for Passive Buildings

NASA Astrophysics Data System (ADS)

Miniotaite, Ruta

2017-10-01

A newly constructed passive house must save 80 % of heat resources; otherwise it is not a passive house. The heating energy demand of a passive building is less than 15 kWh/m2 per year. However, a passive house is something more than just an energy-saving house. This concept involves sustainable, high-quality, valuable, healthy and durable construction. Features of a passive house: high insulation of envelope components, high-quality windows, good tightness of the building, regenerative ventilation system and elimination of thermal bridges. The Energy Performance of Buildings Directive (EPBD) 61 requires all new public buildings to become near-zero energy buildings by 2019 and will be extended to all new buildings by 2021. This concept involves sustainable, high-quality, valuable, healthy and durable construction. Foundation, walls and roofs are the most essential elements of a house. The type of foundation for a private house is selected considering many factors. The article examines technological and structural solutions for passive buildings foundation, walls and roofs. The technical-economic comparison of the main structures of a passive house revealed that it is cheaper to install an adequately designed concrete slab foundation than to build strip or pile foundation and the floor separately. Timber stud walls are the cheapest wall option for a passive house and 45-51% cheaper compared to other options. The comparison of roofs and ceilings showed that insulation of the ceiling is 25% more efficient than insulation of the roof. The comparison of the main envelope elements efficiency by multiple-criteria evaluation methods showed that it is economically feasible to install concrete slab on ground foundation, stud walls with sheet cladding and a pitched roof with insulated ceiling.

Method for localizing and isolating an errant process step

DOEpatents

Tobin, Jr., Kenneth W.; Karnowski, Thomas P.; Ferrell, Regina K.

2003-01-01

A method for localizing and isolating an errant process includes the steps of retrieving from a defect image database a selection of images each image having image content similar to image content extracted from a query image depicting a defect, each image in the selection having corresponding defect characterization data. A conditional probability distribution of the defect having occurred in a particular process step is derived from the defect characterization data. A process step as a highest probable source of the defect according to the derived conditional probability distribution is then identified. A method for process step defect identification includes the steps of characterizing anomalies in a product, the anomalies detected by an imaging system. A query image of a product defect is then acquired. A particular characterized anomaly is then correlated with the query image. An errant process step is then associated with the correlated image.

Breakdown of local information processing may underlie isoflurane anesthesia effects.

PubMed

Wollstadt, Patricia; Sellers, Kristin K; Rudelt, Lucas; Priesemann, Viola; Hutt, Axel; Fröhlich, Flavio; Wibral, Michael

2017-06-01

The disruption of coupling between brain areas has been suggested as the mechanism underlying loss of consciousness in anesthesia. This hypothesis has been tested previously by measuring the information transfer between brain areas, and by taking reduced information transfer as a proxy for decoupling. Yet, information transfer is a function of the amount of information available in the information source-such that transfer decreases even for unchanged coupling when less source information is available. Therefore, we reconsidered past interpretations of reduced information transfer as a sign of decoupling, and asked whether impaired local information processing leads to a loss of information transfer. An important prediction of this alternative hypothesis is that changes in locally available information (signal entropy) should be at least as pronounced as changes in information transfer. We tested this prediction by recording local field potentials in two ferrets after administration of isoflurane in concentrations of 0.0%, 0.5%, and 1.0%. We found strong decreases in the source entropy under isoflurane in area V1 and the prefrontal cortex (PFC)-as predicted by our alternative hypothesis. The decrease in source entropy was stronger in PFC compared to V1. Information transfer between V1 and PFC was reduced bidirectionally, but with a stronger decrease from PFC to V1. This links the stronger decrease in information transfer to the stronger decrease in source entropy-suggesting reduced source entropy reduces information transfer. This conclusion fits the observation that the synaptic targets of isoflurane are located in local cortical circuits rather than on the synapses formed by interareal axonal projections. Thus, changes in information transfer under isoflurane seem to be a consequence of changes in local processing more than of decoupling between brain areas. We suggest that source entropy changes must be considered whenever interpreting changes in information

Breakdown of local information processing may underlie isoflurane anesthesia effects

PubMed Central

Sellers, Kristin K.; Priesemann, Viola; Hutt, Axel

2017-01-01

The disruption of coupling between brain areas has been suggested as the mechanism underlying loss of consciousness in anesthesia. This hypothesis has been tested previously by measuring the information transfer between brain areas, and by taking reduced information transfer as a proxy for decoupling. Yet, information transfer is a function of the amount of information available in the information source—such that transfer decreases even for unchanged coupling when less source information is available. Therefore, we reconsidered past interpretations of reduced information transfer as a sign of decoupling, and asked whether impaired local information processing leads to a loss of information transfer. An important prediction of this alternative hypothesis is that changes in locally available information (signal entropy) should be at least as pronounced as changes in information transfer. We tested this prediction by recording local field potentials in two ferrets after administration of isoflurane in concentrations of 0.0%, 0.5%, and 1.0%. We found strong decreases in the source entropy under isoflurane in area V1 and the prefrontal cortex (PFC)—as predicted by our alternative hypothesis. The decrease in source entropy was stronger in PFC compared to V1. Information transfer between V1 and PFC was reduced bidirectionally, but with a stronger decrease from PFC to V1. This links the stronger decrease in information transfer to the stronger decrease in source entropy—suggesting reduced source entropy reduces information transfer. This conclusion fits the observation that the synaptic targets of isoflurane are located in local cortical circuits rather than on the synapses formed by interareal axonal projections. Thus, changes in information transfer under isoflurane seem to be a consequence of changes in local processing more than of decoupling between brain areas. We suggest that source entropy changes must be considered whenever interpreting changes in

Inverse Source Data-Processing Strategies for Radio-Frequency Localization in Indoor Environments.

PubMed

Gennarelli, Gianluca; Al Khatib, Obada; Soldovieri, Francesco

2017-10-27

Indoor positioning of mobile devices plays a key role in many aspects of our daily life. These include real-time people tracking and monitoring, activity recognition, emergency detection, navigation, and numerous location based services. Despite many wireless technologies and data-processing algorithms have been developed in recent years, indoor positioning is still a problem subject of intensive research. This paper deals with the active radio-frequency (RF) source localization in indoor scenarios. The localization task is carried out at the physical layer thanks to receiving sensor arrays which are deployed on the border of the surveillance region to record the signal emitted by the source. The localization problem is formulated as an imaging one by taking advantage of the inverse source approach. Different measurement configurations and data-processing/fusion strategies are examined to investigate their effectiveness in terms of localization accuracy under both line-of-sight (LOS) and non-line of sight (NLOS) conditions. Numerical results based on full-wave synthetic data are reported to support the analysis.

Inverse Source Data-Processing Strategies for Radio-Frequency Localization in Indoor Environments

PubMed Central

Gennarelli, Gianluca; Al Khatib, Obada; Soldovieri, Francesco

2017-01-01

Indoor positioning of mobile devices plays a key role in many aspects of our daily life. These include real-time people tracking and monitoring, activity recognition, emergency detection, navigation, and numerous location based services. Despite many wireless technologies and data-processing algorithms have been developed in recent years, indoor positioning is still a problem subject of intensive research. This paper deals with the active radio-frequency (RF) source localization in indoor scenarios. The localization task is carried out at the physical layer thanks to receiving sensor arrays which are deployed on the border of the surveillance region to record the signal emitted by the source. The localization problem is formulated as an imaging one by taking advantage of the inverse source approach. Different measurement configurations and data-processing/fusion strategies are examined to investigate their effectiveness in terms of localization accuracy under both line-of-sight (LOS) and non-line of sight (NLOS) conditions. Numerical results based on full-wave synthetic data are reported to support the analysis. PMID:29077071

On the classification of active and passive seawater intrusion

NASA Astrophysics Data System (ADS)

Werner, A. D.

2017-12-01

Active and passive seawater intrusion (SWI) arise when the freshwater head gradient slopes downwards towards land and the sea, respectively. However, a third category exists (i.e., passive-active SWI), whereby active SWI occurs inland of a mound in piezometric surface, whereas passive SWI occurs on the seaward side of the mound. In this study, numerical modelling is used to characterize the three forms of SWI, including an overview of the transient features of active SWI. While only simple cross-sectional representations of coastal aquifer settings are considered, the analysis provides guidance on some of the key attributes of each SWI class, as an extension to previous SWI research that offers limited differentiation between the various SWI types. Threshold parameter combinations for the onset of each form of SWI are provided, as derived from sharp-interface, steady-state analytical solutions. Dispersive aspects of SWI are then explored using numerical simulation. Important differences between the various forms of SWI include the salinization of the watertable that occurs under active SWI and in the absence of recharge, and the formation of persistent freshwater lenses in aquifers experiencing active SWI but also subject to surface recharge. Attempts to characterize transient active SWI processes, in terms of buoyancy, advective and dispersive processes, using dimensionless ratios that are drawn from previous studies of steady-state SWI, highlight the complex, nonlinear relationships that govern active SWI, even for idealized circumstances.

End-of-Mission Passivation: Successes and Challenges

NASA Technical Reports Server (NTRS)

Johnson, Nicholas; Matney, Mark

2012-01-01

The passivation of spacecraft and launch vehicle orbital stages at end-of-mission has been a principal space debris mitigation measure world-wide since the 1980 s. Space vehicle passivation includes the removal of stored energies, especially those associated with propulsion and electrical power systems. Prior to 2007 the breakup of non-functioning, non-passivated space vehicles was the major source of hazardous debris in Earth orbit. The United Nations and the Inter-Agency Space Debris Coordination Committee have both included passivation in their formal space debris mitigation guidelines. This often simple countermeasure has been adopted by many spacefaring countries and organizations and has undoubtedly prevented numerous major satellite breakups. For some existing space vehicle designs, passivation requires changes in hardware, software, and/or operational procedures. Questions about the permissible degree of passivation for both current and future space vehicles have arisen and are addressed herein. An important element to be considered is the potentially long period in which the space vehicle will remain in orbit, i.e., up to 25 years after mission termination in LEO and for centuries in orbits above LEO. Finally, the issue of passivation of space vehicles which have failed prematurely is addressed.

WiFi-Based Real-Time Calibration-Free Passive Human Motion Detection †

PubMed Central

Gong, Liangyi; Yang, Wu; Man, Dapeng; Dong, Guozhong; Yu, Miao; Lv, Jiguang

2015-01-01

With the rapid development of WLAN technology, wireless device-free passive human detection becomes a newly-developing technique and holds more potential to worldwide and ubiquitous smart applications. Recently, indoor fine-grained device-free passive human motion detection based on the PHY layer information is rapidly developed. Previous wireless device-free passive human detection systems either rely on deploying specialized systems with dense transmitter-receiver links or elaborate off-line training process, which blocks rapid deployment and weakens system robustness. In the paper, we explore to research a novel fine-grained real-time calibration-free device-free passive human motion via physical layer information, which is independent of indoor scenarios and needs no prior-calibration and normal profile. We investigate sensitivities of amplitude and phase to human motion, and discover that phase feature is more sensitive to human motion, especially to slow human motion. Aiming at lightweight and robust device-free passive human motion detection, we develop two novel and practical schemes: short-term averaged variance ratio (SVR) and long-term averaged variance ratio (LVR). We realize system design with commercial WiFi devices and evaluate it in typical multipath-rich indoor scenarios. As demonstrated in the experiments, our approach can achieve a high detection rate and low false positive rate. PMID:26703612

X-Ray Photoelectron Spectroscopy and Ultrahigh Vacuum Contactless Capacitance-Voltage Characterization of Novel Oxide-Free InP Passivation Process Using a Silicon Surface Quantum Well

NASA Astrophysics Data System (ADS)

Takahashi, Hiroshi; Hashizume, Tamotsu; Hasegawa, Hideki

1999-02-01

In order to understand and optimize a novel oxide-free InP passivation process using a silicon surface quantum well, a detailed in situ X-ray photoelectron spectroscopy (XPS) and ultrahigh vacuum (UHV) contactless capacitance-voltage (C-V) study of the interface was carried out. Calculation of quantum levels in the silicon quantum well was performed on the basis of the band lineup of the strained Si3N4/Si/InP interface and the result indicated that the interface should become free of gap states when the silicon layer thickness is below 5 Å. Experimentally, such a delicate Si3N4/Si/InP structure was realized by partial nitridation of a molecular beam epitaxially (MBE) grown pseudomorphic silicon layer using an electron cyclotron resonance (ECR) N2 plasma. The progress of nitridation was investigated in detail by angle-resolved XPS. A newly developed UHV contactless C-V method realized in situ characterization of surface electronic properties of InP at each processing step for passivation. It was found that the interface state density decreased substantially into the 1010 cm-2 eV-1 range by optimizing the nitridation process of the silicon layer. It was concluded that both the surface bond termination and state removal by quantum confinement are responsible for the NSS reduction.

Effect of low thermal budget annealing on surface passivation of silicon by ALD based aluminum oxide films.

PubMed

Vandana; Batra, Neha; Gope, Jhuma; Singh, Rajbir; Panigrahi, Jagannath; Tyagi, Sanjay; Pathi, P; Srivastava, S K; Rauthan, C M S; Singh, P K

2014-10-21

Thermal ALD deposited Al2O3 films on silicon show a marked difference in surface passivation quality as a function of annealing time (using a rapid thermal process). An effective and quality passivation is realized in short anneal duration (∼100 s) in nitrogen ambient which is reflected in the low surface recombination velocity (SRV <10 cm s(-1)). The deduced values are close to the best reported SRV obtained by the high thermal budget process (with annealing time between 10-30 min), conventionally used for improved surface passivation. Both as-deposited and low thermal budget annealed films show the presence of positive fixed charges and this is never been reported in the literature before. The role of field and chemical passivation is investigated in terms of fixed charge and interface defect densities. Further, the importance of the annealing step sequence in the MIS structure fabrication protocol is also investigated from the view point of its effect on the nature of fixed charges.

An Event-Structural Account of Passive Acquisition in Korean

ERIC Educational Resources Information Center

Lee, Kwee-Ock; Lee, Youngjoo

2008-01-01

Some peculiar properties of children's passives have long been observed in various languages such as an asymmetry between actional passives and nonactional passives. These peculiarities have been accounted for under the hypothesis that children's early passives are adjectival, and as such exhibit properties of adjectival passives in adult grammar.…

Modelling of double air-bridged structured inductor implemented by a GaAs integrated passive device manufacturing process

NASA Astrophysics Data System (ADS)

Li, Yang; Yao, Zhao; Zhang, Chun-Wei; Fu, Xiao-Qian; Li, Zhi-Ming; Li, Nian-Qiang; Wang, Cong

2017-05-01

In order to provide excellent performance and show the development of a complicated structure in a module and system, this paper presents a double air-bridge-structured symmetrical differential inductor based on integrated passive device technology. Corresponding to the proposed complicated structure, a new manufacturing process fabricated on a high-resistivity GaAs substrate is described in detail. Frequency-independent physical models are presented with lump elements and the results of skin effect-based measurements. Finally, some key features of the inductor are compared; good agreement between the measurements and modeled circuit fully verifies the validity of the proposed modeling approach. Meanwhile, we also present a comparison of different coil turns for inductor performance. The proposed work can provide a good solution for the design, fabrication, modeling, and practical application of radio-frequency modules and systems.

Passive gas-gap heat switch for adiabatic demagnetization refrigerator

NASA Technical Reports Server (NTRS)

Shirron, Peter J. (Inventor); Di Pirro, Michael J. (Inventor)

2005-01-01

A passive gas-gap heat switch for use with a multi-stage continuous adiabatic demagnetization refrigerator (ADR). The passive gas-gap heat switch turns on automatically when the temperature of either side of the switch rises above a threshold value and turns off when the temperature on either side of the switch falls below this threshold value. One of the heat switches in this multistage process must be conductive in the 0.25? K to 0.3? K range. All of the heat switches must be capable of switching off in a short period of time (1-2 minutes), and when off to have a very low thermal conductance. This arrangement allows cyclic cooling cycles to be used without the need for separate heat switch controls.

Enlightened Use of Passive Voice in Technical Writing

NASA Technical Reports Server (NTRS)

Trammell, M. K.

1981-01-01

The passive voice as a normal, acceptable, and established syntactic form in technical writing is defended. Passive/active verb ratios, taken from sources including 'antipassivist' text books, are considered. The suitability of the passive voice in technical writing which involves unknown or irrelevant agents is explored. Three 'myths' that the passive (1) utilizes an abnormal and artificial word order, (2) is lifeless, and (3) is indirect are considered. Awkward and abnormal sounding examples encountered in text books are addressed in terms of original context. Unattractive or incoherent passive sentences are explained in terms of inappropriate conversion from active sentences having (1) short nominal or pronominal subjects or (2) verbs with restrictions on their passive use.

Asymptotic Stability of Interconnected Passive Non-Linear Systems

NASA Technical Reports Server (NTRS)

Isidori, A.; Joshi, S. M.; Kelkar, A. G.

1999-01-01

This paper addresses the problem of stabilization of a class of internally passive non-linear time-invariant dynamic systems. A class of non-linear marginally strictly passive (MSP) systems is defined, which is less restrictive than input-strictly passive systems. It is shown that the interconnection of a non-linear passive system and a non-linear MSP system is globally asymptotically stable. The result generalizes and weakens the conditions of the passivity theorem, which requires one of the systems to be input-strictly passive. In the case of linear time-invariant systems, it is shown that the MSP property is equivalent to the marginally strictly positive real (MSPR) property, which is much simpler to check.

26 CFR 1.469-2 - Passive activity loss.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 6 2011-04-01 2011-04-01 false Passive activity loss. 1.469-2 Section 1.469-2...) INCOME TAXES (CONTINUED) Taxable Year for Which Deductions Taken § 1.469-2 Passive activity loss. (a)-(c... passive activity unless the interest in property was used in a passive activity for either— (1) 20 percent...

Passive Acoustic Methods for Tracking Marine Mammals Using Widely-Spaced Bottom-Mounted Hydrophones

DTIC Science & Technology

2011-10-26

standard time-of-arrival (TOA) tracking methods fail. Clicks and long duration calls (whistles or baleen whale calls) were both considered. Methods...Evaluation Center (AUTEC) and the Pacific Missile Range Facility (PMRF). Beaked whales , minke whales , humpback whales , and sperm whales were the main species...of interest. io. auBJEUi i Lmvia Passive acoustic monitoring, localization, tracking, minke whale , beaked whale , sperm whale , humpback whale

Passive Acoustic Mapping with the Angular Spectrum Method

PubMed Central

Crake, Calum; McDannold, Nathan; Clement, Gregory T.

2017-01-01

In the present proof of principle study, we evaluated the homogenous angular spectrum method for passive acoustic mapping (AS-PAM) of microbubble oscillations using simulated and experimental data. In the simulated data we assessed the ability of AS-PAM to form 3D maps of a single and multiple point sources. Then, in the two dimensional limit, we compared the 2D maps from AS-PAM with alternative frequency and time domain passive acoustic mapping (FD- and TD-PAM) approaches. Finally, we assessed the ability of AS-PAM to visualize microbubble activity in vivo with data obtained during 8 different experiments of FUS-induced blood-brain barrier disruption in 3 nonhuman primates, using a clinical MR-guided FUS system. Our in silico results demonstrate AS-PAM can be used to perform 3D passive acoustic mapping. 2D AS-PAM as compared to FD- PAM and TD-PAM is 10 and 200 times faster respectively and has similar sensitivity, resolution, and localization accuracy, even when the noise was 10-fold higher than the signal. In-vivo, the AS-PAM reconstructions of emissions at frequency bands pertinent to the different types of microbubble oscillations were also found to be more sensitive than TD-PAM. AS-PAM of harmonic-only components predicted safe blood-brain barrier disruption, whereas AS-PAM of broadband emissions correctly identified MR-evident tissue damage. The disparity (3.2mm) in the location of the cavitation activity between the three methods was within their resolution limits. These data clearly demonstrate that AS-PAM is a sensitive and fast approach for PAM, thus providing a clinically relevant method to guide therapeutic ultrasound procedures. PMID:28026755

Systems Factorial Technology provides new insights on global-local information processing in autism spectrum disorders.

PubMed

Johnson, Shannon A; Blaha, Leslie M; Houpt, Joseph W; Townsend, James T

2010-02-01

Previous studies of global-local processing in autism spectrum disorders (ASDs) have indicated mixed findings, with some evidence of a local processing bias, or preference for detail-level information, and other results suggesting typical global advantage, or preference for the whole or gestalt. Findings resulting from this paradigm have been used to argue for or against a detail focused processing bias in ASDs, and thus have important theoretical implications. We applied Systems Factorial Technology, and the associated Double Factorial Paradigm (both defined in the text), to examine information processing characteristics during a divided attention global-local task in high-functioning individuals with an ASD and typically developing controls. Group data revealed global advantage for both groups, contrary to some current theories of ASDs. Information processing models applied to each participant revealed that task performance, although showing no differences at the group level, was supported by different cognitive mechanisms in ASD participants compared to controls. All control participants demonstrated inhibitory parallel processing and the majority demonstrated a minimum-time stopping rule. In contrast, ASD participants showed exhaustive parallel processing with mild facilitatory interactions between global and local information. Thus our results indicate fundamental differences in the stopping rules and channel dependencies in individuals with an ASD.

21 CFR 888.3025 - Passive tendon prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Passive tendon prosthesis. 888.3025 Section 888...) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or a...

21 CFR 888.3025 - Passive tendon prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Passive tendon prosthesis. 888.3025 Section 888...) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or a...

Influence of Second Language Proficiency and Syntactic Structure Similarities on the Sensitivity and Processing of English Passive Sentence in Late Chinese-English Bilinguists: An ERP Study

ERIC Educational Resources Information Center

Chang, Xin; Wang, Pei

2016-01-01

To investigate the influence of L2 proficiency and syntactic similarity on English passive sentence processing, the present ERP study asked 40 late Chinese-English bilinguals (27 females and 13 males, mean age = 23.88) with high or intermediate L2 proficiency to read the sentences carefully and to indicate for each sentence whether or not it was…

Testing thin-skinned inversion of a prerift salt-bearing passive margin (Eastern Prebetic Zone, SE Iberia)

NASA Astrophysics Data System (ADS)

Escosa, Frederic O.; Roca, Eduard; Ferrer, Oriol

2018-04-01

Detailed geologic mapping combined with well and seismic data from the Eastern Prebetic Zone (SE Iberia) reveal extensional and contractional structures that permit characterization of passive margin development and its incorporation into a thin-skinned fold-and-thrust belt. The study area is represented by NW-directed, ENE-trending folds and thrusts faults locally disrupted by the NW-trending Matamoros Basin and the active Jumilla and La Rosa diapirs. These structures resulted from the thin-skinned inversion of the proximal part of the Eastern South Iberian passive margin containing prerift salt. Here, Upper Jurassic to Santonian thick-skinned extension controlled the accumulation of sediment over mobile prerift salt. This in turn defined the style of salt tectonics characterized by monoclinal drape folds, suprasalt extensional faults and diapirs. The structural and sedimentological analysis suggests that during extension, salt localizes strain thus decoupling sub- and suprasalt deformation. Thick-skinned extension controls suprasalt deformation as well as its location and distribution which changes over time. Salt also localizes strain during inversion. The preexisting salt structures, weaker than adjacent areas, preferentially absorb the contractional deformation. In addition, the stepped subsalt geometry that results from thick-skinned extension also controls the shortening propagation. Therefore, the degree of strain localization depends on the thickness of the suprasalt cover and on the dip of subsalt faults relative to the thin-skinned transport direction.

Handbook on passive thermal control coatings

NASA Technical Reports Server (NTRS)

Mookherji, T. K.; Hayes, J. D.

1973-01-01

A handbook of passive thermal control surfaces data pertaining to the heat transfer requirements of spacecraft is presented. Passive temperature control techniques and the selection of control surfaces are analyzed. The space environmental damage mechanisms in passive thermal control surfaces are examined. Data on the coatings for which technical information is available are presented in tabular form. Emphasis was placed on consulting only those references where the experimental simulation of the space environment appeared to be more appropriate.

Cloud and Radiation Mission with Active and Passive Sensing from the Space Station

NASA Technical Reports Server (NTRS)

Spinhirne, James D.

1998-01-01

A cloud and aerosol radiative forcing and physical process study involving active laser and radar profiling with a combination of passive radiometric sounders and imagers would use the space station as an observation platform. The objectives are to observe the full three dimensional cloud and aerosol structure and the associated physical parameters leading to a complete measurement of radiation forcing processes. The instruments would include specialized radar and lidar for cloud and aerosol profiling, visible, infrared and microwave imaging radiometers with comprehensive channels for cloud and aerosol observation and specialized sounders. The low altitude,. available power and servicing capability of the space station are significant advantages for the active sensors and multiple passive instruments.

Hybrid microfluidics combined with active and passive approaches for continuous cell separation.

PubMed

Yan, Sheng; Zhang, Jun; Yuan, Dan; Li, Weihua

2017-01-01

Microfluidics, which is classified as either active or passive, is capable of separating cells of interest from a complex and heterogeneous sample. Active methods utilise external fields such as electric, magnetic, acoustic, and optical to drive cells for separation, while passive methods utilise channel structures, intrinsic hydrodynamic forces, and steric hindrances to manipulate cells. However, when processing complex biological samples such as whole blood with rare cells, separation with a single module microfluidic device is difficult. Hybrid microfluidics is an emerging technique, which utilises active and passive methods whilst fulfilling higher requirements for stable performance, versatility, and convenience, including (i) the ability to process multi-target cells, (ii) enhanced ability for multiplexed separation, (iii) higher sensitivity, and (iv) tunability for a wider operational range. This review introduces the fundamental physics and typical formats for subclasses of hybrid microfluidic devices based on their different physical fields; presents current examples of cell sorting to highlight the advantage and usefulness of hybrid microfluidics on biomedicine, and then discusses the challenges and perspective of future development and the promising direction of research in this field. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bismuth Passivation Technique for High-Resolution X-Ray Detectors

NASA Technical Reports Server (NTRS)

Chervenak, James; Hess, Larry

2013-01-01

The Athena-plus team requires X-ray sensors with energy resolution of better than one part in 3,000 at 6 keV X-rays. While bismuth is an excellent material for high X-ray stopping power and low heat capacity (for large signal when an X-ray is stopped by the absorber), oxidation of the bismuth surface can lead to electron traps and other effects that degrade the energy resolution. Bismuth oxide reduction and nitride passivation techniques analogous to those used in indium passivation are being applied in a new technique. The technique will enable improved energy resolution and resistance to aging in bismuth-absorber-coupled X-ray sensors. Elemental bismuth is lithographically integrated into X-ray detector circuits. It encounters several steps where the Bi oxidizes. The technology discussed here will remove oxide from the surface of the Bi and replace it with nitridized surface. Removal of the native oxide and passivating to prevent the growth of the oxide will improve detector performance and insulate the detector against future degradation from oxide growth. Placing the Bi coated sensor in a vacuum system, a reduction chemistry in a plasma (nitrogen/hydrogen (N2/H2) + argon) is used to remove the oxide and promote nitridization of the cleaned Bi surface. Once passivated, the Bi will perform as a better X-ray thermalizer since energy will not be trapped in the bismuth oxides on the surface. A simple additional step, which can be added at various stages of the current fabrication process, can then be applied to encapsulate the Bi film. After plasma passivation, the Bi can be capped with a non-diffusive layer of metal or dielectric. A non-superconducting layer is required such as tungsten or tungsten nitride (WNx).

Passive Isolators for use on the International Space Station

NASA Technical Reports Server (NTRS)

Houston, Janice; Gattis, Christy

2003-01-01

The value of the International Space Station (ISS) as a premier microgravity environment is currently at risk due to structure-borne vibration. The vibration sources are varied and include crew activities such as exercising or simply moving from module to module, and electro- mechanical equipment such as fans and pumps. Given such potential degradation of usable microgravity, anything that can be done to dampen vibration on-orbit will significantly benefit microgravity users. Most vibration isolation schemes, both active and passive, have proven to be expensive - both operationally and from the cost of integrating isolation systems into primary/secondary structural interfaces (e.g., the ISS module/rack interface). Recently, passively absorptive materials have been tested at the bolt interfaces between the operating equipment and support structure (secondary/tertiary structural interfaces). The results indicate that these materials may prove cost-effective in mitigating the vibrational problems of the ISS. We report herein tests of passive absorbers placed at the interface of a vibration-inducing component: the Development Distillation Assembly, a subassembly of the Urine Processing Assembly, which is a rotating centrifuge and cylinder assembly attached to a mounting plate. Passive isolators were installed between this mounting plate and its support shelf. Three materials were tested: BISCO HT-800, Sorbothane 30 and Sorbothane 50, plus a control test with a hard shim. In addition, four distinct combinations of the HT-800 and Sorbothane 50 were tested. Results show a significant (three orders of magnitude) reduction of transmitted energy, as measured in power spectral density (PSD), using the isolation materials. It is noted, however, that passive materials cannot prevent the transmission of very strong forces or absorb the total energy induced from structural resonances.

On the origin of the photocurrent of electrochemically passivated p-InP(100) photoelectrodes.

PubMed

Goryachev, Andrey; Gao, Lu; van Veldhoven, René P J; Haverkort, Jos E M; Hofmann, Jan P; Hensen, Emiel J M

2018-05-15

III-V semiconductors such as InP are highly efficient light absorbers for photoelectrochemical (PEC) water splitting devices. Yet, their cathodic stability is limited due to photocorrosion and the measured photocurrents do not necessarily originate from H2 evolution only. We evaluated the PEC stability and activation of model p-InP(100) photocathodes upon photoelectrochemical passivation (i.e. repeated surface oxidation/reduction). The electrode was subjected to a sequence of linear potential scans with or without intermittent passivation steps (repeated passivation and continuous reduction, respectively). The evolution of H2 and PH3 gases was monitored by online electrochemical mass spectrometry (OLEMS) and the Faradaic efficiencies of these processes were determined. Repeated passivation led to an increase of the photocurrent in 0.5 M H2SO4, while continuous reduction did not affect the photocurrent of p-InP(100). Neither H2 nor PH3 formation increased to the same extent as the photocurrent during the repeated passivation treatment. Surface analysis of the spent electrodes revealed substantial roughening of the electrode surface by repeated passivation, while continuous reduction left the surface unaltered. On the other hand, photocathodic conditioning performed in 0.5 M HCl led to the expected correlation between photocurrent increase and H2 formation. Ultimately, the H2 evolution rates of the photoelectrodes in H2SO4 and HCl are comparable. The much higher photocurrent in H2SO4 is due to competing side-reactions. The results emphasize the need for a detailed evaluation of the Faradaic efficiencies of all the involved processes using a chemical-specific technique like OLEMS. Photo-OLEMS can be beneficial in the study of photoelectrochemical reactions enabling the instantaneous detection of small amounts of reaction by-products.

Extracting atmospheric turbulence and aerosol characteristics from passive imagery

NASA Astrophysics Data System (ADS)

Reinhardt, Colin N.; Wayne, D.; McBryde, K.; Cauble, G.

2013-09-01

Obtaining accurate, precise and timely information about the local atmospheric turbulence and extinction conditions and aerosol/particulate content remains a difficult problem with incomplete solutions. It has important applications in areas such as optical and IR free-space communications, imaging systems performance, and the propagation of directed energy. The capability to utilize passive imaging data to extract parameters characterizing atmospheric turbulence and aerosol/particulate conditions would represent a valuable addition to the current piecemeal toolset for atmospheric sensing. Our research investigates an application of fundamental results from optical turbulence theory and aerosol extinction theory combined with recent advances in image-quality-metrics (IQM) and image-quality-assessment (IQA) methods. We have developed an algorithm which extracts important parameters used for characterizing atmospheric turbulence and extinction along the propagation channel, such as the refractive-index structure parameter C2n , the Fried atmospheric coherence width r0 , and the atmospheric extinction coefficient βext , from passive image data. We will analyze the algorithm performance using simulations based on modeling with turbulence modulation transfer functions. An experimental field campaign was organized and data were collected from passive imaging through turbulence of Siemens star resolution targets over several short littoral paths in Point Loma, San Diego, under conditions various turbulence intensities. We present initial results of the algorithm's effectiveness using this field data and compare against measurements taken concurrently with other standard atmospheric characterization equipment. We also discuss some of the challenges encountered with the algorithm, tasks currently in progress, and approaches planned for improving the performance in the near future.

Development of Verbal Passive in Williams Syndrome

ERIC Educational Resources Information Center

Perovic, Alexandra; Wexler, Kenneth

2010-01-01

Purpose: To experimentally investigate knowledge of passives of actional ("hold") and psychological ("love") verbs in children with Williams syndrome (WS). Passives are usually reported to be in line with mental age in WS. However, studies usually focus on passives of actional verbs only. Method: Twenty-six children with WS, ages 6-16, and 3…

26 CFR 1.1398-1 - Treatment of passive activity losses and passive activity credits in individuals' title 11 cases.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 11 2011-04-01 2011-04-01 false Treatment of passive activity losses and passive activity credits in individuals' title 11 cases. 1.1398-1 Section 1.1398-1 Internal Revenue... (CONTINUED) Rules Relating to Individuals' Title 11 Cases § 1.1398-1 Treatment of passive activity losses and...

Molecular Gas Contents and Scaling Relations for Massive, Passive Galaxies at Intermediate Redshifts from the LEGA-C Survey

NASA Astrophysics Data System (ADS)

Spilker, Justin; Bezanson, Rachel; Barišić, Ivana; Bell, Eric; Lagos, Claudia del P.; Maseda, Michael; Muzzin, Adam; Pacifici, Camilla; Sobral, David; Straatman, Caroline; van der Wel, Arjen; van Dokkum, Pieter; Weiner, Benjamin; Whitaker, Katherine; Williams, Christina C.; Wu, Po-Feng

2018-06-01

A decade of study has established that the molecular gas properties of star-forming galaxies follow coherent scaling relations out to z ∼ 3, suggesting remarkable regularity of the interplay between molecular gas, star formation, and stellar growth. Passive galaxies, however, are expected to be gas-poor and therefore faint, and thus little is known about molecular gas in passive galaxies beyond the local universe. Here we present deep Atacama Large Millimeter/submillimeter Array observations of CO(2–1) emission in eight massive (M star ∼ 1011 M ⊙) galaxies at z ∼ 0.7 selected to lie a factor of 3–10 below the star-forming sequence at this redshift, drawn from the Large Early Galaxy Astrophysics Census survey. We significantly detect half the sample, finding molecular gas fractions ≲0.1. We show that the molecular and stellar rotational axes are broadly consistent, arguing that the molecular gas was not accreted after the galaxies became quiescent. We find that scaling relations extrapolated from the star-forming population overpredict both the gas fraction and gas depletion time for passive objects, suggesting the existence of either a break or large increase in scatter in these relations at low specific star formation rate. Finally, we show that the gas fractions of the passive galaxies we have observed at intermediate redshifts are naturally consistent with evolution into local, massive early-type galaxies by continued low-level star formation, with no need for further gas accretion or dynamical stabilization of the gas reservoirs in the intervening 6 billion years.

Passive fiber alignment to single-mode plastic waveguides fabricated by injection molding

NASA Astrophysics Data System (ADS)

Pompe, Guido; Lehmacher, Stefan; Rudolph, Stefan; Kalveram, Stefan; Joenck, Matthias; Neyer, Andreas

1998-04-01

Passive fibre-waveguide coupling is a promising alternative to expensive active coupling in single-mode fibre-optics. The idea to utilize replication techniques in transparent polymeric materials for waveguide and alignment structure fabrication has led to the SIGA-process (Silizium, Galvanik und Abformung) which allows a cost effective production of low loss polymer waveguides in the near IR. Major difficulties in passive fibre coupling are caused by the high lateral alignment accuracy (of about 1 micrometer) in fibre positioning. In the SIGA process, the exact position of the V- grooves relative to the waveguide trenches is defined by the etch mask for the silicon master wafer. The width of the V- grooves is determined by the KOH etching time. It is controlled precisely at various stages in the etching process by means of a microscope based piezo driven measurement system with a resolution better than 0.5 micrometer, thus allowing a final vertical precision of fibre positioning of 350 nm. In order to specify the capability of our technology we have measured the position of dozens of fibres glued into V- grooves. The result was that an amount of 55% of the fibre cores was closer than 1.5 micrometer to the waveguide centre. As the experience has shown, a two-step process for the fabrication of passively fibre coupled waveguides is necessary. First, the waveguides are produced by filling the waveguide trenches with an IR-transparent monomer and by polymerizing it using UV curing. The waveguides are inspected with visible and IR light by clamping a fibre ribbon mechanically into the integrated plastic V-grooves. In a second step the fibre ribbon is fixed irreversibly in the V- grooves. By that way we have reached an insertion loss of 3.5 dB at 1300nm and 1550nm for passively coupled 22mm single mode waveguides. Most of the losses are attributed to waveguide imperfections. More details concerning the coupling losses and the device performances will be reported at the

Energy extraction from a semi-passive flapping-foil turbine with active heave and passive pitch

NASA Astrophysics Data System (ADS)

Boudreau, Matthieu; Dumas, Guy; Gunther, Kevin; CFD Laboratory LMFN Team

2017-11-01

Due to the inherent complexity of the mechanisms needed to prescribe the heaving and the pitching motions of optimal flapping-foil turbines, several research groups are now investigating the potential of using unconstrained passive motions. The amplitude, the phase and the frequency of such free motions are thus the result of the interaction of the blade with the flow and its elastic supports, namely springs and dampers. In parallel with our current study on fully-passive flapping-foil turbines, we investigate in this work the possibility of using a semi-passive turbine. Unlike previous semi-passive turbines studied in the literature, we propose a turbine with a passive pitching motion and an active heaving motion constrained to be a sine wave with desired amplitude and frequency. As most of the energy extracted by flapping-foil turbines comes from the heaving motion, it is natural to connect an electric generator to this degree of freedom, thereby allowing one to constrain this motion. It is found that large-amplitude pitching motions leading to a considerable energy extraction can arise under different circumstances and mechanisms, either forced by the heaving motion or driven by an instability of the pitching motion itself. The authors gratefully acknowledge the support from the Natural Sciences and Engineering Research Council of Canada (NSERC), the Tyler Lewis Clean Energy Research Foundation, Calcul Québec and Compute Canada.

Silicon surface passivation by silicon nitride deposition

NASA Technical Reports Server (NTRS)

Olsen, L. C.

1984-01-01

Silicon nitride deposition was studied as a method of passivation for silicon solar cell surfaces. The following three objectives were the thrust of the research: (1) the use of pecvd silicon nitride for passivation of silicon surfaces; (2) measurement techniques for surface recombination velocity; and (3) the importance of surface passivation to high efficiency solar cells.

New Insights on Mt. Etna's Crust and Relationship with the Regional Tectonic Framework from Joint Active and Passive P-Wave Seismic Tomography

NASA Astrophysics Data System (ADS)

Díaz-Moreno, A.; Barberi, G.; Cocina, O.; Koulakov, I.; Scarfì, L.; Zuccarello, L.; Prudencio, J.; García-Yeguas, A.; Álvarez, I.; García, L.; Ibáñez, J. M.

2018-01-01

In the Central Mediterranean region, the production of chemically diverse volcanic products (e.g., those from Mt. Etna and the Aeolian Islands archipelago) testifies to the complexity of the tectonic and geodynamic setting. Despite the large number of studies that have focused on this area, the relationships among volcanism, tectonics, magma ascent, and geodynamic processes remain poorly understood. We present a tomographic inversion of P-wave velocity using active and passive sources. Seismic signals were recorded using both temporary on-land and ocean bottom seismometers and data from a permanent local seismic network consisting of 267 seismic stations. Active seismic signals were generated using air gun shots mounted on the Spanish Oceanographic Vessel `Sarmiento de Gamboa'. Passive seismic sources were obtained from 452 local earthquakes recorded over a 4-month period. In total, 184,797 active P-phase and 11,802 passive P-phase first arrivals were inverted to provide three different velocity models. Our results include the first crustal seismic active tomography for the northern Sicily area, including the Peloritan-southern Calabria region and both the Mt. Etna and Aeolian volcanic environments. The tomographic images provide a detailed and complete regional seismotectonic framework and highlight a spatially heterogeneous tectonic regime, which is consistent with and extends the findings of previous models. One of our most significant results was a tomographic map extending to 14 km depth showing a discontinuity striking roughly NW-SE, extending from the Gulf of Patti to the Ionian Sea, south-east of Capo Taormina, corresponding to the Aeolian-Tindari-Letojanni fault system, a regional deformation belt. Moreover, for the first time, we observed a high-velocity anomaly located in the south-eastern sector of the Mt. Etna region, offshore of the Timpe area, which is compatible with the plumbing system of an ancient shield volcano located offshore of Mt. Etna.

ERP correlates of object recognition memory in Down syndrome: Do active and passive tasks measure the same thing?

PubMed

Van Hoogmoed, A H; Nadel, L; Spanò, G; Edgin, J O

2016-02-01

Event related potentials (ERPs) can help to determine the cognitive and neural processes underlying memory functions and are often used to study populations with severe memory impairment. In healthy adults, memory is typically assessed with active tasks, while in patient studies passive memory paradigms are generally used. In this study we examined whether active and passive continuous object recognition tasks measure the same underlying memory process in typically developing (TD) adults and in individuals with Down syndrome (DS), a population with known hippocampal impairment. We further explored how ERPs in these tasks relate to behavioral measures of memory. Data-driven analysis techniques revealed large differences in old-new effects in the active versus passive task in TD adults, but no difference between these tasks in DS. The group with DS required additional processing in the active task in comparison to the TD group in two ways. First, the old-new effect started 150 ms later. Second, more repetitions were required to show the old-new effect. In the group with DS, performance on a behavioral measure of object-location memory was related to ERP measures across both tasks. In total, our results suggest that active and passive ERP memory measures do not differ in DS and likely reflect the use of implicit memory, but not explicit processing, on both tasks. Our findings highlight the need for a greater understanding of the comparison between active and passive ERP paradigms before they are inferred to measure similar functions across populations (e.g., infants or intellectual disability). Copyright © 2016 Elsevier Ltd. All rights reserved.

Passivation and Depassivation of Defects in Graphene-based field-effect transistors

NASA Astrophysics Data System (ADS)

O'Hara, Andrew; Wang, Pan; Perini, Chris J.; Fleetwood, Daniel M.; Vogel, Eric M.; Pantelides, Sokrates T.

Field effect transistors based on graphene on amorphous SiO2 substrates were fabricated, both with and without a top oxide passivation layer of Al2O3. Initial I-V characteristics of these devices show that the Fermi energy occurs below the Dirac point in graphene (i.e. p-type behavior). Introduction of environmental stresses, e.g. baking the devices, causes a shift in the Fermi energy relative to the Dirac point. 1/f noise measurements indicate the presence of charge trapping defects. In order to find the origins of this behavior, we construct atomistic models of the substrate/graphene interface and the graphene/oxide passivation layer interface. Using density functional theory, we investigate the role that the introduction and removal of hydrogen and hydroxide passivants has on the electronic structure of the graphene layer as well as the relative energetics for these processes to occur in order to gain insights into the experimental results. Supported by DTRA: 1-16-0032 and NSF: ECCS-1508898.

Separating Active and Passive Influences on Stomatal Control of Transpiration[OPEN

PubMed Central

McAdam, Scott A.M.; Brodribb, Timothy J.

2014-01-01

Motivated by studies suggesting that the stomata of ferns and lycophytes do not conform to the standard active abscisic acid (ABA) -mediated stomatal control model, we examined stomatal behavior in a conifer species (Metasequoia glyptostroboides) that is phylogenetically midway between the fern and angiosperm clades. Similar to ferns, daytime stomatal closure in response to moderate water stress seemed to be a passive hydraulic process in M. glyptostroboides immediately alleviated by rehydrating excised shoots. Only after prolonged exposure to more extreme water stress did active ABA-mediated stomatal closure become important, because foliar ABA production was triggered after leaf turgor loss. The influence of foliar ABA on stomatal conductance and stomatal aperture was highly predictable and additive with the passive hydraulic influence. M. glyptostroboides thus occupies a stomatal behavior type intermediate between the passively controlled ferns and the characteristic ABA-dependent stomatal closure described in angiosperm herbs. These results highlight the importance of considering phylogeny as a major determinant of stomatal behavior. PMID:24488969

Three-input gate logic circuits on chemically assembled single-electron transistors with organic and inorganic hybrid passivation layers

PubMed Central

Majima, Yutaka; Hackenberger, Guillaume; Azuma, Yasuo; Kano, Shinya; Matsuzaki, Kosuke; Susaki, Tomofumi; Sakamoto, Masanori; Teranishi, Toshiharu

2017-01-01

Abstract Single-electron transistors (SETs) are sub-10-nm scale electronic devices based on conductive Coulomb islands sandwiched between double-barrier tunneling barriers. Chemically assembled SETs with alkanethiol-protected Au nanoparticles show highly stable Coulomb diamonds and two-input logic operations. The combination of bottom-up and top-down processes used to form the passivation layer is vital for realizing multi-gate chemically assembled SET circuits, as this combination enables us to connect conventional complementary metal oxide semiconductor (CMOS) technologies via planar processes. Here, three-input gate exclusive-OR (XOR) logic operations are demonstrated in passivated chemically assembled SETs. The passivation layer is a hybrid bilayer of self-assembled monolayers (SAMs) and pulsed laser deposited (PLD) aluminum oxide (AlOx), and top-gate electrodes were prepared on the hybrid passivation layers. Top and two-side-gated SETs showed clear Coulomb oscillation and diamonds for each of the three available gates, and three-input gate XOR logic operation was clearly demonstrated. These results show the potential of chemically assembled SETs to work as logic devices with multi-gate inputs using organic and inorganic hybrid passivation layers. PMID:28634499

Three-input gate logic circuits on chemically assembled single-electron transistors with organic and inorganic hybrid passivation layers.

PubMed

Majima, Yutaka; Hackenberger, Guillaume; Azuma, Yasuo; Kano, Shinya; Matsuzaki, Kosuke; Susaki, Tomofumi; Sakamoto, Masanori; Teranishi, Toshiharu

2017-01-01

Single-electron transistors (SETs) are sub-10-nm scale electronic devices based on conductive Coulomb islands sandwiched between double-barrier tunneling barriers. Chemically assembled SETs with alkanethiol-protected Au nanoparticles show highly stable Coulomb diamonds and two-input logic operations. The combination of bottom-up and top-down processes used to form the passivation layer is vital for realizing multi-gate chemically assembled SET circuits, as this combination enables us to connect conventional complementary metal oxide semiconductor (CMOS) technologies via planar processes. Here, three-input gate exclusive-OR (XOR) logic operations are demonstrated in passivated chemically assembled SETs. The passivation layer is a hybrid bilayer of self-assembled monolayers (SAMs) and pulsed laser deposited (PLD) aluminum oxide (AlO[Formula: see text]), and top-gate electrodes were prepared on the hybrid passivation layers. Top and two-side-gated SETs showed clear Coulomb oscillation and diamonds for each of the three available gates, and three-input gate XOR logic operation was clearly demonstrated. These results show the potential of chemically assembled SETs to work as logic devices with multi-gate inputs using organic and inorganic hybrid passivation layers.

Two-step simulation of velocity and passive scalar mixing at high Schmidt number in turbulent jets

NASA Astrophysics Data System (ADS)

Rah, K. Jeff; Blanquart, Guillaume

2016-11-01

Simulation of passive scalar in the high Schmidt number turbulent mixing process requires higher computational cost than that of velocity fields, because the scalar is associated with smaller length scales than velocity. Thus, full simulation of both velocity and passive scalar with high Sc for a practical configuration is difficult to perform. In this work, a new approach to simulate velocity and passive scalar mixing at high Sc is suggested to reduce the computational cost. First, the velocity fields are resolved by Large Eddy Simulation (LES). Then, by extracting the velocity information from LES, the scalar inside a moving fluid blob is simulated by Direct Numerical Simulation (DNS). This two-step simulation method is applied to a turbulent jet and provides a new way to examine a scalar mixing process in a practical application with smaller computational cost. NSF, Samsung Scholarship.

Discreet passive explosive detection through 2-sided waveguided fluorescence

DOEpatents

Harper, Ross James [Stillwater, OK; la Grone, Marcus [Cushing, OK; Fisher, Mark [Stillwater, OK

2011-10-18

The current invention provides a passive sampling device suitable for collecting and detecting the presence of target analytes. In particular, the passive sampling device is suitable for detecting nitro-aromatic compounds. The current invention further provides a passive sampling device reader suitable for determining the collection of target analytes. Additionally, the current invention provides methods for detecting target analytes using the passive sampling device and the passive sampling device reader.

Gestalt Perception and Local-Global Processing in High-Functioning Autism

ERIC Educational Resources Information Center

Bolte, Sven; Holtmann, Martin; Poustka, Fritz; Scheurich, Armin; Schmidt, Lutz

2007-01-01

This study examined gestalt perception in high-functioning autism (HFA) and its relation to tasks indicative of local visual processing. Data on of gestalt perception, visual illusions (VI), hierarchical letters (HL), Block Design (BD) and the Embedded Figures Test (EFT) were collected in adult males with HFA, schizophrenia, depression and…

The passive control of air pollution exposure in Dublin, Ireland: a combined measurement and modelling case study.

PubMed

Gallagher, J; Gill, L W; McNabola, A

2013-08-01

This study investigates the potential real world application of passive control systems to reduce personal pollutant exposure in an urban street canyon in Dublin, Ireland. The implementation of parked cars and/or low boundary walls as a passive control system has been shown to minimise personal exposure to pollutants on footpaths in previous investigations. However, previous research has been limited to generic numerical modelling studies. This study combines real-time traffic data, meteorological conditions and pollution concentrations, in a real world urban street canyon before and after the implementation of a passive control system. Using a combination of field measurements and numerical modelling this study assessed the potential impact of passive controls on personal exposure to nitric oxide (NO) concentrations in the street canyon in winter conditions. A calibrated numerical model of the urban street canyon was developed, taking into account the variability in traffic and meteorological conditions. The modelling system combined the computational fluid dynamic (CFD) simulations and a semi-empirical equation, and demonstrated a good agreement with measured field data collected in the street canyon. The results indicated that lane distribution, fleet composition and vehicular turbulence all affected pollutant dispersion, in addition to the canyon geometry and local meteorological conditions. The introduction of passive controls displayed mixed results for improvements in air quality on the footpaths for different wind and traffic conditions. Parked cars demonstrated the most comprehensive passive control system with average improvements in air quality of up to 15% on the footpaths. This study highlights the potential of passive controls in a real street canyon to increase dispersion and improve air quality at street level. Copyright © 2013 Elsevier B.V. All rights reserved.

Amorphous silicon carbide passivating layers for crystalline-silicon-based heterojunction solar cells

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

Boccard, Mathieu; Holman, Zachary C.

Amorphous silicon enables the fabrication of very high-efficiency crystalline-silicon-based solar cells due to its combination of excellent passivation of the crystalline silicon surface and permeability to electrical charges. Yet, amongst other limitations, the passivation it provides degrades upon high-temperature processes, limiting possible post-deposition fabrication possibilities (e.g., forcing the use of low-temperature silver pastes). We investigate the potential use of intrinsic amorphous silicon carbide passivating layers to sidestep this issue. The passivation obtained using device-relevant stacks of intrinsic amorphous silicon carbide with various carbon contents and doped amorphous silicon are evaluated, and their stability upon annealing assessed, amorphous silicon carbide beingmore » shown to surpass amorphous silicon for temperatures above 300 °C. We demonstrate open-circuit voltage values over 700 mV for complete cells, and an improved temperature stability for the open-circuit voltage. Transport of electrons and holes across the hetero-interface is studied with complete cells having amorphous silicon carbide either on the hole-extracting side or on the electron-extracting side, and a better transport of holes than of electrons is shown. Also, due to slightly improved transparency, complete solar cells using an amorphous silicon carbide passivation layer on the hole-collecting side are demonstrated to show slightly better performances even prior to annealing than obtained with a standard amorphous silicon layer.« less

Amorphous silicon carbide passivating layers for crystalline-silicon-based heterojunction solar cells

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

Boccard, Mathieu; Holman, Zachary C.

With this study, amorphous silicon enables the fabrication of very high-efficiency crystalline-silicon-based solar cells due to its combination of excellent passivation of the crystalline silicon surface and permeability to electrical charges. Yet, amongst other limitations, the passivation it provides degrades upon high-temperature processes, limiting possible post-deposition fabrication possibilities (e.g., forcing the use of low-temperature silver pastes). We investigate the potential use of intrinsic amorphous silicon carbide passivating layers to sidestep this issue. The passivation obtained using device-relevant stacks of intrinsic amorphous silicon carbide with various carbon contents and doped amorphous silicon are evaluated, and their stability upon annealing assessed, amorphousmore » silicon carbide being shown to surpass amorphous silicon for temperatures above 300°C. We demonstrate open-circuit voltage values over 700 mV for complete cells, and an improved temperature stability for the open-circuit voltage. Transport of electrons and holes across the hetero-interface is studied with complete cells having amorphous silicon carbide either on the hole-extracting side or on the electron-extracting side, and a better transport of holes than of electrons is shown. Also, due to slightly improved transparency, complete solar cells using an amorphous silicon carbide passivation layer on the hole-collecting side are demonstrated to show slightly better performances even prior to annealing than obtained with a standard amorphous silicon layer.« less

Amorphous silicon carbide passivating layers for crystalline-silicon-based heterojunction solar cells

DOE PAGES

Boccard, Mathieu; Holman, Zachary C.

2015-08-14

With this study, amorphous silicon enables the fabrication of very high-efficiency crystalline-silicon-based solar cells due to its combination of excellent passivation of the crystalline silicon surface and permeability to electrical charges. Yet, amongst other limitations, the passivation it provides degrades upon high-temperature processes, limiting possible post-deposition fabrication possibilities (e.g., forcing the use of low-temperature silver pastes). We investigate the potential use of intrinsic amorphous silicon carbide passivating layers to sidestep this issue. The passivation obtained using device-relevant stacks of intrinsic amorphous silicon carbide with various carbon contents and doped amorphous silicon are evaluated, and their stability upon annealing assessed, amorphousmore » silicon carbide being shown to surpass amorphous silicon for temperatures above 300°C. We demonstrate open-circuit voltage values over 700 mV for complete cells, and an improved temperature stability for the open-circuit voltage. Transport of electrons and holes across the hetero-interface is studied with complete cells having amorphous silicon carbide either on the hole-extracting side or on the electron-extracting side, and a better transport of holes than of electrons is shown. Also, due to slightly improved transparency, complete solar cells using an amorphous silicon carbide passivation layer on the hole-collecting side are demonstrated to show slightly better performances even prior to annealing than obtained with a standard amorphous silicon layer.« less

Enhanced Carrier Collection from CdS Passivated Grains in Solution-Processed Cu2ZnSn(S,Se)4 Solar Cells.

PubMed

Werner, Melanie; Keller, Debora; Haass, Stefan G; Gretener, Christina; Bissig, Benjamin; Fuchs, Peter; La Mattina, Fabio; Erni, Rolf; Romanyuk, Yaroslav E; Tiwari, Ayodhya N

2015-06-10

Solution processing of Cu2ZnSn(S,Se)4 (CZTSSe)-kesterite solar cells is attractive because of easy manufacturing using readily available metal salts. The solution-processed CZTSSe absorbers, however, often suffer from poor morphology with a bilayer structure, exhibiting a dense top crust and a porous bottom layer, albeit yielding efficiencies of over 10%. To understand whether the cell performance is limited by this porous layer, a systematic compositional study using (scanning) transmission electron microscopy ((S)TEM) and energy-dispersive X-ray spectroscopy of the dimethyl sulfoxide processed CZTSSe absorbers is presented. TEM investigation revealed a thin layer of CdS that is formed around the small CZTSSe grains in the porous bottom layer during the chemical bath deposition step. This CdS passivation is found to be beneficial for the cell performance as it increases the carrier collection and facilitates the electron transport. Electron-beam-induced current measurements reveal an enhanced carrier collection for this buried region as compared to reference cells with evaporated CdS.

Quantifying the thermal evolution of early passive margins formation and its consequences on the structure of passive margins

NASA Astrophysics Data System (ADS)

Bousquet, Romain; Nalpas, Thierry

2017-04-01

Many large-scale dynamic processes, from continental rifting to plate subduction, are intimately linked to metamorphic reactions. This close relation between geodynamic processes and metamorphic reactions is, in spite of appearances, yet poorly understood. For example, during extension processes, rocks will be exposed to important temperature, pressures and stress changes. Meanwhile less attention has been paid to other important aspects of the metamorphic processes. When reacting rocks expand and contract, density and volume changes will set up in the surrounding material. While several tectonic models are proposed to explain the formation of extensive basins and passive margins ( simple shear detachment mantle exhumation .... ) a single thermal model (McKenzie, 1978), as a kind of dogma, is used to understanding and modeling the formation and evolution of sedimentary basins. The study of the thermal evolution, coupled with other tectonic models, and its consequences have never been studied in detail, although the differences may be significant. And it is clear that the petrological changes associated with changes in temperature conditions, influence changes reliefs. Constrained by the new field data of north Pyrenean basins on thermal evolution of pre-rift and syn-rift sediments, we explore the petrological changes associated to different thermal evolution and the consequences on the subsidence of the basins. We will also present numerical models quantifying mineralogical and physical changes inside the whole lithosphere during rifting processes. In the light of these models, we discuss the consequences of different thermal evolution on the subsidence processes as well as on gravimetry and seismic velocities signature of passive margins. We are able to distinguish two types of margins according to their thermal evolution: - An Alpine-type basin in which the temperature rise is 50 to 100 Ma older than the tectonic extension, leading to the "cold" opening of the

Possibility of passive THz camera using for a temperature difference observing of objects placed inside the human body

NASA Astrophysics Data System (ADS)

Trofimov, Vyacheslav A.; Trofimov, Vladislav V.; Kuchik, Igor E.

2014-06-01

As it is well-known, application of the passive THz camera for the security problems is very promising way. It allows seeing concealed object without contact with a person and this camera is non-dangerous for a person. We demonstrate new possibility of the passive THz camera using for a temperature difference observing on the human skin if this difference is caused by different temperatures inside the body. We discuss some physical experiments, in which a person drinks hot, and warm, and cold water and he eats. After computer processing of images captured by passive THz camera TS4 we may see the pronounced temperature trace on skin of the human body. For proof of validity of our statement we make the similar physical experiment using the IR camera. Our investigation allows to increase field of the passive THz camera using for the detection of objects concealed in the human body because the difference in temperature between object and parts of human body will be reflected on the human skin. However, modern passive THz cameras have not enough resolution in a temperature to see this difference. That is why, we use computer processing to enhance the camera resolution for this application. We consider images produced by THz passive cameras manufactured by Microsemi Corp., and ThruVision Corp.

Determination of the strain distribution for the Si3N4 passivated AlGaN/AlN/GaN heterostructure field-effect transistors

NASA Astrophysics Data System (ADS)

Fu, Chen; Lin, Zhaojun; Liu, Yan; Cui, Peng; Lv, Yuanjie; Zhou, Yang; Dai, Gang; Luan, Chongbiao

2017-11-01

A method to determine the strain distribution of the AlGaN barrier layer after the device fabrication and the passivation process has been presented. By fitting the calculated parasitic source access resistance with the measured ones for the AlGaN/AlN/GaN HFETs and using the polarization Coulomb field scattering theory, the strain variation of the AlGaN barrier layer after the passivation process has been quantitatively studied. The results show that the tensile strain in the access regions of the AlGaN barrier layer has been increased by 4.62% for the 250 nm-Si3N4 passivated device, and has been decreased by 2.0% for the 400 nm-Si3N4 passivated device, compared to that of before the passivation, respectively. For the gate region of the two devices, the tensile strain has been decreased by 60.77% and increased by 3.60% after the passivation of different thicknesses, oppositely.

Perception of Shapes Targeting Local and Global Processes in Autism Spectrum Disorders

ERIC Educational Resources Information Center

Grinter, Emma J.; Maybery, Murray T.; Pellicano, Elizabeth; Badcock, Johanna C.; Badcock, David R.

2010-01-01

Background: Several researchers have found evidence for impaired global processing in the dorsal visual stream in individuals with autism spectrum disorders (ASDs). However, support for a similar pattern of visual processing in the ventral visual stream is less consistent. Critical to resolving the inconsistency is the assessment of local and…

Modeling of Passive Forces of Machine Tool Covers

NASA Astrophysics Data System (ADS)

Kolar, Petr; Hudec, Jan; Sulitka, Matej

The passive forces acting against the drive force are phenomena that influence dynamical properties and precision of linear axes equipped with feed drives. Covers are one of important sources of passive forces in machine tools. The paper describes virtual evaluation of cover passive forces using the cover complex model. The model is able to compute interaction between flexible cover segments and sealing wiper. The result is deformation of cover segments and wipers which is used together with measured friction coefficient for computation of cover total passive force. This resulting passive force is dependent on cover position. Comparison of computational results and measurement on the real cover is presented in the paper.

An investigation into the effective surface passivation of quantum dots by a photo-assisted chemical method

NASA Astrophysics Data System (ADS)

Joo, So-Yeong; Park, Hyun-Su; Kim, Do-yeon; Kim, Bum-Sung; Lee, Chan Gi; Kim, Woo-Byoung

2018-01-01

In this study, we have developed an effective amino passivation process for quantum dots (QDs) at room temperature and have investigated a passivation mechanism using a photo-assisted chemical method. As a result of the reverse reaction of the H2O molecules, the etching kinetics of the photo-assisted chemical method increased upon increasing the 3-amino-1-propanol (APOL)/H2O ratio of the etching solution. Photon-excited electron-hole pairs lead to strong bonding between the organic and surface atoms of the QDs, and results in an increase of the quantum yield (QY%). This passivation method is also applicable to CdSe/ZnSe core/shell structures of QDs, due to the passivation of mid-gap defects states at the interface. The QY% of the as-synthesized CdSe QDs is dramatically enhanced by the amino passivation from 37% to 75% and the QY% of the CdSe/ZnSe core/shell QDs is also improved by ˜28%.

Using paired visual and passive acoustic surveys to estimate passive acoustic detection parameters for harbor porpoise abundance estimates.

PubMed

Jacobson, Eiren K; Forney, Karin A; Barlow, Jay

2017-01-01

Passive acoustic monitoring is a promising approach for monitoring long-term trends in harbor porpoise (Phocoena phocoena) abundance. Before passive acoustic monitoring can be implemented to estimate harbor porpoise abundance, information about the detectability of harbor porpoise is needed to convert recorded numbers of echolocation clicks to harbor porpoise densities. In the present study, paired data from a grid of nine passive acoustic click detectors (C-PODs, Chelonia Ltd., United Kingdom) and three days of simultaneous aerial line-transect visual surveys were collected over a 370 km 2 study area. The focus of the study was estimating the effective detection area of the passive acoustic sensors, which was defined as the product of the sound production rate of individual animals and the area within which those sounds are detected by the passive acoustic sensors. Visually estimated porpoise densities were used as informative priors in a Bayesian model to solve for the effective detection area for individual harbor porpoises. This model-based approach resulted in a posterior distribution of the effective detection area of individual harbor porpoises consistent with previously published values. This technique is a viable alternative for estimating the effective detection area of passive acoustic sensors when other experimental approaches are not feasible.

International Workshop on Detection, Classification and Localization of Marine Mammals Using Passive Acoustics (4th). International Workshop on Density Estimation of Marine Mammals Using Passive Acoustics (1st)

DTIC Science & Technology

2009-09-13

University of Singapore) Olivier Adam (NAMC, Univ. of Paris , France) Len Thomas (Univ St Andrews, Scotland; convenor of the DE workshop...Hervé, Paris Sébastien 90 3 - The Continuous Development for Passive Acoustic Monitoring in Offshore Commercial Industry A. Cucknell and N. Clark...encourage researchers to work on a common dataset, to focus on the same problems, to find original solutions, and to present and compare them at the

Systematic review of smartphone-based passive sensing for health and wellbeing.

PubMed

Cornet, Victor P; Holden, Richard J

2018-01-01

To review published empirical literature on the use of smartphone-based passive sensing for health and wellbeing. A systematic review of the English language literature was performed following PRISMA guidelines. Papers indexed in computing, technology, and medical databases were included if they were empirical, focused on health and/or wellbeing, involved the collection of data via smartphones, and described the utilized technology as passive or requiring minimal user interaction. Thirty-five papers were included in the review. Studies were performed around the world, with samples of up to 171 (median n = 15) representing individuals with bipolar disorder, schizophrenia, depression, older adults, and the general population. The majority of studies used the Android operating system and an array of smartphone sensors, most frequently capturing accelerometry, location, audio, and usage data. Captured data were usually sent to a remote server for processing but were shared with participants in only 40% of studies. Reported benefits of passive sensing included accurately detecting changes in status, behavior change through feedback, and increased accountability in participants. Studies reported facing technical, methodological, and privacy challenges. Studies in the nascent area of smartphone-based passive sensing for health and wellbeing demonstrate promise and invite continued research and investment. Existing studies suffer from weaknesses in research design, lack of feedback and clinical integration, and inadequate attention to privacy issues. Key recommendations relate to developing passive sensing strategies matching the problem at hand, using personalized interventions, and addressing methodological and privacy challenges. As evolving passive sensing technology presents new possibilities for health and wellbeing, additional research must address methodological, clinical integration, and privacy issues. Doing so depends on interdisciplinary collaboration

Self-passivation Rule and the Effect of Post-treatment in GBs of Solar Cell Materials

NASA Astrophysics Data System (ADS)

Liu, Chengyan; Chen, Shiyou; Xiang, Hongjun; Gong, Xingao

Grain boundaries (GBs) existing in polycrystalline semiconductors alloys inducing a great deal of deep defect levels are usually harmful to cells' photovoltaic performance. Experimental and theoretical investigations verified that these defect levels come from the GBs' dangling bonds. We find that, the defect levels in anion core of GB can be passivated by its cations, called by self-passivation. For instance, the post-treated by CdCl2, Cd can eliminate the defect levels by saturating Te dangling bonds in the grain boundary of CdTe. We verify that the idea of self-passivation rule can perfectly explain the benign GBs of CISe and CZTS by sodium treatment. The present work reveals a general mechanism about how dopants in GBs eliminate the defect states through passivating the dangling bonds in covalent polycrystalline semiconductors, and sheds light on how to passivate dangling bonds in GBs with alterative processes. National Science Foundation of China, international collaboration project of MOST, Pujiang plan, Program for Professor of Special Appointment (Eastern Scholar), and Shanghai Rising-star program.

76 FR 72875 - Passive Activity Losses and Credits Limited

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-28

... Passive Activity Losses and Credits Limited AGENCY: Internal Revenue Service (IRS), Treasury. ACTION... losses from passive activities. Section 469(b) permits passive losses disallowed in one year to be carried over to the next year. Section 469(c)(1) provides that a passive activity means any activity which...

Reducing the cytotoxicity of inhalable engineered nanoparticles via in situ passivation with biocompatible materials.

PubMed

Byeon, Jeong Hoon; Park, Jae Hong; Peters, Thomas M; Roberts, Jeffrey T

2015-07-15

The cytotoxicity of model welding nanoparticles was modulated through in situ passivation with soluble biocompatible materials. A passivation process consisting of a spark discharge particle generator coupled to a collison atomizer as a co-flow or counter-flow configuration was used to incorporate the model nanoparticles with chitosan. The tested model welding nanoparticles are inhaled and that A549 cells are a human lung epithelial cell line. Measurements of in vitro cytotoxicity in A549 cells revealed that the passivated nanoparticles had a lower cytotoxicity (>65% in average cell viability, counter-flow) than the untreated model nanoparticles. Moreover, the co-flow incorporation between the nanoparticles and chitosan induced passivation of the nanoparticles, and the average cell viability increased by >80% compared to the model welding nanoparticles. As a more convenient way (additional chitosan generation and incorporation devices may not be required), other passivation strategies through a modification of the welding rod with chitosan adhesive and graphite paste did also enhance average cell viability (>58%). The approach outlined in this work is potentially generalizable as a new platform, using only biocompatible materials in situ, to treat nanoparticles before they are inhaled. Copyright © 2015 Elsevier B.V. All rights reserved.

Real-time assessment of surface interactions with titanium passivation layer by surface plasmon resonance

PubMed Central

Hirata, Isao; Yoshida, Yasuhiro; Nagaoka, Noriyuki; Hiasa, Kyou; Abe, Yasuhiko; Maekawa, Kenji; Kuboki, Takuo; Akagawa, Yasumasa; Suzuki, Kazuomi; Van Meerbeek, Bart; Messersmith, Phillip B.; Okazaki, Masayuki

2011-01-01

The high corrosion resistance and strength-to-density ratio makes titanium widely used in major industry, but also in a gamut of medical applications. Here we report for the first time on our development of a titanium passivation layer sensor that makes use of surface plasmon resonance (SPR). The deposited titanium metal layer on the sensor was passivated in air, like titanium medical devices. Our ‘Ti-SPR sensor’ enables analysis of biomolecules interactions with the passivated surface of titanium in real time. As a proof of concept, corrosion of titanium passivation layer exposed to acid was monitored in real time. Also, the Ti-SPR sensor can accurately measure the time-dependence of protein adsorption onto titanium passivation layer with a sub-nanogram per square millimeter accuracy. Besides such SPR analyses, an SPR-imaging (SPRI) enables real-time assessment of chemical surface processes that occur simultaneously at ‘multiple independent spots’ on the Ti-SPR sensor, such as acid-corrosion or adhesion of cells. Our Ti-SPR sensor will therefore be very useful to study titanium-corrosion phenomena and biomolecular titanium-surface interactions with application in a broad range of industrial and biomedical fields. PMID:22154862

Managed Moves: School and Local Authority Staff Perceptions of Processes, Success and Challenges

ERIC Educational Resources Information Center

Bagley, Christopher; Hallam, Susan

2015-01-01

The current research aimed to increase understanding of the processes of managed moves for children at risk of exclusion from school, particularly exploring what contributed to success and the nature of the challenges experienced. The study was conducted in one English local authority where 11 school staff and 5 local authority staff were…

Functional hemispheric asymmetries of global/local processing mirrored by the steady-state visual evoked potential.

PubMed

Martens, Ulla; Hübner, Ronald

2013-03-01

While hemispheric differences in global/local processing have been reported by various studies, it is still under dispute at which processing stage they occur. Primarily, it was assumed that these asymmetries originate from an early perceptual stage. Instead, the content-level binding theory (Hübner & Volberg, 2005) suggests that the hemispheres differ at a later stage at which the stimulus information is bound to its respective level. The present study tested this assumption by means of steady-state evoked potentials (SSVEPs). In particular, we presented hierarchical letters flickering at 12Hz while participants categorised the letters at a pre- cued level (global or local). The information at the two levels could be congruent or incongruent with respect to the required response. Since content-binding is only necessary if there is a response conflict, asymmetric hemispheric processing should be observed only for incongruent stimuli. Indeed, our results show that the cue and congruent stimuli elicited equal SSVEP global/local effects in both hemispheres. In contrast, incongruent stimuli elicited lower SSVEP amplitudes for a local than for a global target level at left posterior electrodes, whereas a reversed pattern was seen at right hemispheric electrodes. These findings provide further evidence for a level-specific hemispheric advantage with respect to content-level binding. Moreover, the fact that the SSVEP is sensitive to these processes offers the possibility to separately track global and local processing by presenting both level contents with different frequencies. Copyright © 2012 Elsevier Inc. All rights reserved.

Interferometric inversion for passive imaging and navigation

DTIC Science & Technology

2017-05-01

AFRL-AFOSR-VA-TR-2017-0096 Interferometric inversion for passive imaging and navigation Laurent Demanet MASSACHUSETTS INSTITUTE OF TECHNOLOGY Final...COVERED (From - To) Feb 2015-Jan 2017 4. TITLE AND SUBTITLE Interferometric inversion for passive imaging and navigation 5a. CONTRACT NUMBER...Grant title: Interferometric inversion for passive imaging and navigation • Grant number: FA9550-15-1-0078 • Period: Feburary 2015 - January 2017

Temperature initiated passive cooling system

DOEpatents

Forsberg, C.W.

1994-11-01

A passive cooling system for cooling an enclosure only when the enclosure temperature exceeds a maximum standby temperature comprises a passive heat transfer loop containing heat transfer fluid having a particular thermodynamic critical point temperature just above the maximum standby temperature. An upper portion of the heat transfer loop is insulated to prevent two phase operation below the maximum standby temperature. 1 fig.

Temperature initiated passive cooling system

DOEpatents

Forsberg, Charles W.

1994-01-01

A passive cooling system for cooling an enclosure only when the enclosure temperature exceeds a maximum standby temperature comprises a passive heat transfer loop containing heat transfer fluid having a particular thermodynamic critical point temperature just above the maximum standby temperature. An upper portion of the heat transfer loop is insulated to prevent two phase operation below the maximum standby temperature.

Anomalous scaling of passive scalars in rotating flows.

PubMed

Rodriguez Imazio, P; Mininni, P D

2011-06-01

We present results of direct numerical simulations of passive scalar advection and diffusion in turbulent rotating flows. Scaling laws and the development of anisotropy are studied in spectral space, and in real space using an axisymmetric decomposition of velocity and passive scalar structure functions. The passive scalar is more anisotropic than the velocity field, and its power spectrum follows a spectral law consistent with ~ k[Please see text](-3/2). This scaling is explained with phenomenological arguments that consider the effect of rotation. Intermittency is characterized using scaling exponents and probability density functions of velocity and passive scalar increments. In the presence of rotation, intermittency in the velocity field decreases more noticeably than in the passive scalar. The scaling exponents show good agreement with Kraichnan's prediction for passive scalar intermittency in two dimensions, after correcting for the observed scaling of the second-order exponent.

Wireless passive radiation sensor

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

Pfeifer, Kent B; Rumpf, Arthur N; Yelton, William G

2013-12-03

A novel measurement technique is employed using surface acoustic wave (SAW) devices, passive RF, and radiation-sensitive films to provide a wireless passive radiation sensor that requires no batteries, outside wiring, or regular maintenance. The sensor is small (<1 cm.sup.2), physically robust, and will operate unattended for decades. In addition, the sensor can be insensitive to measurement position and read distance due to a novel self-referencing technique eliminating the need to measure absolute responses that are dependent on RF transmitter location and power.

Nitridation of SiO2 for surface passivation

NASA Technical Reports Server (NTRS)

Lai, S. K. C.

1985-01-01

An attempt is made to relate the electrical properties of silicon dioxide film to the process history. A model is proposed to explain some of the observed results. It is shown that with our present knowledge of the dielectric, silicon dioxide film shows a lot of promise for its use in surface passivation, both for its resistance to impurity diffusion and for its resistance to radiation damage effects.

Passivation Effect of Atomic Layer Deposition of Al2O3 Film on HgCdTe Infrared Detectors

NASA Astrophysics Data System (ADS)

Zhang, Peng; Ye, Zhen-Hua; Sun, Chang-Hong; Chen, Yi-Yu; Zhang, Tian-Ning; Chen, Xin; Lin, Chun; Ding, Ring-Jun; He, Li

2016-09-01

The passivation effect of atomic layer deposition of (ALD) Al2O3 film on a HgCdTe infrared detector was investigated in this work. The passivation effect of Al2O3 film was evaluated by measuring the minority carrier lifetime, capacitance versus voltage ( C- V) characteristics of metal-insulator-semiconductor devices, and resistance versus voltage ( R- V) characteristics of variable-area photodiodes. The minority carrier lifetime, C- V characteristics, and R- V characteristics of HgCdTe devices passivated by ALD Al2O3 film was comparable to those of HgCdTe devices passivated by e-beam evaporation of ZnS/CdTe film. However, the baking stability of devices passivated by Al2O3 film is inferior to that of devices passivated by ZnS/CdTe film. In future work, by optimizing the ALD Al2O3 film growing process and annealing conditions, it may be feasible to achieve both excellent electrical properties and good baking stability.

The contribution of local and transport processes to phytoplankton biomass variability over different timescales in the Upper James River, Virginia

NASA Astrophysics Data System (ADS)

Qin, Qubin; Shen, Jian

2017-09-01

Although both local processes (photosynthesis, respiration, grazing, and settling), and transport processes (advective transport and diffusive transport) significantly affect local phytoplankton dynamics, it is difficult to separate their contributions and to investigate the relative importance of each process to the local variability of phytoplankton biomass over different timescales. A method of using the transport rate is introduced to quantify the contribution of transport processes. By combining the time-varying transport rate and high-frequency observed chlorophyll a data, we can explicitly examine the impact of local and transport processes on phytoplankton biomass over a range of timescales from hourly to annually. For the Upper James River, results show that the relative importance of local and transport processes differs on different timescales. Local processes dominate phytoplankton variability on daily to weekly timescales, whereas the contribution of transport processes increases on seasonal to annual timescales and reaches equilibrium with local processes. With the use of the transport rate and high-frequency chlorophyll a data, a method similar to the open water oxygen method for metabolism is also presented to estimate phytoplankton primary production.

[Spectroscopic study on film formation mechanism and structure of composite silanes-V-Zr passive film].

PubMed

Wang, Lei; Liu, Chang-sheng; Shi, Lei; An, Cheng-qiang

2015-02-01

A composite silanes-V-Zr passive film was overlayed on hot-dip galvanized steel. Attenuated total reflection Fourier transformed infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectrometer (XPS) and radio frequency glow discharge optical emission spectrometry (rf-GD-OES) were used to characterize the molecular structure of the silanes-V-Zr passive film. The mechanism of film formation was discussed: The results show that the silane molecules are crosslinked as the main film former and inorganic inhibitor is even distributed in the film. The fitting peak of 100.7 eV in XPS single Si2p energy range spectra of the composite silanes-V-Zr passive film and the widening and strengthening of the Si--O infrared absorption peak at 1100 cm(-1) indicate that the silanes were adsorbed on the surface of zinc with chemical bond of Si--O--Zn, and the silane molecules were connected with each other by bond of Si--O--Si. Two characteristic absorption peaks of amide at 1650 and 1560 cm(-1) appear in the infrared spectroscopy of the composite silanes-V-Zr passive film, and a characteristic absorption peak of epoxy groups at 910 cm(-1) disappears in the infrared spectroscopy of the passive film. The results indicate that gamma-APT can be prepared through nucleophilic ring-opening of ethylene oxide in gamma-GPT molecule to form C--N covalent bonds. The rf-GD-OES results indicate that there is a oxygen enriched layer in 0.3 microm depth of the composite silanes-V-Zr passive film. Moreover, ZrF4, ZrO2 and some inorganic matter obtained by the reaction during the forming processof the composite silanes-V-Zr passive film are distributed evenly throughout the film. According to the film composition, the physical processes and chemical reactions during the film forming process were studied by using ATR-FTIR. Based on this, the film forming mechanism was proposed.

Investigation of radio astronomy image processing techniques for use in the passive millimetre-wave security screening environment

NASA Astrophysics Data System (ADS)

Taylor, Christopher T.; Hutchinson, Simon; Salmon, Neil A.; Wilkinson, Peter N.; Cameron, Colin D.

2014-06-01

Image processing techniques can be used to improve the cost-effectiveness of future interferometric Passive MilliMetre Wave (PMMW) imagers. The implementation of such techniques will allow for a reduction in the number of collecting elements whilst ensuring adequate image fidelity is maintained. Various techniques have been developed by the radio astronomy community to enhance the imaging capability of sparse interferometric arrays. The most prominent are Multi- Frequency Synthesis (MFS) and non-linear deconvolution algorithms, such as the Maximum Entropy Method (MEM) and variations of the CLEAN algorithm. This investigation focuses on the implementation of these methods in the defacto standard for radio astronomy image processing, the Common Astronomy Software Applications (CASA) package, building upon the discussion presented in Taylor et al., SPIE 8362-0F. We describe the image conversion process into a CASA suitable format, followed by a series of simulations that exploit the highlighted deconvolution and MFS algorithms assuming far-field imagery. The primary target application used for this investigation is an outdoor security scanner for soft-sided Heavy Goods Vehicles. A quantitative analysis of the effectiveness of the aforementioned image processing techniques is presented, with thoughts on the potential cost-savings such an approach could yield. Consideration is also given to how the implementation of these techniques in CASA might be adapted to operate in a near-field target environment. This may enable a much wider usability by the imaging community outside of radio astronomy and thus would be directly relevant to portal screening security systems in the microwave and millimetre wave bands.

Achieving Passive Localization with Traffic Light Schedules in Urban Road Sensor Networks

PubMed Central

Niu, Qiang; Yang, Xu; Gao, Shouwan; Chen, Pengpeng; Chan, Shibing

2016-01-01

Localization is crucial for the monitoring applications of cities, such as road monitoring, environment surveillance, vehicle tracking, etc. In urban road sensor networks, sensors are often sparely deployed due to the hardware cost. Under this sparse deployment, sensors cannot communicate with each other via ranging hardware or one-hop connectivity, rendering the existing localization solutions ineffective. To address this issue, this paper proposes a novel Traffic Lights Schedule-based localization algorithm (TLS), which is built on the fact that vehicles move through the intersection with a known traffic light schedule. We can first obtain the law by binary vehicle detection time stamps and describe the law as a matrix, called a detection matrix. At the same time, we can also use the known traffic light information to construct the matrices, which can be formed as a collection called a known matrix collection. The detection matrix is then matched in the known matrix collection for identifying where sensors are located on urban roads. We evaluate our algorithm by extensive simulation. The results show that the localization accuracy of intersection sensors can reach more than 90%. In addition, we compare it with a state-of-the-art algorithm and prove that it has a wider operational region. PMID:27735871

Acoustic Source Localization via Time Difference of Arrival Estimation for Distributed Sensor Networks Using Tera-Scale Optical Core Devices

DOE PAGES

Imam, Neena; Barhen, Jacob

2009-01-01

For real-time acoustic source localization applications, one of the primary challenges is the considerable growth in computational complexity associated with the emergence of ever larger, active or passive, distributed sensor networks. These sensors rely heavily on battery-operated system components to achieve highly functional automation in signal and information processing. In order to keep communication requirements minimal, it is desirable to perform as much processing on the receiver platforms as possible. However, the complexity of the calculations needed to achieve accurate source localization increases dramatically with the size of sensor arrays, resulting in substantial growth of computational requirements that cannot bemore » readily met with standard hardware. One option to meet this challenge builds upon the emergence of digital optical-core devices. The objective of this work was to explore the implementation of key building block algorithms used in underwater source localization on the optical-core digital processing platform recently introduced by Lenslet Inc. This demonstration of considerably faster signal processing capability should be of substantial significance to the design and innovation of future generations of distributed sensor networks.« less

An automated cross-correlation based event detection technique and its application to surface passive data set

USGS Publications Warehouse

Forghani-Arani, Farnoush; Behura, Jyoti; Haines, Seth S.; Batzle, Mike

2013-01-01

In studies on heavy oil, shale reservoirs, tight gas and enhanced geothermal systems, the use of surface passive seismic data to monitor induced microseismicity due to the fluid flow in the subsurface is becoming more common. However, in most studies passive seismic records contain days and months of data and manually analysing the data can be expensive and inaccurate. Moreover, in the presence of noise, detecting the arrival of weak microseismic events becomes challenging. Hence, the use of an automated, accurate and computationally fast technique for event detection in passive seismic data is essential. The conventional automatic event identification algorithm computes a running-window energy ratio of the short-term average to the long-term average of the passive seismic data for each trace. We show that for the common case of a low signal-to-noise ratio in surface passive records, the conventional method is not sufficiently effective at event identification. Here, we extend the conventional algorithm by introducing a technique that is based on the cross-correlation of the energy ratios computed by the conventional method. With our technique we can measure the similarities amongst the computed energy ratios at different traces. Our approach is successful at improving the detectability of events with a low signal-to-noise ratio that are not detectable with the conventional algorithm. Also, our algorithm has the advantage to identify if an event is common to all stations (a regional event) or to a limited number of stations (a local event). We provide examples of applying our technique to synthetic data and a field surface passive data set recorded at a geothermal site.

Room-Temperature-Processed Flexible Amorphous InGaZnO Thin Film Transistor.

PubMed

Xiao, Xiang; Zhang, Letao; Shao, Yang; Zhou, Xiaoliang; He, Hongyu; Zhang, Shengdong

2017-12-13

A room-temperature flexible amorphous indium-gallium-zinc oxide thin film transistor (a-IGZO TFT) technology is developed on plastic substrates, in which both the gate dielectric and passivation layers of the TFTs are formed by an anodic oxidation (anodization) technique. While the gate dielectric Al 2 O 3 is grown with a conventional anodization on an Al:Nd gate electrode, the channel passivation layer Al 2 O 3 is formed using a localized anodization technique. The anodized Al 2 O 3 passivation layer shows a superior passivation effect to that of PECVD SiO 2 . The room-temperature-processed flexible a-IGZO TFT exhibits a field-effect mobility of 7.5 cm 2 /V·s, a subthreshold swing of 0.44 V/dec, an on-off ratio of 3.1 × 10 8 , and an acceptable gate-bias stability with threshold voltage shifts of 2.65 and -1.09 V under positive gate-bias stress and negative gate-bias stress, respectively. Bending and fatigue tests confirm that the flexible a-IGZO TFT also has a good mechanical reliability, with electrical performances remaining consistent up to a strain of 0.76% as well as after 1200 cycles of fatigue testing.

Vertical Diffusivities of Active and Passive Tracers

NASA Technical Reports Server (NTRS)

Canuto, V. M.; Cheng, Y.; Howard, A. M.

2010-01-01

The climate models that include a carbon-cycle need the vertical diffusivity of a passive tracer. Since an expression for the latter is not available, it has been common practice to identify it with that of salt. The identification is questionable since T, S are active, not passive tracers. We present the first derivation of the diffusivity of a passive tracer in terms of Ri (Richardson number) and Rq (density ratio, ratio of salinity over temperature z-gradients). The following results have emerged: (a) The passive tracer diffusivity is an algebraic function of Ri, Rq. (b) In doubly stable regimes (DS, partial derivative of T with respect to z > 0, partial derivative of S with respect to z < 0), the passive scalar diffusivity is nearly the same as that of salt/heat for any values of Rq < 0 and Ri > 0. (c) In DC regimes (diffusive convection, partial derivative of T with respect to z < 0, partial derivative of S with respect to z < 0, Rq > 1), the passive scalar diffusivity is larger than that of salt. At Ri = O(1), it can be more than twice as large. (d) In SF regimes (salt fingers, partial derivative of T with respect to z > 0, partial derivative of S with respect to z > 0, Rq < 1), the passive scalar diffusivity is smaller than that of salt. At Ri = O(1), it can be less than half of it. (e) The passive tracer diffusivity predicted at the location of NATRE (North Atlantic Tracer Release Experiment) is discussed. (f) Perhaps the most relevant conclusion is that the common identification of the tracer diffusivity with that of salt is valid only in DS regimes. In the Southern Ocean, where there is the largest CO2 absorption, the dominant regime is diffusive convection discussed in (c) above.

Antenna for passive RFID tags

NASA Astrophysics Data System (ADS)

Schiopu, Paul; Manea, Adrian; Cristea, Ionica; Grosu, Neculai; Vladescu, Marian; Craciun, Anca-Ileana; Craciun, Alexandru

2015-02-01

Minuscule devices, called RFID tags are attached to objects and persons and emit information which positioned readers may capture wirelessly. Many methods of identification have been used, but that of most common is to use a unique serial number for identification of person or object. RFID tags can be characterized as either active or passive [1,2]. Traditional passive tags are typically in "sleep" state until awakened by the reader's emitted field. In passive tags, the reader's field acts to charge the capacitor that powers the badge and this can be a combination of antenna and barcodes obtained with SAW( Surface Acoustic Wave) devices [1,2,3] . The antenna in an RFID tag is a conductive element that permits the tag to exchange data with the reader. The paper contribution are targeted to antenna for passive RFID tags. The electromagnetic field generated by the reader is somehow oriented by the reader antenna and power is induced in the tag only if the orientation of the tag antenna is appropriate. A tag placed orthogonal to the reader yield field will not be read. This is the reason that guided manufacturers to build circular polarized antenna capable of propagating a field that is alternatively polarized on all planes passing on the diffusion axis. Passive RFID tags are operated at the UHF frequencies of 868MHz (Europe) and 915MHz (USA) and at the microwave frequencies of 2,45 GHz and 5,8 GHz . Because the tags are small dimensions, in paper, we present the possibility to use circular polarization microstrip antenna with fractal edge [2].

Passive cooling during transport of asphyxiated term newborns

PubMed Central

O’Reilly, Deirdre; Labrecque, Michelle; O’Melia, Michael; Bacic, Janine; Hansen, Anne; Soul, Janet S

2014-01-01

Objective To evaluate the efficacy and safety of passive cooling during transport of asphyxiated newborns. Study Design Retrospective medical record review of newborns with perinatal asphyxia transported for hypothermia between July 2007 and June 2010. Results Forty-three newborns were transported, 27 of whom were passively cooled. Twenty (74%) passively cooled newborns arrived with axillary temperature between 32.5 and 34.5 °C. One newborn (4%) arrived with a subtherapeutic temperature, and 6 (22%) had temperatures >34.5 °C. Time from birth to hypothermia was significantly shorter among passively cooled newborns compared with newborns not cooled (215 vs. 327 minutes, p<0.01), even though time from birth to arrival was similar (252 vs. 259 minutes, p=0.77). There were no significant adverse events related to passive cooling. Conclusions Exclusive passive cooling for hypoxic-ischemic encephalopathy results in significantly earlier achievement of effective therapeutic hypothermia without significant adverse events. PMID:23154670

Differential effects of cognitive load on emotion: Emotion maintenance versus passive experience.

PubMed

DeFraine, William C

2016-06-01

Two separate lines of research have examined the effects of cognitive load on emotional processing with similar tasks but seemingly contradictory results. Some research has shown that the emotions elicited by passive viewing of emotional images are reduced by subsequent cognitive load. Other research has shown that such emotions are not reduced by cognitive load if the emotions are actively maintained. The present study sought to compare and resolve these 2 lines of research. Participants either passively viewed negative emotional images or maintained the emotions elicited by the images, and after a delay rated the intensity of the emotion they were feeling. Half of trials included a math task during the delay to induce cognitive load, and the other half did not. Results showed that cognitive load reduced the intensity of negative emotions during passive-viewing of emotional images but not during emotion maintenance. The present study replicates the findings of both lines of research, and shows that the key factor is whether or not emotions are actively maintained. Also, in the context of previous emotion maintenance research, the present results support the theoretical idea of a separable emotion maintenance process. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Active subjects of passive monitoring: responses to a passive monitoring system in low-income independent living

PubMed Central

BERRIDGE, CLARA

2016-01-01

Passive monitoring technology is beginning to be reimbursed by third-party payers in the United States of America. Given the low voluntary uptake of these technologies on the market, it is important to understand the concerns and perspectives of users, former users and non-users. In this paper, the range of ways older adults relate to passive monitoring in low-income independent-living residences is presented. This includes experiences of adoption, non-adoption, discontinuation and creative ‘misuse’. The analysis of interviews reveals three key insights. First, assumptions built into the technology about how older adults live present a problem for many users who experience unwanted disruptions and threats to their behavioural autonomy. Second, resident response is varied and challenges the dominant image of residents as passive subjects of a passive monitoring system. Third, the priorities of older adults (e.g. safety, autonomy, privacy, control, contact) are more diverse and multi-faceted than those of the housing organisation staff and family members (e.g. safety, efficiency) who drive the passive monitoring intervention. The tension between needs, desires and the daily lives of older adults and the technological solutions offered to them is made visible by their active responses, including resistance to them. This exposes the active and meaningful qualities of older adults’ decisions and practices. PMID:28239211

The Development of Global and Local Processing: A Comparison of Children to Adults

ERIC Educational Resources Information Center

Peterson, Eric; Peterson, Robin L.

2014-01-01

In light of the adult model of a hemispheric asymmetry of global and local processing, we compared children (M [subscript age] = 8.4 years) to adults in a global-local reaction time (RT) paradigm. Hierarchical designs (large shapes made of small shapes) were presented randomly to each visual field, and participants were instructed to identify…

Low cost passive solar adobe house

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

Not Available

1981-12-21

A brief description, photographs, and cost breakdown of a hybrid direct-gain passive solar adobe house constructed in the City of El Paso, Texas. The 3-panel active solar domestic hot water system acts as a back-up to the direct gain passive system.

Passive acoustic source localization using sources of opportunity.

PubMed

Verlinden, Christopher M A; Sarkar, J; Hodgkiss, W S; Kuperman, W A; Sabra, K G

2015-07-01

The feasibility of using data derived replicas from ships of opportunity for implementing matched field processing is demonstrated. The Automatic Identification System (AIS) is used to provide the library coordinates for the replica library and a correlation based processing procedure is used to overcome the impediment that the replica library is constructed from sources with different spectra and will further be used to locate another source with its own unique spectral structure. The method is illustrated with simulation and then verified using acoustic data from a 2009 experiment for which AIS information was retrieved from the United States Coast Guard Navigation Center Nationwide AIS database.

Passive Solar Heating Residences.

DTIC Science & Technology

1979-07-01

concerned, as long as the basic system falls within one of the passive concepts, then it is a passive system. If a fan can increase the system~s...wood walls and roof is R-22, in the block walls (urea-formaldahyde foam sprayed in wall cavity) is R-30, and a 4" styro- foam board at the slab edge (R...is based cn 1,000 BTU/sq. ft./day, which is a clear day value. The south windows have reflectors which will increase the energy gained (30% by Steve

Numerical study of comparison of vorticity and passive vectors in turbulence and inviscid flows

NASA Astrophysics Data System (ADS)

Ohkitani, Koji

2002-04-01

The nonlinear vortex stretching in incompressible Navier-Stokes turbulence is compared with a linear stretching process of passive vectors (PVs). In particular, we pay special attention to the difference of these processes under long and short time evolutions. For finite time evolution, we confirm our previous finding that the stretching effect of vorticity is weaker than that of general passive vectors for a majority of the initial conditions with the same energy spectra. The above difference can be explained qualitatively by examining the Biot-Savart formula. In order to see to what extent infinitesimal time development explains the above difference, we examine the probability density functions (PDFs) of the stretching rates of the passive vectors in the vicinity of a solution of Navier-Stokes equations. It is found that the PDFs are found to have a Gaussian distribution, suggesting that there are equally many PVs that stretched less and more than the vorticity. This suggests the importance of the vorticity-strain correlation built up over finite time in turbulence. We also discuss the case of Euler equations, where the dynamics of the Jacobian matrix relating the physical and material coordinates is examined numerically. A kind of alignment problem associated with the Cauchy-Green tensor is proposed and studied using the results of numerical simulations. It is found that vorticity tends to align itself with the most compressing eigenvector of the Cauchy-Green tensor. A two-dimensional counterpart of active-passive comparison is briefly studied. There is no essential difference between stretching of vorticity gradients and that of passive scalar gradients and a physical interpretation is given to it.

Chemical passivation as a method of improving the electrochemical corrosion resistance of Co-Cr-based dental alloy.

PubMed

Rylska, Dorota; Sokołowski, Grzegorz; Sokołowski, Jerzy; Łukomska-Szymańska, Monika

2017-01-01

The purpose of the study was to evaluate corrosion resistance of Wirobond C® alloy after chemical passivation treatment. The alloy surface undergone chemical passivation treatment in four different media. Corrosion studies were carried out by means of electrochemical methods in saline solution. Corrosion effects were determined using SEM. The greatest increase in the alloy polarization resistance was observed for passive layer produced in Na2SO4 solution with graphite. The same layer caused the highest increase in corrosion current. Generally speaking, the alloy passivation in Na2SO4 solution with graphite caused a substantial improvement of the corrosion resistance. The sample after passivation in Na2SO4 solution without graphite, contrary to others, lost its protective properties along with successive anodic polarization cycles. The alloy passivation in Na3PO4 solution with graphite was the only one that caused a decrease in the alloy corrosion properties. The SEM studies of all samples after chemical passivation revealed no pit corrosion - in contrast to the sample without any modification. Every successive polarization cycle in anodic direction of pure Wirobond C® alloy enhances corrosion resistance shifting corrosion potential in the positive direction and decreasing corrosion current value. The chemical passivation in solutions with low pH values decreases susceptibility to electrochemical corrosion of Co-Cr dental alloy. The best protection against corrosion was obtained after chemical passivation of Wirobond C® in Na2SO4 solution with graphite. Passivation with Na2SO4 in solution of high pH does not cause an increase in corrosion resistance of WIROBOND C. Passivation process increases alloy resistance to pit corrosion.

Camera calibration: active versus passive targets

NASA Astrophysics Data System (ADS)

Schmalz, Christoph; Forster, Frank; Angelopoulou, Elli

2011-11-01

Traditionally, most camera calibrations rely on a planar target with well-known marks. However, the localization error of the marks in the image is a source of inaccuracy. We propose the use of high-resolution digital displays as active calibration targets to obtain more accurate calibration results for all types of cameras. The display shows a series of coded patterns to generate correspondences between world points and image points. This has several advantages. No special calibration hardware is necessary because suitable displays are practically ubiquitious. The method is fully automatic, and no identification of marks is necessary. For a coding scheme based on phase shifting, the localization accuracy is approximately independent of the camera's focus settings. Most importantly, higher accuracy can be achieved compared to passive targets, such as printed checkerboards. A rigorous evaluation is performed to substantiate this claim. Our active target method is compared to standard calibrations using a checkerboard target. We perform camera, calibrations with different combinations of displays, cameras, and lenses, as well as with simulated images and find markedly lower reprojection errors when using active targets. For example, in a stereo reconstruction task, the accuracy of a system calibrated with an active target is five times better.

Passive Superconducting Shielding: Experimental Results and Computer Models

NASA Technical Reports Server (NTRS)

Warner, B. A.; Kamiya, K.

2003-01-01

Passive superconducting shielding for magnetic refrigerators has advantages over active shielding and passive ferromagnetic shielding in that it is lightweight and easy to construct. However, it is not as easy to model and does not fail gracefully. Failure of a passive superconducting shield may lead to persistent flux and persistent currents. Unfortunately, modeling software for superconducting materials is not as easily available as is software for simple coils or for ferromagnetic materials. This paper will discuss ways of using available software to model passive superconducting shielding.

Configurations and calibration methods for passive sampling techniques.

PubMed

Ouyang, Gangfeng; Pawliszyn, Janusz

2007-10-19

Passive sampling technology has developed very quickly in the past 15 years, and is widely used for the monitoring of pollutants in different environments. The design and quantification of passive sampling devices require an appropriate calibration method. Current calibration methods that exist for passive sampling, including equilibrium extraction, linear uptake, and kinetic calibration, are presented in this review. A number of state-of-the-art passive sampling devices that can be used for aqueous and air monitoring are introduced according to their calibration methods.

Print media coverage of research on passive smoking

PubMed Central

Kennedy, G.; Bero, L.

1999-01-01

OBJECTIVE—To assess the extent and content of newspaper and magazine coverage of research on passive smoking.
DESIGN—Content analysis of newspaper and magazine articles.
SUBJECTS—Articles reporting on passive smoking research published in newspapers (n = 180) or magazines (n = 92) between January 1981 and December 1994.
MAIN OUTCOME MEASURES—Numbers of articles, conclusions of articles, sources quoted, numbers and characteristics of research studies cited, presence of tobacco advertising.
RESULTS—The number of newspaper and magazine articles reporting on passive smoking research increased from four in 1981 to 57 in 1992 and 32 in 1994. Sixty-two per cent (168/272) of articles concluded that the research on passive smoking is controversial. Tobacco industry representatives were quoted significantly more often in newspaper articles (52%, 94/180) than magazine articles (12%, 11/92) (p<0.0001). Of 121 different research studies cited in the lay press articles, only 15 were from tobacco-industry sponsored projects or publications. In magazines, acceptance of tobacco industry advertising was associated with the conclusion that research on passive smoking is controversial (p<0.0001).
CONCLUSIONS—Although research on the harmful effects of passive smoking accumulated between 1981 and 1994, lay press coverage of the research maintained that the science was controversial. Few research studies were cited to support the industry's claim that passive smoking is not harmful to health. However, tobacco industry representatives who were critical of the research methods used to study the health effects of passive smoking were frequently quoted.


Keywords: environmental tobacco smoke; media; passive smoking PMID:10599568